电流型PWM整流器多环控制策略及其参数设计

A Multi-loop Control Strategy and Parameter Design for Current-source PWM Rectifiers

通过对三相脉宽调制电流型整流器(current source rectifier,CSR)的分析,利用前馈解耦控制策略,建立了d-q坐标系下多环控制的线性大信号数学模型。为了有效抑制整流器输入侧电感–电容滤波器产生的并联谐振,文中引入电容电压反馈有源阻尼控制环路。基于频域法对含有源阻尼控制、延迟环节的电流内环进行分析,并辅助Matlab中单输入–单输出设计工具,优化内环控制器零点位置与环路增益,以兼顾系统动态响应与稳定性。由于电流外环与运行工作点有关,针对电池组容性负载,该文提出电流外环开关选择控制器,根据负载电动势并依照所制定的映射法则,选择相应的控制器参数,从而改善系统在宽范围运行时的性能。最后,通过计算机仿真和实验样机测试,验证了该文所提出的控制方法与参数设计,不仅使三相CSR系统表现出良好的动、静态性能,而且在宽输出电压、电流变化范围内,能够保持单位功率因数以及较低的网侧电流畸变。

By analyzing the system of three-phase pulse width modulation （PWM） current-source rectifiers （CSR）, and with feed-forward decoupling method in d-q reference frame, a linear large-signal model based on the multi-loop current controller was established in this paper. Meanwhile, as an alternative approach for active damping, capacitor-voltage feedback was used to suppress the inductor-capacitor filter （LC） resonance. Therefore, the transfer function of the inner current loop was analyzed using the frequency-response method, by considering the effect of system control delay and active damping compensation. By using the Matlab/$ISO design tool, the zero position and loop gain of the inner loop controller were optimized with a compromise between dynamic response and stability of the controller. Due to the gain of the outer loop transfer function is always dependent on the operating point of the CSR, an outer current selector switch controller was proposed, and the controller was selected according to the load voltage value and the mapping rules. Finally, simulation and experimental results demonstrate that the proposed control Strategy and parameter design not only have excellent dynamic and stability performances, but also can achieve unity input displacement power factor and can reduce the input-current distortion in a wide range of output voltages or currents.