CN114384315A - Voltage fluctuation and flicker tester based on FPGA and ARM9 - Google Patents
Voltage fluctuation and flicker tester based on FPGA and ARM9 Download PDFInfo
- Publication number
- CN114384315A CN114384315A CN202210005544.1A CN202210005544A CN114384315A CN 114384315 A CN114384315 A CN 114384315A CN 202210005544 A CN202210005544 A CN 202210005544A CN 114384315 A CN114384315 A CN 114384315A
- Authority
- CN
- China
- Prior art keywords
- fpga
- flicker
- voltage
- value
- arm
- 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
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
The invention takes an embedded ARM9 controller and an FPGA as processing cores, designs a handheld voltage fluctuation and flicker tester, and can simultaneously measure the short-time flicker value of a plurality of paths of alternating voltage signalsP stAnd long time flicker valueP lt. In order to simplify the operation process, the square root mean value operation is carried out once on each half cycle of the voltage, the obtained square root mean value sequence is subjected to fast Fourier transform, the corresponding instantaneous flicker value under each frequency is solved, and the short-time flicker is solved by utilizing a probability large value method. By alternately receiving data in 2 groups of memories in the FPGA and utilizing a ping-pong mode to realize a 32-bit FFT algorithm, the operation speed and the accuracy can be greatly improved. The actual measurement result shows that the calculation precision of the tester for the root mean square value reaches 2%, and the flicker measurement precision reaches 2%. The software and hardware platform can conveniently expand the application of other electric energy quality measurement such as harmonic waves, interharmonic waves and the like, and has better popularization value.
Description
Technical Field
The invention belongs to the technical field of electronic measurement, relates to a monitoring device for power quality, and particularly relates to a voltage fluctuation and flicker tester based on an FPGA (field programmable gate array) and an ARM9 (advanced RISC machine).
Background
With the rapid development of the industry and the national economy of China, the load of a power grid is increased rapidly, and particularly, the proportion of impact and nonlinear loads is increased continuously, so that the power supply voltage fluctuates and flashes, and the power quality of the power grid is seriously influenced. At present, a digital flicker meter based on a flicker measurement principle given by IEC61OOO-3-7 standard is published, but the measurement method is complex and the cost is high. The voltage flicker detection method based on the parallel filters needs to analyze the frequency spectrum and follow the amplitude by adopting 2 parallel filters, so that the realization difficulty is high. The voltage flicker is measured by a square detection method based on a virtual instrument, and a computer is needed for matching, so that handheld or installation application is inconvenient to realize.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a handheld voltage fluctuation and flicker tester which takes an FPGA and an ARM as control cores and combines an FFT algorithm, can measure multi-path voltage fluctuation and flicker values in real time and at high precision, can record and store a voltage square mean root value curve, is convenient to check and analyze, and ensures higher measurement precision.
A voltage fluctuation and flicker tester based on FPGA and ARM9 comprises a signal preprocessing circuit, a synchronous A/D converter, an FPGA and ARM microcontroller system;
4 paths of alternating voltage signals are detected and processed through a signal preprocessing circuit, then are subjected to early-stage operation and AD conversion processing through an FPGA and then are transmitted to an ARM control system for later-stage operation, and the functions of man-machine interaction and network communication are achieved;
the signal preprocessing circuit consists of a voltage transformer, an adjustable amplifying circuit consisting of an analog switch and an operational amplifier, and an RC low-pass filter, converts the measured voltage signal into a signal suitable for the A/D range, and filters high-frequency components;
the FPGA internally comprises 43661 logic units, 2088Kb of block RAM and 401Kb of distributed RAM, and the device provides 218I/O; the FPGA is responsible for controlling the A/D converter to sample, controlling the analog switch to switch the measuring range according to the instruction of the ARM9, sampling the action of the keyboard and transmitting the key codes to the ARM controller;
the core operation of the tester is completed by the FPGA, the calculation of a half-wave effective value and FFT conversion are included, and the operation result and the waveform data are transmitted to the ARM controller for subsequent processing;
the A/D converter has a 4-channel simultaneous sampling function, the sampling rate of the A/D converter is 200KSPS.16 bit precision at most, 2 serial and parallel output modes are provided, an input range of +/-5V or +/-10V is selected for expanding a phase difference measurement function, the A/D converter is connected with the FPGA in a parallel mode, the input range of +/-5V is selected, and data and a control bus of the A/D converter are directly connected with I/O of the FPGA;
the ARM control system has the operation speed of 200MHz, is used as a control core of the system, completes the initialization of an operating system and the distribution of each task, and performs post operation on the FFT result to obtain the final result of voltage fluctuation and flicker.
