An Optimized Zero-Voltage Zero-Current Transition Boost Converter Realized by Coupled Inductor

This paper proposes a new high-gain soft-switching dc–dc topology based on a switched inductor boost converter (SIBC). A conventional SIBC as a high gain boost topology has the issues of high conduction loss in switching diodes and high switching loss in the main switches. Also, it has severe electromagnetic interference (EMI) issue due to high-frequency ringing formed by parasitic inductance and diode junction capacitors. The new topology is derived with the objective of achieving zero voltage switching (ZVS) turn on of the main switch. Instead of adding extra active clamp zero voltage transition (ZVT) path at the switching node, the proposed topology augments the auxiliary ZVT path to the switching diode path. This is achieved by replacing the switching diodes with synchronous switches. The new topology can achieve soft switching for all the switches and alleviate the EMI issue. All the diodes achieve zero current switching (ZCS) turn off without reverse recovery. Auxiliary switches have ZCS turn on and ZVS turn off , and the main switches have ZVS turn on . The soft-switching SIBC also reduces the conduction loss in the switching diodes. A numerical simulation in PLECS and a prototype hardware are built corresponding to a micro-inverter application with 100 kHz switching frequency. Peak power conversion efficiency of 94.76% is achieved in the hardware prototype with Si devices.

In this paper, a new ZVT-PWM DC-DC boost converter is proposed. In the proposed new converter, the main switch turns on under Zero Voltage Transition (ZVT) and turns off under Zero Voltage Switching (ZVS). Besides, the auxiliary switch turns on under Zero Current Switching (ZCS) and turns off under Zero Current Transition (ZCT). Also, the other semiconductor elements softly turn on and turn off under ZVS or ZCS. Another feature of proposed converter is that there is no additional current or voltage stress on the main switch and main diode. Also, there is no additional voltage stress on the auxiliary switch and the auxiliary diodes. The proposed new converter operates even under light load conditions and it has advantages as the simple structure, the low cost and easy control. Firstly, the theoretical analysis of the proposed converter is made. Then, the operating stages, the key waveforms and the simulation results of the new converter operated for 500 W and 40 kHz is given in detail.

This study presents an improved zero voltage switching (ZVS) boost converter with an active snubber cell providing soft switched operation for all semiconductors. The active snubber cell reduces the reverse recovery loss of the boost diode and also provides the zero voltage transition (ZVT) Turn-on and ZVS Turn-off for the boost switch. The zero current switching (ZCS) Turn-on and ZVS Turn-off for the snubber switch is also achieved. All diodes in the converter can be operated with soft switching (SS). In the snubber cell, SS energy can be transfered effectively to the output by the use of a snubber inductor and a capacitor. This energy transfer allows the use of additional parallel connected capacitor to the boost switch to provide ZVS turning off. There is no additional voltage and current stress on the boost switch and boost diode. The voltage stress of the snubber switch is also limited by the output voltage and the current stress of the snubber switch is reduced by the energy transfer to the output. SS operating of the semiconductors is maintained at very wide load ranges. The operation of the proposed converter is presented with a detailed steady state analysis. The predicted theoretical analysis is validated by a prototype with 500[Formula: see text]W output power and 100[Formula: see text]kHz operating frequency. The measured maximum efficiency values are obtained as approximately 97% and 85.4% at full load and 10% load conditions, respectively.

In this study, a new zero-voltage transition (ZVT)–zero-current transition (ZCT) quasi-resonant buck converter, which ensures zero crossings at any time required for soft switching (SS) and provides ZVT turn-on and ZCT turn-off together for the main switch of active snubber cell in buck converter is presented. The proposed circuit combines the most of the advantageous features of the circuits presented previously and overcomes most of drawbacks of these circuits by using only one auxiliary switch with fewer other components. Consequently, new ZVT–ZCT quasi-resonant buck converter, which is verified by a prototype of a 0.4-kW and 100-kHz circuit, is analysed in detail. All semiconductor devices operate under SS, the main switch is subjected to no additional voltage and current stresses, and the stress on the auxiliary switch is very low in the proposed new converter.

This paper presents a new soft switching (SS) multiphase interleaved boost converter (MIBC) consisting of three boost converters (BCs) that operate rapidly and efficiently to charge a lithium-ion battery for photovoltaic (PV) power system applications. This suggested converter can operate both active power switches at zero current switching (ZCS), and when switched off, it works at zero voltage switching (ZVS), which reduces switching losses and increases switching efficiency (SF). An interleaving structure is employed to decrease the conduction losses and reduce the input current ripple (ICR) and output voltage ripple (OVR) to increase the power rating. The suggested converter regulates the input and output power by modulating the phase shift in the pulse width modulation (PWM) technique using the maximum power point tracking (MPPT) algorithm via two closed feedback loops, one for a slower external loop and the other for a faster PWM control internal loop, similar to current mode control. The suggested converter has high voltage (HV) gain due to the coupled inductors (CIs), which act as a transformer. This magnetic design structure in both the steady-state and transient states also decreases the size and enhances the converter’s performance. Finally, the suggested converter was experimentally verified on a 285W prototype, and the maximum efficiency was found to be 98%, based on modeling and experimental data.

