CN112798957A - Electric parameter calculation method and system of brushless generator set and storage medium - Google Patents
Electric parameter calculation method and system of brushless generator set and storage medium Download PDFInfo
- Publication number
- CN112798957A CN112798957A CN202110115943.9A CN202110115943A CN112798957A CN 112798957 A CN112798957 A CN 112798957A CN 202110115943 A CN202110115943 A CN 202110115943A CN 112798957 A CN112798957 A CN 112798957A
- Authority
- CN
- China
- Prior art keywords
- permanent magnet
- magnet machine
- frequency
- voltage
- sampling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/2503—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques for measuring voltage only, e.g. digital volt meters (DVM's)
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
- G01R23/02—Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
Abstract
The invention relates to a method, a system and a storage medium for calculating electrical parameters of a brushless generator set, wherein the method comprises the following steps of establishing a corresponding relation table of the frequency of a permanent magnet machine, the sampling point number of each cycle and the harmonic frequency according to the coaxial rotation characteristic of the permanent magnet machine and a generator; measuring the frequency of the permanent magnet machine and the frequency of the generator; based on the corresponding relation table, adjusting the sampling period for AC sampling of the voltage of the permanent magnet machine according to the ratio of the frequency of the permanent magnet machine to the frequency of the generator; AC sampling is carried out on the voltage of the permanent magnet machine according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle sampling point; and calculating the voltage of the permanent magnet machine according to the sampling point number and the harmonic frequency under the corresponding frequency of the permanent magnet machine in the corresponding relation table based on a harmonic calculation formula of Fourier transform. The invention is characterized in that the sampling point number is selected in a self-adaptive way without paying attention to the rated frequency of the permanent magnet machine, the voltage of the permanent magnet machine is accurately and quickly calculated according to the frequency of the permanent magnet machine, the applicability is strong, and the reliability is high.
Description
Technical Field
The invention relates to the field of motor excitation, in particular to a method and a system for calculating an electrical parameter of a brushless generator set and a storage medium.
Background
The generator excitation system is an independent system, is one of important systems for controlling the generator, and has the characteristics of real-time adjustment and quick response. The three-machine brushless generator set is simple to maintain and high in safety, an excitation transformer is replaced by a permanent magnet machine, and the cost is low, so that the three-machine brushless generator set is more and more widely used, but the faults of the permanent magnet machine happen occasionally, all existing excitation products do not have the function of monitoring the voltage of the permanent magnet machine, and in order to improve intelligent monitoring and quickly judge the faults, an excitation adjusting system is very necessary to monitor the voltage state of the permanent magnet machine, and the excitation system can judge the faults only by correctly measuring the voltage of the permanent magnet machine. The frequency of the generator in China is 50Hz, but the frequencies of the permanent magnet machines are all from 50Hz to 500Hz and are not necessarily integral multiples of 50Hz, most of the permanent magnet machines have higher frequencies, and some permanent magnet machines even do not mark rated frequencies. The permanent magnet machine is used for excitation rectification, and the voltage waveform distortion of the permanent magnet machine is serious, so that great difficulty is caused to the measurement of the voltage of the permanent magnet machine by an excitation system.
Disclosure of Invention
The invention aims to provide a method, a system and a storage medium for calculating the electrical parameters of a brushless generator set, which can accurately calculate the voltage of a permanent magnet motor and have strong applicability and high reliability.
The technical scheme for solving the technical problems is as follows: a method for calculating electric parameters of a brushless generator set, the brushless generator set comprises a generator and a permanent magnet machine, the electric parameters comprise permanent magnet machine voltage, the method for calculating the electric parameters comprises the following steps,
according to the coaxial rotation characteristic of the permanent magnet machine and the generator, a corresponding relation table of the frequency of the permanent magnet machine, the sampling point number of each cycle and the harmonic frequency is established in advance;
measuring the frequency of the permanent magnet machine, and measuring the frequency of the generator;
based on the corresponding relation table, adjusting the sampling period of AC sampling of the voltage of the permanent magnet machine according to the ratio of the frequency of the permanent magnet machine to the frequency of the generator, so that the number of sampling points of the permanent magnet machine under AC sampling of each cycle is the same as the number of sampling points under the frequency of the corresponding permanent magnet machine in the corresponding relation table;
carrying out alternating current sampling on the voltage of the permanent magnet machine according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle sampling point;
and calculating the voltage of the permanent magnet machine according to the voltage sampling value of the permanent magnet machine at each sampling point of the cycle and the sampling point number and the harmonic frequency of the permanent magnet machine corresponding to the frequency in the corresponding relation table based on a harmonic calculation formula of Fourier transform.
