Method for the automatic control of a water production plant

Abstract

The application provides an automatic control method of a water production device, the water production device comprising a first water production device and a second water production device downstream, the automatic control method comprising: obtaining a first outlet flow of all water production devices of the second water production device, obtaining a second outlet flow of a water production device to be adjusted, obtaining a first variable frequency frequency from the first outlet flow and the second outlet flow; obtaining a second variable frequency frequency according to a water tank liquid level of the water production device to be adjusted; obtaining a third variable frequency frequency according to the first variable frequency frequency and the second variable frequency frequency; outputting the third variable frequency frequency after limiting the amplitude or directly outputting as a final variable frequency frequency according to an inlet pressure value of the water production device to be adjusted, and controlling a water pump by the final variable frequency frequency. Thus, the water pump variable frequency frequency of each stage of the water production device is sequentially adjusted, dynamic water balance is realized, and the water tank liquid level and the inlet pressure of the water production device are stable.

Description

Technical Field

[0001] This invention relates to the field of water purification equipment control technology, and in particular to an automatic control method for water purification equipment. Background Technology

[0002] In existing thermal power plant water treatment chemical equipment, when water treatment is automatically controlled, the control methods between various processes are achieved by operators through multiple observations and trials, fixing the frequency of the frequency converter of each equipment pump at a certain value, thereby achieving the water balance of the water treatment system.

[0003] Manually setting the frequency of the water pump inverter requires operators to make multiple attempts to achieve a rough water balance in the system. Furthermore, after a period of operation, the equipment's output gradually decreases due to scaling and other factors, necessitating further adjustment of the inverter frequency for the feed water pump or high-pressure pump.

[0004] Therefore, the existing control methods for water purification equipment cannot achieve automated dynamic adjustment of the equipment, and the setting of adjustment parameters also depends on the operator's experience, resulting in a large error. Summary of the Invention

[0005] This invention provides an automatic control method for a water purification device, which enables sequential adjustment of the frequency conversion of water pumps at each stage of the water purification device to achieve dynamic water balance, while stabilizing the water level in the water tank and the inlet pressure of the water purification device.

[0006] According to a first aspect of the present invention, an automatic control method for a water purification device is provided, the water purification device comprising a first water purification device and a second water purification device; the first water purification device comprising a two-stage reverse osmosis device, and the second water purification device comprising an electro-deionization device; or, the first water purification device comprising a first-stage reverse osmosis device, and the second water purification device comprising a two-stage reverse osmosis device or an electro-deionization device; or, the first water purification device comprising an ultrafiltration device, and the second water purification device comprising a first-stage reverse osmosis device, a two-stage reverse osmosis device, or an electro-deionization device; each of the water purification devices comprising a water tank and at least one water purification unit, each water purification unit corresponding to at least one water pump; the automatic control method comprising:

[0007] Obtain the first outlet flow rate of all water-making devices in the second water-making equipment, obtain the second outlet flow rate of the water-making device to be adjusted, and obtain the first frequency conversion frequency based on the first and second outlet flow rates; wherein, the water-making device to be adjusted is: the water-making device in the first water-making equipment whose water pump frequency conversion frequency is to be adjusted.

[0008] The second frequency converter is obtained based on the water tank level of the water purification device to be adjusted.

[0009] The third frequency is obtained based on the first and second frequency conversion frequencies;

[0010] Based on the inlet pressure of the water purification device to be adjusted, the third frequency converter is limited and then output as the final frequency converter, or the third frequency converter is directly output as the final frequency converter.

[0011] The final frequency of the variable frequency drive is input to the water pump of the water production device to be adjusted in order to control the water pump.

[0012] Optionally, obtaining the first outlet flow rate of all water purification devices in the second water purification equipment, obtaining the second outlet flow rate of the water purification device to be adjusted, and obtaining the first frequency conversion frequency based on the first and second outlet flow rates, includes:

[0013] The sum of the real-time flow rates of all water purification devices at the outlets of all the second water purification devices is obtained and divided by the number of water purification devices in the first water purification device. The calculation result is rate-limited to obtain the first semaphore.

[0014] The real-time flow rate at the outlet of the water treatment device to be adjusted is obtained, and a first-order hysteresis filter is performed to obtain the second signal quantity.

