Power control device and related methods

Abstract

A power control device for use in an AC power grid for regulating an electrical power a load that is supplied by the AC power grid consumes. The power control device has a frequency sensing functional block for detecting a deviation of the grid frequency from a nominal grid frequency and a logic functional block for performing a load adjustment process during which the power the load consumption is reduced. The load adjustment process is based at least in part on the variation of the frequency of the AC power grid. The load adjustment process is design such that for a plurality of power control devices the individual response produce a grid-wide effect that compensates imbalance between power generation and load in fashion that may reduce unwanted distortion in the AC power grid, such as flicker.

1 . A method for reducing aggregate load creep-up in a power distribution network which supplies an aggregate load including a plurality of individual loads controlled by respective power control devices, the power control devices being responsive to a power generation deficit in the power distribution network to reduce an electrical consumption of the respective loads to a level selected according a magnitude of the imbalance, the method including an act performed by each of the plurality of the power control devices subsequent the reduction of electrical consumption to the selected level, the act including progressively reducing the electrical consumption below the selected level to reduce a likelihood of aggregate load creep-up. 
     
     
         2 . A method as defined in  claim 1 , wherein a reduction of the electrical consumption to the selected level is performed according to a first average reduction rate, the act of progressively reducing the electrical consumption being performed according to a second average reduction rate, the first rate being higher than the second rate. 
     
     
         3 . A method as defined in  claim 1 , wherein a reduction of the electrical consumption to the selected level is performed during a first time period, the act of progressively reducing the electrical consumption being performed during a second time period, the first time period being shorter than the second time period. 
     
     
         4 . A method as defined in  claim 1 , wherein the act of progressively reducing the electrical consumption below the selected level is autonomously performed by each of the plurality of the power control devices. 
     
     
         5 . A method as defined in  claim 1 , wherein the act of progressively reducing the electrical consumption below the selected level is initiated when the power generation deficit reaches a nadir. 
     
     
         6 . A method as defined in  claim 1 , wherein each of the power control devices is responsive to a frequency of the electrical energy in the power distribution network to determine the magnitude of the power generation deficit. 
     
     
         7 . A method as defined in  claim 1 , wherein the act of progressively reducing the electrical consumption being performed according to an average reduction rate, the average reduction rate being related to an inertia of the load controlled by the power control device. 
     
     
         8 . A method as defined in  claim 1 , wherein the act of progressively reducing the electrical consumption being performed according to an average reduction rate, the method including selecting the average reduction rate among a plurality of reduction rates and progressively reducing the electrical consumption according to the selected reduction rate. 
     
     
         9 . A method as defined in  claim 1 , wherein the act of progressively reducing the electrical consumption being performed according to an average reduction rate, the method including determining the average reduction rate according to characteristics of the respective load controlled by the power controlled device and progressively reducing the electrical consumption of the load according to the determined reduction rate. 
     
     
         10 . A power control device for reducing aggregate load creep-up in a power distribution network which supplies an aggregate load including a plurality of individual loads, the power control device configured for controlling an electrical consumption of a respective load among the plurality of individual loads, the power control device comprising:
 a. one or more processors;   b. a machine readable storage encoded with software for execution by the one or more processors, the software defining an electrical consumption control logic operative for:
 i. in response to a power generation deficit in the power distribution network to reduce an electrical consumption of the respective load to a level selected according a magnitude of the imbalance; 
 ii. subsequent the reduction of electrical consumption to the selected level, progressively reducing the electrical consumption below the selected level to reduce a likelihood of aggregate load creep-up when a plurality of the power control devices autonomously control the electrical consumption of the respective ones of the individual loads. 
   
     
     
         11 . A power control device as defined in  claim 10 , wherein a reduction of the electrical consumption to the selected level is performed according to a first average reduction rate, the control logic progressively reducing the electrical consumption below the selected level according to a second average reduction rate, the first rate being higher than the second rate. 
     
     
         12 . A power control device as defined in  claim 10 , wherein a reduction of the electrical consumption to the selected level is performed during a first time period, the control logic progressively reducing the electrical consumption below the selected level during to a second time period, the first time period being shorter than the second time period. 
     
     
         13 . A power control device as defined in  claim 10 , wherein the control logic is configured for progressively reducing the electrical consumption below the selected level autonomously of another power control device operating in the power distribution network. 
     
     
         14 . A power control device as defined  claim 10 , wherein the control logic is configured for progressively reducing the electrical consumption below the selected level when the power generation deficit reaches a nadir. 
     
     
         15 . A power generation device as defined in  claim 10 , wherein the control logic is responsive to a frequency of the electrical energy in the power distribution network to determine the magnitude of the power generation deficit. 
     
     
         16 . A power control device as defined in  claim 10 , wherein the progressive reduction of the electrical consumption being performed according to an average reduction rate, the average reduction rate being related to an inertia of the load controlled by the power control device. 
     
     
         17 . A power control device as defined in  claim 10 , wherein the control logic is configured of progressively reducing the electrical consumption according to an average reduction rate, the control logic configured for selecting the average reduction rate among a plurality of reduction rates and progressively reducing the electrical consumption according to the selected reduction rate. 
     
     
         18 . A power control device as defined in  claim 10 , wherein the control logic is configured for progressively reducing the electrical consumption according to an average reduction rate, the control logic being configured for determining the average reduction rate according to characteristics of the respective load controlled by the power controlled device and progressively reducing the electrical consumption of the load according to the determined reduction rate. 
     
     
         19 . A power control device as defined in  claim 10 , including power electronics responsive to the control logic to vary an RMS voltage to the respective load to adjust the electrical consumption of the load. 
     
     
         20 . A power control device for use in a power distribution network supplying electrical energy to a plurality of individual loads, the power control device for use in controlling an electrical consumption of an individual load among the plurality of individual loads, the power control device comprising:
 a. an input for receiving information identifying a presence of a power generation deficit in the power distribution network;   b. a control entity;   c. power electronics for regulating a supply of electrical energy from the power distribution network to the individual load, the supply of electrical energy having sinusoidal voltage cycles, each sinusoidal voltage cycle including a positive half-cycle and a negative half-cycle, the control entity, configured for:   i. in response to a power generation deficit in the power distribution network, selecting a reduced non-nil electrical consumption level for the individual load among a plurality of possible reduced non-nil electrical consumption levels;   ii. determining a combination of half-cycles to block from the electrical energy supplied to the individual load corresponding to the selected reduced non-nil electrical consumption level;   iii. control the power electronics according to the determining to achieve the selected reduced non-nil electrical consumption level.   
     
     
         21 .- 70 . (canceled)