JP2023045088A - voltage regulator - Google Patents

Abstract

To provide a voltage regulator capable of switching the connection destination of a terminal of a primary winding in a short period of time.SOLUTION: In a voltage regulator 1, multiple secondary windings 32 in multiple series transformers 3u and 3v are arranged in the middle of multiple distribution lines U and V, respectively. Using multiple switch circuits, a switching unit 5 switches a tap, among multiple taps T1, T2, and T3 connected to a single winding 40, to be electrically connected to each of multiple specific terminals in terminals of multiple primary windings 31 of the multiple series transformers 3u and 3v. In the switch circuit, a second semiconductor switch is connected in series to a first semiconductor switch. A first diode and a second diode are connected between both ends of the first semiconductor switch and the second semiconductor switch, respectively. The cathodes or anodes of the first diode and the second diode are connected to each other.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to voltage regulators.

Patent Literature 1 discloses a configuration for adjusting the effective value of AC voltage between two distribution lines. In this configuration, a tapped winding with multiple taps is connected between two distribution lines. The rms value of the ac voltage between two of the multiple taps is adjusted according to the rms value of the ac voltage between the two distribution lines. Two transformers are arranged, each having a primary winding and a secondary winding. Each of the two secondary windings is placed midway between the two distribution lines.

Each terminal of the two primary windings is electrically connected to one of the multiple taps. Therefore, the alternating voltage between the two taps is applied across each of the two primary windings. As a result, the two secondary windings increase or decrease the effective value of the AC voltage between the two distribution lines on the input side, and the AC voltage with the increased or decreased effective value is passed through the two distribution lines on the output side. output. The switch switches connection destinations of two specific terminals among the terminals of the two primary windings. Depending on the two AC voltages applied to the two primary windings, the effective value is raised or lowered. Depending on the two AC voltages applied to the two primary windings, the range of increase or decrease of the effective value is determined.

JP-A-2004-187374

Regarding Patent Document 1, considering the period from the start of switching of the connection destination of a specific terminal to the end of switching, it is preferable that the period required for switching the connection destination is short.

The present disclosure has been made in view of such circumstances, and an object of the present disclosure is to provide a voltage regulator capable of switching connection destinations of specific terminals in a short period of time.

A voltage regulating device according to one aspect of the present disclosure is a voltage regulating device that adjusts the effective value of an AC voltage, and includes one or more tap windings to which a plurality of taps are connected, a primary winding and a secondary a plurality of transformers having windings, and a plurality of identities among terminals of a plurality of primary windings of the plurality of transformers among a plurality of taps connected to the one or more tap windings; a switch for switching taps to which each of the terminals is electrically connected, wherein the effective value of the alternating voltage between two of the plurality of taps connected to the tap windings is equal to that of two of the plurality of distribution lines; each of the plurality of secondary windings of the plurality of transformers is arranged in the middle of the plurality of distribution lines, and the switch is adapted to conduct current or a cutoff state in which the flow of current is cut off. Each switch circuit has a first semiconductor switch and a a second semiconductor switch connected in series; a first diode connected across the first semiconductor switch; and a second diode connected across the second semiconductor switch; The cathodes or anodes of the first diode and the second diode are connected together.

In the above aspect, by switching on the first semiconductor switch and the second semiconductor switch, the state of the switch circuit is switched to the conduction state. By switching off the first semiconductor switch and the second semiconductor switch, the state of the switch circuit is switched to the blocking state. Therefore, compared with the case where a plurality of mechanical relays are used to switch the connection destination of the specific terminal, the switch can switch the connection destination of the specific terminal in a short period of time.

In the voltage regulating device according to one aspect of the present disclosure, the switch has a resistor, and the plurality of switch circuits are connected to each of the plurality of taps connected to the one or the plurality of tap windings. and a series switch circuit connected in series with the resistor, at least two of the plurality of tap switch circuits are connected to each of the plurality of specific terminals, and the resistor and the series switch circuit is connected between two of the plurality of specific terminals.

In the above aspect, for example, after switching the state of the series switch circuit to the conduction state, the state of one tap switch circuit connected to the specific terminal is switched to the cutoff state. After switching the state of the other tap switch circuit connected to the specific terminal to the conduction state, the state of the series switch circuit is switched to the cutoff state. As a result, the connection destination of the specific terminal is switched without breaking the connection between the two specific terminals connected in the series circuit.

In the voltage regulating device according to one aspect of the present disclosure, the switch includes a determination unit that determines whether or not the slope of the AC voltage between two taps connected to one tap winding is 0 degrees. and a switching circuit for switching the states of the plurality of switch circuits to the conductive state or the cut-off state, wherein the switching circuit switches the series switch when the determination unit determines that the inclination is 0 degree. The state of the circuit is switched from the blocking state to the conducting state.

