CN111308164B - Voltage detection method and system, power supply circuit, air conditioning equipment and storage medium - Google Patents
Voltage detection method and system, power supply circuit, air conditioning equipment and storage medium Download PDFInfo
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- CN111308164B CN111308164B CN202010195744.9A CN202010195744A CN111308164B CN 111308164 B CN111308164 B CN 111308164B CN 202010195744 A CN202010195744 A CN 202010195744A CN 111308164 B CN111308164 B CN 111308164B
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The invention provides a voltage detection method and system, a power supply circuit, air conditioning equipment and a storage medium, wherein the voltage detection method comprises the following steps: collecting voltage data of a bus and determining corresponding cut-off frequency; filtering the voltage data according to the cut-off frequency to obtain voltage detection data; and determining a corresponding detection value according to the voltage detection data, and determining a voltage detection result corresponding to the bus according to the detection value and a corresponding detection threshold value. According to the technical scheme provided by the invention, the voltage data of the bus is determined by directly utilizing the bus acquisition data in the original system, a bus voltage detection device does not need to be additionally arranged in the original power supply system, and the cost is lower. The detection of the fluctuation of the bus voltage such as drop, power failure and the like is completed according to the detection value, the influence of the fluctuation of the bus voltage on electric equipment such as a magnetic suspension compressor and the like is effectively prevented, and the reliability of power supply detection and the operation reliability of the electric equipment are improved.
Description
Technical Field
The invention relates to the technical field of power supply detection, in particular to a voltage detection method, a voltage detection system, a power supply circuit, air conditioning equipment and a computer readable storage medium.
Background
In the related art, the input side voltage fluctuation can have great influence on the operation of electric equipment, for example, a magnetic suspension compressor, once the input side voltage drops to cause the power failure of a magnetic suspension controller, a bearing rotating at a high speed loses control and falls, and the bearing is damaged.
Therefore, an efficient and fast voltage detection method is needed.
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 invention proposes a voltage detection method.
A second aspect of the present invention provides a voltage detection system.
A third aspect of the invention provides a power supply circuit.
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 voltage detection method, including: collecting voltage data of a bus and determining corresponding cut-off frequency; filtering the voltage data according to the cut-off frequency to obtain voltage detection data; and determining a corresponding detection value according to the voltage detection data, and determining a voltage detection result corresponding to the bus according to the detection value and a corresponding detection threshold value.
According to the technical scheme, voltage data of the bus are filtered by the corresponding cut-off frequency to obtain voltage detection data, and the voltage detection data can reflect the change situation of the bus voltage, such as the fast change situation and the slow change situation, according to the difference of the cut-off frequency. And the corresponding detection value is determined according to the detection data, the detection value can reflect the speed of the change of the bus voltage, namely the fluctuation condition of the bus voltage, whether the bus voltage fluctuates or not can be accurately judged according to the comparison result of the detection value and the corresponding detection threshold value, the corresponding voltage detection result is output, and accurate and quick voltage detection is realized.
According to the technical scheme provided by the invention, the voltage data of the bus is determined by directly utilizing the bus acquisition data in the original system, a bus voltage detection device does not need to be additionally arranged in the original power supply system, and the cost is lower. Meanwhile, the voltage data of the bus is subjected to algorithm filtering by setting the corresponding cut-off frequency to obtain voltage detection data capable of reflecting the voltage change of the bus, so that a detection value capable of reflecting the voltage fluctuation of the bus is determined, and the detection of whether the voltage of the bus fluctuates, such as drop, power failure and the like, is finished according to the detection value, thereby effectively preventing the influence of the voltage fluctuation of the bus on electric equipment, such as a magnetic suspension compressor and the like, and improving the reliability of power supply detection and the operation reliability of the electric equipment.
In addition, the voltage detection method 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 filtering the bus voltage data to obtain the voltage detection data includes that the cut-off frequency includes a first frequency and a second frequency: performing first filtering on the voltage data according to a first frequency, and determining first voltage detection data according to a preset formula; performing second filtering on the voltage data according to a second frequency, and determining second voltage detection data according to a preset formula; wherein the first frequency is less than the second frequency.
