Three-phase current sampling method, system, electronic device and storage medium

Abstract

The present invention provides a three-phase current sampling method, system, electronic device and storage medium, including: constructing a filtering formula of a digital filter; combining the current sampling value of any phase current in the three-phase current, the phase shift angle of the digital filter and the filtering formula to obtain a current filtering value; obtaining the maximum amplitude of the phase current based on the phase shift angle, the current filtering value and the current phase angle of the phase current; obtaining the current actual current value of the phase current based on the current phase angle of the phase current and the maximum amplitude. The use of this technical solution solves the technical problem in the prior art that the three-phase current obtained by sampling has large fluctuations due to the influence of the power tube switch, thereby affecting the motor accuracy, and ensures the smooth operation of the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of current sampling, and in particular to a three-phase current sampling method, system, electronic device and storage medium. Background Art

[0002] Accurately sampling the three-phase current of the brushless motor is a key factor in ensuring the control accuracy and performance of the brushless motor.

[0003] In the prior art, a method of connecting a sampling resistor in series with the three-phase lower bridge is generally used to sample the three-phase current, and the on-off of the three-phase current is controlled by a power tube switch. Therefore, under the influence of the power tube switch, the sampled three-phase current fluctuates greatly, thereby affecting the control accuracy of the brushless motor. Summary of the invention

[0004] The purpose of the present invention is to provide a three-phase current sampling method, system, heating device and storage medium to solve the technical problem in the prior art that the three-phase current obtained by sampling fluctuates greatly due to the influence of the power tube switch, thereby affecting the motor accuracy.

[0005] In a first aspect, the present invention provides a three-phase current sampling method, comprising:

[0006] Construct filtering formulas for digital filters;

[0007] Combining the current sampling value of any one phase of the three-phase current, the phase shift angle of the digital filter and the filtering formula to obtain a current filtering value;

[0008] Obtaining the maximum amplitude of the phase current based on the phase shift angle, the current filter value and the current phase angle of the phase current;

[0009] The current actual current value of the phase current is obtained based on the current phase angle of the phase current and the maximum amplitude.

[0010] As an embodiment of the present invention, the filtering formula is:

[0011] Y(n)=Y(n-1)+T2πf c (X(n)-Y(n))

[0012] Among them, X(n) is the input value of the digital filter at the current moment; Y(n) is the output value of the digital filter at the current moment; Y(n-1) is the output value of the digital filter at the previous moment; T is the sampling period of the digital filter; f c is the cutoff frequency of the digital filter.

[0013] As an embodiment of the present invention, the method for constructing the filtering formula includes:

[0014] The voltage formula for constructing the digital filter is:

[0015]

[0016] Construct the cut-off frequency formula of the digital filter:

[0017]

[0018] Combining the cut-off frequency formula with the voltage formula, an equivalent formula is obtained:

[0019]

[0020] The equivalent formula is transformed into a discrete formula to obtain a discrete formula:

[0021]

[0022] The discrete formula is subjected to filtering transformation to obtain the filtering formula:

[0023]

[0024] Where: V in is the input voltage of the digital filter; V out is the output voltage of the digital filter; R is the capacitive reactance of the digital filter; C is the capacitance of the digital filter; is the rate of change of the output voltage of the digital filter.

[0025] As an embodiment of the present invention, the current sampling value of any one phase current in the three-phase current, the phase shift angle of the digital filter and the filtering formula are combined to obtain the current filter value, which includes:

[0026] Construct the phase shift angle formula of the digital filter;

[0027] Taking a value of the phase shift angle, and using the value of the phase shift angle to calculate the phase shift angle formula, to obtain a relationship between the sampling frequency and the cutoff frequency of the digital filter;

[0028] Based on the relationship between the sampling frequency and the sampling period, a relationship between the cut-off frequency and the sampling period is obtained;

[0029] Combining the relationship between the cut-off frequency and the sampling period with the filtering formula to obtain a lag filtering formula;

[0030] The current sampling value of any phase current among the three-phase current is used to calculate the lag filtering formula to obtain the current filtering value of the phase current.

