Research On High Power Factor Rectifier Applied To Mid-frequency Supply

Based on the one-cycle-controlled (OCC) single phase VIENNA rectifier, single phase PWM rectifier applied to mid-frequency supply is studied deeply in this article.At first, how the OCC single phase VIENNA rectifier realizes high power-factor commutation is analyzed. Under simple analog controller, the output split capacitance voltage can be maintained in balance by adjusting the total output voltage. By establishing the system model, a equivalent current loop is gained, as a result that, the voltage loop gets simplified. When the load changes suddenly, owing to the narrow bandwidth of the voltage loop, the output voltage may change in large-scale. So, load-current feedforward control is designed to alleviate the role of the voltage modulator. And, as a result, the dynamic characteristic of the system gets improved remarkably.Analyses to the input current of the conventional one-cycle control are presented, and the conclusion that, input current contains low-frequency odd harmonics under the conventional single-edge modulation, is received. Then, bi-edge modulation on this basis is proposed. Under the new modulation, the low-frequency odd harmonics of input current is eliminated, and the quality of the input current gets improved. In addition, when two converters operate in parallel, influence on the input current by interleaved and complementary control is revealed.Due to the particularity of higher input frequency in OCC PWM rectifier, the necessity of using LCL filter is analyzed. And, the proof, why the system is stable when converter-side inductance current is sampled, is presented.In order to validate the correctness of the analyses, simulations or experiments have been done. At last, a prototype integrating all the above presented analyses is built. The experimental results indicate that, the rectifier adopted one-cycle control possesses high power-factor, excellent input current quality and fast dynamic response, and satisfies the design criteria under the mid-frequency supply system condition.