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The high-frequency (HF) signal injection methods have been widely used for the low-speed sensorless control of permanent magnet motor under vector control framework. However, for the fault tolerant permanent magnet synchronous motor (FTPMSM) system under fault condition, the fault tolerant control is usually based on independent control of each phase current, rather than the vector control, which prevents the existing sensorless control from being directly applied. To cope with this issue, this paper proposes a novel sensorless control by HF signal injection in any non-fault two phase windings for the FTPMSM system with no coordinate transformation, which can ensure the low- and zero-speed sensorless control performance both in fault-free and fault tolerant operation conditions. This sensorless control scheme is based on independent control framework of each phase current, which consists of the real-time inductance observer, the non-orthogonal phase-locked loop (NPLL), the notch filter and the polarity discrimination of magnet pole. The real-time inductance observer is proposed to estimate the differential mode inductances of two non-fault phase. The NPLL is proposed to achieve the rotor position and speed estimation based on the obtained two phase inductances. To enhance the sensorless control performance, a new notch filter is proposed to filter out the injected HF response component in phase current. The proposed sensorless FTPMSM system has preeminent low-speed control performance and robustness in non-fault and fault tolerant operation process, which is also verified via experiments on a six-phase FTPMSM platform.

Different from typical circuit breakers, breakers used to switch AC filters in convertor stations have to operate frequently according to the real-time operation mode and daily load changes. Therefore, the performance of filter breakers decreases very quickly, which leads to frequent accidents. Both preinsertion resistors and controlled switching devices can suppress switching transients. In this paper, a comparative analysis of whether a controlled switching device and preinsertion resistor should be adopted is carried out using PSCAD. The transient is calculated as the combined result of the switching angle and preinsertion resistor value, and the optimal configurations are proposed. After determining the resistor value and whether a controlled switching device should be included, the reference voltage of the arrester should be reevaluated.

The three-phase dual active bridge (3p-DAB) is a popular topology suitable for high power DC-DC isolated conversion. This converter features bi-directional power flow, zero-voltage switching capability, and reduced transformer and filter volume. These features meet the requirements of several applications, such as solid-state transformers. But when operating under light load the resulting converter efficiency is highly degraded by the loss of soft-switching capability. This paper introduces the use of a Wye-extended-Delta (Y-e) transformer winding in the 3p-DAB converter, which increases the efficiency under light load, keeping the simplicity of phase-shift control. The framework developed allows a complete analysis of the converter, including the determination of the power and rms current, zero-voltage switching boundaries and the impact of the selected phase-shifting angle in the transformer design. Additionally, this paper presents a negative sequence modulation scheme, allowing maximum efficiency under light loads to be achieved for both direct and reverse power flows. The performance of the 3p-DAB with Y-e transformers is compared with previously reported winding options for 3p-DAB. The experimental results show a converter efficiency increase, up to 10\% for direct power flow and up to 9\% for reverse power flow, when operating at light load (10\% of nominal power).

During the past four decades the use of nonwoven geotextiles as filter materials in geotechnical works has experienced a marked increase. In this study, the water permeability coefficient of nonwoven geotextiles after 23 years of exploitation in drainage system was determined to evaluate the influence of physical clogging on filtration performance of geotextiles. The obtained results showed that the geotextiles were clogged by soil particles. What is more, the objective in this study was to establish a gradient ratio test method for estimating a clogging phenomenon of geotextile filter adequately. A series of gradient ratio tests on three kinds of needle-punched nonwoven geotextile filters whose number of constrictions differs was performed. A geotextile filter was put under a silty sand layer. Based on the test results, it was confirmed that the water permeability coefficient became small as the gradient ratio increased, depending on the number of constrictions of the geotextile. It was also found that the modified gradient ratio GR4 is more sensitive than GR8 and GR25. Based on interpretation of the experimental results, the authors recommend the acceptance limit of GR8 equal to 3.7 and of GR4 equal to 4.8.

The design of electromagnetic interference (EMI) filter with smaller size and lightweight for a high efficiency and high power density 100 kW SiC five-level T-type (5LT2) photovoltaic (PV) inverter becomes more challenging due to the increased EMI noise resulted by high switching frequency, fast switching transients, and the removal of LCL filter. This paper proposes an unbalanced Wheatstone bridge and a two-stage notch filter to attenuate the increased common mode (CM) and differential mode (DM) noise respectively. The conventional Wheatstone bridge will suffer size and weight penalty for 100 kW PV converter due to the high parasitic capacitance of the 100 kW PV panel. An unbalanced Wheatstone bridge with a one-stage LC filter is therefore developed to address this issue and reduce the total CM inductance. The proposed two-stage notch filter is designed to achieve high attenuation, solve its parameter variation issue and help reduce the size and weight of DM filter. The total weight of the designed EMI filter for this 100 kW PV inverter is 3.54 kg. The measured conducted EMI spectrum of the 100 kW SiC PV inverter with and without proposed EMI filter are provided to validate the effectiveness of the EMI filter design.

This work presents three single-phase isolated ac-ac converters based on the dual active bridge (DAB) converter and interleaved transformers. The structures allow obtaining filter elements with reduced dimensions, as well as bidirectional power flow and high efficiency over a wide load range. Multilevel voltage waveforms exist in the input and output sides of the symmetrical converters, resulting in reduced harmonic content. The possible arrangements include a symmetrical half-bridge converter (SHBC), a symmetrical full-bridge converter (SFBC), and a symmetrical interleaved full-bridge converter (SIFBC). The introduced topologies can be regarded as prominent solutions for applications involving solid-state transformers (SSTs), dynamic voltage restorers (DVRs), and uninterruptible power supplies (UPSs). A thorough mathematical analysis of the SHBC is carried out and experimental results are presented to investigate the converter performance in steady-state and transient conditions.

