基于改进型滑模观测器与旋转高频电压注入法的永磁同步电机无传感器矢量控制(下)

永磁同步电机的无传感器矢量控制,其本质在于不使用位置检测传感器,只通过检测电机的定子电压、定子电流来估算转子的位置,进而实现转子磁场定向控制,也就是矢量控制。目前估算方法,工程上普遍采用的是滑模观测器法,但是滑模观测器法在电机低速运行时的转子位置估算精度很低,即便电机运行在中高速段,由于系统的惯性、状态变量的估算误差等因素,导致电机带载运行时存在高频抖动现象。为了弥补滑模观测器法的上述缺陷,提出了一种基于改进型滑模观测器与旋转高频电压注入法的永磁同步电机无传感器矢量控制算法,电机低速运转时使用旋转高频电压注入法以提高转子位置估算精度,中高速运转时使用改进型滑模观测器法以克服高频抖动。上述算法在一台额定功率为45kW的三相凸极永磁同步电机上得以成功运用,试验结果验证了所提出的控制算法的有效性。

Sensorless Vector Control of Permanent Magnet Synchronous Motor Based on Improved Sliding Mode Observer and Rotating High Frequency Voltage Injection Method

The essence of the sensorless vector control of permanent magnet synchronous motor(PMSM) is that the position detection sensor is not used, the rotor position is estimated only by detecting the stator voltage and current of the motor, and then the rotor magnetic field orientation control, which is vector control, is carried out. At present, the estimation method is generally adopted by the sliding mode observer(SMO) method, but the estimation precision of the rotor position is very low when the motor is running at low speed. Even if the motor runs in the middle and high speed section, due to inertia of the system, or the estimation error of state variables, etc, high frequency torque ripple is inevitible. In order to make up the above defects of sliding mode observer, a sensorless vector control algorithm for permanent magnet synchronous motor based on rotating high frequency voltage injection and improved sliding mode observer was proposed. The rotating high frequency voltage injection method was used to improve the accuracy of the rotor position estimation when the motor is running at low speed. The sliding mode observer method was used to overcome the torque ripple. The proposed algorithm was successfully applied to a three-phase salient permanent magnet synchronous motor whose rated power is 45kW, and the experimental results verify the effectiveness of the proposed control algorithm.