Battery Resonance Heating via Inverter Ripple Frequency Control
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Solution Overview
Problem
Existing battery temperature raising methods using current ripple generation increase loudness due to sound pressure in multiple frequency ranges, which is undesirable.
Innovation Solution
Control the ripple frequency of the inverter output current to match the resonance frequency of the battery circuit, increasing the amplitude of the current ripple through resonance to efficiently heat the battery while minimizing loudness by confining sound pressure to the resonance frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the ripple frequency of the output current from the inverter is controlled to the resonance frequency of the battery circuit to efficiently heat the battery, then the amplitude of current ripple increases due to resonance, but the sound pressure level increases in two frequency ranges (switching frequency and resonance frequency), which increases loudness
Solution Approach 1:
The patent changes the switching frequency parameter of the inverter to match the resonance frequency of the battery circuit. This parameter change causes the ripple frequency to align with the resonance frequency, amplifying the current ripple amplitude through resonance to efficiently heat the battery, while consolidating the sound pressure increase to a single frequency range rather than two, thereby reducing overall loudness
Solution Approach 2:
The patent utilizes electrical resonance (analogous to mechanical vibration) by setting the switching frequency to match the battery circuit's resonance frequency. This creates resonant oscillations in the current ripple, amplifying the heating effect while concentrating the acoustic energy at a single frequency, thus improving heating efficiency and reducing perceived loudness
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
Efficiently raises battery temperature while reducing loudness by aligning the switching frequency with the resonance frequency, thereby enhancing heating efficiency and minimizing noise.
Implementation Method 1
an inverter connected between the battery and the electrical machine and configured to be driven at a predetermined switching frequency and to convert direct current power stored in the battery to alternating current power to supply the alternating current power to the electrical machine
Implementation Method 2
the amplitude of the current ripple increases due to resonance, so that the battery can be efficiently raised in temperature (heated)
Data Source
AI summary
The DC power of the battery is converted into AC power by an inverter to drive a motor generator (MG). The control ECU executes the temperature raising control at the time of low temperature of the battery. During the temperature raising control, the control ECU sets the carrier frequency of the inverter to the resonance frequency of the battery circuit including the battery. The frequency of the switching ripple current coincides with the resonance frequency, and the amplitude of the current ripple increases, so that the battery can be efficiently raised in temperature (heated). The sound pressure level increases only in the region of the resonance frequency, and an increase in loudness can be reduced.