Torque Command Generation Device for Drivetrain Test Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing torque command generation devices in drivetrain test systems face issues with torque limiting, leading to reduced average torque and excitation force due to surplus torque being discarded, which affects acceleration and deceleration performance.
Innovation Solution
A torque command generation device that calculates a limit value based on motor revolution speed and generates a motor-generated-torque command signal by composing a DC signal and an AC signal, ensuring the signal does not exceed the limit value, thereby preventing unintended discarding and maintaining intended torque levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If torque limiting function is implemented in motor driving device to protect devices, then device reliability is improved, but average torque deviates from intended magnitude and excitation force declines
Solution Approach 1:
The torque command generation device performs preliminary calculation of the maximum torque upper limit value based on motor revolution speed before generating the torque command signal. By pre-determining the allowable torque range and adjusting the AC signal amplitude accordingly, the system prevents torque exceeding the limit rather than correcting it afterward, thereby maintaining both device safety and intended torque characteristics.
Solution Approach 2:
The system uses feedback from the motor revolution speed to dynamically adjust the maximum torque upper limit value. The torque command generation device continuously monitors motor speed and adjusts the AC signal amplitude based on the calculated limit value, creating a closed-loop control that maintains average torque within intended magnitude while protecting against excessive torque.
2Reliability
If AC signal amplitude is reduced to prevent torque exceeding limit value, then device protection is improved, but excitation force and acceleration performance deteriorate
Solution Approach 1:
The system dynamically adjusts the AC signal amplitude based on real-time motor revolution speed. As motor speed changes, the maximum torque upper limit value is recalculated and the AC signal amplitude is adjusted accordingly. This dynamic adaptation allows the system to maintain maximum excitation force at each operating point while ensuring torque never exceeds the calculated limit value, thereby preserving acceleration performance without compromising device protection.
3Power
If torque command signal exceeds maximum torque upper limit value, then excitation force is maximized, but torque limiting function causes surplus torque to be discarded and average torque to shift
Solution Approach 1:
The torque command generation device calculates the maximum torque upper limit value based on motor revolution speed before generating the torque command signal. By pre-determining the allowable torque range and adjusting the AC signal amplitude to ensure the command signal does not exceed this limit, the system eliminates the need for subsequent torque discarding while maintaining both excitation force and torque accuracy.
Data Source
AI summary
The purpose of the present invention is to provide a torque command generation device for generating a motor-generated-torque command that makes it possible to maximize excitation force while ensuring necessary acceleration, and the like, within a limited motor torque range. A torque command generation device (6) is provided with: a maximum torque calculation unit (633) for calculating, according to a motor speed, a maximum torque value for a motor-generated-torque-command signal value; a DC component limiter (635) for calculating a DC signal value; a surplus amplitude calculation unit (637) for calculating a surplus amplitude by subtracting the maximum torque value from the sum of the DC component value calculated by the DC component limiter (635) and an externally input excitation amplitude; a sine-wave transmitter (639) for generating a sine wave having an amplitude obtained by subtracting the surplus amplitude from a base amplitude; and a summing unit (640) for calculating the motor-generated-torque-command signal value by adding the DC component value and the sine wave value.