Electric Machine Harmonic Control for Vibration and Noise Suppression
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Solution Overview
Problem
Existing methods for controlling electric machines struggle to robustly and stably manage harmonics, leading to vibrations and noise due to non-ideal sinusoidal magnetic fields and mechanical transmission behaviors.
Innovation Solution
A harmonic controller system that transforms feedback variables into a harmonic-oriented system, allowing for precise control of DC manipulated variables, which are then transformed back into the field-oriented system to energize the electric machine, effectively compensating for harmonic disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If field-oriented control is used to control electric machines, then the control of fundamental sinusoidal phase currents is achieved, but harmonic disturbances cause vibrations and noise
Solution Approach 1:
The control system is segmented into two independent parts: a field-oriented controller for fundamental sinusoidal phase currents and a harmonic controller for harmonic suppression. This segmentation allows each controller to specialize in its function without interference, resolving the contradiction by separating the control of fundamentals from the suppression of harmonics.
Solution Approach 2:
A harmonic-oriented coordinate system is introduced as an intermediary transformation between the field-oriented system and the time domain. This intermediary system allows harmonic components to be controlled independently by transforming them into a rotating reference frame where they appear as DC quantities, enabling precise harmonic suppression while maintaining fundamental control.
2Reliability
If harmonics are controlled in the field-oriented system, then harmonic suppression is achieved, but the control becomes complex due to AC variable manipulation
Solution Approach 1:
The coordinate system is dynamically adapted to rotate at k times the fundamental frequency for harmonic control, then synchronized with the fundamental frequency for implementation. This dynamic transformation converts time-varying AC harmonic components into stationary DC-like quantities in the harmonic-oriented system, simplifying the control logic while maintaining reliability.
Solution Approach 2:
The control approach changes the reference frame parameters by introducing a harmonic-oriented coordinate system with different rotation characteristics. This parameter change transforms the mathematical representation of harmonics from complex time-varying AC signals to simpler DC-like signals, reducing control complexity while improving suppression reliability.
3Adaptability or versatility
If multiple frequency components are controlled simultaneously, then comprehensive harmonic suppression is achieved, but the response dynamics slow down
Solution Approach 1:
The control system segments different frequency components by using separate coordinate systems: the field-oriented system for fundamentals and the harmonic-oriented system for harmonics. This segmentation allows independent optimization of control dynamics for each frequency range, achieving comprehensive coverage without sacrificing response speed.
Solution Approach 2:
The harmonic controller operates in parallel with the field-oriented controller, performing preliminary harmonic suppression actions simultaneously with fundamental control. This preliminary action on harmonic components ensures that both fundamentals and harmonics are controlled without sequential delays, maintaining fast response dynamics while achieving versatile frequency coverage.
Data Source
AI summary
The invention relates to a method (400) for regulating an electric machine (190) comprising a harmonic regulator (100), wherein the harmonic regulator comprises an input transformer (110), a regulator (120), and an output transformer (130). The method has the steps of: ascertaining (410) a feedback variable (Idq); transforming (420) the feedback variable (Idq); ascertaining (430) a regulating deviation; ascertaining (440) an equalization variable (UHrmc*); back-transforming (450) the equalization variable (UHrmc*); and energizing (480) at least one winding of the electric machine (190) on the basis of the actuating variable (UdqHrmc*).