Frequency Converter Control of Electric Machine Lateral Vibration
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Solution Overview
Problem
Existing methods for controlling lateral vibration in electric machines are inefficient and costly, making it difficult to effectively manage vibrations in industrial applications, particularly in variable frequency drive motors with flexible foundations.
Innovation Solution
A method and arrangement using vibration sensors to measure lateral vibrations, a frequency converter to determine control torque, and exerting this torque on the stator to suppress horizontal vibrations, thereby controlling the machine's displacement and reducing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional structural design methods are used to avoid resonances, then the dimensions of critical structural members are adjusted, but additional damping elements are only introduced in exceptional cases and the solution is costly and complex
Solution Approach 1:
The patent replaces traditional mechanical vibration control methods (structural design adjustments and physical damping elements) with an electrical control system. The frequency converter generates control torques based on measured vibration data to actively suppress vibrations, eliminating the need for complex structural modifications or additional mechanical damping components.
Solution Approach 2:
The vibration control system uses the electric machine's own control system (frequency converter) to generate control torques for vibration suppression. The system measures its own vibration through sensors and automatically generates compensating torques, making the electric machine self-regulating without requiring external mechanical intervention.
2Reliability
If active vibration control solutions like active magnetic bearings are used, then vibration control effectiveness is improved, but the cost increases significantly
Solution Approach 1:
The patent makes the frequency converter perform multiple functions: it not only controls the motor speed and torque but also simultaneously acts as a vibration control system. By utilizing the existing frequency converter infrastructure, the system achieves active vibration control without requiring separate expensive active magnetic bearing systems.
Solution Approach 2:
The patent introduces control torques as an intermediary mechanism to achieve vibration suppression. Instead of directly mechanically supporting the rotor like active magnetic bearings, the system uses electrical control torques generated by the frequency converter to counteract vibrations, providing a cost-effective intermediary solution.
3Reliability
If resonance avoidance is achieved by separating critical speeds from operating speed range, then vibration is reduced, but this is difficult to achieve with flexible foundations and large operating speed ranges
Solution Approach 1:
The patent transitions from a static resonance avoidance approach (fixed structural design) to a dynamic control approach. The system continuously measures vibrations and adjusts control torques in real-time based on operating conditions, allowing the electric machine to maintain vibration control across varying speeds and flexible foundation conditions.
Solution Approach 2:
The system changes the control parameter from fixed structural dimensions to variable control torques. By dynamically adjusting the control torque magnitude and frequency based on measured vibrations, the system can effectively control resonance across a wide operating speed range regardless of foundation flexibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution efficiently suppresses horizontal vibrations, enhances vibration performance, increases operating speed range, extends bearing life, reduces structural noise, and optimizes electric machine operation without requiring design changes.
Implementation Method 1
lateral vibration from said electric machine is measured by one or more vibration sensors as measured vibration data
Implementation Method 2
control torque is generated by said frequency converter and exerted on the stator of said electric machine
Data Source
AI summary
A field of electric drive devices and electric machines, such as electric motors and electric generators for industrial applications, and more particularly to a method, an arrangement and a frequency converter for controlling lateral vibration of an electric machine. The arrangement of the present invention for controlling lateral vibration of an electric machine includes a frequency converter, one or more vibration sensors and an electric machine, wherein the one or more vibration sensors is/are arranged for measuring the lateral vibration from the electric machine and for producing measured vibration data; and wherein the frequency converter is arranged for generating a control torque for exerting the control torque on the stator of the electric machine, the control torque being determined utilizing the measured vibration data.