Water level identification method, control method and system based on motor current

Abstract

The invention discloses a motor current-based water level identification method, control method and system, and the method comprises the following steps: a motor operates, and carries out the real-time current sampling according to a preset sampling rate; when the motor operation time reaches the preset motor detection time, obtaining a current sampling data set; actual water level data are calculated according to the current sampling data set and the preset corresponding relation between the motor current and the water level. The method has the advantages that additional hardware is not needed, the manufacturing cost is reduced, the damage risk is reduced, the life cycle of household appliances is prolonged, and meanwhile the accuracy of water level detection is ensured.

Description

Technical Field

[0001] The present application relates to the technical field of water level identification of household appliances, and in particular to a water level identification method, control method and system based on motor current. Background Art

[0002] Many household appliances, such as washing machines and dishwashers, need to be cleaned with water, which determines that there are water inlet units and drainage units. Too much or too little water during cleaning will cause corresponding problems. In order to achieve precise control of the amount of water in the machine, the water level must be detected. However, the current technical solution needs to be equipped with sensors for detection, not to mention that it will increase the cost of the whole machine. After adding hardware sensors, the sensors have their service life under complex and different working conditions, and the wiring harness connectors of the sensors will also have the risk of aging and poor contact, which simultaneously increases the risk of damage to household appliances. Once damaged, users can only repair them, which is quite inconvenient and reduces the user experience. After adding sensors, the main control MCU also needs to occupy the internal resources of the relevant chips (such as IIC, SPI, UART, IO ports, etc.) to communicate with them, which also increases the hardware cost.

[0003] The Chinese patent "Hall Element Water Level Detection Circuit, System, Equipment and Water Tank", publication number: CN 219474734 U, publication date: August 4, 2023, specifically discloses that a method of using an AD sampling voltage to determine the water level is used to replace the IO port level detection scheme, and multiple Hall elements are used to detect multiple water levels. Only a small number of IO ports are needed for voltage detection, which reduces the cost of IC selection and the number of IO ports. However, this solution still uses multiple Hall elements for water level detection, which increases the cost of the entire device and adds too many sensors, resulting in an increase in the number of components that may fail in the device, and the life cycle will also be affected by the sensor life cycle and reduced.

[0004] The Chinese patent "A method for realizing water level detection based on image inverse perspective transformation", publication number: CN115908370A, publication date: April 4, 2023, specifically discloses: S1: Detect the water level gauge to obtain the overall target area of ​​the water level gauge and the water level gauge scale target area; at the same time, segment the water surface to obtain the water surface segmentation result; S2: Make inclination judgment based on the water level gauge scale detection frame and the water level gauge detection frame, and calculate the pixel distance; S3: Use the pixel distance between the top of the water level gauge detection frame and the water level line, combined with the real distance represented by the pixel to calculate the real height of the water level gauge. This scheme uses inverse perspective transformation to realize the tilt correction of the water level gauge in the image, and obtains the position of the water level line by intersecting the water level gauge with the water surface segmentation result, so as to obtain the accurate water level value. It requires additional shooting devices, which also increases the cost of the entire device. The possibility of failure of the shooting device is increased, resulting in an increase in the maintenance cost of the entire device, and the life cycle will also be affected by the life cycle of the sensor and reduced. Summary of the invention

[0005] In order to solve the problem in the prior art that water level detection of household appliances requires the use of additional sensors, which makes the hardware structure of the household appliances complicated and may lead to an increased failure rate, the present application provides a water level recognition method, a control method and a system based on motor current. The motor that must exist in household appliances that require water cleaning is used to establish a relationship between the motor current and the water level based on the relationship between the motor current and the load, and the relationship between the load and the water level. The real-time motor current is collected to calculate the motor current under the current load, and the actual water level data is obtained based on the relationship between the motor current and the water level to achieve water level recognition. The actual water level data is compared with the required water level to determine whether the required water level is met to achieve water level control. The hardware that must exist in household appliances that require water cleaning is reused without adding additional hardware, thereby slimming down the overall hardware structure of the household appliances. While ensuring the accuracy of water level detection, the manufacturing cost and the risk of damage to the household appliances are reduced, thereby extending the life cycle of the household appliances.

[0006] In order to achieve the above-mentioned technical objectives, a technical solution provided by the present application is a water level identification method based on motor current, including the following steps: S1: the motor is running, and real-time current sampling is performed according to a preset sampling rate; S2: when the motor running time reaches the preset motor detection time, a current sampling data set is obtained; S3: the actual water level data is calculated based on the current sampling data set and the preset correspondence between the motor current and the water level.

