Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art or the related art.
To this end, a first aspect of the present invention proposes a control method of a compressor.
A second aspect of the present invention provides a control system for a compressor.
A third aspect of the present invention provides a compressor assembly.
A fourth aspect of the present invention provides an air conditioning apparatus.
A fifth aspect of the invention proposes a computer-readable storage medium.
In view of this, a first aspect of the present invention provides a control method of a compressor, including: acquiring the bus voltage of a power supply line of the compressor, and acquiring the working current of the compressor; and adjusting the amplitude limiting value of the command signal of the compressor according to the bus voltage and the working current.
In the technical scheme, when the voltage of the power grid fluctuates, the bus voltage of a power supply line of the compressor also fluctuates along with the fluctuation of the voltage of the power grid. The bus voltage and the working current of the compressor are collected in real time, when the bus voltage fluctuates and the working current is greatly changed, the amplitude limiting value of the instruction signal of the compressor is directly adjusted according to the bus voltage and the working current, on one hand, the operation safety of the compressor is guaranteed, and on the other hand, overcurrent shutdown can be avoided. Compared with the method for avoiding the overcurrent by sending a current limiting instruction (corresponding time second level) through the main control chip, the method has the advantages that the frequency and the current of the compressor are directly pulled by adjusting the amplitude limiting value of the instruction signal of the compressor, the current limiting failure caused by insufficient frequency limiting is avoided, the response speed is higher (millisecond level), the overcurrent shutdown condition caused by power grid fluctuation is effectively reduced, the operation reliability of the compressor is improved, and the operation effect and the user experience of the compressor are ensured.
In addition, the control method of the compressor in the above technical solution provided by the present invention may further have the following additional technical features:
in the above technical solution, the step of adjusting the instruction signal threshold of the compressor according to the bus voltage and the working current specifically includes: on the basis that the bus voltage is smaller than a first bus voltage threshold value and the bus voltage is larger than a second bus voltage threshold value, adjusting a current threshold value corresponding to the working current to be a first working current threshold value; and if the working current is larger than the first working current threshold value, the amplitude limiting value of the regulating instruction signal is reduced to a protection value.
In this solution, if the bus voltage is less than the first bus voltage threshold, but greater than the second bus voltage threshold, the current bus voltage has a falling tendency and the risk of overcurrent shutdown exists, at the moment, the current threshold corresponding to the working current is adjusted to be a first current threshold which is lower than the current threshold corresponding to the overcurrent shutdown, when the working current is larger than or lower than the working current threshold value, the amplitude limiting value of the instruction signal of the compressor is reduced, specifically the amplitude limiting value is reduced to a protection value, namely, the frequency and the current of the compressor are reduced by reducing the amplitude limiting value of the command signal before the working current reaches the threshold value of the overcurrent shutdown, the compressor is limited in a smaller operation mode, the overcurrent shutdown is avoided, and then the operational reliability of the compressor is improved, and the operational effect and the user experience of the compressor are ensured.
In any of the above technical solutions, the step of adjusting the instruction signal threshold of the compressor according to the bus voltage and the working current further includes: adjusting the current threshold corresponding to the working current to be a second working current threshold on the basis of the condition that the bus voltage is smaller than the second bus voltage threshold; if the working current is larger than the second working current threshold, the threshold is adjusted to be reduced to a protection value; wherein the second operating current threshold is less than the first operating current threshold.
In the technical scheme, when the bus voltage is reduced to be smaller than the second bus voltage threshold value, the current power grid fluctuation is large, and the bus voltage reduction range is large. At this time, the current threshold corresponding to the working current is adjusted to be the second working current threshold, and the second working current threshold is smaller than the first working current threshold, namely, the step of reducing the instruction signal threshold is triggered earlier, so that the response speed of frequency reduction and current limiting is further improved, the sudden rise of the working current caused by the rapid drop of the bus voltage is avoided, the operation reliability of the compressor is further improved, and the operation effect and the user experience of the compressor are ensured.
In any of the above technical solutions, after the step of adjusting the current threshold corresponding to the operating current to the second operating current threshold, the method for controlling a compressor further includes: setting a current threshold value as a first working current threshold value on the basis of the condition that the bus voltage is greater than a third bus voltage threshold value; wherein the third bus voltage threshold is greater than the second bus voltage threshold.
