Closed Loop Current Control Stepper Motor

Closed loop step motor the encoder is used as a feedback source in a position loop which adjusts the torque requirements in real time.

Closed loop current control stepper motor.

The most advanced closed loop stepper control method is to operate the motor as a two phase brushless bldc motor. The encoder is also being used in a current loop to determine the proper electrical angle to apply to the motor. Closed loop stepper systems supply the motor with just enough current to control the load and this results in much less audible noise than open loop setups. To produce the test results shown in the plot of acoustic noise accompanying this article the acoustic noise of each system is measured in a soundproof chamber.

If an error occurs between the command and motor position due to a load or the like the system immediately switches to closed loop control like a servo motor. Under normal circumstances the operation of the motor is monitored and control is applied using open loop like a standard stepper motor. Closed loop stepper motor performance αstep these stepper motors use our alphastep closed loop technology to maintain positioning operation even during abrupt load fluctuations and accelerations without hunting or gain tuning. The rotor position detection sensor monitors the rotation speed and amount.

Note that many stepper motors have two phases offset by 90 whereas brushless dc motors have three phases offset by 120 this method is referred to as servo stepper or closed loop stepper control.