High-pressure fan intelligent variable frequency soft start system and control method

Abstract

The application discloses a high-pressure fan intelligent variable-frequency soft starting system and a control method, and relates to the power distribution technical field.The soft starting system of the application is aimed at the high-pressure driving motor of the high-pressure fan, the voltage and frequency inputted to the driving motor are adjusted through a voltage transformation module, the variable-frequency voltage is smoothly increased through a soft starting module, and the driving motor is controlled to rotate from a basic value to a rated value step by step; the voltage transformation module and the soft starting module are started to work through a control module, the main power supply of the frequency converter is cut off after the voltage inputted to the driving motor through the voltage transformation module reaches the rated value, the fixed-frequency power supply of the high-voltage switch cabinet is turned on, the driving motor is controlled to run at a fixed frequency, and the soft starting of the high-pressure fan is completed.The starting process significantly reduces the impact of the starting current on the power grid, and avoids the tripping of the incoming line switch and the shutdown of the production.

Description

Technical Field

[0001] This invention relates to the field of power distribution technology, and in particular to an intelligent variable frequency soft start system and control method for high-voltage fans. Background Technology

[0002] High-pressure blowers are commonly used in industries such as oil and gas and chemical processing. They are natural gas refining equipment driven by electric motors of 3000kW or higher. The traditional direct starting method results in a large current surge, which has a significant impact on the power grid and motor equipment, and can easily cause incoming line switches to trip, equipment failures, and huge economic losses. Summary of the Invention

[0003] This invention provides an intelligent variable frequency soft start system and control method for high-pressure blowers to solve the problem of large direct starting current surges in high-pressure blowers, which can cause power grid and motor equipment failures.

[0004] This invention is achieved through the following technical solution:

[0005] In a first aspect, the present invention provides an intelligent variable frequency soft start system for high-pressure blowers, comprising:

[0006] A transformer module is used to regulate the voltage and frequency input to the drive motor of the high-pressure blower;

[0007] A soft start module is used to smoothly increase the voltage input to the drive motor through the transformer module, thereby controlling the rotation of the drive motor;

[0008] The control module is used to control the operation of the transformer module and the soft start module; and,

[0009] After the voltage input to the drive motor through the transformer module reaches the rated value, the main power supply of the frequency converter is cut off, and the fixed-frequency power supply of the high-voltage switchgear is turned on so that the drive motor can run at a fixed frequency.

[0010] This invention regulates the voltage and frequency of the input drive motor through a transformer module, and smoothly increases the input voltage and reduces the starting current through a soft-start module until the rated operating voltage of the drive motor is reached. At this point, the main frequency converter is disconnected, and the power supply is switched to a fixed frequency power supply, allowing the drive motor to operate at a fixed frequency. This achieves fixed-frequency operation of the high-voltage blower, realizing soft starting of the high-voltage blower. This significantly reduces the impact of the starting current on the power grid, reduces grid fluctuations and losses, reduces the mechanical and thermal stress on the motor, and extends the motor's service life. It also avoids the occurrence of incoming line switch tripping, solving the problem of large starting current impact of existing high-voltage blowers, which easily causes the incoming line switch to trip and shut down production, resulting in huge economic losses.

[0011] In a preferred embodiment, the transformer module includes a transformer and a frequency converter, wherein the transformer is used to regulate the voltage input to the drive motor, and the frequency converter is used to regulate the frequency input to the drive motor.

[0012] In a preferred embodiment, the transformer is a three-winding transformer. The high-voltage winding of the three-winding transformer is connected to the output of the high-voltage switchgear, the medium-voltage winding outputs voltage to the upper end of the frequency converter, and the low-voltage winding outputs voltage to power the intelligent frequency conversion soft-start system of the high-voltage fan.

[0013] In a preferred embodiment, the frequency converter is composed of multiple frequency conversion power units connected in series, with the frequency of each frequency conversion power unit gradually increasing from 0 Hz to 50 Hz and the voltage gradually increasing from 0 V to 1200 V.

[0014] In a preferred embodiment, the rated value is 10KV.

[0015] In a preferred embodiment, the transformer module further includes a reactor for limiting the rate of change of current.

[0016] In a preferred embodiment, the system further includes a setting module connected to the control module, which is used to set the parameters of the transformer module and the soft start module.

[0017] In a preferred embodiment, setting the parameters of the transformer module includes setting the rated power, rated voltage, and rated current of the drive motor; setting the parameters of the soft start module includes setting the starting current limit value and the starting ramp time.

