Microprocessor controlled motor controller with current limiting protection

Abstract

A solid motor controller for controlling the current in an electrical motor. The motor controller includes a processing unit, and a solid state switch operatively connected to the electrical motor. The motor controller senses the current through the motor, compares the current with a reference current level, and limits the current in the motor by rapidly switching the switch between an ON and an OFF state when the current exceeds the reference current level. The controller de-energizes the motor by placing the switch in the OFF state when the current exceeds the reference current for a predetermined period of time. The controller also includes a second solid state switch which is controlled to rapidly stop the rotation of the motor. The motor controller also activates a high current warning when the current exceeds a high current limit. Further, the motor controller senses the battery voltage, provides a low voltage warning indication when the battery voltage falls below a predetermined value, and shuts down the motor when the battery voltage falls below a second predetermined value. Finally, the controller measures the temperature near a selected component and shuts down the motor when the temperature exceeds a predetermined value.