EV Battery Warm-Up via Intermittent Boost Converter Control
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Solution Overview
Problem
Conventional battery warm-up methods in electric vehicles increase noise during steady traveling due to current ripple, which affects driver comfort.
Innovation Solution
An electric vehicle system that includes a boost converter, inverter, motor generator, temperature sensor, current sensor, voltage sensor, and a control section with intermittent boosting operation and threshold switching mechanisms to manage battery warm-up without increasing noise, by stopping and restarting the boost converter based on battery current and voltage thresholds, and adjusting these thresholds according to temperature and vehicle speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the switching frequency of the boost converter is reduced to increase ripple current for battery warm-up, then the battery warming effectiveness is improved, but the noise in the electric circuit increases
Solution Approach 1:
The patent implements periodic action by intermittently stopping and restarting the boost converter based on battery current and voltage thresholds. Instead of continuously operating at reduced switching frequency (which causes noise), the system periodically activates the boost converter only when necessary to generate ripple current for battery warm-up, thereby achieving warming effectiveness while suppressing noise during steady traveling
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the operation thresholds of the boost converter based on battery temperature conditions. When battery temperature is low, the threshold switching means switches to wider threshold ranges (third threshold range for current, fourth threshold range for voltage), enabling the intermittent boosting operation to occur more frequently and effectively warm the battery without causing excessive noise
2Temperature
If the boost converter operates continuously to maintain voltage, then the voltage stability is improved, but the battery cannot be effectively warmed up
Solution Approach 1:
The patent implements feedback control by continuously monitoring battery current and boosted voltage through current sensor and voltage sensor, and comparing these values against threshold ranges. The control section uses this feedback to intelligently determine when to stop or restart the boost converter, ensuring that voltage stability is maintained while creating opportunities for ripple current generation to warm the battery
Solution Approach 2:
The system employs periodic action by intermittently stopping the boost converter based on feedback from sensors. This periodic interruption creates ripple current for battery warm-up while the control section ensures that the boost converter restarts promptly when voltage or current thresholds are exceeded, thus maintaining overall voltage stability
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 warms the battery while minimizing noise during steady traveling by optimizing the boost converter's operation, ensuring efficient battery warm-up without the noise associated with current ripple.
Implementation Method 1
a method of boosting a low DC voltage of the battery into a high DC voltage using a boost converter
Implementation Method 2
supplying the high DC voltage to inverters that transmit and receive power to and from the electric motor and the generator, respectively, with the inverters converting the DC power into three-phase AC power for driving of the electric motor
Implementation Method 3
converting three-phase AC power generated by the generator into DC power to charge the battery
Implementation Method 4
A hybrid vehicle includes an engine, an electric motor, and a generator... a method of boosting a low DC voltage of the battery into a high DC voltage
Data Source
AI summary
A hybrid vehicle includes a battery, a boost converter, a battery temperature sensor, a battery current sensor, a high-voltage sensor, and a control section. The control section includes an intermittent boosting operation program which stops the boost converter when a temperature of the battery is equal to or higher than a predetermined temperature and when an absolute value of a battery current is within a range of ±I0 and which restarts the boost converter when an actual boosted voltage is outside a range from VH2 to VH4, and a threshold switching program that switches the threshold range to ±I2 that is wider than the range of ±I0 and switches the range from the threshold VH2 to the threshold VH4 to a wider range from a threshold VH3 to a threshold VH5 when the battery temperature is lower than the predetermined temperature.