Motor Drive Interface Circuit With MCU Isolation Architecture

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Solution Overview

Problem

Existing motor driving apparatuses face increased costs and installation space requirements due to the use of digital isolators for insulation, particularly in bidirectional signal transmission between the power circuit and control panel units.

Innovation Solution

Implementing a separate MCU in the power circuit unit to communicate with the control panel unit MCU, reducing the need for digital isolators by using mutual data communications for signal insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If digital isolators are used for insulation between power circuit unit and control panel unit, then insulation safety is improved, but cost and installation area increase

Engineering Contradiction:
Improveinsulation safetyVSAvoidcost and installation area
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the control system into two independent MCU units: a first MCU in the control panel unit and a second MCU in the power circuit unit. This segmentation allows each MCU to handle specific control tasks independently, reducing the need for extensive signal isolation between them and thereby reducing the number of digital isolators required.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a communication line as an intermediary medium between the two MCU units. This communication line enables data exchange while maintaining electrical isolation, replacing the need for multiple digital isolators and simplifying the overall insulation architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If bidirectional photocoupler is used for insulation, then signal insulation is improved, but cost and installation area increase

Engineering Contradiction:
Improvesignal insulationVSAvoidcost and installation area
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the insulation function from traditional digital isolators and implements it through the isolated communication architecture between the two MCUs. By taking out the insulation requirement from each individual signal line and implementing it at the system architecture level, the patent reduces the need for bidirectional photocouplers.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The communication line serves multiple functions: it enables bidirectional data communication between MCUs while simultaneously providing electrical isolation. This multi-functionality replaces what would traditionally require separate isolation components for each communication direction.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If terminal is provided for each additional device unit, then control capability is improved, but cost and volume increase

Engineering Contradiction:
Improvecontrol capabilityVSAvoidcost and volume
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The second MCU in the power circuit unit serves as a universal control interface for multiple additional device units. Instead of providing separate terminals for each device, the second MCU can control and monitor multiple devices through a unified communication interface, reducing the overall terminal count and system volume.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the control functions for multiple additional device units into a single second MCU. This consolidation allows multiple devices to be controlled through one integrated unit rather than requiring separate control terminals for each device, thereby reducing cost and volume.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3930183B1Interface circuit of motor driving apparatus
Publication Date: 2025.09.10 LS ELECTRIC CO LTD
  • EP3930183B1 patent drawingFigure 1
  • EP3930183B1 patent drawingFigure 2
  • EP3930183B1 patent drawingFigure 3

AI summary

The present invention relates to an interface circuit of a motor driving apparatus, the interface circuit comprising a power circuit unit for controlling driving of a motor, and a control panel unit which controls the power circuit unit and provides a user interface, wherein the power circuit unit further comprises a second MCU which controls a relay and an additional device unit and detects an operation state of the additional device unit, and the second MCU can communicate with a first MCU of the control panel unit via a communication line.