[0007] Furthermore, the S3 also includes: S31: presetting a cutoff frequency, and filtering the current sampling data set according to the cutoff frequency; S32: presetting a sampling rate, sampling the current sampling data set, and obtaining a sampling set; S33: calculating the actual water level data according to the sampling set and the corresponding relationship between the motor current and the water level.

[0008] Furthermore, a preset correspondence between the motor current and the water level is obtained based on the historical motor current data and the water level data.

[0009] Furthermore, the S3 also includes: calculating a current average value according to the current sampling data set, obtaining a current interval in which the current average value is located, and outputting an actual water level interval according to a preset corresponding relationship between the current interval and the water level interval.

[0010] Furthermore, the real-time current sampling according to the preset sampling rate includes: S11: performing real-time current sampling according to the preset sampling rate to obtain the sampled current; S12: dividing the cycle according to the preset sampling number, using Kirchhoff's law to reconstruct the sampled current included in each cycle, and performing current coordinate transformation to obtain the motor current in each cycle.

[0011] Another technical solution provided by the present application is a water level control method based on motor current, which realizes water level control by using the water level identification method based on motor current as mentioned above, and includes the following steps: S01: obtaining required water level data, executing the water level change program, timing, and obtaining the water level change time; S02: when the water level change time reaches the preset water level detection time, controlling the motor to run at the detection speed; S03: executing S1-S3 to obtain actual water level data; S04: determining whether the actual water level data meets the required water level data, if so, ending the water level change program, if not, re-executing S01-S04.

[0012] Furthermore, the S01 also includes: acquiring required water level data, and selecting a preset water level detection time according to the required water level data.

[0013] Furthermore, the S04 also includes: determining whether the actual water level data meets the required water level data, if so, terminating the water level change program, if not, obtaining the difference between the required water level data and the actual water level data, determining the water level at which the difference is located, updating the preset water level detection time, and re-executing S01-S04.

[0014] Another technical solution provided by the present application is a water level identification system based on motor current, which is used to implement the water level identification method as mentioned above, including: a current data acquisition module, which is used to perform real-time sampling of the motor current to obtain a current sampling data set; a water level judgment module, which is used to pre-store the correspondence between the motor current and the water level, and perform water level identification according to the current sampling data set.

[0015] Another technical solution provided by the present application is a water level control system based on motor current, which is used to implement the above-mentioned water level control method, including: a motor MCU, which is used to drive the motor to run according to control instructions, and to sample the motor current in real time to obtain a current sampling data set; a main control MCU, which is used to output control instructions to the motor MCU according to the current program running status, and obtain the current sampling data set to perform water level judgment, and control the opening and closing of the water inlet and outlet device according to the water level judgment result.

[0016] The beneficial effects of the present application are as follows: the hardware that must exist in household appliances that require water cleaning can be reused without adding additional hardware, thereby reducing manufacturing costs, reducing the risk of damage, extending the life cycle of household appliances, and ensuring the accuracy of water level detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of an embodiment of a water level identification method based on motor current of the present application.

[0018] Figure 2 This is a flow chart of an embodiment of a water level control method based on motor current of the present application.

[0019] Figure 3 This is a control schematic diagram of an embodiment of the water level control method based on motor current of the present application.

[0020] Figure 4 This is a schematic diagram of the structure of an embodiment of a water level control system based on motor current in the present application. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below in conjunction with the drawings and examples. It should be understood that the specific implementation method described here is only an optimal embodiment of the present application, which is only used to explain the present application and does not limit the scope of protection of the present application. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0022] like Figure 1 As shown, as the first embodiment of the first aspect of the present application, the water level identification method based on motor current includes the following steps: S1: The motor is running and real-time current sampling is performed according to the preset sampling rate; S2: When the motor running time reaches the preset motor detection time, a current sampling data set is obtained; S3: Calculate the actual water level data based on the current sampling data set and the preset correspondence between the motor current and the water level.

[0023] In this embodiment, the preset motor current and water level correspondence is obtained based on the historical motor current data and water level data. In household appliances that require water cleaning, such as washing machines and dishwashers, a motor is required to drive the mechanical structure to move. For example, in a washing machine, the motor needs to drive the belt, pull the clutch, and rotate the impeller. When the water level in the household appliance changes, the load also changes, and the motor current also changes accordingly.

