Asymmetric Minor Hysteresis Loop Model for Inductor Simulation
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Solution Overview
Problem
Conventional techniques for modeling inductors, such as the Jiles-Atherton and Chan methods, face issues with computational efficiency and non-physical behavior in simulating asymmetric minor hysteresis loops, which affect the accuracy of circuit simulations and are not parameterized by typical ferromagnetic material parameters.
Innovation Solution
A method is developed to model the ferromagnetic core of an inductor or transformer by obtaining upper and lower branch functions for the major hysteresis loop, determining symmetric minor hysteresis loops, and constructing asymmetric minor hysteresis loops using an affine map or basis function, ensuring the loops do not extend beyond the major loop bounds, thus avoiding non-physical behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Jiles-Atherton technique is used to model hysteresis loops, then accuracy is improved, but computational speed deteriorates due to transcendental math functions
Solution Approach 1:
The patent transforms the hysteresis loop modeling approach by changing from transcendental parameter representations to algebraic parameter representations. The new model uses piecewise linear functions with parameters directly derived from ferromagnetic material properties (coercive force, remnant magnetization flux density, saturation flux density), eliminating the need for transcendental functions while maintaining accuracy and significantly improving computational speed.
2Productivity
If the Chan method is used for lightweight modeling, then computational efficiency is improved, but physical accuracy deteriorates due to non-physical behavior in asymmetric minor loops
Solution Approach 1:
The patent addresses the asymmetry in hysteresis loops by developing separate upper and lower branch functions that independently capture the asymmetric behavior. The model uses asymmetric piecewise linear functions with different slopes and intercepts for the upper and lower branches, allowing accurate representation of asymmetric minor loops without the non-physical extensions that occur in the Chan method. This asymmetric formulation ensures that minor loops remain within the bounds of the major loop.
3Device complexity
If asymmetric minor hysteresis loops are modeled using Chan's technique, then computational lightweight modeling is achieved, but non-physical behavior occurs where loops extend beyond major loop bounds
Solution Approach 1:
The patent introduces an intermediary constraint mechanism that prevents minor hysteresis loops from extending beyond the major loop bounds. By using piecewise linear functions with specifically constructed parameters and enforcing boundary conditions through the model structure, the patent creates an intermediary layer of control that ensures physical validity. The model uses the major loop parameters as intermediary constraints to bound the minor loop behavior, eliminating non-physical extensions while maintaining computational efficiency.
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 provides a computationally lightweight and accurate simulation of inductors without non-physical behavior, using parameters like coercive force, remnant magnetization flux density, and saturation flux density, improving the accuracy of circuit simulations.
Implementation Method 1
modeling the ferromagnetic core of an inductor or transformer... obtaining upper and lower branch functions for the major hysteresis loop... determining symmetric minor hysteresis loops... constructing asymmetric minor hysteresis loops
Data Source
AI summary
The present disclosure relates to simulating inductors wound on a ferromagnetic core as the magnetic material saturates. In one application, the present disclosure is advantageously used to model the asymmetric minor hysteresis loops commonly traversed by the output inductor of a switch mode power supply. An advantage of the subject matter of the disclosure is that it allows practical nonlinear inductors to be modeled in a computationally lightweight manner without conventional non-physical behavior under asymmetric minor hysteresis loop traversals. The disclosure is also conveniently applicable to practical ferromagnetic core materials because, in one particular implementation, the input parameters to the model are the core's coercive force (Hc), remnant magnetization flux density (Br), and saturation flux density (Bs).