Novel Switched Capacitor Boost Inverter Configuration for Three-Phase Induction Motor Driven Home Appliances

To operate a 3-φ induction motor from a voltage source of low magnitude, 3-φ inverters are traditionally cascaded with a boost-type dc-dc converter. However, the use of inductors in the boost stage results in larger volume and weight of the overall motor drive system besides increased losses. To address this issue, an inductor-less boost inverter configuration for 3-φ, low power home appliance motor drives is proposed in this article. The proposed converter is formed by integrating a switched capacitor voltage boosting circuit with a 3-φ inverter. As, the proposed configuration results in an unusual space vector (SV), two novel pulsewidth modulation strategies are proposed: virtual vector space vector modulation (VSVM) and common mode voltage reducing (CMVR) space vector modulation (SVM). The use of VSVM improves the current total harmonic distortion (THD) and reduces the torque ripple while the CMVR SVM results in a 66.6% reduction of CMV without using any external hardware other than the boosting network. As compared to the conventional solutions, the proposed configuration incurs lower losses, improved current THD, and reduced semiconductor requirement. Simulation and experimental results are presented to validate the various claims. A thorough switching and conduction loss analysis is also carried out using the PLECS software.