CN211508621U

CN211508621U - Physical network impedance device

Info

Publication number: CN211508621U
Application number: CN201922230549.0U
Authority: CN
Inventors: 郭芷瑄
Original assignee: Ppst Shanghai Co ltd
Current assignee: Ppst Shanghai Co ltd
Priority date: 2019-12-11
Filing date: 2019-12-11
Publication date: 2020-09-15
Anticipated expiration: 2029-12-11

Abstract

The utility model provides a pair of entity network impedance device, include: a power supply member; a voltage current control circuit for performing voltage and current; an inductor connected with the voltage and current control circuit; a first resistor having one end connected to the inductor; the second resistor is connected with the other end of the first resistor at one end and is connected with a terminal of the circuit; the first relay is connected with the first resistor, the second resistor and the inductor in parallel; a second relay connected in parallel with the second resistor; and a relay drive control circuit for driving the first relay and the second relay such that the physical network impedance device is operable in one of a bypass mode and a blink mode; the utility model adopts the unsaturated hollow coil to solve the volume and weight problem of the coil with the iron core; the problem of temperature compensation calibration is solved by connecting the metal resistor and the adjustable resistor in parallel. Meanwhile, the built-in high-speed data acquisition card DAQ and the phase-locked loop PLL technology are utilized to improve the repeatability and consistency of test data.

Description

Physical network impedance device

Technical Field

The utility model relates to an electric field, more specifically relates to an entity network impedance device.

Background

In the latest electromagnetic compatibility test standards, the requirements of harmonic current and voltage flicker of equipment or products accessed to a public power grid exist, and the standards divide current harmonic limit values into a harmonic current emission limit value of equipment with input current not exceeding 16A per phase and a harmonic current limit value generated by equipment with input current more than 16A per phase and less than or equal to 75A public low-voltage system connection according to the difference of the current of each phase; the voltage flicker limit is divided into "a limit value of voltage fluctuation in a low voltage power supply system in which the rated current does not exceed the 16A device" and "a limit value of voltage variation, voltage fluctuation, and flicker rated current 75A in a low voltage power supply system and a device which needs conditional connection".

The above-mentioned limit requirements correspond to the latest international electrotechnical commission IEC standard, respectively:

IEC61000-3-2 standard 2018, the input current of each phase does not exceed the harmonic current emission limit of 16A equipment;

according to IEC61000-3-12 standard 2011, the input current of each phase is more than 16A and less than or equal to 75A, and the limit value of harmonic current generated by equipment connected with a public low-voltage system is used;

IEC61000-3-3 standard 2017, rated current does not exceed the voltage fluctuation limit value in the low-voltage power supply system of 16A equipment; and

IEC61000-3-11 standard 2017, limit current rating of 75A for voltage variation, voltage fluctuation and flicker in low voltage supply systems and requires conditionally connected devices.

Aiming at the limit requirements, the corresponding latest Chinese national standard administration committee GB standard is also provided:

GB17625.1 standard 2012, with each phase input current not exceeding the harmonic current emission limit of 16A devices;

GB17625.8 standard 2015, input current of each phase is more than 16A and less than or equal to 75A, and the input current is limited by harmonic current generated by equipment connected with a low-voltage system;

GB17625.2 standard 2007, rated current does not exceed the voltage fluctuation limit in low voltage power supply systems for 16A devices;

GB17625.7 standard 2013, a device which is connected with a voltage change, voltage fluctuation and flickering in a low-voltage power supply system in a condition of a limit rated current 75A;

according to the latest IEC and GB standards related to harmonic current and voltage flicker, the tested equipment needs to be subjected to type tests by referring to the circuit shown in FIG. 1 according to the specific requirements in IEC61000-3-11 standard and GB17625.7 for voltage change, voltage waveform and flicker limit parts in a low-voltage power supply system.

In fig. 1, R represents resistance, and X represents inductance. And Z ═ R + jX, referred to as reference impedance Zref.

