Motor Drive Battery Charging With Selective Voltage Conversion
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Solution Overview
Problem
Conventional motor driving system charging techniques do not efficiently determine the charging method based on the actual voltage of the vehicle battery, leading to efficiency deterioration, increased charging time, and reduced power due to switching losses.
Innovation Solution
A charging system and method that utilize an inverter, motor coils, and relays controlled by a controller to selectively choose between a first charging mode where power is directly applied to the battery and a second mode where power is applied to the motor's neutral point for voltage conversion, based on the battery's voltage and state of charge, to optimize charging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If voltage-boosting converter is used to convert 400V charging power to 800V for battery charging, then charging compatibility is improved, but device complexity, weight, volume, and cost increase
Solution Approach 1:
The motor driving system is designed to perform both its original motor driving function and an additional voltage conversion function for battery charging. The inverter and motor coils serve dual purposes: driving the motor during operation and acting as a voltage-boosting converter during charging, eliminating the need for a separate voltage-boosting converter and reducing overall system complexity
Solution Approach 2:
The voltage-boosting converter function is merged with the existing motor driving system components (inverter and motor coils). By combining these functions into a single integrated system, the patent avoids adding separate charging equipment and reduces the overall complexity, weight, and volume of the vehicle
2Device complexity
If motor driving system is used for voltage conversion during charging, then device complexity is reduced, but charging efficiency deteriorates due to switching losses
Solution Approach 1:
The system dynamically selects between two charging modes based on real-time battery voltage conditions: direct charging mode when battery voltage is below the charging power voltage, and voltage conversion mode when battery voltage exceeds the charging power voltage. This dynamic adaptation optimizes charging efficiency by avoiding unnecessary switching operations and minimizing energy losses
Solution Approach 2:
The charging process is segmented into two distinct modes: direct charging mode and voltage conversion mode. This segmentation allows the system to choose the most efficient charging method based on battery voltage conditions, thereby reducing overall energy loss during the charging process
3Adaptability or versatility
If voltage conversion mode is always used for charging, then charging flexibility is improved, but charging time increases due to conversion process
Solution Approach 1:
The system dynamically switches between direct charging mode and voltage conversion mode based on real-time battery voltage monitoring. When the battery voltage is below the charging power voltage, direct charging is applied for fast charging. When the battery voltage exceeds the charging power voltage, voltage conversion mode is activated. This dynamic switching optimizes charging time by avoiding unnecessary conversion steps
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
This approach reduces battery charging time and improves efficiency by directly applying charging power when the battery voltage is lower than the maximum voltage, and switches to voltage conversion when the battery voltage exceeds the maximum, thereby optimizing charging power usage.
Implementation Method 1
a technique of converting external charging power provided to a neutral point of a motor using an inverter and then providing the converted power to a battery to charge the battery
Data Source
AI summary
A charging system and method using a motor driving system which can charge a vehicle battery using charging equipment providing various voltages using a motor driving system provided in a vehicle and improve charging efficiency by selectively determining a charging mode in response to an actual voltage state of the vehicle battery.