Multiplexed Optical Link for Gating Pulse Transmission in Multilevel Converters

Abstract

Multilevel power converters play an increasingly important role in energy transmission, high-power electric drives and renewable energy systems. The transmission of control signals for the semiconductor switches in power converters is critical for the operation of the system, and therefore optical communications links are employed to minimize electromagnetic interference. However, conventional parallel communication topologies have the drawback of requiring a high number of independent optical fibers and transmitter-receiver pairs as the number of transmitted signals increase, which limits the flexibility and scalability of the link. In this paper we propose the design of an optical link with wavelength division multiplexing (WDM) based on a digital micromirror device (DMD) and a linear detector array as receiver. The main advantages of the proposed system are the high flexibility and scalability of the communications link. Simulation results are obtained from a mathematical modeling of the transmitter, the link and the receiver. The communication is established by means of an asynchronous protocol in order to ensure the correct decoding of the transmitted gating signals. A feasibility analysis of the optical link is carried out in terms of the waveform quality of the multilevel inverter output voltage, measured by its total harmonic distortion (THD). The simulation results obtained in MATLAB/Simulink environment validate the methodology to enable a future implementation of the proposed optical communication link.