voltage regulating transformer

Abstract

The present invention discloses a voltage-regulating transformer. The voltage-regulating transformer includes a high-voltage winding, an excitation winding, a voltage-regulating structure, and at least two low-voltage windings. The voltage-regulating structure includes a voltage-regulating winding and a voltage-regulating switch. The low-voltage winding is magnetically coupled to the high-voltage winding. The high-voltage winding is connected in series with the voltage-regulating switch and then in parallel with the excitation winding. The voltage-regulating winding is magnetically coupled to the excitation winding. The voltage-regulating switch is used to adjust the number of turns of the voltage-regulating winding connected to the high-voltage side circuit. By arranging the voltage-regulating switch to be connected in series with the high-voltage winding and then in parallel with the excitation winding, the current on the tap lead can be reduced, the phenomenon of magnetic field overheating caused by the voltage-regulating structure can be improved, the required specifications of the tap lead can be reduced, the production difficulty can be reduced, and the production efficiency, production quality reliability, and operability of the adjustable transformer can be improved. At the same time, the number of voltage-regulating switches and voltage-regulating windings can be reduced, further improving the economic efficiency of the voltage-regulating transformer.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of transformers, and in particular to a voltage regulating transformer. Background Art

[0002] In the prior art, there are two ways to implement the tap-type voltage regulation function of a transformer's low-voltage winding: direct voltage regulation using the low-voltage regulating winding and indirect voltage regulation using a series winding. These two methods are less economical and less operable, and can easily cause overheating of surrounding components. Summary of the Invention

[0003] The present invention provides a voltage regulating transformer to improve the economy and operability of the voltage regulating transformer, improve the overheating phenomenon of structural parts in the voltage regulating transformer, and simplify the structure of the voltage regulating transformer.

[0004] In a first aspect, an embodiment of the present invention provides a voltage regulating transformer, comprising a high-voltage winding, an excitation winding, a voltage regulating structure, and at least two low-voltage windings, wherein the voltage regulating structure comprises a voltage regulating winding and a voltage regulating switch;

[0005] The low-voltage winding is magnetically coupled to the high-voltage winding, the high-voltage winding is connected in series with the voltage-regulating switch and then connected in parallel with the excitation winding, and the voltage-regulating winding is magnetically coupled to the excitation winding; wherein the voltage-regulating switch is used to adjust the number of winding turns of the voltage-regulating winding connected to the high-voltage side circuit.

[0006] Optionally, the polarity active end of the voltage regulating switch is connected to the first end of the high-voltage winding, the polarity fixed end of the voltage regulating switch is connected to the two ends of the voltage regulating winding, the tap fixed end of the voltage regulating switch is connected to the tap tap of the voltage regulating winding, the tap active end of the voltage regulating switch is connected to the first end of the excitation winding, serving as the end of the high-voltage side single-phase winding, and the second end of the excitation winding is connected to the second end of the high-voltage winding, serving as the head end of the high-voltage side single-phase winding.

[0007] Optionally, the voltage regulating transformer further includes a first iron core and a second iron core;

[0008] The high-voltage winding and the low-voltage winding are wound on the first iron core; the voltage-regulating winding and the excitation winding are wound on the second iron core.

[0009] Optionally, the excitation winding and the voltage regulating winding are arranged on the second iron core from the inside to the outside.

[0010] Optionally, the connection mode of the high-voltage side winding is star connection or delta connection, and the winding on the high-voltage side includes the high-voltage winding, the voltage regulating winding and the excitation winding.

[0011] Optionally, the excitation winding includes a first-phase excitation winding, a second-phase excitation winding and a third-phase excitation winding; when the high-voltage side winding is connected in a star connection, the first ends of the excitation windings of different phases are connected to serve as the neutral point of the high-voltage side winding; when the high-voltage side winding is connected in a triangle connection, the first end of the first-phase excitation winding is connected to the second end of the second-phase excitation winding, the first end of the second-phase excitation winding is connected to the second end of the third-phase excitation winding, and the first end of the third-phase excitation winding is connected to the second end of the first-phase excitation winding.

[0012] Optionally, at least two of the low-voltage windings are connected in different ways.

[0013] Optionally, the low-voltage winding is connected in a star connection, a delta connection or a zigzag connection.

[0014] Optionally, the winding direction of the excitation winding is the same as or opposite to that of the voltage regulating winding.

[0015] Optionally, the ratio of the number of turns of the voltage regulating winding to the number of turns of the high-voltage winding is the voltage regulating range of the voltage regulating transformer.

