CN114294781B - Compressor protection method and device, air conditioning unit and storage medium - Google Patents
Compressor protection method and device, air conditioning unit and storage medium Download PDFInfo
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- CN114294781B CN114294781B CN202111592355.0A CN202111592355A CN114294781B CN 114294781 B CN114294781 B CN 114294781B CN 202111592355 A CN202111592355 A CN 202111592355A CN 114294781 B CN114294781 B CN 114294781B
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Abstract
The invention discloses a protection method and a protection device for a compressor, an air conditioning unit and a storage medium, wherein the method comprises the following steps: under the condition that the compressor operates according to the current operation state, phase current of a motor in the compressor is obtained; determining whether phase current of the motor fluctuates; if the phase current of the motor is determined to fluctuate, determining that the current running state of the compressor is abnormal; and under the condition that the current running state of the compressor is abnormal, triggering a preset abnormal protection mechanism to control the compressor to stop. According to the scheme, whether the compressor normally operates is judged by monitoring the phase current of the compressor, and shutdown protection is applied in time when the abnormal operation of the compressor is determined, so that the service life of the compressor is prolonged.
Description
Technical Field
The invention belongs to the technical field of air conditioners, and particularly relates to a method and a device for protecting a compressor, an air conditioning unit and a storage medium, in particular to a method and a device for protecting the abnormal operation of the compressor of the air conditioning unit (such as a condensing unit), the air conditioning unit and the storage medium.
Background
In a related scheme, a rotor type compressor drives a built-in protective measure, and overvoltage protection and low-voltage protection are provided for the high and low of bus voltage; aiming at the magnitude of the phase current of the compressor, overcurrent protection and undercurrent protection are provided; the normal operation of the compressor is subjected to step-out protection, open-phase protection, IPM (intelligent power module) temperature protection and the like. In some cases, when the load end of the compressor is abnormal, such as oil shortage, liquid carrying and the like, the compressor is unstable in operation, and the rotating speed and the current fluctuate, but the current existing protective measures cannot monitor the abnormality; when the compressor runs in an abnormal state for a long time, the mechanical structure of the compressor is seriously abraded, and the service life of the compressor is influenced.
The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.
Disclosure of Invention
The invention aims to provide a protection method and a protection device for a compressor, an air conditioning unit and a storage medium, which aim to solve the problem that when the compressor runs, the compressor is in an abnormal state such as oil shortage and liquid carrying at a load end of the compressor, if the compressor runs for a long time in the abnormal state, the mechanical structure of the compressor is abraded, and the service life of the compressor is influenced, and the effects of judging whether the compressor runs normally by monitoring phase current of the compressor, applying shutdown protection in time when the abnormal operation of the compressor is determined, avoiding the abrasion of the mechanical structure of the compressor caused by the long-time running of the compressor in the abnormal state, and being beneficial to prolonging the service life of the compressor are achieved.
The invention provides a protection method of a compressor, which comprises the following steps: under the condition that the compressor operates according to the current operation state, phase current of a motor in the compressor is obtained; determining whether phase current of the motor fluctuates; if the phase current of the motor is determined to fluctuate, determining that the current running state of the compressor is abnormal; and under the condition that the current running state of the compressor is abnormal, triggering a preset abnormal protection mechanism to control the compressor to stop.
In some embodiments, determining whether phase current of the electric machine fluctuates comprises: determining a calculated value of the phase current of the motor, and recording the calculated value as the calculated phase current; determining whether the calculated phase current of the motor is greater than or equal to a set current threshold; and if the calculated phase current of the motor is determined to be larger than or equal to the current threshold, determining that the phase current of the motor fluctuates.
In some embodiments, determining a calculated value of phase current for the motor, denoted as calculated phase current, comprises: determining an effective value of the phase current of the motor, and recording the effective value as the effective phase current of the motor; filtering the effective phase current of the motor to obtain a filtering current value, and recording the filtering current value as the filtering phase current of the motor; filtering phase currents of the motor, corresponding to the phase currents of the motor, sampled at different sampling points in a set sampling period, form a filtering phase current sequence; determining a maximum filtering phase current and a minimum filtering phase current in the filtering current sequence; and determining the difference value of the maximum filtering phase current and the minimum filtering phase current as the calculated value of the phase current of the motor, and recording the calculated value as the calculated phase current.
In some embodiments, determining whether phase current of the motor fluctuates further comprises: after determining that the calculated phase current of the motor is larger than or equal to the current threshold value and before determining that the phase current of the motor fluctuates, determining whether the times that the calculated phase current of the motor is larger than or equal to the current threshold value is larger than or equal to the set times continuously occur within the set calculation time; wherein, every time the calculated phase current of the motor is determined to be greater than or equal to the current threshold value once, adding 1 to the number of times that the calculated phase current of the motor is greater than or equal to the current threshold value; if the condition that the frequency that the calculated phase current of the motor is larger than or equal to the current threshold value is larger than or equal to the set frequency is determined to continuously appear, determining that the phase current of the motor fluctuates; and if the condition that the frequency that the calculated phase current of the motor is larger than or equal to the current threshold value is smaller than the set frequency is determined to continuously occur, re-determining the calculated value of the phase current of the motor.