We show theoretically and experimentally how a flat-top second-order response can be achieved with a self-coupled single add-drop ring resonator based on two couplers with different splitting ratios. The resulting device is a 1x1 filter, reflecting light back in the input waveguide at resonating wavelengths in the passbands, and transmitting light in the output waveguide at all other non-resonating wavelengths. Different implementations of the filter have been designed and fabricated on a micron-scale silicon photonics platform. They are based on compact Euler bends - either U-bends or L-bends - and Multi-Mode Interferometers as splitters for the ring resonators. Different finesse values have been achieved by using either 50:50 MMIs in conjunction with 85:15 MMIs or 85:15 MMIs in conjunction with 95:05 double MMIs. Unlike ordinary lowest order directional couplers, the MMIs couple most of the power in the cross-port which make them particularly suitable for the topology of the self-coupled ring, which would otherwise require a waveguide crossing. Experimental results are presented, showing good agreement with simulations. The proposed devices can find applications as wavelength-selective reflectors for relatively broad-band lasers or used as 2x2 add-drop filters when two exact replicas of the device are placed on the arms of a Mach-Zehnder interferometer., 9 pages, 17 references, 12 figures

Solid-state transformers (SSTs) have emerged as an interesting solution for replacing the traditional low-frequency transformers in power distribution systems owing to the capacity of performing ancillary services and providing the integration of multiple energy sources. This work proposes a four-port, single-phase, multi-directional ac-ac converter for SST applications. Considering the integration of conversion stages, it is possible to achieve higher efficiency and lower component count when compared with the typical three-stage topologies reported in the literature. The introduced structure is based on the interleaving concept associated with the well-known dual active bridge (DAB) converter. The medium-voltage (MV) side employs a multilevel neutral-point-clamped (NPC) converter. The voltages across the ac ports present five levels, whereas the operating frequency of the filter elements is twice the switching frequency. Experimental results are presented and thoroughly discussed to validate the theoretical assumptions.

In this paper, a new 5-level inverter is developed by inserting a switched-capacitor (SC) unit into the traditional 3-level neutral-point-clamped (NPC) inverter phase-leg. The SC unit consists of two capacitors and one bidirectional switch, all of which withstand a quarter of the dc input voltage. Whilst increasing the output levels, the performance is also improved in terms of power loss, common-mode voltage, switching stress dv/dt and output filter. Compared to other 5-level inverters like the conventional NPC and active NPC 5-level topologies, the new solution not only reduces the number of components and simplifies the design, but also has the advantage of self-balanced capacitor voltages. The analysis, simulation and experiment indicate that the proposed inverter is suitable for a wide range of applications like renewable source grid-connected interfaces and motor drivers. Simulation and experimental results of grid-connected operation verify that the new inverter is capable of providing both active and reactive power to the grid. Its excellent performance is also experimentally evaluated by a 1.2 kW prototype and the measured efficiency is above 97% for a wide range of load.

In this paper, a tuneable low-power active bandpass filter (BPF) is designed for channel selection in TSMC’s 65-nm CMOS technology. The proposed filter consists of two identical BPFs which are based on a gm-C topology, and can be controlled with a constant quality factor. The center frequency of this design can be changed to acquire a specific passband channel from 60 kHz to 2.5 MHz by adjusting the bias voltage in discrete increments, with an almost constant quality factor equal to 7.2. To validate the design, the integrated circuit and a test board are fabricated. Five passband channels are measured from the proposed design with a low power consumption equal to 68 ‘W. The measured dynamic range is equal to 51.6 dB when the total harmonic distortion (THD) is equal to 1%. Hence, the proposed controllable channel selection filter shows an excellent performance as compared to existing work and offers a great potential for use applications with heterogeneous sensor nodes.

A predistorted folded substrate integrated waveguide (FSIW) filter is developed for a flat passband. The unloaded Q-factor of FSIW cavity is predicted numerically and then applied to the coupling matrix synthesis. A filter prototype is fabricated with the low temperature cofired ceramic technology (LTCC), where the direct and cross couplings are realized in a 3D configuration. The synthesized, simulated and measured results agree well with each other. The insertion loss is 3.48 dB at 5 GHz and the 0.2-dB bandwidth is 338 MHz which is equivalent to a conventional filter with the uniform unloaded Q-factor of 870, much higher than the one of 180 provided by the applied FSIW resonator. Two transmission zeros locate at 4.50 and 5.46 GHz to improve the frequency selectivity. The filter size is only 18.04×9.2×1.4 mm3 and the occupied area is 0.72×0.37 λd2.

This paper presents the design of tunable CMOS pseudo-resistors aimed at achieving large and predictable resistance values. Instrumental to the proposed pseudo-resistor is the design of current sources of extremely low currents and transistors operating in subthreshold. The effects of the leakage currents of reverse-biased pn-junctions on the pseudo-resistor resistance are also evaluated. The proposed pseudo-resistor circuit was validated while in use as part of a filter integrated in a 180 nm CMOS process. Pseudo-resistors with resistances between 180 GΩ and 700 GΩ were employed to obtain low-frequency poles of a band-pass filter adjustable from 0.6 Hz to 2 Hz.

This work proposes an ac-ac converter based on interleaved transformers associated with the dual active bridge (DAB) converter. The resulting symmetrical full-bridge converter (SFBC) can achieve high efficiency over a wide range of the output power and bidirectional power flow, as well as high power density owing to the possible integration of magnetics. The voltage waveforms on the high-frequency transformer (HFT) present five levels, resulting in filter elements with reduced dimensions. A detailed mathematical analysis of the SFBC comprising the operating stages, modulation technique, and soft-switching range is derived. An experimental prototype rated at 1 kW is implemented to validate the theoretical assumptions, thus demonstrating that the SFBC is capable of providing input power factor correction (PFC) and a load voltage waveform with low harmonic content.

