Motor Speed Learning Control for Smooth EV Gear Shifts
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Solution Overview
Problem
Existing electrified vehicle technologies face challenges in reducing shift shock during gear changes when the appropriate rotational speed is unknown, particularly in vehicles converted from gasoline vehicles, where the original vehicle's structure affects the required rotational speed.
Innovation Solution
Incorporating a rotational speed sensor and a control circuit that performs a learning process to detect changes in motor rotational speed during shift changes, allowing the control circuit to adjust the motor's rotational speed accordingly, thereby reducing shift shock without relying on pre-set target speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed target rotational speed is set in the control circuit, then shift shock can be reduced in vehicles with known characteristics, but the system cannot adapt to vehicles with varying drive system characteristics (e.g., converted gasoline vehicles)
Solution Approach 1:
The control circuit performs a learning process before normal operation to detect the actual rotational speed change of the motor during shift changes. This preliminary detection allows the system to acquire vehicle-specific characteristics and store them for future use, enabling adaptation to different vehicle configurations without requiring pre-programmed data for each possible configuration.
Solution Approach 2:
The control circuit uses feedback from the learning process to adjust the target rotational speed setting. By detecting the actual rotational speed change during shift changes and using this information to set the target rotational speed, the system continuously optimizes its control parameters based on real vehicle characteristics, thereby achieving adaptability across different vehicle types.
2Reliability
If the control circuit uses pre-set target rotational speeds, then control is simple, but it cannot reduce shift shock in vehicles where appropriate rotational speed is unknown
Solution Approach 1:
The system performs a learning process during initial operation to detect and store the actual rotational speed characteristics of the motor during shift changes. This preliminary detection phase allows the system to acquire vehicle-specific data without requiring pre-existing knowledge of appropriate rotational speeds, thereby enabling reliable shift shock reduction in converted vehicles.
Solution Approach 2:
The control circuit automatically determines the appropriate target rotational speed by using feedback from the learning process. The system serves itself by detecting its own operational characteristics and using this information to optimize control parameters, eliminating the need for external calibration or pre-programming for each vehicle configuration.
3Adaptability or versatility
If the system performs a learning process to detect rotational speed changes, then it can adapt to different vehicle characteristics, but this requires additional detection and control processes
Solution Approach 1:
The control circuit serves multiple functions: it detects rotational speed changes during the learning process, stores the detected characteristics, and uses this information to set target rotational speeds during normal operation. By integrating these functions into a single control unit, the system achieves adaptability without proportionally increasing overall system complexity.
Solution Approach 2:
The learning process uses feedback from rotational speed sensors to detect actual motor behavior during shift changes. This feedback mechanism allows the system to automatically adapt to different vehicle configurations without requiring complex manual calibration procedures or additional hardware components.
Data Source
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AI summary
An electrified vehicle includes a motor (10), a clutch (20), a transmission (30), a rotational speed sensor (60) configured to detect a rotational speed of the motor (10), and a control circuit (50) configured to control the motor (10). The control circuit (50) performs: a learning process of detecting a change in the rotational speed of the motor (10) by the rotational speed sensor (60) when the shift change is performed; and a control process of controlling the rotational speed of the motor (10) based on the change in the rotational speed detected in the learning process, when the shift change is performed after the learning process.