Six Phase Induction Motor Control System Design For The Ship Electric Propulsion

In recent years, ship electric propulsion system has been an unprecedented development,in which the propulsion motor is the main power of the ship electric propulsion system. So the research on the propulsion motor control system is one of the key technologies of propulsion ship power system. The six phase induction motor control system has features such as low voltage power device to realize high power, better redundancy and small torque ripple, therefore,which is suitable for the ship electric propulsion system, and research on the six phase induction motor control system has practical value and application prospect. The design of the six phase induction motor control system for the ship electric propulsion system is studied.Firstly, the winding structure of the six phase induction motor is introduced. The mathematical model of the six phase induction motor based on the nature is established, and the space decoupling transformations in six dimensional spaces is analyzed. After space decoupling transform, the mathematical model of the six phase induction motor under the cardinality of harmonic has been achieved,which provide a theoretical basis for the vector control scheme of the six phase induction motor.Secondly, the SVPWM technology of the six phase induction motor is researched. First of all, the traditional SVPWM which will produce larger stator harmonic current is analyzed. Then six phase SVPWM technology based on the intermediate vector is analyzed, which uses 64 kinds of basic space voltage vector to compose intermediate voltage vector, and intermediate voltage vector can satisfy the average volt second value of z1-z2 subspace,then the intermediate voltage vector is used to compose the reference voltage vector,so the reference voltage vector not only meet the requirements of the reference voltage vector of d-q subspace, but also make the average volt second value of z1-z2 subspace to remain zero,which can effectively reduce the harmonic current in the stator winding.Thirdly, the hardware circuit of the six phase induction motor based on TMS320F2812DSP controller is designed. First, the overall design scheme of the system is analyzed, and the controller is divided into two parts: the power circuit and the control circuit. The power circuit consists of two main components: rectifier and inverter. Three-phase uncontrolled rectifier is adopted as the rectifier part, and two IPM is adopted as inverter part. The control part includes TMS320F2812DSP, optocoupler isolation circuit, current detection circuit, speed detection circuit, DC-bus voltage detection circuit, over-voltage detection circuit, current limited circuit,IPM fault output isolation circuit,fault protection circuit,serial communication circuit,and the principles of every part are given in detail.Fourthly, the software design of the six phase induction motor vector control system is completed. The TI Company's CCS software is used as the system development environment,and the overall design scheme of the software part is analyzed. The per unit process of the six phase induction motor model and method for numerical processing in the program are given.The control system software includes the main program and interrupt service program, the main program initializes the hardware, the variable and each register. PWM interrupt service program includes ADC sampling module, speed detection module, SVPWM module and feedback module. Serial communication interrupt service program is designed to realize the direct data transmission with upper PC.Finally, the feasibility and correctness of the six phase induction motor controller are verified by experiment, and it has good application value.