Mixed DAB and LLC Converter Control for Wide-Range Efficiency
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Solution Overview
Problem
Existing power converters, such as dual active bridge (DAB) and LLC resonant converters, face challenges in maintaining high power transfer efficiency over a wide voltage range, particularly in low output voltage ranges where efficiency is constrained by voltage gain and total inductance.
Innovation Solution
The proposed method involves a common power converter system comprising a plurality of power converters, where the number and type of power converters are determined based on electrical parameters to achieve a desired ratio of power converter types. This system operates by activating specific power converters and adjusting their switching frequencies to maintain optimal efficiency across a wide voltage range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dual active bridge (DAB) converter is used to support a wide voltage range, then the voltage range capability is improved, but the power efficiency deteriorates sharply in low output voltage range
Solution Approach 1:
The power converter system is divided into multiple DAB converter modules that can be selectively activated. Each module operates independently, allowing the system to segment the overall power conversion task into smaller units that can maintain higher efficiency at different voltage levels.
Solution Approach 2:
The system dynamically determines the number and type of power converters to activate based on real-time electrical parameters such as input voltage, output voltage, and power demand. This dynamic adaptation allows the system to optimize efficiency for the current operating conditions while maintaining wide voltage range capability.
2Loss of energy
If an LLC resonant converter is used to improve power efficiency, then the power efficiency is improved at optimal operation point, but the output voltage variability deteriorates
Solution Approach 1:
The system employs multiple types of power converter modules (DAB and LLC) that can be selectively activated based on operating conditions. This multi-functionality allows the system to use LLC converters for high-efficiency operation at optimal points while switching to DAB converters when wide voltage range is required, combining the advantages of both converter types.
Solution Approach 2:
The controller changes operational parameters including the type and number of activated converters based on electrical conditions. By monitoring input voltage, output voltage, and power demand, the system adjusts which converter modules are active, enabling it to maintain high efficiency across a wide voltage range rather than being constrained to a narrow optimal operating point.
3Loss of energy
If the number of power converters is increased to maintain efficiency over wide voltage range, then the power efficiency is improved, but the device complexity increases
Solution Approach 1:
Instead of activating all available power converter modules simultaneously, the system activates only the necessary number and type of modules based on current electrical parameters. This partial action approach maintains high efficiency by ensuring each active converter operates in its optimal range, while avoiding the unnecessary complexity and losses that would result from operating all converters at suboptimal conditions.
Data Source
AI summary
The present disclosure relates to a method for power control of a common power converter including a plurality of power converters. The method includes: determining a number of power converters of the plurality of power converters to be activated; determining, based on the at least one electrical parameter of the plurality of power converters and/or the determined number of power converters to be activated, a ratio of a number of at least one power converter of a first type of the plurality of power converters and a number of at least one power converter of a second type of the plurality of power converters; and operating the plurality of power converters based on the determined number of power converters and the ratio. The present disclosure also relates to a corresponding controller and system.