[0031] As an embodiment of the present invention, the phase shift angle formula is:

[0032]

[0033] The phase shift angle is taken, and the phase shift angle is substituted into the phase shift angle formula to obtain the relationship between the sampling frequency and the cutoff frequency of the digital filter:

[0034] The phase shift angle is set to 45°, and the phase shift angle formula is calculated using 45° to obtain the relationship between the sampling frequency and the cutoff frequency of the digital filter: f = f c ;

[0035] The relationship between the cut-off frequency and the sampling period is specifically: c =1 / T;

[0036] The hysteresis filtering formula is:

[0037]

[0038] The current filter value calculated by the lag filter formula is recorded as I l .

[0039] As an embodiment of the present invention, obtaining the maximum amplitude of the phase current based on the phase shift angle, the current filter value and the current phase angle of the phase current includes:

[0040] Constructing a first trigonometric function using the phase angle, the current filter value, the current phase angle of the phase current, and the maximum amplitude of the phase current;

[0041] The first trigonometric function is calculated using the phase shift angle, the current filter value, and the phase angle of the phase current to obtain the maximum amplitude of the phase current.

[0042] As an embodiment of the present invention, obtaining the current actual current value of the phase current based on the current phase angle of the phase current and the maximum amplitude includes:

[0043] constructing a second trigonometric function using the current phase angle of the phase current, the actual current value and the maximum amplitude;

[0044] The second trigonometric function is calculated using the current phase angle of the phase current and the maximum amplitude to obtain an actual current value.

[0045] As an embodiment of the present invention, the first trigonometric function is:

[0046]

[0047] Among them, I lis the current filter value; I max is the maximum value.

[0048] As an embodiment of the present invention, the second trigonometric function is:

[0049] I=cos(θ)×I max

[0050] Among them, I is the actual current value, and θ is the current phase angle of the phase current.

[0051] As an embodiment of the present invention, the first trigonometric function is:

[0052]

[0053] I l is the current filter value; I max is the maximum value.

[0054] As an embodiment of the present invention, the second trigonometric function is:

[0055]

[0056] I is the actual current value, and θ is the current phase angle of the phase current.

[0057] In a second aspect, the present invention provides a three-phase current sampling system, comprising:

[0058] A building block for building a filtering formula for a digital filter;

[0059] A first acquisition module is used to combine the current sampling value of any phase current of the three-phase current, the phase shift angle of the digital filter and the filtering formula to obtain a current filtered value;

[0060] A second acquisition module, configured to obtain a maximum amplitude of the phase current based on the phase shift angle, the current filter value and a current phase angle of the phase current;

[0061] The third acquisition module is used to obtain the current actual current value of the phase current based on the current phase angle of the phase current and the maximum amplitude.

[0062] In a third aspect, the present invention provides an electronic device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method described in the first aspect is implemented.

[0063] In a fourth aspect, the present invention provides a computer-readable storage medium, comprising:

[0064] A computer program is stored thereon, characterized in that when the computer program is executed by a processor, the method described in the first aspect is implemented.

[0065] Implementing the embodiments of the present invention will have the following beneficial effects:

[0066] In the present invention, a filtering formula of a digital filter is first constructed, and then the current sampling value of any phase current of the three-phase current is input, and the phase shift angle of the digital filter is combined with the filtering formula to obtain a current filtering value, so as to eliminate the influence of the power tube switch on the current sampling value; at the same time, the phase of the current filtering value lags behind the phase of the current sampling value by a certain angle, and the angle is equal to the phase shift angle of the digital filter. Therefore, the maximum amplitude of the phase current is obtained by the phase shift angle, the current filtering value and the current phase angle of the phase current. Finally, the actual current value of the phase current is obtained by the current phase angle and the maximum amplitude of the phase current, thereby eliminating the phase lag problem caused by the digital filter and improving the accuracy of the actual current value. The use of this technical solution solves the technical problem in the prior art that the three-phase current obtained by sampling has a large fluctuation due to the influence of the power tube switch, thereby affecting the accuracy of the motor, and ensures the smooth operation of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0068] Figure 1 A circuit diagram of three-phase current sampling of a motor shown in an embodiment of the present invention;

