Search

A high-efficiency diode-clamped linear amplifier (DCLA) has been proposed to realize low electromagnetic interference caused by switching operations. In this article, a new concept of the DCLA, namely the higher efficiency unequally divided voltage power supply DCLA (DCLA-UeDV), is proposed—it uses the same circuit topology but changes the supply voltage ratio of the series-connected supply. It is well-known that the main loss component of a DCLA is caused by the semiconductor device under linear operation depending on the supply voltage and current flowing. In a conventional DCLA, an equally divided voltage is used to supply power. In this study, a lower supply voltage is applied for a higher current device, and a higher supply voltage is applied to the lower current device in the proposed DCLA-UeDV—the optimized voltage ratio being theoretically derived. Applying the optimized voltage ratio to a four-stage DCLA-UeDV, the power loss theoretically decreased by 10.7%, resulting in an efficiency improvement of 1.7 percentage points. The validity of the proposed method was verified by simulations of a four-stage and an eight-stage DCLA-UeDV and experiments based on the four-stage device. [ABSTRACT FROM AUTHOR]

The moving-coil type voice coil motor (VCM) has very light moving mass, which can achieve higher reciprocating frequency and work efficiency. However, the power supply lead connected to the moving coil can be easily broken under long-term reciprocating motion, so it is rarely used in compressor drive systems. The core technology of the compressor development trend is a driving motor with high-efficiency, high reciprocating frequency, certain piston stroke, and light moving mass. Due to its structural characteristics, the moving-coil type VCM has broad application prospects. This article proposes a new structure for power supply of a moving coil VCM based on the principle of electromagnetic induction. The proposed VCM can overcome the problems of aging and disconnection of power supply lines caused by reciprocating motion, and meet the requirements of high-frequency and long-term repetitive action of the moving coil. The content of this article is as follows. First, the construction of the proposed VCM is introduced. Second, the power-driven circuit based on interleaving double switch forward converter is provided. Finally, two working modes of drive circuit for reciprocating motion are proposed. Simulation and experimental results verify the effectiveness of the method. [ABSTRACT FROM AUTHOR]

Plasma application systems can be classified as an inductive-coupled plasma (ICP) system and a capacitive coupled plasma (CCP) system. Generally, a voltage-source-type pulse generator (VST-PG) is utilized in ICP systems. The VST-PG has the intrinsic problem of spike currents and voltage ringing in CCP systems. A filter inductor and damping circuit have been employed to mitigate this problem. However, this solution degrades the dynamic performance and increases the system cost, particularly for a CCP system with a large power rating. This article proposes a current-source-type pulse generator (CST-PG) to solve the problem of current spike and voltage ringing in a CCP system. The proposed circuit structure provides the output voltage and current waveform of the enhanced waveform fidelity. In the proposed system, two current sources of different scales are connected in parallel to generate the output current with high precision. The entire system consists of four major functional blocks: a bias current generator, a bias current modulator, a slope current generator, and a slope current modulator. The proposed solution also employs a SiC mosfet-type power semiconductor switch of 1200 V/90 A to meet the fast transient requirement. The proposed converter system successfully satisfies the specification of an output voltage of 1.6 kV and an output current of 35 A with a fundamental frequency of 100 kHz. The experimental validation result confirms the superior performance of CST-PG with a reduced crest factor of 1.12 for a laboratory prototype. [ABSTRACT FROM AUTHOR]

The envelope tracking (ET) power supply can output a variable voltage which tracks the envelope of the radio frequency input signal to the power amplifier (PA), and the system efficiency can be significantly improved. To achieve a high tracking bandwidth, the switching frequency of the ET power supply is usually too high. The pulse edge independent distribution (PEID) method has been proposed to reduce the switching frequency to 1/n (n ∊ N) of the tracking bandwidth, but a large number of isolated voltage sources are needed, leading to increased power stage and system complexity. In this letter, a switched capacitor based high bandwidth ET power supply is proposed, which employs optimized charging topologies and mechanisms to stabilize the voltages across the switched capacitors, and thus they can fully replace the isolated voltage sources. Since the proposed configuration is derived from the PEID method, all the features of PEID method are retained. A prototype with 6−26-V output voltage and 20-W peak output power is fabricated and tested with a 1-MHz sine wave and a 5-MHz bandwidth communication envelope. The experimental results validate the proposed configuration. [ABSTRACT FROM AUTHOR]

