Abstract: The present invention concerns a device for controlling a plant with an electricity generation and/or electricity storage unit and a connection terminal intended to be connected to a microgrid, comprising an automatic controller (100) configured to compute a setpoint voltage Uref(i) of each unit, members (1, 2, 3, 4i, 5) for measuring or determining a total active power Pcentrale, a voltage URmes of the terminal, of a voltage reference UcentraleRef according to a function f depending at least on the total active power Pcentrale, of a first individual reactive power Qmes(i) of each unit, a first voltage corrector (5), having a second prescribed transfer function corr, the automatic controller being configured to compute UcentraleRef=f(Pcentrale), and Uoffset=corr(UcentraleRef?URmes) and Uref(i)=Uoffset(i)?KUQ(i)?Qmes(i).