Current Observer Control for AC Motor Noise Rejection

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Solution Overview

Problem

Current methods in controlling vehicle motors introduce noise in the voltage signal, leading to disturbances, which is undesirable.

Innovation Solution

A method and system that predicts phase current and disturbance voltage for a second phase cycle, calculates damping and disturbance voltage corrections, and applies a delay to the final voltage at the inverter to minimize noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current methods are used to control the motor, then the motor can be operated, but noise is introduced in the voltage signal causing disturbances

Engineering Contradiction:

Improvemotor operation stabilityVSAvoidnoise in voltage signal

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback control by measuring the actual phase current, comparing it with the predicted observed phase current, and using the difference to calculate disturbance voltage corrections. This closed-loop feedback mechanism continuously adjusts the voltage signal to reject disturbances and eliminate noise, thereby improving motor operation stability while reducing harmful voltage signal noise.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces a current observer as an intermediary component that predicts the expected phase current based on the motor model and control inputs. This intermediary prediction is then compared with actual measurements to extract disturbance information, allowing the system to identify and compensate for noise without directly measuring it, thus improving reliability while filtering out harmful factors.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If disturbance rejection is enhanced, then noise immunity is improved, but system complexity increases due to additional control modules

Engineering Contradiction:

Improvenoise immunityVSAvoidcontrol system structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent integrates multiple functions into unified control modules. The current observer simultaneously performs current prediction, disturbance estimation, and noise identification. The disturbance rejection module combines both damping voltage correction and disturbance voltage correction in a single integrated control loop. This multi-functionality approach enhances noise immunity while minimizing the increase in system complexity by avoiding redundant separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12506431B2Enhanced disturbance rejection with noise immunity in a current controlled alternating current machine with use of current observer

Publication Date: 2025.12.23 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A system and method of operating a vehicle. The system includes an inverter, a motor, and a sensor for measuring a phase current between the inverter and the motor in a first phase cycle in which the inverter is operated at a first voltage. A processor predicts an observed phase current and a raw disturbance voltage for the second phase cycle from the phase current, calculates a damping voltage correction for the second phase cycle from the observed phase current and a disturbance voltage correction for the second phase cycle from the raw disturbance voltage, calculates a final voltage in the second phase cycle from a core current regulator voltage, the damping voltage correction and the disturbance voltage correction, calculates a second voltage in the first phase cycle by applying a delay to the final voltage in the second phase cycle; and applies the second voltage at the inverter.