Based on the electric parameter calculation method of the brushless generator set, the invention also provides an electric parameter calculation system of the brushless generator set.
An electrical parameter calculation system of a brushless generator set, the brushless generator set comprising a generator and a permanent magnet machine, the electrical parameter calculation system being applied to the electrical parameter calculation method of the brushless generator set as described above, the electrical parameter comprising a permanent magnet machine voltage, the electrical parameter calculation system comprising the following modules,
the corresponding relation table establishing module is used for establishing a corresponding relation table of the frequency of the permanent magnet machine, the sampling point number of each cycle and the harmonic frequency in advance according to the coaxial rotation characteristic of the permanent magnet machine and the generator;
the frequency measurement module is used for measuring the frequency of the permanent magnet machine and the frequency of the generator;
the sampling point adjusting module is used for adjusting the sampling period of alternating current sampling of the voltage of the permanent magnet machine according to the ratio of the frequency of the permanent magnet machine to the frequency of the generator based on the corresponding relation table, so that the sampling points of the permanent magnet machine under the alternating current sampling of each cycle are the same as the sampling points under the corresponding frequency of the permanent magnet machine in the corresponding relation table;
the permanent magnet machine voltage sampling module is used for carrying out alternating current sampling on the permanent magnet machine voltage according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle sampling point;
and the permanent magnet machine voltage calculation module is used for calculating the permanent magnet machine voltage according to the voltage sampling value of the permanent magnet machine at each sampling point of the cycle and the sampling point number and the harmonic frequency of the permanent magnet machine at the corresponding frequency in the corresponding relation table based on a harmonic calculation formula of Fourier transform.
Based on the electric parameter calculation method of the brushless generator set, the invention also provides a computer storage medium.
A computer storage medium comprising a memory and a computer program stored in the memory, the computer program, when executed, implementing a method of calculating an electrical parameter of a brushless generator set as described above.
The invention has the beneficial effects that: the invention relates to a method, a system and a storage medium for calculating electric parameters of a brushless generator set, wherein a permanent magnet machine and a generator rotate coaxially, the frequency of the generator and the frequency of the permanent magnet machine always keep the same ratio, under the condition of not paying attention to the rated frequency of the permanent magnet machine, the number of sampling points is selected in a self-adaptive manner according to the ratio of the frequency of the permanent magnet machine to the frequency of the generator, the voltage of the permanent magnet machine is accurately and quickly calculated according to the frequency of the permanent magnet machine, and the method, the system and the storage; therefore, the invention can monitor the voltage of the permanent magnet machine on line with high precision, detect whether the output voltage of the permanent magnet machine is normal or not in real time, judge the fault and alarm.
Drawings
FIG. 1 is a flow chart of a method for calculating an electrical parameter of a brushless generator set according to the present invention;
FIG. 2 is a schematic circuit diagram of a frequency measurement circuit of a permanent magnet machine;
FIG. 3 is a schematic circuit diagram of a voltage sampling circuit of a permanent magnet machine;
FIG. 4 is a schematic diagram of a circuit configuration of a generator frequency measurement circuit;
FIG. 5 is a schematic diagram of a circuit configuration of a generator voltage sampling circuit;
fig. 6 is a block diagram of an electrical parameter calculation system of a brushless generator set according to the present invention.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.
As shown in fig. 1, an electrical parameter calculation method of a brushless generator set, the brushless generator set including a generator and permanent magnets, the electrical parameter including a permanent magnet voltage, the electrical parameter calculation method including the steps of,
the electrical parameter comprises a permanent magnet motor voltage, the electrical parameter calculation method comprises the following steps,
according to the coaxial rotation characteristic of the permanent magnet machine and the generator, a corresponding relation table of the frequency of the permanent magnet machine, the sampling point number of each cycle and the harmonic frequency is established in advance;
measuring the frequency of the permanent magnet machine, and measuring the frequency of the generator;
based on the corresponding relation table, adjusting the sampling period of AC sampling of the voltage of the permanent magnet machine according to the ratio of the frequency of the permanent magnet machine to the frequency of the generator, so that the number of sampling points of the permanent magnet machine under AC sampling of each cycle is the same as the number of sampling points under the frequency of the corresponding permanent magnet machine in the corresponding relation table;
carrying out alternating current sampling on the voltage of the permanent magnet machine according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle sampling point;
and calculating the voltage of the permanent magnet machine according to the voltage sampling value of the permanent magnet machine at each sampling point of the cycle and the sampling point number and the harmonic frequency of the permanent magnet machine corresponding to the frequency in the corresponding relation table based on a harmonic calculation formula of Fourier transform.
