A kind of three-phase circuit impedance test system and method
Technical field
The invention belongs to testing impedance technical fields, and in particular to a kind of three-phase circuit impedance test system and side
Method.
Background technique
Distributed power supply system has many advantages, such as high reliablity, is easily achieved modularization and convenient for safeguarding, increasingly by
The high praise and welcome of industry are widely used in spacecraft, naval vessel, communication base station and mainframe computer power supply system.It is being distributed
In formula power supply system, for each equipment by different supplier's independent designs, when design, merely ensures that the stable operation of itself, works as cascade
When at a system, even there is system not since the negative input impedance operator of constant power load often leads to system performance decline
Stabilization.
Impedance stability criterion is widely used in direct current system.When studying space station power, Fred C.Lee
Professor has done a large amount of research work for the analysis of direct current system impedance stability, proposes the side measured in direct current system impedance
There is determining dc point in method direct current system, can directly measurement port impedance, also can use commercialized test and set
The standby port identity to obtain direct current system, such as the Network Analyzer of agilent company.For AC system, due to exchanging end
Voltage, the current signal of mouth are time-varying, therefore dc point is not present, and need to be coordinately transformed, three phase static is sat
Mark system is converted into two-phase rotating coordinate system, that is, needs to measure the input and output impedance of AC system under dq coordinate system.Coordinate becomes
The rotation angle needed using AC system is changed, rotation angle is generally obtained by phaselocked loop, but disturbing signal will affect lock
The precision of phase ring, and then influence the result of measurement.On the other hand, since dq coordinate system is virtual coordinate system, three-phase circuit
Signal analysis and subsequent test can not be directly carried out in this coordinate system.
The stability for studying three-phase circuit be unable to do without the measurement of impedance, therefore study the impedance of three-phase circuit
Test philosophy is of great significance for studying the stability analysis of three-phase circuit.
Summary of the invention
In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is that providing a kind of structure letter
Single, novel design is rationally, realization is convenient, can easily and accurately test the three-phase circuit testing impedance of three-phase alternating current impedance
System.
In order to solve the above technical problems, the technical solution adopted by the present invention is that: a kind of three-phase circuit testing impedance system
System, including sequentially connected disturbing signal injection module, signal processing module and signal amplification module, and with signal processing mould
The signal detection module of the input terminal connection of block, the frequency response measurement module that is connect with the output end of signal processing module and with
The impedance computation module of frequency response measurement module connection;The disturbing signal injection module is for generating for injecting three intersections
Disturbing signal under the dq coordinate system of current circuit, and disturbing signal is transferred to frequency response measurement module and signal processing mould
Block;The signal processing module is used to the disturbing signal under dq coordinate system that disturbing signal injection module exports being converted to abc
Three-phase ac signal, which exports, gives signal amplification module, the power supply voltage signal for being measured by phaselocked loop signal detection module
It is handled to obtain the value for the phase angle theta that dq transformation is used, and the port for being measured signal detection module using dq transformation is rung
Induction signal is under from abc coordinate system transformation to dq coordinate system;The signal amplification module is for disturbing signal processing module output
Dynamic signal injects in three-phase circuit after amplifying;The signal detection module is for measuring power supply voltage signal and abc
Port responses signal under coordinate system, and conditioning is filtered to signal;The frequency response measurement module is used to sit by dq
Disturbing signal and port responses signal under mark system obtain corresponding frequency response and export to impedance computation module;The impedance
Computing module is used to be calculated the impedance of three-phase circuit.
A kind of above-mentioned three-phase circuit impedance test system, the disturbing signal injection module and frequency response measurement
Module is made of Network Analyzer.
A kind of above-mentioned three-phase circuit impedance test system, the signal processing module include FPGA board.
A kind of above-mentioned three-phase circuit impedance test system, the FPGA board are the multi-functional number of NI USB-7845R
According to capture card.
A kind of above-mentioned three-phase circuit impedance test system, the signal amplification module includes power amplifier.
A kind of above-mentioned three-phase circuit impedance test system, the impedance computation module includes computer.
