IET Power Electronics
Volume 13, Issue 11, 19 August 2020
Volumes & issues:
Volume 13, Issue 11
19 August 2020
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- Author(s): Qianjin Zhang ; Mingxuan Mao ; Guo Ke ; Lin Zhou ; Bao Xie
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2165 –2174
- DOI: 10.1049/iet-pel.2019.1049
- Type: Article
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Photovoltaic (PV) power generation, as one important part of renewable energy, has been greatly developed in recent years. The stability of PV inverters is very important for the normal operation of PV systems. However, most PV systems, especially the large PV plants, locate in rural areas. The corresponding equivalent grid impedance is rather large and easy to lead to stability problems of grid-connected inverters and many researches have been done focusing on the stability problems. In this study, a survey of stability problems of PV inverters on weak grid condition is given. The stability problems are mainly divided into two parts, i.e. the control loops instability and inverter output voltage instability. The control loops cover the current loop and dc voltage loop. The output voltage instability refers to the voltage phasors relationship and the application of reactive power compensation. The non-linear parts of inverter dead-time, digital control delay, and phase-locked loop are explored. Future trends and challenges are given.
Stability problems of PV inverter in weak grid: a review
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- Author(s): Pezhman Bayat and Alfred Baghramian
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2175 –2193
- DOI: 10.1049/iet-pel.2019.1348
- Type: Article
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This study proposed a novel partly isolated three port converter (PITPC) based on a quasi-Z source converter for photovoltaic applications. Compared with the conventional quasi-Z source converter, the proposed DC–DC converter has dual input sources and uses the switched capacitors and coupled inductor techniques, helping the converter to gain a high voltage. To achieve the power flow control, the proposed converter uses only three power switches with low voltage stress and it is developed for hybridising photovoltaic panels, rechargeable batteries and isolated loads. For this purpose, the proposed PITPC can be easily reconfigured into dual-input single-output, single-input dual-output and single-input single-output modes; so it can even operate when the photovoltaic panel fails to provide energy to the load. Moreover, the study thoroughly discusses various converter operating modes and provides explanations and necessary relationships for circuit operations. The study also explains the control strategy as well as the pulse width modulation waveforms for the proposed converter. Simulation results from MATLAB/Simulink examine the proposed topology performance. The experimental results confirm the advantages claimed for the proposed converter; the results also show a well-distributed efficiency curve and a peak of 96.3%.
- Author(s): Hui Xiong ; Dawei Song ; Fengdong Shi ; Yiying Wei ; Liu Jinzhen
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2194 –2200
- DOI: 10.1049/iet-pel.2019.1620
- Type: Article
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Lithium batteries have become the main power source for new energy vehicles due to their high energy density and low self-discharge rate. In actual use of series battery packs, due to battery internal resistance, self-discharge rate and other factors, inconsistencies between the individual cells inevitably exist. Such inconsistencies will reduce the energy utilisation rate and service life of the battery pack, and even endanger its battery system safety. To improve the inconsistency of series battery packs, this study innovatively proposes an equalisation method based on a flyback converter. The residual power of a single cell is used as an index of inconsistency. A simple and reliable flyback converter is used to achieve balanced energy in the entire group, which make the energy is transferred between any batteries. Compared with the traditional equalisation topology, the equalisation topology proposed in this study reduces the number of components and reduces the volume of the equalisation system. Moreover, the primary side of the energy transfer only needs a set of control signals, which reduces the control difficulty. A series of equalisation experiments were performed using 12 series of battery cells. The results show the effectiveness of the proposed new equalisation method.
- Author(s): Changqing Yin ; Zhen Xin ; Wenlong Ding ; Poh Chiang Loh
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2201 –2211
- DOI: 10.1049/iet-pel.2020.0013
- Type: Article
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Split-source inverter (SSI) is a topology developed for flexibly stepping up and down its ac output voltage using only a standard inverter bridge. However, when configured as a single-phase inverter, it is still burdened by common second-order ripples. This study, therefore, proposes a modified SSI (MSSI) that can perform dual power decoupling. Unlike existing schemes, dual power decoupling makes use of both dc- and ac-side capacitors for diverting second-order ripples away from the dc source, which may be solar or other types of sources that do not work well with sizable ripples. Dual power decoupling, however, requires careful topological changes, before its effective realisation can be achieved with only a standard inverter bridge and a very small overall capacitance. Design of this capacitance and its comparison with passive decoupling have then been analysed, before testing the MSSI in experiments. Results obtained have verified the MSSI as an enhanced single-phase inverter with both buck and boost abilities while using no extra switches.
