Wireless Power Transmission for Powering a Sensor Placed at an Electrical Traction Machine with External Rotor

To improve the product characteristics of a traction machine, sensors, providing internal measurements, are an important tool during development. Sensors in the rotor of the electric traction machine, are monitoring the behavior of the traction machine during operation and can as well be used for process control while manufacturing. A major challenge is the electrical powering of the sensors on rotating parts of the machine and the transmission of the measured data, therefor methods for contactless power and data transmission are necessary. In this paper, a contactless power transmission track, supplying the rotating sensor, is investigated. The energy is transmitted orthogonally to the axis of rotation. The primary coil is located tangentially to the rotor and is fixed to the machine housing. The secondary coil is placed on the cylindrical outer side of the external rotor. That means that during rotation the coupling between the coils is partially lost. It is investigated whether such a system can transmit sufficient energy, so that the supply of a sensor is guaranteed. As an example, a temperature sensor is implemented in the rotor to monitor the temperature of the magnets. The measurement data is transmitted via Bluetooth Low Energy. The improvement in product properties that is being examined in this process will contribute to the use of TFMs in the context of e-mobility and the digitization of future vehicles.