Voltage quality control device and method

Abstract

The invention relates to a voltage quality control device and method. The device comprises a plurality of connection switch groups, each connection switch group at least comprises a first gating switch and a second gating switch, the first gating switch is used for being connected with a first phase feeder line, and the second gating switch is used for being connected with a second phase feeder line; the change-over switch group at least comprises a first change-over switch and a second change-over switch, and a plurality of first ends of the first change-over switch are respectively connected with the first gating switches in the connection switch groups; a plurality of first ends of the second change-over switch are respectively connected with the second gating switches in the connection switch groups; and the voltage control module is connected with the second end of each change-over switch in the change-over switch group and each gating switch in the connection switch group, and is used for providing compensation voltage. The voltage quality control device can improve the utilization rate of the voltage control module and reduce the cost.

Description

Technical Field

[0001] The present invention relates to the field of electronic power technology, and in particular to a voltage quality control device and method. Background Art

[0002] With the rapid development of electronic power technology, the proportion of sensitive loads in the distribution network is increasing. With the development of science and technology, high-tech manufacturing industries such as intelligent equipment and robots, electronic communication devices, and advanced manufacturing industries such as automobiles and petrochemicals are more sensitive to power quality disturbances and have strict requirements on the quality of power supply. At the same time, power users are using more and more digital control automation equipment to improve production efficiency, which makes variable frequency speed regulation drives, programmable logic controllers and other equipment widely used in industrial production. The normal operation of these equipment also depends on stable voltage. Therefore, the requirements of power users for power quality are also increasing day by day.

[0003] In the traditional way, a large number of DVRs (Dynamic Voltage Restorers) are usually configured in the distribution network to help stabilize the power quality. For example, a DVR is configured for each feeder, so that when the voltage drops on the feeder, the corresponding DVR can perform voltage compensation. This method will bring high configuration costs. Summary of the invention

[0004] Based on this, it is necessary to provide a voltage quality controller that can solve the above technical problems to achieve feeder voltage compensation.

[0005] In a first aspect, the present application provides a voltage quality control device, comprising:

[0006] A plurality of connection switch groups, each of the connection switch groups at least comprising a first gate switch and a second gate switch, wherein the first gate switch is used to connect to a first phase feeder, and the second gate switch is used to connect to a second phase feeder;

[0007] a switching switch group, comprising at least a first switching switch and a second switching switch, wherein a plurality of first ends of the first switching switch are respectively connected to the first selection switches in each of the connection switch groups; a plurality of first ends of the second switching switch are respectively connected to the second selection switches in each of the connection switch groups;

[0008] The voltage control module is connected to the second end of each switch in the switch group and each selection switch in the connection switch group, and is used to provide a compensation voltage.

[0009] In one embodiment, each of the connecting switch groups further includes a third gating switch, and the third gating switch is used to connect to a third phase feeder; the switching switch group further includes a third switching switch, and multiple first ends of the third switching switch are respectively connected to the third gating switch in each of the connecting switch groups.

[0010] In one embodiment, the input end of the voltage control module is connected to the energy storage module, at least two first output ends of the voltage control module are connected to the second end of each switching switch in the switching switch group, and the second output end of the voltage control module is connected to each selection switch in the multiple connection switch groups.

[0011] In one embodiment, the voltage quality control device further comprises a plurality of transformer groups, each transformer group comprising at least a first transformer and a second transformer; wherein:

[0012] One side of the first transformer is connected in parallel with the first selection switch, the first ends of the other sides of the first transformers are connected to the first ends of the first switching switch, and the second ends of the other sides of the first transformers are connected to the second output end of the voltage control module;

[0013] One side of the second transformer is connected in parallel with the second selection switch, the first ends of the other sides of the second transformers are connected to the first ends of the second switching switches, and the second ends of the other sides of the second transformers are connected to the second output end of the voltage control module.

[0014] In one embodiment, the voltage control module includes:

[0015] A voltage stabilizing circuit, connected in parallel with the energy storage module, for maintaining the stability of the output voltage;

[0016] A full-bridge circuit, connected to the voltage stabilizing circuit, for outputting a pulse voltage;

[0017] A filter circuit, wherein the multiple input terminals of the filter circuit are respectively connected to the multiple upper bridge arm midpoints of the full-bridge circuit, at least two first output terminals of the filter circuit form at least two first output terminals of the voltage control module, and the second output terminal of the filter circuit is connected to the lower bridge arm midpoint of the full-bridge circuit and forms the second output terminal of the voltage control module.

