DC-DC Converter Light Load Switch Loss Reduction
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Solution Overview
Problem
High-power bidirectional DC-DC converters for electric vehicle on-board chargers face challenges with high costs, complex hardware and software requirements, and large output ripple currents due to multi-module parallel connections, which are difficult to optimize for both cost and efficiency, especially in light load modes.
Innovation Solution
A DC-DC converter design incorporating a first and second three-phase bridge module, a resonance module, and a controller that allows for bidirectional energy transmission by adjusting frequencies and switching between high-power and low-power modes, reducing switch losses and output ripple current through a novel control method that adjusts the number of working bridge arms in light load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multi-module parallel connection mode is used to implement high-power charging, then charging power is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple bidirectional DC-DC modules into a single integrated module with unified control. The controller implements intelligent power distribution algorithms that dynamically allocate power across parallel-connected battery modules, achieving high-power charging without requiring complex external hardware interconnection circuits. This integration reduces system complexity while maintaining high power capability.
Solution Approach 2:
The controller serves multiple functions: it manages power distribution across parallel modules, performs bidirectional energy conversion control, monitors system parameters, and optimizes charging strategies. This multi-functionality eliminates the need for separate control circuits for each module, reducing overall system complexity and cost while maintaining high-power capability.
2Power
If multi-module parallel connection mode is used to implement high-power charging, then charging power is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple DC-DC conversion functions into a single modular unit with shared components. The controller manages power distribution across parallel battery modules using software algorithms rather than requiring separate hardware modules for each conversion path. This approach reduces component count, simplifies assembly, and lowers manufacturing costs while maintaining high-power charging capability.
Solution Approach 2:
The controller dynamically adjusts operating parameters such as switching frequency, duty cycle, and power distribution ratios based on real-time system conditions. This parameter optimization enables the system to achieve high-power charging efficiency without requiring oversized components, thereby reducing material costs and manufacturing expenses.
3Power
If traditional three-phase interleaved LLC resonant converter is used, then high-power charging is achieved, but output ripple current increases
Solution Approach 1:
The controller implements real-time feedback control by monitoring output current and voltage parameters. Based on this feedback, the controller dynamically adjusts switching signals to minimize ripple current while maintaining high-power transfer. The feedback mechanism enables continuous optimization of the resonant conversion process, reducing harmful ripple effects without sacrificing charging power.
Solution Approach 2:
The system employs dynamic switching strategies where the controller continuously adapts switching frequencies and phase relationships based on load conditions. This dynamic control optimizes the resonant operation across varying power levels, maintaining low ripple current throughout the operating range while achieving high-power charging capability.
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 enables higher-power charging and discharging while reducing switch losses and improving efficiency in both full-load and light load modes, achieving lower costs and smaller output ripple currents compared to traditional three-phase interleaved LLC resonant converters.
Implementation Method 1
the resonance module is configured to: resonate an output signal of the first adjustment module when the battery module of the vehicle is charged by the external, or resonate an output signal of the second adjustment module when the battery module is discharged by the external
Data Source
AI summary
A DC-DC converter includes: a first three-phase bridge module, a resonance module, a second three-phase bridge module, and a controller. The second three-phase bridge module is configured to: adjust frequency of an input signal of a battery module during discharging; and in a light load mode, the controller is configured to: control the first three-phase bridge module to switch to a two-phase bridge arm input or a one-phase bridge arm input and the second three-phase bridge module to switch to a two-phase bridge arm output, and control the second three-phase bridge module to switch to a two-phase bridge arm input or a one-phase bridge arm input and the first three-phase bridge module to switch to a two-phase bridge arm output during discharging, thereby reducing a switch loss in the light load mode.