In the technical scheme, in order to avoid the situation that under the influence of power grid fluctuation, the bus voltage repeatedly fluctuates near the second bus voltage threshold value to cause frequent switching of the threshold value corresponding to the working current, after the step of adjusting the threshold value corresponding to the working current to the second current threshold value is executed when the bus voltage is lower than the second bus voltage threshold value, and the condition that the bus voltage is recovered to be larger than the third bus voltage threshold value is required to be met, the threshold value corresponding to the working current is recovered to the first current threshold value, so that the system operation pressure is reduced, and the algorithm stability and reliability are improved.
In any of the above solutions, the command signal includes a command current and a command voltage; the instruction current comprises a weak magnetic loop output value and a rotating speed loop output value of the compressor, and the instruction voltage comprises a d-axis current loop output value and a q-axis current loop output value of the compressor; the protection values comprise a weak magnetic loop output protection value, a rotating speed loop output protection value, a d-axis current loop output protection value and a q-axis current loop output protection value.
In the technical scheme, a flux weakening ring output value and a rotating speed ring output value fixed on the compressor are command current values, and a d-axis current ring output value and a q-axis current ring output value fixed on the compressor are command voltage values. Meanwhile, the output value of the weak magnetic loop, the output value of the rotating speed loop, the output value of the d-axis current loop and the output value of the q-axis current loop are provided with corresponding protection values which are recorded as the output protection value of the weak magnetic loop, the output protection value of the rotating speed loop, the output protection value of the d-axis current loop and the output protection value of the q-axis current loop.
The protection value of each instruction signal is a preset value and can be adjusted according to actual conditions.
In any of the above technical solutions, the step of adjusting the amplitude limit value of the instruction signal to be reduced to the protection value specifically includes: adjusting the amplitude limiting value of the output value of the weak magnetic ring to be reduced to the output protection value of the weak magnetic ring, and adjusting the amplitude limiting value of the output value of the rotating speed ring to be reduced to the output protection value of the rotating speed ring; and/or adjusting the amplitude limiting value of the output value of the d-axis current loop to be reduced to the output protection value of the d-axis current loop, and adjusting the output amplitude limiting value of the q-axis current loop to be reduced to the output protection value of the q-axis current loop.
In the technical scheme, when the working current rises to exceed a set current threshold (namely a first current threshold or a second current threshold), any one of a current command value (comprising a flux weakening ring output value and a rotating speed ring output value) and a voltage command value (comprising a d-axis current ring output value and a q-axis current ring output value) is adjusted, or the amplitude limiting values of the current command value and the voltage command value are adjusted to corresponding protection values at the same time, so that the frequency and the current of the compressor are effectively and quickly reduced, and overcurrent shutdown is prevented.
In any of the above technical solutions, after the step of adjusting the clipping value of the command signal to be reduced to the protection value, the control method further includes: based on the fact that the bus voltage is larger than the first bus voltage threshold value, after delaying for a preset time, gradually restoring the amplitude limiting value of the instruction signal to an initial value; wherein, the range of the preset duration is as follows: 30 seconds to 240 seconds.
According to the technical scheme, after the bus voltage is recovered to be larger than the first bus voltage threshold value, the amplitude limiting value of the instruction signal is gradually recovered to the initial value after a period of time is delayed, the situation that the bus voltage is reduced again due to power grid fluctuation is prevented by delaying the preset time length, and the amplitude limiting value is recovered to the initial value after the power grid recovers normal power supply is waited. Generally, if the bus voltage recovers to be greater than the first bus voltage threshold value and continues to stabilize for 30 seconds to 240 seconds, the grid can be considered to recover normal power supply.
When the amplitude limiting value of the instruction signal is restored to the initial value, the current of the compressor is correspondingly increased, and in order to prevent the current from being instantly increased to cause current impact, the amplitude limiting value of the instruction signal is gradually restored to the initial value after the preset time is delayed.
A second aspect of the present invention provides a control system of a compressor, including: a memory configured to store a computer program; the processor is configured to execute a computer program to implement the control method of the compressor provided in any of the above technical solutions, and therefore, the control system of the compressor includes all the beneficial effects of the control method of any of the above compressors, which is not described herein again.