[0018] In one embodiment, the full-bridge circuit includes a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm connected in parallel; wherein the midpoint of the first bridge arm, the second bridge arm and the third bridge arm is the midpoint of the upper bridge arm of the full-bridge circuit, and the midpoint of the fourth bridge arm is the midpoint of the lower bridge arm of the full-bridge circuit.

[0019] In one embodiment, the filtering circuit comprises:

[0020] A first filtering unit, wherein an input end of the first filtering unit is connected to a bridge arm midpoint of a first bridge arm of the full-bridge circuit, and a first output end of the first filtering unit is a first output end of the voltage control module corresponding to a first phase;

[0021] a second filtering unit, wherein an input end of the second filtering unit is connected to a bridge arm midpoint of a second bridge arm of the full-bridge circuit, and a first output end of the second filtering unit is a first output end of the voltage control module corresponding to a second phase;

[0022] a third filtering unit, wherein an input end of the third filtering unit is connected to a bridge arm midpoint of a third bridge arm of the full-bridge circuit, and a first output end of the third filtering unit is a first output end of the voltage control module corresponding to a third phase;

[0023] The second output ends of the first filtering unit, the second filtering unit and the third filtering unit are connected to the midpoint of the fourth bridge arm to form the second output end of the voltage control module.

[0024] In one embodiment, any one of the first filter unit, the second filter unit, and the third filter unit includes a filter inductor and a filter capacitor, the connection point of the filter inductor and the filter capacitor is the first output end of the filter unit, and the other end of the filter capacitor forms the second output end of the filter unit.

[0025] In a second aspect, the present application further provides a voltage quality control method, which is applied to the above-mentioned voltage quality control device, and the method includes:

[0026] Determine the faulty phase feeder;

[0027] The selection switch connected to the faulty phase feeder is disconnected, and the switch corresponding to the faulty phase in the switch group is controlled to switch on the line corresponding to the faulty feeder, so as to output the target voltage through the voltage control module for voltage compensation.

[0028] In one embodiment, the method further comprises:

[0029] Determining the voltage amplitude dropped by the fault phase feeder;

[0030] The voltage control module is adjusted according to the voltage amplitude to control the voltage control module to output a target voltage.

[0031] In the above-mentioned voltage quality control device and method, the voltage control module can be connected to the phase feeder in series in a time-sharing manner by switching on and off the switching switch and the selection switch to realize dynamic voltage compensation of the feeder. The present application realizes the efficient management of transient voltage problems of multi-phase lines of multiple feeders by a single voltage control module by adding a switching switch between the voltage quality module and the phase feeder. The series side port is time-division multiplexed according to the voltage drop conditions of different feeders and different phases, which can greatly reduce the number of components in the circuit, reduce costs, and also reduce the idle rate of the voltage control module. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] FIG1 is a structural diagram of a voltage quality control device in one embodiment;

[0034] FIG2 is a structural diagram of a voltage quality control device in another embodiment;

[0035] FIG3 is a circuit diagram of a voltage control module;

[0036] Figure 4 A schematic diagram of the structure of a switching switch group in an embodiment;

[0037] Figure 5 It is a structural diagram of voltage management in one embodiment.

[0038] Description of reference numerals:

[0039] 11-connecting switch group, 12-switching switch group, 13-voltage control module, 14-energy storage module, 111-first selection switch, 112-second selection switch, 113-third selection switch, 121-first switching switch, 122-second switching switch, 123-third switching switch, 131-voltage stabilizing circuit, 132-full bridge circuit, 133-filtering circuit. DETAILED DESCRIPTION

[0040] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0042] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0043] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0044] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0045] As shown in FIG1 , a voltage quality control device of an embodiment includes a plurality of connection switch groups 11, a switching switch group 12 and a voltage control module 13. Each connection switch group 11 includes at least a first selection switch 111 and a second selection switch 112, wherein the first selection switch 111 is used to connect to the first phase feeder, and the second selection switch 112 is used to connect to the second phase feeder; the switching switch group 12 includes at least a first switching switch 121 and a second switching switch 122, wherein a plurality of first ends of the first switching switch 121 are respectively connected to the first selection switch 111 in each connection switch group 11; a plurality of first ends of the second switching switch 122 are respectively connected to the second selection switch 112 in each connection switch group 11; the voltage control module 13 is connected to the second end of each switching switch in the switching switch group 12 and each selection switch in the connection switch group 11, and is used to provide a compensation voltage.

