US 4,282,422 A · Power control for appliance using multiple high inrush current elements

Abstract

A power control system is disclosed which controls the power output of one or more resistive heating elements in response to operator selected power level settings. Control of power to the elements is accomplished by generating a multi-bit binary word representing a selected power level, each bit being operative to control the application of power to the element during a different control interval. A control word is generated for each element and is updated once during every associated control period, a period comprising a number of intervals equal to the number of heating elements. The heating elements are of a type which draw a relatively high current during a transient heat-up period. The application of power to other elements is inhibited when one of the elements is having power applied thereto during its transient period. Power control for each element is staggered by testing a bit of different positional value in each word during any given interval.

Claims25

Dependent claims

A power control arrangement adapted for connection to a pulsating power supply for controlling the power output of a plurality of heater elements comprising:

an operator control including an OFF setting and means for selecting desired power levels for each element,
means for generating a pulse train, the time between pulses defining a control interval,
logic means responsive to said operator control for generating a binary control word representing a selected power level for each heating element, each word including a plurality of bits, and
means for controlling power to each of said elements during any given interval as a function of the state of a selected one of said bits in the control word associated with said element,
detecting means associated with each element for detecting a transition from said OFF setting to a desired power level for its associated element,
means associated with each element responsive to said detecting means for defining a transition period of predetermined duration for its associated element, initiated by said detection of said transition, and
means for inhibiting power to all other elements during those control intervals in which power is applied to a heating element operating in its transient period.

4 more elements

A power control system for controlling the power output of a plurality of heating elements comprising:

means for electronically defining repetitive control intervals,
means for generating control words, each word associated with a different element, each word representing a desired power output from its associated element, each word including a plurality of bits, the bits of a selected word operative to control power to the element associated therewith over a plurality of intervals, and
means for controlling the application of power to each element over a plurality of control intervals as a function of the state of different bits in the word associated with said element, wherein each bit of a word is characterized by a first or second state, and by a position value within its associated word, and wherein said means for controlling the application of power includes means for controlling power to different elements during any given interval in accordance with the state of bits having different position value in their associated words.

A power control system adapted for connection to a power supply for controlling the power output of a plurality of heater elements in response to operator selected power level settings comprising:

a plurality of control word generating means responsive to said operator selected power level settings, each control word generating means associated with a different one of said heater elements, each of said control word generating means operable, when enabled, to generate a binary control word representing the power level selected for its associated heating elements.
timing means for defining repetitive control intervals of fixed duration,
means for successively enabling a different one of said control word generating means during each control interval, and
means for controlling power to each of said elements in any given interval as a function of the bit pattern of its associated control word, whereby control of power to each of said elements is displaced in time with every other element by at least one control interval.

1 more element

Dependencies are inferred from the claim text.

Power control for appliance using multiple high inrush current elements

Life of this patent

Power control for appliance using multiple high inrush current elements

Life of this patent

Abstract

Claims25