ENHANCEMENT OF FAULT RIDE THROUGH CAPACITY OF GRID CONNECTED INVERTER
Date
2023-04
Journal Title
Journal ISSN
Volume Title
Publisher
I.O.E. Pulchowk Campus
Abstract
Under the demands of contemporary grid code (GC), the solar PV system should stay
attached to the grid for a certain time period depending on the voltage sag level under the
fault condition. The voltage of the point of common coupling (PCC) is the same when the
fault appears on the grid side due to compensation of voltage by the grid connected system.
But the output voltage of inverter is very low when fault occurs in the inverter side
resulting in a very high DC connection voltage and very high current through the inverter
for the power balance. This high voltage of the intermediate circuit can damage the DC
link capacitor and high current during the transient fault may damage the inverter.
Moreover, the deflection of the voltage will cause the PV plant to be disconnected from the
network based on the modern GCs. But, due to on-growing demand of consumers, it is
required to connect the PV system to grid even during faulty condition.
This study proposes a DC Braking chopper approach for the two-stage grid-integrated
solar PV system to enhance fault ride through (FRT) capability. The proposed DC Braking
control approach consists of a resistor in series with IGBT which absorbs the excess
energy in the DC link capacitor during the fault, which will regulate the DC-link
overvoltage where required PWM signal for IGBT used in DC braking chopper is
generated by the principle of power balance between DC side and AC side.
Description
This study proposes a DC Braking chopper approach for the two-stage grid-integrated
solar PV system to enhance fault ride through (FRT) capability. The proposed DC Braking
control approach consists of a resistor in series with IGBT which absorbs the excess
energy in the DC link capacitor during the fault, which will regulate the DC-link
overvoltage where required PWM signal for IGBT used in DC braking chopper is
generated by the principle of power balance between DC side and AC side.
Keywords
Point of Common Coupling (PCC),, Grid Code (GC),, FAULT RIDE