Measuring device for source side impedance of power supply system

Abstract

The utility model provides a measuring device for source-side impedance of a power supply system, relates to the technical field of power supply system design, and is used for improving the measuring accuracy of the source-side impedance of the power supply system. The measuring device comprises a main working circuit, a sampling circuit and a disturbance generating device, wherein the main working circuit comprises source equipment and load equipment; the source equipment is connected with the load equipment, and the impedance of the source equipment is lower than that of the load equipment; the disturbance generation device is arranged between the source equipment and the load equipment, and the disturbance generation device is used for setting harmonic injection parameters and injecting voltage disturbance signals with different frequencies into the main working circuit according to the harmonic injection parameters; and the sampling circuit is arranged between the load equipment and the disturbance generation device and is used for acquiring voltage and current between the load equipment and the disturbance generation device within a preset time of injecting the voltage disturbance signal and transmitting the acquired voltage and current to the disturbance generation device.

Description

TECHNICAL FIELD

[0001] The utility model relates to power system design technical field especially relates to a kind of measuring device of power system source side impedance. BACKGROUND

[0002] With the development and application of more electric and all-electric aircraft, more and more power electronic devices are applied to aircraft power systems. Due to the highly nonlinear time-varying characteristics of power electronic devices, the power system is prone to stability problems. The method commonly used for power system stability analysis is impedance-based stability analysis, which can determine system stability by measuring the output impedance of the power supply side and the input impedance of the load side.

[0003] Currently, the commonly used measurement method for device impedance is series injection, which directly connects the disturbance signal to the circuit under test, and then calculates the impedance values at different frequencies by sampling the port voltage and current of the object under test. Since it is series injection, most of the disturbance signal flows to the load part with high impedance. Therefore, when a generator with small self-impedance is connected in series with a load with high impedance, the disturbance voltage signal generated is small, and it is usually difficult to collect the corresponding response signal when directly measuring the series disturbance signal, and a large measurement error will be generated. SUMMARY

[0004] The embodiment of the application provides a kind of measuring device of power system source side impedance, for improving the measurement accuracy of power system source side impedance.

[0005] The embodiment of the utility model provides a kind of measuring device of power system source side impedance, the measuring device includes: main working circuit, sampling circuit, disturbance generating device, the main working circuit includes source equipment and load equipment;

[0006] The source equipment and the load equipment are connected, and the impedance of the source equipment is lower than the impedance of the load equipment;

[0007] The disturbance generating device is arranged between the source equipment and the load equipment, and the disturbance generating device is used to set harmonic injection parameters and inject voltage disturbance signals of different frequencies into the main working circuit according to the harmonic injection parameters;

[0008] The sampling circuit is arranged between the load equipment and the disturbance generating device, and is used to collect the voltage and current between the load equipment and the disturbance generating device within a predetermined time of injecting the voltage disturbance signal, and transmit the collected voltage and current to the disturbance generating device.

[0009] In an optional embodiment, the disturbance generating device comprises: a host computer, a frequency response analyzer, an excitation small signal generating module, a linear amplifier unit, and an isolation transformer connected in sequence.

[0010] The isolation transformer is arranged between the source device and the load device, and the host computer is configured to set a harmonic injection parameter and inject voltage disturbance signals of different frequencies into the main working circuit through the isolation transformer according to the harmonic injection parameter.

[0011] In an optional embodiment, the sampling circuit is connected to the frequency response analyzer and configured to transmit the collected voltage and current between the load device and the disturbance generating device to the frequency response analyzer.

[0012] In an optional embodiment, the source device is a three-phase motor circuit, and the load device is composed of three parallel resistors.

[0013] In an optional embodiment, each of the three-phase motor circuits is connected in series with a resistor in the load device.

[0014] In an optional embodiment, the sampling circuit is configured to collect a-phase current I a , b-phase current I b , and ab-phase voltage Δu ab and bc-phase voltage Δu bc in the three-phase motor circuit.