The present invention also provides one kind to be difficult to handle and analyze for signal under dq axis in three-phase circuit testing impedance
This case proposes the AC system testing impedance scheme based on FPGA, and test signal and last survey can be effectively treated
Test result analysis, can easily and accurately test the three-phase circuit impedance detecting method of three-phase alternating current impedance, this method packet
Include following steps:
Step 1: generating disturbing signal by disturbing signal injection module, and disturbing signal is transferred to frequency response measurement
Module and signal processing module;
Step 2: signal processing module calls dq coordinate system to the signal processing module of abc coordinate system, disturbing signal is infused
The disturbing signal entered under the dq coordinate system of module generation is converted to abc three-phase ac signal, then exports and give signal amplification module;
Step 3: the disturbing signal that signal amplification module exports signal processing module injects three-phase alternating current after amplifying
In circuit;
Step 4: signal detection module measurement power supply voltage signal and port responses signal, and tune is filtered to signal
Output is to signal processing module after reason;
Step 5: signal processing module, which is handled to obtain dq to power supply voltage signal by phaselocked loop, converts the phase used
The value of angle θ, then converted port responses signal under from abc coordinate system transformation to dq coordinate system using dq;
Step 6: frequency response measurement module obtains corresponding frequency by disturbing signal under dq axis and port responses signal
Rate is responded and is exported to impedance computation module;
Step 7: generating two different disturbing signals by disturbing signal injection module, eight step 1 are repeated extremely
Step 6, to obtain the corresponding port current of two difference disturbing signals and voltage data group, the impedance computation module root
The impedance of three-phase circuit is calculated according to the corresponding port current of two difference disturbing signals and voltage data group.
Above-mentioned method, the disturbing signal injection module and frequency response measurement module are made of Network Analyzer, institute
Stating signal processing module includes FPGA board, and the signal amplification module includes power amplifier, the impedance computation module packet
Include computer.
Above-mentioned method, Network Analyzer obtains phase by disturbing signal under dq axis and port responses signal in step 6
The frequency response answered simultaneously is stored as Excel file, and computer is according to the corresponding port electricity of two different disturbing signals in step 7
When the impedance of three-phase circuit is calculated in stream and voltage data group, first Excel file is imported in MATLAB software, then benefit
Frequency response data is created as frequency response data model with frd function, then passes through fi tfrd function for frequency response data
The impedance of three-phase circuit is calculated further according to state-space model at state-space model for models fitting.
Above-mentioned method, the expression formula of the state-space model are as follows:
Wherein, Ud1Indicate that the first corresponding port voltage of first disturbing signal responds the component on d axis, Uq1Table
Show that the first corresponding port voltage of first disturbing signal responds the component on q axis, Ud2Indicate second disturbing signal pair
Second of the port voltage answered responds the component on d axis, Uq2Indicate corresponding second of the port voltage of second disturbing signal
Respond the component on q axis, Id1Indicate that the first corresponding port current of first disturbing signal responds the component on d axis,
Iq1Indicate that the first corresponding port current of first disturbing signal responds the component on q axis, Id2Indicate second disturbance letter
Number corresponding second of port current responds the component on d axis, Iq2Indicate corresponding second of the port of second disturbing signal
Component of the current-responsive on q axis;ZddIndicate the impedance of d axis, ZdqIndicate the coupled impedance of d axis and q axis, ZqdIndicate q axis and d
The coupled impedance of axis, ZqqIndicate the impedance of q axis;
The solution of the impedance of three-phase circuit (11) is obtained according to formula (F1) are as follows:
Compared with the prior art, the present invention has the following advantages:
1, three-phase circuit impedance test system of the invention uses modular design, and structure is simple, and design is new
Clever reasonable, it is convenient to realize.
2, three-phase circuit impedance test system of the invention realizes that disturbing signal injects mould using Network Analyzer
Block can inject frequency-swept sine wave, and frequency range, amplitude are all variable, and have signal isolation effect.
3, three-phase circuit impedance test system of the invention realizes disturbing signal injection module using Network Analyzer
With frequency response measurement module, the complete function of Network Analyzer simplifies system structure.
4, three-phase circuit impedance test system of the invention realizes signal processing module, FPGA using FPGA board
Board has visualization interface, and the gain control item of signal is provided on the visualization interface, can adjust and disturb according to demand
The amplitude size of dynamic signal can be realized mutually converting for dq coordinate system signal and abc three-phase ac signal, can on-line control lock
The parameter of phase ring, moreover it is possible to the functions such as variation and signal off-limit alarm of real-time monitoring signal.
5, three-phase circuit impedance detecting method of the invention, for believing under dq axis in three-phase circuit testing impedance
It number is difficult to handle and analyze this case, proposes the AC system testing impedance scheme based on FPGA, test can be effectively treated
Signal and last test result analysis can easily and accurately test three-phase alternating current impedance.
