Markov Model Reliability Analysis for Switched Reluctance Motors

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Solution Overview

Problem

Conventional reliability analysis methods for switched reluctance motor drive systems fail to account for fault operation states, making it difficult to assess system reliability after multiple faults, as they simplify operation states into 'normal' and 'failure' without considering intermediate fault conditions.

Innovation Solution

A Markov model-based method is developed to quantify the reliability of switched reluctance motor systems by obtaining a probability matrix and calculating the mean time to failure (MTTF), allowing for the assessment of system operation and reliability after primary and secondary faults.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional reliability block diagram method is used to simplify system operation states into normal and failure states, then the analysis process is simple, but the reliability assessment accuracy deteriorates because fault operation states are ignored

Engineering Contradiction:
Improveanalysis process simplicityVSAvoidreliability assessment accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system operation states are segmented into multiple distinct states including normal operation state, fault operation states (with different numbers of failed phases), and failure state. This segmentation allows the Markov model to track transitions through intermediate fault states, providing accurate reliability assessment while maintaining manageable analysis complexity through structured state classification.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If fault operation states are included in the Markov model, then the reliability assessment accuracy improves, but the device complexity increases due to multiple states and transition rates

Engineering Contradiction:
Improvereliability assessment accuracyVSAvoidmodel structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The Markov model is designed with universal applicability to switched reluctance motor systems with any number of phases. The model structure uses generalized state definitions where the number of phases can be varied, allowing the same fundamental model framework to assess reliability for different system configurations without requiring complete redesign, thus managing complexity while maintaining accuracy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If the system continues operation after unit failure, then the fault tolerance improves, but the reliability analysis difficulty increases due to multiple levels of faults

Engineering Contradiction:
Improvefault toleranceVSAvoidanalysis complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The Markov model dynamically captures the evolving system state through defined transition rates between normal operation, fault operation, and failure states. The model adapts to different fault scenarios by adjusting which transition rates are active, enabling accurate reliability assessment of systems with varying fault tolerance capabilities without requiring separate static models for each fault condition.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS10393811B2Quantitative evaluation method for reliability of Markov model switched reluctance motor system
Publication Date: 2019.08.27 CHINA UNIV OF MINING & TECH
  • US10393811B2 patent drawing
  • US10393811B2 patent drawing

AI summary

A quantitative evaluation method for the reliability of a Markov model switched reluctance motor system. The method comprises: solving a probability matrix P′T(t) of a switched reluctance motor system being in any survival state at any time t via a state conversion diagram of the switched reluctance motor system; calculating the sum of various elements of the probability matrix P′T(t) of the survival state, so that a reliability function R(t) is obtained; and thus calculating the average working time of the switched reluctance motor system before failure, thereby realizing the quantitative evaluation of the switched reluctance motor system and satisfying the requirements for the reliability analysis of a switched reluctance motor drive system. This disclosure has a good engineering application value.