Considerations on transmission of information and power utilizing power feed line for inverter drive system: two-way communication system

摘要

Power feed line for AC motor drive systems utilizing PWM inverter has a characteristic as a distributed constant line, because the inverter is connected to the motor using long leads. Therefore quality of power deteriorates, e.g. the resonance of harmonics and reflection at the motor terminals, in inverter-fed ac motor drive systems. The operation in the desired rotating speed range is impossible and significant over voltages happens. This present paper deals with the transmission system that can able to transmit information signal on leads with power at the same time. Direct-sequence spread-spectrum (DSSS) communication system is selected as a transmission system. The DSSS communication system has superior resistance to noise and it can realize spread-spectrum multiple access (SSMA) communication system that is kind of a code division multiple access (CDMA) communication system. The results of experiments can be summarized as follows: (1) A simple structure signal transmitting and receiving circuit is developed; (2) Two-way communication system is established.