Adaptive Speed Controller for Elevator Drive Systems
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Solution Overview
Problem
Conventional drive systems for electric motors, particularly in high-speed elevators, face challenges in achieving quick response times during speed changes while maintaining smooth operation and passenger comfort, often requiring a compromise between response time and driving comfort that can lead to malfunctions or increased noise.
Innovation Solution
A drive system with a frequency converter and a speed controller that adjusts its operating parameters to provide different response times based on the motor's state, such as accelerating, constant speed, or decelerating, allowing for faster responses during changes and slower responses at constant speeds to improve smoothness and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the speed controller responds quickly to changes in speed reference, then the response time is improved, but the driving comfort deteriorates due to increased noise and vibration
Solution Approach 1:
The patent applies dynamics by making the operating parameters of the speed controller variable rather than fixed. The controller dynamically adjusts parameters such as proportional gain, integral gain, and filter coefficients based on the current operating state (acceleration, constant speed, deceleration). This allows the system to have quick response during speed changes while maintaining smooth operation during constant speed, resolving the contradiction between response time and driving comfort.
Solution Approach 2:
The patent changes the parameters of the speed controller based on operating conditions. During acceleration and deceleration phases, the controller uses parameter sets optimized for quick response. During constant speed operation, it switches to parameter sets that prioritize smooth operation and noise reduction. This parameter adaptation resolves the technical contradiction by having different parameter configurations for different operational requirements.
2Ease of operation
If the speed controller responds slowly during constant speed, then the driving comfort is improved, but the response time deteriorates when speed changes are needed
Solution Approach 1:
The controller dynamically switches between different operating modes with optimized parameters. During constant speed operation, it uses parameters that provide smooth control and comfort. When speed changes are detected or anticipated, it transitions to parameters that enable quick response. This dynamic adaptation resolves the contradiction by having the system be slow only when comfort is needed and fast when response is needed.
Solution Approach 2:
The controller periodically evaluates the operating state and adjusts parameters accordingly. It monitors whether the system is in acceleration, constant speed, or deceleration phase and switches parameter sets at appropriate intervals. This periodic adjustment ensures the system maintains optimal characteristics for the current phase, resolving the contradiction between slow response during constant speed and quick response during transitions.
3Device complexity
If fixed operating parameters are used in the speed controller, then the device complexity is reduced, but the adaptability deteriorates for different operating conditions
Solution Approach 1:
The patent implements a dynamic parameter adjustment mechanism that automatically selects appropriate operating parameters based on the current state. The controller monitors speed reference changes and operational phase (acceleration, constant speed, deceleration) and automatically switches between pre-defined parameter sets. This dynamic approach provides high adaptability while maintaining relatively simple implementation through predefined parameter configurations.
Solution Approach 2:
The speed controller performs self-adjustment by automatically detecting its operating state and selecting appropriate parameters without external intervention. The system monitors its own performance and operational phase, then autonomously switches between parameter sets optimized for different conditions. This self-service capability provides adaptability across different operating states while keeping the control system relatively simple.
Data Source
AI summary
A drive system for driving an electric motor includes a drive control unit and a frequency converter including a speed controller. The drive control unit is configured to: define a speed reference of the electric motor; preset operating parameters of the speed controller to provide a first response time of the speed controller, before a drive of the electric motor is initiated; adjust at least one operating parameter of the speed controller to provide a second response time of the speed controller, after the speed of the electric motor reaches a constant speed, wherein the second response time is slower than the first response time; and readjust the at least one operating parameter of the speed controller to provide the first response time, before a deceleration from the constant speed is initiated. A method is disclosed for controlling the drive system for driving the electric motor.