[0069] Figure 2 A schematic diagram of an RC first-order low-pass filter circuit shown in an embodiment of the present invention;

[0070] Figure 3 It is a structural block diagram of the three-phase current sampling method shown in an embodiment of the present invention;

[0071] Figure 4 It is a structural block diagram of an electronic device shown in an embodiment of the present invention. DETAILED DESCRIPTION

[0072] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0073] See also Figure 1 As shown, the motor M is driven by three-phase (first phase, second phase and third phase) alternating current, the on-off of the first phase current is controlled by the first power tube switch Q1, the on-off of the second phase current is controlled by the second power tube switch Q2, and the on-off of the third phase current is controlled by the third power tube switch Q3; at the same time, the first sampling resistor R1 is connected in series to the lower bridge of the first phase, and the current sampling value of the first phase current can be collected through the first sampling resistor R1; the second sampling resistor R2 is connected in series to the lower bridge of the second phase, and the current sampling value of the second phase current can be collected through the second sampling resistor R2; the third sampling resistor R3 is connected in series to the lower bridge of the third phase, and the current sampling value of the third phase current can be collected through the third sampling resistor R3.

[0074] However, under the influence of the first power tube switch Q1, the second power tube switch Q2, and the third power tube switch Q3, the current sampling values ​​of the three phases obtained by sampling fluctuate greatly. Based on this, the present invention provides a three-phase current sampling method.

[0075] See also Figure 3 , the three-phase current sampling method includes:

[0076] S1, construct the filtering formula of the digital filter;

[0077] S2, combining the current sampling value of any phase current in the three-phase current, the phase shift angle of the digital filter and the filtering formula to obtain a current filter value;

[0078] S3, obtaining the maximum amplitude of the phase current based on the phase shift angle, the current filter value and the current phase angle of the phase current;

[0079] S4. Obtain a current actual current value of the phase current based on the current phase angle of the phase current and the maximum amplitude.

[0080] In the present invention, a filtering formula of a digital filter is first constructed, and then the current sampling value of any phase current of the three-phase current is input, and the phase shift angle of the digital filter is combined with the filtering formula to obtain a current filtering value, so as to eliminate the influence of the power tube switch on the current sampling value; at the same time, the phase of the current filtering value lags behind the phase of the current sampling value by a certain angle, and the angle is equal to the phase shift angle of the digital filter. Therefore, the maximum amplitude of the phase current is obtained by the phase shift angle, the current filtering value and the current phase angle of the phase current. Finally, the actual current value of the phase current is obtained by the current phase angle and the maximum amplitude of the phase current, thereby eliminating the phase lag problem caused by the digital filter and improving the accuracy of the actual current value. The use of this technical solution solves the technical problem in the prior art that the three-phase current obtained by sampling has a large fluctuation due to the influence of the power tube switch, thereby affecting the accuracy of the motor, and ensures the smooth operation of the motor.

[0081] See also Figure 2 , shows an RC first-order low-pass filter circuit, which is composed of a resistor R and a capacitor C. A digital filter is simulated based on the RC first-order low-pass filter circuit.

[0082] Specifically, the filtering formula of the digital filter is:

[0083] Y(n)=Y(n-1)+T2πf c (X(n)-Y(n))

[0084] Among them, X(n) is the input value of the digital filter at the current moment; Y(n) is the output value of the digital filter at the current moment; Y(n-1) is the output value of the digital filter at the previous moment; T is the sampling period of the digital filter; f c is the cutoff frequency of the digital filter.

