CN114019224A - Aviation alternating current parameter testing method - Google Patents
Aviation alternating current parameter testing method Download PDFInfo
- Publication number
- CN114019224A CN114019224A CN202111107457.9A CN202111107457A CN114019224A CN 114019224 A CN114019224 A CN 114019224A CN 202111107457 A CN202111107457 A CN 202111107457A CN 114019224 A CN114019224 A CN 114019224A
- Authority
- CN
- China
- Prior art keywords
- frequency
- signal
- voltage
- current
- digital
- 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
- 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
-
- 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)
- Measurement Of Current Or Voltage (AREA)
Abstract
The invention relates to the technical field of electronic measurement, in particular to an aviation alternating current parameter testing method, which comprises the following specific steps: s1, converting the high-voltage alternating current signal to be detected into a voltage signal u1 by the transformer, and converting the current signal to be detected into a current signal i1 by the current sensor; s2, carrying out signal conditioning and amplification to obtain u2 and i 2; s3, detecting zero crossing; s4, multiplying the frequency of the signal to obtain a sampling clock; s5, sampling the voltage and the current at the same time; s6, transmitting the sampled data to a rear-stage CPU for calculation to obtain a parameter result; the digital frequency multiplier generated by a digital circuit in the FPGA avoids the defects of poor stability, low consistency and low maximum output frequency when an analog phase-locked loop is used for frequency multiplication, generates a square wave signal with the frequency N times of the frequency of a power supply to be tested, can change along with the change of the frequency of input voltage, realizes real-time tracking, avoids the phenomenon of frequency spectrum leakage, and can be applied to the field of 400Hz aviation power supply testing.
Description
Technical Field
The invention relates to the technical field of electronic measurement, in particular to an aviation alternating current parameter testing method.
Background
In power electronic systems, voltage effective value, current effective value, active power, reactive power, apparent power, power factor and the like of alternating current are all very important parameters, and therefore, measurement of alternating current parameters is also an important research subject in the field of electronic measurement.
In order to realize the measurement of the ac parameters, one solution in the prior art is to use an application-specific integrated circuit chip, such as ADE78XX chip of the american AD company and AT73C500 chip of the american ATMEL company. However, the special chips use a fixed sampling rate, and can only be applied to the occasions with the alternating current frequency of 50Hz or 60Hz, and if the special chips are applied to the 400Hz/115V alternating current test used in the aviation field with large frequency variation, the error is large.
For the parameter test of 400Hz/115V aviation power supply, the prior art mainly measures the frequency f of an alternating current signal by using a timer, samples the alternating current signal by taking integral multiple of f as sampling frequency to obtain the instantaneous voltage/current value of n sampling points, and then obtains the required parameters by calculation. However, the calculated sampling length has hysteresis, and when the frequency is unstable, the spectrum leakage phenomenon is likely to occur, and the error is still large.
For the situation that the frequency is changed, the frequency multiplication can be effectively finished by using the phase-locked loop circuit, for example, an analog phase-locked loop chip 74HC4046 or CD4046, however, the chip is designed by using an analog circuit, the design of filter parameters therein is very complicated, the consistency is poor, the defects of complex circuit, easy aging of elements, working point drift and the like exist, and meanwhile, it is difficult to design an analog phase-locked loop circuit to be suitable for the situation that the frequency change range is large (for example, 30Hz-800 Hz).
Disclosure of Invention
In order to solve the problems, the invention provides an aviation alternating current parameter testing method.
An aviation alternating current parameter testing method comprises the following specific steps:
s1, converting the high-voltage alternating current signal to be detected into a voltage signal u1 by the transformer, and converting the current signal to be detected into a current signal i1 by the current sensor;
s2, signal conditioning and amplification to obtain u2 and i 2: the signal conditioning circuit amplifies and conditions the converted voltage signal u1 and the current signal i1 by using an operational amplifier to obtain u2 and i2 respectively, so that the signal amplitudes of u2 and i2 are in the conversion range of the analog-to-digital converter;
s3, zero crossing detection: processing the voltage signal u2 by using a zero-crossing detection circuit to obtain a square wave signal u3, wherein the frequency of the square wave signal u3 is f;
s4, obtaining a sampling clock by signal frequency multiplication: connecting the square wave signal u3 to an FPGA (field programmable gate array), and constructing a digital frequency multiplier in the FPGA to obtain a square wave signal clk with the frequency of Nf;
s5, sampling the voltage and current simultaneously: the voltage signal u and the current signal i are converted into digital signals by using two analog-to-digital converters, clock signals of the two analog-to-digital converters are generated by a digital frequency multiplier in the FPGA, the frequency is Nf, control signals of the two analog-to-digital converters are connected and are all given by the FPGA, and sampling moments of the two analog-to-digital converters are completely the same, namely, the voltage and the current are sampled simultaneously.