[0024] According to the basic principles of electromechanics, the electromagnetic torque of the motor can be obtained by calculating the quadrature axis component of the stator current and the permanent magnet flux: Among them, T e is the electromagnetic torque of the motor, I q is the quadrature axis component of the motor stator current, N p is the number of motor pole pairs, φ is the permanent magnet flux.

[0025] According to the basic principles of electromechanics, the electromagnetic torque of the motor can also be obtained through the motor's moment of inertia and the motor's load torque: Among them, T e is the electromagnetic torque of the motor, J is the moment of inertia of the motor, n is the mechanical speed of the motor, t is the rotation time of the motor, T L is the load torque.

[0026] Calculate the load torque using the load variable and the motor mechanical speed: T L =Kn 2 ; Where K is the load variable related to the water level. When the water level changes, the load variable also changes accordingly.

[0027] In an AC motor, the stator current can be decomposed into a direct-axis component and a quadrature-axis component, thus: Among them, I s is the motor current, I d is the direct axis component of the motor stator current.

[0028] Under normal circumstances, the number of motor pole pairs and permanent magnet flux remain unchanged during motor operation. After the motor starts, the speed rises to a fixed speed and then remains stable. At this time, the motor mechanical speed is constant. In a hidden pole motor, the direct axis component of the motor stator current has no direct relationship with the motor electromagnetic torque, making I d =0, the torque current is maximum, that is, I s =I qAccording to the above relationship, the load variable is directly proportional to the electromagnetic torque of the motor, and the electromagnetic torque of the motor is directly proportional to the quadrature-axis component of the stator current. Thus, the corresponding relationship between the load variable and the motor current can be obtained.

[0029] In this embodiment, historical motor current data and water level data are obtained, and a mathematical model of water level and motor current is constructed to reflect the correspondence between motor current and water level. The relationship between water level and load variable can be obtained based on the historical motor current data and water level data, thereby converting the correspondence between load variable and motor current into the correspondence between water level and motor current, that is, the correspondence between water level and motor current.

[0030] After the corresponding relationship between the water level and the motor current is calculated, it is stored in the main control side of the system. When the system calls water level recognition, the motor runs, and real-time current sampling is performed according to the preset sampling frequency to obtain a current sampling data set, and according to the corresponding relationship between the water level and the motor current, the current actual water level data is obtained, thereby realizing the recognition of the current water level. It can be understood that in some embodiments, the water level recognition can be always in the starting state, that is, when the machine is turned on, the water level recognition is started, so as to continuously output the actual water level data and realize real-time monitoring of the water level. In other embodiments, the recognition time can also be set, and the water level recognition is started when the preset recognition time is reached.

[0031] In this embodiment, a correspondence between the motor current and the water level is established through the motor that must exist in household appliances that require water cleaning. When the motor is running, the load is judged by the actual motor current, and the water level is judged by the load. This eliminates the need for additional water level detection sensors, reduces manufacturing costs, reduces the risk of damage, and extends the life cycle of household appliances.

[0032] As a second embodiment of this aspect, performing real-time current sampling according to a preset sampling rate includes: S11: Perform real-time current sampling according to a preset sampling rate to obtain a sampled current; S12: Divide the cycle according to the preset sampling times, reconstruct the sampled current included in each cycle using Kirchhoff's law, and perform current coordinate transformation to obtain the motor current in each cycle.

[0033] At this time, the current sampling data set is: The motor current set within the preset motor detection time.

[0034] In this embodiment, the preset sampling times is two, and the corresponding sampling current obtained in one cycle is I a ,I b According to Kirchhoff's law, the sampled current is reconstructed to obtain the corresponding three-phase current I a ,Ib ,I c According to Kirchhoff's current law, for each node, the sum of the currents flowing into the node is equal to the sum of the currents flowing out of the node. Therefore, according to the three-phase current characteristics, I a +I b +I c =0, at this time, the sampling current I a ,I b , can be reconstructed to obtain I c .

