Thispaperpresentsanewapproachtosolvemixed-variableunitcommitment(UC)problemswithnon-smoothcostfunctionsbasedonageneralizedpatternsearchfilter(GPS-filter)algorithm.AGPS-filteralgorithmdoesnotrequireanyinformationaboutthegradientoftheobjectivefunctionwhilesearchingforanoptimumsolution.Atthesametime,itisavailableforsolvingmixed-variableoptimizationproblems,whichisverysuitableforUC.AnewsuitablediscreteneighborhoodstructurewithUCcharacteristicsisproposedtoimproveGPS-filterefficiently.Alotofmultipleunits'statesarefixedbeforesearch;hence,thepollingsearchofdiscretevariableisefficientforafewuncertainunits.Numericalexperimentsareincludedtodemonstratetheproposedapproach'sabilitytohandlethehighlynonlinear,discontinuous,non-smoothcostfunctionsandmixedvariablesoftheUCproblem.
