Energy saving power control system and method

An AC power regulation system for controlling load power to a load, said power regulation system having an input for coupling to an AC power source and having an output for coupling to the load, said power regulation system comprising:

• a controllable switch coupled in series between the input and the output;
• circuitry for supplying capacitance coupled in parallel with the controllable switch;
• circuitry for generating power sense signals responsive to the load power;
• circuitry for turning-on the controllable switch to a conducting state;
• circuitry for turning-off the controllable switch to a non-conducting state;
• switch control circuitry for generating control signals to control said circuitry for turning-on and said circuitry for turning-off such that the controllable switch is turned on to a conducting state at a selected turn-on time, and is turned off to a non-conducting state at a selected turn-off time prior to a line current zero-crossing point, said turn-off time being selected by said switch control circuitry in response to said power sense signals;
• and
• circuitry for ensuring that said turn-off time initially occurs just in advance of a line current zero-crossing point.

A method of AC power regulation for controlling power to a load in an electrical system, said system having an input for coupling to an AC power source, an output for coupling to the load, and a controllable switch coupled in series between said input and said output, comprising the steps of:

• operating said controllable switch during a first mode of operation such that substantially full-power is supplied to said load;
• initiating a power reduction mode after said first mode, wherein power supplied to said load is gradually reduced during said power reduction mode from said substantially full power to a target value over a period of time;
• thereafter initiating a power-saving mode, wherein the power supplied to said load substantially corresponds to said target value;
• measuring a value representative of a phase angle of said load after said target value is achieved;
• storing said value representative of a phase angle of said load;
• and
• thereafter monitoring subsequent values representative of load phase angles and comparing them with said stored value representative of a phase angle to maintain a desired power savings with respect to said load.

A method of AC power regulation for controlling power to a load in an electrical system, said power regulation system having an input for coupling to an AC power source and an output for coupling to the load, and having a controllable switch coupled in series between said input and said output, comprising the steps of:

• operating said controllable switch during a first mode of operation such that substantially full-power is supplied to said load;
• initiating a power reduction mode after said first mode, wherein power supplied to said load is gradually reduced during said power reduction mode from said substantially full power to a target value over a period of time;
• gradually easing into said power reduction mode by initially turning off said controllable switch just in advance of a load current zero-crossing point;
• and
• causing the switch at all times to be in an off condition prior to the next-successive load current zero-crossing and causing the switch to be in an on condition following said next-successive load current-zero crossing.

A method of AC power regulation for controlling power to a load in an electrical system, said system having an input for coupling to the load and a controllable switch coupled in series between said input and said output, comprising the steps of:

• operating said controllable switch such that substantially full-power is supplied to said load;
• gradually reducing said power supplied to said load from said substantially full power to a target value over a period of time;
• measuring a value representative of a phase angle of said load after said target value is achieved;
• storing said value representative of a phase angle of said load;
• and
• thereafter monitoring subsequent values representative of load phase angles and comparing them with said stored value representative of a phase angle to maintain a desired power savings with respect to said load.

A method of AC power regulation for controlling power to a load in an electrical system, said power regulation system having an input for coupling to an AC power source and having an output for coupling to the load, and having a controllable switch coupled in series between said input and said output, comprising the steps of:

• operating said controllable switch such that substantially full-power is supplied to said load;
• reducing said power supplied to said load from said substantially full power to a target value over a period of time;
• gradually reducing said power supplied to said load by initially turning off said controllable switch just in advance of a load current zero-crossing point;
• and
• causing the switch at all times to be in an off condition prior to the next-successive load current zero-crossing point and causing the switch to be in an on condition following said next-successive load current zero-crossing point.