In some embodiments, triggering a preset exception protection mechanism includes: and stopping the output of the PWM signal of the motor in the compressor, and initiating a warning message for protecting the compressor when the current running state of the compressor is abnormal.
In accordance with the above method, another aspect of the present invention provides a protection apparatus for a compressor, comprising: an obtaining unit configured to obtain a phase current of a motor in the compressor in a case where the compressor is operated in a current operation state; a control unit configured to determine whether a phase current of the motor fluctuates; the control unit is further configured to determine that the current operation state of the compressor is abnormal if it is determined that the phase current of the motor fluctuates; the control unit is further configured to trigger a preset abnormal protection mechanism to control the compressor to stop when the current operation state of the compressor is abnormal.
In some embodiments, the control unit, determining whether phase current of the motor fluctuates, comprises: determining a calculated value of the phase current of the motor, and recording the calculated value as the calculated phase current; determining whether the calculated phase current of the motor is greater than or equal to a set current threshold; and if the calculated phase current of the motor is determined to be larger than or equal to the current threshold, determining that the phase current of the motor fluctuates.
In some embodiments, the control unit, determining a calculated value of phase current of the motor, noted as calculated phase current, comprises: determining an effective value of the phase current of the motor, and recording the effective value as the effective phase current of the motor; filtering the effective phase current of the motor to obtain a filtering current value which is recorded as the filtering phase current of the motor; filtering phase currents of the motor, corresponding to the phase currents of the motor, sampled at different sampling points in a set sampling period, form a filtering phase current sequence; determining a maximum filtering phase current and a minimum filtering phase current in the filtering current sequence; and determining the difference value of the maximum filtering phase current and the minimum filtering phase current as the calculated value of the phase current of the motor, and recording the calculated value as the calculated phase current.
In some embodiments, the control unit, determining whether phase current of the motor fluctuates, further comprises: after determining that the calculated phase current of the motor is greater than or equal to the current threshold value and before determining that the phase current of the motor fluctuates, determining whether the situation that the frequency that the calculated phase current of the motor is greater than or equal to the current threshold value is greater than or equal to the set frequency continuously occurs within the set calculation time; wherein, every time the calculated phase current of the motor is determined to be greater than or equal to the current threshold value once, adding 1 to the number of times that the calculated phase current of the motor is greater than or equal to the current threshold value; if the condition that the frequency that the calculated phase current of the motor is larger than or equal to the current threshold value is larger than or equal to the set frequency is determined to continuously appear, determining that the phase current of the motor fluctuates; and if the condition that the frequency that the calculated phase current of the motor is larger than or equal to the current threshold value is smaller than the set frequency is determined to continuously occur, re-determining the calculated value of the phase current of the motor.
In some embodiments, the control unit, triggering a preset exception protection mechanism, includes: and stopping the output of the PWM signal of the motor in the compressor, and initiating a warning message for protecting the compressor when the current running state of the compressor is abnormal.
In accordance with another aspect of the present invention, there is provided an air conditioning unit, comprising: the protection device of the compressor is described above.
In line with the above method, a further aspect of the present invention provides a storage medium, which includes a stored program, wherein when the program runs, the apparatus where the storage medium is located is controlled to execute the above protection method for a compressor.
Therefore, according to the scheme of the invention, a compressor abnormal operation monitoring mechanism is added in a control mechanism of the compressor to monitor the phase current of the motor in the compressor and determine whether the phase current of the motor has large fluctuation or not, so that the abnormal operation of the compressor is determined under the condition that the phase current of the motor has large fluctuation, and the compressor is controlled to stop in time under the condition that the abnormal operation of the compressor is determined, therefore, the normal operation of the compressor is judged by monitoring the phase current of the compressor, the stop protection is applied in time when the abnormal operation of the compressor is determined, the abrasion of the mechanical structure of the compressor caused by the long-time operation of the compressor under the abnormal state is avoided, and the service life of the compressor is prolonged.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is a schematic flow diagram illustrating an embodiment of a compressor protection method according to the present invention;
FIG. 2 is a schematic flow chart illustrating one embodiment of determining whether phase current of the motor fluctuates in the method of the present invention;
FIG. 3 is a schematic flow chart diagram illustrating one embodiment of the method of the present invention for determining calculated values of phase currents for the motor;
FIG. 4 is a flowchart illustrating an embodiment of repeatedly determining a set number of times in the method of the present invention;
FIG. 5 is a schematic structural diagram of an embodiment of a protection device for a compressor according to the present invention;
fig. 6 is a flowchart illustrating an embodiment of a method for determining an abnormal operation state of a compressor.