In the technical scheme, when the voltage data of the bus is filtered, the voltage data of the bus is filtered twice by adopting the first frequency and the second frequency respectively. The first frequency is smaller than the second frequency, low-pass filtering signals with low cut-off frequency can be obtained by performing first filtering with the first frequency as the cut-off frequency, first voltage detection data are obtained through calculation according to a preset formula, and the data reflect the slow change condition of the bus voltage. And performing second filtering by taking the second frequency as a cut-off frequency to obtain a low-pass filtering signal with a high cut-off frequency, and calculating according to a preset formula to obtain second voltage detection data, wherein the data reflects the rapid change condition of the bus voltage.
The bus voltage detection value is determined according to the first filtering signal and the second filtering signal, so that the bus voltage change speed can be accurately reflected by the detection value, the accurate fluctuation condition of the bus voltage can be visually obtained, and the bus voltage detection is more accurate. Meanwhile, filtering is performed through an algorithm low-pass filter, on one hand, the response is rapid and accurate, false alarm can be reduced, the situation that the response is not timely can be avoided, on the other hand, a voltage detection device does not need to be added in the system, and therefore the cost is saved.
In any of the above technical solutions, the preset formula specifically is:
UDC_CutOff(k)＝a×UDC(k)+(1-a)×UDC_CutOff(k-1)；
where a is a natural number, a is 2 × pi × f × T, f is a cut-off frequency, T is a sampling period corresponding to voltage data, k is a detection period, UDC _ CutOff (k) is voltage detection data corresponding to a current detection period, UDC _ CutOff (k-1) is filtered voltage data corresponding to a previous detection period, and UDC (k) is voltage data corresponding to the current detection period.
In the technical scheme, the cut-off frequency f and the detection period k can be freely adjusted according to actual requirements, and further the method can adapt to the actual requirements of various power utilization environments.
In any of the above technical solutions, the step of determining the corresponding detection value according to the voltage detection data specifically includes: a difference value of the first voltage detection data and the second voltage detection data is calculated to determine a detection value.
In this embodiment, the difference between the first voltage detection data and the second voltage detection data is a detected value of the bus voltage. Specifically, the first voltage detection data is a low-pass filtered signal with a low cut-off frequency, and the second voltage detection data is a low-pass filtered signal with a high cut-off frequency, so that the difference value of the first voltage detection data and the second voltage detection data can reflect the falling amplitude of the bus voltage in two adjacent detection periods, namely directly reflects the speed of the change of the bus voltage, and the accurate detection of the bus voltage signal can be completed through a simple calculation process.
In any of the above technical solutions, the step of determining the voltage drop detection result corresponding to the bus according to the detection value and the corresponding detection threshold specifically includes: determining that the detection value is greater than or equal to the detection threshold value, and determining that the voltage drop occurs in the bus; and determining that the detection value is smaller than the detection threshold value, and determining that the bus does not have voltage drop.
In this technical solution, a difference between the first voltage detection data and the second voltage detection data may reflect a falling range of the bus voltage in two adjacent detection periods, so that if the difference between the first voltage detection data and the second voltage detection data is large, specifically, the detection value is greater than a preset detection threshold, it indicates that the bus voltage has a rapid drop or a power failure occurs, and at this time, a corresponding protection measure is executed. If the detection value is smaller than the preset detection threshold value, the situation that the fluctuation of the bus voltage is small and the voltage does not drop quickly is shown, and the electric equipment can run normally.
The detection threshold value can be specifically set according to the actual operation condition of the power grid, and if the voltage fluctuation of the power grid bus is large, the detection threshold value can be properly increased so as to ensure the normal operation of the power utilization equipment. If the fluctuation of the bus voltage is small or the electric equipment is sensitive to the voltage fluctuation, the detection threshold value can be properly reduced to ensure the use safety of the electric equipment. By freely adjusting the detection threshold value, the operation safety of the electric equipment can be guaranteed on the premise of guaranteeing the normal operation of the electric equipment.
In any of the above technical solutions, it is determined that a voltage drop occurs in the bus, and the voltage detection method further includes: and generating a corresponding protection signal and sending the protection signal to the protection controller so that the protection controller executes a corresponding voltage drop protection program.
In the technical scheme, when the bus voltage drops, the control system generates a corresponding protection signal and sends the protection signal to the protection controller, and the protection controller executes a preset voltage drop protection program to ensure that the electric equipment cannot be influenced by the voltage drop and ensure the stable operation and the safe operation of the electric equipment.
The control system and the protection controller are both provided with energy storage devices, and can keep working by electric energy stored in the energy storage devices under the condition of input voltage drop or power failure so as to ensure that a voltage drop protection program can be smoothly executed.
