Motor protection control method and system of snow melting machine

Abstract

The invention discloses a motor protection control method and system for a snow melting machine. The method comprises the following steps: calculating a change rate of current relative to a rotating speed based on a current difference value and a speed difference value; judging whether the change rate of the current relative to the rotating speed is within a preset change rate range or not, and executing an exception handling mode; whether the speed difference value is larger than a first preset threshold value or not is judged, and the abnormal state value is changed according to a judgment result; and judging whether the abnormal state value is greater than a second preset threshold value or not, and executing an abnormal adjustment mode. The system comprises a data acquisition module, a change rate calculation module, a first rotation blockage judgment module, a second rotation blockage judgment module, an abnormal state judgment module, an abnormality processing module, an abnormality adjustment module and an alarm module. According to the invention, the rotation blocking condition of the motor can be accurately detected, and the protection control of the motor is realized. The snow melting machine can be widely applied to the technical field of snow melting machines.

Description

Technical Field

[0001] The present invention relates to the technical field of snow melting machines, and in particular to a motor protection control method and system for a snow melting machine. Background Art

[0002] A slush machine is a device used to create a cool, delicious smoothie (i.e., a slush-like smoothie drink) from various juices or liquid beverages. During the slush production process, a slush machine typically controls a motor to drive a scraper, stirring the slush in the bucket. However, excessive and hard slush can freeze the scraper, causing the motor to stall, hindering the slush production process. Prolonged stalling can even burn out the motor, significantly impacting the safety, lifespan, and stability of the slush machine and increasing maintenance costs.

[0003] Snow melters currently on the market typically use a shaded-pole motor to drive a scraper to achieve stirring, and the motor is protected by detecting the shaded-pole motor's current. The shaded-pole motor's current is detected in real time while the snow melter is operating. As the raw material freezes, the resistance of the stirring motor increases accordingly with the hardness of the raw material, causing the detected current to change. When the preset current value is reached, the compressor is controlled to shut down, allowing the shaded-pole motor to maintain a constant speed and continue stirring the frozen raw material to form the desired smoothie. However, the detected current in this control method is easily affected by fluctuations in the operating environment temperature, resulting in large errors in the shaded-pole motor's current detection data and prone to misjudgment, affecting the normal operation of the motor and even causing the motor to stall, significantly reducing the motor's service life and the operation of the snow melter.

[0004] Some snow melters protect the motor by detecting its speed. While the snow melter is operating, the motor's speed is monitored in real time and compared against a set speed threshold. When the speed falls below the threshold, the motor is stopped. However, motor speed is affected by various factors, such as excessive ice cream in the ice bucket causing the speed to drop. Motor stalling is not the only possible cause, so this protection method is not precise and can lead to misjudgments, affecting the motor's normal operation. Summary of the Invention

[0005] In order to solve the above technical problems, the object of the present invention is to provide a motor protection control method and system for a snow melter, which can accurately detect the motor blocking condition and realize motor protection control.

[0006] The first technical solution adopted by the present invention is: a motor protection control method for a snow melter, comprising the following steps:

[0007] S101, obtaining current data of the stirring motor and calculating the current difference between the previous time node and the current time node; obtaining speed data of the stirring motor based on the grating encoder and calculating the speed difference between the previous time node and the current time node;

[0008] S102, calculating a rate of change of current relative to speed based on the current difference and the speed difference;

[0009] S103, determining whether the rate of change of the current relative to the rotational speed is within a preset rate of change range; if not, controlling the stirring motor to stop working and executing an abnormality handling mode; if yes, initializing an abnormality status value and executing step S104;

[0010] S104, determining whether the speed difference is greater than a first preset threshold; if so, increasing the abnormal state value by 1 based on the initial abnormal state value; if not, maintaining the initial abnormal state value unchanged;

[0011] S105: Determine whether the abnormal state value is greater than a second preset threshold value. If yes, control the compressor to stop working and execute step S106; if no, control the compressor to continue cooling and return to step S101;

[0012] S106: Execute abnormal adjustment mode, and return to step S101 after the mode ends.

