A Multilevel PFC Rectifier with Sensor-Less Voltage Balancing Capability

Most modern world appliances have an intermediate AC to DC rectifier, whether used for DC (LEDs, chargers) or applications with internal motors (refrigerator, washing machine). The conventional rectifiers distort the power factor and introduce harmonics in the grid. Multilevel rectifiers (MLR) with power factor correction (PFC) and high load handling capability have gained much research focus, and numerous topologies have been reported. However, most of them either fail to maintain the unity power factor (UPF) across the entire power range or to maintain UPF employ external circuitry and control. Further, capacitor voltage balancing is another major issue in MLR. In this regard, this brief proposes a sensor less self-balanced MLR topology that maintains UPF in all operating conditions. Experimental results have been presented for validation of the claims mentioned above of the implemented topology. A quantitative comparison with the recent literature has also been included.