[0015] Using the first signal quantity as the set value and the second signal quantity as the measured value, a difference calculation is performed, and a proportional-integral-derivative adjustment calculation is performed to obtain the first frequency conversion frequency.

[0016] Optionally, the second frequency converter is obtained based on the water tank level of the water purification device to be adjusted, including:

[0017] Obtain the water tank level of the water-making device to be adjusted, and obtain the second frequency conversion frequency according to a preset function;

[0018] The preset function includes the frequency function of the water pump inverter of the water production device to be adjusted, corresponding to the water level in the water tank of the first water production device.

[0019] Optionally, obtaining the third frequency conversion frequency based on the first and second frequency conversion frequencies includes:

[0020] The first frequency conversion frequency is added to the second frequency conversion frequency to obtain the third frequency conversion frequency.

[0021] Optionally, based on the inlet pressure of the water purification device to be adjusted, the third frequency converter is limited and output as the final frequency converter, including:

[0022] The inlet pressure signal of the water purification device to be adjusted is obtained. When the inlet pressure signal is not damaged, and when the inlet pressure is higher than the first preset threshold or lower than the second preset threshold, the third frequency is limited after a first preset time interval, and the fourth frequency is output after the limit is reached.

[0023] The fourth frequency conversion frequency is the final frequency conversion frequency;

[0024] The signal quality is not compromised, including: the measurement circuit is not disconnected, communication is not faulty, and the signal is not out of range.

[0025] Optionally, the step of directly outputting a third frequency converter as the final frequency converter based on the inlet pressure of the water purification device to be adjusted includes:

[0026] The inlet pressure signal of the water purification device to be adjusted is obtained. When the inlet pressure signal is not damaged, and the inlet pressure is less than the first preset threshold and greater than the second preset threshold, the third frequency conversion frequency is directly output as the final frequency conversion frequency.

[0027] The signal quality is not compromised, including: the measurement circuit is not disconnected, communication is not faulty, and the signal is not out of range.

[0028] Optionally, it also includes: switching to manual control mode when parameter acquisition fails;

[0029] When the deviation between the set value and the measured value is greater than the third preset threshold, switch to manual control mode;

[0030] When the difference between the final frequency command given to the variable frequency device and the frequency feedback signal of the water pump variable frequency device to be adjusted exceeds the fourth preset threshold, switch to manual control mode.

[0031] The manual control mode includes manually inputting the frequency of the water pump of the water treatment device to be adjusted.

[0032] Optionally, if the parameter acquisition fails, the system switches to manual control mode, including: when acquiring the outlet flow rate of the water production device in the second water production device and the first water production device, if the acquired signal has poor quality, the system switches to manual control mode.

[0033] When obtaining the frequency feedback signal of the water pump inverter of the water treatment device to be adjusted, if the obtained signal is of poor quality, switch to manual control mode.

[0034] The acquired signal quality defects include: measurement circuit disconnection, communication failure, and signal over-range.

[0035] Optionally, when the deviation between the set value and the measured value exceeds a third preset threshold, the system switches to manual control mode, including:

[0036] After obtaining the set value and the measured value, when the difference between the set value and the measured value is greater than the third preset threshold, switch to manual control mode.

[0037] Optionally, when the difference between the final frequency command given and the frequency feedback signal of the water pump inverter of the water treatment device to be adjusted exceeds a fourth preset threshold, the system switches to manual control mode, including:

[0038] After the water pump of the water production device to be adjusted obtains the final frequency conversion command, the frequency feedback signal of the frequency converter of the first water production device is obtained. When the difference between the frequency feedback signal and the final frequency conversion command exceeds the fourth preset threshold, the system switches to manual control mode.

[0039] This invention provides an automatic control method for a water purification device. A first variable frequency drive (VFD) is determined based on the outlet flow rate of the downstream device in the water purification process and the device's own outlet flow rate. Simultaneously, a second VFD is determined based on the water tank capacity of the device to be adjusted. The first and second VFDs together determine a third VFD. The final VFD is determined by directly outputting or limiting the output of the third VFD based on the inlet pressure of the water purification device. This achieves sequential adjustment of the pump VFD frequencies of each stage of the water purification equipment, ultimately achieving dynamic water balance while stabilizing the water tank level and inlet pressure. This method enables automated control of the water purification equipment, reduces the need for manual intervention, and improves the automation level of the production process.

