给水设备及其混合调速控制方法、装置和存储介质

Abstract

This invention discloses a water supply device and its mixing speed control method, apparatus, and storage medium. The water supply device includes a boiler, a high-pressure heater, a deaerator, and a first water supply device and at least one second water supply device connected in parallel. The first water supply device includes a first water supply pump, a hydraulic coupler, and a first minimum flow valve. The second water supply device includes a second water supply pump, a variable frequency motor, and a second minimum flow valve. The method includes: acquiring the boiler drum water level to determine a target speed based on the boiler drum water level, and determining a scoop tube opening command and a variable frequency command based on the target speed to control the scoop tube opening of the hydraulic coupler and control the operating frequency of the variable frequency motor, thereby ensuring that the boiler drum water level is within a preset water level range; and configuring the on / off flow thresholds of the first and second minimum flow valves according to the operating frequency of the variable frequency motor, so as to accurately control the on / off flow thresholds of the minimum flow valves and thereby improve the energy efficiency of the water supply device.

Description

Technical Field

[0001] This invention relates to the field of drive technology for boiler feedwater pumps in thermal power plants, and particularly to a mixed speed control method for feedwater equipment, a feedwater equipment, a computer-readable storage medium, and a mixed speed control device for feedwater equipment. Background Technology

[0002] Currently, most power plant feedwater pumps are configured in two main ways: a two-in-one-standby configuration, with each pump operating at 50% of the boiler capacity and using hydraulic coupling speed control; or a one-in-one-standby configuration, with each pump operating at 100% of the boiler capacity and using hydraulic coupling speed control. For the two-in-one-standby configuration, the typical feedwater pump modification plan involves modifying two pumps, retaining one with fixed-frequency hydraulic coupling control. This often results in one pump operating with variable frequency drive while the other operates with fixed-frequency hydraulic coupling speed control during normal operation. Furthermore, most power plant feedwater equipment includes the feedwater pumps and their recirculation pipelines. This pipeline returns to the deaerator after exiting the feedwater pump, and a minimum flow valve is installed on the recirculation pipeline to protect the feedwater pumps and prevent water temperature rise and vaporization during startup or extremely low-load operation.

[0003] However, due to the differences in response speed, linearity, and speed control accuracy between variable frequency speed regulation and hydraulic coupling speed regulation, they cause significant interference to automatic feedwater control. For example, they can cause huge fluctuations in the boiler drum water level, malfunction of boiler feedwater control, and prevent the unit from performing AGC (Automatic Generation Control). In severe cases, they may even cause boiler drum water level alarms, posing a huge threat to the normal operation of the power plant and the safety of the unit. Furthermore, the minimum flow valve will be opened when the feedwater pump is at a low speed, and it can only be closed again when the feedwater pump flow reaches more than 40%. This means that the feedwater pump operates under high power conditions for a long time during the period between the opening and closing of the minimum flow valve, resulting in increased feedwater pump energy consumption. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to propose a mixed speed control method for water supply equipment, which can synchronously adjust the speed of the first and second water supply pumps, ensuring the steam drum water level is within a preset range, while precisely controlling the opening and closing flow threshold of the minimum flow valve, thereby improving the energy efficiency of the water supply equipment.

[0005] The second objective of this invention is to provide a water supply device.

[0006] A third objective of this invention is to provide a computer-readable storage medium.

[0007] The fourth objective of this invention is to provide a mixing speed control device for a water supply system.

[0008] To achieve the above objectives, a first aspect of the present invention provides a method for mixed speed regulation control of a water supply system. The water supply system includes a boiler, a high-pressure heater, a deaerator, and a first water supply device and at least one second water supply device connected in parallel. The first water supply device includes a first water supply pump, a hydraulic coupler, and a first minimum flow valve. The first minimum flow valve is disposed on a circulation pipeline between the first water supply pump and the deaerator. The hydraulic coupler is connected to the first water supply pump. The second water supply device includes a second water supply pump, a variable frequency motor, and a second minimum flow valve. The variable frequency motor is connected to the second water supply pump. The second minimum flow valve is disposed on a circulation pipeline between the second water supply pump and the deaerator. The method includes: adjusting the speed of the first water supply pump by configuring the opening of the scoop tube of the hydraulic coupler, and adjusting the speed of the second water supply pump by configuring the operating frequency of the variable frequency motor; adjusting the speed of the second water supply pump by configuring the high-pressure heater... The water pumped by the first and second feedwater pumps is heated, and the hot water output from the high-pressure heater is convected through the boiler to output superheated steam; the boiler drum water level is obtained; a target rotational speed is determined based on the drum water level, and a scoop tube opening command and a frequency conversion command are determined based on the target rotational speed; the scoop tube opening of the hydraulic coupler is controlled based on the scoop tube opening command, and the operating frequency of the variable frequency motor is controlled based on the frequency conversion command, so that the rotational speeds of the first and second feedwater pumps are synchronously adjusted, and the drum water level is within a preset water level range; the on / off flow thresholds of the first and second minimum flow valves are configured according to the operating frequency of the variable frequency motor, so that the first minimum flow valve is controlled based on the on / off flow thresholds of the first minimum flow valve, and the second minimum flow valve is controlled based on the on / off flow thresholds of the second minimum flow valve.

[0009] According to the mixed speed control method for water supply equipment proposed in this embodiment of the invention, the speed of the first water supply pump is adjusted by configuring the opening degree of the scoop tube of the hydraulic coupler, and the speed of the second water supply pump is adjusted by configuring the operating frequency of the variable frequency motor. Then, the water pumped by the first and second water supply pumps is heated by a high-pressure heater, and the hot water output from the high-pressure heater is convected by a boiler to output superheated steam. Next, the boiler drum water level is obtained to determine the target speed, and the scoop tube opening command and variable frequency command are determined based on the target speed. The scoop tube opening degree of the hydraulic coupler is controlled according to the scoop tube opening command, and the operating frequency of the variable frequency motor is controlled according to the variable frequency command, so that the speeds of the first and second water supply pumps are synchronously adjusted, ensuring that the drum water level is within a preset range. Furthermore, the on / off flow thresholds of the first and second minimum flow valves are configured according to the operating frequency of the variable frequency motor, so that the first minimum flow valve is controlled according to its on / off flow threshold, and the second minimum flow valve is controlled according to its on / off flow threshold. Therefore, by synchronously adjusting the speed of the first and second feed water pumps to keep the steam drum water level within the preset range, the on / off flow threshold of the minimum flow valve is precisely controlled, thereby improving the energy efficiency of the water supply equipment.

