Current mode control of a brushless motor is widely used in many industries and products. Some conventional motor control system creates an error signal by comparing a current reference signal and a measured current signal, and uses the error signal to adjust the voltage applied to a brushless motor using a voltage supply inverter. Some of the motor control systems utilize reference current signals for both the q (quadrature) and d (direct) axes of the motor, in order to utilize a minimum amount of motor current for a given motor torque command, motor velocity, and supply voltage. The minimum current reference command is used as the input to a feedback current control loop, where the measured current(s) are subtracted from the reference current(s) to generate error signals used within a PI (proportional-integral), PID (proportional-integral-derivative), or other control loop structure. However, the minimum current reference command may cause performance degradation when the control systems operate near the supply voltage limit.
USPTO Backgrounds
USPTO Backgrounds