Microcomputer Synchronization for Motor Drive Timing

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Solution Overview

Problem

Existing motor control systems with multiple microcomputers face challenges in synchronizing operation stop timing due to voltage differences and production tolerances between clock generation circuits, leading to potential motor torque pulsation and erroneous failure determinations.

Innovation Solution

The implementation of a synchronization signal transmission and correction mechanism between microcomputers, where a timing determiner in one microcomputer determines the normality of the synchronization signal, allowing for synchronized drive timing or asynchronous operation to prevent failure propagation and maintain motor assist functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple microcomputers operate independently with their own clock generation circuits, then system reliability is improved through redundancy, but drive timing synchronization deteriorates due to voltage differences and production tolerances

Engineering Contradiction:

Improvesystem reliabilityVSAvoiddrive timing synchronization

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

A synchronization signal transmission mechanism is introduced as an intermediary between microcomputers. The timing determiner in each microcomputer receives synchronization signals from others and adjusts its drive timing accordingly, mediating the timing differences caused by independent clock generation circuits while maintaining system redundancy

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The timing determiner continuously monitors synchronization signals from other microcomputers and adjusts drive timing based on the received timing information. This feedback mechanism ensures that despite production tolerances and voltage differences, all microcomputers maintain synchronized drive timing

Inventive Principle:

Principle #23Feedback

2Ease of operation

If microcomputers stop operation independently based on their own voltage conditions, then ease of operation is improved, but motor torque pulsation worsens due to asynchronous stop timing

Engineering Contradiction:

Improveoperation stop controlVSAvoidmotor torque pulsation

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The stop determination signal acts as an intermediary communication mechanism between microcomputers. Each microcomputer transmits its stop determination status to others, allowing coordinated stop timing that prevents motor torque pulsation while maintaining operational simplicity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Microcomputers continuously exchange stop determination signals and receive timing information from other microcomputers. This feedback ensures that when one microcomputer determines to stop, others follow suit at the appropriate timing, preventing asynchronous stop and resulting torque pulsation

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If synchronization signal transmission is added between microcomputers, then drive timing synchronization is improved, but device complexity worsens

Engineering Contradiction:

Improvedrive timing synchronizationVSAvoidsynchronization mechanism complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The communication interface between microcomputers is designed to serve multiple functions: normal operational communication, synchronization signal transmission, and stop determination signal exchange. This multi-functionality reduces the need for dedicated synchronization hardware, thereby limiting the increase in device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If microcomputers operate asynchronously to avoid failure propagation, then reliability is improved, but motor control precision deteriorates due to timing differences

Engineering Contradiction:

Improvefailure isolationVSAvoidmotor control precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts its operation mode based on synchronization status. When synchronization signals are received normally, microcomputers operate in synchronized mode for precise motor control. When synchronization fails, the system transitions to asynchronous operation to isolate failures, accepting reduced precision as a trade-off for reliability

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10668945B2Motor control apparatus, motor drive system, and motor control method

Publication Date: 2020.06.02 DENSO CORP

AI summary

A motor control apparatus includes: multiple motor drive circuits that drive at least one motor; and multiple microcomputers that are operated by a microcomputer power source and include a drive signal generator that generates a motor drive signal. The microcomputers include at least one microcomputer including a stop determiner that determines that operation of an own microcomputer is about to be stopped and transmits information as a stop determination signal. A microcomputer having received the stop determination signal from at least one different microcomputer actually stops operation of an own microcomputer.