6, the present invention is of great significance for studying the stability analysis of three-phase circuit, and practical, popularization is answered
It is high with value.
In conclusion novel design of the invention is rationally, three-phase alternating current impedance can be easily and accurately tested, for grinding
The stability analysis for studying carefully three-phase circuit is of great significance, practical, and application value is high.
Below by drawings and examples, technical scheme of the present invention will be described in further detail.
Detailed description of the invention
Fig. 1 is the schematic block circuit diagram of three-phase circuit impedance test system of the present invention.
Fig. 2 is the circuit connecting relation schematic diagram of three-phase circuit impedance test system of the present invention specific implementation.
Fig. 3 is the schematic diagram of the visualization interface of FPGA board of the present invention.
Fig. 4 is the method flow block diagram of three-phase circuit impedance detecting method of the present invention.
Fig. 5 A is the impedance Z that the method for the present invention is testedddTest value and theoretical value comparison of wave shape figure.
Fig. 5 B is the impedance Z that the method for the present invention is testeddqTest value and theoretical value comparison of wave shape figure.
Fig. 5 C is the impedance Z that the method for the present invention is testedqdTest value and theoretical value comparison of wave shape figure.
Fig. 5 D is the impedance Z that the method for the present invention is testedqqTest value and theoretical value comparison of wave shape figure.
Description of symbols:
1-disturbing signal injection module;2-signal processing modules;3-signal amplification modules;
4-signal detection modules;5-frequency response measurement modules;6-impedance computation modules;
7-Network Analyzers;8-FPGA boards;9-power amplifiers;
10-computers;11-three-phase circuits.
Specific embodiment
As shown in Figure 1, three-phase circuit impedance test system of the invention, including the injection of sequentially connected disturbing signal
Module 1, signal processing module 2 and signal amplification module 3, and the signal detection being connect with the input terminal of signal processing module 2
It module 4, the frequency response measurement module 5 being connect with the output end of signal processing module 2 and is connect with frequency response measurement module 5
Impedance computation module 6;The disturbing signal injection module 1 is used to generate the dq coordinate system for injecting three-phase circuit 11
Under disturbing signal, and disturbing signal is transferred to frequency response measurement module 5 and signal processing module 2;The signal processing
Module 2 is used to the disturbing signal under dq coordinate system that disturbing signal injection module 1 exports being converted to abc three-phase ac signal defeated
Out to signal amplification module 3, the power supply voltage signal for being measured by phaselocked loop signal detection module 4 is handled to obtain
The value for the phase angle theta that dq transformation is used, and for converting the port responses signal for measuring signal detection module 4 from abc using dq
Under coordinate system transformation to dq coordinate system;The disturbing signal that the signal amplification module 3 is used to export signal processing module 2 carries out
It is injected in three-phase circuit 11 after amplification;The signal detection module 4 is for measuring under power supply voltage signal and abc coordinate system
Port responses signal, and conditioning is filtered to signal;The frequency response measurement module 5 is used for by under dq coordinate system
Disturbing signal and port responses signal obtain corresponding frequency response and export to impedance computation module 6;The impedance computation mould
Block 6 is used to be calculated the impedance of three-phase circuit 11.
In the present embodiment, as shown in Fig. 2, the disturbing signal injection module 1 and frequency response measurement module 5 are by network point
Analyzer 7 is constituted.
When it is implemented, the dq coordinate for being used to inject three-phase circuit 11 that the disturbing signal injection module 1 generates
Disturbing signal under system is voltage signal, and the port responses signal that the signal detection module 4 measures is current responsing signal.
Frequency-swept sine wave can be injected using Network Analyzer 7, frequency range, amplitude are all variable, and have signal
Isolation effect.
In the present embodiment, as shown in Fig. 2, the signal processing module 2 includes FPGA board 8.Preferably, the FPGA plate
Card 8 is NI USB-7845R multifunctional data acquisition card.The FPGA board has visualization interface, as shown in figure 3, visual at this
Change the gain control item for being provided with signal on interface, the amplitude size of disturbing signal can be adjusted according to demand, can be realized dq
Coordinate system signal is mutually converted with abc three-phase ac signal, the parameter of energy on-line control phaselocked loop, moreover it is possible to real-time monitoring signal
Variation and the functions such as signal off-limit alarm.
In the present embodiment, as shown in Fig. 2, the signal amplification module 3 includes power amplifier 9.
