Bidirectional LLC Power Converter With Hybrid Rectifier-Inverter Stage
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Solution Overview
Problem
Conventional power conversion systems lack efficient bidirectional power transfer capabilities between AC and DC sources, particularly in applications requiring high efficiency and unity power factor, especially in systems connected to batteries.
Innovation Solution
A bidirectional power conversion system utilizing a full-bridge LLC converter with magnetically coupled switching networks, a hybrid power device comprising switches and diodes, and a power factor correction device, which configures as a diode rectifier for AC to DC conversion and as an inverter for DC to AC conversion, with a relay to adjust the system configuration based on input voltage thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional AC/DC stage with separate diode rectifier and power factor correction circuit is used, then the power factor can be corrected to unity, but the system lacks bidirectional power transfer capability and requires more components
Solution Approach 1:
The hybrid power device is designed to perform multiple functions: it operates as a diode rectifier during AC-to-DC conversion and as an inverter during DC-to-AC conversion. This multi-functionality eliminates the need for separate dedicated rectifier and inverter circuits, thereby enabling bidirectional power transfer while reducing overall system complexity
Solution Approach 2:
The patent combines the rectifier and inverter functions into a single hybrid power device with magnetically coupled switching networks. By merging these functions and utilizing the magnetic coupling between primary and secondary switching networks, the system achieves bidirectional operation with fewer components
2Loss of energy
If a full-bridge LLC converter with hybrid power device is used, then bidirectional power transfer efficiency is improved, but the control complexity increases
Solution Approach 1:
The control circuit monitors the operating mode (AC-to-DC or DC-to-AC) and automatically adjusts the switching sequences and control parameters of the hybrid power device. This feedback-based adaptive control optimizes power conversion efficiency in both directions while managing control complexity through automated adjustment
Solution Approach 2:
The system dynamically switches between different operating modes by changing the switching sequences of the hybrid power device. The control circuit adapts the switching patterns based on the desired power flow direction, enabling efficient bidirectional operation without requiring entirely separate control circuits for each mode
3Ease of manufacture
If separate dedicated rectifier and inverter circuits are used, then the system design is simpler, but bidirectional power transfer requires two separate systems
Solution Approach 1:
The hybrid power device is designed as a universal component that can operate in both rectifier and inverter modes. By integrating both functions into a single device with magnetically coupled switching networks, the system achieves bidirectional power transfer capability without requiring two separate dedicated systems, thus maintaining ease of manufacture while enhancing versatility
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 system achieves high-efficiency bidirectional power conversion with unity power factor, efficiently handling both active and reactive power transfers, and is suitable for applications such as electric vehicle charging and battery management.
Implementation Method 1
a first switching network and a second switching network magnetically coupled to each other
Data Source
AI summary
A bidirectional power conversion system includes an isolated power converter having a first input connected to an output of a diode rectifier and a second input connected to an output of a power factor correction device. The power conversion system further comprises a plurality of switches and a plurality of diodes configured such that the plurality of switches and the plurality of diodes form the diode rectifier and the power factor correction device when the system is configured to deliver power from an AC power source to a DC load and the plurality of switches forms an inverter when the system is configured to deliver power from a DC power source to an AC load.