Control of Boost Converter Module for Open-End Winding Permanent Magnet Motor Based, Dual Inverter Drive

Abstract

This work explains how to control a boost converter module to vary the DC link voltage of a dual inverter motor drive. Doing so is shown to extend the speed range of open-end winding permanent magnet synchronous motors (OWPMSM) compared to using flux weakening control, enabling the use of more efficient and power dense high-speed motors. Such a speed range can be obtained by simply increasing the battery voltage, thus increasing the DC link voltage, and using flux weakening control. However, depending on the rebalancing technique used, cell imbalances in high-voltage batteries can decrease the efficiency and/or the battery lifetime, both of which are sensitive metrics in electric vehicles (EVs). Splitting the required battery voltage between two independent sources to drive the OWPMSM and using the boost converter modules to further increase the DC link voltage as needed extends the speed range while keeping the individual battery voltages low enough to prevent exacerbating cell-balancing issues. Furthermore, by adding the boost converter modules, the motor drive can satisfy the maximum torque per ampere (MTPA) condition at all speeds. Doing so decreases the maximum stator current above base speed compared to flux weakening control while maintaining the same torque-speed curve, thus lowering conduction losses. Simulation results from PLECS confirm the extended speed range and lower conduction losses of the topology compared to a conventional permanent magnet synchronous motor (PMSM) drive and a dual inverter drive without the boost converter modules. v