Current limit determination of brushless DC motors for binary speed control of known load torque speed characteristics

Binary speed control combined with the current limit (hysteresis) control is a low cost method of brushless DC motor speed control. Although it is desirable that the entire speed torque characteristic of the mechanical load is determined experimentally. However, in the absence of the actual load, motor and the sufficient hardware; the parameters of a standard motor are used in simulation. Also a flexible torque speed characteristic is framed to represent a variety of loads through software. An algorithm is developed using limited number of calculated average currents to yield smooth changes in speed.