Asymmetric DC/DC Converter Soft Switching Voltage Fluctuations
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Solution Overview
Problem
Conventional DC/DC converters face limitations in reducing power loss, especially when dealing with fluctuating voltages, such as those from storage batteries, and struggle to maintain efficiency across a wide voltage ratio between the primary and secondary power supplies.
Innovation Solution
A DC/DC converter design incorporating a transformer with a neutral point in the primary-side winding, a reactor, and bridge circuits on both sides, allowing for adjustable voltage ratios and reduced power loss through advanced switching techniques and phase shift operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the coupling type of the transformer is the same on the primary side and the secondary side, then switching loss can be reduced by soft switching technique, but the soft switching technique cannot be applied in a low output region
Solution Approach 1:
The patent applies asymmetry by configuring the transformer with different coupling types on the primary side (leakage inductance coupling) and secondary side (magnetizing inductance coupling). This asymmetric configuration allows the primary side to achieve soft switching for reducing switching loss while the secondary side can operate in different modes including low output regions where conventional symmetric soft switching cannot be applied.
Solution Approach 2:
The patent segments the transformer coupling into two independent parts: primary-side leakage inductance coupling and secondary-side magnetizing inductance coupling. This segmentation allows each side to be optimized independently - the primary side for soft switching performance and the secondary side for extended operational range including low output regions.
2Device complexity
If a conventional DC/DC converter is used, then the structure is simple, but power loss cannot be reduced effectively when voltage fluctuates
Solution Approach 1:
The patent introduces dynamic operation capabilities through the asymmetric coupled transformer configuration, enabling the converter to adapt to voltage fluctuations. The primary-side leakage inductance coupling facilitates soft switching that reduces switching loss during voltage transitions, while the secondary-side magnetizing inductance coupling maintains stable output across varying input voltages, achieving effective power loss reduction under dynamic conditions.
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 operation over a wider range of voltage ratios, effectively reducing power loss even under voltage fluctuations, enhancing efficiency and adaptability.
Implementation Method 1
a transformer having a neutral point at least in a primary-side winding
Implementation Method 2
a first reactor connected between the neutral point and a primary-side power supply
Data Source
AI summary
A reactor has one end connected to a neutral point of a transformer and the other end connected to a primary-side power supply. The transformer has almost no effective flux linkage for zero-phase current and has a phase difference between the primary side and the secondary side. A first bridge circuit and a second bridge circuit are connected to both ends of the transformer, and electric power of the primary-side power supply is controlled by the duty ratio of the first bridge circuit. The switching pattern of the second bridge circuit is phase-shifted in the leading direction and the lagging direction with reference to the switching pattern of the first bridge circuit, thereby achieving control such that soft switching operation can be performed even when the voltage ratio between the primary-side power supply and the secondary-side power supply fluctuates and the amount of transmission power is reduced.