A New Shunt Active Power Filter Based on Indirect Matrix Converter Abstract: This paper proposes a new topology for active power filter (APF). In the proposed topology, the employment of an indirect matrix converter (IMC) as a part of shunt active filter has been investigated. Using the proposed IMC based APF, the dc link capacitor can be removed and also the average of dc link voltage can decrease in 1.5 times of the peak of source voltage. Furthermore, in this paper a new control method based on instantaneous power theory or P-Q theory and predictive current control for proposed APF is presented. In the proposed control method, there is no need to control the voltage of dc link and the average of voltage is always constant. Using PWM based control strategy, the injected harmonics will be produced around and more than switching frequency and the size of filters will be decreased. The simulation results obtained from PSCAD/EMTDC software confirm the validation of the proposed topology advantages and its control method. Keywords: Shunt active power filter, indirect matrix converter, dc link capacitor elimination, pulse width modulation. 1. Introduction Harmonic currents generated by power electronics- related appliances in industry are drawing more and more attention. Harmonics can not only influence the normal work state of electric equipments, but also interfere communication equipments [1]. To improve the power quality, some methods for harmonic suppression have been used in power systems. A solution of this problem is given by active filters which improve the energy quality of the electric suppliers, also because they can positively influence the symmetry and the values of power factor [2]. The conventional active filters frequently use dc link in their topology which can result in elimination of sudden variation of dc link voltage and consequently smooth injected current of active filter. But, it can cause the following problems: • Low reliability of protection system because of capacitive impedance of active filter, • difficulty in voltage stability, • high value of dc link voltage which will increase the rating of switches, • Increase of APF cost and size, according to use of high voltage capacitor. In accordance with the mentioned problems of using dc link capacitors, in order to eliminate these disadvantages some other alternatives can be used. One of these alternatives which can remove or decrease such problems is IMC based APF. The conventional matrix converter (CMC) is a direct conversion topology based on bi-directional controlled power valves. It is an alternative that replaces the rectifier, inverter and the storage energy stages of the typical variable speed drive, with only one stage and thus is an attractive option, when size and the need to remove big energy storage stage elements such as the dc-link capacitor are significant factors. The major drawback of this technology is the increased control complexity [3]. The (IMC) offers the same performance as the CMC [4], such as four quadrant operation, unity power factor, good voltage transfer ratio capacity and sinusoidal waveforms at variable amplitude and frequency during motoring and regeneration, but the control of the IMC is simplified in comparison with the CMC approach [5]. In this paper a new topology of Active filter based on IMC is introduced and then a new control method in accordance with P-Q theory and predictive current control will be applied to proposed APF. Finally, the simulation results will be demonstrated to verify the validation of the proposed topology and its control method. 2. Proposed Topology A conventional shunt APF is shown in Fig. 1 which contains a dc link capacitor and feed a nonlinear load incorporate with a power source. Here the APF is used as a higher order harmonics filter and eliminated load harmonics. Proposed topology of shunt APF is shown in Fig. 2. A balanced three phase source feeds a nonlinear load and an IMC. Indirect matrix converter is connected to line through a coupling transformer in parallel with load. In Fig. 2 load can be a rectifier with adjustable commutation angle. As shown in Fig. 2, IMCs contain a group of power semiconductors which is so closed to ac/dc/ac converters. Mentioned converter is divided to Ali Aghabeigi Heris, Ebrahim Babaei, Seyed Hossein Hosseini Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran E-mails: ali.aghabeigi88@ms.tabrizu.ac.ir, e-babaei@tabrizu.ac.ir, 581 ﻣﺘﻠﺐ ﺳﺎﯾﺖ MatlabSite.com MatlabSite.com ﻣﺘﻠﺐ ﺳﺎﯾﺖ