Ea Elektro Automatik EA Elektro-Automatik 06230319, 1 Output Variable DC Power Supply, , Bench 06230319 Hoja De Datos

Page 73

EA Elektro-Automatik GmbH

Helmholtzstr. 31-33 • 41747 Viersen

Germany

Fon: +49 2162 / 3785-0

Fax: +49 2162 / 16230

3.9.13.1  Preface
This function uses the standard XY generator to make the power supply simulate 

solar panels or solar cells with certain characteristics. The device calculates 

an IU table from four typical values. 
While the function is running, the user can adjust a parameter “Irradiance” 

between 0% (darkness) and 100% (bright light) in 1% steps to simulate differ-

ent light situations. 
The most important characteristics of a solar cell are:
•  the short-circuit current (I

SC

), which is proportional to the irradiance

•  the open circuit voltage (U

OC

), which almost reaches its maximum value 

even in low light situations

•  the maximum power point (MPP), at which the solar panel can provide the 

maximum output power

The voltage of the MPP (here: U

MPP

) lies typically 20% below U

OC

, the current 

of the MPP (here: I

MPP

) lies typically 5% below I

SC

. In case there are no definite 

values for the simulated solar cell available, Impp and Umpp can be set to this 

rule of thumb. The device limits the I

MPP

 value to I

SC

 as upper limit, the same 

applies for U

MPP

 and U

OC

.

3.9.13.3  Usage
In the PV table function, which is based upon the XY generator with IU characteristics, the MPP is defined by the 

two adjustable parameters Umpp and Impp (also see diagram below). These parameters are usually stated in data 

sheets of solar panels and have to be entered here.
The following parameters can be set for the PV table function:

Uoc

Umpp...Nominal device voltage Open circuit voltage at no load

Isc

Impp...Nominal device current

Short-circuit current at max. load and low voltage

Umpp

0 V...Uoc

DC output voltage at the MPP

Impp

0 A...Isc

DC output current at the MPP

Schematic diagram:

Application and result:

Adjust all four parameters on screen to the desired values. Whether the 

calculated IU and P curves, which result from those values, make sense or 

not can be verified with a tool (Excel table or small software), which is either 

included with the device on CD or can be obtained upon request. The tool 

visualises the curves as calculated from the adjusted values.
While the simulation is running, the user can see from the actual values 

(voltage, current, power) of the DC output, where the operating point of the 

power supply resp. of the simulated solar panel is. The adjustable value 

radiance (0%...100% in 1% steps, see screenshot below) helps to simulate 

different light situations from darkness (no power output) to the minimal 

amount of light that is required to make the panel provide full power.