A current balancing device for power supply side

Abstract

The utility model discloses a current balancing device for a power supply side, the device is used for evenly distributing the current of a single-phase load to a three-phase circuit, the device comprises an iron core body, a plurality of primary coils are sleeved on the iron core body, and two adjacent primary coils are connected in star shape; the primary coils are used for connecting the circuit on the power supply side; a plurality of secondary coils are sleeved on the iron core body, and two adjacent secondary coils are connected in series, and the secondary coils are used for connecting the output side circuit, so as to improve the problem that a traditional three-phase balancer is adjusted and balanced by a main controller, is composed of a large number of electronic components, has a small working current, and cannot realize the adjustment of large current due to device limitations.

Description

Technical Field

[0001] The utility model relates to three-phase unbalance management, in particular to a current balancing device used for a power supply side. Background Art

[0002] With the development of technology, three-phase imbalance is an important indicator of power quality. Three-phase imbalance is often caused by asymmetric three-phase components, line parameters or loads. Considering the uncertainty of the current three-phase load factors, the three-phase voltage and current at the power supply point are prone to imbalance, resulting in loss lines and even potential hazards to the normal operation of the motor at the power supply point. When the three-phase imbalance exceeds the range that the distribution network can bear, the safe operation of its power cannot be guaranteed, so manual three-phase balance adjustment is required.

[0003] The common control method is to adjust the load to achieve three-phase power balance. However, due to the diversity of load usage, adjusting the load may limit the timeliness of the adjustment, making the overall controllability not ideal. Based on this, at present, automatic load adjustment devices can be set up on important power supply paths at the technical level, and the three-phase loads can be balanced by performing on-load phase switching scheduling on single-phase loads. However, this automatic load adjustment device requires the cooperation of the main controller and the phase converter. There are a large number of electronic components in the automatic load adjustment device itself. On the one hand, during the long-term use of the automatic load adjustment device, the electronic components are easily affected by factors such as temperature and humidity, resulting in reduced reliability or damage. On the other hand, due to the power limitations of the main controller and the phase converter, the automatic load adjustment device is not ideal for the control of high-power and high-current equipment. Therefore, it is worth studying how to use simpler devices on the power supply side to balance the current and reduce circuit risks. Utility Model Content

[0004] The purpose of the utility model is to provide a current balancing device for the power supply side, in order to improve the problem that the traditional three-phase balancer is adjusted and balanced by a main controller, is composed of many electronic components, has a small working current, and cannot achieve large current regulation due to device limitations.

[0005] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0006] A current balancing device for a power supply side, the device is used to evenly distribute the current of a single-phase load to a three-phase circuit, the device comprises an iron core body, a plurality of primary coils are sleeved on the iron core body, and two adjacent primary coils are connected in a star shape; the primary coils are used to connect the circuit on the power supply side; a plurality of secondary coils are sleeved on the iron core body, and two adjacent secondary coils are connected in series, and the secondary coils are used to connect the circuit on the output side.

[0007] The technical concept is: the device uses a high magnetic permeability core body to provide a low-loss magnetic flux path, and multiple primary coils set on the core body are connected in a star shape between adjacent two. One end of all primary coils is connected to a common node, and the other end is connected to the three-phase power supply system, so that the current can be evenly distributed to the three phases after being input from the single-phase load, thereby achieving three-phase balance.

[0008] Preferably, there are three primary coils, and each primary coil has the same number of turns; the number of secondary coils corresponds to the number of primary coils, and each secondary coil has the same number of turns.

[0009] A further technical solution is that the secondary coil includes an input end and an output end, and the three secondary coils are coil L1, coil L2 and coil L3, the output end of coil L1 is connected to the input end of coil L2, and the output end of coil L2 is connected to the output end of coil L3.

[0010] A further technical solution is that when the primary coil is connected in star shape, the input side of the primary coil should be connected to the three phases of the three-phase power supply respectively, and the output side of the primary coil is usually connected to a common neutral point.

[0011] Preferably, the core body comprises a lower core and an upper core, the upper core is detachably connected to the lower core, the upper core and the lower core are both E-shaped, and the primary coil and the secondary coil are both wound on the lower core.

[0012] Preferably, the primary coil and the secondary coil are arranged opposite to each other on the lower iron core, and electromagnetic induction is generated by the primary coil and the secondary coil on the lower iron core.

