What Is a Motor Controller?

The motor controller is an integrated circuit that controls the motor to work according to the set direction, speed, angle, and response time through active work.

Small motors with powers below 300 W are used in many applications, such as automobiles,

The motor controller can be operated manually, remotely or automatically. It can only include the functions of starting and stopping the motor, and it can also include other more complex functions.

Motor controllers can be classified according to the type of motor, such as drive

The most widely used small motors include DC motors, brushless DC motors, and stepper motors. The main difference between stepper motors, DC motors, and brushless DC motors is their driving method. ^[1]

Each motor will have a corresponding controller, and the characteristics and complexity of the controller will vary with the performance required by the motor.

The simplest controller is a switch that connects the motor and power, such as small appliances or power tools. The switch can be operated manually or the motor can be started or stopped automatically using a relay or contactor connected to some sensors. The switch can have different selection positions to allow the motor to be connected to the power source in different ways, which may include reducing the voltage when the motor starts, running in reverse, or choosing a different speed. Small controllers may omit protection devices such as overload and overcurrent. At this time, external overcurrent protection circuits are used to avoid excessive current. Some small motors have built-in overload protection. They automatically open the circuit to avoid overload when overloading. Larger motors have overload relays or temperature sensing relays in the controller, and fuses or circuit breakers to avoid overcurrent. Automatic motor controllers may also include limit switches or other equipment to protect the machine.

More complex motor controllers can precisely control the speed and torque of the motor, and may also be part of a closed-loop control system for mechanically controlled positions. For example, a CNC lathe needs to accurately control the position of the tool according to a preset curve, and it must be compensated according to the load and external forces to maintain the tool at a predetermined position. ^[1]