0 1 00:00:05,220 --> 00:00:06,570 Hi everyone. 1 2 00:00:06,570 --> 00:00:08,320 Welcome back to PV 2 3 00:00:08,330 --> 00:00:13,920 solar energy course into the last section. 3 4 00:00:13,980 --> 00:00:23,690 We already discussed that electric behavior of solar cell and light and dark and we discovered that 4 5 00:00:24,380 --> 00:00:34,800 the idea of solar cell may be modeled by a current source in parallel with a diode to understand 5 6 00:00:34,840 --> 00:00:38,080 mean parameter of solar cell. 6 7 00:00:38,150 --> 00:00:47,300 We are going to simplify this circuit by eliminating the shunt resistant and series resistant as shown 7 8 00:00:47,630 --> 00:00:49,750 in the right figure. 8 9 00:00:53,190 --> 00:00:59,930 The diode current can be model as Id equal to. 9 10 00:01:00,510 --> 00:01:10,250 I note which is that saturated current or reverse saturated current or leakage saturated 10 11 00:01:10,250 --> 00:01:21,920 current times exponential of Q which is electronic charge times the voltage. 11 12 00:01:22,170 --> 00:01:33,660 Above all this meant constant time Zeldin preacher all minus one mean that our current will be equal 12 13 00:01:33,670 --> 00:01:42,370 to I for two of the current source minus diet current which is equal. 13 14 00:01:42,630 --> 00:01:53,710 I knew times exponential of electric charge times the voltage over both these men cause sometimes temperature 14 15 00:01:54,100 --> 00:02:11,380 minus one we can rule this equation as a function of current involved the only variable Z is the voltage. 15 16 00:02:11,380 --> 00:02:18,370 So when the voltage is change the current will be changing. 16 17 00:02:18,930 --> 00:02:20,270 As shown in the circuit 17 18 00:02:24,380 --> 00:02:32,840 in this plot we are going to discuss the external parameter zapped it through minus a light to electricity 18 19 00:02:32,840 --> 00:02:40,290 conversion efficiency of idea a solar cell let's start with open circuit voltage. 19 20 00:02:40,810 --> 00:02:48,900 Let's consider a z z determinant of an illuminated solar cell are not connected. 20 21 00:02:50,850 --> 00:02:58,680 In this situation it's called an open circuit an open circuit the solar cell doesn't produce any current 21 22 00:02:59,430 --> 00:03:02,430 and slowly produce a voltage. 22 23 00:03:02,520 --> 00:03:09,580 This full dish is called the open circuit voltage zoom voltage is easily recognized. 23 24 00:03:09,760 --> 00:03:11,670 Is that all you V. 24 25 00:03:11,690 --> 00:03:23,840 Plot by intersection of I V curve with Zella Rosenthal axis corresponding to the current equal to zero 25 26 00:03:24,720 --> 00:03:35,870 as shown in this figure we can derive a simple equation for open circuit voltage of an idea. 26 27 00:03:35,890 --> 00:03:36,620 Solar Cell 27 28 00:03:39,610 --> 00:03:42,610 other open circuit condition. 28 29 00:03:42,830 --> 00:03:45,290 The current is equal to zero. 29 30 00:03:46,790 --> 00:03:56,830 If we solve this equation we arrive at a simple expression for the open circuit voltage. 30 31 00:03:56,910 --> 00:04:03,780 It is linear with both these men constant times temperature divided boy. 31 32 00:04:03,820 --> 00:04:14,500 The charge of electron and its linear with the natural logarithm of the ratio between the photo Qana 32 33 00:04:15,190 --> 00:04:18,490 and the linkage current the loss 1 33 34 00:04:22,820 --> 00:04:32,450 equation shows that the amount circuit floater depends on several barometer firstly the open circuit 34 35 00:04:32,450 --> 00:04:34,660 voltage depends on two preacher 35 36 00:04:37,880 --> 00:04:48,170 secondly the equation shows that ends up food the current density is increased the open circuit voltage 36 37 00:04:48,200 --> 00:04:50,270 is increased as well. 37 38 00:04:50,300 --> 00:05:00,240 This means that by increasing the irradiation or in other words by shining the light on solar cell zob 38 39 00:05:00,300 --> 00:05:07,960 in circuit voltage can be increased. 39 40 00:05:08,000 --> 00:05:17,910 Also this equation 1 First I suggest Z open circuit voltage increase with temperature. 40 41 00:05:17,920 --> 00:05:31,050 This is not a case the latest torrent or on a note of diet strongly depend on the temperature means 41 42 00:05:31,380 --> 00:05:35,660 the highest in preacher the larger Lake is traversed since you're 80. 42 43 00:05:35,670 --> 00:05:46,630 Current and smaller over the circuit voltage will be mean there are always circuit voltage depends on 43 44 00:05:46,690 --> 00:05:47,970 other factors. 44 45 00:05:50,780 --> 00:06:05,530 Such as the band again of absorber material as an amount of dubbing of Z don't leave that wanted host 45 46 00:06:05,530 --> 00:06:16,560 the material Xilai generated condensed and anti-immigration and we already understood Z him preacher 46 47 00:06:17,670 --> 00:06:26,100 is inversely proportional to the open circuit voltage we already understood the open circuit voltage 47 48 00:06:26,790 --> 00:06:36,770 is inversely proportional to sit in preacher the second parameter we are going to discuss they is short 48 49 00:06:36,770 --> 00:06:47,350 circuit current if we short circuit all terminal of Z solar cell Z eliminate the solar cell will slowly 49 50 00:06:47,350 --> 00:06:58,210 produce a current and will produce no voltage this current density is called the Short Circuit Ga. 50 51 00:06:58,260 --> 00:06:58,680 This 51 52 00:07:04,920 --> 00:07:14,800 the short circuit current can easily be recognized in the I.V. care as well it is the intersection between 52 53 00:07:14,800 --> 00:07:21,020 the vertical line corresponding to zero voltage and so on V curve 53 54 00:07:24,980 --> 00:07:33,830 we can derive a simple equation forces a short circuit garden density or shorter type of an ideal solar 54 55 00:07:33,830 --> 00:07:39,560 cell by using again as the expression of the joy of your relationship 55 56 00:07:42,620 --> 00:07:52,870 ie equal to eye food to current minus i.e. die you when the vote is equal to zero mean the auto short 56 57 00:07:52,860 --> 00:08:00,930 circuit will be equal to I photographed means if we take a voltage equal to zero. 57 58 00:08:01,000 --> 00:08:05,470 The short circuit current is if were the two therefore two current 58 59 00:08:09,450 --> 00:08:20,460 the short circuit current debates on several fact like say in single light it just or the number of 59 60 00:08:20,460 --> 00:08:25,440 floaters falling on Z solar cell. 60 61 00:08:25,460 --> 00:08:29,030 Second thing is this big turn of the light 61 62 00:08:32,140 --> 00:08:45,340 sensing is optical properties or absorption coefficient so let's think is collection probability. 62 63 00:08:45,580 --> 00:08:53,530 Now we already understood the meaning of short circuit count and the open circuit voltage all open circuit 63 64 00:08:53,530 --> 00:09:05,550 voltage is the maximum voltage on the solar cell and short circuit term is the maximum con can be produced 64 65 00:09:05,730 --> 00:09:17,300 by solar cell tomorrow we are going to introduce you to an important properties of solar cell which 65 66 00:09:17,300 --> 00:09:31,140 is maximum power point which is the main principle of the maximum our point trucker so see you in the 66 67 00:09:31,130 --> 00:09:32,150 next to block.