Research On Three-level Inverter Variable Frequency Drive System For Mine Hoist

Mine hoist is mainly responsible for working on the underground transportation, the speed controling performance of mine hoist is required better. Because three-phase squirrel cage asynchronous motor has simple structure and is easy to maintenance, it is widely used. Three-level neutral-point-clamped(NPC) inverter can receive better sine wave which is beneficial to motor operation, when it works in conjunction with SVPWM method, the system can achieve ideal control effect. Sliding Mode Variable Structure instead of PI structure is used in the system, the motor has advantages of fast response speed, strong robustness against the parameter variations and so on. In this thesis, completing the work that research on three-level inverter variable frequency drive system for mine hoist.Firstly, the structure of mine hoist drive system is introduced, the working principle of three-level NPC inverter is analyzed, and the theory of vector control is introduced in detail, which can reach a high performance for motor control. Then, SVPWM method is introduced and simulated in detail, the simulation results indicates that the control strategy is good for waveform modulation. SMVSC is used in the system that aims at the step of speed controller, SMVSC method is introduced, and sliding mode speed controller is designed, the drive system of sliding mode speed controller is simulate, compared with traditional PI speed controller, the result validates that sliding mode speed controller has advantages of fast response speed, overshoot, strong robustness and so on. Next, the hardware and software of variable frequency drive system for mine hoist which is based on DSP TMS320F2812 is designed. Finally, make a summary of the full thesis, the Sensorless Vector Control System based on Sliding Mode Control has good speed identification, fast response speed and strong robustness. It can be well applied to variable frequency drive system for mine hoist.