Research On Feedforward Field-weakening Control Of Permanent Magnet Synchronous Motor

With the development of the science and technology, the research and application of AC adjusting speed system have developed rapidly, and especially the high performance permanent magnet synchronous servo system. So its performance requirements are higher. It demands not only larger torque in low speed, but also wider speed range and stable operation. So the research of field-weakening control based on permanent magnet synchronous servo system is becoming a research hot spot.First of all, this paper introduces the domestic as well as foreign development present situation and the future trend of the development, and also deduces the coordinate transformation in vector control method, describes the mathematical model in different coordinate system, and then introduces the space vector PWM and several current control methods in vector control system.Besides, analyzes field-weakening control method, especially the feedforward field-weakening control method which includes the Maximum Torque per Ampere (MTPA) control method used below base speed and the feedforward field-weakening beyond base speed.What’s more, because the regulator is very important in control system, how to design the regulator parameters becomes important. This paper introduces the regulator design method of current loop and speed loop and gives the detailed calculation process.To make sure the correctness of the theory analysis, simulation based on Matlab is used including double closed loop control system simulation. MTPA control method simulation and feedforward field-weakening method simulation.At last, finishes the experiment based on DSP28335of TI Company, compares the results with the simulation results as well as the theoretical analysis results and further proves the correctness of control algorithm.