Track wireless power transfer (WPT) systems are increasingly used for monorail robots, industrial transportation, etc. Conventionally, the track WPT system's primary power supply is designed to be equal or higher than the total running pickups’ rated power. However, in practice, some of the pickups may transiently require more power than their normal operating state. It is not cost effective to increase the power rating of the primary source for the transient case. Hence, this article proposes a method to strengthen the track's power transfer capability by reversely injecting energy from available online pickups to the transiently over-rated one. A bioperation mode is proposed, which includes both the normal operation and the strengthening operation. A bidirectional pickup topology is used, and the equivalent circuit is analyzed accounting the bioperation mode. In addition, a synchronization method of the primary and reverse injection pickups is proposed. A criterion to determine the boundary of the reverse energy injection is also presented. By detecting the peak current, this energy injection method can be practically implemented and the proposed method is verified through the experimental results. [ABSTRACT FROM AUTHOR]

This article presents the design of a new closed loop technique that reduces the common mode conducted emission. It can be applied to any kind of switching circuit in which couples of outputs are modulated by a bipolar PWM signal. It is based on the compensation of the delay between complementary output switching edges, using a simple sensing circuit and a low computational effort software algorithm, which is implemented in a microcontroller driving the switching circuit. One of the main advantages of the proposed solution is the reduction of the disturbance energy, without affecting the system efficiency. The technique is practical to implement, and the measurements performed on a power inverter prototype confirm the theoretical analysis outcomes about the reduction of the conducted emission in the lower-to-medium frequency range. [ABSTRACT FROM AUTHOR]

This article proposes a hybrid model predictive control (HMPC) for a modified modular multilevel switch-mode power amplifier (M3-SMPA). The M3-SMPA consists of two parts connected in series including modular multilevel converter (MMC) and full-bridge converter (FBC). Different from available MPC methods that only apply either finite control set MPC (FMPC) or modulated MPC (MMPC), the proposed HMPC method synthesizes the merits of both FMPC and MMPC on different timescales. First, the optimal control option (CO) for MMC is calculated by FMPC with the multiple control objectives, including output voltage control, circulating current control, and submodules (SMs) capacitor voltages balance control. Then, based on the above-mentioned optimal CO, the optimal duty cycle for FBC is calculated by MMPC with a single objective of output voltage control. In this case, the FMPC achieves the multiobjective control of MMC while the MMPC eliminates the tracking error of output voltage using FBC with a fixed switching frequency. Furthermore, a circulating current injection method is presented to balance the SMs capacitor voltages and an improved adjacent search method is introduced to reduce the evaluated COs for MMC in each control period. The effect of dc-link voltage configuration for FBC on output steady-state performance is also analyzed. Finally, the effectiveness of the proposed HMPC method is verified by experimental results. [ABSTRACT FROM AUTHOR]

This article proposes a highly efficient mission profile emulator (MPE) for submodules (SM) in modular multilevel converter (MMC), with respect to its basic circuit topology, control method and design. By using a common three-phase dc–ac power converter, as well as some analytical equations of MMC, the proposed MPE is capable of emulating operating conditions of multiple SMs in the MMC system. Compared with existing single-phase testing methods, the proposed three-phase structure achieves better testing efficiency. In the proposed MPE, two testing units of SMs, including four different mission profiles of submodule, are tested simultaneously with low requirements on dc power supply voltage. The comparisons between the complete MMC system and the MPE in the simulation, as well as experimental measurements, are given to verify the validity and accuracy of the proposed testing approach. [ABSTRACT FROM AUTHOR]

Soft normally open points (SNOPs) connected to distribution networks are instrumental in maintaining uninterrupted power supply and improving power quality during the fault period. In order to achieve the optimal service restoration scheme, a novel bi-level service restoration model based on the robust optimization method is proposed in this paper. The upper level of the proposed model aims at minimizing the risk of load loss. The switch statuses and range of power transmitted by SNOP terminals can be obtained. In the lower level of the model, the interval robust optimization method is adopted to cope with the uncertainties of DGs and loads. If there are no optimal solutions, the upper level model needs to be solved once more to adjust the network topology. Finally, a test system is established to verify the effectiveness of the proposed model and solution method. The effects of forecasting errors, the DG penetration, and the ratio of single terminal capacity of SNOP to line capacity on the optimization results are analyzed. [ABSTRACT FROM AUTHOR]