[0085] After collecting the current sampling value of any phase current, the current filter value can be obtained by combining the filtering formula and the phase shift angle of the digital filter.

[0086] In one embodiment, the filtering formula is constructed as follows:

[0087] The voltage formula for constructing the digital filter is:

[0088]

[0089] Construct the cut-off frequency formula of the digital filter:

[0090]

[0091] Combining the cut-off frequency formula with the voltage formula, an equivalent formula is obtained:

[0092]

[0093] The equivalent formula is transformed into a discrete formula to obtain a discrete formula:

[0094]

[0095] The discrete formula is subjected to filtering transformation to obtain the filtering formula:

[0096] Y(n)=Y(n-1)+T2πf c (X(n)-Y(n))

[0097] Where: V in is the input voltage of the digital filter; V out is the output voltage of the digital filter; R is the capacitive reactance of the digital filter; C is the capacitance of the digital filter; is the rate of change of the output voltage of the digital filter.

[0098] In this embodiment, the voltage formula of the digital filter is first constructed, and then the cutoff frequency formula of the digital filter is constructed. Since both the voltage formula and the cutoff frequency formula contain RC, the voltage formula and the cutoff frequency formula can be combined to obtain an equivalent formula; then, assuming that the input value of the digital filter at the current moment is X(n), the output value at the current moment is Y(n), the output value at the previous moment is Y(n-1), and the sampling period is T, the equivalent formula can be written as a discrete formula, and finally the discrete formula is sorted to obtain the filtering formula.

[0099] In one embodiment, the current sampling value of any one phase current of the three-phase current, the phase shift angle of the digital filter and the filtering formula are combined to obtain the current filter value, which includes:

[0100] The phase shift angle formula for constructing a digital filter is:

[0101] Taking a value of the phase shift angle, and using the value of the phase shift angle to calculate the phase shift angle formula, to obtain a relationship between the sampling frequency and the cutoff frequency of the digital filter;

[0102] Based on the relationship between the sampling frequency and the sampling period, a relationship between the cut-off frequency and the sampling period is obtained;

[0103] Combining the relationship between the cut-off frequency and the sampling period with the filtering formula to obtain a lag filtering formula;

[0104] The current sampling value of any phase current among the three-phase current is used to calculate the lag filtering formula to obtain the current filtering value of the phase current.

[0105] In this embodiment, a phase shift angle formula of a digital filter is first constructed, and then a value of the phase shift angle is taken based on actual conditions. After that, the phase shift angle formula can be calculated using the value of the phase shift angle to obtain the relationship between the sampling frequency and the cutoff frequency of the digital filter. Since the relationship between the sampling frequency and the sampling period and the relationship between the cutoff frequency and the sampling frequency both contain the sampling frequency, the relationship between the cutoff frequency and the sampling period can be obtained by combining the above two relationship formulas. Then, the relationship between the cutoff frequency and the sampling period is combined with the filtering formula to obtain a lag filtering formula. Finally, the current sampling value of any phase current in the three-phase current is used to calculate the lag filtering formula to obtain the current filter value of the phase current.

[0106] In some specific embodiments, the phase shift angle formula is:

[0107]

[0108] From this we can see that the phase shift angle formula is an inverse tangent function.

[0109] In some specific embodiments, the phase shift angle is taken, and the phase shift angle is substituted into the phase shift angle formula to obtain the relationship between the sampling frequency and the cutoff frequency of the digital filter as follows:

[0110] The phase shift angle is set to 45°, and the phase shift angle formula is calculated using 45° to obtain the relationship between the sampling frequency and the cutoff frequency of the digital filter: f = f c ;

[0111] Based on the fact that the phase shift angle formula is an inverse tangent function, the phase shift angle is set to 45°, so that the inverse tangent function takes a value of 1, that is, Therefore, the relationship between the sampling frequency and the cut-off frequency is: f = f c .

