Research On Speed Sensorless Induction Motor High-performance Control At Low Speed

The electric drive system of speed sensorless high performance frequency conversion control system occupies an important position by virtue of low cost,good adaptability and high reliability.But the modern electric drive system requires short field debugging time,simple algorithm and large speed range.And try not to use the encoders,which are expensive,highly influenced by environmental temperature and humidity,and easy to be damaged.But at present,this technology still has many problems.It is unstable when the motor runs at low speed.For example,the state of power generation is unstable,the memory of high performance control technology is large and the debugging time is long.In this thesis,two commonly used high performance frequency conversion control methods are analyzed:vector control algorithm and predictive control algorithm.The correlation between them is analyzed and proved theoretically,and a control algorithm combining two methods is proposed,which reduced the complexity of the algorithm a certain extent.In view of the instability of rotating speed at low speed power generation,small signal analysis is carried out for the speed adaptive full order flux observer,the transfer function between the speed and the current is derived,the reason for instability is analyzed by Routh criterion,and the error feedback matrix which can achieve a full range of stability is analyzed.Based on Lyapunov stability theory and Popov's super stability theory,the speed adaptive law is obtained and improved.Mathematica mathematical and MATLAB/Simulink simulation software are used for theoretical analysis and simulation verification.It is verified that the speed reduction is sensitive to the parameters of the motor.And the speed estimation accuracy at low speed can be improved.In this thesis,an experimental system is set up,using the TMS320F2812 chip as the main control chip,asynchronous motor as driving motor,and DC motor as a load motor.By experimental means,the effect of observer improvement on low speed operation of motor and the effectiveness of the proposed control algorithm are verified.