In any of the above solutions, the range of the first frequency is: greater than or equal to 0Hz and less than 300 Hz; the range of the second frequency is: greater than 300 Hz; the range of the detection period is: greater than or equal to 100 μ s and less than or equal to 500 μ s.
In the technical scheme, the first frequency, the second frequency and the detection period can be adjusted according to the actual electricity utilization environment and the hardware performance of the detection system, specifically, the first frequency can be set in a range of less than 300Hz, the second frequency can be set in a range of more than 300Hz, and the detection period can be set in a microsecond range, such as between 100 μ s and 500 μ s.
A second aspect of the present invention provides a voltage detection system, comprising: a memory configured to store a computer program; the processor is configured to execute a computer program to implement the voltage detection method provided in any of the above technical solutions, and therefore, the voltage detection system includes all the beneficial effects of the voltage detection method provided in any of the above technical solutions, which are not described herein again.
A third aspect of the present invention provides a power supply circuit, comprising: the input end of the rectifier is connected with the bus; the input end of the inverter is connected with the output end of the rectifier, and the input end of the inverter is configured to supply power to a load; the controller, the controller is connected with the control end of generating line and inverter, and the controller includes: the bus voltage detection unit is connected with the bus and is configured to acquire voltage data of the bus; according to the voltage detection system provided by any one of the technical schemes, the voltage detection system is connected with the bus voltage detection unit and the control end of the inverter.
In the technical scheme, the power supply circuit comprises a rectifier and an inverter, the controller is connected with the inverter, and the voltage data of the bus voltage is detected through a bus voltage detection unit. Meanwhile, the controller further includes a voltage detection system provided in any of the above technical solutions, so that the power supply circuit further includes all the beneficial effects of the voltage detection system provided 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, including a compressor and the power supply circuit provided in any one of the above technical solutions, where the power supply circuit is configured to supply power to the compressor, and therefore, the air conditioning apparatus includes all the beneficial effects of the power supply circuit provided in any one of the above technical solutions, which are not described herein again.
A fifth aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the voltage detection method provided in any of the above technical solutions, and therefore, the computer-readable storage medium includes all the beneficial methods of the voltage detection method provided in any of the above technical solutions, which are not described herein again.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 shows a flow diagram of a voltage detection method according to an embodiment of the invention;
FIG. 2 illustrates another flow diagram of a voltage detection method according to one embodiment of the invention;
FIG. 3 shows a block diagram of a voltage detection system according to an embodiment of the invention;
FIG. 4 shows a schematic diagram of a power supply circuit according to an embodiment of the invention;
FIG. 5 is a schematic diagram of a controller in a power supply circuit according to one embodiment of the invention;
FIG. 6 illustrates yet another flow diagram of a voltage detection method according to an embodiment of the invention;
FIG. 7 shows a logic diagram of low pass filtering in a voltage detection method according to an embodiment of the invention.
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.
The voltage detection method, the voltage detection system, the power supply circuit, the air conditioner, and the computer-readable storage medium according to some embodiments of the present invention are described below with reference to fig. 1 to 7.
Example one
As shown in fig. 1, in an embodiment of the first aspect of the present invention, there is provided a voltage detection method including:
step S102, collecting voltage data of a bus, and determining a corresponding cut-off frequency;
step S104, filtering the voltage data according to the cut-off frequency to obtain voltage detection data;
and S106, determining a corresponding detection value according to the voltage detection data, and determining a voltage detection result corresponding to the bus according to the detection value and a corresponding detection threshold value.
In step S104, the cut-off frequency includes a first frequency and a second frequency, and as shown in fig. 2, the step of filtering the bus voltage data to obtain the voltage detection data specifically includes:
step S202, performing first filtering on the voltage data according to a first frequency, and determining first voltage detection data according to a preset formula;
step S204, performing second filtering on the voltage data according to a second frequency, and determining second voltage detection data according to a preset formula;
wherein the first frequency is less than the second frequency.
When the voltage data of the bus is filtered, the voltage data of the bus is filtered twice by adopting the first frequency and the second frequency respectively. The first frequency is smaller than the second frequency, low-pass filtering signals with low cut-off frequency can be obtained by performing first filtering with the first frequency as the cut-off frequency, first voltage detection data are obtained through calculation according to a preset formula, and the data reflect the slow change condition of the bus voltage. And performing second filtering by taking the second frequency as a cut-off frequency to obtain a low-pass filtering signal with a high cut-off frequency, and calculating according to a preset formula to obtain second voltage detection data, wherein the data reflects the rapid change condition of the bus voltage.