[0016] The technical solution of the embodiment of the present invention is to provide a voltage regulating switch connected in series with the high-voltage winding and then in parallel with the excitation winding. The voltage across the high-voltage winding can be adjusted by adjusting the number of turns of the voltage regulating winding connected to the high-voltage side circuit via the voltage regulating switch. Furthermore, through the magnetic field coupling between the high-voltage and low-voltage windings, the voltage across the low-voltage winding can be adjusted, thus achieving voltage regulation on the low-voltage side of the voltage-regulating transformer. Because the voltage regulating structure is connected in series with the high-voltage winding, the current flowing through the voltage regulating structure is equal to the current flowing through the high-voltage winding. Compared to a case where the current flowing through the voltage regulating structure is equal to the current flowing through the low-voltage winding, this reduces the current flowing through the voltage regulating structure and alleviates the magnetic field overheating caused by the voltage regulating structure. This eliminates the need for shielding structures, simplifies the structure of the voltage regulating transformer, and improves the economic efficiency of the voltage regulating transformer. Furthermore, the current flowing through the tapping lead in the voltage regulating structure can be reduced, thereby reducing the required tapping lead specifications, reducing production complexity, and improving the production efficiency, quality reliability, and operability of the variable transformer. Furthermore, the voltage-regulating structure is disposed on the high-voltage side, so only one voltage-regulating structure is required to regulate the voltages of at least two low-voltage windings. This reduces the number of voltage-regulating structures required, further reducing the cost of the voltage-regulating transformer and improving its economic efficiency. Furthermore, the voltage-regulating transformer provided by the present application does not require an additional series winding, thereby reducing the number of windings required for the voltage-regulating transformer, further reducing the cost of the voltage-regulating transformer and improving its economic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the winding structure of a voltage regulating transformer provided in the related art;

[0018] Figure 2 A schematic diagram of the winding structure of another voltage regulating transformer provided in the related art;

[0019] Figure 3 A schematic diagram of the winding structure of a voltage regulating transformer provided in an embodiment of the present invention;

[0020] Figure 4 A schematic diagram of the winding structure of another voltage-regulating transformer provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0022] Figure 1 A schematic diagram of the winding structure of a voltage regulating transformer is provided for related technology. Figure 1 As shown, the voltage regulating transformer includes a high-voltage winding, two low-voltage windings, two low-voltage regulating windings and two voltage regulating switches; the two voltage regulating switches are respectively set on the two low-voltage regulating windings, and then the low-voltage regulating windings are connected in series with the low-voltage windings, so that the number of turns of the low-voltage regulating winding connected to the low-voltage side circuit is adjusted by the voltage regulating switches, and then the turns ratio of the high-voltage side winding and the low-voltage side winding is adjusted to achieve voltage regulation on the low-voltage side. For example, as Figure 1As shown, the three-phase high-voltage windings of the high-voltage winding are AX, BY and CZ connected in star shape, and the neutral point is O. After the three-phase low-voltage winding of the first low-voltage winding is connected in star shape, one end of the three-phase low-voltage winding is respectively connected to the three movable terminals a1k, b1k and c1k of the polarity selector of the first voltage regulating switch, and the three sets of fixed terminals of the polarity selector are respectively connected to the two ends of the three-phase low-voltage winding; the other ends of the three-phase low-voltage winding serve as the three-phase low-voltage line terminals a1, b1 and c1 of the low-voltage winding, respectively. The tap selector of the first voltage regulating switch includes three sets of tap terminals (the first set of tap terminals is x11, x12, x13...x1n, x1n+1; the second set of tap terminals is y11, y12, y13...y1n, y1n+1; the third set of tap terminals is z11, z12, z13...z1n, z1n+1), which are respectively connected to the tap taps of each phase of the low-voltage regulating winding. The three connection terminals of the tap selector of the first voltage regulating switch are connected to each other to serve as the neutral point o of the first low-voltage winding. After the three-phase low-voltage winding of the second low-voltage winding is connected in a triangle, one end of the three-phase low-voltage winding is respectively connected to the three active terminals a2k, b2k and c2k of the polarity selector of the second voltage regulating switch, and the three groups of fixed terminals of the polarity selector are respectively connected to the two ends of the three-phase low-voltage winding; the other ends of the three-phase low-voltage winding serve as the three-phase low-voltage line terminals a2, b2 and c2 of the low-voltage winding, and the tap selector of the second voltage regulating switch includes three groups of tap terminals (the first group of tap terminals is x21, x22, x23...x2n, x2n+1; the second group of tap terminals is y21, y22, y23...y2n, y2n+1; the third group of tap terminals is z21, z22, z23...z2n, z2n+1), which are respectively connected to the tap taps of each phase low-voltage regulating winding, and the three connection terminals of the tap selector of the second voltage regulating switch are respectively connected to the low-voltage winding of another phase. Figure 1 In this structure, the number of voltage regulators is equal to the number of low-voltage windings, resulting in poor economic efficiency. The currents flowing in the tap leads and low-voltage windings are high, requiring larger cables and a large number of tap leads. This makes bending and securing these leads difficult during production, resulting in low production efficiency and high overall lead cable costs. During extreme tap voltage regulation, the tap wires have a high ampere-turn count, which can easily cause overheating of surrounding components. Countermeasures (such as copper and magnetic shielding) are necessary, adding a degree of complexity to the structure of the voltage-regulating transformer.