The reference numbers in the embodiments of the present invention are as follows, in combination with the accompanying drawings:
102-an obtaining unit; 104-determination unit.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the disclosed embodiments are merely exemplary of the invention, and are not intended to be exhaustive or exhaustive. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a protection measure for abnormal operation of a compressor, in particular a protection measure for abnormal operation of a compressor of a condensing unit, such as a protection method of the compressor, in order to cope with the condition that the compressor is abnormally operated and damaged due to the instability (oil shortage, liquid carrying and the like) of the size of a load end when the compressor is operated and mainly solve the problem that the compressor is abnormally operated due to the instability (oil shortage, liquid carrying) of the size of the load end when the compressor is operated.
According to an embodiment of the present invention, a method for protecting a compressor is provided, as shown in fig. 1, which is a schematic flow chart of an embodiment of the method of the present invention. The protection method of the compressor may include: step S110 to step S140.
In step S110, in the case where the compressor is operated in the current operation state, phase currents of a motor in the compressor are acquired.
At step S120, it is determined whether phase current of the motor fluctuates.
In some embodiments, a specific process of determining whether the phase current of the motor fluctuates in step S120 is further described with reference to a flowchart of an example of determining whether the phase current of the motor fluctuates in the method of the present invention shown in fig. 2, which includes: step S210 to step S230.
And step S210, determining a calculated value of the phase current of the motor, and recording the calculated value as the calculated phase current.
In some embodiments, the calculated value of the phase current of the motor is determined in step S210, and is recorded as a specific process of calculating the phase current, which can be seen in the following exemplary descriptions.
The following further describes a specific process of determining the calculated value of the phase current of the motor in step S210 with reference to a flowchart of an embodiment of determining the calculated value of the phase current of the motor in the method of the present invention shown in fig. 3, including: step S310 to step S350.
Step S310, determining an effective value of the phase current for the motor, and recording the effective value as the effective phase current of the motor.
Step S320, performing filtering processing on the effective phase current of the motor, for example, performing low-pass filtering processing on the phase current of the motor, to obtain a filtered current value, which is recorded as the filtered phase current of the motor.
And step S330, filtering phase currents of the motor corresponding to the phase currents of the motor sampled at different sampling points in a set sampling period form a filtering phase current sequence.
Step S340, determining a maximum filtering phase current and a minimum filtering phase current in the filtering current sequence.
Step S350, determining the difference between the maximum filtered phase current and the minimum filtered phase current as a calculated value of the phase current of the motor, and recording the calculated value as a calculated phase current.
In the scheme of the invention, the phase current is monitored in real time to judge whether the current value has large fluctuation, specifically, the collected current value is filtered firstly, then the maximum value and the minimum value of the effective value of the current in unit time are judged, if the difference value between the maximum value and the minimum value is large and is repeated for a plurality of times continuously, the judgment is that the phase current has fluctuation, and the load end of the compressor has abnormity.
Step S220, determining whether the calculated phase current of the motor is greater than or equal to a set current threshold.
In step S230, if it is determined that the calculated phase current of the motor is greater than or equal to the current threshold, it is determined that the phase current of the motor fluctuates. If the calculated phase current of the motor is smaller than the current threshold, the phase current of the motor in the compressor is obtained again under the condition that the compressor operates according to the current operation state, so that whether the obtained phase current of the motor fluctuates or not is determined.
In the scheme of the invention, whether the current value has large fluctuation or not is judged by adding a compressor abnormal operation monitoring mechanism, particularly by monitoring the phase current in real time. If the current value has large fluctuation, the compressor load end is judged to be abnormal, and at the moment, a compressor abnormal operation protection mechanism is executed, for example, the output of a PWM (pulse width modulation) signal of a motor in the compressor is closed, so that the compressor is stopped.
In some embodiments, the determining whether the phase current of the motor fluctuates in step S120 further includes: the process of determining the set number of times is repeated.
The following further describes a specific process of repeatedly determining the set number in step S120, with reference to a flowchart of an embodiment of repeatedly determining the set number in the method of the present invention shown in fig. 4, including: step S410 to step S430.
And step S410, after the calculated phase current of the motor is determined to be larger than or equal to the current threshold value and before the phase current of the motor is determined to fluctuate, whether the situation that the frequency that the calculated phase current of the motor is larger than or equal to the current threshold value is larger than or equal to the set frequency continuously occurs is determined within the set calculation time. And adding 1 to the number of times that the calculated phase current of the motor is greater than or equal to the current threshold value every time that the calculated phase current of the motor is determined to be greater than or equal to the current threshold value once.
Step S420, if it is determined that the number of times that the calculated phase current of the motor is greater than or equal to the current threshold is greater than or equal to the set number of times, it is determined that the phase current of the motor fluctuates.
And step S430, if the condition that the frequency that the calculated phase current of the motor is larger than or equal to the current threshold value is smaller than the set frequency is determined to continuously occur, re-determining the calculated value of the phase current of the motor.