The bus voltage detection value is determined according to the first filtering signal and the second filtering signal, so that the bus voltage detection value can accurately reflect the change speed of the bus voltage, the accurate fluctuation condition of the bus voltage can be visually obtained, and the bus voltage detection is more accurate. Meanwhile, filtering is performed through the algorithm low-pass filter, on one hand, response is rapid and accurate, false alarm can be reduced, the situation that response is not timely is avoided, on the other hand, a voltage detection device does not need to be added in the system, and therefore cost is saved.
In step S202 and step S204, the preset formula specifically includes:
UDC_CutOff(k)＝a×UDC(k)+(1-a)×UDC_CutOff(k-1)；
where a is a natural number, a is 2 × pi × f × T, f is a cut-off frequency, T is a sampling period corresponding to voltage data, k is a detection period, UDC _ CutOff (k) is voltage detection data corresponding to a current detection period, UDC _ CutOff (k-1) is filtered voltage data corresponding to a previous detection period, and UDC (k) is voltage data corresponding to the current detection period.
The range of the first frequency is: greater than or equal to 0Hz and less than 300 Hz; the range of the second frequency is: greater than 300 Hz; the range of the detection period is: greater than or equal to 100 μ s and less than or equal to 500 μ s.
The first frequency, the second frequency and the detection period can be adjusted according to the actual electricity environment and the hardware performance of the detection system, specifically, the first frequency can be set in a range of less than 300Hz, the second frequency can be set in a range of more than 300Hz, and the detection period can be set in a microsecond range, such as between 100 mus and 500 mus.
The first frequency is 10Hz and the second frequency is 500Hz, and the first voltage detection data is:
UDC_CutOff(k)_10Hz＝a 1 ×UDC(k)_10Hz+(1-a 1 )×UDC_CutOff(k-1)_10Hz；
a 1 ＝2×π×f×T；
when the sampling period is 0.0001s, a1 is 0.00628.
The second voltage data is:
UDC_CutOff(k)_500Hz＝a 2 ×UDC(k)_500Hz+(1-a 2 )×UDC_CutOff(k-1)_500Hz；
a 2 ＝2×π×f×T；
here, in the case where the sampling period is 0.0001s, a2 is 0.314.
After the first voltage data and the second voltage data are obtained, in step S106, the step of determining a corresponding detection value according to the voltage detection data specifically includes: a difference value between the first voltage detection data and the second voltage detection data is calculated to determine a detection value.
The step of determining a voltage drop detection result corresponding to the bus according to the detection value and the corresponding detection threshold specifically includes: determining that the detection value is greater than or equal to the detection threshold value, and determining that the voltage drop occurs in the bus; and determining that the detection value is smaller than the detection threshold value, and determining that the bus does not have voltage drop.
Determining that the bus has voltage drop, wherein the voltage detection method further comprises the following steps: and generating a corresponding protection signal, and sending the protection signal to a protection controller so that the protection controller executes a corresponding voltage drop protection program.
The difference between the first voltage detection data and the second voltage detection data is a detected value of the bus voltage. Specifically, the first voltage detection data is a low-pass filtered signal with a low cut-off frequency, and the second voltage detection data is a low-pass filtered signal with a high cut-off frequency, so that the difference value of the first voltage detection data and the second voltage detection data can reflect the falling amplitude of the bus voltage in two adjacent detection periods, namely directly reflects the speed of the change of the bus voltage, and the accurate detection of the bus voltage signal can be completed through a simple calculation process.
The difference value of the first voltage detection data and the second voltage detection data can reflect the descending amplitude of the bus voltage in two adjacent detection periods, so that if the difference value of the first voltage detection data and the second voltage detection data is larger, specifically, if the detection value is larger than a preset detection threshold value, it is indicated that the bus voltage has a rapid drop or a power failure occurs, and at this time, a corresponding protection measure is executed. If the detection value is smaller than the preset detection threshold value, the situation that the fluctuation of the bus voltage is small and the voltage does not drop quickly is shown, and the electric equipment can run normally.