[0023] Figure 2 Another winding structure diagram of a voltage regulating transformer provided in the related art. Figure 2 As shown, Figure 1The difference is that the voltage-regulating transformer consists of a regulating winding and a voltage-regulating switch (the three active terminals of the voltage-regulating switch's polarity selector are labeled ak, bk, and ck, respectively, and the three sets of tapping terminals of the voltage-regulating switch's tap selector are labeled x1, x2, x3...xn, xn+1; y1, y2, y3...yn, yn+1; z1, z2, z3...zn, zn+1, respectively). It also includes an excitation winding and two series windings. After the voltage-regulating switch is connected to the regulating winding, it is connected in series with the three excitation windings in the excitation winding. Each series winding is connected in series with each low-voltage winding. The voltage on the low-voltage side of the voltage-regulating transformer is the sum of the voltage across the series winding and the voltage across the low-voltage winding. There is magnetic field coupling between the high-voltage winding and the regulating winding, and between the excitation winding and the series winding. The turns ratio between the high-voltage winding and the voltage regulating winding can be adjusted by the voltage regulating switch, thereby adjusting the voltage across the voltage regulating winding, and further adjusting the voltage across the excitation winding. The turns ratio between the excitation winding and the series winding remains unchanged. When the voltage across the excitation winding changes, the voltage across the series winding can be changed, thereby adjusting the low-voltage side voltage of the voltage regulating transformer. Figure 2 In this structure, each low-voltage winding requires an additional series winding, which increases the number of windings required for the voltage-regulating transformer, increases material and labor costs, and reduces the economic efficiency of the voltage-regulating transformer. Furthermore, the number of connecting wires between the low-voltage winding and the series winding is relatively large, and the problem of structural component overheating caused by the high ampere-turns also needs to be considered.

[0024] In response to the above technical problems, an embodiment of the present invention provides a voltage regulating transformer. Figure 3 Schematic diagram of the winding structure of a voltage regulating transformer provided by an embodiment of the present invention. Figure 3 As shown, the voltage-regulating transformer includes a high-voltage winding 10, an excitation winding 20, a voltage-regulating structure 30 and at least two low-voltage windings 40. The voltage-regulating structure 30 includes a voltage-regulating winding and a voltage-regulating switch. The low-voltage winding 40 is magnetically coupled with the high-voltage winding 10. The high-voltage winding 10 is connected in series with the voltage-regulating switch and then connected in parallel with the excitation winding 20. The voltage-regulating winding is magnetically coupled with the excitation winding 20. The voltage-regulating switch is used to adjust the number of turns of the voltage-regulating winding connected to the high-voltage side circuit.