[0112] And f = 1 / T, so f c =f = 1 / T, that is, the relationship between the cut-off frequency and the sampling period is specifically: f c =1 / T.

[0113] Then f c =1 / T is substituted into the filtering formula to obtain the lag filtering formula:

[0114]

[0115] Substituting the current sampling value of any phase current in the three-phase current as X(n) into the above hysteresis filter formula, Y(n) can be calculated. Y(n) is the current filter value, and the current filter value is recorded as I l .

[0116] In one embodiment, obtaining the maximum amplitude of the phase current based on the phase shift angle, the current filter value and the current phase angle of the phase current includes:

[0117] Constructing a first trigonometric function using the phase shift angle, the current filter value, the current phase angle of the phase current, and the maximum amplitude of the phase current;

[0118] The first trigonometric function is calculated using the phase shift angle, the current filter value, and the phase angle of the phase current to obtain the maximum amplitude of the phase current.

[0119] In this embodiment, any phase current of the three-phase current changes according to a trigonometric function. Therefore, a trigonometric function can be constructed using the phase shift angle, the current filter value, the current phase angle of the phase current, and the maximum amplitude of the phase current, and is named the first trigonometric function; the first trigonometric function is then calculated using the phase shift angle, the current filter value, and the current phase angle of the phase to obtain the maximum amplitude of the phase current.

[0120] In some specific embodiments, the first trigonometric function is:

[0121]

[0122] Among them, I l is the current filter value; I max is the maximum value.

[0123] In some other specific embodiments, the first trigonometric function is:

[0124]

[0125] I l is the current filter value; I max is the maximum value.

[0126] That is, the cosine function can be used to represent the change of any phase current in the three-phase current, and the sine function can also be used to represent the change of the three-phase current. The cosine function and the sine function used to represent the change of the three-phase current differ by 90 degrees.

[0127] In one embodiment, obtaining the current actual current value of the phase current based on the current phase angle of the phase current and the maximum amplitude includes:

[0128] constructing a second trigonometric function using the current phase angle of the phase current, the actual current value and the maximum amplitude;

[0129] The second trigonometric function is calculated using the current phase angle of the phase current and the maximum amplitude to obtain an actual current value.

[0130] From the above, it can be seen that any phase current of the three-phase current changes according to the trigonometric function. Therefore, the current phase angle of the phase current, the actual current value of the current phase of the phase current and the maximum amplitude of the phase current can construct a trigonometric function, which is named the second trigonometric function. Then, the current phase angle and maximum amplitude of the phase current are used to calculate the first trigonometric function to obtain the actual current value of the current phase of the phase current.

[0131] In some specific embodiments, when the first trigonometric function is constructed as

[0132]

[0133] When , the second trigonometric function is constructed as follows:

[0134] I=coS(θ)×I max

[0135] Among them, I is the actual current value, and θ is the current phase angle of the phase current.

[0136] In some other specific embodiments, when the first trigonometric function is constructed as:

[0137]

[0138] When , the second trigonometric function is constructed as follows:

[0139]

[0140] I is the actual current value, and θ is the current phase angle of the phase current.

[0141] In some specific embodiments, the motor is controlled by SVPWM (Space Vector Pulse Width Modulation), and the current phase angle θ of the first phase current is obtained by the angle φ of the synthetic vector in the three-phase coordinate system at the current moment. a =φ, the current phase angle of the second phase current θ b =φ+120°, the current phase angle of phase c is θ c =φ+240°.

[0142] By using the above method, we can find the maximum amplitude of the first phase current I amax , the maximum amplitude of the second phase current I bmax , the maximum amplitude of the third phase current I cmax Then the actual current value of the first phase current at the current phase can be calculated as or a =cos(θ)×I amax; The actual current value of the first phase current at the current phase can be obtained as or, I b =cos(θ)×I bmax ; The actual current value of the first phase current at the current phase is or, I c =cos(θ)×I cmax .

