An interleaved boost dc/dc converter with zero-voltage-transition (ZVT) characteristics is presented in this study. The interleaved approach is used in this presented converter to not only decrease the current stress of the main circuit device but reduce the input ripple current and output capacitor size. Moreover, the presented converter only uses a common ZVT auxiliary circuit for achieving the soft-switching function. Thus, the presented converter can further reduce the size and cost. The ZVT characteristic for active power switches and zero-current transition characteristic for power diodes can be achieved to reduce the switching losses of active power switches and eliminate the reverse recovery losses of power diodes. The efficiency can be improved with a wide range of load. This topology can operate at two operational modes D > 50 and D < 50% to increase the application range. The operational principle and design consideration are discussed in detail. Finally, experimental results taken from a 1500 W prototype are presented to confirm the effectiveness of the presented converter.

This study introduces a new dual switches converter with a high voltage gain and reduced power device voltage stress. Using a three-winding coupled inductor and voltage multiplier, the proposed converter achieves a high step-up voltage gain without a large duty cycle. However, unlike other converters with coupled inductor, the power device voltage stress in the proposed converter is dramatically reduced. The two clamped diodes not only alleviate the voltage spike across the metal–oxide–semiconductor field-effect transistor (MOSFET), but also reduce the diode reverse recovery issue. The efficiency can be improved as circuit allows the use of low on-resistance MOSFETs and Schottoky diodes in applications where this might not have been possible with conventional topologies. The basic operational principle and relevant theoretical analysis are presented in this study. Finally, practical results from a laboratory prototype are presented to verify the performance of the proposed converter.

The pulse-width amplitude modulation (PWAM) method was proposed for the single-phase quasi-Z-source inverter (qZSI)-based photovoltaic (PV) power system to reduce quasi-Z-source (qZS) impedance values while improving efficiency. The method modified sinusoidal pulse-width modulation (SPWM) of the qZSI by combining pulse-amplitude modulation (PAM) and a varied dc-link voltage envelope was produced. The SPWM worked at low dc-link voltage, lowering voltage stress and avoiding shoot-through switching. The PAM worked at the varied dc-link voltage, reducing the number of switching events. As a result, the power dissipation decreased compared to working at the constant dc-link voltage. This study further investigates the PWAM-based single-phase qZS PV inverter system. An improved topology with control strategy is proposed for its grid-connected and standalone operation. Design method of impedance parameters is detailed. The performance in boost and buck operation is discussed when the single-phase qZSI using SPWM and PWAM. Simulation and experimental results verify outstanding features of the PWAM for single-phase qZSI, and the proposed approach for dual-mode operation of the PWAM-based single-phase qZS PV power system.

In this study, conventional dc/dc converters are integrated with a battery for renewable energy applications. The proposed battery-integrated dc/dc converters (BICs) can be compact size because these converters comprise just two switches and two diodes. Smaller size and desirable efficiency of the proposed BICs make it possible to use BICs in grid-connected (on-grid) distributed photovoltaic (PV) systems. The proposed BICs provide constant output power (less fluctuation) in different irradiance levels in distributed PV systems resulting in a constant output voltage at the connection point of BICs to the DC link. Besides extracting maximum power from the renewable source, output voltage is properly regulated on reference voltage in the proposed BICs. Depending on the utilisation states of the battery in grid-connected distributed PV systems, the operation of BICs is described in three scenarios. A linear quadratic regulator (LQR) control is applied to regulate output voltage and power of renewable source on references for three scenarios. Finally, the performance of the proposed BICs with LQR controller is verified by simulation (in PSCAD) and experimental results.

The sinusoidal modulation per phase and vector modulation are the most commonly employed pulse-width modulation techniques in three-phase inverters. There exist different schemes based on the variable switching frequency technique such as the hysteresis and finite control set based on the model predictive control with constant sampling period. This study proposes an alternative scheme by implementing a finite-control-set for a three-phase voltage-fed inverter. Here, a model solution-based control scheme is utilised, which allows the usage of a single controller resulting from the system simplification. It is shown that the proposed scheme exhibits an improved dynamic response under load variations and allows an easy digital implementation, which is the indication of its potential application from a practical point of view. A complete analysis and discussion of the proposed scheme as well as implementation and experimental results are provided to illustrate its effectiveness.

