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CCS/TIDM-SOLARUINV: Solar Micro-inverter State machine

Part Number: TIDM-SOLARUINV

Tool/software: Code Composer Studio

Hi, I am testing the state machine for grid connection with the solar micro inverter and I having some problems with some states. When the micro inverter board is in Idle state and I give an Gui_InvStart = 1; while there is nothing connected to the PV terminals, the board gets into the MonitorDCBus state. I don´t know why it is getting into that state, because it should stay in CheckPV state. Even, if I force PVInverterState to CheckGrid state, it jumps to MonitorDCBus state again. The readings that I am getting on GUI-Vpv are almost 0 Volt and the value of VPV_MIN defined in the header is 15V. Also, I have tried to put a wire between PV+ and PV- to eliminate induced voltages, but it dind´t work.

From the program It is like the condition Gui_Vpv>VPV_MIN is always true, but the values of GUI-Vpv are almost 0v.

if(Gui_Vpv>VPV_MIN)
            {
                // sufficient PV voltage is present
                // Clear Fly Back Trip and monitor DC BUs
                PVInverterState=MonitorDCBus;

The board is tested with an insulated power supply and It is powered by the internal bias power supply. It is connected to a 220V 50HZ grid with build = 3.

The other doubt that I have is why there are not flags for under or over frequency. The code is commented. It is not relevant to check the grid frequency?

Thank you!

Diego

  • Diego,

    If you don;t have any high voltages present, you can set a hardware break point and debug the code to see if it is taking the correct path ..

    Have you tried doing that??? (make sure you don;t have high power when doing this type of debug)

    You can potentially un-comment that code, we were getting spurious trips and hence the code was commented out.

    We subsequently solved the issue, but have not had a change to release the code, it will not happen this year.. so you will have to implement this part and test it on your own.

    -Manish