본 논문에서는 영전압 스위칭(ZVS)과 전류불연속 모드(DCM)에 의한 새로운 고효율의 DC-DC 컨버터에 대해 연구된다. 일반적으로 고효율의 컨버터를 만들기 위해서는 전력변환기내에 사용된 반도체 스위칭 소자의 손실을 최소화하여 이루어진다. 제안한 컨버터는 DCM에 의하여 스위치의 턴-온 동작을 영전류 스위칭(ZCS)으로 만들고, 또한 새로운 유사공진 회로를 접목하여 컨버터의 고효율을 실현시킨다. 제안한 컨버터에 사용된 제어용 스위칭 소자들은 유사공진 기법에 의해 소프트 스위칭, 즉 ZVS와 ZCS으로 동작시키고, 이에 따른 제어용 스위칭 소자들은 전압과 전류의 스트레스 없이 동작한다. 그 결과 제안한 컨버터는 스위칭 손실의 저감에 의해 고효율로 구동된다. 제안한 DCM-ZVS 컨버터의 소프트 스위칭 동작과 시스템 효율은 디지털 시뮬레이션과 실험결과를 통해 그 타당성이 입증된다. This paper is study on a new high efficiency DC-DC converter of discontinuous conduction mode (DCM) with zero voltage switching (ZVS). The converters of high efficiency are generally made that the power loss of the used semiconductor switching devices is minimized. The proposed converter is accomplished that the turn-on operation of switches is on zero current switching (ZCS) by DCM. The converter is also applicable to a new quasi-resonant circuit to achieve high efficiency converter. The control switches using in the converter are operated with soft switching, that is, ZVS and ZCS by quasi-resonant method. The control switches are operated without increasing their voltage and current stresses by the soft switching technology. The result is that the switching loss is very low and the efficiency of the converter is high. The soft switching operation and the system efficiency of the proposed DCM-ZVS converter are verified by digital simulation and experimental results.

The resonant commutated twin pole inverter (RCTPI), a novel resonant pole inverter topology using only main switches, is introduced. One phase of a voltage source RCTPI consists of four switches arranged in two symmetric half-bridges called the twin poles. Each pole carries half of the phase current. The switches are turned off as zero voltage switch (ZVS) and zero current switch (ZCS) respectively and turned on under ZCS both. Switching losses in the semiconductor devices can be reduced in all operating points by soft switching, while overall losses are reduced only at high load currents. The concept can be realised using IGBTs in standard packages. Single switch modules, half- and full-bridge modules and some six-packs are suitable - this is an advantage compared to many other resonant topologies.

The traditional variable-timing control of auxiliary resonant snubber inverter (ARSI) realize natural zero-voltage-switching (ZVS) of main switches in every switching period to reduce the conduction loss. However, this method leads to failure of ZVS in the light load condition. Therefore, this paper proposes an improved control scheme with two modes for single-phase ARSI to achieve ZVS from zero load to full load. In heavy load mode (HLM), half of main switches are turned on at ZVS condition by using the output current to reduce the conduction loss. In light load mode (LLM), all the main switches achieve ZVS with the conduction of resonant branch to solve the problem of the failure of ZVS near zero load current. Besides, the auxiliary switches can operate at zero-current-switching (ZCS) condition. The proposed control scheme was first verified in the simulation and then validated in the experiment with an inverter prototype. The results show that the proposed control scheme can make main switches achieve ZVS from zero load to full load.

A soft-switching active snubber is proposed to reduce the turn-off losses of the insulated gate bipolar transistor (IGBT) in a buck power converter. The soft-switching snubber provides zero-voltage switching for the IGBT, thereby reducing its high turn-off losses due to the current tailing. The proposed snubber uses an auxiliary switch to discharge the snubber capacitor. This auxiliary switch also operates at zero-voltage and zero-current switching. The size of the auxiliary switch compared to the main switch makes this snubber a good alternative to the conventional snubber or even to passive low-loss snubbers. The use of the soft-switching active snubber permits the IGBT to operate at high frequencies with an improved RBSOA. In the experimental results reported for a 1 kW, 40 kHz prototype, combined switching/snubbing losses are reduced by 36% through the use of the active snubber compared to a conventional RCD snubber. The use of an active snubber allows recovery of part of the energy stored in the snubber capacitor during turn-off. The generic snubber cell for the buck power converter is generalized to support the common nonisolated DC/DC power converters (buck, boost, buck-boost, Cuk, sepic, zeta) as well as isolated DC/DC power converters (forward, flyback, Cuk, and sepic).