[0010] In addition, the mixing speed control method for water supply equipment according to the above embodiments of the present invention may also have the following additional technical features:

[0011] According to one embodiment of the present invention, the switching flow threshold of the second minimum flow valve is positively correlated with the operating frequency of the variable frequency motor.

[0012] According to one embodiment of the present invention, the ratio of the switching flow threshold of the first minimum flow valve to the switching flow threshold of the second minimum flow valve is equal to the ratio of the rotational speed of the first water pump to the rotational speed of the second water pump.

[0013] According to one embodiment of the present invention, determining a target rotational speed based on the steam drum water level includes: obtaining a set steam drum water level of the boiler and determining a water level difference between the set steam drum water level and the steam drum water level; and determining the target rotational speed based on the water level difference.

[0014] According to one embodiment of the present invention, determining a target rotational speed based on the steam drum water level includes: acquiring the steam flow rate of the superheated steam and acquiring the hot water flow rate output by the high-pressure heater, and determining a flow rate difference based on the steam flow rate and the hot water flow rate; determining a target flow rate based on the steam drum water level, and determining the target rotational speed based on the target flow rate and the flow rate difference.

[0015] According to one embodiment of the present invention, configuring the switching flow threshold of the first minimum flow valve and the switching flow threshold of the second minimum flow valve according to the operating frequency of the variable frequency motor includes: determining the switching flow threshold of the second minimum flow valve according to the operating frequency of the variable frequency motor, and determining the piecewise linear function relationship between the operating frequency of the variable frequency motor and the switching flow threshold of the first minimum flow valve; and determining the switching flow threshold of the first minimum flow valve according to the operating frequency of the variable frequency motor and the piecewise linear function relationship.

[0016] According to one embodiment of the present invention, the first water pump is driven by a first electric motor through the hydraulic coupler. The hydraulic coupler includes a pump impeller, a turbine, a scoop tube, and a first speed-lifting gear. The input end of the first speed-lifting gear is connected to the output shaft of the first electric motor, and the output end of the first speed-lifting gear is connected to the pump impeller. The turbine is connected to the output shaft of the hydraulic coupler, and the output shaft of the hydraulic coupler is connected to the first water pump. The inner cavity of the pump impeller and the inner cavity of the turbine together form the working chamber of the hydraulic coupler. When the opening of the scoop tube of the hydraulic coupler is controlled according to the scoop tube opening command, the oil volume in the working chamber is adjusted through the scoop tube to adjust the rotational speed of the first water pump.

[0017] According to one embodiment of the present invention, the variable frequency motor includes a frequency converter and a second motor, the second motor being configured to drive the second water supply pump to operate, wherein, when controlling the operating frequency of the variable frequency motor according to the frequency conversion command, the operating speed of the second motor is adjusted to adjust the speed of the second water supply pump.

[0018] To achieve the above objectives, the water supply device proposed in the second aspect of the present invention includes a memory, a processor, and a mixed speed control program for the water supply device stored in the memory and executable on the processor. When the processor executes the mixed speed control program for the water supply device, it implements the mixed speed control method for the water supply device as described in the first aspect of the present invention.

[0019] According to the embodiments of the present invention, the water supply equipment can maintain synchronous adjustment of the rotation speed of the first water supply pump and the rotation speed of the second water supply pump by executing the mixed speed regulation control program of the water supply equipment. This ensures that the steam drum water level is within the preset water level range while accurately controlling the opening and closing flow threshold of the minimum flow valve, thereby improving the energy efficiency of the water supply equipment.

[0020] To achieve the above objectives, a computer-readable storage medium is provided in a third aspect embodiment of the present invention, which stores a mixed speed control program for a water supply device. When the mixed speed control program for the water supply device is executed by a processor, it implements the mixed speed control method for the water supply device as described in the first aspect embodiment of the present invention.

[0021] According to the computer-readable storage medium proposed in the embodiments of the present invention, by executing the mixed speed regulation control program of the water supply equipment stored thereon, the rotation speed of the first water supply pump and the rotation speed of the second water supply pump can be synchronously adjusted so that the steam drum water level is within the preset water level range, while accurately controlling the opening and closing flow threshold of the minimum flow valve, thereby improving the energy efficiency of the water supply equipment.

[0022] To achieve the above objectives, a fourth aspect of the present invention provides a mixed speed control device for a water supply system. The water supply system includes a boiler, a high-pressure heater, a deaerator, and a first water supply device and at least one second water supply device connected in parallel. The first water supply device includes a first water supply pump, a hydraulic coupler, and a first minimum flow valve. The first minimum flow valve is disposed on a circulation pipeline between the first water supply pump and the deaerator. The hydraulic coupler is connected to the first water supply pump. The second water supply device includes a second water supply pump, a variable frequency motor, and a second minimum flow valve. The variable frequency motor is connected to the second water supply pump. The second minimum flow valve is disposed on a circulation pipeline between the second water supply pump and the deaerator. The device includes: a control module for adjusting the speed of the first water supply pump by configuring the opening of the scoop tube of the hydraulic coupler, and for adjusting the speed of the second water supply pump by configuring the operating frequency of the variable frequency motor; the control module is also used to control the speed of the second water supply pump through the high-pressure heater. The water pumped by the first and second feedwater pumps is heated, and the hot water output from the high-pressure heater is convected through the boiler to output superheated steam; the acquisition module is used to acquire the steam drum water level of the boiler; the control module is also used to determine the target speed based on the steam drum water level, and to determine the scoop tube opening command and frequency conversion command based on the target speed, and to control the scoop tube opening of the hydraulic coupler based on the scoop tube opening command and to control the operating frequency of the variable frequency motor based on the frequency conversion command, so that the speed of the first and second feedwater pumps are kept synchronized and the steam drum water level is within a preset water level range; the control module is also used to configure the on / off flow threshold of the first minimum flow valve and the on / off flow threshold of the second minimum flow valve according to the operating frequency of the variable frequency motor, so that the first minimum flow valve is controlled according to the on / off flow threshold of the first minimum flow valve and the second minimum flow valve is controlled according to the on / off flow threshold of the second minimum flow valve.