[0040] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of a water production process provided in an embodiment of the present invention;

[0043] Figure 2 This is a flowchart of an automatic control method for a water purification device provided in an embodiment of the present invention;

[0044] Figure 3 This is a flowchart of an automatic control method for another water purification device provided in an embodiment of the present invention;

[0045] Figure 4 This is a flowchart of an automatic control method for another water purification device provided in an embodiment of the present invention;

[0046] Figure 5 This is a flowchart of an automatic control method for another water purification device provided in an embodiment of the present invention;

[0047] Figure 6 This is a flowchart of an automatic control method for another water purification device provided in an embodiment of the present invention;

[0048] Figure 7 This is a flowchart of an automatic control method for another water purification device provided in an embodiment of the present invention;

[0049] Figure 8 This is a flowchart of an automatic control method for another water purification device provided in an embodiment of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0051] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0052] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0053] Figure 1 This is a schematic diagram of a water production process provided in an embodiment of the present invention, such as... Figure 1As shown, the water purification process includes an electro-deionization unit 101, a secondary reverse osmosis unit 102, a primary reverse osmosis unit 103, and an ultrafiltration unit 104. Each water purification unit includes a water tank and at least one water purification device, with each device corresponding to at least one water pump. It also includes corresponding auxiliary systems, primarily dosing systems for each stage of the process, self-cleaning filters, cleaning pumps, and other equipment.

[0054] For example, the electro-deionization device 101 includes at least one water tank and n (n≥1) electro-deionization devices: #1 electro-deionization device, #2 electro-deionization device, ..., #n electro-deionization device. Each electro-deionization device corresponds to at least one water pump.

[0055] exist Figure 1 In the provided water production process, raw water is stored in industrial / fire-fighting water tanks or clear water tanks, and then sequentially treated by ultrafiltration, primary reverse osmosis, secondary reverse osmosis, and electro-deionization equipment. The final product water is prepared after treatment by the electro-deionization equipment at the end of the system. The frequency of the water pump inverter for each water production unit needs to be adjusted accordingly to achieve dynamic water balance in the entire chemical water production system.

[0056] Figure 2 A flowchart of an automatic control method for a water purification device provided in an embodiment of the present invention is shown below. Figure 2 As shown, the automatic control method includes:

[0057] S201, obtain the first outlet flow rate of all water-making devices in the second water-making equipment, obtain the second outlet flow rate of the water-making device to be adjusted, and obtain the first frequency conversion frequency based on the first and second outlet flow rates.

[0058] Combination Figure 1 and Figure 2 The water treatment equipment includes a first water treatment device and a second water treatment device.

[0059] When the first water purification unit includes a two-stage reverse osmosis unit and the second water purification unit includes an electro-deionization unit; or, the first water purification unit includes a first-stage reverse osmosis unit and the second water purification unit includes a second-stage reverse osmosis unit or an electro-deionization unit; or, the first water purification unit includes an ultrafiltration unit and the second water purification unit includes a first-stage reverse osmosis unit, a second-stage reverse osmosis unit, or an electro-deionization unit; that is, in Figure 1 In the given water treatment process, the second water treatment device is the downstream device of the first water treatment device.

[0060] The water production device to be adjusted is: the water production device in the first water production equipment whose frequency of the water pump variable frequency is to be adjusted.

[0061] In step S201, if the frequency of the pump to be adjusted in the first water treatment equipment needs to be adjusted, the outlet flow rate of the downstream water treatment equipment and the outlet flow rate of the water treatment device to be adjusted are obtained. Based on the outlet flow rate of the downstream water treatment equipment, the frequency of the pump of the water treatment device to be adjusted is adjusted so that the outlet flow rate of each device is basically consistent, and the entire chemical water treatment system achieves a dynamic water balance.

[0062] S202, Obtain the second frequency conversion frequency based on the water tank level of the water purification device to be adjusted;

[0063] Based on the water tank level of the first water treatment device, the frequency of the inverter of the water pump of the water treatment device to be adjusted corresponding to this water level is obtained as the second frequency conversion frequency.

