Hybrid Vehicle Controller Power Management During Mode Switching
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Solution Overview
Problem
Hybrid vehicles face a temporary reduction in driving force when switching from EV mode to parallel mode due to power limitations imposed on the boost converter to prevent overheating, leading to acceleration failures and poor drivability.
Innovation Solution
A controller that calculates the maximum electric power available to the drive motor by subtracting the starter device's consumption from the limited power during boost converter power limitations, activating the starter device only when the required power reaches this calculated maximum, ensuring consistent power supply to the drive motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power limitation is imposed on the boost converter to prevent overheating, then the reliability of the boost converter is improved, but the driving force of the drive wheel is temporarily reduced when switching from EV mode to parallel mode
Solution Approach 1:
The control unit calculates the maximum electric power available to the drive motor by subtracting the starter device's power consumption from the boost converter's limited power in advance. This preliminary calculation allows the system to determine the optimal timing for mode switching before the actual transition occurs, ensuring that the drive motor receives sufficient power during the critical switching period.
Solution Approach 2:
The control unit continuously monitors the required power of the drive motor and compares it with the calculated maximum electric power. When the required power reaches the calculated maximum, the control unit triggers the mode switching from EV mode to parallel mode. This feedback mechanism ensures that mode switching occurs at the precise moment when it can maintain driving force while respecting the boost converter's power limitations.
2Adaptability or versatility
If the starter device is activated to start the engine during mode switching, then the parallel mode operation is achieved, but the power supply to the drive motor is reduced by the starter device's power consumption
Solution Approach 1:
The control unit performs preliminary calculation of the maximum electric power available to the drive motor by subtracting the starter device's power consumption from the boost converter's limited power. This advance calculation allows the system to plan the power distribution before the starter device is activated, ensuring that the drive motor receives adequate power throughout the mode switching process.
Solution Approach 2:
The control unit acts as an intermediary that coordinates between the starter device activation and the drive motor power supply. By calculating the maximum electric power in advance and using this information to time the mode switching, the control unit mediates the conflict between starter device operation and drive motor power requirements, ensuring both functions can operate effectively.
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 solution maintains the required power level to the drive motor, preventing temporary reductions in driving force and ensuring satisfactory drivability by optimizing the timing of mode switching and adjusting for temperature and battery state.
Implementation Method 1
a voltage transformer (boost converter) that steps up electric power of a drive battery
Data Source
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AI summary
A controller of a hybrid vehicle includes: a control unit (27) configured to activate a starter device (11) for starting any one of a drive motor (2) and an engine (3) by stepping up electric power from a battery (20) by a voltage transformer (18). The control unit (27) includes a limitation part that limits passing power of the voltage transformer (18) when the temperature of the voltage transformer (18) rises, and a calculation part that obtains a maximum electric power that can be supplied to the drive motor (2) when the starter device is activated, by subtracting a consumed power of the starter device from limited power during limitation of passing power by the limitation part. The control unit (27) activates the starter device (11) and starts the engine (3), when required power of the drive motor (2) reaches the maximum electric power calculated by the calculation part during limitation of passing power by the limitation part.