- Author(s): Lei Zhang ; Jiangchao Qin ; Di Shi ; Zhiwei Wang
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2212 –2221
- DOI: 10.1049/iet-pel.2019.1043
- Type: Article
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Modelling and simulation of a high voltage-level modular multilevel converter (MMC) is challenging due to large amount of semiconductor switches, various submodule (SM) circuits, and different operating conditions. Several equivalent models have been proposed for modelling and simulation in system level, which did not consider an industrial or digital controller. To accelerate MMC station design, a highly efficient model is needed with considering control parameters/strategies and accurate dynamics of voltage/current. In this study, an improved equivalent circuit model (ECM) is developed for large-scale system simulation and MMC station design. The proposed ECM considered the MMCs based on various SM circuits under different operating conditions. It can generate bipolar arm voltage and simulate static compensator under dc fault condition. Based on the proposed ECM, the influences of simulation time step on accuracy/efficiency are investigated by considering the sample period and voltage balancing strategies. This research is conducted based on an MMC-HVDC system in the PSCAD/EMTDC software. The study results demonstrate the effectiveness of the proposed ECM and show the relationship between simulation accuracy/efficiency and control/simulation parameters for determining simulation time step. Based on study results, the computational efficiency of proposed model is not significantly affected by the complexity of SM circuit.
- Author(s): Shri Prakash Sonkar ; Vivek Nandan Lal ; Rajeev Kumar Singh
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2222 –2235
- DOI: 10.1049/iet-pel.2019.1342
- Type: Article
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In this study, two 3-φ quasi-Z source inverters (qZSIs) with multiple ac outputs are proposed. The proposed topologies are developed from qZSI to obtain parallel mode and series mode 3-φ multi-output inverters. In parallel mode, the topology yields n-number of parallel ac outputs with different voltages and currents for different load conditions. For series mode, topology yields n-number of series ac outputs with same voltages and same load currents. Unlike voltage source derived multi-output inverters, the proposed inverters have all inherent properties of qZSI, like shoot-through protection and both buck–boost operations. For generating switching signals in these inverters, sinusoidal pulse width modulation with constant frequency shoot-through scheme is used. The proposed topologies fulfil more than one load demand at a time without any extra adaptor or regulator. The proposed inverters can be used for simultaneous multiple dc/ac power conversion for three-phase microgrid applications and three-phase residential loads. In this work, the proposed topologies with closed-loop control have been implemented for two inverter units, which is capable of supplying two ac outputs simultaneously. The mathematical modelling of the proposed topologies is carried out for performance analysis. The experimental results of 240 W lab prototypes have been presented to validate the proposed three-phase multi-output qZSIs.
- Author(s): Hoang Tran Ngoc ; Ty Trung Nguyen ; Hung Quang Cao ; Kien Minh Le ; Jae Wook Jeon
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2236 –2244
- DOI: 10.1049/iet-pel.2019.1128
- Type: Article
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To improve the accuracy of permanent magnet (PM) rotor position estimation for a hybrid stepper motor (HSM), the authors propose a sensorless control design based on the back electromagnetic force (back-EMF) caused by magnetic induction and harmonic rejection via an orthogonal third-order phase-locked loop (PLL3rd) and an integral harmonic filter (IHF). The accuracy of estimation is analysed considering PM rotor position estimation errors. The harmonics of the back-EMF signal are eliminated by the IHF before entering the PLL3rd, which synchronises and decreases position estimation error. This technique is a simple, reliable, and effective method for implementing sensorless control of an HSM. An industrial test-bench was used to implement the proposed scheme. The experimental results are presented to validate the effectiveness of the proposed estimation method.