[0013] A further technical solution is that the winding directions of the primary coil and the secondary coil are opposite.

[0014] A further technical solution is that an isolation distance is provided between the primary coil and the secondary coil, and an insulating material is filled between the isolation distance.

[0015] Compared with the prior art, the beneficial effects of the utility model are at least one of the following:

[0016] The utility model realizes the balance of current in the three-phase circuit through the electromagnetic induction relationship between the primary coil and the secondary coil, the connection mode of the coil and the structural design of the iron core. This helps to reduce the unbalanced load of the power grid and improve the utilization efficiency of electric energy. The utility model uses the primary coil to be connected to the three-phase power supply in a star shape, and each coil undertakes a part of the distribution task of the single-phase current.

[0017] The utility model also designs three secondary coils to be connected in series, and through the reverse connection of specific coil ends, it is ensured that the secondary coil can maintain current balance under the influence of three different phase voltages, so that the current of the single-phase load is evenly distributed to the three-phase circuit through this device, so that the load of the distribution system achieves the purpose of three-phase balance.

[0018] The device of the utility model can distribute the current to the other two phases through the device when the load is on any phase, so that the current on the three phase lines tends to be balanced. This is beneficial to reduce power loss, reduce the pressure on the power grid, and improve the stability of the power grid. At the same time, the device of the utility model adopts a simple physical structure, deliberately avoids the participation of electronic components, has high reliability, and is not limited by high-power and high-current devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the utility model.

[0020] Figure 2 This is the single-phase principle diagram of the utility model.

[0021] Figure 3 This is the three-phase principle diagram of the utility model. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0023] The existing three-phase voltage imbalance refers to the unevenness of the amplitude or phase of the three-phase voltage in the power system. Imbalance will affect the normal operation of electrical equipment, increase energy loss, and reduce the quality of power. Under normal operation of the common connection point of the existing power system, the allowable value of voltage imbalance is 2%, which means that the deviation between the three-phase voltages should be kept within 2% of the rated value. Based on reliability considerations, the limit value of imbalance is allowed to be 4% in a short time. If it exceeds this range, it may have a greater impact on system stability and electrical equipment. At present, a three-phase balancer is traditionally used to adjust the problem of three-phase voltage imbalance. The equipment adjusts the load of each phase through the main controller to keep the voltage as balanced as possible. However, such main controllers are usually composed of electronic components, and traditional balancers may not be able to handle large currents, which limits their use in large or high-load applications. Secondly, electronic components are prone to failure in harsh industrial environments, especially in environments with high loads, high temperatures, high humidity, or corrosive substances.

[0024] refer to Figure 1As shown, one embodiment of the utility model is a current balancing device for the power supply side, the device is used to evenly distribute the current of a single-phase load to a three-phase circuit, the device includes an iron core body 1, wherein the iron core body 1 needs to have a high magnetic permeability, so the material of the iron core body 1 can be existing silicon steel, wherein the iron core body 1 has a certain geometric shape, which can be an E-type or other shapes suitable for winding and transmitting magnetic flux.

[0025] A plurality of primary coils 2 are sleeved on the core body 1, and two adjacent primary coils 2 are connected in star shape; that is, two adjacent primary coils 2 are connected in star shape, such as Y-shaped connection. One end of all primary coils is connected to a common node, and the primary coil 2 is used to connect the circuit on the power supply side; the primary coil 2 is connected to the power supply side circuit, and the function of the primary coil 2 is to receive the current of the power grid. Since the primary coil 2 is connected in star shape, the primary coil 2 can have a common neutral point, so that the voltage or current of a single phase can be transmitted to the three coils in three ways.

[0026] A plurality of secondary coils 3 are sleeved on the core body 1. Since the primary coil 2 is connected to the power supply side circuit, it is used to receive current from the power grid. The secondary coil 3 outputs balanced current to the load, and two adjacent secondary coils 3 are connected in series. The secondary coil 3 is used to connect the output side circuit. On one side of the core body 1, a plurality of secondary coils 3 are connected in series. The secondary coils 3 connected in series can ensure the consistency of current between them, that is, when the load current passes through the secondary coils 3, the same current will flow through all the secondary coils 3. The device distributes the current evenly to the three primary coils through electromagnetic coupling, and then these primary coils are coupled to the secondary coil 2 through the magnetic flux of the core, thereby ensuring the balance of the three-phase current of the output side circuit.

