双PWM全功率变流器机侧控制策略研究

双脉宽调制(PWM)全功率变流器机侧的开关频率低,其电流谐波含量高,且同步电机反电动势中产生了大量谐波.为了降低发电机的铜铁损耗,降低系统成本,弱化网侧滤波器设计的难度,抑制机侧谐波具有重要意义.传统比例积分(PI)调节器难以抑制直驱永磁同步发电系统机侧谐波,针对这一现象,提出将PI与准比例谐振(PR)调节器联合,形成新型的调节器,并在转子定向的旋转坐标系下对定子电流特定次谐波进行了抑制.运用PSCAD/EMTDC软件进行了仿真验证,结果表明:采用经典PI控制时,机侧电流谐波含量为17.28%;采用新型调节器时,机侧电流谐波含量为5.86%.同时,通过分析实验结果验证了该机侧控制策略的可行性,可有效地抑制机侧谐波.

Study on the Motor-side Control Strategy of Dual PWM Full Power Converter

The switching frequency of dual pulse width modulation (PWM) converter with full power in motor-side was low.Its current harmonic content was high.Furthermore, a large number of harmonics were generated in the back EMF of synchronous motor.It was very important to restrain the harmonics of the motor side to reduce the copper loss, the iron loss, the system cost and the difficulty of the filter design of the network side.It was difficult for the traditional PI controller to restrain the harmonics of direct-driven wind turbine with permanent magnet synchronous generator (D-PMSG).Therefore, a new control strategy of the motor-side converter was proposed based on the combination of proportional integral(PI) regulator and quasi proportional resonant(PR) regulator to suppress the specific harmonic of stator current in the rotor oriented rotating coordinate.The simulation was conducted with the software PSCAD/EMTDC.The current harmonic content of the motor-side was 17.28% with traditional PI controller, while it was 5.86% with the proposed controller.The feasibility of the motor-side control strategy was validated by the experimental results.