Variable-air-volume(VAV)air-conditioningsystemisamulti-variablesystemandhasmulticouplingcontrolloops.Whileallofthecontrolloopsareworkingtogether,theyinterfereandinfluenceeachother.AmultivariabledecouplingPIDcontrollerisdesignedforVAVair-conditioningsystem.Diagonalmatrixdecouplingmethodisemployedtoeliminatethecouplingbetweentheloopofsupplyairtemperatureandthatofthermal-spaceairtemperature.ThePIDcontrollerparametersareoptimizedbymeansofanimprovedgeneticalgorithminfloatingpointrepresentationstoobtainbetterperformance.Thepopulationintheimprovedgeneticalgorithmmutatesbeforecrossover,whichishelpfulfortheconvergence.Additionallythemicromutationalgorithmisproposedandappliedtoimprovetheconvergenceduringthelaterevolution.Tosearchthebestparameters,theoptimizedparametersrangesshouldbeamplified10timestheinitialidealparameters.Thesimulationandexperimentresultsshowthatthedecouplingcontrolsystemiseffectiveandfeasible.Themethodcanovercomethestrongcouplingfeatureofthesystemandhasshortergoverningtimeandlessover-shootthannon-optimizationPIDcontrol.
