Asynchronous Motor Heating for Low-Temperature Battery Preheating
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Solution Overview
Problem
The use of additional heating apparatuses, such as PTCs, to heat battery packs in low-temperature environments increases system costs and inefficiencies in heating the coolant for asynchronous motors, particularly in new energy vehicles.
Innovation Solution
Injecting a current into the stator winding of an asynchronous motor to generate heat without generating torque, using a direct or harmonic current to heat the battery pack through a heat exchanger, optimizing heat generation by utilizing both copper and iron losses in the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an additional PTC heating apparatus is used to heat the battery pack, then the battery pack can be heated in low-temperature environments, but the system cost increases
Solution Approach 1:
The asynchronous motor is made to serve dual purposes: driving the vehicle and heating the battery pack/coolant. By injecting specific current patterns (direct current or harmonic currents) into the motor windings, the motor generates heat through copper losses and iron losses without producing torque, thereby functioning as both a drive motor and a heating device simultaneously
Solution Approach 2:
The system uses its own motor to heat the battery pack and coolant rather than relying on external heating apparatus. The motor's inherent electrical losses are harnessed to heat the coolant, which then circulates through the battery pack to maintain optimal temperature, making the system self-sufficient for thermal management
2Temperature
If conventional PTC heating is used, then the battery pack can be preheated, but the heating rate of the coolant is insufficient
Solution Approach 1:
The invention changes the electrical parameters injected into the motor windings to optimize heat generation. By using direct current or specific harmonic current patterns, the motor generates maximum heat through resistive losses and magnetic hysteresis without producing mechanical torque, thereby significantly increasing the heating rate of the coolant compared to conventional PTC heating
3Temperature
If additional heating apparatus is installed, then heating capability is provided, but the system structure becomes more complex
Solution Approach 1:
The asynchronous motor performs multiple functions: vehicle propulsion, coolant heating, and battery pack heating. The same motor windings that produce torque during normal operation are used to generate heat when specific current patterns are applied, eliminating the need for separate heating elements and simplifying the overall system structure
Solution Approach 2:
The heating function is merged with the motor function. The motor's electrical losses, which are normally wasted energy, are redirected to heat the coolant that circulates through both the motor housing and the battery pack, combining the drive system and thermal management system into a unified structure
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 method reduces system costs by eliminating the need for additional heating apparatuses and enhances the heating rate of the coolant, effectively preheating the battery pack regardless of the motor's stationary or running state.
Implementation Method 1
injecting a first current into a stator winding of the asynchronous motor, where the first current is for generating heat
Implementation Method 2
the first current is a direct current or a harmonic current that generates pulsating magnetomotive force
Data Source
AI summary
A method for processing an asynchronous motor includes obtaining indication trigger information; and injecting, in response to the indication trigger information, a first current into a stator winding of the asynchronous motor, where the first current is for generating heat without a torque for the asynchronous motor, and the heat heats a battery pack through a heat exchanger.