Novel Resonant DC Link Soft Switching Inverter for Brushless DC Motor Drive System

Brushless DC motor (BLDCM) has been widely used in drive systems and servo control because of its fast response, high power density and high efficiency and so on. It is usually driven by a hard-switching PWM inverter, which has low switching frequency, high switching loss, high electro magnetic interference (EMI) and acoustic noise, etc. To solve the drawbacks of the voltage source type hard switching inverter, many types of resonant DC link inverters have been widely studied. However, these inverters have such drawbacks as high voltage stress of the devices, delta modulation, threshold limit of inductor current or capacitor voltage and sophisticated control. This paper proposed a novel zero voltage transition parallel resonant DC link voltage source inverter (ZVT-PRDCL-VSI) for BLDCM drive systems. The inverter possess advantages of low switching power loss, low inductor power loss, small device voltage stress, simple control scheme and no unbalancing problem of neutral-point voltage. The operation principle and control scheme of the inverter are analyzed. The validity of the circuit is verified by simulation and experimental results.