In　order　to　study　SHEPWM＇s　harmonic　influence,　the　numerical　analysis　is　applied　to　calculate　SHEPWM　line-voltage　waveform　characteristics,　harmonics　distribution,　THD,　and　torque　pulsation　over　the　complete　fundamental　voltage　range.　Further,　numeric　comparisons　are　performed　on　above-mentioned　parameters　but　with　an　asymmetric　regular　sampled　SPWM.　The　results　show　that,　under　the　same　switching　frequency,　SHEPWM　is　superior　to　SPWM　in　terms　of　torque　and　speed　pulsation　only　if　the　modulation　index　M＞0.54;　while　SHEPWM　has　no　superiority　if　M