Vehicle Electric Motor Coil Winding Number Adjustment
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Solution Overview
Problem
Existing vehicle electric motor systems cannot simultaneously satisfy the required performance in both high speed and low speed driving modes due to the inability to adjust coil winding numbers during operation, leading to reduced efficiency and unsatisfied torque specifications in each mode.
Innovation Solution
An electric motor system with an inverter and a controller that adjusts the coil winding number by serially connecting winding coils through a coil switching circuit, allowing for maximum winding number in low speed mode and minimum winding number in high speed mode, using a power switching circuit and coil switching circuit configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the coil winding number is increased to satisfy torque requirements in low speed driving mode, then the torque performance is improved, but the counter electromotive force becomes too high for the battery voltage in high speed driving mode
Solution Approach 1:
The patent applies the dynamics principle by making the coil winding configuration changeable during motor operation. The coil switching circuit dynamically reconfigures the series connection of winding coils based on detected driving mode, transitioning from maximum winding number in low speed mode to minimum winding number in high speed mode, allowing the system to adapt to different operational requirements in real-time
Solution Approach 2:
The patent implements parameter changes by modifying the effective winding number parameter according to driving conditions. The controller adjusts the coil winding number from a maximum value (when all coils are series-connected) to a minimum value (when only necessary coils are series-connected) based on the detected driving mode, thereby optimizing performance across different speed ranges
2Speed
If the coil winding number is reduced to satisfy battery voltage limits in high speed driving mode, then the high speed performance is improved, but the torque performance in low speed driving mode cannot be satisfied
Solution Approach 1:
The system dynamically switches between different winding configurations based on real-time driving mode detection. In high speed mode, the controller configures the coil switching circuit to use minimum winding number to reduce counter electromotive force and satisfy battery voltage limits, while in low speed mode it switches to maximum winding number to ensure sufficient torque generation
Solution Approach 2:
The effective winding number parameter is changed according to driving mode requirements. The controller reduces the winding number from maximum to minimum when transitioning from low speed to high speed mode, enabling the motor to operate within battery voltage constraints while maintaining optimal performance characteristics
3Force
If a fixed high winding number is used for low speed mode, then torque performance is improved, but efficiency is reduced in high speed mode due to weak field control current
Solution Approach 1:
The patent eliminates the efficiency loss in high speed mode by dynamically switching to a minimum winding number configuration when high speed driving is detected. This reduces the counter electromotive force and allows for more effective field control current utilization, thereby improving overall system efficiency during high speed operation
4Speed
If a fixed low winding number is used for high speed mode, then high speed performance is improved, but copper loss increases in low speed mode due to high winding current
Solution Approach 1:
The system dynamically switches to maximum winding number configuration when low speed driving mode is detected, which increases the counter electromotive force and reduces the required winding current. This significantly reduces copper loss (P=I²r) in low speed mode while maintaining the ability to operate in high speed mode with minimum winding number
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 solution enables the electric motor system to efficiently meet performance requirements in both driving modes by dynamically adjusting the coil winding number, improving efficiency and torque performance across different speed conditions.
Implementation Method 1
a counter electromotive force which is expressed as a multiplication of a magnetic flux of a coil wound around a stator of an electric motor and a rotating speed of a rotor of the electric motor increases in proportion to the rotating speed
Data Source
AI summary
Provided is an electric motor system for vehicles, which adjusts a coil winding number of a vehicle electric motor. The electric motor system for vehicles includes an inverter configured to include a power switching circuit connected to a vehicle battery in parallel and a coil switching circuit connected to the power switching circuit, wherein the coil switching circuit receives and outputs a driving current having different phases which is generated according to a switching operation of the power switching circuit, an electric motor configured to include a plurality of winding coils that receive the driving current and are wound at multi stages, and a controller configured to control a switching operation of the coil switching circuit to adjust a winding number of each of the plurality of winding coils to a maximum coil winding number by serially connecting all of the plurality of winding coils in a low speed driving mode and to adjust the winding number of each of the plurality of winding coils to a minimum coil winding number by serially connecting some of the plurality of winding coils in a high speed driving mode.