《电力电子技术》课程教学课件（PPT讲稿）Topic 12 AC square waveforms inverter、Theorem of SPWM（2）

3) THD (Total Harmonic Distortion)0Definition:u2dt-u?UaisTHDUiU1Based onFourieranalysis,orfrequencydomain analysisIn square wave on this page, we can obtainUdis=78 1 = 0.4834THD :Zn=3,5,7,U1

U1, f1 v1 t Definition: 3) THD (Total Harmonic Distortion) In square wave on this page, we can obtain Based on Fourier analysis, or frequency domain analysis

4) Crest Factor0Definition:UspeakCF-UsIn squarewave onthis page,we can obtainCFCF = V2In sinusoidal waveform,we can obtain

U1, f1 v1 t Definition: 4) Crest Factor In square wave on this page, we can obtain In sinusoidal waveform, we can obtain

5) Power FactorA.Definition of DisplacementPower0Factor:DPF= cos(Qu, - Q1)=COSP1B.Definition of Power FactorPPF-PSPF=S1UIDPFcos甲1cosDPFUUsDPFV1+THD2DPF+THSupposingvoltageis sinusoidal.Supposing currentis sinusoidal

U1, f1 v1 t A. Definition of DisplacementPower Factor: 5) Power Factor B. Definition of Power Factor: Supposing voltage is sinusoidal. Supposing current is sinusoidal

5)PowerFactorIn square wave on this page,we can obtainPF=DPF=0.81DPFSupposingvoltage is sinusoidal.In sinusoidal waveform, we can obtainPFDPF=DPF

U1, f1 v1 t 5) Power Factor In square wave on this page, we can obtain Supposing voltage is sinusoidal. In sinusoidal waveform, we can obtain

1.3 Regulation of voltage amplitude in 1 leg inverter十不5U1, f1AN,V1PotU1>U3U3, f1aU3, f1ot01Val.Pattern1Pattern2

1.3 Regulation of voltage amplitude in 1 leg inverter ZL U1, f1 U3, f1 U3, f1 Pattern 1 Pattern 2 v1 t v1 t v1 t A o U1>U3