[0023] According to the mixed speed control device for water supply equipment proposed in this embodiment of the invention, the control module adjusts the speed of the first water supply pump by configuring the opening of the scoop tube of the hydraulic coupler, and adjusts the speed of the second water supply pump by configuring the operating frequency of the variable frequency motor. Furthermore, the control module heats the water pumped by the first and second water supply pumps through a high-pressure heater, and the boiler convects the hot water output from the high-pressure heater to output superheated steam. Then, the acquisition module acquires the boiler drum water level, and the control module determines the target speed based on the drum water level and determines the scoop tube opening command based on the target speed. The system uses frequency conversion commands and controls the opening of the scoop tube of the hydraulic coupler based on the scoop tube opening command, and controls the operating frequency of the frequency conversion motor based on the frequency conversion command, so that the speed of the first and second feedwater pumps is synchronized and adjusted to keep the steam drum water level within a preset range. Furthermore, the control module configures the on / off flow thresholds of the first and second minimum flow valves based on the operating frequency of the frequency conversion motor, so that the first minimum flow valve is controlled according to its on / off flow threshold and the second minimum flow valve is controlled according to its on / off flow threshold. Thus, while keeping the speed of the first and second feedwater pumps synchronized and the steam drum water level within the preset range, the system precisely controls the on / off flow thresholds of the minimum flow valves, improving the energy efficiency of the water supply equipment.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a water supply device according to a specific embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of a first water supply device according to a specific embodiment of the present invention;

[0027] Figure 3 yes Figure 2 A magnified view of a portion of the hydraulic coupling O.

[0028] Figure 4 This is a schematic diagram of the structure of a second water supply device according to a specific embodiment of the present invention;

[0029] Figure 5 This is a flowchart illustrating the mixing speed control block of a water supply device according to an embodiment of the present invention.

[0030] Figure 6 This is a flowchart illustrating the mixing speed control block of a water supply device according to an embodiment of the present invention.

[0031] Figure 7 This is a flowchart illustrating the mixing speed control block of a water supply device according to an embodiment of the present invention.

[0032] Figure 8 This is a flowchart illustrating the mixing speed control block of a water supply device according to an embodiment of the present invention.

[0033] Figure 9 This is a block diagram of a mixing speed control device for a water supply system according to an embodiment of the present invention. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] The following description, with reference to the accompanying drawings, outlines an embodiment of the present invention: a method for controlling the mixed speed of a water supply device, a water supply device, a computer-readable storage medium, and a device for controlling the mixed speed of a water supply device.

[0036] Before introducing the mixing speed control method for water supply equipment, the water supply equipment, the computer-readable storage medium, and the mixing speed control device for water supply equipment according to embodiments of the present invention, let's first refer to the appendix. Figure 1-5 The specific structure of the water supply equipment according to an embodiment of the present invention will be described.

[0037] like Figures 1 to 4 As shown, the water supply equipment includes a boiler 10, a high-pressure heater 20, a deaerator 30, and a first water supply device 40 and at least one second water supply device 50 connected in parallel. The first water supply device 40 includes a first water supply pump 401, a hydraulic coupler 402, and a first minimum flow valve 403. The hydraulic coupler 402 is connected to the first water supply pump 401, and the first minimum flow valve 403 is located on the circulation pipeline between the first water supply pump 401 and the deaerator 30. The second water supply device 50 includes a second water supply pump 501, a variable frequency motor 502, and a second minimum flow valve 503. The variable frequency motor 502 is connected to the second water supply pump 501, and the second minimum flow valve 503 is located on the circulation pipeline between the second water supply pump 501 and the deaerator 30.

[0038] Furthermore, in some embodiments of the present invention, such as Figure 2 and Figure 3As shown, the first water pump 401 is driven by the first motor 41 through the hydraulic coupler 402. The hydraulic coupler 402 includes a pump wheel 421, a turbine 422, a scoop tube 423, and a first speed-lifting gear 424. The input end of the first speed-lifting gear 424 is connected to the output shaft of the first motor 41, and the output end of the first speed-lifting gear 424 is connected to the pump wheel 421. The turbine 422 is connected to one end of the output shaft of the hydraulic coupler 402, and the other end of the output shaft of the hydraulic coupler 402 is connected to the first water pump 401. The inner cavity of the pump wheel 421 and the inner cavity of the turbine 422 together form the working chamber of the hydraulic coupler 402. When the opening of the scoop tube of the hydraulic coupler 402 is controlled according to the scoop tube opening command, the oil volume in the working chamber is adjusted through the scoop tube to adjust the speed of the first water pump 401.

[0039] In other words, the first motor 41 can transmit its power to the first water pump 401 through the hydraulic coupler 402, thereby driving the first water pump 401 to run and thus driving the first water supply device 40 to supply water.

[0040] Specifically, when the first motor 41 drives the pump wheel 421 to rotate through the first speed-increasing gear 424, the working oil in the inner cavity of the pump wheel 421 will gain energy and be sent to the outer circumference of the pump wheel 421 under the action of inertial centrifugal force to form a high-speed oil flow. The high-speed oil flow on the outer circumference of the pump wheel 421 will form a resultant velocity with the radial relative velocity (the relative velocity between the high-speed oil flow and the center of the pump wheel 421) and the circumferential velocity of the pump wheel 421 outlet. It will rush into the radial flow channel inlet of the turbine 422 and flow along the radial flow channel of the turbine 422 to the inner cavity of the turbine 422. Then, the change in the oil flow torque will drive the turbine 422 to rotate. When the oil flow reaches the outlet of the turbine 422, it will form a resultant velocity with the radial relative velocity and the circumferential velocity of the turbine 422 outlet. It will flow into the radial flow channel of the pump wheel 421 and regain energy in the pump wheel 421. The aforementioned process is repeated to form a circulating flow circle of working oil in pump wheel 421 and turbine 422. Thus, pump wheel 421 can convert the mechanical work input by the first electric motor 41 into the kinetic energy of the oil, while turbine 422 can convert the kinetic energy of the oil into the output mechanical work, thereby transmitting the power of the first electric motor 41 to the first water pump 401 through hydraulic coupling 402.

[0041] The scoop tube 423 can adjust the speed of the first water pump 401 by adjusting the amount of oil in the working chamber. For example, when the scoop tube 423 is inserted to the deepest part of the working chamber of the hydraulic coupler 402 (the scoop tube opening is the smallest), the amount of oil in the circulation circle is the smallest, and the speed difference between the pump wheel 421 and the turbine 422 is large. At this time, the output speed of the hydraulic coupler 402 is the lowest. When the scoop tube 423 is inserted to the shallowest part of the working chamber of the hydraulic coupler 402 (the scoop tube opening is the largest), the amount of oil in the circulation circle is the largest, and the speed difference between the pump wheel 421 and the turbine 422 is small. At this time, the output speed of the hydraulic coupler 402 is the largest.

