The document outlines the design and implementation of a prototype nine-level cascaded multilevel inverter using FPGA to generate desired AC output voltage via sinusoidal pulse width modulation (SPWM). It details the hardware setup, including the use of Xilinx software for signal generation and the integration of multiple full-bridge inverters for achieving varied voltage levels. Performance analysis indicates that PWM switching schemes demonstrate lower total harmonic distortion in the inverter's output.

1. 1

2.  A Prototype model of Field Programmable Gate
Array (FPGA) Based Nine Level Cascaded
Multilevel Inverter is to be designed and
Implemented to produce AC output voltage of
desired magnitude and frequency.
 Xilinx software is used in FPGA for producing
SPWM gating signals to the MOSFETs for
producing the required AC output voltage.
2

3. B.Shanthi, Natarajan.S.P, “FPGA based Fuzzy
Logic Control for Single Phase Multilevel
Inverter”.
International Journal of Computer Applications
(0975-8887)
Volume9-No:3,November 2010.
3

4.  Azli, N.A. and Yatim, A.H.M.2001 Modular Structured Multilevel
Inverter (MSMI) for high power Multilevel Inverter (MSMI). In:
Proceedings of the 4th IEEE International Conference on Power
Electronics and Drive Systems PEDS’01, Vol.2, 598-604.
 Lai, J.S.and Peng, F.Z.: Multilevel Converters-A New Breed of Power
Converters. In: IEEE Trans. Ind. Application., May/June 1996, Vol. 32,
509-517.
 Carrara, G. and Gardella, S., Marchesoni M.,Salutari R.,Sciutto G.. A
New Multilevel PWM Method: A Theoretical Analysis. In: IEEE Trans.
Power Electron, July 1992, Vol. 7, 497–505.
4

5. 5
A proto type Single Phase Nine Level Cascaded Multilevel
Inverter with Sinusoidal Pulse Width Modulation
(SPWM) technique is implemented.
A Cascaded Multilevel Inverter consists of four full wave
bridge inverters connected in series on the AC output side.
Each bridge can create three different voltage levels in ac
output allowing an overall Nine Level AC output voltage.
FPGA Programmable Logic Device developed by Xilinx is
used for SPWM generator to supply the approximate signals
to the Power Inverter Switches.

6. 6
PWM
GENERATIOR
MODEL IN
XILINIX
DOWNLOADED
TO
I/O PORT OF
FPGA
CASCADED
NINE LEVEL
INVERTER
LC FILTER
&
LOAD
OPTO
COUPLER
&
MOSFET
DRIVER
+ DC input -
Nine
level
AC
output
BLOCK DIAGRAM

7. 7

8.  Proto type model of a Single Phase Nine Level
Cascaded MLI has been fabricated for an output
voltage of 48v(Peak-Peak). The MOSFET
switches are used in the power circuit.
 Gating signals are generated from FPGA
Controller. Driver circuit is used to amplify the
signals.
 Hardware model consists of the following circuits
 Power circuit.
 FPGA controller circuit.
 Driver and opto coupler circuit.
 Power supply unit.
8

9. 9

10. 10

11.  FPGA controller is used to generate sinusoidal
pulse width modulation gating signals to the
switches.
 Xilinix software is used for SPWM generator to
supply the approximate signals to the power
inverter switches.
11

12. 12

13.  An FPGA consists of an array of logic blocks,
surrounded by programmable I/O blocks, and
connected with programmable interconnect. A
typical FPGA contains from 64 to tens of thousands
of logic blocks and an even greater number of flip-
flops.
 Each logic cell can independently take on any one
of a limited set of personalities. The individual cells
are interconnected by a matrix of wires and
programmable switches.
13

14.  Key components and features
 Clock source.
 Switches and leds.
 Character led screen.
 Rc232 serial port.
 Ps/2/mouse/key board port.
 Analog to digital converter & digital to analog
converter.
 Pwm generator.
14

15.  * 100,000-gate Xilinx Spartan-3E XC3S100E FPGAin a 144-Thin
Quad
 Flat Pack package (XC3S100E-TQ144)
 # 2,160 logic cell equivalents
 # Four 18K-bit block RAMs (72K bits)
 # Four 18x18 pipelined hardware multipliers
 # Two Digital Clock Managers (DCMs)
32 Mbit Intel Strata Flash
 * 3 numbers of 20 pin header to interface VLSI based
experiment modules
 8 input Dip Switches
 * 8 output Light Emitting Diodes (LEDs)
 * On Board programmable oscillator (3 to 200 MHz)
15

16. 16x2 Alphanumeric LCD
* RS232 UART
* 4 Channel 8 Bit I2C based ADC & single Channel DAC
* PS/2 Keyboard/Mouse
* Prototyping area for user applications
* On Board configuration flash PROM XCF01S
16

17.  Opto coupler is used to isolate the control circuit
from power circuit.
 An Driver circuit is designed to connect the gate
directly to a voltage bus with no intervening
resistance other than the impedance of the driver
circuit switch.
 Gate driver acts as a high-power buffer stage
between the PWM output of the control device and
gates of the primary switching MOSFET (or) IGBT.
17

18.  Isolate the control circuit from power circuit.
 The 6N137 consist of a high emitting diode and a one chip
photo IC. This unit is 8−lead DIP package.
 Pin Details
 1 : N.C.
2 : Anode
 3 : Cathode
 4 : N.C.
 5 : GND
 6 : Output(Open collector)
 7 : Enable
 8 : VCC
18

