Electric Vehicle Drive Torque Control for Torsional Vibration
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Solution Overview
Problem
Existing electric motor vehicle control systems result in a power difference between the power supplied to the drive motor and the power consumed, leading to unintended charging of the storage battery, which is not fully utilized as drive power due to torsional vibration issues in the drive system.
Innovation Solution
The system employs a damping filter to remove or reduce the frequency component equivalent to torsional vibration in the power generation and drive torque calculations, ensuring that the power generated is completely consumed at the drive motor without exceeding or falling short of the generated power, thereby matching generated and drive power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the requested drive torque is filtered to remove torsional vibration frequency components for smooth vehicle operation, then the drive motor torque can be controlled to match the target drive torque smoothly, but a power difference arises between the power supplied to the drive motor and the power consumed, causing unintended charging or discharging of the storage battery
Solution Approach 1:
The control device calculates a target power generation amount based on the difference between the power supplied to the drive motor and the power consumed by the drive motor, then controls the power supply source to generate this target power. This feedback mechanism ensures that the power generated matches the actual power needs, eliminating the power difference that causes unintended battery charging or discharging while maintaining smooth vehicle operation.
Solution Approach 2:
The system uses the power difference information itself to determine the target power generation amount, allowing the system to self-regulate and balance power supply and consumption without external intervention, thereby preventing energy loss and maintaining operational stability simultaneously.
2Loss of energy
If the power supplied to the drive motor matches the power consumed exactly, then no unintended battery charging occurs, but it becomes difficult to suppress torsional vibration in the drive system
Solution Approach 1:
The control approach separates the power control into two independent parts: (1) controlling the drive motor torque based on filtered requested drive torque to suppress torsional vibration, and (2) controlling the power supply source to generate power matching the difference between supplied and consumed power. This segmentation allows both smooth operation and efficient power utilization to be achieved simultaneously without interference.
Data Source
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AI summary
A vehicle comprises a drive motor (15) that generates a drive torque to be transmitted to drive wheels (18), a power supply source (12, 17) that includes, at least, a generator (12), and supplies power to the drive motor (15), and a programmable controller (20). The programmable controller (20) is programmed so as to calculate a required drive torque based upon ave hicle traveling state, calculate a power supply value representing power to be supplied from the power supply source (12, 17) to the drive motor (15) based upon the required drive torque, control the drive motor (15) to enable the drive motor (15) to output a drive torque determined by reducing a frequency component in the required drive torque, which is equivalent to torsional vibration of the drive system, and control the power supply source (12, 17) to enable the power supply source (12, 17) to supply to the drive motor (15) power obtained by reducing the frequency component in the power supply that is equivalent to the torsional vibration of the drive system.