Stator Coil Drive Signal Harmonic Control for Electromechanical Transducer Noise
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Solution Overview
Problem
Permanent magnet (PM) electromechanical transducers in wind turbines face challenges with cogging torque and radial force/pressure ripples, leading to unwanted vibrations and acoustic noise, which are difficult to minimize with a single design, especially under variable rotational speeds.
Innovation Solution
A method that determines the strength of harmonic operational behavior at different times, calculates a harmonic control signal, and generates a modified drive signal with an AC component to supply to the stator coils, effectively reducing the excitation source of unwanted vibrations and noise by minimizing torque ripple and radial force/pressure ripple oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent magnets are used in the rotor to eliminate commutators and brushes, then efficiency and reliability are improved, but cogging torque and radial force ripple are introduced causing vibrations and noise
Solution Approach 1:
The patent applies parameter changes by modifying the drive signal parameters (adding harmonic components at specific frequencies and amplitudes) to counteract the cogging torque and radial force ripple. The control system dynamically adjusts the drive signal parameters based on detected vibration and noise levels, transforming the harmful periodic forces into controllable parameters that can be compensated through signal modification.
2Object-generated harmful factors
If mechanical parts are designed to place resonance frequencies outside the excited range, then vibrations are reduced, but this approach is ineffective when the transducer operates with variable rotational speed across a wide frequency range
Solution Approach 1:
The patent applies dynamics by implementing a dynamic control system that continuously adapts the drive signal parameters based on the current operating conditions. The control system detects vibration and noise levels in real-time and dynamically adjusts the harmonic components of the drive signal, allowing the system to maintain effective vibration and noise reduction across the entire variable speed range without requiring fixed mechanical resonance tuning.
3Object-generated harmful factors
If harmonic components are added to the drive signal to reduce noise and vibrations, then acoustic noise and vibrations are reduced, but control system complexity increases
Solution Approach 1:
The patent implements feedback by using sensors to detect vibration and noise levels generated by the motor, then feeding this information back to the control system. The control system processes this feedback and dynamically adjusts the harmonic components of the drive signal to minimize the detected noise and vibrations, creating a closed-loop control system that automatically optimizes performance based on actual operating conditions.
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 approach significantly reduces acoustic noise and vibrations in PM-electric generators by eliminating the excitation sources of harmonic operational behavior, minimizing torque ripple and radial force/pressure ripple, and does so without requiring additional hardware or significant electric losses.
Implementation Method 1
An electromechanical transducer comprises a stator and a rotor. The stator is an assembly, which represents the stationary part of an electromechanical transducer. The rotor is an assembly, which represents the moving and in particular the rotating part of an electromechanical transducer. In order to provide magnetic field linkage, permanent magnets may be used in particular for a rotor of an electromechanical transducer.
Data Source
AI summary
A method for controlling the operation of an electromechanical transducer is provided. The method includes (a) determining during a first period of time a first strength of the harmonic operational behavior of the transducer, (b) determining during a second period of time a second strength of the harmonic operational behavior of the transducer, wherein the second period of time is different from the first period of time, (c) calculating a harmonic control signal in response to both the determined first strength of the harmonic operational behavior and the determined second strength of the harmonic operational behavior, (d) generating a modified drive signal based on the calculated harmonic control signal, and (f) supplying the generated modified drive signal to electromagnetic coils of a stator of the transducer. Further, a corresponding control system for controlling the operation of an electromechanical transducer is provided.