Design, Modeling and control of modular multilevel converters (MMC) based hvd...Ghazal Falahi
Modular multilevel converter (MMC) is a relatively new and promising topology, which has gained a lot of interest in industry in the recent years due to its modular design and easy adaption for applications that require different power and voltage level, such as power transmission through HVDC. This presentation investigates the operation of MMC based HVDC systems and proposes new solutions to improve the performance of the system by using new devices and improving the control strategies.
Design, Modeling and control of modular multilevel converters (MMC) based hvd...Ghazal Falahi
Modular multilevel converter (MMC) is a relatively new and promising topology, which has gained a lot of interest in industry in the recent years due to its modular design and easy adaption for applications that require different power and voltage level, such as power transmission through HVDC. This presentation investigates the operation of MMC based HVDC systems and proposes new solutions to improve the performance of the system by using new devices and improving the control strategies.
This ppt gives the basic idea about multilevel inverter.this ppt includes
1.Introduction
2.Advantages of multilevel inverters
3.Types of multilevel inverters
4.Working of multilevel inverters
5.Applications.
We had made a working model on static VAR compensator which is made by power electronic switch and mechanically switched. We had chosen mechanically switched capacitor method to improved receiving end voltage as well as power factor.
this is useful for peoples interested in power quality problems and their mitigation. it provides causes, effects of voltage sag and their mitigation techniques.
In microgrid, if fault occurs or any other contingency happens, then the problems would be created which are related to power flow, also there are various protection schemes are used for minimize or eliminate these problems.
Voltage control is used for reactive power balance and P-f control is used for active power control.
Various protection schemes such as, over current protection, differential protection scheme, zoning of network in adaptive protection scheme are used in microgrid system .
Distributed Generation generally refers to power generation at the point of end user or
customer. Distributed Generation is gaining worldwide acceptance due to it’s a number of benefits.
Distributed Generation eliminates the cost and complexity and reduces the chances of inefficiency
which occur in the transmission and distributed network [1]. Basically electricity produced is
generated at large generating stations which is then send at high voltages through the transmission
lines to the load centers and then through local distribution network distributed to the customers at
distribution level voltage. In present scenario there is an increase in demand which is creating gap
between demand and supply to fulfill this gap distributed generation can plays the significant role.
The main reason for the need of distributed generation is it is clean and continuous. Distributed
generation means generating power on site not centrally. Distributed generation is the best way for
rural electrification. This paper will discuss the importance and benefits of Distributed Generation in
near future
This paper addresses a novel approach for designing and modeling of the isolated
flyback converter. Modeling is done without parasitic as well as with parasitic components.
A detailed analysis, simulation and different control strategy are conferred for flyback
converter in continuous conduction mode (CCM). To verify the design and modeling at
primary stage, study of the converter is practiced in CCM operation for input AC voltage
230V at 50Hz and output DC voltage of 5V and 50W output power rating using PSIM 6.0
software. Simulation result shows a little ripple in output of the converter in open loop. Finally
in order to evaluate the system as well as response of the controller, flyback converter is
simulated using MATLAB. This work, highlighting the modeling when the system have
transformer and facilitate designers to go for it when they need one or more than one output
for a given application upto 150W
Soft Switched Multi-Output Flyback Converter with Voltage DoublerIJPEDS-IAES
A novel multi-output voltage doubler circuit with resonant switching
technique is proposed in this paper. The resonant topology in the primary
side of the flyback transformer switches the device either at zero voltage or
current thus optimizing the switching devices by mitigating the losses. The
voltage doubler circuit introduced in the load side increases the voltage by
twice the value thereby increasing the load power and density. The proposed
Multi-output Isolated Converter removes the need for mutiple SMPS units
for a particular application. This reduces the size and weight of the
converters considerably leading to a greater payload. This paper aims at
optimizing the proposed converter with some design changes. The results
obtained from the hardware prototype are given in a comprehensive manner
for a 3.5W converter operating at output voltages of 5V and 3.3V at 50 kHz
switching frequency. The converter output is regulated with the PI controller
designed with SG3523 IC. The effects of load and line regulation for ±20%
variations are analyzed in detail.
This ppt gives the basic idea about multilevel inverter.this ppt includes
1.Introduction
2.Advantages of multilevel inverters
3.Types of multilevel inverters
4.Working of multilevel inverters
5.Applications.
We had made a working model on static VAR compensator which is made by power electronic switch and mechanically switched. We had chosen mechanically switched capacitor method to improved receiving end voltage as well as power factor.
this is useful for peoples interested in power quality problems and their mitigation. it provides causes, effects of voltage sag and their mitigation techniques.
