Motor Driver Identification Using Back-EMF and Winding Resistance

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Solution Overview

Problem

Existing motor driving systems lack the ability to detect whether the correct electric motor is connected to a motor driver controller, leading to potential underpowering or overpowering, which can cause damage to the motor and its load.

Innovation Solution

A motor driver controller configured to determine whether the correct electric motor is connected by measuring back electromotive force (EMF) voltage and winding resistance, using mappings to identify the correct motor, and dynamically adjusting settings to ensure safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor driver controller operates without motor identification, then the system is simpler and easier to operate, but the motor may be underpowered or overheated causing damage

Engineering Contradiction:
Improvemotor safetyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary motor identification by measuring back-EMF voltage and winding resistance before the motor operates. This preliminary action determines the motor type and configures appropriate control parameters, ensuring safe operation from the start without requiring complex real-time monitoring during operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The motor driver controller automatically identifies the connected motor type and configures its own control parameters without external intervention. The system measures electrical characteristics, compares them against stored profiles, and self-adjusts control settings, eliminating the need for manual configuration or complex external monitoring systems.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If the motor driver controller measures back-EMF voltage and winding resistance to identify the motor, then the motor type can be accurately detected, but the device complexity increases

Engineering Contradiction:
Improvemotor identification accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The motor driver controller uses its existing power electronics and control circuitry to perform multiple functions: driving the motor during operation and measuring back-EMF voltage and winding resistance during identification. The same microcontroller unit processes both control signals and measurement data, eliminating the need for separate dedicated measurement hardware.

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

Solution Approach 2:

The system identifies motor type by measuring electrical parameters (back-EMF voltage and winding resistance) that naturally vary with motor construction. By comparing these measured parameters against stored reference profiles, the system accurately identifies the motor type without requiring physical inspection or complex mechanical measurement apparatus.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the motor driver controller dynamically changes settings based on motor type, then the motor can operate safely, but the control system becomes more complex

Engineering Contradiction:
Improveoperational safetyVSAvoidcontrol simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The motor driver controller dynamically adjusts control parameters such as current limits, PWM frequency, and protection thresholds based on the identified motor type. The system automatically transitions between different operational modes and parameter sets, ensuring optimal and safe operation for each specific motor without requiring manual reconfiguration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system continuously monitors actual motor performance and compares it against expected characteristics for the identified motor type. If deviations are detected that could indicate unsafe operation, the controller adjusts parameters in real-time or triggers protection mechanisms, creating a closed-loop safety system that adapts to actual operating conditions.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Ensures safe operation of electric motors by preventing underpowering or overpowering, reducing the risk of motor damage and system downtime, and allowing for dynamic adjustment of settings based on the connected motor type.

Implementation Method 1

measure a back electromotive force voltage of the electric motor

Methodology Applied
Scientific EffectBack electromotive force (EMF): Electromagnetic Induction

Implementation Method 2

measure a winding resistance of the electric motor

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP3972123B1Motor driver controller analysis device
Publication Date: 2025.02.12 LENNOX IND INC
  • EP3972123B1 patent drawingFigure 1
  • EP3972123B1 patent drawingFigure 2
  • EP3972123B1 patent drawingFigure 3~4

AI summary

A motor driving system (100) includes motor driving circuitry (108) configured to operate an electric motor (102). The system (100) further includes a controller (104) that is configured to send a signal to energize the electric motor (102) and to measure a back electromotive force voltage of the electric motor (102). The controller (104) is further configured to determine a temperature value based on the measured back electromotive force voltage using a back electromotive force voltage mapping that maps back electromotive force voltages to temperature values. The controller (104) is further configured to determine an expected winding resistance value based on the determined temperature value using a resistance mapping that maps winding resistance values to temperature values. The controller (104) is further configured to measure a winding resistance of the electric motor (102), to compare the measured winding resistance of the electric motor to the expected winding resistance value, and to output a match result indication based on the comparison.