[0025] Specifically, the high-voltage winding 10, the excitation winding 20, and the low-voltage winding 40 all include three-phase windings. The voltage regulating structure 30 includes three voltage regulating substructures, each of which is provided with a voltage regulating winding, which is connected in series with the three-phase high-voltage winding and then connected to the excitation winding. Then, the second end A1 of the high-voltage winding of the first phase is connected to the second end A' of the excitation winding of the first phase, the first end of the high-voltage winding of the first phase is connected to the first end AK of the voltage regulating substructure of the first phase, and the second end of the voltage regulating substructure of the first phase is connected to the first end X1 of the excitation winding of the first phase. Similarly, the second end B1 of the high-voltage winding of the second phase is connected to the second end B' of the excitation winding of the second phase, the first end of the high-voltage winding of the second phase is connected to the first end BK of the voltage regulating substructure of the second phase, and the second end of the voltage regulating substructure of the second phase is connected to the first end Y1 of the excitation winding of the second phase. The second end C1 of the third-phase high-voltage winding is connected to the second end C' of the third-phase excitation winding. The first end of the third-phase high-voltage winding is connected to the first end CK of the third-phase voltage-regulating substructure, and the second end of the third-phase voltage-regulating substructure is connected to the first end Z1 of the third-phase excitation winding. The second end of the high-voltage winding serves as the high-voltage line terminal of the high-voltage winding 10. The high-voltage winding 10 is connected in series with the winding in the voltage-regulating structure 30 connected to the high-voltage side circuit, and then connected in parallel with the excitation winding 20. According to Kirchhoff's second law of circuits, the sum of the voltage across the high-voltage winding 10 and the voltage across the winding in the voltage-regulating structure 30 connected to the high-voltage side circuit equals the voltage across the excitation winding 20. When high voltage is input to the high-voltage line terminal of the high-voltage winding 10, the number of turns of the excitation winding 20 remains unchanged. According to Faraday's law of electromagnetic induction, the voltage across the excitation winding 20 remains unchanged. The voltage-regulating structure 30 includes a winding that is magnetically coupled to the excitation winding 20. When the number of turns of the winding connected to the high-voltage side circuit of the voltage regulating structure 30 changes, the turns ratio of the winding in the voltage regulating structure 30 to the excitation winding 20 changes, causing the voltage across the voltage regulating structure 30 to change, and thus causing the voltage across the high-voltage winding 10 to change in the opposite direction to the voltage across the voltage regulating structure 30. The low-voltage winding 40 is connected to the high-voltage winding 10 by magnetic field coupling. When the voltage across the high-voltage winding 10 changes, the voltage across the low-voltage winding 40 changes along with the voltage across the high-voltage winding 10. Therefore, the voltage across the high-voltage winding 10 can be adjusted by the voltage regulating structure 30, and the voltage across the low-voltage winding 40 can be adjusted, thereby achieving voltage regulation on the low-voltage side of the voltage regulating transformer. Because the voltage regulating structure 30 is connected in series with the high-voltage winding 10, the current in the voltage regulating structure 30 is equal to the current in the high-voltage winding 10. Compared to the case where the current in the voltage regulating structure 30 is equal to the current in the low-voltage winding 40, the current in the voltage regulating structure 30 can be reduced, and the phenomenon of magnetic field overheating caused by the voltage regulating structure 30 can be improved. This can save the shielding structure, simplify the structure of the voltage regulating transformer, and improve the economic efficiency of the voltage regulating transformer. For example, the shielding structure can include a magnetic shielding structure and a copper shielding structure.At the same time, the current on the tapping lead required in the voltage regulating structure 30 can be reduced, thereby reducing the specifications required for the tapping lead, reducing the difficulty of production, and improving the production efficiency, production quality reliability, and operability of the adjustable transformer. Moreover, the voltage regulating structure 30 is arranged on the high-voltage side, and only one voltage regulating structure 30 is required to regulate the voltage of at least two low-voltage windings 40, reducing the number of voltage regulating structures 30 required, further reducing the cost of the voltage regulating transformer, and improving the economic efficiency of the voltage regulating transformer. In addition, the voltage regulating transformer provided by the present application does not require additional series windings, thereby reducing the number of windings required for the voltage regulating transformer, further reducing the cost of the voltage regulating transformer, and improving the economic efficiency of the voltage regulating transformer.

[0026] The technical solution of this embodiment is to connect a voltage-regulating switch in series with the high-voltage winding and then in parallel with the excitation winding. The voltage across the high-voltage winding can be adjusted by adjusting the number of turns of the voltage-regulating winding connected to the high-voltage side circuit via the voltage-regulating switch. Furthermore, through the magnetic field coupling between the high-voltage and low-voltage windings, the voltage across the low-voltage winding can be adjusted, thus achieving voltage regulation on the low-voltage side of the voltage-regulating transformer. Because the voltage-regulating structure is connected in series with the high-voltage winding, the current flowing through the voltage-regulating structure is equal to the current flowing through the high-voltage winding. Compared to a case where the current flowing through the voltage-regulating structure is equal to the current flowing through the low-voltage winding, this reduces the current flowing through the voltage-regulating structure and mitigates the magnetic field overheating caused by the voltage-regulating structure. This eliminates the need for shielding, simplifies the structure of the voltage-regulating transformer, and improves the economic efficiency of the voltage-regulating transformer. Furthermore, the current flowing through the tapping lead in the voltage-regulating structure can be reduced, thereby reducing the required tapping lead specifications, reducing production complexity, and improving the production efficiency, quality reliability, and operability of the variable transformer. Furthermore, the voltage-regulating structure is disposed on the high-voltage side, so only one voltage-regulating structure is required to regulate the voltages of at least two low-voltage windings. This reduces the number of voltage-regulating structures required, further reducing the cost of the voltage-regulating transformer and improving its economic efficiency. Furthermore, the voltage-regulating transformer provided by the present application does not require an additional series winding, thereby reducing the number of windings required for the voltage-regulating transformer, further reducing the cost of the voltage-regulating transformer and improving its economic efficiency.

[0027] Continue to refer Figure 3 The polarity active end of the voltage regulating switch is connected to the first end of the high-voltage winding 10, the polarity fixed end of the voltage regulating switch is connected to the two ends of the voltage regulating winding, the tap fixed end of the voltage regulating switch is connected to the tap tap of the voltage regulating winding, the tap active end of the voltage regulating switch is connected to the first end of the excitation winding 20, serving as the end of the high-voltage side single-phase winding, and the second end of the excitation winding 20 is connected to the second end of the high-voltage winding 10, serving as the head end of the high-voltage side single-phase winding.

