An Isolated AC/DC Converter Using a Matrix Converter: A Feedback Control Method Considering the Non-linearity of a Diode Rectifier

This paper introduces a matrix converter control method for an isolated AC/DC converter with a resonant circuit that considers non-linearity of the diode rectifier. The method achieves a high output frequency equals to the switching frequency, a constant DC output voltage, sinusoidal input currents, and unity input power factor. Furthermore, soft switching with maximum output power factor is realized by a frequency control. In this type of circuit, the harmonics of the matrix converter output current are caused by the non-linearity of the diode rectifier. A conventional method neglects these harmonics, which cause input current distortion and DC voltage ripple. In a proposed method, the control variables are numerically calculated considering the non-linearity of the diode rectifier and implemented in a lookup table. In addition, a DC voltage feedback is applied to compensate for the effects of parameter error, e.g., voltage drop of the power semiconductor device and deadtime of the MC. The proposed method is evaluated experimentally.