Motor Current Phase Control for Torque Pulsation and Vehicle Vibration
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Solution Overview
Problem
Existing motor control devices cannot effectively reduce the influence of motor pulsation on vehicle vibration, as they do not account for the timing of vibration generation.
Innovation Solution
A motor control device with an inverter, current detection unit, and position detection unit that adjusts the current phase angle of the motor in response to vehicle vibration timing, making the waveform cycle of the alternating current irregular.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor is driven at a constant torque command value, then the motor produces the required driving torque, but torque pulsation occurs due to parameter irregularities causing vehicle vibration
Solution Approach 1:
The patent applies periodic action by changing the current phase angle periodically in response to vehicle vibration timing. The inverter control unit periodically adjusts the current phase angle to counteract the torque pulsation that causes vehicle vibration, thereby reducing the harmful vibrational effects while maintaining the required driving torque.
Solution Approach 2:
The patent employs parameter changes by modifying the current phase angle parameter in response to detected vehicle vibration timing. The inverter control unit changes the current phase angle to alter the motor's torque characteristics, reducing the torque pulsation amplitude and thereby decreasing vehicle vibration while preserving the overall driving torque output.
2Object-affected harmful factors
If the current phase angle is changed regardless of vibration timing, then the torque pulsation may be reduced, but the control cannot effectively reduce the influence on vehicle vibration
Solution Approach 1:
The patent implements feedback by using a vibration detection unit to detect vehicle vibration timing and feeding this information back to the inverter control unit. The control unit then adjusts the current phase angle in response to this feedback, ensuring that the phase angle change occurs at the appropriate timing to effectively reduce vehicle vibration influence.
Solution Approach 2:
The patent applies preliminary action by detecting vehicle vibration timing in advance and preparing the current phase angle adjustment accordingly. The inverter control unit changes the current phase angle in response to the detected vibration timing, proactively counteracting the torque pulsation before it fully manifests as harmful vehicle vibration.
3Object-affected harmful factors
If the current phase angle is changed in response to vibration timing, then the influence on vehicle vibration is reduced, but the control system complexity increases
Solution Approach 1:
The patent applies universality by integrating the vibration detection and current phase angle control functions within the existing inverter control unit. The inverter control unit performs both its standard motor control functions and the additional vibration reduction function by changing the current phase angle, thereby reducing control system complexity while still achieving effective vibration mitigation.
Data Source
AI summary
A motor control device includes: an inverter that supplies an alternating current to a motor mounted on a vehicle; a current detection unit that detects the alternating current; a position detection unit that detects a rotor phase angle of the motor; and an inverter control unit that controls the inverter based on a current value detected by the current detection unit and the rotor phase angle detected by the position detection unit, wherein the inverter control unit, in response to a timing at which vibration of the vehicle is generated, changes a current phase angle of the motor, and makes a cycle of a waveform of a resultant current of the alternating current irregular.