The detection threshold value can be specifically set according to the actual operation condition of the power grid, and if the voltage fluctuation of the power grid bus is large, the detection threshold value can be properly increased so as to ensure the normal operation of the power utilization equipment. If the fluctuation of the bus voltage is small or the electric equipment is sensitive to the voltage fluctuation, the detection threshold value can be properly reduced to ensure the use safety of the electric equipment. By freely adjusting the detection threshold value, the operation safety of the electric equipment can be guaranteed on the premise of guaranteeing the normal operation of the electric equipment.
When the bus voltage drops, the control system generates corresponding protection signals and sends the protection signals to the protection controller, and the protection controller executes a preset voltage drop protection program to ensure that the electric equipment cannot be influenced by voltage drop and ensure the stable operation and safe operation of the electric equipment.
The control system and the protection controller are provided with energy storage devices, and under the condition that the input voltage is dropped or the power is cut off, the electric energy stored in the energy storage devices keeps working so as to ensure that a voltage drop protection program can be smoothly executed.
According to the embodiment of the invention, the voltage data of the bus is filtered by the corresponding cut-off frequency to obtain the voltage detection data, and the voltage detection data can reflect the change situation of the bus voltage, such as the fast change situation and the slow change situation, according to the difference of the cut-off frequency. And the corresponding detection value is determined according to the detection data, the detection value can reflect the speed of the change of the bus voltage, namely the fluctuation condition of the bus voltage, whether the bus voltage fluctuates or not can be accurately judged according to the comparison result of the detection value and the corresponding detection threshold value, the corresponding voltage detection result is output, and accurate and quick voltage detection is realized.
Specifically, the voltage data of the bus is determined by directly utilizing the bus acquisition data in the original system, a bus voltage detection device does not need to be additionally arranged in the original power supply system, and the cost is low. Meanwhile, the voltage data of the bus is subjected to algorithm filtering by setting the corresponding cut-off frequency to obtain voltage detection data capable of reflecting the voltage change of the bus, so that a detection value capable of reflecting the voltage fluctuation of the bus is determined, and the detection of whether the voltage of the bus fluctuates, such as drop, power failure and the like, is finished according to the detection value, thereby effectively preventing the influence of the voltage fluctuation of the bus on electric equipment, such as a magnetic suspension compressor and the like, and improving the reliability of power supply detection and the operation reliability of the electric equipment.
Example two
As shown in fig. 3, in one embodiment of the present invention, there is provided a voltage detection system 300, comprising: a memory 302 configured to store a computer program; the processor 304 is configured to execute a computer program to implement the voltage detection method provided in any of the above embodiments, and therefore, the voltage detection system 300 includes all the advantages of the voltage detection method provided in any of the above embodiments, which are not described herein again.
EXAMPLE III
As shown in fig. 4 and 5, in one embodiment of the present invention, a power supply circuit 400 is provided, comprising: a rectifier 402, an input end of the rectifier 402 is connected with the bus; an inverter 404, an input of the inverter 404 being connected to an output of the rectifier 402, the input of the inverter 404 being configured to supply power to a load; a controller 406, the controller 406 being connected to the bus and to a control terminal of the inverter 404, the controller 406 comprising: the bus voltage detection unit 4062 is connected with the bus, and is configured to acquire voltage data of the bus; as in the voltage detection system 300 provided in any of the above embodiments, the voltage detection system 300 is connected to the bus voltage detection unit and the control terminal of the inverter; the detection result output unit 4064 is configured to output the detection result.
In this embodiment, the power supply circuit 400 includes a rectifier 402 and an inverter 404, and the controller 406 is connected to the inverter 404 and detects voltage data of the bus voltage by a bus voltage detection unit 4062. Meanwhile, the controller 406 further includes the voltage detection system 300 provided in any of the above embodiments, so that the power supply circuit 400 further includes all the advantages of the voltage detection system 300 provided in any of the above embodiments, which are not described herein again.
Example four
In an embodiment of the present invention, the following description will be made in detail in a power supply scenario of a permanent magnet synchronous motor:
in practical application, if the input of the permanent magnet synchronous motor is detected to be powered off or voltage drop occurs, the magnetic suspension controller in the permanent magnet synchronous motor is powered off, so that the rotating bearing is told to lose control and directly drop, and the bearing is damaged or even damaged due to high-speed friction. Therefore, a device for detecting the sudden drop of the input side power supply is needed to inform the system to perform corresponding protection work.