Under extreme events, distribution systems may suffer blackouts and numerous restoration tasks will compete for limited crews and facilities. To enhance the resilience of distribution systems, multiple resources should be fully coordinated, coupling relationships between fault location, fault isolation, and service restoration should be considered, and flexible strategies should be formed for different situations faced by distribution systems. To this end, a comprehensive resilience-oriented fault location, fault isolation, and service restoration (RO-FLISR) method is proposed in this article, where, the fault location, fault isolation, and service restoration under extreme events are comprehensively considered at the same time for the first time, and multiple resources are coordinated. Three basic modules are formulated in the RO-FLISR method, i.e., the possible faulted zone determination (PFZD) module which could determine all the possible faulted zones when there are multiple faults and DGs, the line patrolling (LP) module which supports the optimal scheme for line paroling based on crews, and the fault isolation and service restoration (FISR) module in which the operation of MSs and RCSs are coordinated for comprehensive fault isolation and service restoration. The modules are formulated as MILP models. Effectiveness of the proposed method is verified with the IEEE 123-bus system. [ABSTRACT FROM AUTHOR]

This article presents a fully integrated flipped voltage follower (FVF) based low-dropout (LDO) regulator with enhanced full-spectrum power supply rejection (PSR) and unity-gain bandwidth over 400MHz for noise-sensitive circuits. Following the study of three types of FVF LDO's PSR performances, we propose a novel FVF LDO with a low-gain fast loop-1 and a high-gain slow loop-2. In prior FVF LDOs, their PSRs are either full-spectrum, or not, but with low PSR at low frequency. In this article, we fully utilize both dc gains of loop-1 and loop-2 for the low-frequency PSR, while the high-frequency PSR remains unchanged. In addition, we use dynamic compensation to push the loop-2's UGB to higher frequency for a better PSR bandwidth. This work, fabricated in 65 nm complementary metal oxide semiconductor (CMOS), with 1.2-V input and 1-V output, exhibits a measured quiescent current (IQ) varying from 27 to 82 μA for a load current ILOAD between 5 μA and 20 mA. The circuit achieves a low frequency PSR of –58 dB with the worst full-spectrum PSR of –9 dB in 20 mA ILOAD with a 300 pF on-chip output capacitor. Further, with an UGB over 400 MHz, the proposed FVF LDO reaches 0.9 ns response time when ILOAD changes between 100 μA and 20 mA with edge times less than 0.8 ns. [ABSTRACT FROM AUTHOR]

This article presents a cascaded gate drive power supply configuration to reduce the common mode (CM) current in phase-shifted full-bridge (PSFB) converters. In such converters, there are at least two $dV/dt$ sources generated at different floating points associated to the parasitic capacitances of the isolated barriers of the gate drivers (power supplies, and control signal isolation units), which can increase the conducted electromagnetic interference perturbations. This article is focused on the analysis of a new gate drive power supply configuration, which reduces the CM currents that circulate in the control part of the switching cells. This improvement is achieved by modifying the impedance network of CM current pathways. Experimental results are provided to prove the effectiveness of the new gate drive power supply configuration on a PSFB converter based on SiC-MOSFET devices. [ABSTRACT FROM AUTHOR]

This article presents a novel high step-up multilevel inverter (MLI) with a single dc source based on switched-capacitor modules in which it is suitable for the renewable energy applications with low-voltage dc source. The proposed topology has the ability of the voltage self-balancing for the capacitors without any external or closed-loop circuits. Another merit of the proposed structure is the production of bipolar staircase waveform without any end-side full-bridge in which it reduces the voltage stress on components remarkably. The circuit topology and its operation principle, capacitance calculations and comparison of the proposed circuit with other well-known single-source MLIs are discussed in detail. Finally, a 21-level prototype of the proposed inverter with 32 V input voltage and high gain 10 by using four modules was evaluated by both simulation and experimental tests. [ABSTRACT FROM AUTHOR]

An accuracy-improved and internal regulator-free temperature on-chip sensor is proposed. The proposed sensor outputs an accuracy-enhanced pulse width modulation (PWM) signal with a nonlinear current mode feedback pseudo-PLL (Phase-Locked Loop). The pseudo-PLL is able to greatly mitigate the nonlinearity caused by process parameters (eg. threshold voltage and mobility of MOS transistor) without careful compensation. Furthermore, to optimize the area and power supply rejection without an internal regulator, a current mode input and feedback approach in the pseudo-PLL is also presented. The proposed sensor is fabricated with 0.18 2μm standard CMOS process. The measurement results show that the power consumption of the sensor is only 2 μW under 1.2V supply voltage. With the supply voltage varying within 1~1.2V, the temperature detection error is maintained within +/−0.2°C in the range of −20°C to 100°C. And the corresponding power supply rejection (PSR) ratio and resolution achieve about 0.15°C/100mV and 0.12°C, respectively. [ABSTRACT FROM AUTHOR]

