Brushless Motor Drive Circuit With Induced Current Discharge

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Solution Overview

Problem

Conventional brushless motors experience a long turn-off response time, high power consumption, and inability to quickly stop vibration in electronic devices due to the slow dissipation of energy after power is cut off.

Innovation Solution

A drive control apparatus for brushless motors, comprising a motor drive circuit and a discharge circuit, where the motor drive circuit stops supplying power to the brushless motor during the turn-off period and outputs the induced current to the discharge circuit, which consumes the electric energy to quickly turn off the motor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the motor drive circuit stops supplying power to the brushless motor during turn-off period, then power consumption is reduced, but the induced current generated by the motor cannot be consumed quickly enough

Engineering Contradiction:
Improvepower consumptionVSAvoidturn-off response time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The patent introduces a discharge circuit as an intermediary component to handle the induced current from the brushless motor during turn-off. The discharge circuit includes a discharge switch and discharge resistor that provide a dedicated path for current dissipation, separating the power supply function from the energy dissipation function. This allows the motor drive circuit to stop supplying power while the discharge circuit efficiently consumes the generated induced current, resolving the contradiction between reducing power consumption and shortening turn-off response time.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the power management system into distinct functional modules: the motor drive circuit for power supply during operation, and the discharge circuit for energy dissipation during turn-off. By dividing the system into these separate segments with specialized functions, the patent enables independent optimization of each module - the drive circuit can fully disconnect to minimize power consumption while the discharge circuit handles current dissipation to reduce turn-off time.

Inventive Principle:
Principle #1Segmentation

2Loss of time

If the brushless motor is controlled to stop vibration quickly, then the turn-off response time is reduced, but the energy dissipation becomes insufficient without a dedicated discharge path

Engineering Contradiction:
Improveturn-off response timeVSAvoidenergy dissipation
Core Design Contradiction:
Loss of timeVSLoss of energy

Solution Approach 1:

The discharge circuit acts as an intermediary energy dissipation system that activates during motor turn-off. When the motor drive circuit stops supplying power, the discharge switch closes to connect the motor windings to the discharge resistor, creating a dedicated energy dissipation path. This intermediary system ensures that the induced current is efficiently consumed, enabling quick turn-off response while maintaining adequate energy dissipation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful induced current (which causes extended turn-off time and energy loss) into a beneficial dissipation process. By providing the discharge circuit with controlled resistance, the induced current is transformed into useful heat energy in the discharge resistor, quickly eliminating the residual energy from the motor windings and achieving fast turn-off response.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The proposed solution significantly reduces the duration required to completely turn off the brushless motor, achieving quick shutdown and minimizing power consumption.

Implementation Method 1

The discharge circuit is configured to: in the turn-off period of the brushless motor, receive the induced current, and apply work by using the induced current, to consume electric energy of the brushless motor

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The motor drive circuit is configured to: in a turn-off period of the brushless motor, stop supplying power to the brushless motor, and output an induced current generated by the brushless motor to the discharge circuit

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4187773B1Drive control device for brushless motor and related device
Publication Date: 2025.02.12 HONOR DEVICE CO LTD
  • EP4187773B1 patent drawingFigure 1a
  • EP4187773B1 patent drawingFigure 1b
  • EP4187773B1 patent drawingFigure 1c

AI summary

This application relates to the field of drive control technologies, and discloses a drive control apparatus for a brushless motor and a related device, to quickly turn off a brushless motor. A specific solution is as follows: A motor drive circuit is connected to a brushless motor, and a discharge circuit is connected to the brushless motor and the motor drive circuit. The motor drive circuit is configured to: in a turn-off period of the brushless motor, stop supplying power to the brushless motor, and output an induced current generated by the brushless motor to the discharge circuit. The discharge circuit is configured to: in the turn-off period of the brushless motor, receive the induced current, and apply work by using the induced current, to consume electric energy of the brushless motor, and accelerate turn-off of the brushless motor.