Converter Control Loop Tuning With ML-Based PID Adjustment

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Solution Overview

Problem

Traditional PID controller tuning methods, especially in digital control systems for electrical drives, often result in reduced stability margins due to neglecting sampling effects, and require experienced personnel for manual tuning, which is time-consuming and inefficient for systems with long loop times.

Innovation Solution

A method utilizing machine learning models to acquire actual values from drive systems and infer adjustments for control parameters, such as proportional gain and integral time, to improve control accuracy and stability, automatically optimizing control loops based on actual rotation speed, torque, and control differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional PID controller tuning methods are used in digital control systems, then the control loop can be implemented, but stability margins are reduced due to neglecting sampling effects

Engineering Contradiction:
Improvestability marginVSAvoidcontrol accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent transforms continuous-time PID parameters (Kp, Ki, Kd) into discrete-time parameters (Kp_s, Ki_s, Kd_s) by applying sampling period compensation formulas. This parameter transformation accounts for sampling effects while maintaining control accuracy, resolving the contradiction between stability and precision in digital implementations.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If manual tuning methods are used for control parameters, then experienced personnel can optimize the control loop, but the process is time-consuming particularly for systems with long loop times

Engineering Contradiction:
Improvecontrol accuracyVSAvoidtuning time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent enables the control system to automatically determine optimal PID parameters based on measured process characteristics (rise time, settling time, overshoot) without requiring external expert intervention. The system self-adjusts by calculating parameters from its own operational data, eliminating time-consuming manual tuning while maintaining optimal control accuracy.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If control parameters are fixed during operation, then the control loop is simple to operate, but the system cannot adapt to wear or environmental changes

Engineering Contradiction:
Improveoperational simplicityVSAvoidadaptability to changes
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent transforms static PID parameters into dynamic parameters that automatically adjust based on real-time process characteristics. The system continuously monitors performance metrics and recalculates optimal parameters, enabling adaptation to wear and environmental changes while maintaining ease of operation through automated adjustment.

Inventive Principle:
Principle #15Dynamics

4Loss of time

If automated tuning methods are implemented, then tuning time is reduced, but device complexity increases

Engineering Contradiction:
Improvetuning timeVSAvoidcontrol system complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent introduces measurement intermediaries (timers and detectors) that automatically capture process characteristics (rise time, settling time, overshoot) and feed them to parameter calculation units. This intermediary measurement system enables automated tuning without requiring complex artificial intelligence, balancing reduced tuning time with manageable system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS20230266718A1Control loop optimization
Publication Date: 2023.08.24 SIEMENS AG
  • US20230266718A1 patent drawing
  • US20230266718A1 patent drawing
  • US20230266718A1 patent drawing

AI summary

A method of optimizing a control loop of a converter, such as a control system of the converter, includes acquiring actual values of a drive system powered by the converter, inferring, based on at least one machine learning model and the actual values, one or more adjustments of control parameters of the control loop for improving the control accuracy, and outputting the one or more adjustments for adapting control parameter values.