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ABSTRACT: This paper presents the analysis and design of a passivity-based controller (PBC) that can be used by a single-phase AC-AC converter to voltage sags and swells compensation. The parameters of the non-linear controller are chosen taking account the operation features of the converter. The response velocity as well as a fast stabilization time and implementation are considered. A model of the system is presented in order to know the behavior of the single-phase AC-AC converter and to validate the proposed control law. It can be noted that the use of the PBC in the system permits to keep a high and continuous regulation in its output voltage and it has the capability to compensate up to 25% voltage sags and 50% voltage swells. In this case, a DSP and a FPGA are used to program the passivity-based controller and to determine the state of the switches respectively. The performance of a 5 kVA-127 V, 60 Hz, single-phase AC-AC converter with the selected controller is presented by means of simulation and experimental results, which verify the viability of the proposed approach
International Power Electronics Congress, 10th IEEE; 11/2006
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ABSTRACT: In this paper, a topology to compensate voltage sags and swells simultaneously in critical loads is proposed. It consists in a single-phase AC-AC converter in a matrix arrangement, which keeps a continuous regulation in the output voltage. The proposed scheme has the capability to compensate up to 25% voltage sags and 50% voltage swells. The AC-AC converter does not require energy storage devices and it is connected between the AC mains and the load by using a series transformer. One of the advantages of this topology is that taps for the coupling transformer are no necessary to change the polarity of the compensation voltage. A four step switching technique is used to drive the AC-AC converter switches, executing snubberless operation. The reference signal is generated using single-phase d-q theory, obtaining a fast response time and high regulation. Simulation and experimental results of a 5 kW capacity, 127 V, 60 Hz equipment are presented.
Industrial Electronics Society, 2004. IECON 2004. 30th Annual Conference of IEEE; 12/2004
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ABSTRACT: In this paper, an analysis and selection of the optimal operation sequence that can be achieved with the four step switching technique is presented. The sequence is chosen in base to the operation features of a single-phase AC-AC converter used to compensate voltage sags and swells. The energy dissipation of the AC-AC converter switches as well as an easy implementation and reliability are considered. The reliability of the converter is increased due to the advantages that present the optimal sequence. The switch commutation and conduction looses arc equilibrated, guaranteeing that the energy dissipated by each switching device will be the same. The performance of the AC-AC converter with the selected sequence is presented by means of simulation and experimental results.
Power Electronics Congress, 2004. CIEP 2004. 9th IEEE International; 11/2004
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ABSTRACT: In this paper a comparison between hybrid modulation and space vector technique, applied to trinary hybrid multilevel inverter is presented. The objective of this comparison is to apply and to evaluate the vector technique to current active filters. In the hybrid asymmetric topologies, voltages in DC sources are not equal, and they are multiples one or other, achieving that the number of voltage levels will be increased. The space vector techniques have features such as low switching frequency and generation waveform with a low harmonic content in the PWM pattern. Furthermore, the voltages in common mode can be reduced. The space vector modulation technique together with the trinary hybrid multilevel inverter present several advantages and a good performance in this application.
Power Electronics Congress, 2004. CIEP 2004. 9th IEEE International; 11/2004
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ABSTRACT: In this paper, a current active power filter using a hybrid asymmetric multilevel inverter is presented and analyzed. The control proposed is based on a vector-control technique, generating an optimized switching pattern. The hybrid multilevel inverter increases the voltage levels number, reducing the harmonics associated to the commutation frequency. The hybrid multilevel inverter is structured by two cascaded-inverters, and the DC link voltage between the stages has the relation 1:3, generating 9 voltage levels. The signal reference is generated using a variant of the single-phase d-q Theory, allowing a fast transient response and stability. Simulated waveforms prove the viability of the control scheme and the multilevel active current filter proposed.
Power Electronics Specialists Conference, 2004. PESC 04. 2004 IEEE 35th Annual; 07/2004
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ABSTRACT: This paper presents a series active filter with a low-order and simple controller, used to cancel the voltage harmonics in single-phase systems. To accomplish this objective, the series active filter is forced to inject the appropriate voltage to the line through a series connected transformer. The active filter is capable to reduce the total harmonic distortion of the AC mains from 11% to 4%, and it presents a fast response velocity. Analysis and modeling are presented as well as simulation and experimental results, which verify the viability of the proposed approach.
Power Electronics Congress, 2002. Technical Proceedings. CIEP 2002. VIII IEEE International; 11/2002
