Resonant Power Converter Control for Zero-Voltage Switching
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Solution Overview
Problem
Conventional resonance-type power transmission apparatuses experience a decrease in power conversion efficiency when output power deviates from its rating, due to non-uniform current phases.
Innovation Solution
Simultaneously adjusting the switching frequency and time ratio of the switching element to satisfy the condition of zero-voltage switching, thereby maintaining high efficiency across varying output power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output power is changed from near the rating in a conventional resonance-type power transmission apparatus, then the output power varies, but the power conversion efficiency decreases
Solution Approach 1:
The patent changes the switching frequency parameter dynamically according to the output power level. When output power changes from near the rating, the switching frequency is adjusted to maintain the resonant condition and zero-voltage switching, thereby preventing degradation of power conversion efficiency while allowing output power variation.
2Loss of energy
If the switching frequency is adjusted to maintain zero-voltage switching when output power changes, then power conversion efficiency is maintained, but the control complexity increases
Solution Approach 1:
The control device monitors the output power level and uses this feedback to adjust the switching frequency accordingly. This closed-loop control ensures that the switching frequency is continuously optimized to maintain zero-voltage switching conditions, thereby preserving high power conversion efficiency across varying output power levels without requiring complex additional circuitry.
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
Prevents a decrease in power conversion efficiency and maintains high efficiency even when output power changes, reducing switching loss and ensuring efficient operation over a wide power range.
Implementation Method 1
a resonance circuit including a resonance coil Lr and a resonance capacitor Cr connected in series
Implementation Method 2
a switching element S and a control device 9. The switching element S switches an input to the resonance circuit
Data Source
Figure 1
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AI summary
A method for controlling a power conversion device for converting power from a power supply by controlling an input to a resonance circuit comprising a resonance coil and a resonance capacitor, with a switching element, the method comprising simultaneously changing a switching frequency and a time ratio of the switching element so that the switching element satisfies a condition of zero-voltage switching when an output power of the power conversion device is changed.