The research and implementation of mid-frequency power supply with high power factor and multi-closed loop feedback

The harmonic current of nonlinear rectifier can generate the grid pollution and reduce the power factor on the structure of AC / DC / AC of the 400Hz mid-frequency power supply. To solve this problem the paper proposes to adopt active power factor correction (APFC) circuit on the input side to reduce harmonic and improve the power factor. When the inverter power output is with nonlinear loads and dead zone etc., it can cause the distortion of the output voltage waveform and the poor real-time of RMS feedback. For this the article adopts a multi-closed loop feedback control strategy, i.e. the capacitor current is the inner loop, voltage is mid-loop and root meam square (RMS) or the amplitude is the outer loop. And it also uses the instantaneous reactive power theory abc/dq0 on the current and voltage detection to improve the real time. Finally the system is verified on the experimental platform controlled by DSP2812, the software flow and test results are also given.