S6, transmitting the sampled data to a rear-stage CPU for calculation to obtain a parameter result: in an alternating voltage period, each analog-to-digital converter samples N points at equal intervals, and the FPGA transmits the acquired data to a back-stage CPU.
The current sensor of step S1 may be a hall current sensor or a rogowski coil current sensor.
In the step S3, the frequency is N times of the frequency of the square wave signal u2, and for convenience of calculation, N is an integer power of 2, such as 128, 256, and 512 classes.
In step S5, the CPU calculates the voltage effective value, the current effective value, the active power, the reactive power, the apparent power, and the power factor parameters according to the formula.
The invention has the beneficial effects that: the digital frequency multiplier generated by a digital circuit in the FPGA avoids the defects of poor stability, low consistency and low maximum output frequency when an analog phase-locked loop is used for frequency multiplication, generates a square wave signal with the frequency N times of the frequency of a power supply to be tested, can change along with the change of the frequency of input voltage, realizes real-time tracking, avoids the phenomenon of frequency spectrum leakage, and can be applied to the field of 400Hz aviation power supply testing.
Drawings
The invention is further illustrated with reference to the following figures and examples.
FIG. 1 is a circuit block diagram of the present invention;
FIG. 2 is a diagram of an embodiment of a zero crossing detection circuit according to the present invention;
FIG. 3 is a signal waveform diagram of the present invention;
FIG. 4 is a schematic diagram of a digital frequency multiplier of the present invention;
FIG. 5 is a schematic view of the flow structure of the present invention.
Detailed Description
In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further explained below.
As shown in fig. 1 to 5, a method for testing aviation alternating current parameters comprises the following specific steps:
s1, converting the high-voltage alternating current signal to be detected into a voltage signal u1 by the transformer, and converting the current signal to be detected into a current signal i1 by the current sensor;
s2, signal conditioning and amplification to obtain u2 and i 2: the signal conditioning circuit amplifies and conditions the converted voltage signal u1 and the current signal i1 by using an operational amplifier to obtain u2 and i2 respectively, so that the signal amplitudes of u2 and i2 are in the conversion range of the analog-to-digital converter;
s3, zero crossing detection: processing the voltage signal u2 by using a zero-crossing detection circuit to obtain a square wave signal u3, wherein the frequency of the square wave signal u3 is f;
s4, obtaining a sampling clock by signal frequency multiplication: connecting the square wave signal u3 to an FPGA (field programmable gate array), and constructing a digital frequency multiplier in the FPGA to obtain a square wave signal clk with the frequency of Nf;
s5, sampling the voltage and current simultaneously: the voltage signal u and the current signal i are converted into digital signals by using two analog-to-digital converters, clock signals of the two analog-to-digital converters are generated by a digital frequency multiplier in the FPGA, the frequency is Nf, control signals of the two analog-to-digital converters are connected and are all given by the FPGA, and sampling moments of the two analog-to-digital converters are completely the same, namely, the voltage and the current are sampled simultaneously.
S6, transmitting the sampled data to a rear-stage CPU for calculation to obtain a parameter result: in an alternating voltage period, each analog-to-digital converter samples N points at equal intervals, and the FPGA transmits the acquired data to a back-stage CPU.
The digital frequency multiplier generated by a digital circuit in the FPGA avoids the defects of poor stability, low consistency and low maximum output frequency when an analog phase-locked loop is used for frequency multiplication, generates a square wave signal with the frequency N times of the frequency of a power supply to be tested, can change along with the change of the frequency of input voltage, realizes real-time tracking, avoids the phenomenon of frequency spectrum leakage, and can be applied to the field of 400Hz aviation power supply testing.
The current sensor of step S1 may be a hall current sensor or a rogowski coil current sensor.
The sampling clock used by the invention is generated by a digital frequency multiplier in the FPGA, the frequency of the sampling clock is always N times of the alternating voltage to be measured, no calculation delay and no frequency spectrum leakage exist, and the measurement accuracy of the alternating voltage signal in a wide frequency range is high.
The hardware circuit of the invention is simple and reliable, and can be used as an alternating current detection unit alone or transplanted to other complex monitoring systems.
In the step S3, the frequency is N times of the frequency of the square wave signal u2, and for convenience of calculation, N is an integer power of 2, such as 128, 256, and 512 classes.
Fig. 2 is an embodiment of a zero-crossing detection circuit, which is composed of a resistor R1, diodes V1, V2 and a comparator LM393, wherein an alternating-current voltage signal is limited to ± 0.7V by the diodes V1 and V2 after passing through the resistor R1, and then is compared by the LM393 to obtain a square-wave signal.
