PMSM Parameter Estimation Using Closed-Form Analytical Solutions

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Solution Overview

Problem

Current methods for modeling and simulating permanent magnet synchronous motors (PMSM) face challenges in accurately estimating unknown parametric values, which are crucial for developing and testing dynamic controller models, especially in the presence of magnetic saturation and varying operational conditions.

Innovation Solution

The techniques involve using non-iterative algorithms to estimate missing parametric values such as d-axis inductance, q-axis inductance, magnetic flux, and stator resistance based on known parameters like power, rated speed, and torque, utilizing graphical user interfaces and technical computing environments to create a lumped parameter model that can simulate closed-loop systems, including dynamic controllers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional iterative methods are used to estimate parametric values, then measurement precision may be improved, but loss of time increases significantly

Engineering Contradiction:
Improveparametric value estimation accuracyVSAvoidcomputation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces traditional iterative computational methods with a closed-form analytical solution. Instead of using mechanical iterative algorithms that require repeated calculations and convergence checks, the invention derives direct mathematical expressions that compute parametric values (inductance, resistance, flux) immediately from measurable quantities like terminal voltages, currents, and speeds, thereby eliminating time-consuming iteration while maintaining estimation accuracy

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs preliminary algebraic manipulation and mathematical derivation to establish closed-form expressions before actual parameter estimation is needed. By pre-deriving the analytical relationships between measurable quantities and unknown parameters, the system avoids performing complex iterative calculations during runtime, thus reducing computation time while preserving measurement precision

Inventive Principle:
Principle #10Preliminary action

2Reliability

If detailed parametric values are estimated accurately, then simulation fidelity is improved, but device complexity increases

Engineering Contradiction:
Improvesimulation fidelityVSAvoidmodeling complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential parametric values needed for accurate PMSM simulation (d-axis and q-axis inductance, stator resistance, and flux linkage) from the complex motor system. By focusing on extracting these specific critical parameters through simplified analytical relationships rather than attempting to model all motor characteristics, the system achieves high simulation fidelity without requiring complex measurement setups or sophisticated identification procedures

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the approach from iterative numerical parameter identification to direct analytical parameter calculation. By transforming the estimation problem into closed-form mathematical expressions that directly compute parameters from measurable quantities, the invention reduces modeling complexity while maintaining the ability to capture essential motor behavior for accurate simulation

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If iterative algorithms are used for parameter estimation, then measurement precision improves, but productivity decreases

Engineering Contradiction:
Improveparameter estimation accuracyVSAvoidmodeling efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent substitutes iterative computational algorithms with closed-form analytical solutions. The derived mathematical expressions directly calculate parametric values without requiring repeated iterations, convergence criteria, or numerical optimization, thereby maintaining estimation precision while dramatically improving modeling efficiency and reducing computational resources required

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent skips the iterative calculation process entirely by using direct analytical expressions. Instead of rushing through multiple iteration cycles to converge on parameter values, the invention computes the desired parameters immediately in a single calculation step, thus improving productivity without sacrificing measurement precision

Inventive Principle:
Principle #21Skipping (Rushing through)

Data Source

PatentUS10725440B1Systems and method for parameter estimation for a permanent magnet synchronous machine
Publication Date: 2020.07.28 MATHWORKS INC
  • US10725440B1 patent drawing
  • US10725440B1 patent drawing
  • US10725440B1 patent drawing

AI summary

Embodiments include techniques for estimating unknown or missing values for parameters of a motor based on high-level motor information and using the estimated parametric values in generating an executable model for modeling the behavior of the motor. An aspect of the techniques involves assumptions used to establish the predetermined parametric values that are applied to the algorithm for deriving estimates of the unknown parametric values for the motor. The estimated parametric values may then be used in the executable model of the motor to enable development and simulation of a plant (e.g., a closed loop system) including a plant model having a dynamic controller model and a lumped parameter model of a modeling environment of a technical computing environment executing on a data processing system. The simulation of the plant loop can be sufficient to test the dynamic (e.g., feedback-based) controller within a closed loop system, e.g., test motion control of a motorized vehicle seat.