[0015] In an optional embodiment, the host computer is further configured to calculate the impedance of the source device according to the collected voltage and current.

[0016] The utility model provides a kind of power system source side impedance measuring device, the measuring device includes: main working circuit, sampling circuit, disturbance generating device, main working circuit includes source equipment and load equipment. Among them, the source equipment is connected with the load equipment, and the impedance of the source equipment is lower than the impedance of the load equipment;The disturbance generating device is arranged between the source equipment and the load equipment, and the disturbance generating device is used to set harmonic injection parameter, and different frequency voltage disturbance signal is injected into the main working circuit according to the harmonic injection parameter;Sampling circuit is arranged between the load equipment and the disturbance generating device, for collecting the voltage and current between the load equipment and the disturbance generating device within the predetermined time of injecting the voltage disturbance signal, and the collected voltage and current are transmitted to the disturbance generating device.The disturbance generating device of the embodiment controls the harmonic injection parameter of different frequency to be exported, and then the disturbance signal corresponding to the harmonic injection parameter is injected into the main working circuit, and the disturbance signal injected will generate disturbance response consistent with the frequency of the disturbance signal injected in the main working circuit, and the voltage and circuit collected in the sampling circuit can calculate the source side impedance of the power system. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 A kind of power system source side impedance measuring device provided for the present application diagram;

[0018] Figure 2 The wiring diagram of the power system source side impedance measuring device provided for the present application;

[0019] Figure 3 A kind of power system source side impedance measuring flow chart provided for the present application;

[0020] Figure 4 Another power system source side impedance measuring flow chart provided for the present application;

[0021] Figure 5 A kind of source equipment impedance indirect measurement principle diagram provided for the present application;

[0022] Figure 6 Three-stage generator simulation model diagram provided for the present application;

[0023] Figure 7 System impedance simulation verification result diagram provided for the present application;

[0024] Figure 8 Load impedance simulation verification result diagram provided for the present application;

[0025] Figure 9 Three-stage generator output impedance simulation verification result diagram provided for the present application. DETAILED DESCRIPTION

[0026] In order to better understand the above technical solutions, the technical solutions of the embodiments of the present application are described in detail below through the drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of the present application, and are not limitations of the technical solutions of the present application. In the case of no conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other.

[0027] Please refer to Figure 1 The measuring device for source side impedance of a power supply system provided by the present embodiment includes a main working circuit 1, a sampling circuit 2, and a disturbance generating device 3.

[0028] Specifically, as shown in the figure Figure 1 The main working circuit 1 in the present embodiment includes a source device and a load device, the source device and the load device are connected, and the impedance of the source device is lower than the impedance of the load device. The main working circuit 1 is a working circuit of the source device to be measured. When an example of the source device is a generator, the main working circuit 1 is a generator driving resistance load.

[0029] The disturbance generating device 3 is arranged between the source device and the load device, and is used for setting harmonic injection parameters and injecting voltage disturbance signals of different frequencies into the main working circuit 1 according to the harmonic injection parameters. The sampling circuit 2 is arranged between the load device and the disturbance generating device 3, and is used for collecting the voltage and current between the load device and the disturbance generating device 3 within a predetermined time of injecting the voltage disturbance signals, and transmitting the collected voltage and current to the disturbance generating device 3.

[0030] In the present embodiment, since the small impedance port response signal of the source device is small, there is a large error in direct measurement. The impedance of the entire system and the impedance of the load can be calculated by measuring the disturbance source port signal and the load port signal, respectively, and the impedance of the source device can be calculated by using the difference between the two.

[0031] In an optional embodiment, the disturbance generating device 3 includes a host computer 31, a frequency response analyzer 32, an excitation small signal generating module 33, a linear amplifier unit 34, and an isolation transformer 35 connected in sequence. The isolation transformer 35 is arranged between the source device and the load device, and the host computer 41 is used for setting harmonic injection parameters and injecting voltage disturbance signals of different frequencies into the main working circuit 1 through the isolation transformer 35 according to the harmonic injection parameters.

