A DC power supply based on matrix converter with reduced number of switches

High Power telecommunication power supply systems consist of a three-phase switch mode rectifier followed by a DC/DC converter to supply loads at 48 VDC. These rectifiers draw significant harmonic currents from the utility, resulting in poor input power factor with high total harmonic distortion (THD). In this paper, a DC power supply based on matrix converter with reduced number of switches is proposed for telecommunication applications. In the proposed approach, three switches convert the low frequency (50 Hz, three-phase) input to a DC link. A single-phase bridge inverter converts the DC-link to a high frequency (25 KHz, one-phase) AC output. The output of the matrix converter is then processed via a high frequency isolation transformer and rectified to 48 volt DC. In the proposed topology only a simple voltage control loop ensures that the output voltage is regulated against load changes as well as input supply variations. The input currents are of a high quality and devoid of low frequency harmonics under varying load conditions, inherently. Therefore, the current control loop is not used to correct the input currents. So, its control circuit is not complicated. Simulation results verify the feasibility of the proposed converter.