Adaptive Rate Reaching Law Based Sliding Mode Control for a Three-Phase F-type Converter Operated as Bidirectional Battery Charger and SAPF

This paper presents an adaptive rate reaching law based sliding mode control method for a three-phase F-type converter. Unlike the existing reaching laws in which the gain is always constant, the proposed reaching law employs an adaptive gain that is continuously updated with the grid current errors. This means that the gain can reach to its smallest value when the grid current errors are zero. It is shown that the minimum gain reduces the reaching time. As a consequence of using adaptive gain, the dynamic response of system is improved considerably (i.e: the reaching time is reduced). Moreover, it is shown that the three-phase F-type converter can be operated as bidirectional battery charger as well as shunt active power filter (SAPF) for compensating the nonlinear loads connected at the point of common coupling. The proposed control and correct operation of system are validated by MATLAB/Simulink simulations under various operating conditions which include battery charging mode, battery discharging mode, and simultaneous operation as SAPF and battery charging/discharging.