Abstract: According to an embodiment, a mixed signal controller includes a fine controller, a coarse controller and a digital controller. The fine controller is operable to output an analog modulation signal responsive to an analog control signal and a voltage signal input to the fine controller. The coarse controller is operable to output a digital pulse width modulation (PWM) signal responsive to the analog modulation signal and an analog PWM reference signal input to the coarse controller. The digital controller is operable to program the analog control signal and the analog PWM reference signal responsive to the digital PWM signal so that the fine and coarse controllers together regulate the voltage signal at a predetermined voltage level.

Abstract: According to an embodiment, a mixed signal controller includes a fine controller, a coarse controller and a digital controller. The fine controller is operable to output an analog modulation signal responsive to an analog control signal and a voltage signal input to the fine controller. The coarse controller is operable to output a digital pulse width modulation (PWM) signal responsive to the analog modulation signal and an analog PWM reference signal input to the coarse controller. The digital controller is operable to program the analog control signal and the analog PWM reference signal responsive to the digital PWM signal so that the fine and coarse controllers together regulate the voltage signal at a predetermined voltage level.

Abstract: A controller for variable speed three-phase AC squirrel-cage induction motors in accordance with a volts-per-hertz control method is disclosed. Direct current ("DC") link current is employed to compensate for rotor slip. In particular, rotor slip is estimated and added to a speed reference command to compensate for changing loads. A direction input and speed reference command provide complete control over the induction motor.