A low-pressure voltage regulator

Abstract

The present invention provides a low-voltage voltage regulator, which relates to the technical field of low-voltage voltage regulation and includes: a common winding, a series winding, and a voltage regulation switch. Among them, the voltage regulation switch includes: a first switch and a second switch. The first end of the common winding is respectively connected to a first voltage input terminal N and a first voltage output terminal N'. The second end of the common winding is connected to the first switch. The first switch is respectively connected to a second voltage input terminal L, the first end of the second switch, and the first end of the series winding. The second end of the series winding is respectively connected to the second end of the second switch and a second voltage output terminal L', solving the technical problem that the material utilization rate of the existing low-voltage voltage regulator using the neutral wire voltage regulation technology is low, resulting in a relatively high cost of the low-voltage voltage regulator.

Description

Technical Field

[0001] The present invention relates to the technical field of low - voltage voltage regulation, and in particular, to a low - voltage voltage regulator. Background Art

[0002] Compared with medium - voltage and high - voltage distribution networks, the low - voltage distribution network transmits the same amount of energy, and the current flowing in the line is the largest. When the low - voltage distribution line is slightly longer, the voltage drop generated on the line will be excessive, and the voltage at the user end will become low. An excessively low voltage will cause electrical equipment to malfunction, increase the motor current, raise the winding temperature, and even burn out the motor severely in serious cases.

[0003] Using an on - load tap - changing distribution transformer with automatic voltage regulation can only ensure that the starting voltage of the low - voltage distribution network is qualified, and the voltage of the end - user with a long power supply radius in the low - voltage line is still too low. Therefore, using a low - voltage voltage regulator can effectively solve the problem of low voltage at the end - user.

[0004] Current low - voltage voltage regulator products include compensated AC voltage regulators, contactless AC voltage regulators, and neutral - line voltage regulators: Compensated voltage regulators are carbon - brush moving - contact - type voltage regulators, which have disadvantages such as slip - point mechanical friction and arcing at the slip - point connection; The control method of contactless AC voltage regulators is to adjust the voltage through the conduction state of IGBTs. Its main disadvantages are complex control and high cost and uneconomical. Moreover, in the above two voltage regulators, the transformer is in a working state for a long time, with relatively large no - load losses and load losses. The neutral - line voltage regulation method adjusts the number of turns of the common - end winding, and the material utilization rate is relatively low, resulting in low economy.

[0005] In view of the above problems, no effective solution has been proposed yet. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a low - voltage voltage regulator to alleviate the technical problem that the low - voltage voltage regulator using the neutral - line voltage regulation technology has a low material utilization rate, resulting in a high cost of the low - voltage voltage regulator.

[0007] In a first aspect, an embodiment of the present invention provides a low - voltage voltage regulator, including: a common winding, a series winding, and a voltage - regulating switch. Among them, the voltage - regulating switch includes: a first switch and a second switch. The first end of the common winding is respectively connected to a first voltage input terminal N and a first voltage output terminal N'. The second end of the common winding is connected to the first switch. The first switch is respectively connected to a second voltage input terminal L, the first end of the second switch, and the first end of the series winding. The second end of the series winding is respectively connected to the second end of the second switch and a second voltage output terminal L'.

[0008] Further, when the first switch is off and the second switch is on, the input voltage of the low-voltage regulator is equal to the output voltage of the low-voltage regulator.

[0009] Further, when the first switch is on and the second switch is off, the low-voltage regulator boosts the input voltage to obtain the output voltage, where the ratio between the input voltage and the output voltage is equal to the ratio between the number of turns of the common winding and a first target number, and the first target number is the sum of the number of turns of the common winding and the number of turns of the series winding.

[0010] Further, the voltage regulating switch further includes: a third switch, the moving contact of the third switch is respectively connected to the second voltage output terminal L' and the second switch, and the static contact of the third switch is used to connect to any tap of the series winding or the second end of the series winding.