[0064] Optionally, the normal operating water level (manually calibrated) of the outlet water tank of each water treatment equipment is used as a reference. The deviation between the water tank level during operation and the normal operating water level is used as the feedforward of the automatic circuit of the water supply pump of the equipment. The larger the deviation, the greater the effect, and vice versa. The feedforward is input to the first frequency converter to adjust the first frequency converter.

[0065] S203, the third frequency is obtained based on the first frequency and the second frequency;

[0066] After obtaining the first and second frequency conversion frequencies, the first and second frequency conversion frequencies are mixed. Optionally, the first and second frequency conversion frequencies are added together so that the final third frequency conversion frequency takes into account the dynamic water balance of water production and the stability of the water level in the tank of the first water production equipment.

[0067] S204, based on the inlet pressure value of the water purification device to be adjusted, the third frequency converter is limited and then output as the final frequency converter, or the third frequency converter is directly output as the final frequency converter.

[0068] Water purification devices have specific operating pressure requirements. Excessive pressure can damage the device or filter membrane; insufficient pressure can result in no water output or a very low water flow. Correspondingly, when the inlet pressure of the water purification device exceeds a first threshold or falls below a second threshold, the frequency converter of the water pump needs to be limited to ensure the internal operating pressure of the device. When the inlet pressure is between the first and second thresholds, a third frequency converter can be directly output as the final frequency converter. The first threshold is less than the second threshold.

[0069] S205, the final frequency of the variable frequency drive is input to the water pump of the water treatment device to be adjusted in order to control the water pump;

[0070] After calculating the final frequency according to steps S201-S204, the final frequency is input to the water pump of the water production device to be adjusted for control.

[0071] Optionally, if the first water production equipment includes multiple water production devices, and each of the multiple water production devices corresponds to a water pump, then the water pump of each water production device is adjusted accordingly in sequence.

[0072] This invention provides an automatic control method for a water purification device. A first variable frequency drive (VFD) is determined based on the outlet flow rate of the downstream device in the water purification process and the device's own outlet flow rate. Simultaneously, a second VFD is determined based on the water tank capacity of the device to be adjusted. The first and second VFDs together determine a third VFD. The final VFD is determined by directly outputting or limiting the output of the third VFD based on the inlet pressure of the water purification device. This achieves sequential adjustment of the pump VFD frequencies of each stage of the water purification equipment, ultimately achieving dynamic water balance while stabilizing the water tank level and inlet pressure. This method enables automated control of the water purification equipment, reduces the need for manual intervention, and improves the automation level of the production process.

[0073] Figure 3 This is a flowchart of an automatic control method for another water purification device provided in an embodiment of the present invention. Figure 4 This is a flowchart of an automatic control method for a water purification device provided in another embodiment of the present invention, as shown below. Figure 3 , 4 As shown, the automatic control method includes:

[0074] S301, obtain the sum of the real-time flow rates of all water purification devices at the outlets of all second water purification devices and divide it by the number of water purification devices in the first water purification device. Apply rate limiting to the calculation result to obtain the first semaphore.

[0075] Combination Figure 3 , Figure 4 As shown, when the second water production equipment includes n water production devices and the first water production equipment includes m water production devices, the sum of the outlet flow rates of the n water production devices of the second water production equipment is obtained and divided by m. The calculation result is rate-limited to obtain the first signal quantity.

[0076] Among them, the rate limit is to limit the real-time rate of change of the parameter to prevent frequent and large fluctuations in the parameter from affecting the control loop and thus affecting the stability of the control loop.

[0077] S302, obtain the real-time flow rate of the outlet of the water treatment device to be adjusted, and perform first-order hysteresis filtering to obtain the second signal quantity;

[0078] Specifically, the outlet flow rate of the water treatment device to be adjusted in the first water treatment equipment is obtained, and a first-order lag filter is performed to obtain the second signal. The first-order lag filter assigns different weights to the data from the previous time point and the data from the current time point to reduce the frequency of fluctuations.

[0079] S303 uses the first signal as the set value and the second signal as the measured value to perform difference calculation and proportional-integral-derivative adjustment calculation to obtain the first frequency conversion frequency.

