Motor Control Apparatus Using Dynamic Rotor Vibration Properties
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Solution Overview
Problem
Conventional motor control apparatuses fail to sufficiently reduce motor noise due to variations in the natural vibration properties of the rotor as it rotates, caused by centrifugal force altering the rotor's rigidity and natural vibration frequencies.
Innovation Solution
A motor control apparatus that includes a fundamental voltage generator, a property storage unit to store the rotor's rotating vibration properties, and a harmonic voltage generator to superimpose a harmonic voltage based on the rotating state and vibration properties, ensuring the harmonic voltage command reflects the rotor's natural vibration while rotating, thereby reducing noise effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a harmonic voltage is superimposed on a fundamental voltage based on the rotor's natural vibration property at rest, then motor noise reduction is attempted, but the noise reduction is insufficient because the rotor's natural vibration property changes during rotation
Solution Approach 1:
The patent applies the dynamics principle by transitioning from using static natural vibration properties (at rest) to using dynamic natural vibration properties (during rotation). The control apparatus acquires and stores natural vibration properties at different rotational speeds, then selects the appropriate dynamic property based on the current rotational speed to generate the harmonic voltage command. This ensures the harmonic voltage continuously matches the rotor's actual vibration characteristics during operation, resolving the insufficiency of noise reduction caused by using static properties.
Solution Approach 2:
The patent implements parameter changes by varying the natural vibration property parameter according to the rotor's rotational speed. Instead of using a fixed natural vibration property value, the system stores multiple natural vibration property values corresponding to different rotational speeds and dynamically selects the appropriate parameter based on the current operating condition. This parameter adaptation ensures the harmonic voltage command remains effective across the entire operational range, directly addressing the noise reduction insufficiency.
2Productivity
If the rotor rotates at high speed, then productivity increases, but centrifugal force deforms the rotor and changes its rigidity and natural vibration property
Solution Approach 1:
The patent applies dynamics by recognizing that rotor rigidity is not a static property but changes dynamically with rotational speed due to centrifugal force. The system acquires natural vibration properties at multiple rotational speeds and uses the property corresponding to the current speed to generate the harmonic voltage command. This dynamic adaptation compensates for the rigidity changes caused by high-speed rotation, maintaining effective noise control across the full productivity range.
Solution Approach 2:
The patent implements feedback by using the detected rotational speed as input to select the appropriate natural vibration property from stored values. The rotational speed detection creates a feedback loop where the system continuously monitors its operating state and adjusts the harmonic voltage generation parameters accordingly. This feedback mechanism ensures that despite centrifugal deformation at high speeds, the noise control remains effective by always using the current state's natural vibration property.
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
This configuration reliably reduces motor noise caused by rotating rotor vibrations by accurately accounting for the changing natural vibration properties during rotation, leading to improved noise reduction compared to conventional methods.
Implementation Method 1
magnetic interactions between a stator magnetic field generated by the stator coil and the rotor magnetic field rotate the rotor
Implementation Method 2
Rotation of the rotor may cause centrifugal force to deform the rotor. This may result in change of the rigidity of the rotor
Data Source
AI summary
In a control apparatus, a fundamental voltage generator generates, based on a target rotational speed, a fundamental voltage command for a fundamental voltage. A property storage stores a natural vibration property of a rotor when the rotor is rotating as a rotating vibration property. A rotating state detector detects a rotating position and a rotational speed of the rotor as a rotating state of the rotor. A harmonic voltage generator generates, based on the rotating state of the rotor and the rotating vibration property, a harmonic voltage command to be superimposed on the fundamental voltage command generated by the fundamental voltage generator.