永磁伺服系统电流环带宽扩展研究

分析了数字控制系统中延迟的产生原因和影响因素。基于永磁同步电机数学模型，建立了加入数字控制系统延迟的永磁伺服系统电流环数学模型。分析了电流环带宽与电流采样和PWM更新时序之间的关系。针对改进即时更新方式在开关器件的开关频率变高的情况下采样延迟比增加、带宽提升效果下降的问题，提出了一种基于开关状态的电流延迟补偿分段式PWM更新方式。该方法相比于传统电流更新方式对处理器性能要求更低，对使用了宽禁带开关器件的伺服系统同样适用。实验验证了该方法的可行性，相比于传统采样更新方式该方法可以将电流环带宽提高10倍。

Study on Bandwidth Expansion of Current Loop in PMSM Servo System

The causes and influencing factors of delay in digital control system are analyzed. Based on the mathematical model of permanent magnet synchronous motor, the current loop mathematical model of permanent magnet servo system with digital control system delay is established. The relationship between current loop bandwidth and current sampling and PWM update sequence is analyzed. To improve the instant update method, a current delay compensation piecewise PWM update method based on switching state is presented, which can increase the sampling delay ratio and decrease the bandwidth enhancement effect when the switching frequency of switching devices is higher. This method requires less processor performance than traditional current update methods, and is also applicable to servo systems using wide band-gap switch devices. Experiments verify the feasibility of this method, which can increase the bandwidth of current loop by 10 times compared with the traditional sampling update method.