In solar energy systems, inverters are very important components. If the solar inverter fails, the solar system will also fail to work.

Firstly, we need to investigate these situations

1. Overcurrent

2. Overvoltage

3. Thermal Failure

4. Insects Entering the solar Inverter and Causing Short Circuits on the Circuit Board

5. Solar Panel Voltage Exceeds MPPT controller Input Range

1. Overcurrent

Causes: Load short circuit, motor stalling, accidental output short circuit, etc., causing current to exceed MOSFET ratings.

Checkpoints:

Measure load current for abnormalities. Inspect output terminals for short circuits or insulation damage.

2. Overvoltage

Causes: Sudden input voltage spikes (e.g., grid surges, lightning strikes). Back electromotive force (EMF) from inductive loads (e.g., motors) during shutdown.

Checkpoints: Check whether there is lightning strike or grid surge in the area

3. Thermal Failure

Causes: The inverter's air outlet is obstructed by the wall, resulting in ineffective heat dissipation.

Checkpoints:

Inspect the installation location of the inverter to ensure sufficient space (typically recommended at least 20-30 cm) between the air outlet and the wall or other obstacles. Ensure that the air intake and outlet are not obstructed, allowing air to circulate freely.

4. Insects Entering the solar Inverter and Causing Short Circuits on the Circuit Board

Checkpionts: Open the inverter casing and inspect the interior for the presence of insects, eggs, or secretions.

Check the circuit board for signs of short circuits (e.g., burnt traces or components).

5. Solar Panel Voltage Exceeds MPPT controller Input Range

Causes: Excessive series connection of solar panels, causing total voltage to exceed the mppt controller’s maximum input voltage.

Inverter MPPT (Maximum Power Point Tracking) circuit cannot adapt to voltage fluctuations, leading to internal overvoltage.

Checkpoints:

Verify if the voltage of the series-connected solar panels is within the inverter's rated input range. For example, 10kw solar system with 12pcs solar panels, 3pcs panels in series, the pv input voltage will not higher than 150V. ( use multimeter to test the PV combiner input and output terminal voltage )