19. 19

20. 20
+15V
0
+15V
+15V
+15V
+15V
+15V
S2'
G2'
S1'
G1'
S4'
S3'
G3'
G4'
PWMInput3'
8
7
5
3
2
6
20k
PWMInput4'
8
7
5
3
2
6
U1
IR2110
1
7
10
11
12
13
2
6
3
9
5
LO
HO
HIN
SHDN
LIN
VSS
COM
VB
VCC
VDD
VS
18V2
10k
U2B
4584
3 4
147
20k
20K
0.1uF
1
20.1uF
1
2
10uf/63V4
10k
20k1
20k
PWMInput1'
8
7
5
3
2
6
20K2
20k1
4.7k
4.70k
20K
PWMInput2'
8
7
5
3
2
6
10k
10uF/63V
.01u
1 2
U2A
4584
1 2
147
FR107
U2B
4584
3 4
147
18V2
18V
20k
U1
IR2110
1
7
10
11
12
13
2
6
3
9
5
LO
HO
HIN
SHDN
LIN
VSS
COM
VB
VCC
VDD
VS
FR107
20k
10uf/63V
0.1uF
1
2
10k
0.1uF
1
2
20k
18V
18V
10uf/63V4
20K2 18V
FR107
U2A
4584
1 2
147
FR107
10uf/63V
4.70k
4.7k
4506
4506

21. 21

22.  Single Phase Cascaded Nine Level Inverter with
Sinusoidal Pulse Width Modulation (SPWM)
technique is implemented by using FPGA controller.
 It consists of four full bridge inverters connected in
series on the AC output side.
 Each bridge can create three different voltage
levels (+Vdc,0,-Vdc) in ac output allowing an
overall nine level ac output voltage.
22

23. 23

24.  It is used to supply dc output voltage to the Inverter and FPGA driver
circuit.
 RATINGS
Primary Voltage = 230v AC
Secondary Voltage = 0-9 v AC and 15-0-15v AC
Regulator
IC - 7805 and 7812 = Positive Voltage Regulator (+5v and
+15v).
IC - 7812 = Negative Voltage Regulator (-15v)
Diode = 1N4007
Capacitor = 4700µf/16v,4700µf/25v and 10µf/63v
24

25. 25

26. 26

27. 27

28. 28
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
T13
T14
T15
T16

29. 29

30. 30

31. 31

32. 32
MI RMS
voltage
FRQ
(Hz)
THD P-P (+)
voltage
(-)
voltage
MAX
voltage
AVG
voltage
100 16.4 49.71 0.0 +24.4 -23.6 17.9 16.3
99 16.0 49.28 0.0 23.6 -23.3 16.6 16.0
98 16.1 48.73 0.0 24.0 -24.0 16.6 15.9
97 15.7 48.54 2.9 23.2 23.0 16.7 15.7
96 15.71 47.81 4.0 23.6 23.6 16.7 15.6
95 15.4 47.33 4.3 24.0 23.6 15.9 15.4
94 15.2 46.93 5.8 24.0 23.3 16.7 15.3
93 15.0 46.50 7.4 23.3 22.6 15.7 15.3
92 15.0 45.85 4.7 23.3 22.6 15.6 14.9
91 14.7 45.42 4.3 23.6 23.0 15.9 15.0
OUTPUTS OF CASCADED NINE LEVEL INVERTER

33. 33
90 14.6 44.81 3.9 24.4 23.6 16.7 14.7
89 14.4 44.21 3.3 23.3 22.0 15.7 14.4
88 14.3 43.79 3.7 23.3 22.3 15.7 14.2
87 14.1 43.45 3.4 23.3 21.6 16.1 14.1
86 13.9 42.90 3.4 24.4 22.0 16.1 14.0
85 13.8 42.32 3.8 23.0 22.0 16.1 13.7
84 13.6 47.91 3.8 23 21.3 16.1 13.7
83 13.7 41.47 4.2 24.7 22.3 16.8 13.6
82 13.3 40.97 4.7 22.0 20.6 16.1 13.2
81 13.2 40.30 4.5 20.0 20.6 16.1 13.2
80 12.0 0.0 0.0 21.3 20.3 0.0 12.9

34. 34

35. 35

36. 36
TOTAL HARMONIC DISTORTION OUTPUT WITH 5.8%

37.  The performance of multilevel inverter (MLI) with
fundamental and PWM switching schemes are
studied through simulation using Matlab/Simulink.
 It is observed that for Nine Level Multilevel Inverter,
the THD is less in the case of PWM switching
scheme. It is further identified that fundamental
switching scheme gives better performance as the
number of levels increases.
37

38.  B,shanthi,natarajan.S.P,” fpga based fuzzy logic control for single phase
multilevel inverter”,international journal of computer applications(0975-8887)
volume 9- n0:3,november 2010.
 Azli, N.A. and Ning W.S. 2004 Application of Fuzzy Logic in Regulating a
Multilevel Inverter output. In:Proceedings of 2004 International Conference on
Power System Technolpgy, Singapore, 21-24.
 Azli, N.A. and Wong, S.N. 2005 Development of a DSP based Fuzzy PI
Controller for an Online Optimal PWM Control Scheme for a Multilevel Inverter.
In: Proceedings of IEEE International Conference on Power Electronics and
Drive Systems PEDS’05, 1457-1461.
 Carrara, G. and Gardella, S., Marchesoni M.,Salutari R., Sciutto G.. A New
Multilevel PWM Method: A Theoretical Analysis. In: IEEE Trans. Power Electron,
July 1992, Vol. 7, 497–505.
 Yan Deng, Hongyan Wang, Chao Zhang, Lei Hu and Xiangning He. 2005
Multilevel PWM Methods Based on Control Degrees of Freedom Combination
and its Theoretical Analysis. In: Proceedings of the IEEE IAS Conference
Record no.: 0-7803-9208-6 /05, 1692 – 1699
38

39. 39