Motor cable communication concept based on DSSS for inverter‐fed electric drives

Abstract

Nowadays, electric motors and frequency converters have a great variety of applications. In motor feedback systems, communication is performed over separate sensor cables, which are notable for their high cost. Power line communication (PLC) over the motor cable is a promising and cost effective alternative. In this paper, a communication concept based on PLC and direct sequence spread spectrum (DSSS) channel access method is presented for motor cable communication. The channel characteristics and noise in the channel of a laboratory test setup are studied. Effect of the frequency converter output and switching frequencies on the channel noise are investigated. Capacitive and inductive signal coupling methods are evaluated and compared first theoretically by measurements and analysis of channel characteristics, and then practically by data transmission tests carried out in the laboratory test setup. Software-defined radios (SDRs) are used as the data transmission devices for the communication concept evaluation. Concept's performance against variation of a signal-to-noise ratio (SNR) and switching frequency of the converter are evaluated. The concept applicability limits and optimal settings are presented. It can be stated that the concept provides a wider application range, than available solutions and can be effective for motor monitoring and speed data transmission.

Overview of Talkative Power Conversion Technologies

“…As early as 2010, many studies on PLC in inverter-fed motor systems have been carried out, and most of them developed communication and energy harvesting on motor cable via coupling interface and PLC modem [51], [52]. In this system, high-bit-rate communication relies on high-frequency sinusoidal carriers injected into the cable, which leads to high-frequency noise and torque ripples.…”