[0011] Further, when the first switch is off and the second switch is on, the input voltage of the low-voltage regulator is equal to the output voltage of the low-voltage regulator.

[0012] Further, when the first switch is on and the second switch is off, the low-voltage regulator boosts the input voltage to obtain the output voltage, where the ratio between the input voltage and the output voltage is equal to the ratio between the number of turns of the common winding and a second target number, and the second target number is the sum of the number of turns of the common winding and the first current number of turns of the series winding, and the first current number of turns of the series winding is the number of turns between the first end of the series winding and a first target tap, and the first target tap is any tap of the series winding.

[0013] Further, if the first switch is connected to a second target tap of the series winding and the static contact is connected to a third target tap, then when the first switch is on and the second switch is off, the low-voltage regulator steps down the input voltage to obtain the output voltage, where the second target tap is any tap of the series winding, the third target tap is any tap between the second target tap and the first end of the series winding or the first end of the series winding, and the ratio between the output voltage and the input voltage is the ratio between a third target number and the number of turns of the common winding, and the third target number is the difference between the number of turns of the common winding and the second current number of turns of the series winding, and the second current number of turns of the series winding is the number of turns between the second target tap and the third target tap.

[0014] Further, if the first switch is connected to the second target tap of the series winding and the static contact is connected to the fourth target tap, then when the first switch is closed and the second switch is open, the low-voltage voltage regulator boosts the input voltage to obtain an output voltage, where the fourth target tap is any tap between the second target tap and the second end of the series winding or the second end of the series winding, and the ratio between the output voltage and the input voltage is the ratio between the fourth target number and the number of turns of the common winding, where the fourth target number is the sum of the number of turns of the common winding and the third current number of turns of the series winding, and the third current number of turns of the series winding is the number of turns between the second target tap and the fourth target tap.

[0015] Further, the first switch and the second switch are vacuum switches.

[0016] Further, the third switch is an air switch or an oil-immersed switch.

[0017] The low-voltage voltage regulator in the embodiment of the present invention includes: a common winding, a series winding, and a voltage regulating switch, where the voltage regulating switch includes: a first switch and a second switch. The first end of the common winding is respectively connected to the first voltage input terminal N and the first voltage output terminal N'. The second end of the common winding is connected to the first switch. The first switch is respectively connected to the second voltage input terminal L, the first end of the second switch, and the first end of the series winding. The second end of the series winding is respectively connected to the second end of the second switch and the second voltage output terminal L'. The low-voltage voltage regulator in the present application does not adopt the principle of a compensated voltage regulator and brush regulation, and there are no disadvantages such as slip mechanical friction and arcing at the slip connection points. In addition, power electronic devices such as IGBTs are not used, and the control is simple. Further, compared with the existing low-voltage voltage regulator with neutral line voltage regulation, the low-voltage voltage regulator in the present application achieves the purpose of high material utilization rate, thereby solving the technical problem that the low material utilization rate of the existing low-voltage voltage regulator using neutral line voltage regulation technology leads to a high cost of the low-voltage voltage regulator, and thus realizing the technical effect of reducing the manufacturing cost of the low-voltage voltage regulator.

[0018] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention are achieved and obtained by the structures specifically pointed out in the specification, the claims, and the drawings.

[0019] To make the above objectives, features, and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given, and in conjunction with the accompanying drawings, the detailed description is as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 Schematic diagram of the first low-pressure regulator provided by an embodiment of the present invention;

[0022] Figure 2 Schematic diagram of the second low-pressure regulator provided by an embodiment of the present invention;

[0023] Figure 3 Schematic diagram of the first pressure regulation state of the second low-pressure regulator provided by an embodiment of the present invention;

[0024] Figure 4 Schematic diagram of the second pressure regulation state of the second low-pressure regulator provided by an embodiment of the present invention;

