Resonant Power Conversion for Wide-Voltage EV Charging
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Solution Overview
Problem
Current electric vehicle charging systems have limited input and output voltage ranges, low efficiency, and are unable to meet the growing need for bidirectional power transmission and energy storage applications, restricting their application and functionality.
Innovation Solution
A power conversion device comprising a first and second power converter, a resonant converter with an isolation transformer, and a controller that controls the converters to perform AC-to-DC, DC-to-DC, and bidirectional power conversions, operating at a predetermined resonant frequency to expand voltage ranges and enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional charger or charging system is used, then the system can perform basic charging functions, but the input and output voltage ranges are limited and efficiency is low when operating across great voltage ranges
Solution Approach 1:
The charging system is divided into multiple independent power conversion modules, each optimized for specific voltage ranges. This segmentation allows the system to handle a broader overall voltage range while maintaining high efficiency in each segment by selecting the appropriate module for the current operating conditions.
Solution Approach 2:
The system dynamically switches between different power conversion modes and configurations based on real-time voltage conditions. This dynamic adaptation enables the system to maintain optimal efficiency across varying voltage ranges by adjusting the conversion path and parameters according to the specific operating point.
2Adaptability or versatility
If a conventional charger or charging system is used, then the system has a simple structure, but it cannot perform bidirectional power transmission or meet new functions such as stabilizing the grid and assisting in power generation and energy storage
Solution Approach 1:
The power conversion device is designed with multi-functional capabilities, incorporating bidirectional power flow control, grid stabilization functions, and energy storage integration. A single unified platform performs multiple functions that would traditionally require separate systems, achieving versatility without proportionally increasing complexity.
Solution Approach 2:
The system introduces intelligent control units and interface modules that act as intermediaries between different functional components. These intermediaries manage the complexity of bidirectional power transmission and grid interaction while presenting a simplified interface to the user and external systems.
3Adaptability or versatility
If the charging system operates across a great voltage range, then it can accommodate more applications, but the efficiency becomes quite low
Solution Approach 1:
The system changes operating parameters such as switching frequency, pulse width modulation duty cycle, and conversion topology based on the voltage range and power level. This parameter adaptation allows the system to maintain high efficiency across different voltage conditions by optimizing the conversion process for each specific operating point.
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 significantly expands the input and output voltage ranges, improves efficiency, and enables bidirectional power transmission, allowing the charging system to support various applications, including vehicle-to-grid functionality and energy storage, while maintaining high efficiency and flexibility.
Implementation Method 1
control the resonant converter to operate at a predetermined resonant frequency to perform conversion between the second DC voltage and a third DC voltage
Data Source
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AI summary
Embodiments of the present disclosure provide a power conversion device, an electric vehicle charging system, and a method of controlling the power conversion device. The power conversion device includes: a first power converter and a second power converter; a resonant converter coupled between the first power converter and the second power converter; and a controller configured to: control, based on voltage information associated with the power conversion device, the first power converter to perform conversion between an AC voltage or a first DC voltage and a second DC voltage; control the resonant converter to operate at a predetermined resonant frequency to perform conversion between the second DC voltage and a third DC voltage; and control, based on the voltage information, the second power converter to perform conversion between the third DC voltage and a fourth DC voltage. The solution the present disclosure can improve the efficiency of the power conversion device and the charging system, and expanding the application range and the scenarios.