[0042] Furthermore, in some embodiments of the present invention, such as Figure 4 As shown, the variable frequency motor 502 includes a frequency converter 521 and a second motor 522. The second motor 522 is configured to drive the second water supply pump 501 to operate. When the operating frequency of the variable frequency motor 502 is controlled according to the frequency conversion command, the operating speed of the second motor 522 is adjusted to regulate the speed of the second water supply pump 501.

[0043] Specifically, in some embodiments of the present invention, a frequency conversion command can be determined based on the target speed, and the frequency converter 521 can be controlled to adjust the operating speed of the second motor 522 according to the frequency conversion command, so as to adjust the speed of the second water pump 501 through the second motor 522. That is to say, the second motor 522 can transmit power corresponding to the operating speed to the second water pump 501 to adjust the speed of the second water pump 501.

[0044] The frequency converter 521 can adjust the speed of the second water supply pump 501 by adjusting the operating speed of the second motor 522. For example, when the frequency converter 521 increases the operating speed of the second motor 522 according to the frequency conversion command, the power transmitted from the second motor 522 to the second water supply pump 501 increases, thereby increasing the speed of the second water supply pump 501. When the frequency converter 521 decreases the operating speed of the second motor 522 according to the frequency conversion command, the power transmitted from the second motor 522 to the second water supply pump 501 decreases, thereby decreasing the speed of the second water supply pump 501.

[0045] Figure 5 This is a flowchart illustrating the mixing speed control block of a water supply device according to an embodiment of the present invention.

[0046] Specifically, such as Figure 5 As shown, in some embodiments of the present invention, the mixing speed control method for a water supply device includes:

[0047] S101, the speed of the first water pump is adjusted by configuring the opening of the scoop tube of the hydraulic coupling, and the speed of the second water pump is adjusted by configuring the operating frequency of the variable frequency motor.

[0048] It is understood that, in the embodiments of the present invention, the speed of the first water pump can be adjusted by configuring the opening of the scoop tube of the hydraulic coupler, and the speed of the second water pump can be adjusted by configuring the operating frequency of the variable frequency motor, so that the speed of the first water pump and the speed of the second water pump are kept in sync.

[0049] S102 heats the water pumped by the first and second feed water pumps through a high-pressure heater, and outputs superheated steam by convection of the hot water output from the high-pressure heater through a boiler.

[0050] Understandably, the water pumped by the first and second feedwater pumps can be heated by a high-pressure heater, and the hot water output from the high-pressure heater can be convected by a boiler to output superheated steam, thereby ensuring the stable operation of the generator set and the stable power generation of the power plant.

[0051] S103, obtain the boiler drum water level.

[0052] Optionally, in some embodiments of the present invention, a steam drum water level detector can be installed at the steam drum water level of the boiler to obtain the real-time steam drum water level of the boiler.

[0053] S104 determines the target speed based on the steam drum water level, and determines the scoop tube opening command and frequency conversion command based on the target speed. It also controls the scoop tube opening of the hydraulic coupling based on the scoop tube opening command and controls the operating frequency of the variable frequency motor based on the frequency conversion command, so that the speed of the first feed water pump and the speed of the second feed water pump are synchronized and the steam drum water level is within the preset water level range.

[0054] Because the speed regulation range of the scoop tube opening is 30%–80%, meaning that the output speed of the hydraulic coupler does not change significantly when the scoop tube opening is between 0% and 30%, but is fully open when the scoop tube opening is above 80%, the speed regulation accuracy, response, and sensitivity are low when adjusting the scoop tube opening. This is especially problematic under heavy and light loads, where the feed pump speed may differ at the same scoop tube opening. In contrast, speed regulation by adjusting the operating frequency is not only adjustable but also has high linearity and sensitivity. Furthermore, when the first and second feed water devices... Simultaneous operation, with varying speed regulation accuracy, speed regulation response, and speed regulation sensitivity, can cause significant interference to the automatic feedwater control, resulting in large fluctuations in the steam drum water level and posing a significant threat to the normal operation of the power plant and the safety of the unit. Therefore, in the embodiments of this invention, the scoop tube opening command and frequency conversion command are determined based on the target speed. The scoop tube opening command is used to control the scoop tube opening of the hydraulic coupling, and the frequency conversion command is used to control the operating frequency of the variable frequency motor, so that the speed of the first feedwater pump and the speed of the second feedwater pump are kept synchronized, ensuring that the steam drum water level is within the preset water level range.

[0055] S105, configure the switching flow threshold of the first minimum flow valve and the switching flow threshold of the second minimum flow valve according to the operating frequency of the variable frequency motor, so as to control the first minimum flow valve according to the switching flow threshold of the first minimum flow valve and control the second minimum flow valve according to the switching flow threshold of the second minimum flow valve.

[0056] Since the switching threshold of the minimum flow valve is usually set based on the rated flow and rated speed of the water pump, under normal circumstances, the switching limit of the minimum flow valve is often to open when the water flow of the water pump is below 30% and close when the water flow of the water pump is above 40%. This results in increased power consumption of the water pump during the water flow period of 30% to 40%. Therefore, in the embodiments of the present invention, the switching flow thresholds of the first minimum flow valve and the second minimum flow valve are configured according to the operating frequency of the variable frequency motor, so as to control the first minimum flow valve according to the switching flow threshold of the first minimum flow valve and control the second minimum flow valve according to the switching flow threshold of the second minimum flow valve, thereby accurately controlling the switching flow threshold of the minimum flow valve and improving the energy efficiency of the system.

[0057] It should be understood that, in the embodiments of the present invention described above, the target rotational speed can be determined based on the boiler drum water level, and the scoop tube opening command and frequency conversion command can be determined based on the target rotational speed. The scoop tube opening of the hydraulic coupling is controlled based on the scoop tube opening command, and the operating frequency of the variable frequency motor is controlled based on the frequency conversion command. Furthermore, the on / off flow thresholds of the first minimum flow valve and the second minimum flow valve are configured according to the operating frequency of the variable frequency motor, so that the first minimum flow valve can be controlled based on its on / off flow threshold, and the second minimum flow valve can be controlled based on its on / off flow threshold. Thus, while maintaining synchronous adjustment of the rotational speeds of the first and second feedwater pumps, ensuring the boiler drum water level is within a preset range, the on / off flow thresholds of the minimum flow valves are precisely controlled, improving the energy efficiency of the feedwater equipment.

