Zero-voltage transition–zero-current transition pulsewidth modulation DC–DC buck converter with zero-voltage switching–zero-current switching auxiliary circuit

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.

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.

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.

A new family of zero-voltage transition (ZVT) pulse width modulation (PWM) converters is introduced. In this converter family there is no additional voltage stress on the main switch in comparison to the hard switching counterpart. Also, the voltage and current rating of the auxiliary switch is low. The proposed zero-voltage transition PWM buck converter is analysed and design considerations are discussed. A prototype converter is implemented and the experimental results are presented.

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.

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.

This paper proposes an interleaved zero voltage transition (ZVT) PWM buck converter. The proposed converter consists of two identical buck converter modules and an auxiliary circuit. The auxiliary circuit provides zero voltage switching condition for the main switches. Also, zero current switching condition for the auxiliary switch and diodes is achieved. The interleaved buck converter with the proposed auxiliary switch is analyzed. The simulation results of a 300W ZVT interleaved buck converter operating at 100 KHz are presented to justify the validity of theoretical analysis.

In this paper, a new zero-voltage zero-current transition (ZVZCT) boost converter using coupled inductors is proposed. The feature of this topology is: the main switch can be switched on with ZVZCT, and off with zero-voltage switching, without any voltage and current stress. The auxiliary switch is turned on with zero-current switching. Other semiconductor devices can also achieve soft switching (SS). Due to the existence of the coupling effect, the current impact of the auxiliary switch is completely suppressed when it is turned off . Lower input current and output voltage in the interval of the switch- off for the auxiliary switch are just equivalent to running at a low power level, which is an additional advantage of the coupled inductor ZVZCT solution. Another advantage of the topology is that the SS condition of the main switch for each specific load can be effectively optimized just by setting the ratio of coupling inductance corresponding to the circuit design and application load. Thus, the topology design can be improved to adapt to different load types. A 100 kHz experimental prototype has been verified, different load for 1 and 0.4 kW optimization comparison has been presented, and the case without optimization is also observed.

A new reduced voltage stress soft switching PWM current fed Full-Bridge DC-DC converter for fuel cells and photovoltaic cells applications is proposed in this study. The snubber cell provides Zero Voltage Transition (ZVT) turn on and Zero Voltage Switching (ZVS) turn off together for main switches in the converter. The voltage stresses of the main the switches are reduced and turning them off became better by adding an extra passive component. Besides, all components operate under soft switching, the current or voltage stresses on the auxiliary component are quite in acceptable level, and the main devices do not have any additional current stresses. In addition, the simplified structure makes the novel converter easy to control. Detailed analysis and synthesis of the new converter is introduced, and usefulness of the design is confirmed by simulation studies of a 1.5 kW and 25 kHz full bridge converter.

This study presents a zero‐voltage‐transition (ZVT) bridgeless power factor correction (PFC) rectifier, which uses an auxiliary circuit with a transformer to achieve soft‐switching for the main power switches. With the auxiliary circuit, the main switches can be ZVT turned‐on without any additional voltage or current stresses. In addition, the auxiliary switch is turned‐off with zero‐current switching. Therefore, the switching loss of all power switches is reduced, and the overall rectifier efficiency is improved. The circuit topology, operation analysis and the components selection of the proposed rectifier are described in detail. Finally, a laboratory prototype of 700 W is implemented and tested to verify the performance of the proposed PFC rectifier.

In order to minimize the losses in high frequency converters such as the Quasi-Resonant (QR) Buck converter, the Zero Voltage Switching (ZVS) technique is used. Quasi-resonant Buck converters are implanted by adding reactive elements to conventional topologies, and the addition of an extra capacitor and inductor regarding the switch of a Buck converter. Such technologies nowadays are widely used as power supplies for certain battery chargers. A ZVS QR Buck converter is proposed in this paper. After having reminded the principle of operation of a classic ZVS QR Buck converter. Some simulations results are performed in SIMPLORER and ISIS soft-wares to validate the proposed ZVS QR Buck converter. Experimental results has been made on a laboratory prototype. Experimental results obtained on a laboratory prototype are presented to verify the

In this paper, a new soft switching T-type three level inverter is proposed. The proposed new converter provides for main switches to turn on with Zero Voltage Transition (ZVT) and turn off with Zero Voltage Switching (ZVS) without any voltage or current stresses. Also, the proposed new converter provides Soft Switching (SS) for all semiconductors. Besides, Electro Magnetic Interference (EMI) noises are decreased by soft switching cell. The proposed converter has a low cost, ease of control and simple structure. The theoretical analysis of converter is clarified and the operating stages are given in detail. The simulation results of converter are obtained for 3.3 kW and 50 kHz by PSIM program. It is observed that the simulation results and theoretical analysis of converter are perfectly suitable with each other.

An improved soft switching dual-switch forward converter topology is proposed in this paper. Compared with conventional dual-switch forward converter, the proposed converter employs an auxiliary switch and a clamp capacitor to instead of two reset diodes. Therefore, its duty cycle can exceed 0.5 to achieve wide range input voltage, also soft switching can be achieved for all switches. Especially, voltage stress across main switches can be clamped at 1/2Vin, voltage stress across auxiliary switch can be clamped at Vin. In addition, due to clamp capacitor series with the transformer, duty ratio can be extended with equation Vo = {Vin(1-D)D}/N. Thus, as a kind of better cost-effective approach, it is very attractive for high input, wide range and high efficiency application.

In this study, a zero voltage transition (ZVT)–zero current transition (ZCT) pulse‐width modulated (PWM) multiphase synchronous buck converter (SBC), with an active auxiliary circuit is proposed, that reduces the stresses and enhances the efficiency abating the switching and conduction losses of the converter. The important design feature of ZVT–ZCT PWM multiphase SBC converters is the placement of resonant components that pacifies the switching and conduction losses. Due to the ZVT–ZCT, the resonant components with low values are used that results in the increase of switching frequency. High current multiphase buck converters found applications in the advanced data control, solid state lasers, communication equipment, Pentium processors etc. The ZVT–ZCT operation of the proposed converter is presented through theoretical analysis. A simple design method for the auxiliary circuit is discussed. The characteristics of the proposed converter are verified with the simulation in the PSIM co‐simulated with MATLAB/SIMULINK environment and validated with experimental results.

In this paper, a new modular‐isolated‐forward‐based active snubber cell (SC) for power switches is designed. In the proposed new SC, the zero voltage transition (ZVT) technique is implemented with a forward converter although the current counterparts generally use a flyback converter. In the converter with the new SC, the main switch is turned on with ZVT (full zero voltage switching [ZVS]) and turned off with ZVS, the main diode is turned off with zero current switching (ZCS), the auxiliary switch is turned on with ZCS and turned off with ZVS, and the parasitic capacitor energies are recovered. In addition, thanks to the forward converter, it has been possible to minimize the transformer leakage inductance and greatly reduce the current values of devices in the new SC. The new cell is applied to a single‐phase, grid‐connected, T‐type three‐level inverter (T2‐3LI) as an example. A detailed steady‐state analysis of this inverter was made, and the theoretical analysis was confirmed with measurement results taken from a prototype with 100 kHz and 3.3 kW values. Compared to its hard switching (HS) equivalent, in the converter with soft switching (SS) cell, the total circuit loss was reduced from about 248 W to 86 W, thus achieving an increase in the total efficiency from 92.5% to 97.4%.