[0046] It should be noted that the number of the connection switch groups 11 in the voltage quality control device can be the total number of feeders, or a number greater than 1 and less than the total number of feeders, such as M (M greater than 1), for voltage management of M feeders. Each feeder includes at least a first phase feeder and a second phase feeder. In some embodiments, the feeder also includes a third phase feeder. The phase feeder refers to a feeder corresponding to a certain phase. The feeder can be a medium voltage (such as 10KV) distribution network feeder.

[0047] In some embodiments, the gating switch may be a mechanical switch or an electronic switch, etc., for realizing the on and off of the circuit. For example, the gating switch may be realized by a device such as a relay or a bidirectional thyristor. Exemplarily, the gating switch may be a single-pole single-channel switch. It should be noted that the first gating switch 111 corresponds to the first phase, and the second gating switch 112 corresponds to the second phase, and the first phase and the second phase are different phases.

[0048] In some embodiments, a first phase feeder of the M feeders is connected to a first selection switch 111 , and a second phase feeder of the M feeders is connected to a second selection switch 112 .

[0049] In some embodiments, the switch group 12 includes a plurality of switches, and the number of switches is related to the number of phases of the feeder. For example, when the feeder includes a first phase feeder and a second phase feeder, the switch group 12 includes a first switch 121 and a second switch 122; when the feeder includes a first phase feeder, a second phase feeder, and a third phase feeder, the switch group 12 includes a first switch 121, a second switch 122, and a third switch 123. That is, the number of switches is equal to the number of phases, and one switch corresponds to one phase.

[0050] In some embodiments, each connecting switch group 11 also includes a third selection switch, which is used to connect to the third phase feeder; the switching switch group 12 also includes a third switching switch, and multiple first ends of the third switching switch are respectively connected to the third selection switch in each connecting switch group 11.

[0051] The number of the connection switch groups 11 is M, and the first switch 121, the second switch 122, and the third switch 123 each have M first ends. The first selection switch 111 in each connection switch group 11 is connected to one of the first ends of the first switch 121, the second selection switch 112 in each connection switch group 11 is connected to one of the first ends of the second switch 122, and the third selection switch in each connection switch group 11 is connected to one of the first ends of the third switch.

[0052] In the above embodiment, by providing three switching switches, time-sharing voltage compensation can be performed on the three-phase feeder lines respectively.

[0053] In some embodiments, the voltage control module 13 may be a single-phase voltage quality controller or a multi-phase voltage quality controller. The voltage quality controller may be a VQC (voltage quality controller) or a DVR (Dynamic Voltage Restorer).

[0054] In some embodiments, when the feeder includes a first phase feeder, a second phase feeder, and a third phase feeder, the voltage control module 13 may specifically be a three-phase voltage quality controller (Three-phase voltage quality controller, TP-VQC).

[0055] In some embodiments, the input end of the voltage control module 13 is connected to the energy storage module 14, at least two first output ends of the voltage control module 13 are connected to the second end of each switching switch in the switching switch group 12, and the second output end of the voltage control module 13 is connected to each selection switch in the multiple connection switch groups 11.

[0056] Exemplarily, as shown in Figure 1, multiple first ends of the first switching switch 121 are respectively connected to the first end of the first selection switch 111 in each connection switch group 11, and the second end of the first switching switch 121 is connected to one of the first output ends of the voltage control module 13; multiple first ends of the second switching switch 122 are respectively connected to the first end of the second selection switch 112 in each connection switch group 11, and the second end of the second switching switch 122 is connected to one of the first output ends of the voltage control module 13; the second ends of the first selection switch 111 and the second selection switch 112 are connected to the second output end of the voltage control module 13.

[0057] In some embodiments, when the feeder includes a first phase feeder, a second phase feeder, and a third phase feeder, each connection switch group 11 further includes a third gate switch, and the switch group 12 further includes a third switch. A plurality of first ends of the third switch are respectively connected to the first ends of the third gate switches in each connection switch group 11, and a second end of the third switch is connected to one of the first output ends of the voltage control module 13; the second ends of the first gate switch 111, the second gate switch 112, and the third gate switch are connected to the second output end of the voltage control module 13.

[0058] Thus, in the above embodiment, the voltage control module 13 can provide compensation voltages for the three phases of the plurality of feeders respectively.

