A. Rahab.et.al. Int. Journal of Engineering Research and Application www.ijera.com ISSN : 2248-9622, Vol. 8, Issue 1, (Part -1) January 2018, pp.10-18 www.ijera.com DOI: 10.9790/9622-0801011018 10 | Page Direct Power Control of Three Phase PWM Rectifier based DSOGI-VF Estimator for No-Ideal LineVoltages Conditions A. Rahab *, F.Senani **, H. Benalla*** * Laboratoire de l’Electrotechnique de Constantine (LEC), Faculté des Sciences de la Technologie, Université des frères Mentouri de Constantine 1, Ain el-bey 25000 Constantine, Algerie ** Laboratoire de l’Electrotechnique de Constantine (LEC), Faculté des Sciences de la Technologie, Université des frères Mentouri de Constantine 1, Ain el-bey 25000 Constantine, Algerie *** Laboratoire de l’Electrotechnique de Constantine (LEC), Faculté des Sciences de la Technologie, Université des frères Mentouri de Constantine 1, Ain el-bey 25000 Constantine, Algerie ABSTRACT In this paper, direct power control (DPC) of three-phase pulse width-modulated rectifiers without line voltage sensors is presented. The new system is based on virtual flux (VF) using dual Second Order Generalized Integrator frequency located loop DSOGI-FLL estimator. In order to improve the VF-DPC performance of PWM rectifier, an improved observation method of virtual flux-linkage is proposed. To avoid the relevant problems of pure integrator, and to achieve the accurate observation of the grid voltage’s phase, (SOGI -FLL) are used to displace the pure integrator. Theoretical principles of this method are discussed. This strategy is also investigated under unbalance and pre-distortion grid. A theoretical analysis of active and reactive power under a non-ideal source is clearly demonstrated. In order to calculate the compensated powers, the extraction of positive, negative, and harmonic sequences of voltage and current is needed and a multiple DSOGI-FLL method is used for rapid and accurate extraction. It is shown that the VFDPC exhibits several advantages, particularly providing sinusoidal line current when the supply voltage is not ideal. Keywords - Three-Phase Rectifier, DPC, Virtual Flux Estimation, DSOGI-FLL, no-ideal grid voltage --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 14-12-2017 Date of acceptance: 03-01-2018 --------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION PWM AC/DC converters have several advantages such as low harmonic distortion of input currents, bi-directional power flow, high power factor and stable dc-link voltage [1]. Recently, due to the sharp increase of renewable energy sources connected to the grid, more and more converters are applied in wind turbines, photovoltaic system, fuel cells, energy storage system and flexible AC transmission system (FACTS) devices. At the same time, high power application in these renewable energy systems requires converters to operate more effectively in improving power quality and the transient stability [2].Therefore, advanced control techniques are very necessary to fulfill these standards. The three-phase pulse width-modulated rectifierscontrol approaches can be classified, as cited in the literature as a vector oriented control (VOC) and direct power control (DPC) [3],the vector control (VC) can be either based on grid voltage [4, 5, 6] or virtual flux (VF)[7] using proportional integral (PI) controllers. However, it has some disadvantages, such as its dependence on the system parameters variation, that its performance largely depends on the tuning of the PI parameters [8].In order to overcome complication due to the current control loops, an effective control, namely direct power control (DPC) has been developed [9],Direct power control (DPC) strategy has become one of the hot research topics in recent Years, because of its fast dynamic response, simple structure, and high power factor, and so on [10, 11].In general, the control of three-phase convertercontains more sensors (DC voltage sensor, power grid voltage sensors and AC current sensors) , which not only increases the volume of the system device, improves the system cost, but also reduces the system reliability [11]. The three-phase rectifier can be seen as a virtual AC motor, its virtual flux-linkage can be used to estimate the voltage of rectifier , But in the conventional virtual flux estimation ofthree-phase rectifier, there exists a pure integral link, and then the estimation process of virtual flux is inevitably affected by the initial value and the cumulative deviation of the integrator [11, 12 and 13,14, 15, 16, 17].the resolution of the problems of pure integration, more researchers focus on replacing the RESEARCH ARTICLE OPEN ACCESS