The Research On Direct Torque Control Applied To Mine Hoist Synchronous Motor

The mine hoist is the key equipment during producing of the coal mine. And its electric driving and control devices are always a research focus in many countries' electric driving. The present situation of hoist's power driving is analysed. Comparing with these, synchronous motor AC-DC-AC direct torque control system is the most preponderant scheme because it has high power factor and little pollution to the power network. Embarking from the actual need, the direction of electric driving and taking synchronous motor direct torque control system as research task, this has great realistic significance and wide applying foreground. But todays there is little research about it. Rectifer part and inverter part contruct the paper. PWM rectifier and synchronous motor direct torque are applied to the inverter part.PWM rectifier's keystone are discussed detailedly firstly. And model under d-q axis is constructed based on normal mathematic model. Combined with the specific demands of hoist, PWM rectifier's control strategy is researched. And vector control strategy based on decoupling control is put forward and applied to adjustable speed system. By using Matlab, the performance of rectifier's is researched systemically including system stable, dynamic state and state of rectification to inversion.And based on TMS320LF2407 DSP, the system's hardware and software are designed. Moreover, the system experiment is made in the laboratory to test the prior research results.The salient pole synchronous motor's mathematical model is studied under the differrent coordinate system.And the model of synchronous motor based on the Xad per-unit system is constructed. Direct torque control's principle,influencing factor of synchronous motor and simulation contrast research are studied separately.Exciting current control plan under unity power factor is given .And the system's performance of start without load and the load sudden change are researched.A hoist cycle is simulated combined with the specific demands of hoist. The simulation results prove that the request of hoist may be satisfied completely because performance of this plan is outstanding.