[0059] In the above-mentioned voltage quality control device, the voltage control module can be connected to the phase feeder in series in time-sharing manner by switching on and off the switching switch and the selection switch to realize dynamic voltage compensation of the feeder. The present application realizes the efficient management of transient voltage problems of multi-phase lines of multiple feeders by a single voltage control module by adding a switching switch between the voltage quality module and the phase feeder. The series side port is time-division multiplexed according to the voltage drop conditions of different feeders and different phases, which can greatly reduce the number of components in the circuit, reduce costs, and also reduce the idle rate of the voltage control module.

[0060] In some embodiments, the voltage quality control device also includes multiple transformer groups, each transformer group includes at least a first transformer and a second transformer; wherein, one side of the first transformer is connected in parallel with the first selection switch 111, the first ends of the other sides of the multiple first transformers are connected to the multiple first ends of the first switching switch 121, and the second ends of the other sides of the multiple first transformers are connected to the second output end of the voltage control module 13; one side of the second transformer is connected in parallel with the second selection switch 112, the first ends of the other sides of the multiple second transformers are connected to the multiple first ends of the second switching switch 122, and the second ends of the other sides of the multiple second transformers are connected to the second output end of the voltage control module 13.

[0061] It can be understood that the number of transformer groups is the same as the number of connection switch groups 11, and is also the same as the number of first ends of the switching switches, both of which are M. The transformer group includes multiple transformers, such as at least a first transformer and a second transformer, or a first transformer, a second transformer, and a third transformer. In some embodiments, the transformer can specifically be an isolation transformer. The transformer plays the role of electrical isolation and voltage amplification.

[0062] One side of the first transformer is connected in parallel to the first gate switch 111, and one side of the second transformer is connected in parallel to the second gate switch 112. When the connection switch group 11 includes a third gate switch and the transformer group includes a third transformer, one side of the third transformer is connected in parallel to the third gate switch.

[0063] For each first transformer, the first end of the other side thereof is connected to one of the first ends of the first switch 121, that is, the first ends of the other side of the M first transformers are connected one-to-one with the M first ends of the first switch 121; for each second transformer, the first end of the other side thereof is connected to one of the first ends of the second switch 122, that is, the first ends of the other side of the M second transformers are connected one-to-one with the M first ends of the second switch 122. When the switch group 12 includes a third switch, and the transformer group includes a third transformer, for each third transformer, the first end of the other side thereof is connected to one of the first ends of the third switch, that is, the first ends of the other side of the M third transformers are connected one-to-one with the M first ends of the third switch. The second ends of the other sides of all transformers are connected to the second output end of the voltage control module 13.

[0064] Exemplarily, please refer to FIG. 2 , and take M as 3 for illustration. Each feeder includes three phase feeders, corresponding to phases A, B, and C; the connection switch group 11 includes a first selection switch 111, a second selection switch 112, and a third selection switch 113; the transformer group includes a first transformer, a second transformer, and a third transformer; the switching switch group 12 includes a first switching switch 121, a second switching switch 122, and a third switching switch 123. The first selection switch 111 is used to connect to the first phase feeder A, the second selection switch 112 is used to connect to the second phase feeder B, and the third selection switch 113 is used to connect to the third phase feeder C. For each feeder, the first selection switch 111 is connected in parallel with one side of a first transformer, the first end of the other side of the first transformer is connected to one of the first ends of the first switching switch 121, and the second end of the other side of the first transformer is connected to the second output end of the voltage control module 13; the second selection switch 112 is connected in parallel with one side of a second transformer, the first end of the other side of the second transformer is connected to one of the first ends of the second switching switch 122, and the second end of the other side of the second transformer is connected to the second output end of the voltage control module 13; the third selection switch 113 is connected in parallel with one side of a third transformer, the first end of the other side of the third transformer is connected to one of the first ends of the third switching switch 123, and the second end of the other side of the third transformer is connected to the second output end of the voltage control module 13. The second ends of the three switching switches are connected to the three first ends of the voltage control module 13 in a one-to-one correspondence. The energy storage module 14 is connected to the input end of the voltage control module 13 for providing electrical energy.

[0065] In the above embodiment, the switching switch is connected to the selection switch through a transformer, so that when the voltage control module is connected in series to the circuit, the voltage provided by the voltage control module can be amplified by the transformer to achieve compensation for the feeder voltage.

