My present PV installation suffers quite a bit of shading being a ground mount close to obstacles (better than anywhere else & roof unsuitable), so quite a bit of the day was being spent at low power (<50W) as a result. This being a series connected string suffers from false power humps under such conditions as illustrated by the example plot below. The size and number of such humps is dependent upon the particular shading shape.
Many including my implementation of MPPT will lock onto the minor lower powered hump further up the voltage scale than the actual true maximum power point at a lower voltage. To address this problem I introduced a voltage sweep into the inverter software every 10 minutes to search out the true maximum power peak and pass this to the normal MPPT software as a starting point.
To enable me to monitor operation from my desk instead of a freezing garage I used an ESP8266 to provide a WIFI web server delivering voltage and power to a Java script loaded to the client web-browser to produce plots, in this way I can monitor performance in realtime. The screenshot below shows typical operation with the "spikes" being the new scanning software. As yet the weather is poor so I have not been able to see the improvement with shadows.
Many including my implementation of MPPT will lock onto the minor lower powered hump further up the voltage scale than the actual true maximum power point at a lower voltage. To address this problem I introduced a voltage sweep into the inverter software every 10 minutes to search out the true maximum power peak and pass this to the normal MPPT software as a starting point.
To enable me to monitor operation from my desk instead of a freezing garage I used an ESP8266 to provide a WIFI web server delivering voltage and power to a Java script loaded to the client web-browser to produce plots, in this way I can monitor performance in realtime. The screenshot below shows typical operation with the "spikes" being the new scanning software. As yet the weather is poor so I have not been able to see the improvement with shadows.
