Battery Self-Heating Frequency Control to Prevent EV Vibration
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Solution Overview
Problem
The self-heating of batteries in electric vehicles causes motor jitter and subsequent vehicle vibration, leading to a poor driving experience and reduced motor lifespan, with the root cause of motor jitter remaining unidentified.
Innovation Solution
A method and apparatus that control the fundamental frequency of the self-heating current based on the real-time rotation speed of the first motor, staggering the fundamental frequency and rotation speed to prevent numerical relationships that cause motor jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If alternate pulse charging and discharging is performed between motor and battery to self-heat the battery, then heating efficiency is improved, but motor jitter and vehicle vibration occur
Solution Approach 1:
The patent dynamically adjusts the frequency of the self-heating current based on the real-time rotation speed of the motor. By making the heating frequency variable rather than fixed, the system avoids resonant conditions that cause vibration while maintaining heating effectiveness. The control unit continuously monitors motor speed and modifies the heating current frequency accordingly to stay away from problematic resonant frequencies.
Solution Approach 2:
The patent changes the frequency parameter of the self-heating current to resolve the vibration issue. By adjusting the frequency of the alternating current applied to the motor during self-heating, the system prevents resonance between the electrical excitation frequency and the mechanical rotation speed, thereby eliminating motor jitter and vehicle vibration while preserving the heating function.
2Temperature
If self-heating is performed using motor during traveling, then battery heating is achieved, but driving experience deteriorates due to vibration
Solution Approach 1:
The system dynamically adapts the heating current frequency to match real-time motor operating conditions. By continuously adjusting the frequency parameter based on actual motor speed, the system eliminates resonant vibrations that would otherwise be felt by passengers, thereby maintaining comfortable driving experience while achieving effective battery heating during travel.
Solution Approach 2:
The control unit receives feedback about the motor's real-time rotation speed and uses this information to adjust the self-heating current frequency. This closed-loop control ensures that the heating process does not create resonant conditions, preventing vibration and maintaining good driving experience while effectively heating the battery.
3Productivity
If self-heating current frequency aligns with motor rotation speed, then heating efficiency is maximized, but motor lifespan is reduced due to jitter
Solution Approach 1:
The system uses dynamic frequency adjustment to avoid fixed resonant frequencies that would cause motor jitter. By continuously adapting the heating current frequency to the motor's actual rotation speed, the system prevents harmful resonance while maintaining effective heating, thereby protecting motor lifespan without sacrificing heating efficiency.
Solution Approach 2:
The patent modifies the frequency parameter of the self-heating current to prevent alignment with motor rotation speed. By changing the frequency to avoid resonant conditions, the system eliminates motor jitter and protects motor lifespan while maintaining sufficient heating efficiency for battery thermal management.
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
The solution effectively eliminates motor jitter and vehicle vibration, improving the driving experience and extending the lifespan of the motor by ensuring the self-heating current frequency does not align with the motor's rotation speed.
Implementation Method 1
the battery pack needs to be heated, to cause a temperature of the battery pack to increase... the battery may be self-heated during traveling... self-heat the battery by using an internal resistor of the battery
Implementation Method 2
controlling a fundamental frequency of the self-heating current based on the real-time rotation speed, to stagger the fundamental frequency and the real-time rotation speed... effectively eliminates motor jitter and vehicle vibration
Data Source
AI summary
A method for inhibiting vehicle vibration during self-heating of a battery, the method is applicable to a vehicle including a power battery pack, a first motor, and a second motor. The method includes: controlling the power battery pack to output a drive current to the first motor to drive the first motor to rotate, where when the first motor rotates, the first motor drives the second motor to rotate; controlling the power battery pack to output a self-heating current to the second motor to self-heat a power battery; obtaining a real-time rotation speed of the first motor; and controlling a fundamental frequency of the self-heating current according to the real-time rotation speed, to stagger the fundamental frequency and the real-time rotation speed.