摘要
为解决电网电压畸变影响光伏逆变器电流控制性能的问题,提出一种基于比例积分谐振(PIR)调节器的电流控制方法.首先确定了光伏逆变器含有电流内环、直流电压外环的控制结构,PIR调节器用于对电流内环中电网电压畸变扰动的抑制与基波电流的跟踪.由于光伏逆变器的LCL滤波器与PIR调节器阶数较高,在设计控制参数时面临诸多问题,接着提出一种基于离散系统根轨迹法的PIR调节器参数设计方法,避免了连续域设计的调节器参数直接应用于数字控制器,从而引发调节器性能偏差甚至失稳.分析结果显示,在电网频率以及LCL滤波器参数变化时,设计参数依然可使系统具有较好的适应性.最后在Simulink上搭建仿真模型,验证了基于PIR调节的电流控制方法的可行性以及所设计调节器参数的正确性.
To solve the problem of grid voltage distortion affecting the current control performance of photovoltaic inverter,a current control strategy based on proportional-integral-resonant(PIR)regulator is proposed.Firstly,the control structure of photovoltaic inverter with inner current-loop and outer DC voltage-loop is determined.PIR regulator is used to suppress the grid voltage distortion or disturbance in inner current-loop and track the fundamental current.Due to the high orders of the LCL filter and PIR regulator in the photovoltaic inverter,there are many problems in the design of control parameters.Then,aparametric design method of PIR regulator based on the discrete-time root locus is proposed,which avoids the performance deviation or unstability of the regulator when the regulator parameters based on continuous domain are directly applied to the digital controller.Analysis results show that the design parameters can still make the system have a good adaptability during the changes of the grid frequency and LCL filter parameters.Finally,a simulation model based on Simulink verifies the feasibility of the current control strategy based on PIR regulator and the correctness of designed controller parameters.
引文
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