In the present embodiment, as shown in Fig. 2, the impedance computation module 6 includes computer 10.
As shown in figure 4,11 impedance detecting method of three-phase circuit of the invention, comprising the following steps:
Step 1: generating disturbing signal by disturbing signal injection module 1, and disturbing signal is transferred to frequency response measurement
Module 5 and signal processing module 2;
Step 2: signal processing module 2 calls dq coordinate system to the signal processing module 2 of abc coordinate system, by disturbing signal
Disturbing signal under the dq coordinate system that injection module 1 generates is converted to abc three-phase ac signal, then exports and give signal amplification module
3;
Step 3: injection three is intersected after the disturbing signal that signal amplification module 3 exports signal processing module 2 amplifies
In current circuit 11;
Step 4: signal detection module 4 measures power supply voltage signal and port responses signal, and tune is filtered to signal
Output is to signal processing module 2 after reason;
Step 5: signal processing module 2 handles power supply voltage signal by phaselocked loop to obtain what dq transformation was used
The value of phase angle theta, then converted port responses signal under from abc coordinate system transformation to dq coordinate system using dq;
Step 6: frequency response measurement module 5 is obtained accordingly by disturbing signal under dq axis and port responses signal
Frequency response is simultaneously exported to impedance computation module 6;
Step 7: generating two different disturbing signals by disturbing signal injection module 1, eight step 1 are repeated extremely
Step 6, to obtain the corresponding port current of two difference disturbing signals and voltage data group, the impedance computation module 6
The impedance of three-phase circuit 11 is calculated according to the corresponding port current of two difference disturbing signals and voltage data group.
In the present embodiment, the disturbing signal injection module 1 and frequency response measurement module 5 are made of Network Analyzer 7,
The signal processing module 2 includes FPGA board 8, and the signal amplification module 3 includes power amplifier 9, the impedance computation
Module 6 includes computer 10.
In the present embodiment, Network Analyzer 7 is obtained by disturbing signal under dq axis and port responses signal in step 6
Corresponding frequency response is simultaneously stored as Excel file, and computer 10 is according to the corresponding end of two difference disturbing signals in step 7
When the impedance of three-phase circuit 11 is calculated in mouth electric current and voltage data group, Excel file is first imported into MATLAB software
In, recycle frd function that frequency response data is created as frequency response data model, then pass through fi tfrd function for frequency
The resistance of three-phase circuit 11 is calculated further according to state-space model at state-space model for response data models fitting
It is anti-.
In the present embodiment, the expression formula of the state-space model are as follows:
Wherein, Ud1Indicate that the first corresponding port voltage of first disturbing signal responds the component on d axis, Uq1Table
Show that the first corresponding port voltage of first disturbing signal responds the component on q axis, Ud2Indicate second disturbing signal pair
Second of the port voltage answered responds the component on d axis, Uq2Indicate corresponding second of the port voltage of second disturbing signal
Respond the component on q axis, Id1Indicate that the first corresponding port current of first disturbing signal responds the component on d axis,
Iq1Indicate that the first corresponding port current of first disturbing signal responds the component on q axis, Id2Indicate second disturbance letter
Number corresponding second of port current responds the component on d axis, Iq2Indicate corresponding second of the port of second disturbing signal
Component of the current-responsive on q axis;ZddIndicate the impedance of d axis, ZdqIndicate the coupled impedance of d axis and q axis, ZqdIndicate q axis and d
The coupled impedance of axis, ZqqIndicate the impedance of q axis;
The solution of the impedance of three-phase circuit 11 is obtained according to formula F 1 are as follows:
The technical effect that can be generated to verify the present invention depicts present invention side by taking three-phase RL lattice network as an example
The test value of the impedance that method is tested and the comparison diagram of theoretical value as shown in figs. 5 a-5d, the impedance Z testeddd、Zdq、
Zqd、ZqqThe impedance value goodness of fit calculated with theory is very high, only in coupling terms Zdq、ZqdLocate test result and notional result exists
Some gaps analyze its error source are as follows: are on the one hand due to Zdq、ZqdAmplitude it is less than normal, another party more sensitive to error
Surface error is introduced during simulation calculation process and parameter identification.
The above is only presently preferred embodiments of the present invention, is not intended to limit the invention in any way, it is all according to the present invention
Technical spirit any simple modification to the above embodiments, change and equivalent structural changes, still fall within skill of the present invention
In the protection scope of art scheme.