CN112737288A

CN112737288A - Multifunctional power electronic load device

Info

Publication number: CN112737288A
Application number: CN202110090515.5A
Authority: CN
Inventors: 凌万水; 王科龙
Original assignee: Jiangsu Jinzhi Technology Co ltd
Current assignee: Jiangsu Jinzhi Technology Co ltd
Priority date: 2021-01-22
Filing date: 2021-01-22
Publication date: 2021-04-30

Abstract

The invention discloses a multifunctional power electronic load device, which comprises a load module, a capacitor module and an energy feedback module, wherein the load module, the capacitor module and the energy feedback module are connected in parallel to a first connecting port and a second connecting port, and the load module is connected with a three-phase power supply; the capacitor module comprises a first capacitor and a second capacitor, the first capacitor and the second capacitor are connected in series, the first switch is connected with the second connection port, the second switch is connected between the first capacitor and the second capacitor, and the intersection of the first switch and the second switch is connected to a neutral point; according to the invention, the circuit topology structure is changed by controlling the switch tube of the load module, the switch S1 on the neutral line and the switch S2 on the outgoing line of the lower bridge arm, so that the device is suitable for performance tests of a three-phase power supply, a single-phase power supply and a direct-current power supply; the function and the application range of the power electronic load device are widened, and the economical practicability of the power electronic load is improved.

Description

Multifunctional power electronic load device

Technical Field

The invention relates to the technical field of application of power electronics in a power system, in particular to a multifunctional power electronic load device.

Background

With the continuous progress of science and technology and the rapid development of economy, electric energy becomes more and more important as an important energy form. The performance of the power supply, which is used as a device for supplying electric energy, determines whether the power supply can be applied to electric equipment and can meet the power supply standard required by the electric equipment. Once the power supply in the working state breaks down, serious safety accidents and economic losses are possibly caused, danger is brought to personnel, and unnecessary losses are brought to the country. Therefore, it is necessary to test the performance of the power supply to evaluate the safety and reliability of the power supply. The test load used by the conventional test power supply has a large volume, and electric energy is consumed in the test process, so that electric energy waste is caused. The power electronic load as a power electronic device can realize the simulation of linear load and nonlinear load and the energy feedback of a power supply to a power grid, and realizes the efficient utilization of energy. At present, a common power electronic load is usually based on a back-to-back structure, a load analog converter and an energy feedback converter are formed by two three-phase full-bridge inverters, a capacitor is connected in parallel in the middle, the load analog converter is used for simulating the characteristics of various loads, and the energy feedback converter can convert the electric energy of a power source to be detected into three-phase alternating current with a unit power factor and feed the three-phase alternating current back to a power grid. At present, the power electronic load is designed for a load simulation converter and an energy feedback converter only aiming at one of a three-phase power supply, a single-phase power supply and a direct-current power supply, the application range is small, and the type of a test power supply is single.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

The present invention has been made in view of the problems occurring in the prior art.

Therefore, the technical problem to be solved by the invention is that the current power electronic load is designed for only one of a three-phase power supply, a single-phase power supply and a direct-current power supply, so that the load simulation converter and the energy feedback converter are small in application range and single in test power supply type.

In order to solve the technical problems, the invention provides the following technical scheme: a multifunctional power electronic load device comprises a test unit, a power electronic load unit and a power electronic load unit, wherein the test unit comprises a load module, a capacitance module and a feed-back module, and the load module, the capacitance module and the feed-back module are connected in parallel to a first connection port and a second connection port; and the control unit comprises a first switch and a second switch, the first switch is connected with the second connecting port, the second switch is connected to the central point of the capacitance module, and the first switch and the second switch are connected to a neutral point in a crossing mode.

As a preferable aspect of the multifunctional power electronic load device of the present invention, wherein: the load module comprises a first bridge arm, a second bridge arm and a third bridge arm, wherein the first bridge arm, the second bridge arm and the third bridge arm are connected in parallel.

As a preferable aspect of the multifunctional power electronic load device of the present invention, wherein: the first bridge arm, the second bridge arm and the third bridge arm are all formed by connecting two IGBT tubes in series.

As a preferable aspect of the multifunctional power electronic load device of the present invention, wherein: the IGBT tube is formed by a triode antiparallel diode.

As a preferable aspect of the multifunctional power electronic load device of the present invention, wherein: and a first inductor is connected between two IGBT tubes in the first bridge arm and is connected with an A phase in a three-phase power supply.

As a preferable aspect of the multifunctional power electronic load device of the present invention, wherein: and a second inductor is connected between two IGBT tubes in the second bridge arm and is connected with a phase B in the three-phase power supply.

