EV Motor Angle Feedback Control for Stop-State Vibration
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Solution Overview
Problem
Electrified vehicles experience vibration when the motor is energized while the vehicle is stopped, due to torque fluctuations around a specific electrical angle where no torque is generated.
Innovation Solution
A control device is implemented to control the energization current of the motor based on the generated torque, feedback torque for vibration suppression, and rated current, allowing the electrical angle to be adjusted close to the target angle where torque is zero, thereby reducing torque fluctuations and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor is energized while the electrified vehicle is stopped, then the motor can provide torque, but torque fluctuations occur causing vibration
Solution Approach 1:
The control device calculates feedback torque based on the deviation between the current electrical angle and the target electrical angle, then adjusts the energization current accordingly. This closed-loop feedback mechanism suppresses torque fluctuations by continuously correcting the electrical angle, thereby reducing vibration while maintaining motor torque output.
Solution Approach 2:
The control device dynamically adjusts the electrical angle parameter to maintain it near the target angle where torque fluctuation is minimized. By changing the electrical angle parameter in real-time based on feedback, the system reduces vibration while preserving the motor's torque-generating capability.
2Object-affected harmful factors
If the electrical angle is adjusted to suppress vibration, then torque fluctuations are reduced, but control complexity increases
Solution Approach 1:
The control device implements a feedback control mechanism that calculates the deviation between the current electrical angle and the target electrical angle, then determines feedback torque to correct this deviation. This systematic approach manages control complexity by providing a clear feedback loop with defined calculation steps.
Solution Approach 2:
The control device pre-calculates the target electrical angle based on the initial electrical angle before adjusting the energization current. This preliminary action simplifies the control process by establishing a reference point in advance, reducing the complexity of real-time adjustments.
3Object-affected harmful factors
If feedback torque is calculated based on electrical angle deviation, then vibration suppression is achieved, but calculation complexity increases
Solution Approach 1:
The control device calculates feedback torque using the formula: feedback torque = gain × (target electrical angle - current electrical angle). This straightforward feedback calculation achieves vibration suppression while keeping the computational complexity manageable through a simple linear relationship.
4Object-affected harmful factors
If the energization current is controlled based on generated torque and feedback torque, then vibration is suppressed, but control precision requirements increase
Solution Approach 1:
The control device continuously monitors the electrical angle and calculates feedback torque based on the deviation from the target angle. This feedback mechanism compensates for precision errors by dynamically adjusting the energization current, thereby suppressing vibration while managing the requirements for control precision.
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
The solution effectively suppresses vibrations in stationary electrified vehicles by reducing torque fluctuations, allowing for smoother operations during charging or other stationary conditions.
Implementation Method 1
an inverter provided between the battery and the motor to convert direct-current power from the battery to alternating-current power to be supplied to the motor
Implementation Method 2
When the motor is energized, generated torque corresponding to the electrical angle of the motor is generated
Data Source
AI summary
Electrified vehicle includes a motor, a battery, an inverter, and a control device. The inverter is provided between the battery and the motor, and converts DC power from the battery into AC power. AC power is supplied to the motor. The control device can execute a specified operation while electrified vehicle is stopped. The specific operation includes determining a target electrical angle based on an initial value of the electrical angle of the motor, controlling the operation of the inverter to start energizing the motor with a predetermined rated current, identifying generated torque in the motor based on the rated current and the current value of the electrical angle, determining feedback torque for damping based on a deviation of the current value with respect to the target electrical angle, and controlling an energizing current to the motor based on the generated torque, the feedback torque, and the rated current.