Zero-voltage Transition Converter Research Articles

High step-up ZVT Converter Based on Active switched Coupled inductors

To meet the requirements of high voltage boosting and high efficiency, a novel high step-up zero voltage transition (ZVT) DC/DC converter based on active switched-inductor (ASL) is proposed. This converter combines ASL and coupled inductor structure, thus can reduce the voltage and current stress of power switch, and the active clamping technology provides zero voltage transition (ZVT) for all switches. The coupled inductors can realize relatively high voltage gain with appropriate turns ratio while all magnetic components can be integrated in one core. In addition, thanks to the leakage inductance, the reverse recovery problem of diodes is resolved. The working principle of the proposed converter is analyzed in detail, also the characteristics including voltage gain, the condition of ZVT is discussed. Then, a family of derived converters are listed and compared to each other. According to the proposed converter, a 500W prototype with 100kHz switching frequency is established in the lab, and the experimental results are given to verify the analysis.

개선된 AC/DC PFC ZVT Boost 컨버터

본 논문에서는 보조 스위치의 하드 스위칭 문제를 개선한 AC/DC PFC(Power-Factor-Correction) ZVT(Zero-Voltage-Transition) Boost 컨버터에 관하여 논하였다. 기존의 AC/DC PFC ZVT Boost 컨버터는 주 스위치 턴온 시 보조 스위치를 함께 동작시켜 경부하시에도 강제적으로 영전압 스위칭이 가능하게 함으로써 전 부하범위에서 주 스위치 손실을 저감하였다. 그러나 보조 스위치에서의 손실이 크며 주 스위치의 턴온시 역방향 전류가 증가하는 문제점을 지닌다. 따라서 본 연구에서는 기존의 ZVT 컨버터에 단지 하나의 다이오드를 추가함으로써 보조 스위치의 전류 스트레스 및 주 스위치의 턴온시 역방향 전류를 감소시키게 되어 효율 향상을 기할 수 있었다. 본 논문에서는 MOSFET를 사용하여 640[W]급 시작품을 제작, 100[kHz]에서 실험하였다. This paper presents the improved AC/DC PFC(Power-Factor-Correction) ZVT(Zero-Voltage-Transition) Boost Converter. The conventional AC/DC PFC ZVT Boost Converter minimizes the switching loss of the main switch within all of the load range. That is because AC/DC PFC ZVT Boost converter makes the main switch and the auxiliary switch turn on simultaneously so that it makes ZVS (Zero-Voltage-Switching) possible at the light load. However, it has two problems that ale large loss of the auxiliary switch and the increasing of the reverse current of the main switch. Therefore this research presents high efficiency to reduce the current stress of the auxiliary switch and the reverse current of main switch by adding a diode to the conventional ZVT converter. The prototype of 640[W], 100[kHz] system using MOSFET is implemented for this experimental verification.

LARGE-SIGNAL ANALYSIS AND SIMULATION OF A ZVT BOOST CONVERTER

Large-signal analysis of a zero-voltage transition (ZVT) boost converter is presented. The proposed ZVT converter uses an auxiliary circuit with two auxiliary switches both having ZVS. Analysis is used to study the converter behavior for step changes in input voltage and load using MATLAB. SPICE simulation results are presented to verify the theoretical results. It is shown that the main switch and auxiliary switches of the proposed converter maintains soft-switching for large-signal transients.

A new two-quadrant zero-voltage transition converter for DC motor drives

A new zero-voltage-transition (ZVT) two-quadrant (2Q) converter for DC motor drives is presented. It possesses the definite advantage that both main switches and diodes can operate with zero-voltage switching in both motoring and regenerating modes, while both of these switches are subjected only to unity voltage and current stresses, namely the same as their PWM counterpart. This converter is particularly useful for DC traction systems in which both motoring and regenerative braking are desired to have high efficiency. The corresponding theoretical analysis and its high-efficiency performance are verified by both simulation and experimental results.

Novel zero-voltage-transition current-fed full-bridge PWM converter for single-stage power factor correction

A novel zero-voltage-transition (ZVT) current-fed full-bridge pulsewidth modulation (PWM) power converter for single-stage power factor correction (PFC) is presented to improve the performance of the previously presented ZVT converter. A simple auxiliary circuit which includes only one active switch provides a zero-voltage-switching (ZVS) condition to all semiconductor devices (two active switches are required for the previous ZVT converter). This leads to reduced cost and a simplified control circuit compared to the previous ZVT converter. The ZVS is achieved for wide line and load ranges with minimum device voltage and current stresses. Operation principle, control strategy and features of the proposed power converter are presented and verified by the experimental results from a 1.5 kW 100 kHz laboratory prototype.

Zero-voltage transition converter with high efficiency operating at constant switching frequency

A new type of zero-voltage-transition pulsewidth modulation (PWM) dc-dc converter is developed by adding two active switches and three diodes to the structure of a quasiresonant converter. The resonant capacitors are not discrete elements, their role is played by the parasitic capacitances of the MOSFETs. By adjusting the interval between the operation of the active switches, a duty-cycle control is obtained. Soft-switching is ensured for all switches for a wide line range and load range. One of the additional diodes is connected in the input circuit and the energy flow in the resonant stage is transferred from a path defined by the two additional transistors to a path given by the two additional diodes in the resonant tank; as a result, the resonant capacitor voltage is prevented from surpassing the input voltage; it drops to zero before the main switch is turned on. All switches are subjected to voltage and current stresses like those in their PWM classical counterparts, implying small conduction losses. The new converter exhibits a high efficiency and good regulation capability.