- Author(s): Omar Abdel-Rahim and Haoyu Wang
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2245 –2251
- DOI: 10.1049/iet-pel.2020.0033
- Type: Article
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Multilevel inverter configurations are a suitable candidate for medium and high power applications. This study presents a new one-capacitor-based five-level (2V dc, V dc, 0, −V dc, − 2V dc) boost multilevel inverter. The single-phase version of the proposed formation has one dc-source, eight switches and one capacitor. To provide boosting ability, the inverter is operating based on charge-pump theory, where the capacitor is charging in parallel and discharging in series connections to provide a higher output voltage. The proposed configuration requires simple control tasks, and for this purpose, level-shift pulse width modulation strategy, where the reference signal is compared with four carriers, is implemented to drive the switches and generates the required pulses pattern. The developed inverter has some distinct features like the usage of only one dc-source and one-capacitor, compact size, simple control requirements and boosting ability. The system is simulated with MATLAB/Simulink and a hardware prototype is developed to verify the performance of the developed five-level configuration. The results show that the developed five-level multilevel inverter reaches the expected performance
- Author(s): Wei Liu ; Qinglin Zhao ; Deyu Wang ; Kunlun Li ; Yujie Wang
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2252 –2259
- DOI: 10.1049/iet-pel.2019.1470
- Type: Article
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A resonant inductor and two clamping diodes are introduced into the secondary phase shift full-bridge converter (SPS-FBC), which can well suppress voltage spike across the rectifiers. However, the resonant inductor and two clamping diodes will bring some other problems. In this study, an auxiliary winding in series with the resonant inductor is added to the SPS-FBC to reset the clamp diode current rapidly. The auxiliary winding not only reduces the circulation losses of the switches and the clamping diodes, but also makes the clamping diodes naturally turn-off and avoids the reverse recovery even when the output filter inductance and magnetising inductance are relatively large. The principle of operation and performance are illustrated and verified on a 1.5 kW experimental circuit. In addition, the efficiency and losses of the converters with/without reset winding are compared and analysed. The efficiency of the converter with reset winding is significantly improved over the entire operating range and the peak efficiency is 96.60% at full load.
- Author(s): Yi Han ; Ziling Nie ; Jin Xu ; Junjie Zhu ; Jun Sun
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2260 –2268
- DOI: 10.1049/iet-pel.2019.1334
- Type: Article
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In this study, a short primary six-phase linear induction motor (LIM) operating in high-speed non-periodic transient conditions is used as an object of study. In consideration of the coupling terms related to the dynamic end effect, the motor model is simplified and the vector control equation is deduced. A vector control strategy for the real-time modification of slip-frequency and torque current is proposed for dynamic thrust compensation. On this basis, considering the problems of thrust decay caused by dynamic end effect and dc-link voltage drop, this study puts forward a field-weakening control method to keep thrust constant before its decrease in the field-weakening region. The method makes it possible for the LIM to overcome the thrust decay and the narrowing of voltage limits under the high-speed operating conditions. The simulation and experimental results show that the proposed control strategies are useful for optimising the thrust in the transient process thus to realise the high-speed operation of the motor.
- Author(s): Vratislav Michal ; Zilio Nicolò ; Agostinelli Matteo
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2269 –2273
- DOI: 10.1049/iet-pel.2019.1234
- Type: Article
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This study describes a technique for automated and accurate inductance estimation in synchronous DC–DC buck and boost converters. The method of inductor value estimation is based on the dependence of the steady-state output voltage on the inductance value, in the case of a fixed inductor peak current. The measurement algorithm yields effective inductance value, and is aimed to be executed once during the start-up procedure under light load current condition. As the measurement is performed during the start-up sequence with low-load current, a dedicated current sensor with high accuracy can be employed, allowing to target high measurement accuracy in the range of ±5%. The presented technique is developed to enable the automated design of a digital controller for general purpose DC–DC converter but can be used in different applications such as analogue feedback-loop adjustment or improving the digital current estimator accuracy.
