Robotic Drive EMI Filtering With Phase-Shift Switching
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Solution Overview
Problem
Electromagnetic interference (EMI) and leakage current are significant issues in robotic devices with distributed motor drives, particularly those using high switching devices like Si COOLMOS, GaN, and SiC, which complicate system reliability and safety, and traditional EMI filters increase cost, weight, and reduce payload capability.
Innovation Solution
A robotic device with a controller for phase-shift switching and an EMI filter comprising small split common mode chokes and bus filters positioned between the rectifier and axes, along with synchronized clock control, to reduce EMI noise and suppress leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If big multi-stage EMI filters are used to reduce EMI noise, then EMI noise is reduced, but cost, weight, and space increase
Solution Approach 1:
The patent divides the EMI filtering function into multiple small split common mode chokes, each associated with a different axis, rather than using a single large multi-stage filter. This segmentation approach reduces the weight and space requirements while maintaining effective EMI noise reduction across all axes of the robotic device.
2Object-affected harmful factors
If big multi-stage EMI filters are used to reduce EMI noise, then EMI noise is reduced, but cost, weight, and space increase
Solution Approach 1:
The patent distributes EMI filtering components across multiple axes as small split common mode chokes, significantly reducing the space required compared to a centralized big multi-stage filter. This allows the robotic device to maintain EMI protection while preserving payload capability and reducing overall device footprint.
3Power
If high switching devices are used to improve power density and efficiency, then power density and efficiency improve, but EMI noise increases
Solution Approach 1:
The patent applies local EMI filtering quality by placing small split common mode chokes at specific locations near each motor drive axis, rather than using a single distant filter. This localized approach effectively suppresses EMI noise generated by high switching devices while maintaining the power density and efficiency benefits of modern switching components.
4Object-affected harmful factors
If EMI filters are added to reduce EMI noise, then EMI noise is reduced, but leakage current increases
Solution Approach 1:
The patent uses small split common mode chokes that provide EMI filtering while maintaining better leakage current characteristics compared to traditional large EMI filters. The segmented architecture allows for optimized filtering performance with reduced parasitic effects that cause leakage current.
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 reduces EMI noise and leakage current, enhancing system reliability and safety while minimizing weight and cost, and maintaining payload capacity.
Implementation Method 1
the EMI filter is configured to further reduce the EMI noise and suppress the leakage current from the plurality of axes
Implementation Method 2
the EMI filter comprises a plurality of small split common mode chokes
Data Source
AI summary
A robotic device for reducing electromagnetic interference (EMI) noise and suppress leakage current is provided. The robotic device comprises a controller configured to control phase-shift switching of a plurality of axes to reduce electromagnetic interference (EMI) noise and suppress leakage current, an electrical circuit, and a plurality of loads coupled to a plurality of motors of the plurality of axes. The electrical circuit comprises a power source and rectifier; an EMI filter configured to further reduce the EMI noise and suppress the leakage current from the plurality of axes; and the plurality of axes comprising a plurality of drives and a plurality of motors that are configured to operate the plurality of loads.