The brushless DC motor (BLDC motor) drive is used in several high performance applications ranging from servos to traction drives, due to several distinct advantages such as high power density, high efficiency, fast response and maintenance free. BLDC motor is usually driven by hard switching PWM inverter, which normally has higher switching losses. In recent years, these are several soft switching inverters presented. But there are many disadvantages such as high device voltage stress and large DC link voltage ripple and so on. This paper presents a transformer based resonant dc link inverter for brushless dc motor. The modulation strategies can be classified into two kinds according to the turn-off sequence of the two switches of the pair of switches. Here, dc link voltage notches during chopping switches commutation for all switches working in zero voltage switching condition. The operating principle of soft switching and control scheme are presented. The proposed scheme is verified with the simulation and experimental results.
Development of advanced PWM inverter with soft switching technique for brushless DC motor variable speed drives systems