Fig. 6 is a flowchart illustrating an embodiment of a method for determining an abnormal operation state of a compressor.
And step 1, controlling the compressor to operate.
And 2, considering that the effective value of the phase current of the compressor can fluctuate due to the instability of the load when the compressor operates abnormally, and the specific waveform is similar to a sawtooth wave which changes at the peak value. Therefore, under the condition that the compressor is running, the phase current value of the motor in the compressor is acquired, specifically, the controller (such as a CPU) samples the phase current, and calculates to obtain an effective value of the current sampled current (i.e., the sampled phase current value). Where the effective value is equal to the current value divided by the root 2.
The phase current is sampled, specifically, current is collected through a resistance sampling network, a current signal is converted into a voltage signal, and the voltage signal is a current value collected through an ADC module in a CPU.
Step 3, in order to make the subsequent data processing and the judgment of the current waveform more accurate, the current sampling is carried outThe effective value of the current is subjected to low-pass filtering, and current sampling points acquired in unit sampling time after the low-pass filtering can be represented as a sequence i (x) = { i = i = 1 ，i 2 ，…，i n }。i 1 ，i 2 ，…，i n And the effective value of the current sampling current of each sampling point is represented by a value after low-pass filtering processing.
The low-pass filtering processing is performed on the effective value of the current sampling current, and specifically may be: in the program, a discretized low-pass filtering algorithm is set. The implementation process of the discretization low-pass filtering algorithm comprises the following steps: the current value at this moment after filtering is equal to: after the current value collected at present is multiplied by the filter coefficient, the current value filtered at the previous moment is subtracted and multiplied by the filter coefficient, and then the current value filtered at the previous moment is added. Is formulated as follows:
I(n)＝i(n)*k-k*I(n-1)+I(n-1)。
wherein, I (n) is a filtered current value to be calculated at n moments, I (n) is a current value to be processed currently, i.e. a collected value, I (n-1) is a filtered current value at the last moment, and k is a filter coefficient.
Step 4, in the sampling period time, using a bubbling sequencing method to find out the maximum value i (x) of the current effective value max Minimum value of current effective value i (x) min And the maximum value i (x) of the effective value of the current is calculated max Minimum value of current effective value i (x) min Comparing to obtain the difference value delta i = the maximum value i (x) of the current effective value max Minimum value of current effective value i (x) min 。
The bubble sorting method comprises the following implementation processes: the first value of the sequence is compared with the second value for the first time within a sequence, and if the first value is greater than the second value, the sequence is switched. Otherwise the sequence remains the same. The second value is compared with the third value after completion. By analogy, the maximum value in the last sequence appears at the last bit of the queue, and the maximum value can be found. The method for finding the minimum value is similar to the method for finding the minimum value, the sizes of the two values are compared, the smaller value is placed at the back position, and the like.
Wherein the current threshold value I TH The size of (2) is required to be set according to the power, the running frequency, the working condition and the like of the compressor. The higher the power, the higher the operating frequency, the current threshold I TH The larger the setting.
For example: the current value of the compressor with large power during operation is also large, and the fluctuation range of normal operation is also smaller, so that the power compressor needs to be slightly larger, and therefore a larger threshold value range needs to be provided for judging the fluctuation of the current value under the abnormal working condition. When the current value increases as the operating frequency increases, the current itself may fluctuate regularly at a high operating frequency, and therefore the determination threshold may be increased. Similarly, when the temperature is higher, the load of the compressor is large and the current is increased.
Step 6, if the difference value delta I is larger than or equal to the set current threshold I TH If the current is judged to have large fluctuation, the compressor is abnormally operated, and one condition judgment is met.
In order to avoid the contingency of single judgment, the judgment needs to be continuously performed for 5 times, and the difference value delta I is more than or equal to the current threshold I TH The current can be judged to have rapid fluctuation.
Step 7, if the difference value delta i<Set current threshold I TH The current can be judged to be stable at the moment, and the compressor is in a normal running state. In particular, at the difference Δ i<Set current threshold I TH In the case of (2), the count value count is cleared (even if the count value count = 0), and the process returns to step 2.
At step S130, if it is determined that the phase current of the motor fluctuates, it is determined that the current operation state of the compressor is abnormal.
In step S140, in case that an abnormality occurs in the current operation state of the compressor, a preset abnormality protection mechanism is triggered to control the compressor to stop.
According to the scheme provided by the invention, whether the compressor is in abnormal operation at present is judged by monitoring the change rule of the phase current, the abnormal condition is monitored and shutdown protection is applied by monitoring the magnitude of the phase current of the compressor, the abrasion of the mechanical structure of the compressor caused by long-time operation of the compressor in an abnormal state is avoided, and the service life of the compressor is prolonged.