A novel transformer-less five-level (5L) high-voltage full-scale converter is proposed for 10 MW wind turbines. In this scheme, a unidirectional sinusoidal 5L-Vienna rectifier is used as a variable-speed controller at the generator side, and a conventional 5L neutral-point-clamped (NPC) inverter is used as the grid-integrated converter. The intrinsic dc-link NP imbalance issue is solved only by a proposed dc-link self-balance auxiliary circuit. This study focuses on the modulation technology of the rectifier and the operational principle of the auxiliary circuit. Furthermore, it presents a control strategy for the proposed converter. Finally, the small-scale experiments are carried out to verify the analysis.

The requirement of three-phase inverters with high reliability capability is considered important in several applications. Most of the adopted fault-tolerant solutions use classical three-phase voltage source inverters (VSI) with redundant controlled power devices or modified control strategies for acceptably degraded performance in the event of a failure yielding the loss of devices. This work proposes the use of a fault-tolerant converter based on the quasi-Z-source inverter (qZSI). This inverter presents important features such as boost capability and not requires dead time circuits. These features associated to the proposed topology results in a converter with high reliability and fault-tolerant capability. The proposed topology is designed to allow the reconfiguration of the converter after a power switch failure, using only two legs in the faulty mode. Additionally, this topology avoids extra inductors, capacitors and active power switches for the fault-tolerant condition. A current controller associated to a vectorial voltage modulator is used to control the proposed topology, which results in three-phase balanced AC currents with reduced total harmonic distortion even in faulty condition. The performance of this solution is confirmed through experimental results obtained from a laboratory prototype.

This study presents a novel generation scheme involving a single-phase induction generator capable of generating power utilising wide range of wind speeds for standalone domestic application. The variable excitation for the induction generator is provided by a single-phase bidirectional converter which has a battery and a photovoltaic (PV) panel across it. The excitation from the bidirectional converter is controlled using a direct voltage control based loop. The scheme uses dynamic voltage reference which is based on the speed of the turbine enabling the generator to operate for wide range of wind speeds. The PV panel connected to the DC bus of the converter is used during the daytime and the stored energy in battery can be used during night or low insolation periods. This adds to the reliability for the proposed scheme especially for standalone supply. Suitable simulations backed by experimental results validate the proposed concept.

This study describes the design and control of simplified structure of three-phase 4-level inverter. A 4-level dc-link derived from three symmetrical dc voltage supplies and two controlled switches is connected to a three-phase 3-level neutral point clamped (3-level NPC) bridge inverter. By employing the fundamental frequency switching technique, the simplified 4-level inverter can have two distinct modes of operation: 4-level and 2-level. Compared to the well-known three-phase 4-level NPC inverter, the proposed inverter topology comes with series of features including a minimum number of power components, high quality voltage waveform, lower losses and higher efficiency. To ensure the feasibility of the proposed topology with its suggested modulation technique, the prototype of the proposed 4-level inverter is built and the experimental results are given.

A medium-voltage high-power electric traction system, due to its non-linear nature results in serious power quality issues in power system such as low-power factor and high-harmonic distortion. To mitigate the aforementioned problems, this study presents a seven-level asymmetrical hybrid multilevel converter that can be implemented using a single dc source and two capacitors. The proposed converter is a series connection of a five-level cascaded module (CM) converter with an H-bridge cell to meet the demand of medium-voltage high-power traction applications with improved power factor at minimum harmonic distortion. A modulation scheme presented will operate an H-bridge cell and a CM with a fundamental frequency and high-frequency switching, respectively. The unbalancing of dc-link capacitors voltages due to active power transfer requires corrective control action including current control, voltage control and voltage balancing that has been proposed to keep the dc-link capacitor voltage balanced. Working principle of the proposed topology and its mathematical analysis is presented in this work. The effectiveness of the controlled pulse-width modulation strategy and stability of the proposed control method have been validated through simulation and experimental results.

