Voltage compensator and power supply system
By reducing the number of thyristors and taps in the energy extraction transformer, a voltage compensator is constructed, which solves the problem of high cost of dynamic voltage restorers, achieves stability and safety of load voltage, and reduces equipment cost and design complexity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2026-03-27
AI Technical Summary
In existing technologies, dynamic voltage restorers use high-power insulated gate bipolar transistor modules and complex filtering circuits, resulting in high costs. Traditional voltage management methods involve a large workload and require a large equipment footprint, making them difficult to promote.
A voltage compensator is used by reducing the number of thyristors and taps on the energy extraction transformer. The voltage compensator is constructed using an energy extraction transformer, a thyristor bridge circuit, and a compensation transformer to control the load voltage within a preset range.
It effectively reduces the cost of voltage compensators while ensuring load voltage stability and safety, simplifies the enclosure wiring design, and reduces the difficulty of insulation design.
Smart Images
Figure CN224053897U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of power supply, and particularly relates to a voltage compensator and a power supply system. BACKGROUND
[0002] The problems of large voltage fluctuation and low voltage at the end of distribution network lines are particularly common at the end of rural distribution networks and part of urban distribution networks. The access of new energy such as wind power and photovoltaic power will also cause fluctuations in the power grid. Under the requirement of building a new power system, power quality management is particularly important.
[0003] Traditional voltage management methods mainly include: 1. installing distribution transformers at the end of the line, that is, adding new transformers; 2. transforming branch lines, such as increasing the cross section of the cable or adding a dedicated power supply; 3. transforming on-load voltage regulating transformers, such as expanding capacity and appropriately adjusting taps; 4. installing low-voltage automatic compensation capacitors for reactive power compensation; 5. installing AC voltage stabilizers. The above-mentioned traditional voltage management methods have limited adjustment capacity, large workload, and problems such as difficulty in negotiating the land area occupied by new equipment and line corridor, and are not easy to promote.
[0004] Therefore, at present, a dynamic voltage restorer (DVR) is mainly used to compensate the line on which the load is connected. However, the dynamic voltage restorer uses a high-power insulated gate bipolar transistor (IGBT) module, the filter circuit matched with the IGBT uses a high-cost capacitor inductor, the control system of the IGBT is complex, and the storage unit of the dynamic voltage restorer is also high in cost, thereby resulting in high cost of the dynamic voltage restorer. CONTENT OF THE UTILITY MODEL
[0005] The technical problem to be solved by the application is to solve the above-mentioned problems existing in the prior art, and to provide a voltage compensator and a power supply system. The use of the voltage compensator can effectively reduce the number of thyristors and the number of energy-taking transformer tap positions. Compared with the dynamic voltage restorer in the prior art, the voltage compensator provided in the application embodiment can effectively reduce the cost.
[0006] In a first aspect, the application embodiment provides a voltage compensator, which comprises N energy-taking transformers, N thyristor bridge circuits, N compensation transformers and a first controller, the energy-taking transformers and the thyristor bridge circuits correspond to the compensation transformers one by one, and N is a positive integer.
[0007] Each power taking transformer has its primary winding connected to a power supply line of a corresponding load, and has its secondary winding connected to a corresponding thyristor bridge circuit, for obtaining power from a power grid connected to the corresponding power supply line and converting the power into a target compensation voltage when the corresponding thyristor bridge circuit is in a target position;
[0008] A first controller is connected to each thyristor bridge circuit, for controlling each thyristor bridge circuit to be in a target position.
[0009] Each compensation transformer has its secondary winding connected to a corresponding power supply line.
[0010] Each thyristor bridge circuit and a corresponding compensation transformer are configured to transmit the target compensation voltage to compensate for a load current voltage of the load, so as to control the load current voltage to be within a preset range.
[0011] In some embodiments of the first aspect, each thyristor bridge circuit comprises a first thyristor unit to an nth thyristor unit; the first thyristor unit comprises a first thyristor group and an (n+1)th thyristor group, the second thyristor unit comprises a second thyristor group and an (n+2)th thyristor group, and the nth thyristor unit comprises an nth thyristor group and a 2nth thyristor group.
[0012] The primary winding of each power taking transformer comprises a first tap to an nth tap; and the secondary winding of each power taking transformer comprises an (n+1)th tap to an mth tap; wherein m is a positive integer greater than n.
[0013] The first end and the second end of each first thyristor unit to each nth thyristor unit are connected in series with the two ends of the primary winding of a corresponding compensation transformer.
[0014] The third end of each ith thyristor unit is connected to a corresponding ith tap, where i is an integer greater than or equal to 1 and less than or equal to n.
[0015] Each mth tap is grounded, and one of the (n+1)th tap to the (m-1)th tap is connected to a power supply line of a load connected to a corresponding power taking transformer.
[0016] In some embodiments of the first aspect, each of the first thyristor group to the 2nth thyristor group comprises two thyristors in a unidirectional anti-parallel connection.
[0017] In some embodiments of the first aspect, the voltage compensator further comprises:
[0018] at least one protection module, each protection module being connected in parallel with the corresponding thyristor bridge circuit and between the primary side of the corresponding compensation transformer;
[0019] a second controller connected to the at least one protection module, for controlling the on or off of each protection module, so as to prevent the short circuit of the corresponding secondary side tap of the power supply transformer of the protection module during the switching process of the corresponding thyristor bridge circuit.
[0020] In some embodiments of the first aspect, the second controller is specifically configured to:
[0021] in the case of the target gear of each power supply transformer, controlling the on of the corresponding protection module of each power supply transformer, or controlling the off of each protection module;
[0022] The first controller is specifically configured to:
[0023] in the case of the target gear of each power supply transformer, controlling the off of the first to n-th thyristor groups, or controlling the on of one of the first to n-th thyristor groups corresponding to each power supply transformer, controlling the on of one of the n+1-th to 2n-th thyristor groups corresponding to each power supply transformer, and controlling the off of the remaining thyristor groups.
[0024] In some embodiments of the first aspect, n = 4;
[0025] The second controller is specifically configured to:
[0026] in the case of the target gear being the zeroth gear, controlling the on of the protection module corresponding to each power supply transformer;
[0027] in the case of the target gear being the first to twelfth gears, controlling the off of the protection module corresponding to each power supply transformer;
[0028] The first controller is specifically configured to:
[0029] in the case of the target gear being the zeroth gear, controlling the off of the first to eighth thyristor groups corresponding to each power supply transformer;
[0030] in the case of the target gear being the first gear, controlling the on of the third and eighth thyristor groups corresponding to each power supply transformer, and controlling the off of the remaining thyristor groups;
[0031] in the case of the target gear being the second gear, controlling the on of the first and sixth thyristor groups corresponding to each power supply transformer, and controlling the off of the remaining thyristor groups;
[0032] In the case that the target gear is the third gear, the second thyristor group and the seventh thyristor group corresponding to each power take-off transformer are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off.
[0033] In the case that the target gear is the fourth gear, the second thyristor group and the eighth thyristor group corresponding to each power take-off transformer are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off.