This article presents an ultracompact bandpass filter (BPF) realized by slow wave substrate integrated groove gap waveguide (SW-SIGGW). The SW-SIGGW is composed of two layers of the dielectric substrate, in which periodic mushroom-type electromagnetic band-gap (EBG) unit cells are employed as packaging structures. The gap layer is realized by the upper substrate, and the via-patch mushrooms are designed on the lower substrate. Due to the slow wave structure in the form of periodical metallic via-holes designed on the lower substrate, the guided wavelength is reduced by about 52.8% compared with normal SIGGW. A dual-band resonator and a cascaded second-order BPF are designed based on SW-SIGGW. Compared with the conventional second-order SIGGW BPF, the proposed SW-SIGGW BPF achieves a 62.6% reduction in the area. By adopting vertical stacking technology, the area of the SW-SIGGW BPF is further miniaturized. The final area of the stacked SW-SIGGW BPF is only 18.7% of the conventional filter based on normal SIGGW without slow wave and stacked structure, which is very competitive for the room-limited applications. A prototype of the stacked SW-SIGGW BPF with 5.4% and 7.4% fractional bandwidths at 11.8 and 18 GHz is fabricated and measured. A good agreement between the measured and simulated results verifies the validity of the miniaturized design of SW-SIGGW BPF.

Sterilizing filtration is a common unit operation for the manufacture of parenteral drug products. However, filter performance can be impacted by properties of both the membrane material and the solution being filtered, requiring extensive multi-factor studies to optimize the filtration process for a given drug product. Here, we report the use of a modified bundle of capillaries approximation to predict filter performance. The model is directly applicable for both Newtonian and non-Newtonian solutions and does not require assumptions of steady state. Using a hydrophilic polyvinylidene difluoride (PVDF) filter as a test case, we show that the model fitting parameters align with expected values and both flux and shear are well predicted. Moreover, two case studies are presented to demonstrate the model's utility for filtration process optimization: 1) protein adsorption of an antibody formulation and 2) filter fouling of a 1% (w/v) carboxymethylcellulose (CMC) solution. In both cases, the model was able to accurately identify optimal filtration parameters to reduce the amount of adsorption or improve the filter capacity, respectively. This methodology can be easily extended to alternate filter types and provides an additional predictive tool to speed process development and minimize trial and error during filtration process design.

Feature selection plays a key role in target recognition especially for multiple combined sensors’ applications. This study presents an improved relief feature selection (Relief‐F) model to rank features for multi‐target recognition. Besides, the evaluation of the effectiveness of the method is conducted based on the following three measuring indices: feature redundancy, class separability and overall accuracy. The simulated data acquired by radar infrared combined sensors are used to verify the metrics of the proposed method. The experimental results demonstrate that the Relief‐F method reveals the best results compared to other feature selection methods, including principal component analysis and Fisher linear discriminant analysis. It indicates that Relief‐F can be an effective option for feature selection with high‐class separability and a low feature redundancy rate. Furthermore, high overall accuracy can be obtained using a relatively small amount of features selected by the Relief‐F method.

This paper proposes a new method of constructing a compensation filter for the modulated wideband converter (MWC) system. The proposed method can be directly used in the MWC circuit without disconnecting any components. Furthermore, the non-ideal transfer characteristics of the real mixer output and the real ADC input are taken into account in the proposed compensation filter. The proposed method can be utilized in the advanced MWC that enables more flexibility in the design parameters of the MWC. This paper also demonstrates the reconstruction of the Bluetooth signal as a practical example for the evaluation of the reconstruction performance. The MWC successfully reconstructs the time-domain waveform of the signal based on the proposed compensation filter. Even in the case that the total effective number of channels in MWC is small as close to the necessary condition of the MWC, the error vector magnitude (EVM) was still under 1%, which is acceptable for Bluetooth device testing applications.

Two-dimensional (2D) crystals of conjugated polymers (2DCCPs) have attracted significant attention in the past few decades due to their superior and intriguing optoelectronic properties. With the increase in brain-inspired neuromorphic computing, 2DCCPs have also been employed in the construction of synaptic devices because they offer clear advantages of easy integration, high stability, long–range order and no biological rejection. However, pursuing controllable strategies to obtain high-quality and large-scale 2DCCPs remains a challenge on account of their intrinsic complex structures. Herein, we present a universal methodology to grow centimeter-scale 2DCCPs in a controlled manner within minutes by selecting an appropriate growth-assisting solvent and surfactant. The thickness of the as-produced 2DCCPs was down to two molecular layers. The photonic synaptic transistors based on the as-grown 2DCCPs could perform typical synaptic functions, including short-term plasticity, paired-pulse facilitation, long-term plasticity and spike intensity-dependent plasticity. The transistor was also proven to have potential application as a high-pass filter. This methodology shows great potential to be expanded to many other polymer systems and opens new pathways for large-area integrated wireless communication systems and artificial visual systems.

