Rotor Temperature Estimation for EV Battery Self-Heating Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for heating traction batteries in electric vehicles, particularly those using permanent magnet motors, struggle to accurately estimate rotor temperature during static or locked-rotor conditions, leading to inefficiencies in self-heating duration and potential demagnetization of permanent magnets.
Innovation Solution
A method that acquires and estimates rotor temperature using system parameters such as specific heat capacity, mass, and heating power, and stops self-heating when the rotor reaches demagnetization temperature, incorporating formulas to calculate temperature changes and heating powers for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing rotor temperature estimation methods are used under normal operating conditions, then temperature estimation is accurate during motor operation, but the methods become inapplicable under static or locked-rotor conditions, leading to inaccurate self-heating duration estimation
Solution Approach 1:
The patent changes the estimation parameters from normal operating parameters (current, speed, torque) to parameters suitable for static conditions (heating power, specific heat capacity, mass, time). This allows the temperature estimation to be valid under both normal operation and static/locked-rotor conditions by adapting the physical model to the operating state.
2Temperature
If self-heating duration is extended to ensure battery heating, then battery temperature increases, but rotor temperature may reach demagnetization temperature, causing permanent magnet damage
Solution Approach 1:
The patent implements a feedback control mechanism where the estimated rotor temperature is continuously monitored and used to adjust the self-heating duration. When the estimated rotor temperature approaches the demagnetization temperature, the heating is stopped or reduced, preventing permanent magnet damage while still achieving battery heating objectives.
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 allows for accurate estimation and control of rotor temperature, preventing demagnetization and ensuring efficient self-heating of traction batteries, even in static or locked-rotor conditions, thereby enhancing the reliability and performance of electric vehicle systems.
Implementation Method 1
the self-heating technology adjusts the pulse current waveform that can heat the battery pack on the power architecture of the electric vehicle
Implementation Method 2
establishing a heat generation model to obtain the amount of heat generated; establishing a heat dissipation model to obtain the amount of heat dissipated
Implementation Method 3
establishing a heat dissipation model to obtain the amount of heat dissipated
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Disclosed is a traction battery self-heating control method and a device. Acquiring a second temperature of a rotor at a current sampling time according to system parameters and a first temperature of the rotor at a previous sampling time (S201), and estimating a third temperature of the rotor at a next sampling time according to the first temperature and the second temperature (S202), and stopping the self-heating of the traction battery when the third temperature reaches a demagnetization temperature of the rotor (S204). Whether to stop the self-heating of the traction battery is determined by estimating a rotor temperature under the self-heating condition, and comparing the rotor temperature with the demagnetization temperature of the rotor, and thus the self-heating control of the traction battery is realized.