In some embodiments, the triggering of the preset exception protection mechanism in step S140 includes: and stopping the output of the PWM signal of the motor in the compressor, and initiating a warning message for protecting the compressor when the current running state of the compressor is abnormal.
Referring to the example shown in FIG. 6, in step 6, if the difference Δ I ≧ the current threshold I is satisfied for 5 consecutive occurrences TH If so, immediately triggering abnormal protection, executing compressor protection, for example, closing PWM output, and reporting abnormal operation of the compressor for protection.
According to the scheme of the invention, on the premise of not adding any other modules and sensors, the phase current of the compressor is monitored and analyzed to judge whether the compressor normally operates, so that the accuracy is high, the monitoring speed is high, and no cost is increased.
By adopting the technical scheme of the embodiment, the abnormal operation monitoring mechanism of the compressor is added in the control mechanism of the compressor, the phase current of the motor in the compressor is monitored, whether the phase current of the motor is greatly fluctuated or not is determined, the abnormal operation of the compressor is determined under the condition that the phase current of the motor is greatly fluctuated, and the compressor is controlled to stop in time under the condition that the abnormal operation of the compressor is determined, so that whether the compressor normally operates or not is judged by monitoring the phase current of the compressor, the stop protection is applied in time when the abnormal operation of the compressor is determined, the abrasion of the mechanical structure of the compressor caused by the long-time operation of the compressor under the abnormal state is avoided, and the service life of the compressor is prolonged.
According to an embodiment of the present invention, there is also provided a protection apparatus of a compressor corresponding to the protection method of the compressor. Referring to fig. 5, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The protection apparatus of the compressor may include: an acquisition unit 102 and a control unit 104.
The obtaining unit 102 is configured to obtain a phase current of a motor in the compressor when the compressor is operated in the current operation state. The specific functions and processes of the acquiring unit 102 are referred to in step S110.
A control unit 104 configured to determine whether a phase current of the motor fluctuates. The specific function and processing of the control unit 104 are referred to in step S120.
In some embodiments, the control unit 104, determining whether phase current of the motor fluctuates, includes:
the control unit 104 is in particular further configured to determine a calculated value of the phase current of the motor, noted as calculated phase current. The specific functions and processes of the control unit 104 are also referred to in step S210.
In some embodiments, the control unit 104, determining a calculated value of the phase current of the motor, denoted as calculated phase current, includes:
the control unit 104 is further configured to determine an effective value of the phase current for the motor, denoted as effective phase current for the motor. The specific functions and processes of the control unit 104 are also referred to in step S310.
The control unit 104 is further specifically configured to perform filtering processing on the effective phase current of the motor, for example, perform low-pass filtering processing on the phase current of the motor, so as to obtain a filtered current value, which is recorded as the filtered phase current of the motor. The detailed function and processing of the control unit 104 are also referred to in step S320.
The control unit 104 is further specifically configured to form a filtered phase current sequence of the motor corresponding to the phase current of the motor sampled at different sampling points in a set sampling period. The specific functions and processes of the control unit 104 are also referred to in step S330.
The control unit 104 is in particular further configured to determine a maximum filtered phase current and a minimum filtered phase current in the sequence of filtered currents. The specific functions and processes of the control unit 104 are also referred to in step S340.
The control unit 104 is further configured to determine a difference between the maximum filtered phase current and the minimum filtered phase current as a calculated value of the phase current of the motor, which is recorded as the calculated phase current. The specific functions and processes of the control unit 104 are also referred to in step S350.
In the scheme of the invention, the phase current is monitored in real time to judge whether the current value has large fluctuation, specifically, the collected current value is filtered firstly, then the maximum value and the minimum value of the effective value of the current in unit time are judged, if the difference value between the maximum value and the minimum value is large and is repeated for a plurality of times continuously, the judgment is that the phase current has fluctuation, and the load end of the compressor has abnormity.
The control unit 104 is in particular further configured to determine whether the calculated phase current of the motor is greater than or equal to a set current threshold. The specific functions and processes of the control unit 104 are also referred to in step S220.
The control unit 104 is further configured to determine that a phase current of the motor fluctuates if it is determined that the calculated phase current of the motor is greater than or equal to the current threshold. If the calculated phase current of the motor is smaller than the current threshold, the phase current of the motor in the compressor is obtained again under the condition that the compressor operates according to the current operation state, so that whether the obtained phase current of the motor fluctuates or not is determined. The detailed function and processing of the control unit 104 are also referred to in step S220.
In the scheme of the invention, whether the current value has large fluctuation or not is judged by adding a compressor abnormal operation monitoring mechanism, particularly by monitoring the phase current in real time. If the current value has large fluctuation, the compressor load end is judged to be abnormal, and at the moment, a compressor abnormal operation protection mechanism is executed, for example, the output of a PWM (pulse width modulation) signal of a motor in the compressor is closed, so that the compressor is stopped.
