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＜0.54.　The　THD　of　SPWM　outperforms　that　of　SHEPWM　if　M∈[0,　1].　Therefore,　a　correlation　does　not　exist　between　the　torque　pulsation　ratio　and　THD　ratio　for　different　PWM.　The　study　results　provide　a　new　basis　to　fairly　evaluate　the　SHEPWM　performance　and　its　harmonic　influence.