We describe a method for simulating an electromagnetic induction type wireless power transmission (WPT) device. This simulator was based on the finite-difference, time-domain method. To reduce computation time, two graphics processing units (GPUs) were used as accelerators for the electromagnetic field computation. The first GPU calculated the electromagnetic field for the non-resonance state, and the second GPU calculated the field for the resonance state. Only two physical quantities needed to be exchanged between the two GPUs: self-inductance and the magnetic coupling coefficient. Capacitors and a load resistance were virtually connected to the coils as lumped elements. The experimental and simulation results were in good agreement. It is expected that a transient response analysis of WPT devices will become possible in the future using this simulation architecture.

The quasi-switched boost inverter (qSBI) has the advantage over the quasi-Z-source inverter (qZSI) in reducing one capacitor and one inductor. The qSBI is applied to the cascaded H-bridge (CHB) topology to create a new cascaded single-phase five-level inverter. Besides, a PID controller for DC-link voltage of each module is proposed and implemented based on DSP TMS320F28335. Unlike the DC-link voltage controller in qZSI, the presented controller is directly controlled via controlling the capacitor voltage. By using this controller, the capacitor voltage is kept constant, even though the input voltage or the load is changed suddenly. As a result, the proposed cascaded system solves the imbalance problem of DC-link voltage in the traditional CHB inverters. Also, a grid-connected control strategy for modules in the cascaded five-level qSBI is presented. The proposed inverter offers much less total harmonic distortion of the output voltage. Simulation and experimental results are shown to verify the validity of the proposed control strategy.

In this study, a new non-isolated six-phase interleaved boost dc–dc converter is presented for photovoltaic (PV) applications. The suggested structure consists of two symmetric three-phase interleaved boost dc–dc converters along with two switched-capacitor cells, in order to obtain high conversion ratio. For different values of duty-cycles, the voltage conversion ratio of the proposed topology is high. Also, the voltage stress of switches for various duty cycles is low and the efficiency of proposed topology is high. Moreover, the value of input current ripple is low with the utilisation of interleaving techniques. These advantages cause the proposed topology to be a good candidate for PV systems. The operation modes and mathematical analysis of the presented converter is introduced. In order to show the merits of presented converter, comparison results with other boost dc/dc converters are provided. Both experimental and simulation works based 453 W are presented to verify the operation of recommended converter. PSCAD/EMTDC software is used for simulation work.

This study deals with the performance analysis of three digital filters viz. multiple complex coefficient filter (MCCF), moving average (MA) and Butterworth in distribution static compensator (DSTATCOM) for non-linear loads. The filters are designed to extract the fundamental component of load current and tested in the closed-loop control of DSTATCOM. The filters are used to extract fundamental signal from the non-linear distorted source/load currents and all the lower-order harmonics present in the non-linear current drawn by the load. The performance of MCCF filter is compared to conventional filters such as Butterworth and MA filter. The detailed frequency response of MCCF is analysed. The magnitude and phase response plot of the MCCF suggest that this filter has unity gain and zero phase shift at fundamental frequency. All the three filters are implemented on a DSTATCOM for three-phase, three-wire distribution system. The DSTATCOM is implemented using a three-phase voltage source converter controlled using dSPACE 1104 controller. The closed-loop operation of DSTATCOM designed using MCCF is tested under steady state and dynamic system conditions. Simulation and experimental results are demonstrated with relevant waveforms under different load conditions.

A new interleaved high step-up DC–DC converter is presented in this study which integrates coupled inductors and voltage multipliers techniques into interleaved structure to provide high voltage gain without extreme duty cycle. The voltage stress across power metal–oxide–semiconductor field-effect transistors is very low, so low voltage rating switches with lower R _ds(on) can be used. A modified version of winding cross-coupled inductors technique is employed to minimise the input current ripple, and also the reverse recovery problem of the output diodes is alleviated because of the leakage inductance of the coupled inductors. Also, the leakage energy is absorbed and recycled to the output by the passive clamp scheme. In addition, automatic current sharing performance between the interleaved phases is established without any extra circuit. The operating principles of the proposed converter are explained and the theoretical analysis is provided, and in order to verify the effectiveness of the proposed converter, a 170 W, 30–360 V laboratory prototype is implemented.

