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In this article, a reinforcement learning (RL) based controller is proposed for a multirotor-based transportation system, guaranteeing that the trained RL controller is effective in both simulation and practical experiments. The main novelty lies in that, as far as we know, this is the first attempt of combining the advantages of nonlinear and intelligent control techniques to derive a practice-oriented RL controller for the multirotor-based transportation system, where the high-dimensional complicated dynamics are fully considered in the framework. Specifically, inspired by the physical insight of the system, a new nonlinear control approach is proposed, in which the underactuated properties and the nontrivial couplings are well handled. On this basis, a RL network is proposed to parameterize the nonlinear controller, where the obtained algorithm presents the features of strong reliability and fast convergence even in complicated working conditions (e.g., model uncertainties, parameters drift, external disturbances, and so on). Subsequently, the states are proven to asymptotically converge to the equilibrium point by Lyapunov analysis and RL techniques. A series of simulation and real world experiments are implemented to verify satisfactory positioning accuracy and robustness of the proposed algorithm.

The article is devoted to the study of modeling an electrical circuit. Using the capabilities of Matlab/Simulink, circuit models are compiled for various connections and the time characteristics of the main parameters are obtained.

We apply probability theory for the analysis of the exponentially decaying transient response of a resistor inductor electric circuit with partially known value of the inductance due to its failure. The inductance is known to be within a continuous interval, and the exact value is unknown, which may happen as a result of inductor faults due to a variety of factors—for example, when the circuit is deployed in an unusually harsh environment. We consider the inductance as a continuous uniform random variable for our analysis, and the transient voltage is treated as a derived random variable which is a function of the inductance random variable. Using this approach, a probability model of the transient voltage at the output terminals of the circuit is derived in terms of its cumulative distribution function and the probability density function. In our work, we further elaborate that the probability model of any other circuit parameter can also be obtained in a similar manner, or it can be derived from the transient voltage probability model. This is demonstrated by getting the model of a branch current from the probability distribution of the transient voltage. Usage of the probability model is demonstrated with the help of examples. The probability of the transient voltage falling in a certain interval at a given instant of time is evaluated. Similarly, the probability values of the branch current in different intervals are determined and analyzed. The derived probability model is checked for its validity and correctness as well. The model is found to be useful for probabilistic analysis of the circuit.

In this paper, the general model for an infinite LC ladder network using Fibonacci wave functions that were applied to lossless transmission lines will be extended to transmission lines including losses. The general model that was derived from a first order system transfer function representing a simple RC or RL circuit will be used to model and analyze transmission lines presenting losses. The LC ladder network model can be applied to any order for each inductor current with its parasitic rc resistor and for each capacitor voltage with its parasitic rL resistor. The extension of the proposed general model to transmission lines with losses is subject to Heaviside condition for both resistors rc and rL .

The brushless excitation structure characteristics of the aviation wound-rotor synchronous starter/generator (WRSSG) put forward the requirement on the brushless exciter (BE) model that both the stator and rotor windings can be interfaced with the external circuit directly. In this paper, a double-side variable-parameter voltage-behind-reactance (DS-VP-VBR) model of the BE considering magnetic saturation was established firstly to realize the direct connection between the stator and rotor windings with external circuits. Then, a double-side constant-parameter VBR (DS-CP-VBR) model with completely decoupled RL circuit was developed through the algebraic transformation and numerical approximation from the DS-VP-VBR model. In order to further improve the model accuracy, the leakage inductance variation of the stator and rotor windings were also considered. Computer studies under steady-state and transient operating conditions verified the validity and accuracy of the proposed BE DS-VBR models.

Two types of constitutive equations consisting of instantaneous and power type hereditary contributions are proposed in order to model generalized capacitor (inductor). The first one, that expresses charge (magnetic flux) in terms of voltage (current) memory, proved to describe a dissipative electric element, while the second one, that expresses voltage (current) in terms of charge (magnetic flux) memory, proved to describe a generative electric element. These constitutive models are used in transient and steady state regime analysis of the series RC and RL circuits subject to electromotive force, as well as in the study of circuits’ frequency characteristics including their asymptotic behavior.

Multiwalled carbon nanotubes (MWNT) were deposited via dropcasting and dried using vacuum filtration. Because of the slightly larger pore size (5–10 µm) of the paper substrate used as compared to the length of the nanotubes (0.5–2 µm), a variety of MWNT networks were formed both on the surface and through the thickness of the paper. Using a combination of impedance spectroscopy, equivalent circuit modeling, and microscopy techniques, it was possible to describe in detail how the electrical properties change as a function of how the MWNTs are distributed on the porous substrate by varying the number of deposited layers (1–20) as well as the dispersion concentration (0.1–5 mg/mL). In the in-plane, four different electrical responses were observed and modeled: (1) a substrate dominated spectrum representing unconnected MWNTs, (2) one that included bundle and junction responses as well as some inductances representing sparsely distributed MWNT networks, (3) followed by a parallel RL circuit for partially connected MWNT networks, and (4) finally a series RL circuit for fully connected MWNT networks. In the thru-plane, only two different electrical responses were observed and modeled. The results for the in-plane and thru-plane properties were used to generate percolation curves that show that electrical conductivity can change as much as 10 orders of magnitude for the same exact MWNTs. These results indicate that not only do the characteristics of the nanotubes themselves play a role but also the structure of the underlying substrate and the details of how the films are deposited.

