改进的滑模观测器实现PMSM无传感器控制

Sensorless Control of PMSM Realized by an Improved Sliding Mode Observer

无传感器控制技术能提高永磁同步电机驱动系统可靠性、环境适应性,且降低系统成本。基于一阶滑模观测器的无位置控制系统中,低通滤波器提取反电动势时,将产生相位延迟和幅值衰减,常需相位补偿环节。随着转速降低,补偿环节的补偿作用变差,位置估计误差增大,带载能力大大下降;且现场应用中,理想的补偿系数不易得到,系统调试难度较大。针对该问题,提出用自适应复数滤波器替代低通滤波器的无位置控制实现方法。自适应复数滤波器具有零相移、无衰减的优良特性,能在较宽速域内实现反电动势的精确提取,故无需相位补偿环节。仿真和实验结果表明,所提策略简化了系统结构、大大提升了带载能力,且系统颤振不再随转速降低而增大,而呈现等颤振水平。

Sensorless control technology can improve the reliability and environmental adaptability of PMSM drive system,and reduce the cost of system.In the sensorless control system based on first-order sliding mode observer,phase delay and amplitude attenuation will occur with low pass filter extracting back EMF,and phase compensation is usually needed.With the decrease of speed,the compensation function of compensation link becomes worse,the estimated position error increases,and the load capacity decreases greatly.Moreover,in the field application,the ideal compensation coefficient is not easy to obtain,thus the system is difficult to debug.To solve this problem,the way of realizing sensorless control was proposed,in which a self-adapting complex filter was used to replace the low pass filter.The adaptive complex filter has the advantage of zero phase shift and no amplitude attenuation.It can accurately extract the back EMF in the wide speed range,and phase compensation is not needed any more.The simulation and experimental results illustrate that the proposed strategy simplifies the structure of the system,improves the load capacity greatly.Furthermore,the system chattering no longer increases with the decrease of speed,but presents an equal chattering level.