To solve the problem that three-to-five-phase matrix converter (MC) cannot supply symmetrical voltages to unbalanced loads, a topology of five-phase six-bridge indirect MC and a carrier-based pulse-width modulation (PWM) method are proposed. A midline bridge is added to the neutral point of five-phase loads in inverter stage. The neutral point voltage is analysed and derived by space vector PWM (SVPWM) method for calculating the duty ratio of midline bridge. Calculations of other five-phase bridge duty ratios of SVPWM method remain unchanged. All of the duty ratios are used to calculate modulation waves of rectifier stage and inverter stage. Driving signals of two-stage power switches are generated by comparing the modulation waves with a carrier, which are used to control the neutral voltage as corresponding zero-sequence voltage. Therefore, five symmetrical output voltage sinusoids are obtained under both balanced and unbalanced loads. Finally, simulation and experimental results are provided to verify the feasibility and validity of the proposed method.

This study proposes a novel control strategy for a three-level active neutral-point clamped (3L-ANPC) inverter using selective harmonic elimination pulse width modulation (SHEPWM). The proposed control strategy can effectively control the neutral-point potential (NP) balancing and eliminate the selective harmonics simultaneously. The three-phase SHEPWM line-to-line voltages of the inverter are considered as switching-states. Among these switching states, the six pairs of redundant switching-states generate the same line-to-line voltages and thus the same harmonic spectrums with each pair having opposite effects on NP balancing. As a result, the pair of switching-states can be swapped to control the NP while still maintaining the same inverter output. The decision to make such swap will take into account directions of output currents, polarities of NP offsets and exclusion of directly switching between P and N states. The simulation and experimental results on a Matlab/Simulink model and prototype of a three-phase 3L-ANPC inverter are used to verify the effectiveness of the proposed control strategy.

The influence of the changes in load quantity on a multiple-receiver wireless power transfer (WPT) system should be minimised, so that the stability of received power for each load can be guaranteed. Here, a multiple-receiver WPT system with an series–series topology is compared with that with an inductance-capacitance-inductance-parallel (LCL-P) topology, and a WPT system with an LCL-P topology is selected to maintain the stability of load power. Then, the concept of effective working area is proposed. If the receivers are placed within the effective working area, the mutual inductances between receivers and transmitter are almost the same. Additionally, to realise the load detection method, which is convenient for system control purposes, reflection impedance theory is applied to detect the quantity of loads. Finally, the proposed circuit topology and detection method are practically verified in an experimental prototype.

A high-efficiency fully integrated 36 V–3 A stepping down DC–DC converter with high step-down ratio and predictive over-current protection scheme is introduced. To achieve high-voltage conversion ratio, emulated current mode and dedicated current sensing circuits were involved. A novel predictive over-current scheme is proposed to overcome inherent lack of emulated current-mode control and provide fast response to over-current events. In addition, due to N-type field effect transistor (NFET) was adopted to improve efficiency, a floating rail regulator is presented to generate bootstrapped voltage for driver stage. The proposed converter was simulated and fabricated in 0.18 μm bipolar-complementary metal–oxide–semiconductor (MOS)-double-diffused MOS process. Experimental results show the features work well, and with 35 ns minimum on-time, this converter can convert up to 36 V input voltage to 1.8 V at 1 MHz switching frequency with single stage and compact solution. Measured peak efficiency is 89.5% and over 80% efficiency for 3 A output current is realised as well.

Loss values are key parameters for designing high-performance high-frequency magnetic components for power electronics (PE) converters. With the increase of PE switching frequencies, copper losses have to be precisely quantified, ideally until some megahertz. In the literature, many 2D numerical simulations based on finite element analysis (FEA) are performed for such computations. 3D FEA studies of planar components are still limited because of modelling problems, computational resources and computing time. In this study, quantitative comparisons between 2D and 3D simulation results for planar inductors are achieved focusing on copper loss computation. Results are compared in terms of simulation performances and accuracy. The aim of the study is to highlight benefits of 2D and 3D FEA simulations in order to choose the appropriate model according to the studied problem.

Due to features of near-unity power factor, soft turn-off switching and low switch current stress, Cuk power factor correction (PFC) converter operating in discontinuous capacitor voltage mode (DCVM) has attracted much attention. However, it is found that with the increase of intermediate capacitance, slow-scale instability occurs in voltage mode control (VMC) DCVM Cuk PFC converter. In this study, a simplified model for VMC DCVM Cuk PFC converter is established, upon which the effect of intermediate capacitance on the slow-scale instability and the corresponding bifurcation behaviours are studied by using harmonic balance method and Floquet theory. Furthermore, the stability boundaries in terms of the intermediate capacitance under different load resistance and input voltage are given, which is helpful for parameter design of VMC DCVM Cuk PFC converter. Finally, numerical simulations and experimental results are provided to verify the analysis results.