A third aspect of the present invention provides a compressor assembly comprising: a compressor; according to the control system of the compressor provided in any one of the above technical solutions, the control system of the compressor is connected with the compressor and configured to control the operation of the compressor. Therefore, the compressor assembly includes all the advantages of the control system of the compressor in any of the above technical solutions, which are not described herein again.
A fourth aspect of the present invention provides an air conditioning apparatus comprising: a heat exchanger assembly; in any of the above embodiments, the compressor assembly is connected to the heat exchanger assembly. Therefore, the air conditioning equipment comprises all the advantages of the compressor assembly provided in any one of the above technical solutions, and details are not repeated herein.
A fifth aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to implement the method for controlling a compressor provided in any one of the above technical solutions, and therefore, the computer-readable storage medium includes all the advantages of the method for controlling a compressor provided in any one of the above technical solutions, which are not described herein again.
Detailed Description
In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.
A control method of a compressor, a control system of a compressor, a compressor assembly, an air conditioner, and a computer-readable storage medium according to some embodiments of the present invention are described below with reference to fig. 1 to 13.
The first embodiment is as follows:
as shown in fig. 1, in an embodiment of the first aspect of the present invention, there is provided a control method of a compressor, including:
s102, acquiring bus voltage of a power supply line of the compressor, and acquiring working current of the compressor;
and S104, adjusting the amplitude limiting value of the command signal of the compressor according to the bus voltage and the working current.
In an embodiment, as shown in fig. 2, the step of adjusting the command signal threshold of the compressor according to the bus voltage and the working current specifically includes:
s202, on the basis that the bus voltage is smaller than a first bus voltage threshold value and the bus voltage is larger than a second bus voltage threshold value, adjusting a current threshold value corresponding to the working current to be a first working current threshold value;
and S204, if the working current is larger than the first working current threshold, reducing the amplitude limiting value of the adjustment instruction signal to a protection value.
In some embodiments, as shown in fig. 3, the step of adjusting the command signal threshold of the compressor according to the bus voltage and the working current further includes:
s302, on the basis that the bus voltage is smaller than the second bus voltage threshold, adjusting the current threshold corresponding to the working current to be the second working current threshold;
and S304, if the working current is larger than the second working current threshold, the threshold is adjusted to be reduced to a protection value.
Wherein the second operating current threshold is less than the first operating current threshold.
In some embodiments, after the step of adjusting the current threshold corresponding to the operating current to the second operating current threshold, the control method of the compressor further includes: setting a current threshold value as a first working current threshold value on the basis of the condition that the bus voltage is greater than a third bus voltage threshold value; wherein the third bus voltage threshold is greater than the second bus voltage threshold.
In some embodiments, the command signal includes a command current and a command voltage; the instruction current comprises a weak magnetic loop output value and a rotating speed loop output value of the compressor, and the instruction voltage comprises a d-axis current loop output value and a q-axis current loop output value of the compressor; the protection values comprise a weak magnetic loop output protection value, a rotating speed loop output protection value, a d-axis current loop output protection value and a q-axis current loop output protection value.
In some embodiments, the step of reducing the amplitude limit value of the integer instruction signal to the protection value specifically includes: adjusting the amplitude limiting value of the output value of the weak magnetic ring to be reduced to the output protection value of the weak magnetic ring, and adjusting the amplitude limiting value of the output value of the rotating speed ring to be reduced to the output protection value of the rotating speed ring; and/or adjusting the amplitude limiting value of the output value of the d-axis current loop to be reduced to the output protection value of the d-axis current loop, and adjusting the output amplitude limiting value of the q-axis current loop to be reduced to the output protection value of the q-axis current loop.
In some embodiments, after the step of adjusting the clipping value of the command signal to decrease to the guard value, the control method further includes: based on the fact that the bus voltage is larger than the first bus voltage threshold value, after delaying for a preset time, gradually restoring the amplitude limiting value of the instruction signal to an initial value; wherein, the range of the preset duration is as follows: 30 seconds to 240 seconds.
