Estimation of maximum allowable time-delay bound for system stability of network controlled parallel DC/DC buck converters

The current trend in distributed energy system control is moving toward implementing quasi-decentralized control strategy where the control signals are exchanged over shared dedicated control or communication networks which reduces the complexity in the wiring and enhances the reliability. Transmitting control signals through shared networks induces time delays and data losses which may destabilize the system. So it is important to identify what the maximum allowable delay bound (MADB) can be tolerant with respect to system stability. The paper proposes a new method for estimating the allowable time delay under which the system stability can be maintained. The proposed method is originated from analyzing the network controlled parallel DC/DC Buck converters. The influences of the system parameters and controllers on the boundary of the MADB are studied. Simulation using Matlab SimPowerSystem Toolbox is performed to verify the stability bound determined by the MADB. The results are compared with the methods previously reported in the literature and the new method is proved to be simpler in estimation procedures and easier in applications to practical systems.