Motor Driving System for High-Voltage Battery Charging
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Solution Overview
Problem
The existing battery charging systems for electric vehicles require a bulky and expensive boost converter to increase the charging voltage from 400V to 800V or higher, which is costly and difficult to integrate into vehicles, especially when using a motor driving system with open end winding mode.
Innovation Solution
A vehicle battery charging system that uses a motor driving system with multiple inverters and transfer switches to convert and boost the charging voltage without an additional dedicated device, by controlling the switching elements and pulse width modulation to supply the boosted voltage directly to the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a boost converter is added to increase charging voltage from 400V to 800V, then the charging voltage matches the battery voltage standard, but the system becomes heavy, bulky, and expensive
Solution Approach 1:
The motor driving system's inverter is designed to perform dual functions: motor control during normal operation and voltage boosting during charging. By configuring the inverter switches in specific patterns, the same hardware can convert 400V charging input to 800V battery charging output, eliminating the need for a separate boost converter and reducing overall system weight and cost
Solution Approach 2:
The patent combines the boost converter functionality with the existing inverter circuitry of the motor driving system. The inverter's switching elements are controlled to create a boost converter topology during charging mode, merging two previously separate functions into a single integrated system, thereby removing the need for additional heavy and expensive boosting equipment
2Adaptability or versatility
If a boost converter with large capacity is installed to handle wide voltage range, then voltage boosting capability is achieved, but the device complexity and cost increase
Solution Approach 1:
The inverter is designed to operate in multiple modes: motor control mode during normal driving and voltage boosting mode during charging. The same switching elements and control circuitry adapt their operation based on the required function, providing wide voltage adaptability without requiring separate dedicated circuits for each function
Solution Approach 2:
The system dynamically reconfigures the inverter switch states depending on the operating mode. During charging, the switches are controlled to create a boost converter topology; during motor operation, they create an inverter topology. This dynamic reconfiguration allows a single system to handle multiple voltage requirements without fixed, complex hardware for each scenario
3Power
If a separate boost converter is provided for charging, then the charging system can handle high voltage batteries, but additional cost and infrastructure are required
Solution Approach 1:
The motor driving system's inverter is designed to serve dual purposes: driving the motor during normal operation and boosting voltage during battery charging. This multi-functionality eliminates the need for separate charging equipment, reducing manufacturing costs and making high-voltage battery charging accessible without additional expensive infrastructure
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
Enables efficient battery charging without the need for additional infrastructure or boost circuits, reducing costs and allowing for various external charging voltages, while maintaining high-efficiency open end winding motor operation.
Implementation Method 1
controlling pulse width modulation of a lower switching element of the first inverter
Data Source
AI summary
A system for charging a vehicle battery using a motor driving system includes a first inverter including a plurality of first switching elements; a second inverter including a plurality of second switching elements; a plurality of transfer switches having first ends and second ends, the first ends thereof being respectively connected to the second ends of a plurality of windings, and the second ends thereof being connected to each other; and a controller configured, in a charging mode, to control opened/shorted states of the switching elements included in the first inverter and the second inverter and the plurality of transfer switches, so that a DC charging voltage applied to a portion between of the second ends of the plurality of transfer switches and a negative terminal of the battery is supplied to the battery.