Novel zero-voltage and zero-current-switching (ZVZCS) full-bridge PWM converter using coupled output inductor

A novel zero-voltage and zero-current-switching (ZVZCS) full-bridge pulse-width-modulated (PWM) converter is proposed to improve the previously proposed ZVZCS full-bridge PWM converters. By employing a simple auxiliary circuit with neither lossy components nor active switches, soft-switching of the primary switches is achieved. The proposed converter has many advantages such as simple auxiliary circuit, high efficiency, low voltage stress of the rectifier diode and self-adjustment of the circulating current, which make the proposed converter attractive for the high voltage and high power applications. The principles of operation and design considerations are presented and verified on the 4 kW experimental converter operating at 80 kHz.     

采用辅助变压器的零电压零电流开关全桥直-直变换器

本文给出了一种新型的零电压零电流开关全桥移相脉宽调制变换器,该变换器采用IGBT为功率开关管,在传统变换器的基础上通过增加辅助变压器的方式提高了变换器的性能,通过增加正激能量恢复缓冲器和辅助电路,使变换器在各种负载以及短路工作状态下都能够保证所有开关管实现零电压零电流开关工作模式。介绍了变换器的工作原理并通过试验得到了较好的结果。     

Novel zero-voltage and zero-current-switching full bridge PWMconverter using transformer auxiliary winding

A novel zero voltage and zero current switching (ZVZCS) full bridge (FB) pulse width modulation (PWM) converter is proposed to improve the demerits of the previously presented ZVZCS-FB-PWM converters, such as use of lossy components or additional active switches. A simple auxiliary circuit which includes neither lossy components nor active switches provides ZVZCS conditions to primary switches, ZVS for leading-leg switches and ZCS for lagging-leg switches. Many advantages including simple circuit topology, high efficiency, and low cost make the new converter attractive for high power (>2 kW) applications. The operation, analysis, features and design considerations are illustrated and verified on a 2.5 kW, 100 kHz insulated gate bipolar transistor (IGBT) based experimental circuit     

A zero-voltage and zero-current switching three-level DC/DC converter

This paper presents a novel zero-voltage and zero-current switching (ZVZCS) three-level DC/DC converter. This converter overcomes the drawbacks presented by the conventional zero-voltage switching (ZVS) three-level converter, such as high circulating energy, severe parasitic ringing on the rectifier diodes, and limited ZVS load range for the inner switches. The converter presented in this paper uses a phase-shift control with a flying capacitor in the primary side to achieve ZVS for the outer switches. Additionally, the converter uses an auxiliary circuit to reset the primary current during the freewheeling stage to achieve zero-current switching (ZCS) for the inner switches. The principle of operation and the DC characteristics of the new converter are analyzed and verified on a 6 kW, 100 kHz experimental prototype.     

Zero-voltage and zero-current-switching full-bridge PWM converterusing secondary active clamp

A new zero-voltage and zero-current-switching (ZVZCS) full-bridge (FB) pulse width modulation (PWM) power converter is proposed to improve the performance of the previously presented ZVZCS FB PWM power converters. By adding a secondary active clamp and controlling the clamp switch moderately, ZVS (for leading-leg switches) and ZCS (for lagging-leg switches) are achieved without adding any lossy components or the saturable reactor. Many advantages, including simple circuit topology, high efficiency and low cost, make the new power converter attractive for high-voltage and high-power (>10 kW) applications. The principle of operation is explained and analyzed. The features and design considerations of the new power converter are also illustrated and verified on a 1.8 kW 100 kHz IGBT-based experimental circuit     

A novel zero-Voltage and zero-current-switching full-bridge PWM converter

A novel zero-voltage and zero-current-switching (ZVZCS) full-bridge pulse-width modulation converter is proposed. The ZCS condition of the lagging-leg is obtained by a simple secondary auxiliary circuit resetting the primary current during the freewheeling stage. The auxiliary circuit's capacitor is charged by the center tape of the secondary through a diode, and the capacitor's voltage is clamped through another diode to output capacitor, thus, the voltage stress on the rectifier is clamped. There are neither additional active switches nor resistances in the auxiliary circuit, which makes the proposed converter efficient.     

