Jeollabuk-do 54538, Korea * Correspondence: swlee94@wku.ac.kr; Tel.: +82-63-850-6968 Received: 9 April 2020; Accepted: 3 May 2020; Published: 6 May 2020 Featured Application: Optimal design of permanent magnet synchronous motors (PMSMs) used in electric compressors in electric vehicles. ...