Modular Solar Grid Tie Inverter - BuckBoost Power Conversion Module - Platform for creating and sharing projects

Tested input voltage range is 110 - 300 VDC from solar panel chain/batteries, additional external blocking capacitors are required. Output power for constant control voltage varies slightly with input voltage changes, roughly 0,08% variance per volt of change.

Output of this module is designed to feed into a separate unfolding H-bridge/4Q rectifier/polarity switch module which is connected to 230/240 V power grid (designed in mind with voltage range of 209 - 253 Vrms). Output can supply current only into positive voltage loads, negative voltages (eg. from direct grid connection) will destroy the module!

Grid Tie operation works on the principle of emulating negative resistance, so when input control voltage is kept constant the output power rises with the second power of the output (grid) voltage.

Power control is implemented via frequency modulating the 9910 IC with external control voltage/control current. Over temperature protection is implemented by offseting the input power sensitivity with a NTC thermistor. For module with both heatsinks and ambient temperature of around 22 °C the continuous output power is thermally limited to roughly 128W with 91 % conversion efficiency. Higher ambient temperatures mean lower output power limit, active cooling allows for even more power.

Module requires a M1.4 2mm long self tapping screw with M2 spring lock washer and M1.6x4x0.3 flat washer to create an electric connection to the aluminum substrate via X1.

Heatsinks used are usually found as "heatsink black 40x40x11mm" on aliexpress etc.

3D printed box should be made from ABS of other high temperature resistant material.

Mosfet can be basically any power mosfet capable of handling at least 650 V and with RDSON bellow 0,5 ohm.

Film capacitors are orignally THT, they need to be modified to allow SMD mounting by bending and shaping their leads as in the following photo.