Keywords: power quality, boost rectifier, total harmonic distortion, THD, switched mode power supply, SMPS, power factor, boost dc–dc full bridge converter, telecommunications power supply, quality improvement, zig–zag transformers
Analysis, design and control of a two stage improved power quality telecommunication power supply
This paper deals with the power quality improvement at the utility interface of a telecommunication switched mode power supply (SMPS) of 12 kW rating. The first stage of this SMPS consists of a 6–pulse diode bridge converter that performs ac–dc conversion yielding an unregulated dc voltage. In the second stage, two boost rectifiers are connected together which feed to a boost dc–dc full bridge converter connected to the output load. By means of a closed loop control, appropriate value of third harmonic component of the current is injected using a zig–zag transformer to reduce the current harmonics distortion at the utility interface. A detailed design procedure is presented to select various components of the SMPS system.