Direct Torque Control Method For Permanent Magnet Synchronous Motor With Contra-rotating Rotors

Ocean is one important thing for strategic significance in our country,All kinds of ships and underwater vehicle is indispensable tool for Marine development and future ap plication in the militar y field,And ship propulsion system and an important part of underwater vehicle,So the development of simple and compact structure,low noise,wide smooth speed reg ulation,safety and reliability and maintainability good propulsion system is one of the most important aspects of the development of Marine resources.In this paper,we study a Direct torque control system for a new kind of Dual-rotor permanent magnet machine with simple structure,high efficienc y and good controllability.First of all,the article expounds basic theor y of the new Dual-rotor permanent magnet machine,including the basic structure of the motor stator,operation principle,and discusses the b asic characteristics of the new Dual-rotor permanent magnet machine.The electromagnetic relations of Dual-rotor permanent magnet machine is anal yzed,including the equivalent magnetic circuit model of the motor and the circuit model,and analyse the energ y flow based on the analysis of the relationship.At the same time,to design a control strategy,we anal yz ed the motor vector diagram,and the mathematical modeling for motor,analyzes the current and voltage and equations of motion.Second,as a result o f this paper studies Dual-rotor permanent magnet machine have only one set of stator winding,we need the control strategy can control the bilateral rotor to achieve prevent the machine out-of-step When the motor is running under unbalanced load.So this method is proposed when a single inverter can not used to control the torques on both sides simultaneously,the control is applied only to the side with more significant torque ripples,with the control time determined by the positions of two rotors and the relationship between the electromagnetic torque and torque angle.And according to the established mathematical model,set the simulation model of the motor and control system in the MATLAB/simulink,verified the correctness of the direct torque control m ethod put forward in this paper.Third,design the direct torque control system test platform for Dual-rotor permanent magnet machine,and TI company DSP TMS320LF28335 as the core,including experimental prototype loading platform,AC-DC-AC main circui t design,the controller hardware design,software control algorithm implementation,etc.Finally,test control a permanent magnet synchronous motor with contra-rotating which rated speed of 500 r/min and rated power of 1.2 kW,and bilateral and unbalanced load of counter rotating motor respectively,anal yzing the test data,including counter rotating motor speed waveform,torque waveform,current voltage waveform,etc.B y loading test results show that the control system design is reasonable,and the motor running stable and reliable.