基于无源性理论的双馈风力发电机双PWM变换器协调控制

Passivity-based co-operation control of dual PWM converters for doubly-fed wind power generator

交流励磁双馈风力发电系统在实现最大风能跟踪过程中,转子侧功率变化频繁,使得双PWM变换器中的直流母线电压波动剧烈。基于无源性理论提出了一种双PWM变换器的协调控制方案,对双PWM变换器的转子侧和电网侧分别进行直接功率控制,使其具有相同的动态响应特性;在电容电压反馈控制的基础上引入功率前馈控制,使电容两侧功率流动动态平衡,以减少电容电压的波动。建立了双PWM变换器励磁的双馈风力发电系统的仿真模型,仿真结果表明该协调控制策略极大地改善了直流母线电压的动态特性,实现了最大风能跟踪,并且降低了变换器中电容容量要求,提高了风电系统的电能质量。

During the maximum wind power capture of the doubly-fed wind power generator excited by the dual PWM conveter,the power of the rotor windings varies frquently and fiercely,which leads to the voltage fluctuation of the DC bus.Direct power control of the rotor-side and the grid-side converters individually are suggested.A new passivity-based co-operation control strategy is put forward for the dual PWM converter,so the subsystem can has the same dayamic characteristics.Power forward control is introduced to the voltage feedback control of the capacitor,so the power flows of the two sides of the capacitor keep balanced,which alleviates the voltage variation of the capacitor.The simulation model is established for the doubly-fed wind power generation system excited by the dual PWM converter.Simulation results show that the control strategy can not only realize the maximum wind power capture,but also improve the dynamic voltage characteristics of the DC bus.The controller designed reduces the capacity requirement of the capacitor and enhances the electric quality of the system.