Multilevel Inverters
(Copyrighted Material)
Prasad Enjeti, Ph.D.
Associate Dean for Undergraduate Programs
TI-Professor of Electrical & Computer Engineering
Power Electronics & Power Quality Laboratory
Texas A&M University, College Station, TX – 77843, USA
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Multilevel Inverters
(Copyrighted Material)
Module Outline
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Basic principle & types of multilevel inverters
Pulse width modulation techniques
Modular multilevel inverters
Applications: a) Adjustable speed ac drives, b) Solar/Wind energy
systems, c) Utility scale HVDC light systems, d) Fuel cell and
battery energy storage systems
Prasad Enjeti, Ph.D.
Associate Dean for Undergraduate Programs
TI-Professor of Electrical & Computer Engineering
Power Electronics & Power Quality Laboratory
Texas A&M University, College Station, TX – 77843, USA
http://enjeti.tamu.edu
ECEN 613 – Rectifier and Inverter Circuits
Fall 2013
Professor:
Course Notes:
Textbook:
Dr. Prasad Enjeti
Rm. 128, ZEC, Tel: 5-7466, Email: enjeti@tamu.edu
TAMU Supplementary Course Notes
Power Electronics – Converters, Applications & Design (Third edition), by: Ned Mohan
et al., John Wiley & Sons. (Available online for free: http://tx.ag/at1kus )
COURSE WEBPAGE: http://eCampus.tamu.edu Students login: use your TAMU NEO account
username & password.
ELEN 613 – Rectifier and Inverter Circuits - Fall 2013
Multilevel Inverters
3-level half-bridge
Reference: L. Helle, S.M. Nielsen, P. Enjeti, “Generalized discontinuous dc-link
balancing modulation strategy for 3-level inverters”, IEEE PCC 2002, pp 359-366
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.html
6
Multilevel Inverters - NPC
3-level half-bridge neutral point clamped (NPC)
Gating signals
Output voltage waveforms
Reference: A. Nabae, I. Takahashi, H. Akagi, “A new neutral-point clamped
PWM inverter”, IEEE Transactions on Industry Applications, Sep/Oct 1981, pp
518-523
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.html
7
Multilevel Inverters : 5-level
Van
For a m-level inverter we have:
• Number of switches = 2(m-1)
• Number of dc-link capacitors = (m-1)
• Number of clamped diodes = 2(m-2)
• Voltage across each dc-link capacitor =
ECEN 613
Rectifiers & Inverters
𝑉𝐷𝐶
(𝑚−1)
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.html
8
Multilevel Inverters - ABB
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.html
9
Secondaries
Note: A Total of 12secondaries, only 4secondaries shown
for simplicity
Medium Voltage
Utility Input
( Phase A )
Medium Voltage Adjustable Speed AC Motor Drive: ASI-Robicon – Perfect Harmony
Inverter Cells,
Similar to
Phase A
Inverter Cells,
Similar to
Phase A
N
Inv. 1c
Inv. 1b
Inv. 1a
+22.5o
a1
b1
c1
b1'
c1'
oa1
a1'
na1
Inv. 2c
Inv. 2b
Inv. 2a
+7.5o
a2
b2
c2
b2'
c2'
oa2
a2'
na2
a
ia
Inv. 3a
b
ib
Inv. 3c
Inv. 3b
o
-7.5
a3
b3
c3
b3'
c3'
oa3
c
ic
a3'
na3
Inv. 4a
Inv. 4c
Inv. 4b
-22.5o
a4
b4
c4
b4'
c4'
oa4
a4'
na4
A
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•
•
•
ECEN 613
Rectifiers & Inverters
Input current and output voltage is of high quality
Complicated multi-winding 60Hz input transformer
Single phase inverter dc-link capacitor size is large
Modular in construction & employs low voltage devices
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.html
B
C
M
10
Toshiba MV Drive
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.html
11
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.html
Power Electronics for Photovoltaic
Applications
rbalog@ece.tamu.edu
www.ece.tamu.edu/~rbalog
Dr. Robert S. Balog, PhD PE
Assistant Professor, Department of Electrical and Computer Engineering
Director, Renewable Energy & Advanced Power Electronics Research Laboratory
http://SolarAgs.tamu.edu
© 2013 Robert S. Balog
Topics covered in the module
1.
2.
3.
5.
6.
6.
Electrical characteristics and modeling of PV
Interface requirements
Maximum power point tracking, series string vs. module-level,
impedance matching
Circuit topologies
System design and applications
Standards and economics
© 2013 Robert S. Balog
Power Electronics for MPPT of PV
M. Mirjafari, R. S. Balog, and R. Turan, "Multi-Objective Optimization of the DC-DC Stage of a Module-Integrated Inverter Based on an Efficiency Usage Model," IEEE
Journal of Photovoltaics, accepted for publication 21 Jan 2014 .
P. Mazumdar, P. N. Enjeti, and R. S. Balog, "Analysis and Design of Smart PV Modules," IEEE Journal of Emerging and Selected Topics in Power Electronics
(JESTPE), available IEEE Xplorer early access, 11 Dec. 2013.
© 2013 Robert S. Balog
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