###### Abstract  
This paper outlines some modifications to conventional active power filters (APFs) to compensate for the non-linearity of the load current. Since the APFs inject the required non-linearity of the load harmonic current to make the current source sinusoidal, a combination of passive power filters (PPFs) and APFs in series connection are more effective rather than individual usages. The proposed control approach based on sliding mode control (SMC) with a suitable sliding surface selection being applied to the proposed hybrid APF to increase the flexibility and reduce the complexity of the controller. An outstanding tracking process based on the reference current in the rotating _dq_ frame is tested and guarantees the rapid convergence exponentially. An extra control loop is provided for DC link voltage regulation to minimize the DC ripples and control the APF three-phase output voltage levels. The presented solution provides an effective and straightforward load voltage support, maintaining an excellent dynamic performance in load changing and current compensation. The experimental results represent the authenticity of the proposed hybrid APF performance through several different tests, implying a feasible control approach for active filtering systems. active power filter; control; harmonic compensation 202020  
has the function of compensating the grid voltage. In this case, using an integrated quality controller, even with harmonics in the load current and voltage, can assure that there is a regulated voltage with a low harmonic value [2; 3; 4]. Actually, the APFs as harmonic compensators based on a power electronics interface have been the focus of many researchers and industries due to their simple structure and non-complexity. Power electronics converters as the main part of these devices have been reviewed in prestigious literatures from different points of view [5; 6]. In the general classification, the converters used include voltage source inverters (VSIs) and current source inverters (CSIs). VSIs have been introduced in multi-level and multi-phase types, while in recent years, multi-level CSIs have been designed and implemented for harmonic compensation [7]. Likewise, CSIs have undergone their laboratory and industrial evolution and performance reporting and are presented in valid different structures [8]. These converter losses can be classified into four subdivisions, including passive output filter losses (AC losses), conduction losses, switching losses of power switches, and DC-side losses. Semiconductor conductive losses due to equivalent resistance and voltage drop in the conducting state and switching losses are due to the improper operation of the switches [9; 10]. In recent years, there have been many researches conducted on APF performance evaluation for load compensating. For example, the authors in [11] present the idea of using two VSI and CSI simultaneously. Since the load current and therefore the reference current comprises different harmonic components, it can play a significant role in dividing the reference current between the two converters with different separating. The differential behavior of DC capacitors and DC inductors in high-frequency and low-frequency currents is important for how the reference current is split between the CSI and the VSI. Based on the obtained mathematical equations, if the proposed low-frequency components are applied to the CSI and the high-frequency components are applied to the VSI, the proposed APF can meet the design objectives. A classic APF contains a VSI with a three-leg bridge structure and a DC link capacitor, whose topologies require a matching transformer and a large number of active switching devices, which causes many disadvantages, especially in losses. These considerations result in heavy weight and an expensive system [12]. The conceptual design of the components of this integrated active filter is presented in [13].