Variable speed reference control of a high‐speed BLDC motor for a blender machine

Abstract

This study presents the design of a 2‐pole high‐speed BLDC motor for kitchen blenders and its control method with the aim to reduce the speed ripple that decreases the grinding performance in the high‐speed region. In blender machines, the high pulsating load caused by the blending materials such as ice cubes acting on the grinding blade, create significant speed ripple in the constant power region. Because current and torque are limited to protect the drive, the actual motor torque cannot overcome the pulsated load if the speed reference is maintained. Therefore, the speed fluctuates, and the grinding performance is lowered. In the proposed variable speed reference control scheme, the speed command is continuously modified to overcome the maximum pulsating torque requirement which results in lower speed ripple. To achieve this, if the load torque suddenly increases, the current value is then set based on the maximum load and speed reference value is temporarily lowered. If then the load torque becomes lower than the actual torque, the previously set speed reference value is reused. The design result and grinding performance of the proposed control method are verified by simulations and experiments. Hard white beans are used for actual performance testing.

Copper loss analysis and loss separation method in a dynamic process of ultra‐high speed motor with slotless stator

“…In ref. [12], one-dimensional magnetoquasi-static magnetic model of the stator slot region is used to establish the boundary transfer relationship between individual turns, and then the impedance matrix can be built and AC resistance can be calculated. In ref.…”