[0032] In an optional embodiment, the sampling circuit 2 is connected to the frequency response analyzer 32 to transmit the collected voltage and current between the load device and the disturbance generating device 3 to the frequency response analyzer 32.

[0033] like Figure 2 As shown, in an optional embodiment, the source device is a three-phase motor circuit, and the load device consists of three resistors connected in parallel. Each phase of the three-phase motor circuit is connected in series with a resistor in the load device.

[0034] Based on the operating circuit of the device under test, determine the voltage and current sampling ports. Sampling is achieved through voltage and current probes. Taking an ABC three-phase system as an example, since it is a three-phase circuit, at least two phase voltages and currents need to be sampled. Taking the voltages ab and bc and the phase currents a and b at the sampling terminals of the frequency response analyzer as an example, the measurement wiring is shown below. Figure 2 As shown, the sampling circuit 2 is used to collect the current I of phase a in the three-phase motor circuit. a Current I in term b b ; and to collect the voltage Δu between phases ab in the three-phase motor circuit. ab The voltage Δu between phases b and c bc .

[0035] The host computer 31 is also used to calculate the impedance of the source device based on the collected voltage and current. Specifically, the host computer 31 analyzes the sampled data, obtains the sequence voltage and sequence current components through coordinate transformation, calculates the impedance of the measured system and the load impedance, and then, based on the principle of indirect measurement, subtracts the load impedance from the system impedance to obtain the impedance of the source device.

[0036] The embodiment provides a kind of power system source side impedance measuring device, the measuring device includes: main working circuit, sampling circuit, disturbance generation device, main working circuit includes source equipment and load equipment.Wherein, the source equipment and the load equipment are connected, the impedance of the source equipment is lower than the impedance of the load equipment;The disturbance generation device is arranged between the source equipment and the load equipment, the disturbance generation device is used to set harmonic injection parameter, and different frequency voltage disturbance signal is injected into the main working circuit according to the harmonic injection parameter;The sampling circuit is arranged between the load equipment and the disturbance generation device, for collecting the voltage and current between the load equipment and the disturbance generation device in the predetermined time of injecting the voltage disturbance signal, and the collected voltage and current are transmitted to the disturbance generation device.This embodiment disturbance generation device controls the output of different frequency harmonic injection parameter, then harmonic injection parameter corresponding disturbance signal is injected into main working circuit, and the disturbance response consistent with the frequency of injected disturbance signal is generated in main working circuit, and the voltage and circuit collected in sampling circuit can calculate the power system source side impedance.

[0037] As Figure 3 And Figure 4 The utility model embodiment provides a kind of power system source side impedance measuring method, the method is applied to the disturbance generation device 1 in the measuring circuit of above-mentioned power system source side impedance, and the method includes:

[0038] S101, in response to the operation of power system source side impedance measuring device, different frequency voltage disturbance signal is injected into main working circuit according to harmonic injection parameter.

[0039] Wherein, the main working circuit includes source equipment and load equipment;In an alternative embodiment, before different frequency voltage disturbance signal is injected into main working circuit according to harmonic injection parameter, the method further includes: determining the harmonic injection parameter according to the rated working state of the source equipment, and the harmonic injection parameter includes: harmonic injection frequency range, step and harmonic amplitude.

[0040] S102, in the predetermined time of injecting the voltage disturbance signal, the voltage and current between the load equipment and the disturbance generation device are collected.

[0041] In an alternative embodiment, the source equipment is three-phase motor circuit, and the voltage and current between the source equipment and the fundamental frequency blocking device are collected, including: collecting the current i a , the current i b of a item in the three-phase motor circuit;And the voltage u ab Between ab phase and the voltage ubc .

[0042] S103, calculate the impedance of the source device based on the collected current and voltage.

