A 12 kW switching mode power supply with free input-voltage

Phase-controlled AC to DC power conversion has the disadvantages of low power factor and harmonic pollution on the utility side, particularly in the case where DC voltage regulation is required. This paper presents a 12 kW switching mode power supply for a telecom power system. The scheme employs a buck-type power converter in the front-end resulting in high input power factor and less harmonics to the utility. A two-loop controller with a feedback and a feedforward loop is used to minimize the effects of the rectified ripple voltages and to improve the system dynamics. Since it also has a very wide input-voltage range, it can be directly applied for both the input systems of AC 220 V and 380 V