Research On Frequency Conversion Control System Of Mine High Voltage PMSM

With the rapid development of social economy and science and technology,the consumption of energy is also getting faster and faster,especially the use of electric energy in the coal industry is getting larger and larger.In order to maximize the utilization and integration of coal resources in China's coal mining industry,many coal companies are gradually actively participating in transformation and reform.The vigorous development of new equipment and new technologies provides a strong boost for the development of the coal machine industry.The frequency conversion control system of the mining high-voltage permanent magnet synchronous motor plays an increasingly important role in the production and use of coal machine industry equipment.This article first discusses the domestic and foreign research status of variable frequency control of mining high-voltage permanent magnet synchronous motors,comparatively analyzes the topological structure of four main circuits of high-voltage inverters,and designs a system scheme of variablefrequency control of mining high-voltage permanent magnet synchronous motors.Introduce 3.3k V three-phase AC voltage from the high-voltage interface under the mine,adopt multiple phase-shifting transformers,obtain the secondary high voltage of AC 1850 V on the rectifier side,and adopt the midpoint clamp type three-level inverter circuit on the inverter side.The control strategy of PI limiting,flux linkage conversion and indirect torque feedback is adopted,and the established three-loop vector control system based on stator side current,magnetic flux and rotor side speed is used to control and adjust the speed of the permanent magnet synchronous motor.Using Simulink environment in Matlab,two sets of simulation experiments were carried out to verify the effectiveness and good robustness of the built control model.Then detailed harmonic analysis was carried out on the input side and output side of the rectifier module and the three-level inverter module,respectively.Based on the comparison of the two-level and three-level output current and voltage waveforms,the characteristics of their respective harmonic distributions are obtained,and the effectiveness of the removal of even harmonics is verified by the half-wave symmetry of the simulated waveforms.Finally,the practical application of high-frequency permanent magnet motor frequency conversion control on scraper conveyor under mine is studied.The principle of high-voltage permanent magnet variable-frequency dual-machine drive is analyzed,and the difference of the inherent mechanical characteristics of multiple motors is the most fundamental factor that causes the unbalanced power operation.The high-voltage permanent magnet frequency conversion dualmachine drive scheme is proposed.The control strategy of the motor uses realtime feedback of load torque and adjustment and distribution control strategy.It is verified that the system can effectively meet the load balancing requirements of power balance.