Existing converter models are normally reduced as simplified electrical components, whereas it overlooks the impacts of fast dynamics of converter current control loops. Therefore, the dc fault current calculation with the traditional simplified converter models becomes invalid when the simulation time is longer. To overcome this problem, this article incorporates the control effects of converters during the transient process and proposes three dc fault analysis models of classical three converter topologies for the high-voltage dc (HVdc) application including line communicated converter (LCC), two-level voltage-source converter (VSC), and modular multilevel converter (MMC). For an LCC-based rectifier, the nonlinear part of original model is first linearized with the least square method due to the large dc-link voltage deviation during dc fault, and the proportional integral (PI) current regulator with the reduced linearized model can be equivalent as an RC circuit for dc fault analysis. However, for two-level VSC or MMC, the dc-link voltage deviation does not drop that much with a large dc-link capacitor discharging process during transient dynamics. As a result, the original model is linearized relying on the small-signal method based on prefault operation points, and the dynamics of fast inner current loop with the linearized model can be represented as an RL circuit for dc fault current calculation. for dc fault analysis The proposed dc fault analysis models of three converters as equivalent RLC circuits are well testified under different fault resistances and dc reactors, control parameters, and operating conditions. Moreover, dc fault simulations of a hybrid HVdc system have verified the effectiveness of the proposed converter models.

The scaling trends of monolithic 3-D (M3-D) complementary metal–oxide–semiconductor (CMOS) nanoelectromechanical (NEM) reconfigurable logic (RL) circuits are compared with CMOS-only circuits for the first time. It is confirmed that M3-D CMOS-NEM RL circuits are superior to CMOS-only circuits in terms of propagation delay, power consumption, and power-delay product (PDP) because of the low resistance and full signal swing of NEM memory switches that not only affect the current switch block but also the following block. Because the performance, power, and energy gains of the CMOS-NEM RL circuits over CMOS-only circuits increase as the technology node improves, M3-D CMOS-NEM RL circuits can be considered as one of the most promising candidates for high-density, high-performance, and low-power RL circuits.

A simple control strategy of the three-phase shunt active power filter that is connected to a non-linear load network is proposed. The filter consists of a three-phase voltage source inverter based on fully controlled switches, capacitor storage, and a first-order three-phase RL filter. The decomposition of the object of study according to the rates of motion of the dynamic system was performed. The fast subsystem is a circuit of compensation current control, the slow subsystem performs stabilization of the capacitor voltage. The basis of this approach is the separation of the vector of state variables into groups of components and their consistent use as control actions. To stabilize the DC voltage on the storage capacitor, a double twisting algorithm, which is based on the forced introduction of a one-dimensional second order sliding mode is used. The proposed strategy provides asymptotic stability in the error metric of the second-order sliding mode . The output signal of the voltage stabilization subsystem is a component of the reference signal for the current tracking circuit. A low pass filter to separate the subsystems is used. Compensation current is forming by the forced entering the first-order sliding mode. To reduce the number of current sensors in the system, an indirect control strategy is used. To generate the compensation current, a two-dimensional sliding manifold, which is a linear combination of components of two-dimensional vectors - the current error of the RL filter and some variable is used. The form of this variable is determined on the assumption that the first-order sliding mode in the current loop already exists and is ideal. Each component of this sliding surface is a linear combination of components of two-dimensional vectors. The first vector is the current error of the RL filter, the coordinates of the second are locally equivalent to the derivative of fundamental harmonic of this error. A simulation model is built and the simulation results are analyzed. The proposed strategy is compared with the traditional PI-regulation on the criteria of the duration of the transient process and the coefficient of harmonic distortion in the current consumed from the grid.

The overall system stability of interconnected electrical and electronic systems is associated with the input and output impedances of each individual system, therefore, accurate AC impedance measurement for a linear and nonlinear systems are imperative. These impedances are normally measured using small-signal frequency injection techniques. However, the harmonic transfers from the output side to the input side and vice versa deteriorates the measured results, making them ambiguous. These harmonic transfers cause the problems of frequency aliasing as well as spectral leakages leading to inaccurate measurements of results. In order to achieve the precise and accurate results, there is a need to adopt such an impedance measuring technique which is the best among the available techniques. A new algorithm is proposed to modify the range of frequencies of interest and inject such small-signal frequencies which do not interfere with the system harmonics. The measurement of the AC impedance of the three-phase RL circuit utilizing three different small-signal injection techniques is performed. From the results displayed, it is clear that all the techniques perform well, therefore, the most simple, single phase line-current injection was selected for the AC impedance measurement of the nonlinear switching circuit such as six-pulse rectifier. The issues discussed above are more serious in nonlinear switching circuit because of the presence of higher order switching harmonics in the circuit. The proposed algorithm is applied to measure the output-impedance of the three-phase AC power supply as well as the AC input-impedance of the six-pulse rectifier. These results of the switch vs average model and that of average model vs. experimental prototype are displayed for comparison, and it is clear that the proposed algorithm offers much-improved results.