As shown in fig. 3, a signal waveform diagram of the zero-cross detection circuit and a waveform diagram of the sampling clock are shown, a square wave signal u3 is obtained after an input voltage u2 passes through the zero-cross detection circuit, the square wave signal u3 is input to the FPGA, and a digital frequency multiplier inside the FPGA generates a clock signal clk with N times of frequency.
Fig. 4 shows an example of an implementation of a digital frequency multiplier inside an FPGA, 74297 is a digital phase-locked loop chip of TI corporation, in which functional units can be embedded in the FPGA, and the design of the circuit can be easily realized. The KCLK pin and the I/Dclk pin of 74297 are connected with the internal clock of FPGA; the D/UPN is connected with the XORPD pin; PHASE _ a1 receives an input signal, i.e., u3 in fig. 1; the initial value of the K counter is the initial value of an internal digital wave filter, the carry and borrow pulse time of the K counter can be adjusted by changing the value of the K counter, the capture bandwidth can be narrowed along with the increase of the K value, the locking time can be prolonged, and the anti-interference capability is obviously improved; the IDOUT is connected with an output signal, namely the clock signal in the figure 1, and is used for providing clock signals for the two analog-to-digital converters, and meanwhile, the IDOUT signal is divided by the N frequency divider and then is connected with the PHASE _ B for feeding back a PHASE signal, so that after the PHASE-locked loop is stabilized, the output frequency is N times of the input frequency; the digital phase-locked loop can work at the optimal frequency point by changing the value of the N frequency divider, thereby realizing a wide input frequency range.
In step S5, the CPU calculates the voltage effective value, the current effective value, the active power, the reactive power, the apparent power, and the power factor parameters according to the formula.
The invention provides an alternating current parameter detection method aiming at aviation power parameter testing with large frequency change.
The square wave signal generated by the digital frequency multiplier is used as the clock signal of the two analog-to-digital converters, so that each analog-to-digital converter can sample for N times in one period, and the two analog-to-digital converters sample simultaneously, so that the voltage and current values used for calculation can be generated at the same time, the precision is improved, and the problem that the error is large when the existing scheme is applied to occasions with large frequency change is solved.
The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are merely illustrative of the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (5)
1. An aviation alternating current parameter testing method is characterized in that: the method comprises the following specific steps:
s1, converting the high-voltage alternating current signal to be detected into a voltage signal u1 by the transformer, and converting the current signal to be detected into a current signal i1 by the current sensor;
s2, signal conditioning and amplification to obtain u2 and i 2: the signal conditioning circuit amplifies and conditions the converted voltage signal u1 and the current signal i1 by using an operational amplifier to obtain u2 and i2 respectively, so that the signal amplitudes of u2 and i2 are in the conversion range of the analog-to-digital converter;
s3, zero crossing detection: processing the voltage signal u2 by using a zero-crossing detection circuit to obtain a square wave signal u3, wherein the frequency of the square wave signal u3 is f;
s4, obtaining a sampling clock by signal frequency multiplication: connecting the square wave signal u3 to an FPGA (field programmable gate array), and constructing a digital frequency multiplier in the FPGA to obtain a square wave signal clk with the frequency of Nf;
s5, sampling the voltage and current simultaneously: the voltage signal u and the current signal i are converted into digital signals by using two analog-to-digital converters, clock signals of the two analog-to-digital converters are generated by a digital frequency multiplier in the FPGA, the frequency is Nf, control signals of the two analog-to-digital converters are connected and are all given by the FPGA, and sampling moments of the two analog-to-digital converters are completely the same, namely, the voltage and the current are sampled simultaneously.
S6, transmitting the sampled data to a rear-stage CPU for calculation to obtain a parameter result: in an alternating voltage period, each analog-to-digital converter samples N points at equal intervals, and the FPGA transmits the acquired data to a back-stage CPU.
2. The aviation alternating current parameter testing method according to claim 1, characterized in that: the current sensor of step S1 may be a hall current sensor or a rogowski coil current sensor.
3. The aviation alternating current parameter testing method according to claim 1, characterized in that: in the step S3, the frequency is N times of the frequency of the square wave signal u2, and for convenience of calculation, N is an integer power of 2.
4. The aviation alternating current parameter testing method according to claim 3, characterized in that: in the step S3, the frequency N times the frequency of the square wave signal u2 may be one of 128, 256, and 512.