[0066] In some embodiments, the voltage control module 13 includes: a voltage stabilizing circuit 131, which is connected in parallel with the energy storage module 14 and is used to maintain the stability of the output voltage; a full-bridge circuit 132, which is connected to the voltage stabilizing circuit 131 and is used to output a pulse voltage; a filter circuit 133, wherein multiple input ends of the filter circuit 133 are respectively connected to multiple upper bridge arm midpoints of the full-bridge circuit 132, at least two first output ends of the filter circuit 133 form at least two first output ends of the voltage control module 13, and the second output end of the filter circuit 133 is connected to the lower bridge arm midpoint of the full-bridge circuit 132, and forms the second output end of the voltage control module 13.

[0067] Exemplarily, the voltage stabilizing circuit 131 may be a capacitor connected in parallel with the energy storage module 14, and is used to maintain the output voltage within a stable range when the voltage provided by the energy storage module 14 fluctuates. In other implementations, the voltage stabilizing circuit 131 may also be constructed by other devices, and the embodiments of the present application are not limited to this.

[0068] The full-bridge circuit 132 is connected to the voltage stabilizing circuit 131 for outputting a pulse voltage; the filter circuit 133 is connected to the full-bridge circuit 132 for filtering the pulse voltage to obtain a sinusoidal voltage.

[0069] In some embodiments, when the feeder only includes a first phase feeder and a second phase feeder, the full-bridge circuit 132 may include a first bridge arm, a second bridge arm, and a third bridge arm connected in parallel; wherein the midpoint of the first bridge arm and the second bridge arm is the midpoint of the upper bridge arm of the full-bridge circuit 132, and the midpoint of the third bridge arm is the midpoint of the lower bridge arm of the full-bridge circuit 132.

[0070] When the feeder includes a first phase feeder, a second phase feeder and a third phase feeder, the full-bridge circuit 132 can adopt a three-phase four-bridge arm structure, that is, it includes a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm connected in parallel; wherein the midpoint of the first bridge arm, the second bridge arm and the third bridge arm is the midpoint of the upper bridge arm of the full-bridge circuit 132, and the midpoint of the fourth bridge arm is the midpoint of the lower bridge arm of the full-bridge circuit 132.

[0071] In some embodiments, each bridge arm may be composed of two insulated gate bipolar transistors (IGBTs). It is understood that in other embodiments, the number of transistors included in each bridge arm may be more than two, and the type of transistor may also be other types, which is not limited in the embodiments of the present application.

[0072] It should be noted that the transistors constituting the bridge arm of the full-bridge circuit 132 are voltage-driven devices. If a positive voltage is applied to the gate of the transistor, the transistor can be turned on, and if a negative voltage is applied, the transistor can be turned off. Therefore, in order to realize the opening and closing of multiple transistors, a drive circuit can be configured for each transistor, and the drive circuit can output a forward voltage and / or a reverse voltage. In this way, if the voltage control module 13 is required to output a target voltage, a pulse signal can be controlled to be input to the drive circuit, and the drive circuit converts the pulse signal into a required voltage and applies it to the corresponding transistor to control the opening or closing of the transistor. In this way, the orderly opening and closing of the transistor is realized, so as to output the required pulse waveform. Then, a smooth sinusoidal voltage is obtained by filtering through the filter circuit 133, which is added to the power grid to achieve voltage compensation.

[0073] In some embodiments, the filter circuit 133 may be specifically formed by a filter inductor and / or a filter capacitor, and includes a plurality of input terminals, and at least two first output terminals and one second output terminal. Among them, the at least two first output terminals of the filter circuit 133 are the at least two first output terminals of the voltage control module 13, and the second output terminal of the filter circuit 133 is the second output terminal of the voltage control module 13.

[0074] In the above embodiment, the voltage control module 13 includes a voltage stabilizing circuit 131, a full-bridge circuit 132 and a filter circuit 133. The voltage output by the energy storage module 14 can be converted into a stable pulse voltage by driving the transistor in the full-bridge circuit 132, and then a smooth sinusoidal voltage is obtained after filtering by the filter circuit 133, so that feeder voltage compensation can be achieved.