[0034] In the case that the target gear is the fifth gear, the first thyristor group and the seventh thyristor group corresponding to each power take-off transformer are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off.
[0035] In the case that the target gear is the sixth gear, the first thyristor group and the eighth thyristor group corresponding to each power take-off transformer are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off.
[0036] In the case that the target gear is the seventh gear, the fourth thyristor group and the seventh thyristor group corresponding to each power take-off transformer are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off.
[0037] In the case that the target gear is the eighth gear, the second thyristor group and the fifth thyristor group corresponding to each power take-off transformer are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off.
[0038] In the case that the target gear is the ninth gear, the third thyristor group and the sixth thyristor group corresponding to each power take-off transformer are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off.
[0039] In the case that the target gear is the tenth gear, the fourth thyristor group and the sixth thyristor group corresponding to each power take-off transformer are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off.
[0040] In the case that the target gear is the eleventh gear, the third thyristor group and the fifth thyristor group corresponding to each power take-off transformer are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off.
[0041] In the case that the target gear is the twelfth gear, the fourth thyristor group and the fifth thyristor group corresponding to each power take-off transformer are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off.
[0042] In some embodiments of the first aspect, each protection module comprises a current limiting reactor and a group of thyristors connected in series between the primary side of the corresponding compensation transformer, and the group of thyristors S0 is connected to the second controller.
[0043] In some embodiments of the first aspect, the group of thyristors comprises two thyristors connected in anti-parallel.
[0044] In some embodiments of the first aspect, each compensation transformer comprises an isolation transformer.
[0045] In some embodiments of the first aspect, the voltage compensator further comprises:
[0046] a third controller connected to each of the energy extraction transformers, respectively, for controlling each of the energy extraction transformers to obtain power from a power grid to which the energy extraction transformer is connected to the corresponding power supply line, when it is monitored that the load current voltage of the load is less than the preset voltage and the bridge arm current of each of the thyristor bridge circuits is completely zero-crossed.
[0047] In some embodiments of the first aspect, the first controller is multiplexed as the third controller.
[0048] In a second aspect, the embodiments of the present application further provide a power supply system, comprising:
[0049] a load;
[0050] a power supply line connected to the load for supplying power to the load;
[0051] a voltage compensator according to any one of the first aspect connected to the power supply line for compensating the load current voltage to control the voltage of the load to be within the preset range.
[0052] Since the number of thyristor groups and the number of transformer taps can be effectively reduced in the topology with the same number of compensation gears by the thyristor bridge circuit, the voltage compensator and the control method thereof and the power supply system provided by the embodiments of the present application can ensure that n*(n-1)+1 gears are provided to compensate the load current voltage, thereby controlling the voltage of the load to be within the preset range, so that the voltage of the load is kept stable, ensuring the safety of the load, while effectively reducing the number of thyristors and the number of gear taps of the energy extraction transformer, and compared with the dynamic voltage restorer in the prior art, the voltage compensator provided by the embodiments of the present application can effectively reduce the cost. BRIEF DESCRIPTION OF DRAWINGS
[0053] Figure 1 FIG. 1 shows a structure schematic diagram of a power supply system provided by the embodiments of the present application;
[0054] Figure 2 FIG. 2 shows another structure schematic diagram of a power supply system provided by the embodiments of the present application;
[0055] Figure 3 FIG. 3 shows a simulation diagram of a trigger signal of a first thyristor S1 in a voltage compensator provided by the embodiments of the present application;
[0056] Figure 4Fig. 6 shows a simulation diagram of the trigger signal of the fourth thyristor S4 in the voltage compensator provided by the embodiment of the present application;
[0057] Figure 5 Fig. 7 shows a simulation diagram of the trigger signal of the eighth thyristor S8 in the voltage compensator provided by the embodiment of the present application;
[0058] Figure 6 Fig. 8 shows a simulation diagram of the voltage compensation of the load by the voltage compensator provided by the embodiment of the present application.
[0059] Reference signs:
[0060] 10, protection module; 20, thyristor bridge circuit; 21, first thyristor bridge circuit; 22, second thyristor bridge circuit; 23, third thyristor bridge circuit; 30, power taking transformer; T 1a , A-phase power taking transformer; T 1b , B-phase power taking transformer; T 1c , C-phase power taking transformer; 40, compensation transformer; T 2a , A-phase compensation transformer; T 2b , B-phase compensation transformer; T 2c , C-phase compensation transformer; 50, load; L, current limiting reactor; S0, first thyristor group; S1, first thyristor group; S2, second thyristor group; S3, third thyristor group; S4, fourth thyristor group; S5, fifth thyristor group; S6, sixth thyristor group; S7, seventh thyristor group; S8, eighth thyristor group. DETAILED DESCRIPTION
[0061] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in combination with the drawings and embodiments.
[0062] The features and exemplary embodiments of various aspects of the present application will be described in detail below, and in order to make the purposes, technical solutions and advantages of the present application more clear and apparent, the present application will be further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application and are not configured to limit the present application. The present application can be implemented without some of these specific details by those skilled in the art. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.
[0063] It should be noted that, in this document, the terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between such entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or device. Without more limitations, the elements defined by the statement "include" do not exclude the presence of other identical elements in the process, method, article or device including the elements.
[0064] It should be understood that the term "and / or" used herein is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this document generally represents an "or" relationship between the front and rear associated objects.
[0065] Embodiment 1
[0066] The voltage compensator provided by the embodiments of the present application can be applied to the process of the power supply system supplying power to the load.
[0067] As shown in Figure 1 and Figure 2 , taking N=3 and N=1 as examples, the voltage compensator provided by the embodiments of the present application includes N energy-taking transformers 30, N thyristor bridge circuits 20, N compensation transformers 40 and a first controller, the energy-taking transformers 30 and the thyristor bridge circuits 20 correspond to the compensation transformers 40 one by one, and N is a positive integer.
[0068] As an example, as shown in Figure 1 , for the convenience of description, in the embodiments of the present application, the three energy-taking transformers 30 are respectively denoted as an A-phase energy-taking transformer T 1a , a B-phase energy-taking transformer T 1b and a C-phase energy-taking transformer T 1c , the three thyristor bridge circuits 20 are respectively denoted as a first thyristor bridge circuit 21, a second thyristor bridge circuit 22 and a third thyristor bridge circuit 23, and the three compensation transformers 40 are respectively denoted as an A-phase compensation transformer T 2a , a B-phase compensation transformer T 2b and a C-phase compensation transformer T 2c . The A-phase energy-taking transformer T 1a , the first thyristor bridge circuit 21 correspond to the A-phase compensation transformer T 2aCorresponding; Phase B power extraction transformer T 1b The second thyristor bridge circuit 22 is connected to the B-phase compensation transformer T. 2b Corresponding; C-phase power extraction transformer T 1c The third thyristor bridge circuit 23 is connected to the C-phase compensation transformer T. 2c correspond.
