Hello, dear friend, you can consult us at any time if you have any questions, add WeChat: THEend8_
EEET 3050 - Renewable Energy Systems
Practical 4 - Characteristic of PV Cells with Series and Parallel Resistances
Aim: The aim of this practical is to evaluate the I-V characteristics of a PV cell with (i) series resistance, and (ii) series and parallel resistance
using Matlab/Simulink block diagram.
Objectives: Develop the model of a PV cell with a series resistance
Develop a more realistic model of a PV cell considering both parallel and series resistances
In Practical 03, the impact of the parallel resistor on the PV cell characteristics was studied. The PV cell illustrated in Fig. 1 can be
further modified by including a series resistance. Some of this might be contact resistance associated
with the bond between the cell and its wire leads, and some might be due to the resistance of the semiconductor itself.
Fig. 2 illustrates a PV equivalent circuit that includes series resistance RS. The ideal current source ISC in this case delivers current
to the diode:
I = (Isc − ID )
Impact of the series resistance can be added as follows:
VD = V + I ∗ Rs
Hence,
I = Isc − Io {(e38.9∗(V+I∗RS) ) − 1}
Above equation can be interpreted as the original I -V curve with the voltage at any given current shifted to the left by ∆V = I ∗
Rs as shown in Fig. 3.
Fig. 2 The PV cell equivalent circuit with series resistance
Fig. 3 Modifying the simplified PV cell equivalent circuit by adding series resistance causes the voltage at any given current
to shift to the left by IRS.
Exercise 1
Fig.2 illustrates the circuit model of a PV cell with the series resistance and Fig. 4 illustrates the corresponding Simulink model block diagra
In order to study the impact of the series resistance of the PV cell, you will be developing both simplified PV cell, and the PV cell with RS
in the same MATLAB/SIMULINK model and comparing the results by plotting the graphs.
Fig.4 Model block diagram of the simplified PV cell with and without RS resistance in Simulink
Instructions
1. Open MATLAB from ‘Start’ menu.
2. Open the Simulink file “CharacteristicsPV” you saved in Exercise 1. “Save As” the file with the name “CharacteristicsPV_Rs” .
3. Click ‘Simulink Library’ icon in the toolbar to get the window of the Simulink library.
4. Search for the following blocks and drag & drop them into your Simulink file.
• Product, sum, XY graph, simout (To Workspace), mux, gain, constant, repeating sequence, Fcn
5. Keep the simplified PV cell model you build from the previous Exercise.
6. Double click on the “Mux” and enter the number of inputs as 6.
7. Delete the unnecessary connections in the model.
8. Connect all the elements as in Fig. 4.
9. Double click on the “Constant” block and enter ‘1000’ .
10. Double click on the gain and enter ‘1/250’ .
11. Double click on the ‘Sum’ block and enter -+|
12. Double click on the ‘Fcn’ block and enter ‘ 1e-9*(exp(38.9*u)-1)’ .
13. Double click on the ‘Repeating sequence’ and enter the following parameters:
• Time values – [ 0 1 2],Output values – [-0.1 0.6 -0.1]
14. Double click on the ‘I-V Characteristics ideal’ XY scope and enter the following parameters:
• Xmin – 0, Xmax – 0.6, Ymin – 0, Ymax – 5.0
15. Double click on the ‘PV power ideal’ XY scope and enter the following parameters:
• Xmin – 0, Xmax – 0.6, Ymin – 0, Ymax – 2.0