In order to avoid bearing damage, a voltage detection device is often required to be installed on the input side, and the input power supply is judged to have sudden voltage drop or power failure by detecting the comparison between the input voltage and the rated voltage. The method needs to install a detection device at the input side to increase the cost, and meanwhile, the comparison between the input voltage and the rated voltage can only reflect the magnitude of the input voltage and cannot reflect the change speed of the input voltage, so that the problems of false alarm, overcurrent and the like are easily caused when the response is not in time.
In order to solve the problem, the embodiment of the invention provides a method for judging input power failure by detecting the voltage of a direct current bus. As shown in fig. 4 and 5, the permanent magnet synchronous motor obtains power supply from the power grid through the power supply circuit 400.
In the operation process of the magnetic suspension set, the flow for judging whether the direct current bus is powered off is shown in fig. 6:
step S602, sampling a direct current bus voltage UDC;
wherein, direct current bus voltage UDC is detected through a sampling circuit.
Step S604, through the UDC low-pass filtering LPF1, cutting off the frequency by 10Hz to obtain UDC _ CutOff _10 Hz;
the method comprises the steps of sampling a direct current bus voltage, filtering the sampled direct current bus voltage by adopting a high-CutOff frequency low-pass filter LPF1, wherein the specific CutOff frequency is 500Hz, and obtaining UDC _ CutOff _500Hz, and the value reflects the rapid change of the direct current bus voltage.
Step S606, through the UDC low-pass filtering LPF2, the frequency is cut off by 500Hz to obtain UDC _ CutOff _500 Hz;
the sampling direct current bus voltage is filtered by adopting a low-cut-off frequency low-pass filter LPF2, wherein the specific cut-off frequency is 10Hz, and the UDC _ CutOff _10Hz is obtained, and the value reflects the slow change of the direct current bus voltage.
Step S608, calculate UDC _ Drop ═ UDC _ CutOff _10Hz-UDC _ CutOff _500Hz,
and calculating UDC _ Drop (UDC _ CutOff _10Hz-UDC _ CutOff _500 Hz), wherein the UDC _ Drop reflects the speed of the change of the direct-current bus voltage.
Step S610, judging whether UDC _ Drop > Ulimit is met; if yes, go to step S612, otherwise go back to step S602;
when the UDC _ Drop is greater than the preset detection threshold Ulimit, it indicates that the Drop of the dc bus voltage at a later time is large, and it can be determined that the input voltage has a rapid Drop or power failure.
And step S612, outputting a protection signal to inform the control system of detecting that the input voltage has rapid drop or power failure.
Wherein:
UDC_CutOff_10Hz(k)＝c×UDC(k)+(1-c)×UDC_CutOff_10Hz(k-1)；
a first-order low-pass filter LPF1 with a cut-off frequency of 10Hz, where UDC _ CutOff _10Hz (k) is the current-time low-pass filtered value, UDC _ CutOff _10Hz (k-1) is the last-time low-pass filtered value, and UDC (k) is the current-time dc bus voltage.
c is 2 × pi × f × T, f is 10Hz, and T is the dc bus voltage sampling period, for example, if the sampling period is 0.0001 seconds, c is 0.00628.
UDC_CutOff_500Hz(k)＝d×UDC(k)+(1-d)×UDC_CutOff_500Hz(k-1)
And a 1-order low-pass filter LPF2 with a cut-off frequency of 500Hz, wherein UDC _ CutOff _500Hz (k) is a low-pass filtered value at the current moment, UDC _ CutOff _500Hz (k-1) is a low-pass filtered value at the last moment, and UDC (k) is a direct current bus voltage at the current moment.
d is 2 × pi × f × T, f is 500Hz, T is a dc bus voltage sampling period, for example, a sampling period of 0.0001 second, and b is 0.314.
The threshold Ulimit is determined according to the fluctuation condition of the local power grid, and if the local bus voltage fluctuates more severely, the threshold Ulimit can be increased appropriately, for example, Ulimit is UDC × 20%.
Both the low pass filter LPF1 and the LPF2 can be implemented by an algorithm, and specific logic is shown in fig. 7.
According to the embodiment provided by the invention, on one hand, a detection circuit is not required to be additionally arranged on the input side, so that the additional production cost is not increased; on the other hand, the judgment method is simple and quick, and can reflect the speed of the change of the input voltage, so that the judgment response is timely, and false alarm is not easy to generate; on the other hand, each parameter in the embodiment of the invention can be adjusted according to actual conditions, and further the fluctuation characteristics of power grids in different regions can be realized, so that the compatibility is good, and the popularization is facilitated.