In the electrical parameter calculation method of the present invention: the frequencies of the permanent magnet machines used by the three-machine brushless generator researched and developed by the market are mainly the frequencies shown in table 1, and the established correspondence table is specifically shown in table 1.
Table 1: corresponding relation table
In the electrical parameter calculation method of the present invention: the specific steps for measuring the frequency of the permanent magnet machine are,
the output of the permanent magnet machine sequentially passes through a first voltage transformer and a first second-order low-pass filter to obtain an alternating voltage signal of the permanent magnet machine;
converting an alternating-current voltage signal of the permanent magnet machine into a first symmetrical square wave signal with the amplitude of +/-12V by using a first zero-crossing hysteresis comparison circuit;
converting the first square wave signal into a second symmetrical square wave signal which can be accepted by a CPU (Central processing Unit) and is 0-3.3V by using a first pulse amplitude limiting circuit;
capturing a first interval count value of two continuous pulse rising edges of the second symmetrical square wave signal by using a CPU (Central processing Unit), and calculating the frequency of the permanent magnet machine according to the system clock frequency of the CPU and the first interval count value; the calculation formula of the frequency of the permanent magnet machine is as follows,
wherein f istIs the permanent magnet machine frequency, F is the system clock frequency of the CPU, t1Is the first interval count value. In this embodiment, the system clock frequency of the CPU is 120 × 106MHz。
In this embodiment, a first zero-crossing hysteresis comparison circuit (a first zero-crossing hysteresis comparison circuit is composed of the resistor R96, the resistor R110, the resistor R109, the resistor R118, and the comparator U9D) and a first pulse amplitude limiting circuit (a first pulse amplitude limiting circuit is composed of the diode D8, the diode D50, the resistor R299, the resistor R121, and the inverter U59E) constitute a permanent magnet machine frequency measurement circuit, the inverter U59E is connected to a capture pin of the CPU, and a circuit structure of the permanent magnet machine frequency measurement circuit is as shown in fig. 2 (the permanent magnet machine frequency measurement circuit only needs to detect the frequency of any phase of the permanent magnet machine).
Because the voltage sampling value of the permanent magnet machine at each cycle sampling point is attenuated through the second-order filtering amplitude value, the voltage of the permanent magnet machine needs to be compensated, and the real voltage of the permanent magnet machine is obtained.
Further, the electrical parameter calculation method further includes the steps of,
calculating the amplification factor of the permanent magnet voltage under alternating current sampling according to the permanent magnet frequency and the element parameters in the first second-order low-pass filter, and compensating the permanent magnet voltage according to the amplification factor to obtain the actual value of the permanent magnet voltage; the actual value of the permanent magnet motor voltage is calculated according to the formula,
wherein, URMSAnd U is the voltage of the permanent magnet machine, and A is the amplification factor.
Further, the alternating current sampling is carried out on the voltage of the permanent magnet machine according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle sampling point, and the method specifically comprises the following steps,
and inputting the alternating voltage signal of the permanent magnet machine into an AD sampling chip, and carrying out alternating current sampling on the voltage of the permanent magnet machine by the AD sampling chip according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle of sampling point.