[0043] In this embodiment, the frequency range, step size, and harmonic amplitude of the harmonic injection are set according to the measurement requirements. These settings are configured in the frequency response analyzer via a disturbance generator, based on the generator power under test, rated frequency, and the desired accuracy of the generator impedance. After configuration, the source device is activated and put into test mode. Harmonic injection at the corresponding frequency is then initiated via the disturbance generator. The voltage and current values ​​at the corresponding sampling port are collected for each set frequency harmonic injection. The impedance of the source device is then calculated based on the collected voltage and current values.

[0044] Specifically, this embodiment indirectly acquires the injected disturbance voltage, system current, and load response voltage at the corresponding frequency to obtain the system impedance and the load impedance, which is easier to measure. Then, the impedance of the source device is calculated by subtracting the load impedance from the system impedance. Thus, the impedance measurement of the source device is realized through this embodiment.

[0045] like Figure 5 The diagram shown is a schematic of the measurement method using a single-port system as an example, as provided in this embodiment. The impedance to be measured is the power port impedance Z. g The sampled data is the current ΔI flowing through the system. a Injected disturbance voltage ΔV p and the response voltage Δu at the load end. l From ΔV p The impedance Z of the entire system can be obtained from / ΔI. s , by Δu l / ΔI a The load impedance Z can be obtained. l Then the source impedance is Z g =Z s -Z l =ΔV p / ΔI a -Δu l / ΔI a .

[0046] like Figure 2 As shown, if the source device is a three-phase motor circuit, firstly, determine the voltage and current sampling ports according to the working circuit of the source device under test. Sampling is achieved through voltage and current probes. Taking an ABC three-phase system as an example, since it is a three-phase circuit, at least two phases of voltage and current need to be sampled. The voltage sampled and measured is the voltage u between phases ab at the generator output terminal. ab The voltage u between phases b and c bc, the sampled measured current is the a-phase current i a , the sampled measured current is the b-phase current i b . Then, the collected voltage and current values are input into the frequency response analyzer CH.1, CH.2, CH.3, and CH.4, and after the harmonic injection in the set frequency range is completed, the source device stops outputting.

[0047] According to the measurement requirements, the frequency range, step, and harmonic amplitude of the harmonic injection are set. After the setting is completed, the source device is allowed to work and output, and after working in the state to be measured, the corresponding frequency disturbance injection is performed through the upper computer instruction. The voltage and current values of the corresponding sampling port at each set frequency harmonic injection are collected, and after the harmonic injection in the set frequency range is completed, the source device stops working and outputting.

[0048] Finally, the sampling data is analyzed by the upper computer, the sequence voltage and sequence current components are obtained through coordinate transformation, the impedance of the measured system and the impedance of the load are calculated, and then according to the indirect measurement principle, the impedance of the source device is obtained by subtracting the impedance of the load from the impedance of the system. The specific calculation process is as follows:

[0049] The system impedance Z S (s) of the three-phase circuit is calculated by the following formula:

[0050]

[0051] The impedance Z l (s) of the load device is calculated by the following formula:

[0052]

[0053] The source device impedance Z g (s) is calculated by the following formula:

[0054]

[0055] Where, Δu p is the voltage of the isolation transformer in the disturbance generating device. Z p (s) is the positive sequence impedance of the source device, Z n (s) is the negative sequence impedance of the source device, and the s in the parentheses of the positive sequence impedance and the negative sequence impedance represents the frequency domain representation of the impedance.

[0056] This embodiment provides a method for measuring the source-side impedance of a power supply system. When a disturbance signal is injected, the response signal at the low-impedance port on the source side is small, leading to significant errors when measured directly. This embodiment calculates the impedance of the entire system and the impedance of the load by measuring the disturbance source port signal and the load port signal, respectively, and then uses the difference between the two to calculate the impedance of the source device. In actual measurement, by indirectly measuring the significantly responsive disturbance response signal at the load end, measurement errors can be effectively avoided, measurement accuracy can be improved, and more precise source impedance measurement can be achieved.