Low critical temperature superconducting coils can conduct persistent currents with almost no losses, as the technique to make joints is well developed and the resistive losses are negligible. The replacement of these superconductors by high-temperature superconductors may greatly reduce refrigeration costs. However, even though the technique for making these joints has greatly developed over the last years, there are still inherent difficulties associated to that process. Coils made with partially slit loops of high temperature superconducting tape have no joints, and therefore can conduct current in persistent mode. Since there are no terminals, its current must be induced through magnetization techniques, for instance, by the means of a transformer. The occurrence of persistent current is related to the voltage in the sample, making it interesting to study the voltage behavior for different regions of operation. In this work, a jointless 2G loop was magnetized with pulse magnetization from which the curves of voltage and current as functions of time were obtained. After several tests, it was possible to divide the superconductor behavior into three different stages of operation, depending on the current levels reached: for low current values, the material behaves as a perfect inductor; for current values near the critical current, it behaves as an RL circuit; and for higher values, resistance dependent on the temperature has to be taken into account. A direct relation between persistent current and the arise of a dissipative state was noted and the highest values of persistent current were observed when the pulse was intense enough to produce significant temperature variations in the sample.

Monolithic-three-dimensional (M3D) CMOS-nanoelectromechanical (CMOS-NEM) hybrid reconfigurable logic (RL) circuits are compared and analyzed with CMOS-only RL ones in the 130-nm CMOS technology node. M3D CMOS-NEM hybrid RL circuits are superior to CMOS-only ones in terms of power consumption and signal transfer speed thanks to the NEM memory switches. As well as in the routing part, it has many advantages in the logic part following the switch.

Contribution: A didactic methodology, based on analytical expressions and experimental validation, to describe the process of abrupt current interruption in a series RL circuit, that considers real passive components and uses a toggle switch as disconnecting device. Background: In undergraduate courses, circuits adopted in transient analysis usually assume electrical switches in their ideal form, disregarding electrical impedance and its variation over time. Texts and instructors rarely point out these simplifications, so students can become confused. There is thus a need for a suitable switch model that yields a behavior consistent with real devices, while permitting a mathematical formulation of the inductor current. Intended Outcomes: That students should understand electrical component modeling, and how models can represent the physical phenomena that occur in electrical circuits. Application Design: An experiment, designed to evaluate students’ perceptions of switch modeling, modeled a switch by using three different equivalent circuits of increasing complexity, to allow a more realistic simulation. Electrical switch modeling is described, with the models being based on measurements performed on a real circuit. Findings: Student performance was evaluated qualitatively through test scores, and quantitatively through a post-class questionnaire. The results indicate that 96.15% of the students were able to propose an accurate model of the electrical switch.

This paper investigates the use of resistor–inductor (RL) filters for motor overvoltage issues caused by cables connecting inverters to electric machines. Using existing filter design formulae and fixing the desired peak motor voltage, an RL filter is designed for a 15-kW industrial drive. This filter is used with a Silicon IGBT inverter and a matching between the design targets and the experimental results are found. Using the same filter with an SiC MOSFET inverter, a detrimental effect in overvoltage mitigation task is found. From simulations, it is noticed that combination of filter resistor parasitic inductance and high $dv/dt$ causes unpredicted additional high-frequency motor overvoltages. These phenomena require higher filter inductance values with respect to the standard one, thus previous filter design formulae cannot be used. New design formulae, valid when inverters with high $dv/dt$ are used, are proposed and experimentally validated. Interestingly, using the proposed formulae, it is discovered that the best filter resistance is not equal to the characteristic impedance of the cable. A design guideline that permits to optimally design the RL filter without simulation tool, considering the resistor parasitic inductance and the inverter $dv/dt$ is finally proposed.

The significant issues which are associated with grid code during grid fault are the fault ride through (FRT) capability of wind farms. This paper presents a detailed investigation of different hybrid fault ride through schemes in DFIG-based wind system under both symmetrical and unsymmetrical fault conditions. This work analyzed the performance of hybrid FRT combinations like crowbar resistance with RL circuit, DC chopper associated with crowbar resistance, DC chopper connected with series dynamic resistor, voltage control scheme with crowbar resistance are developed and studied under symmetrical and unsymmetrical fault conditions. The simulation results are obtained using MATLAB Simulink version 2019b, and the hardware real-time simulation is implemented in OPAL-RT real-time simulator. The proposed hybrid FRT schemes provide promising results improving the system parameters under different fault scenarios in grid-connected wind system.

