Power and signal dual modulation‐based bidirectional communication between intrinsically safe converters

Abstract

Abstract In harsh operating environments such as mines and gas stations, intrinsically safe power converters are required for electronics devices. Reliable communication is the key ensuring good performance of monitoring and coordinated control for intrinsically safe converters. This paper proposes a power and signal dual modulation (PSDM)‐based communication method for intrinsically safe parallel‐connected Buck converters. The bidirectional communication between two parallel Buck converters is realized by combining the frequency shift keying (FSK) and phase shift keying (PSK) methods. In addition, switching frequencies are employed to identify the signals received from the power converters interfacing different sources. According to the intrinsic safety requirement, inductors and capacitors are redesigned based on the modulated voltage ripples during communication. Simulations and prototype experiments are performed to verify the feasibility of the proposed bidirectional communication for intrinsically safe converters. The amplitude of voltage ripples modulated for carrying data is restricted to less than 1.5% of the bus voltage. The transmission speed can be achieved from 0.5 to 2kbps depending on the adopted switching frequencies. The demodulation delay is less than 5% duration of one bit of transmitted data.

Keywords

• frequency modulation
• phase modulation
• power convertors