[0013] Furthermore, the preset change rate range is determined based on the following:

[0014] Obtain the current data and speed data of the stirring motor when it is no-load, and calculate the change rate of the current relative to the speed when the stirring motor is no-load;

[0015] Obtain the current data and speed data of the stirring motor when it is fully loaded, and calculate the rate of change of the current relative to the speed when the stirring motor is fully loaded;

[0016] The change rate of the current relative to the speed when the stirring motor is unloaded is used as the minimum threshold point of the preset change rate range, and the change rate of the current relative to the speed when the stirring motor is fully loaded is used as the maximum threshold point of the preset change rate range to obtain the preset change rate range.

[0017] Furthermore, the initialization of the abnormal state value is to assign an abnormal state initial value to the abnormal state value; the abnormal state initial value is the abnormal state value of the previous cycle; if the abnormal state value of the previous cycle does not exist, the abnormal state initial value is 0.

[0018] Furthermore, the steps of the exception handling mode include:

[0019] Controlling the stirring motor to reverse direction;

[0020] Obtain the current data of the stirring motor and calculate the current difference between the stirring motor at the previous time node and the current time node;

[0021] The speed data of the stirring motor is obtained based on the grating encoder, and the speed difference between the stirring motor at the previous time node and the current time node is calculated;

[0022] Calculating a rate of change of current relative to speed based on the current difference and the speed difference;

[0023] Determine whether the change rate of the reversing current relative to the reversing speed is within a preset change rate range. If not, control the stirring motor to stop working and execute the alarm mode; if yes, keep the stirring motor in the reverse state and return to step S101.

[0024] Furthermore, the steps of the alarm mode include:

[0025] Perform alarm timing, issue error indication, and record alarm time;

[0026] When the alarm time is greater than the first preset alarm time, the compressor is controlled to stop working;

[0027] When the alarm time is greater than the second preset alarm time, entering the standby state;

[0028] Wherein, the second preset alarm time is greater than the first preset alarm time.

[0029] Furthermore, the abnormal adjustment mode includes the following steps:

[0030] Measure the waiting time and record the waiting time;

[0031] Determine whether the waiting time is greater than a preset time threshold, and when the waiting time is determined to be yes, end the abnormal adjustment mode and clear the abnormal state value;

[0032] When the waiting time is judged as no, the temperature data in the ice making chamber is obtained, and the temperature change rate during the waiting time is calculated; then it is judged whether the temperature change rate during the waiting time is greater than the preset temperature change rate. When the temperature change rate is judged as yes, the abnormal adjustment mode ends and the abnormal state value is cleared; when the temperature change rate is judged as no, then the waiting timing step is returned to.

[0033] Furthermore, the rate of change of the current relative to the speed is calculated as follows:

[0034]

[0035] Where k represents the rate of change of current relative to speed; Δi represents the current difference; Δv represents the speed difference; it-1 Indicates the current of the node at the previous time; i t Indicates the current at the current time node; v t-1 Indicates the speed of the previous time node; v t Indicates the speed of the current time node.

[0036] The second technical solution adopted by the present invention is: a motor protection control system for a snow melter, including a grating encoder, an infrared photoelectric switch, a Hall effect sensor and a main controller, wherein:

[0037] The grating encoder is mounted on the rotating shaft at the rear end of the stirring motor, the infrared photoelectric switch is located on one side of the grating encoder, and the Hall effect sensor is connected in series with the power port of the stirring motor; the grating encoder is used to detect the speed data of the stirring motor; the Hall effect sensor is used to detect the current data of the stirring motor;

[0038] The main controller includes a data acquisition module, a change rate calculation module, a first transmission blockage judgment module, a second transmission blockage judgment module, an abnormal state judgment module, an abnormality processing module, an abnormality adjustment module and an alarm module;

[0039] The data acquisition module is used to execute the step S101;

[0040] The change rate calculation module is used to perform the step S102;

[0041] The first transmission blockage judgment module is used to execute the step S103;

[0042] The second transmission blockage judgment module is used to execute the step S104;

[0043] The abnormal state judgment module is used to execute the step S105;

[0044] The abnormal adjustment module is used to execute the steps of the abnormal adjustment mode;

[0045] The exception handling module is used to execute the steps of the exception handling mode;

[0046] The alarm module is used to execute the steps of the alarm mode.

