中文摘要：

提出了将直流模拟负载单元进行模块化设计,实现多模块并联且将电能回馈电网的节能方案。直流模拟负载模块采用并联输入并联输出的工作方式,数字控制和模拟控制相结合的混合控制方式,实现每个模块输入电流的独立高精度控制。为提高并网电能质量,采用基于离散傅里叶变换的闭环锁相控制方法,并网逆变控制引入重复控制实现周期性扰动的无静差调节。根据所提出的方案设计了样机,实验结果验证了该方案能实现模拟负载模块输入电流的精密控制,且有效抑制并网电流谐波,实现高功率因数,额定功率下并网电流总谐波失真为0.7%。

英文摘要：

The modularization of DC simulated load unit was presented. The energy-saving solution of multiple modules in parallel and electric energy feedback system was realized. Input-paralleled outputparalleled operation mode of DC simulated load module was adopted. Hybrid control strategy including digital control and analog control was applied to the control of simulated load module. The input current of each module was controlled independently. In order to improve the accuracy and reliability of the power grid phase lock,the control method of the closed-loop phase-locked control based on discrete Fourier transform was adopted. In order to realize the zero-error control of periodic disturbance,repetitive controller was put forward. A prototype was designed according to this scheme. Experimental results show that the scheme can realize the precision control of DC input current,the effective inhibition of current harmonic components,and high power factor. The THD of grid-connected current is 0. 7% under the rated power.