The symmetry principle of circuit system shows that we can equate a complex structure in the circuit network to a simple circuit. Hence, this paper only considers a simple series RL circuit and first presents an uncertain RL circuit model based on multifactor uncertain differential equation by considering the external noise and internal noise in an actual electrical circuit system. Then, the solution of uncertain RL circuit equation and the inverse uncertainty distribution of solution are derived. Some applications of solution for uncertain RL circuit equation are also investigated. Finally, the method of moments is used to estimate the unknown parameters in uncertain RL circuit equation.

Half Bridge Modular Multilevel Converter (HB-MMC), a sub-module of modular multilevel converter (MMC), is widely accepted voltage source converter (VSC) topology for high voltage DC (HVDC) systems. HB-MMC has a disadvantage that it did not limit, clear DC fault current and protect IGBT converter from damage. For confining DC fault current, it is necessary to place fault current limiter (FCL) in series with HB-MMC. In this paper, Author presents two novel fault current limiter i.e. IGBT based fault current limiter (IGBT-FCL) and Parallel RL fault current limiter. IGBT based FCL consists of IGBTs and diode which are connected in parallel to each other. IGBT based FCL perform two functions i.e. it circumscribe large DC fault current and also clear DC fault current. The RL circuit has connected in series with HB-MMC. Due to no zero crossing point in DC systems, Hybrid DC circuit breaker (HDCCB) has been connected in series with Parallel RL and HB-MMC to clear the fault instantly. IGBT based FCL confine the fault current to 4 kA from 14 kA which is 72% reduction in fault current and clear fault current within 14 ms. The parallel RL circuit confines the fault current to 3.6 kA from 14 kA which shows 75% suppression of maximum DC fault current. With the help of HDCCB, the fault is cleared within 18 ms. The PSCAD/EMTDC has been used for designing of HB-MMC, IGBT-FCL, Parallel RL circuit and HDCCB.

A vector strategy for controlling a three-phase shunt active filter (SAPF), which is connected to the network with the existing nonlinear load, is proposed. The filter consists of a semiconductor voltage inverter with fully controlled switches, a capacitive storage and a single-link RL filter. The DC voltage stabilization of the capacitive storage using a second-order sliding mode, which is based on the implementation of a finite twisting algorithm is performed. A vector algorithm (the "rhombus-type") for tracking the instantaneous value of the current to generate a compensating current is used. The proposed algorithm uses the methods of projective geometry to determine the relative position of the space vectors of the voltages and the currents of the power supply system, so it does not contain difficult mathematical operations (for ex. - calculating inverse trigonometric functions). The choice of the appropriate output voltage vector of the SAPF inverter is based on the spatial location of the equivalent control vector, the coordinates of which are calculated in real time. The current tracking error sign is estimated using a quasi-stationary two-dimensional sliding surface, which is a linear combination of the components of the two-dimensional current error vector of the RL filter. A simulation model is developed and the results of simulation are analyzed. The proposed strategy is compared with the traditional hysteresis algorithm according to the criteria of the number of switchings and the coefficient of harmonic distortion in the current consumed from the network.

A simplified vector strategy for tracking the compensation current of a three-phase shunt active filter (SAPF) is proposed. SAPF consists of a semiconductor voltage inverter with fully controlled switches, a capacitive storage and a single-link RL filter. The difference in the speed of the dynamic system allows us to distinguish between a fast subsystem, in which the vector method of current control is actually used, and a slow subsystem, the function of which is to stabilize the constant voltage of the storage capacitor. The DC voltage of this capacitor is stabilized by a second-order sliding mode using a finite double-twisting algorithm. The first-order two-dimensional sliding mode is used to tracking the compensation current. The proposed algorithm uses the methods of projective geometry to unambiguously determine the mutual location of spatial vectors of voltages and errors of power supply currents. Since the algorithm does not have difficult mathematical operations for calculating inverse trigonometric functions, it is quite simple in technical implementation. The components of the space vector of equivalent control in a stationary coordinate system are calculated in real time. The choice of the desired output voltage vector of the SAPF inverter is determined by the location of the vector of equivalent control relative to the set of these stationary vectors. Estimation of signs of components of a two-dimensional vector of an error of tracking of current occurs with use of a quasi-stationary two-dimensional sliding surface. The algorithm uses the figure of permissible errors in the form of a circle with a radius equal to the desired value of the instantaneous deviation of each component of the stum from the reference value. A simulation model is built and the simulation results are analyzed.

