EV Motor System Voltage Conversion for Dual-Battery Charging
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Solution Overview
Problem
Electric vehicles face limitations in driving distance due to battery voltage issues, where voltage below the designed reference voltage restricts output power, and existing methods to increase voltage are limited by requiring strengthened motor system designs.
Innovation Solution
An electric vehicle system comprising a main battery, an auxiliary battery, and a motor system with a controller that adjusts external voltage to charge both batteries efficiently, using voltage stepping down or boosting through the motor system, regardless of external voltage levels during fast charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the voltage of the battery is increased to improve output power, then the available output power is improved, but the motor system requires strengthened withstand voltage design which increases device complexity
Solution Approach 1:
The battery system is divided into two separate battery modules (first battery module and second battery module) with different voltage levels. This segmentation allows each module to operate at its optimal voltage without requiring the entire motor system to be redesigned for higher voltage, thus improving output power while avoiding increased motor system complexity.
Solution Approach 2:
A converter is introduced as an intermediary device between the two battery modules with different voltages. The converter enables efficient power transmission and voltage matching between modules, allowing the system to utilize both high-voltage and low-voltage batteries effectively without directly increasing the motor system's withstand voltage requirements.
2Duration of action of moving object
If a single high-voltage battery is used to improve driving distance, then the voltage is improved, but the battery capacity and charge distribution become difficult to optimize
Solution Approach 1:
The battery system is divided into two separate battery modules (first battery module and second battery module) with different voltage levels. This segmentation allows each module to be optimized for specific capacity requirements while working together to extend overall driving distance, overcoming the limitations of a single battery design.
Solution Approach 2:
The system utilizes different voltage parameters for different battery modules (first voltage for the first module, second voltage for the second module). This parameter differentiation allows each module to be optimized for its specific voltage level, enabling better capacity utilization and extended driving distance without the compromises required by a single-voltage system.
3Productivity
If external voltage is applied to charge the battery, then the charging speed is improved, but the voltage level may not match the battery requirements during fast charging
Solution Approach 1:
The converter acts as an intermediary between the external charging voltage and the battery modules. It enables efficient power transmission and voltage matching, allowing fast charging to proceed at optimal speeds while the converter adapts the voltage levels to match the specific requirements of each battery module during the charging process.
Solution Approach 2:
The system changes voltage parameters dynamically based on which battery module is being charged. The controller selects whether to charge the first or second battery module based on external voltage levels, and the converter adjusts voltage levels accordingly, enabling fast charging adaptability to different voltage conditions.
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 effectively increases the driving distance of electric vehicles by efficiently charging both batteries using the motor system, regardless of external voltage levels, thereby enhancing power performance without requiring extensive motor system redesigns.
Implementation Method 1
the motor system is configured to step down and output a voltage of the main battery to the auxiliary battery
Implementation Method 2
the motor system is configured to boost and output a voltage of the auxiliary battery to the main battery
Data Source
AI summary
An electric vehicle includes a main battery and an auxiliary battery, a motor system including a motor and an inverter, and a controller which is configured to control an external voltage to be applied to the main battery or the auxiliary battery according to a level of the external voltage when a charging mode for charging the main battery and the auxiliary battery is performed, wherein the motor system is configured to step down and output a voltage of the main battery to the auxiliary battery when the external voltage is applied to the main battery, and is configured to boost and output a voltage of the auxiliary battery to the main battery when the external voltage is applied to the auxiliary battery.