Zero-voltage and zero-current switching full bridge DC-DC converterfor arc welding machines

A new zero voltage and zero current switching (ZVZCS) full bridge DC-DC converter with transformer isolation is proposed for arc welding machines. The proposed DC-DC converter uses an auxiliary transformer to obtain ZCS for the leading leg, which provides load current control capability even under short circuit conditions. The power rating of the auxiliary transformer is ~10% or more of the main transformer. The operation is verified by experiments     

一种新型的零电压零电流三电平变换器的研究

针对采用IGBT的软开关三电平变换器中IGBT关断过程存在的电流拖尾现象,以及基本三电平拓扑变压器次级存在的电压过冲和电压振荡现象,提出了改进型ZVZCS三电平结构。该结构在基于拓扑的三电平桥臂侧和两电平桥臂侧分别加入了一个无源辅助网络,三电平桥臂侧的辅助变压器在续流阶段为主变压器初级电流回零提供了条件,两电平桥臂的谐振电感和箍位二极管有效地抑制了主变压器次级电压的过冲现象。详细分析了改进拓扑的工作原理、工作模态,以及辅助网络的工作特点,并研制了实验样机,验证了理论分析的正确性以及改进拓扑的可行性。     

Family of Zero-Current Transition PWM Converters

In this paper, a new auxiliary circuit is introduced for applying to buck, buck-boost, zeta, forward, and flyback converters. This auxiliary circuit provides a zero-current switching condition for all switching elements. The proposed zero-current transition (ZCT) pulsewidth-modulated buck converter is briefly described. Also, a ZCT flyback converter is analyzed, and its different operating modes are presented. Design considerations are explained, and a design example along with the experimental results of the ZCT flyback converter is presented.     

一种全桥ZVZCS DC/DC变换器的研究

提出了一种全桥零电压零电流(FB-ZVZCS)DC/DC变换器拓扑,副边采用电容和二极管构成了两个辅助电路,它们与谐振电感谐振形成的阻断电压源相串联,实现了滞后臂较大范围的ZCS,同时此种结构抑制了副边整流二极管尖峰电压;针对高输出电压设计,输出采用双全桥串联整流电路以降低整流二极管的高电压应力和解决它们的均压问题。变换器控制简单、没有辅助开关和缓冲电路。文中详细分析了工作原理和参数设计,仿真和样机实验验证了方案的正确性。     

基于UC3875的ZVZCS—PWM全桥变换控制器的研究

文中提出了一种新型次级箝位零电压、零电流变换器,分析了所提出的新型次级箝位ZVZCS电路拓扑的工作原理,详细论述了以UC3875为核心的控制器的设计及各参数的选择。最后给出了仿真及样机实验结果,进一步说明了控制器的设计及参数选择的合理性。     

A zero-voltage-switched PWM boost converter with an energyfeedforward auxiliary circuit

A zero-voltage-switched (ZVS) pulsewidth-modulated (PWM) boost converter with an energy feedforward auxiliary circuit is proposed in this paper. The auxiliary circuit, which is a resonant circuit consisting of a switch and passive components, ensures that the converter's main switch and boost diode operate with soft switching. This converter can function with PWM control because the auxiliary resonant circuit operates for a small fraction of the switching cycle. Since the auxiliary circuit is a resonant circuit, the auxiliary switch itself has both a soft turn on and turn off, resulting in reduced switching losses and electromagnetic interference (EMI). This is unlike other proposed ZVS boost converters with auxiliary circuits where the auxiliary switch has a hard turn off. Peak switch stresses are only slightly higher than those found in a conventional PWM boost converter because part of the energy that would otherwise circulate in the auxiliary circuit and drastically increase peak switch stresses is fed to the load. In this paper, the operation of the converter is explained and analyzed, design guidelines are given, and experimental results obtained from a prototype are presented. The proposed converter is found to be about 2%-3% more efficient than the conventional PWM boost converter     

A ZVZCS PWM FB DC/DC converter using a modified energy-recovery snubber

The conventional high-frequency phase-shifted zero-voltage-switching (ZVS) full-bridge DC/DC converter has a disadvantage, in that a circulating current flows through transformer and switching devices during the freewheeling interval. Due to this circulating current, RMS current stress, conduction losses of the transformer and switching devices are increased. To alleviate this problem, this paper proposes an improved zero-voltage zero-current switching (ZVZCS) phase-shifted full-bridge (FB) DC/DC converter with a modified energy-recovery snubber (ERS) attached at the secondary side of transformer. Also, the small signal model of the proposed ZVZCS FB DC/DC converter is derived by incorporating the effects introduced by a transformer leakage inductance and an ERS to achieve ZVZCS. Both analysis and experiment are performed to verify the proposed topology by implementing a 7-kW (120 VDC, 58 A) 30-kHz insulated-gate-bipolar-transistor-based experimental circuit.     

