LC滤波器对电机速度闭环控制的影响分析和设计方法研究

Influence of LC Filter on Motor Velocity-Loop Control and an LC Filter Design Method

速度闭环回路被广泛应用于光电跟踪系统的转台电机的驱动控制。良好的电机速度闭环响应特性可以有效提高光电系统对目标的跟踪精度。转台电机是通过逆变放大器输出的脉宽调制(PWM)电压进行驱动的。随着光电跟踪系统的性能要求和电磁兼容性需求的不断提高,必须使用逆变器输出滤波器对PWM驱动电压所造成的电磁噪声干扰进行抑制。传统上,滤波器的设计方法是通过提高其插入损耗加强对电磁噪声的抑制,但对滤波器给电机控制造成的影响分析不足。针对该问题,深入研究了具有代表性的LC滤波器对电机速度闭环控制的影响。建立了存在滤波器时的电机被控对象特性模型,并分析了其传递函数特性。提出了一种在不降低LC滤波器插入损耗的前提下,减小其对速度闭环控制影响的滤波器设计方法,并通过光电吊舱的速度闭环控制实验证明了所提方法的有效性。

Velocity-loop control is widely used in the electro-optical tracking system for motor driving.Good velocity-loop response is helpful to improve the tracking accuracy of the electro-optical system.The motor of the system is driven by the Pulse Width Modulation(PWM) voltage outputted by the inverter.As the demand for accuracy and electro-magnetic compatibility of the electro-optical tracking system is increasing, inverter output filter must be used to suppress the electro-magnetic noises caused by PWM voltage.Traditionally,the design of the filter enhances electro-magnetic noise suppression based on the improvement of insertion loss,but the analysis of the impact of the filter on motor control is inadequate.To solve the problem,the influence of LC filter on the motor velocity-loop control is studied.The plant model of the motor with an LC filter is established,and the transfer function of the plant is given.A new design method of LC filter is proposed,which can reduce the influence on motor velocity-loop control as well as maintaining the insertion loss.Experiments on the velocity-loop control of electro-optical pod are conducted to verify the effectiveness of the proposed method.