Resonant Power Supply Feedback Control for Zero-Voltage Switching
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Solution Overview
Problem
Existing power supplies face inefficiencies due to excessive resonant voltages caused by stray capacitance and inductance, leading to increased switching loss and reduced conversion efficiency in resonant converters.
Innovation Solution
A power supply system with a transformer, storage capacitors, resonant circuit, and control circuits that stabilize and compensate resonant voltages by adjusting duty cycles and providing zero-voltage switching through feedback mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a resonant converter is used to achieve soft-switching, then switching loss is reduced and conversion efficiency is improved, but excessively large resonant voltages may occur due to stray capacitance and inductance, causing the converter to fail in providing zero-voltage switching
Solution Approach 1:
The patent implements a feedback mechanism where the control circuit monitors the resonant voltage and adjusts the duty cycle of the power switch accordingly. When the resonant voltage exceeds a predetermined threshold, the control circuit automatically reduces the duty cycle to compensate and stabilize the resonant voltage, ensuring zero-voltage switching is maintained despite variations in stray capacitance and inductance.
Solution Approach 2:
The patent dynamically changes the duty cycle parameter of the power switch based on the resonant voltage level. By adjusting this key parameter in real-time, the system adapts to varying circuit conditions and maintains optimal resonant voltage levels, preventing excessive voltages that would compromise zero-voltage switching capability.
2Stability of the object's composition
If the duty cycle is increased to compensate for voltage drops, then output voltage stability is improved, but resonant voltages become excessively large, increasing switching loss
Solution Approach 1:
The control circuit employs feedback to monitor both output voltage and resonant voltage levels. Instead of simply increasing duty cycle to compensate for voltage drops, the system uses feedback to make precise, balanced adjustments that maintain output stability while preventing resonant voltage from becoming excessively large, thus avoiding increased switching loss.
Solution Approach 2:
The patent introduces dynamic control where the duty cycle is continuously adjusted based on real-time monitoring of resonant voltage conditions. This dynamic approach allows the system to respond adaptively to changing loads and voltage conditions, maintaining output stability without the need for excessive duty cycle increases that would harm resonant voltage levels.
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 achieves low switching loss and high conversion efficiency by stabilizing resonant voltages, ensuring zero-voltage switching and reducing inefficiencies.
Implementation Method 1
The transformer is configured to transfer energy of the input voltage from a primary side to a secondary side for supplying the output voltage
Implementation Method 2
the inductors and capacitors in the resonant converter generate LLC resonance which converts the voltage established across the power switch into sinusoid voltage or current, thereby achieving soft-switching
Data Source
AI summary
A power supply includes a transformer, a power switch, a resonant circuit, a voltage stabilization and feedback compensation circuit, and two control circuits. The power switch operates according to a first control signal so that the transformer can convert an input voltage into an output voltage. The voltage stabilization and feedback compensation circuit provides a feedback voltage associated with the input voltage and lower the feedback voltage when receiving a fourth signal having an enable level. The first control circuit adjusts the duty cycle of the first control signal and provides the fourth signal having the enable level when receiving a detecting voltage having a specific level. The second control circuit provides second and third signals for driving the resonant circuit, detects the resonant voltages of the resonant circuit, and provides the detecting voltage having the specific level when determining that the resonant circuit fails to provide zero-voltage switching.