[0035] The execution of the current coordinate change includes: executing CLARKE transformation and PARK transformation on the current coordinate. CLARKE transformation (Clark transformation) transforms the current coordinate from a three-phase stationary coordinate system to a two-phase stationary coordinate system, and PARK transformation (Park transformation) transforms the three-phase current I a ,I b ,I c Projected onto the direct axis (d axis) rotating with the rotor, the quadrature axis (q axis) and the zero axis (0 axis) perpendicular to the dq plane, thus achieving the diagonalization of the stator inductance matrix. a ,I b ,I c After the CLARKE transformation, it is converted into a variable based on the dq coordinate system, and then the variable based on the dq coordinate system is converted into I in the rotating coordinate system through the PARK transformation. q and I d , and according to I s =I q Get the motor current I s .

[0036] In this embodiment, step 3 of calculating the actual water level data according to the current sampling data set and the preset correspondence between the motor current and the water level also includes: S31: Preset a cutoff frequency, and filter the current sampling data set according to the cutoff frequency; S32: preset a sampling rate, sample the current sampling data set, and obtain a sampling set; S33: Calculate the actual water level data based on the sampling set and the corresponding relationship between the motor current and the water level.

[0037] The current sampling data set, i.e. the motor current set, is filtered by the cutoff frequency to remove the interference data in the sampled data and improve the accuracy of the final result judgment. The filtered motor current is sampled to reduce the amount of calculation while avoiding excessive redundant information affecting the analysis results, further improving the efficiency and accuracy of data analysis and reducing the pressure of data storage and processing.

[0038] As a third embodiment of the present aspect, the correspondence between the motor current and the water level is obtained based on the historical motor current data and the water level data, and the correspondence between the current interval and the water level interval is established.

[0039] Step S3 includes: The current average value is calculated according to the current sampling data set, the current interval in which the current average value is located is obtained, and the actual water level interval is output according to the preset corresponding relationship between the current interval and the water level interval.

[0040] In this embodiment, the correspondence between the motor current and the water level is converted into the relationship between the current interval and the water level interval as shown in Table 1. When performing the actual water level calculation, the current average value is calculated to determine which current interval the current is in, and the corresponding actual water level interval is obtained, thereby avoiding the problem of the current sampling error caused by the loop causing the actual judgment result to be wrong.

[0041] Table 1. Correspondence between current range and water level range Serial number Current range Water level range 1 ～A Water level interval 1 2 A~B Water level interval 2 3 B~C Water level interval 3 … … … N F～ Water level interval N and above

[0042] In order to enhance the robustness of the system, step S5 further includes: The current data of the preset time period in the current sampling data set is obtained, and the current average value is calculated to obtain the current interval in which the current average value is located. According to the corresponding relationship between the preset current interval and the water level interval, the actual water level interval is output.

[0043] like Figure 2 , Figure 3 As shown, as an embodiment 1 of the second aspect of the present application, a water level control method based on motor current, using the water level identification method based on motor current as described above to realize water level control, includes the following steps: S01: Obtain the required water level data, execute the water level change program, perform timing, and obtain the water level change time; S02: When the water level change time reaches the preset water level detection time, the motor is controlled to run at the detection speed; S03: Execute S1-S3 to obtain actual water level data; S04: Determine whether the actual water level data meets the required water level data. If so, end the water level change program. If not, re-execute S01-S04.

[0044] In water level control, since the water level of machines such as household appliances is 0 in the initial state, the water inlet or outlet is first controlled according to the required water level data. After reaching the preset water level detection time, the motor is controlled to run at the detection speed and water level identification is performed to obtain the actual water level data and determine whether the actual water level data meets the required water level. If so, the water level change program is terminated. If not, the water level change program continues to be executed to allow water in or out and perform water level identification until the required water level is reached and the water level change program is terminated.

[0045] As embodiment 2 corresponding to embodiment 1 of the first aspect, S01 further includes: Obtain the required water level data and select the preset water level detection time according to the required water level data.

[0046] Therefore, according to different required water levels, water intake or drainage is performed at different times to meet the water intake or drainage time of different required water levels.

[0047] S04 also includes: Determine whether the actual water level data meets the required water level data. If so, end the water level change program. If not, obtain the difference between the required water level data and the actual water level data, determine the water level at which the difference is located, update the preset water level detection time, and re-execute S01-S04.

[0048] At this time, according to the relationship between the water level, water flow speed and time, the water inflow or drainage time to reach the preset water level is established as the preset water level detection time, and each preset water level corresponds to a preset water level detection time. When the water inflow or drainage does not meet the required water level, the water inflow or drainage has actually been carried out for a part of the time. If the water inflow or drainage time is set according to the required water level, it will cause too much water inflow or too much drainage. Therefore, the water level change of the next water inflow is judged according to the difference between the required water level and the actual water level, and the preset water level detection time is updated with the preset water level corresponding to the water level where the difference is located, so as to realize the setting of drainage or water inflow time according to the actual required water level change, and ensure the accuracy of the water level change time.

