Dynamic modelling and control of a step up/down switching-mode rectifier

The authors present the dynamic modelling and control of a switching-mode rectifier (SMR) with step up/down voltage and power factor correction control. Depending on the output voltage level, this rectifier can be operated in buck or boost mode during each AC half cycle. It follows that this SMR possesses wide DC output voltage range, and it can be used as a battery charger with large charging flexibility for a serially connected battery bank. The power circuit of the proposed rectifier is first analysed and designed. Then its dynamic model is derived. Based on this, a current waveform controller is designed, such that sinusoidal line current with low harmonics and near unity power factor is obtained. In addition, a charging controller is also designed for yielding good dynamic charging characteristics. After confirming the validity of the designed rectifier by simulations, the circuit implementation is performed and some measured results are provided for further demonstrating its performance