In microgrid, if fault occurs or any other contingency happens, then the problems would be created which are related to power flow, also there are various protection schemes are used for minimize or eliminate these problems.
Voltage control is used for reactive power balance and P-f control is used for active power control.
Various protection schemes such as, over current protection, differential protection scheme, zoning of network in adaptive protection scheme are used in microgrid system .
Distributed Generation generally refers to power generation at the point of end user or
customer. Distributed Generation is gaining worldwide acceptance due to it’s a number of benefits.
Distributed Generation eliminates the cost and complexity and reduces the chances of inefficiency
which occur in the transmission and distributed network [1]. Basically electricity produced is
generated at large generating stations which is then send at high voltages through the transmission
lines to the load centers and then through local distribution network distributed to the customers at
distribution level voltage. In present scenario there is an increase in demand which is creating gap
between demand and supply to fulfill this gap distributed generation can plays the significant role.
The main reason for the need of distributed generation is it is clean and continuous. Distributed
generation means generating power on site not centrally. Distributed generation is the best way for
rural electrification. This paper will discuss the importance and benefits of Distributed Generation in
near future
This paper addresses a novel approach for designing and modeling of the isolated
flyback converter. Modeling is done without parasitic as well as with parasitic components.
A detailed analysis, simulation and different control strategy are conferred for flyback
converter in continuous conduction mode (CCM). To verify the design and modeling at
primary stage, study of the converter is practiced in CCM operation for input AC voltage
230V at 50Hz and output DC voltage of 5V and 50W output power rating using PSIM 6.0
software. Simulation result shows a little ripple in output of the converter in open loop. Finally
in order to evaluate the system as well as response of the controller, flyback converter is
simulated using MATLAB. This work, highlighting the modeling when the system have
transformer and facilitate designers to go for it when they need one or more than one output
for a given application upto 150W
Soft Switched Multi-Output Flyback Converter with Voltage DoublerIJPEDS-IAES
A novel multi-output voltage doubler circuit with resonant switching
technique is proposed in this paper. The resonant topology in the primary
side of the flyback transformer switches the device either at zero voltage or
current thus optimizing the switching devices by mitigating the losses. The
voltage doubler circuit introduced in the load side increases the voltage by
twice the value thereby increasing the load power and density. The proposed
Multi-output Isolated Converter removes the need for mutiple SMPS units
for a particular application. This reduces the size and weight of the
converters considerably leading to a greater payload. This paper aims at
optimizing the proposed converter with some design changes. The results
obtained from the hardware prototype are given in a comprehensive manner
for a 3.5W converter operating at output voltages of 5V and 3.3V at 50 kHz
switching frequency. The converter output is regulated with the PI controller
designed with SG3523 IC. The effects of load and line regulation for ±20%
variations are analyzed in detail.
The power electronics device which converts DC power to AC power at required output voltage and frequency level is known as inverter. Multilevel inverter is to synthesize a near sinusoidal voltage from several levels of dc voltages. In order to maintain the different voltage levels at appropriate intervals, the conduction time intervals of MOSFETS have been maintained by controlling the pulse width of gating pulses. In this paper single phase to three phase power conversion using PWM technique. The simulation is carried out in MATLAB/Simulink environment which demonstrate the feasibility of proposed scheme.
Design consideration of an mmc hvdc system based on 4500 v:4000a emitter turn...Ghazal Falahi
Excessive power loss is a major concern in high voltage and high power applications and is considered one of the main drawbacks of VSC-HVDC system when compared with traditional HVDC system based on thyristor technology. This is primarily caused by high switching loss associated with switching devices used in the VSC-HVDC. This issue can be largely addressed by using the emerging MMC-HVDC topology, which requires much lower switching frequency than traditional VSC-HVDC. Emitter turn-off thyristor (ETO) is one of the best high power switching devices packed with many advanced features. ETO thyristor based MMC-HVDC system is therefore an extremely attractive choice for ultra-high voltage and high power HVDCs. This paper discusses the operation principle of ETO based MMC-HVDC as well as its design and loss comparison with other solutions.
In this paper Low power low voltage CMOS analog multiplier circuit is proposed. It is based on flipped voltage
follower. It consists of four voltage adders and a multiplier core. The circuit is analyzed and designed in 0.18um
CMOS process model and simulation results have shown that, under single 0.9V supply voltage, and it
consumes only 31.8μW quiescent power and 110MHZ bandwidth.
