Bidirectional Power Adapter with Bridgeless PFC
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Solution Overview
Problem
Existing power transmission systems for electric vehicles face challenges in efficiently managing bidirectional power flow while minimizing harmonic content and electromagnetic interference, particularly in high-output kW range applications, where additional power factor correction (PFC) stages are costly and inefficient.
Innovation Solution
An adapter device with a mode-setting device that allows bidirectional power transmission by configuring switching devices and inductances to operate as either an AC-DC or DC-AC converter, using Si-MOSFETs and IGBTs to achieve bridgeless PFC operation without the need for expensive SiC-MOSFETs, enabling efficient energy transfer and reduced losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a PFC circuit is connected between the rectifier and the capacitor to prevent harmonic content, then the grid input current becomes sinusoidal and has minimal phase shift, but the device complexity and cost increase due to additional hardware requirements
Solution Approach 1:
The patent combines the PFC functionality with the existing bridge rectifier by using the same switching devices and inductances for both rectification and power factor correction. The first and second bridge branches with their switching devices (first through fourth switching devices) and inductances (first and second inductances) perform dual functions of rectifying AC to DC and simultaneously correcting the power factor by controlling current waveform to be sinusoidal and in phase with voltage.
Solution Approach 2:
The adapter device is designed to perform multiple functions using the same hardware components. The bridge branches with switching devices and inductances serve both as rectifiers and PFC circuits. The mode-setting device enables the system to operate in different modes (AC-DC conversion, DC-AC conversion, bidirectional power flow) without requiring additional dedicated hardware for each function.
2Loss of energy
If expensive SiC-MOSFETs are used to achieve efficient bidirectional power transmission, then power loss is reduced and efficiency is improved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent uses conventional, cost-effective Si-MOSFETs and IGBTs instead of expensive SiC-MOSFETs. The switching devices (first through fourth switching devices) are implemented using standard silicon-based technology that is widely available and economically viable, while still achieving efficient bidirectional power transmission through proper control strategies and circuit topology.
Solution Approach 2:
The patent optimizes the operating parameters and control strategies for the switching devices to maximize efficiency with conventional components. By adjusting switching frequencies, duty cycles, and control patterns, the system achieves low power loss and high efficiency bidirectional transmission using affordable Si-MOSFETs and IGBTs, compensating for the lower inherent efficiency of these materials through intelligent control.
3Object-affected harmful factors
If additional PFC stages are added to minimize harmonic content in high-output kW range applications, then electromagnetic emissions are reduced, but the device size and weight increase
Solution Approach 1:
The patent merges the PFC functionality with the bridge rectifier structure, eliminating the need for separate additional PFC stages. The same inductances (first and second inductances) and switching devices used for rectification also perform power factor correction, thereby reducing electromagnetic emissions and minimizing harmonic content without adding extra components that would increase weight and size.
4Adaptability or versatility
If the adapter device supports bidirectional power transmission with mode-setting device, then versatility and adaptability are improved, but the control complexity increases
Solution Approach 1:
The patent implements dynamic control capabilities through the mode-setting device that can switch between different operating modes (AC-DC conversion, DC-AC conversion, bidirectional power flow). The control system dynamically adjusts the switching patterns of the first through fourth switching devices based on the desired mode of operation, enabling versatile bidirectional functionality while managing control complexity through structured mode-based control strategies.
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 adapter device enables efficient bidirectional power transmission with reduced harmonic content and electromagnetic interference, saving costs by using conventional Si-MOSFETs and IGBTs, and allowing the PFC circuit to operate without additional hardware for reverse power flow, thus enhancing energy efficiency and compatibility.
Implementation Method 1
a first bridge branch (203a) and a second bridge branch (203b) which form a full bridge (203)
Data Source
AI summary
An adapter device, including an AC connection including first AC contact and second AC contact; a DC connection including first DC contact and second DC contact; a first bridge branch including first switching device and second switching device, the first switching device and second switching device connected in series at a first bridge point, the first bridge point connected to first AC contact; a second bridge branch including third switching device and fourth switching device, third switching device and fourth switching device connected in series at a second bridge point, the second bridge point connected to second AC contact; and mode-setting device configured to predetermine a direction of power flow between AC connection and/or DC connection, first bridge branch and second bridge branch connected in parallel to the first DC contact and second DC contact, and different types of switching devices used as switching devices of a bridge branch.