Design and control of wireless permanent-magnet brushless DC motors

Abstract

Recently, wireless power transfer for electric motor technology has been studied, where the primary side can drive the motor without physical contact, so the load motor can be employed in isolated environments. This article proposes a wireless permanent-magnet brushless DC (PM-BLDC) motor. Prominently, the secondary side does not involve any motor control chip, as the motor is fully controlled by the WPT controller at the primary side. The key is to employ three widely orthogonal channels with six LC tuning circuits at the secondary side, which can replace the motor controller to regulate the secondary inverter. Thus, the robustness of the motor side is ruggedized and highly improved by eliminating the most fragile component, i.e., the controlling microchip. Circuit simulations and an experimental prototype verify and demonstrate that the proposed three-phase PM-BLDC motor can be driven wirelessly with a single primary controller from 400 to 4000 rpm with 20 mm wireless power transfer distance, and the transmission efficiency can be as high as 80.2%.