In some embodiments, the control unit 104, determining whether a phase current of the motor fluctuates, further comprises:
the control unit 104 is specifically further configured to determine whether a situation that the number of times that the calculated phase current of the motor is greater than or equal to the current threshold value is greater than or equal to a set number of times continuously occurs within a set calculation time after determining that the calculated phase current of the motor is greater than or equal to the current threshold value and before determining that the phase current of the motor fluctuates. And adding 1 to the number of times that the calculated phase current of the motor is greater than or equal to the current threshold value every time that the calculated phase current of the motor is determined to be greater than or equal to the current threshold value once. The specific functions and processes of the control unit 104 are also referred to in step S610.
The control unit 104 is further specifically configured to determine that the phase current of the motor fluctuates if it is determined that the number of times that the calculated phase current of the motor is greater than or equal to the current threshold value is continuously greater than or equal to the set number of times. The specific functions and processes of the control unit 104 are also referred to in step S620.
The control unit 104 is further configured to, if it is determined that the number of times that the calculated phase current of the motor is greater than or equal to the current threshold value continuously occurs is less than the set number of times, re-determine the calculated value of the phase current of the motor. The specific function and processing of the control unit 104 are also referred to in step S630.
Fig. 6 is a flowchart illustrating an embodiment of an apparatus for determining an abnormal operation state of a compressor.
And step 1, controlling the compressor to operate.
And 2, considering that the effective value of the phase current of the compressor can fluctuate due to the instability of the load when the compressor operates abnormally, and the specific waveform is similar to a sawtooth wave which changes at the peak value. Therefore, under the condition that the compressor is running, the phase current value of the motor in the compressor is acquired, specifically, the controller (such as a CPU) samples the phase current, and calculates to obtain an effective value of the current sampled current (i.e., the sampled phase current value). Where the effective value is equal to the current value divided by the root 2.
Step 3, in order to make the subsequent data processing and the judgment of the current waveform more accurate, low-pass filtering is performed on the effective value of the current sampling current, and the current sampling points acquired in unit sampling time after the low-pass filtering can be represented as a sequence i (x) = { i = (i) = 1 ，i 2 ，…，i n }。i 1 ，i 2 ，…，i n And the effective value of the current sampling current of each sampling point is represented by a value after low-pass filtering processing.
The low-pass filtering processing is performed on the effective value of the current sampling current, and specifically may be: in the program, a discretized low-pass filtering algorithm is set. The implementation process of the discretization low-pass filtering algorithm comprises the following steps: the current value at this moment after filtering is equal to: after the current value collected at present is multiplied by the filter coefficient, the current value filtered at the previous moment is subtracted and multiplied by the filter coefficient, and then the current value filtered at the previous moment is added. Is formulated as follows:
I(n)＝i(n)*k-k*I(n-1)+I(n-1)。
wherein, I (n) is a filtered current value to be calculated at n moments, I (n) is a current value to be processed currently, i.e. a collected value, I (n-1) is a filtered current value at the last moment, and k is a filter coefficient.
Step 4, in the sampling period, using bubble sorting device to find out the maximum value i (x) of the current effective value max Minimum value of current effective value i (x) min And the maximum value i (x) of the effective value of the current is calculated max Minimum value of current effective value i (x) min Comparing to obtain the difference value delta i = the maximum value i (x) of the current effective value max Minimum value of current effective value i (x) min 。
The bubble sorting method comprises the following implementation processes: the first value of the sequence is compared with the second value for the first time within a sequence, and if the first value is greater than the second value, the sequence is switched. Otherwise the sequence remains the same. The second value is compared with the third value after completion. By analogy, the maximum value in the last sequence appears at the last bit of the queue, and the maximum value can be found. The device for finding the minimum value is similar to the device for finding the minimum value, the size of the front value and the size of the rear value are compared, the smaller value is placed at the rear position, and the rest is done in sequence.
Wherein the current threshold value I TH The size of (2) is required to be set according to the power, the running frequency, the working condition and the like of the compressor. The higher the power, the higher the operating frequency, the current threshold I TH The larger the setting.
For example: the current value of the compressor with large power can be large during operation, the fluctuation range of normal operation can be smaller, and the power compressor needs to be slightly larger, so that a larger threshold value range needs to be provided for judging the fluctuation of the current value under the abnormal working condition. When the current value increases as the operating frequency increases, the current itself may fluctuate regularly at a high operating frequency, and therefore the determination threshold may be increased. Similarly, when the temperature is higher, the load of the compressor is large and the current is increased.
Step 6, if the difference value delta I is larger than or equal to the set current threshold I TH If the current is judged to have large fluctuation, the compressor is abnormally operated, and one condition judgment is met.
In order to avoid the contingency of single judgment, the judgment needs to be continuously performed for 5 times, and the difference value delta I is more than or equal to the current threshold I TH The current can be judged to have rapid fluctuation.
