反电动势过零检测无刷直流电机转子位置新方法  

A Novel Scheme of Sensing Rotor Position of BLDCM Based on the Zero-Crossing of Back EMF

作　　者：李自成[1,2] 程善美[1] 蔡凯[1] 秦忆[1] 

机构地区：[1]华中科技大学控制科学与工程系,武汉430074 [2]武汉工程大学电气信息学院,武汉430073

出　　处：《电工技术学报》2009年第7期52-58,共7页Transactions of China Electrotechnical Society

摘　　要：在对传统的反电动势过零检测原理分析的基础上,提出了一种利用线电压来实时计算反电动势的无刷直流电机(BLDCM)转子位置辨识方法。该方法抛弃了传统的反电动势过零硬件检测方法,通过检测无刷直流电机任意两路线电压,经软件实时计算,就可以得到未导通相的反电动势过零值,再延迟30°电角度即可得到对应的换相点。对电机中点与直流母线电压中点的电位关系进行了具体推导,分析了在全桥PWM调制方式下断开相在非换相区间无电流续流的现象,从而证明全桥PWM调制方法适用于本文提出的转子位置辨识方法。该方法结构简单,不需要构造电机中点、不需要反电动势过零硬件检测和深度滤波电路。仿真和实验结果表明,本文提出的方法辨识转子位置精度较高,可以在较宽的转速范围内实现BLDCM的无位置传感器控制。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.

关 键 词：反电动势 无位置传感器 无刷直流电机 换相 PWM 

分 类 号：TM381[电气工程—电机]