Further, in the signal preprocessing circuit, a voltage transformer selects 2 mA: the 2mA miniature mutual inductor and the adjustable amplifying circuit are composed of a rail-to-rail integrated operational amplifier and 4 paths of analog switches, 4-gear amplification factors are provided, the measuring range of voltage is widened, and the RC low-pass filtering cutoff frequency is 3000 Hz.
Furthermore, the FPGA and the ARM are connected by adopting a bus interface, and an IP core tool is used for generating a 4KB FIFO by using a block RAM inside the FPGA for transmitting data between the FPGA and the ARM.
Furthermore, an ARM control system is internally provided with a LINUX operating system and a QT graphic file system, supports a TCP/IP network protocol stack, externally expands NAND FLASH memories and has the capacity of 128 MB; the external expansion DRAM chip has the capacity of 16M multiplied by 32 bit; and the external expansion SPI bus FLASH chip stores parameters, and the capacity is 128 KB.
Compared with the prior art, the invention has the beneficial effects that: a handheld voltage fluctuation and flicker tester is designed on an ARM9 platform and an FPGA platform, and the FFT algorithm in the FPGA is used for measuring flicker, so that the device has the advantages of high precision and high speed. The mode of LINUX + QT + FATFS ensures that the ARM is convenient to develop, the graphical interface is friendly, the storage is easy, and the introduction of a network interface is convenient for remote communication and control.
Drawings
Fig. 1 is a hardware configuration diagram in the embodiment of the present invention.
Fig. 2 is a diagram of a network communication interface for connecting the ethernet control chip DP83848YB to implement 10M/100M adaptation in the embodiment of the present invention.
FIG. 3 is a flow chart of flicker calculation in an embodiment of the invention.
Fig. 4 is a block diagram of modules in the FPGA in the embodiment of the present invention.
Detailed Description
The technical scheme of the invention is further explained in detail by combining the drawings in the specification.
A hand-held device is composed of a signal preprocessing circuit, a synchronous A/D converter, an FPGA and an ARM microcontroller system. 4 paths of alternating voltage signals are detected and processed through the signal preprocessing circuit, and then are subjected to early stage operation and AD conversion processing through the FPGA and then are transmitted to the ARM control system for later stage operation, so that the functions of man-machine interaction and network communication are realized.
The signal preprocessing circuit consists of a voltage transformer, an adjustable amplifying circuit consisting of an analog switch and an operational amplifier and an RC low-pass filter, can convert a measured voltage signal into a signal suitable for an A/D range (the system is designed to be minus 5 to plus 5V), and filters high-frequency components. Wherein, the voltage transformer is selected from 2 mA: the 2mA miniature mutual inductor has an adjustable amplification circuit consisting of a rail-to-rail integrated operational amplifier and 4 paths of analog switches, 4 amplification factors are provided, a voltage measurement range is increased (the system design is 0.5-500V), and the RC low-pass filtering cutoff frequency is selected to be 3000 Hz.
The FPGA comprises 43661 logic units in the FPGA, wherein the number of the block RAMs reaches 2088Kb, and the FPGA further comprises a 401Kb distributed RAM, the device can provide 218I/O, the power consumption is only 50% of that of the common FPGA, and the FPGA is suitable for handheld design. The FPGA is responsible for controlling the A/D converter to sample, controlling the analog switch to switch the measuring range according to the instruction of the ARM9, sampling the action of the keyboard and transmitting the key codes to the ARM controller. The core operation of the tester is completed by the FPGA, the half-wave effective value calculation and the FFT conversion are carried out, and the operation result and the waveform data are transmitted to the ARM controller for subsequent processing. The FPGA and the ARM are connected by adopting a bus interface, and an IP core tool is used for generating a 4KB FIFO by using a block RAM in the FPGA for transmitting data between the FPGA and the ARM.
The A/D converter has a 4-channel simultaneous sampling function, the sampling rate of the A/D converter is 200KSPS.16 bit accuracy at most, the A/D converter has 2 serial and parallel output modes, and the selectable +/-5V or +/-10V input range can be used for expanding the phase difference measurement function.
The ARM control system has the running speed of 200MHz and rich user interface functions, is a control core of the system, completes initialization of an operating system and distribution of tasks, and performs post operation on FFT results to obtain final results of voltage fluctuation and flicker. Because the ARM control system needs to be internally provided with a LINUX operating system and a QT graphic file system, needs to support a TCP/IP network protocol stack and has larger requirement on program space, the capacity of the external expansion NAND FLASH memory is 128 MB. And the DRAM chip is externally expanded, and the capacity is 16 Mx 32 bits. And the external expansion SPI bus FLASH chip stores parameters, and the capacity is 128 KB. The invention is further illustrated in detail below with reference to specific examples:
firstly, a standard harmonic signal source is used for providing an input signal to a system, 2-6 harmonics are set to be 2% of fundamental waves, then, square root mean value operation is carried out on voltage every half cycle, fast Fourier transform is carried out on an obtained square root mean value sequence, corresponding instantaneous flicker values under various frequencies are solved, and short-time flicker is solved by a probability large value method. By alternately receiving data in 2 groups of memories in the FPGA and utilizing a ping-pong mode to realize a 32-bit FFT algorithm, the operation speed and the accuracy can be greatly improved.