[0143] The present invention also provides a three-phase current sampling system, comprising:

[0144] A building block for building a filtering formula for a digital filter;

[0145] A first acquisition module is used to combine the current sampling value of any phase current of the three-phase current, the phase shift angle of the digital filter and the filtering formula to obtain a current filtered value;

[0146] A second acquisition module, configured to obtain a maximum amplitude of the phase current based on the phase shift angle, the current filter value and a current phase angle of the phase current;

[0147] The third acquisition module is used to obtain the current actual current value of the phase current based on the current phase angle of the phase current and the maximum amplitude.

[0148] In one embodiment, the filtering formula is:

[0149] Y(n)=Y(n-1)+T2πf c (X(n)-Y(n))

[0150] Among them, X(n) is the input value of the digital filter at the current moment; Y(n) is the output value of the digital filter at the current moment; Y(n-1) is the output value of the digital filter at the previous moment; T is the sampling period of the digital filter; f c is the cutoff frequency of the digital filter.

[0151] In one embodiment, the construction module includes: a first construction unit, a second construction unit, a first combining unit, a first transforming unit, and a first transforming unit;

[0152] The first building block is used to construct the voltage formula for the digital filter:

[0153]

[0154] The second building block is used to construct the cutoff frequency formula of the digital filter:

[0155]

[0156] The first combining unit is used to combine the cut-off frequency formula and the voltage formula to obtain an equivalent formula:

[0157]

[0158] The first transformation unit is used to perform discrete transformation on the equivalent formula to obtain a discrete formula:

[0159]

[0160] The second transformation unit is used to perform filtering transformation on the discrete formula to obtain a filtering formula:

[0161] Y(n)=Y(n-1)+T2πf c (X(n)-Y(n))

[0162] Where: V in is the input voltage of the digital filter; V out is the output voltage of the digital filter; R is the capacitive reactance of the digital filter; C is the capacitance of the digital filter; is the rate of change of the output voltage of the digital filter.

[0163] In one embodiment, the first acquisition module includes a third construction unit, a first calculation unit, a second calculation unit, and a second combination unit;

[0164] The third construction unit is used to construct a phase shift angle formula of the digital filter;

[0165] The first calculation unit is used to take a value of the phase shift angle, and use the value of the phase shift angle to calculate the phase shift angle formula to obtain a relationship between the sampling frequency and the cutoff frequency of the digital filter;

[0166] The second calculation unit is used to obtain the relationship between the cut-off frequency and the sampling period based on the relationship between the sampling frequency and the sampling period;

[0167] The second combining unit is used to combine the relationship between the cut-off frequency and the sampling period with the filtering formula to obtain a lag filtering formula;

[0168] The third calculation unit is used to calculate the lag filtering formula using the current sampling value of any phase current among the three-phase currents to obtain the current filter value of the phase current.

[0169] In some specific embodiments, the phase shift angle formula is:

[0170]

[0171] The phase shift angle is taken, and the phase shift angle is substituted into the phase shift angle formula to obtain the relationship between the sampling frequency and the cutoff frequency of the digital filter:

[0172] The phase shift angle is set to 45°, and the phase shift angle formula is calculated using 45° to obtain the relationship between the sampling frequency and the cutoff frequency of the digital filter: f = f c ;

[0173] The relationship between the cut-off frequency and the sampling period is specifically: c =1 / T;

[0174] The hysteresis filtering formula is:

[0175]

[0176] The current filter value calculated by the lag filter formula is recorded as I la .

[0177] In one embodiment, the second acquisition module includes: a fourth construction unit and a fourth calculation unit;

[0178] The fourth constructing unit is used to construct a first trigonometric function using the phase angle, the current filter value, the current phase angle of the phase current and the maximum amplitude of the phase current;

[0179] The fourth calculation unit is used to calculate the first trigonometric function using the phase shift angle, the current filter value and the phase angle of the phase current to obtain the maximum amplitude of the phase current.

