Decoupled Control Loops for Electric Machine Regulation

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Solution Overview

Problem

Existing control systems for electric machines struggle to decouple the adjustment of setpoints from disturbance variable compensation, leading to interdependent and inefficient control processes that affect the smooth operation and torque distribution in electrical drive systems.

Innovation Solution

A control device with two decoupled control loops is implemented, where one loop compensates for disturbance variables and the other sets desired operating points, using a first manipulated variable to calculate and subtract its influence from the actual operating variable, allowing independent modular control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single control device is used to both set the operating point and compensate disturbance variables, then the control structure is simple, but the control loops become interdependent and cannot operate independently

Engineering Contradiction:
Improvecontrol structureVSAvoidindependence of control loops
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The control device is segmented into a first control device for disturbance variable compensation and a second control device for operating point setting. This segmentation allows each control loop to operate independently while maintaining overall system functionality, resolving the contradiction between structural simplicity and operational independence.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The disturbance variable compensation function is extracted from the operating point setting control loop. By taking out the disturbance compensation functionality into a separate first control device, the second control device can focus solely on operating point setting without interference, achieving independent control loops.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If disturbance variable compensation is implemented, then torque ripple and harmonics are reduced, but the control process becomes more complex and interdependent

Engineering Contradiction:
Improvetorque ripple reductionVSAvoidcontrol process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control process is segmented into independent modules: disturbance detection, disturbance variable compensation calculation, and operating point setting. This modular segmentation achieves torque ripple reduction while keeping each module's complexity manageable and independent.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An intermediary computing device calculates the change in operating point resulting from disturbance variable compensation. This intermediary component provides the necessary decoupling information that allows disturbance compensation to improve torque quality without creating complex interdependencies in the control process.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the second control device uses the actual operating point value including disturbance compensation, then the control is integrated, but the disturbance compensation influences the operating point setting and vice versa

Engineering Contradiction:
Improvecontrol integrationVSAvoidindependence of control functions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The influence of disturbance variable compensation on the operating point is extracted and calculated separately by the computing device. The second control device then uses this extracted information to determine the manipulated variable based on the original operating point deviation, not the compensated value, maintaining functional independence.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The computing device creates a copy or model of the operating point change that would result from disturbance compensation. This copied information is then used by the second control device to make adjustments without being directly influenced by the actual disturbed operating point, preserving control independence.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3593448B1Regulating device for an electric machine, electric drive system, and method for regulating an electric machine
Publication Date: 2021.04.07 ROBERT BOSCH GMBH
  • EP3593448B1 patent drawingFigure 1~2

AI summary

The invention relates to the regulation of an electric machine, wherein an interference variable is compensated for and simultaneously a target value is set. In the process, two mutually independent control loops are provided. A first control loop is used to compensate for the interference variable, and a second control loop is used to set a specified target value. When the specified target value is being regulated, the control loop is decoupled from the interference variable compensation process. In this manner, a modular independent regulation can be achieved for the target value and the interference variable compensation process.