EV Motor Operating Point Control for Cold Battery Warming
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Solution Overview
Problem
Electric vehicle batteries experience degraded performance in low temperatures without auxiliary heat sources, which increase weight and cost.
Innovation Solution
Utilize the electric drive unit (motor and inverter) to generate additional heat by applying operating points that result in larger losses while maintaining requested torque, using the vehicle's existing components to warm the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat pumps or heaters are added to warm the battery, then the battery temperature is increased, but the weight and cost of the vehicle increase
Solution Approach 1:
The motor controller utilizes the motor's own operational characteristics to generate heat for warming the battery. By selecting operating points that produce larger losses, the system self-generates the necessary heat without requiring external heating components, thus avoiding additional weight while maintaining battery temperature within operational ranges
Solution Approach 2:
The invention converts the harmful effect of energy losses (heat generation during motor operation) into a beneficial effect by deliberately selecting operating points that produce larger losses to warm the battery. This transforms what is typically wasted energy into a useful heating source, eliminating the need for separate heating systems
2Temperature
If heat pumps or heaters are added to warm the battery, then the battery temperature is increased, but the device complexity and cost increase
Solution Approach 1:
The motor controller is designed to perform multiple functions: it not only controls the motor for propulsion but also selectively operates the motor at specific operating points to generate heat for battery warming. This multi-functionality eliminates the need for separate heating devices, reducing overall system complexity and cost
Solution Approach 2:
The existing motor controller and motor system serve the additional function of battery heating through intelligent operating point selection, eliminating the need for separate heating components and reducing system complexity
3Temperature
If the motor operates at operating points with larger losses, then heat is generated to warm the battery, but the energy efficiency of the motor decreases
Solution Approach 1:
The motor operates at selected operating points that produce larger losses than the minimum required for propulsion. This partial or excessive action is deliberately applied only when battery warming is needed, rather than continuously, thus generating sufficient heat while minimizing the impact on overall energy efficiency
Solution Approach 2:
The motor controller periodically selects operating points with larger losses when battery temperature requires warming, rather than maintaining such operation continuously. This periodic application of excessive action generates necessary heat while preserving energy efficiency during normal operation
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
Efficiently warms the battery without additional parts, reducing weight and cost while maintaining traction performance.
Implementation Method 1
An operating point for a vehicle electric motor is selected to produce requested torque inefficiently, to generate additional heat to warm the battery
Data Source
AI summary
An operating point for a vehicle electric motor is selected to produce requested torque inefficiently, to generate additional heat to warm the battery. A torque command for operation of the vehicle at a desired speed and a heat power command for an amount of heat needed to warm a battery powering the vehicle electric motor are received by a motor controller. The motor controller determines an operating point of the vehicle electric motor that corresponds to both the requested torque and the amount of heat, and the vehicle electric motor is controlled based on the determined operating point.