Novel zero-voltage-transition PWM multiphase converters

Novel zero-voltage-transition (ZVT) pulse-width-modulation (PWM) multiphase converters are presented. To construct a ZVT multiphase converter in a conventional way, it is necessary to add the auxiliary circuits with as many number of phases. In the proposed converter, only one auxiliary circuit provides the zero-voltage switching (ZVS) for main switches and diodes of all phases. So, the new converters are cost effective and attractive for high-performance and high power-density conversion applications. Operation, features, and characteristics of the two-phase buck converter are illustrated and verified on a 4-kW 100-kHz insulated gate bipolar transistor (IGBT)-based (a MOSFET for the auxiliary switch) experimental circuit     

Zero-Voltage Transition Current-Fed Full-Bridge PWM Converter

In this paper, a new zero-voltage transition current-fed full-bridge converter with a simple auxiliary circuit is introduced for high step-up applications. In this converter, for the main switches, zero-voltage switching condition is achieved at wide load range. Furthermore, all semiconductor devices of the employed simple auxiliary circuit are fully soft switched. The proposed converter is analyzed and a prototype is implemented. The experimental results presented confirm the validity of the theoretical analysis. Finally, the proposed auxiliary circuit is applied to other current-fed topologies such as current-fed push-pull and half-bridge converters to provide soft switching.     

Novel zero-voltage-transition current-fed full-bridge PWM converterfor 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     

移相全桥ZVZCS变换器及数字控制研究

针对利用变压器辅助绕组实现的移相全桥ZVZCS软开关电路，提出了一种基于DSP的数字控制方法，实现了移相全桥ZVZCS电路的数字化控制，分析了电路的工作原理，详细介绍了电路的数字化控制方案。通过一台2．5kW的DC/DC变换器实验样机对该方案进行了验证。     

基于有效占空比的ZVZCS全桥变换器建模与仿真

分析了零电压-零电流开关(ZVZCS)全桥脉宽调制(PWM)变换器的工作原理,引入变压器副边电压有效占空比的概念并考虑电路元件的寄生参数,在Buck变换器的PWM开关等效模型的基础上,建立了ZVZCS全桥软开关变换器的小信号等效模型,该方法通用于任何可以计算出有效占空比的全桥变换器.通过对小信号传递函数的幅频和相频特性...     

A simple active auxiliary commutation circuit for three-level PWMsingle-phase inverters

This paper presents the analysis and design of a new low-loss auxiliary circuit for three-level pulsewidth-modulation single-phase full-bridge inverters which achieve soft switching at all semiconductor devices. The active auxiliary commutation circuit (AACC) is composed of an LC circuit and two bidirectional switches, where one auxiliary switch commutates under zero-voltage switching condition and the other under zero-current switching condition. The AACC dispenses with the use of auxiliary voltage sources. Low reactive energy is added to the converter, resulting in low RMS current stresses at the main switches and, consequently, higher efficiency is achieved. Auxiliary circuit design procedures and experimental results are presented to prove the operation principle     

A self-driven active clamp forward converter using the auxiliary winding of the power transformer

This study proposes a new self-driven active clamp forward converter eliminating the extra drive circuit for the active clamp switch. The converter used the auxiliary winding of the power transformer to drive the active clamp switch and a simple RC circuit to get the dead time between the two switches. The operation principle was presented and experimental results were used to verify theoretical predictions. A 100-W (5 V/20 A) prototype converter that only exhibited 1.5-turn winding number in the auxiliary winding was sufficient to drive the active clamp switch on the input of 50 V. Finally, the measured efficiency of the converter was presented and the maximum efficiency of 91% was obtained.