[0047] The beneficial effects of the present invention are: the present invention proposes a motor protection control method for a snow melter, proposes to use the current difference and the speed difference to calculate the rate of change of current relative to the speed, and use the rate of change of current relative to the speed to make an initial judgment on the stall. When the motor is about to stall, the motor current increases, but the motor speed becomes lower, which is reflected in the rate of change of current relative to the speed as the coefficient of change suddenly changes from positive to negative. Therefore, compared with using motor speed data and motor current data to judge the stall, the judgment of the rate of change of current relative to the speed is more accurate and intuitive.

[0048] The present invention also proposes a judgment algorithm that combines the abnormal state value and the speed difference between the previous time node and the current time node of the motor. The speed difference between the previous time node and the current time node can be used to distinguish between the situation of slight motor jam and the situation of excessive load in the ice bucket. Both groups will cause the motor speed to decrease; but slight motor jam causes the motor speed to continue to decrease, while excessive load in the ice bucket causes the motor speed to stabilize after decrease; under the judgment algorithm of the present invention, slight motor jam will cause the abnormal state value to continue to increase, while excessive load in the ice bucket will not cause the abnormal state value to continue to increase, thereby reducing the delay in the normal operation of the snow melter due to the misjudgment of slight motor jam.

[0049] The present invention also proposes an abnormality processing mode, which automatically processes the motor blocking situation by reversing the stirring motor.

[0050] The present invention also proposes an abnormal adjustment mode, which reflects the decrease in hardness of the smoothie after the compressor is turned off by calculating the temperature change rate during the waiting time; if the temperature change rate during the waiting time meets the preset conditions, the abnormal adjustment can be ended in advance to reduce the delay caused by the abnormal adjustment.

[0051] The present invention provides a motor protection control system for a snow melter, which can accurately detect the motor's stall condition and implement motor protection control. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a flow chart of a motor protection control method for a snow melter according to the present invention;

[0053] Figure 2 This is a schematic diagram of the module structure of a motor protection control system for a snow melter according to the present invention;

[0054] Figure 3 This is a schematic diagram of a main controller module of a motor protection control system for a snow melter according to the present invention;

[0055] Description of the accompanying drawings: 1. Grating encoder; 2. Infrared photoelectric switch; 3. Hall effect sensor; 4. Main controller; 5. Stirring motor. DETAILED DESCRIPTION

[0056] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the embodiments of the present invention, and should not be construed as limiting the present invention.

[0057] In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0058] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0059] In the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," "fixed," etc. should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on specific circumstances.

[0060] Reference Figure 1 A motor protection control method for a snow melter comprises the following steps:

[0061] S101, obtaining current data of the stirring motor and calculating the current difference between the previous time node and the current time node; obtaining speed data of the stirring motor based on the grating encoder and calculating the speed difference between the previous time node and the current time node;

[0062] Specifically, a specific embodiment of the present invention utilizes a Hall effect sensor to obtain current data from a stirring motor. The data detected by the Hall effect sensor is not easily affected by temperature or external factors, thereby effectively improving the accuracy of the detected data. The Hall effect sensor is connected in series to the power port of the stirring motor. The current of the stirring motor flows through the built-in wire of the Hall effect sensor through the power port and generates an encircling magnetic field according to Ampere's law. The encircling magnetic field acts perpendicularly on the Hall element within the Hall effect sensor, generating a weak induced voltage. The circuit within the Hall effect sensor amplifies and linearizes the induced voltage and outputs a standard voltage signal. The output standard voltage signal can directly reflect the current data of the stirring motor. For example, when the output standard voltage signal of the ACS712-5A Hall effect sensor is 2.5V, the corresponding stirring motor current is 0A. Every change of 0.185V in the output standard voltage signal corresponds to a change of 1A in the stirring motor current.

