Abstract
The paper includes the comparative analysis of efficiency of different pulse width modulation (PWM) algorithms implemented in active rectifiers (AR) of high-power three-level frequency converters (FC) of main rolling mills electric drives in terms of providing stability during external voltage drops. Modern electric drives of rolling mills are usually developed on the basis of powerful synchronous motors and frequency converters consisting of active rectifiers and inverters. Unbalanced voltage drops that occur in the external power supply often lead to breakdowns of the main electric drives, which leads to economic losses: defective products and downtime. Ensuring stable operation of rolling mills in such modes is an important task. The objects of study are continuous cold rolling mill 2000 of the PJSC "MMK" and hot rolling mill 1750 of the CJSC "MMK Metalurji". Mathematical models of frequency converters have been developed using by the Matlab-Simulink software for the following PWM algorithms: classical, vector, selective harmonic elimination and fixed pulse pattern control. The mathematical models have been used to study the operation of the active rectifier for normal operation mode and for single-phase voltage drops with a depth of 30% and a duration of 200 ms. Also on the basis of the mathematical model, the analysis of active rectifier input currents and DC-link voltage has been made. Studies have shown that AR faults can occur by operation of input overcurrent protection or DC-link minimum voltage protection. The comparative analysis results of working of FC-AR with different PWM algorithms for voltage drops conditions based has been presented. Also the conclusions about the influence of regulators parameters in AR control system on stability of working of FC-ARs for voltage drops situations have been made.
Keywords
Active rectifier, frequency converter, pulse-width modulation algorithms, mathematical model, voltage drops, electric drive stability, control system, rolling mill.
1. Nikolaev A.A., Kornilov G.P., Ivekeev V.S., Lozhkin I.A., Kotyishev V.E. Using of the Static Var Compensator of the Ultra-High Power Electric Arc Furnace for Supporting of Electrical Power System Stability and Increasing Reliability of Factory Power Supply. Mashinostroenie setevoj ehlektronnyj nauchnyj zhurnal [Russian Internet Journal of Industrial Engineering], 2014, no.1, pp. 1-11. (In Russian)
2. GOST 32144-2013. Electric energy. Electromagnetic compatibility of technical equipment. Power quality limits in the public power supply systems. Moscow, Standartinforn Publ., 2014. 20 p. (In Russian)
3. Nikolaev A.A. Povyshenie effectivnosti electrotechnicheskogo complexa “dugovaya staleplavilnaya pech – staticheskii tiristornii compensator” [Improving the Efficiency of Electrotechnical Complex of Electric Arc Furnace and the Static Var Compensator] Magnitogorsk, MSTU Publ., 2017.
4. Khramshin T.R., Kornilov G.P., Nikolaev A.A., Khramshin R.R., Krubtsov D.S. Research of Influence of High Power Active Rectifiers on Mains Supply. Vestnik IGJeU [Journal of ISPU], 2013, no.1, pp. 80-83. (In Russian)
5. Maklakov A.S. Simulation of the Main Electric Drive of the Mill Rolling Stand. Mashinostroenie setevoj ehlektronnyj nauchnyj zhurnal [Russian Internet Journal of Industrial Engineering], 2014, vol.2, no.3, pp. 16-25. (In Russian)
6. Hramshin T.R., Krubtsov D.S., Kornilov G.P. Mathematical model of the active rectifier under unbalanced voltage operation conditions. Elektrotekhnika setevoj ehlektronnyj nauchnyj zhurnal [Russian Internet Journal of Electrical Engineering], 2014, vol. 1, no. 2, pp. 3-9. (In Russian)
7. Krubtsov D.S., Hramshin T.R., Kornilov G.P. Active rectifiers control methods of main drive of rolling mills. Aktualnye problemy sovremennoj nauki, tekhniki i obrazovaniya [Actual problems of modern science, technology and education], 2013, no. 71, pp. 3-6. (In Russian)
8. Hramshin T.R., Krubtsov D.S., Kornilov G.P. Evaluation of methods PWM voltage active rectifiers rolling mills. Mashinostroenie setevoj ehlektronnyj nauchnyj zhurnal [Russian Internet Journal of Industrial Engineering], 2013, no.2, pp. 48-52. (In Russian)
9. Gasiyarov V.R., Radionov A.A., Maklakov A.S. Simulation of 3L NPC Converter with selective harmonic elimination PWM. Elektrotekhnicheskie sistemy i kompleksy [Electrotechnical Systems and Complexes], 2017, no. 1 (34), pp. 4-9. (In Russian)
10. Maklakov A.S., Maklakov E.A., Antonova E.V. Space Vector Modulation algorithm of three-level Converter. Aktualnye voprosy ehnergetiki: materialy Vserossijskoj nauchnoj konferencii studentov, magistrantov, aspirantov [Topical issues of energy: materials of the all-Russian scientific conference of students, masters, postgraduates]. Omsk, 2016, pp. 100-106. (In Russian)
11. Azeddine Draon, Senior Mieee A space vector modulation based three-level PWM Rectifier under Simple Sliding Mode Control Strateg. Energy and power Engineering, 2013, no. 5, pp. 28-35.
12. Farhan Beg Space Vector Pulse Width Modulation Technique Based Design and Simulation of a Three-Phase Voltage Source Converter System. World Academy of Science, Engineering and Technology, 2014, no. 9, pp. 1304-1307.