Digital Current Mode Controller for Buck ConverterIJMREMJournal
Power electronics applications are widely used in different fields of engineering like computer,
Telecommunication, electrical power and Mechanical), one of the most useful power electronics converters is
DC-DC buck converter. Owing to its numerous applications, its performance needs to be improved through a
suitable controller. In this Paper, A digital current mode controller is proposed and implemented for Buck
converter. Proposed current mode control technique is simulated in MATLAB/SIMULINK and results are
validated through hardware implementation. Both simulation and experimental analysis show effectiveness of
the proposed controller.
IC Design of Power Management Circuits (I)Claudia Sin
by Wing-Hung Ki
Integrated Power Electronics Laboratory
ECE Dept., HKUST
Clear Water Bay, Hong Kong
www.ee.ust.hk/~eeki
International Symposium on Integrated Circuits
Singapore, Dec. 14, 2009
This paper presents combinations of level shifted pulse-width modulation algorithm with conventional discontinuous pulse-width modulation methods for cascaded multilevel inverters. In the proposed DPWM a zero sequence signal is injected in sinusoidal reference signal to generate various modulators with easier implementation. The analysis four various control strategies namely Common Carrier (CC), Inverted Carrier (IC), Phase Shifted (PS) and Inverted Phase Shift (IPS) for cascaded multilevel inverter fed induction motor drive has been illustrated. To validate the proposed work experimental tests has been carried out using dSPACE controller. Experimental study proves that using proposed algorithms reduction in common-mode voltage with fewer harmonics along with reduced switching loss for a cascaded multilevel inverter fed motor drive has been achieved.
PID Controller Response to Set-Point Change in DC-DC Converter ControlIAES-IJPEDS
Power converter operations and efficiency is affected by variation in supply
voltage, loads current, circuit elements, ageing and temperature. To meet the
objective of tight voltage regulation, power converters circuit module and the
control unit must be robust to reject disturbances arising from supply, load
variation and changes in circuit elements. PID controller has been the most
widely used in power converter control. This paper presents studies of
robustness of PID controller tuning methods to step changes in the set point
and disturbance rejection in power converter control. A DC-DC boost
converter was modelled using averaged state-space mothod and PID
controllers were designed with five different tuning methods. The study
reveals the transient response and disturbance rejection capability of each
tuning methods for their suitability in power supply design applications.
Common Mode Voltage Control in Three Level Diode Clamped InverterIJERA Editor
This paper presents simple sinusoidal PWM technique to reduced common mode voltage (CMV) at output terminal of the inverter. Multilevel inverter (MLI) is more suitable in high & medium power application, CMV is produced at the time of operation in output terminal of inverter. In this paper, an approach to reduced CMV at output terminal of MLI by using SPWM technique in three level diode clamped inverter (DCMLI) is proposed. A good transaction between the quality of the output voltage & the magnitude of CMV is achieved in this paper. The paper presents phase opposition & phase opposition disposition SPWM technique to reduced CMV in DCMLI. Simulation & experimental result presented to confirm the effectiveness of the proposed technique to control CMV.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
CW RADAR, FMCW RADAR, FMCW ALTIMETER, AND THEIR PARAMETERSveerababupersonal22
It consists of cw radar and fmcw radar ,range measurement,if amplifier and fmcw altimeterThe CW radar operates using continuous wave transmission, while the FMCW radar employs frequency-modulated continuous wave technology. Range measurement is a crucial aspect of radar systems, providing information about the distance to a target. The IF amplifier plays a key role in signal processing, amplifying intermediate frequency signals for further analysis. The FMCW altimeter utilizes frequency-modulated continuous wave technology to accurately measure altitude above a reference point.