[0080] Specifically, the first signal obtained from the second water purification device and the second signal obtained from the first water purification device are input to the PID controller (proportional integral derivative controller) for adjustment calculation. The first signal is used as the set value and the second signal is used as the measured value. That is, the outlet flow rate of the second water purification device is used as the reference to adjust the frequency of the inverter of the water pump of the water purification device to be adjusted, so that the outlet flow rates of the second water purification device and the first water purification device are basically consistent, so that the entire chemical water purification system achieves a dynamic water balance.

[0081] S304, Obtain the second frequency conversion frequency based on the water tank level of the water purification device to be adjusted;

[0082] S305, the third frequency is obtained based on the first and second frequency conversion frequencies;

[0083] S306, based on the inlet pressure value of the water purification device to be adjusted, the third frequency converter is limited and then output as the final frequency converter, or the third frequency converter is directly output as the final frequency converter.

[0084] S307, the final frequency of the variable frequency drive is input to the water pump of the water production device to be adjusted in order to control the water pump.

[0085] Figure 5 This is a flowchart of an automatic control method for a water purification device provided in another embodiment of the present invention, as shown below. Figure 4 , 5 As shown, the automatic control method includes:

[0086] S401, obtain the first outlet flow rate of all water-making devices in the second water-making equipment, obtain the second outlet flow rate of the water-making device to be adjusted, and obtain the first frequency conversion frequency based on the first and second outlet flow rates.

[0087] S402, Obtain the water tank level of the water purification device to be adjusted, and obtain the second frequency conversion frequency according to the preset function;

[0088] Specifically, the preset functions include the frequency function of the water pump inverter of the water production device to be adjusted, corresponding to the water level in the water tank of the first water production device.

[0089] The frequency of the second frequency converter depends on the water level in the tank of the first water treatment device. Therefore, based on the above steps ensuring that the outlet flow rates of the second and first water treatment devices are basically consistent to achieve dynamic water balance in chemical water treatment, the second frequency converter obtained in step S402 can ensure the stability of the water level in the tank.

[0090] S403, the third frequency is obtained based on the first and second frequency conversion frequencies;

[0091] S404, based on the inlet pressure value of the water purification device to be adjusted, the third frequency converter is limited and then output as the final frequency converter, or the third frequency converter is directly output as the final frequency converter.

[0092] S405, the final frequency of the variable frequency drive is input to the water pump of the water production device to be adjusted in order to control the water pump;

[0093] Figure 6 This is a flowchart of an automatic control method for a water purification device provided in another embodiment of the present invention, as shown below. Figure 4 , 6 As shown, the automatic control method includes:

[0094] S501, obtain the first outlet flow rate of all water-making devices in the second water-making equipment, obtain the second outlet flow rate of the water-making device to be adjusted, and obtain the first frequency conversion frequency based on the first and second outlet flow rates.

[0095] S502, obtain the water tank level of the water purification device to be adjusted, and obtain the second frequency conversion frequency according to the preset function;

[0096] S503, the first frequency converter frequency is added to the second frequency converter frequency to obtain the third frequency converter frequency;

[0097] Combining the above steps, for example, when establishing the preset function, a calibrated water level value for the first water treatment device is preset, and the preset function is the pump frequency conversion frequency corresponding to the difference between the current real-time water level and the calibrated water level value. If the current real-time water level is higher than the calibrated water level value, the pump frequency conversion frequency needs to be reduced to decrease the difference between the real-time water level and the calibrated water level. Therefore, the preset function includes a negative frequency conversion frequency corresponding to the current real-time water level. If the current real-time water level is lower than the calibrated water level value, the pump frequency conversion frequency needs to be increased to reduce the difference between the real-time water level and the calibrated water level. Therefore, the preset function includes a positive frequency conversion frequency corresponding to the current real-time water level. At this time, the second frequency can be regarded as a compensation for the first frequency conversion frequency. Therefore, in step S503, the first frequency conversion frequency and the second frequency conversion frequency are added together to adjust the value of the first frequency conversion frequency, thus obtaining the third frequency conversion frequency. When the real-time water level is higher than the calibrated water level, the third frequency converter frequency is lower than the first frequency converter frequency; when the real-time water level is lower than the calibrated water level, the third frequency converter frequency is higher than the first frequency converter frequency.

