A New Zero-Voltage-Switching Push-Pull Converter

A soft switching three-transistor push-pull(TTPP)converter is proposed in this paper. The 3rd transistor is inserted in the primary side of a traditional push-pull converter. Two primitive transistors can achieve zero-voltage-switching (ZVS) easily under a wide load range, the 3rd transistor can also realize zero-voltage-switching assisted by leakage inductance. The rated voltage of the 3rd transistor is half of that of the main transistors. The operation theory is explained in detail. The soft-switching realization conditions are derived. An 800 W with 83.3 kHz switching frequency prototype has been built. The experimental result is provided to verify the analysis.

Widen the Zero-Voltage-Switching Range and Secure Grid Power Quality for An EV Charger Using Variable-Switching-Frequency Single-Dual-Phase-Shift Control

Compared to conventional electrical-vehicle(EV)on-board chargers utilizing a front-end Power-Factor-Correction(PFC)+an isolated DC/DC converter,which limits the wall-to-battery efficiency to~94%,a new control strategy using variable switching frequency(VSF)and variable phase shifts frees the PFC stage thereby getting rid of the DC link capacitor and further increasing the system efficiency and power density.The challenge is to secure zero-voltage-switching(ZVS)turn-on for all switches within the full-power range.In this paper a novel VSF single-dual-phase-shift(SDPS)control strategy is proposed,which consists of three control freedoms,i.e.,two phase shifts and one variable switching frequency to secure ZVS and achieve PFC simultaneously.ZVS boundaries are pictured and compared among single-phase-shift(SPS),dual-phase-shift(DPS)and the proposed single-dual-phase-shift(SDPS)control.Simulation results and experimental validation through a level-2 EV on-board charger indicate that by using the proposed SDPS control,both ZVS and PFC are secured not only for the heavy load but also for the light load,without sacrificing the system efficiency.

A dual VCDL DLL based gate driver for zero-voltage-switching DC-DC converter

This paper presents a dual voltage-controlled-delay-line（VCDL） delay-lock-loop（DLL） based gate driver for a zero-voltage-switching（ZVS） DC-DC converter.Using the delay difference of two VCDLs for the dead time control,the dual VCDL DLL is able to implement ZVS control with high accuracy while keeping good linearity performance of the DLL and low power consumption.The design is implemented in the CSM 2P4M 0.35μm CMOS process.The measurement results indicate that an efficiency improvement of 2%-4%is achieved over the load current range from 100 to 600 mA at 4 MHz switching frequency with 3.3 V input and 1.3 V output voltage.

SIMULATION AND EXPERIMENTATION OF THE ARC WELDING INVERTER USING THE SOFT SWITCHING TECHNIQUE

The FB-ZVZCS-PWM converter is realized by the way of subjoiningblock-capacitor into the FB-ZVS-PWM converter. At the freewheeling interval, the primary current isattenuated fast to zero and maintained. And then, power device of the static leg becomes azero-current-switch (ZCS), power device of the shifted leg becomes a zero-voltage-switch(ZVS). Thus,on one hand IGBT (Insulated gate bipolar transistor) with tail current can be easily used infull-bridge soft-switching converter; on the other hand additional circuiting energy is greatlyreduced. At the same time, less duty cycle loss, lower secondary parasitic resonance, widersoft-switching load range can be achieved. Based on the existing component models in the Pspicesoftware package, a combined model of IGBT is established, in which a non-linear capacitor isintroduced to replace the parasitic capacitor. Using this model, computerized simulation isconducted for the FB-ZVZCS-PWM soft-switching converter, the switching and energy-transferringcharacteristics of the power device are analyzed. Finally, based on the achievement above, a 10 kWarc welding inverter with FB-ZVZCS-PWM converter is developed. The simulation results are testifiedby experiments. It is proved that by adopting appropriate models, computerized simulation is aneffective and useful tool for the development of the arc welding inverter.

Principle and parameter design of arc welding inverter using soft switching technique

The soft switching are welding inverter reduces switching losses and improves operating environment of devices by using Zero-Voltage-Transition (ZVT) technique. Step-by-step analysis of each timing interval and the associating voltage and current waveforms are included for the Full-Bridge Zero-Voltage-Switched PWM converter. Numerous design equations supporting the phase-shifted soft switching technique are highlighted.

SVM strategy and analysis of a three-phase quasi-Z-source inverter with high voltage transmission ratio

Herein,we propose a novel three-phase quasi-Z-source inverter with a high voltage transmission ratio to address challenges such as high switching loss and sizeable magnetic components in the basic quasi-Z-source inverter.The proposed circuit topology,control strategy,and related analysis are presented.The circuit topology of the inverter comprises a quasi-Z-source network with an integrated magnetic inductor,an active clamp circuit,a three-phase inverter bridge,and an output LC filter,all of which are connected in series.An improved 12-sector space vector modulation scheme is proposed based on the root-mean-square value of the voltage and the instantaneous value of the current.Furthermore,analyses of the inverter voltage transmission ratio,resonant process,and parametric design guidelines for integrated magnetic inductor and zero-voltage switching conditions are presented.Experimental results on a 1-kVA prototype inverter demonstrate that the proposed inverter exhibits a higher transmission ratio and efficiency than existing inverters;thus,the proposed inverter would have broad prospects in low-voltage DC-AC applications.