Rapid, efficient, and selective separation of tumor cells from complex body fluids is urgently needed for clinical application of tumor-cell-based liquid biopsy. Herein, a size-selective affinity filtration system, named Selective, User-friendly, highly Porous, Efficient, and Rapid filter (SUPER Filter), was developed for high-performance tumor cell isolation and analysis. SUPER Filter enabled selective interaction of tumor cells with size-optimized and antibody-coated micropore walls during filtration, achieving high efficiency of 91.0 ± 6.1% in PBS and 83.7 ± 6.4% in whole blood. Meanwhile, its larger micropore size than traditional filtration devices greatly reduced nonspecific capture of background cells (55-126 cells/mL blood) with enrichment factors of 1.1 × 104 - 1.0 × 105 and purity of 52.7 ± 4.2%. Moreover, its high porosity enabled ultra-fast (< 5 s for 1 mL of blood or 10 mL of buffer samples) and user-friendly gravity-driven filtration. Finally, SUPER Filter demonstrated rapid, efficient, and selective separation of tumor cells from blood and large-volume pleural and ascetic fluid samples of cancer patients for morphological and molecular analysis. We expect that this size-selective affinity filtration strategy facilitates clinical application of tumor-cell-based liquid biopsy.

Filtration by the fibrous medias is recognized as one of the most effective methods to control particulate pollution. A type of 3-D mesh spacer filter (3-D filter) proposed is effective for filtrating the large particles with low pressure drop. This study described the flow characteristics of dust-containing gas within the 3-D filter by means of CFD-DEM model. The influences of air velocity, particle concentration and restitution coefficient of particle on the filtration performance as well as the particles deposition process were simulated. The results showed that the particles capturing efficiency of 3-D filter was increased with the air velocity and particle concentration while the particles rebound made the filtration efficiency decreased when the air speed was increased more than 3.0 m/s. For the particle properties, the smaller restitution coefficient, the higher filtration efficiency. When the quality of particle deposition was increased to 70 g/m2, the filtration efficiency almost remained unchanged.

Nowadays, accurate and real-time vehicle tracking is critical to ensure the safety of intelligent vehicles. However, tracking in the complex traffic environments still remains a challenging issue. In this article, we present a road-map aided Gaussian mixture probability hypothesis density (RA-GMPHD) filter for multivehicle tracking with automotive radar. Since the road-map is commonly available in traffic scenarios, we focus on leveraging road-map information to enhance the tracking performance. We first model the vehicle dynamics in a 2-D road coordinates, then approximatively map it onto ground coordinates considering map errors. Additionally, we integrate the variable structure interacting multiple model into the RA-GMPHD filter considering both the dynamic uncertainty of targets and the road geographic constraints. Furthermore, we perform extensive simulations and conduct physical testings to demonstrate the superiority of our approaches compared with state-of-the-art method. Experimental results show our methods enhance both the tracking quality and tracking continuity.

For the single-phase high-power railway traction system, the inevitable second-order resonating power has become a critical issue to the traction system. In this article, a power-decoupling solution is proposed to replace the conventional passive LC resonance filter by utilizing the buck-type bidirectional dc/dc converter (BBDC) of hybrid electric multiple units, which is designed to power the train in nonelectrified routes using the on-board battery. By considering both the current ripples in the battery mode and the power decoupling in the catenary mode, the corresponding parameter design process of the BBDC is presented. Based on the power coupling phenomenon and the spectrum characteristic of the BBDC, a direct resonance control method is proposed to decouple the low-order resonating power. Simulations and experiments are carried out to validate the effectiveness of the new proposal. The results demonstrate that the proposal is almost the same as using the conventional passive LC resonance filter for power decoupling in both steady and dynamic operation scenarios.

Combining the synthesis and crystallization of a compound into a single step may be beneficial for certain processes. Motivations range from process intensification to improving reaction network yield by shifting an equilibrium limited reaction or protecting an intermediate, as is the case in the biocatalytic synthesis of beta-lactam antibiotics. Adapting such a reactive crystallization process to continuous manufacturing faces a challenge: the continuous separation of crystals from biocatalyst carriers. In this study, a size-based method for this separation problem is proposed. Separation is performed using a filter placed on the reactive crystallization vessel outlet. The primary factors for filter design are carrier and crystal size dictated by the separation condition Lcrystal

In this paper, a high-speed switchable dual-passband microwave photonic filter (MPF) using a single mode Fabry-Perot laser diode (SMFP-LD) is proposed and experimentally demonstrated. Benefiting from the wavelength selective amplification in the SMFP-LD, the +1st sideband of two external beams injected after phase modulation can be amplified in the gain spectrum of the SMFP-LD. Hence, an MPF with two tunable passbands is generated. The switching of the generated passbands is obtained through the switching signal of 1 Gbps applied to the modulator, which controls the power of one of the external beams. By properly setting the external beams injection parameters, the passbands of MPF can switch from single passband to no passband, single passband to dual passband, and one passband to another passband. In this experiment, the maximum center frequency and tuning range of the passbands is 45.0 GHz and 35.0 GHz, respectively. The out-of-band rejection ratio and 3 dB bandwidth of the proposed filter are 29.62 dB and 83 MHz, respectively.

This work, for the first time, presents an absorptive frequency-tunable substrate-integrated waveguide (SIW) filter. For the filter design, an absorptive bandpass filter prototype tailored to an SIW structure has been formulated. The proposed absorptive bandpass filter prototype is capable of having a return loss larger than 20 dB at all frequencies although it has a simple matching circuit. The filter prototype has been attained by comprehensive formula-based synthesis of a new matching circuit equivalent to an existing one. To validate our filter prototype, a second-order absorptive bandpass filter that can alter its center frequency has been designed, fabricated, and measured. This article demonstrates approaches to find physical dimensions by comparing each section of the filter structure with the corresponding part of the prototype. The fabricated absorptive bandpass filter has a compact structure by virtue of its simple matching section. The frequency-tunable SIW resonators allow our absorptive bandpass filter to adjust its center frequency from 1.76 to 2.69 GHz while having absorptive performance. The measured reflection of the filter centered at 2.50 GHz is smaller than -10 dB between 1.56 and 3.27 GHz (2.10:1). It is shown that theory, simulation results, and measured responses are in good agreement.

