Rockwell Automation Technologies Incorporated

Omid Shirazi

Patrick E Ozimek

Nandini Ganesan

A system and method for varying an amplitude of voltage on a DC bus by track segment in a linear drive system for an independent cart system according to application requirements is disclosed. The track includes at least a first portion and a second portion, where a DC voltage at a first amplitude is provided to the first portion of the track, and a DC voltage at a second amplitude is provided to the second portion of the track. The first amplitude of the DC voltage is selected to permit movers traveling along the track to travel at full rated speed with a full rated three applied to the mover. The second amplitude of the DC voltage is selected to permit the movers to travel at a reduced speed with full or increased three applied or to travel at full rated speed with a reduced force applied to the mover.

Variable DC bus voltage in an independent cart system

Sections of a linear motor track can each include a single power sensor configured to detect a power current in an erroneous state and one or more reference sensors configured to detect reference currents in erroneous states. The power sensor can be arranged between multiple drive coils of a section and a DC power rail (or 'mid-bus') for the drive coils. The power sensor can produce a single isolated output to a processor for the section, and the processor, in turn, can compare the output to a threshold for determining an error. The one or more reference sensors can be arranged between lower switches and a DC-reference bus, thereby providing a DC-referenced sensing signal for the drive coil currents. By referencing the processor to the same rail as the DC-referenced current sensing circuit, the reference sensors can produce outputs to the processor without any need for isolation.

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Brown Deer, WI, United States of America

Omid Shirazi