Isolated DC/DC Converter With Dual-Mode Voltage Matching
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Solution Overview
Problem
Existing isolated DC/DC converters face efficiency losses due to deviations from the ideal transformer turn ratio caused by varying input and output voltages, necessitating complex voltage variation stages.
Innovation Solution
A DC/DC converter design with a capacitor series, half-bridges, and a three-phase transformer, utilizing two operating modes to accommodate varying input and output voltage ratios, achieving optimal efficiency across a broader range of voltage ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the converter uses a fixed transformer turn ratio, then efficiency is optimized at one specific voltage ratio, but efficiency deteriorates when input/output voltages vary
Solution Approach 1:
The patent implements dynamic adaptability by enabling the converter to switch between two operating modes with different effective input voltages (VDC and VDC/2). This dynamic switching capability allows the converter to adapt to varying voltage ratios without requiring a separate voltage variation stage, thereby maintaining high efficiency across a broader range of operating conditions while avoiding the complexity of additional circuitry
2Adaptability or versatility
If the converter adds a separate voltage variation stage to handle varying voltages, then voltage adaptability is improved, but device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by enabling the existing converter circuitry to operate in two distinct modes without adding dedicated voltage variation components. The same half-bridge circuit and transformer structure serve both the full-voltage mode and the half-voltage mode, eliminating the need for separate buck/boost or PFC stages while maintaining the ability to handle varying input and output voltages effectively
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 converter maintains high efficiency by adaptively switching between two or three voltage levels, allowing operation with two different effective input voltages, thereby enhancing efficiency for a wider range of voltage ratios compared to conventional converters.
Implementation Method 1
They typically consist of an input stage, isolation stage, and output stage. The input stage converts the input voltage to an AC voltage, which is then transferred through the isolation stage using a transformer.
Implementation Method 2
The control circuit is configured to operate the semiconductor switches of the half-bridges to create an AC voltage on the primary side of the transformer using a first operating mode and a second operating mode.
Implementation Method 3
The output stage then rectifies and possibly filters the received AC voltage to provide the desired output voltage.
Data Source
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AI summary
An isolated DC/DC power converter arranged for power conversion between prima-ry side DC terminals and secondary side DC terminals, comprising: - a capacitor series of two capacitors arranged between the primary side DC termi-nals of the power converter, - three first half-bridges of two semiconductor switches each, the half-bridges being arranged in a parallel connection between the upper primary side DC terminal and the midpoint of the capacitors, - three second half-bridges of two semiconductor switches each, each second half bridge being connected between the lower primary side DC terminal and the mid-point of a respective first half-bridge, - a three-phase transformer, its primary side being connected to the midpoints of the second half-bridges, - a rectifier circuit connected to the secondary side of the transformer, - a control circuit configured to -- operate the semiconductor switches of the half-bridges to create an AC voltage on the primary side of the transformer using a first operating mode and a second operating mode, -- in the first operating mode, create the AC voltage by alternating between two or more voltage levels at the midpoints of the second half-bridges that include the voltages at the primary side DC terminals, -- in the second operating mode, create the AC voltage by alternating between two voltage levels at the midpoints of the second half-bridges that have a voltage differ-ence of half the voltage between the primary side DC terminals.