Microprocessor-Based Digital Power Supply for Multi-Load Phase Control
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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, limiting their effectiveness and lifespan.
Innovation Solution
A digital power supply system using a microprocessor to independently control two or more heating elements by delivering phase-controlled AC wave patterns, reducing harmonic currents and flicker through the use of triacs and zero crossing detection, allowing for continuous variable power delivery from 0-100%.
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 microprocessor-based digital control system that uses triacs to switch power delivery. This electronic substitution eliminates the harmonics generated by variable resistors while maintaining precise power control capability through digital phase-angle control of AC waveforms.
Solution Approach 2:
The system changes the control parameter from continuous resistance adjustment to discrete phase-angle control of triacs. By controlling the firing angle of triacs, the system delivers precise power levels without the harmonic distortion inherent in variable resistor circuits, achieving both power control and electrical cleanliness.
2Ease of operation
If variable resistors are used to control power delivery to electric loads, then power control is achieved, but power efficiency decreases due to power burn
Solution Approach 1:
The patent replaces resistive power control with triac-based phase-angle control. Instead of dissipating excess power as heat through variable resistors, the system uses solid-state switching to deliver precise power levels, dramatically improving energy efficiency by eliminating wasteful power dissipation.
3Ease of operation
If bi-metal thermometer is used to control power delivery, then power control is achieved, but control precision decreases and response time increases
Solution Approach 1:
The patent replaces the mechanical bi-metal thermometer with a digital microprocessor control system. This substitution enables precise digital measurement and control of power delivery, eliminating the imprecision and thermal lag inherent in bi-metal mechanisms while providing accurate, responsive power control.
4Ease of operation
If bi-metal thermometer is used to control power delivery, then power control is achieved, but heating element lifespan decreases due to long on/off duty cycles
Solution Approach 1:
The patent implements continuous periodic phase-angle control of AC waveforms instead of intermittent on/off cycling. By delivering power in controlled phases throughout each AC cycle, the system maintains steady heating element operation without the thermal stress of repeated on/off cycles, thereby extending element lifespan.
5Device complexity
If half-wave control techniques are used to deliver power, then power delivery is simplified, but continuous variable power delivery from 0-100% is not achieved
Solution Approach 1:
The patent implements dynamic phase-angle control that can adjust the firing angle of triacs across the entire AC waveform range. This dynamic control enables continuous variable power delivery from 0% to 100% by precisely controlling when during each AC cycle the triac fires, providing full adaptability while maintaining manageable system complexity.
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
The system provides precise power control, reduces harmonic currents and flicker, extends the lifespan of heating elements, and complies with regulatory standards, enabling simultaneous cooking of different foods at varying temperatures.
Implementation Method 1
delivering a phase-controlled AC wave pattern to the heating element
Implementation Method 2
the microprocessor to receive a zero crossing signal from a zero crossing detection unit
Data Source
Figure 1A
Figure 1B
Figure 2
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.