Based On The Back - To - Back Converter Pch Control Of Ac Motor Is Studied

AC drive system based on the back-to-back converter is widely used in motor speed control, electric energy conversion and power systems and other fields, which has advantages, such as flexible power control, small output harmonic content, bidirectional energy flow and so on. However, back-to-back systems are nonlinear and complex control systems with high-order, multiple variables, close coupling and time-varying parameters. The problems, such as independent control between the grid-side and the motor-side parameters’change in real time and uncertain load, can not be solved completely by the traditional control strategies, and affect comprehensive control and performance problems of the system. And dynamic and stable performance of the system needs to be improved.For some disadvantages in B2B system, the research of some nonlinear control methods has been intensified. In recent years, motor control methods based on the energy shaping and port-controlled Hamiltonian (PCH) has attracted some experts’ attention, and a series of research findings have been obtained. In this paper, speed controllers are designed based on the interconnection and damping assignment passivity-based control method, to achieve four-quadrant run of the whole system.First of all, the present situation and development tendency of Back-to-Back converter systems at home and abroad are shown, as well as the main circuit, control circuit, control strategies of the system.Secondly, some basic theories of Energy Shaping (ES) and PCH control principle are introduced. The PCH control method based on PCH model is given, including state PCH method and state error PCH method based on PCH model. And we analyze the advantages and disadvantages of various control methods.Thirdly, Back-to-Back converter system models are constructed in the stationary and rotating reference frame respectively. Then the PCH model of system is given in dq frame. And independent control strategies between two sides of the Back-to-Back converter system are studied. It mainly comprises vector control strategy, vector control and PCH control, state PCH control on both sides, state error PCH control on both sides. Speed controllers are designed when there are no disturbances and load torque exits disturbances. To improve the dynamic performance, we apply PI control.Then, the whole system model is realized, with Space Vector Pulse Width Modulation (SVPWM) methods. And simulation is studied in Matlab/Simulink. Simulation results show the control methods are effective. We also compare the PCH control method with other control methods.At last, the research works in this paper are summarized, the problems in the passed research are proposed and the future research works are also presented.