Energy management method and apparatus utilizing duty cycle reduction synchronized with the zero points of the applied voltage

• US 4,245,319 A
• Filed: 03/19/1979
• Issued: 01/13/1981
• Est. Priority Date: 03/19/1979
• Status: Expired due to Term

• Current Assignee: Cyborex Laboratories Incorporated
• Original Assignee: Cyborex Laboratories Incorporated
• Inventors: Hedges, Walter P.
• Primary Examiner(s): Atkinson, Charles E.
• Assistant Examiner(s): Chin, Gary
• Application Number:
  US06/021,347
• Time in Patent Office: 666 Days
• Field of Search: 307/31, 307/32, 307/35, 307/38, 307/40, 307/41, 307/129, 340/147 F, 364/492, 364/493, 363/164, 363/165
• US Class Current: 700/296
• CPC Class Codes: H02J 2310/52 The controlling of the operation of the load not being the total disconnection of the load, i.e. entering a degraded mode or in current limitation
• CPC Class Codes: H02J 2310/60 Limiting power consumption in the network or in one section of the network, e.g. load shedding or peak shaving
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

Energy management method and apparatus for use in conjunction with a demand-limited alternating current circuit having a plurality of separate loads, including resistive loads, and means for automatically shedding certain of the loads when the actual demand of the circuit exceeds the demand limit. The actual demands of the loads in operation are sensed and the demands of at least certain of the operative resistive loads are separately sensed. The duty cycle of the power applied to at least certain of the operative resistive loads is reduced by switching these loads "off" and "on" synchronously with the zero points of the applied voltage. An overall reduction in the actual demand of the circuit is thereby effected when the failure to make such reduction would otherwise cause certain of the operating loads to be completely shed.

Claims

1. A energy-management method for use in conjunction with a demand-limited alternating current circuit having

a plurality of separate loads, including resistive loads, and

means for automatically shedding certain of said loads when the actual demand of said circuit exceeds said demand limit,

said method including:

(a) establishing a demand limit for said circuit;

(b) sensing the actual demand of those loads in said circuit which are in operation, including separately sensing the demands imposed by at least certain of the operative resistive loads in said circuit; and

(c) reducing the duty cycle of the applied power furnished to at least certain ones of said operative resistive loads by switching said loads "off" and "on" synchronously with the zero points of the applied voltage, to effect an overall reduction in the actual demand of said circuit when the failure to make such reduction would otherwise cause certain of said operating loads to be completely shed.

2. Energy-management apparatus for use in a demand-limited alternating current circuit, which circuit includes a plurality of separate loads, including resistive loads, and means for automatically shedding certain of said loads when the actual demand of said circuit exceeds said demand limit, said apparatus including:

(a) means for establishing a demand limit for said circuit;

(b) means for sensing the actual demand of those loads in said circuit which are in operation, including separately sensing the demand imposed by at least certain of the operative resistive loads in said circuit; and

(c) means for reducing the duty cycle of the applied power furnished to at least certain ones of said operative resistive loads by switching said loads "off" and "on" synchronously with the zero points of the applied voltage, to effect an overall reduction in the actual demand of said circuit when the failure to make such reduction would otherwise cause certain of said operating loads to be completely shed.