CN-122026776-A - Motor long-line driving system and reflected voltage suppression method

CN122026776ACN 122026776 ACN122026776 ACN 122026776ACN-122026776-A

Abstract

The application relates to a motor long-line driving system and a reflected voltage restraining method, which relate to the technical field of motors and comprise a current sensor, control equipment and an inverter, wherein the control equipment comprises a pulse width modulation module, a vector control module and a current sampling trigger, the current sensor is connected with a vector control module through an electric signal, the inverter comprises an inversion module, the inversion module is connected with the motor through a cable, when the current sampling trigger controls the current sensor to sample, a current signal is transmitted to the vector control module, the vector control module generates a vector voltage signal and transmits the vector voltage signal to the pulse width modulation module, the vector voltage signal is calculated and compared with a carrier wave, the pulse width value is used for driving the motor, the inversion module performs switching action to be an intersection point of the carrier wave and the pulse width value, the pulse width value is updated through the pulse width modulation module at a carrier wave extreme point, and the current sampling trigger point is delayed for a period of time T d compared with the carrier wave extreme point. The application has the advantage of reduced harmonic content of the current signal.

Inventors

Wen Shengpeng
ZHU SHUAI
ZHU TAO
XU SHUANGYIN

Assignees

新界泵业(浙江)有限公司

Dates

Publication Date: 20260512
Application Date: 20260401

Claims (7)

1. A motor long-line driving system is characterized by comprising a current sensor, control equipment and an inverter, wherein the control equipment comprises a pulse width modulation module, a vector control module and a current sampling trigger, the current sensor is in electric signal connection with the vector control module, the inverter comprises an inversion module, the inversion module is connected with a motor through a cable, when the current sampling trigger controls the current sensor to sample, a current signal is transmitted to the vector control module, the vector control module generates a vector voltage signal and transmits the vector voltage signal to the pulse width modulation module, the vector voltage signal is calculated and compared with a carrier wave, a modulation voltage is output and used for driving the motor, the inversion module performs switching action to be an intersection point of the carrier wave and the pulse width value, the pulse width value is updated through the pulse width modulation module at a carrier wave extreme value point, and the current sampling trigger point is delayed for a period of time T d compared with the carrier wave extreme value.
2. A motor long wire drive system according to claim 1, wherein T d is positively correlated with the length of the cable.
3. The motor long-line driving system according to claim 1, wherein the time period T d is not longer than the time period from the extreme point of the carrier wave to the next switching action of the inverter module.
4. A motor long wire drive system according to claim 1 wherein the pulse width modulation module comprises a pulse width modulator and a narrow pulse canceller.
5. A method for suppressing reflected voltage used in motor long-line drive system as in any one of claims 1-4 includes such steps as obtaining output phase voltage by vector control module, converting the output control voltage to obtain output phase voltage, calculating pulse width value, making an inverter module always have one phase in clamping state, injecting phase voltage modulation signal with alternate zero-sequence components, and comparing the amplitude of voltage modulation signal with that of carrier wave of motor control chip Calculating to obtain pulse width value The method comprises the steps of detecting a pulse width value and processing the pulse width value, namely when the current pulse width value is detected to generate a short-time narrow pulse driving waveform with high level or low level, adjusting the pulse width value so as to eliminate the narrow pulse generated by modulation, and the driving step comprises the step of comparing the adjusted pulse width value with a carrier signal to generate a motor driving signal and driving an inversion module to act.
6. A reflected voltage suppressing method according to claim 5, the method is characterized in that: , wherein, Corresponding to each phase of the motor; A threshold is determined for pulses greater than 0.
7. A reflected voltage suppressing method according to claim 6, the method is characterized in that: , wherein, The depth factor is eliminated for a narrow pulse, , For the voltage of the bus bar, The voltage output by the vector control module.

Description

Motor long-line driving system and reflected voltage suppression method Technical Field The application relates to the technical field of motors, in particular to a motor long-line driving system and a reflected voltage suppression method. Background In a motor long-line drive system, the inverter and the motor are connected by a long power transmission line (for example, the length is more than 100 m) instead of being directly connected. In applications such as underground mineral exploitation, deep well pump underground water intake, oil drilling, etc., the motor and the inverter can only be separately placed due to site limitations, which makes the motor long-line driving system widely used in these industries. Because of the wave reflection effect of the long power transmission line, the high-frequency pulse width modulation (Pulse Width Modulation, PWM) voltage waveform output by the inverter end is reflected at the motor end when transmitted to the motor end (the end of the long line connected with the motor), and the reflected voltage of the motor end is superposed with the incident voltage, so that very high overvoltage occurs at the motor end. Overvoltage at the motor end can lead to overvoltage breakdown damage of the stator coil, and in severe cases, breakdown short circuit damage of the transmission line. In order to protect a drive cable and a motor in a long-wire drive system and ensure stable operation of the whole drive system, a filter module (such as a reactor and a sine filter) is connected in series with an output end of an inverter (the end of the long wire is connected to the inverter) to inhibit reflected voltage. However, these filter modules are usually composed of high-power, large-volume and high-cost electronic filter devices, and these filter modules are huge in volume, severe in heat generation, troublesome to install and often have higher cost than the inverter itself. Disclosure of Invention In view of the shortcomings of the prior art, one of the purposes of the present application is to provide a motor long-wire driving system and a reflected voltage suppression method, which have the advantage of reduced harmonic content of current signals. The above object of the present application is achieved by the following technical solutions: The motor long-line driving system comprises a current sensor, control equipment and an inverter, wherein the control equipment comprises a pulse width modulation module, a vector control module and a current sampling trigger, the current sensor is in electric signal connection with the vector control module, the inverter comprises an inversion module, the inversion module is connected with a motor through a cable, when the current sampling trigger controls the current sensor to sample, a current signal is transmitted to the vector control module, the vector control module generates a vector voltage signal and transmits the vector voltage signal to the pulse width modulation module, a pulse width value is calculated and compared with a carrier wave, a modulation voltage is output and used for driving the motor, the inversion module performs switching action to be an intersection point of the carrier wave and the pulse width value, the pulse width value is updated at a carrier wave extreme point through the pulse width modulation module, and the current sampling trigger point is delayed for a period of time T d compared with the carrier wave extreme point. The present application may be further configured in a preferred example such that T d is positively correlated to the length of the long cable. In a preferred example, the application can be further configured that the time period of T d is not longer than the time from the extreme point of the carrier wave to the next time the inversion module generates the switching action. The present application may be further configured in a preferred example in that the pulse width modulation module includes a pulse width modulator and a narrow pulse canceller. The application also discloses a reflected voltage suppression method, which is applied to the motor long-line driving system and comprises the following steps of obtaining output phase voltage, processing and transforming the output control voltage of the vector control module to obtain the output phase voltage, calculating pulse width value, enabling the inverter module to always have one phase in a clamping state, injecting phase voltage modulation signals of alternating zero sequence components, and enabling the voltage modulation signals and the amplitude of carrier waves of a motor control chipCalculating to obtain pulse width valueThe method comprises the steps of detecting a pulse width value and processing the pulse width value, namely when the current pulse width value is detected to generate a short-time narrow pulse driving waveform with high level or low level, adjusting the pulse width value so as to eliminate the narrow pulse gener