A soft switching boost converter, with a small number of components and constant frequency control, is proposed herein by using the quasi-resonance method and the zero-voltage-transition method, realizing (1) the zero-voltage switching during the switch-on transient of the main switch, (2) the zero-current switching during the switch-off transient of the main switch, (3) the zero-current switching during the switch-on transient of the auxiliary switch, and (4) the zero-current switching during the switch-off transient of the auxiliary switch. Accordingly, the corresponding efficiency can be improved. The feasibility and effectiveness of the proposed structure are validated by the field programmable gate array (FPGA).

Two new soft-switching converters for switched reluctance motor drives are proposed and analyzed. The proposed zero-voltage-transition (ZVT) converter possesses the definite advantages that both main transistors and diodes can operate with zero-voltage switching (ZVS), as well as unity device voltage and current stresses. On the other hand, the proposed zero-current-transition (ZCT) converter offers the advantages that both the main and auxiliary switches operate with zero-current switching (ZCS), as well as minimum current and voltage stresses. Both converters have the merits of simple circuit topology, minimum component count and low cost.

Here, a new active snubber cell for high-power isolated pulse-width-modulated (PWM) DC–DC converters is proposed. All semiconductor power devices in the proposed converters operate with full soft switching under a very wide load range, and they are not exposed to any voltage and current stress. The main switches turn on with zero-voltage transition (ZVT) and turn off with zero-voltage switching (ZVS). The auxiliary switches turn on with zero-current switching (ZCS) and turn off with ZVS. The theoretical analysis and design procedure for the proposed active snubber cell are carried out in detail and are verified with a half-bridge (HB) converter implementation having 20V output voltage, 50 A output current, and 80 kHz switching frequency. The overall efficiency of the HB DC–DC converter is increased from about 83% in the hard switching condition to about 90% thanks to the proposed active snubber cell.

This paper proposes a new zero-current switching (ZCS) pulse width modulation (PWM) switch cell that has no additional conduction loss of the main switch. In this cell, the main switch and the auxiliary switch turn on and turn off under zero current condition. The diodes commutate softly and the reverse recovery problems are alleviated. The conduction loss and the current stress of the main switch are minimized, since the resonating current for the soft switching does not flow through the main switch. Based on the proposed ZCS PWM switch cell, a new family of DC to DC PWM power converters is derived. The new family of ZCS PWM converters is suitable for the high power applications employing IGBTs. Among the new family of DC to DC PWM converters, a boost converter was taken as an example and has been analyzed. Design guidelines with a design example are described and verified by experimental results from the 2.5 kW prototype boost converter operating at 40 kHz.

In this paper, an improved Zero-Voltage-Transition (ZVT) two-cell interleaved boost Power Factor Correction (PFC) converter is proposed and investigated. A new auxiliary circuit is designed and added to two-cell interleaved boost converter to reduce the switching losses. Only one auxiliary switch is used in the active soft switching auxiliary circuit. The main advantage of this auxiliary circuit is that it not only provides ZVT in the boost switches but also provides soft switching in the auxiliary switch and passive diodes. Therefore, the switching losses of the converter can be reduced. Compared to the previous published soft switching interleaved boost converters, only one auxiliary switch is needed in the auxiliary unit, so the auxiliary unit and control circuit are simple. A 1kW, 50 kHz two-cell interleaved boost PFC converter with an improved ZVT auxiliary circuit has been simulated using average current control method and the results are presented. Simulation results show that the main switches, the auxiliary switch and passive diodes are operating under soft switching mode.

This research introduces a coupled inductor-based high gain non-isolated DC-DC converter for DC microgrid systems. A coupled inductor and a voltage multiplier circuit are used to provide high gain at a low duty ratio. The main side interleaving lowers the source current ripple. An active clamp auxiliary resonant circuit was included in the converter's primary switches for soft switching. To reduce switching losses, Zero Voltage Switching (ZVS) turn-ON and Zero Current Switching (ZCS) turn-OFF are achieved. The voltage quadrupler circuit for the proposed converter has ZCS turn-OFF on all of the diodes. The voltage stress on all MOSFETs and diodes has been significantly reduced, further reducing loss during switch conduction and increasing the converter's efficiency. This proposed theoretical concept is validated through simulation at 200kHz, which converts 24 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$V$</tex> to 400 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$V$</tex> .