Resonant Converter Circuitry for Lower Switch Voltage Stress
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Solution Overview
Problem
Existing power conversion circuits in electric vehicles face challenges with high voltage stress on semiconductor switches, leading to increased costs and complexity, particularly in high-power applications.
Innovation Solution
A resonant converter system comprising a first conversion circuit, a resonant transformer circuit, and a switching circuit that allows for flexible operation by selectively changing connection positions of bridge arm units, using either bridge arm units or multi-level switching elements to convert voltages, and includes a state selection circuit for series or parallel connection of resonant converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional power conversion circuits are used to handle high power and high output voltage requirements, then the power conversion capability is improved, but the semiconductor switch voltage stress increases and costs increase
Solution Approach 1:
The power conversion circuit is divided into multiple bridge arm units (first bridge arm units and second bridge arm units) that operate in a segmented manner. The resonant converter uses a multi-bridge arm configuration where different bridge arms can be selectively activated, distributing the voltage stress across multiple switches rather than concentrating it on single switches handling the full high voltage.
Solution Approach 2:
A resonant transformer circuit is introduced as an intermediary component between the bridge arm units and the output. This resonant transformer provides galvanic isolation and voltage transformation, allowing the semiconductor switches to operate at lower voltage levels while still achieving high output voltage through the transformer's turns ratio, thereby reducing voltage stress on the switches.
2Power
If conventional power conversion circuits are used to handle high power requirements, then the power conversion capability is improved, but the system complexity increases
Solution Approach 1:
The resonant converter design uses universal bridge arm units that can perform multiple functions. The same bridge arm units are used for both voltage generation and resonant operation, and the resonant transformer serves both as an isolation component and a voltage transformation component. This multi-functionality reduces the need for separate dedicated components, thereby managing system complexity while achieving high power conversion capability.
Solution Approach 2:
The converter employs dynamic switching control where the connection positions of the second bridge arm units are selectively changed during operation. This dynamic reconfiguration allows the circuit to adapt to different operating conditions and power levels, optimizing performance across a wide range while maintaining manageable complexity through controlled flexibility rather than fixed complex circuitry.
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 system reduces cross-voltage stress on semiconductor switches, simplifies circuit design, and enhances flexibility in voltage output range and load handling, while maintaining high efficiency and reducing power consumption.
Implementation Method 1
The resonant transformer circuit is coupled to the plurality of first bridge arm units, and is configured to convert the first voltage into a second voltage
Implementation Method 2
A resonant converter comprising a first conversion circuit, a resonant transformer circuit, a second conversion circuit and a switching circuit
Data Source
AI summary
A resonant converter includes a first conversion circuit, a resonant transformer circuit, a second conversion circuit and a switching circuit. The resonant transformer circuit is coupled to multiple first bridge arm units of the first conversion circuit, and is configured to convert a first voltage into a second voltage. The second conversion circuit includes multiple second bridge arm units and multiple multi-level switching elements. The switching circuit is coupled to the second conversion circuit to selectively change connection positions of the second bridge arm units, so that the second conversion circuit converts the second voltage into a first DC (direct current) power by the second bridge arm units instead of by the multi-level switching elements, or the second conversion circuit converts the second voltage into a second DC (direct current) power by the second bridge arm units and multi-level switching elements.