Battery Heating Inverter Control for Balanced Switch Wear
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Solution Overview
Problem
Existing power battery heating methods lead to uneven service life of power switching devices in vehicles due to unbalanced on/off operations, causing differential wear and tear on upper and lower legs of the same phase.
Innovation Solution
A method and apparatus that control a three-phase inverter to heat a power battery by adjusting the phase current of a three-phase alternating current motor, where the direct-axis current direction changes periodically, ensuring equal switching times for both upper and lower legs, thereby balancing the service life of power switching devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the motor is controlled to output zero torque with unchanged direct-axis current direction, then the power battery can be heated, but the upper leg and lower leg of power switching devices have different service lives
Solution Approach 1:
The patent applies periodic action by making the direct-axis current direction change periodically between positive and negative directions during motor heating operation. This periodic reversal ensures that both upper and lower legs of power switching devices in the same phase undergo equal numbers of on/off actions over complete cycles, balancing their service life and wear characteristics while maintaining continuous heating capability.
2Reliability
If the direct-axis current direction is changed periodically, then the service life of power switching devices is balanced, but the control complexity increases
Solution Approach 1:
The patent implements parameter changes by dynamically adjusting the direct-axis current direction as a controllable parameter. The control system periodically switches the direct-axis current between positive and negative directions according to a predetermined pattern, while maintaining the quadrature-axis current to ensure heating power requirements are met. This parameter modulation achieves balanced switching device service life through relatively simple control logic.
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 balances the service life of power switching devices by ensuring equal switching times for both legs, reducing wear and tear and improving the reliability of the heating process.
Implementation Method 1
the three-phase alternating current motor generates heat according to heating energy provided by a heating energy source, to heat a coolant flowing through the power battery
Data Source
AI summary
In a power battery heating method for a vehicle, when a current temperature value of a power battery is lower than a preset temperature value, and a heating condition of the power battery meets a preset condition, a three-phase inverter is controlled to cause a three-phase alternating current motor to generate heat according to heating energy, to heat a coolant flowing through the power battery, a preset quadrature-axis current that causes a torque value outputted by the motor to be an appropriate value is obtained, and a corresponding preset direct-axis current is obtained according to heating power of the power battery, so as to control, according to the preset direct-axis current and the preset quadrature-axis current, the three-phase inverter to adjust a phase current of the three-phase alternating current motor in the heating process, where a direction of the preset direct-axis current changes periodically in the heating process.