Post on 02-Oct-2021
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
ECEN 613
Rectifier & Inverter Circuits
Professor: Dr. P. Enjeti with Michael T. DanielRm. 024, WEBEmail: enjeti@tamu.edu
michael.t.daniel@tamu.edu
Textbook: Power Electronics – Converters, Applications & Design (Third edition), by: Ned Mohan et al., John Wiley
COURSE WEBPAGE: http://eCampus.tamu.edu
Module-10b
1
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
DC-AC Inverters
� Single Phase- Half-bridge Inverter- Full-bridge Inverter- Dual output voltage configuration- Output filter design
� Three Phase Inverter- Dead-time effect
�PWM Techniques- Sinusoidal PWM- Selective harmonic elimination (SHE)- Space vector PWM
2
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
3
Voltage Source Inverter
Advantages & Disadvantages
• Voltage source inverter (VSI) is a buck type converter – ac output voltage is limited and cannot exceed the dc-link
• VSI cannot tolerate short circuits – dead time between the gating of upper and lower switches need to be provided
• Three switches are on at any given instant
• VSI can supply multiple loads
• Output voltage in PWM and exhibits high dv/dt. In the case of long motor leads, voltage reflections cause over voltages at the motor terminals. Furthermore,
high dv/dt and common mode voltages contributes to ground currents and bearing fluting
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
Voltage Source Inverter – Common mode voltage Analysis
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
Voltage Source Inverter – Common mode voltage Analysis
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
Voltage Source Inverter – Common mode voltage Analysis
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
Voltage Source Inverter – Effect of Blanking time
S1g,ideal
S2g,ideal
S1g,actual
Van,ideal
S2g,actual
Van,actual
Verror= Van,ideal – Van,actual
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
Voltage Source Inverter – Effect of Blanking time
Ref: Y. Murai, etal “Waveform distortion and correction circuit for PWM inverters with switching
lag-times”, IEEE Transactions on Industry Applications, Sep/Oct 1987
Problem 8.12 page 246
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
Mathematical Modeling of Blanking Time Effect
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
Mathematical Modeling of Blanking Time Effect
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
11
Current Source Inverter Operation
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
12
Reference: P. Enjeti, P.D. Ziogas, J.F. Lindsay, “A current source PWM inverter with instantaneous current control capability”, IEEE Transactions on Industry Applications,
May/June 1991, pp 582-588
Advantages & Disadvantages
• CSI is a boost type converter
• Load voltage and current are sinusoidal (v.low THD) & no dv/dt issues.
• Reverse voltage blocking switches are needed
• Can tolerate short circuits
• No load operation / open circuit of the load is not possible
• Applicable for single or dedicated load
• Only two switches are on at any given instant
Current Source Inverter Operation
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
13
Comparison of Current Source Inverter & Voltage Source Inverter
Current source inverter with symmetrical gated
commutated thyristors (SGCTs)
Voltage source inverter with NPC inverter and IGBT
devices
Ref: A.V. Meulen, J. Mauin “Current source inverter vs Voltage source inverter Topology”, Eaton Corp, Technical data
TD02004004E, Aug 2010
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
Comparison of Current Source Inverter & Voltage Source Inverter
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
Available Online Via http://libcat.tamu.edu
http://onlinelibrary.wiley.com/book/10.1002/0471773719;jsess
ionid=BE7EB55C85968F44A70290A287D9A702.d04t01
Further Reading
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
16
Z Source Inverter
Advantages & Disadvantages
• Z source inverter is a buck-boost type converter – ac output voltage can be boosted and exceed the dc voltage source
• Z source inverter can be short circuited – the shoot through time T0 is used to boost the output voltage
• The PWM operation of the Z source Inverter is identical to a conventional VSI. Three switches are on at any given instant
• Dc voltage source current is discontinuous (similar to a buck-boost converter)
• Presence of stray inductance between the inverter and the Z-source (dc-link) causes voltage spikes and affects performance
• Equivalent resistance of the inductors limits the boost gain and also lowers the efficiency
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
17
Z Source Inverter - Analysis
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
18
Z Source Inverter - Analysis
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
19
Z Source Inverter - Analysis
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
20
Z Source Inverter – PWM Operation
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
Z Source Inverter – PWM Operation
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.htmlECEN 613Rectifiers & Inverters
Quazi - Z Source InvertersVSI with a boost converter