Adaptive Fault-Tolerant Communication Based-Control for Parallel Connected Rectifiers

Abstract

This article proposes an adaptive and fault-tolerant communication method for controlling parallel-connected active front-end rectifiers (AFRs). The proposed method relies on the principle of masterslave communication based on the controller area network bus protocol. The master unit is responsible for generating current reference signal and for sharing it with the slaves, while the slave units are solely responsible for generating the power based on the received reference set points. The master can be selected and changed automatically based on a negotiation algorithm among the connected rectifiers. Then, if a communication fault occurs in the master, another master is chosen by the slaves. On the other hand, slaves' communication faults are tolerated by switching to communication-less mode of operation with online estimation of the current reference signal instead of receiving it over the communication network. The proposed algorithms are validated by simulation and experimentally on a prototype with three parallel AFRs. Adaptive communication, communication-based control, communication fault tolerant control, master-slave communication. there are major disadvantages associated with it, namely reliability, complexity, and communication delay. In master-slave communication, a fault in the master DG would lead to a failure in the entire system due to the central point of failure. Moreover, a communication fault in any slave will put the slave out of service even if it is healthy in terms of hardware. To solve the aforementioned problems, Peng et al. [10] proposed a self-triggered control method for dc microgrids. The method overcomes the problems of data dropouts and communication delays; however, it cannot deal with communication faults. INDEX TERMSAnother data driven model-based method was proposed in [11] to enable communication delay tolerant in centralized microgrid control schemes. This method also does not solve the communication faults. A hybrid control method was proposed in [12] to perform communication fault tolerant control. The load sharing was done by droop control, while the voltage regulation is done based on a CAN-bus communication network. However, this method depends on both communication and droop to perform fault tolerant control, which increases the complexity of the system. Additionally, the problems associated with the droop control appear in the response during the communication faults. A droop control method based on virtual frequency was proposed in [13] to perform some communication faults tolerant control. However, this method leads to disconnect the converter from the grid when a serious communication problem occurs.Master-slave based-control was employed extensively for the power sharing problem. The master rectifier computes the required reference current for voltage regulation and transmits it to other rectifiers as a set point of reference current. Therefore, the master (or multiple masters) rectifier operates as a voltage regulator, while other rectifiers work as current regul...