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
plant could also recover latent heat due to condensation as well
as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
2. Modular Multilevel Converter (MMC) structure
2
SM
2
SM
n
SM
(n+1)
SM
(n+2)
SM
1
SM
(2n)
DC
link
va
vb
vc
u0
ipa
Udc/2
Udc/2
ia
ib
ic
Larm
La
Lb
Lc
ipb ipc
ua
ub
uc
Rarm
D1
D2
S1
S2
ipa Vc
incinbina
Larm Larm
Rarm
Rarm
Larm
Rarm
Larm Larm
Rarm
Rarm
q Modular multilevel converter
1. Series connection of sub-modules
Make the arm of the converter to build
the output voltage stepwise
2. Sub-modules are Half-bridge (HB) or
Full-bridge (FB) converters
3. Each sub-module has a capacitor
with average voltage of Udc
N
arm
leg
4. With n sub-modules in arm of the
converter output voltage has n+1 levels
4. 4
va
vb
vc
u0
ia-‐up
ia-‐low
Udc/2
Udc/2
ia
ib
ic
Larm
La
Lb
Lc
ib-‐up ic-‐up
ib-‐low ic-‐low
ua
ub
uc
Rar
m
Larm Larm
Larm Larm Larm
Rar
m
Rarm
Rarm Rarm Rarm
Inner
voltage
Inner
voltage
Inner
voltage
Inner
voltage
Inner
voltage
Inner
voltage
N ≥
Udc
Usm
Modular Multilevel Converter operation
q MMC equivalent circuit
q Number of sub-modules in
MMC arm
Each arm of the converter is equivalent
To a controlled voltage source with
magnitude of and a series
inductor
Where nactive is number of inserted
sub-modules
nactive ×Udc
N
5. MMC advantages and disadvantages
1. Low THD
2. Low on devices and good voltage sharing for semiconductors
3. Modular structure with identical modules which has redundancy and allows to substitute failed
modules
4. Scalable and no DC link voltage limitation
5. Simple mechanical construction
6. No need for bulk filters on ac side
7. Lower losses
5
dv
dt
q Advantages
q Disadvantages
1. Extra controller required for balancing of capacitor voltages
2. Need for monitoring all capacitor voltages
3. Circulating current consisting double fundamental frequency component and increases device
losses if not suppressed
6. MMC mathematical equations
6
icirc =
ip +in
2
varm = vSM
i=0
n
∑ + Larm
diarm
dt
+ Rarmiarm
uk − u0 = varm
uk − (vk + u0 ) = varm
Vk : Phase voltage
K= a, b, c
uk (t) =
Udc
2
mk (t)
mk (t) = mcos(ω0t +ϕ)
q MMC mathematical model
q MMC grid connection dynamic
Arm voltage
Output voltage
Circulating current
Modulation
Output voltage
7. MMC operation and analysis
7
)cos(
22
)(,_ t
V
m
V
tV dcdc
refkarm ω−=
)cos(
23
)( ϕω −+= t
II
ti adc
arm
Upper arm reference voltage
Arm current
Varm,ref
iarm
D2 conducts
S2 conductsD1 conductsS1 conducts
0
q Device operation in MMC sub-module
m = 1
φ = 0
8. iarm>0 S1 or D2
S1
D2
iarm<0 S2 or D1
D1
S2
Device operation principal in MMC sub-modules
8
The arm current flowing out of the sub-module is considered as positive (a) and the
current flowing into sub-module is considered as negative
D1
D2
S1
S2
ipa
Vc
D1
D2
S1
S2
ipa
Vc
D1
D2
S1
S2
ipa
Vc
D1
D2
S1
S2
ipa
Vc
(a) iarm>0
(b) iarm<0
0
,
>
dt
dV refarm
0
,
<
dt
dV refarm
0
,
>
dt
dV refarm
0
,
<
dt
dV refarm
q Logic of operation
1. Direction of arm current determines which devices can operate
2. The rate reference arm voltage change determines if a sub-
module is inserted or bypassed
State S1 S2 Vsm
1 ON OFF Vc
2 OFF ON 0
9. Semiconductor rating
9
I!"#!$(t) =
I!"
3
±
!!" 2
2
sin!(!")
!!_!"# =
!!"
!
4
+
!!"
!
9
Valve current:
Valve rms current:
q Device voltage
Device voltage rating is the average capacitor voltage rating of sub-modules
With a margin depending on maximum allowed ripple
Udc
N
q Device current
Device current in MMC is found from the following equations
10. Modular Multilevel Converter Conventional Control [1]
10
1. An individual capacitor voltage controller
2. The averaging controller
3. The system controller
4. Modulation reference generation
PI PI
1/2
Vc*
Vcu
Ik-‐low
Ik-‐up
Icir*
Icir
VAu*
Total DC voltage controller
PI
Vc*
Vcju
(j=1-‐2n)
±
-1 :-Ik-up , Ik-low ≥ 0
+1 :-Ik-up , Ik-low ≤ 0
VBju*
Individual DC voltage controller
Vmk(k=a,b,c)
PI
i*dref
Vod
iod
PI
i*qref
ω0Leq
ω0Leq
ioq
Voq
3dq/abc
System controller !
[1] Hagiwara, Makoto, and Hirofumi Akagi. "Control and experiment of pulsewidth-modulated modular multilevel
converters." Power electronics, IEEE Transactions on 24.7 (2009): 1737-1746.