- Author(s): Yichao Wang ; Xiangqi Li ; Yan Li
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2274 –2280
- DOI: 10.1049/iet-pel.2019.1141
- Type: Article
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The increasing penetration of renewable power sources into power system is calling for an evolution of grid interconnection control strategy. In particular, during asymmetrical grid faults, power turbulence and current distortion of three-phase inverter cannot be balanced unless coordinated control is adopted. Several coordinated control strategies are usable for operating under unbalanced grid voltage nowadays. These control strategies usually require a real-time sequence detection block for reference generation. This study explores a coordinated control strategy without real-time sequence detection. It has three theoretical innovations: (i) the internal mathematical connection between power fluctuation and current quality is derived; (ii) a control strategy with a continuous adjustable factor is proposed. The power oscillations and the current quality can be controlled flexibly by adjustment factor without using the filter and sequence extraction calculation; (iii) the method for selecting the continuous adjustable factor is also presented. The experiment and simulation results prove that these innovations facilitate power-current coordinated control with simple reference selection criteria and excellent performance.
- Author(s): Trung Tran ; David Raisz ; Antonello Monti
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2281 –2292
- DOI: 10.1049/iet-pel.2020.0174
- Type: Article
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This study proposes a novel method that combines sliding mode control (SMC) and virtual oscillator control (VOC) to eliminate voltage harmonics and unbalance caused by non-linear and unbalanced loads in a three-phase low-voltage microgrid. The conventional VOC is modified to fit the three-phase four-leg inverter systems and a novel SMC control is designed using the high-pass filter technique and linearised super twist algorithm. The proposed control method can keep the voltage harmonics and unbalance at the point of common coupling within the IEEE standard limits, under heavily non-linear and unbalanced load conditions. The validity of the proposed method is verified by both offline simulations in Matlab/Simulink and Control Hardware-in-the Loop simulations using an OPAL-RT platform.
- Author(s): Jiarong Wu and Yimin Lu
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2293 –2301
- DOI: 10.1049/iet-pel.2019.1160
- Type: Article
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To minimise the cross-regulation of single-inductor multiple-output switching converters, an exact feedback linearisation (EFL) optimal control strategy is proposed in this study. Using the single-inductor dual-output (SIDO) boost converter as an example, an affine non-linear system based on the non-linearity of the system is established, the mechanism of the low-voltage output of the SIDO boost converter is analysed in detail. Then the qualification of the established model for EFL is theoretically confirmed. Meanwhile, the corresponding output functions for the linearisation of the non-linear system in Brunovsky normal form are constructed, and the theoretical grounds supporting the ability of the output functions to track the reference outputs are further investigated. In addition, the optimal control technology is applied to EFL control to obtain the non-linear control law of the system. Furthermore, the design method of optimal feedback coefficients is given, and a SIDO boost converter system with low-voltage output is designed and realised. The simulation results show that this control strategy provides a better regulation performance than common-mode and differential-mode voltage control strategies and that it can effectively minimise the cross-regulation of the system. Finally, the experimental results further verify the correctness and effectiveness of the proposed control strategy.
- Author(s): Ningrui Yang ; Jun Zeng ; Renjun Hu ; Junfeng Liu
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2302 –2311
- DOI: 10.1049/iet-pel.2019.1199
- Type: Article
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High step-up, high-efficiency and cost-effective dc–dc converters with high power density, as an interface to boost the low voltage of alternative sources to the utility voltage level, are an important part of renewable energy systems. In this study, a novel high step-up converter is proposed with a switched-capacitor. By introducing the switched-capacitor unit in the converter, the voltage of the switched-capacitor is coupled into the charging circuit of the input filter-inductor. Thus, the boost factor can be enlarged up to (1 − 2D) and the problem of the inrush current can be avoided due to the filter inductor. By replacing the filter inductor with the voltage multiplier unit, the boost coefficient of one coupled inductor voltage multiplier is increased to 2n and the voltage stress of the power switch is significantly reduced. Moreover, the energy of the leakage inductor is recycled by the switched-capacitor with the reduction of the voltage spike and the switches’ stress. The working principle and the steady-state characteristics are analysed in detail in this study, and a comparison is made between the proposed converter and other high step-up converters. The experimental results based on a 200 W 20 to 200 V prototype verify the correctness and the feasibility.
