Design of Wireless Individual-Drive System for Variable-Reluctance Stepping Motor

In this brief, a novel wireless individual-drive system for variable-reluctance (VR) stepping motor is proposed and implemented. The key is to use coil groups to drive each phase of the VR stepping motor individually through magnetic resonance coupling. Based on the proposed structure, the VR stepping motor can be driven wirelessly while the motor side is free of active components. Meanwhile, the constant current drive is achieved without a chopper. The proposed system enables the VR stepping motor to work with higher independence and robustness compared with the cable-powered motor. The system design is described at first. Then, the equivalent circuit model is derived and analysed. In addition, the operation principle is displayed. Finally, a system prototype is constructed in the laboratory to validate the effectiveness of the proposed system. The experimental results show that 87.5% efficiency from dc power source to motor winding is achieved with the transmission distance of 50 mm. Moreover, the motor speed can reach up to 150 r/min and the motor torque can be regulated with the duty-ratio modulation.