Soft-switching high quality rectifier employing a novel control scheme

Among the High Quality Rectifier (HQR) topologies proposed in the literature, the boost one has demonstrated to be as simple, powerful and cost-effective to become the most widely used in practical applications. In conventional designs, a boost HQR working in continuous conduction mode (CCM) needs to be input-current controlled besides being output-voltage regulated. This paper addresses the aim of an improvement of the boost HQR in terms of higher power density and simpler control stage, by a novel approach employing a quasi-resonant switching technique. In particular, Zero-Voltage Switching (ZVS) and Zero-Current Switching (ZCS) techniques have been investigated as a mean to obtain a resistor emulator behaviour of the boost converter in CCM by using a new sort of automatic current shaping capability, which means that no current control loop is required. The ZCS technique reveals to offer a practical way to reach the goal. Correspondingly a new control strategy has emerged which employs the voltage control loop only, maintaining all the input-side features of CCM and allowing higher conversion frequencies. The characteristics of the novel HQR scheme are discussed in detail and analysis, simulation as well as experimental results are provided.