For network impedances, including reference impedance and test impedance, the GB17625.7 standard requires that the circuit described in fig. 2 be used,

In fig. 2, R represents resistance and X represents inductance. And Z ═ R + jX, referred to as reference impedance Zref.

Different values of resistance R, different values of Z are obtained, which are respectively called reference impedance Zref and test impedance Ztest.

The physical network impedance is a hardware impedance having both the reference impedance Zref and the test impedance Ztest.

At present, the following schemes are mostly adopted to meet the requirements of IEC61000-3-11 and GB17625.7 on entity network impedance:

scheme 1 adopts the heavy iron core that contains the silicon steel sheet material of bulky weight, twines the copper cable that certain surface attached with the insulated paint according to certain winding method, makes the inductance L of specific specification, then connects in series a resistance R. For a single-phase low-voltage power supply system, the system comprises 1R and 1L. The N lines also contain 1R and 1L. The total physical network impedance is 2R and 2L. The inductor L and the resistor R, which comprise an iron core made of silicon steel sheet, receive a current of 75Arms, a power Pr of 1350W, a power Ql of 843.75W, and an apparent power S of 1591.98 VA. The whole entity network impedance is placed in a large cabinet, air enters the front or the rear of the bottom of the cabinet, and an electric fan is arranged at the top of the cabinet to draft air, so that heat dissipation is enhanced. The weight of the cabinet is more than 100Kg, and the volume of the cabinet is 600mm wide, 800mm deep and 1700mm high.

According to the scheme 2, parameters of a voltage and current phase angle are obtained by measuring a voltage and current circuit, various data obtained by a data acquisition card DAQ are analyzed by utilizing upper computer software, a network impedance is virtualized by software according to a Fast Fourier Transform (FFT) algorithm after the data are processed by a digital filter PID and the like, and then a virtualized voltage flicker value is calculated. Vex is Vg-I (Z + Vg/I). Where Z is R + jX, Vg is the output voltage of the source, I is the loop current, and Veut is the voltage of the dut.

However, according to the above scheme 1, it can be known that the inductor uses a coil with an iron core, and the resistor uses a fixed resistance value, resulting in a large volume and heavy weight of the whole device, and the weight of the whole device can reach more than 100Kg, the volume width is at least 600mm, the depth is at least 800mm, and the height is at least 1700mm in terms of single-phase 75Arms physical network impedance. In addition, the body heat dissipation problem of the inductor L and the resistor R of the component is considered, air must be fed into the bottom of the component, and air must be exhausted from the top of the component. In addition, the inductor L and the resistor R have temperature rise problems, so that the resistance value of the inductor L and the resistor R is changed, the temperature rises, the resistance values of the inductor L and the resistor R are increased, the Z value of the whole device is changed accordingly, the measured value of the object to be measured Veut is low, and the voltage flicker value is calculated inaccurately. Although temperature compensation or calibration can be performed in software, there are many factors that are not reliable. In addition, the scheme employs a set of impedance modes, and two sets of impedance modes are required for the physical network impedance according to the requirements of the latest international electrotechnical commission IEC61000-3-11 and the latest chinese national standard regulatory commission GB 17625.7. Therefore, the scheme 1 has the problems of difficult calibration of the inductor L and the resistor R, temperature compensation, large volume, heavy weight, a group of impedance modes and the like.

From the above scheme 2, we can also see that the data acquisition card DAQ is used to perform analog-to-digital conversion of the voltage and current parameters, then through calculation of the fast fourier FFT algorithm, software virtualizes an impedance, and calculates the flicker value of the voltage according to the above formula, and there is a numerical error of the digital-to-analog conversion in this process, and then there is an error of the software algorithm. Therefore, the scheme 2 has the problems of poor repeatability and poor data consistency of the test data.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem, the utility model provides an entity network impedance device, it can improve test data repeatability and uniformity.

