Programmable electronic real-time load controller providing demand limit control

Claim 1

An electronic controller for controlling the energization states of a plurality of electrical loads, said controller comprising: a plurality of load control circuits, each said load control circuit being adapted to be interconnected with a load, and having a load-on state when its load is to be on, and a load-off state when its load is to be off; clock means for determining real-time; sensor means for measuring the actual rate of power consumption by the plurality of electrical loads; set point selector means for selecting a set point representing a desired rate of power consumption by the plurality of electrical loads; event memory means for storing a time schedule for real-time control of the plurality of electrical loads; program memory means storing a set of program instructions; processing means responsive to said set of program instructions for: determining a desired real-time control output status for each load by: obtaining real-time from said clock means; obtaining said time schedule from said event memory means; and through comparison of said real-time with said time schedule, establishing an on state or an off state for each load, said on state representing a desired load-on state for the associated load control circuit and said off state representing a desired load-off state for the associated load control circuit; determining a desired demand limit control output status for each load by: obtaining said actual power rate from said sensor means; obtaining said set point from said set point selector means; determining a shed condition when said actual power rate equals or exceeds said set point, and determining a restore condition when said actual power rate is less than said set point; establishing a demand group of the plurality of electrical loads; transferring a load into said demand group upon occurrence of an on state for the load and transferring a load out of said demand group upon occurrence of an off state for the load; establishing a shed group and a restored group within said demand group, the loads within said shed group having a shed state representing a desired load-off state for the associated load control circuit and the loads within said restored group having a restored state representing a desired load-on state for the associated load control circuit; upon determination of said shed condition, transferring at least one load from said restored group to said shed group; and, upon determination of said restore condition, transferring at least one load from said shed group to said restored group; and, controlling the actual energization state of each load by, for each load in said demand group, placing said load control circuit for the load into said load-on state upon occurrence of said restored state for the load and into said load-off state upon occurrence of said shed state for the load, and, for each remaining load, placing said load control circuit for the load into said load-on state upon occurrence of said on state for the load and into said load-off state upon occurrence of said off state for the load.

Claim 21

An apparatus that permits an electronic controller, adapted to provide real-time control of the energization states of a plurality of electrical loads, to also provide demand limit control of the loads, the controller including a clock means determining real-time, an event memory storing a time schedule for real-time control, a program memory storing a set of program instructions for real-time control, and a processing means for excuting the set of program instructions to implement real-time control by comparing real-time from the clock means with the time schedule in the event memory, and accordingly determining an on state or an off state for each load, and by energizing those loads in an on state and by de-energizing those loads in an off state, said apparatus comprising: a second program memory storing a set of program instructions for demand limit control; first means for providing an input analog signal representing the actual rate of power consumption by the plurality of electrical loads; second means for providing a set point analog signal representing a desired rate of power consumption; digital-to-analog signal conversion means for converting a digital signal from said processing means into a corresponding analog signal; a first comparator for comparing said input analog signal with said analog signal from said digital-to-analog signal conversion means to provide a first digital signal representative of the difference therebetween; a second comparator for comparing said set point analog signal with said analog signal from said digital-to-analog signal conversion means to provide a second digital signal representative of the difference therebetween; input/output port means for transferring said first and said second digital signals to said processing means, and for transferring a digital signal which selectively represents an approximation of said actual rate of power consumption and said desired rate of power consumption from said processing means to said digital-to-analog signal conversion means; said processing means being operative to execute said set of program instructions stored in said second program memory to implement demand limit control by: obtaining actual rate and set point data by causing said digital signal transferred to said digital-to-analog signal conversion means through said input/output port means to selectively approximate said actual rate of power consumption and said desired rate of power consumption and by selectively monitoring, through said input/output port means, said first and said second digital signals from said first and second comparators; comparing said actual rate data with set point data; and, for those loads in an on state under real-time control, varying the number of loads actually energized and de-energized so as to maintain said actual rate substantially equal to said set point.

Claim 22

An apparatus that permits an electronic controller, adapted to provide real-time control of the energization states of a plurality of electrical loads, to also provide demand limit control of the loads, the controller including a clock means determining real-time, an event memory storing a time schedule for real-time control, a program memory storing a set of program instructions for real-time control, and a processing means for excuting the set of program instructions to implement real-time control by comparing real-time from the clock means with the time schedule in the event memory, and accordingly determining an on state or an off state for each load, and by energizing those loads in an on state and by de-energizing those loads in an off state, said apparatus comprising: a second program memory storing a set of program instructions for demand limit control; first means for providing an input analog signal representing the actual rate of power consumption by the plurality of electrical loads; second means for providing a set point analog signal representing a desired rate of power consumption; digital-to-analog signal conversion means for converting a digital signal from said processing means into a corresponding analog signal; a first comparator for comparing said input analog signal with said analog signal from said digital-to-analog signal conversion means to provide a first digital signal representative of the difference therebetween; a second comparator for comparing said set point analog signal with said analog signal from said digital-to-analog signal conversion means to provide a second digital signal representative of the difference therebetween; input/output port means for transferring said first and said second digital signals to said processing means, and for transferring a digital signal which selectively represents an approximation of said actual rate of power consumption and said desired rate of power consumption from said processing means to said digital-to-analog signal conversion means; said processing means being operative to execute said set of program instructions stored in said second program memory to implement demand limit control by: obtaining actual rate and set point data by causing said digital signal transferred to said digital-to-analog signal conversion means through said input/output port means to selectively approximate said actual rate of power consumption and said desired rate of power consumption and by selectively monitoring, through said input/output port means, said first and said second digital signals from said first and second comparators; comparing said actual rate data with set point data; and, for those loads in an on state under real-time control, varying the number of loads actually energized and de-energized so as to maintain said actual rate substantially equal to said set point.