In the embodiments provided by the present invention, on the one hand, the bus voltage and the working current of the compressor are used as trigger conditions, so that the grid fluctuation can be responded to more quickly. On the other hand, when the power grid fluctuates, the amplitude limiting value of the instruction signal is adjusted to reduce the frequency and the current of the compressor, so that the response speed is high, and compared with a mode of issuing a frequency limiting instruction through a controller, the frequency and the current of the compressor can be reduced more quickly, and overcurrent shutdown is effectively avoided.
Specifically, a flux weakening loop output value and a rotation speed loop output value fixed to the compressor are command current values, and a d-axis current loop output value and a q-axis current loop output value fixed to the compressor are command voltage values. Meanwhile, the output value of the weak magnetic loop, the output value of the rotating speed loop, the output value of the d-axis current loop and the output value of the q-axis current loop are provided with corresponding protection values which are recorded as the output protection value of the weak magnetic loop, the output protection value of the rotating speed loop, the output protection value of the d-axis current loop and the output protection value of the q-axis current loop.
When the working current rises to exceed a set current threshold (namely a first current threshold or a second current threshold), any one of a current instruction value (comprising a flux weakening ring output value and a rotating speed ring output value) and a voltage instruction value (comprising a d-axis current ring output value and a q-axis current ring output value) is adjusted, or the amplitude limiting values of the current instruction value and the voltage instruction value are adjusted to corresponding protection values at the same time, so that the frequency and the current of the compressor are effectively and quickly reduced, and overcurrent shutdown is prevented.
The protection value of each instruction signal is a preset value and can be adjusted according to actual conditions.
In a specific control process, if the bus voltage is smaller than a first bus voltage threshold value but larger than a second bus voltage threshold value, it is indicated that the current bus voltage has a tendency to drop and a risk of overcurrent shutdown exists, at this time, a current threshold value corresponding to the working current is adjusted to be a first current threshold value, the first current threshold value is lower than a current threshold value corresponding to the overcurrent shutdown, and when the working current is larger than or lower than the working current threshold value, the amplitude limiting value of the instruction signal of the compressor is reduced.
And when the bus voltage is reduced to be smaller than the second bus voltage threshold value, the current power grid fluctuation is large, and the bus voltage reduction amplitude is large. At this time, the current threshold corresponding to the working current is adjusted to be the second working current threshold, and the second working current threshold is smaller than the first working current threshold, namely, the step of reducing the instruction signal threshold is triggered earlier, so that the response speed of frequency reduction and current limiting is further improved.
In order to avoid the situation that the bus voltage repeatedly fluctuates near the second bus voltage threshold value under the influence of power grid fluctuation, so that the threshold value corresponding to the working current is frequently switched, when the bus voltage is lower than the second bus voltage threshold value, and after the step of adjusting the threshold value corresponding to the working current to the second current threshold value is executed, and the condition that the bus voltage is recovered to be larger than the third bus voltage threshold value needs to be met, the threshold value corresponding to the working current is recovered to the first current threshold value, so that the system operation pressure is reduced, and the algorithm stability and reliability are improved.
When the bus voltage is recovered to be larger than the first bus voltage threshold value, delaying for a period of time, gradually recovering the amplitude limiting value of the instruction signal to the initial value, preventing the bus voltage from being reduced again due to power grid fluctuation by delaying for a preset time, and recovering the amplitude limiting value to the initial value after the power grid recovers to be normally powered.
Generally, if the bus voltage recovers to be greater than the first bus voltage threshold value and continues to stabilize for 30 seconds to 240 seconds, the grid can be considered to recover normal power supply. When the amplitude limiting value of the instruction signal is restored to the initial value, the current of the compressor is correspondingly increased, and in order to prevent the current from being instantly increased to cause current impact, the amplitude limiting value of the instruction signal is gradually restored to the initial value after the preset time is delayed.
The embodiment of the invention directly pulls the frequency and the current of the compressor by adjusting the amplitude limiting value of the instruction signal of the compressor, avoids the failure of current limiting caused by insufficient frequency limiting, has higher response speed (millisecond level), effectively reduces the condition of overcurrent shutdown caused by power grid fluctuation, improves the operation reliability of the compressor, and ensures the operation effect and the user experience of the compressor.
