Summary With the advancement of power electronics and control techniques, the renewable energy sources are integrated to the grid through highly efficient power electronic interfaces. The voltage source inverter connected at the grid acts as shunt active power filter to mitigate the power quality issues in addition to the power conversion. In this paper, the double‐band hysteresis current controller is implemented to ensure the real and reactive power flow from renewable energy system (RES) to the grid through voltage source inverter. In order to show the efficacy of the controller, 3 different modes depending on the climatic conditions such as (1) no RES power, (2) lacking RES power, and (3) surplus RES power are taken into consideration. The synchronous detection method with equal current criterion is used to generate the reference current. This criterion makes the grid currents balanced and sinusoidal even under unbalanced grid voltage conditions. The control system guarantees the unity power factor in the grid side with reduced total harmonic distortion in the presence of nonlinear loads. The average switching frequency is also reduced using double‐band hysteresis current controller which is proved by simulation, and the performance of the system is validated with the experimental results.

Development of control technologies facilitates the integration of renewable energy sources to the grid through power electronic converters. In this study, the inverter acts as shunt active power filter along with the power conversion operation. Various sliding mode control (SMC) techniques namely relay and signum method, hysteresis method and equivalent control method are implemented to control the real, and reactive power flow between Renewable Energy System (RES), load and grid using an inverter. To reduce the complexity, the control law (u eq) for equivalent control method is derived using a simple singlephase equivalent circuit of a three-phase voltage source inverter. In this study, the robustness is enhanced by choosing the integral sliding surface. These controllers are used to reduce the total harmonic distortion (THD) and to ensure unity power factor (PF) in the grid during balanced and unbalanced grid voltage conditions even in the existence of nonlinear loads. The SMC using equivalent control function outperforms the other methods in terms of chattering, THD and PF. To illustrate the effectiveness, three different modes are considered: (i) no RES power, (ii) insufficient RES power and (iii) excess RES power. The performance of controllers is validated by the simulation and experimental results.

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