Brushless Motor Pre-Comm Angle Modulation

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Solution Overview

Problem

Existing methods for operating electronically commutated electric motors, such as brushless DC motors, face challenges in achieving optimal efficiency and adapting to changing operating conditions like temperature and wear, especially when operating at maximum power and voltage limits, due to inefficiencies in pre-commutation angle regulation.

Innovation Solution

A method that modulates a periodic, harmonic signal onto the pre-commutation angle and multiplies it by a state parameter like current consumption, using a control device with a signal generator and sensor units to determine an adapted pre-commutation angle through phase-shifting and integration, ensuring optimal operation and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the pre-commutation angle is regulated to achieve optimal operating point, then motor efficiency is improved, but the system complexity increases due to additional control device and signal processing requirements

Engineering Contradiction:
Improvemotor efficiencyVSAvoidcontrol device complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The control device continuously monitors the motor's operating state by detecting current consumption and uses this feedback to dynamically adjust the pre-commutation angle. The periodic signal modulation and correlation analysis create a closed-loop feedback system that automatically optimizes efficiency without manual intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The motor control system performs self-optimization by automatically detecting its own operating state and adjusting its pre-commutation angle without external control. The system uses its own current consumption signals to generate the optimization feedback, making the control process autonomous.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If the pre-commutation angle is fixed, then the control system is simple, but the motor cannot adapt to changing operating conditions like temperature and wear

Engineering Contradiction:
Improveadaptation to operating conditionsVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pre-commutation angle transitions from a static fixed value to a dynamic parameter that continuously adapts to changing operating conditions. The control device modulates the pre-commutation angle based on real-time detection of motor state, enabling the system to respond to temperature changes, wear, and load variations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system optimizes motor performance by dynamically changing the pre-commutation angle parameter based on detected operating conditions. The control device adjusts this electrical parameter in response to variations in motor temperature, wear state, and load, allowing the motor to maintain optimal efficiency across different operating scenarios.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If signal processing with multiplication and integration is performed, then precise pre-commutation angle determination is achieved, but the processing time and computational load increase

Engineering Contradiction:
Improvepre-commutation angle precisionVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The control device uses periodic signal modulation at predetermined frequencies to analyze motor operating state. By modulating the pre-commutation angle with a periodic signal and analyzing the correlated current consumption signals at the same frequency, the system efficiently extracts precise angle information through frequency-domain analysis rather than continuous time-domain processing.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3673576B1Method and apparatus for operating an electronically commutated electric motor
Publication Date: 2022.01.26 ROBERT BOSCH GMBH
  • EP3673576B1 patent drawingFigure 1

AI summary

The invention relates to a method for operating an electronically commutated electric motor (10), in which method, during ongoing operation of the electric motor (10), in order to achieve an optimal operating point of the electric motor (10), a pre-commutation angle (14) provided by a control device (12) is regulated. According to the invention, during an operation of the electric motor (10), a period signal (16) is modulated to the pre-commutation angle (14) and a state parameter (18) of the electric motor (10) correlating with an efficiency of the electric motor (10) is detected.