[0025] Figure 5 Schematic diagram of the third pressure regulation state of the second low-pressure regulator provided by an embodiment of the present invention;

[0026] Figure 6 Schematic diagram of the fourth pressure regulation state of the second low-pressure regulator provided by an embodiment of the present invention;

[0027] Figure 7 Schematic diagram of the fifth pressure regulation state of the second low-pressure regulator provided by an embodiment of the present invention;

[0028] Figure 8 Schematic diagram of the sixth pressure regulation state of the second low-pressure regulator provided by an embodiment of the present invention;

[0029] Figure 9 Schematic diagram of the seventh pressure regulation state of the second low-pressure regulator provided by an embodiment of the present invention;

[0030] Figure 10 Schematic diagram of the eighth pressure regulation state of the second low-pressure regulator provided by an embodiment of the present invention;

[0031] Figure 11 Schematic diagram of the ninth pressure regulation state of the second low-pressure regulator provided by an embodiment of the present invention;

[0032] Figure 12 Schematic diagram of the existing low-pressure regulator provided by an embodiment of the present invention;

[0033] Figure 13 Schematic diagram of another existing low-pressure regulator provided by an embodiment of the present invention;

[0034] Figure 14 Schematic diagram of the third low-voltage voltage regulator provided by the embodiment of the present invention. Detailed implementation manners

[0035] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] Embodiment 1:

[0037] According to the embodiment of the present invention, an embodiment of a low-voltage voltage regulator is provided. Figure 1 It is a schematic diagram of a low-voltage voltage regulator according to the embodiment of the present invention. As Figure 1 shown, the low-voltage voltage regulator includes: a common winding 10, a series winding 20, and a voltage regulating switch 30. Among them, the voltage regulating switch 30 includes: a first switch 31 and a second switch 32. The first end of the common winding is respectively connected to a first voltage input terminal N and a first voltage output terminal N'. The second end of the common winding is connected to the first switch. The first switch is respectively connected to a second voltage input terminal L, the first end of the second switch, and the first end of the series winding. The second end of the series winding is respectively connected to the second end of the second switch and a second voltage output terminal L'.

[0038] The low-voltage voltage regulator in the embodiment of the present invention includes: a common winding, a series winding, and a voltage regulating switch. Among them, the voltage regulating switch includes: a first switch and a second switch. The first end of the common winding is respectively connected to a first voltage input terminal N and a first voltage output terminal N'. The second end of the common winding is connected to the first switch. The first switch is respectively connected to a second voltage input terminal L, the first end of the second switch, and the first end of the series winding. The second end of the series winding is respectively connected to the second end of the second switch and a second voltage output terminal L'. The low-voltage voltage regulator in the present application does not adopt the principle of a compensating voltage stabilizer and brush regulation, and there are no disadvantages such as slip point mechanical friction and arcing at the slip point connection. In addition, power electronic devices such as IGBTs are not used, and the control is simple. Further, compared with the existing low-voltage voltage regulators with neutral line voltage regulation, the low-voltage voltage regulator in the present application achieves the purpose of high material utilization rate, thereby solving the technical problem that the material utilization rate of the existing low-voltage voltage regulators using neutral line voltage regulation technology is low, resulting in a high cost of the low-voltage voltage regulator, and thus realizing the technical effect of reducing the manufacturing cost of the low-voltage voltage regulator.

[0039] It should be noted that in the embodiments of the present invention, preferably, the above-mentioned first switch and second switch are vacuum switches. By using vacuum switches for voltage regulation, it is realized to cut off the load current with long-life and maintenance-free vacuum switches, achieving the long life, maintenance-free property and economic efficiency of the voltage regulating switch as a whole.

[0040] In the embodiments of the present invention, when the first switch is disconnected and the second switch is closed, the input voltage of the low-voltage voltage regulator is equal to the output voltage of the low-voltage voltage regulator.