[0098] In this embodiment of the invention, the outlet flow rates of the water treatment device to be adjusted in the second water treatment equipment and the downstream water treatment equipment are similar, ensuring the dynamic water balance of chemical water treatment, while also ensuring the relative stability of the water level in the tank of the second water treatment equipment.

[0099] S504, based on the inlet pressure value of the water purification device to be adjusted, the third frequency converter is limited and then output as the final frequency converter, or the third frequency converter is directly output as the final frequency converter.

[0100] S505, the final frequency of the variable frequency drive is input to the water pump of the water production device to be adjusted in order to control the water pump.

[0101] Figure 7 This is a flowchart of an automatic control method for a water purification device provided in another embodiment of the present invention, as shown below. Figure 4 , 7 As shown, the automatic control method includes:

[0102] S601, obtain the first outlet flow rate of all water-making devices in the second water-making equipment, obtain the second outlet flow rate of the water-making device to be adjusted, and obtain the first frequency conversion frequency based on the first and second outlet flow rates.

[0103] S602, obtain the second frequency conversion frequency based on the water tank level of the water purification device to be adjusted;

[0104] S603, the third frequency is obtained based on the first frequency and the second frequency;

[0105] S604, acquire the inlet pressure signal of the water purification device to be adjusted; when the inlet pressure signal is not faulty, and when the inlet pressure is higher than the first preset threshold or lower than the second preset threshold, after a first preset time interval, limit the third frequency conversion frequency, and output the fourth frequency conversion frequency after the limit; the fourth frequency conversion frequency is the final frequency conversion frequency.

[0106] The water purification device in the first water purification equipment has working pressure requirements. Too high a pressure will damage the equipment or filter membrane, while too low a pressure will cause the equipment to not produce water or produce too little water.

[0107] For example, when the inlet pressure value of the water purification device to be adjusted is higher than a first preset threshold or lower than a second preset threshold, it indicates that the inlet pressure of the water purification device to be adjusted is too high or too low. Therefore, a first preset time interval is first delayed to prevent sudden large fluctuations in the analog input signal or interference from other signals, which could cause logical misjudgment. Optionally, the first preset time interval is 3 seconds. Afterwards, the third frequency converter is limited, restricting its highest or lowest value. Situations where signal quality is not compromised include: the measurement circuit is not disconnected, communication is not faulty, and the signal is not over-range.

[0108] Optional, such as Figure 4 As shown, after acquiring the inlet pressure signal of the water purification device to be adjusted, the first channel detects the inlet pressure value and outputs a first-level signal accordingly. The second channel detects whether the signal quality is poor and outputs a second-level signal accordingly. When the first channel detects that the inlet pressure value is higher than a first preset threshold or lower than a second preset threshold, the first-level signal is output as a low-level signal. When the second channel detects that the signal quality is good, the second-level signal is output as a high-level signal. The result of the AND operation between the first-level signal and the second-level signal is the third-level signal. When the third-level signal is low, the third frequency converter is limited.

[0109] S605, the final frequency of the variable frequency drive is input to the water pump of the water production device to be adjusted in order to control the water pump.

[0110] In an automatic control method for a water purification device provided in this invention, after obtaining the third frequency converter, the method determines whether the third frequency converter needs to be limited by detecting the inlet pressure value of the water purification device to be adjusted. When the inlet pressure value of the water purification device to be adjusted is higher than a first preset threshold or lower than a second preset threshold, the third frequency converter is limited before output to prevent the output frequency converter from being too high or too low, thus preventing insufficient system pressure or damage to the equipment.

[0111] Figure 8 This is a flowchart of an automatic control method for a water purification device provided in another embodiment of the present invention, as shown below. Figure 4 , 8 As shown, the automatic control method includes:

[0112] S701, obtain the first outlet flow rate of all water-making devices in the second water-making equipment, obtain the second outlet flow rate of the water-making device to be adjusted, and obtain the first frequency conversion frequency based on the first and second outlet flow rates.

[0113] S702, obtain the second frequency conversion frequency based on the water tank level of the water purification device to be adjusted;

[0114] S703, the third frequency is obtained based on the first frequency and the second frequency;

[0115] S704, acquire the inlet pressure signal of the water purification device to be adjusted; when the inlet pressure signal is not faulty, and the inlet pressure is less than the first preset threshold and greater than the second preset threshold, directly output the third frequency conversion frequency as the final frequency conversion frequency.