As a preferable aspect of the multifunctional power electronic load device of the present invention, wherein: and a third inductor is connected between two IGBT tubes in the third bridge arm and is connected with the C phase in the three-phase power supply.

As a preferable aspect of the multifunctional power electronic load device of the present invention, wherein: the energy feedback module is consistent with the load module in structure.

As a preferable aspect of the multifunctional power electronic load device of the present invention, wherein: and two IGBT tubes on each group of bridge arms in the energy feedback module are respectively connected to a power grid through inductors.

The invention has the beneficial effects that: the invention combines the topological structures of the power electronic load under various applicable conditions to form a medium-multifunctional power electronic load device, and the circuit topological structure is changed by controlling the switch tube of the load module, the switch S1 on the neutral line and the switch S2 on the outgoing line of the lower bridge arm so as to be suitable for the performance test of a three-phase power supply, a single-phase power supply and a direct-current power supply; the function and the application range of the power electronic load device are widened, and the economical practicability of the power electronic load is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:

fig. 1 is a schematic diagram of a multifunctional power electronic load in the first, second and third embodiments.

Fig. 2 is a structure diagram of a three-phase IGBT tube in the first, second, and third embodiments.

FIG. 3 is a schematic diagram of a three-phase power stage test power supply according to a first embodiment.

FIG. 4 is a diagram of a single-phase power-level test power supply according to a second embodiment.

FIG. 5 is a diagram of a DC power stage test power supply according to a third embodiment.

Fig. 6 is a graph of intermediate capacitor voltage waveforms in a third embodiment.

Fig. 7 is a waveform diagram of the net side voltage current in the third embodiment.

Fig. 8 is a diagram of harmonic analysis in the third embodiment.

Fig. 9 is a graph of intermediate capacitor voltage waveforms in the first embodiment.

Fig. 10 is a diagram of the voltage and current waveforms on the network side in the first embodiment.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Example 1

Referring to fig. 1 to 3, 9 and 10, a first embodiment of the present invention provides a multifunctional power electronic load device, which includes a testing unit 500, where the testing unit 500 includes a load module 200, a capacitor module 300 and an energy feedback module 400, where the load module 200 and the energy feedback module 400 are three-phase full-bridge inverters.

Specifically, the load module 200, the capacitor module 300, and the energy feedback module 400 are connected in parallel to the first connection port T and the first connection port K, the load module 200 and the energy feedback module 400 have the same structure and are both composed of 6 IGBT tubes 204, a transistor V in the load module 200 is labeled with V1 to V6, a diode D is labeled with D1 to D6, a transistor V in the energy feedback module 400 is labeled with V7 to V12, and a diode D is labeled with D7 to D12.

Further, the load module 200 includes a first bridge arm 201, a second bridge arm 202, and a third bridge arm 203, where the first bridge arm 201, the second bridge arm 202, and the third bridge arm 203 are connected in parallel, each group of bridge arms is formed by two series-connected IGBT tubes 204, and the IGBT tubes 204 are formed by a triode V anti-parallel diode D.

Further, V1, V3, and V5 constitute an upper arm in load module 200, and corresponding V4, V6, and V2 constitute a lower arm in load module 200, where V1 and V4 are connected in series to form first arm 201, V3 and V6 are connected in series to form second arm 202, and V5 and V2 are connected in series to form third arm 203; two IGBT tubes 204 in the first leg 201 are connected to a first inductor L1, namely a connecting lead between V1 and V4 is connected to a first inductor L1; the two IGBT tubes 204 in the second leg 202 are connected to the second inductor L2, that is, a connecting wire between V3 and V6 is connected to the second inductor L2; the two IGBT tubes 204 in the third arm 203 are connected to the third inductor L3, that is, the connecting wire between V5 and V2 is connected to the third inductor L3; an inductor L1 switches on the A phase of the three-phase power supply, a second inductor L2 switches on the B phase of the three-phase power supply, and a third inductor L3 switches on the C phase of the three-phase power supply.

The control unit 100 is further included and comprises a first switch 101 and a second switch 102, specifically, the capacitor module 300 comprises a first capacitor C1 and a second capacitor C2, a center point of the capacitor module 300 is located between a first capacitor C1 and a second capacitor C2, the first capacitor C1 and the second capacitor C2 are connected in series, the first capacitor C1 is connected to an upper leg of the load module 200, i.e., to collectors of the capacitors V1, V3 and V5, the second capacitor C2 is connected to a lower leg of the load module 200, i.e., to emitters of the capacitors V4, V6 and V2, the first switch 101 is connected to a first connection port K at the lower leg, the second switch 102 is connected between the first capacitor C1 and the second capacitor C2, and the first switch 101 and the second switch 102 are connected to a neutral point N.