- Author(s): Abdulhakeem Mohammed Dobi ; Mohd Rodhi Bin Sahid ; Usman Ullah Sheikh
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2312 –2321
- DOI: 10.1049/iet-pel.2020.0085
- Type: Article
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This study proposed a novel non-isolated half-bridge Inductor-Inductor-Capacitor (HB LLC) resonant converter with automatic resonant frequency adjustment ability and a circulating current suppression auxiliary circuit. The proposed converter employs a hybrid modulation technique based on frequency modulation (FM) and pulse width modulation (PWM) to regulate the output voltage. At the nominal operating point, all the excellent attributes of a conventional LLC converter over the entire load range are maintained and output voltage control is achieved with FM. However, when the input voltage decreased to a level that LLC output voltage cannot be maintained with FM, the primary switches will operate at the minimum switching frequency and the auxiliary switch will be turned ON with PWM. The auxiliary switch is turned ON with zero-voltage switching and automatically matching the circuit resonant frequency with the switching frequency for optimal operation. The effective resonant inductor is energised directly from the dc bus storing more energy which is later released to the load to achieving high gain while maintaining the desired output voltage with a narrow frequency span. In addition, the converter exhibits low circulating current under an enhanced gain condition. Experimental results are presented on a 60 W prototype to validate the theoretical prediction. The proposed converter has a peak efficiency of 97%.
- Author(s): Milad Rezaie and Vahid Abbasi
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2322 –2333
- DOI: 10.1049/iet-pel.2019.1070
- Type: Article
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This study proposes a high step-up DC–DC converter based on quadratic boost converter. The proposed converter is composed of a quadratic boost converter and a multiplier cell. The converter can be used in low power applications which need to increase output voltage with high gain. In order to reduce number of the components, the multiplier cell is composed with the quadratic boost converter in a way to share one of their inductors. The found location of the multiplier adds some advantages to the proposed converter in comparison to the similar converters. The converter advantages include higher voltage gain, lower voltage stress on diodes and capacitors and requiring smaller inductors. To verify the points, principle operation of the converter is analysed and it has been compared with other converters. The proposed converter is designed and implemented using its main equations. Experiments are done along the lines of the analysis to prove that they have good accordance with each other. Operation quality factors such as voltage stress, voltage gain, efficiency, dynamic of the converter and operation in transient conditions are investigated using the experiments.
- Author(s): Minghui Wang ; Yongxiang Xu ; Jibin Zou
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2334 –2341
- DOI: 10.1049/iet-pel.2019.1233
- Type: Article
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In some cases, LC filters are installed between the inverters and motors to suppress the adverse effects of pulse width modulation. However, some techniques should be modified, because the mathematical model of the drive system is changed by the LC filter and the sensors on the inverter output cannot measure some necessary variables. In this study, a multi-purpose proportional-integral (PI) observer is proposed at first. The type of observer depends on whether the position sensor is equipped. A sliding mode controller for the LC filter based on the observer is presented, therefore improving the dynamic performance. Furthermore, if the position sensor of the rotor is equipped, an open-switch fault diagnostic method is realised by means of the PI observer; if the position sensor is not equipped, the sensorless estimation is realized. The proposed strategies were realised without any additional current/voltage sensors. Experimental results verified the effectiveness of the proposed strategies.
- Author(s): Shoulong Dong ; Yilin Wang ; Jianhao Ma ; Weirong Zeng ; Yingjiang He ; Liang Yu ; Yuye Hu ; Shuo Zhang ; Chenguo Yao
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2342 –2349
- DOI: 10.1049/iet-pel.2019.1184
- Type: Article
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A modular solid-state pulse generator based on a multi-turn linear transformer driver (LTD) is designed for the application of pulse power techniques with a high voltage, large current and wide pulse width. The LTD adopts the method of multi-turn winding on the magnetic core, which can help to output pulses of wide width. The isolation of the power supply with windings in the same direction of the LTD modules is designed, and the isolation voltage of the magnetic cores is the working voltage of the LTD modules. A modular solid-state pulse generator based on the multi-turn LTD is developed, which is composed of 10 LTD modules. Each module consists of 18 energy storage capacitors, metal-oxide-semiconductor field-effect transistors and their driving circuits connected in parallel. The pulse generator can output pulses with parameters including a voltage ranging from 0 to 5000 V, a pulse current up to −500 A, and a pulse width ranging from 200 ns to 5 μs. When all modules work in synchronisation, rectangular pulses can be produced with a rise time of 30 ns and a fall time of 16 ns. If all modules are asynchronised, trapezoidal pulses are produced with adjustable step-like rising and falling edges. Moreover, a higher-voltage pulse can be achieved by increasing the number of LTD modules.
