无电网电压传感器的直驱式风力发电系统建模及控制

Modeling and Control Strategy for Direct-drive Wind Power Generation Without Grid Voltage Sensors

直驱式风力发电系统使风力机与发电机之间直接相连,提高系统效率和可靠性。为此,采用了back-back的双PWM拓扑结构。机侧变换器采用间接转矩矢量控制,通过调节永磁同步发电机的转速,实现风能的最大跟踪;为了提高网侧并网逆变器的可靠性和抗电网电压波动,同时进一步降低并网逆变器的成本,提出了一种基于锁相环和虚拟电网磁链的无电网电压传感器的控制策略,并应用于直驱式风力发电系统中。仿真结果表明该控制策略实现了最大风能跟踪和并网逆变器功率因数为1的控制,从而验证了该方案的可行性和正确性。

A wind turbine is directly connected to a generator in the direct-drive wind power generation system to improve efficiency and reliability.The topology of back-back PWM was adopted.The indirect torque vector control was used for machine-side converters,which achieved the maximum wind power tracking by adjusting the speed of permanent magnet synchronous generator.In order to improve reliability and to resist grid voltage fluctuation,and to further reduce the cost for grid-connected inverters,a new method was proposed based on phase lock loop（PLL） and virtual grid flux without grid voltage sensors, which was applied in the direct-drive wind power generation system.The simulated results show that the control strategy realizes the maximum wind power tracking and the unity power factor,which verifies the feasibility and correctness for the control strategy.