Common-Core Resonant PFC Converter for Low-Voltage Output
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Solution Overview
Problem
Existing power factor correction converters require complex control circuits and high-voltage components, leading to increased cost, volume, and electromagnetic interference, and are not suitable for low-voltage outputs.
Innovation Solution
A common-core power factor correction resonant converter using a coupling inductor, charge-storage capacitor, and diodes, which operates through switching to reduce voltage conversion loss, cost, and volume, while maintaining a good power factor and minimizing electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If boost topology control architecture is used for power factor correction, then power factor correction effect is achieved, but output voltage must be higher than line power source voltage making it unsuitable for low-voltage output
Solution Approach 1:
The patent inverts the conventional boost topology by using a resonant tank circuit with capacitor and inductor to achieve voltage transformation in the opposite direction, enabling low-voltage output from high-voltage line input while maintaining power factor correction functionality
Solution Approach 2:
The patent changes the operating parameters by introducing resonant frequency operation and soft switching modes, allowing the converter to operate efficiently at low output voltages while maintaining high power factor through parameter optimization rather than topological complexity
2Adaptability or versatility
If complex control circuits such as analog multiplier are used to generate high power factor, then power factor correction is improved, but device complexity and cost increase
Solution Approach 1:
The resonant tank circuit automatically generates the necessary current waveforms and voltage relationships through its natural resonant operation, eliminating the need for external analog multipliers or complex control circuits to achieve high power factor correction
Solution Approach 2:
The patent utilizes periodic resonant oscillations at the resonant frequency of the tank circuit to naturally shape the input current waveform to match the voltage waveform, achieving high power factor through periodic energy exchange rather than complex control
3Object-affected harmful factors
If frequency jitter, quasi resonant, or valley switching circuits are introduced to reduce EMI, then electromagnetic interference is reduced, but device complexity increases
Solution Approach 1:
The patent employs resonant oscillation at a specific frequency to create a controlled vibratory energy transfer mechanism that naturally limits electromagnetic radiation and reduces EMI without requiring additional frequency modulation or valley switching circuits
Solution Approach 2:
The resonant energy oscillation that could potentially cause EMI is converted into a beneficial soft switching mechanism that reduces voltage spikes and current surges, transforming the potential harmful high-frequency content into a controlled energy transfer process
4Reliability
If two separate inductors and five diodes are used in power factor correction resonant converter, then soft switching operation is achieved, but cost, volume, and component conduction loss increase
Solution Approach 1:
The patent merges the functions of multiple inductors into a single resonant inductor and combines diode functions into fewer components by utilizing the resonant tank's natural characteristics, reducing the total component count while maintaining soft switching operation
Solution Approach 2:
The resonant inductor and capacitor serve multiple functions simultaneously: energy storage, voltage transformation, current shaping for power factor correction, and soft switching generation, eliminating the need for separate dedicated components for each function
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 solution reduces the cost and volume of circuit elements, allows for the use of low-voltage components, and achieves a better power factor with reduced electromagnetic interference and voltage conversion loss.
Implementation Method 1
a coupling inductor, a charge-storage capacitor, a switch, a first diode, and a second diode... when the switch is on in response to the control signal, the coupling inductor and the charge-storage capacitor are charged by the input line voltage
Implementation Method 2
a charge-storage capacitor... when the switch is on in response to the control signal, the coupling inductor and the charge-storage capacitor are charged by the input line voltage, and then when the switch is off in response to the control signal, the coupling inductor and the charge-storage capacitor are discharged to provide the output power
Implementation Method 3
A common-core power factor correction resonant converter... achieves a better power factor with reduced electromagnetic interference
Data Source
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AI summary
A common-core power factor correction resonant converter includes an energy-transforming circuit. The energy-transforming circuit receives an input line voltage and generates an output power. The energy-transforming circuit includes a coupling inductor and a charge-storage capacitor. The coupling inductor and the charge-storage capacitor are charged by the input line voltage in response to a control signal, so as to generate a charge-storage capacitor voltage. When the charge-storage capacitor voltage is charged to a preset voltage level, the coupling inductor and the charge-storage capacitor are discharged according to the control signal. Then, the energy in the coupling inductor and the charge-storage capacitor is transformed to the output load and provide the output voltage or current regulation.