In this embodiment, the first voltage transformer and the first second-order low-pass filter form a permanent magnet machine voltage sampling circuit, and a circuit structure of the permanent magnet machine voltage sampling circuit is shown in fig. 3. The number of the first voltage transformers is three, namely a first voltage transformer PT7, a second first voltage transformer PT8 and a third first voltage transformer PT9 which correspond to the three phases of the permanent magnet motor; the voltage of the permanent magnet machine is generally between 80V and 350V, the three-phase voltage of the permanent magnet machine is connected to the primary sides of three 400V/7.07V first voltage transformers in a delta connection mode, and the secondary sides of the three first voltage transformers are respectively connected with a capacitor C7, a capacitor C8 and a capacitor C9 of 1nF in parallel and then are respectively connected to the input ends of the three groups of first second-order low-pass filters to inhibit high-frequency signals. The three first two-step low-pass filters are respectively a first two-step low-pass filter composed of a resistor R37, a resistor R43, a resistor R28, a capacitor C31, a capacitor C32 and a comparator U2B, a second first two-step low-pass filter composed of a resistor R56, a resistor R57, a resistor R58, a capacitor C33, a capacitor C34 and a comparator U2C, and a third first two-step low-pass filter composed of a resistor R59, a resistor R60, a resistor R61, a capacitor C35, a capacitor C36 and a comparator U2D, and the electrical parameters of the three first two-step low-pass filters are completely the same, wherein R37 ═ R43 ═ 36k Ω, R28 ═ 30k Ω, C31 ═ 22nF, and C32 ═ 4.7 nF. The outputs of the comparator U2B, the comparator U2C and the comparator U2D are connected to an AD sampling chip, and the outputs of the comparator U2B, the comparator U2C and the comparator U2D are also connected to the input ends of the three groups of first zero-crossing hysteresis comparison circuits in a one-to-one correspondence mode.
In the permanent magnet machine voltage sampling circuit shown in figure 3,
the first cutoff frequency is:
the magnification is:
in the electrical parameter calculation method of the present invention: the specific steps for measuring the frequency of the generator are,
outputting the PT secondary voltage special for generator excitation sequentially through a second voltage transformer and a second-order low-pass filter to obtain a first alternating voltage signal of the generator;
converting the first alternating voltage signal of the generator into a third symmetrical square wave signal with the amplitude of +/-12V by using a second zero-crossing hysteresis comparison circuit;
converting the third square wave signal into a fourth symmetrical square wave signal of 0-3.3V which can be accepted by a CPU by using a second pulse amplitude limiting circuit;
capturing a second interval count value of two continuous pulse rising edges of the fourth symmetrical square wave signal by using a CPU (Central processing Unit), and calculating the frequency of the generator according to the system clock frequency of the CPU and the second interval count value; the formula for calculating the frequency of the generator is,
wherein f isgIs the generator frequency, F is the system clock frequency of the CPU, t2Is the second interval count value. In this embodiment, the system clock frequency of the CPU is 120 × 106MHz。
In this embodiment, the second-order low-pass filter (the second-order low-pass filter is composed of a resistor R36, a resistor R42, a resistor R27, a capacitor C24, a capacitor C27 and an operational amplifier U2A), the second zero-crossing hysteresis comparison circuit (the second zero-crossing hysteresis comparison circuit is composed of a resistor R95, a resistor R98, a resistor R108, a resistor R117 and a comparator U9C), and the second pulse amplitude limiting circuit (the second pulse amplitude limiting circuit is composed of a diode D7, a diode D49, a resistor R298, a resistor R122 and an inverter U59D) constitute a generator frequency measurement circuit, the circuit structure of the generator frequency measurement circuit is as shown in fig. 4 (the generator frequency measurement circuit detects the frequency of any phase of the generator, it should be noted that the phase of the permanent magnet frequency measurement circuit detects the phase of the permanent magnet frequency and the phase of the generator frequency measurement circuit detects the phase of the generator frequency, that is the generator frequency measurement circuit detects the frequency of the phase a, the permanent magnet machine frequency measurement circuit also needs to detect the frequency of the permanent magnet machine a phase).
In the electrical parameter calculation method of the present invention: the electrical parameters also comprise rated frequency of the permanent magnet machine; the electrical parameter calculation method further comprises the steps of,
calculating the rated frequency of the permanent magnet machine according to the rated frequency of the generator, the frequency of the generator and the frequency of the permanent magnet machine;
the calculation formula of the rated frequency of the permanent magnet machine is as follows,
wherein f iseFor the rated frequency, f, of the permanent magnet machinetIs the frequency of said permanent magnet machine, fgFor the generator frequency, fHThe rated frequency of the generator. In this particular embodiment, the generator is rated for a frequency of 50 Hz.
Further, the electrical parameter further comprises a generator voltage; the electrical parameter calculation method further comprises the steps of,
outputting the PT secondary voltage special for generator excitation sequentially through a second voltage transformer and a first-order low-pass filter to obtain a second alternating voltage signal of the generator;
inputting a second alternating voltage signal of the generator into an AD sampling chip, wherein the AD sampling chip performs alternating current sampling on the voltage of the generator according to the sampling period to obtain a voltage sampling value of the generator at each cycle of wave sampling point;
calculating the voltage of the generator according to a voltage sampling value of the generator at each cycle sampling point;
and the sampling interval of the voltage of the permanent magnet motor is the same as that of the voltage of the generator.