[0058] Furthermore, in some embodiments of the present invention, the switching flow threshold of the second minimum flow valve is positively correlated with the operating frequency of the variable frequency motor.

[0059] Specifically, the switching flow threshold of the second minimum flow valve changes with the operating frequency of the variable frequency motor. For example, the higher the operating frequency of the variable frequency motor, the higher the switching flow threshold of the configured second minimum flow valve; the lower the operating frequency of the variable frequency motor, the lower the switching flow threshold of the configured second minimum flow valve.

[0060] It should be noted that, in the process of configuring the switching flow threshold of the second minimum flow valve according to the operating frequency of the variable frequency motor, in order to avoid the second minimum flow valve being unable to open due to the low operating frequency of the variable frequency motor causing the configured switching flow threshold of the second minimum flow valve to be too low, in some embodiments of the present invention, the switching limit threshold of the second minimum flow valve can be set to 15% to ensure the stable operation of the second water pump.

[0061] Furthermore, since precise control of the switching flow threshold of the minimum flow valve is achieved, in the embodiments of the present invention, the switching limit threshold of the minimum flow valve can be further refined from the original 30% to 40% water flow range to 15% to 20% water flow range, so that the first water pump and the second water pump can continue to operate efficiently even during long-term low-load operation.

[0062] Furthermore, in some embodiments of the present invention, the ratio of the switching flow threshold of the first minimum flow valve to the switching flow threshold of the second minimum flow valve is equal to the ratio of the rotational speed of the first water pump to the rotational speed of the second water pump.

[0063] Specifically, the relationship between the switching flow threshold of the first minimum flow valve, the switching flow threshold of the second minimum flow valve, the rotational speed of the first feed pump, and the rotational speed of the second feed pump can be expressed by the following formula:

[0064] Q1 / Q2 = n1 / n2,

[0065] Where Q1 is the on / off flow threshold of the first minimum flow valve, Q2 is the on / off flow threshold of the second minimum flow valve, n1 is the speed of the first water pump, and n2 is the ratio of the speeds of the second water pump.

[0066] It should be understood that, in the embodiments of the present invention described above, the switching flow threshold of the second minimum flow valve can be configured according to the operating frequency of the variable frequency motor, thereby ensuring the reliable operation of the second water pump while reducing the energy consumption of the second water pump and improving the energy efficiency of the water supply equipment. Furthermore, the switching flow threshold of the first minimum flow valve can also be configured according to the switching flow threshold of the second minimum flow valve, the speed of the first water pump, and the speed of the second water pump, so that the switching flow threshold of the first minimum flow valve can also be adjusted based on the operating frequency of the variable frequency motor, thereby ensuring the reliable operation of the first water pump while reducing the energy consumption of the first water pump and improving the energy efficiency of the water supply equipment.

[0067] Furthermore, in some embodiments of the present invention, such as Figure 6 As shown, determining the target rotational speed based on the water level in the steam drum includes:

[0068] S201, obtain the set steam drum water level of the boiler, and determine the water level difference between the set steam drum water level and the steam drum water level.

[0069] Optionally, in some embodiments of the present invention, setting the steam drum water level may include a maximum steam drum water level and a minimum steam drum water level, and the steam drum water level of the boiler is the real-time steam drum water level detected by the steam drum water level detector A.

[0070] S202, determine the target rotational speed based on the water level difference.

[0071] In other words, in some embodiments of the present invention, the set steam drum water level of the boiler can be obtained, and the water level difference between the set steam drum water level and the steam drum water level can be determined. Then, the target speed can be determined based on the water level difference, thereby realizing single-impulse (steam drum water level) water level control.

[0072] It should be understood that, in the embodiments of the present invention described above, after determining the target rotational speed based on the water level difference between the set steam drum water level and the target rotational speed, the scoop tube opening command and the frequency conversion command can be determined based on the target rotational speed. The scoop tube opening command is used to control the scoop tube opening of the hydraulic coupling, and the frequency conversion command is used to control the operating frequency of the variable frequency motor. This ensures that the rotational speeds of the first and second feedwater pumps are synchronously adjusted, keeping the steam drum water level within the preset water level range. This ensures the reliable operation of the water supply equipment and the stable operation of the generator set.

[0073] Furthermore, in some embodiments of the present invention, such as Figure 7 As shown, determining the target rotational speed based on the water level in the steam drum includes:

[0074] S301, obtain the steam flow rate of superheated steam, obtain the hot water flow rate output by the high-pressure heater, and determine the flow rate difference based on the steam flow rate and the hot water flow rate.

[0075] S302, determine the target flow rate based on the water level in the steam drum, and determine the target rotational speed based on the target flow rate and the flow rate difference.

[0076] Optionally, in some embodiments of the present invention, such as Figure 1 As shown, a steam flow detector B can be installed in the superheated steam channel to obtain the steam flow rate of the hot steam. A flow detector C can be installed at the outlet of the high-pressure heater to obtain the hot water flow rate output by the high-pressure heater. A steam drum water level detector A can be installed at the boiler's steam drum water level to obtain the boiler's steam drum water level. The flow difference is determined based on the steam flow rate and the hot water flow rate. Then, the target flow rate is determined based on the steam drum water level, and the target speed is determined based on the target flow rate and the flow difference, thereby realizing three-impulse (steam drum water level, steam flow rate, and feedwater flow rate) water level control.

[0077] It should be understood that, in the embodiments of the present invention described above, after determining the target rotational speed based on the target flow rate (determined by the steam drum water level) and the flow difference (determined by the steam flow rate and the hot water flow rate), the scoop tube opening command and the frequency conversion command can be determined based on the target rotational speed. The scoop tube opening command is used to control the scoop tube opening of the hydraulic coupling, and the frequency conversion command is used to control the operating frequency of the variable frequency motor. This ensures that the rotational speeds of the first and second feedwater pumps are synchronously adjusted, keeping the steam drum water level within a preset range. This ensures the reliable operation of the water supply equipment and the stable operation of the generator set.

