Research On Variable Speed Ac Drives Of Induction Motor Based On Current-Source Converter

Converter is playing an important role in industrial production as continuous improvement of the modern industrial electrification degree.Speed control system for induction motor can be divided into voltage source converter driven asynchronous motor speed control system and current source inverter driven asynchronous motor speed control system depending on the nature of the power supply.There are many advantages of current source driven asynchronous motor,such as dynamic response speed,easy to achieve regenerative braking and four-quadrant operation,which promotes the rapid development of current source asynchronous motor speed regulating system.The current source asynchronous motor speed control system is studied in this paper.Firstly,the research and application status of current converter and AC speed control system are introduced in this paper.And the development of the converter is analyzed.Then the topology,working principle and control strategy of current-mode converter are studied.The TPWM modulation method is analyzed in detail and a current source converter is designed which is use PWM modulation.A current source converter simulation model is established by using Matlab/Simulink.The simulation results verifies the correctness of the theory.Secondly,an asynchronous motor vector control system is designed which is driven by current source.The principle of vector control is analyzed in detail and the mathematic model of each control module is established in the vector control system.The simulation model of vector control system are built based on above mathematic model.The AC variable speed system for asynchronous motor which is driven by current source is designed in accordance with the working principle of the current source converter,PWM pulse module,vector control module and the motor module.The simulation results show that the stator current curves,the speed curves and the electromagnetic torque curves of the speed control system have achieved the expected effect in different operating modes,which verified the excellent speed regulation performance of current source converter driven AC variable speed systemThe hardware design and software design of current source converter driven asynchronous motor speed control system are completed in the paper.The hardware design of the system includes the main circuit,drive circuit,alarm circuit,signal sampling detection circuit and protection circuit.The software design of the system includes the main,control interrupt service program,fault interrupt protection program,control module program.Finally,the platform of AC variable speed system of induction motor are tested.The experimental results prove the correctness of the design and the good dynamic performance of the speed control system.