Power sag frequency converter restarting system based on PLC control

Abstract

The utility model relates to a power sag frequency converter restarting system based on PLC control, which comprises a voltage detection module, a PLC control system module and a human-computer interface module, and is characterized in that the voltage detection module is used for monitoring the voltage of a main loop in real time and judging the occurrence and recovery states of voltage sag according to voltage change characteristics; the PLC control system module is composed of a CPU, an I / O interface, a power supply and a communication interface, and is used for receiving and processing the shaking electric signal and controlling the frequency conversion equipment to reset and restart according to preset parameters and logic; and the human-computer interface module is used for monitoring main parameters of each frequency conversion device and the voltage detection module in real time, setting control parameters, querying historical records and carrying out necessary testing and operation. The system is provided with a voltage detection module, the voltage state of an electrical loop is monitored in a multi-point mode, accurate frequency converter fault information is obtained, and the production progress can be affected to the minimum extent.

Description

TECHNICAL FIELD

[0001] The utility model relates to frequency converter technical field, concretely is the system of restarting of frequency converter of shaking electricity based on PLC control. BACKGROUND

[0002] Frequency converter is the power control device that the on-off action of power semiconductor device is used to transform industrial frequency power into another frequency. In industrial control, low-voltage frequency converter is often used to control motor speed to meet the needs of energy saving and control.

[0003] "Shaking electricity" refers to the phenomenon that the grid voltage transient drop time is within 1.5 seconds and then restores to normal. Low-voltage frequency converter is sensitive to voltage variation, and the short-time undervoltage caused by grid shaking electricity in the system causes the frequency converter to report voltage fault trip. In large-scale industrial production process, due to the strong continuity of production process, the short-time shutdown of frequency conversion equipment caused by grid shaking electricity will interrupt the entire process flow and cause huge economic losses to enterprises.

[0004] The internal circuit of frequency converter is complex, and after shutdown due to failure, a large amount of time is needed to check each circuit one by one, which consumes a lot of time. Because the specific position is not specifically checked out, the factory is powered off, which affects the production efficiency.

[0005] In actual industrial application, in order to eliminate the influence of "shaking electricity", direct current support technology can be used for frequency converter, but the price is expensive, and the operation and production cost is too high for enterprises. CONTENT OF THE UTILITY MODEL

[0006] In view of the defects of the prior art, the utility model provides a kind of restarting system of frequency converter of shaking electricity based on PLC control, with the advantages of self-abnormal judgment, flexible parameter setting, strong expansibility, etc., solves the problem that frequency converter can be reset and started when shaking electricity occurs, and the problem that it is difficult to judge when abnormality occurs, and provides specific fault information for equipment.

[0007] A kind of restarting system of frequency converter of shaking electricity based on PLC control, including voltage detection module, PLC control module and man-machine interface module;

[0008] The main role of voltage detection module is to monitor the main circuit voltage in real time, detect voltage data, and judge the occurrence and recovery state of voltage sag according to voltage variation characteristics. Voltage data source can be one or more, and the voltage variation of a point and region is detected at the same time. Voltage detection module detects voltage sag, does not participate in the low-voltage protection of restarting motor, and the delay time TC of equipment is set as the delay time, and restarting can be carried out after the time.

[0009] The PLC control module comprises a CPU controller, an IO and a communication interface, voltage data detected by the voltage detection module can be read in the program of the PLC, and real-time monitoring and judgment are performed on the voltage data, when voltage sag occurs, voltage sag is judged; if there is no restart interrupt command within a preset time after the voltage sag, it is judged that the voltage sag condition has recovered;

[0010] When voltage sag occurs, and there is no restart interrupt command within a preset time, it is judged that the voltage sag condition has recovered, and the voltage sag amplitude and the voltage recovery amplitude can be set in the logic program of the PLC control module through the man-machine interface module as a judgment basis.

[0011] The man-machine interface module mainly monitors the main parameters of the frequency conversion equipment and the voltage detection module in real time, sets the control parameters, queries the historical records, tests and operates the necessary operations, and achieves intuitive and flexible system operation.

[0012] The voltage detection module can receive one or more voltage data sources when judging voltage sag and voltage recovery, and simultaneously detects voltage changes of one point or multiple regions; the PLC control system module will comprehensively judge the detection state according to multiple data sources and preset parameter settings.

[0013] The PLC control system module reads the data of the voltage detection module in real time, and monitors and judges the data; when voltage sag is detected, voltage sag is judged; if there is no restart interrupt command within a preset time after the voltage sag, it is judged that the voltage sag condition has recovered;

[0014] The judgment basis of the voltage sag amplitude and the voltage recovery amplitude can be set through the man-machine interface module and stored in the PLC control system, and is judged by the related program.

[0015] The man-machine interface module provides detailed operation interfaces and parameter setting options, and allows users to adjust system parameters and view system status according to actual needs.

[0016] Advantages of the utility model

[0017] Compared with the prior art, the utility model provides a power swing frequency converter restart system based on PLC control, which has the following advantages:

[0018] 1、The system can be expanded on the basis of the existing equipment PLC control system, and can be realized by increasing a general voltage detection module and modifying a logic program. The voltage detection module can judge the power swing condition, accurately obtain frequency converter fault information, execute reset restart for faults belonging to restartable, execute prohibition start for faults belonging to non-restartable, and alarm, so that the production progress is affected to the minimum.

[0019] 2. The system offers flexible parameter settings, ensuring both numerical values ​​and ranges meet practical debugging requirements. Settings are easily configured on a human-machine interface (HMI) module, such as a touch screen. This HMI module can connect to multiple PLC control modules, and the host computer can be easily configured in the control room via a network connection. Any authorized terminal with access to the network can also be configured. This makes centralized monitoring easy to implement and offers strong scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Fig. 1 This is a schematic diagram of the utility model process;

[0021] Fig. 2 This is a schematic diagram of parameter settings for the utility model. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] See also Figs. 1-2 , intelligent redundant power-shaking frequency conversion restart device, including a voltage detection module for real-time monitoring of the main circuit voltage, and judging the occurrence and recovery status of voltage sag based on the voltage change characteristics;

[0024] The PLC control system module, consisting of a CPU, I / O interface, power supply, and communication interface, is used to receive and process power-shaking signals (including voltage, status, faults, etc.), and reset and restart the frequency converter according to preset parameters and logic control;

[0025] The human-machine interface module is used to monitor the main parameters of each frequency conversion device and voltage detection module in real time, set control parameters, query historical records, and perform necessary tests and operations.

[0026] Through the above technical solution, the human-machine interface module parameter setting, the human-machine interface module sets the KV parameter setting, and can select the value to which the voltage sag is considered to be a voltage swing abnormality, and the value above which the voltage recovers is considered to be back to normal.

[0027] Specifically, when the voltage detection module determines voltage sag and voltage recovery, the voltage data may come from one or more sources, and the voltage change at a point or region may be detected simultaneously.

[0028] Through the technical scheme, parameters can be set, operation can be recorded, new frequency converter is further expanded, fault state and reset operation can be realized through communication with the frequency converter, and traditional hard-wire detection fault and reset operation are compatible.

[0029] Specifically, the PLC control module part reads the voltage data detected by the voltage detection module part, and performs real-time monitoring and judgment thereon, when voltage sudden drop occurs, the low voltage protection delay time TC is restored, and voltage fluctuation is judged. After the voltage is restored, the delay confirmation TY is confirmed for a period of time, and the voltage does not appear abnormally, the frequency converter is reset and restarted. If it exceeds the TE range and is not restored, specific alarm information is output according to the voltage detection point. The voltage sudden drop amplitude and the voltage recovery amplitude can be set to the PLC control program through the man-machine interface module as a judgment basis.

[0030] The threshold value of the detected voltage, the number of the detected voltage, and the type of the detected voltage are analog signal, the judgment rule of the temporary drop can be set, KV, TC, TY and TE can be independently set, and they can also be continuously and flexibly set.

[0031] Through the technical scheme, control instructions and state signals mainly include start, stop, run and reset, signals can also go through communication and hard-wire, communication and hard-wire can exist at the same time, and when they exist at the same time, the selection basis rule and processing mechanism when the signals deviate can be set.

[0032] In use, 1, power loss is detected, and the switching power output is output at the same time; 2, keep, no restart is allowed in this time; 3, if the voltage temporary drop is restored after keeping, the frequency converter can be reset and restarted; 4, after the power is restored, the delay confirmation is confirmed for a period of time; 5, if the TE time is not exceeded, the frequency converter is restarted, otherwise, an alarm is given, and no alarm is given before the next start.

[0033] The working principle of the utility model is:

[0034] When the frequency converter reports voltage fault and stops, the voltage detection module detects the main loop and control loop power voltage to judge whether the system has voltage fluctuation, sends a node signal to reset the frequency converter and start again. In this time, the speed of the motor can be controlled within 10%, so the required flow, pressure and other changes of the process will also be within 10% or within the allowable range. Thus, the continuous operation of the production equipment can be ensured, and the impact on production is minimized. If the voltage fluctuation time is exceeded, an alarm is sent to prompt the fault type and reason.

Claims

1. A PLC control-based power swing frequency converter restart system, comprising a voltage detection module, a PLC control system module, and a human-machine interface module, characterized in that: The voltage detection module is used to monitor the main circuit voltage in real time and determine the occurrence and recovery state of voltage sag according to voltage variation characteristics. The PLC control system module is composed of CPU, I / O interface, power supply, and communication interface, and is used to receive and process power swing signals and control the reset and restart of frequency conversion equipment according to preset parameters and logic. The human-machine interface module is used to monitor the main parameters of each frequency conversion equipment and the voltage detection module in real time, set control parameters, query historical records, and perform necessary tests and operations.

2. The PLC control-based fluctuation inverter restart system according to claim 1, characterized in that: When determining voltage sag and voltage recovery, the voltage detection module can receive one or more voltage data sources and detect voltage changes in one point or multiple regions at the same time. The PLC control system module will determine the detection state according to multiple data sources and preset parameter settings.

3. The PLC control-based fluctuation inverter restart system according to claim 1, characterized in that: The PLC control system module reads the data of the voltage detection module in real time and monitors and determines it. When voltage drops are detected, it is determined to be voltage sag. Within a certain preset time after voltage drop, if there is no restart interrupt command, it is determined that the voltage sag has recovered. The judgment basis for voltage drop amplitude and voltage recovery amplitude can be set through the human-machine interface module and stored in the PLC control system for judgment by related programs.

4. The PLC control-based fluctuation inverter restart system according to claim 1, characterized in that: The human-machine interface module provides detailed operation interface and parameter setting options, allowing users to adjust system parameters and view system status according to actual needs.

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