[0078] Furthermore, in some embodiments of the present invention, such as Figure 8 As shown, the switching flow thresholds of the first minimum flow valve and the second minimum flow valve are configured according to the operating frequency of the variable frequency motor, including:

[0079] S401, determine the switching flow threshold of the second minimum flow valve based on the operating frequency of the variable frequency motor, and determine the piecewise linear function relationship between the operating frequency of the variable frequency motor and the switching flow threshold of the first minimum flow valve.

[0080] Specifically, by conducting multiple experiments beforehand, the correspondence between the switching flow threshold of the first minimum flow valve and the operating frequency of the variable frequency motor can be obtained under the same pump speed and pump pressure. This correspondence can then be determined as a piecewise linear function relationship between the operating frequency of the variable frequency motor and the switching flow threshold of the first minimum flow valve.

[0081] S402, determine the switching flow threshold of the first minimum flow valve based on the operating frequency of the variable frequency motor and the piecewise linear function relationship.

[0082] Specifically, after obtaining the operating frequency of the variable frequency motor, the inverter command corresponding to the operating frequency of the variable frequency motor can be determined. Then, the switching flow threshold of the first minimum flow valve corresponding to the inverter command can be determined. For example, in a specific embodiment of the present invention, the correspondence between the inverter command and the switching flow threshold of the first minimum flow valve can be shown in Table 1 below. The correspondence can be used to indicate the switching flow threshold of the first minimum flow valve corresponding to the inverter command.

[0083] Table 1

[0084]

[0085] For example, the switching flow threshold corresponding to the inverter command can be obtained based on the inverter command corresponding to the inverter's operating frequency. For instance, assuming the inverter command corresponding to the inverter's operating frequency is less than 25Hz, the switching flow threshold of the first minimum flow valve is [Qn*(2.5 / 5)*30%, Qn*(2.5 / 5)*40%]. If the inverter command corresponding to the inverter's operating frequency is 30Hz, the switching flow threshold of the first minimum flow valve is [Qn*(3 / 5)*30%, Qn*(3 / 5)*40%], and so on. This will not be elaborated further here.

[0086] In summary, the mixed speed control method for water supply equipment proposed in this embodiment of the invention adjusts the speed of the first water supply pump by configuring the opening of the scoop tube of the hydraulic coupler, and adjusts the speed of the second water supply pump by configuring the operating frequency of the variable frequency motor. Then, the water pumped by the first and second water supply pumps is heated by a high-pressure heater, and the hot water output from the high-pressure heater is convected by a boiler to output superheated steam. Next, the boiler drum water level is obtained to determine the target speed, and the scoop tube opening command and variable frequency command are determined based on the target speed. The scoop tube opening of the hydraulic coupler is controlled according to the scoop tube opening command, and the operating frequency of the variable frequency motor is controlled according to the variable frequency command, so that the speeds of the first and second water supply pumps are synchronously adjusted, ensuring that the drum water level is within a preset range. Furthermore, the on / off flow thresholds of the first and second minimum flow valves are configured according to the operating frequency of the variable frequency motor, so that the first minimum flow valve is controlled according to its on / off flow threshold, and the second minimum flow valve is controlled according to its on / off flow threshold. Therefore, by synchronously adjusting the speed of the first and second feed water pumps to keep the steam drum water level within the preset range, the on / off flow threshold of the minimum flow valve is precisely controlled, thereby improving the energy efficiency of the water supply equipment.

[0087] Based on the mixed speed control method for water supply equipment in the foregoing embodiments of the present invention, the present invention also proposes a water supply equipment, including a memory, a processor, and a mixed speed control program for the water supply equipment stored in the memory and executable on the processor. When the processor executes the mixed speed control program for the water supply equipment, it implements the mixed speed control method for the water supply equipment as described in the foregoing embodiments of the present invention.

[0088] It should be noted that when the water supply equipment in the embodiments of the present invention runs the mixed speed regulation control program of the water supply equipment, it can realize the specific implementation method that corresponds one-to-one with the mixed speed regulation control method of the water supply equipment in the aforementioned embodiments of the present invention. In order to reduce redundancy, it will not be described again here.

[0089] In summary, the water supply equipment proposed in the embodiments of the present invention, by executing the mixed speed regulation control program of the water supply equipment, can keep the speed of the first water supply pump and the speed of the second water supply pump synchronized, so that the steam drum water level is within the preset water level range, while accurately controlling the opening and closing flow threshold of the minimum flow valve, thereby improving the energy efficiency of the water supply equipment.

[0090] Based on the mixed speed control method for water supply equipment in the foregoing embodiments of the present invention, the present invention also proposes a computer-readable storage medium storing a mixed speed control program for water supply equipment. When the mixed speed control program for water supply equipment is executed by a processor, it implements the mixed speed control method for water supply equipment as described in the foregoing embodiments of the present invention.

[0091] It should be noted that when the computer-readable storage medium of the present invention runs the mixed speed control program of the water supply equipment, it can implement specific implementation methods that correspond one-to-one with the mixed speed control method of the water supply equipment described in the aforementioned embodiments of the present invention. To reduce redundancy, these will not be repeated here.

[0092] In summary, the computer-readable storage medium proposed in the embodiments of the present invention, by executing the mixed speed control program of the water supply equipment stored thereon, can keep the speed of the first water supply pump and the speed of the second water supply pump synchronized, so that the steam drum water level is within the preset water level range, while accurately controlling the opening and closing flow threshold of the minimum flow valve, thereby improving the energy efficiency of the water supply equipment.

[0093] Based on the aforementioned method for mixing speed control of water supply equipment according to embodiments of the present invention, embodiments of the present invention also propose a mixing speed control device for water supply equipment, such as... Figure 9 As shown, the mixing speed control device for the water supply equipment includes: an acquisition module 10 and a control module 20.

[0094] The acquisition module 10 is used to acquire the boiler drum water level; the control module 20 is used to adjust the speed of the first feedwater pump by configuring the opening of the scoop tube of the hydraulic coupler, and to adjust the speed of the second feedwater pump by configuring the operating frequency of the variable frequency motor; the control module 20 is also used to heat the water pumped by the first and second feedwater pumps through the high-pressure heater, and to convect the hot water output from the high-pressure heater through the boiler to output superheated steam; the control module 20 is also used to determine the target speed according to the drum water level, and to determine the scoop tube opening command and the variable frequency command according to the target speed, and according to... The scoop tube opening command controls the opening of the scoop tube of the hydraulic coupler, and controls the operating frequency of the variable frequency motor according to the frequency conversion command, so that the speed of the first feed water pump and the speed of the second feed water pump are synchronized and adjusted so that the steam drum water level is within the preset water level range; the control module 20 is also used to configure the switching flow threshold of the first minimum flow valve and the switching flow threshold of the second minimum flow valve according to the operating frequency of the variable frequency motor, so as to control the first minimum flow valve according to the switching flow threshold of the first minimum flow valve and control the second minimum flow valve according to the switching flow threshold of the second minimum flow valve.