[0069] As another example, such as Figure 2 As shown, the energy extraction transformer 30 and the thyristor bridge circuit 20 correspond one-to-one with the compensation transformer 40.
[0070] For example, the compensation transformer 40 is used to achieve electrical isolation between the thyristor bridge circuit 20 and the power supply line, and also to magnetically couple the target compensation voltage from the thyristor bridge circuit 20 to the power supply line.
[0071] It should be noted that the value of N can be set according to the actual situation, and is not limited here.
[0072] It is worth mentioning that both the energy extraction transformer 30 and the compensation transformer 40 are mainly suitable for distribution networks of 10KV and below. The specific capacity and compensation depth of both are calculated and selected according to the user load conditions.
[0073] Each energy-harvesting transformer 30 has its primary winding adjustablely connected to the power supply line of its corresponding load 50, and its secondary taps connected to its corresponding thyristor bridge circuit 20. These are used to obtain electrical energy from the power grid connected to their respective power supply lines, and to convert the electrical energy into the target compensation voltage when the corresponding thyristor bridge circuit is in the target tap position. The number of taps on the secondary side of each energy-harvesting transformer is n, where n is a positive integer. The target compensation voltage is the compensation voltage corresponding to the target tap position, and the target tap position is the compensation tap position corresponding to the current voltage of the load among n*(n-1)+1 tap positions.
[0074] For example, such as Figure 1 As shown, the power supply lines for load 50 include phase A, phase B, and phase C. Phase A power transformer T... 1a The primary winding is adjustablely connected to the A-phase power supply line of its corresponding load 50, and the A-phase power extraction transformer T 1a The secondary taps are connected to the first thyristor bridge circuit 21 respectively; the B-phase power transformer T 1b The primary winding is adjustablely connected to the corresponding load 50's B-phase power supply line, and the B-phase power extraction transformer T 1b The secondary taps are respectively connected to the second thyristor bridge circuit 22; the C-phase power extraction transformer T 1c The primary winding is adjustablely connected to the corresponding 50% load C-phase power supply line, and the C-phase power extraction transformer T1c The secondary side taps are respectively connected to the third thyristor bridge circuit 23.
[0075] The first controller is connected to each thyristor bridge circuit 20 and is used to control each thyristor bridge circuit 20 to be in the target position.
[0076] Each thyristor bridge circuit 20 is connected to the primary side of its corresponding compensation transformer 40.
[0077] For example, such as Figure 1 As shown, the first thyristor bridge circuit 21 and the A-phase compensation transformer T 2a The primary side connection; the second thyristor bridge circuit 22 and the B-phase compensation transformer T 2b The primary side connection; the third thyristor bridge circuit 23 and the C-phase compensation transformer T 2c The first-side connection.
[0078] Each compensation transformer 40 has its secondary side connected to its corresponding power supply line.
[0079] For example, such as Figure 1 As shown, the A-phase compensation transformer T 2a The secondary side is connected to its corresponding A-phase power supply line; the B-phase compensation transformer T 2b The secondary side is connected to its corresponding B-phase power supply line; the C-phase compensation transformer T 2c The secondary side is connected to its corresponding C-phase power supply line.
[0080] Each thyristor bridge circuit and its corresponding compensation transformer are used to transmit the target compensation voltage to compensate the current load voltage, thereby controlling the load voltage within a preset range.
[0081] For example, the preset range can be considered to be the allowable deviation of the voltage of load 50. The preset range can be set according to the actual situation and is not limited here. For example, the preset range can be [0.9V1, 1.1V1], where V1 is the rated load voltage of load 50.
[0082] For example, the A-phase power extraction transformer T 1a The first electrical energy is obtained from the power grid connected to its corresponding A-phase power supply line, and then at the A-phase energy extraction transformer T 1a When the corresponding first thyristor bridge circuit 21 is in the target position, it converts the first electrical energy into the target A-phase compensation voltage. Then, through the A-phase power extraction transformer T... 1a The corresponding first thyristor bridge circuit 21, and the A-phase power extraction transformer T 1a The corresponding A-phase compensation voltage transformer T 2a Transformer T that draws energy from phase A 1aThe corresponding A-phase supply line outputs a target A-phase compensation voltage to compensate the current A-phase voltage of the load 50, thereby controlling the voltage of the load 50 to be within a preset range. The B-phase energy-taking transformer T 1b and the C-phase energy-taking transformer T 1c The implementation process is similar to the above-mentioned implementation process, and will not be described here.
[0083] In the topology with the same number of compensation gears, the thyristor bridge circuit can effectively reduce the number of thyristor groups and the number of transformer taps. Therefore, according to the voltage compensator provided in the embodiments of the present application, by adopting the dynamic voltage restorer, the thyristor bridge circuit and the compensation transformer to construct the voltage compensator, n*(n-1)+1 gears are provided to compensate the current voltage of the load, thereby controlling the voltage of the load to be within a preset range, so that the voltage of the load remains stable, ensuring the safe operation of the load, while effectively reducing the number of thyristors and the number of gear taps of the energy-taking transformer. Compared with the dynamic voltage restorer in the prior art, the voltage compensator provided in the embodiments of the present application can effectively reduce the cost.
[0084] It should be noted that, for example, the topology Figure 2 shown in FIG. 8 can output a compensation depth of ±30%, with 5% as one gear, a total of 13 gears, and only 8 groups of bidirectional anti-parallel thyristor groups are required, and the number of transformer taps is 4, which can be realized. If the bridge circuit is not used, the number of output gears is the same as the number of thyristor groups and transformer taps.
[0085] In addition, the voltage compensator provided in the embodiments of the present application has simpler box connection, which can effectively reduce the design cost and make the insulation design easier to implement.
[0086] In some embodiments, as shown in FIGS. 8 and 9, Figure 1 and Figure 2 the voltage compensator further comprises:
[0087] at least one protection module 10, each protection module 10 being connected in parallel with the corresponding thyristor bridge circuit 20 between the two ends of the primary side of the corresponding compensation transformer 40;
[0088] a second controller connected to the at least one protection module 10, for controlling the conduction or cutoff of each protection module, so as to prevent the secondary side gear tap of the corresponding energy-taking transformer of the protection module from being short-circuited during the gear switching of the corresponding thyristor bridge circuit.
[0089] Exemplarily, as shown in FIGS. 8 and 9, Figure 1As shown, the voltage compensator comprises 3 protection modules 10, for the convenience of description, the 3 protection modules 10 are respectively denoted as a first protection module 11, a second protection module 12 and a third protection module 13. Among them, the first protection module 11 is connected in parallel between the two ends of the primary side of the A-phase compensation transformer T 2a , the second protection module 12 is connected in parallel between the two ends of the primary side of the B-phase compensation transformer T 2b , and the third protection module 13 is connected in parallel between the two ends of the primary side of the C-phase compensation transformer T 2c .
[0090] More specifically, during the switching process of the thyristor bridge circuit 20 corresponding to each protection module 10, the second controller controls each protection module 10 to be cut off to prevent the secondary side tap of the power supply transformer 30 corresponding to the protection module 10 from being short-circuited.
