Motor Load Sensing by Time Measurement
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
High-performance stepper motor drives require a feedback signal from a step encoder to permit the stepper motor to operate at maximum performance. This mode of operation is known as closed-loop control, the load of the motor being defined by the time that passes between the electrical step (phase change) and the performed step (encoder signal). This time must be related to the actual motor speed to determine the momentary motor load which is defined as a lead or load angle. There are many types of closed-loop control, but all of them require a step encoder which is built into the motor or takes the form of a separate assembly. (Image Omitted) The gist of the present disclosure is to analyze the dynamic response of the motor phase current to the EMF (electromotive force) for determining the momentary motor load. Figs.