Download diodes.

‫جمهورية العراق‬
‫وزارة التعليم العالي والبحث العلمي‬
‫جامعة الكوفة‬
‫مركز تطوير التدريس والتدريب الجامعي‬
‫عثمان محمد حسين محمد علي‬
‫مركز البحت والتأهيل ألمعلوماتي‪ /‬جامعة الكوفة‬
‫‪2015‬م – ‪1437‬هـ‬
‫‪E-Mail: [email protected]‬‬
 What is an Inverter?
 Why do I need an inverter?
Applications
 Uninterruptible power supplies
 HVDC power transmission
 Electric vehicle drives
Multilevel inverter
 Types of Multilevel inverter.
1. Diode clamp multilevel inverter.
2. Flying capacitors multilevel inverter.
3. Cascade multilevel inverter.
 Advantage & disadvantage of
Multilevel inverter.
Diode Clamp multilevel Inverter
Circuit Diagram of 3 Level
Diode Clamp Inverter
 (n-1) voltage sources.
 2(n-1) switching devices.
 2(n-2) diodes.
Switching sequence
Switch state
Output
Vao
S1
S2
S3
S4
+Vdc/2
1
1
0
0
0
0
1
1
0
-Vdc/2
0
0
1
1
•Voltage level Van= Vdc/2, turn on the switches S1andS2.
•Voltage level Van= 0, turn on the switches S2 and S3.
•Voltage level Van= - Vdc/2 turn on the switches S3,S4.
The major advantages of the diode clamp
inverter
 When the number of levels is high enough, the
harmonic content is low enough to avoid the
need for filters.
 Inverter efficiency is high because all devices
are switched at the fundamental frequency.
 The control method is simple.
Comparison of Components of Multilevel
Inverters
Converter type
Cascade H-
Diode Clamp
Flying Capacitors
(m-1)*2
(m-1)*2
(m-1)*2
Clamping diodes
2(m-2)
0
0
Dc bus capacitors
(m-1)
(m-1)
(m-1)/2
0
(m-1)* (m-2)/2
0
Main switching
device
Balancing
capacitors
Bridge
The key features of a multilevel inverter
 The output voltage and power increase with number
of levels.
 The harmonic content decreases as the number of
levels increases.
 Absence of any PWM techniques, the switching losses
can be avoided.
 Multilevel inverters can easily be applied for highpower applications.
References
 [1] Dr.P.S.Bimbra ’power electronics’ third edition,
1999.
 [2] Mohan undelan driobbins ‘power electronics
converters, applications, and design’ third edition,
2012.
 [3] Muhammad H. Rashid 'power electronics circuits,
devices, and applications', third edition. eleventh
impression,2012.