[0027] For reference, in terms of operating principle, when an unbalanced current enters the primary coil 2, the core body 1 will induce corresponding voltage and current on the secondary coil 3 of each phase according to the principle of electromagnetic induction. Since the secondary coil 3 is connected in series, it can ensure that the three-phase current of the output side circuit is balanced and consistent. As a result, the balance device can not only balance the load, but also reduce power loss, and is conducive to improving power quality and power supply stability.

[0028] refer to Figure 2 As shown, based on the above embodiment, another embodiment of the utility model is that there are three primary coils 2, and the number of turns of each primary coil 2 is the same, the number of secondary coils 3 corresponds to the primary coil 2, and the number of turns of each secondary coil 3 is the same.

[0029] The same number of turns of the primary coil 2 and the same number of turns of the secondary coil 3 are both to ensure that the voltage conversion ratio of each phase is consistent. At the same time, in systems with different load characteristics, the current and voltage on the output side can be optimized by adjusting the turns ratio to achieve a more efficient and stable power supply effect. By changing the turns ratio, the output characteristics can be automatically adjusted, which can be adaptively adjusted for applications with large load or input power fluctuations.

[0030] For example, when the number of turns of the primary coil 2 and the secondary coil 3 are the same, it means that the transformation ratio of the primary coil 2 and the secondary coil 3 is 1:1, which means that ideally, if the input voltage of the primary coil remains consistent, the output voltage of the secondary coil will also remain consistent, thereby maintaining the voltage balance between the phases.

[0031] For example, all primary coils 2 use a fixed number of turns, and all secondary coils 3 use another fixed number of turns, so that the transformation ratio of the primary coil 2 and the secondary coil 3 is fixed. On the one hand, it can work at a specific transformation ratio and set the ratio of boost or buck according to specific needs. This ensures that the output voltage meets the requirements of the load device; on the other hand, if the transformation ratio of the secondary coil 3 is consistent between different phases, even if the load changes slightly, the voltage or current output by each secondary coil 3 will be the same, which helps to maintain the three-phase balance of the system.

[0032] Furthermore, the secondary coil 3 includes an input end and an output end, and the three secondary coils 3 are coil L1, coil L2 and coil L3, the output end of coil L1 is connected to the input end of coil L2, and the output end of coil L2 is connected to the output end of coil L3. Since the three secondary coils are arranged in series, it means that the current carried by all secondary coils will be the same;

[0033] For reference, the current flowing through the primary coils LA, LB, and LC is I1. By setting the turns ratio of the primary coil and the secondary coil 3, the current can be adjusted, and then the current of the single-phase load is evenly distributed to the three-phase circuit through this device, so that the load of the distribution system can achieve the purpose of three-phase balance.

[0034] Exemplarily, the corresponding relationship between the current of the primary coil and the current of the secondary coil is:

[0035]

[0036] Where I1 is the current of the primary coil; I2 is the current of the secondary coil; N1 is the number of turns of LA; and N2 is the number of turns of L1. The current ratio of the primary coil 2 to the secondary coil 3 is determined by the ratio of their turns.

[0037] For reference, after the three secondary coils 3 are connected in series, the series connection ensures that the current passing through each secondary coil is equal. Since the three secondary coils 3 are respectively equivalent to one phase in the three-phase system, the current of the corresponding phase can be distributed through the three secondary coils 3, thereby achieving the purpose of balanced power supply.

[0038] For further reference, Figure 2 and Figure 3 As shown, when the primary coil 2 is connected in star shape, the input side of the primary coil 2 should be connected to the three phases of the three-phase power supply respectively, and the output side of the primary coil 2 is usually connected to a common neutral point.

[0039] Among them, the primary coils are LA, LB and LC, and the primary coils are connected to each other through star connection, and one end of all the primary coils is connected to a common neutral point, and the other end is connected to the three phases of the three-phase power supply. Among them, the secondary coils are L1, L2 and L3, and the secondary coils are connected in series, wherein one end of L1 is connected to the opposite end of L2, and the other end of L2 is connected to the same end of L3.

