Resonant Power Converter Frequency Modulation for Voltage Gain
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Solution Overview
Problem
Conventional resonant power convertors face limitations in switching frequency, leading to insufficient output voltage and inefficiency in meeting energy efficiency regulations due to hard-switching mechanisms, particularly under peak loads or when feedback is out of control.
Innovation Solution
A resonant power converting circuit that adjusts the lowest switching frequency based on output current, utilizing a control unit, current detecting unit, and frequency modulation unit to modulate the switching frequency range, ensuring optimal voltage gain across varying load conditions and preventing overvoltage protection triggers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the switching frequency is increased to improve output voltage, then the output voltage becomes sufficient, but the switching loss increases and power converting efficiency decreases
Solution Approach 1:
The patent implements dynamic switching frequency adjustment by detecting output current and modulating the switching frequency accordingly. The controller dynamically changes the switching frequency within a range (e.g., 20-100 kHz) based on load conditions, allowing the system to operate at lower frequencies during light loads to reduce switching loss while maintaining sufficient output voltage during peak loads.
Solution Approach 2:
The patent changes the switching frequency parameter dynamically based on output current detection. By modulating the switching frequency between minimum and maximum values according to load demands, the system optimizes the trade-off between output voltage sufficiency and switching loss minimization, improving overall power converting efficiency.
2Loss of energy
If the switching frequency is decreased to reduce switching loss, then power converting efficiency improves, but the output voltage becomes insufficient
Solution Approach 1:
The system dynamically adjusts switching frequency based on real-time output current detection. During peak load periods when output voltage demand is high, the controller increases switching frequency to ensure sufficient output voltage. During light load periods, it decreases frequency to minimize switching loss, thus resolving the contradiction between voltage sufficiency and efficiency.
Solution Approach 2:
The patent modulates the switching frequency parameter within a specific range (e.g., 20-100 kHz) according to load conditions. This parameter change strategy allows the system to achieve high efficiency at light loads while maintaining adequate output voltage at heavy loads, effectively resolving the voltage-efficiency trade-off.
3Ease of operation
If conventional PWM control is used to maintain fixed switching frequency, then control simplicity is maintained, but voltage gain is limited and output voltage becomes insufficient under peak loads
Solution Approach 1:
The patent transitions from fixed-frequency PWM control to dynamic frequency modulation while maintaining relatively simple control architecture. The controller detects output current and automatically adjusts switching frequency within a predefined range, achieving sufficient output voltage under peak loads without significantly complicating the control system.
Solution Approach 2:
The system changes the switching frequency parameter based on output current detection, enabling voltage gain enhancement under peak load conditions. This parameter modulation approach maintains control simplicity while effectively resolving the output voltage insufficiency issue that plagues conventional fixed-frequency PWM controllers.
4Device complexity
If hard-switching mechanism is used to simplify circuit design, then device complexity is reduced, but switching loss increases and energy efficiency decreases
Solution Approach 1:
The patent implements dynamic switching frequency adjustment that enables soft-switching conditions to be achieved more easily. By modulating frequency based on load conditions, the system creates favorable conditions for reduced switching loss without requiring complex soft-switching circuit topologies, thus maintaining relatively simple circuit design while improving efficiency.
Data Source
AI summary
A resonant power converting circuit is provided, which includes a resonant converting unit, a control unit, a current detecting unit and a frequency modulation unit. The control unit outputs switching signals to the resonant converting unit to adjust an output thereof. The current detecting unit is configured to detect an output current of the resonant converting unit. The frequency modulation unit may adjust a lowest switching frequency of the control unit according to the detected output current so as to increase a gain of the resonant converting unit and an output stability of the resonant converting unit.