[0041] When the first switch is closed and the second switch is disconnected, the low-voltage voltage regulator boosts the input voltage to obtain the output voltage. Among them, the ratio between the input voltage and the output voltage is equal to the ratio between the number of turns of the common winding and the first target number, and the first target number is the sum of the number of turns of the common winding and the number of turns of the series winding.

[0042] In the embodiments of the present invention, a second type of low-voltage voltage regulator is provided, as Figure 2 shown. On the basis of the first type of low-voltage voltage regulator, the second type of low-voltage voltage regulator adds a third switch 33. The moving contact of the third switch is respectively connected to the second voltage output terminal L' and the second switch, and the static contact of the third switch is used to connect to any tap of the series winding or the second end of the series winding.

[0043] When the first switch is disconnected and the second switch is closed, the input voltage of the low-voltage voltage regulator is equal to the output voltage of the low-voltage voltage regulator.

[0044] When the first switch is closed and the second switch is disconnected, the low-voltage voltage regulator boosts the input voltage to obtain the output voltage. Among them, the ratio between the input voltage and the output voltage is equal to the ratio between the number of turns of the common winding and the second target number. Among them, the second target number is the sum of the number of turns of the common winding and the first current number of turns of the series winding, and the first current number of turns of the series winding is the number of turns between the first end of the series winding and the first target tap, and the first target tap is any tap among multiple taps.

[0045] Taking the number of taps being 1 as an example, the second type of low-voltage voltage regulator will be described below.

[0046] When the number of taps is 1, the second type of low-voltage voltage regulator can boost the input voltage in two steps, which can be set to boost by 5% and 10% respectively.

[0047] The low-voltage voltage regulator includes an autotransformer with a common winding and a series winding wound separately in the same winding direction. The number of turns of the common winding is, for example, 100, and the total number of turns of a series winding is, for example, 10. The tap is in the middle of the series winding, with 5 turns on each of the upper and lower parts. Additionally, it includes a voltage regulating switch composed of a first switch 31, a second switch 32, and a third switch 33.

[0048] The LN terminal is the input terminal, and the L'N' terminal is the output. The first switch 31 and the second switch 32 are controlled and linked by the same electromagnet; the third switch 33 is an oil-immersed switch controlled by another electromagnet.

[0049] When the voltage is normal, the low-voltage voltage regulator is in a normal state. The L terminal is conducted through the second switch 32. Since the first switch 31 is open, the lower winding of the autotransformer will not be excited, and the upper winding cannot be excited either because it is short-circuited through the second switch 32. The autotransformer is taken out of operation and no no-load or load losses will be generated. At this time, the third switch 33 selects the middle tap of the series winding.

[0050] When voltage regulation is required, the first type is to regulate to the first step-up gear, that is, the 5% step-up gear. The state before the operation is as Figure 3 shown. Then the first switch 31 first opens and enters the transition state as Figure 4 shown. The L terminal is conducted to L' through the series winding of the autotransformer. Then the first switch 31 closes and enters the state as Figure 5 shown. The lower winding of the autotransformer is also put into the circuit, achieving voltage step-up. During the above process, there is no situation of circuit disconnection, thus maintaining the power supply continuity.

[0051] When it is necessary to step up from the first step-up gear to the second gear, that is, the 10% step-up state. The state before the step-up is as Figure 6 shown. First, the first switch 31 opens to make the autotransformer stop working and enters the state as follows Figure 7 shown. The voltage input terminal L is connected to the L' output through the middle tap of the series winding and the third switch 33 to maintain the power supply continuity. Then the first switch 31 conducts and enters the state as Figure 8 shown. At this time, the series winding circuit and its third switch 33 are in a short-circuited state. Subsequently, the third switch 33 is adjusted to connect to the end of the series winding and enters the state as Figure 9 shown. During the adjustment process, since there is no current passing through this circuit, no large arc will erode the contacts, causing carbonization of the oil quality of the third switch. Then the first switch 31 opens, and the input terminal L is conducted to the output terminal L' through the series winding of the autotransformer and the third switch 33. At this time, the power supply continuity is still maintained and enters the state as Figure 10 shown. Then the first switch 31 closes to make the common winding of the autotransformer put in, so that the voltage regulator is in the second step-up gear of autotransformer voltage regulation and enters the state as Figure 11State. The process of adjusting back from the second gear to the first gear is the opposite process and will not be elaborated in the embodiments of the present application.