[0028] Specifically, the voltage regulating winding includes a three-phase voltage regulating winding. The voltage regulating switch includes three sub-switches, which are respectively connected to the three-phase voltage regulating windings, and are used to respectively adjust the number of winding turns of each phase voltage regulating winding connected to the high-voltage side circuit. Each sub-switch includes a polarity selector and a tap selector, and each voltage regulating winding may include at least two tap taps. The polarity selector can select the winding polarity of the voltage regulating winding connected to the high-voltage side circuit, and the tap selector can select the number of winding turns of the voltage regulating winding connected to the high-voltage side circuit. By controlling the polarity selector and the tap selector, the direction and number of turns of the voltage regulating winding connected to the high-voltage side circuit can be adjusted, so that the positive and negative and the size of the voltage at both ends of the voltage regulating winding can be adjusted, and then the voltage at both ends of the high-voltage winding can be adjusted, and finally the voltage at both ends of the low-voltage winding is adjusted according to the voltage at both ends of the high-voltage winding, so as to realize voltage regulation on the low-voltage side of the voltage regulating transformer. For example, refer to Figure 3 The second end A' of the first-phase excitation winding is connected to the second end A1 of the first-phase high-voltage winding, serving as the head end of the high-voltage side single-phase winding, i.e., the high-voltage line end, which can be connected to the power grid for high voltage input. The active polarity end of the first-phase voltage-regulating sub-switch serves as the first end AK of the first-phase voltage-regulating sub-structure and is connected to the first end of the first-phase high-voltage winding. The first polarity fixed end - of the first-phase voltage-regulating sub-switch is connected to the first end of the first-phase voltage-regulating winding, and the second polarity fixed end + of the first-phase voltage-regulating sub-switch is connected to the second end of the first-phase voltage-regulating winding. The n+1 tap fixed ends x'1, x'2, x'3...x'n, x'n+1 of the first-phase voltage-regulating sub-switch are each connected to the n+1 taps of the first-phase voltage-regulating winding via a tap lead. If the number of turns of the voltage-regulating winding corresponding to the first and last taps is the same, the voltage-regulating range of the first-phase voltage-regulating winding can be divided into n levels. When the voltage regulation range of each gear is m% relative to the rated voltage on the high-voltage side of the voltage-regulating transformer, the voltage regulation range of the voltage-regulating transformer is ±n×m% relative to the rated voltage on the high-voltage side of the voltage-regulating transformer. The tapping active end of the first-phase voltage-regulating sub-switch serves as the second end of the first-phase voltage-regulating sub-structure and is connected to the first end X1 of the first-phase excitation winding. As the terminal end of the high-voltage-side single-phase winding, it can be connected to the second end of the excitation winding of another phase or the first end of the excitation winding of another phase, achieving a delta connection or a star connection on the high-voltage side. During the voltage-regulating transformer's voltage regulation process, when the polarity active end of the first-phase voltage-regulating sub-switch is connected to the second polarity fixed end + and the tapping active end is connected to the first tap fixed end x'1, the voltage across the first-phase voltage-regulating winding is -n×m%×U1. U1 is the rated voltage on the high-voltage side. The excitation winding voltage of the first phase is the rated voltage U1 on the high-voltage side, and the voltage across the high-voltage winding of the first phase is: [1-(-n×m%)]×U1; before voltage regulation, when the rated voltage of the low-voltage winding is U2, then under the current voltage regulation conditions, according to Faraday's law of electromagnetic induction, the voltage of the low-voltage winding is U2×(1+n×m%). Figure 3 The example in the figure shows a voltage-regulating transformer including two low-voltage windings 40. Before voltage regulation, the rated voltages of the first and second low-voltage windings 40 are U21 and U22, respectively. Under the current voltage regulation conditions, the voltage of the first low-voltage winding 40 is U21 × (1 + n × m%), and the voltage of the second low-voltage winding 40 is U22 × (1 + n × m%). When the active polarity terminal of the first-phase voltage-regulating sub-switch is connected to the first polarity fixed terminal -, and the active tap terminal is connected to the last tap fixed terminal x'n+1, the voltage across the first-phase voltage-regulating winding is n × m% × U1. U1 is the rated voltage on the high-voltage side. The excitation winding voltage of the first phase is the rated voltage U1 of the high-voltage side, and the voltage across the high-voltage winding of the first phase is: [1-(n×m%)]×U1; before voltage regulation, when the rated voltage of the low-voltage winding is U2, then under the current voltage regulation conditions, according to Faraday's law of electromagnetic induction, the voltage of the low-voltage winding is U2×(1-n×m%). Figure 3 The example in FIGURE 4 illustrates a voltage-regulating transformer including two low-voltage windings 40. Before voltage regulation, the rated voltages of the first low-voltage winding 40 and the second low-voltage winding 40 are U21 and U22, respectively. Under current voltage regulation conditions, the voltage of the first low-voltage winding 40 is U21 × (1-n × m%), and the voltage of the second low-voltage winding 40 is U22 × (1-n × m%). Furthermore, when the rated capacity of the voltage-regulating transformer is S, the capacity of each phase of the high-voltage winding 10 and the low-voltage winding 40 is S / 3. When the voltage regulation range of the voltage regulating winding is ±n×m%, the capacity of the voltage regulating winding is (n×m%) / (1-n×m%) of the capacity of the high-voltage winding, the voltage range of the voltage regulating winding is n×m% of the voltage of the excitation winding, the voltage range of the high-voltage winding is 1-n×m% of the voltage of the excitation winding, and the voltage range of the voltage regulating winding is (n×m%) / (1-n×m%) of the voltage of the high-voltage winding.