[0063] Specifically, the time interval between the previous time node and the current time node in the specific embodiment of the present invention is preferably 20 seconds; and the previous time node in the specific embodiment of the present invention is selected as the stable execution stage of the forward or reverse rotation of the stirring motor. The motor has just started (whether it is forward rotation or reverse rotation), and the stirring motor is in the fast acceleration stage. The current data and speed data in this stage are not used as the data source for calculating the current difference and speed difference.

[0064] Specifically, refer to Figure 2 In a specific embodiment of the present invention, a grating encoder 1 is used to obtain the speed data of the stirring motor 5. The grating encoder 1 is installed on the rotating shaft at the rear end of the stirring motor 5. The rotational motion of the stirring motor 5 is converted into an electrical pulse signal through optical principles, thereby accurately detecting the speed data of the stirring motor 5. An infrared photoelectric switch 2 is provided on one side of the grating encoder 1 for triggering a zero position signal, initializing the position of the grating encoder 1, and realizing zero position calibration.

[0065] S102, calculating a rate of change of current relative to speed based on the current difference and the speed difference;

[0066] Specifically, the rate of change of current relative to speed is calculated as follows:

[0067]

[0068] Where k represents the rate of change of current relative to speed; Δi represents the current difference; Δv represents the speed difference; i t-1 Indicates the current of the node at the previous time; i t Indicates the current at the current time node; v t-1 Indicates the speed of the previous time node; v t Indicates the speed of the current time node.

[0069] S103, determining whether the rate of change of the current relative to the rotational speed is within a preset rate of change range; if not, controlling the stirring motor to stop working and executing an abnormality handling mode; if yes, initializing an abnormality status value and executing step S104;

[0070] Specifically, the preset change rate range is determined based on the following:

[0071] Obtain the current and speed data of the stirring motor when it is unloaded (the ice bucket is empty), and calculate the rate of change of the current relative to the speed when the stirring motor is unloaded;

[0072] Obtain the current and speed data of the stirring motor when it is fully loaded (the ice bucket is full), and calculate the rate of change of the current relative to the speed when the stirring motor is fully loaded;

[0073] When the stirring motor is in normal operation, the speed of the stirring motor is the fastest and the current of the stirring motor is the smallest when it is idling. Therefore, the rate of change of the current relative to the speed is the smallest when it is idling. The speed of the stirring motor is the lowest and the current of the stirring motor is the largest when it is fully loaded. Therefore, the rate of change of the current relative to the speed is the largest when it is fully loaded.

[0074] The preset rate of change range is obtained by taking the rate of change of the current relative to the speed when the stirring motor is unloaded as the minimum threshold point of the preset rate of change range, and taking the rate of change of the current relative to the speed when the stirring motor is fully loaded as the maximum threshold point of the preset rate of change range. In this way, the preset rate of change range can represent the rate of change range of the current relative to the speed when the stirring motor is in normal operation.

[0075] If the change rate of the current relative to the speed of the stirring motor is not within the preset change rate range, it means that the stirring motor is in a serious stall situation, and the stirring motor is controlled to stop working and execute the abnormal processing mode.

[0076] Specifically, the steps of the exception handling mode include:

[0077] Controlling the stirring motor to reverse direction;

[0078] Obtain the current data of the stirring motor and calculate the current difference between the stirring motor at the previous time node and the current time node;

[0079] The speed data of the stirring motor is obtained based on the grating encoder, and the speed difference between the stirring motor at the previous time node and the current time node is calculated;

[0080] Calculating a rate of change of current relative to speed based on the current difference and the speed difference;

[0081] Determine whether the change rate of the reversing current relative to the reversing speed is within a preset change rate range. If not, control the stirring motor to stop working and execute the alarm mode; if yes, keep the stirring motor in the reverse state and return to step S101.