Firstly, calculating a voltage square root value once per half cycle to obtain a voltage square root value sequence U (N), wherein the system takes N as 1024, and the time span is 1024 × 0.01 as 10.24 s.
In the second step, the FFT operation is performed on the sequence u (n) to obtain discrete spectra, and since the time span is 10.24s, the spectral resolution of u (n) is 0.097656Hz at 1/10.24.
Thirdly, dividing 2 times of the frequency spectrum amplitude corresponding to each frequency by the amplitude of the decomposed direct current component to obtain the voltage fluctuation d under the frequencyiUsing the formula Si＝[d(i)/di]2The instantaneous flicker value S at the frequency can be obtainedi。
Fourth, the corresponding transient flicker S of sequence U (N)iIs equal to the sum of the corresponding instantaneous flicker, S, of each frequency on its frequency spectrumi＝s0.5+s1+s1.5+...+s25。
Fifthly, calculating 60 instantaneous flicker values according to the steps, and solving the P values by sequencing0.1,P1,P3,P10And P50The 5 predetermined values, which are the 99.9%, 99%, 97%, 90% and 50% probability maximum values in the S sequence in the period of time, are substituted into the formula
The short-time flicker value P within 10min can be solvedst。
Sixthly, the steps are carried out for 12 times, 12 short-time flicker values are solved, and a formula is utilized
The long-time flicker P within 2h can be solvedlt。
Examining the result of the FPGA after FFT operation:
the relative error of each harmonic wave and the fundamental wave percentage is less than 2 percent through calculation. Comparing the measured root mean square value with the given value, the error is less than 2%. The analysis shows that the error is caused by signal source error, A/D sampling error, and rounding error in FFT operation. The voltage fluctuation and flicker tester is used for actually measuring 380V distribution network in school area, and the test result shows that the short-time flicker value PstMinimum value of 0.096, maximum value of 0.473, long-term flicker value PltIs 0.178, well below the national standard limit of 1.0. The results are more consistent with the actual situation in the school zone.
The above description is only a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above embodiment, but equivalent modifications or changes made by those skilled in the art according to the present disclosure should be included in the scope of the present invention as set forth in the appended claims.
Claims (4)
1. The utility model provides a voltage fluctuation and flicker tester based on FPGA and ARM9, includes signal preprocessing circuit, synchronous AD converter, FPGA and ARM microcontroller system, its characterized in that:
the signal preprocessing circuit detects and processes 4 paths of alternating voltage signals, and then the signals are subjected to early-stage operation and AD conversion processing through the FPGA and then are transmitted to the ARM control system for later-stage operation to obtain a final operation result, so that the man-machine interaction and network communication functions are realized;
the signal preprocessing circuit consists of a voltage transformer, an adjustable amplifying circuit consisting of an analog switch and an operational amplifier, and an RC low-pass filter, converts the measured voltage signal into a signal suitable for the A/D range, and filters high-frequency components;
the FPGA internally comprises 43661 logic units, 2088Kb of block RAM and 401Kb of distributed RAM, and the device provides 218I/O; the FPGA is responsible for controlling the A/D converter to sample, controlling the analog switch to switch the measuring range according to the instruction of the ARM9, sampling the action of the keyboard and transmitting the key codes to the ARM controller;
the core operation of the tester is completed by the FPGA, the calculation of a half-wave effective value and FFT conversion are included, and the operation result and the waveform data are transmitted to the ARM controller for subsequent processing;
the A/D converter has a 4-channel simultaneous sampling function, the sampling rate of the A/D converter is 200KSPS.16 bit precision at most, 2 serial and parallel output modes are provided, an input range of +/-5V or +/-10V is selected for expanding a phase difference measurement function, the A/D converter is connected with the FPGA in a parallel mode, the input range of +/-5V is selected, and data and a control bus of the A/D converter are directly connected with I/O of the FPGA;
the ARM control system has the operation speed of 200MHz, is used as a control core of the system, completes the initialization of an operating system and the distribution of each task, and performs post operation on the FFT result to obtain the final result of voltage fluctuation and flicker.
