MP-MMC驱动六相永磁同步风力发电机分数阶PID控制研究

Research on fractional order PID control of six phase permanent magnet wind turbine driven by MP-MMC

针对多相模块化多电平变流器(MP-MMC)驱动多相发电机,在Y移30度六相永磁同步发电机(PMSG)旋转坐标系下的数学模型基础上,引入了分数阶PID控制器。分数阶PID控制器相比整数阶PID控制器增加了两个控制自由度,即主要影响控制系统稳态性能的积分阶次λ和主要影响控制系统动态性能的微分阶次μ,使得分数阶PID控制器的设计更加灵活。在MMC内部能量均分部分采用分数阶PID控制器可使得子模块电容电压峰峰值及其谐波畸变率降低,进而输出电压波形得到改善;也使得MMC的桥臂环流峰峰值降低,环流波形得到改善。在发电机转速侧,发电机定子的d、q轴电流闭环控制侧部分采用分数阶PID控制器可使发电机转速动态性能与稳态性能进一步改善。在z1和z2子空间的谐波分量控制部分采用分数阶PID控制器可使得系统谐波影响更小,控制效果更佳。最后,仿真和实验结果验证了分数阶PID控制器具有良好的控制性能,可进一步提升了六相PMSG-MMC系统的运行能力。

For multi-phase modular multilevel converter(MP-MMC) to drive multi-phase generator, a fractional order PID controller is introduced based on the mathematical model under the rotating coordinate system of the six-phase permanent magnet synchronous generator with winding shifted-phase 30 degrees. Compared with the integer order PID controller, the fractional order PID controller increases two control degrees of freedom, that is, the integral order λ which mainly affects the steady-state performance of the control system and the differential order μ which mainly affects the dynamic performance of the control system, making the design of the fractional order PID controller more flexible. Using fractional order PID controllers in the internal energy sharing part of MMC can reduce the voltage peak-to-peak of the sub-module and its harmonic distortion rate, and then improve the output voltage waveform. It also reduces the bridge arm circulating current peak to peak value of MMC and improves the circulating current waveform. The fractional order PID controllers were used in the generator speed side and the d-axis and q-axis current closed-loop control side of the generator stator, which can further improve the dynamic and steady-state performance of the generator speed. The fractional order PID controllers were used in the harmonic component control part of z1and z2subspaces, which can make the harmonic influence of the system smaller and the control effect better. Finally, the simulation and experimental results verify that the fractional order PID controller has good control performance, which can further improve the operation ability of the six phase PMSG-MMC system.