Motor protection method, motor system and computer equipment

Abstract

The invention belongs to the technical field of motor and frequency converter protection, and particularly relates to a motor protection method, a motor system and computer equipment, and the method comprises the steps: judging the current working mode of a motor: if the motor is in a power frequency mode, inputting a power frequency mode soft pressing plate and a universal soft pressing plate to achieve the power frequency mode protection of the motor; if the motor is in the frequency conversion mode, the frequency conversion mode soft pressing plate and the universal soft pressing plate are put into use to realize frequency conversion mode protection of the motor; wherein the power frequency mode soft pressing plate is used for realizing switching of a non-universal protection function in a power frequency mode, the frequency conversion mode soft pressing plate is used for realizing switching of a non-universal protection function in a frequency conversion mode, and the universal soft pressing plate is used for realizing switching of a universal protection function in the power frequency mode and the frequency conversion mode. The protection constant value of each protection function is a preset value. And the protection constant value of each protection function is the preset value, so that configuration is not needed during use, and normal operation of the protection functions is prevented from being influenced by errors during configuration.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor protection, and in particular relates to a motor protection method, a motor system and a computer device. Background Art

[0002] By adjusting the frequency of the motor through the inverter, the soft start of the motor can be achieved. During the variable frequency starting process of the motor, the frequency of the power supply is controlled by the inverter, which can limit the current when the motor starts, thereby achieving easy starting of the motor, and at the same time protecting the motor and the inverter from electromagnetic interference. The speed of the motor can also be accurately controlled by adjusting the output frequency of the inverter. Compared with the traditional starting method, the variable frequency starting of the motor can make the motor speed increase rapidly in a shorter time to reach the rated speed, and can achieve accurate adjustment and control of the speed.

[0003] Because the heating curve of the motor is different in variable frequency mode and power frequency mode, such as Figure 1 As shown, the protection settings that need to be configured are also different. The traditional technical solution in which the motor protection strategy and protection settings remain unchanged in the power frequency mode and variable frequency mode cannot provide good protection effects in both modes.

[0004] Therefore, in order to realize the protection of the two modes of the motor, the existing technology usually adopts a technical solution with a fixed protection strategy and a non-fixed protection setting value. By setting a set of protection strategies and then identifying the state of the motor, different protection settings are configured for the two modes to adapt to different heating curves. However, the above technical solution needs to configure the corresponding protection setting value in the protection strategy according to the current mode of the motor. Before the protection strategy is executed, each protection setting value needs to be reconfigured. The configuration process is cumbersome and it is easy to have protection setting value configuration errors. Summary of the invention

[0005] The object of the present invention is to provide a motor protection method, a motor system and a computer device to solve the technical problem in the prior art that the protection constants of the power frequency mode and the variable frequency mode need to be configured according to the motor mode, which affects the normal operation of the motor protection function due to the easy error in the protection constant configuration.

[0006] In order to solve the above technical problems, the present invention provides a motor protection method, which comprises:

[0007] Determine the current working mode of the motor: if the motor is in the power frequency mode, the power frequency mode soft pressure plate and the general soft pressure plate are put into operation to realize the power frequency mode protection of the motor; if the motor is in the variable frequency mode, the variable frequency mode soft pressure plate and the general soft pressure plate are put into operation to realize the variable frequency mode protection of the motor;

[0008] Among them, the industrial frequency mode soft pressure plate is used to realize the activation and deactivation of non-universal protection functions in the industrial frequency mode, the variable frequency mode soft pressure plate is used to realize the activation and deactivation of non-universal protection functions in the variable frequency mode, and the universal soft pressure plate is used to realize the activation and deactivation of universal protection functions in the industrial frequency mode and the variable frequency mode. The protection setting value of each protection function is a preset value.

[0009] Furthermore, the universal soft pressure plate includes one, two or all of the FC overcurrent abnormal protection soft pressure plate, the CT abnormal protection soft pressure plate and the PT abnormal protection soft pressure plate, which are respectively used to implement the activation and deactivation of the FC overcurrent abnormal protection function, the CT abnormal protection function and the PT abnormal protection function.

