Johnson Service Company

Johnson Controls Gmbh

David P DeBoer

August A Divjak

David W Jiral

An apparatus for controlling an electrical appliance coupled with an output terminus and configured to operate in response to an alternating input signal, such as input AC power. The apparatus comprises a reference signal generator for receiving the input signal and generating a reference signal (either V.sub.RAMP or V.sub.CONTROL) in response to the input signal, and a control circuit for controlling connection of the input signal to the output terminus in response to the reference signal and to a user-defined set-point signal. The control circuit is coupled with the reference signal generator and with a set-point terminal. The set-point terminal receives the set-point signal and the control circuit controls connection of the input signal with the output terminus in response to a predetermined relationship between the reference signal and the set-point signal; the apparatus is capable of generating a modified periodically interrupted AC power output based on an AC power input. In a preferred embodiment, the modified AC power output is asymmetrically periodic.

Appliance AC power control apparatus

A proportional plus integral controller operates an actuator in an HVAC system. The controller includes a setpoint circuit for providing a setpoint signal representative of a desired room temperature, a sensor circuit for providing a sensor signal representative of the actual room temperature, an error generator for generating an error signal proportional to the difference between the setpoint signal and the sensor signal, and an integrator for generating a control signal related to the time integral of the error signal. The setpoint and sensor signals are derived from a common voltage reference, so that accuracy of the controller is substantially independent of fluctuations of that reference. The integrator includes a capacitance multiplier that provides highly accurate integration of the error signal and a switch for selecting either proportional plus integral or proportional only control. The controller includes an integration disable circuit that removes the integral term from the control signal when the proportional component becomes large enough to fully drive the actuator. The controller also includes a mode selector to configure the controller to operate in either a heating or cooling mode.

Anti-windup proportional plus integral controller

A control device for energizing and de-energizing temperature changing devices having a primary control unit and a secondary control unit is provided. The primary control unit includes means for sensing an external temperature and generating a signal (Ps) having a value proportional to the external temperature, means for generating a set point signal (Psp), representing one end of a predetermined primary temperature range, and means for generating a differential signal (Pd), representing the difference between signal Psp and the other end of the predetermined primary temperature range are included. Additionally, the primary unit includes a primary switch for connecting power to at least one temperature changing device which is opened and closed in response to combinations of signals Ps, Psp and Pd. The secondary unit includes means for generating an offset signal (So) and means for generating a secondary set point signal (Ssp) having a value proportional to a combination of signal Psp and signal So, and representing one end of a predetermined secondary temperature range. The secondary unit further includes means for generating a secondary differential signal (Sd) representing the difference between signal Ssp and the other end of the predetermined secondary temperature range.

Growing community of inventors

Cedarburg, WI, United States of America

David P DeBoer