[0018] In a preferred embodiment, the system further includes a detection module, which is used to detect the inlet and outlet flow rates of the high-pressure blower, and to start the transformer module through the control module when the inlet and outlet flow rates meet the start-up conditions.

[0019] In a preferred embodiment, the detection module further includes a first sensor group for detecting the electrical parameters of the drive motor, a second sensor group for detecting the electrical parameters of the transformer, and an analysis unit. The analysis unit analyzes abnormal situations based on the sensor data and reports them.

[0020] In a preferred embodiment, the system further includes an analysis module and an early warning module. When the analysis unit detects an abnormal situation, the early warning module issues an alarm.

[0021] A second aspect of the present invention provides a control method applied to the intelligent variable frequency soft start system for high-pressure blowers according to any one of the first aspects of the present invention, the control method comprising:

[0022] S1. Set the parameters for the transformer module and the soft starter module;

[0023] S2. After closing the high-voltage switch cabinet, the main power supply of the frequency converter is pre-charged to the pre-charge cabinet and then automatically supplied to the upper end of the transformer module.

[0024] S3. Intelligent detection of the inlet and outlet flow of the high-pressure blower; if the detected value meets the start-up conditions, the transformer module is automatically started.

[0025] S4. The transformer module adjusts the voltage and frequency, and the soft start module smoothly increases the voltage input to the transformer module to control the rotation of the drive motor of the high-pressure blower.

[0026] S5. After the voltage input to the drive motor in the transformer module reaches the rated value, the main power supply of the frequency converter is cut off, and the fixed frequency power supply of the high voltage switch cabinet is closed, so that the drive motor runs at a fixed frequency.

[0027] In a preferred embodiment, the parameters of the transformer module and the soft starter module are set as follows: the rated power, rated voltage and rated current of the drive motor in the transformer module are set; the starting current limit value and the starting ramp time of the soft starter module are set.

[0028] In a preferred embodiment, the control method further includes: real-time detection of the electrical parameters of the transformer module and the drive motor to obtain detection data; analysis of the detection data to determine whether either the transformer module or the drive motor is abnormal; and issuing an alarm when an abnormality is detected.

[0029] In a preferred embodiment, the anomaly includes overvoltage, overcurrent, and overheating.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] The voltage and frequency are adjusted by the transformer module. First, a low frequency and low voltage are output. The soft start module smoothly increases the starting frequency converter voltage to control the high-pressure blower to start rotating. When the frequency converter voltage reaches the rated operating voltage of the drive motor, the main frequency converter of the frequency converter is cut off and the power supply is switched to a fixed frequency power supply to drive the motor to run at a fixed frequency. This realizes the soft start of the high-pressure blower, which significantly reduces the impact of the starting current on the power grid and protects the safety of the power grid and the motor.

[0032] By using a frequency converter to adjust the motor's speed and power output according to actual needs, energy saving and consumption reduction can be achieved.

[0033] A three-winding transformer is used, with the medium-voltage winding supplying power to the upper end of the frequency converter and the low-voltage winding outputting power to the system.

[0034] The soft starter smoothly increases the frequency converter voltage and limits current changes through the reactor, thereby improving power grid quality;

[0035] Intelligent detection of motor and transformer parameters, analysis of abnormal situations, and assurance of equipment safety. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0037] Figure 1 This is a connection diagram of an intelligent variable frequency soft start control system for a high-pressure blower according to an embodiment of the present invention;

[0038] Figure 2 This is a flowchart of an intelligent variable frequency soft start control method for a high-pressure fan according to an embodiment of the present invention.

[0039] Attached diagrams and their markings: 1. Transformer module; 2. Soft start module; 3. Control module; 4. Setting module; 5. Detection module; 6. Motor detection unit; 7. Analysis unit; 8. Transformer detection unit; 9. Early warning module. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0041] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to other steps or units inherent in the device.

[0042] The terminology used in the various embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to limit the various embodiments of the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the invention pertain. The terms (such as those defined in a generally used dictionary) are to be interpreted as having the same meaning as in the context of the relevant technical field and are not to be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of the invention.

[0043] In a first aspect, embodiments of the present invention provide an intelligent variable frequency soft start system for high-pressure blowers, such as... Figure 1 The diagram shows its wiring schematic. The intelligent variable frequency soft start system includes a transformer module 1, a soft start module 2, and a control module. Transformer module 1 and soft start module 2 are connected to control module 3 and are controlled by control module 1. The upper end (high-voltage end) of transformer module 1 is connected to the high-voltage switchgear. After the high-voltage switchgear is closed, the inverter's main power supply is sent to the pre-charge cabinet for pre-charging. Once pre-charging is complete, power is automatically supplied to the upper end of the transformer module. The lower end (low-voltage end) of the transformer module is connected to the drive end of the drive motor, used to adjust the input voltage and frequency of the drive motor. In this embodiment, it is applied to the high-voltage motor driving the high-voltage blower. The transformer module first outputs a low frequency and low voltage to control the high-voltage blower to start rotating.

