A Z-source sparse matrix converter with a fuzzy logic controller based compensation method under abnormal input voltage conditions

A novel Z-source sparse matrix converter (ZSMC) is developed based on the structure of a sparse matrix converter (SMC) to reduce the number of unipolar power semiconductor switches. It also employs a Z-source network to overcome the inherent limitation of the low voltage transfer ratio of the conventional matrix converter. The ZSMC still, however, connects a three-phase voltage source to a three-phase load without energy storage elements at the dc-link. Although there are several passive components at the dc-link, these are not for suppressing voltage and current ripples, but mainly for utilizing buck-boost features of the Z-source network. Therefore, the output of the ZSMC is directly affected by the disturbance or unbalance in the input voltage. In this paper, the operational principle of the ZSMC is described and the behavior of the ZSMC under abnormal input voltage conditions is investigated. A compensation method based on a fuzzy logic controller is presented to improve the output performance of the ZSMC under abnormal input voltage conditions. The simulation results are shown to demonstrate the validity of the compensation method.