- Author(s): Sourabh Kundu ; Subrata Banerjee ; Supratik Bhowmick
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2350 –2360
- DOI: 10.1049/iet-pel.2019.1295
- Type: Article
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This study proposes a selective harmonic minimisation-pulse amplitude modulation (SHM-PAM) technique utilising least number of switching based on optimised waveform pattern for five-level cascaded H-bridge (CHB) inverter to satisfy the NRS 048-2:2003 grid code standard. Here, particle swarm optimisation method is used to evaluate the solution of the optimised switching angles and variable DC-link voltages. A comparison between the proposed SHM-PAM and conventional selective harmonic elimination-pulse width modulation (SHE-PWM) techniques has been carried out by harmonic performance analysis (total harmonic distortion (THD), weighted current THD and harmonic loss factor) and loss analysis (conduction, switching and their cumulative losses) of the switches of five-level CHB inverter under different load power factor angles for medium-voltage application. The performances of the conventional SHE-PWM and proposed SHM-PAM techniques are examined through experimentation using a three-phase five-level CHB inverter. Finally, the proposed technique based 5-level CHB inverter is applied to shunt active power filter using tuned proportional plus parallel resonant current controller for improvement in power quality under non-ideal grid conditions.
- Author(s): Pedro José Faure Gonçalves and Eloi Agostini Jr
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2361 –2371
- DOI: 10.1049/iet-pel.2019.1373
- Type: Article
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This study proposes the generalised analysis of the interleaved zero-voltage-switching (ZVS) boost-flyback converter containing a number k of interleaving cells. The analysis provides a general description of the energy transfer process of the circuit and yields a systematic approach for the adequate converter design. The effect of the leakage inductance on the voltage gain is verified in detail, enabling the designer to deal with the trade-off between high step-up operation and soft-switching occurrence. In addition, the conditions to guarantee ZVS for all switches are investigated, providing the basis for the adequate choice of the auxiliary switching capacitance and dead time. Experimental results obtained from the testing of a 500 W, 100 kHz, 96.9% peak efficiency prototype validate the analysis carried out and the proposed design procedure for the converter.
- Author(s): Elias D. Tsirbas ; Frangiskos V. Topalis ; Evangelos N. Skoubris
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2372 –2379
- DOI: 10.1049/iet-pel.2020.0127
- Type: Article
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Prior to the design of the feedback system for a boost converter, a suitable switching frequency for the transistor has to be determined. A non-linear method for determining this frequency via an experimental open-loop converter model is studied. Utilising the open-loop model as an investigative tool, two non-linear distinct resonant frequencies have been found to be a source of chaos. This condition for chaos holds when the boost diode's reverse-recovery time, its non-linear capacitance, as well as the inductance are the combined parameters within these frequencies. When the switching frequency is synchronised with these frequencies, ultra-harmonics, period-doublings and sudden transitions to chaos occur for various switching frequency ranges. The dependence equations of our theoretical model that incorporate these resonant frequencies predict the unstable frequency regions. The authors’ numerical method utilises a bifurcation peak-to-peak analysis that detects the waveform periodicity of certain voltage variables. Highly unstable behaviour of the converter is reported both in simulation and in the laboratory. The periodic and non-periodic regions are confirmed by the corresponding computations of the Lyapunov exponent, Poincaré sections, frequency spectra and bifurcation diagrams.