[0057] In this embodiment, a three-stage generator, a common low-impedance source device in aviation power systems, is used as an example. Figure 6 An implementation example of measuring the output impedance of a three-stage generator is shown. For example... Figure 6 As shown, the three-stage generator output impedance measurement in this embodiment includes the main operating circuit of the main three-stage generator driving resistive load and a disturbance signal injection and measurement device. The disturbance signal is injected into one phase of the main circuit, and the system impedance and load impedance are obtained by measuring the response voltage and current at the measuring port, thereby calculating the impedance of the source device under test.

[0058] Optionally, the three-stage generator employs proportional-integral closed-loop control, controlling the generator's output voltage to 230V / 400Hz. The load uses a purely resistive circuit, and in Example 1, the output power is 50kW. The measurement simulation in this embodiment is based on the MATLAB simulation platform. The source device impedance is calculated by injecting a disturbance signal and sampling the voltage and current response signals at the port. The sampling circuit is implemented by a voltage and current measurement module. FFT analysis is performed on the sampled data to obtain the impedance at each frequency, thereby obtaining the impedance model for the desired frequency band.

[0059] Figure 7 , 8 Figure 9 shows the impedance sweep frequency measurement results in the simulation model of this embodiment, including the measurement and calculation results of the system impedance Zs, load impedance Zl, and the calculated impedance Zg of the three-stage generator of the source device. At the same time, the results of the indirect measurement method proposed in this embodiment and the three-stage generator output impedance obtained by directly sampling the output port voltage and current of the three-stage generator were compared. It can be seen that the results of the two measurement methods are basically consistent, which verifies the theoretical effectiveness of the method.

[0060] Depend on Figure 7 , 8 The comparison results of items 9 and 1 show that the power system source-side impedance measurement device and method proposed in this embodiment can effectively measure the relatively small output impedance of the three-stage generator on the power supply side. In actual measurement, since the load-side disturbance response signal with obvious response is measured indirectly, measurement errors can be effectively avoided, measurement accuracy can be improved, and more accurate source impedance measurement can be achieved.

[0061] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiment methods. Any reference to memory, storage, database or other medium used in the embodiments provided by the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synch link) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0062] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of functional units and modules is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the above-described functions.

[0063] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A device for measuring the source-side impedance of a power supply system, characterized in that, The measuring device comprises a main working circuit, a sampling circuit and a disturbance generating device, wherein the main working circuit comprises a source device and a load device; The source device and the load device are connected, and the impedance of the source device is lower than that of the load device; The disturbance generating device is arranged between the source device and the load device, and is used for setting a harmonic injection parameter and injecting voltage disturbance signals of different frequencies into the main working circuit according to the harmonic injection parameter; The sampling circuit is arranged between the load device and the disturbance generating device, and is used for collecting voltage and current between the load device and the disturbance generating device within a predetermined time of injecting the voltage disturbance signals, and transmitting the collected voltage and current to the disturbance generating device.

2. The measuring device of claim 1, wherein, The disturbance generating device comprises a host computer, a frequency response analyzer, an excitation small signal generating module, a linear amplifier unit and an isolation transformer which are connected in sequence. The isolation transformer is arranged between the source device and the load device, and the host computer is used for setting a harmonic injection parameter and injecting voltage disturbance signals of different frequencies into the main working circuit through the isolation transformer according to the harmonic injection parameter.

3. The measuring device of claim 2, wherein, The sampling circuit is connected with the frequency response analyzer, and is used for transmitting the collected voltage and current between the load device and the disturbance generating device to the frequency response analyzer.

4. The measuring device of claim 3, wherein, The source device is a three-phase motor circuit, and the load device is composed of three parallel resistors.

5. The measuring device of claim 4, wherein, Each of the three-phase motor circuits is connected in series with a resistor in the load device.

6. The measuring device of claim 5, wherein, The sampling circuit is used to collect the a-phase current I a , the b-phase current I b , and the voltage Δu ab between the a-phase and the b-phase and the voltage Δu bc between the b-phase and the c-phase in the three-phase motor circuit.

7. The measuring device of claim 2, wherein, The host computer is further used for calculating the impedance of the source device according to the collected voltage and current.

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