Example two:
in one embodiment of the present invention, the following are specific:
firstly, defining the output values of the weak magnetic ring and the rotating speed ring as command currents, and limiting values of the command currents are IdLim and IqLim respectively. The output values of the d-axis current loop and the q-axis current loop are defined as command voltages, and the limiting values are VdLim and VqLim respectively.
Specifically, the positions of the clipped values of the command current or the command voltage in the entire algorithm are shown in fig. 4 and 5, respectively.
When the grid voltage drops to cause the bus voltage Vdc to drop, specifically to be lower than the first voltage threshold, but Vdc does not drop below the set drop threshold (i.e. the second voltage threshold) VdcFall, a down-conversion trigger value is set, that is, the threshold corresponding to the running current is Imax1, and at this time, if the running frequency of the compressor is kept unchanged (especially, high frequency), the phase current thereof will be rapidly increased. When the compressor working current value Icomp is detected to exceed Imax1(Imax1 is smaller than the hardware overcurrent protection value Ioc of the compressor and larger than the maximum current of the normal operation of the compressor), the amplitude limiting value of the command current or the command voltage is reduced, and the current of the compressor is instantly reduced at the moment.
When the grid voltage sag causes the bus voltage Vdc to drop and to be less than the sag threshold VdcFall, the down-trigger value is set to Imax2, and Imax2< Imax 1.
When it is detected that the compressor operating current value Icomp exceeds Imax2, the clip value of the command current or command voltage is also reduced, at which point the compressor will trigger a down-current earlier to avoid an over-current shutdown (low voltage protection if the bus voltage drops too low).
In order to avoid repeated switching of the down-conversion trigger value caused by the fact that Vdc fluctuates back and forth near the drop threshold value VdcFall, a voltage return difference is added, and a third voltage threshold value, namely a recovery threshold value VdcRecovery, is met if the recovery threshold value VdcRecovery is exceeded after Vdc drops and recovers again:
VdcRecovery > VdcFall, the down-trigger value is restored to Imax 1.
After the limited value of the command current or the command voltage is kept at a small value for a period of time, the limited value is gradually and gradually restored to the initial value in an increasing way (the increasing restoration is adopted to prevent the current impact). If the voltage drop occurs during the increment process or after the initial value is recovered, the control logic is repeatedly executed.
Specifically, the control logic is shown in FIG. 6:
s602, detecting the working current value Icomp and the bus voltage value Vdc of the compressor in real time;
s604, judging whether Vdc falls below VdcFall; if yes, entering S610, otherwise entering S608;
s606, judging whether Vdc is recovered to be more than Vdcrecovery; if yes, entering S608, otherwise, entering S610;
s608, judging whether Icomp is larger than Imax 1; if yes, the process goes to S612, otherwise, the process returns to S602;
s610, judging whether Icomp is larger than Imax 2; if yes, the process goes to S612, otherwise, the process returns to S602;
s612, reducing the amplitude limit value of the command current and/or the command voltage to a protection value;
and S614, after delaying the preset time, gradually and gradually restoring the amplitude limiting value of the instruction voltage or the instruction current to the initial value.
Example three:
in an embodiment of the present invention, the description is given by taking the command signal as the command current, specifically as follows:
the voltage of the power grid is reduced to 180V within 2s from 220V, and is restored to 220V within 2s after 10 s.
If only the master control limited frequency includes logic, that is, the master control limited frequency does not respond yet, and the compressor current continuously increases until the compressor is shut down by overcurrent, as shown in fig. 7.
Where channel 1 is the compressor current, channel 2 is the bus voltage, and channel 4 is the input supply voltage.
When the control method of the compressor provided by the invention is adopted, when the working current value of the compressor exceeds the trigger value 40A, the instruction current amplitude limit value is immediately reduced, at the moment, the frequency and the current of the compressor are instantly reduced, and particularly, as shown in figure 8, at the moment, the compressor is not in overcurrent shutdown.
After a period of time, the instruction current amplitude limiting value is gradually increased to an initial value, and the frequency of the compressor is gradually restored to the initial frequency in the increasing process. Thereby effectively avoiding the occurrence of overcurrent shutdown.