[0082] The abnormal handling mode is an automatic processing mode performed when the stirring motor is in a serious stall situation, and attempts to solve the stall problem by reversing the stirring motor. In the abnormal handling mode, it is judged whether the rate of change of the reversing current relative to the reversing speed is within the preset rate of change range. If it is judged as yes, it means that the stall problem of the stirring motor has been solved by reversing the stirring motor, and the stirring motor is in normal working condition. If it is judged as no, it means that the stall problem of the stirring motor has not been solved by reversing the stirring motor, and the more serious impact of the motor stall has not been avoided, and the alarm mode is executed.

[0083] Specifically, the steps of the alarm mode include:

[0084] Perform alarm timing, issue error indication, and record alarm time;

[0085] When the alarm time is greater than the first preset alarm time, the compressor is controlled to stop working;

[0086] When the alarm time is greater than the second preset alarm time, entering the standby state;

[0087] Wherein, the second preset alarm time is greater than the first preset alarm time.

[0088] It should be noted that the alarm mode is after the stirring motor stops working; when the alarm time is greater than the second preset alarm time, the device enters standby mode, waiting for the user to perform maintenance and inspection work, thereby protecting the equipment, preventing further abnormalities in related equipment, and improving equipment safety. Of course, user maintenance work can be intervened at any point in the alarm mode. After the user finds the error indication, maintenance and inspection work are carried out, and the alarm timer and alarm mode end.

[0089] Initializing the abnormal state value is to assign an abnormal state initial value to the abnormal state value;

[0090] Specifically, the initial value of the abnormal state is generally the abnormal state value of the previous cycle. If the abnormal adjustment mode has been executed in the previous cycle, the abnormal adjustment mode will clear the abnormal state value, and the initial value of the abnormal state of this cycle is 0; if the abnormal state value of the previous cycle does not exist, the initial value of the abnormal state is 0. The situation where the abnormal state value does not exist usually occurs when the stirring motor just starts working or when the stirring motor is controlled to stop working.

[0091] S104, determining whether the speed difference is greater than a first preset threshold; if so, increasing the abnormal state value by 1 based on the initial abnormal state value; if not, maintaining the initial abnormal state value unchanged;

[0092] Specifically, both a minor motor jam and an excessive ice bucket load will cause the motor speed to decrease and the motor current to increase. It's difficult to distinguish between these two situations using step S104. If the minor motor jam is ignored, the jam can easily worsen and develop into a severe motor jam. Therefore, accurately distinguishing between the two is crucial. The present invention distinguishes between minor motor jams and excessive ice bucket loads by setting an abnormal state value. When the motor is slightly jammed, the motor speed continuously decreases. When the ice bucket is overloaded, the motor speed decreases and then stabilizes. Therefore, the continuous reduction in motor speed is key to distinguishing between these situations.

[0093] The situation of continuous reduction is detected by setting a first preset threshold and an abnormal state value; the first preset threshold is not fixed. In a specific embodiment of the present invention, the first preset threshold is set to 10% of the motor speed at the previous time node. When it is detected that the motor speed difference is higher than the first preset threshold within 1 cycle, the abnormal state value is increased by 1. Therefore, the continuous reduction in the motor speed will be obviously manifested as a continuous increase in the abnormal state value.

[0094] S105: Determine whether the abnormal state value is greater than a second preset threshold value. If yes, control the compressor to stop working and execute step S106; if no, control the compressor to continue cooling and return to step S101;

[0095] Specifically, in a specific embodiment of the present invention, the second preset threshold is preferably 5. If the abnormal state value is greater than the second preset threshold, it means that the stirring motor is in a slightly blocked state.

[0096] S106: Execute abnormal adjustment mode, and return to step S101 after the mode ends.

