Secure Data Communication through Power Electronic Converters in a DC Microgrid

This research focuses on establishing a secure data communication system among power electronic converters connected to a common voltage bus in a dc microgrid. As a proof-of-concept, a buck and two boost dc-dc converters, sharing a 24 V dc bus, have been used for simulation in Matlab (R) Simulink (R). Digital bits are generated at 10 kbps rate at the three converters which are modulated by frequency shift-keying (FSK) algorithm using three different frequency bands with two distinct frequencies to represent bits '0' and '1'. Active band-pass filters are used to accurately extract useful data signal from the dc voltage waveform for the three communication channels having different frequency bands. A chaotic dynamic system is adopted for each power converter to encrypt and decrypt the data stream. The encrypted data in the communication channel is secure unless the attacker can perfectly synchronize with the chaotic dynamic system, which is very unlikely Data in various frequency bands can be simultaneously demodulated and decrypted at the receiver with very good accuracy. The simulation result suggests that the bit-error-ratio (BER) is less than 0.01% even during system transients such as load change and/or due to transition between on-off states of other power converter(s).