含LCL滤波的测功用永磁同步发电机电流控制策略

Current Control Strategy for Permanent Magnet Synchronous Generator With LCL Filter Used in Power Measuring System

永磁同步电力测功机系统将永磁同步发电机通过PWM整流器实现能量回馈,相比于传统的功率吸收型测功机节约大量能源,其电流精确控制技术值得研究。近年来LCL型滤波器被广泛用于电压源型PWM整流器滤波,其控制策略备受关注。为了提高由LCL滤波的永磁同步发电机电流控制系统性能,文章提出一种整流器侧电流反馈加电动势前馈补偿的电流控制策略。首先建立了由LCL滤波的三相永磁同步发电机PWM整流发电系统的数学模型,然后对LCL滤波器的整流器侧电流反馈有源阻尼控制进行了分析,接着提出了有电动势微分前馈的整流器侧电流反馈的定子电流控制策略,最后通过Simulink仿真验证了所提出的控制策略。仿真结果表明所提出的控制策略能够很好的抑制永磁同步发电机的定子电流谐波,提高了电流控制的精度,保证发电机很高的功率因数输出。

The permanent magnet synchronous generator（ PMSG） dynamometer system connect PMSG with PWM converter to feedback generating energy. The system save much energy compared with conventional dynamometer which transfer generating energy to heat energy. So,research on exact current control technology for this type system is necessary. Recent years,LCL filters are widely used for voltage source converter（ VSC） to attenuate switching harmonics caused by the pulse width modulation（ PWM） switching and the control strategy for it attract much attention. In order to improve the performance of the permanent magnet synchronous generator（ PMSG） current control system filtered by LCL,this paper proposed a current control strategy by converter side current feedback and electromotive force feedforward compensation. The continuous system model including LCL filter,PWM converter and three phase PMSG was established. The active damping method by converter side current feedback was analyzed in frequency domain. Based on the analysis,a current control strategy by converter side current feedback with derivation of electromotive force feedforward compensation was put forward and validated by numerical simulation using Matlab / Simulink. The simulation results demonstrate that the proposed control strategy is able to suppress high order harmonics of winding current effectively and improve control precision of current amplitude and phase,ensuring that the generator has high power-factor.