Photovoltaic inverter current limiting operation

How to ensure maximum exploitation of the inverter capacity?

To provide overcurrent limitation as well as to ensure maximum exploitation of the inverter capacity the performance of the proposed control strategy, is evaluated as per the three generation scenarios given below: In this case, the inverter’s capacity is majorly exploited through the injection of active power under normal operating condition.

How does a photovoltaic system work in power limit mode?

The PV works in power limit mode, and the output current of the PV is reduced by controlling the boost converter. According to the photovoltaic I–V characteristic curve, the output voltage of the PV increases as a result and moves further away from the maximum power point.

What is the use of bus voltage in a photovoltaic inverter?

The increase in bus voltage is used as the control signal of the PV output current to reduce the photovoltaic output current, such that the PV output power is reduced from 3000 W to the inverter power limit value of 1500 W, which meets the requirements of the inverter output power limit.

Does a two-phase and three-phase dip in grid voltage limit inverter current?

The results under two-phase and three-phase dip in the grid voltage shows that the proposed control strategy injects maximum reactive and active power and limits the inverter current by quickly activating the APC control loop during fault-ride-through period.

How to provide voltage support in PV inverter?

To provide voltage support at the PCC, reactive power is injected into the grid under fault conditions as per the specified grid codes. As previously discussed, the simultaneous injection of peak active power from PVs and reactive power into the grid for voltage support can trigger the over current protection mechanism in PV inverter.

What are the goals of grid-connected PV inverters?

Under grid voltage sags, over current protection and exploiting the maximum capacity of the inverter are the two main goals of grid-connected PV inverters. To facilitate low-voltage ride-through (LVRT), it is imperative to ensure that inverter currents are sinusoidal and remain within permissible limits throughout the inverter operation.