[0091] In some examples, each thyristor bridge circuit 20 comprises a first thyristor unit to an n-th thyristor unit; the first thyristor unit comprises a first thyristor group and an n+1-th thyristor group, the second thyristor unit comprises a second thyristor group and an n+2-th thyristor group, and the n-th thyristor unit comprises an n-th thyristor group and a 2n-th thyristor group;
[0092] The primary side winding of each power supply transformer comprises a first tap to an n-th tap; the secondary side winding of each power supply transformer comprises an n+1-th tap to an m-th tap; wherein m is a positive integer greater than n;
[0093] The first end and the second end of each first thyristor unit to each n-th thyristor unit are respectively connected in series with the two ends of the primary side of the compensation transformer corresponding thereto;
[0094] The third end of each i-th thyristor unit is connected to the i-th tap corresponding thereto, i is an integer greater than or equal to 1 and less than or equal to n;
[0095] Each m-th tap is grounded, and one of each n+1-th tap to each m-1-th tap is adjustably connected to the power supply circuit of the load connected to the power supply transformer corresponding thereto.
[0096] As an example, each thyristor group in the first thyristor group to the 2n-th thyristor group comprises two thyristors in unidirectional anti-parallel connection. Among them, the two thyristors in unidirectional anti-parallel connection can be unidirectionally conductive, and the cathode of one thyristor is connected to the anode of the other thyristor, and the anode of one thyristor is connected to the cathode of the other thyristor.
[0097] As another example, each thyristor group in the first thyristor group to the 2n-th thyristor group comprises at least one bidirectional thyristor.
[0098] In some examples, the second controller is specifically configured to:
[0099] In the case that the target gear corresponds to each of the energy extraction transformers, the control unit controls each of the protection modules to be turned on, or controls each of the protection modules to be turned off.
[0100] The first controller is specifically configured to:
[0101] In the case that the target gear corresponds to each of the energy extraction transformers 30, the first controller controls each of the first to nth thyristor groups to be turned off, or controls one of the first to nth thyristor groups corresponding to each of the energy extraction transformers 30 to be turned on, controls one of the nth+1 to 2nth thyristor groups corresponding to each of the energy extraction transformers 30 to be turned on, and controls the remaining thyristor groups to be turned off.
[0102] That is, in the present embodiment, the first controller controls the protection modules 10 to be turned on or turned off, and controls each of the first to 2nth thyristor groups to be turned on or turned off, so that the thyristor bridge circuits 20 corresponding to each of the energy extraction transformers 30 are in the target gear.
[0103] In some more specific examples, n = 4.
[0104] The second controller is specifically configured to:
[0105] In the case that the target gear is the zeroth gear, the second controller controls each of the protection modules 10 corresponding to each of the energy extraction transformers 30 to be turned on.
[0106] In the case that the target gear is the first to twelfth gears, the second controller controls each of the protection modules 10 corresponding to each of the energy extraction transformers 30 to be turned off.
[0107] The first controller is specifically configured to:
[0108] In the case that the target gear is the zeroth gear, the first controller controls each of the first to eighth thyristor groups S1-S8 corresponding to each of the energy extraction transformers 30 to be turned off.
[0109] In the case that the target gear is the first gear, the first controller controls the third and eighth thyristor groups S3 and S8 corresponding to each of the energy extraction transformers 30 to be turned on, and controls the remaining thyristor groups to be turned off.
[0110] In the case that the target gear is the second gear, the first controller controls the first and sixth thyristor groups S1 and S6 corresponding to each of the energy extraction transformers 30 to be turned on, and controls the remaining thyristor groups to be turned off.
[0111] In the case that the target gear is the third gear, the first controller controls the second and seventh thyristor groups S2 and S7 corresponding to each of the energy extraction transformers 30 to be turned on, and controls the remaining thyristor groups to be turned off.
[0112] In the case that the target gear is the fourth gear, the second thyristor group S2 and the eighth thyristor group S8 corresponding to each power take-off transformer 30 are controlled to be turned on, and the remaining thyristor groups are controlled to be turned off;
[0113] In the case that the target gear is the fifth gear, the first thyristor group S1 and the seventh thyristor group S7 corresponding to each power take-off transformer 30 are controlled to be turned on, and the remaining thyristor groups are controlled to be turned off;
[0114] In the case that the target gear is the sixth gear, the first thyristor group S1 and the eighth thyristor group S8 corresponding to each power take-off transformer 30 are controlled to be turned on, and the remaining thyristor groups are controlled to be turned off;
[0115] In the case that the target gear is the seventh gear, the fourth thyristor group S4 and the seventh thyristor group S7 corresponding to each power take-off transformer 30 are controlled to be turned on, and the remaining thyristor groups are controlled to be turned off;
[0116] In the case that the target gear is the eighth gear, the second thyristor group S2 and the fifth thyristor group S5 corresponding to each power take-off transformer 30 are controlled to be turned on, and the remaining thyristor groups are controlled to be turned off;
[0117] In the case that the target gear is the ninth gear, the third thyristor group S3 and the sixth thyristor group S6 corresponding to each power take-off transformer 30 are controlled to be turned on, and the remaining thyristor groups are controlled to be turned off;
[0118] In the case that the target gear is the tenth gear, the fourth thyristor group S4 and the sixth thyristor group S6 corresponding to each power take-off transformer 30 are controlled to be turned on, and the remaining thyristor groups are controlled to be turned off;
[0119] In the case that the target gear is the eleventh gear, the third thyristor group S3 and the fifth thyristor group S5 corresponding to each power take-off transformer 30 are controlled to be turned on, and the remaining thyristor groups are controlled to be turned off;
[0120] In the case that the target gear is the twelfth gear, the fourth thyristor group S4 and the fifth thyristor group S5 corresponding to each power take-off transformer 30 are controlled to be turned on, and the remaining thyristor groups are controlled to be turned off.
[0121] That is, when n = 4, as Figure 1 and Figure 2As shown, each thyristor bridge circuit 20 includes first to fourth thyristor units; the first thyristor unit includes a first thyristor group S1 and a fifth thyristor group S5, the second thyristor unit includes a second thyristor group S2 and a sixth thyristor group S6, the third thyristor unit includes a third thyristor group S3 and a seventh thyristor group S7, and the fourth thyristor unit includes a fourth thyristor group S4 and an eighth thyristor group S8; the primary winding of each power supply transformer 30 includes a first tap, a second tap, a third tap and a fourth tap; the secondary winding of each power supply transformer 30 includes a fifth tap, a sixth tap, a seventh tap and an eighth tap; each first thyristor unit is connected to the corresponding first tap, each second thyristor unit is connected to the corresponding second tap, each third thyristor unit is connected to the corresponding third tap, and each fourth thyristor unit is connected to the corresponding fourth tap; the eighth tap is grounded, and one of the fifth tap to the seventh tap is adjustably connected to the power supply line of the load connected to the corresponding power supply transformer 30.