[0029] Similarly, the second end B' of the second-phase excitation winding is connected to the second end B1 of the second-phase high-voltage winding, serving as the head end of the high-voltage-side single-phase winding, i.e., the high-voltage line end, which can be connected to the power grid for high voltage input. The active polarity end of the second-phase voltage-regulating sub-switch serves as the first end BK of the second-phase voltage-regulating sub-structure and is connected to the first end of the second-phase high-voltage winding. The first polarity fixed end - of the second-phase voltage-regulating sub-switch is connected to the first end of the second-phase voltage-regulating winding, and the second polarity fixed end + of the second-phase voltage-regulating sub-switch is connected to the second end of the second-phase voltage-regulating winding. The n+1 tap fixed ends y'1, y'2, y'3...y'n, y'n+1 of the second-phase voltage-regulating sub-switch are each connected to the n+1 taps of the second-phase voltage-regulating winding via a tap lead. The tapped active end of the second-phase voltage-regulating sub-switch serves as the second end of the second-phase voltage-regulating sub-structure, connected to the first end Y1 of the second-phase excitation winding. As the terminal end of the high-voltage-side single-phase winding, it can be connected to the second end of another phase's excitation winding or the first end of another phase's excitation winding, achieving a delta or star connection on the high-voltage side. The second end C' of the third-phase excitation winding is connected to the second end C1 of the third-phase high-voltage winding, serving as the head end of the high-voltage-side single-phase winding, i.e., the high-voltage line end, which can be connected to the power grid for high voltage input. The active polarity terminal of the third-phase voltage-regulating sub-switch serves as the first terminal CK of the third-phase voltage-regulating sub-structure and is connected to the first terminal of the third-phase high-voltage winding. The first polarity fixed terminal - of the third-phase voltage-regulating sub-switch is connected to the first terminal of the third-phase voltage-regulating winding. The second polarity fixed terminal + of the third-phase voltage-regulating sub-switch is connected to the second terminal of the third-phase voltage-regulating winding. The n+1 tap fixed terminals z'1, z'2, z'3, ..., z'n, z'n+1 of the third-phase voltage-regulating sub-switch are each connected to the n+1 taps of the third-phase voltage-regulating winding via a tap lead. The active tap terminal of the third-phase voltage-regulating sub-switch serves as the second terminal of the third-phase voltage-regulating sub-structure and is connected to the first terminal Z1 of the third-phase excitation winding. As the terminal of the high-voltage-side single-phase winding, it can be connected to the second terminal or the first terminal of the excitation winding of another phase, achieving a delta connection or a star connection on the high-voltage side. The voltage regulation process of the second phase and the voltage regulation process of the third phase are the same as the voltage regulation process of the first phase, and will not be repeated here.

[0030] Based on the above technical solution, the winding direction of the excitation winding is the same as that of the voltage regulating winding, so that when the polarity movable end of the first-phase voltage regulating sub-switch is connected to the second polarity fixed end + and the tap movable end is connected to the first tap fixed end x'1, the voltage on the first-phase voltage regulating winding is -n×m%×U1. When the polarity movable end of the first-phase voltage regulating sub-switch is connected to the first polarity fixed end - and the tap movable end is connected to the last tap fixed end x'n+1, the voltage on the first-phase voltage regulating winding is n×m%×U1. In some embodiments, the winding direction of the excitation winding can also be set opposite to that of the voltage regulating winding. When the polarity movable end of the first-phase voltage regulating sub-switch is connected to the second polarity fixed end + and the tap movable end is connected to the first tap fixed end x'1, the voltage on the first-phase voltage regulating winding is n×m%×U1. When the active polarity terminal of the first-phase voltage regulating sub-switch is connected to the first polarity fixed terminal -, and the active tap terminal is connected to the last tap fixed terminal x'n+1, the voltage across the first-phase voltage regulating winding is -n×m%×U1. Under the same voltage regulation conditions, the voltage regulating range of the voltage regulating transformer is reversed, and voltage regulation on the low-voltage side of the voltage regulating transformer can also be achieved.

[0031] In some embodiments, the ratio of the number of turns of the voltage regulating winding to the number of turns of the high-voltage winding is the voltage regulating range of the voltage regulating transformer.