This study deals with the development of a photovoltaic (PV) electronic emulator (PVEE), operating integrated with a graphic computing platform, for teaching topics related to PV systems in either undergraduate or postgraduate courses. The PVEE is deployed by a DC–DC buck converter to emulate on its output terminals several characteristic curves of a specific PV system, in which climate conditions such as solar irradiation and temperature are taken into account. Emulation of the PV module characteristic curves is embedded in a digital signal controller, which is based on a mathematical model that represents the electric circuit of the PV cell. The educational platform makes possible the following tasks: (i) define and change the PV cell model, (ii) define the number of PV modules, (iii) define and change the solar irradiation and temperature that the PV modules are subjected to, and (iv) visualise voltage and current quantities that are synthesised by the PVEE. From experimental tests, the PVEE is evaluated considering climatic variations involving solar irradiation, temperature, and load transients, whose purpose is to validate the theoretical development. Furthermore, the DC–DC boost converter is employed to perform the maximum power point tracking. Experimental results demonstrate the effectiveness of the proposed system.

This study presents an assorted carrier-variable frequency random pulse width modulation (AC-VF-RPWM) method in which a new type of mixed carrier wave is proposed for a three-phase voltage source inverter-fed induction motor drive. This study has focused on the reduction of acoustic noise where a deterministic PWM strategy is replaced with a proposed RPWM. Inverted sine carrier, sine carrier and triangle carrier are used to compare with the reference sinusoidal wave to generate the pulse (lead and lag) positions. The two groups (lead and lag) each with three pulse positions are randomly selected and it aims at dispersing the harmonic voltage over a wide band area. The linear feedback shift register-based random bit generation algorithms are used to select the three pulse positions from the lead and lag groups. In addition, a frequency modulator converts the carriers into a randomised frequency, which will give more potency to the randomisation process. The results of co-simulation and experimental evaluation that the proposed method could provide harmonic power spectra of the voltage and current spreading over a much broader band area, as compared with the conventional schemes. In addition, Xilinx XC3S500E FPGA device synthesis results are presented.

Hybrid DC breakers (HCBs) are crucial components in modern DC systems. Integrated gate-commutated thyristors (IGCTs) are widely used in high-voltage HCBs due to their controllable turn-off capabilities under high-power conditions. The focus of this study is on the optimisation of gate-commutated thyristors (GCTs) for HCB applications, including operation temperature and design parameters. The considerations of GCT design and operating conditions for the use in HCBs are discussed. Under those considerations, a 2D finite element model of GCT is developed to investigate the influence of the GCT design parameters on the maximum controllable current (MCC) and the safe operation area (SOA). Impedance unevenly distributed along the full wafer has been calculated to obtain accurate simulation results. Results show that the P⁺-base, lifetime, and the distance between cathode and gate metallisation can all affect the MCC. In addition, GCTs can provide a higher MCC by operating at a higher temperature.

One of the main problems in electric vehicles is the volume of their electrical systems because their bulky components carry additional mass and high cost to the total system. On this topic, interleaving-phases and magnetic coupling techniques have been reported as effective methods for increasing the power density of the DC–DC converters that work between the storage unit and the motor inverter. In that sense, a volume assessment of these topologies would provide a better understanding of the problems to be faced when an electric power train is designed. In this paper, a volume modelling methodology is introduced with the purpose of comparing four different DC–DC converters: Single-Phase Boost, Two-Phase Interleaved with non-coupled inductors, Loosely Coupled Inductor (LCI), and Integrated Winding Coupled Inductor (IWCI). The analysis considers the volume of magnetic components, power devices (conventional and next-generation), cooling devices and capacitors. The methodology can be used as a part of an optimization procedure to minimize the volume of DC–DC converters. Conclusively, LCI and IWCI were found effective to miniaturize power converters with a power density of 8.4 W/cc and 9.66 W/cc, respectively. Moreover, a maximum efficiency of 98.04% and 97.61% was obtained for a 1kW LCI and IWCI prototypes, respectively.