Capacitance Reduction Method for Voltage Doubler Partial Switching PFC Converters Using Motor Neutral Point

This paper proposes a method that uses motor leakage inductance to reduce the capacitance in voltage doubler partial switching power factor correction (PFC) converters by utilizing the leakage inductance of a motor. The proposed circuit connects the neutral point of the capacitor leg in the voltage doubler partial switching converter to the neutral point of the motor. This method reduces the capacitance of the capacitor leg by controlling the neutral-point voltage through the zero sequence of a three-phase inverter and the leakage inductance of the motor. Furthermore, the proposed approach incorporates balancing control for the neutral-point voltage of the capacitor leg. An IS-P control strategy is implemented within the voltage control system to enhance the performance of the balancing control because the unbalanced component is primarily influenced by the double-frequency component of the power supply. The validity of the proposed method was confirmed through a prototype. The results showed that capacitance was reduced by 99.6%. In addition, the DC offset in the input current is reduced by 76% by applying voltage balance control.