基于统一坐标变换的三电平有源电力滤波器研究

Research on three-level active power filter based on unified coordinate transformation

为实现有源电力滤波器电流的无静差控制,以三电平并联型有源电力滤波器(SAPF)为研究对象,将统一坐标变换(UFP-CT)应用到三电平SAPF电流控制中。详细推导出了三电平SAPF在三相静止abc、两相静止、统一坐标坐标系下的数学模型;采用常规的电压前馈电流解耦控制策略,同时对由坐标变换带来的自干扰和耦合干扰进行前馈以克服其对输出的影响,控制器采用PI控制器,即可实现谐波电流的无静差跟踪。采用Simulink进行了仿真,并和dq坐标系下控制方法进行了对比。仿真结果表明:基于统一坐标变换设计的电流控制器可以实现对谐波电流指令的无静差跟踪,且具有更优的动态特性。

To realize the zero steady-state error current control of active power filter,taking three-level shunt active power filter（ SAPF） as the object of study,the unified fixed point coordinate transformation（ UFP-CT） was applied to three-level SAPF current control in this paper. The concept of a unified fixed point coordinate transformation was introduced,and the mathematical model of three-level SAPF in the three-phase stationary abc,two-phase stationary α-βand unified fixed δ-ζ point coordinate system was deduced in detail. It used the conventional voltage feed-forward current decoupling control strategy,the feed-forward was also introduced to overcome the impact of self-interference and coupled interference brought by UFP-CT on output,and PI controller was utilized to achieve the zero steady-state error current control. Simulink is used to carry on the simulation,and the control method has carried on the contrast with control strategy under the dq coordinate system. Simulation results show that the proposed current control method can achieve harmonic current command without static error tracking based on unified coordinate transformation,and has better dynamic characteristics.