Step 7, if the difference value delta i<Set current threshold I TH The current can be judged to be stable at the moment, and the compressor is in a normal running state. Specifically, at the difference Δ i<Set current threshold I TH In the case of (2), the count value count is cleared (even if the count value count = 0), and the process returns to step 2.
The control unit 104 is further configured to determine that the current operation state of the compressor is abnormal if it is determined that the phase current of the motor fluctuates. The specific function and processing of the control unit 104 are also referred to in step S130.
The control unit 104 is further configured to trigger a preset abnormal protection mechanism to control the compressor to stop when an abnormality occurs in the current operating state of the compressor. The specific function and processing of the control unit 104 are also referred to in step S140.
According to the scheme provided by the invention, whether the compressor is in abnormal operation at present is judged by monitoring the change rule of the phase current, the abnormal condition is monitored and shutdown protection is applied by monitoring the magnitude of the phase current of the compressor, the abrasion of the mechanical structure of the compressor caused by long-time operation of the compressor in an abnormal state is avoided, and the service life of the compressor is prolonged.
In some embodiments, the control unit 104, triggering a preset exception protection mechanism, includes: the control unit 104 is specifically configured to stop output of a PWM signal of a motor in the compressor, and initiate a warning message for protection when the current operation state of the compressor is abnormal.
Referring to the example shown in FIG. 6, in step 6, if the difference Δ I ≧ the current threshold I is satisfied for 5 consecutive occurrences TH If so, immediately triggering abnormal protection, executing compressor protection, for example, closing PWM output, and reporting abnormal operation of the compressor for protection.
According to the scheme of the invention, on the premise of not adding any other modules and sensors, the phase current of the compressor is monitored and analyzed to judge whether the compressor normally operates, so that the accuracy is high, the monitoring speed is high, and no cost is increased.
Since the processes and functions implemented by the apparatus of this embodiment substantially correspond to the embodiments, principles and examples of the method, reference may be made to the related descriptions in the embodiments without being detailed in the description of this embodiment, which is not described herein again.
By adopting the technical scheme of the invention, the abnormal operation monitoring mechanism of the compressor is added in the control mechanism of the compressor, the phase current of the motor in the compressor is monitored, whether the phase current of the motor has large fluctuation or not is determined, the abnormal operation of the compressor is determined under the condition that the phase current of the motor has large fluctuation, the compressor is controlled to stop in time under the condition that the abnormal operation of the compressor is determined, the monitoring speed is high, and the protection timeliness is good.
According to the embodiment of the invention, the air conditioning unit corresponding to the protection device of the compressor is also provided. The air conditioning unit may include: the protection device of the compressor is described above.
Since the processing and functions of the air conditioning unit of this embodiment are basically corresponding to the embodiments, principles and examples of the foregoing devices, reference may be made to the relevant description in the foregoing embodiments without being repeated in detail in the description of this embodiment.
By adopting the technical scheme of the invention, the abnormal operation monitoring mechanism of the compressor is added in the control mechanism of the compressor, the phase current of the motor in the compressor is monitored, whether the phase current of the motor has large fluctuation or not is determined, the abnormal operation of the compressor is determined under the condition that the phase current of the motor has large fluctuation, and the compressor is controlled to stop in time under the condition that the abnormal operation of the compressor is determined, so that the accuracy is high, and the cost is low.
According to an embodiment of the present invention, there is also provided a storage medium corresponding to a protection method of a compressor, the storage medium including a stored program, wherein when the program is executed, an apparatus in which the storage medium is located is controlled to perform the protection method of the compressor described above.
Since the processing and functions implemented by the storage medium of this embodiment substantially correspond to the embodiments, principles, and examples of the foregoing method, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.
By adopting the technical scheme of the invention, the abnormal operation monitoring mechanism of the compressor is added in the control mechanism of the compressor, the phase current of the motor in the compressor is monitored, whether the phase current of the motor has large fluctuation or not is determined, the abnormal operation of the compressor is determined under the condition that the phase current of the motor has large fluctuation, and the compressor is controlled to stop in time under the condition that the abnormal operation of the compressor is determined, so that the method is reliable and safe.
In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.
The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (8)
1. A method of protecting a compressor, comprising:
under the condition that the compressor operates according to the current operation state, phase current of a motor in the compressor is obtained;
determining whether a phase current of the motor fluctuates, comprising: determining a calculated value of the phase current of the motor, and recording the calculated value as the calculated phase current; determining whether the calculated phase current of the motor is greater than or equal to a set current threshold; if the calculated phase current of the motor is determined to be larger than or equal to the current threshold, determining that the phase current of the motor fluctuates; wherein determining a calculated value of the phase current of the motor, recorded as the calculated phase current, comprises: determining an effective value of the phase current of the motor, and recording the effective value as the effective phase current of the motor; filtering the effective phase current of the motor to obtain a filtering current value, and recording the filtering current value as the filtering phase current of the motor; filtering phase currents of the motor, corresponding to the phase currents of the motor, sampled at different sampling points in a set sampling period, form a filtering phase current sequence; determining a maximum filtering phase current and a minimum filtering phase current in the filtering current sequence; determining the difference value of the maximum filtering phase current and the minimum filtering phase current as the calculated value of the phase current of the motor, and recording the calculated value as the calculated phase current;
if the phase current of the motor is determined to fluctuate, determining that the current running state of the compressor is abnormal;
and under the condition that the current running state of the compressor is abnormal, triggering a preset abnormal protection mechanism to control the compressor to stop.