In this embodiment, the second voltage transformer and the first-order low-pass filter form a generator voltage sampling circuit, and the circuit structure of the generator voltage sampling circuit is as shown in fig. 5. The number of the second voltage transformers is three, namely a first second voltage transformer PT1, a second voltage transformer PT2 and a third voltage transformer PT3 which correspond to the three phases of the generator; the voltage of the generator is taken from the secondary voltage output of the special PT for generator excitation, the rated output is 100V, the three secondary sides of the three second voltage transformers are respectively connected to the primary sides of three second voltage transformers of 200V/7.07V in a delta connection mode, secondary sides of the three second voltage transformers are respectively connected with a capacitor C1, a capacitor C2 and a capacitor C3 in parallel for high-frequency suppression, three-phase voltages are respectively subjected to first-order RC filtering through three groups of first-order low-pass filters (a first group of first-order low-pass filters is formed by a resistor R1 and a capacitor C11, a second group of first-order low-pass filters is formed by a resistor R2 and a capacitor C12, a third group of first-order low-pass filters is formed by a resistor R3 and a capacitor C13), R1 is 100k omega, C11 is 10nF, and NPO material capacitors are selected as C.
In the generator voltage sampling circuit shown in figure 5,
the second cut-off frequency is such that,
in the electrical parameter calculation method of the present invention: the harmonic calculation formula (discrete expression of fundamental wave of fourier series) based on fourier transform specifically,
wherein, anIs the real part of the nth harmonic, bnThe voltage sampling value of the permanent magnet machine at the kth sampling point of each cycle is N, N is the number of sampling points of each cycle, k is 0,1,2, N-1, N is the number of harmonics, and N is 0,1,2, N-1, x (k);
the formula for calculating the voltage of the permanent magnet motor is specifically,
and U is the voltage of the permanent magnet machine.
In the electrical parameter calculation method of the present invention: the frequency of the generator is 50Hz, the AD sampling chip samples according to 32 points per cycle at intervals, meanwhile, the sampling interval of the voltage of the permanent magnet machine is the same as that of the voltage of the generator and samples along with the voltage of the generator, because the permanent magnet machine rotates along with the generator coaxially, the frequency and the generator keep unchanged ratio, according to the sampling 32 points per cycle of 50Hz and the Nyquist sampling theorem, the sampling frequency needs to be 2 times higher than the highest frequency, the AC voltage waveform with the highest calculation frequency of 50 multiplied by 32 divided by 2 divided by 800Hz can be deduced, the sampling points and harmonic times are adjusted according to the frequency of the permanent magnet machine and the frequency of the generator, the number of sampling points under a certain frequency can be always found, and the harmonic times can be calculated to calculate.
In the electrical parameter calculation method of the present invention: the sine value and the cosine value of each harmonic can be stored in a table in advance, FFT calculation functions (harmonic calculation formulas) corresponding to all rated frequencies in the table 1 are stored, a sampling point is set to be a maximum value of 96 points, once the generator rotates, the frequency of the generator and the frequency of the permanent magnet machine can be monitored, the sampling point is adjusted according to the frequency ratio of the permanent magnet machine, the corresponding FFT functions are called to calculate voltage, the voltage of the permanent magnet machine is compensated according to the frequency of the permanent magnet machine, and the real voltage of the permanent magnet machine can be obtained. Meanwhile, if the specific rated frequency of the permanent magnet machine is known in advance, the rated frequency of the permanent magnet machine can be set, so that the rated frequency of the permanent magnet machine is not required to be monitored when the machine is started every time.
According to the above measurement method, the actual excitation system test is performed, and the specific test data is shown in table 2.
TABLE 2
The result of the test and the field unit test data shows that the electrical parameter calculation method has extremely high test precision and still meets the measurement precision of 0.2 percent under the maximum frequency of 500 Hz. The electrical parameter calculation method of the invention can completely meet the requirement of quick measurement response of the excitation system.
Based on the electric parameter calculation method of the brushless generator set, the invention also provides an electric parameter calculation system of the brushless generator set.
