Dishwasher Pump Control With Brushless PM Motors and Shared Electronics

The patent changes the fundamental operating parameter of the motor from dry-running to wet-running mode. By submerging the motor in the liquid being pumped, the cooling and lubrication conditions change, allowing simpler sealing arrangements while maintaining high conveying capacity through optimized pump housing and impeller design.

The patent introduces an intermediary fluid medium (the liquid being pumped) that serves dual purposes: it cools and lubricates the motor bearings, replacing complex sealing systems, while also being the working fluid for the pump function.

The patent employs dynamic control of the three-phase power supply to the synchronous motor. By selectively activating different phases and using electronic commutation, the rotation direction of the impeller can be dynamically changed, allowing the pump to adapt to different operational requirements such as normal pumping or blockage removal modes.

The pump system achieves multi-functionality by using the same synchronous motor for both standard pumping operations and blockage removal. The control system enables the impeller to rotate in different directions, making the single pump capable of performing multiple functions that would traditionally require separate mechanisms.

The patent uses dynamic control of the synchronous motor to switch between different outlet configurations. The pump housing includes both a central outlet and a tangential outlet, and the control system directs flow through the appropriate outlet based on operational mode, optimizing both blockage removal and conveying capacity as needed.

The pump system employs periodic action by alternating between different rotation directions and outlet configurations. During normal operation, the pump uses one configuration for high conveying capacity, and when blockage is detected, it periodically reverses direction to clear the blockage, then returns to the optimal conveying configuration.