[0095] Optionally, the acquisition module 10 can be a steam drum water level detector installed at the steam drum water level of the boiler to acquire the steam drum water level of the boiler. The control module 20 can determine the target speed based on the steam drum water level, and then determine the scoop tube opening command and frequency conversion command based on the target speed. It can also control the scoop tube opening of the hydraulic coupling based on the scoop tube opening command and control the operating frequency of the variable frequency motor based on the frequency conversion command. The control module 20 can convert the scoop tube opening command and the frequency conversion command into control commands with a unified range, so that the speed of the first feedwater pump and the speed regulation response speed, speed regulation accuracy and speed regulation linearity of the second feedwater pump are consistent, so that the speed of the first feedwater pump and the speed of the second feedwater pump are kept in sync and the steam drum water level is within the preset water level range.

[0096] Furthermore, the control module 20 can configure the on / off flow threshold of the first minimum flow valve and the on / off flow threshold of the second minimum flow valve according to the operating frequency of the variable frequency motor, so as to control the first minimum flow valve according to the on / off flow threshold of the first minimum flow valve and control the second minimum flow valve according to the on / off flow threshold of the second minimum flow valve, thereby accurately controlling the on / off flow threshold of the minimum flow valve and improving the energy efficiency of the water supply equipment.

[0097] Furthermore, in some embodiments of the present invention, the switching flow threshold of the second minimum flow valve is positively correlated with the operating frequency of the variable frequency motor.

[0098] Furthermore, in some embodiments of the present invention, the ratio of the switching flow threshold of the first minimum flow valve to the switching flow threshold of the second minimum flow valve is equal to the ratio of the rotational speed of the first water pump to the rotational speed of the second water pump.

[0099] Furthermore, in some embodiments of the present invention, the control module 20 is also used to obtain the set steam drum water level of the boiler and determine the water level difference between the set steam drum water level and the steam drum water level; and determine the target rotational speed based on the water level difference.

[0100] Furthermore, in some embodiments of the present invention, the control module 20 is also configured to: acquire the steam flow rate of superheated steam, acquire the hot water flow rate output by the high-pressure heater, and determine the flow rate difference based on the steam flow rate and the hot water flow rate; determine the target flow rate based on the steam drum water level, and determine the target rotational speed based on the target flow rate and the flow rate difference.

[0101] Furthermore, in some embodiments of the present invention, the control module 20 is also configured to determine the switching flow threshold of the second minimum flow valve based on the operating frequency of the variable frequency motor, and determine the piecewise linear function relationship between the operating frequency of the variable frequency motor and the switching flow threshold of the first minimum flow valve; and determine the switching flow threshold of the first minimum flow valve based on the operating frequency of the variable frequency motor and the piecewise linear function relationship.

[0102] Furthermore, in some embodiments of the present invention, the first water pump is driven by a first electric motor through a hydraulic coupler. The hydraulic coupler includes a pump impeller, a turbine, a scoop tube, and a first speed-lifting gear. The input end of the first speed-lifting gear is connected to the output shaft of the first electric motor, and the output end of the first speed-lifting gear is connected to the pump impeller. The turbine is connected to the output shaft of the hydraulic coupler, and the output shaft of the hydraulic coupler is connected to the first water pump. The inner cavity of the pump impeller and the inner cavity of the turbine together form the working chamber of the hydraulic coupler. When controlling the opening of the scoop tube of the hydraulic coupler according to the scoop tube opening command, the oil volume in the working chamber is adjusted through the scoop tube to adjust the speed of the first water pump.

[0103] Furthermore, in some embodiments of the present invention, the variable frequency motor includes a frequency converter and a second motor, the second motor being configured to drive a second water supply pump, wherein, when controlling the operating frequency of the variable frequency motor according to the frequency conversion command, the operating speed of the second motor is adjusted to regulate the speed of the second water supply pump.

[0104] It should be noted that the specific implementation of the mixing speed control device 200 of the water supply equipment in this embodiment of the invention corresponds one-to-one with the specific implementation of the mixing speed control method of the water supply equipment in the aforementioned embodiment of the invention. To reduce redundancy, it will not be described again here.

[0105] In summary, the mixed speed control device for water supply equipment proposed in this embodiment of the invention regulates the speed of the first water pump by configuring the opening of the scoop tube of the hydraulic coupler through the control module, and regulates the speed of the second water pump by configuring the operating frequency of the variable frequency motor. Furthermore, the control module heats the water pumped by the first and second water pumps through a high-pressure heater, and the boiler convects the hot water output from the high-pressure heater to output superheated steam. Then, the acquisition module acquires the boiler drum water level, and the control module determines the target speed based on the drum water level, and determines the scoop tube opening based on the target speed. The system uses commands and frequency conversion commands to control the opening of the hydraulic coupling tube based on the command for the opening of the scoop tube, and to control the operating frequency of the variable frequency motor based on the command for the frequency conversion. This ensures that the speeds of the first and second feedwater pumps are synchronized, keeping the steam drum water level within a preset range. Furthermore, the control module configures the on / off flow thresholds for the first and second minimum flow valves based on the operating frequency of the variable frequency motor. This allows for control of the first and second minimum flow valves based on their respective on / off flow thresholds. Thus, while maintaining synchronized adjustment of the speeds of the first and second feedwater pumps to keep the steam drum water level within the preset range, the system also precisely controls the on / off flow thresholds of the minimum flow valves, improving the energy efficiency of the water supply equipment.