As shown in fig. 6, an electrical parameter calculation system of a brushless generator set, the brushless generator set comprising a generator and a permanent magnet machine, the electrical parameter calculation system being applied to the electrical parameter calculation method of the brushless generator set as described above, the electrical parameter comprising a permanent magnet machine voltage, the electrical parameter calculation system comprising the following modules,
the corresponding relation table establishing module is used for establishing a corresponding relation table of the frequency of the permanent magnet machine, the sampling point number of each cycle and the harmonic frequency in advance according to the coaxial rotation characteristic of the permanent magnet machine and the generator;
the frequency measurement module is used for measuring the frequency of the permanent magnet machine and the frequency of the generator;
the sampling point adjusting module is used for adjusting the sampling period of alternating current sampling of the voltage of the permanent magnet machine according to the ratio of the frequency of the permanent magnet machine to the frequency of the generator based on the corresponding relation table, so that the sampling points of the permanent magnet machine under the alternating current sampling of each cycle are the same as the sampling points under the corresponding frequency of the permanent magnet machine in the corresponding relation table;
the permanent magnet machine voltage sampling module is used for carrying out alternating current sampling on the permanent magnet machine voltage according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle sampling point;
and the permanent magnet machine voltage calculation module is used for calculating the permanent magnet machine voltage according to the voltage sampling value of the permanent magnet machine at each sampling point of the cycle and the sampling point number and the harmonic frequency of the permanent magnet machine at the corresponding frequency in the corresponding relation table based on a harmonic calculation formula of Fourier transform.
Based on the electric parameter calculation method of the brushless generator set, the invention also provides a computer storage medium.
A computer storage medium comprising a memory and a computer program stored in the memory, the computer program, when executed, implementing a method of calculating an electrical parameter of a brushless generator set as described above.
The invention relates to a method, a system and a storage medium for calculating electric parameters of a brushless generator set, wherein a permanent magnet machine and a generator rotate coaxially, the frequency of the generator and the frequency of the permanent magnet machine always keep the same ratio, under the condition of not paying attention to the rated frequency of the permanent magnet machine, the number of sampling points is selected in a self-adaptive manner according to the ratio of the frequency of the permanent magnet machine to the frequency of the generator, the voltage of the permanent magnet machine is accurately and quickly calculated according to the frequency of the permanent magnet machine, and the method, the system and the storage; therefore, the invention can monitor the voltage of the permanent magnet machine on line with high precision, detect whether the output voltage of the permanent magnet machine is normal or not in real time, judge the fault and alarm.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A method for calculating electrical parameters of a brushless generator set, the brushless generator set comprising a generator and a permanent magnet machine, is characterized in that: the electrical parameter comprises a permanent magnet motor voltage, the electrical parameter calculation method comprises the following steps,
according to the coaxial rotation characteristic of the permanent magnet machine and the generator, a corresponding relation table of the frequency of the permanent magnet machine, the sampling point number of each cycle and the harmonic frequency is established in advance;
measuring the frequency of the permanent magnet machine, and measuring the frequency of the generator;
based on the corresponding relation table, adjusting the sampling period of AC sampling of the voltage of the permanent magnet machine according to the ratio of the frequency of the permanent magnet machine to the frequency of the generator, so that the number of sampling points of the permanent magnet machine under AC sampling of each cycle is the same as the number of sampling points under the frequency of the corresponding permanent magnet machine in the corresponding relation table;
carrying out alternating current sampling on the voltage of the permanent magnet machine according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle sampling point;
and calculating the voltage of the permanent magnet machine according to the voltage sampling value of the permanent magnet machine at each sampling point of the cycle and the sampling point number and the harmonic frequency of the permanent magnet machine corresponding to the frequency in the corresponding relation table based on a harmonic calculation formula of Fourier transform.
2. The method of calculating electrical parameters of a brushless generator set of claim 1, wherein: the specific steps for measuring the frequency of the permanent magnet machine are,
the output of the permanent magnet machine sequentially passes through a first voltage transformer and a first second-order low-pass filter to obtain an alternating voltage signal of the permanent magnet machine;
converting an alternating-current voltage signal of the permanent magnet machine into a first symmetrical square wave signal with the amplitude of +/-12V by using a first zero-crossing hysteresis comparison circuit;
converting the first square wave signal into a second symmetrical square wave signal of 0-3.3V by using a first pulse amplitude limiting circuit;
capturing a first interval count value of two continuous pulse rising edges of the second symmetrical square wave signal by using a CPU (Central processing Unit), and calculating the frequency of the permanent magnet machine according to the system clock frequency of the CPU and the first interval count value; the calculation formula of the frequency of the permanent magnet machine is as follows,
wherein f istIs the permanent magnet machine frequency, F is the system clock frequency of the CPU, t1Is the first interval count value.