[0075] In some embodiments, the filtering circuit 133 includes: a first filtering unit, the input end of the first filtering unit is connected to the midpoint of the first bridge arm of the full-bridge circuit 132, and the first output end of the first filtering unit is the first output end of the voltage control module 13 corresponding to the first phase; a second filtering unit, the input end of the second filtering unit is connected to the midpoint of the second bridge arm of the full-bridge circuit 132, and the first output end of the second filtering unit is the first output end of the voltage control module 13 corresponding to the second phase; a third filtering unit, the input end of the third filtering unit is connected to the midpoint of the third bridge arm of the full-bridge circuit 132, and the first output end of the third filtering unit is the first output end of the voltage control module 13 corresponding to the third phase; the second output ends of the first filtering unit, the second filtering unit, and the third filtering unit are connected to the midpoint of the fourth bridge arm to form the second output end of the voltage control module 13.

[0076] In some embodiments, any one of the first filter unit, the second filter unit, and the third filter unit includes a filter inductor and a filter capacitor, the connection point between the filter inductor and the filter capacitor is the first output end of the filter unit, and the other end of the filter capacitor forms the second output end of the filter unit.

[0077] In the above embodiment, by providing a plurality of filtering units, the voltage provided by each phase can be filtered, thereby realizing multi-feeder and multi-phase time-division multiplexing of the voltage control module 13 .

[0078] In some embodiments, the voltage control module 13 may be a three-phase voltage quality controller, and its circuit structure is shown in FIG3. Referring to FIG3, the voltage control module 13 is composed of four bridge arms a, b, c, and o and capacitors, filter inductors, and filter capacitors. In the bridge arm a, the emitter of S1 is connected to the collector of S2, and the node formed is connected to the filter inductor L fa In the bridge arm b, the emitter of S3 is connected to the collector of S4, and the node formed is connected to the filter inductor L fb In the bridge arm c, the emitter of S5 is connected to the collector of S6, and the node formed is connected to the filter inductor L fc In the bridge arm, the emitter of S7 is connected to the collector of S8, and the node formed is connected to the filter capacitor C fa , C fb , C fc The negative electrode of S1 is connected to the output port o. The collector of S1, the collector of S3, the collector of S5, and the collector of S7 are connected to the positive electrode of the capacitor C1 and the positive electrode of the energy storage module 14, and the emitters of S2, S4, S6, and S8 are connected to the negative electrode of the capacitor C1 and the negative electrode of the energy storage module 14. In addition, the filter inductor L fa One end of the filter capacitor C fa The positive pole is connected to the a-phase output port, and the filter inductor L fb One end of the filter capacitor C fb The positive pole is connected to the b-phase output port, and the filter inductor L fc One end of the filter capacitor C fc The positive pole is connected to the c-phase output port.

[0079] In this way, the output of three-phase voltages can be achieved through fewer ports, simplifying the circuit structure.

[0080] In some embodiments, the voltage quality control device further includes a controller connected to each of the gating switches and each of the switching switches, and configured to control the opening and closing of each of the gating switches and each of the switching switches.

[0081] In a specific embodiment, please refer to Figure 4The series side of the voltage quality control device includes a three-phase voltage quality controller (TP-VQC). The AC side of the TP-VQC is connected to the feeder in series through a switching switch and a selection switch, and is connected to the energy storage module 14 on the DC side.

[0082] Exemplarily, the switching switch group 12 includes 3 switching switches. Each switching switch includes M (for example, M is equal to 3) first ends and one second end. The input end of TP-VQC is connected to the energy storage module 14, and the three first output ends of TP-VQC are output end a, output end b and output end c, respectively, and one second output end is output end o. Specifically, the M first ends of the first switching switch SA are respectively connected to the same phase of the M feeders, that is, connected to the first ends on the other side of the M first transformers; the second end of the first switching switch SA is connected to the a end of TP-VQC. The M first ends of the second switching switch SB are respectively connected to the same phase of the M feeders, that is, connected to the first ends on the other side of the M second transformers; the second end of the second switching switch SB is connected to the b end of TP-VQC. The M first ends of the third switching switch SC are respectively connected to the same phase of the M feeders, that is, connected to the first ends on the other side of the M third transformers; the second end of the third switching switch SC is connected to the c end of TP-VQC. The second end of the other side of each transformer is connected to the o-end of TP-VQC.