[0052] For the low-voltage voltage regulator in the prior art, its voltage regulation is mainly carried out at the center line N. As Figure 12 shown, when it needs to boost the voltage by 5%, the third switch 33 selects the lower part of the common winding; when boosting the voltage by 10%, the third switch 33 selects the middle part of the common winding. When the low-voltage voltage regulator in the prior art regulates the voltage by 10% and the input voltage of the present application is the same as that of the low-voltage voltage regulator in the prior art, the boosting effect is the same. However, only 50 turns of the common winding in the low-voltage voltage regulator in the prior art bear the input voltage, while 100 turns of the common winding in the present application bear the input voltage. According to the relevant knowledge of transformers, as Figure 13 shown, the turn voltage of the low-voltage voltage regulator in the prior art is twice that of the present application. When the magnetic flux density in the iron core is the same, the autotransformer iron core of the low-voltage voltage regulator in the prior art needs to be twice that of the present application. For example, when the total number of turns of the common winding and the series winding in the present application is 110 turns, the low-voltage voltage regulator in the prior art needs 105 turns, and the difference is not significant. If both use iron cores with the same cross-section, the total number of turns required for the low-voltage voltage regulator in the prior art is 210 turns. Therefore, the low-voltage voltage regulator in the prior art requires a higher manufacturing cost.

[0053] In the embodiments of the present invention, on the basis of the second low-voltage voltage regulator, a third low-voltage voltage regulator is proposed. Taking the number of taps being 1 as an example, the third low-voltage voltage regulator is as Figure 14 shown.

[0054] In the embodiments of the present invention, if the first switch is connected to the second target tap of the series winding and the static contact of the third switch is connected to the third target tap, then when the first switch is closed and the second switch is open, the low-voltage voltage regulator performs a step-down process on the input voltage to obtain an output voltage. Among them, the second target tap is any one of the multiple taps of the series winding, the third target tap is any one of the taps between the second target tap and the first end of the series winding or the first end of the series winding, and the ratio between the output voltage and the input voltage is the ratio between the third target quantity and the number of turns of the common winding. Among them, the third target quantity is the difference between the number of turns of the common winding and the second current number of turns of the series winding, and the second current number of turns is the number of turns between the second target tap and the third target tap.

[0055] If the first switch is connected to the second target tap of the series winding and the static contact of the third switch is connected to the fourth target tap, then when the first switch is closed and the second switch is open, the low-voltage regulator boosts the input voltage to obtain an output voltage. Here, the fourth target tap is any tap between the second target tap and the second end of the series winding or the second end of the series winding. The ratio between the output voltage and the input voltage is the ratio between the fourth target number and the number of turns of the common winding. Here, the fourth target number is the sum of the number of turns of the common winding and the number of turns of the third current coil of the series winding, and the number of turns of the third current coil is the number of turns between the second target tap and the fourth target tap.

[0056] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0058] In several embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. The device embodiments described above are only illustrative. For example, the division of units is only a logical function division, and there may be other division methods in actual implementation. For another example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection may be through some communication interfaces, and the indirect coupling or communication connection of the device or unit may be in an electrical, mechanical, or other form.

[0059] The unit described as a separation component may or may not be physically separated. The component displayed as a unit may or may not be a physical unit, that is, it may be located in one place or may be distributed over multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0060] In addition, each functional unit in various embodiments of the present invention may be integrated in a processing unit, may exist physically separately for each unit, or two or more units may be integrated in one unit.