VAu*
VBju* Vi/n E/(2n)
Vju*
(j=1-‐n)
dAneg
VAu*
VBju* Vi/n E/(2n)
Vju*
(j=n+1-‐2n)
dAneg
Modulation reference generation
11. MMC modulation methods
11
[1] Wang, Jun, Rolando Burgos, and Dushan Boroyevich. "A survey on the modular multilevel converters—Modeling,
modulation and controls." Energy Conversion Congress and Exposition (ECCE), 2013 IEEE. IEEE, 2013.
Multilevel
Modulation
Fundamental switching
frequency
High switching
frequency
Space vector
PWM
Sinusoidal
PWM
Level shifted
PWM
Phase shifted
PWM
Space vector
control SHENLM
High switching frequency modulation
techniques
ü Suitable for small & large number of sub-modules
ü Lower harmonics
× High losses
Fundamental switching frequency modulation
techniques
ü Suitable for large number of sub-modules
ü Lower losses
12. Passive components design ( Arm inductor
and Sub-module capacitor)
12
L ≥
Vdc
2αmax
!! =
1
(8!!
!
!!!!)
(
!!
3!!!
+ !!")
!!" =
!!
3.!.!.!!.!.!!
!
1 − (
!.!"#$
2
)!
!
!
Ps: three phase apparent power
K: voltage modulation index
Cosφ: power factor
N: number of sub-modules,
ω0 is the fundamental frequency,
VC: mean value of sub-module voltages
ε: sub-module voltage ripple
[1] Tu, Qingrui, et al. "Parameter design principle of the arm inductor in modular multilevel converter based HVDC." Power System Technology (POWERCON),
2010 International Conference on. IEEE, 2010.
[2] Zygmanowski, Marcin, Boguslaw Grzesik, and Radoslaw Nalepa. "Capacitance and inductance selection of the modular multilevel
converter." Power Electronics and Applications (EPE), 2013 15th European Conference on. IEEE, 2013.
1. Limit the circulation current
2. Limit the fault current rise rate
q Criteria to select arm inductor [1]:
q Sub-module capacitor selection [2]:
1. Provide the output power for at least one cycle
If DC link is defective
2. Limit sub-module voltage ripple
13. Three phase line PWM voltages and phase currents in
MMC with sub-modules in each arm
13
0.5 0.51 0.52 0.53 0.54 0.55 0.56 0.57 0.58 0.59 0.6
-1
-0.5
0
0.5
1
time (secs)
Phasecurrents(pu)
ia
ib
ic
0.5 0.51 0.52 0.53 0.54 0.55 0.56 0.57 0.58 0.59 0.6
-2
-1
0
1
2
time (secs)
Line-LinePWMvoltages(pu)
VaLL
VbLL
VcLL
Simulation results of a grid connected MMC with 3 sub-modules in each arm in Matlab
14. Arm voltages and sub-module voltages of
the simulated MMC
14
0.5 0.51 0.52 0.53 0.54 0.55 0.56 0.57 0.58 0.59 0.6
0.97
0.98
0.99
1
1.01
1.02
1.03
time (secs)
Sub-modulescapacitorvoltages(pu)
Vsm1
Vsm2
Vsm3
Vsm4
Vsm5
Vsm6
0.5 0.51 0.52 0.53 0.54 0.55 0.56 0.57 0.58 0.59 0.6
0
0.5
1
1.5
2
2.5
3
time (secs)
Phase1upperandlowerarmvoltages(pu)
15. References
[1] Falahi, Ghazal. "Design, Modeling and Control of Modular Multilevel Converter based HVDC
Systems." PhD Dissertation NCSU (2014).
[2] Falahi, Ghazal, and Alex Q. Huang. "Design consideration of an MMC-HVDC system based on
4500V/4000A emitter turn-off (ETO) thyristor." Energy Conversion Congress and Exposition (ECCE),
2015 IEEE. IEEE, 2015.
[3] Falahi, Ghazal, and Alex Huang. "Control of modular multilevel converter based HVDC systems
during asymmetrical grid faults." Industrial Electronics Society, IECON 2014-40th Annual Conference
of the IEEE. IEEE, 2014.
[4] Falahi, Ghazal, Wensong Yu, and Alex Q. Huang. "THD minimization of modular multilevel
converter with unequal DC values." Energy Conversion Congress and Exposition (ECCE), 2014 IEEE.
IEEE, 2014.
[5] Falahi, Ghazal, and Alex Huang. "Low voltage ride through control of modular multilevel converter
based HVDC systems." Industrial Electronics Society, IECON 2014-40th Annual Conference of the
IEEE. IEEE, 2014.
15