Super Twisting Algorithm Based Sliding Mode Control Method for Single-Phase Dynamic Voltage Restorers

This paper presents a super twisting algorithm (STA) based sliding mode control (SMC) method for single-phase dynamic voltage restorers (DVRs). The proposed control method eliminates chattering and achieves constant switching frequency. The STA is usually considered as high-order sliding mode (HOSM). The main advantage of HOSM is that its acts on the high-order derivatives of the sliding surface while preserving the inherent advantages of first-order sliding modes and reducing the chattering phenomenon while increasing the accuracy. Hence, the consequence of applying STA in DVR control is that a continuous control input is obtained which can be compared with the triangular carrier signal to produce the pulse width modulation (PWM) signals. The theoretical considerations and analytical results are verified through computer simulations. It is shown that the load voltage is maintained at desired level under voltage sags and voltage swells in the grid.