[0061] Finally, it should be noted that the above embodiments are only specific implementation manners of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting it. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: any person skilled in the art within the technical scope disclosed by the present invention can still modify the technical solutions recorded in the foregoing embodiments or can easily think of changes, or perform equivalent replacements for some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A low-voltage voltage regulator, characterized in that, it includes: a common winding, a series winding and a voltage regulating switch, wherein, the voltage regulating switch includes: a first switch and a second switch, a first end of the common winding is respectively connected to a first voltage input terminal N and a first voltage output terminal N', a second end of the common winding is connected to the first switch, the first switch is respectively connected to a second voltage input terminal L, a first end of the second switch and a first end of the series winding, a second end of the series winding is respectively connected to a second end of the second switch and a second voltage output terminal L'; when the first switch is closed and the second switch is open, the low-voltage voltage regulator performs a step-up process on the input voltage to obtain an output voltage, wherein, a ratio between the input voltage and the output voltage is equal to a ratio between the number of turns of the common winding and a first target number, and the first target number is a sum of the number of turns of the common winding and the number of turns of the series winding.

2. The low-voltage voltage regulator according to claim 1, characterized in that, when the first switch is open and the second switch is closed, the input voltage of the low-voltage voltage regulator is equal to the output voltage of the low-voltage voltage regulator.

3. The low-voltage voltage regulator according to claim 1, characterized in that, the voltage regulating switch further includes: a third switch, a moving contact of the third switch is respectively connected to the second voltage output terminal L' and the second switch, and a stationary contact of the third switch is used to be connected to any one tap of the series winding or a second end of the series winding.

4. The low-voltage voltage regulator according to claim 3, characterized in that, when the first switch is open and the second switch is closed, the input voltage of the low-voltage voltage regulator is equal to the output voltage of the low-voltage voltage regulator.

5. The low-voltage voltage regulator according to claim 3, characterized in that, when the first switch is closed and the second switch is open, the low-voltage voltage regulator performs a step-up process on the input voltage to obtain an output voltage, wherein, a ratio between the input voltage and the output voltage is equal to a ratio between the number of turns of the common winding and a second target number, and the second target number is a sum of the number of turns of the common winding and a first current number of turns of the series winding, and the first current number of turns of the series winding is the number of turns between a first end of the series winding and a first target tap, and the first target tap is any one tap of the series winding.

6. The low-voltage voltage regulator according to claim 3, characterized in that, If the first switch is connected to the second target tap of the series winding, and the static contact is connected to the third target tap, then when the first switch is closed and the second switch is open, the low-voltage regulator performs a step-down process on the input voltage to obtain an output voltage, where the second target tap is any tap in the series winding, the third target tap is any tap between the second target tap and the first end of the series winding or the first end of the series winding, and the ratio between the output voltage and the input voltage is the ratio between the third target quantity and the number of turns of the common winding, where the third target quantity is the difference between the number of turns of the common winding and the second current number of turns of the series winding, and the second current number of turns is the number of turns between the second target tap and the third target tap.

7. The low-voltage regulator according to claim 6, characterized in that if the first switch is connected to the second target tap of the series winding, and the static contact is connected to the fourth target tap, then when the first switch is closed and the second switch is open, the low-voltage regulator performs a step-up process on the input voltage to obtain an output voltage, where the fourth target tap is any tap between the second target tap and the second end of the series winding or the second end of the series winding, and the ratio between the output voltage and the input voltage is the ratio between the fourth target quantity and the number of turns of the common winding, where the fourth target quantity is the sum of the number of turns of the common winding and the third current number of turns of the series winding, and the third current number of turns is the number of turns between the second target tap and the fourth target tap.

8. The low-voltage regulator according to claim 1, characterized in that the first switch and the second switch are vacuum switches.

9. The low-voltage regulator according to claim 3, characterized in that the third switch is an air switch or an oil-immersed switch.

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