The energy feedback module 400 and the load module 200 have the same structure, and two IGBT tubes 204 on each set of bridge arms in the energy feedback module 400 are connected to the power grid through inductors M.

When the first switch 101 and the second switch 102 are both open, the circuit is in a three-phase power supply stage for measuring a three-phase alternating current power supply, and when the second switch 102 is closed and the first switch 101 is open, the circuit is in a single-phase power supply stage for measuring a single-phase alternating current power supply, and when the second switch 102 is open and the first switch 101 is closed, the circuit is in a direct current power supply stage for measuring a direct current power supply.

Further, when the load module 200 is located in a three-phase power supply gear, the topological structure is equivalent to a three-phase full-bridge rectifying circuit to realize an AC-DC function, and a midpoint outgoing line of each bridge arm is connected in series with the first inductor L1, the second inductor L2 and the third inductor L3 to form A, B, C three test points. When the three-phase power supply is used, the three-phase power supply is respectively connected to A, B, C test points, and the V1-V6 is controlled to be switched on and off to control the magnitude of the load analog current, wherein the specific parameters are as follows:

name (R)	Numerical value
		AC voltage peak value (V)	311
Fundamental frequency (Hz)	50
		AC side inductor (mH)	8
DC reference voltage (V)	700
		AC switching frequency (Hz)	5000
Testing AC power supply (V)	311
		Middle capacitor (uF)	4000

The intermediate capacitor voltage waveform is shown in fig. 9, and the grid-side voltage current waveform is shown in fig. 10.

Example 2

Referring to fig. 1, 2 and 4, a second embodiment of the present invention provides a multifunctional power electronic load device, which includes a testing unit 500, where the testing unit 500 includes a load module 200, a capacitor module 300 and an energy feedback module 400, where the load module 200 and the energy feedback module 400 are three-phase full-bridge inverters.

Further, when the single-phase power supply is in a single-phase power supply gear, the measurement point a is connected with the first bridge arm 201 in the load module 200 through the first inductor L1, meanwhile, the first bridge arm 201 is connected with the capacitor module 300 in parallel, a capacitor voltage neutral point outgoing line between the first capacitor C1 and the second capacitor C2 in the capacitor module 300 is connected to the neutral line measurement point N, and the structures form a single-phase half-bridge rectification circuit. When the single-phase power supply is connected between the A test point and the neutral line test point in use, the V1 and the V4 are controlled to be alternately conducted to control the current magnitude.

Example 3

Referring to fig. 1, 2, and 5 to 8, a third embodiment of the present invention provides a multifunctional power electronic load device, which includes a testing unit 500, where the testing unit 500 includes a load module 200, a capacitor module 300, and an energy feedback module 400, where the load module 200 and the energy feedback module 400 are three-phase full-bridge inverters.

And further comprises a first switch 101 and a second switch 102, specifically, the capacitor module 300 comprises a first capacitor C1 and a second capacitor C2, a center point of the capacitor module 300 is located between the first capacitor C1 and the second capacitor C2, the first capacitor C1 and the second capacitor C2 are connected in series, the first capacitor C1 is connected to an upper arm of the load module 200, i.e., connected to collectors of the V1, V3 and V5, the second capacitor C2 is connected to a lower arm of the load module 200, i.e., connected to emitters of the V4, V6 and V2, the first switch 101 is connected to a first connection port K at the lower arm, the second switch 102 is connected between the first capacitor C1 and the second capacitor C2, and the first switch 101 and the second switch 102 are connected to a neutral point N at an intersection.