3. The method of calculating electrical parameters of a brushless generator set of claim 2, wherein: the electrical parameter calculation method further comprises the steps of,
calculating the amplification factor of the permanent magnet voltage under alternating current sampling according to the permanent magnet frequency and the element parameters in the first second-order low-pass filter, and compensating the permanent magnet voltage according to the amplification factor to obtain the actual value of the permanent magnet voltage; the actual value of the permanent magnet motor voltage is calculated according to the formula,
wherein, URMSAnd U is the voltage of the permanent magnet machine, and A is the amplification factor.
4. The method of calculating electrical parameters of a brushless generator set of claim 3, wherein: the method comprises the following steps of carrying out alternating current sampling on the voltage of the permanent magnet machine according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle sampling point,
and inputting the alternating voltage signal of the permanent magnet machine into an AD sampling chip, and carrying out alternating current sampling on the voltage of the permanent magnet machine by the AD sampling chip according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle of sampling point.
5. The method of calculating electrical parameters of a brushless generator set of claim 1, wherein: the specific steps for measuring the frequency of the generator are,
outputting the PT secondary voltage special for generator excitation sequentially through a second voltage transformer and a second-order low-pass filter to obtain a first alternating voltage signal of the generator;
converting the first alternating voltage signal of the generator into a third symmetrical square wave signal with the amplitude of +/-12V by using a second zero-crossing hysteresis comparison circuit;
converting the third square wave signal into a fourth symmetrical square wave signal of 0-3.3V by using a second pulse amplitude limiting circuit;
capturing a second interval count value of two continuous pulse rising edges of the fourth symmetrical square wave signal by using a CPU (Central processing Unit), and calculating the frequency of the generator according to the system clock frequency of the CPU and the second interval count value; the formula for calculating the frequency of the generator is,
wherein f isgIs the generator frequency, F is the system clock frequency of the CPU, t2Is the second interval count value.
6. The method of calculating electrical parameters of a brushless generator set of claim 1, wherein: the electrical parameters also comprise rated frequency of the permanent magnet machine; the electrical parameter calculation method further comprises the steps of,
calculating the rated frequency of the permanent magnet machine according to the rated frequency of the generator, the frequency of the generator and the frequency of the permanent magnet machine;
the calculation formula of the rated frequency of the permanent magnet machine is as follows,
wherein f iseFor the rated frequency, f, of the permanent magnet machinetIs the frequency of said permanent magnet machine, fgFor the generator frequency, fHThe rated frequency of the generator.
7. The method of calculating electrical parameters of a brushless generator set of claim 5, wherein: the electrical parameter further comprises a generator voltage; the electrical parameter calculation method further comprises the steps of,
outputting the PT secondary voltage special for generator excitation sequentially through a second voltage transformer and a first-order low-pass filter to obtain a second alternating voltage signal of the generator;
inputting a second alternating voltage signal of the generator into an AD sampling chip, wherein the AD sampling chip performs alternating current sampling on the voltage of the generator according to the sampling period to obtain a voltage sampling value of the generator at each cycle of wave sampling point;
calculating the voltage of the generator according to a voltage sampling value of the generator at each cycle sampling point;
and the sampling interval of the voltage of the permanent magnet motor is the same as that of the voltage of the generator.
8. Method for calculating electrical parameters of a brushless generator set according to any of claims 1-7, characterized in that: the harmonic calculation formula based on fourier transform is specifically,
wherein, anIs the real part of the nth harmonic, bnThe voltage sampling value of the permanent magnet machine at the kth sampling point of each cycle is N, N is the number of sampling points of each cycle, k is 0,1,2, N-1, N is the number of harmonics, and N is 0,1,2, N-1, x (k);
the formula for calculating the voltage of the permanent magnet motor is specifically,
and U is the voltage of the permanent magnet machine.