[0044] Soft starter module 2 employs a soft starter, which smoothly increases the voltage entering the transformer module, smoothly adjusts the frequency converter voltage, and controls the rotation of the drive motor. The core function of the soft starter is to control the output voltage and frequency ramp-up of the transformer module. By setting the starting current limit and starting ramp time of the soft starter, the starting current and the time required for the voltage to increase from the initial value to the rated voltage are limited, thus smoothly starting the motor and avoiding excessive impact on the power grid during startup.

[0045] Control module 3 uses a PLC control chip and connects to the transformer module and soft starter module. By sending control signals to these modules, it can control their startup. After the starting voltage increases from its initial value to its rated value, it cuts off the inverter's main power supply and connects the high-voltage switchgear's fixed-frequency power supply, causing the drive motor to run at a fixed frequency, i.e., the high-voltage fan to run at a fixed frequency, thus completing the soft start. In this invention, the inverter's main power supply refers to the inverter's main circuit power supply, that is, the main circuit power supply that powers the inverter. The switchgear's fixed-frequency power supply refers to the power frequency power supply circuit in the high-voltage distribution cabinet, typically 50Hz or 60Hz. After the motor completes the soft start, it switches to power frequency operation, meaning it is directly powered by the power grid.

[0046] The transformer module 3 can be a frequency converter or a transformer and a frequency converter. Specifically, the transformer module 3 includes a transformer and a frequency converter. The transformer is used to regulate the voltage input to the drive motor, and the frequency converter is used to regulate the frequency input to the drive motor.

[0047] In this embodiment, a suitable frequency converter and soft starter are selected based on the rated power, rated voltage and rated current of the drive motor.

[0048] Preferably, in this embodiment, the transformer is a three-turn transformer with three windings, wherein the high-voltage winding receives the output voltage of the high-voltage switchgear, the medium-voltage winding and the low-voltage winding serve as secondary windings, the output voltage of the medium-voltage winding supplies power to the drive motor, and the output voltage of the low-voltage winding supplies power to the system.

[0049] The three-winding transformer can convert the 10kV input voltage to 630V and 380V. The 630V is supplied to the upper end of the frequency converter to power the drive motor, and the 380V is converted to 220V to power the intelligent frequency conversion soft start system. After the input transformer voltage reaches the rated value of 10kV or the input drive motor voltage reaches the rated voltage of the drive motor of 630V, the main power supply of the frequency converter is cut off, the fixed frequency power supply of the high voltage switchgear is closed, and the high voltage fan operates at a fixed frequency.

[0050] Preferably, the frequency converter is composed of multiple frequency conversion power units connected in series, such as 8 or 9 units connected in series. The frequency of each frequency conversion power unit gradually increases from 0 Hz to 50 Hz, and the voltage gradually increases from 0 V to 1200 V.

[0051] Furthermore, the transformer module is also equipped with a reactor, which is connected in parallel to the output side of the transformer. The frequency converter voltage passes through the reactor, which limits the rate of change of current, improves the grid quality, and increases the energy utilization rate. When the voltage gradually rises to 10kV, the high-voltage switching cabinet intelligently disconnects the main power supply of the frequency converter.

[0052] Preferably, the intelligent variable frequency soft start system for high-voltage blowers also includes a setting module 4. This setting module includes an input device and a display, which are connected to the control module. Users can input setting parameters, view setting parameters, equipment status, and monitoring information. The control module can also preset transformer and soft starter parameters. Specifically, setting transformer parameters includes the rated power, rated voltage, and rated current of the drive motor; setting soft starter parameters includes the starting current limit and starting ramp time. The rated power, rated voltage, and rated current parameters of the high-voltage motor can also be set via the inverter's control panel.

[0053] Preferably, the intelligent variable frequency soft start system for high-pressure blowers also includes a detection module 5, which is connected to the transformer module 1. The detection module 5 includes a motor detection unit 6 and an analysis unit 7. The motor detection unit detects the inlet and outlet flow rates of the high-pressure blower, and the analysis module analyzes the inlet and outlet flow rates. When the start-up conditions are met, the transformer module is started.

[0054] The detection module intelligently monitors the inlet and outlet flow rates of the fan to ensure there are no blockages or other abnormalities before startup. For example, a large difference between the inlet and outlet flow rates may indicate a leak or blockage in the system, potentially causing startup problems. The detection device can use flow sensors or pressure sensors to determine whether the flow rate is normal based on the flow / pressure difference. Startup conditions can be set to a certain range for the flow / pressure difference or the rate of change of flow rate.

[0055] Preferably, the detection module 5 further includes a transformer detection unit 8, which consists of a set of sensors (first sensor group) for detecting electrical parameters such as transformer current, voltage, and temperature. The analysis unit 7 analyzes the real-time collected transformer detection values, analyzes abnormal situations, and reports them.

[0056] Preferably, the motor detection unit 6 further includes a set of sensors (second sensor group) for detecting electrical parameters such as current, voltage, and temperature of the drive motor, and the analysis unit 7 analyzes the real-time collected drive motor detection values, analyzes abnormal situations, and reports them.

[0057] Preferably, the intelligent variable frequency soft start system for high-pressure blowers also includes an alarm module 9, which is connected to the detection module 3 and issues an alarm when the analysis unit 7 detects an abnormality.

[0058] Abnormal situations include abnormal current, voltage, or temperature data of either the transformer or the drive motor, indicating overcurrent, overvoltage, or overheating.

[0059] Secondly, embodiments of the present invention provide a control method applied to the intelligent variable frequency soft start system for high-pressure blowers of the first aspect, see [link to relevant documentation]. Figure 2 The flowchart shown is for the intelligent variable frequency soft start control method for high-pressure blowers, which includes the following steps:

[0060] S1. Set the parameters for the transformer module and the soft start module.

[0061] This mainly includes setting the rated power, rated voltage, and rated current of the drive motor, as well as setting the starting current limit and starting ramp time of the soft starter to smoothly increase the starting voltage to the rated voltage of the drive motor, control the starting current, and protect the power grid and drive motor.

[0062] The parameters can be set through the control panel of the frequency converter or soft starter, or through the setting module.

[0063] S2. After closing the high-voltage switch cabinet, the main power supply of the frequency converter is pre-charged to the pre-charge cabinet and then automatically supplied to the upper end of the transformer module.

[0064] During soft start, first connect the main power supply of the high-voltage switchgear frequency converter to the pre-charge cabinet. After successful pre-charge, power is automatically supplied to the transformer. The transformer is a three-winding transformer (10kV to 630V and 10kV to 380V). 630V is supplied to the upper end of the frequency converter, and 380V to 220V provides power to the intelligent control system.

[0065] S3: Intelligently detects the inlet and outlet flow of the high-pressure blower. If the detected value meets the start-up conditions, the transformer module is automatically started.

[0066] In this embodiment, the motor detection unit intelligently detects the high-voltage motor lubrication oil system. When the inlet and outlet flow rates of the external fan meet the starting conditions, the transformer is automatically started.

[0067] S4. After the transformer module starts, adjust the input voltage and frequency. The soft start module smoothly increases the voltage input to the transformer module and controls the drive motor of the high-pressure blower to rotate.

[0068] During this process, the transformer module first outputs low frequency and low voltage to control the high-voltage fan to start rotating. The soft starter smoothly increases the frequency conversion voltage and the current is limited by the reactor until the frequency conversion voltage reaches the rated value.

[0069] S5. After the voltage input to the transformer module reaches the rated value for the drive motor, disconnect the main power supply of the frequency converter, close the fixed frequency power supply of the high voltage switch cabinet, and the drive motor will run at a fixed frequency.

[0070] When the frequency converter voltage gradually rises to the rated operating voltage of the motor, the high-voltage switching cabinet intelligently disconnects the main power supply of the frequency converter and closes the fixed-frequency power supply of the high-voltage switch cabinet, and the high-voltage motor runs at a fixed frequency.

[0071] Furthermore, the control method also includes: real-time detection of electrical parameters of the transformer module and drive motor, such as current, voltage, and temperature, obtaining detection data, analyzing whether the detection data is abnormal, and reporting abnormal data.

[0072] Furthermore, the control method also includes alarms for abnormal states, such as overcurrent, overvoltage, or overheating in either the transformer module or the drive motor.

