Carrier Phase Shift Method of SPWM for Concurrent Wired and Wireless Power Transfer Systems

This article presents an approach for concurrent power transfer to wired and wireless systems using just a single inverter. The approach utilizes a novel carrier phase-shift (CPS) method that independently controls the inverter output voltages at the fundamental and switching frequencies. This proposed method can be a cost-effective solution to wireless power transfer (WPT) systems used in contactless slip rings (CSRs), which transfer power to auxiliary loads such as sensors, radars, and IoT devices. There are two separate converters in conventional CSR systems: One is for the motor drive, and the other is for the WPT system. It is proposed that the switching harmonics of the motor drive can also be utilized to excite the WPT system while the low-frequency component can still be used to drive the motor. In order to control these independently, the CPS method is introduced. The proposed method is investigated analytically for sinusoidal-pulse width modulation. Then, an experimental setup consisting of a 3-phase 3-wire gallium nitride-based inverter and a 3-phase motor is built. Experimental results show that the WPT and motor systems are operated concurrently, and their powers are controlled independently by the proposed method.