The Research Of The Motor Vector Control Scheme Without Speed Sensor

AC motors are in an advantaged place comparing with DC motors on account of the more simple structure,the lower expense as well as the adaptation for several extreme environmental conditions.However,because they are much more complicated in speed regulation than DC motors,which results in almost the whole market being taken place by the DC motors.Unexpectedly,the vector control scheme has been proposed in 1970 s,which as a result decouples the parameters of the AC motors,and then they had the competence with DC motors in speed regulation area.After that,the AC motors developed immensely.Besides,in the procedure of the vector control scheme,one of the most crucial problems is the rotor's speed information.In traditional AC motors,the speed sensors should be established on them in order to obtain the rotor speed,which seems like in a very brief mode.However,the structure of the AC motors will be more complex after adding the speed sensors.In addition,sometimes the AC motors shall work in some extreme conditions.Based on this foundation,the thesis continues the sensor-less research,combining with the vector control scheme to regulate the AC motor.After analyzing the current research situation and the existing problems,the principles and the way of the vector control scheme has been illustrated.Also the methods to evaluate the rotor speed have been discussed too,the full-order state observer has been chosen to obtain the accurate speed information and its stability has also been proven in mathematics way.Finally,the mode of the AC motor is sketched in Matlab\Simulink,every part of the mode is verified in the software,which turns out to be the method can complete the control and speed regulation situation perfectly and promptly.At the same time,according to the error in low speed situation without speed sensor,the low frequency signal injection method is proposed as well.According to Matlab\Simulink,the method is verified in the software.Compared with the old existing control system,the response of the motor is faster and the structure of the motor is easier.