[0073] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-pressure blower intelligent variable frequency soft start system, characterized in that, include: Transformer module (1) is used to adjust the voltage and frequency of the drive motor of the high-pressure blower. The soft start module (2) is used to smoothly increase the voltage input to the drive motor through the transformer module (1) and control the drive motor to rotate; The control module (3) is used to control the operation of the transformer module (1) and the soft start module (2); and, After the voltage input to the drive motor through the transformer module (2) reaches the rated value, the main power supply of the frequency converter is cut off and the fixed frequency power supply of the high voltage switch cabinet is closed so that the drive motor can run at a fixed frequency.

2. The intelligent variable frequency soft start system for high-pressure blowers according to claim 1, characterized in that, The transformer module (1) includes a transformer and a frequency converter. The transformer is used to regulate the voltage input to the drive motor, and the frequency converter is used to regulate the frequency input to the drive motor.

3. The intelligent variable frequency soft start system for high-pressure blowers according to claim 2, characterized in that, The transformer is a three-winding transformer. The high-voltage winding of the three-winding transformer is connected to the output of the high-voltage switchgear, the medium-voltage winding outputs voltage to the upper end of the frequency converter, and the low-voltage winding outputs voltage to power the intelligent frequency conversion soft start system of the high-voltage fan.

4. The intelligent variable frequency soft start system for high-pressure blowers according to claim 2, characterized in that, The frequency converter is composed of multiple frequency conversion power units connected in series. The frequency of each frequency conversion power unit gradually increases from 0 Hz to 50 Hz, and the voltage gradually increases from 0 V to 1200 V.

5. The intelligent variable frequency soft start system for high-pressure blowers according to any one of claims 1-4, characterized in that, The rated value is the rated operating voltage of the drive motor, and the drive motor is a high-voltage motor.

6. The intelligent variable frequency soft start system for high-pressure blowers according to claim 2, characterized in that, The transformer module (1) also includes a reactor for limiting the rate of change of current.

7. The intelligent variable frequency soft start system for high-pressure blowers according to claim 2, characterized in that, The system also includes a setting module (4), which is connected to the control module (3) and is used to set the parameters of the transformer module (1) and the soft start module (2).

8. The intelligent variable frequency soft start system for high-pressure blowers according to claim 7, characterized in that, Setting the parameters of the transformer module includes setting the rated power, rated voltage and rated current of the drive motor; setting the parameters of the soft start module (2) includes setting the starting current limit value and starting ramp time.

9. The intelligent variable frequency soft start system for high-pressure blowers according to any one of claims 1-4 and 6-7, characterized in that, The system also includes a detection module (5), which is used to detect the inlet and outlet flow rates of the high-pressure blower, and to start the transformer module (1) when the inlet and outlet flow rates meet the start-up conditions.

10. The intelligent variable frequency soft start system for high-pressure blowers according to claim 9, characterized in that, The detection module (5) further includes a first sensor group for detecting the electrical parameters of the drive motor, a second sensor group for detecting the electrical parameters of the transformer, and an analysis unit (7). The analysis unit (7) analyzes abnormal situations based on the sensor data and reports them.

11. The intelligent variable frequency soft start system for high-pressure blowers according to claim 10, characterized in that, The system also includes an early warning module (9), which issues an alarm when the analysis unit (7) analyzes that there is an abnormal situation.

12. A control method applied to the intelligent variable frequency soft start system for high-pressure blowers according to any one of claims 1-11, characterized in that, include: S1. Set the parameters for the transformer module and the soft starter module; S2. After closing the high-voltage switch cabinet, the main power supply of the frequency converter is pre-charged to the pre-charge cabinet and then automatically supplied to the upper end of the transformer module. S3. Intelligent detection of the inlet and outlet flow of the high-pressure blower; if the detected value meets the start-up conditions, the transformer module is automatically started. S4. The transformer module adjusts the voltage and frequency, and the soft start module smoothly increases the voltage input to the transformer module to control the rotation of the drive motor of the high-pressure blower. S5. After the voltage input to the drive motor in the transformer module reaches the rated value, the main power supply of the frequency converter is cut off, and the fixed frequency power supply of the high voltage switch cabinet is closed, so that the drive motor runs at a fixed frequency.

13. The control method according to claim 12, characterized in that, The parameters for setting the transformer module and the soft starter module include: setting the rated power, rated voltage, and rated current of the drive motor in the transformer module; and setting the starting current limit and starting ramp time of the soft starter module.

14. The control method according to claim 12, characterized in that, The control method further includes: real-time detection of the electrical parameters of the transformer module and the drive motor to obtain detection data; analysis of the detection data to determine whether either the transformer module or the drive motor is abnormal; and issuing an alarm when an abnormality is found.

15. The control method according to claim 14, characterized in that, The anomalies include overvoltage, overcurrent, and overheating.

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