My project is to deliver the output of 200w solar panel (40v,1.5A)- very low because I am using lamps instead of the sun- to a load at a voltage level of 100v, after implementing the design of my boost circuit (L of 4.4 mH, C of 220 uF, IRF510 as a switch gate driven by a PWM of 10v amplitude to have the maximum current rating of MOSFET) the output of the boost still at the same level of the input (no stepping up!). I'm not sure what is my mistake,by the way the output of my arduino is only one wire connected directly to the gate of the MOSFET I didn't referance the GND of the arduino to the -ve side of the system main flow. is my calculation to the inductance and the capacitance values correct?

here's a drawing of the systementer image description here Please show me what should I correct

Thanks and regards

  • \$\begingroup\$ As Andy says, boosts have no real current limit. If the FET doesn't switch at all, current will still flow from the input through the inductor and diode into the load. \$\endgroup\$
    – gsills
    Commented Apr 16, 2015 at 22:28
  • \$\begingroup\$ Lamps will be almost useless unless strong and close. Multiple high wattage halogen lamps so close to the panels that the panels are at 40 degrees C plus are needed to simulate sunlight. Or, to get 40W of equivalent sunlight you'd need 100 to 200 Watts of LED lighting with all light on panels evenly. USE SUNLIGHT. \$\endgroup\$
    – Russell McMahon
    Commented Apr 17, 2015 at 1:14

1 Answer 1


You need a ground connection between 0V of the arduino and the source of the MOSFET - there is no arguament about this - it won't work without it.

Also how can your sensors be measuring current - something is needed in series with the wires coming from the solar panel (or a hall effect sensor).

When you do connect the ground start with the smallest duty cycle you can because, with no load you'll just get a massive voltage at the step-up point and make a mess of the output capacitors.

Each cycle of on-off of the FET transfers an amount of energy to the output and this might be (off the top of my head) an energy of about 50 uJ. This energy will lift the 220uF output capacitor 0.5 volts (ish) per cycle. You don't need to be clever to understand that a 100V is reached in a very short period of time and, without control this will continue until the MOSFET fries on over-voltage.

If you want, put a dummy load on to simulate the real load.

  • \$\begingroup\$ yes the sensors are ok and working both and their values are input to do the P&O method of MPPT and duty cycle is changing after that. I didn't connect the GND of arduino to the source of irf510 becaue i thought it will be high ratings to handle for arduino and it will burn \$\endgroup\$
    – John Am
    Commented Apr 16, 2015 at 18:58
  • \$\begingroup\$ but the MOSFET is a power mosfet which in the datasheet Vds can be 100v which the maximum I would get. can you please clear it more \$\endgroup\$
    – John Am
    Commented Apr 16, 2015 at 19:12
  • 1
    \$\begingroup\$ A 100 volt mosfet is not good enough for a 100V booster - something like 150V is a minimum. \$\endgroup\$
    – Andy aka
    Commented Apr 16, 2015 at 20:15
  • \$\begingroup\$ thank you so much, I will try to get a new model, but what about the inductance and capacitor values because I'm having troubles what formula should I use to my design \$\endgroup\$
    – John Am
    Commented Apr 16, 2015 at 20:18
  • \$\begingroup\$ See my answer from here: electronics.stackexchange.com/questions/161886/… \$\endgroup\$
    – Andy aka
    Commented Apr 16, 2015 at 20:23

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