Week4 by HadeedAhmedSher on Scribd
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EE-211| Week1- FEE GIKI
Solar PV cells are the smallest unit in a PV panel. These are low power output units and hence in order to produce a reasonable output from them, several cells are connected in series and parallel configurations. In a series and parallel configuration, we use to add a bypass diode that prevents the sinking of a group of cells in case of shading. This blocking diode is always connected across a group of cells because of two reasons. First, no ideal diode exists which means that diodes need to overcome a potential difference to work. Secondly, in a single cell, it is very difficult to forward bias the diode because of very low output voltage levels.
In this blog, i simulated the lectures of Prof. L Umanand about the design of PV systems. This is to facilitate the fellows who are not working on Linux.
Figure 1 shows the schematic. Figure 2 shows the results under uniform irradiation conditions and figure 3 shows the results for partial shading across module 1.
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| Figure 1 : Schematic. PV module consists of 5 X 2 cells |
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| Figure 2: Under uniform irradiance condition |
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| Figure 3 : Partial shading on three cells of module 1. |
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| Figure 4. Code for PSPICE |
***************************************************************************
cell to module
Ip11 0 1 DC 1 ;Cell 1 module 1
Rsh11 0 1 100000
Rs11 1 2 0.1
D11 1 0 Def
Ip12 2 3 DC 1 ;Cell 2 Module 1
Rsh12 2 3 100000
Rs12 3 4 0.1
D12 3 2 Def
Ip13 4 5 DC 0.7 ;Cell 3 Module 1
Rsh13 4 5 100000
Rs13 5 6 0.1
D13 5 4 Def
Ip14 6 7 DC 0.7 ;Cell 4 Module 1
Rsh14 6 7 100000
Rs14 7 8 0.1
D14 7 6 Def
Ip15 8 9 DC 0.7 ;Cell 5 Module 1
Rsh15 8 9 100000
Rs15 9 20 0.1
D15 9 8 Def
Ip21 20 10 DC 1 ;Cell 1 Module 2
Rsh21 20 10 100000
Rs21 10 11 0.1
D21 10 20 Def
Ip22 11 12 DC 1 ;Cell 2 Module 2
Rsh22 11 12 100000
Rs22 12 13 0.1
D22 12 11 Def
Ip23 13 14 DC 1 ;Cell 3 Module 2
Rsh23 13 14 100000
Rs23 14 15 0.1
D23 14 13 Def
Ip24 15 16 DC 1 ;Cell 4 Module 2
Rsh24 15 16 100000
Rs24 16 17 0.1
D24 16 15 Def
Ip25 17 18 DC 1 ;Cell 5 Module 2
Rsh25 17 18 100000
Rs25 18 19 0.1
D25 18 17 Def
Vx 19 21 DC 0 ; Combined output current measurement
Vo 21 0 SIN(0 8.5 50 0 0 0) ;To sweep the output
Dbp 0 20 Def ; bypass didoe
.model Def D
.tran 0.01m 4.5m
.Probe
.end
*****************************************************************************
In PSPICE plotting is not based on programming like that in MATLAB. In fact, the plotting is based on the set of variables that can be selected for x and y axis. The problem, however, is that if you want to plot two curves with different ranges of x axis variables. I spent quite a time on solving this issue. Although I did not reach where I wanted to land, however, i found one solution but first, let me introduce you to the circuit i wanted to simulate.
The figure above shows two PV cells connected in series with each other. The combined output is taken from the node 3 and 5. I want to draw the I-V curves of both the cells as well as their combined output. However, in order to do so if I select the x axis as the voltage V3 the I-V curve for the individual cells is compromised and if I select the x axis as V3-V1 then the I-V curve of combined cells is compromised. To solve this I selected two plots and unsynchronized their x axis as shown in the figure below. To unsyncronize the x axis click on plot > unsynchronize x axis.
The next challenge is to plot them on one plot.
The next challenge is to plot them on one plot.