一种光储直流微网经直流-异步电机并网控制方法

A Control Strategy Based on DC-asynchronous Motor of DC Microgrid with Photovoltaic and Storage System

针对并网逆变器存在的谐波含量大、故障率高、控制方法复杂等问题,提出了一种光储直流微网经直流-异步电机并网控制方法。该光储直流微网中,光伏电源工作在MPPT模式,蓄电池储能系统工作在恒压模式,以维持直流母线电压恒定。直流电机拖动三相异步电机旋转,三相异步电机定子绕组与交流电网相连,当三相异步电机转速接近同步速时,并网开关合闸,实现光储直流微网并网运行以及直流电能和交流电能之间的相互转换。光储系统并网后,通过调节直流电机端电压对光储直流微网输出有功功率进行控制,使光储系统可以达到"削峰填谷"的目的。在MATLAB/Simulink中对本文所提出的光储微网及其并网环节进行建模,仿真结果验证了该控制方法的可行性和有效性。

In view of the problems of large harmonic content,high failure rate,and complex control method in grid-connected inverters,this paper proposed a grid-connected DC microgrid control method.In the photovoltaic storage DC microgrid,the photovoltaic power supply operated in MPPT mode and the battery energy storage system operated in constant voltage mode to maintain the constant DC bus voltage.The DC motor drove the three-phase asynchronous motor to rotate.The stator windings of the three-phase asynchronous motor connected to the AC grid.When the speed of the three-phase asynchronous motor approached the synchronous speed,the grid-connected switch was closed to realize the grid-connected operation of the DC storage system and the conversion between DC and AC power.After the photovoltaic storage system connected to the grid,the output active power of the photovoltaic storage DC microgrid was controlled by adjusting the terminal voltage of the DC motor,which can achieve the purpose of“cutting peak and filling valley”.The proposed photovoltaic storage microgrid and its connection to grid were modeled in MATLAB/Simulink.The simulation results verified the feasibility and effectiveness of the control method.