- Author(s): Mana Hoseinzadeh Lish ; Reza Ebrahimi ; Hossein Madadi Kojabadi ; Josep M. Guerrero ; Naser Nourani Esfetanaj ; Liuchen Chang
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2380 –2389
- DOI: 10.1049/iet-pel.2020.0117
- Type: Article
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In this study, due to the low output voltage that often is presented by renewable energy sources like photovoltaic panels, a single switch high step-up dc–dc converter with high efficiency is proposed. The presented step-up dc–dc converter uses a coupled inductor and diode-capacitor technique to achieve high voltage gain. By changing the turns ratio of the coupled inductor, this novel topology does not need to operate at a high duty cycle conditions to obtain the high voltage gain. Moreover, the leakage inductance energy of the coupled inductor is recovered by using two passive clamp circuits to reduce the stress across the semiconductor devices, which improve efficiency. The operating modes of the proposed converter and the theoretical analysis are considered and finally, a prototype setup has been implemented to accredit the accuracy of the theoretical and simulation analysis.
- Author(s): Alessandro Barbato ; Marco Barbato ; Matteo Meneghini ; Marco Silvestri ; Thomas Detzel ; Oliver Haeberlen ; Giorgio Spiazzi ; Gaudenzio Meneghesso ; Enrico Zanoni
- Source: IET Power Electronics, Volume 13, Issue 11, p. 2390 –2397
- DOI: 10.1049/iet-pel.2019.1455
- Type: Article
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This study presents a novel system to investigate the on-wafer level dynamic properties of GaN-based power transistors in hard-switching application conditions. The system is able to analyse devices with an on-resistance (R DSON) in the range from few ohms to hundreds of ohms, and can be effectively used to improve the development process of GaN high electron mobility transistors (HEMTs) power devices at the wafer level. Contrary to the conventional double-pulse setup, where a resistive load is usually used in combination with a very low duty cycle, the dynamic R DSON is acquired during realistic operating conditions, in a boost converter circuit. Consequently, the authors’ system is able to study not only the field-activated trapping processes, but also those induced by hard-switching conditions, i.e. promoted by hot electrons and self-heating. The maximum working voltage (600 V) and the minimum R DSON measurement time after turn-on (2 µs) allow evaluating the operation limit of the devices in a voltage/frequency range close to real switching conditions. Working on the wafer level allows a more realistic assessment of the dynamic R DSON behaviour before the packaging phase, which is very important to improve the production and development process of GaN-HEMT devices.
Partly isolated three-port DC–DC converter based on impedance network
Novel voltage equalisation circuit of the lithium battery pack based on bidirectional flyback converter
Modified split-source inverter with single-phase dual power decoupling
Improved equivalent circuit model of MMC and influence analysis of simulation time step
Three-phase quasi-Z source inverters with regulated multiple AC outputs for microgrid applications and three-phase residential load
Improving the accuracy of permanent magnet rotor position estimation for stepper motors using magnetic induction and harmonic rejection
Five-level one-capacitor boost multilevel inverter
Secondary-side phase-shifted full-bridge converter with reset winding
Control strategy for optimising the thrust of a high-speed six-phase linear induction motor
Low-complexity inductance estimation for switched-mode power converters using peak-current mode control
Power-current coordinated control without sequence extraction under unbalanced voltage conditions
Harmonic and unbalanced voltage compensation with VOC-based three-phase four-leg inverters in islanded microgrids
Exact feedback linearisation optimal control for single-inductor dual-output boost converter
Novel non-isolated high step-up converter with fewer passive devices and low voltage stress of power switches
Non-isolated LLC resonant converter with suppressed circulating current and automatic resonant frequency matching capability
Effective combination of quadratic boost converter with voltage multiplier cell to increase voltage gain
Sliding mode control with open-switch fault diagnosis and sensorless estimation based on PI observer for PMSM drive connected with an LC filter
Modular solid-state pulse generator based on multi-turn LTD
Improved SHM-PAM-based five-level CHB inverter to fulfil NRS 048-2:2003 grid code and to apply as shunt active power filter with tuned proportional-resonant controller for improving power quality
Generalised analysis of the high-voltage-gain interleaved ZVS boost-flyback converter
Non-linear bifurcation method to determine the boost converter switching frequency
Novel high gain DC–DC converter based on coupled inductor and diode capacitor techniques with leakage inductance effects
Fast System to measure the dynamic on-resistance of on-wafer 600 V normally off GaN HEMTs in hard-switching application conditions
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