EXAMPLE five
In an embodiment of the present invention, there is provided an air conditioning apparatus, including a compressor and a power supply circuit provided in any one of the above embodiments, where the power supply circuit is configured to supply power to the compressor, and therefore, the air conditioning apparatus includes all the beneficial effects of the power supply circuit provided in any one of the above embodiments, which are not described herein again.
Example six
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 voltage detection method provided in any of the above embodiments, so that the computer-readable storage medium includes all the beneficial methods of the voltage detection method provided in any of the above embodiments, and the description thereof is omitted here.
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.
Claims (7)
1. A voltage detection method, comprising:
collecting bus voltage data and determining corresponding cut-off frequency;
filtering the bus voltage data according to the cut-off frequency to obtain voltage detection data;
determining a corresponding detection value according to the voltage detection data, and determining a voltage detection result corresponding to the bus according to the detection value and a corresponding detection threshold value;
the cut-off frequency includes a first frequency and a second frequency, and the step of filtering the bus voltage data to obtain voltage detection data specifically includes:
performing first filtering on the voltage data according to the first frequency, and determining first voltage detection data according to a preset formula;
performing second filtering on the voltage data according to the second frequency, and determining second voltage detection data according to the preset formula;
the first voltage detection data reflects the slow change condition of the bus voltage;
the second voltage detection data reflects the rapid change condition of the bus voltage;
wherein the first frequency is less than the second frequency;
the step of determining a corresponding detection value according to the voltage detection data specifically includes:
calculating a difference value between the first voltage detection data and the second voltage detection data to determine the detection value;
the detection value reflects the fluctuation condition of the bus voltage;
the step of determining a voltage drop detection result corresponding to the bus according to the detection value and the corresponding detection threshold specifically includes:
determining that the detection value is greater than or equal to the detection threshold value, and determining that the bus has voltage drop;
determining that the detection value is smaller than the detection threshold value, and determining that the bus does not have voltage drop;
the detection threshold is specifically set according to the running condition of the actual power grid;
the preset formula specifically comprises:
UDC_CutOff（k）=a×UDC（k）+（1-a）×UDC_CutOff（k-1）；
wherein the content of the first and second substances,ais a natural number, anda=2×π×f×T，fis the frequency of the said cut-off frequency,Tis the sampling period corresponding to the voltage data,kin order to detect the period of time,UDC_CutOff（k）the voltage detection data corresponding to the current detection period,UDC_ CutOff（k-1）the filtered voltage data corresponding to the previous detection period,UDC（k）and the voltage data corresponds to the current detection period.
2. The voltage detection method according to claim 1, wherein it is determined that a voltage sag occurs in the bus bar, the voltage detection method further comprising:
and generating a corresponding protection signal, and sending the protection signal to a protection controller so as to enable the protection controller to execute a corresponding voltage drop protection program.
3. The voltage detection method according to claim 1 or 2,
the range of the first frequency is: greater than or equal to 0Hz and less than 300 Hz;
the range of the second frequency is: greater than 300 Hz;
the range of the detection period is as follows: greater than or equal to 100 mus and less than or equal to 500 mus.
4. A voltage detection system, comprising:
a memory configured to store a computer program;
a processor configured to execute the computer program to implement the voltage detection method of any one of claims 1 to 3.
5. A power supply circuit, comprising:
the input end of the rectifier is connected with the bus;
an inverter having an input connected to the output of the rectifier, the input of the inverter configured to supply power to a load;
a controller connected to the bus and the control end of the inverter, the controller comprising:
the bus voltage detection unit is connected with the bus and is configured to acquire voltage data of the bus;
the voltage detection system of claim 4, connected to the bus voltage detection unit and a control terminal of the inverter.
6. An air conditioning apparatus, characterized by comprising:
a compressor;
the power supply circuit of claim 5, configured to supply power to the compressor.
7. A computer-readable storage medium having stored thereon a computer program, characterized in that,
the computer program, when executed by a processor, implements a voltage detection method as claimed in any one of claims 1 to 3.
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| CN113899963A (en) * | 2021-08-30 | 2022-01-07 | 科华数据股份有限公司 | Alternating current system interference electricity detection method and device and terminal equipment |
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| CN104502677A (en) * | 2014-11-17 | 2015-04-08 | 华为技术有限公司 | Method and device used for detecting voltage change |
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