Research on matrix converter control strategy under abnormal input voltages

Due to lack of dc-link energy storage elements in the matrix converter, any disturbance in the input voltages will be immediately reflected to the output voltages. In order to guarantee safe and stable operation of matrix converters under abnormal input voltage conditions, the paper proposes an improved method to real-time calculate voltage modulation ratio using the space vector magnitude of output and input voltages. The input current performance of matrix converters is analyzed using this strategy and a method to eliminate the harmonic components of the input current under unbalanced input voltage conditions is presented. Some numerical simulations are presented to confirm the analytical results. Tests are carried out on a 5kW matrix converter prototype. Experimental results verify the proposed strategy in the paper works very well without an additional control circuit. Just need to adjust the calculation of space vector modulation ratio that the matrix converter can output three-phase sinusoidal symmetrical voltage under normal and abnormal input voltage conditions.