Battery Warming Circuit Using Inverter Switching Elements
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Solution Overview
Problem
Existing battery warming systems for vehicles require regenerative braking or engine driving to maintain secondary battery temperature, limiting flexibility and efficiency.
Innovation Solution
A battery warming circuit using an inverter circuit and a 3-phase alternating current motor, where switching elements control charge-discharge currents to generate Joule heat, warming the secondary battery without engine or motor operation, utilizing an accumulation unit to store back electromotive force and supply it back to the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If regenerative braking or engine driving is used to warm the secondary battery, then the battery temperature is maintained, but the system requires external power sources and reduces operational flexibility
Solution Approach 1:
The system uses the inverter circuit's own switching elements and the motor's phase coil to generate heat for warming the secondary battery, eliminating the need for external power sources like engine driving or regenerative braking. The inverter circuit serves itself by utilizing its existing components for the additional function of battery warming.
2Temperature
If regenerative braking or engine driving is used to charge the secondary battery, then the battery temperature is raised, but additional system operations are required
Solution Approach 1:
The inverter circuit is designed to perform multiple functions: it can convert DC to AC power for motor operation, and simultaneously serve as a battery warming device by controlling the switching elements to generate heat through the motor's phase coil. This multi-functionality eliminates the need for separate battery warming systems.
3Productivity
If the inverter circuit switches at high frequency for power conversion, then efficient power conversion is achieved, but significant heat is generated that requires management
Solution Approach 1:
The heat that would normally be considered waste heat from high-frequency switching is converted into a useful resource for warming the secondary battery. By controlling the switching elements to operate in a specific mode, the system generates heat through the motor's phase coil that is directed to warm the battery, transforming a potential problem into a beneficial function.
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
Effectively raises the secondary battery temperature using internal resistance-generated Joule heat, enhancing efficiency and reliability without relying on external heating or engine operation, and can be activated based on temperature, occupancy, or environmental conditions.
Implementation Method 1
accumulates back electromotive force generated in the specific coil by switching the second switching element on and off
Implementation Method 2
uses internal resistance of the secondary battery to generate Joule heat, thereby raising the temperature of the secondary battery
Data Source
AI summary
A battery warming circuit is a circuit installed in a vehicle provided with an inverter circuit, which is supplied with direct current electrical power from a secondary battery, and a 3-phase alternating current motor, and this circuit includes: a switch control unit, which has first and second terminals connected to control terminals of first and second switching elements, and controls turning the first and second switching elements on and off; an accumulation unit which has a third terminal connected to the other end of a specific coil, and accumulates back electromotive force generated in the specific coil by turning the second switching element on and off, with the first switching element being turned on; and a charging control unit which is provided between the positive electrode of the secondary battery and the accumulation unit, and supplies electrical power accumulated in the accumulation unit to the secondary battery.