用于无刷直流电机驱动的谐振极软开关逆变器

用硬开关逆变器来驱动无刷直流电机会产生逆变器的开关损耗大和运行效率低的问题。为降低开关损耗,提出一种用于无刷直流电机驱动的新型谐振极软开关逆变器的拓扑结构,通过在传统硬开关逆变器的三相输出端添加辅助谐振电路,利用辅助电路中的高频变压器的等效电感与主开关并联的缓冲电容之间的谐振,实现逆变器主开关器件的零电压开关和辅助开关器件的零电流开关。依据不同工作模式下的等效电路图,分析了电路的换流过程和设计规则,并建立起了辅助谐振电路损耗的数学模型,讨论了谐振参数对辅助电路损耗的影响。制作了1台实验样机,实验结果表明逆变器的主开关和辅助开关都实现了软开关。该谐振极软开关逆变器能有效改善效率,降低开关损耗。

A resonant pole soft-switching inverter for brushless DC motor drives

The brushless DC motor is supplied by a hard-switching inverter,which causes the problem of high switching loss and low efficiency in the inverter.A resonant pole soft-switching inverter was proposed for brushless dc motor to reduce switching loss.By adding auxiliary resonant circuits to three-phase out-put of the hard-switching inverter,it realized zero voltage switching operation of all main switching devices in inverter and zero current switching operation of auxiliary switching devices,based on the resonance be-tween the equivalent inductance of high frequency transformer in the auxiliary circuit and snubber capaci-tor in parallel with main switching device.According to equivalent circuits in different modes,commuta-tion process of the circuit and design rule were analyzed.The mathematical model for auxiliary resonant circuit loss was established and the influence of resonant parameters on the loss of auxiliary circuit was discussed.A laboratory prototype was built.Experimental results showed that both of the main switching devices and auxiliary switching devices were operated under zero voltage or zero current.The resonant pole inverter presented can effectively improve efficiency and reduce switching loss.