[0010] Furthermore, the power frequency mode soft pressure plate includes one, two or more of the three-stage overcurrent protection soft pressure plate, the two-stage negative-sequence overcurrent protection soft pressure plate, the two-stage zero-sequence overcurrent protection soft pressure plate and the positive-sequence overcurrent protection soft pressure plate in the power frequency mode, which are respectively used to realize the activation and deactivation of the three-stage overcurrent protection function, the two-stage negative-sequence overcurrent protection function, the two-stage zero-sequence overcurrent protection function and the positive-sequence overcurrent protection function in the power frequency mode.

[0011] Furthermore, the variable frequency mode soft pressure plate includes one, two or more of the three-stage overcurrent protection soft pressure plate, the two-stage negative-sequence overcurrent protection soft pressure plate, the two-stage zero-sequence overcurrent protection soft pressure plate and the positive-sequence overcurrent protection soft pressure plate in the variable frequency mode; they are respectively used to realize the activation and deactivation of the three-stage overcurrent protection function, the two-stage negative-sequence overcurrent protection function, the two-stage zero-sequence overcurrent protection function and the positive-sequence overcurrent protection function in the variable frequency mode.

[0012] Furthermore, the variable frequency mode soft pressure plate includes one, two or more of the three-stage overcurrent protection soft pressure plate, the two-stage negative-sequence overcurrent protection soft pressure plate, the two-stage zero-sequence overcurrent protection soft pressure plate and the positive-sequence overcurrent protection soft pressure plate in the variable frequency mode; they are respectively used to realize the activation and deactivation of the three-stage overcurrent protection function, the two-stage negative-sequence overcurrent protection function, the two-stage zero-sequence overcurrent protection function and the positive-sequence overcurrent protection function in the variable frequency mode; the protection constants of the same protection function in the power frequency mode and the variable frequency mode are different.

[0013] Furthermore, the power frequency mode soft pressure plate includes a stall protection soft pressure plate, an overheat protection soft pressure plate and a motor start timeout protection soft pressure plate, which are respectively used to realize the activation and deactivation of the motor stall protection function, the motor overheat protection function and the motor start timeout protection function.

[0014] Furthermore, the method for determining the current working mode of the motor is as follows: if the bypass switch connected in parallel with the frequency converter is in an open state, the motor is in a variable frequency mode; if the bypass switch is in a closed state, the motor is in an industrial frequency mode.

[0015] The present invention is an improved invention creation, and its beneficial effects are as follows: the motor protection method of the present invention controls the activation and deactivation of different motor protection functions through a soft pressure plate, and the protection setting value of each protection function is a preset value. According to the motor modes corresponding to different protection functions, a general soft pressure plate, a power frequency mode soft pressure plate and a variable frequency mode soft pressure plate are set. The general soft pressure plate needs to be activated in both modes, and the protection setting values ​​of different protection functions are preset values, which do not need to be configured during use, and do not need to be operated when the motor mode is switched. Then, the activation and deactivation states of the corresponding variable frequency mode soft pressure plate and the power frequency mode soft pressure plate are adjusted to complete the switching of the motor protection mode, and there is no need to set the corresponding protection setting value according to the motor mode. The original scheme of adapting to the change of the motor mode by modifying the protection setting value is modified to keep the protection setting value unchanged, and the activation and deactivation of the corresponding protection function is controlled by the soft pressure plate to adapt to different motor modes. When the motor mode is switched, there is no need to configure the protection setting value again, and the state change of the soft pressure plate is relatively easy, making the switching of the motor protection mode simpler and more effective, and less prone to errors.

[0016] To solve the above technical problems, the present invention further provides a computer device, including a processor, wherein the processor implements the method steps described in the motor protection method of the present invention when executing a computer program.

[0017] The present invention is an improved invention creation, and its beneficial effects are as follows: the computer equipment of the present invention controls the activation and deactivation of different motor protection functions through a soft pressure plate, and the protection setting value of each protection function is a preset value. According to the motor modes corresponding to different protection functions, a general soft pressure plate, a power frequency mode soft pressure plate and a variable frequency mode soft pressure plate are set, and the general soft pressure plate needs to be activated in both modes. The protection setting values ​​of different protection functions are preset values, which do not need to be configured during use, and do not need to be operated when the motor mode is switched. Then, the activation and deactivation states of the corresponding variable frequency mode soft pressure plate and the power frequency mode soft pressure plate are adjusted to complete the switching of the motor protection mode, and there is no need to set the corresponding protection setting value according to the motor mode. The original scheme of adapting to the change of the motor mode by modifying the protection setting value is modified to keep the protection setting value unchanged, and the activation and deactivation of the corresponding protection function is controlled by the soft pressure plate to adapt to different motor modes. When the motor mode is switched, there is no need to configure the protection setting value again, and the state change of the soft pressure plate is relatively easy, making the switching of the motor protection mode simpler and more effective, and less prone to error.

