STABILITY CRITERION FOR CONTROL LOOP OF GRID-CONNECTED CONVERTER UNDER WEAK GRID CONDITION

The present disclosure provides a method for determining a stability criterion for a control loop of a grid-connected converter under a weak grid condition, and belongs to the field of power control. The method includes performing a sampling, obtaining an expression of a transfer function of each of control loops of a grid-connected converter, further obtaining an expression of a transfer function for indicating stability performance of the system, obtaining an amplitude expression and a phase expression according to the transfer function, and providing a stability criterion for the control loop of the grid-connected converter under a weak grid condition and a stability margin expression of the system. The stability criterion for the control loop is significant and provided by a simple method, can quickly and accurately determine the stability of the grid-connected converter system under the weak grid condition, and is helpful for the parameters design of the controllers.