[0097] Specifically, the steps of the abnormal adjustment mode include:

[0098] Measure the waiting time and record the waiting time;

[0099] Determine whether the waiting time is greater than a preset time threshold, and when the waiting time is determined to be yes, end the abnormal adjustment mode and clear the abnormal state value;

[0100] When the waiting time is judged as no, the temperature data in the ice making chamber is obtained, and the temperature change rate during the waiting time is calculated; then it is judged whether the temperature change rate during the waiting time is greater than the preset temperature change rate. When the temperature change rate is judged as yes, the abnormal adjustment mode ends and the abnormal state value is cleared; when the temperature change rate is judged as no, then the waiting timing step is returned to.

[0101] The preset time threshold is the time it takes for the smoothie in the ice bucket, at normal temperature and pressure, to drop from a first hardness that causes severe motor blocking to a second hardness that does not. Therefore, if the waiting time exceeds the preset time threshold, it is assumed that the hardness of the smoothie in the ice bucket has dropped to a level that no longer affects the operation of the blending motor. Of course, in high temperatures, the hardness of the smoothie can drop faster than expected. Therefore, the temperature change rate during the waiting period is calculated to reflect the drop in hardness after the compressor is turned off. If the temperature change rate during the waiting period meets the preset conditions, the abnormal adjustment mode is terminated early to reduce unnecessary waiting time. Executing the abnormal adjustment mode resets the abnormal status value to zero.

[0102] Reference Figure 2 A motor protection control system for a snow melter includes a grating encoder, an infrared photoelectric switch, a Hall effect sensor, and a main controller, wherein:

[0103] The grating encoder 1 is installed on the rotating shaft at the rear end of the stirring motor 5, the infrared photoelectric switch 2 is arranged on one side of the grating encoder 1, and the Hall effect sensor 3 is connected in series with the power port of the stirring motor 5 to detect the current data of the stirring motor 5; the grating encoder 1 is used to detect the speed data of the stirring motor 5; the infrared photoelectric switch 2 is used to trigger the zero position signal to realize the zero position calibration of the grating encoder 1; the Hall effect sensor 3 is connected to the main controller 4 to transmit the current data of the stirring motor 5 to the main controller 4; the grating encoder 1 is connected to the main controller 4 to transmit the speed data of the stirring motor 5 to the main controller 4.

[0104] Reference Figure 3 , the main controller includes a data acquisition module, a change rate calculation module, a first transfer jam judgment module, a second transfer jam judgment module, an abnormal state judgment module, an abnormality processing module, an abnormality adjustment module and an alarm module;

[0105] The data acquisition module is used to execute the step S101;

[0106] The change rate calculation module is used to perform the step S102;

[0107] The first transmission blockage judgment module is used to execute the step S103;

[0108] The second transmission blockage judgment module is used to execute the step S104;

[0109] The abnormal state judgment module is used to execute the step S105;

[0110] The abnormal adjustment module is used to execute the steps of the abnormal adjustment mode;

[0111] The exception handling module is used to execute the steps of the exception handling mode;

[0112] The alarm module is used to execute the steps of the alarm mode.

[0113] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A motor protection control method for a snow melter, characterized in that: The following steps are involved: S101, obtaining current data of the stirring motor and calculating the current difference between the previous time node and the current time node; obtaining speed data of the stirring motor based on the grating encoder and calculating the speed difference between the previous time node and the current time node; S102, calculating a rate of change of current relative to speed based on the current difference and the speed difference; S103, determining whether the rate of change of the current relative to the rotational speed is within a preset rate of change range, and if not, controlling the stirring motor to stop working and executing an abnormality handling mode; If the judgment is yes, initialize the abnormal state value and execute step S104; S104, determining whether the speed difference is greater than a first preset threshold; if so, increasing the abnormal state value by 1 based on the initial abnormal state value; if not, maintaining the initial abnormal state value unchanged; S105: Determine whether the abnormal state value is greater than a second preset threshold value. If yes, control the compressor to stop working and execute step S106; if no, control the compressor to continue cooling and return to step S101; S106: Execute abnormal adjustment mode, and return to step S101 after the mode ends.