[0018] To solve the above technical problems, the present invention further provides a motor system, including a motor, a frequency converter and a processor, wherein the processor implements the method steps described in the motor protection method of the present invention when executing a computer program.

[0019] The present invention is an improved invention creation, and its beneficial effects are as follows: the motor system of the present invention controls the activation and deactivation of different motor protection functions through a soft pressure plate, and the protection setting value of each protection function is a preset value. According to the motor modes corresponding to different protection functions, a general soft pressure plate, a power frequency mode soft pressure plate and a variable frequency mode soft pressure plate are set. The general soft pressure plate needs to be activated in both modes, and the protection setting values ​​of different protection functions are preset values, which do not need to be configured during use, and do not need to be operated when the motor mode is switched. Then, the activation and deactivation states of the corresponding variable frequency mode soft pressure plate and the power frequency mode soft pressure plate are adjusted to complete the switching of the motor protection mode, and there is no need to set the corresponding protection setting value according to the motor mode. The original scheme of adapting to the change of the motor mode by modifying the protection setting value is modified to keep the protection setting value unchanged, and the activation and deactivation of the corresponding protection function is controlled by the soft pressure plate to adapt to different motor modes. When the motor mode is switched, there is no need to configure the protection setting value again, and the state change of the soft pressure plate is relatively easy, making the switching of the motor protection mode simpler and more effective, and less prone to errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a heating curve diagram of a motor in different modes in the background technology of the present invention;

[0021] Figure 2 is a primary system wiring diagram of a motor of an embodiment of a motor system of the present invention;

[0022] Figure 3 It is a flow chart of a motor protection method according to an embodiment of a motor system of the present invention. DETAILED DESCRIPTION

[0023] A motor protection method, a motor system and a computer device of the present invention modify the original scheme of adapting to the change of motor mode by modifying the protection constant value, and modify the protection constant value to remain unchanged, and adapt to different motor modes by controlling the activation and deactivation of the corresponding protection function through a soft pressure plate. When the motor mode is switched, there is no need to configure the protection constant value, and the state of the soft pressure plate can be changed relatively easily, so that the switching of the motor protection mode is simpler, more effective and less prone to errors.

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0025] Motor system example:

[0026] The motor system of this embodiment is taken as an example including a frequency converter driving a motor (motor). The primary system wiring is as follows: Figure 2As shown: K1 and K2 switches ensure that there is no contact point with the main circuit when the inverter is being repaired; K3 is a bypass switch, which is connected in parallel with the inverter and is closed when the inverter is not in use. When the motor is running at the power frequency, the bypass switch K3 is closed, and K1 and K2 are disconnected; when the motor is running at variable frequency, the bypass switch K3 is disconnected, and K1 and K2 are closed.

[0027] The motor system of this embodiment further includes a processor, which is used to execute a computer program to implement the steps of the motor protection method of the present invention. The specific motor protection method is as follows:

[0028] The motor protection method of the present invention divides the protection functions of the motor into two common protection functions in the two modes, non-common protection functions in the power frequency mode and non-common protection functions in the variable frequency mode, and then controls different protection functions by setting a soft pressure plate, thereby realizing the protection of the motor in the power frequency mode and the variable frequency mode respectively.

[0029] like Figure 3 As shown, the motor protection method in this embodiment specifically includes the following steps:

[0030] Step 1: Determine the current working mode of the motor.

[0031] The motor protection method of the present invention determines the state of the motor by the state of the bypass switch K3. When the bypass switch is closed, it can be determined that the motor runs at the industrial frequency. When the bypass switch is open, the motor runs in the variable frequency mode.

[0032] The specific method of realizing automatic switching between the two protection modes of the device through the bypass switch K3 is as follows:

[0033] 1) When the K3 switch provides the "closed" contact, when the K3 switch is in the "closed" contact, it is equivalent to the switch being closed. The "closed" contact is introduced into the "power frequency mode switching" input of the device through hard wiring. When the input is 1 (the "closed" contact is closed, K3 is turned on), the motor is in the power frequency mode; when the input is 0, the motor is in the variable frequency mode.

