Three-Phase Drive System Using Three Phase Rectifier For Driving Induction Motor MD.Parvez 1, P.Varunkrishna 2 1 M.Tech student, EEE, Arjun College of Tech &Science, R.R.Dist, Telangana, India 2 Assistant professor, EEE, Arjun College of Tech &Science, R.R.Dist, Telangana, India ABSTRACT: This paper présents a single phase to 3-phase drive system that consists of 2 parallel single phase rectifier, 3- phase inverter and also induction motor.the main objective of this schème is to reduce the switching currents of an rectifier, total harmonic distortion at the input side of the converter and provides fault tolerance to be better imrovised.we also observed from expiremental results that even when number of switches increases total energy loss is not going to be incresed further and even lower as compared to conventional system. Also important moto is to diminishing circulation current in the model with help of PWM technique and all results are verified with Matlab Simulink. When an isolation transformer is not employed in that case of the total reduction of present circulating currents distributed in converter stages is an main moto/aim in the overall system design. Single-phase to -phase ac dc ac conversion generally uses a full-bridge topology, that implies in ten power switches, as depicted in Fig. 1. I. INTRODUCTION Power electronic converters are becoming more popular in industrial, commercial and residential applications for reducing size and weight, as well as for increasing performance as well as functionality. It is often to have only a single phase power grid in residential, commercial, and manufacturing, especially in many of the rural areas, besides the adjustable speed drives may be request a three phase power grid need fully. Singlephase to 3-phase ac dc ac conversion generally employs a full-bridge topology, which results in many ten power switches. The converter below is denoted here as conventional topology. Recently Parallel converters have been extensively employed to improve the power capability, reliability, efficiency, as well as redundancy. Here in this scenario. Here we took the help of different Parallel converter techniques that improves the performance criteria of active power filters, uninterruptible power supplies (UPS), fault tolerance of existed doubly fed type induction generators, on the other way 3-phase drives. Usually the role of converters in case of parallel needs a transformer for isolation purpose. Moreover, weight, size, and cost associated with the transformer cause such a undesirable solution. Fig. 1. Conventional single-phase to 3-phase drive system. Fig. 2. Our Proposed single-phase to three-phase drive system. In this present paper, we proposed a single-phase to 3-phase drive system consists of basically 2 parallel single-phase rectifiers as well as three-phase inverter which is shown in Fig. 2. ISSN: 2348 8379 www.internationaljournalssrg.org Page 1
The proposed system is designed to operate at the single-phase utility grid which is a unique availabilty option. As compared to the conventional topology, the proposed system permits the following: To diminishes the rectifier switch currents Overall harmonic distortion (THD) of connected grid current with similar switching frequency and Finally to increase the fault tolerance characteristics. Moreover to this,overall losses of the proposed system may be much lower than that of the conventional system. The above mentioned benefits judges the starting investment input of used proposed system, due to the increase of count of switches. II. SYSTEM MODEL The proposed system consists of grid, input inductors (La, La, Lb, and Lb ), rectifiers (A and B), elcetrolytic capacitor bank at the dc link, inverter, and induction machine. Rectifiers A and B contains of switches qa1, qa1, qa2, and qa2, and q b1, qb1, qb2, and qb2, respectively. Likewise inverter is constituted of switches qs1, qs1, qs2, qs2, qs3, and qs3.the conduction state of the switches is represented by variable sqa1 to sqs3, and sq = 1 shows a closed switch while sq = 0 an open one. A. DC Link Capacitor A simple derived expression for the stress current on the DC-link capacitor that makes load-side inverter for a voltage DC-link-converter system is to be correctly derived. Now the DC-link capacitor RMS current value is found from the depth of modulation and also with the help of amplitude and the phase angle of the inverter current output while assumes a sinusoidal inverter current output and a constant DC-link voltage. At the other end ignore the ripple output-current, the results of the analyzed calculation are in vicinity of 8% of measurements are brought to be from digital simulation and an experimental system, even if the current output- ripple is gradually high for low-frequency inverter systems that employs IGBT. The simple analyzed expression provides main advantages over simulation methods for purely designing the DC-link capacitor of converter systems with PWM. III. FAULT COMPENSATION The proposed system presents over here redundancy of the rectifier converter, that can be useful in especially a fault-tolerant systems. We observer that proposed system can helps for compensation for open-circuit and short-circuit failures that occurs especially in the rectifier or inverter converter devices. As shown in Fig. 2, the equations can be derived for the front side-end rectifier.1.2.3 Where p=d/dt and symbols like r and l represent the resistances and inductances of the input inductors and. Fig. 3 Proposed configuration highlighting devices of fault-tolerant system It also seems to be fault compensation is greatly achieved by reconfiguring the power converter topology by taking help of isolating devices (fastactive fuses Fj, j=1,...,7) and connecting devices (backto-back connected SCRs t1, t2, t3), as observed in Fig. 3. ISSN: 2348 8379 www.internationaljournalssrg.org Page 2