[0049] As embodiment 3 corresponding to embodiment 3 of the first aspect, step S01 further includes: Get the required water level range and select the preset water level detection time according to the required water level range.

[0050] Therefore, according to different demand water level intervals, water intake or drainage at different times is performed to meet the water intake or drainage time in different demand water level intervals.

[0051] In other embodiments, step S04 further includes: Determine whether the actual water level interval meets the required water level interval. If so, end the water level change program. If not, obtain the difference between the required water level interval and the actual water level interval, determine the water level interval in which the difference lies, update the preset water level detection time, and re-execute S01-S04.

[0052] At this time, each water level interval corresponds to a preset water level detection time. When the water inflow or drainage does not meet the required water level, the water level change interval for the next water inflow is determined based on the difference between the required water level interval and the actual water level interval, and the preset water level detection time is updated with the water level interval where the difference is located, so as to set the drainage or water inflow time according to the actual required water level change and ensure the accuracy of the water level change time.

[0053] It is understandable that the water level change program mentioned in the present application includes a series of programs that will cause water level changes, such as water inlet and water outlet. When the machine is turned on, it runs according to the corresponding program, such as washing according to the laundry program in a washing machine. When the program runs to the water level change program, the main control side controls the water inlet valve or the drain valve of the machine to open, and performs timing, and pre-sets the predicted water level detection time. When the main control side timing reaches the predicted water level detection time, the motor is controlled to run at the detection speed for the preset motor detection time, and when the motor runs at the detection speed, the motor current is sampled in real time at a preset sampling rate to obtain a current sampling data set, and according to the corresponding relationship between the water level and the motor current, the current actual water level data is obtained. According to the required water level set by the water level change program, it is judged whether the actual water level data needs to meet the required water level. If so, the next step is executed. If not, the water level change program is repeatedly executed, and the actual water level data is recalculated until the actual water level meets the required water level.

[0054] As a fourth embodiment of the present invention, 2000rpm (Revolution Per Minute) is used as the detection speed, 10s is used as the preset motor detection time, 10K SPS (Sample Per Second) is used as the preset sampling rate, 2 times is used as the preset sampling number, 10 Hz is used as the preset cutoff frequency, 5 Hz is used as the preset sampling rate, 7s is used as the preset water level detection time, 1000rpm / s is used as the acceleration of the motor speed-up, and the last 3s is used as the preset time period. The water level recognition method based on the motor current is: After the machine is turned on, the corresponding program is selected to run. When the sequence runs to the water level change program, the drain pump or the water inlet valve is opened; after 7 seconds, the motor increases to the target speed of 2000rpm at an acceleration of 1000rpm / s and maintains operation. During this period, real-time current sampling is performed at 10KSPS, and the corresponding sampling currents Ia and Ib are obtained within one cycle; after 10 seconds, the motor returns to the operating speed without water level detection, and the motor current is calculated based on the sampled current; the motor current is filtered with a 10 Hz low-pass filter to obtain a filtered motor current set; the filtered motor current set is sampled at a sampling rate of 5 Hz to obtain 50 sampling data; the current data of the last 3s of the 50 sampling data are filtered, and averaged to obtain the final current average value; it is determined which preset interval value the current average value is within, and each current interval value here corresponds to an actual water level interval value; the required actual water level interval value is obtained based on the corresponding relationship between the two.

[0055] Take a washing machine as an example: When the main control side is currently in the water inlet stage, the required water level interval is set according to the optimal water level interval value of the washing sequence. If the actual water level interval obtained according to steps S1-S3 is smaller than the required water level interval, the water inlet valve is opened to let water in for 7 seconds and then steps S1-S3 are executed again until the actual water level interval is greater than or equal to the required water level interval. Then the water inlet stage ends and the washing stage is carried out.

[0056] When the main control side is currently in the drainage stage, the required water level interval is set according to the optimal water level interval value of the drainage sequence. If the actual water level interval obtained according to steps S1-S3 is greater than the required water level interval, the drainage pump is turned on to drain for 7 seconds and then steps S1-S3 are executed again until the actual water level interval is less than or equal to the required water level interval. After that, the drainage stage ends and the next sequence is executed.

