V-I Characteristics of PV Emulator in Solar Explorer Kit

Hi Arpan,

The above curve seems more like a temperature variation based curve instead of irr. variation.Something like this:

Regards,

Gautam

In this manual, they are indicating that the voltage varies proportionately to irradiance

Arpan,

the idea behind the PV emulator on the solar explorer kit was to give a quick demo with some sort of PV characteristics implemented in the emulator. 

We used a basic curve and then just linearly scaled it based on luminance, and did not modify it with complete non linear characteristics that a panel will show under varying lighting conditions. 

The control scheme does not change irrespective of PV characteristics in the emulator. Which is the primary focus of the kit.

The aim was not to provide a PV emulator reference  design. The source code is available in controlSUITE and you can modify based on what you need for your application.  

 But as its named PV Emulator, it should emulate the characteristics as much as possible ! It does hinder some experiments which involve change of irradiation ! Now I will have to spend time coding instead of performing experiments.
I want to add that this whole kit seems very slipshod . Ill designed hardware and the codes given in the control suite folder don't work by default. All of them have to be debugged and minor problems weeded out.
Its quite disappointing and not of the quality expected from TI.

And I want to add that I don't use internet as a means of venting frustration and generally avoid online criticism.

I, like Arpan, would like to modify the I-V lookup table in the software, but I can't for the life of me find which file contains it. Please could you be more specific about where it is located? Thanks.

Susan,

Please import the following project

C:\ti\controlSUITE\development_kits\SolarExplorer_v1.1\SolarExplorer_PVEmulator_F2802x

You would see a PV_Table1.asm which is a current referenced voltage set command look up table, there is only one table  being used, for the illumination this table is simple scaled by a gain factor. 

It is read in the ISR, refer to the DPL-ISR.asm file

MOV @AR0,AH 

.ref _PVTablePtr
MOVW DP,#_PVTablePtr
MOVL XAR1,@_PVTablePtr
MOV AL,*+XAR1[AR0]

.ref _Value_Asm
MOVW DP,#_Value_Asm
MOV @_Value_Asm, AL

MOVL ACC,@_Value_Asm
LSL ACC,#16
MOVL XT,@ACC

.ref _Vout_Ref_Asm
.ref _VmaxSenseInv
MOVW DP,#(_VmaxSenseInv)
QMPYL ACC,XT,@_VmaxSenseInv

I figured out how you can do it using C code, just forget about the .asm file.
Type your equations (or lookup table) in the main.c file, then connect whichever variable contains the reference output voltage value to the MATH_EMAVG block, replacing  "MATH_EMAVG_In1=&Vout_Ref_Asm_Lum;"  with  "MATH_EMAVG_In1=&YOUR_VARIABLE;". You should find it easily searching for that line using ctrl+F.

Reminder: that variable must contain the reference output voltage divided by 33.3, so its range is from 0 to 1.