5. The aviation alternating current parameter testing method according to claim 1, characterized in that: in step S5, the CPU calculates the voltage effective value, the current effective value, the active power, the reactive power, the apparent power, and the power factor parameters according to the formula.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111107457.9A CN114019224A (en) | 2021-09-22 | 2021-09-22 | Aviation alternating current parameter testing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111107457.9A CN114019224A (en) | 2021-09-22 | 2021-09-22 | Aviation alternating current parameter testing method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114019224A true CN114019224A (en) | 2022-02-08 |
Family
ID=80054812
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111107457.9A Pending CN114019224A (en) | 2021-09-22 | 2021-09-22 | Aviation alternating current parameter testing method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114019224A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06207955A (en) * | 1992-11-18 | 1994-07-26 | Mitsubishi Electric Corp | Pi/2 phase shift circuit, reactive energy meter and composite meter employing it |
| CN102565523A (en) * | 2012-01-12 | 2012-07-11 | 上海理工大学 | Current harmonic detection system and working method |
| CN104076710A (en) * | 2014-05-26 | 2014-10-01 | 浙江工业大学 | Electric vehicle V2G monitor |
| CN203909138U (en) * | 2014-06-18 | 2014-10-29 | 中国航天科技集团公司第九研究院第七七一研究所 | General three-phase AC signal synchronous sampling device |
| CN108646138A (en) * | 2018-05-11 | 2018-10-12 | 武汉理工大学 | Network of ship electric energy quality monitoring system based on FPGA and method |
| CN212301717U (en) * | 2020-04-23 | 2021-01-05 | 国网安徽省电力有限公司铜陵供电公司 | Based on DSP + ARM electric energy quality detector |
-
2021
- 2021-09-22 CN CN202111107457.9A patent/CN114019224A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06207955A (en) * | 1992-11-18 | 1994-07-26 | Mitsubishi Electric Corp | Pi/2 phase shift circuit, reactive energy meter and composite meter employing it |
| CN102565523A (en) * | 2012-01-12 | 2012-07-11 | 上海理工大学 | Current harmonic detection system and working method |
| CN104076710A (en) * | 2014-05-26 | 2014-10-01 | 浙江工业大学 | Electric vehicle V2G monitor |
| CN203909138U (en) * | 2014-06-18 | 2014-10-29 | 中国航天科技集团公司第九研究院第七七一研究所 | General three-phase AC signal synchronous sampling device |
| CN108646138A (en) * | 2018-05-11 | 2018-10-12 | 武汉理工大学 | Network of ship electric energy quality monitoring system based on FPGA and method |
| CN212301717U (en) * | 2020-04-23 | 2021-01-05 | 国网安徽省电力有限公司铜陵供电公司 | Based on DSP + ARM electric energy quality detector |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Djokic et al. | Phase measurement of distorted periodic signals based on nonsynchronous digital filtering | |
| de la O Serna et al. | Instantaneous Oscillating Phasor Estimates With Taylor $^ K $-Kalman Filters | |
| CN203909138U (en) | General three-phase AC signal synchronous sampling device | |
| CN103344825A (en) | Electric energy measuring system based on alternating-current sampling | |
| CN105699738A (en) | PWM-based AC signal effective value measurement method | |
| CN113075474A (en) | Electric energy measuring system and method | |
| CN202631654U (en) | Double-channel quasi-synchronization comprehensive electric energy detection network | |
| CN114019224A (en) | Aviation alternating current parameter testing method | |
| KR19990044983A (en) | Effective value converter which can measure the effective value quickly | |
| Mujumdar et al. | Microcontroller based true RMS current measurement under harmonic conditions | |
| Makanjuola et al. | Design and Development of a Microcontroller Based Digital Wattmeter (MIDIWAT) | |
| US9759751B1 (en) | Line cycle correlated spectral analysis for power measurement systems | |
| Bekirov et al. | Real time processing of the phase shift and the frequency by voltage signal conversion into the sequence of rectangular pulses | |
| CN204649825U (en) | Based on the high speed true effective value rectifying system of FPGA | |
| CN111239638B (en) | Method for detecting periodic and random changes of output frequency of alternating current voltage source | |
| Hatsenko et al. | Investigation of the Effect of Harmonic Interference on the Error with Frequency Conversion of Energy Supply Systems on Water Transport Vehicles (short paper). | |
| Simonson et al. | A comparison of power measuring systems | |
| RU214462U1 (en) | POWER FACTOR METER | |
| RU2624413C1 (en) | Quick-response quasi-sinusoidal signal amplitude meter | |
| Kawagoe et al. | A digital system for calibrating active/reactive power and energy meters | |
| CN109884388B (en) | Half-cycle phase-shifting method-based power grid frequency metering and measuring device and method | |
| Salinas et al. | Sampling strategies comparison for high accuracy power measurements | |
| Teren et al. | The design of an analog to digital front-end for frequency domain spectroscopy analyzer | |
| Mahmud et al. | Design and Hardware Implementation of a Digital Wattmeter | |
| Kim et al. | Effect of input bandwidth of a sampler on differential sampling based on a programmable josephson voltage standard |
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 |