[0057] As a third aspect of the present application, a water level identification system based on motor current is used to implement a water level identification method, including: A current data acquisition module is used to sample the motor current in real time to obtain a current sampling data set; The water level judgment module is used to pre-store the corresponding relationship between the motor current and the water level, and perform water level identification according to the current sampling data set.

[0058] Among them, the current data acquisition module and the water level judgment module are communicated and connected, so that when the current data acquisition module acquires the current sampling data set, it is transmitted to the water level judgment module, and the water level judgment module performs the calculation of the actual water level data to realize water level identification.

[0059] In some embodiments, the water level determination module always collects the current generated when the motor is running, and transmits it to the water level determination module in real time, and the water level determination module outputs the current water level data in real time. In other embodiments, the water level determination module intermittently collects the current generated when the motor is running, and transmits it to the water level determination module in real time, so that the water level determination module also intermittently outputs the current water level data.

[0060] like Figure 4 As shown, as a fourth aspect of the present application, a water level control system based on motor current is used to implement a water level control method, including: The motor MCU is used to drive the motor to operate according to the control instructions and to sample the motor current in real time to obtain a current sampling data set; The main control MCU is used to output control instructions to the motor MCU according to the current program running status, obtain the current sampling data set to perform water level judgment, and control the opening and closing of the water inlet and outlet devices according to the water level judgment results.

[0061] At this time, the main control MCU is the main control side mentioned in the water level control method. The motor MCU is connected to the main control MCU in communication. The main control MCU obtains the current program running time. When running to the water level change program, the main control MCU outputs control instructions to the motor MCU according to the preset water level detection time, thereby controlling the motor to run at the detection speed. The motor MCU samples the motor current in real time to obtain a current sampling data set and outputs it to the main control MCU. The main control MCU calculates the actual water level data and determines whether the actual water level data meets the required water level data. If so, the water level change program ends and the next program is executed. If not, the main control MCU controls the opening and closing of the water inlet and outlet device according to the water inlet and outlet requirements, performs water inlet and outlet, and repeats the water level identification step. It can be understood that the water inlet and outlet device here refers to a device that realizes water inlet and outlet energy supply in household appliances, such as a water inlet valve, a drainage pump, etc.

[0062] Specifically, the motor MCU includes at least a motor drive module and a current data acquisition module, and the main control MCU includes at least a water level judgment module. The motor drive module is used to drive the motor to run according to the control instruction, the current data acquisition module is used to perform real-time sampling to obtain a current sampling data set, and the water level judgment module is used to obtain the current sampling data set to perform water level judgment.

[0063] In the present application, the preset correspondence between the motor current and the water level or the preset correspondence between the current interval and the water level interval can be pre-stored in the water level determination module.

[0064] In some other embodiments, the motor MCU further includes: A data transmission module, used to output the current sampling data set to the main control MCU; The data processing module is used to pre-process the current sampling data set.

[0065] The main control MCU sends a water level detection command to the motor MCU. After receiving the command, the motor MCU drives the motor to detect the speed. The current data acquisition module performs real-time sampling to obtain a current sampling data set. The data processing module performs low-pass filtering on the current sampling data set. According to the fluctuation of the water level data of the actual household appliance products, different cutoff frequencies are selected to eliminate hardware interference such as current glitches, so that the accuracy and stability of water level recognition are improved. The data transmission module transmits the current data and real-time speed after low-pass filtering, and communicates to the main control MCU through UART (Universal Asynchronous Receiver / Transmitter). Since the sampling rate of the motor current is generally high, this will result in a large amount of data to be transmitted after sampling. In order to increase the hardware anti-interference ability, the UART transmission rate between the main control MCU and the motor MCU usually selects a lower UART transmission rate. In order to balance the contradiction between the large amount of data and the lower transmission rate, the method of sampling the data is used to solve it: by sampling the current data, the amount of data to be transmitted can be reduced, and then the smaller amount of data can be transmitted at the current UART transmission rate. The water level judgment module receives the current data after sampling and filtering, calculates the actual water level and judges whether the actual water level meets the required water level, and decides on the control of the water volume according to the judgment result. It can be understood that in this application, the main control MCU is reused, that is, the main control MCU originally existing in the home appliance is used. Therefore, the functions originally existing in the main control MCU in the home appliance are not repeated in this application, such as controlling the opening and closing of the water inlet and outlet devices, timing control, program recognition, etc. The present application can be applied to a three-phase BLDC (Brushless Direct Current) motor system based on FOC (Field-Oriented Control) control. The system has a current sensor required for FOC control. At this time, the current sensor can be reused as a current data acquisition module.