Further, when the direct current power supply is in a direct current power supply gear, the measuring point a is connected with the first bridge arm 201 in the load module 200 through the first inductor L1, and meanwhile, the first bridge arm 201 is connected with the capacitor module 300 in parallel, the first capacitor C1, the second capacitor C2 and the collector outgoing line of the V4 are connected with the neutral line measuring point N to form a current reversible chopper circuit. When the direct-current power supply is connected between the A test point and the neutral line test point in use, the control of the connection or disconnection of the V1 and the V4 can form a buck chopper circuit and a boost chopper circuit. When the voltage V1 is switched on and the voltage V4 is switched off, the load module 200 is a voltage reduction type DC-DC circuit, the voltage V4 and the voltage D2 are always in an off state, after the voltage V1 is switched off, because the energy in the first inductor L1 is small, the current is zero after the energy in the first inductor L1 is released, the magnitude of the load analog current can be controlled by controlling the duty ratio of the voltage V1, the voltage reduction chopping function is realized, and the voltage reduction chopping circuit is suitable for occasions when the voltage of the detected power supply is higher than the voltage of the capacitor. When V1 is turned off and V4 is turned on, the load module 200 is a boost DC-DC circuit, V1 and D1 are always in an off state, after V4 is turned on, energy is accumulated in an inductor L1, and when V4 is turned off, the energy in the inductor L1 and the energy of the power supply to be tested release electric energy to a first capacitor C1 and a second capacitor C2 at the same time, the magnitude of the load analog current can be controlled by controlling the duty ratio of V4, so that the boost chopper function is realized, and the boost DC-DC circuit is suitable for the occasion that the voltage of the power supply to be tested is lower than the voltage of the capacitors at this time, and specific test parameters:

name (R)	Numerical value
		AC voltage peak value (V)	380
Fundamental frequency (Hz)	50
		AC side inductor (mH)	2
DC reference voltage (V)	800
		AC switching frequency (Hz)	1000
DC power supply (V)	200
		Middle capacitor (uF)	3000

The voltage waveform diagram of the middle capacitor is shown in fig. 6, the voltage waveform diagram of the network side is shown in fig. 7, the harmonic analysis is shown in fig. 8, and simulation results show that the multifunctional power electronic load can test a direct-current power supply and an alternating-current power supply, the middle capacitor voltage can be rapidly stabilized at a set value compared with the prior art through waveform analysis, the middle capacitor voltage is not overshot during the test of the three-phase power supply, the system is rapidly stabilized, and the reaction speed is high. The energy feedback side realizes unit factor grid connection, the total harmonic distortion rate of the direct-current power supply grid connection is 3.19% through harmonic analysis, harmonic damage is avoided, and grid connection conditions are met.

It is important to note that the construction and arrangement of the present application as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in this application. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of this invention. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present inventions. Therefore, the present invention is not limited to a particular embodiment, but extends to various modifications that nevertheless fall within the scope of the appended claims.

Moreover, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not be described (i.e., those unrelated to the presently contemplated best mode of carrying out the invention, or those unrelated to enabling the invention).

It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.

Claims

1. A multifunctional power electronic load device is characterized in that: comprises the steps of (a) preparing a mixture of a plurality of raw materials,

a test unit (500) comprising a load module (200), a capacitance module (300) and an energy feedback module (400), the load module (200), the capacitance module (300) and the energy feedback module (400) being connected in parallel to the first connection port (T) and the second connection port (K); and the number of the first and second groups,

a control unit (100) comprising a first switch (101) and a second switch (102), the first switch (101) being connected to the second connection port (K), the second switch (102) being connected to a center point of the capacitive module (300), the first switch (101) and the second switch (102) meeting to a neutral point.

2. A multifunctional power electronic load device according to claim 1, characterized in that: the load module (200) comprises a first bridge leg (201), a second bridge leg (202) and a third bridge leg (203), wherein the first bridge leg (201), the second bridge leg (202) and the third bridge leg (203) are connected in parallel.

3. A multifunctional power electronic load device according to claim 2, characterized in that: the first bridge arm (201), the second bridge arm (202) and the third bridge arm (203) are all formed by connecting two IGBT tubes (204) in series.

4. A multifunctional power electronic load device according to claim 3, characterized in that: the IGBT tube (204) is formed by a triode (V) antiparallel diode (D).

5. A multifunctional power electronic load device according to claim 3, characterized in that: two IGBT tubes (204) in the first bridge arm (201) are connected to a first inductor (L1), and the first inductor (L1) switches on an A phase in a three-phase power supply.

6. A multifunctional power electronic load device according to claim 3 or 5, characterized in that: two IGBT tubes (204) in the second bridge arm (202) are connected to a second inductor (L2), and the second inductor (L2) switches on the B phase in a three-phase power supply.

7. The multifunctional power electronic load device according to claim 6, wherein: two IGBT tubes (204) in the third bridge arm (203) are connected to a third inductor (L3), and the third inductor (L3) switches on the C phase in a three-phase power supply.

8. A multifunctional power electronic load device according to claim 1, characterized in that: the energy feedback module (400) is consistent with the load module (200) in structure.

9. A multifunctional power electronic load device according to claim 8, characterized in that: two IGBT tubes (204) on each group of bridge arms in the energy feedback module (400) are connected to a power grid through inductors (M).