Sensor units for motor control of hybrid and electric vehicles

Brushless permanent magnet synchronous motors require a sensor that provides the position of the rotor with a high degree of accuracy to enable accurate motor torque control and to achieve maximum efficiency and dynamics. These permanent magnet motors use either direct drive control or sine wave control. SKF sensor units can contribute to optimized motor efficiency for both systems.

Units for direct drive control

For direct drive control, SKF supplies commutation units delivering three signals, each with a 120° phase shift. The number of pulses per revolution matches the number of rotor pole pairs. These units comply with the speed and temperature requirements typical for power steering applications, high-speed spindles and small brushless electric drives.

Units for sine wave control

For sine wave control, SKF supplies sensor bearing units providing the shaft angle position in real time within the entire motor speed range. These integrated units provide a signal comparable to the one provided by a resolver and can therefore be used by the motor controller’s software. The shaft angle position is communicated via a sinus/cosinus signal.

SKF can adapt the electronics to comply with the interface of the application. The units can provide either an analogue or a digital encoder-like output signal. The units are more compact and cost-effective than inductive resolvers. They are easy to mount and do not require special shaft or housing accuracy.

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