This work presents the design of an additively manufactured W-band bandpass filter and a subtractively manufactured W-band diplexer in order to demonstrate the use of admittance inverter sequences for the ease of manufacture at millimetre-wave frequencies. Contrary to typical impedance inverters (E-plane and H-plane irises), the use of admittance inverters (E-plane and H-plane stubs) allow for larger dimensions to be specified and ultimately do not impede the general waveguide path. The proposed bandpass filter is designed with all E-plane stubs, while the diplexer is designed with one branch utilizing both E-plane and H-plane stubs as an arbitrary sequence, and the second branch utilizing all H-plane irises. The additively manufactured bandpass filter is fabricated using the most elementary level stereolithography (SLA) based methods, demonstrating that a hobbyist-type SLA printer and metallization method can procure exceptional results for millimeter-wave filter designs. The subtractively manufactured diplexer is fabricated using high-precision computer numerical control (CNC) milling in order to highlight the use of arbitrary inverter sequences in a more complex and robust design profile, while the dispersive transmission zeros that are caused by over-moding of the inverter stubs is utilized to demonstrate unique isolation characteristics in the upper W-band region. The design concepts, fabrication profiles, simulations and measurements which are presented in this work highlight a viable option for overcoming miniaturized dimensions in millimetre and sub-millimetre-wave applications.

This is a knowledge contribution to the unsatisfactory biodegradation problem, when biotrickling filters are purifying mixed paint solvents. A biotrickling filter manufacturer reported low biodegradation rates during the purification of a hydrocarbon pollutant mix from an industrial paint spraying floor. From a gas chromatograph/mass spectrometer analysis both hydrophilic and hydrophobic solvents were found in the polluted air. It is known that biodegradation is retarded, if the pollutant does not transfer from gas to liquid into the biofilm and it was therefore suspected that hydrophobic pollutants do not sufficiently migrate into the water/biofilm. To test this hypothesis, pure, rather than mixed pollutants, were injected into the abiotic biotrickling filter. When hydrophobic paint solvent (xylene) was sprayed into the biotrickling filter, the solvent load at the outlet of the filter was almost as high as at the inlet. But when pure, hydrophilic paint solvent (PGME) was sprayed into the abiotic biotrickling filter, the solvent load measured at the outlet of the filter was zero, indicating complete dissolution into the circulation water. Carbon/solvent loads at the filter outlet and inlet were measured with a portable flame ionization detector instrument. The experiment confirms that the hydrophobic solvent does not migrate into the liquid phase. This poor mass transfer of hydrophobic solvents is likely to be the reason for the low biodegradation rate. The result is highly relevant to the paint spraying industry and manufacturers of exhaust gas treatment equipment alike, who spend millions in non-sustainable incineration of exhaust gases.

This paper presents a new mutually coupled circuit (MCC) based on voltage differencing current conveyor (VDCC). The proposed MCC has been designed using the Gorski-Popiel technique. The proposed circuit consists of two VDCCs as active elements, three resistors, and two grounded capacitors as passive elements. The primary and secondary self-inductances and the mutual inductance can be controlled independently and can be adjusted electronically by the bias current of the VDCCs. There is only one matching condition for satisfying symmetrical coupling. Time and frequency-domain analyses have been performed with the LTspice program to verify the theoretical analyses. A double-tuned band-pass filter application is given to show the functionality of the proposed MCC.

In this paper, Sensorless Permanent Magnet Synchronous Motor (PMSM) using Extended Kalman Filter (EKF) is presented. The previous PMSM drive uses a sensor to measure the motor’s speed. Then the idea is to replace the sensor by using sensorless drives based on the observer. For the conventional observer, it’s only good for low current and low-speed applications. Moreover, it is hard to detect the phase voltage due to the non-existence of neutral wire. Therefore, this project proposes sensorless control using an EKF. This method provides an optional estimation algorithm for the non-linear system that can produce a fast and accurate estimation of state variables. The accurate estimation will reduce the noise and ripple of the system. Additionally, the EKF do not require the information of mechanical parameters and the initial position of the rotor, making the construction is easy and simple. In this paper, the fundamental of the EKF algorithm is explained and the simulation results for different speeds and loads are presented. The noise reduction test is also conducted to measure the flux current with and without the filter. The simulation study is achieved using MATLAB/Simulink to verify the effectiveness of the proposed method. The results of the simulation show that the sensorless PMSM drives using EKF have lower overshoot and faster rise time during start-up conditions and have lower undershoot during the loaded condition. It also can be concluded that the proposed sensorless PMSM drive using EKF has good speed control accuracy and can reduce the current noise.

A positioning system estimates the position and orientation of a vehicle. Autonomous driving systems plan paths and control the vehicle based on the information from the positioning system. Recently, methods of estimating the position in urban areas have been actively studied. In U-turn sections, which are common in urban areas, vehicles perform a rotation to reverse the direction of travel. Through these sections, drivers can reduce the travel distance and save time but with a high risk of an accident. Despite there being a need for the development of autonomous driving schemes for U-turn sections, the existing research is limited. This study proposes an interacting multiple model (IMM) filter-based position estimation algorithm for urban U-turn sections. To reflect the dynamic characteristics of a vehicle during U-turn maneuvers, a multiple vehicle model was used. This model includes kinematic and dynamic vehicle models. The state estimates of the vehicle model and gyroscope are combined using an IMM filter. The position estimation algorithm developed in this study is verified via experiments. The experimental results indicate that, during urban U-turn maneuvers, the position estimation accuracy of the IMM filter-based algorithm is improved than that of the single vehicle model.