Example four:
in an embodiment of the present invention, the description is given by taking the command signal as the command current, specifically as follows:
in this embodiment, the second voltage threshold, i.e., the droop threshold VdcFall, is set to 400V, the third voltage threshold, i.e., the recovery threshold VdcRecovery, is set to 430V, the first current threshold Imax1 is set to 42A, and the second current threshold Imax2 is set to 35A.
It is understood that the threshold parameter can be freely set according to actual requirements, and is not limited to the above value.
The first condition is as follows:
as shown in fig. 9, the grid voltage drops from 220V to 200V instantly, and recovers to 220V instantly after 5s, in the process, Vdc drops from 514V to 466V suddenly, and is greater than a drop threshold value VdcFall, and Imax1 is used as a trigger value.
As shown in fig. 9, after the compressor current rapidly increases beyond Imax1 after the voltage drop, the command current limit value is immediately decreased, at this time, the compressor frequency and current are both instantaneously decreased, and no overcurrent shutdown occurs.
Case two:
as shown in fig. 10, the grid voltage is instantaneously reduced from 220V to 160V, and then instantaneously returns to 220V after 7s, and in the process, Vdc is suddenly reduced from 514V to 370V, which is smaller than the drop threshold VdcFall. If a large Imax1 is still used as the trigger, there is still the possibility of an overcurrent shutdown after the compressor current increases rapidly beyond Imax1 after the voltage dip because Vdc is low and the compressor current is high, the system stability is poor.
Case three:
as shown in fig. 11 and 12, the grid voltage is instantaneously reduced from 220V to 160V, and is instantaneously restored to 220V after 200ms, in the process, Vdc is suddenly reduced from 514V to 372V, which is smaller than a drop threshold VdcFall, and a small Imax2 is used as a trigger value. As shown in fig. 11, the compressor current is already greater than Imax2 before the voltage dip, so when Vdc is less than VdcFall immediately before down protection is triggered, both the compressor frequency and current are momentarily reduced to avoid an over-current shutdown.
After 60s, the command current limit value is gradually increased to the initial value, and the compressor frequency and the current are gradually increased in the increasing process, as shown in fig. 12.
From the above, it can be seen that the system stability has a large relationship with the amount of Vdc drop and the setting of the down-trigger value Imax. The more Vdc falls, the less stable the system. And the smaller the down-conversion trigger value Imax is set, the better the system stability is. Therefore, the control mode that the down-conversion trigger value Imax is subjected to sectional value taking according to the size of Vdc is beneficial to improving the stability of the system.
Example five:
as shown in fig. 13, in one embodiment of the present invention, there is provided a control system 1300 of a compressor, including: a memory 1302 and a processor 1304; the memory 1302 is configured to store a computer program; the processor 1304 is configured to execute a computer program to implement the control method of the compressor provided in any of the above embodiments, and therefore, the control system of the compressor includes all the advantages of the control method of any of the above compressors, which will not be described herein again.
Example six:
in one embodiment of the present invention, there is provided a compressor assembly including: a compressor; the control system for a compressor as provided in any of the above embodiments, the control system for a compressor is connected to the compressor and configured to control the operation of the compressor. Therefore, the overall advantages of the control system of the compressor including the compressor in any of the above embodiments will not be described herein.
Example seven:
in one embodiment of the present invention, there is provided an air conditioning apparatus including: a heat exchanger assembly; as provided in any of the embodiments above, the compressor assembly is coupled to the heat exchanger assembly. Therefore, the air conditioning apparatus includes all the advantages of the compressor assembly provided in any one of the above embodiments, which are not described herein again.
Example eight:
in an embodiment of the present invention, a computer-readable storage medium is provided, on which a computer program is stored, and the computer program is executed by a processor to implement the control method of the compressor provided in any of the above embodiments, so that the computer-readable storage medium includes all the advantages of the control method of the compressor provided in any of the above embodiments, and the details are not repeated herein.
In the description of the present invention, the terms "plurality" or "a plurality" refer to two or more, and unless otherwise specifically defined, the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention; the terms "connected," "mounted," "secured," and the like are to be construed broadly and include, for example, fixed connections, removable connections, or integral connections; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the description of the present invention, the description of the terms "one embodiment," "some embodiments," "specific embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In the present invention, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.