EV Charging Apparatus Merging OBC With Inverter
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Solution Overview
Problem
Existing charging apparatuses for electric vehicles are bulky and costly due to the need for increased on-board charger (OBC) capacity to handle high-capacity batteries, which also results in longer charging times and increased size, and they struggle to adapt to various types of AC power sources.
Innovation Solution
A charging apparatus with a simplified structure that includes a motor, inverter, power factor corrector, switch network, and controller, capable of receiving single-phase and multi-phase AC power, and performing current mode duty control to reduce leakage current and convert power factor corrector into different types of converters, allowing it to handle various AC input conditions without the need for insulation measures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the OBC capacity is increased to charge large-capacity batteries faster, then the charging time is reduced, but the size and production cost of the electric vehicle increase
Solution Approach 1:
The patent combines the OBC functions with the inverter and motor controller into a single integrated power conversion system. The inverter performs both motor control functions and battery charging functions, eliminating the need for a separate OBC hardware unit. This merging of functions allows the system to handle large-capacity battery charging without increasing overall vehicle size.
Solution Approach 2:
The inverter is designed to perform multiple functions: it serves as both the motor controller for driving the electric motor and as the OBC for charging the battery. The power conversion circuit can operate in different modes (motoring mode and regenerative braking/charging mode) depending on the operational requirements, providing universal functionality without requiring dedicated separate systems.
2Productivity
If the OBC capacity is increased to charge large-capacity batteries faster, then the charging time is reduced, but the production cost of the electric vehicle increases
Solution Approach 1:
By merging the OBC functionality into the existing inverter system, the patent eliminates the need for separate OBC hardware components. This reduces the total bill of materials and manufacturing complexity, thereby lowering production costs while maintaining the capability to charge large-capacity batteries efficiently.
Solution Approach 2:
The multi-functional inverter design allows a single device to perform both motor control and battery charging operations. This universality reduces the overall component count and system complexity, leading to lower manufacturing costs compared to having separate dedicated OBC and motor controller units.
3Adaptability or versatility
If a separate OBC is added to handle various AC power types, then the adaptability to different power sources is improved, but the device complexity increases
Solution Approach 1:
The inverter is designed with universal power conversion capability that can handle various AC power input types (single-phase and three-phase) and convert them appropriately for battery charging. The control system automatically detects and adapts to different input configurations, providing power source compatibility without requiring multiple dedicated circuits or complex switching mechanisms.
Solution Approach 2:
The system employs dynamic control strategies that allow the inverter to adapt its operating parameters based on the detected AC power input type. The controller dynamically adjusts the power conversion process to optimize performance for different input conditions, maintaining simplicity while achieving versatility through intelligent control rather than hardware complexity.
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 reduces the size and cost of the charging apparatus while efficiently charging high-capacity batteries across different AC power types, minimizing leakage current and meeting safety standards.
Implementation Method 1
a power factor corrector having a single three-leg half bridge circuit configured to receive the AC input power through the AC power input terminal
Implementation Method 2
a link capacitor configured to be charged through at least one of combinations of the power factor corrector, the motor, and the inverter
Implementation Method 3
a switch network having at least one switch for selectively connecting the AC power input terminal to the power factor corrector, the link capacitor, the motor, or the inverter
Implementation Method 4
The controller is configured to perform the current mode duty control to reduce the leakage current in the switching control of the power factor corrector
Data Source
AI summary
A charging apparatus for an electric vehicle is provided. The apparatus charges a vehicle battery upon receiving power from different power sources. The apparatus includes a motor generating power to drive the electric vehicle and an inverter supplying power to the motor. An AC power input terminal receives at least one of single-phase AC power and multi-phase AC power. A power factor corrector having a single three-leg half bridge circuit receives the AC input power through the AC power input terminal. A link capacitor is charged through a combination of the power factor corrector, the motor, and the inverter. A switch network has at least one switch for selectively connecting the AC power input terminal to the power factor corrector, the link capacitor, the motor, or the inverter. A controller operates the power factor corrector, the switch network, and the inverter based on a condition of received AC input power.