Research On Torque-speed And Related Characteristics Of Asynchronous Motor

In the development stage of new motor products,a large number of motor performance tests are required to verify and improve the motor design parameters.The torque speed characteristic reflects whether the motor can start smoothly and run stably,and is an important characteristic that characterizes the mechanical performance of the motor.This topic studies a simple and effective method for measuring the torque and speed characteristics of the motor to meet the needs of small and medium-sized motor manufacturers.This subject uses the dynamic no-load method on the basis of analyzing the testing methods for torque and speed characteristics at home and abroad.This method is based on the principle of the torque tachometer method: the acceleration of the motor is proportional to the torque.By detecting the speed changes during the no-load start phase and the free deceleration phase,the acceleration is derived.According to the mechanical working principle of the motor,the torque and speed characteristics of the motor are calculated and analyzed.First,according to the principle of dynamic no-load method,the overall scheme of the motor torque and speed test system is designed.The STM32F407 microcontroller is used as the lower computer to realize the data collection and transmission;the upper computer adopts the MATLAB platform to realize the reception and processing of the data.At the same time,an incremental photoelectric encoder is used to convert the motor spindle speed signal into a pulse signal for capture by the input port of the microcontroller.Secondly,build a torque and speed test test platform,take asynchronous motors as the research object,design the start-stop and self-protection circuit of the test system,complete the selection of electrical components and circuit connection;design and process coupling parts,brackets and other parts Complete the mechanical connection between the incremental photoelectric encoder and the asynchronous motor.Then,the host computer processes the received data,calculates the moment of inertia and resistance torque according to the speed change data in the deceleration phase;combines the speed change data in the no-load start phase to obtain the output torque;uses the electromagnetic torque as the resistance The sum of the torque and the output torque draws the curve of the electromagnetic torque with the speed.Finally,in order to verify the accuracy of the dynamic no-load method,a verification test was conducted.The electromagnetic dynamometer system is used to perform load test on the tested motor to obtain test data at different load points.The data of different load stages of the dynamometer are compared with the test results of this subject.Obtained test results: The average value of the absolute value of the relative error does not exceed 3%,and the maximum error does not exceed 4%,indicating that the new simple and efficient torque test method suitable for small and medium-sized motor manufacturers used in this research is feasible and effective.This test method can also meet the application needs of enterprises.