Electric Vehicle Motor Control Device for Rapid Acceleration
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Solution Overview
Problem
Existing control methods for electric vehicle motors face challenges in accurately controlling the rotor phase during rapid acceleration or deceleration due to delays in control timing, which results in inaccurate motor control.
Innovation Solution
A control device for electric vehicles that corrects the rotor rotation angle using both the angular speed and differential of the electrical angle, ensuring precise control by accounting for the differential value of the angular speed, thereby eliminating delays during rapid acceleration or deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a rotation angle sensor with interrupt function is used to detect rotation angle and three-phase currents, then the motor can be controlled using detected values, but there is a deviation between the rotation angle at current detection time and the rotation angle at angle detection time, causing inaccurate motor control
Solution Approach 1:
The patent applies preliminary action by calculating and storing the differential value dω/dt in advance before it is needed for correction. The control device continuously monitors angular speed ω and pre-computes its differential, so that when correction is needed for rotation angle deviation, the value is already available. This eliminates the delay that would occur if the differential were calculated at the moment of correction, thereby maintaining both ease of operation and measurement precision.
2Device complexity
If the rotation angle detected at time t_B is used for control at time t_C, then the control process can be simplified, but the rotation angle does not reflect the actual rotor position at the command voltage application time, resulting in control inaccuracy
Solution Approach 1:
The patent implements feedback by continuously monitoring the angular speed ω and its differential dω/dt, then using this feedback information to correct the rotation angle Θ_B. The control device calculates the correction amount based on the pre-computed differential and the time interval (t_C - t_B), and applies this correction to obtain the accurate rotation angle Θ_C. This feedback mechanism ensures that the control system adapts to changes in rotor position without increasing overall system complexity, thereby maintaining both simplicity and reliability.
3Speed
If conventional control methods are used during rapid acceleration or deceleration, then the control timing delays occur, but the motor cannot be accurately controlled under dynamic conditions
Solution Approach 1:
The patent applies parameter changes by introducing the differential of angular speed dω/dt as a new parameter for correction purposes. Instead of relying solely on the static rotation angle Θ_B detected at time t_B, the system dynamically adjusts the rotation angle by incorporating the rate of change of angular speed. This parameter change allows the system to compensate for timing delays during rapid acceleration or deceleration, maintaining accurate rotor phase measurement even under dynamic conditions while preserving fast speed response.
Data Source
AI summary
A control device for an electric vehicle which is able to accurately control a traction motor of the electric vehicle without any delay in control timing during rapid acceleration or rapid deceleration of the motor, is provided. The control device for the electric vehicle includes an ECU and an inverter device including a motor control module. A rotation angle sensor configured to detect a rotation angle of a motor is provided, and the motor control module is provided with a rotation angle correction section configured to correct a rotation angle of a rotor of the motor which is used for vector control, by using an angular speed of an electrical angle which is the rotation angle detected by the rotation angle sensor and a differential value of the angular speed of the electrical angle.