[0122] For example, refer to Figure 1 and Figure 2 For example, the first thyristor unit of the first thyristor bridge circuit 21 is connected to the first tap of the A-phase power supply transformer T 1a , the second thyristor unit of the first thyristor bridge circuit 21 is connected to the second tap of the A-phase power supply transformer T 1a , the third thyristor unit of the first thyristor bridge circuit 21 is connected to the third tap of the A-phase power supply transformer T 1a , the fourth thyristor unit of the first thyristor bridge circuit 21 is connected to the fourth tap of the A-phase power supply transformer T 1a , the eighth lead of the A-phase power supply transformer T 1a is grounded, and one of the fifth tap, the sixth tap and the seventh tap of the A-phase power supply transformer T 1a is adjustably connected to the A-phase power supply line. The connection principles of the second thyristor bridge circuit 22 and the third thyristor bridge circuit 23 are similar to those of the first thyristor bridge circuit 21, and are not described herein again.
[0123] For example, when n=4, the first tap of each power supply transformer 30 is 0, the second tap is 10% of the rated voltage of the load, the third tap is 25% of the rated voltage of the load, and the fourth tap is 30% of the rated voltage of the load, and eight pairs of unidirectional anti-parallel thyristors are controlled to be compensated in 13 positions in total, with one position set for every 5%, and the compensation range is ±30%. The corresponding conducting thyristors of each position are set as shown in Table 1.
[0124] Table 1
[0125] Gear Corresponding conducting thyristor 0 S0 5％ S3, S8 10％ S1, S6 15％ S2, S7 20％ S2, S8 25％ S1, S7 30％ S1, S8 -5％ S4, S7 -10％ S2, S5 -15％ S3, S6 -20％ S4, S6 -25％ S3, S5 -30％ S4, S5
[0126] It should be noted that the thyristors not mentioned in Table 1 are in the off state. For example, when the gear is 0, S1-S8 are in the off state. Gear 0 is the zeroth gear, gear 5% is the first gear, gear 10% is the second gear, and so on. Gear -30% is the twelfth gear. Table 1 takes 5% as an example of the compensation step, and in actual implementation, the compensation step can be other values, which are not limited here.
[0127] In some examples, each compensation transformer 40 includes an isolation transformer.
[0128] In some examples, each protection module 10 includes a current limiting reactor L and a group of alpha thyristors S0 connected in series between the two ends of the primary side of its corresponding compensation transformer 40.
[0129] Referring to Figure 1 and Figure 2 , the first protection module 11 includes a current limiting resistor L and a group of alpha thyristors S0 connected in series between the two ends of the primary side of the A-phase compensation transformer T 2a . The second protection module 12 and the third protection module 13 are similar to the first protection module 11, and will not be described here.
[0130] Exemplarily, the group of alpha thyristors S0 includes two thyristors connected in anti-parallel in one direction.
[0131] Exemplarily, the second controller is configured to control the group of alpha thyristors S0 to be on or off.
[0132] It should be noted that the use of the protection module 10 can be controlled by the switching of the group of alpha thyristors S0. The current limiting reactor L is used to limit the excessive short-circuit current generated when the bypass is switched, thereby damaging the control gear group of thyristors in the corresponding thyristor bridge circuit 20.
[0133] In some embodiments, the first controller is further configured to:
[0134] obtain the current voltage and the rated voltage of each load corresponding to the power supply transformer to obtain N current voltages and N rated voltages of the loads;
[0135] determine the target gear of the thyristor bridge circuit corresponding to each power supply transformer according to the N current voltages and the N rated voltages of the loads.
[0136] In this embodiment, the first controller can quickly and accurately determine the target gear of the thyristor bridge circuit 20 corresponding to each power supply transformer 30 through the N current voltages and the N rated voltages of the loads.
[0137] Exemplarily, N=3, the 3 load rated voltages can be an A-phase load rated voltage, a B-phase load rated voltage and a C-phase load rated voltage. The load rated voltage can be set according to actual conditions, which is not limited herein, for example, can be 220V or 380V, etc.
[0138] It should be noted that the N load rated voltages can be the same or different, which is not limited herein.
[0139] Exemplarily, the first controller can pre-store the N load rated voltages for subsequent direct calling. Alternatively, the technical data related to the load 50 can be consulted to obtain the load rated voltage of the load.
[0140] In some examples, the first controller is specifically used for:
[0141] For each power supply transformer, the following steps are performed to determine the target gear of the thyristor bridge circuit corresponding to each power supply transformer:
[0142] The difference between the load rated voltage corresponding to the power supply transformer and the current voltage of the load corresponding to the power supply transformer is determined as the first voltage difference;
[0143] The ratio of the first voltage difference to the current voltage of the load corresponding to the power supply transformer is taken as the first voltage ratio;
[0144] The gear corresponding to the first voltage ratio is determined as the target gear.
[0145] In the embodiment, the first controller can further quickly and accurately determine the target gear according to the above steps.
[0146] Exemplarily, each gear in the n*(n-1)+1 gears one-to-one corresponds to a compensation range, the compensation range in which the first voltage ratio is located is determined as the target compensation range, and the gear corresponding to the target compensation range is determined as the target gear.
[0147] Exemplarily, taking the A-phase power supply transformer T 1a as an example, the current voltage of the load corresponding to the A-phase power supply transformer T 1a is a1, and the load rated voltage corresponding to the A-phase power supply transformer T 1a is a2, then the first voltage difference is a2-a1, and the first voltage ratio is (a2-a1) / a1. If the first voltage ratio is within the compensation range corresponding to the first gear, the first gear is determined as the target gear. The implementation processes of the B-phase power supply transformer T 1b and the C-phase power supply transformer T 1c are the same, which will not be repeated herein.
[0148] It should be noted that if a2-a1 is positive, it means that the load current voltage is lower than the load rated voltage, at this time, the forward gear should be selected, for example, +5% gear; if a2-a1 is negative, it means that the load current voltage is higher than the load rated voltage, at this time, the reverse gear should be selected, for example, -5% gear.
[0149] In some embodiments, the voltage compensator further comprises:
[0150] The third controller is connected to each of the power extraction transformers respectively, and is configured to control each of the power extraction transformers to obtain power from the power grid connected to the corresponding power supply line when it is monitored that the load current voltage of the load is less than the preset voltage and the bridge arm current on each of the thyristor bridge circuits is completely zero-crossed.
[0151] Exemplarily, as shown in Figure 1 and Figure 2 , the control A-phase power extraction transformer T 1a obtains power from the power grid connected to the A-phase power supply line, and / or, the control B-phase power extraction transformer T 1b obtains power from the power grid connected to the B-phase power supply line, and / or, the control C-phase power extraction transformer T 1c obtains power from the power grid connected to the C-phase power supply line.
[0152] In some embodiments, the control each of the power extraction transformers 30 to obtain power from the power grid connected to the corresponding power supply line specifically comprises:
[0153] The control each of the power extraction transformers 30 to obtain power from the power grid connected to the corresponding power supply line when it is monitored that the load current voltage of the load 50 is less than the preset voltage and the bridge arm current on each of the thyristor bridge circuits 20 is completely zero-crossed.
