1. Department of Electrical Engineering,
University of Engineering and Technology, Lahore
DC Fault Tolerant Modular Multilevel
HVDC Converter using Switched Capacitor
Submodule
Group No: 29
Project Advisor: Mr. Mustafeez-ul-Hassan
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
2. Team Introduction
Farhan Aslam (Team Leader)
2014-EE-118
Specialization: Power
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
Muhammad Hamza Tariq
2014-EE-119
Specialization: Power
Hamza Ayoob
2014-EE-113
Specialization: Power
Muhammad Adnan Khalid
2014-EE-117
Specialization: Power
3. Problem Statement
• Renewable Electric Sources are getting popular these
days, because of being environmental friendly.
Moreover, load centers are located far away from the
generating power stations. In order to transmit bulk
power over such a large distance, HVAC power
transmission becomes less economical than HVDC
power transmission technique.
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
5. Problem Statement
• As most of our load operates on AC, so it becomes
necessary to convert the DC power at the receiving end
into AC with greater efficiency and minimum possible
Total Harmonic Distortion (THD).
• Moreover, HVDC circuit breakers are also quite
expensive and difficult to manufacture. So, it’s
alternative protection system must be preferred, if any.
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
6. Proposed Solution
• Modular Multilevel HVDC Converter serve the
purpose of DC to AC conversion with lesser THD and
voltage rating scalability.
• The SCSM used, is capable of tolerating DC side fault
without the application of DC circuit breakers.
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
11. Advantages
• Increased number of submodules offers lesser THD.
• No need of DC circuit breakers.
• Lesser number of voltage sensors required.
• Voltage rating scalability.
• Number of levels, of output voltage, increases by
cascading submodules (SMs) in MMC.
• Reliable and easier maintenance.
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
12. Applications
• HVDC Transmission System.
• DC to AC Conversion for Renewable sources.
• Medium-voltage motor drives.
• The MMC topology provides improved dynamic
stability of transmission systems, increased power
quality, flexibility to adapt to different power ratings
STATCOM systems.
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
13. Audience
• The project is targeted towards the HVDC transmission
industry, for long distance transmission or power trade.
• The Switched Capacitor Submodule (SCSM), is
capable of tolerating any kind of DC side fault without
any need of DC Circuit breakers, that results in reduced
initial cost of converting stations.
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
14. Audience
• SCSM is capable of providing 3 level voltages, using
two capacitors. Successful voltage balancing can be
achieved by using half the number of voltage sensors,
i.e. one voltage sensor per SM, that reduces the
implementation cost to a great extent.
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
15. What we have done so far?:
• Simulation (using MATLAB) and complete
understanding of the basic operation of Modular
Multilevel Converters (MMC)
• Explored different switching techniques suitable for
MMC.
• Implementation of SCSM on hardware.
• Successfully implemented single phase, three level
SCSM based MMC on hardware.
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
17. Hardware Developed
• Gate driver circuits’ operation using 4N35 optocoupler
and isolated DC supplies.
• Implementation of switched capacitor submodule
(SCSM).
• Prototyped a working single phase three level MMC
using switched capacitor submodule (SCSM)
• Generation of SPWM signals for 3-phase, 5 level
MMC using NI myRIO FPGA.
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
20. Hardware Developed
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
SCSMs cascaded to form
a 3-level, Single phase,
Modular Multilevel
Converter (MMC)
21. Future Deliverables
• Implemented a working single phase three level MMC.
• Extend the 2 SMs per leg, to 4 SMs per leg, for 5 level
operation of MMC.
• Make the converter DC fault tolerant.
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
23. References
• Ahmed A. Elserougi, Ahmed M. Massoud and Shehab
Ahmed, “A Switched-Capacitor Submodule for
Modular Multilevel HVDC Converters with DC-Fault
Blocking Capability and a Reduced Number of
Sensors”, IEEE Trans. Power Del., Vol. 31, No. 1, Feb.
2016
• Bariş Çiftçi “Selection of suitable PWM switching and
control methods for MMC Drives”, Middle East
Technical University Department of Electrical and
Electronics Engineering, Dec. 2014
Undergraduate Final Year Project Presentation
Dated: 4th April, 2018