Post-fault system fault at the rectifier B side Fig. 4 Block diagram of the fault diagnosis system. In this figure 4, block fault identification system (FIS) detects as well as finds exact location of the faulty switches, by defining the leg that is to be isolated from the unit. which is based on the analysis of the pole voltage error. The fault detection as well as identification is considered in below four steps: 1) Taking the measurement of pole voltages 2) Computation of the error voltage by comparison with the acquired reference voltages and previously affected measurements in previous Step1); 3) determination is to be done whether errors matches or not to be considerd to faulty condition; which can be implemented by the hysteresis detector. 4) identification of the faulty switches Post-fault system fault at the rectifier A side Post-fault system fault at the inverter side. Fig. 5 Possibilities of configurations in terms of fault occurrence. This way, four possibilities of configurations have been considered in terms of faults: 1) pre-fault ( healthy ) nature 2) post-fault operation with fault at the rectifier B side post-fault operation with fault at the rectifier A side 4) post-fault operation with fault at the inverter side IV. RECTIFIER AND INVERTER Prefault system. A. AC to DC converter A rectifier is used to convert alternating current into direct current and process of converting termed to be rectification.it uses in power supplies and detectors in case of radio eqipments.itis available in several strucures like solid state,vaccum etc. ISSN: 2348 8379 www.internationaljournalssrg.org Page 3
Fig. 6 A three phase bridge rectifier For three-phase AC, 6 diodes are used. Generally there are 3 pairs of diodes, each pair, even of same kind of double diode that might be used for a full wave singlephase rectifier. Besides other pairs are in series (anode to cathode). Typically, commercially available double diodes have four terminals so the user can configure them as singlephase split supply use, for half a bridge, or for three-phase use.most of the devices which generates alternating current (such devices are reffered alternators) generate 3-phase AC. Fig. 9 Experimental results for a volts/hertz transient applied to 3-phase motor. (a) Grid voltage and gird current Fig. 9 b) Capacitor voltage ( Fig. 7 Three phase input Fig. 8 Three phase full wave rectifier V. EXPERIMENTALRESULTS We have observed some of experimental results that were obtained for transient in the machine voltages, as observed in Fig. 6. A volts/hertz control was applied for the three-phase machine, from V/Hz=83.3 V/40 Hz to V/Hz=125 V/60 Hz Fig. 9. (c) Currents of rectifiers and ISSN: 2348 8379 www.internationaljournalssrg.org Page 4
As shown above transient applied to 3 phase motor we observed that grid current is increasing gradually as time increases but grid voltage remains constant. Fig. 11.Experimental results highlighting the interleaved operation (double carrier PWM). (a) Complete view. Conclusion Fig. 10. Experimental results of the proposed configuration when a fault is identified at the rectifier B. ((a) Currents of rectifiers ) and A single-phase to three-phase drive converter composed of two parallel single-phase rectifiers and a three-phase inverter was proposed successfully with practical results. Here the system combines in parallel two rectifiers without use of transformers, and it is optimized when the load frequency is equal to that of grid voltage. The system model and the control strategy, including the PWM technique, have been developed. The proposed topology permits to reduce the current and consequently to reduce the power ratings of the power switches of the rectifier. Finally a Matlab/Simulink based model is developed and simulation results are presented. REFERENCES [1] P. Enjeti and A. Rahman,.A new single phase to three phase converter with active input current shaping for low cost AC motor drives,. IEEE Trans. Ind. Appl., vol. 29, no. 2, pp. 806.813, July/Aug. 1993. Fig. 10. (b) Currents of rectifier A (( and ( ). [2] J. Itoh and K. Fujita,.Novel unity power factor circuits using zero-vector control for single phase input systems. IEEE Trans. Power Electron. vol. 15, no. 1, pp. 36.43, Jan. 2000. [3] R. Q. Machado, S. Buso, J. A. Pomilio, and F. P. Marafao,.Three-phase to single-phase direct ISSN: 2348 8379 www.internationaljournalssrg.org Page 5
connection rural cogeneration systems,. in roc.ieee APEC, 2005, pp. 1547.1553. [4] O. Ojo, W. Zhiqiao, G. Dong, and S. Asuri,.High-performance speedsensorless control of an induction motor drive using a minimalist single phase PWM converter,. IEEE Trans. Ind. Appl., vol. 41, no. 4, pp. 996. 1004, July/Aug. 2005. [5] P.-T. Cheng, C.-C. Hou and J.-S. Li, Design of an auxiliary converter for the diode rectifier and the analysis of the circulating current, IEEE Trans. Power Electron., vol. 23, no. 4, pp. 1658 1667, Jul. 2008. [6] H. Cai, R. Zhao, and H. Yang, Study on ideal operation status of parallel inverters, IEEE Trans. Power Electron. vol. 23, no. 6, pp. 2964 2969, Nov. 2008. &Sci, Author 3 R.R.Dist, Telangana, India. Muthyala Sudhakar Assistant professor(c) in EEE Dept., U.C.T O.U Hyderabad, Telangana,India. [7] J.R.Rodr ıguez, J. W. Dixon, J. R. Espinoza, J. Pontt, and P. Lezana, PWM regenerative rectifiers: State of the art, IEEE Trans. Ind. Electron.,vol. 52, no. 1, pp. 5 22, Feb. 2005. [8] M. N. Uddin, T. S. Radwan, and M. A. Rahman, Fuzzy-logiccontroller-based cost-effective fourswitch three-phase inverter-fed IPM BIO DATA Author 1 MD.Parvez currently pursuing his M.Tech, in Arjun college of Tech &Science, R.R.Dist, Telangana, India. Author 2 P.Varunkrishna (Asst.Prof. Arjun College of Tech ISSN: 2348 8379 www.internationaljournalssrg.org Page 6