Digital power supply
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Solution Overview
Problem
Existing power supplies for high-powered loads, such as electric grills, fail to provide precise control over multiple heating elements while introducing significant harmonics and flicker into the power system, leading to inefficient energy delivery and reduced heating element lifespan.
Innovation Solution
A digital power supply system that uses a microprocessor to calculate and deliver phase-controlled AC wave patterns to multiple heating elements, allowing independent control and reducing harmonic currents and flicker by using triacs and zero crossing detection to manage power delivery based on user input and temperature feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If variable resistors are used to control power delivery to electric loads, then power control is achieved, but harmonics are introduced onto the electrical system and power efficiency decreases
Solution Approach 1:
The patent replaces mechanical variable resistors with a solid-state power controller that uses triacs and phase-angle control to regulate power delivery. This electronic substitution eliminates the need for physical resistance adjustment while maintaining precise power control capability without introducing harmonics or reducing efficiency.
Solution Approach 2:
The invention changes the control parameter from resistance adjustment to phase-angle control of AC waveforms. By varying the firing angle of triacs, the system controls the portion of the AC cycle delivered to the load, achieving power regulation without the harmful effects of resistive control including harmonics and energy waste.
2Ease of operation
If bi-metal thermometer is used to control power delivery, then power control is achieved, but response time increases and temperature control precision decreases
Solution Approach 1:
The patent replaces the mechanical bi-metal thermometer with an electronic temperature sensing system coupled with a microprocessor. This substitution enables rapid detection of temperature changes and immediate adjustment of power delivery, eliminating the thermal lag inherent in bi-metal mechanisms and achieving precise temperature control.
Solution Approach 2:
The invention implements a closed-loop feedback system where temperature sensors continuously monitor the load temperature, the microprocessor compares actual temperature against target values, and automatically adjusts power delivery accordingly. This feedback mechanism provides rapid response and precise temperature maintenance without the delays characteristic of bi-metal thermostats.
3Device complexity
If half-wave control techniques are used to deliver power, then power delivery is simplified, but power delivery is restricted to stages rather than continuous range
Solution Approach 1:
The patent transitions from static half-wave control to dynamic phase-angle control where the triac firing angle can be continuously adjusted within each AC cycle. This dynamic approach allows smooth, continuous variation of power delivery from 0% to 100% rather than discrete stepped levels, providing fine-grained control while maintaining relatively simple circuitry.
4Adaptability or versatility
If multiple electric loads are controlled independently, then load control flexibility is improved, but harmonic currents and flicker introduction increases
Solution Approach 1:
The patent segments the control of multiple loads by providing individual triacs and phase-angle control for each load independently. This allows each load to be controlled separately according to its specific requirements while the overall system manages harmonic and flicker introduction through coordinated control strategies.
Solution Approach 2:
The invention uses phase-angle control parameters for each load, allowing independent adjustment of power delivery to multiple loads. By controlling the firing angle of each triac independently, the system achieves load flexibility while managing total harmonic distortion and flicker through distributed control rather than centralized switching.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise power control for multiple heating elements, reduces harmonic currents and flicker, and extends the lifespan of heating elements by providing continuous variable power delivery within the 0-100% range, compliant with harmonic and flicker regulations.
Implementation Method 1
delivering a phase-controlled AC wave pattern represented by the first phase angle array to the first heating element and delivering a phase-controlled AC wave pattern represented by the second phase angle array to the second heating element
Implementation Method 2
causing the microprocessor to receive a zero crossing signal from a zero crossing detection unit
Implementation Method 3
a first and second heating element inside the housing, the first and second heating elements being connected to the voltage line and the neutral line
Data Source
AI summary
Provided is an apparatus and method for a digital power supply that can provide independent power control, and control variable power, for two or more electrical loads. Disclosed embodiments may reduce the magnitude of harmonic currents and/or flicker introduced into a power system. Embodiments include a microprocessor that delivers power to electric loads using phase-controlled AC current. The microprocessor may calculate a power array corresponding to a requested power for each electric load. Logic is provided for populating the power array in a pattern that reduces the magnitude of harmonic currents and flicker.