Control method for speed measurement of asynchronous motor and device therefor

Abstract

A control method for speed measurement of an asynchronous motor and a device therefor adopt a controller for controlling a power inverter to output three-phase low-frequency symmetrical alternating current uu, uv and uw and apply a high-frequency exciting voltage uuH in the U-phase voltage; current transformers are respectively connected between the power inverter and V phase and between the power inverter and W phase of a stator winding of the asynchronous motor in series; the output ends of the two current transformers are respectively connected with a signal subtracter; the output end of the signal subtracter is sequentially connected with a signal filter and a system controller; the system controller is also connected with a speed setting signal device and a motor speed display; and the system controller controls the power inverter in real time according to the speed setting signal device through receiving the signal filtered by the signal filter and realizes the control of the speed of the asynchronous motor to be tested. Compared with the prior art, the invention does not need a speed sensor and has simple test method, high system reliability, quick response, good characteristic of low-speed dynamic response, high speed control accuracy and good application prospect.

Description

technical field [0001] The invention relates to an asynchronous motor speed measurement control method and a device thereof, and is especially suitable for speed detection and control of cage-type and winding-type asynchronous motors. Background technique [0002] In a high-performance asynchronous motor vector control system, the closed-loop control of the speed is generally indispensable; there are two known methods for measuring the speed of asynchronous motors: one is to use a mechanical speed sensor such as a photoelectric code disc and a tachogenerator. The motor speed is detected and the speed signal is fed back to obtain the speed sensor-based speed measuring device of the motor speed data; however, the mechanical speed sensor has installation problems and increases the maintenance workload of the system. The second is to estimate the speed by detecting physical quantities such as motor stator voltage and current to replace the speed sensorless speed measuring device...

AI Technical Summary

Problems solved by technology

[0002] In a high-performance asynchronous motor vector control system, the closed-loop control of the speed is generally indispensable; there are two known methods for measuring the speed of asynchronous motors: one is to use a mechanical speed sensor such as a photoelectric code disc and a tachogenerator. The motor speed is detected and the speed signal is fed back to obtain the speed sensor-based speed measuring device of the motor speed data; but the mechanical speed sensor has installation problems and increases the maintenance workload of the system

The second is to estimate the speed by detecting physical quantities such as the stator voltage and current of the motor to replace the speed sensorless speed measuring device of the speed sensor; although this system solves the problems caused by the mechanical speed sensor and reduces the system cost, the current speed The estimation method has a strong dependence on the motor parameters, and the calculation and control are more complex than the sensor system, the response is slow, and the low-speed dynamic response characteristics are poor

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