Research Of PMSM Direct Torque Control In Electrical Propulsion Ship

Electric propulsion is one kind of propulsion who gets its propulsive power on its own power generation equipment, In the electric ship propulsion system, the AC power electric propulsion has already been the first option to be considered in the propulsion of ship, and so far, there appears the coexistence of many manners of push, such as induction motor, AC synchronous motor and permanent magnet synchronous motor, in these motors the PMSM has win people of all ages since its advantages, and its application in the electric propulsion ship has became more and more wider.With the continuous improvement of the AC motor control technology, many items of AC motor performance can be matched with DC motor. Following the VC system of AC motor, the Direct Torque Control (DTC) is another high-performance speed control system of AC motor. It focus on the direct control of the torque of motor, owning excellent static and dynamic speed performance because of its own advantage, people have given it more and more study as well as research.In this thesis, we choose PMSM as the study object. Firstly we introduce the present situation and development of DTC, then use the Matlab/Simulink software to build the model of the DTC system of PMSM, and complete the simulation of PMSM direct torque control system based on the analysis of the mathematical model of PMSM, the result of simulation shows that the stator flux trajectory of PMSM approached a circle, the speed, torque response of PMSM can both follow the given value quickly as well as timely, and the static, dynamic performance of DTC system can meet very high requirement; in the process of building the model of DTC of PMSM in this paper,we don't use the traditional method to build the model of DTC of PMSM in rotating coordinate system,we choose to realize the DTC system in the two-phase stationary coordinate system.This method is simple and clear,and easy to implement,the simulation result also shows that the PMSM DTC system has the same excellent performance;as to the closed-loop control of PMSM's torque,this paper has adopted zero-voltage vector,and the application of zero-voltage vector improves the problem of the pulsation of torque in DTC systemAt last, the thesis set up the hardware of PMSM DTC system according to the results of simulation, it includes the three-phase rectifier circuit, the inverter circuit, the detection circuit of three-phase stator voltage, current and the drive isolation circuit of power electronics, then based on Digital Signal Processor(DSP),the thesis conducts the direct torque control on one motor with the rated power of 2.2Kw.