【正文】 the first pulse control and SI and S, during the second one. The above guarantee that switch mutation and conduction looses are equilibrated. . State machine representation for voltagesags. Fig. 5 shows the operation sequence of singlephase ACAC converter: Operation sequence of the ACAC converter. A Field Programmable Gate Arrays (FPGA) is used to program the state machine and to generate a dead time between the turn on and the turn off for the bidirectional switches. The FPGA permits to reduce the processing time of the DSP. In this case, The DSP only generates the voltage reference and the switching pattem. 1v. REFERENCE GENERATION The singlephase dq theory is used to realize the pensation process and to select the duty cycle. The dq theory transforms fundamental frequency signals into DC ponents, allowing a fast transient response to pensate voltage sags and swells. To achieve the singlephase dg transformation, an imaginary orthogonal system concept is introduced. The main idea is that the imaginary orthogonal variable keeps exactly the same system ponents and parameters, keeping always 90 phase shift with respect to real ponents [9]. In this paper, it is employed the proposal in [lo] which is based on the concept that the imaginary orthogonal circuit has a 90 lag. Fig. 6 shows the real and orthogonal imaginary variable used to determine the dq transformation from the AC mains. I Real and imaginary variables. 1613 The matrix transformation from real and imaginary circuit to the dq rotating frame is expressed by: 5:l (9) % I % where: Vd = Voltage of the real circuit. Vq = Voltage of the imaginary. A. 1 The dq transformation provides information about the active ponent to pensate. As an example, the Yd and V, ponents for a sinusoidal signal Ygin(wt) (without harmonic content) are P39。The 30th Annual Conference of the IEEE industrial Electronics Society, November 2 6,2020, Busan, Korea Compensation of Voltage Sags and Swells using a Singlephase ACAC Converter JOrge PhZ, Student member, IEEE, Victor Ciirdenas, Member, IEEE, Homero Miranda, Student member, lEEE and Ricardo AIvNeZ, Member,lEEE Centro de Investigacibn y Estudios de Posgrado, Facultad de Ingenieria, Universidad Autonoma de San Luis Potosi. Manuel Nava 8, Zona Universitaria 78290, San Luis Potosi, . MEXICO. Phone /Fax: 52(444) 8173381 : , , , . AbstractIn this paper, a topology to pensate voltage sags and swells simultaneously in critical loads is proposed. It consists in a singlephase ACAC converter in a matrix arrangement, which keeps a continuous regulation in the output voltage. The proposed scheme has the capability to pensate up to 25% voltage sags and 50% voltage swells. Energy storage devices are not required by the ACAC converter 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 pensation voltage. A four step switching technique is used to drive the ACAC converter switches, executing snubberless operation. The reference signal is generated using singlephase dq theory, obtaining a fast response time and bigh regulation. Simulation and experimental results of a 5kW capacity, 127V, 60Hz equipment are presented. I. INTRODUC~ON The quality of the AC mains has been affected by the use of new semiconductordevices technologies. Nowadays, it is mon to find disturbances in the amplitude or waveform shape of current and voltage in the electric systems. These conditions could produce fails in the equipments, raising the possibility of an energy interruption. The voltage fast variations that appear in the AC mains during 10 seconds or less are monly known as voltage sags and swells. These variations are produced by normal operation of high power loads as well as theirs connection and disconnection。 never should be closed at the same time in order to avoid a shortcircuit in the AC mains side. The switches are driven using a signal pattern which incorporate a fourstep switching strategy, reducing the switching losses and eliminating the use of snubbers circuits. 111. MODULATION