一种适用于光伏并网发电系统的高增益ZVT交错并联Boost变换器

本文提出了一种新型的有源交错并联ZVT软开关电路，该电路是在普通交错并联Boost变换器的基础上增加耦合电感绕组和有源箝位辅助单元形成。耦合电感绕组的引入扩展了变换器的电压增益和减小了开关管的电压应力，因此减小了开关管导通损耗。耦合电感的漏感限制了输出二极管关断电流的下降率，抑止了二极管的反向恢复，大大减小了反向恢复电流引起的损耗。有源辅助开关和吸收电容组成的辅助电路吸收并无损的转移了漏感能量，消除了主开关管上的电压尖峰。在整个开关周期内，主管和辅助管都是零电压开关，大大减小了开关损耗。最后，设计了一台40V输入、380V输出的1kW试验样机。仿真和试验结果表明，所有的功率器件均为软开关工作，本电路特别适用于光伏发电系统中低电压输入、高电压输出的前段变换。

A High Step-Up ZVT Interleaved Boost Converter for Photovoltaic Grid-Connected System

A ZVT interleaved Boost converter is proposed for high step-up conversion. The coupled inductor is employed to achieve high voltage gain and reduce the voltage stress of the switches. The active clamp circuit composed of a switch and a small capacitor is adopted to absorb the voltage spikes on the main switches and recycle the leakage energy. During the whole switching transition, both the main switches and the auxiliary switches are ZVT soft switching. The output diode reverse-recovery problem is alleviated significantly by the leakage inductance. So the reverse-recovery losses are reduced and the EMI noise is suppressed. The proposed converter is suitable for low-voltage-input high-voltage-output of the photovoltaic grid-connected system. A prototype with 40V-to-380V rated at 1kW has been built to verify the effectiveness of the circuit.