PFC and SR Converter Mode Control for Lower Power Loss
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Solution Overview
Problem
Existing power conversion methods face challenges in minimizing losses associated with power conversion, particularly in applications like electric vehicle battery charging, where efficient conversion of input voltages into output voltages is crucial.
Innovation Solution
A power conversion method involving a PFC converter and an SR converter, where the PFC converter receives three input voltages and generates a DC link voltage, and the SR converter operates in buck, series resonant, or boost modes based on output voltage demands, with a control circuit managing the operating modes to regulate the DC link voltage and optimize power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single power converter is used for power conversion, then the device complexity is low, but the power losses increase and efficiency decreases
Solution Approach 1:
The power conversion system is divided into two separate converters: a PFC converter and an SR converter. The PFC converter handles power factor correction and initial power conversion, while the SR converter handles series resonant power transfer. This segmentation allows each converter to be optimized for its specific function, reducing overall power losses while distributing the complexity across specialized components rather than requiring a single complex converter.
2Adaptability or versatility
If the SR converter operates in fixed mode, then the control complexity is low, but the adaptability to different output voltage requirements decreases
Solution Approach 1:
The SR converter is designed to dynamically switch between two operating modes: buck mode and series resonant mode. The control circuit monitors output voltage requirements and automatically transitions between modes as needed. This dynamic operation enables the system to adapt to varying output voltage demands while maintaining relatively simple control logic through well-defined mode transition criteria.
Solution Approach 2:
The system changes its operating parameters by switching between different converter modes based on output voltage requirements. When high voltage step-down is needed, the buck mode is activated; when resonant power transfer is required, the SR mode is activated. This parameter-based control approach provides adaptability without requiring complex real-time adjustments within each mode.
3Loss of energy
If the PFC converter operates in single mode, then the control simplicity is high, but the efficiency under varying load conditions decreases
Solution Approach 1:
The system segments the power conversion function into two specialized converters rather than requiring the PFC converter to handle all operating conditions alone. The PFC converter focuses on power factor correction and initial conversion, while the SR converter handles the series resonant power transfer and output voltage regulation. This segmentation improves overall efficiency across varying load conditions while keeping each converter's control relatively simple.
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
This approach reduces power losses by dynamically adjusting operating modes of the SR converter based on output voltage requirements, enhancing efficiency and adaptability in power conversion applications.
Implementation Method 1
operating an SR (Series Resonant) converter coupled to the PFC converter via the DC link nodes in one of at least two different operating modes dependent on an output voltage of the SR converter
Data Source
AI summary
A power conversion method is disclosed. The method includes operating a PFC converter configured to receive three input voltages and provide a DC link voltage between DC link nodes in one of at least two different operating modes, and operating an SR converter coupled to the PFC converter via the DC link nodes in one of at least two different operating modes dependent on an output voltage of the SR converter. Operating the SR converter includes regulating a voltage level of the DC link voltage dependent on a DC link voltage reference, and the at least two different operating modes of the SR converter include a buck mode and a series resonant mode.