2. The voltage fluctuation and flicker tester based on the FPGA and the ARM9 of claim 1, wherein: in the signal preprocessing circuit, a voltage transformer selects 2 mA: the 2mA miniature mutual inductor and the adjustable amplifying circuit are composed of a rail-to-rail integrated operational amplifier and 4 paths of analog switches, 4-gear amplification factors are provided, the measuring range of voltage is widened, and the RC low-pass filtering cutoff frequency is 3000 Hz.
3. The voltage fluctuation and flicker tester based on the FPGA and the ARM9 of claim 1, wherein: the FPGA and the ARM are connected by adopting a bus interface, and an IP core tool is used for generating a 4KB FIFO by using a block RAM in the FPGA for transmitting data between the FPGA and the ARM.
4. The voltage fluctuation and flicker tester based on the FPGA and the ARM9 of claim 1, wherein: the ARM control system is internally provided with a LINUX operating system and a QT graphic file system, supports a TCP/IP network protocol stack, externally expands NAND FLASH memories and has the capacity of 128 MB; the external expansion DRAM chip has the capacity of 16M multiplied by 32 bit; and the external expansion SPI bus FLASH chip stores parameters, and the capacity is 128 KB.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210005544.1A CN114384315A (en) | 2022-01-04 | 2022-01-04 | Voltage fluctuation and flicker tester based on FPGA and ARM9 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210005544.1A CN114384315A (en) | 2022-01-04 | 2022-01-04 | Voltage fluctuation and flicker tester based on FPGA and ARM9 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114384315A true CN114384315A (en) | 2022-04-22 |
Family
ID=81198986
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210005544.1A Pending CN114384315A (en) | 2022-01-04 | 2022-01-04 | Voltage fluctuation and flicker tester based on FPGA and ARM9 |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114384315A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116593757A (en) * | 2023-07-17 | 2023-08-15 | 济南巧步思仪器仪表有限公司 | Alternating current ratio measuring method, system and digital alternating current comparator |
-
2022
- 2022-01-04 CN CN202210005544.1A patent/CN114384315A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116593757A (en) * | 2023-07-17 | 2023-08-15 | 济南巧步思仪器仪表有限公司 | Alternating current ratio measuring method, system and digital alternating current comparator |
| CN116593757B (en) * | 2023-07-17 | 2023-11-03 | 济南巧步思仪器仪表有限公司 | Alternating current ratio measuring method, system and digital alternating current comparator |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101907697B (en) | Dynamic property tester of electric energy meter | |
| CN106226723B (en) | Electric energy metering simulation analysis system and method for complex nonlinear load environment | |
| CN105449241A (en) | Online electrochemical impedance spectroscopy detecting system and method of fuel cell | |
| CN103926456A (en) | Flicker value calculation method based on improved FFT and inverter | |
| CN108318852B (en) | Square wave influence test method for intelligent electric energy meter | |
| CN103278686B (en) | A kind of frequency analysis filtering system and intelligent selection harmonic detecting method | |
| CN103926462B (en) | Rapid harmonic wave analyzing method and device of power system | |
| CN103529294A (en) | HHT (Hilbert-Huang Transform)-based harmonic detection system and method for grid-connected inverter of photovoltaic system | |
| CN104316894A (en) | Simulation and calibration method for practical running environment of electric energy meter | |
| CN114384315A (en) | Voltage fluctuation and flicker tester based on FPGA and ARM9 | |
| CN106501755A (en) | A kind of intelligent electric energy meter dynamic error measuring method based on dynamic load model | |
| CN207164236U (en) | Intelligent substation metering secondary metering device composition error off-line measurement system | |
| CN203012023U (en) | A LCR tester | |
| CN212622380U (en) | Automatic range measuring device for electrochemical workstation | |
| CN101303402A (en) | Method for measuring base wave and full power electric energy meter field error | |
| CN114545068A (en) | Portable 10kV three-phase broadband power standard equipment | |
| CN201653613U (en) | Torque detection device for torsional spring | |
| CN201327505Y (en) | Three-phase electrical parameter signal measuring and processing system | |
| CN203838329U (en) | Power consumption tester for voltage line of electric energy meter | |
| CN207181515U (en) | A kind of transformer station's over-voltage monitoring system based on wireless collection technology | |
| CN204855583U (en) | Transient state of accurate heavy current rises and flows generating device | |
| CN204613383U (en) | Earth resistance tester calibration equipment | |
| CN206930688U (en) | A kind of dynamic distortion power source based on high speed DMA fitting | |
| CN112181039A (en) | Direct current standard power source with ripple superposition based on DMA and programmable time base | |
| CN107422156B (en) | Dynamic distortion power source based on high-speed DMA fitting |
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 |