Dynamometer Control Device Resolving Torsional Vibration Trade-offs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing dynamometer control devices face instability and reduced responsiveness due to torsional vibration, limiting the ability to achieve high-frequency electrical inertia control effectively.
Innovation Solution
A dynamometer control device with a shaft torque controller and inertia compensator, utilizing first and second low-pass filters to generate a torque command signal, and incorporating a non-integration operation part to suppress mechanical resonance, allowing for highly responsive electrical inertia control by adjusting the input-output characteristics of the filters and using μ design or H∞ control methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a low-pass filter with cut-off frequency of approximately 20 Hz is used to prevent instability due to torsional vibration, then stability of the low-inertia realizing control is improved, but responsiveness of the electrical inertia control deteriorates
Solution Approach 1:
The patent divides the control system into multiple independent control loops: a shaft torque control loop that handles high-frequency torsional vibrations and an electrical inertia control loop that handles low-frequency inertia simulation. Each loop has its own controller and appropriate filter characteristics, allowing them to operate independently without interfering with each other's performance.
Solution Approach 2:
The patent introduces a variable cut-off frequency mechanism where the low-pass filter's cut-off frequency is dynamically adjusted based on the operating conditions. During transient states when responsiveness is critical, the cut-off frequency is increased to allow higher frequencies to pass, while during steady-state operation, the cut-off frequency is reduced to enhance stability.
2Measurement precision
If the dynamometer moment of inertia is reduced to match the engine moment of inertia, then accuracy of test simulation is improved, but stability of the control system deteriorates due to torsional vibration
Solution Approach 1:
The patent introduces a shaft torque controller as an intermediary between the electrical inertia controller and the dynamometer actuator. This intermediary controller specifically targets and suppresses torsional vibrations in the input shaft, allowing the system to use reduced dynamometer inertia for accurate engine simulation while maintaining stability through active vibration suppression.
Solution Approach 2:
The patent replaces the traditional mechanical inertia matching approach with an electrical control-based solution. Instead of physically matching the dynamometer's moment of inertia to the engine's moment of inertia, the system uses electronic control algorithms and feedback mechanisms to simulate the desired inertial characteristics while actively suppressing harmful vibrations.
Data Source
AI summary
In the present invention, an input-side control device generates an input-side torque command signal Tr using an engine torque command signal, an input-side velocity detection signal ω, and an input-side shaft torque detection signal Tsh, and is provided with: a shaft torque controller that generates a torque command signal on the basis of the engine torque command signal and an input shaft torque detection signal; and an inertia compensator that feeds back an inertia compensation signal generated by multiplying a set inertia value Jset by the input-side velocity detection signal. The shaft torque controller is provided with a first low-pass filter that, from the engine torque command signal, allows a high-frequency component to decay; and the inertia compensator is provided with a second low-pass filter that, from the input-side velocity detection signal, allows a high-frequency component to decay.