Universal AC/DC Converter for EV Onboard Charging
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Solution Overview
Problem
Existing onboard charger systems for electric and hybrid vehicles are inefficient and costly due to the need for multiple converters to handle both three-phase and single-phase power grids, with low single-phase efficiency and increased component count.
Innovation Solution
A compact electric charger system comprising a three-phase alternating-direct converter with two direct-direct converter circuits connected in series and parallel, allowing for efficient operation in both three-phase and single-phase modes with reduced component count and improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If three AC/DC single-phase alternating-direct converters are used to charge from single-phase or three-phase power grids, then charging flexibility and electrical performance are improved, but the number of components and system cost increase considerably
Solution Approach 1:
The patent implements a universal AC/DC converter that can operate in both single-phase and three-phase modes through a single integrated circuit design. The converter uses three bridge legs with switchable connections that allow the same hardware to adapt to different power grid configurations, eliminating the need for separate single-phase and three-phase converter units.
Solution Approach 2:
The converter is divided into three independent bridge legs that can be selectively activated. Each bridge leg can operate independently or in combination with others, allowing the system to function in single-phase mode (using one or two legs) or three-phase mode (using all three legs), providing flexibility without requiring complete separate converter systems.
2Device complexity
If a single three-phase alternating-direct converter is used to improve compactness, then device complexity is reduced, but single-phase efficiency becomes very low as only two branches are used operating at one third of theoretical power
Solution Approach 1:
The converter employs dynamic switching mechanisms that allow the system to reconfigure its operational mode based on the input power phase. Control circuitry dynamically adjusts the switching patterns of the bridge legs to optimize performance for either single-phase or three-phase operation, enabling the single-phase mode to utilize all three bridge legs effectively rather than being limited to two branches.
3Adaptability or versatility
If multiple converters are used to handle both power grid types, then adaptability is improved, but the bulk and cost of the electrical system increase
Solution Approach 1:
The patent merges the functionality of separate single-phase and three-phase converters into a single integrated AC/DC converter unit. By combining the bridge legs and control logic into one unified system, the patent achieves power grid compatibility for both single-phase and three-phase inputs while significantly reducing the overall bulk and component quantity compared to using multiple separate converters.
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 and compactness by using a single control unit for both the alternating-direct converter and direct-direct converter parts, with interleaving and phase-shifting configurations, reducing ripple current and noise, and allowing for balanced operation in both power grid scenarios.
Implementation Method 1
an alternating-direct converter and a direct-direct converter, preferably galvanically isolated. The alternating-direct converter is generally called a power factor correction (PFC) alternating-direct converter
Implementation Method 2
a direct-direct converter, said direct-direct converter having two direct-direct converter circuits
Implementation Method 3
with interleaving and phase-shifting configurations, reducing ripple current and noise
Data Source
AI summary
An electric system to charge a battery on a vehicle provides for a three-phase alternating-direct converter comprising input terminals connected to an outside power grid, a high output terminal and a low output terminal, a direct-direct converter made up of two direct-direct converter circuits, a first converter circuit having a high input terminal connected to the high output terminal of the alternating-direct converter and a second converter circuit having a low input terminal connected to the low output terminal of the alternating-direct converter, the low input terminal of the first direct-direct converter circuit being connected to the high input terminal of the second direct-direct converter circuit, and the high output terminal of the first converter circuit being connected to the high output terminal of the second converter circuit and the low output terminal of the first converter circuit being connected to the low output terminal of the second converter circuit.