Five-Phase Machine Torque Control via Harmonic Optimization
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Solution Overview
Problem
Conventional polyphase rotating electric machines with fewer than five phases are limited in utilizing third harmonic currents for torque production due to low magnetic flux density and electromotive force harmonics, resulting in inefficient torque generation.
Innovation Solution
A polyphase rotating electric machine with at least five phases, featuring a control system that sets specific current harmonics to maximize electromagnetic torque, with a high winding factor for the third harmonic and optimized rotor magnetic flux density distribution to enhance torque production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional three-phase machine is used, then the machine structure is simple, but the third harmonic of electromotive force cannot be utilized for torque production
Solution Approach 1:
The patent changes the fundamental parameter of phase number from three to five or more phases. This parameter change enables the machine to utilize third harmonic currents for torque production, as the fifth-phase configuration allows independent control of fundamental and third harmonic current components, transforming the machine from unable to utilize third harmonics to actively leveraging them for enhanced torque.
Solution Approach 2:
The patent introduces an additional dimensional aspect by separating torque production into two independent control dimensions: one for fundamental frequency currents and another for third harmonic currents. This dimensional separation allows simultaneous optimization of both fundamental torque and third harmonic torque contributions, effectively adding a new degree of freedom to the control system.
2Power
If a five-phase or more machine is used, then the third harmonic of electromotive force can be utilized to increase torque, but the device complexity increases
Solution Approach 1:
The patent makes the control system universal by designing it to handle both fundamental frequency and third harmonic frequency components simultaneously. The control apparatus is configured to process multiple frequency components through a unified control framework, allowing the same control system to manage both the main torque-producing fundamental currents and the torque-enhancing third harmonic currents without requiring separate dedicated systems.
Solution Approach 2:
The patent merges the control of fundamental currents and third harmonic currents into a single integrated control system. Rather than using separate control systems for different frequency components, the invention combines both control functions into one unified apparatus that processes and regulates both current types simultaneously, thereby reducing overall system complexity despite the increased phase count.
3Adaptability or versatility
If the number of phases is increased to five or more, then independent control of fundamental and third harmonic currents becomes possible, but the control system complexity increases
Solution Approach 1:
The patent segments the control function into distinct processing paths for fundamental frequency components and third harmonic frequency components. The control system separates the analysis and regulation of these different frequency components, allowing independent optimization of each while maintaining overall system coordination. This segmentation enables versatile control without requiring the entire control system to be overly complex.
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 significantly increases the third harmonic of electromotive force and torque produced by the machine, achieving a higher total torque through independent control of fictitious machines driven by first and third current harmonics.
Implementation Method 1
a rotor configured so as to maximize a third harmonic of a rotor magnetic flux density in an air gap of an electric machine separating a stator from the rotor
Data Source
Figure 1a~1d
Figure 2a~5b
Figure 6~8
AI summary
The invention relates mainly to a polyphase rotating electrical machine with at least five phases comprising a rotor comprising a set of principal poles of alternating polarities and a stator separated from said rotor by an air gap, characterized in that it comprises a control system (35) comprising, for each phase, a control system (35A-35E) capable of determining a first (I1r.A-I1r.E) and a third (I3r.AI3r.E) harmonics of setpoint current whose effective values depend on an effective value of a current (Ieffcace) flowing through the machine and a ratio, said ratio depending on a ratio between a maximum amplitude of a first and a third harmonic of electromotive force of the electrical machine, so as to maximize an electromagnetic torque produced by the electrical machine.