[0034] 2) When the K3 switch provides a "jump position" contact, when the K3 switch is in the "jump position" contact, it is equivalent to the switch being suspended and not closed. The "jump position" contact is introduced into the "frequency conversion mode switching" input of the device through hard wiring. When the input is 1 (the "jump position" contact is closed, K3 is disconnected), the motor is in the frequency conversion mode; when the input is 0, the motor is in the industrial frequency mode.

[0035] Step 2: Control the corresponding soft pressure plate's insertion and retraction status according to the motor mode.

[0036] If the motor is in the industrial frequency mode, the industrial frequency mode soft pressure plate and the universal soft pressure plate are put into operation to realize the industrial frequency mode protection of the motor; if the motor is in the variable frequency mode, the variable frequency mode soft pressure plate and the universal soft pressure plate are put into operation to realize the variable frequency mode protection of the motor.

[0037] Due to the different fault characteristics of the variable frequency and industrial frequency working modes, the configured protection functions are slightly different.

[0038] The device provides the following protection functions in power frequency mode:

[0039] (1) Three-stage overcurrent protection for motor working current (the first stage provides high and low set values, and the first and second stages have directions);

[0040] (2) Two-stage negative sequence overcurrent protection of motor working current (negative sequence with direction);

[0041] (3) Two-stage zero-sequence overcurrent protection of motor working current;

[0042] (4) Motor overheat protection (restart prohibited in case of overheating);

[0043] (5) Motor stall protection;

[0044] (6) Motor start-up timeout protection;

[0045] (7) Positive sequence overcurrent protection of motor operating current;

[0046] (8) Motor overload protection;

[0047] (9) FC circuit high current lockout;

[0048] (10) CT disconnection alarm;

[0049] (11)PT disconnection alarm.

[0050] The device provides the following protection functions in variable frequency mode:

[0051] (1) Three-stage overcurrent protection for motor operating current;

[0052] (2) Two-stage negative sequence overcurrent protection of motor operating current;

[0053] (3) Two-stage zero-sequence overcurrent protection of motor working current;

[0054] (4) Positive sequence overcurrent protection of motor operating current;

[0055] (5) Motor overload protection;

[0056] (6) FC (fuse and contactor) circuit high current blocking;

[0057] (7) CT (current transformer) disconnection alarm;

[0058] (8) PT (voltage transformer) disconnection alarm.

[0059] Overheat protection, stall protection, and motor start-up timeout protection are unique protection functions in the power frequency mode.

[0060] Although both the power frequency mode and the variable frequency mode have three-stage overcurrent protection, two-stage negative-sequence overcurrent protection, two-stage zero-sequence overcurrent protection and positive-sequence overcurrent protection, the protection settings are different in different modes. Not only are the values ​​of the same type of protection settings different, but the types of protection settings for the three-stage overcurrent protection and two-stage negative-sequence overcurrent protection are also not exactly the same in the power frequency mode and the variable frequency mode.

[0061] In the power frequency mode, the overcurrent protection of the first stage in the three-stage overcurrent protection provides two high and low fixed values. The motor uses the high value of the overcurrent protection during the starting process, and uses the low value of the overcurrent protection during the operation. The three-stage overcurrent protection and the two-stage negative sequence overcurrent protection also include direction settings, which are used to distinguish between external and internal faults of the motor. In the power frequency mode, the direction setting is increased to avoid the situation of false operation of the motor due to external faults. In the variable frequency mode, the direction setting does not need to be increased because when an external fault occurs, the fault removal can protect the inverter. For specific protection content, please refer to Table 1.

[0062] Table 1. Protection functions for power frequency mode, variable frequency mode and common protection functions for both modes

[0063]

[0064]

[0065] In the table indicates the rated value. The specific protection setting values ​​of each protection function can be pre-set in the corresponding range with a step length. After setting, the corresponding protection function is formed, and then the corresponding protection function is controlled by the soft pressure plate. When using it, you only need to set the soft pressure plate's throw-in and throw-out status, and there is no need to configure the corresponding protection setting value.

