Pacific Technology, Inc.

Warren L Leyde

Delbert E Marker

Don R Hall

In an electrical load control system, an analog signal representing the actual rate of power being consumed by a plurality of loads has a nominal level when the actual rate is at a desired rate, or set point. As the level of the analog signal deviates from its nominal level, the electrical load control system functions to add or shed one or more of the loads to maintain the actual rate at the set point. During times of low power consumption, the electrical load control system may not act to optimize energy usage if the set point is not lowered. A set point control circuit is provided which senses the on/off status of one of the loads, or control load, and which provides a set point modification signal whose level represents a desired reduction in the set point and which varies in a predetermined range between minimum and maximum levels representing, respectively, no reduction in the set point and a maximum reduction in the set point. Whenever the control load is on, the set point modification signal slowly increases toward its maximum level, and whenever the control load is off, the set point modification signal rapidly decreases toward its minimum level. Summation of the set point modification signal with the analog signal in the electrical load control system effects the desired reduction in set point.

Floating set point control circuit and method for use with electrical

To maintain power consumption within predetermined limits, the ON/OFF states of a plurality of electrical loads are controlled by a digital load control circuit that forms part of a closed-loop control system. The power consumed by the ON loads is monitored and compared with a reference and in response to such comparison command signals are produced that instruct the digital circuit to add or shed loads as required, to increase or decrease, respectively, the power consumption. Inputs to the load-control circuit are in the form of one or more add or shed command pulses wherein the former instructs the circuit to add a load, and the latter instructs the circuit to shed a load. To execute these commands, the load-control circuit includes a reversible, recycling address generator that successively addresses a bank of addressable latches, one for controlling the ON/OFF state of each load. As the latches are successively addressed, logic circuitry operates to detect a concurrence of an add command and an OFF load state at the addressed latch, or a concurrence of a shed command and an ON load state at the addressed latch. Detection of the former set of conditions causes the then addressed latch to be switched from its load OFF state to its ON state and detection of the latter set of conditions causes the then addressed latch to be switched from its load ON state to its OFF state. Various embodiments of the foregoing are disclosed including circuitry for selectively dividing the plurality of loads into two different groups, one of which is a fixed priority group wherein the loads thereof are added and shed in a fixed order, and the other of which is a rotate group wherein the order that the loads are added and shed is rotated so that all of the loads of such group equally share the available ON time; and circuitry for selecting a limit to the total number of rotate loads that can be ON at any given time and a limit to the number of such loads that can be OFF at any given time.

Digital load control circuit and method for power monitoring and

In a closed loop control system for monitoring and regulating the rate of electrical power delivered to a plurality of electrical loads, an improved circuit is disclosed that is responsive to an analog input signal representing a measured power rate and has a digital pulse output for conditioning a digital switching circuit to add one or more loads when the measured power rate falls below a predetermined rate and to shed one or more loads when the measured power rate exceeds such predetermined rate. The analog input signal is compared with a reference signal to produce an analog error signal that is first compensated for certain types of power rate deviations and is then fed to an analog to digital conversion circuit which includes a threshold detection circuit and a pulse generator circuit and produces one or more output pulses in response to a predetermined threshold magnitude of the compensated error signal. The polarity of the error signal is detected to steer the output pulses to one or the other of a pair of inputs of a load control switching circuit, one input thereof being effective to add a load and the other input being effective to shed a load in response to each received pulse.

Power monitoring and regulating circuit and method having an analog

In an electrical load control system, method and apparatus are provided for selectively, individually connecting and disconnecting a plurality of loads to and from a power source. The loads are selectively connected (added), disconnected (shed), and reconnected (restored or added), in a predetermined sequence, wherein the ranking of the loads in such sequence is selectively rotated in a manner which results in a sharing of on and off time and an equalizing of wear among all of the loads. As an example of this operation, a load control system is disclosed in which the consumption of electrical power is varied by periodically shedding and adding individual loads in order to maintain the level of power usage below predetermined limits and yet make full use of the available power within such limits. For this purpose, a load regulating circuit monitors the power consumption and issues either an add command signal causing one or more loads to be connected, or issues shed command signal causing one or more of the loads to be disconnected, that is, shed. To uniformly distribute the off time associated with shed loads among all the loads, a load switching circuit means and a load rotation circuit means are provided for rotating the order in which the loads are shed, and thereafter restored or added. The rotation takes two forms. First, the order or rank in which the plurality of loads are shed, is shifted or rotated after each occurrence of a condition in which all of the loads have been turned on. Secondly, when less than all of the loads are on, the on-off ranking or status of the loads, resulting from the preceding add or shed command, is periodically shifted or rotated among all of the loads, in order to share the available electrical power on a timed rotation basis. Thus, the disruption of load service due to the curtailed power, is time shared among all of the loads on an equal, non-priority basis.

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Seattle, WA, United States of America

Warren L Leyde