In order to realize the above object of the present invention, the utility model provides an entity network impedance device includes:

a power supply member;

a voltage current control circuit for performing voltage and current;

the inductor is connected with the voltage and current control circuit;

a first resistor having one end connected to the inductor;

the second resistor is connected with the other end of the first resistor at one end and is connected with a terminal of a circuit;

a first relay connected in parallel with the first resistor, the second resistor and the inductor;

the second relay is connected with the second resistor in parallel; and

a relay drive control circuit for driving the first relay and the second relay such that the physical network impedance device is operable in one of a bypass mode and a blink mode.

Further, the power supply part provides 12V direct-current voltage output for supplying power.

The utility model provides an entity network impedance device solves calibration, compensation, volume, weight, impedance mode singleness, data repeatability, the data uniformity problem that above-mentioned two schemes exist emphatically, adopts entity network impedance keeping scheme 1, abandons under the virtual network impedance's that scheme 2 adopted the prerequisite, invents a new installation that adopts the parallelly connected and switching of unsaturated hollow coil multichannel resistance cluster, is exactly a new entity network impedance. The device adopts unsaturated hollow coils, so that the problem of volume and weight of coils containing iron cores is solved; a plurality of metal resistors are connected in series and in parallel and switched, so that the problems of temperature compensation calibration and a group of impedance modes are solved. Meanwhile, the built-in high-speed data acquisition card DAQ and the phase-locked loop PLL technology are utilized to improve the repeatability and consistency of test data.

Drawings

Figure 1 is a network impedance circuit as required by the existing IEC61000-3-11 standard.

Fig. 2 is a network impedance circuit required by the existing GB17625.7 standard.

Fig. 3 is a schematic diagram of an embodiment of a physical network impedance device of the present invention.

Detailed Description

The following describes the present invention in detail with reference to the accompanying drawings.

As shown in fig. 3, the physical network impedance device of the present invention includes a power supply unit SMPS1, a voltage/current control circuit Brd1 for performing voltage and current, a first relay RL1A, RL7A, a second relay RL2A, RL8A, a relay drive control circuit Brd2, a first resistor R1, R7, a second resistor R2, R8, a relay drive control circuit Brd2, a relay drive control circuit Brd2 for driving the relay, and inductors L1 and L4.

The power supply section SMPS1 employs an AC/DC conversion module to convert 220Vac, 50Hz AC power to +12Vdc, 2.1A DC power, the integrated block being of the type Hengfu HF 25W-SL-12.

The relay driving circuit Brd2 mainly amplifies the driving voltage of low current to drive the relays RL1B, RL2B, RL7B and RL8B, and plays a role in isolation to prevent the actuation and release of the relays, which causes the instability of power supply voltage.

In this embodiment the power supply circuit is single phase, provided with two electrode lines 1 and 2. In the circuit 1, the first resistor is R1, the second resistor is R2, the inductor is L1, and the corresponding first relay is composed of RL1A and the second relay is RL 2A; in the line 2, the first resistor is R7, the second resistor is R8, the inductor is L4, and the corresponding first relay is composed of RL7A and a second relay RL 8A.

In the line 1, one end of the inductor L1 is connected to the port 1 of the voltage-current control circuit Brd1, and the other end is connected to one end of the first resistor R1. One end of the second resistor R2 is connected to the other end of the first resistor R1, and the other end thereof is connected to the terminal TB1 (L1). The second relay RL2A is connected in parallel with the second resistor R2, and the first relay RL1A is connected in parallel with the first resistor R1, the second resistor R2, and the inductor L1.

Similarly, in the line 2, one end of the inductor L4 is connected to the port 4 of the voltage-current control circuit Brd1, and the other end is connected to one end of the first resistor R7. One end of the second resistor R8 is connected to the other end of the first resistor R7, and the other end thereof is connected to the terminal TB4 (N). The second relay RL8A is connected in parallel with the second resistor R8, and the first relay RL7A is connected in parallel with the first resistor R7, the second resistor R8, and the inductor L4.

The power supply section SMPS1 provides a 12V dc voltage output to power the entire device.

The relay drive control circuit Brd2 is connected to the relays RL1B, RL7B, RL2B and RL8B to drive the relays RL1A, RL7A, RL2A and RL8A of the associated lines 1 and 2, so that the physical network impedance device of the present invention can operate in one of a bypass mode and a flicker mode (see lines 3 and 4 in fig. 3 and the Leds integrated block).

