AnupdatedapproachtoreferenceframeanalysisofelectricmachinesanddrivesystemsSincethefirsteditionofAnalysisofElectricMachinerywaspublished,thereferenceframetheorythatwasdetailedinthebookhasbecometheuniversallyacceptedapproachfortheanalysisofbothelectricmachinesandelectricdrivesystems.N