Ultra sparse matrix rectifier for battery charging application

Abstract

Charging batteries with constant-current/constant-voltage (CCCV) scheme prolongs the battery life and improve the charging efficiency. In battery charging applications, using ultra-sparse matrix rectifier (USMR) has many advantages over the bridge rectifier circuits as it has minimum number of switches, it possesses sinusoidal input currents with controllable displacement angle by proper switching strategy. So, a unity power factor can be achieved. This paper presents the use of USMR in battery charging applications using of space vector modulation (SVM) to provide sinusoidal input currents for USMR. Also controlling of output current or voltage facilitates charging control during charging scheme to preserve the battery life. The three modes of CCCV charging scheme are trickle mode, constant current mode, and constant voltage mode. The output dc voltage of the rectifier is controlled by controlling the modulation index m for the rectifier, hence the output dc current is consequently controlled. The input side LC low-pass power filter is designed to filter out the harmonics in the input currents due to switching frequency. This type of charger is candidated for high power high charging voltage systems to improve the charging efficiency. The simulation results show that the proposed control scheme achieves sinusoidal input current with a unity power factor. Also, the total harmonic distortion in the input line current decreases as the charging current increases.