DC-DC Converter Volume Reduction via Time-Division Dual Transformers
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Solution Overview
Problem
Existing isolated DC-DC power converters with full-bridge phase-shift circuits face efficiency losses under light loads and high circulating losses under heavy loads, and the dual-transformer configuration results in a large volume and poor power density due to the need for transformers with matched power levels.
Innovation Solution
A DC-DC power conversion apparatus and method utilizing a switching circuit, main and auxiliary transformer circuits, and rectifier circuits that provide input power by time-division to primary windings, allowing the main and auxiliary transformers to share power during both transmitting and freewheeling periods, enabling the use of smaller transformers and reducing volume while maintaining soft-switch effects across the full load range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a full-bridge phase-shift circuit structure is used, then zero-voltage switching can be achieved, but the soft-switch effect is lost under light load and circulating loss increases under heavy load
Solution Approach 1:
The patent applies dynamics by making the circuit configuration adjustable based on load conditions. The controller dynamically switches between full-bridge phase-shift mode (for heavy loads) and push-pull mode (for light loads), allowing the system to adapt its characteristics to maintain soft-switching effect and minimize circulating losses across the full load range
Solution Approach 2:
The patent changes the operational parameters of the circuit by switching between different circuit configurations. The controller monitors load conditions and changes the circuit topology parameters - using full-bridge phase-shift for heavy loads and push-pull for light loads - thereby optimizing performance across varying operating conditions
2Reliability
If a dual-transformer configuration is used, then soft-switch effect can be achieved across full load range, but the volume increases and power density decreases
Solution Approach 1:
The patent segments the transformer function into two separate single-phase transformers instead of using one large dual-winding transformer. Each transformer handles a portion of the power, allowing them to be physically smaller and enabling the system to achieve soft-switching across the full load range without requiring a large volume
Solution Approach 2:
The patent merges the functions of two separate single-phase transformers to achieve the performance characteristics of a larger dual-winding transformer. By combining the output of both transformers, the system achieves full-load soft-switching capability while using smaller individual components that occupy less total volume
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 the volume of the power conversion apparatus by 20% and improves power density without compromising the soft-switch effect, while also decreasing circulating losses and maintaining efficient power delivery across the full load range.
Implementation Method 1
The switching circuit is coupled to a primary winding of the main transformer circuit and a primary winding of the auxiliary transformer circuit
Implementation Method 2
An AC input terminal of the main rectifier circuit is coupled to a secondary winding of the main transformer circuit
Data Source
AI summary
A DC-DC power conversion apparatus and a DC-DC power conversion method are provided. The DC-DC power conversion apparatus includes a switching circuit, a main transformer circuit, a main rectifier circuit, an auxiliary transformer circuit and an auxiliary rectifier circuit. The switching circuit provides an input power to a primary winding of the main transformer circuit or a primary winding of the auxiliary transformer circuit by time-division. An AC input terminal of the main rectifier circuit is coupled to a secondary winding of the main transformer circuit. An AC input terminal of the auxiliary rectifier circuit is coupled to a secondary winding of the auxiliary transformer circuit. A power output terminal of the auxiliary rectifier circuit is coupled to a reference voltage terminal of the main rectifier circuit for lifting a voltage of the power output terminal of the main rectifier circuit.