[0066] Since the protection settings are different in different modes, the three-stage overcurrent, two-stage negative sequence overcurrent, two-stage zero sequence overcurrent protection, positive sequence overcurrent protection and overload protection provide independent protection settings and soft pressure plates for power frequency mode and variable frequency mode; FC overcurrent blocking, CT, PT line break alarm belong to general protection, and the power frequency mode and variable frequency mode share the same settings and soft pressure plates. The final soft pressure plate can be seen in Table 2.

[0067] Table 2. Soft pressure plate table for power frequency mode and variable frequency mode

[0068]

[0069]

[0070] Each soft pressure plate is used to realize the activation and deactivation of its corresponding protection function. For example, the three-stage overcurrent protection soft pressure plate in the variable frequency mode includes the overcurrent stage I soft pressure plate, the overcurrent stage II soft pressure plate and the overcurrent stage III soft pressure plate, which are used to realize the activation and deactivation of the three-stage overcurrent protection function in the variable frequency mode; the three-stage overcurrent protection soft pressure plate in the power frequency mode is used to realize the activation and deactivation of the three-stage overcurrent protection function in the power frequency mode.

[0071] When the bypass switch K3 detects that the motor is in the power frequency mode, the various soft pressure plates in the power frequency mode in Table 2 are set to the activated state, and the universal soft pressure plate is set to the activated state, so that the protection function of the power frequency mode is activated to protect the motor; when the bypass switch K3 detects that the motor is in the variable frequency mode, the various soft pressure plates in the variable frequency mode in Table 2 are set to the activated state, and the universal soft pressure plate is set to the activated state, so that the protection function of the variable frequency mode is activated to protect the motor. The FC overcurrent abnormal protection soft pressure plate, the CT abnormal protection soft pressure plate and the PT abnormal protection soft pressure plate are used to realize the activation and deactivation of the FC overcurrent abnormal protection function, the CT abnormal protection function and the PT abnormal protection function respectively. The three-stage overcurrent protection soft pressure plate, the two-stage negative sequence overcurrent protection soft pressure plate, the two-stage zero sequence overcurrent protection soft pressure plate and the positive sequence overcurrent protection soft pressure plate in the power frequency mode are used to realize the activation and deactivation of the three-stage overcurrent protection function, the two-stage negative sequence overcurrent protection function, the two-stage zero sequence overcurrent protection function and the positive sequence overcurrent protection function in the power frequency mode respectively. The three-stage overcurrent protection soft pressure plate, the two-stage negative-sequence overcurrent protection soft pressure plate, the two-stage zero-sequence overcurrent protection soft pressure plate and the positive-sequence overcurrent protection soft pressure plate in the variable frequency mode are used to realize the activation and deactivation of the three-stage overcurrent protection function, the two-stage negative-sequence overcurrent protection function, the two-stage zero-sequence overcurrent protection function and the positive-sequence overcurrent protection function in the variable frequency mode respectively.

[0072] Through the above method, the present invention directly sets a non-universal protection function of the power frequency mode, a non-universal protection function of the variable frequency mode and a protection function common to the two modes for the power frequency mode and the motor mode of the motor, and sets a soft pressure plate of the power frequency mode, a soft pressure plate of the variable frequency mode and a soft pressure plate common to the two modes, respectively controlling the three protection functions, and the protection setting values ​​of each protection function are preset values. The original scheme of adapting to the change of the motor mode by modifying the protection setting value is modified to keep the protection setting value unchanged, and the corresponding protection function is controlled by the soft pressure plate to adapt to different motor modes. When the motor mode is switched, there is no need to configure the protection setting value, and the state change of the soft pressure plate is relatively easy and not easy to make mistakes. When using, it is only necessary to set the corresponding soft pressure plate to the investment state, and it is not necessary to configure the corresponding protection setting value according to the protection mode, which has the beneficial effects of simple operation and not easy to make mistakes. At the same time, each protection function in the present invention corresponds to a soft pressure plate, which can be invested and withdrawn in units of protection functions. In certain specific working conditions, it is only necessary to start the corresponding protection function, and it is not necessary to invest in the protection strategy of the entire mode, making the protection more flexible.

[0073] Method Example:

[0074] The specific process, principle and beneficial effects of the motor protection method of the present invention have been described in detail in the method embodiment, and will not be repeated in this embodiment.