[0032] Specifically, the voltage regulating winding is connected in series with the high-voltage winding so that the current of the voltage regulating winding is the same as that of the high-voltage winding. The number of turns of the voltage regulating winding is set to the product of the number of turns of the high-voltage winding and the voltage regulation range, so that the voltage variation range of the voltage regulating winding meets the voltage regulation range of the voltage regulating transformer. For example, when the voltage regulation range of the voltage regulating transformer is ±10%, the ratio of the number of turns of the voltage regulating winding to the number of turns of the high-voltage winding is 10%.

[0033] In some embodiments, the voltage-regulating transformer further includes a first core and a second core; the high-voltage winding and the low-voltage winding are wound on the first core; and the voltage-regulating winding and the excitation winding are wound on the second core.

[0034] Specifically, the high-voltage winding and the low-voltage winding can be arranged on the same iron core, so that the high-voltage winding and the low-voltage winding are magnetically coupled. The voltage regulating winding and the excitation winding can also be arranged on the same iron core, so that the voltage regulating winding and the excitation winding are magnetically coupled. Therefore, when the number of turns of the winding connected to the high-voltage side circuit of the voltage regulating winding changes, the voltage of the low-voltage winding can be adjusted by changing the voltage of the high-voltage winding.

[0035] For example, Table 1 is a structural performance comparison table of different voltage regulating transformers provided by an embodiment of the present invention, wherein method 1 is Figure 1 The structural performance of the voltage regulating transformer provided by method 2 is Figure 2The structural performance of the voltage regulating transformer provided by method 3 is Figure 3 The structural performance of the voltage-regulating transformer provided. The number of switches refers to the number of voltage-regulating switches, the number of cores refers to the number of cores required for the voltage-regulating transformer, the number of windings refers to the sum of the number of windings including the high-voltage winding, the excitation winding, the voltage-regulating winding, and the low-voltage winding, the tap lead cable specification refers to the diameter of the tap lead used to connect the tap tap of the voltage-regulating winding to the tap fixed end of the voltage-regulating switch, the production difficulty refers to the difficulty in the voltage-regulating switch production process, and the total cost refers to the cost required in the voltage-regulating transformer production process. As shown in Table 1, Figure 3 The number of windings required for the voltage regulating transformer provided is (N+3)×3, where N is the number of low voltage windings. Figure 1 The voltage regulating transformer and Figure 2 The number of voltage regulating transformers provided reduces the cost of the voltage regulating transformer and improves the economic efficiency of the voltage regulating transformer. Moreover, the current on the voltage regulating winding is equal to the current on the high voltage winding, which is less than Figure 1 The voltage regulating transformer and Figure 2 The invention provides a current on a voltage regulating winding and a tap lead in a voltage regulating transformer, thereby reducing the required specifications of the tap lead, and lowering the production difficulty and the total cost.

[0036]

[0037] Based on the above technical solution, the excitation winding and the voltage regulating winding are arranged on the second core from the inside to the outside, which can prevent the excitation winding from affecting the wiring of the voltage regulating winding and reduce the wiring difficulty of the voltage regulating winding.

[0038] In some embodiments, the high-voltage side winding is connected in a star connection or a delta connection, and the high-voltage side winding includes a high-voltage winding, a voltage regulating winding, and an excitation winding.

[0039] Specifically, such as Figure 3 As shown, in the same phase on the high-voltage side, the high-voltage winding is connected in series with the voltage regulating winding through a voltage regulating switch, and then connected in parallel with the excitation winding. At this time, the two ends of the excitation winding in each phase can serve as the high-voltage line ends of the high-voltage side winding. The excitation winding includes a first-phase excitation winding, a second-phase excitation winding, and a third-phase excitation winding; when the high-voltage side winding is connected in a star connection, the first ends of the excitation windings of different phases are connected to serve as the neutral point O1 of the high-voltage side winding. Specifically, the first end X1 of the first-phase excitation winding, the first end Y1 of the second-phase excitation winding, and the first end Z1 of the third-phase excitation winding are connected and serve as the neutral point O1 of the high-voltage side winding.

[0040] Figure 4 Schematic diagram of the winding structure of another voltage regulating transformer provided by an embodiment of the present invention. Figure 4As shown, the high-voltage side windings are connected in a delta configuration. Specifically, the first end X1 of the first-phase excitation winding is connected to the second end B' of the second-phase excitation winding, the first end Y1 of the second-phase excitation winding is connected to the second end C' of the third-phase excitation winding, and the first end Z1 of the third-phase excitation winding is connected to the second end A' of the first-phase excitation winding.

[0041] Continue to refer Figure 3 and Figure 4 , the connection modes of at least two low-voltage windings 40 are different.

