Abstract: According to the present invention, a fail-safe circuit for controlling an actuator is provided with an input voltage which is rectified and converted to a DC voltage. The DC voltage is boosted to a high level, and high voltage storage capacitors are charged at this high voltage level resulting in smaller, less expensive capacitors. The high voltage from the storage capacitors is then converted back to a smaller DC voltage to drive the motor of the actuator. Reduced size and increased energy storage is based on the relationship between capacitance and voltage in the equation: E=½ CV2.

Abstract: A controller for heating, ventilating and air-conditioning distribution systems, which includes feedforward and feedback control strategies. The controller has a feedforward control strategy that generates a control signal based on control set points and identified characteristics of the system, and which adaptively adjusts such set points based on changes that are measured with respect to the identified characteristics. The controller is particularly adapted for controlling the temperature during a heating or cooling operation in a controlled space.