馈能型电子负载的并网控制

分析了单相馈能型电子负载的原理，主电路采用DC/DC/AC结构，DC/DC变换器采用平均电流模式下的双闭环控制，详细分析了逆变交流侧并网控制方法。基于内模控制原理，逆变器采用零误差电流跟踪并网控制方法，与普通PI控制方法相比，采用该方法后，工频条件下输出电流可以零误差地跟踪给定电流，基本不受电网电压的影响。仿真结果表明，该控制方法可以使逆变器输出电流的相位和频率无误差地跟踪电网电压的相位和频率，逆变电流为正弦，功率因数为1，可以连续调节模拟负载，并且有较好的瞬时响应。

Grid-Connected Control of Feedback Type Electronic Load

The authors present the principle of single-phase feedback type electronic load. DC/DC/AC converter is adopted as the main topology structure. The load includes two parts: DC/DC converter and DC/AC inverter. DC/DC converter takes advantage of a double closed-loop control method based on average current mode. The grid-connected control method for the AC side of inverter is analyzed in detail. Based on the principle of internal model control, the grid-connected control with zero-error current tracking is applied to the inverter. Comparing with traditional PI control, when the proposed control approach is adopted, the output current can trace the preset current with zero-error and is basically not influenced by voltage of power grid under the condition of power frequency. Simulation results show that the proposed control approach can make both phase and frequency of inverter’s output current trace both phase and frequency without error, the waveform of inverted current is sinusoidal and its power factor is equal to 1; the simulated load can be adjusted continuously and its instantaneous response performance is good.