[0040] During operation, when the load current is I2, since the L1, L2 and L3 coils are connected in series, the current flowing through L1, L2 and L3 is I2. Assuming that the voltage across the secondary coil L1 is U1, the voltage across the secondary coil L2 is U2, and the voltage across the secondary coil L3 is U3, the output voltage U0 is based on the combination of the three voltages U1, U2 and U3, and its output voltage U0=U1+U2-U3. The determination of its output voltage U0 depends on the addition and subtraction of the voltage values ​​of the three secondary coils. Its output U0 is the result of the vector superposition of the voltages of the three secondary coils.

[0041] Therefore, the electromotive force of the primary coil 2 and the secondary coil 3 is proportional to their number of turns, that is, the voltage ratio is equal to the turns ratio, and the current ratio is inversely proportional to the turns ratio. The device can achieve an even distribution of the single-phase load current in the three-phase circuit by appropriately setting the turns ratio of the primary coil and the secondary coil, thereby achieving the effect of three-phase load balancing in the distribution system.

[0042] Based on the above embodiments, another embodiment of the utility model is that the above-mentioned core body 1 includes a lower core 101 and an upper core 102, and the above-mentioned upper core 102 is detachably connected to the lower core 101, wherein the core body 1 is designed in a manner that the lower core 101 and the upper core 102 can be disassembled from each other, which is conducive to manufacturing, assembly and maintenance.

[0043] The upper core 102 and the lower core 101 are both in an E shape, wherein the E shape is composed of a vertical line in the middle and two vertical lines on both sides, so that the primary coil 2 and the secondary coil 3 can be easily wound on the lower core 101, and it also helps to close the magnetic flux in the core; the primary coil 2 and the secondary coil 3 are both wound on the lower core 101. The design of the detachable connection between the lower core 101 and the upper core 102 makes the winding and installation of the primary coil 2 and the secondary coil 3 easier. When the core body 1 needs to be repaired or the coil is replaced, the upper core 102 can be disassembled to optimize the maintenance process. In addition, during the assembly process, the device can also be wound on the lower core 101 first, and then the upper core 102 can be assembled after the winding is completed. This is beneficial for shortening the wire ends and reducing the loss of wire materials in the winding process.

[0044] Based on the above embodiment, another embodiment of the utility model is that the above primary coil 2 and secondary coil 3 are relatively arranged on the lower iron core 101, and the primary coil and secondary coil are relatively arranged on the same iron core segment. Such an arrangement is more conducive to the coupling of magnetic flux between the coils, thereby improving the electromagnetic induction efficiency, and the primary coil 2 and the secondary coil 3 are electromagnetically induced on the lower iron core 101. Among them, the primary coil 2 and the secondary coil 3 are both installed in an E shape, which can form a better magnetic circuit closed path, thereby ensuring a stable working magnetic circuit and reducing magnetic loss.

[0045] Furthermore, the winding directions of the primary coil 2 and the secondary coil 3 are opposite. On the one hand, magnetic leakage can be reduced. Specifically, magnetic leakage is a magnetic flux phenomenon that does not pass through the secondary coil 3. Magnetic leakage may cause work efficiency problems. By having the primary coil 2 and the secondary coil 3 in opposite winding directions, they can offset some of the magnetic fields to a certain extent and reduce the influence of magnetic leakage. On the other hand, the opposite winding directions of the primary coil 2 and the secondary coil 3 are conducive to setting the phase difference, so that the voltage induced in the secondary coil 3 will be opposite to the voltage in the primary coil 3, ensuring the normal operation of the three-phase system of alternating current.

[0046] Based on the above embodiments, another embodiment of the utility model is that an isolation distance is set between the primary coil 2 and the secondary coil 3. On the one hand, the isolation distance and the insulating material can reduce the electromagnetic interference between the coils, thereby ensuring the output quality of the transformer and the stable operation of the equipment. On the other hand, it can prevent the risk of electrical short circuit or breakdown, and provide additional mechanical support to reduce the movement or deformation of the coil due to vibration or impact, thereby improving the mechanical stability and durability of the transformer.