Acoustic manipulation is a non-contact process that applies acoustic waves to immobilize particles into a specific region for a variety of potential applications. This provides an alternative way to address air ventilation requirements where building systems are becoming smarter and more efficient. Development of such a process within confined spaces can incorporate microscopic interactions to filter aerosol-based particulate matter (PM). In real-engineering conditions, it is hard to filter sub-micron particles (0.25–1.0 μm) than super-micron particles (> 2.5 μm) by using low-grade filters. The objectives of this work are twofold. First, we propose a new acoustic-driven pre-filtering device (i.e., a U-shaped resonant acoustic chamber) that can improve the working efficiency of low-grade filters for capturing such particles. Second, the device can optimize spatial homogeneity to enhance the removal efficiency of airborne particles under lower sound intensity requirements. The U-shaped acoustic-driven device in the form of a resonant chamber allows PM to reside at the pressure node of a standing wave. Experimental studies are conducted to verify the present design. The results show that an overall filtration efficiency of up to 89% for 1.0-μm airborne particles can be achieved when the acoustic-driven device is coupled together with a low-grade MERV-6 coarse filter. As a standalone device, the acoustic effect works well for the sub-micron particles with a filtration efficiency of up to 61% under a lower sound pressure level (116 dB) than as previously reported in the literature. In the analysis, we also discuss the performance dependence on frequency, sound pressure level and flow rate in terms of particle size distribution. The relevance of this research is a major step towards engineering an acoustic-based pre-filtering technique for developing future innovative ventilation solutions.

This letter presents an eighth-order dual-mode waveguide filter, fabricated using the selective laser melting (SLM) technique. The filter employs four dimpled ellipsoid dual-mode resonators, operating at the fundamental TM101 mode. During printing, the filter can be mechanically self-supported without any internal supports. Compared to the filters employing tuning posts, the proposed filter is less sensitive to fabrication errors in terms of their impacts on passband return loss (RL), frequency shift, and bandwidth. The filter was demonstrated at WR-112 band (7–10 GHz), with a measured insertion loss of 0.25–0.4 dB and an RL >15 dB across the passband of 8–8.46 GHz.

This letter presents our study on a compact and low-loss E-band bandpass filter (BPF) based on multilayer groove gap waveguide (GGW). Different from other reported planar GGW filters and vertically stacked substrate integrated waveguide (SIW) filters, the proposed filter realizes a cross-coupled quadruplet topology by introducing a pair of unique circular capacitive holes across layers, innovative ridges (capacitive iris), and conventional inductive irises on the same layer, which reduces the insertion loss (IL) while having a smaller size. By tuning the dimensions of the coupling structures and cavities, the filter is optimized to exhibit a superior performance in simulation. The designed filter is fabricated using CNC machining and verified in experiment. The measured results agree with the simulated ones quite well, showing an average IL of 0.45 dB and an 8% relative 3-dB bandwidth at a center frequency of 73.65 GHz. Therefore, the proposed multilayer GGW structure opens a new avenue in designing high-performance filters in millimeter-wave bands.

A three-phase three-level converter with an LCL filter has been used in the industry because of its low switching harmonics. However, it inevitably suffers from dc neutral-point imbalance, which may unnecessarily stress semiconductors and deteriorate power quality. The imbalance will, nevertheless, naturally rebalance, but it usually takes a long time. A common rectification is, thus, to add an active or a passive booster to speed up the balancing. An active booster requires sensitive sensors and control modification, which will increase the system cost and complexity. A passive booster is, therefore, preferred owing to its exemption of monitoring and control efforts. The existing three-phase passive booster, however, contains several extra separate LC components, which are normally not functioning during the balanced conditions. They should, hence, be reduced. One approach is to dual use the existing LCL (or other high-order) filter for both harmonic filtering and dc-link balancing. Topologically, it requires only the addition of one extra capacitor along the return common-mode path. Using newly formulated criterions related to sizing, harmonic, and modulation selections, the balancing performance of the resulting capacitive balancer has been evaluated comprehensively. Finally, an experimental prototype is built for testing the balancing mechanism under different operating conditions.

This letter describes the design of a right-hand circularly polarized planar filtenna (filter + antenna) that can reconfigure its operation between two center frequencies in the Ka-band. The filtenna structure is composed of a four-element array radiator and a reconfigurable bandpass filter, occupying an area of 31 × 14 mm. The circularly polarized array elements are fed by a sequential power divider for an enhanced polarization purity. The filter is based on a ring resonator loaded with a variable open stub. The length of the stub extends through a p-i-n diode switch, resulting in a change of the loaded reactance into the ring, and consequently tuning the filter's operating center frequency from 30.3 to 29 GHz. The proposed low-loss filtenna structure exhibits a reconfigurable fractional bandwidth up to 7.74%, a peak realized gain that can reach up to 11.5 dBic, an axial ratio of less than 1 dB, and a sidelobe level that can go as low as −12 dB. The prototype filtenna is fabricated and tested, where the measured results verify the simulated data. A figure of merit is proposed to highlight the superior performance of the presented Ka-band structure in terms of the polarization, size, reconfiguration ability, and radiation characteristics as proven by the comparison with other works in the literature.

We present a nonlinear geometric approach to fault detection and isolation (FDI) in a grid-connected inverter system. Open-switch faults in inverter power transistors together with faults in grid voltages and source current sensors are detected and isolated in the presence of disturbance. The detection process is based on dynamic model of an inverter, including a dc-bus capacitor and an output $RL$ filter. The proposed FDI system does not rely on balanced or zero-sum conditions in the grid point and is functional under nonsinusoidal voltages and currents.

