小电容双PWM调速系统直流母线电压波动抑制策略

DC Bus Voltage Fluctuation Suppression Strategy for Small Capacitance Dual-PWM Speed Regulating System

现代船舶电动吊机广泛采用双侧脉宽调制交直交调速系统,但因其直流母线使用大容量电解电容使得系统不宜集成化且维修困难。该文在对系统小信号建模的基础上,提出一种采用小容量电容的控制策略。首先分析直流母线采用小电容时系统失稳原因,而后设计直流母线电压前馈补偿、d轴电流前馈补偿环节提高系统稳定性和带载能力,并结合二者优点得到小电容双PWM调速系统控制策略。以永磁同步电机作为负载的仿真和实验表明,该策略能保证系统稳定运行,可抑制转矩突变及脉动时的直流母线电压波动,对电网谐波注入较少且参数设计方法具有普适性。

Dual-PWM AC-DC-AC speed regulating system is widely used in modern Marine electric cranes.However,the system is not suitable for integration and maintenance because the DC bus uses large-capacity electrolytic capacitors.Based on the modeling of small signals,this paper presents a control strategy using small capacitance.Firstly,the reasons for system instability when the DC bus adopts small capacitors are analyzed.Then,the DC bus voltage feed-forward compensation and the d-axis current feed-forward compensation are designed to improve the system stability and load capacity.Combined with their advantages,the control strategy of small capacitance dual PWM speed regulation system is obtained.The simulation and experiment with permanent magnet synchronous motor as the load show that this strategy can ensure the stable operation of the system,restrain the voltage fluctuation of the DC bus during load sudden change and vibration,reduce the harmonic injection into the power network,and the parameter design method is universal.