[0116] Specifically, the system acquires the inlet pressure signal of the water purification device to be adjusted. When the inlet pressure is less than the first preset threshold and greater than the second preset threshold, it directly outputs the third frequency converter as the final frequency converter. Signal quality is considered good under the following conditions: the measurement circuit is not disconnected, communication is not faulty, and the signal is not over-range.

[0117] Optional, such as Figure 4 As shown, after acquiring the inlet pressure signal of the water purification device to be adjusted, the first channel detects the inlet pressure value and outputs a first-level signal accordingly. The second channel detects whether the signal quality is poor and outputs a second-level signal accordingly. When the first channel detects that the inlet pressure value is less than a first preset threshold and greater than a second preset threshold, the first-level signal is output as a high-level signal. When the second channel detects that the signal quality is good, the second-level signal is output as a high-level signal. The result of the AND operation between the first-level signal and the second-level signal is the third-level signal. When the third-level signal is high, the third frequency converter is directly output as the fourth frequency converter.

[0118] S705, the final frequency of the variable frequency drive is input to the water pump of the water production device to be adjusted in order to control the water pump.

[0119] Continue to refer to Figure 4 In conjunction with the above, in the automatic control method of the water purification equipment provided in the embodiments of the present invention, the method switches to manual mode as needed to manually input the frequency of the water pump of the water purification device to be adjusted.

[0120] If parameter acquisition fails, switch to manual control mode.

[0121] Specifically, such as Figure 4 As shown, when acquiring the outlet flow rate of the water purification device in the second water purification device and the first water purification device, if the acquired signal quality is poor, the system switches to manual control mode; when acquiring the frequency feedback signal of the water pump inverter of the water purification device to be adjusted, if the acquired signal quality is poor, the system switches to manual control mode; wherein, the acquired signal quality poor includes: measurement circuit disconnection, communication failure and signal over-range.

[0122] When the deviation between the set value and the measured value is greater than the third preset threshold, switch to manual control mode.

[0123] Specifically, such as Figure 4 As shown, after acquiring the setpoint and measured value, when the difference between the setpoint and measured value exceeds a third preset threshold, the system switches to manual control mode. The first signal obtained from the second water purification device and the second signal obtained from the first water purification device are input to the PID controller (proportional-integral-derivative controller) for adjustment calculations; that is, the first signal is used as the setpoint and the second signal is used as the measured value. When the deviation between the first and second signals is too large, the outlet flow rates of the first and second water purification devices become abnormal, or an anomaly occurs during data acquisition. In this case, the data is not valuable for adjustment calculations, therefore the system switches to manual control mode.

[0124] When the difference between the final frequency command given to the variable frequency drive and the frequency feedback signal of the water pump inverter of the water treatment device to be adjusted exceeds the fourth preset threshold, the system switches to manual control mode.

[0125] Specifically, such as Figure 4 As shown, after the water pump of the water treatment device to be adjusted receives the final frequency conversion command, it acquires the frequency feedback signal from the frequency converter of the first water treatment device's pump. When the difference between the frequency feedback signal and the final frequency conversion command exceeds a fourth preset threshold, it switches to manual control mode. When the difference between the frequency feedback signal and the final frequency conversion is large, it indicates that the water pump has not fully executed the frequency conversion command after the final frequency conversion is input to the frequency converter of the water pump of the water treatment device to be adjusted; therefore, it is necessary to switch to manual control mode.

[0126] The manual control mode includes manually inputting the frequency of the water pump of the water purification device to be adjusted.

[0127] For example, such as Figure 4 As shown, after switching to manual mode, a certain amount of offset is manually input to adjust the pump frequency of the water purification device to be adjusted.

[0128] This invention provides an automatic control method for water purification equipment. When parameter acquisition fails, the setpoint and measured values ​​deviate significantly, or the final frequency command given to the inverter deviates significantly from the frequency feedback signal of the water pump inverter in the water purification device to be adjusted, the method switches to manual control mode. This automatic control method not only automatically adjusts the water purification system to achieve dynamic water balance, but also monitors its operation. When an abnormality occurs, it switches to manual control mode, thus achieving stability and fault tolerance in the automatic control method for water purification equipment.