[0075] Computer equipment example:

[0076] A computer device of the present invention includes a processor, wherein the processor implements the steps of the motor protection method as described in the method embodiment when executing a computer program. The specific steps, principles and beneficial effects of the method have been described in detail in the method embodiment, and will not be repeated in this embodiment.

[0077] The processor may be a microprocessor MCU, a programmable logic device FPGA or other processing device.

Claims

1. A motor protection method, characterized in that: The method includes: Determine the current working mode of the motor: if the motor is in the power frequency mode, the power frequency mode soft pressure plate and the general soft pressure plate are put into operation to realize the power frequency mode protection of the motor; if the motor is in the variable frequency mode, the variable frequency mode soft pressure plate and the general soft pressure plate are put into operation to realize the variable frequency mode protection of the motor; Among them, the industrial frequency mode soft pressure plate is used to realize the activation and deactivation of non-universal protection functions in the industrial frequency mode, the variable frequency mode soft pressure plate is used to realize the activation and deactivation of non-universal protection functions in the variable frequency mode, and the universal soft pressure plate is used to realize the activation and deactivation of universal protection functions in the industrial frequency mode and the variable frequency mode. The protection setting value of each protection function is a preset value.

2. The motor protection method according to claim 1, characterized in that: The universal soft pressure plate includes one, two or all of the FC overcurrent abnormal protection soft pressure plate, the CT abnormal protection soft pressure plate and the PT abnormal protection soft pressure plate, which are respectively used to implement the activation and deactivation of the FC overcurrent abnormal protection function, the CT abnormal protection function and the PT abnormal protection function.

3. The motor protection method according to claim 1, characterized in that: The power frequency mode soft pressure plate includes one, two or more of the three-stage overcurrent protection soft pressure plate, the two-stage negative-sequence overcurrent protection soft pressure plate, the two-stage zero-sequence overcurrent protection soft pressure plate and the positive-sequence overcurrent protection soft pressure plate in the power frequency mode, which are respectively used to realize the activation and deactivation of the three-stage overcurrent protection function, the two-stage negative-sequence overcurrent protection function, the two-stage zero-sequence overcurrent protection function and the positive-sequence overcurrent protection function in the power frequency mode.

4. The motor protection method according to claim 1, characterized in that: The variable frequency mode soft pressure plate includes one, two or more of the three-stage overcurrent protection soft pressure plate, the two-stage negative-sequence overcurrent protection soft pressure plate, the two-stage zero-sequence overcurrent protection soft pressure plate and the positive-sequence overcurrent protection soft pressure plate in the variable frequency mode; they are respectively used to realize the activation and deactivation of the three-stage overcurrent protection function, the two-stage negative-sequence overcurrent protection function, the two-stage zero-sequence overcurrent protection function and the positive-sequence overcurrent protection function in the variable frequency mode.

5. The motor protection method according to claim 3, characterized in that: The variable frequency mode soft pressure plate includes one, two or more of the three-stage overcurrent protection soft pressure plate, the two-stage negative-sequence overcurrent protection soft pressure plate, the two-stage zero-sequence overcurrent protection soft pressure plate and the positive-sequence overcurrent protection soft pressure plate in the variable frequency mode; they are respectively used to realize the activation and deactivation of the three-stage overcurrent protection function, the two-stage negative-sequence overcurrent protection function, the two-stage zero-sequence overcurrent protection function and the positive-sequence overcurrent protection function in the variable frequency mode; the protection constants of the same protection function in the power frequency mode and the variable frequency mode are different.

6. The motor protection method according to claim 1, characterized in that: The power frequency mode soft pressure plate includes a stall protection soft pressure plate, an overheat protection soft pressure plate and a motor start timeout protection soft pressure plate, which are respectively used to implement the motor stall protection function, the motor overheat protection function and the motor start timeout protection function.

7. The motor protection method according to any one of claims 1 to 6, characterized in that: The method for determining the current working mode of the motor is as follows: if the bypass switch connected in parallel with the frequency converter is in an open state, the motor is in a variable frequency mode; if the bypass switch is in a closed state, the motor is in an industrial frequency mode.

8. A computer device comprising a processor, characterized in that: The processor implements the steps of the motor protection method according to any one of claims 1 to 7 when executing the computer program.

9. A motor system, comprising a motor, a frequency converter and a processor, characterized in that: The processor implements the steps of the motor protection method according to any one of claims 1 to 7 when executing the computer program.

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