[0106] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0107] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0108] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for mixing speed control of a water supply equipment, characterized in that, The water supply equipment includes a boiler, a high-pressure heater, a deaerator, and a first water supply device and at least one second water supply device connected in parallel. The first water supply device includes a first water supply pump, a hydraulic coupler, and a first minimum flow valve. The first minimum flow valve is installed on the circulation pipeline between the first water supply pump and the deaerator. The hydraulic coupler is connected to the first water supply pump. The second water supply device includes a second water supply pump, a variable frequency motor, and a second minimum flow valve. The variable frequency motor is connected to the second water supply pump. The second minimum flow valve is installed on the circulation pipeline between the second water supply pump and the deaerator. The method includes: The speed of the first water pump is adjusted by configuring the opening of the scoop tube of the hydraulic coupler, and the speed of the second water pump is adjusted by configuring the operating frequency of the variable frequency motor. The high-pressure heater heats the water pumped by the first and second feed water pumps, and the boiler convects the hot water output from the high-pressure heater to output superheated steam. Obtain the steam drum water level of the boiler; The target speed is determined based on the steam drum water level, and the scoop tube opening command and frequency conversion command are determined based on the target speed. The scoop tube opening command is used to control the scoop tube opening of the hydraulic coupler, and the frequency conversion command is used to control the operating frequency of the variable frequency motor, so that the speed of the first feed water pump and the speed of the second feed water pump are kept synchronized and the steam drum water level is within the preset water level range. Configure the on / off flow threshold of the first minimum flow valve and the on / off flow threshold of the second minimum flow valve according to the operating frequency of the variable frequency motor, so as to control the first minimum flow valve according to the on / off flow threshold of the first minimum flow valve and control the second minimum flow valve according to the on / off flow threshold of the second minimum flow valve. The step of configuring the switching flow thresholds of the first minimum flow valve and the second minimum flow valve according to the operating frequency of the variable frequency motor includes: The switching flow threshold of the second minimum flow valve is determined based on the operating frequency of the variable frequency motor, and the piecewise linear function relationship between the operating frequency of the variable frequency motor and the switching flow threshold of the first minimum flow valve is determined. The switching flow threshold of the first minimum flow valve is determined based on the operating frequency of the variable frequency motor and the piecewise linear function relationship.

2. The method according to claim 1, characterized in that, The switching flow threshold of the second minimum flow valve is positively correlated with the operating frequency of the variable frequency motor.

3. The method according to claim 2, characterized in that, The ratio of the switching flow threshold of the first minimum flow valve to the switching flow threshold of the second minimum flow valve is equal to the ratio of the rotational speed of the first water pump to the rotational speed of the second water pump.

4. The method according to any one of claims 1-3, characterized in that, Determining the target rotational speed based on the steam drum water level includes: Obtain the set steam drum water level of the boiler, and determine the water level difference between the set steam drum water level and the steam drum water level; The target rotational speed is determined based on the water level difference.

5. The method according to claim 4, characterized in that, Determining the target rotational speed based on the steam drum water level includes: The steam flow rate of the superheated steam is obtained, and the hot water flow rate output by the high-pressure heater is obtained, and the flow rate difference is determined based on the steam flow rate and the hot water flow rate; The target flow rate is determined based on the water level in the steam drum, and the target rotational speed is determined based on the target flow rate and the difference between the flow rates.

6. The method according to any one of claims 1-3, characterized in that, The first water pump is driven by a first electric motor through the hydraulic coupler. The hydraulic coupler includes a pump impeller, a turbine, a scoop tube, and a first speed-lifting gear. The input end of the first speed-lifting gear is connected to the output shaft of the first electric motor, and the output end of the first speed-lifting gear is connected to the pump impeller. The turbine is connected to the output shaft of the hydraulic coupler, and the output shaft of the hydraulic coupler is connected to the first water pump. The inner cavity of the pump impeller and the inner cavity of the turbine together form the working chamber of the hydraulic coupler. When the opening of the scoop tube of the hydraulic coupler is controlled according to the scoop tube opening command, the oil volume in the working chamber is adjusted through the scoop tube to adjust the speed of the first water pump.

7. The method according to claim 6, characterized in that, The variable frequency motor includes a frequency converter and a second motor. The second motor is configured to drive the second water supply pump. When the operating frequency of the variable frequency motor is controlled according to the frequency conversion command, the operating speed of the second motor is adjusted to regulate the speed of the second water supply pump.

8. A water supply device, characterized in that, The device includes a memory, a processor, and a mixed speed control program for a water supply device stored in the memory and executable on the processor. When the processor executes the mixed speed control program for the water supply device, it implements the mixed speed control method for the water supply device according to any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, It stores a mixed speed control program for a water supply device, which, when executed by a processor, implements the mixed speed control method for a water supply device according to any one of claims 1-7.

10. A mixing speed control device for a water supply system, characterized in that, The water supply equipment includes a boiler, a high-pressure heater, a deaerator, and a first water supply device and at least one second water supply device connected in parallel. The first water supply device includes a first water supply pump, a hydraulic coupler, and a first minimum flow valve. The first minimum flow valve is installed on the circulation pipeline between the first water supply pump and the deaerator. The hydraulic coupler is connected to the first water supply pump. The second water supply device includes a second water supply pump, a variable frequency motor, and a second minimum flow valve. The variable frequency motor is connected to the second water supply pump. The second minimum flow valve is installed on the circulation pipeline between the second water supply pump and the deaerator. The device includes: The control module is used to adjust the speed of the first water pump by configuring the opening of the scoop tube of the hydraulic coupler, and to adjust the speed of the second water pump by configuring the operating frequency of the variable frequency motor. The control module is also used to heat the water pumped by the first feed water pump and the second feed water pump through the high-pressure heater, and to convect the hot water output by the high-pressure heater through the boiler to output superheated steam; The acquisition module is used to acquire the steam drum water level of the boiler; The control module is also used to determine the target speed according to the steam drum water level, and to determine the scoop tube opening command and frequency conversion command according to the target speed. It is also used to control the scoop tube opening of the hydraulic coupler according to the scoop tube opening command and to control the operating frequency of the variable frequency motor according to the frequency conversion command, so that the speed of the first feed water pump and the speed of the second feed water pump are kept in sync and the steam drum water level is within the preset water level range. The control module is further configured to configure the switching flow threshold of the first minimum flow valve and the switching flow threshold of the second minimum flow valve according to the operating frequency of the variable frequency motor, so as to control the first minimum flow valve according to the switching flow threshold of the first minimum flow valve and control the second minimum flow valve according to the switching flow threshold of the second minimum flow valve. The control module is further configured to determine the switching flow threshold of the second minimum flow valve based on the operating frequency of the variable frequency motor, and to determine the piecewise linear function relationship between the operating frequency of the variable frequency motor and the switching flow threshold of the first minimum flow valve; and to determine the switching flow threshold of the first minimum flow valve based on the operating frequency of the variable frequency motor and the piecewise linear function relationship.

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