EFE1 DCAC invertere, sinsformet AC Mohahan Kap' 8'123

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EFE1 DCAC invertere, sinsformet AC Mohahan Kap' 8'123

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converters for ac motor drives and uninterruptible power supplies. X. X. X. Side 3 af 15 ... of a motor drive where the power flow can be bi-directional. Side 5 ... – PowerPoint PPT presentation

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Title: EFE1 DCAC invertere, sinsformet AC Mohahan Kap' 8'123

1
EFE1DC-AC invertere, sinsformet ACMohahan Kap.
8.1-2-3

J.Nybo
07.03.03
Rev.02.05.05

2
Chapter 8 Switch-Mode DC-AC Inverters
X X X

converters for ac motor drives and
uninterruptible power supplies

3
Switch-Mode DC-AC Inverter

Block diagram of a motor drive where the power
flow is unidirectional

4
Switch-Mode DC-AC Inverter

Block diagram of a motor drive where the power
flow can be bi-directional

5
Switch-Mode DC-AC Inverter

Four quadrants of operation

6
One Leg of a Switch-Mode DC-AC Inverter

The mid-point shown is fictitious

7
Synthesis of a Sinusoidal Output by PWM
8
Details of a Switching Time Period

Control voltage can be assumed constant during a
switching time-period

9
Harmonics in the DC-AC Inverter Output Voltage

Harmonics appear around the carrier frequency
and its multiples

10
Eksempel
11
Valg af switch frekvens fs
12
Harmonics due to Over-modulation
Bedre udstyring, men flere harmoniske. (sinus
klippes i toppen) Det anbefales at bruge synkron
PWM.

These are harmonics of the fundamental frequency

13
Output voltage Fundamental as a Function of the
Modulation Index

Shows the linear and the over-modulation
regions square-wave operation in the limit

14
Square-Wave Mode of Operation
Fordele Bedre udnyttelse af DC
spændingen. Square-Wave modulation Er et
specialtilfælde af PWM, Hvor amplitude
modulations Indekset er meget større en 1