[0154] In the embodiment, the third controller controls each of the power extraction transformers 30 to obtain power from the power grid connected to the corresponding power supply line when it is monitored that the load current voltage of the load 50 is less than the preset voltage and the bridge arm current on each of the thyristor bridge circuits 20 is completely zero-crossed, which can improve the safety of the voltage compensator.
[0155] For example, the A-phase power supply line connected to load 50 is connected to an A-phase voltage transformer, the B-phase power supply line connected to load 50 is connected to a B-phase voltage transformer, and the C-phase power supply line connected to load 50 is connected to a C-phase voltage transformer. The third controller is connected to the A-phase voltage transformer, the B-phase voltage transformer, and the C-phase voltage transformer, respectively. The current load voltage of load 50 may include at least one of the A-phase load voltage, the B-phase load voltage, and the C-phase load voltage. The A-phase load voltage can be monitored via the A-phase voltage transformer, the B-phase load voltage can be monitored via the B-phase voltage transformer, and the C-phase load voltage can be monitored via the C-phase voltage transformer.
[0156] For example, the preset voltage may include at least one of phase A preset voltage, phase B preset voltage, and phase C preset voltage. Detecting that the current load voltage of load 50 is less than the preset voltage includes: detecting that the current load voltage of phase A of load 50 is less than the phase A preset voltage, and / or, detecting that the current load voltage of phase B of load 50 is less than the phase B preset voltage, and / or, detecting that the current load voltage of phase C of load 50 is less than the phase C preset voltage. For example, if the preset voltage may include phase A preset voltage, phase B preset voltage, and phase C preset voltage, then detecting that the current load voltage of load 50 is less than the preset voltage includes: detecting that the current load voltage of phase A of load 50 is less than the phase A preset voltage, detecting that the current load voltage of phase B of load 50 is less than the phase B preset voltage, and detecting that the current load voltage of phase C of load 50 is less than the phase C preset voltage. As another example, if the preset voltage includes the phase A preset voltage, then detecting that the current load voltage of load 50 is less than the preset voltage includes: detecting that the current load voltage of phase A of load 50 is less than the phase A preset voltage.
[0157] It should be noted that the preset voltages for phase A, phase B, and phase C can all be set according to actual conditions, and are not limited here. Furthermore, at least two of the preset voltages for phase A, phase B, and phase C can be equal, or all can be unequal.
[0158] For example, such as Figure 1 As shown, the A-phase power extraction transformer T 1a Connect the current transformer for phase A and the energy extraction transformer T for phase B. 1b Connect the B-phase current transformer and the C-phase power extraction transformer T. 1c Connect the C-phase current transformer. The third controller is connected to the A-phase, B-phase, and C-phase current transformers respectively. The bridge arm current on each thyristor bridge circuit 20 may include at least one of the A-phase bridge arm current, B-phase bridge arm current, and C-phase bridge arm current. The A-phase bridge arm current CTI can be monitored through the A-phase current transformer. a The B-phase bridge arm current CTI can be monitored via the B-phase current transformer. band the C-phase bridge arm current CTI c .
[0159] Exemplarily, the bridge arm currents on each thyristor bridge circuit 20 all completely zero-crossing includes: the A-phase bridge arm current CTI a on each thyristor bridge circuit 20 completely zero-crossing, and / or the B-phase bridge arm current CTI b on each thyristor bridge circuit 20 completely zero-crossing, and / or the C-phase bridge arm current CTI c on each thyristor bridge circuit 20 completely zero-crossing. For example, if the bridge arm currents on each thyristor bridge circuit 20 include the A-phase bridge arm current CTI a , the B-phase bridge arm current CTI b , and the C-phase bridge arm current CTI c , then the bridge arm currents on each thyristor bridge circuit 20 all completely zero-crossing includes: the A-phase bridge arm current CTI a on each thyristor bridge circuit 20 completely zero-crossing, the B-phase bridge arm current CTI b on each thyristor bridge circuit 20 completely zero-crossing, and the C-phase bridge arm current CTI c on each thyristor bridge circuit 20 completely zero-crossing. For another example, if the bridge arm currents on each thyristor bridge circuit 20 include the A-phase bridge arm current CTI a , then the bridge arm currents on each thyristor bridge circuit 20 all completely zero-crossing includes: the A-phase bridge arm current CTI a on each thyristor bridge circuit 20 completely zero-crossing.
[0160] That is to say, in the embodiments of the present application, the bridge arm currents on each thyristor bridge circuit 20 are monitored by the current transformers, the pilot protection module 10 is turned on during the gear shifting process, and then the zero-crossing detection is performed on the bridge arm currents monitored by the current transformers, and the other gear (i.e. the target gear) is turned on after the complete zero-crossing.
[0161] In some embodiments, the first controller is multiplexed as the third controller, i.e. the first controller and the third controller are the same controller.
[0162] In some other embodiments, the first controller, the second controller and the third controller are the same controller.
[0163] Exemplarily, the first controller to the third controller all adopt the digital signal processing (DSP) chip which is mature and common in the prior art to do real-time control, and the peripheral circuit mainly includes the functions of data acquisition and device communication, device protection, etc. For example, the model of the first controller to the third controller can be DSP28335.
[0164] It can be understood that, as Figure 2As shown, the thyristor group S0 is turned on according to the direction of the induced short-circuit current, and the AC one-cycle waveform is sinusoidal, the upper half cycle left thyristor is turned on, and the lower half cycle right thyristor is turned on.
[0165] It should be noted that, Figure 2 U in load represents the load voltage, I load represents the load current, and the arrow represents the flow direction of the load current.
[0166] In order to better understand the voltage compensator and the control method thereof provided by the embodiments of the present application, a specific embodiment will be described below.
[0167] The embodiments of the present application provide a thyristor-based transformer series-parallel dynamic voltage compensator (i.e., a voltage compensator), which mainly comprises a thyristor bridge circuit and a bypass gear transition circuit (i.e., a protection module), a control system (i.e., a controller), a parallel energy-taking transformer (i.e., an energy-taking transformer), and a series compensation transformer (i.e., a compensation transformer).
[0168] The thyristor bridge circuit is composed of multiple pairs of single anti-parallel thyristors, and one end of the upper and lower bridge arms is connected to the two ends of the primary side of the series compensation transformer, and the other end is connected to the tap of the secondary side of the parallel energy-taking transformer and the two end leads (i.e., the first tap to the nth tap). Different thyristors are turned on to realize the switching of different transformer gears.
[0169] The bypass gear transition circuit is composed of a current-limiting reactor and a group of single anti-parallel thyristors, which can be used as a device bypass, and is turned on during gear switching to prevent the transformer secondary side tap short circuit caused by the simultaneous conduction of the upper and lower bridge arms of the thyristor at a certain moment from damaging the device.
[0170] The control system uses a digital signal processing (DSP) chip for real-time control, and the peripheral circuit mainly includes data acquisition and device communication, device protection, and other functions.