The paper introduces the control and operation of a grid-connected converter with an energy storage system. A complete mathematical model is presented for a converter and its control. The system under study is a small microgrid comprising an AC grid that is feeding a DC load through a converter. The converter is connected to the AC grid through R-L filter. On the DC side an energy storage system ESS is connected to the DC bus. Classical linear controllers have limitations due to their slow transient performance and low robustness against parameter variations and load disturbances. In this paper, a machine learned controllers are used to deal with those drawbacks of the traditional controller. First, a study for conventional nested loop Proportional Integral for both outer and inner loops PI-PI controller is introduced. Then, a Data Driven Online Learning (DDOL) controller is proposed. This controller is a Proportional Integral Neural Network (PI-NN) that is used to enhance the system performance in terms of dynamic and steady-state responses. A comparison between the normal traditional PI-PI controller and the proposed DDOL ones is made under different operating scenarios. The converter control is tested under different operational conditions, and its dynamic and steady-state behavior is analyzed. The model is done through a MATLAB Simulink to check the normal operation of the network in a grid-connected mode under different load disturbances and AC input voltage. The results are showing that the intelligent controller can achieve the set reference points with better performance in terms of both dynamic and steady-state responses.

A simple vector strategy for controlling the compensation current of a three-phase shunt active power filter (SAPF), which is based on the forced introduction of a first-order sliding mode is proposed. SAPF consists of a semiconductor voltage inverter with fully controlled switches, a capacitive storage and a single-link RL filter. Decomposition of the object of study according to the moving rates of the dynamic system allows to distinguish a fast subsystem that implements the vector method of controlling the compensation current, and a slow subsystem, the function of which is to stabilize the constant voltage of the drive capacitor. The DC voltage stabilization of the capacitive storage is performed using a finite twisting algorithm, which belongs to the class of the second order sliding modes. The first-order two-dimensional sliding mode to generate the compensation current is used. The proposed algorithm is a vector-type algorithm and uses the methods of projective geometry to unambiguously determine the mutual location of spatial vectors of voltages and errors of power supply currents. The algorithm is quite simple to implement, because it lacks difficult mathematical operations for calculating inverse trigonometric functions. The selection of the required output voltage vector of the SAPF inverter is determined by determining the location of the spatial vector of equivalent control in a stationary coordinate system α-β, the components of which are calculated in real time. The current tracking error sign using a quasi-stationary two-dimensional sliding surface and a circle-tolerant figure is estimated. The sliding surface is a linear combination of components of the two-dimensional current error vector of the RL filter. A simulation model was built and the simulation results are analyzed.

Tri-state nanoelectromechanical (NEM) memory switches are proposed for the implementation of high-impedance state 0 in addition to low-impedance states 1 and 2 for the improvement of conventional complementary metal-oxide-semiconductor-NEM (CMOS-NEM) reconfigurable logic (RL) operations. Although it is well known that the high impedance state of routing switches is essential to prevent the unnecessary data throughput of RL circuits, previously proposed NEM memory switches have only implemented binary states: states 1 and 2. On the contrary, our proposed NEM memory switches can have tri-states, which are achieved by modifying their operation methods and design guidelines.

Residual flux density in the single-phase transformer core can dramatically increase inrush current when the transformer is energized. To reduce inrush current, it is necessary to study residual flux density measurement. This paper proposes a new residual flux density measurement method based on time constant. Firstly, the generation principle of residual flux density is analyzed under different magnetization states, and it is found that the positive relative differential permeability is smaller than the negative at different residual flux density. To obtain the relative differential permeability, when an appropriate DC excitation is applied, the measurement circuit is equivalent to a first-order RL circuit. Then, combining magnetic circuit and transient circuit analysis, the relationship between time constant and relative differential permeability is obtained. It is conclusion that the positive time constant is less than the negative. Residual flux density direction is determined by comparing the positive and negative time constant, and the magnitude of residual flux density is calculated by the relationship between residual flux density and the difference of the positive and negative time constant. Finally, the empirical formula between residual flux density and time constant difference of the square core is obtained in finite element method, and then verified on the experimental platform. Compared with other measurement methods, the relative error of proposed empirical formula is within 4.58 %, and it has higher accuracy in this paper. The proposed method in this paper can provide a reference for selecting the demagnetization voltage, which improves the effectiveness of demagnetization.

In this paper, a novel application of biologically inspired computing paradigm is presented for solving initial value problem (IVP) of electric circuits based on nonlinear RL model by exploiting the competency of accurate modeling with feed forward artificial neural network (FF-ANN), global search efficacy of genetic algorithms (GA) and rapid local search with sequential quadratic programming (SQP). The fitness function for IVP of associated nonlinear RL circuit is developed by exploiting the approximation theory in mean squared error sense using an approximate FF-ANN model. Training of the networks is conducted by integrated computational heuristic based on GA-aided with SQP, i.e., GA-SQP. The designed methodology is evaluated to variants of nonlinear RL systems based on both AC and DC excitations for number of scenarios with different voltages, resistances and inductance parameters. The comparative studies of the proposed results with Adam’s numerical solutions in terms of various performance measures verify the accuracy of the scheme. Results of statistics based on Monte-Carlo simulations validate the accuracy, convergence, stability and robustness of the designed scheme for solving problem in nonlinear circuit theory.

