BLDC Motor Speed Setpoint Control for Lower Power Consumption

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Solution Overview

Problem

Brushless direct current (BLDC) motors face challenges in optimizing electrical energy consumption to ensure they can respond promptly to user commands, particularly when the motor drives a load or is driven by it, leading to inefficient energy use.

Innovation Solution

A method and device that utilize a motor controller to detect commands, measure voltage, calculate and select speed setpoints, and adjust motor speed based on whether the motor drives or is driven by a load, reducing energy consumption by adapting to the actual voltage supplied and minimizing braking duration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the motor uses a fixed speed setpoint, then the control is simple, but the energy consumption cannot be optimized for different operating conditions

Engineering Contradiction:
Improveelectrical energy consumptionVSAvoidcontrol system complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent implements dynamic speed setpoint adjustment by detecting whether the motor is driving the load or being driven by it, and selecting between a first speed setpoint (when motor drives load) and a second speed setpoint (when load drives motor). This dynamic adaptation optimizes energy consumption for different operating conditions without requiring complex additional hardware

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system continuously monitors motor operation to detect the driving/driven state and adjusts the speed setpoint accordingly. This feedback mechanism enables the system to adapt to changing operating conditions and optimize energy consumption while maintaining simple control architecture

Inventive Principle:
Principle #23Feedback

2Speed

If the motor operates at high speed to respond quickly to commands, then the response time is reduced, but the energy consumption increases

Engineering Contradiction:
Improvemotor response speedVSAvoidelectrical energy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent changes the speed parameter dynamically based on operating conditions. When the motor drives the load, a first speed setpoint is used; when the load drives the motor, a second speed setpoint (higher than the first) is used. This parameter adjustment optimizes the balance between response time and energy consumption

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If the motor uses a single speed setpoint, then the control is simple, but the braking time and energy loss increase

Engineering Contradiction:
Improvebraking energy lossVSAvoidspeed control complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The system dynamically selects between two speed setpoints based on the operating mode. When the load drives the motor, the second speed setpoint is applied to reduce braking time and energy loss. This dynamic approach reduces energy waste during braking while maintaining simple control structure

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4170892B1Device and method for optimising the power consumption of a brushless DC motor
Publication Date: 2024.07.31 DELTA DORE SA
  • EP4170892B1 patent drawingFigure 1~2
  • EP4170892B1 patent drawingFigure 3
  • EP4170892B1 patent drawingFigure 4

AI summary

Method for optimizing the electrical energy consumption of a brushless DC motor, the motor being intended to drive a load up and down and being powered by an electrical supply. The method is executed by a motor controller and comprises: - detection of a command to start the motor, - measurement of the voltage delivered by the electrical supply, - calculation of a first and a second speed setpoint from the voltage measurement, the value of the second speed setpoint being greater than the value of the first speed setpoint, - detection if the motor is in a state in which the load drives the motor, - selection of the first speed setpoint if the motor is not in the state in which the load drives the motor, - selection of the second speed setpoint if the motor is in the state in which the load drives the motor.