For the electric vehicle (EV) dynamic wireless charging system, mutual inductance is an important factor affecting the output power. In this article, a fast and general method to calculate mutual inductance is proposed. This method can calculate the mutual inductance of magnetic couplers with different receiver structures and receiver positons by only one simulation, and it can also provide a theoretical guidance for the receiver design. Calculation models for different receiver structures are established, and the mutual inductance calculation-coefficients are proposed to describe the functional relationships between mutual inductance and receiver's parameters. Based on the concept of mutual inductance calculation-coefficients, the surface-integral in the conventional analytical calculation method can be simplified to be the product of these coefficients and magnetic flux density's amplitude, and then the calculation difficulty of the mutual inductance can be reduced. Finally, a prototype was built for experimental verification. The experiment results show that the max error between the measured mutual inductance and the calculated result is only 1.56%, which verifies the feasibility and the accuracy of the proposed calculation method. [ABSTRACT FROM AUTHOR]

A tie-line security region provides all possible tie-line power injections with which constraints in a regional network will not be violated. With the high penetration of renewables, a sharp increase or decrease of renewable power requires a good depiction of the tie-line security region considering time coupling. However, the tie-line power security region with time coupling is a high-dimension polytope, which leads to a considerable computational burden. This paper presents a fast algorithm to approximate the original high-dimension tie-line security region considering time coupling. A few lower-dimension polytopes associated with combinations of different periods are calculated for the approximation. An evaluation method with clear physical explanations is established to measure the accuracy of the approximation. The method converts the evaluation to two linear programming problems based on the mathematical relationship between optimal points and polytope vertices. Under a Monte Carlo framework, the statistical analysis is employed to measure the accuracy using five presented indices. The performance of the proposed methods is verified by the case studies on the IEEE 118-bus test system and a 661-bus utility system. [ABSTRACT FROM AUTHOR]

A simultaneous bidirectional single-ended link is realized in TI’s 130-nm BiCMOS technology without any replica drivers. We measure a jitter tolerance of about 0.7 UIpp at 10 MHz for the 24-Gb/s forward channel with 18.3-dB loss at a bit error rate (BER) < 10−12, while consuming 141.25 mW in the bidirectional drivers and receiver front-ends. Furthermore, the architecture has been extended to support transfer of dc power over coax in addition to high-speed signaling. [ABSTRACT FROM AUTHOR]

Nuclear quadrupole resonance (NQR) technology is a promising approach to detect so-called “minimum metal” landmines, as it can look directly for their explosive content. Conventional commercially available NQR devices, however, are large and expensive, and they require a transmitter power amplifier with a power generator, which is not suitable for outdoor use and mass production. Here we present a small and inexpensive portable device developed for detecting landmines using NQR. The device uses a field-programmable gate array (FPGA) and low-impedance transmission and reception circuits that include a dual supply class-D power amplifier powered by conventional batteries to ensure sufficient magnetic field excitation for mine detection. The pulse width modulation signals that are fed into the power amplifier have been designed to protect the low impedance transmit-receive switch circuit from the high voltage. The system has been tested successfully in the laboratory with 100g of explosive RDX at a distance of 10cm from the antenna, corresponding to a plausible anti-personal (AP) mine scenario. Detection was achieved with a signal to noise ratio (SNR) ~2 in 2/3 of the time that a previous prototype required (120 sec). Moreover, the new device can detect RDX explosives with a measurement time and SNR comparable to mine detectors built with commercial-off-the-shelf (COTS) components, but at lower cost and smaller form factor. [ABSTRACT FROM AUTHOR]

This article proposes an optimal strategy by using line hardening and energy storage system (ESS) deployment to enhance the distribution system (DS) resilience in natural disasters. A multi-stage multi-zone DS line state set is established, based on the conceptual resilience quantification, to reflect spatial and temporal characteristics of the severe contingencies. To address random contingencies, the proposed problem is formulated as a defender-attacker-defender (DAD) model that minimizes the weighted load shedding in the worst-case scenario, and the column-and-constraint generation (C&CG) algorithm is used to solve the model efficiently. The effectiveness of the proposed strategy is verified on the modified IEEE 33-node DS and a modified power grid representing a province in China. [ABSTRACT FROM AUTHOR]

This work presents a novel gated- diode SCR-incorporated BJT (SIB) structure for ESD protection purpose. A gated diode built in the SIB structure modulates reverse-biased P+ / N-well diode for better junction breakdown control. This device could achieve high TLP second breakdown current /ESD threshold close to that of an SCR, very high holding voltage, and reduced trigger voltage, as well as excellent latchup immunity. [ABSTRACT FROM AUTHOR]