H-Bridge Motor Control During Instantaneous Power Interruptions

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Solution Overview

Problem

Existing electronic apparatuses with DC motors powered by AC sources face shutdowns due to voltage drops during AC instantaneous interruptions, as existing solutions like Japanese Patent Laid-Open No. 2012-39847 reduce motor rotation speed rather than maintaining normal operation.

Innovation Solution

An electronic apparatus with a DC motor, a detection circuit, an H bridge circuit, and a switching control circuit that sets upper arm switches to off and lower arm switches to on during power source interruptions, reducing power consumption and regenerating motor current with minimal loss to maintain operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If servo control is performed to compensate for torque fall during AC instantaneous interruption, then motor torque is maintained, but power source voltage further falls causing shutdown

Engineering Contradiction:

Improvemotor torqueVSAvoidpower source voltage

Core Design Contradiction:

ForceVSPower

Solution Approach 1:

Instead of trying to maintain motor operation during AC instantaneous interruption (which causes voltage collapse), the invention inverts the approach by intentionally stopping the motor during the interruption. This allows the power source voltage to recover and prevents system shutdown, enabling faster resumption of operation after the interruption ends.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention converts the harmful effect of motor torque demand during voltage drop into a beneficial outcome by deliberately allowing the motor to stop. This temporary cessation prevents the vicious cycle of voltage collapse, and the system benefits from faster voltage recovery and quicker resumption of normal operation compared to continuous torque maintenance attempts.

Inventive Principle:

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

2Duration of action of stationary object

If position command is changed to avoid motor stop during AC instantaneous interruption, then motor operation continuity is maintained, but rotation speed is reduced preventing normal operation

Engineering Contradiction:

Improvemotor operation continuityVSAvoidmotor rotation speed

Core Design Contradiction:

Duration of action of stationary objectVSSpeed

Solution Approach 1:

The invention applies periodic action by implementing a control strategy that alternates between motor operation and intentional stopping based on power source voltage conditions. During AC instantaneous interruption when voltage drops, the motor is stopped; when voltage recovers, normal operation resumes. This periodic on-off control based on voltage conditions optimizes both operation continuity and rotation speed maintenance.

Inventive Principle:

Principle #19Periodic action

3Power

If motor drive voltage is maintained during AC instantaneous interruption, then torque compensation is achieved, but power source voltage collapse occurs causing system shutdown

Engineering Contradiction:

Improvemotor drive voltageVSAvoidsystem shutdown prevention

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The invention applies beforehand cushioning by detecting AC instantaneous interruption in advance and proactively stopping the motor before power source voltage collapse occurs. This preventive measure cushions against the potential harm of voltage collapse and system shutdown, allowing the power source to recover voltage levels without the burden of motor torque demand.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

This solution allows for continued normal motor operation during AC instantaneous interruptions by efficiently managing power source voltage drops and regenerating motor energy, reducing speed reduction and preventing shutdowns.

Implementation Method 1

a DC motor that is driven based on a current supplied from a power source

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a detection circuit that detects an instantaneous interruption of the power source

Methodology Applied

Scientific EffectVoltage detection: Electric Field

Data Source

PatentUS11929701B2Electronic apparatus, control method of electronic apparatus and storage medium

Publication Date: 2024.03.12 CANON KK

AI summary

The electronic apparatus including a DC motor that is driven based on a current supplied from a power source, and including: a detection circuit that detects an instantaneous interruption of the power source; an H bridge circuit having an upper arm circuit having two switching elements connected in parallel to the power source and a lower arm circuit having two switching elements connected in parallel to a ground, the upper arm circuit and the lower arm circuit being connected in series, and controlling a current to be supplied to the DC motor; and a switching control circuit that controls the switching element, and in a case where an instantaneous interruption of the power source is detected by the detection circuit, the switching control circuit sets the switching elements of the upper arm circuit to off and sets the switching elements of the lower arm circuit to on.