[0066] In other embodiments, when the main control MCU determines that the preset water level detection time is reached, the water level change program is controlled to stop, that is, the drainage pump or the water inlet valve is controlled to stop working, until the water level judgment module determines that the required water level has not been reached, and the water level change program is re-executed. When the water level judgment module determines that the required water level has been reached, the next program is executed.

[0067] As a fifth aspect of the present application, a computer-readable storage medium is used to store a computer program or instruction. When the computer program or instruction is executed by a processing device, the above-mentioned water level identification method and water level control method are implemented. The computer-readable storage medium can be any available medium that can be stored by a computing device or a data storage device such as a data center containing one or more available media. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid-state hard disk), etc.

[0068] The specific implementation described above is a preferred implementation of the water level identification method, control method and system based on motor current of the present application, and is not intended to limit the specific implementation scope of the present application. The scope of the present application includes but is not limited to the specific implementation embodiment. All equivalent changes made in accordance with the shape and structure of the present application are within the protection scope of the present application.

Claims

1. A water level identification method based on motor current, characterized in that: The steps include: S1: The motor is running and real-time current sampling is performed according to the preset sampling rate; S2: When the motor running time reaches the preset motor detection time, a current sampling data set is obtained; S3: Calculate the actual water level data based on the current sampling data set and the preset correspondence between the motor current and the water level.

2. The water level identification method based on motor current according to claim 1, characterized in that: The S3 further includes: S31: Preset a cutoff frequency, and filter the current sampling data set according to the cutoff frequency; S32: preset a sampling rate, sample the current sampling data set, and obtain a sampling set; S33: Calculate the actual water level data based on the sampling set and the corresponding relationship between the motor current and the water level.

3. The water level identification method based on motor current according to claim 1, characterized in that: The preset motor current and water level correspondence is obtained based on the historical motor current data and water level data.

4. The water level identification method based on motor current according to claim 1, characterized in that: The S3 further includes: The current average value is calculated according to the current sampling data set, the current interval in which the current average value is located is obtained, and the actual water level interval is output according to the preset corresponding relationship between the current interval and the water level interval.

5. The water level identification method based on motor current according to claim 1, characterized in that: The performing real-time current sampling according to the preset sampling rate comprises: S11: Perform real-time current sampling according to a preset sampling rate to obtain a sampled current; S12: Divide the cycle according to the preset sampling times, reconstruct the sampled current included in each cycle using Kirchhoff's law, and perform current coordinate transformation to obtain the motor current in each cycle.

6. A water level control method based on motor current, wherein the water level control is realized by using the water level identification method based on motor current as claimed in any one of claims 1 to 5, characterized in that: The steps include: S01: Obtain the required water level data, execute the water level change program, perform timing, and obtain the water level change time; S02: When the water level change time reaches the preset water level detection time, the motor is controlled to run at the detection speed; S03: Execute S1-S3 to obtain actual water level data; S04: Determine whether the actual water level data meets the required water level data. If so, end the water level change program. If not, re-execute S01-S04.

7. The water level control method based on motor current according to claim 6, characterized in that: The S01 further includes: Obtain the required water level data and select the preset water level detection time according to the required water level data.

8. The water level control method based on motor current according to claim 7, characterized in that: The S04 further includes: Determine whether the actual water level data meets the required water level data. If so, end the water level change program. If not, obtain the difference between the required water level data and the actual water level data, determine the water level at which the difference is located, update the preset water level detection time, and re-execute S01-S04.

9. A water level recognition system based on motor current, used to implement the water level recognition method according to any one of claims 1 to 5, characterized in that: include: A current data acquisition module is used to sample the motor current in real time to obtain a current sampling data set; The water level judgment module is used to pre-store the corresponding relationship between the motor current and the water level, and perform water level identification according to the current sampling data set.

10. A water level control system based on motor current, used to implement the water level control method according to any one of claims 6 to 8, characterized in that: include: The motor MCU is used to drive the motor to run according to the control instructions and to sample the motor current in real time to obtain a current sampling data set; The main control MCU is used to output control instructions to the motor MCU according to the current program running status, obtain the current sampling data set to perform water level judgment, and control the opening and closing of the water inlet and outlet devices according to the water level judgment results.

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