Motor terminal voltage measuring instrument of alternating current frequency conversion motor

Abstract

The invention discloses a motor terminal voltage measuring instrument of an alternating current frequency conversation motor, and aims to solve the problems that if errors of motor terminal voltages which are acquired by converting collected direct current bus voltages are large or if the motor terminal voltages are directly measured, due to the characteristics of PWM square waves, high digital sampling frequency and high-speed digital signal processing are needed, and an ordinary controller can not meet the requirements. The measuring instrument (5) comprises a sensor, a sampling resistor, an AD sampling module and an FPGA. The input end of the sensor is electrically connected with the output end of an inverter (2), the output end of the sensor is electrically connected with one end of the sampling resistor, the other end of the sampling resistor is electrically connected with the signal input end of the AD sampling module, and the signal output end of the AD sampling module is connected with the input end of the FPGA through an I/O port. The input port of the measuring instrument is electrically connected with the output end of the inverter (2) through the sensor, and the output port of the measuring instrument is electrically connected with the input end of a motor controller (4) through the FPGA (field programmable gate array).

Description

technical field [0001] The invention relates to a measuring mechanism, more precisely, the invention relates to a machine terminal voltage measuring instrument of an AC variable frequency motor. Background technique [0002] With the rapid development of power electronics technology, AC variable frequency motors have been widely used in the industry. In the AC variable frequency motor system, the control algorithm is the core that determines the system performance, and the accuracy of the signal collected by the sensor will directly affect the effect of the control algorithm. Since the terminal voltage of the AC variable frequency motor is in the form of high-frequency and high-voltage PWM, it is currently impossible to achieve real-time measurement by the sensor. Therefore, the industry generally uses voltage sensors to measure the voltage at the input terminal of the inverter (such as figure 1 shown in Vdc) instead of the motor terminal voltage (as shown in figure 1 show...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the problems existing in the prior art that if the DC bus voltage is collected, the converted terminal voltage cannot accurately consider the voltage drop of the inverter, the error is large and if the motor terminal voltage is directly measured, due to the PWM square wave It requires extremely high digital sampling frequency and high-speed digital signal processing, which cannot be realized by ordinary controllers. A terminal voltage measuring instrument for AC variable frequency motors is provided.

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