Resonant Power Converter Mode Switching for Light-Load Efficiency
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Solution Overview
Problem
Resonant power conversion circuits face inefficiencies at low output voltages or light loads due to the need for higher switching frequencies, which compromises conversion efficiency.
Innovation Solution
A power conversion circuit that switches between pulse-frequency modulation mode for high output power conditions and pulse-width modulation mode for low output power conditions, using a control method that adjusts operation based on switching frequency and output power thresholds to optimize efficiency across a wide range of output voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If resonant power conversion circuit operates at higher switching frequency to achieve low output voltage or light load conditions, then output voltage range and load adaptability are improved, but conversion efficiency deteriorates
Solution Approach 1:
The patent implements dynamic switching between pulse-frequency modulation mode and pulse-width modulation mode based on operating conditions. The control circuit automatically selects the appropriate modulation mode according to the switching frequency and load conditions, making the system adaptable while maintaining high efficiency. This resolves the contradiction by allowing the system to be dynamic rather than static in its modulation approach.
Solution Approach 2:
The patent changes the modulation parameter (switching frequency vs. pulse width) based on operating conditions. In pulse-frequency modulation mode, the switching frequency is varied to control output voltage. In pulse-width modulation mode, the pulse width is varied while maintaining a fixed switching frequency. This parameter change strategy allows the system to achieve wide output voltage range while avoiding the efficiency penalty of high-frequency operation.
2Measurement precision
If resonant power conversion circuit uses higher switching frequency to provide low output voltage, then voltage regulation capability is improved, but conversion efficiency deteriorates
Solution Approach 1:
The control circuit dynamically switches between modulation modes based on the switching frequency. When operating in pulse-width modulation mode, the system maintains a fixed switching frequency and regulates output voltage by adjusting pulse width, thereby achieving precise voltage regulation without the efficiency penalty of high-frequency operation.
3Power
If resonant power conversion circuit operates in pulse-frequency modulation mode to achieve high output power, then power capability is improved, but conversion efficiency deteriorates at low output power
Solution Approach 1:
The patent implements dynamic mode switching based on output power level. The control circuit monitors the operating conditions and automatically transitions between pulse-frequency modulation mode (suitable for high power) and pulse-width modulation mode (suitable for low power). This dynamic adaptation ensures high conversion efficiency across the entire power range from light load to full load conditions.
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
Improves overall conversion efficiency by dynamically switching between modulation modes, ensuring high efficiency regardless of load conditions.
Implementation Method 1
The resonant capacitor and the resonant inductor determine a resonant frequency
Implementation Method 2
The transformer comprises a primary coil and a secondary coil
Data Source
AI summary
A power conversion circuit includes a transformer, a resonant capacitor, a resonant inductor, a high-side transistor, a low-side transistor, and a control circuit. The transformer includes a primary coil and a secondary coil. The primary coil, the resonant capacitor, and the resonant inductor are connected in series between a switch node and a ground. The high-side transistor provides an input voltage to a switch node based on the high-side driving signal. The low-side transistor couples the switch node to the ground based on the low-side transistor. The control circuit operates in a pulse frequency modulation mode to generate the high-side transistor and the low-side transistor with a switch frequency. When the switch frequency exceeds the first threshold, the control circuit switches from the pulse frequency modulation mode to the pulse width modulation mode.