Multi-objective analysis for designing and controlling micro-grids under multi-control with PID, MHCC and FOPID controllers

The present paper deals with the study and the implementing of an independent micro-grid supplied from DC batteries and including a conventional boost converter and a multilevel inverter. To ensure high stability of the network and continuity of service of the whole, this assembly is simultaneously controlled by three cascaded controls: a conventional PID corrector watching the output DC bus bar of Boost Converter, a Modulated Hysteresis Current Control (MHCC) acting on a Three-level Three-phase Load Point Clamped (LPC) Inverter, a Fractional Order PID (FOPID) controlling the three-phase voltages of an autonomous electrical network. In order to make the cost of network very competitive and to respect international EMC and EMI standards, the sizing of the passive elements of the assembly and the adjusting of the correctors parameters are achieved by the multi-objective optimization method. This optimization is submitted to the following constraints: low switching frequencies for the boost converter and the multilevel inverter, weights and sizes relatively small of the inductor coils. Analysis by simulation and experimental results are presented in the paper for verifying the merits and the practicality of the three controls here developed, and so highlighting the expected performances of the whole micro-grid.