辅助电路与主开关并联的单相全桥节能逆变器

为了改善逆变器的性能，提出了一种辅助电路与主开关并联的单相全桥节能逆变器.逆变器采用受限单极式正弦脉宽调制（Sinusoidal Pulse Width Modulation，SPWM）方法，在每个开关周期，只需要控制1个主开关和1个辅助开关的切换，辅助开关可以采用固定占空比控制，而且不需要设定谐振电流阈值来控制辅助开关.在每个开关周期的换流过程中，需要切换的主开关所并联的谐振电容的电压能变化到零，主开关能实现零电压软开通.辅助电路中无器件直接串联在直流母线上，可有效降低辅助电路通态损耗.分析了电路工作原理，实验结果表明主开关和辅助开关都实现了软切换.因此该拓扑能有效降低开关损耗和提高逆变器效率.

A Single-Phase Full-Bridge Energy-Saving Inverter with Auxiliary Circuits in Parallel with Main Switches

In order to improve performance of the inverter,a single-phase full bridge energy-saving inverter with auxiliary circuits in parallel with main switches is proposed.Limited monopole SPWM(Sinusoidal Pulse Width Modulation) is applied in the inverter.Only one main switch and one auxiliary switch need be controlled in every switching period.The duty cycle of the auxiliary switch is constant.Setting threshold of resonant current need not be designed to control the auxiliary switch.During the process of commutation in every switching period,the voltage across the resonant capacitor in parallel with the main switch decreases to zero and zero-voltage turning-on of the main switch can be achieved.All the components in the auxiliary circuit are not in series with DC(Direct current) bus,which can effectively reduce the conduction loss of auxiliary circuit.The working principle is analyzed in detail,and the experimental results show that the main switch and auxiliary switch can realize soft-switching.Therefore,the topology can effectively reduce the switching losses and improve efficiency of the inverter.