Mechatronic design of a PM brushless motor-driven gear pump with sensorless control

The paper presents a review of all the design choices made during the realization of a novel hydraulic motor-pump-unit (MPU) for automotive applications, driven by a permanent magnet (PM) brushless motor with sensorless control. The MPU designed in this project is characterized by low voltage supply and high hydraulic output power, so that the choice of power electronic components have been particularly challenging, mainly because of conflicting requirements in terms of current rating and total cost. The experimental results obtained with a first MPU prototype demonstrates that the weak point of the complete mechatronic design is related to the volumetric efficiency of the gear pump, while the power converter and brushless motor assembly is characterized by a reasonable efficiency.