Electric Machine Control via Nonlinear Magnetic Circuit Modeling
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Solution Overview
Problem
Existing control devices for electric machines are inaccurate and imprecise, especially when dealing with non-linear media and the presence of permanent magnets, as they rely on outdated models that are not theoretically correct beyond their linear scope.
Innovation Solution
A real-time control device and method that models the behavior of electric machines using functional mappings correlating electrical and mechanical quantities, including winding currents, voltages, magnetic fluxes, and torques, without requiring mathematical transformations, employing numerical or artificial intelligence models to determine control commands for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pseudo-linear machine models based on time-varying inductance matrix are used, then the control device can operate with simple linear combinations of currents, but the model becomes theoretically incorrect when dealing with non-linear media and permanent magnets
Solution Approach 1:
The patent transitions from linear inductance parameters to non-linear magnetic circuit parameters that account for saturation and permanent magnets. The machine model incorporates non-linear relationships between flux and current, allowing accurate representation of magnetic non-linearities while maintaining computational feasibility through simplified equivalent circuits.
Solution Approach 2:
The patent introduces dynamic adaptation of machine parameters based on operating conditions. The control device continuously updates magnetic circuit parameters to reflect changing saturation levels and rotor position, enabling the model to remain accurate across varying load and speed conditions rather than relying on fixed linear parameters.
2Measurement precision
If improved models incorporating non-linear behavior are used, then quantitative results improve in some operating conditions, but the models generate heavily mistaken results when extended beyond their scope of validity
Solution Approach 1:
The patent creates a universal machine model that functions correctly across all operating conditions by incorporating permanent magnets and non-linear magnetic circuits. The equivalent circuit approach provides a unified framework that handles both linear and non-linear regions, eliminating the need for separate models for different operating ranges.
Solution Approach 2:
The control device implements continuous feedback from actual machine behavior to update model parameters. By comparing measured quantities with model predictions and adjusting magnetic circuit parameters accordingly, the system maintains accuracy across the full operating range and automatically adapts when operating conditions change.
3Ease of operation
If traditional control methods are used, then the control device can operate with established procedures, but accuracy and precision are insufficient especially in non-linear conditions
Solution Approach 1:
The patent replaces traditional mechanical control approaches with an electrical equivalent circuit model that directly represents magnetic field behavior. This substitution allows the control device to calculate electromagnetic quantities more accurately by using electrical parameter relationships rather than mechanical analogies, improving precision while maintaining ease of digital implementation.
Data Source
AI summary
A control device for controlling an electric machine with ks windings on a stator and kr windings on a rotor, where ks+kr=n and either ks or kr may be zero, includes an input for receiving commands, an output for outputting control commands to a driver, machine modeling means for modeling behavior of the machine, and decision means connected to the input, output, and machine modeling means for determining the driver control commands. The machine modeling means models behavior of the machine through functional mapping suited for correlating sets of values of electrical and mechanical quantities, sets of values of their total or partial derivatives and/or integral functions with one another. The functional mapping includes an algorithm and/or equation based on at least one state function associated with the electromagnetic field inside the machine and/or based on at least one partial derivative of the state function.