DC motor drive system and method

摘要

A DC motor go for driving a linear pump is controlled by a system which improves speed/torque relationship. The motor current is sensed 40 and compared 62 with a modified command signal so as to produce constant torque under varying operating conditions of speed and back emf. Circuits 45 46 simulate winding phase currents using capacitor discharge in dependence on an average speed signal 64 which also modifies 63 a set-point signal. A circuit 65 compensates for rate of change of winding current.