The bypass mode is that the system does not need a solid resistor R and a solid inductor L to be connected in series into the whole test loop when harmonic current measurement of IEC or GB standard is carried out, so that the resistors R1 and R2, R7 and R8 and inductors L1 and L4 are needed to be short-circuited, and the work is mainly performed by relays RL1A and RL7A (see FIG. 3).

The flicker mode is also called as a flicker test mode, and means that when the system performs voltage flicker measurement of IEC or GB standard, a solid resistor R and a solid inductor L are required to be connected in series in the whole test loop, so that R and L cannot be short-circuited, and the work is mainly performed by relays RL1A, RL7A, RL2A and RL 8A.

In the embodiment of the present invention, there are also electric FANs FAN1 and FAN2, which are used to cool the circuit and ensure the stable and normal operation of the circuit.

The Brd1 and the Brd2 jointly form a measurement control circuit, wherein the Brd1 measures voltage and current and communicates with a USB; brd2 drives relays RL1, 7, 2, 8 so that the physical network impedance can operate in bypass mode or blink mode.

L1, 4 is the inductance L of A, N of the physical network impedance, and R1 and R2, R7 and R8 are the resistance R of the physical network impedance, respectively. The resistance value of R is controlled by switching RL2 and RL8 relays.

The whole entity network impedance automatically controls a bypass or a flicker mode through USB1 and 2 interfaces by computer software, and controls the value of the resistor R, thereby realizing the switching of the reference impedance Zref and the test impedance Ztest.

The impedance of the whole entity network can realize the automatic switching of the impedance, the automatic switching of the mode, the automatic measurement of the electrical parameters such as voltage, current and the like.

Referring to fig. 3, the operation process of the physical network impedance device of the present invention is as follows:

the input ends TB1, 4 are connected with the output end of the programmable AC power supply, the output ends SOCKET1, 2 are connected with an EUT (object to be tested), and the USB1, 2 interfaces of the device are connected with an upper computer. The upper computer runs harmonic flicker test software HFA, after the software is simply set, the output voltage and the frequency of the programmable control alternating current power supply are fully automatically controlled, harmonic test is carried out by switching a bypass mode, and flicker test is carried out by a flicker mode. The whole testing process does not need manual intervention, the testing data is automatically stored in a computer through the USB1 and 2 communication interfaces and is displayed in real time, the mode is automatically selected, the report is automatically generated, the testing result is automatically judged, and the manual entry error is avoided.

As can be seen from the above description, the utility model provides an entity network impedance device solves calibration, compensation, volume, weight, impedance mode singleness, data repeatability, the data uniformity problem that above-mentioned two schemes exist emphatically, adopts entity network impedance in keeping scheme 1, under the virtual network impedance's that scheme 2 adopted was abandoned, invents a new device that adopts the parallel connection of unsaturated hollow coil multichannel resistance cluster and switch, is exactly a new entity network impedance. The device adopts unsaturated hollow coils, so that the problem of volume and weight of coils containing iron cores is solved; a plurality of metal resistors are connected in series and in parallel and switched, so that the problems of temperature compensation calibration and a group of impedance modes are solved. Meanwhile, the built-in high-speed data acquisition card DAQ and the phase-locked loop PLL technology are utilized to improve the repeatability and consistency of test data.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art will understand that modifications and equivalent substitutions can be made to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention, and all of them shall fall within the scope of the claims of the present invention.

Claims

1. A physical network impedance device, comprising:

a power supply member;

a voltage current control circuit for performing voltage and current;

the inductor is connected with the voltage and current control circuit;

a first resistor having one end connected to the inductor;

the second relay is connected with the second resistor in parallel; and

a relay drive control circuit for driving said first relay and said second relay such that said physical network impedance device is operable in one of a bypass mode and a blink mode;

2. A physical network impedance apparatus according to claim 1, wherein the power supply means provides a dc voltage output of 12V to supply power.