Dual-Active Bridge OBC With Auxiliary Branches for Phase Flexibility
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Solution Overview
Problem
Current AC/DC converters for on-board chargers of electric vehicles lack compatibility with both three-phase and single-phase inputs, leading to inefficiencies and increased maintenance, and are not cost-effective for high-power applications.
Innovation Solution
A single-stage dual-active bridge (DAB) AC/DC converter with an auxiliary circuit featuring two branches, one connected to a single-phase input and the other to a three-phase input, utilizing energy storage and switching means to adapt operation based on input voltage levels and phases, allowing for seamless compatibility with both input types without additional load or artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single-stage dual-active bridge (DAB) AC/DC converter is designed for high-power applications, then power density and charging speed are improved, but compatibility with both three-phase and single-phase inputs becomes complex and costly
Solution Approach 1:
The patent implements a universal AC/DC converter design where the same DAB circuit topology handles both three-phase and single-phase inputs. The converter uses a unified control strategy that automatically adapts to the input type, eliminating the need for separate converter designs for different input phases. This multi-functionality approach reduces overall system complexity while maintaining high power density capabilities.
Solution Approach 2:
The patent employs dynamic switching configurations within the DAB circuit that can adapt in real-time between three-phase and single-phase operating modes. The converter dynamically adjusts its internal switching patterns and control parameters based on the detected input type, enabling seamless transition between different input configurations without requiring separate dedicated circuits for each mode.
2Reliability
If separate AC/DC converter designs are used for three-phase and single-phase inputs, then input-specific optimization is achieved, but device complexity and maintenance needs increase
Solution Approach 1:
The patent merges the previously separate three-phase and single-phase converter designs into a single unified DAB AC/DC converter. By combining the functionality of both input-type-specific converters into one integrated system with shared components and unified control logic, the patent reduces the total number of devices that need maintenance while maintaining the reliability benefits of input-specific optimization through adaptive control.
3Productivity
If high-power OBC is designed for three-phase input only, then charging power and speed are improved, but adaptability to locations without three-phase power distribution is lost
Solution Approach 1:
The patent creates a universal charger that can operate at high charging speeds with three-phase input while also maintaining full functionality with single-phase input. The unified DAB circuit and adaptive control system ensure that the charger automatically optimizes its performance based on the available input type, preserving high productivity when three-phase power is available while maintaining adaptability to locations with only single-phase power distribution.
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 provides a cost-effective, high-power density AC/DC converter with reduced maintenance needs, enabling bi-directional power flow and faster charging capabilities, compatible with both three-phase and single-phase inputs, thus enhancing the functionality and value of electric vehicles.
Implementation Method 1
an auxiliary circuit with at least two branches, comprising two switching means and energy storage means
Implementation Method 2
The switching means provide that in the single-phase input mode, the capacitor is always connected to the input which is not used for the three-phase input mode
Data Source
AI summary
The present disclosure refers to an alternating current/direct current (AC/DC) converter for an on board charger (OBC). The AC/DC converter includes a three-phase-input comprising three inputs, a single-stage dual-active bridge (DAB) circuit, and an auxiliary circuit. The auxiliary circuit includes two switching means and an energy storage means, the auxiliary circuit also includes at least two branches, wherein each of the at least two branches include one of the switching means. At least one branch of the at least two branches is connected to a single-phase AC input of the three inputs, and another branch of the at least two branches is connected to an input of the three inputs which is not a single-phase AC input, and the another branch comprises the energy storage means.