This paper deals with an interdisciplinary research work between Mathematical sciences and Electrical engineering to develop fractional model of Resistance-Inductance circuit (RL circuit). Authors obtained the analytical solution of this fractional model in terms of Mittag-Leffler function. Graphical interpretation of solution also discussed in this paper.

A low-power W-band gain-enhanced CMOS down-conversion mixer for millimeter-wave-to-baseband pulsed-radar receiver is presented. To enhance the equivalent load impedance while keeping the transconductance ( $\text{g}_{\mathrm {m}}$ ) of the RF $\text{g}_{\mathrm {m}}$ stage unchanged and achieving prominent IF bandwidth, we propose a novel core IF load, which is based on the parallel combination of the cross-coupled PMOS transistors (CCPT) and the series RL circuit (i.e., CCPT-RL-based core IF load). The down-conversion mixer comprises a double-balanced Gilbert-cell-based mixer core with an inductive-peaking current-bleeding RF $\text{g}_{\mathrm {m}}$ stage and a CCPT-RL-based core IF load, two elliptic baluns, and a source follower buffer. Compared with the traditional down-conversion mixer for direct conversion receiver, conversion gain (CG), and noise figure (NF) can be significantly enhanced. For 88~100 GHz, the mixer consumes 5 mW and achieves excellent RF-port input reflection coefficient ( ${S}_{11}$ ) of −9.6~−19.1 dB and LO-port input reflection coefficient ( ${S}_{22}$ ) of −5.5~−21.9 dB. In addition, the mixer achieves excellent CG of 11.8~14.6 dB, NF of 14.2~15.2 dB, and LO-RF isolation of 34.6~35.3 dB–one of the best CG, NF, and LO-RF isolation results ever reported for a W-band down-conversion mixer.

This paper presents a new robust control strategy for islanded operation of a microgrid consisting of several distributed generation (DG) units with arbitrary topology. Each DG unit is connected to its local load through a voltage-source converter, a series RL filter and a step-up transformer. The multi-DG microgrid with arbitrary connectivity graph is modeled as a linear time-invariant system subject to a parametric, norm-bounded uncertain block. By utilizing the developed model for multi-DG microgrids, a systematic approach for the design of structured dynamic output feedback control is proposed. A convex optimization problem is developed which yields a low-order dynamic controller of arbitrary structure such that the microgrid channels are all decoupled at the presence of load parameter uncertainties. Simulation case studies performed in MATLAB/SimPowerSystems Toolbox verify the performance of the proposed strategy.

Energy harvesting (EH) is a promising technique to fulfill the long-term and self-sustainable operations for Internet of Things (IoT) systems. In this paper, we study the joint access control and battery prediction problems in a small-cell IoT system including multiple EH user equipments (UEs) and one base station (BS) with limited uplink access channels. Each UE has a rechargeable battery with finite capacity. The system control is modeled as a Markov decision process without complete prior knowledge assumed at the BS, which also deals with large sizes in both state and action spaces. First, to handle the access control problem assuming causal battery and channel state information, we propose a scheduling algorithm that maximizes the uplink transmission sum rate based on reinforcement learning (RL) with deep ${Q}$ -network enhancement. Second, for the battery prediction problem, with a fixed round-robin access control policy adopted, we develop an RL-based algorithm to minimize the prediction loss (error) without any model knowledge about the energy source and energy arrival process. Finally, the joint access control and battery prediction problem is investigated, where we propose a two-layer RL network to simultaneously deal with maximizing the sum rate and minimizing the prediction loss: the first layer is for battery prediction, the second layer generates the access policy based on the output from the first layer. Experiment results show that the three proposed RL algorithms can achieve better performances compared with existing benchmarks.

A novel “slingshot” pull-in operation is proposed to lower the operation voltage ( ${V}_{\text {DD}}$ ) of nanoelectromechanical (NEM) memory switches for the implementation of monolithic 3-D (M3D) CMOS-NEM hybrid reconfigurable logic (RL) circuits. According to the theoretical calculation and experimental data, the proposed “slingshot” pull-in operation lowers ${V}_{\text {DD}}$ of the NEM memory switches by ~0.84 times. It contributes to the overall ${V}_{\text {DD}}$ reduction and chip density boost of M3D CMOS-NEM RL circuits.

