DC Power Supply Inductor Sizing for Servo Current Fluctuation

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Solution Overview

Problem

Existing DC power supply systems face challenges in suppressing sneak current fluctuations and device size increase due to the provision of low pass filters in each DC device, particularly in systems with servo devices and electric motors.

Innovation Solution

A design assistance device and method that calculates an appropriate inductance value for an inductor to be placed in the power supply path, using configuration information and current source models to suppress current fluctuations without the need for filters in individual servo devices, allowing for downsizing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a low pass filter is provided in each DC device to suppress transient voltage, then voltage fluctuation is suppressed, but the device size increases

Engineering Contradiction:
Improvevoltage fluctuation suppressionVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent consolidates the filtering function from individual device-level low pass filters into a single system-level low pass filter located in the power supply line. This merging approach maintains voltage fluctuation suppression capability while eliminating the need for multiple distributed filters, thereby reducing overall device size and complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a low pass filter as an intermediary component in the power supply line between the DC power supply and the DC devices. This intermediary filter suppresses transient voltage fluctuations at the source before they reach the devices, replacing the need for individual filters in each device and thus reducing device size.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If low pass filters are provided in each servo device to suppress sneak current fluctuation, then current fluctuation is suppressed, but the servo device size increases

Engineering Contradiction:
Improvecurrent fluctuation suppressionVSAvoidservo device size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the current fluctuation suppression function from multiple individual servo devices into a single low pass filter placed in the common power supply line. This system-level filtering approach suppresses sneak current fluctuations affecting all devices without requiring each servo device to contain its own filter, thereby enabling downsizing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The low pass filter acts as an intermediary in the power supply path, mediating the transient current fluctuations generated by servo devices before they propagate through the system. This centralized filtering approach suppresses current fluctuations effectively while avoiding the need for distributed filters in each device.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If individual filters are installed in each DC device, then transient voltage suppression is improved, but system complexity increases

Engineering Contradiction:
Improvetransient voltage suppressionVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple individual filtering functions into a single unified low pass filter in the power supply line. This consolidation reduces system complexity by eliminating the need for multiple distributed filters and their associated configurations, while maintaining effective transient voltage suppression across all DC devices.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If low pass filters are provided in each servo device, then sneak current fluctuation is suppressed, but device complexity increases

Engineering Contradiction:
Improvesneak current fluctuation suppressionVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the sneak current fluctuation suppression function into a single low pass filter in the power supply line, eliminating the need for individual filters in each servo device. This consolidation reduces device complexity while maintaining effective suppression of sneak current fluctuations across the entire system.

Inventive Principle:
Principle #5Merging (Combining)

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 solution effectively suppresses sneak current fluctuations and reduces the size of servo devices by optimizing inductance values based on system configuration, thereby enhancing the efficiency and compactness of DC power supply systems.

Implementation Method 1

an inductor connected to the power supply path, and includes: an acquisition unit configured to acquire configuration information... and an output unit configured to output an inductance value of the inductor

Methodology Applied
Scientific EffectInductance: Inductor

Data Source

PatentEP4660871A1Design assistance device, design assistance method, and design assistance program
Publication Date: 2025.12.10 OMRON CORP
  • EP4660871A1 patent drawingFigure 1
  • EP4660871A1 patent drawingFigure 2
  • EP4660871A1 patent drawingFigure 3

AI summary

A design assistance device for assisting design of a DC power supply system including a first system including a plurality of servo devices each including an inverter circuit and an electric motor; a power supply path configured to supply DC power from a DC power supply to the plurality of servo devices; a second system to which the DC power is supplied; and an inductor connected to the power supply path acquires configuration information including connection configuration information of the power supply path and the plurality of servo devices, information regarding the number of axes of the servo device, wiring information connecting the DC power supply, the plurality of servo devices, and the second system, and characteristic information of the servo devices, and outputs an inductance value of the inductor, based on the configuration information, the inductance value suppressing a fluctuation in a current flowing through the second system.