[0180] In one embodiment, the third acquisition module includes: a fifth construction unit and a fifth calculation unit;

[0181] The fifth constructing unit is used to construct a second trigonometric function using the current phase angle of the phase current, the actual current value and the maximum amplitude;

[0182] The fifth calculation unit is used to calculate the second trigonometric function using the current phase angle of the phase current and the maximum amplitude to obtain the actual current value.

[0183] In some specific embodiments, the first trigonometric function is:

[0184]

[0185] Among them, I la is the current filter value; I amax is the maximum value.

[0186] The second trigonometric function is:

[0187] Ia =cos(θ)×I amax

[0188] Among them, I a is the actual current value, and θ is the current phase angle of the phase current.

[0189] In some other specific embodiments, the first trigonometric function is:

[0190]

[0191] I la is the current filter value; I amax is the maximum value.

[0192] The second trigonometric function is:

[0193]

[0194] I a is the actual current value, and θ is the current phase angle of the phase current.

[0195] See also Figure 4 The electronic device includes: a memory 601, a processor 602, and a computer program stored in the memory 601 and executable on the processor 602. When the processor 602 executes the computer program, the three-phase current sampling method and system described in the above-mentioned embodiments are implemented.

[0196] Furthermore, the electronic device also includes: at least one input device 603 and at least one output device 604 .

[0197] The memory 601 , processor 602 , input device 603 and output device 604 are connected via a bus 605 .

[0198] The input device 603 may be a camera, a touch panel, a physical button or a mouse, etc. The output device 604 may be a display screen.

[0199] The memory 601 may be a high-speed random access memory (RAM) memory or a non-volatile memory, such as a disk memory. The memory 601 is used to store a set of executable program codes, and the processor 602 is coupled to the memory 601 .

[0200] Furthermore, the embodiment of the present application also provides a computer-readable storage medium, which may be disposed in the heating device in each of the above embodiments, and the computer-readable storage medium may be the aforementioned memory 601. The computer-readable storage medium stores a computer program, which, when executed by the processor 602, implements the three-phase current sampling method described in the above embodiments.

[0201] Furthermore, the computer storable medium may also be a U disk, a mobile hard disk, a read-only memory 601 (ROM), a RAM, a magnetic disk or an optical disk, and other media that can store program codes.

[0202] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0203] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0204] In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of software functional modules.

[0205] If the integrated module is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product.

[0206] It should be noted that, for the convenience of description, the aforementioned method embodiments are all described as a series of action combinations, but those skilled in the art should be aware that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0207] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0208] The above is a description of an automatic correction method and system for a galvanometer mark of a laser device provided by the present invention. For technicians in this field, according to the ideas of the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A three-phase current sampling method, characterized in that: include: Construct filtering formulas for digital filters; Combining the current sampling value of any one phase of the three-phase current, the phase shift angle of the digital filter and the filtering formula to obtain a current filtering value; Obtaining the maximum amplitude of the phase current based on the phase shift angle, the current filter value and the current phase angle of the phase current; Obtaining a current actual current value of the phase current based on the current phase angle of the phase current and the maximum amplitude; The step of combining the current sampling value of any one phase of the three-phase current, the phase shift angle of the digital filter and the filtering formula to obtain the current filter value includes: Construct the phase shift angle formula of the digital filter; Taking a value of the phase shift angle, and using the value of the phase shift angle to calculate the phase shift angle formula, to obtain a relationship between the sampling frequency and the cutoff frequency of the digital filter; Based on the relationship between the sampling frequency and the sampling period, a relationship between the cut-off frequency and the sampling period is obtained; Combining the relationship between the cut-off frequency and the sampling period with the filtering formula to obtain a lag filtering formula; Using the current sampling value of any phase current among the three-phase current to calculate the lag filtering formula, to obtain the current filtering value of the phase current; The obtaining of the maximum amplitude of the phase current based on the phase shift angle, the current filter value and the current phase angle of the phase current comprises: Constructing a first trigonometric function using the phase angle, the current filter value, the current phase angle of the phase current, and the maximum amplitude of the phase current; Calculate the first trigonometric function using the phase shift angle, the current filter value and the current phase angle of the phase to obtain the maximum amplitude of the phase current; The obtaining of the current actual current value of the phase current based on the current phase angle of the phase current and the maximum amplitude comprises: constructing a second trigonometric function using the current phase angle of the phase current, the actual current value and the maximum amplitude; The second trigonometric function is calculated using the current phase angle of the phase current and the maximum amplitude to obtain an actual current value.