[0047] For reference, since there is a voltage difference between the primary coil 2 and the secondary coil 3, in order to prevent current leakage between the primary coil 2 and the secondary coil 3, the above isolation gap is filled with insulating material. By filling the isolation gap with insulating material, different voltage levels can be effectively isolated, so that effective insulation can reduce the risk of electric shock and improve the personal safety protection level of the equipment. Avoid accidental contact between the primary coil 2 and the secondary coil 3, and avoid dangerous conductive paths.

[0048] During operation, the primary coil 2 and the secondary coil 3 may generate heat. Insulating materials can isolate heat propagation to a certain extent, helping to protect the temperatures of different coils from affecting each other. At the same time, an isolation distance is set between the primary coil 2 and the secondary coil 3, and insulating materials are filled in this distance, which generally does not affect the normal operation of the coils. The working efficiency of the device mainly depends on the magnetic properties of the core material and the resistance loss of the coil. Therefore, the insulating material filled between the primary coil 2 and the secondary coil 3 is often a material with good electrical insulation but low magnetic permeability, so it will not significantly affect the coupling performance of the magnetic circuit between the two coils.

[0049] It is worth noting that some insulating materials will increase the distance between the primary coil 2 and the secondary coil 3 to a certain extent, but as long as this distance does not affect the magnetic induction between the coils too much, the coupling performance of the coils will not be greatly affected. In practical applications, technicians can select insulators of appropriate thickness and material as needed, such as epoxy resin, polyester film, polytetrafluoroethylene or glass fiber.

[0050] The "one embodiment", "another embodiment", "embodiment", "preferred embodiment" and the like mentioned in this specification refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when a specific feature, structure or characteristic is described in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of the utility model.

[0051] Although the utility model is described herein with reference to a plurality of illustrative embodiments of the utility model, it should be understood that those skilled in the art may devise many other modifications and implementations that fall within the scope and spirit of the principles disclosed herein. More specifically, within the scope of the disclosure, drawings, and claims of the present application, various modifications and improvements may be made to the components and / or layout of the subject combination layout. In addition to the modifications and improvements made to the components and / or layout, other uses will also be apparent to those skilled in the art.

Claims

1. A current balancing device for the power supply side, the device is used to evenly distribute the current of a single-phase load to a three-phase circuit, characterized in that: The device comprises an iron core body (1), wherein a plurality of primary coils (2) are sleeved on the iron core body (1), and two adjacent primary coils (2) are connected in a star shape; the primary coils (2) are used to connect the circuit on the power supply side; a plurality of secondary coils (3) are sleeved on the iron core body (1), and two adjacent secondary coils (3) are connected in series, and the secondary coils (3) are used to connect the circuit on the output side; the iron core body (1) comprises a lower iron core (101) and an upper iron core (102), the upper iron core (102) is detachably connected to the lower iron core (101), the upper iron core (102) and the lower iron core (101) are both E-shaped, and the primary coils (2) and the secondary coils (3) are both wound on the lower iron core (101).

2. The current balancing device for the power supply side according to claim 1, characterized in that: There are three primary coils (2), and each primary coil (2) has the same number of turns; the number of secondary coils (3) corresponds to the number of primary coils (2), and each secondary coil (3) has the same number of turns.

3. The current balancing device for the power supply side according to claim 2, characterized in that: The secondary coil (3) comprises an input end and an output end, and the three secondary coils (3) are respectively coil L1, coil L2 and coil L3, the output end of coil L1 is connected to the input end of coil L2, and the output end of coil L2 is connected to the output end of coil L3.

4. The current balancing device for the power supply side according to claim 2, characterized in that: When the primary coil (2) is connected in star shape, the input side of the primary coil (2) should be connected to the three phases of a three-phase power supply respectively, and the output side of the primary coil (2) is connected to a common neutral point.

5. The current balancing device for power supply side according to claim 1, characterized in that: The primary coil (2) and the secondary coil (3) are arranged opposite to each other on the lower iron core (101), and electromagnetic induction is generated by the primary coil (2) and the secondary coil (3) on the lower iron core (101).

6. The current balancing device for the power supply side according to claim 5, characterized in that: The primary coil (2) and the secondary coil (3) are wound in opposite directions.

7. The current balancing device for power supply side according to claim 5, characterized in that: An isolation distance is provided between the primary coil (2) and the secondary coil (3), and an insulating material is filled between the isolation distances.

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