A novel scheme of sensing rotor position of BLDCM based on the zero-crossing of back EMF

作者：Li Zicheng^*; Cheng Shanmei; Cai Kai; Qin Yi

来源：Transactions of China Electrotechnical Society, 2009, 24(7): 52-58.

• Back EMF
• BLDCM
• Commutation
• PWM
• Sensorless control

A novel method of rotor position identification of brushless DC motor (BLDCM) is proposed by line voltage calculation based on the traditional zero-crossing of back EMF. The unexcited phase back EMF signal is indirectly obtained from line voltage calculation instead of traditional hardware sensing method. The real commutation point is the zero-crossing of back EMF shifted by 30°. The relationship between motor neutral voltage and half DC voltage is detailedly analyzed. In the double switch PWM scheme, the diode freewheeling currents in the unexcited phase are eliminated completely so that double switch PWM strategy is available for proposed rotor position estimation scheme. This method is simple to implement without the need to sense or reconstruct the motor neutral. Neither hardware circuit of sensing back EMF nor depth filter circuit is needed. Simulation and experimental results verify the validity of the proposed scheme of sufficient identification accuracy in a wide speed range.

• 出版日期2009
• 单位华中科技大学