[0129] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An automatic control method for a water purification device, characterized in that, The water production equipment includes a first water production device and a second water production device; the first water production device includes a two-stage reverse osmosis device, and the second water production device includes an electro-deionization device; or, the first water production device includes a first-stage reverse osmosis device, and the second water production device includes a two-stage reverse osmosis device or an electro-deionization device; or, the first water production device includes an ultrafiltration device, and the second water production device includes a first-stage reverse osmosis device, a two-stage reverse osmosis device, or an electro-deionization device; the first water production device and the second water production device each include a water tank and at least one water production device, and each water production device corresponds to at least one water pump; The automatic control method includes: The sum of the real-time flow rates at the outlets of all water purification devices in the second water purification equipment is obtained and divided by the number of water purification devices in the first water purification equipment. The calculation result is rate-limited to obtain a first signal quantity. The real-time flow rate at the outlet of the water purification device to be adjusted is obtained and first-order hysteresis filtering is performed to obtain a second signal quantity. The first signal quantity is used as a set value and the second signal quantity is used as a measured value. The difference is calculated and proportional-integral-derivative adjustment is performed to obtain a first frequency conversion. The water purification device to be adjusted is the water purification device in the first water purification equipment whose pump frequency conversion is to be adjusted. The water tank level of the water production device to be adjusted is obtained, and the second frequency conversion frequency is obtained according to a preset function; the preset function includes the frequency function of the water pump frequency converter of the water production device to be adjusted corresponding to the water tank level of the first water production device. The first frequency conversion frequency is added to the second frequency conversion frequency to obtain the third frequency conversion frequency; Acquire the inlet pressure signal of the water purification device to be adjusted. When the inlet pressure signal is of good quality, and when the inlet pressure value is higher than a first preset threshold or lower than a second preset threshold, after a first preset time interval, limit the third frequency conversion frequency, and then output the fourth frequency conversion frequency; the fourth frequency conversion frequency is the final frequency conversion frequency; or... The inlet pressure signal of the water purification device to be adjusted is obtained. When the inlet pressure signal is not damaged, and the inlet pressure is less than the first preset threshold and greater than the second preset threshold, the third frequency conversion frequency is directly output as the final frequency conversion frequency. The signal quality is not compromised, including: the measurement circuit is not disconnected, communication is not faulty, and the signal is not out of range; The final frequency of the variable frequency drive is input to the water pump of the water production device to be adjusted in order to control the water pump.

2. The automatic control method for the water purification equipment according to claim 1, characterized in that, Also includes: If parameter acquisition fails, switch to manual control mode; When the deviation between the set value and the measured value is greater than the third preset threshold, switch to manual control mode; When the difference between the final frequency conversion command and the frequency feedback signal of the water pump frequency converter of the water treatment device to be adjusted exceeds the fourth preset threshold, switch to manual control mode. The manual control mode includes manually inputting the frequency of the water pump of the water treatment device to be adjusted.

3. The automatic control method for the water purification equipment according to claim 2, characterized in that, If the parameter acquisition fails, switch to manual control mode, including: when acquiring the outlet flow rate of the water production device in the second water production device and the first water production device, if the acquired signal is of poor quality, switch to manual control mode. When obtaining the frequency feedback signal of the water pump inverter of the water treatment device to be adjusted, if the obtained signal is of poor quality, switch to manual control mode. The acquired signal quality defects include: measurement circuit disconnection, communication failure, and signal over-range.

4. The automatic control method for the water purification equipment according to claim 2, characterized in that, When the deviation between the set value and the measured value is greater than a third preset threshold, the system switches to manual control mode, including: After obtaining the set value and the measured value, when the difference between the set value and the measured value is greater than the third preset threshold, switch to manual control mode.

5. The automatic control method for the water purification equipment according to claim 2, characterized in that, When the difference between the final frequency conversion command and the frequency feedback signal of the water pump frequency converter of the water treatment device to be adjusted exceeds the fourth preset threshold, the system switches to manual control mode, including: After the water pump of the water production device to be adjusted obtains the final frequency conversion command, the frequency feedback signal of the frequency converter of the first water production device is obtained. When the difference between the frequency feedback signal and the final frequency conversion command exceeds the fourth preset threshold, the system switches to manual control mode.

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