光伏发电系统利用直流 异步电机并网控制方法的研究

摘要

针对光伏并网逆变器存在成本高、故障率高、谐波含量大及控制复杂等问题,提出了一种实用的光伏发电系统利用直流 异步电机并网的方案. 该光伏并网系统中直流电机和笼型异步电机同轴旋转,实现直流电能和交流电能之间的转换. 由光伏电源为直流电机供电,直流电机拖动异步电机完成电机的起动过程;当电机转速接近同步速时并网开关合闸,实现光伏发电系统的并网运行. 光伏系统并网后,通过调节直流电机的端电压实现对异步电机输出有功功率的控制,保证直流母线电压的稳定. 在MATLAB/Simulink环境下对光伏电源利用直流 异步电机并网系统进行仿真,仿真结果验证了该方案的正确性和可行性.%According to the shortcoming of photovoltaic grid connected inverter with high cost, high failure rate, large harmonic content and complex control, a utility method of photovoltaic grid connected with DC-asynchronous motor was proposed. It consisted of a DC and asynchronous motor coaxial structure, and realized the conversion between DC and AC power. Asynchronous motor completed the starting process driven by DC motor whose power was supplied by photovoltaic and the connection switch would be closed when the motor speed was close to synchronous speed. When connected to grid, the active power output of asynchronous motor could be controled through the adjust of DC motor voltage,which could guarantee the stability of DC bus voltage. Based on MATLAB/Simulink simulation environment, the model of grid connected photovoltaic system with DC-asynchronous motor was build. The simulation results verified the correctness and feasibility of the method.