2. The three-phase current sampling method according to claim 1, characterized in that: The filtering formula is: Y(n)=Y(n-1)+T2πf c (X(n)-Y(n)) Among them, X(n) is the input value of the digital filter at the current moment; Y(n) is the output value of the digital filter at the current moment; Y(n-1) is the output value of the digital filter at the previous moment; T is the sampling period of the digital filter; f c is the cutoff frequency of the digital filter.

3. The three-phase current sampling method according to claim 2, characterized in that: The method for constructing the filtering formula includes: The voltage formula for constructing the digital filter is: Construct the cut-off frequency formula of the digital filter: Combining the cut-off frequency formula with the voltage formula, an equivalent formula is obtained: The equivalent formula is transformed into a discrete formula to obtain a discrete formula: The discrete formula is subjected to filtering transformation to obtain the filtering formula: Y(n)=Y(n-1)+T2πf c (X(n)-Y(n)) Where: V in is the input voltage of the digital filter; V out is the output voltage of the digital filter; R is the capacitive reactance of the digital filter; C is the capacitance of the digital filter; is the rate of change of the output voltage of the digital filter.

4. The three-phase current sampling method according to claim 1, characterized in that: The phase shift angle formula is: The phase shift angle is taken, and the phase shift angle is substituted into the phase shift angle formula to obtain the relationship between the sampling frequency and the cutoff frequency of the digital filter: The phase shift angle is set to 45°, and the phase shift angle formula is calculated using 45° to obtain the relationship between the sampling frequency and the cutoff frequency of the digital filter: f = f c ; The relationship between the cut-off frequency and the sampling period is specifically: c =1 / T; The hysteresis filtering formula is: The current filter value calculated by the lag filter formula is recorded as I l .

5. The three-phase current sampling method according to claim 1, characterized in that: The first trigonometric function is: Among them, I l is the current filter value; θ is the current phase angle of the phase current, I max is the maximum value.

6. The three-phase current sampling method according to claim 5, characterized in that: The second trigonometric function is: I=cos(θ)×I max Among them, I is the actual current value, and θ is the current phase angle of the phase current.

7. The three-phase current sampling method according to claim 1, characterized in that: The first trigonometric function is: I l is the current filter value; θ is the current phase angle of the phase current, I max is the maximum value.

8. The three-phase current sampling method according to claim 7, characterized in that: The second trigonometric function is: I is the actual current value, and θ is the current phase angle of the phase current.

9. A three-phase current sampling system, applied to the three-phase current sampling method according to any one of claims 1 to 8, characterized in that: include: A building block for building a filtering formula for a digital filter; A first acquisition module is used to combine the current sampling value of any phase current of the three-phase current, the phase shift angle of the digital filter and the filtering formula to obtain a current filtered value; A second acquisition module, configured to obtain a maximum amplitude of the phase current based on the phase shift angle, the current filter value and a current phase angle of the phase current; The third acquisition module is used to obtain the current actual current value of the phase current based on the current phase angle of the phase current and the maximum amplitude.

10. An electronic device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method according to any one of claims 1 to 8 is implemented.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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