Variable wattage control system

A control system that limits wattage provided by a heating-producing element to a value less than that produced at full line voltage, the system comprising:

• at least one heat-producing means;
• a power control means operatively associated with said at least one heat-producing means;
• and
• a power limiting function that limits the wattage provided by said at least one heat-producing means to a value less than that produced at a full line voltage through the use of a scaling function,
• wherein said power control means is phase angle fired and includes a circuit provision to enhance the accuracy of phase angle power control at low conducting angles, by allowing one or more “off” cycles to occur between phase-angled-fired “on” cycles, thereby allowing an increase in the conduction angle of said phase-angled-fired “on” cycles.

A variable wattage control system for providing varying wattage levels for a power-receiving device, the system comprising:

• at least one power-receiving device operatively associated with a temperature sensing means;
• the temperature sensing means communicating with a temperature controller for comparing a sensed temperature with a predetermined set point;
• a power controller operatively associated with said temperature controller for providing energization of said at least one power-receiving device at a selected maximum wattage level;
• the temperature controller being operative such that, if said sensed temperature, when compared to the set point, indicates that the system requires heat, the temperature controller directs the power controller to energize said at least one power-receiving device, which is limited to a specific maximum wattage level;
• a micro-controller which determines a power output scaling factor based on the percentage of a full line voltage being applied to said at least one power-receiving device and then scales said power output scaling factor accordingly;
• said power output scaling factor determining the maximum percentage power to be applied to said at least one power-receiving device;
• and
• such that a said at least one power-receiving device may be driven at different power levels for various applications.

A variable control system for providing varying wattage levels for a power-receiving device, the system comprising:

• at least one power-receiving device operatively associated with a sensing means for sensing an operating parameter of said power-receiving device;
• said sensing means communicating with a sensor-responsive controller for comparing said sensed operating parameter with a predetermined set point;
• a power control means of said sensor-responsive controller, for providing energization of said power-receiving device at a selected wattage level;
• the sensor-responsive controller being operative such that, if said sensed operating parameter, when compared to the said predetermined set point, indicates the need for more power from said power-receiving device, said sensor-responsive controller directing said power control means to energize said power-receiving device, which is limited to a specific maximum wattage level;
• a micro-controller which determines a power output scaling factor based on the percentage of a full line voltage being applied to said power-receiving device and then scales the power output provided to energize said power-receiving device accordingly;
• and
• said power output scaling factor determining a maximum percentage power to be applied to said power-receiving device;
• such that said power-receiving device may be driven at different power levels for various applications with a power rating specification as great or less than the power rating specification of the system.

A method of variable wattage control comprising the steps:

• a) providing an electrically powered heat-producing means, a power control means linked to a power source for supplying power to heat-producing means, a sensing means operatively associated with said heat-producing means for sensing temperature associated with the heat-producing means and communicating signals corresponding to the sensed temperature to a temperature controller for controlling the power control means to apply power to the heat-producing means according to the sensed temperature;
• b) determining a scaling factor output for applying power applied to the heat-producing means by the power control means in accordance with ratings specification of said heat-producing means;
• c) communicating the sensed temperature to the temperature controller;
• d) causing the temperature controller to have a re-scaled output to the power control means which limits and re-scales output power from the power control means;
• and
• e) applying power from the power control means to the heat-producing means at a power level determined by the temperature controller to maintain said sensed temperature relative to a temperature set point;
• whereby the power level supplied to the heat-producing means is scaled according to said scaling factor.

A method of variable wattage heater control comprising the steps of:

• a) providing an electrically powered heater, a power control means linked to power source for supplying power to the heater, a sensing means operatively associated with the heater for sensing temperature associated with the heater and communicating signals corresponding to the sensed temperature to a temperature controller for controlling the power control means to apply power to the heater according to the sensed temperature,
• b) employing a micro-controller to determine a power output scaling factor according to a scaling function, based on the percentage of a full line voltage being applied to the heater, by first calculating available power at full line voltage using the following equation:
• P
• line
• =
• (
• V
• line
• )
• 2
• R
• heater
• c) then scaling the power output applied to the heater by calculating said power output scaling factor, Kout, using the following equation:
• K
• out
• =
• P
• desired
• P
• line
• d) operating the temperature sensing means such that it communicates the sensed temperature reading to the micro-controller;
• e) operating the micro-controller such that it compares the sensed temperature to a predetermined temperature set point and determines a required percentage power output level, Pout, and then calculates a scaled percentage power output, Pout scaled, using the following equation:
• Pout scaled=Pout*Kout
• and
• f) operating the micro-controller such that said micro-controller instructs the temperature controller to communicate a signal to the power control means and establishing the desired power output to the heater element;
• whereby the power control means provides a power output to the heater which is properly scaled for the heater.

A method of using a variable wattage control system for providing varying wattage levels for a heating element, where the heating element may be required to be driven at power levels less than a power level capability of the system comprising the steps of:

• a) using a temperature sensing means for measurements of a temperature associated with the heating element during operation thereof;
• b) providing the temperature measurement to a temperature controller for comparing the temperature measurements with a predetermined set point;
• c) using a power control means of the temperature controller, for providing energization of the heating element at a selected wattage level;
• the temperature controller operating such that, if the sensed temperature, when compared to the predetermined set point, indicates the system requires more heat, the temperature controller directs said power control means to energize the heating element, which is limited to a specific maximum wattage level;
• and
• d) using a micro-controller to determine a power output scaling factor based on the percentage of a full line voltage being applied to the heating element;
• and
• e) scaling the power output provided to energize the heating element accordingly;
• and
• f) causing the power output scaling factor to determine the maximum percentage power to be applied to the heating element;
• such that the heating element is not driven at a power level greater than its power level rating.