[0171] The parallel energy-taking transformer has an adjustable primary side winding, mainly compatible with low-voltage power distribution and other application scenarios, and a multi-tap secondary side designed according to the number of required gears.
[0172] The series compensation transformer uses an isolation transformer, and the primary side is connected to the thyristor group, and the secondary side is connected in series to the main power supply line (i.e., the power supply line).
[0173] The embodiment of the present application provides a dynamic voltage compensator based on thyristor control, which mainly comprises a 4-tap energy transformer, a series-connected transformer (i.e. a compensation transformer), a thyristor switching unit (i.e. a thyristor bridge circuit) using 8 pairs of one-way anti-parallel thyristors, a bypass current-limiting reactor (i.e. a current-limiting reactor) and a control system (i.e. a first controller to a third controller). When the load-side monitoring voltage is too low, the multi-tap energy transformer takes energy from the power grid, the thyristor control transformer tap output compensates the load voltage to the compensation voltage near the required amplitude of the rated voltage, and the series-connected transformer is superimposed on the system power source on the line, so that the load-side voltage remains stable and the safe operation of the load side is ensured.
[0174] The switching control (i.e. a voltage compensator control method) of the dynamic voltage compensator based on the thyristor control transformer series-parallel connection of the embodiment of the present application is as follows: the load voltage value is detected by using a voltage transformer and the thyristor bridge arm current is monitored by using a current transformer, and the monitoring values are sent to the control system. When the load voltage (i.e. the current load voltage) is in the rated range, the device bypass thyristor (i.e. the thyristor) control starts the device bypass (i.e. the protection module), and the thyristor gear control signal is locked. When the detected load-side voltage (i.e. the current load voltage) rises or falls beyond the rated range, the control system (i.e. the first controller to the third controller) automatically selects the appropriate switching gear according to the difference between the current load voltage value and the set rated value (i.e. the load rated voltage), turns on the control thyristor of the corresponding gear, and turns off the bypass thyristor.
[0175] As shown in the circuit shown in Figure 1 , it is a single-phase compensation gear topology example diagram, 10%, 25% and 30% are tapped from the secondary side of the parallel energy transformer, 8 pairs of one-way anti-parallel thyristors are used to control 13 gears in both directions for compensation, and each 5% sets a gear. The compensation range is ±30%, and the corresponding on thyristor setting of the gear is shown in Table 1.
[0176] The system simulation of single-phase voltage compensation is carried out by using the circuit topology shown in Figure 1 . The system voltage Us is 3300V, the simulated line impedance voltage drop is about 300V, the device (i.e. the voltage compensator) is put into operation for voltage compensation, and the control strategy is 0 gear control at the initial time and 30% gear control (S1, S8 thyristor conduction) at 0.02s. The load-side voltage rises. The thyristor group trigger signal is shown in Figure 3 , Figure 4 , Figure 5 . It can be seen that the load voltage UI is lower than the system voltage before 0.2s, and the device is put into use after 0.2s. The load voltage changes with the device switching, as shown in Figure 6 . The load voltage changes with the device switching, as shown in Figure 6It can be seen that the transformer series-parallel dynamic voltage compensator based on thyristor provided by the embodiment of the application can effectively compensate the load-side voltage, the control process has good precision, the voltage difference of switching gears is small, and the impact on the main circuit is effectively reduced. In the transformer series-parallel dynamic voltage compensator based on thyristor provided by the embodiment of the application, Figures 3 to 6 In the figure, the abscissa represents time t, and the unit is s (second); the ordinate is voltage, and the unit is V (volt); Figure 6 In the figure, U s represents the system voltage, U l represents the load voltage.
[0177] The embodiment of the application provides a transformer series-parallel dynamic voltage compensator based on thyristor, which is used for power quality management. The transformer series-parallel dynamic voltage compensator based on thyristor mainly comprises a thyristor group, a control system, a parallel power-taking transformer and a series compensation transformer. The thyristor group is composed of a bridge-type thyristor gear control circuit and a bypass gear shifting transition circuit. The primary side winding of the parallel power-taking transformer is adjustably connected in parallel to a load-side power supply line, and the secondary side tap and both end leads are respectively connected to the bridge-type thyristor group. The primary side of the series compensation transformer is connected to two bridge arms of the thyristor group, and the secondary side is connected in series into a power supply line. The embodiment of the application is used for monitoring the load-side voltage and obtaining electric energy, and then outputs different sizes of voltage to the main power supply line through the series compensation transformer. The power quality can be effectively improved by effectively solving the voltage fluctuation of the power distribution network and realizing the self-regulation of the power distribution network voltage.
[0178] The embodiment of the application at least has the following beneficial effects:
[0179] 1. The bridge-type circuit of the thyristor is used to realize bidirectional compensation capability, and the maximum number of control gears can be obtained by switching with the least number of thyristor groups and transformer tap combinations. The box connection is more simple, the design cost is effectively reduced, and the insulation design is more easily realized.
[0180] 2. The primary side of the series compensation transformer is connected in parallel to a double-ended double-directional thyristor and a current-limiting reactor, which effectively avoids the short circuit problem of the secondary side tap of the parallel power-taking transformer caused by the gear shifting process.
[0181] 3. The primary side winding of the parallel power-taking transformer can be adjusted through different taps, which is compatible with medium and low voltage occasions and improves the voltage application range of the device.
[0182] Embodiment 2
[0183] The power supply system provided by the embodiment of the application can be applied to the process in which the power supply system supplies power to the load.
[0184] As shown in Figure 1 and Figure 2 , the power supply system provided by the embodiment of the application can comprise:
[0185] a load 50;
[0186] a power supply line connected with the load 50, for supplying power to the load 50;
[0187] a voltage compensator as any one of the embodiments 1, connected with the power supply line, for compensating the load current voltage of the load 50, to control the voltage of the load 50 within the preset range.
[0188] The power supply system provided by the embodiments of the present application comprises the voltage compensator of the embodiment 1 of the present application, that is, has the beneficial effects and implementation manners of the voltage compensator provided by the embodiment 1 of the present application, and the specific description of the power supply system can be referred to the specific description of the power supply system in the above-mentioned embodiment 1, which will not be described here again.
[0189] It can be understood that the above implementation manners are only exemplary implementation manners adopted for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also considered as the protection scope of the present application.
