电力电子负载是一种灵活、节能地考核电源质量的装置，其并网变换器将测试能量高质量馈回电网。依据电路模型首先建立控制系统，结合系统工况对直流环节电压谐波分布情况进行分析，为抑制其对馈网电能质量的影响，通过对比陷波、低通、均值3种滤波器效果，并最终采用稳态特性最优的改进均值滤波器。为抑制大容量电容和均值滤波器等大惯性环节对系统动态性能的影响，基于有功功率平衡思想建立了小信号模型和相应的前馈控制方案，有效抑制了输入电压、电流和电网电压扰动对系统的影响。改进重复控制器作为电流环控制器提高电流跟踪精度和馈网功率因数。实验和仿真结果验证了所做分析的正确性和控制方法的有效性。

The power electronic load is a device that can measure the quality of the power source conveniently and economically with the high-quality feedback of the testing energy from its grid connection converter (GCC). This paper gives the electrical model and the control scheme based on the GCC circuit, and analyzes the harmonic components based on the structure and the function of the power electronic load (PEL). According to the comparison of the effects of the notch filter, low-pass filter and mean filter, the mean filter has been chosen to filter the harmonics components mixed with the DC voltage for its perfect steady-state characteristics. Large inertia links such as DC capacitor with large capacity and mean filter deteriorate the dynamic characteristics, and the small signal model based on active power balance is constructed. The feedforward control strategy is applied to ensure the whole system has the perfect dynamic response, when the input voltage, input current and grid voltage flicker fluctuate. The improved repetitive controller is employed to ensure the inner current loop has zero-error track characters and maintains the GCC with a close unity power factor. The experimental and simulation results show that the analysis is right and the new control scheme is effective.

国家自然科学基金项目(50777026)；湖北省自然科学基金项目(2007ABA051)。