单相并网逆变电流分数阶PI控制策略研究

Single-phase Grid-connected Inverter Current Fractional PI Control Strategy

摘要:

并网发电系统中，逆变器输出的并网电流易受到电网电压周期性扰动等非线性因素干扰，导致并网电流波形畸变。建立单相光伏并网逆变控制系统模型，设计一种逆变电流分数阶PI(PIλ或FO-PI)控制器，根据控制系统的频域特性，确立控制器的比例、积分系数及积分阶次与系统性能指标的关系；在整数阶PI控制器和分数阶PI控制器的分别作用下，对系统的动态和稳态性能、抗干扰性及并网逆变特性进行仿真对比，并应用快速傅里叶变换（FFT）对系统各自的逆变并网电流质量进行了分析。仿真结果表明，分数阶控制系统在满足各项稳态性能指标的同时，降低了并网电流谐波总畸变率（THD），并提升了系统的动态性能和抗干扰能力。

Abstract:

In the grid power system, grid-connected current are easily perturbed by electric gird voltage and other nonlinear factors so that the current waveform deforms. By setting up a model for single grid-connected photovoltaic controller, designing a factional inverter current controller and according to the frequency domain, the relationship between the controller’s portion, integral coefficient, derivative degree and system performance are decided. Under the consideration of the influence by both the integral fractional PI controller, the performance of system under dynamic and static state, anti-interference and grid-connected character are compared in simulate way. And the quality of current waveform for each system is calculated respectively by applying FFT. The result from simulate analysis, fractional control system lower the THD and improve the performance of anti-interference under both dynamic and static state, as well as satisfying other requirements stability index.