This paper proposes direct microcontroller interface circuit on Arduino platform, which is realized using the inductive sensors. The circuit is composed of two external resistors and two reference inductors resulting in four RL circuits. The microcontroller independently excites the two RL circuit on the primary side in order to measure the discharging time of voltage across each inductor. The discharging time of voltage across the inductors on the secondary side is measured similarly which is excited due to mutual inductance from the primary side. The technique of time-to-digital conversion from the built-in timer of microcontroller enables estimation of inductance value, which is compared with the actual value for self-inductance and mutual inductance circuits. Error analysis on the discharge time measurement are performed viz, parasitic resistance, parasitic capacitance on input–output ports along with ringing effects and relative quantization error. The resistance and inductance estimation with regards to varying time period of oscillation of crystal is performed to analyze the effect of oscillation frequency on estimation. The parasitic resistance and quantization effects both contribute to the non-linearity errors (NLE) which is investigated further experimentally. The optimum value of the resistance was observed to be 120Ω and 60Ω for the primary and secondary side respectively. For primary side, the current and power consumption is 29 mA and 145 mW respectively, while for the secondary side, the current and power consumption is 27.5 mA and 137.5 mW respectively. The maximum NLE of −0.18 %FSS and −0.24 %FSS has been observed for an inductance range of 1 mH–10 mH along both primary and secondary sides respectively, whereas for an inductance range of 10 mH–100 mH, the NLE achieved was 0.29 %FSS and −0.34 %FSS for the primary and secondary sides respectively. The future scope of the linear position displacement of the inductive sensor concludes the paper. Keywords: Microcontroller, Arduino UNO, Mutual inductance sensor, RL circuit

Grid connected inverters constitute the most important part of any modern day micro-grid. However, for the optimal usage of the resources, it becomes a necessity to track the dynamic changes in the plant parameters. In this paper, a parameter estimation architecture is employed in a synchronous frame of reference and the controller parameters are updated online. To verify the performance of the control come estimation architecture, a deadbeat control is implemented on a three phase grid connected inverter with RL filter. The controller parameter gains are adjusted based on the parameter estimated. Verification of the proposed methodology is carried out via simulation based on MATLAB/Simulink and PLECS domain along with experimental verification on a reduced scale laboratory prototype.

In this paper, a Ku-band tunable absorptive frequency selective reflector (TAFSR) is proposed. The TAFSR has a sandwich structure: an active resistive sheet at the top layer, and PEC at the bottom layer, divided by F4B substrate. The resistive sheet layer is composed of a simple straight strip between two metallic strips with PIN diodes loaded to get the tunable reflective coefficient. PIN diodes can be equivalent to serial RL circuit. Two metallic strips and the gap between units is equivalent to serial LC circuit to control the resonant center frequency. The biased strip can be equivalent to the parallel inductance circuit as the electric structure and the biased lines simultaneously. The influence of the PIN diodes' tunable resistance is analyzed through equivalent circuit model. The measurement results show that the −10dB tunable absorptive band of the proposed TAFSR can be achieved in Ku-band from 10.3 GHz to 19.2 GHz.

we introduce a new function, which is defined by replacing polynomials withpolynomial factorials in the expansion of exponential function denoted by entitled as extorial function, an original and unique contribution. The identities that must be used with difference operators and factorials are mentioned. In the RL circuit, these identities are used to find solutions to the difference and discrete partial difference equations for heat and current flows. The above results are supported by numerical verifications. On the basis of the findings, the solution for current flow in the RL circuit is effectively derived after formulating the current flow as the discrete and fractional equations.

Generalized capacitor (inductor) is constitutively modeled by expressing charge (magnetic flux) in terms of voltage (current) memory as a sum of instantaneous and power type hereditary contributions and it is proved to be a dissipative electric element by thermodynamic analysis. On the contrary, generalized capacitor (inductor) as a generative electric element is modeled using the same form of the constitutive equation, but by expressing voltage (current) in terms of charge (magnetic flux) memory. These constitutive models are used in transient and steady state regime analysis of the series RC and RL circuits subject to electromotive force, as well as in the study of circuits' frequency characteristics including asymptotic behavior.

We demonstrate a successful navigation and docking control system for the John Deere Tango autonomous mower, using only a single camera as the input. This vision-only system is of interest because it is inexpensive, simple for production, and requires no external sensing. This is in contrast to existing systems that rely on integrated position sensors and global positioning system (GPS) technologies. To produce our system we combined a state-of-the-art object detection architecture, You Look Only Once (YOLO), with a reinforcement learning (RL) architecture, Double Deep Q-Networks (Double DQN). The object detection network identifies features on the mower and passes its output to the RL network, providing it with a low-dimensional representation that enables rapid and robust training. Finally, the RL network learns how to navigate the machine to the desired spot in a custom simulation environment. When tested on mower hardware, the system is able to dock with centimeter-level accuracy from arbitrary initial locations and orientations.

With more and more applications of DC microgrids in power systems, reasonable control methods need to be adopted so that DC microgrids can be connected to large power grids in a friendly manner. Most DC microgrids use power electronic converters to achieve grid-connected and electrical energy transmission. The access of a large number of power electronic converters has a great impact on the stability of the power system.The Virtual Synchronous Generator (VSG) solves the disadvantages of low damping and small inertia of the DC microgrid, but ignores the effects of harmonics on the grid.Firstly, the excitation regulator and power frequency regulator are analyzed to establish a mathematical model; Secondly, the network-side RL filter circuit is designed and the parameters are given. The harmonics of the network before and after the filtering are analyzed and the ideal network is realized. Finally, a simulation model is established in MATLAB, and the correctness of the proposed method is verified by simulation.

