VI-Scanner

For the second algorithm to be tested in this work, the shadow management of modern MPP trackers is to be implemented. Thereby the IU-characteristic of the solar module is scanned quickly in an interval of several minutes and it is checked at which point the maximum power can be drawn. This operating point is then set for the next interval.

The code in VI scanner loop uses two loops to find the maximum power point of the PV-module. It increments the duty cycle of the device from 0% to 70% and measures the voltage, current, and power of the device. When the voltage $U_{pv}$ on the solar module drops below $12V$, the recording is stopped. The reason for this is that the gate driver cannot drive the mosfet anymore because the operating voltage is too low. The measured values are stored in a list and the maximum power point is determined based on the collected data. Finally, the duty cycle is set to the value of the maximum power point and the program waits 60 seconds before starting over. The waiting time can be configured as required to keep the module optimizer at this point for longer.

VI Scanner loop

power_curve =[]
while(True):
    for duty in range(70):
        device.setDutyCycle(duty)
        time.sleep_ms(20)
        device.getfilteredADC()
        device.calcADCData()
        time.sleep_ms(20)
        power_curve.append(device.power[0])
        device.printOut()
        if device.voltage[0] < 12:
            print('Abbruch ', device.voltage[0])
            break
    power_max = max(power_curve)
    duty_max = power_curve.index(power_max)
    power_curve.clear()
    device.setDutyCycle(duty_max)
    time.sleep_ms(100)
    device.getfilteredADC()
    device.calcADCData()
    time.sleep(60)