Abstract: A flow control apparatus for a pressure system includes a chamber, a pump for providing a flow from the chamber and a valve positioned between the chamber and the pump for providing regulation of the flow. The valve is continuously operable between a fully open and a fully closed position. A motor continuously operates the valve between the open and closed positions. The motor includes a position encoder including an encoder output. A sensor continuously monitors the flow and includes a sensor output. A system interface receives the encoder output and the sensor output. The system interface processes the position encoder output to determine position and velocity of the motor and using at least the sensor output, position and velocity produces control signals for the motor. A servo driver receives the control signals from the system interface and continuously controls the motor in a closed-loop manner to regulate the flow.