This chapter gives an insight into the class of tracking problems in nonlinear systems for which the first-order derivative of the reference function does not exist. Using classical sliding mode control, only a restricted class of reference functions can be tracked. A solution to this problem by using fractional-order operators is proposed. The technique works provided the reference function satisfies the Holder condition. Notably, its application to a switch-controlled RL circuit is demonstrated and some of the possible applications have been discussed.

Measurement of high-current pulses is crucial in some special applications, e.g., electrodynamic accelerators (EA) and converters. In such cases, the current shunts have limitations concerning the frequency bandwidth. To overcome the problem, a method based on the shunt mathematical model is proposed. In the method, the solution of ordinary differential equations for the RL circuit is carried out in order to obtain the real current shape. To check the method, as a referee, a Rogowski coil dedicated to measuring high-current pulses was used. Additionally, the measurement results were compared with the mathematical model of the tested power supply system. Measurements were made for the short power supply circuit, which allows eliminating the nonlinearity. The calculations were carried out using a circuit model. In order to obtain the parameters of the shunt (resistance and inductance), it was modeled using an ANSYS/Q3D Extractor software. Comparison of calculation and measurement results confirms the correctness of our method. In order to compare results, the normalized root mean square error (NRMSE) was used.

This work addresses the problem of negative incremental resistance behaviour that arises due to the impedance interactions between the power electronic converters that consists of an LC filter and a tightly regulated DC-DC buck converter. Failing to address this problem renders the cascaded system prone to instability. This paper introduces three different parallel virtual impedances, connected across the capacitor of the source side converter for restoring the stability and also for improving the dynamic performance of the load converter, during the external disturbances. The specific advantage of the proposed approach is that it requires the sensing of voltage across the LC filter rather than the current through the inductor in LC filter for designing the required virtual impedance. All these impedance configurations not only provide stability but also ensure a good dynamic response both across the LC filter and at the load converter's output voltage terminals. The response from the MATLAB/SIMULINK based simulations reveal the stability at steady state and the dynamic performance shows the improvement over a second order virtual impedance and an optimal method. Among the chosen impedance network configurations, the series RL network exhibits superior dynamic response to external disturbances. Analytical and simulation results of the work are included.

In this paper, the model and simulation in state space of a wind energy conversion system (WECS), using the type-4 wind turbine topology is presented. The model in state space of a wind turbine (WT) with direct-drive permanent magnet synchronous generator (PMSG) via full scale back-to-back converter integrated into the power grid using a RL filter is described. The particular interest in this work is to address the dynamic study of variable-speed wind, evaluating the performance of proposed control devices. The obtained results in the case study are validated against the obtained response with Matlab/Simulink®.

A combined control strategy of the three-phase shunt active power filter that is connected to a non-linear load network is proposed. The filter consists of a voltage source inverter on fully controlled switches, capacitor storage, and a first-order three-phase RL filter. The decomposition of the object of study according to the rates of motion of the dynamic system was performed. The fast subsystem is a circuit of compensation current control, the slow subsystem performs stabilization of the capacitor voltage. A double twisting algorithm to control the DC voltage is used. In it, to calculate the “operator variable”, in addition to the error of the capacitor storage voltage to increase the speed is also used its derivative. A two-dimensional sliding manifold to generate the compensating current is used. Each component of this surface is a linear combination of components of two-dimensional vectors. The first vector is the current error of the RL filter, the coordinates of the second are locally equivalent to the derivative of this error. The calculation of the instantaneous value of both components of the second vector by entering the second order sliding mode was forced. A simulation model is developed and the results of simulation are analyzed. A comparison of the proposed strategy with the traditional PI-regulation by the criteria of the duration of the transition process and the coefficient of harmonic distortions in the current consumed from the network is made.

This article provides two new features that in combinations facilitate the construction of a transfer function in RC and RL circuits, and in s-expanded polynomials. First is the introduction of tuple-based array manipulations, where multiplications and divisions are replaced with convolutions and deconvolutions, respectively. Second, it introduces a new UaL decomposition for tuple-based matrices. The UaL decomposition is proven to be computationally more efficient compared to the traditional LU factorization. It is shown that the growth of the entries in both U and L matrices are gradual and follow a geometrical pattern, as the decomposition progresses. Another important feature of the UaL decomposition is that it does not generate nonzero remainders, or simply, it is “cancellation free”. The method is applied to the MNA representation of an RC (or RL) circuit. Finally, it is shown that working in the tuple-based format puts the U and L matrix entries into s-expanded form, such as P(s) = a n sn + a n-1 sn-1 +…+ a 0 , which in turn produces s-expanded transfer functions.