Poly-Phase Motor Control Using Active Harmonic Planes
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Solution Overview
Problem
Traditional field-oriented control (FOC) methods for poly-phase motor systems are limited in achieving high efficiency and power density due to excessive power losses from harmonic currents in stator windings without corresponding torque output, especially in induction machines, where harmonic injection techniques are often avoided.
Innovation Solution
Implementing a multi-harmonic field-oriented control mechanism that integrates harmonic injection techniques with FOC to generate torque at multiple frequencies, utilizing active harmonic planes and synchronization control to coordinate current control across different harmonic planes, thereby improving torque output and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional FOC method based on fundamental frequency is used, then control simplicity is maintained, but voltage capability and performance are limited
Solution Approach 1:
The patent segments the control into multiple independent harmonic planes (fundamental plane, 5th harmonic plane, 7th harmonic plane, etc.), where each plane is controlled separately using FOC. This allows harmonic currents to be intentionally injected to improve voltage capability while maintaining manageable control complexity through modular independent control of each harmonic component.
Solution Approach 2:
The patent extends the traditional single-frequency FOC control into multiple frequency dimensions by introducing harmonic planes. Instead of controlling only the fundamental frequency, the system now operates in a multi-dimensional frequency space, enabling simultaneous control of fundamental and harmonic components to achieve superior voltage capability and performance.
2Power
If harmonic injection techniques are used to improve voltage capability, then voltage capability is enhanced, but power losses increase due to excessive harmonic currents in rotor without torque output
Solution Approach 1:
The patent converts the traditionally harmful harmonic currents (which caused excessive power losses without torque output) into beneficial components by intentionally injecting controlled harmonic currents at specific frequencies (5th, 7th, 11th, 13th harmonics) that are designed to produce both voltage capability enhancement and useful torque output. The harmonic plane synchronization control ensures these harmonic currents contribute constructively to torque generation rather than causing losses.
Solution Approach 2:
The patent changes the operational parameters by introducing controlled harmonic current components at specific frequencies and amplitudes. By adjusting the harmonic current magnitudes and phases through the harmonic plane synchronization control, the system optimizes the balance between voltage capability enhancement and power loss minimization, ensuring harmonic currents produce both voltage boost and useful torque.
3Power
If harmonic currents are injected to improve performance, then voltage capability increases, but torque output coordination becomes complex across multiple frequencies
Solution Approach 1:
The patent segments the multi-frequency torque production into independent harmonic plane controls, where each harmonic plane (fundamental, 5th, 7th, 11th, 13th) is controlled separately. This segmentation simplifies the coordination complexity by allowing independent optimization of each harmonic component while maintaining overall torque synthesis through the synchronization control mechanism.
Solution Approach 2:
The patent implements harmonic plane synchronization control that monitors and coordinates the torque components from different harmonic planes. This feedback mechanism ensures that the harmonic currents at multiple frequencies are coordinated to produce the desired total torque output, adjusting harmonic current magnitudes and phases based on the synchronization requirements to maintain optimal torque production across all frequency components.
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 enhances the operational performance of poly-phase motor systems by effectively transferring power and generating torque across multiple harmonic frequencies, reducing power losses and improving overall efficiency and power density.
Implementation Method 1
a plurality of power converters connected to respective windings, wherein the plurality of power converters is configured to control currents of the plurality of windings
Implementation Method 2
a rotor and a stator magnetically coupled to the rotor
Data Source
AI summary
A method includes configuring a motor drive system with a motor/generator with a plurality of windings and coupling the plurality of windings to an inverter, configuring a plurality of active harmonic planes in a controller of the inverter to control a torque through controlling a magnetizing component and/or a torque component of winding currents on each active harmonic plane, and inserting a smooth transition between a first operating mode and a second operating mode of the motor/generator such that on at least one of the plurality of active harmonic planes, the magnetizing component of the winding currents changes in a sinusoidal fashion during the smooth transition.