2. A snow melter motor protection control method according to claim 1, characterized in that: The preset change rate range is determined based on the following: Obtain the current data and speed data of the stirring motor when it is no-load, and calculate the change rate of the current relative to the speed when the stirring motor is no-load; Obtain the current data and speed data of the stirring motor when it is fully loaded, and calculate the rate of change of the current relative to the speed when the stirring motor is fully loaded; The change rate of the current relative to the speed when the stirring motor is unloaded is used as the minimum threshold point of the preset change rate range, and the change rate of the current relative to the speed when the stirring motor is fully loaded is used as the maximum threshold point of the preset change rate range to obtain the preset change rate range.

3. The motor protection control method for a snow melter according to claim 1, characterized in that: The initialization of the abnormal state value is to assign an abnormal state initial value to the abnormal state value; the abnormal state initial value is the abnormal state value of the previous cycle; if the abnormal state value of the previous cycle does not exist, the abnormal state initial value is 0.

4. The motor protection control method for a snow melter according to claim 1, characterized in that: The steps of the exception handling mode include: Controlling the stirring motor to reverse direction; Obtain the current data of the stirring motor and calculate the current difference between the stirring motor at the previous time node and the current time node; The speed data of the stirring motor is obtained based on the grating encoder, and the speed difference between the stirring motor at the previous time node and the current time node is calculated; Calculating a rate of change of current relative to speed based on the current difference and the speed difference; Determine whether the change rate of the reversing current relative to the reversing speed is within a preset change rate range. If not, control the stirring motor to stop working and execute the alarm mode; if yes, keep the stirring motor in the reverse state and return to step S101.

5. A snow melt machine motor protection control method according to claim 4, characterized in that: The steps of the alarm mode include: Perform alarm timing, issue error indication, and record alarm time; When the alarm time is greater than the first preset alarm time, the compressor is controlled to stop working; When the alarm time is greater than the second preset alarm time, entering the standby state; Wherein, the second preset alarm time is greater than the first preset alarm time.

6. A snow melt machine motor protection control method according to claim 1, characterized in that: The steps of the abnormal adjustment mode include: Measure the waiting time and record the waiting time; Determine whether the waiting time is greater than a preset time threshold, and when the waiting time is determined to be yes, end the abnormal adjustment mode and clear the abnormal state value; When the waiting time is judged as no, the temperature data in the ice making chamber is obtained, and the temperature change rate during the waiting time is calculated; then it is judged whether the temperature change rate during the waiting time is greater than the preset temperature change rate. When the temperature change rate is judged as yes, the abnormal adjustment mode ends and the abnormal state value is cleared; when the temperature change rate is judged as no, then the waiting timing step is returned to.

7. The motor protection control method for a snow melter according to claim 1, characterized in that: The rate of change of the current relative to the speed is calculated as follows: Where k represents the rate of change of current relative to speed; Δi represents the current difference; Δv represents the speed difference; i t-1 Indicates the current of the node at the previous time; i t Indicates the current at the current time node; v t-1 Indicates the speed of the previous time node; v t Indicates the speed of the current time node.

8. A motor protection control system for a snow melter, characterized in that: include: Grating encoder, infrared photoelectric switch, Hall effect sensor and main controller, including: The grating encoder is mounted on the rotating shaft at the rear end of the stirring motor, the infrared photoelectric switch is located on one side of the grating encoder, and the Hall effect sensor is connected in series with the power port of the stirring motor; the grating encoder is used to detect the speed data of the stirring motor; the Hall effect sensor is used to detect the current data of the stirring motor; The main controller includes a data acquisition module, a change rate calculation module, a first transmission blockage judgment module, a second transmission blockage judgment module, an abnormal state judgment module, an abnormality processing module, an abnormality adjustment module and an alarm module; The data acquisition module is used to execute the step S101; The change rate calculation module is used to perform the step S102; The first transmission blockage judgment module is used to execute the step S103; The second transmission blockage judgment module is used to execute the step S104; The abnormal state judgment module is used to execute the step S105; The abnormal adjustment module is used to execute the steps of the abnormal adjustment mode; The exception handling module is used to execute the steps of the exception handling mode; The alarm module is used to execute the steps of the alarm mode.

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