[0083] The above embodiment provides a voltage quality control device that can realize time-sharing multiplexing of the voltage control module. Since the situation of simultaneous drop of multiple feeders is generally rare, the TP-VQC on the series side can be multiplexed, and the theoretical value can be at least 1, which is set as needed during practical application. It can be understood that the voltage control module is mainly responsible for realizing dynamic voltage compensation of the feeder. In order to reduce the idle rate of the power electronic device at the series port and reduce the cost of using the device, a switching switch is added between the voltage quality module and the feeder to achieve efficient management of transient voltage problems of three-phase lines of M feeders by a single VQC. According to the voltage drop problems of different feeders and different phases, the series side ports are time-sharing multiplexed, which can greatly reduce the number of components in the circuit and reduce costs.

[0084] The present application also provides a voltage quality control method, which is applied to the voltage quality control device provided in the above-mentioned embodiment, and the method specifically includes: determining a faulty phase feeder; disconnecting a selection switch connected to the faulty phase feeder, and controlling the switching switch corresponding to the faulty phase in the switching switch group 12 to switch on the line corresponding to the faulty feeder, so as to output a target voltage through the voltage control module 13 for voltage compensation.

[0085] Specifically, the sensor set in the line can detect whether there is a faulty phase feeder. If the voltage of a phase feeder is detected to be less than a preset threshold, it is considered that a faulty phase feeder has occurred, that is, the faulty feeder and the faulty phase where the voltage drop occurs are determined. Then, the selection switch connected to the faulty phase feeder can be disconnected by the controller or manually, and the switching switch that needs to be operated is determined according to the faulty phase, and the bidirectional thyristor that needs to be turned on in the switching switch is determined according to the faulty feeder, and the bidirectional thyristor is controlled to be turned on, so as to turn on the line corresponding to the faulty phase feeder, that is, the control voltage module is connected in series to the line to perform voltage compensation on the faulty phase feeder.

[0086] In some embodiments, the target voltage output by the voltage control module 13 is determined by: determining the voltage amplitude of the fault phase feeder drop; and adjusting the voltage control module 13 according to the voltage amplitude to control the voltage control module 13 to output the target voltage.

[0087] In some embodiments, the controller may determine the voltage amplitude of the fault phase feeder drop, and then adjust the voltage control module 13 according to the voltage amplitude to control the voltage control module 13 to output the target voltage. The voltage control module 13 may be adjusted by PWM (pulse width modulation).

[0088] In some embodiments, if the switching switch is directly connected to the enabling switch, the amplitude of the target voltage is the voltage amplitude of the fault phase drop; if the switching switch is connected to the enabling switch via a transformer, and the voltage amplification factor of the transformer is N, the amplitude of the target voltage is the voltage amplitude of the fault phase drop divided by N.

[0089] In some embodiments, the full-bridge circuit 132 in the voltage control module 13 is composed of a plurality of transistors, each transistor is configured with a drive circuit, and the drive circuit can output a forward voltage and / or a reverse voltage. In this way, if the voltage control module 13 is required to output a target voltage, a pulse signal can be input to the drive circuit, and the drive circuit converts the pulse signal into the required voltage and applies it to the corresponding transistor to control the opening or closing of the transistor. In this way, the orderly opening and closing of the transistor is realized to facilitate the output of the required pulse waveform. Then, a smooth sinusoidal voltage is obtained by filtering through the filter circuit 133, which is added to the power grid to achieve voltage compensation.

[0090] In the above embodiment, the voltage control module can be connected to the phase feeder in series in a time-sharing manner by switching on and off the switching switch and the selection switch to realize dynamic voltage compensation of the feeder. The present application realizes the efficient management of transient voltage problems of multi-phase lines of multiple feeders by a single voltage control module by adding a switching switch between the voltage quality module and the phase feeder. The series side port is time-division multiplexed according to the voltage drop conditions of different feeders and different phases, which can greatly reduce the number of components in the circuit, reduce costs, and also reduce the idle rate of the voltage control module.

[0091] Combine the following Figure 5 Conduct a case analysis for a specific situation:

[0092] For example, if a voltage sag fault is detected in phase A of feeder 1 and phase B of feeder 2, port a and port b of the voltage control module need to be activated, switch SA1 of switching switch SA and switch SB2 of switching switch SB need to be closed; and the selection switches of phase A of feeder 1 and phase B of feeder 2 are disconnected to connect the voltage control module to the feeder to realize dynamic voltage compensation.

