Unity Power Factor Operation of Indirect Matrix Converter Tied to Unbalanced Grid

This paper presents a new control method for indirect matrix converter operating under unbalanced grid voltages. The proposed method aims to achieve balanced output voltages as well as a near unity input power factor operation. First, an opportune reference current accurately generated, and a proportional integral resonant controller are designed in a dq reference frame that is synchronized with the positive sequence of the grid voltages so as to achieve a perfect tracking of input reactive power reference. Then, a real-time estimator of the virtual dc-link voltage is developed with the aim to provide balanced output voltages; therefore, an almost constant active power free of low frequency ripple is supplied from the grid. Experimental results are presented to verify the feasibility and effectiveness of the proposed control method.