9. An electrical parameter calculation system of a brushless generator set, the brushless generator set comprising a generator and a permanent magnet machine, characterized in that: the electrical parameter calculation system is applied to the electrical parameter calculation method of the brushless generator set according to any one of claims 1 to 8, the electrical parameter comprises permanent magnet motor voltage, the electrical parameter calculation system comprises the following modules,
the corresponding relation table establishing module is used for establishing a corresponding relation table of the frequency of the permanent magnet machine, the sampling point number of each cycle and the harmonic frequency in advance according to the coaxial rotation characteristic of the permanent magnet machine and the generator;
the frequency measurement module is used for measuring the frequency of the permanent magnet machine and the frequency of the generator;
the sampling point adjusting module is used for adjusting the sampling period of alternating current sampling of the voltage of the permanent magnet machine according to the ratio of the frequency of the permanent magnet machine to the frequency of the generator based on the corresponding relation table, so that the sampling points of the permanent magnet machine under the alternating current sampling of each cycle are the same as the sampling points under the corresponding frequency of the permanent magnet machine in the corresponding relation table;
the permanent magnet machine voltage sampling module is used for carrying out alternating current sampling on the permanent magnet machine voltage according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle sampling point;
and the permanent magnet machine voltage calculation module is used for calculating the permanent magnet machine voltage according to the voltage sampling value of the permanent magnet machine at each sampling point of the cycle and the sampling point number and the harmonic frequency of the permanent magnet machine at the corresponding frequency in the corresponding relation table based on a harmonic calculation formula of Fourier transform.
10. A computer storage medium, characterized in that: comprising a memory and a computer program stored in said memory, which when executed, implements a method of calculating an electrical parameter of a brushless generator set according to any of claims 1-8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110115943.9A CN112798957A (en) | 2021-01-28 | 2021-01-28 | Electric parameter calculation method and system of brushless generator set and storage medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110115943.9A CN112798957A (en) | 2021-01-28 | 2021-01-28 | Electric parameter calculation method and system of brushless generator set and storage medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112798957A true CN112798957A (en) | 2021-05-14 |
Family
ID=75812414
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110115943.9A Pending CN112798957A (en) | 2021-01-28 | 2021-01-28 | Electric parameter calculation method and system of brushless generator set and storage medium |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112798957A (en) |
-
2021
- 2021-01-28 CN CN202110115943.9A patent/CN112798957A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Chauhan et al. | A novel distribution-level phasor estimation algorithm using empirical wavelet transform | |
| EP2113994A2 (en) | Systems and methods for reducing distortion in a power source using an active harmonics filter | |
| Reza et al. | Single-phase grid voltage frequency estimation using teager energy operator-based technique | |
| Sadinezhad et al. | Slow sampling online optimization approach to estimate power system frequency | |
| CN110618338B (en) | Electric energy quality transient measurement method, device and equipment | |
| CN103197130A (en) | Power grid voltage ZCP (Zero Crossing Point) detecting method and device | |
| Karimi-Ghartemani et al. | A signal processing module for power system applications | |
| Florio et al. | Voltage sag detection based on rectified voltage processing | |
| CN112798957A (en) | Electric parameter calculation method and system of brushless generator set and storage medium | |
| CN102841314A (en) | Temperature rise test method and system for electrically excited synchronous motors | |
| Mejia-Barron et al. | A scheme based on PMU data for power quality disturbances monitoring | |
| Cataliotti et al. | A time-domain strategy for the measurement of IEEE Standard 1459-2000 power quantities in nonsinusoidal three-phase and single-phase systems | |
| Gutierrez et al. | Power quality in grid-connected wind turbines | |
| CN214895681U (en) | Electric parameter detection circuit of brushless generator set | |
| Elsahwi et al. | A digital frequency adaptive synchronization unit for on-and off-grid systems | |
| Mangalekar et al. | Electric motor power quality assessment using LabVIEW based smart power analyzer | |
| CN109307800A (en) | A kind of total harmonic detecting method of power grid | |
| CN109193749B (en) | Harmonic generation device based on recursive discrete Fourier transform and control method | |
| Cataliotti et al. | A new phase locked loop strategy for power quality instruments synchronisation | |
| Najafi et al. | A D-STATCOM based on Goertzel algorithm for sag detection and a novel current mode controller | |
| Chao et al. | Shunt Active Power Filter System Design for Inter-harmonic | |
| Zheng et al. | Frequency-domian current control of harmonic current injection system for power capacitor | |
| JP2004198273A (en) | Quality check method for ac power input into power converter | |
| CN117630583B (en) | Control method of power distribution network capacitance current and ground resistance detection device | |
| Wei et al. | A fast PLL method for power electronic systems connected to distorted grids |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |