DC-DC Converter Secondary-Side Segmentation for Heat Reduction
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Solution Overview
Problem
DC-DC converters used in onboard chargers experience significant losses and heat generation due to large currents flowing through secondary-side elements, particularly in transformer coils and MOSFETs, leading to elevated temperatures.
Innovation Solution
A DC-DC converter design incorporating a DC-AC conversion circuit, multiple magnetically coupled secondary-side coils, rectifier circuits for full-wave rectification, and smoothing circuits, which reduces current flow through secondary-side elements by employing a parallel configuration and control circuitry to manage power conversion efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single secondary-side coil and rectifier circuit are used, then the device complexity is low, but the current through secondary-side elements becomes large causing high loss and temperature
Solution Approach 1:
The patent divides the secondary side into multiple independent coil-rectifier-smoothing circuit units. Each unit processes a portion of the total power, reducing the current through each individual element. This segmentation allows parallel operation where multiple circuits work simultaneously to handle the total load current, thereby reducing loss in each element while maintaining manageable device complexity through modular design.
2Temperature
If multiple secondary-side coils and rectifier circuits are used in parallel, then the current through each element is reduced, but the device complexity increases
Solution Approach 1:
The patent segments the power conversion function into multiple identical or similar circuit units operating in parallel. Each unit consists of a coil, rectifier circuit, and smoothing circuit that independently handle a portion of the power conversion task. This segmentation distributes the thermal load across multiple elements, reducing temperature in each individual component while the modular nature of the segmented design helps manage overall system complexity.
Solution Approach 2:
The patent combines multiple circuit units in parallel to achieve the desired power conversion capacity. By merging identical functional units (coil + rectifier + smoothing circuit) in parallel, the system achieves current sharing and temperature reduction while maintaining a standardized, repeatable circuit architecture that simplifies design and manufacturing processes.
3Loss of energy
If a single rectifier circuit processes the full secondary voltage, then the circuit is simple, but large current flows causing high loss and heat generation
Solution Approach 1:
The patent divides the rectification function into multiple separate rectifier circuits, each associated with its own coil and smoothing circuit. Each rectifier circuit handles only a portion of the total power, reducing the current through each rectifier element. This segmentation of the rectification function reduces energy loss in each rectifier while the total rectification capacity is maintained through the combined operation of multiple circuits.
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 configuration effectively minimizes losses and heat generation in secondary-side elements, while simplifying the primary-side circuit and reducing costs, thereby maintaining efficient power conversion and temperature control.
Implementation Method 1
The transformer includes a primary-side coil to which the primary-side AC voltage is applied, and multiple secondary-side coils magnetically coupled to the primary-side coil
Data Source
AI summary
A DC-DC converter includes a DC-AC conversion circuit, a transformer, rectifier circuits, smoothing circuits, and an output circuit. The DC-AC conversion circuit converts a DC input voltage to a primary-side AC voltage. The transformer includes a primary-side coil to which the primary-side AC voltage is applied, and secondary-side coils magnetically coupled to the primary-side coil. The rectifier circuits are provided in one-to-one correspondence with the secondary-side coils. Each of the rectifier circuits outputs a rectification voltage resulting from full-wave rectification on the secondary-side AC voltage output from the corresponding secondary-side coil out of the secondary-side coils. The smoothing circuits are provided in one-to-one correspondence with the rectifier circuits. Each of the smoothing circuits smooths the rectification voltage output from the corresponding rectifier circuit out of the rectifier circuits. The output circuit is connected to respective output terminals of the smoothing circuits. The output circuit outputs a DC output voltage.