Phase-Shifted Full-Bridge DC-DC Converter Switching for Reverse Power Flow
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Solution Overview
Problem
Phase-shifted full-bridge DC-DC converters face challenges in achieving efficient power transfer from the secondary side to the primary side when the primary-side voltage exceeds the product of the secondary-side voltage and the transformer's transformation ratio, leading to increased losses and reduced control accuracy, especially with low leakage inductance transformers.
Innovation Solution
A specialized switching pattern is introduced to control the switching elements on the secondary side, distributing current over part of the period across both switches and optimizing the switching sequence to reduce power losses and achieve high power transfer efficiency, including the use of a series inductance between specific nodes and employing a unique switching state that balances the load on switching elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the primary-side voltage exceeds the product of the secondary-side voltage and the transformer's transformation ratio, then reverse power transfer can be achieved, but power losses increase and control accuracy decreases
Solution Approach 1:
The patent changes the switching state parameters of the DC-DC converter to enable reverse power transfer. By adjusting the switching patterns and timing of the power electronic switches, the converter operates in a mode that allows power flow from secondary to primary side while maintaining controlled losses through optimized switching sequences.
Solution Approach 2:
The patent employs dynamic switching control where the switching elements are actively modulated during operation. The switching states are dynamically adjusted based on the operating conditions, allowing the system to adapt to varying voltage levels and power transfer requirements while minimizing losses through real-time optimization.
2Power
If the primary-side voltage exceeds the product of the secondary-side voltage and the transformer's transformation ratio, then reverse power transfer can be achieved, but control accuracy requirements increase
Solution Approach 1:
The patent modifies control parameters including switching frequencies, duty cycles, and phase shifts to enable accurate control during reverse power transfer. By adjusting these parameters, the system maintains precise control even when operating outside the conventional voltage relationship, reducing the stringency of control signal accuracy requirements.
3Loss of energy
If a specialized switching pattern is introduced to reduce RMS current waveform, then power loss in secondary-side switches is reduced, but device complexity increases
Solution Approach 1:
The patent implements a periodic switching pattern where the secondary-side switches are activated in a repeating sequence. This periodic action distributes the current waveform over time, reducing the RMS current and associated power losses. The pattern involves alternating between different switching states in a cyclic manner, achieving loss reduction through time-based current distribution.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the switching states and patterns before actual power transfer occurs. The switching sequence is planned and executed in advance, optimizing the current distribution across secondary-side switches to minimize losses before the high-load conditions occur.
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 enables high power transfer efficiency in the reverse direction while reducing overall losses, particularly in the secondary switches, and minimizes the requirements for control accuracy, especially at high loads and small phase offsets, thereby enhancing the performance of phase-shifted full-bridge DC-DC converters.
Implementation Method 1
at least one transformer (50) for galvanic isolation of the two vehicle electrical systems
Data Source
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AI summary
The present invention relates to a power transmission in a DC-DC converter, in particular a phase-shifted full-bridge DC-DC converter from the secondary side to the primary side. In particular, an additional switching state which can reduce the power dissipation of the switching elements in the DC-DC converter, is provided.