2. The method of claim 1, wherein determining whether phase current of the motor fluctuates further comprises:
after determining that the calculated phase current of the motor is greater than or equal to the current threshold value and before determining that the phase current of the motor fluctuates, determining whether the situation that the frequency that the calculated phase current of the motor is greater than or equal to the current threshold value is greater than or equal to the set frequency continuously occurs within the set calculation time; wherein, every time the calculated phase current of the motor is determined to be greater than or equal to the current threshold value once, 1 is added to the number of times that the calculated phase current of the motor is greater than or equal to the current threshold value;
if the condition that the frequency that the calculated phase current of the motor is larger than or equal to the current threshold value is larger than or equal to the set frequency is determined to continuously appear, determining that the phase current of the motor fluctuates;
and if the condition that the frequency that the calculated phase current of the motor is larger than or equal to the current threshold value is smaller than the set frequency is determined to continuously occur, re-determining the calculated value of the phase current of the motor.
3. The method for protecting a compressor according to any one of claims 1 to 2, wherein triggering a preset abnormal protection mechanism includes:
and stopping the output of the PWM signal of the motor in the compressor, and initiating a warning message for protecting the compressor when the current running state of the compressor is abnormal.
4. A protection device for a compressor, comprising:
an obtaining unit configured to obtain a phase current of a motor in the compressor in a case where the compressor is operated in a current operation state;
a control unit configured to determine whether phase current of the motor fluctuates, including: determining a calculated value of the phase current of the motor, and recording the calculated value as the calculated phase current; determining whether the calculated phase current of the motor is greater than or equal to a set current threshold; if the calculated phase current of the motor is determined to be larger than or equal to the current threshold, determining that the phase current of the motor fluctuates; wherein the control unit, determining a calculated value of the phase current of the motor, recorded as the calculated phase current, comprises: determining an effective value of the phase current of the motor, and recording the effective value as the effective phase current of the motor; filtering the effective phase current of the motor to obtain a filtering current value, and recording the filtering current value as the filtering phase current of the motor; filtering phase currents of the motor, corresponding to the phase currents of the motor, sampled at different sampling points in a set sampling period, form a filtering phase current sequence; determining a maximum filtering phase current and a minimum filtering phase current in the filtering current sequence; determining the difference value of the maximum filtering phase current and the minimum filtering phase current as the calculated value of the phase current of the motor, and recording the calculated value as the calculated phase current;
the control unit is further configured to determine that the current operation state of the compressor is abnormal if it is determined that the phase current of the motor fluctuates;
the control unit is further configured to trigger a preset abnormal protection mechanism to control the compressor to stop when the current operation state of the compressor is abnormal.
5. The compressor protection apparatus of claim 4, wherein the control unit determines whether a phase current of the motor fluctuates, further comprising:
after determining that the calculated phase current of the motor is greater than or equal to the current threshold value and before determining that the phase current of the motor fluctuates, determining whether the situation that the frequency that the calculated phase current of the motor is greater than or equal to the current threshold value is greater than or equal to the set frequency continuously occurs within the set calculation time; wherein, every time the calculated phase current of the motor is determined to be greater than or equal to the current threshold value once, adding 1 to the number of times that the calculated phase current of the motor is greater than or equal to the current threshold value;
if the condition that the frequency that the calculated phase current of the motor is larger than or equal to the current threshold value is larger than or equal to the set frequency is determined to continuously appear, determining that the phase current of the motor fluctuates;
and if the condition that the frequency that the calculated phase current of the motor is larger than or equal to the current threshold value is smaller than the set frequency is determined to continuously occur, re-determining the calculated value of the phase current of the motor.
6. The protection apparatus for a compressor according to any one of claims 4 to 5, wherein the control unit, which triggers a preset abnormal protection mechanism, comprises:
and stopping the output of the PWM signal of the motor in the compressor, and initiating a warning message for protecting the compressor when the current running state of the compressor is abnormal.
7. An air conditioning assembly, comprising: a protection device for a compressor according to any one of claims 4 to 6.
8. A storage medium, characterized in that the storage medium comprises a stored program, wherein the apparatus in which the storage medium is located is controlled to perform the protection method of a compressor according to any one of claims 1 to 3 when the program is run.
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| CN116155164B (en) * | 2023-04-24 | 2023-07-18 | 之江实验室 | Current control method, device, electronic device and storage medium |
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