Improving the DC-Link Utilization of Nine-Switch Boost Inverter Suitable for Six-Phase Induction Motor
Pinjala Mohana Kishore, Ravikumar Bhimasingu
Abstract
Nowadays, multiphase induction drives are used in electric vehicle applications to improve reliability and efficiency. These induction motors are controlled by using a multiphase voltage-source inverter (VSI). As the number of phases increases, the number of switching devices used in multiphase VSI also increases, which results in a reduction of the system efficiency and an increase in the cost. Among these multiphase drives, the six-phase drive is used more frequently in electric vehicular industries. A conventional six-phase VSI requires 12 switches to drive the six-phase machine. Also, conventional six-phase VSI requires more dc-link voltage than the boost six-phase VSI to drive the six-phase machine. In order to overcome the problems associated with the conventional six-phase VSI-controlled six-phase induction drives, this article proposes a nine-switch boost inverter (NSBI) for six-phase induction drive applications. The proposed NSBI has a single-input dc voltage source, and it provides six-phase ac output voltages. These six-phase output voltages are regulated by using modified nonsinusoidal pulsewidth modulation (MNSPWM) technique. The proposed NSBI with a six-phase induction motor is simulated using MATLAB/Simulink and validated using a field-programmable gate array (FPGA)-controlled hardware prototype. The verification of the proposed system during load-torque variations and winding-failure conditions is carried out.