In this paper, the problem of joint transmit waveform and receive filter design for dual-function radar-communication (DFRC) systems is studied. The considered system model involves a multiple antenna base station (BS) of a cellular system serving multiple single antenna users on the downlink. Furthermore, the BS simultaneously introduces sensing capabilities in the form of point-like target detection from the reflected return signals in a signal-dependent interference environment. A novel framework based on constrained optimization problems is proposed for the joint design of the transmit waveform and the radar receive filter such that different constraints related to the power amplifiers and the radar waveform are satisfied. In contrast to the existing approaches in the DFRC systems' literature, the proposed approach does not require the knowledge of a predetermined radar beampattern in order to optimize the performance of the radar part through its approximation. Instead, a beampattern is generated by maximizing the radar receive signal-to-interference ratio (SINR) thus, enabling a more flexible design. Moreover, the radar receive filter processing and its optimization is considered for the first time on DFRC systems, enabling the effective exploitation of the available degrees of freedom in the radar receive array. Efficient algorithmic solutions with guaranteed convergence are developed for the defined constrained nonconvex optimization problems. The effectiveness of the proposed solutions is verified via numerical results.

This article proposes an active electromagnetic interference (EMI) filter (AEF) realized by a customized integrated circuit (IC) to reduce conducted emission noises. A fully transformer-isolated feedforward current-sense current-compensation structure is selected as a base topology of the AEF. To achieve the high reliability of the proposed AEF by using low-voltage IC devices, the injection transformer is added to protect IC devices from high-voltage hazards. The operation of the proposed AEF is theoretically demonstrated, and practical design guidelines for the IC part and nearby components are developed. The designed IC was fabricated by a 0.18 μ m bipolar-CMOS-DMOS process. The fabricated IC is implemented in a compact printed circuit board for application to a three-phase inverter motor system. The performance, stability, and surge immunity of the AEF are experimentally demonstrated. A designed 1stage AEF achieves better noise-attenuation performance than 2stage passive EMI filters (PEFs) over 6 dB at 150 kHz without critical resonance peak at the high-frequency range. Weak points of the conventional PEFs in both low and high frequencies are effectively improved by using the proposed 1stage AEF. In addition, the surge immunity of the designed IC within the AEF is validated under numerous 5 kV surge tests.

To make a better discrimination between target and false alarm, amplitude information (AI) of radar signal has been incorporated into many target tracking algorithms, such as probabilistic data association, multiple hypothesis tracking and probability density hypothesis (PHD). In this paper, we present the cubature integration based Gaussian mixture implementation of the PHD filter with AI, namely the GMPHD-AI filter. Since the utilization of multiple sensors is more effective than using only one sensor, we also extend the GMPHD-AI filter to the multi-sensor application where the iterated-corrector scheme is exploited for multi-sensor information fusion. The effectiveness of the presented method is demonstrated by a multiple targets tracking scenario.

The objective of the current study is to numerically predict the collection efficiency, particulate matter (PM) loading, pressure drop, and flow characteristics in partially damaged or unplugged filters. Five different PM size classes with mean particle diameters ranging from 25 to 300 nm are considered for loading the filter. These PM classes are transported in the computational domain as scalars and collected in the filter through Brownian diffusion and interception mechanisms. Four different partially damaged filters with varying damaged cross-sections in the outlet face of the filter are considered. Five different exhaust gas flow rates from 50 to 300 kg/h with a transient soot loading condition are considered, which leads to different temporal and spatial soot cake evolutions as well as a different total soot mass in the filter. As expected, plugged filter sections have higher filtration efficiencies which increases monotonically with soot accumulation. For damaged segment, however, efficiency is nonmonotonic and depends strongly on particle size, loading, and prevailing flow conditions. The collection efficiency of damaged segments is less than 40% at all flow rates and damaged cross-sections considered in this study. The overall filter efficiency is evaluated as the sum of flow averaged filtration efficiencies of both plugged and unplugged sections. The overall filter efficiency is less than 100% and this efficiency decreases from filter-1 to filter-4 as the damaged filter section contributes to the efficiency loss. Spatial and temporal evolution of soot cake is different in damaged and undamaged sections. Strong nonuniform soot distribution is observed in the partially damaged filters in both the axial and radial direction. One objective of the current study is to analyze the overall filter collection efficiency with respect to the percentage of damage, which as a result will assist in the roadworthiness studies, on-board diagnostic studies, or periodic technical inspection of the filters or damaged filters.

This paper proposed a 5.6 kW 11.7 kW/kg four-phase interleaved buck converter (FPIBC) for the unmanned aerial vehicle (UAV) low-voltage power system. The UAV mainly concerns the lightweight strategy and the power density of the DC-DC converter. We proposed a comprehensive lightweight strategy with the characteristics of reduced inductor current ripples, small size of filter inductors and capacitors, and high output power. The output current ripples are reduced by using interleaved modulation strategy and integrated CLC filters cascaded to the input side and output side respectively. In addition, the aluminum based printed circuit board (PCB) is used with SMD power transistors to obtain better heat dissipation capability without fans. With abovementioned methods, the designed DC-DC converter has a power of 5.6 kW @ 0.48 kg, the power-to-weight ratio is improved to be 11.7 kW/kg, and the power density is 3 W/cm3. The efficiency of this DC-DC converter is up to 95.8%.

Sensorless contact force estimation methods facilitate the application of the serial manipulators to manufacturing as they enable robots to interact with unexpected collisions at low cost. In this paper, an external force estimation approach with no embedded sensors is proposed. The approach combines a Weighted Moving Average (WMA) with variable span, the standard Kalman filter (SKF), and its tuning routines. Improved confidence in the motor output torque is achieved due to the reduction of the measurement noise in the motor current by the WMA. The span of the filter adapts continuously to achieve optimal tradeoff between response time and precision of estimation in real time. With the comprehensive information of uncertainty in motor current noise and measurement errors of individual joints speed, an automatic tuning algorithm of the SKF is presented. Validation of the presented estimation approach in terms of estimation accuracy and response time was conducted on the Universal Robot 5 manipulator with differing end effector loads. It was found that the combined force estimation method leads to a reduction of the root-mean-square error and response time by 55.2% and 20.8% in comparison with the established method. The proposed method can be applied to any robotic manipulators as long as the motor information (current, joint position, and joint velocities) is available. Consequently, the cost of collision recognition could be reduced dramatically.

