Digital Power Supply Triac Control Reduces Harmonics
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Solution Overview
Problem
Existing power supplies for high-powered loads, such as electric grills, introduce significant harmonic and flicker interference into the power grid, lacking precise control over multiple loads and efficiency, with prior solutions like variable resistors and bi-metal thermometers offering limited precision and efficiency.
Innovation Solution
A digital power supply system using triacs and a microprocessor to deliver discrete power levels to multiple heating elements, allowing independent control and reducing harmonic and flicker interference, with wireless control capabilities for remote monitoring and operation.
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 variable resistors (mechanical/electrical component) with a microprocessor-based digital control system that uses triacs to switch power delivery. This substitution eliminates the continuous resistance adjustment that generates harmonics, replacing it with precise electronic switching control that achieves power regulation without harmful electromagnetic emissions.
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 in relation to the AC waveform, the system delivers precise power levels without the harmonic distortion inherent in resistor-based control, fundamentally changing how power delivery is regulated.
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 burning
Solution Approach 1:
The patent replaces resistive power control (which dissipates excess power as heat) with triac-based phase-angle control. This substitution changes the energy loss mechanism from continuous thermal dissipation in resistors to minimal switching losses in solid-state triacs, dramatically improving power efficiency while maintaining precise control capability.
3Ease of operation
If bi-metal thermometers are used to control power delivery, then temperature control is achieved, but control precision decreases and response time increases
Solution Approach 1:
The patent replaces bi-metal thermometers (mechanical sensing system) with digital temperature sensors and microprocessor control. This substitution eliminates the mechanical lag and limited resolution of bi-metal strips, providing rapid digital temperature measurement and precise control decisions with millisecond response times and high measurement resolution.
4Ease of operation
If bi-metal thermometers are used to control power delivery, then temperature control is achieved, but heating element lifespan decreases due to long on/off duty cycles
Solution Approach 1:
The patent implements high-frequency periodic switching control using triacs, cycling between on and off states many times per second based on temperature feedback. This high-frequency periodic action prevents the long continuous on/off cycles that cause thermal stress and degradation in heating elements, significantly extending their operational lifespan while maintaining precise temperature control.
5Ease of operation
If half-wave control techniques are used to deliver power, then power delivery control is achieved, but power delivery is limited to stages rather than continuous range
Solution Approach 1:
The patent implements dynamic phase-angle control where the triac firing angle can be continuously adjusted anywhere within the AC waveform cycle. This dynamic control mechanism allows smooth, continuous power delivery from 0% to 100% by varying the proportion of each AC cycle that is conducted, eliminating the stepped power delivery limitation of half-wave control techniques.
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 digital power supply provides precise control over multiple loads, reduces harmonic and flicker interference, extends the lifespan of heating elements, and complies with regulatory standards, enabling efficient and precise temperature management in electric grills.
Implementation Method 1
a heating element connected through a triac to a voltage line
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
Provided is an apparatus and method for a digital power supply that can provide independent power control for two or more electrical loads. Some disclosed embodiments provide continuous, variable power and other disclosed embodiments provide discrete power levels. 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. In some embodiments, 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. Portions of the disclosure include a band controller for delivering power to achieve and maintain a desired target temperature, and a wireless controller for controlling temperature from a remote device.