A Current-Limiting Scheme for Voltage-Controlled Inverter Using Instantaneous Current to Generate Virtual Impedance

Abstract

In this paper, a current-limiting scheme is proposed for the voltage-controlled inverter. The method utilizes instantaneous current to quickly activate a resistive fault-current-limiting virtual impedance (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FCL</sub> ) to suppress the instantaneous impulse current and steady-state overload current, which can be directly integrated into the existing voltage-type control scheme. When a fault occurs, the inverter can be kept in the voltage control mode without mode switching. After the fault is cleared, it can automatically return to the normal operation mode. The parameter selection method of the current-limiting virtual impedance is analyzed, and the logic criterion for short-circuit fault clearance is presented to realize the automatic startup and exit of the current-limiting virtual impedance. Finally, the RT-LAB hardware in-loop experiment and the single-phase inverter platform experiment prove that the proposed current-limiting scheme can simplify the fault handling process and improve the anti-fault ability of the voltage-controlled inverter.