The purpose of this study was to determine the most efficient airborne asbestos filter for use in an HEPA negative air machines through filter performance testing. The filter classes applied conformed with ISO and European standard (EN 1822) regarding fractional efficiency by dust loading amount for filters, fractional efficiency for negative air machines, and consumption of electrical power at filter size 0.3 μm. Class H13 had the highest fractional efficiency among the three experimental filter classes by particle size, at face velocity of (1, 2, and 3) m/s. Melt-blown (MB) filters exhibited higher fractional performance than did glass-fiber filters at all particle sizes tested (0.3, 0.5, and 1.0 µm). The power consumption of glass-fiber filters was higher (at 10 m3/min) than that of melt-blown filters. Therefore, melt blown filters would be more cost-effective than glass fiber filters for use in HEPA negative air machines, for protection against airborne asbestos.Implications: Air cleaner and related systems were developed to control a variety of airborne pollutants in general indoor environments, but there was no certified system for focusing on asbestos fractional efficiency using filter tests. Class H13 had the highest fractional efficiency among the three experimental filter classes by particle size, at face velocity of (1, 2, and 3) m/s. Melt-blown filters exhibited higher fractional performance than did glass-fiber filters at all particle sizes tested (0.3, 0.5, and 1.0 µm). The power consumption of glass-fiber filters was higher (at 10 m3/min) than that of melt-blown filters.

To solve the problem of difficulty in dust removal from single-filter cartridge dust collector equipment in confined space, an orthogonal experimental design and numerical simulation methods were adopted to optimize the ash-cleaning device. The study found that the diameter of the cone base has a greater impact on the pulse cleaning performance of the dust collector than the angle of the cone, and the installation height L has the least impact. When the optimal parameters θ = 55°, D = 80 mm, L = 0 mm, compared with the traditional dust collector, the average dust concentration at the outlet of the equipment is reduced by 11.5%, the number of cleanings is reduced by 37.5%, and the pressure at the lower part of the filter cartridge is reduced. 34.7%, the upper part increased by about 53.9%. The problem of uneven cleaning of filter cartridges in confined spaces is solved, and equipment performance is improved.

In this paper, a switchable bandstop to allpass filter using cascaded transmission line SIW resonators is proposed. The switchable filter is performed by the switchable cascaded transmission line SIW resonators using discrete PIN diodes. Therefore, it can be used for rejecting any unwanted frequencies in the communication systems. The proposed filter design is operated in K-band and targeted for millimeter wave front end system for 5G telecommunication. Two filter designs with different orientation (design A and B) are investigated for the best performance and compact size. As a result, design B is the best by giving a maximum attenuation of 39.5 dB at 26.4 GHz with the layout size of 33×30 mm.

The parallel-hybrid converter (PHC) is a promising high-power topology. Smaller capacitor size, lower capacitor and switch counts, and low-energy storage requirement are some of its important features. However, it requires a large dc-filter inductor to filter the dc-side harmonics. Moreover, since its dc and ac sides are strongly coupled, only a single stable operating point in terms of a fixed modulation-index (MI) value is possible. Even with an additional dedicated control effort, the obtained MI variation remains still limited. This article proposes the PHC-static compensator (STATCOM) configuration that eliminates the dc-filter inductor requirement and can also operate at any MI value without necessitating additional control efforts. A detailed power analysis of the PHC-STATCOM for balanced and unbalanced grid conditions (UGCs) is performed in this article. A new control technique for PHC-STATCOM is proposed, which effectively balances the capacitor voltages of its chain-links even during UGCs. The energy storage requirement of PHC-STATCOM is evaluated to obtain the capability curve and determine its capacitor size. The PHC-STATCOM is compared with the popular STATCOM configurations in terms of the capacitor and switch counts. The proposed principles of PHC-STATCOM for several three-phase balanced and UGCs are verified using simulation and experimental studies.

Bi-directional optogenetics at single-cell level requires localized, bright, and multi-color light sources to activate both excitatory and inhibitory opsins. To this end, here we report a simple fabrication method of high-density, two-color, quantum dot (QD) based micron-sized light emitting diode (micro-LED) arrays. In particular, we micro-patterned InP/ZnS QDs on top of GaN-based micro-LED pixels via a simple brushing method, and coated them with a spectral filter. The resulting array featured sub- $20~\mu \text{m}$ sized light spots near both 462 nm and 623 nm, with their optical power density being ca. 0.1 – 1.0 mW/mm2. Combined with its low crosstalk and fast response, our two-color QD-LED array may hold promise for bi-directional optogenetics ultimately at the cellular level.

The recent trends show the interconnection of PV system with electric grid. With this configuration the issue of harmonics comes into existence. The mounting figure of power-electronic instruments has formed considerable impression on the power-quality of electric supply. Harmonics deformations have conventionally been handled amid the application of passive-LC filters. Active Filter has emerged as a good substitute for passive filters to reduce the harmonics to great extent as it has numerous benefits over the former filters. The active filter’s most vital part is the applied control strategies. Several researches are being under process to advance the functioning of the filter. One of the important control requirements of filter is the regulation of DC link up capacitor voltage. Here the voltage supervision of capacitor is being done using PI controller. The paper show current harmonics compensation of PV grid connected system using PI controller based active filter. Simulation outcomes have been shown which displays the harmonics are within the IEEE boundaries.