[0042] Specifically, Figure 3 and Figure 4 The figure shows an exemplary voltage-regulating transformer including two low-voltage windings 40. One of the low-voltage windings 40 is connected in a star connection, and the other low-voltage winding 40 is connected in a delta connection. By setting different connection methods for the low-voltage windings 40, different low-voltage windings 40 can output different voltages, thereby increasing the range of use of the voltage-regulating transformer. For example, each low-voltage winding 40 includes a three-phase low-voltage winding. When the first low-voltage winding 40 is connected in a star connection, the first end x1' of the first-phase low-voltage winding, the first end y1' of the second-phase low-voltage winding, and the first end z1' of the third-phase low-voltage winding are connected and serve as the neutral point o1 of the first low-voltage winding 40. The second end of the first-phase low-voltage winding serves as the low-voltage line terminal a'1 of the first-phase low-voltage winding, the second end of the second-phase low-voltage winding serves as the low-voltage line terminal b'1 of the second-phase low-voltage winding, and the second end of the third-phase low-voltage winding serves as the low-voltage line terminal c'1 of the third-phase low-voltage winding. When the second low-voltage winding 40 is connected in a delta configuration, the second end of the first-phase low-voltage winding serves as the low-voltage line terminal a'2 of the first-phase low-voltage winding, the second end of the second-phase low-voltage winding serves as the low-voltage line terminal b'2 of the second-phase low-voltage winding, and the second end of the third-phase low-voltage winding serves as the low-voltage line terminal c'2 of the third-phase low-voltage winding. The first end x2' of the first-phase low-voltage winding is connected to the second end of the second-phase low-voltage winding, the first end y2' of the second-phase low-voltage winding is connected to the second end of the third-phase low-voltage winding, and the first end z2' of the third-phase low-voltage winding is connected to the second end of the first-phase low-voltage winding.

[0043] In some embodiments, the low voltage winding is connected in a star connection, a delta connection or a zigzag connection.

[0044] Continue to refer Figure 3 and Figure 4 , exemplarily showing the connection modes of the two low-voltage windings 40 including star connection and delta connection. In other embodiments, the connection mode of the low-voltage windings 40 can also be set to a zigzag connection, in which case the connection group number of the low-voltage windings 40 can be z.

[0045] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A voltage regulating transformer, characterized in that: It includes a high-voltage winding, an excitation winding, a voltage regulating structure and at least two low-voltage windings, wherein the voltage regulating structure includes a voltage regulating winding and a voltage regulating switch; The low-voltage winding is magnetically coupled to the high-voltage winding, the first end of the high-voltage winding is connected in series with the polarity active end of the voltage regulating switch and then connected in parallel with the excitation winding, and the voltage regulating winding is magnetically coupled to the excitation winding; the first end of the excitation winding serves as the end of the high-voltage side single-phase winding, and the second end of the excitation winding is connected to the second end of the high-voltage winding and serves as the head end of the high-voltage side single-phase winding; wherein the voltage regulating switch is used to adjust the number of turns of the voltage regulating winding connected to the high-voltage side circuit; The polarity fixed end of the voltage regulating switch is connected to the two ends of the voltage regulating winding, the tap fixed end of the voltage regulating switch is connected to the tap of the voltage regulating winding, and the tap movable end of the voltage regulating switch is connected to the first end of the excitation winding.

2. The voltage regulating transformer according to claim 1, characterized in that: Also includes a first core and a second core; The high-voltage winding and the low-voltage winding are wound on the first iron core; the voltage-regulating winding and the excitation winding are wound on the second iron core.

3. The voltage regulating transformer according to claim 2, characterized in that: The excitation winding and the voltage regulating winding are arranged on the second iron core from the inside to the outside.

4. The voltage regulating transformer according to any one of claims 1 to 3, characterized in that: The connection mode of the high-voltage side winding is star connection or delta connection, and the winding on the high-voltage side includes the high-voltage winding, the voltage regulating winding and the excitation winding.

5. The voltage regulating transformer according to claim 4, characterized in that: The excitation winding includes a first-phase excitation winding, a second-phase excitation winding and a third-phase excitation winding; When the connection mode of the high-voltage side winding is star connection, the first ends of the excitation windings of different phases are connected to serve as the neutral point of the high-voltage side winding; When the connection mode of the high-voltage side winding is a triangle connection, the first end of the first phase excitation winding is connected to the second end of the second phase excitation winding, the first end of the second phase excitation winding is connected to the second end of the third phase excitation winding, and the first end of the third phase excitation winding is connected to the second end of the first phase excitation winding.

6. The voltage regulating transformer according to claim 1, characterized in that: At least two of the low-voltage windings are connected in different ways.

7. The voltage regulating transformer according to claim 6, characterized in that: The connection mode of the low voltage winding is star connection, triangle connection or zigzag connection.

8. The voltage regulating transformer according to claim 1, characterized in that: The winding direction of the excitation winding is the same as or opposite to that of the voltage regulating winding.

9. The voltage regulating transformer according to claim 1, characterized in that: The ratio of the number of turns of the voltage regulating winding to the number of turns of the high-voltage winding is the voltage regulating range of the voltage regulating transformer.

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