[0093] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0094] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A voltage quality control device, characterized in that: include: A plurality of connection switch groups, each of the connection switch groups at least comprising a first gate switch and a second gate switch, wherein the first gate switch is used to connect to a first phase feeder, and the second gate switch is used to connect to a second phase feeder; a switching switch group, comprising at least a first switching switch and a second switching switch, wherein a plurality of first ends of the first switching switch are respectively connected to the first selection switches in each of the connection switch groups; a plurality of first ends of the second switching switch are respectively connected to the second selection switches in each of the connection switch groups; The voltage control module is connected to the second end of each switch in the switch group and each selection switch in the connection switch group, and is used to provide a compensation voltage.

2. The voltage quality control device according to claim 1, characterized in that: Each of the connecting switch groups further includes a third gating switch, which is used to connect to a third phase feeder; the switching switch group further includes a third switching switch, and multiple first ends of the third switching switch are respectively connected to the third gating switches in each of the connecting switch groups.

3. The voltage quality control device according to claim 1, characterized in that: The input end of the voltage control module is connected to the energy storage module, at least two first output ends of the voltage control module are connected to the second end of each switching switch in the switching switch group, and the second output end of the voltage control module is connected to each selection switch in the multiple connection switch groups.

4. The voltage quality control device according to claim 3, characterized in that: The voltage quality control device further comprises a plurality of transformer groups, each transformer group comprising at least a first transformer and a second transformer; wherein: One side of the first transformer is connected in parallel with the first selection switch, the first ends of the other sides of the first transformers are connected to the first ends of the first switching switch, and the second ends of the other sides of the first transformers are connected to the second output end of the voltage control module; One side of the second transformer is connected in parallel with the second selection switch, the first ends of the other sides of the second transformers are connected to the first ends of the second switching switches, and the second ends of the other sides of the second transformers are connected to the second output end of the voltage control module.

5. The voltage quality control device according to claim 3, characterized in that: The voltage control module comprises: A voltage stabilizing circuit, connected in parallel with the energy storage module, for maintaining the stability of the output voltage; A full-bridge circuit, connected to the voltage stabilizing circuit, for outputting a pulse voltage; A filter circuit, wherein the multiple input terminals of the filter circuit are respectively connected to the multiple upper bridge arm midpoints of the full-bridge circuit, at least two first output terminals of the filter circuit form at least two first output terminals of the voltage control module, and the second output terminal of the filter circuit is connected to the lower bridge arm midpoint of the full-bridge circuit and forms the second output terminal of the voltage control module.

6. The voltage quality control device according to claim 5, characterized in that: The full-bridge circuit includes a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm connected in parallel; wherein the midpoints of the first bridge arm, the second bridge arm and the third bridge arm are the midpoints of the upper bridge arm of the full-bridge circuit, and the midpoint of the fourth bridge arm is the midpoint of the lower bridge arm of the full-bridge circuit.

7. The voltage quality control device according to claim 6, characterized in that: The filtering circuit comprises: A first filtering unit, wherein an input end of the first filtering unit is connected to a bridge arm midpoint of a first bridge arm of the full-bridge circuit, and a first output end of the first filtering unit is a first output end of the voltage control module corresponding to a first phase; a second filtering unit, wherein an input end of the second filtering unit is connected to a bridge arm midpoint of a second bridge arm of the full-bridge circuit, and a first output end of the second filtering unit is a first output end of the voltage control module corresponding to a second phase; a third filtering unit, wherein an input end of the third filtering unit is connected to a bridge arm midpoint of a third bridge arm of the full-bridge circuit, and a first output end of the third filtering unit is a first output end of the voltage control module corresponding to a third phase; The second output ends of the first filtering unit, the second filtering unit and the third filtering unit are connected to the midpoint of the fourth bridge arm to form the second output end of the voltage control module.

8. The voltage quality control device according to claim 7, characterized in that: Any one of the first filter unit, the second filter unit, and the third filter unit includes a filter inductor and a filter capacitor, the connection point of the filter inductor and the filter capacitor is the first output end of the filter unit, and the other end of the filter capacitor forms the second output end of the filter unit.

9. A voltage quality control method, characterized in that: Applied to the voltage quality control device according to any one of claims 1 to 8, the method comprises: Determine the faulty phase feeder; The selection switch connected to the faulty phase feeder is disconnected, and the switch corresponding to the faulty phase in the switch group is controlled to switch on the line corresponding to the faulty feeder, so as to output the target voltage through the voltage control module for voltage compensation.

10. The method according to claim 9, characterized in that The method further comprises: Determining the voltage amplitude dropped by the fault phase feeder; The voltage control module is adjusted according to the voltage amplitude to control the voltage control module to output a target voltage.

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