Topic 13Main contentsLast lecture reviewRealization of SPWMBlanking (Dead) time effect
Main contents • Last lecture review • Realization of SPWM • Blanking (Dead) time effect Topic 13
1.1 BasicprincipleofSPWM1) Basis: Narrow pulses with equivalentsquare but different shape have roughlyeffect when being put on the sameinertia subsystem.+f (t)4f (t)+f (t)↑f (t)G
1.1 Basic principle of SPWM 1) Basis：Narrow pulses with equivalent square but different shape have roughly effect when being put on the same inertia subsystem. 0 t 0 t 0 t f (t) f (t) f (t) 0 t f (t)
2)every small equivaleniareascompose SinusoidaPWM,SPWM.Sinusoidalwave:equalfottimeinteryalwithsinusoidalvariableamplitudeSinusoidalPwM::equalamplitudewithsinusoidalvariable width(i.e.timeinterval).otb)
l 2 ) every small equivalent areas compose Sinusoida PWM, SPWM. Sinusoidal wave: equal time interval with sinusoidal variable amplitude Sinusoidal PWM: : equal amplitude with sinusoidal variable width ( i.e. time interval)
u,UnipolarPWM3PWMsamplingbasedonareaequivalenceapproximatelyLrWudalEquivalentsinusoidalwaveb)
3) PWM samplingbased on area equivalence approximately Unipolar PWM Equivalent sinusoidal wave
UcontrolBipolarPWM3PwMsamplingbasedonareaequivalenceapproximatelytrtVcontrolYtri(a)VAOUoVs/2-Vs/2SO2(b)tri
Bipolar PWM vtri vcontrol vAo VS/2 -VS/2 tri 3) PWM samplingbased on area equivalence approximately Vˆ Vˆ 2 V tri Ao = vcontrol VS