Adaptive Torque Feedback Control for Hybrid Vehicle Speed Regulation
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Solution Overview
Problem
Existing control systems for hybrid vehicles face challenges in accurately adjusting the rotational speed of a rotary member due to differential response rates between engine and motor torques, leading to inadequate torque synthesis and potential temperature issues in motor inverters.
Innovation Solution
A control system that calculates and adjusts the torque changes for both engine and motor based on operating conditions, selecting the torque device with the faster response to generate feedback torque, allowing for precise speed control by prioritizing the torque device with the greater changeable torque amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the motor torque is increased or decreased close to limit values before executing feedback control, then the motor torque response is fast, but the available change in motor torque becomes small and required torque cannot be achieved
Solution Approach 1:
The patent applies dynamics by making the feedback gain adaptive rather than fixed. The feedback gain is dynamically adjusted based on the absolute value of the actuator reaction force |Fax|. When |Fax| is small (motor torque near limit), a smaller feedback gain is used to prevent excessive torque changes. When |Fax| is large (motor torque away from limit), a larger feedback gain enables faster response. This dynamic adjustment resolves the contradiction between fast response and available torque change range.
2Power
If the motor speed is high, then the motor operates at high performance, but the change rate of motor torque must be restricted to prevent excessive inverter temperature rise
Solution Approach 1:
The patent applies parameter changes by making the feedback gain a variable parameter that depends on operating conditions (specifically |Fax| and motor speed). At high motor speeds where inverter heating is a concern, the feedback gain is reduced to limit the torque change rate. This allows the motor to operate at high power while preventing excessive temperature rise in the inverter, resolving the contradiction between power output and torque change rate.
3Power
If the engine speed is temporarily changed, then the engine torque can be adjusted, but the slower engine response causes delay in achieving target speed
Solution Approach 1:
The patent applies feedback control to adjust engine speed to a target value. The feedback gain is adaptively set based on |Fax|, allowing the system to achieve target engine speed more effectively. When the engine response is slow, the adaptive feedback mechanism compensates by optimizing the control signal magnitude, enabling the engine torque to be adjusted appropriately despite the inherent slow response characteristic.
4Speed
If the feedback gain is set to achieve fast response, then the torque adjustment is prompt, but the synthesized torque may not be controlled accurately when motor torque is near limit values
Solution Approach 1:
The patent resolves this contradiction through dynamic feedback gain adjustment. The feedback gain is not fixed but varies with operating conditions (|Fax| and motor speed). This dynamic approach allows the system to achieve fast response when conditions permit (large |Fax|, moderate speed) while maintaining accurate synthesized torque control when motor torque is near limits (small |Fax|, high speed), where the gain is automatically reduced to prevent excessive torque changes.
Data Source
AI summary
A control system for a vehicle that executes a feedback control properly to adjust a speed of a predetermined rotary member to a target speed. A controller is configured to: calculate an amount of change in a torque applied to the rotary member by one of the torque devices, in accordance with operating conditions of the torque devices; and calculate an amount of change in the torque applied to the rotary member by another one of the torque devices, based on a target amount of change in a synthesized torque of the torques of the torque devices and the amount of change in the torque applied to the rotary member by one of the torque devices.