Claims
1. A voltage compensator, characterized by, The voltage compensator comprises N power take-off transformers (30), N thyristor bridge circuits (20), N compensation transformers (40) and a first controller, the power take-off transformers (30), the thyristor bridge circuits (20) and the compensation transformers (40) correspond to each other respectively, and N is a positive integer; Each of the power take-off transformers (30) is adjustably connected to a power supply line of a corresponding load (50) at a primary side winding thereof, and is connected to a corresponding thyristor bridge circuit (20) at a secondary side tap thereof, is used to obtain electric energy from a power grid connected to the power supply line, and is used to convert the electric energy into a target compensation voltage when the corresponding thyristor bridge circuit (20) is at a target gear position; wherein the number of the secondary side taps of each of the power take-off transformers (30) is n, n is a positive integer, the target compensation voltage is a compensation voltage corresponding to the target gear position, and the target gear position is a compensation gear position corresponding to a current voltage of the load. The first controller is connected to each of the thyristor bridge circuits (20) and is used to control each of the thyristor bridge circuits (20) to be at the target gear position. Each of the thyristor bridge circuits (20) is connected to a primary side of a corresponding compensation transformer (40). Each of the compensation transformers (40) is connected to a power supply line at a secondary side thereof. The thyristor bridge circuit (20) and the compensation transformer (40) corresponding to each of the thyristor bridge circuits (20) are used to transmit the target compensation voltage to compensate for a current voltage of the load (50), so as to control the voltage of the load (50) to be within a preset range.
2. The voltage compensator of claim 1, wherein, Each of the thyristor bridge circuits (20) comprises a first thyristor unit to an nth thyristor unit; the first thyristor unit comprises a first thyristor group and an (n+1)th thyristor group, the second thyristor unit comprises a second thyristor group and an (n+2)th thyristor group, and the nth thyristor unit comprises an nth thyristor group and a 2nth thyristor group. The primary side winding of each of the power take-off transformers (30) comprises a first tap to an nth tap, and the secondary side winding of each of the power take-off transformers (30) comprises an (n+1)th tap to an mth tap; wherein m is a positive integer greater than n. The first end and the second end of each of the first thyristor unit to the nth thyristor unit are connected in series with the primary side of the corresponding compensation transformer (40). The third end of each ith thyristor unit is connected to the corresponding ith tap, i is an integer greater than or equal to 1 and less than or equal to n. Each of the mth taps is grounded, and one of the (n+1)th tap to the (m-1)th tap is adjustably connected to the power supply line of the load (50) connected to the power take-off transformer (30).
3. The voltage compensator of claim 2, wherein, Each of the first thyristor group to the 2nth thyristor group comprises two thyristors in a unidirectional anti-parallel connection.
4. The voltage compensator of claim 3, wherein, The voltage compensator further comprises: At least one protection module (10), each of the protection modules (10) is connected in parallel between the primary side of the corresponding compensation transformer (40) and the corresponding thyristor bridge circuit (20). The second controller is connected with the at least one protection module (10) and is configured to control the on or off of each protection module (10) to prevent the short circuit of the secondary side gear tap of the energy-taking transformer (30) corresponding to the protection module (10) during the switching process of the corresponding thyristor bridge circuit (20).
5. The voltage compensator of claim 4, wherein, The second controller is specifically configured to: In the case of the target gear corresponding to each energy-taking transformer (30), control the on of the protection module (10) corresponding to each energy-taking transformer (30), or control the off of each protection module (10); The first controller is specifically configured to: In the case of the target gear corresponding to each energy-taking transformer (30), control the off of the first to the n-th thyristor groups, or control the on of one of the first to the n-th thyristor groups corresponding to each energy-taking transformer (30), control the on of one of the n+1-th to the 2n-th thyristor groups corresponding to each energy-taking transformer (30), and control the off of the remaining thyristor groups.
6. The voltage compensator of claim 5, wherein, n＝4； The second controller is specifically configured to: In the case of the target gear being the zeroth gear, control the on of the protection module (10) corresponding to each energy-taking transformer (30); In the case of the target gear being the first to the twelfth gears, control the off of the protection module (10) corresponding to each energy-taking transformer (30); The first controller is specifically configured to: In the case of the target gear being the zeroth gear, control the off of the first to the eighth thyristor groups (S1-S8) corresponding to each energy-taking transformer (30); In the case of the target gear being the first gear, control the on of the third and the eighth thyristor groups (S3, S8) corresponding to each energy-taking transformer (30), and control the off of the remaining thyristor groups; In the case of the target gear being the second gear, control the on of the first and the sixth thyristor groups (S1, S6) corresponding to each energy-taking transformer (30), and control the off of the remaining thyristor groups; In the case of the target gear being the third gear, control the on of the second and the seventh thyristor groups (S2, S7) corresponding to each energy-taking transformer (30), and control the off of the remaining thyristor groups; In the case of the target gear being the fourth gear, control the on of the second and the eighth thyristor groups (S2, S8) corresponding to each energy-taking transformer (30), and control the off of the remaining thyristor groups; In the case of the target gear being the fifth gear, control the on of the first and the seventh thyristor groups (S1, S7) corresponding to each energy-taking transformer (30), and control the off of the remaining thyristor groups; In the case of the target gear being the sixth gear, control the on of the first and the eighth thyristor groups (S1, S8) corresponding to each energy-taking transformer (30), and control the off of the remaining thyristor groups; In the case that the target gear is the seventh gear, the fourth thyristor group (S4) and the seventh thyristor group (S7) corresponding to each energy extraction transformer (30) are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off. In the case that the target gear is the eighth gear, the second thyristor group (S2) and the fifth thyristor group (S5) corresponding to each energy extraction transformer (30) are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off. In the case that the target gear is the ninth gear, the third thyristor group (S3) and the sixth thyristor group (S6) corresponding to each energy extraction transformer (30) are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off. In the case that the target gear is the tenth gear, the fourth thyristor group (S4) and the sixth thyristor group (S6) corresponding to each energy extraction transformer (30) are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off. In the case that the target gear is the eleventh gear, the third thyristor group (S3) and the fifth thyristor group (S5) corresponding to each energy extraction transformer (30) are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off. In the case that the target gear is the twelfth gear, the fourth thyristor group (S4) and the fifth thyristor group (S5) corresponding to each energy extraction transformer (30) are controlled to be turned on, and the rest of the thyristor groups are controlled to be turned off.
7. The voltage compensator of claim 4, wherein, Each protection module (10) comprises a current limiting reactor (L) and a group of alpha thyristors (S0) connected in series between two ends of a primary side of a corresponding compensation transformer (40), and the group of alpha thyristors (S0) is connected to the second controller.
8. The voltage compensator of claim 7, wherein, The group of alpha thyristors (S0) comprises two thyristors connected in anti-parallel unidirectionally.
9. The voltage compensator of claim 1, wherein, Each compensation transformer (40) comprises an isolation transformer.
10. The voltage compensator of claim 1, wherein, The voltage compensator further comprises: a third controller connected to each energy extraction transformer (30) for controlling each energy extraction transformer (30) to obtain electric energy from a power grid connected to a corresponding power supply line when it is monitored that a current load voltage of a load (50) is less than a preset voltage and that all bridge arm currents of each thyristor bridge circuit (20) are completely zero-crossed.
11. The voltage compensator of claim 10, wherein, The first controller is multiplexed as the third controller.
12. A power supply system characterized by comprising: comprises: a load (50); a power supply line connected to the load (50) for supplying power to the load (50); The voltage compensator of any one of claims 1 to 11, connected to the power supply line, is used for compensating a current load voltage of the load (50) to control the voltage of the load (50) to be within a preset range.