In the above embodiment, each of the primary and secondary windings of the transformer are wrapped around the core. The core is magnetic. When two taps connected to one tap winding are respectively connected to two terminals of the primary winding, and the slope of the AC voltage between the two taps is 0 degrees, the transformer The residual magnetic flux remaining in the core is 0 [Wb]. The switching circuit switches the state of the series switch circuit to the energized state at the timing when the slope of the AC voltage is 0 degree. Therefore, when the switching circuit switches the state of the series switch circuit to the interrupted state, the magnetic flux of the core is less likely to exceed the saturation magnetic flux. As a result, the possibility of excessive current flowing through the primary winding is low.

In the voltage regulator according to one aspect of the present disclosure, the first semiconductor switch and the second semiconductor switch are IGBTs (Insulated Gate Bipolar Transistors), and emitters or collectors of the first semiconductor switch and the second semiconductor switch are mutually The cathodes of the first diode and the second diode are connected to the collectors of the first semiconductor switch and the second semiconductor switch.

In the above aspect, the first semiconductor switch and the second semiconductor switch are IGBTs. For an IGBT, when the state is on, current can flow in the order collector and emitter. However, current does not flow in the order of emitter and collector. The collectors or emitters of the first semiconductor switch and the second semiconductor switch are connected to each other, and the first diode and the second diode are connected across the first semiconductor switch and the second semiconductor switch, respectively. Therefore, when the first semiconductor switch and the second semiconductor switch are on, alternating current flows through the switch circuit.

In the voltage adjustment device according to one aspect of the present disclosure, the first semiconductor switch and the second semiconductor switch are MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), and the sources of the first semiconductor switch and the second semiconductor switch are or the drains are connected together, the first diode being the parasitic diode of the first semiconductor switch and the second diode being the parasitic diode of the second semiconductor switch.

In the above aspect, the first semiconductor switch and the second semiconductor switch are MOSFETs. For a MOSFET, current flows bi-directionally through the drain and source when the state is on. A parasitic diode is connected across each of the first semiconductor switch and the second semiconductor switch. Therefore, even if the first semiconductor switch is off, current can flow through the first diode. Current can flow through the second diode even when the second semiconductor switch is off. The cathodes or anodes of the first diode and the second diode are connected together. Therefore, no current flows through the first diode or the second diode when the first semiconductor switch and the second semiconductor switch are off.

According to the above aspect, the connection destination of the specific terminal can be switched in a short period of time.

1 is a circuit diagram of a voltage regulator according to Embodiment 1; FIG. FIG. 3 is a block diagram showing the configuration of main parts of a switch; FIG. 4 is an explanatory diagram of a decrease in the effective value of AC voltage; Fig. 4 is a diagram showing the action of two series transformers; 4 is a circuit diagram of a first switch circuit; FIG. 4 is a timing chart showing outputs of an output transformer, differentiating circuit and detecting circuit; 4 is a flow chart showing a procedure of switching processing; FIG. 10 is a circuit diagram of a voltage regulator according to Embodiment 2; FIG. 3 is a block diagram showing the configuration of main parts of a switch; FIG. 10 is a circuit diagram of a voltage regulator according to Embodiment 3; FIG. 3 is a block diagram showing the configuration of main parts of a switch;

Hereinafter, the present invention will be described in detail based on the drawings showing its embodiments.
(Embodiment 1)
FIG. 1 is a circuit diagram of a voltage regulator 1 according to Embodiment 1. FIG. An AC power supply 2 is connected between two distribution lines U and V. The AC power supply 2 is, for example, a substation. The AC power supply 2 outputs an AC voltage to the voltage regulator 1 via two distribution lines U and V. As shown in FIG. The voltage regulating device 1 outputs an alternating voltage via two distribution lines U, V and a neutral line Q. The voltage regulator 1 adjusts the effective value of the AC voltage between the distribution lines U and V on the output side according to the effective value of the AC voltage between the distribution lines U and V on the input side. The effective value of the AC voltage between the distribution line U and the neutral wire Q and the effective value of the AC voltage between the distribution line V and the neutral wire Q are the effective values of the AC voltage between the distribution lines U and V on the output side. is one-half of

The voltage regulating device 1 comprises two series transformers 3u, 3v, a regulating transformer 4, a switch 5 and a measuring transformer 6. Series transformers 3 u and 3 v each have an annular core 30 , primary winding 31 and secondary winding 32 . Core 30 is a magnetic material. A primary winding 31 and a secondary winding 32 are each wound around the core 30 . Regulating transformer 4 has a single winding 40 . A single winding 40 is wound around a core (not shown). The single winding 40 is connected to three taps T1, T2, T3. Two terminals of the single winding 40 are connected to taps T1 and T3, respectively. A tap T2 and one terminal of the neutral wire Q are connected in the middle of the single winding 40 . The measuring transformer 6 has a primary winding 61 and a secondary winding 62 . Primary winding 61 and secondary winding 62 are wound on a common core.

Secondary windings 32 of series transformers 3u and 3v are arranged in the middle of distribution lines U and V, respectively. Input-side distribution lines U and V are connected to one terminal of the secondary winding 32 of each of the series transformers 3u and 3v. Output-side distribution lines U and V are connected to the other terminals of the secondary windings 32 of the series transformers 3u and 3v, respectively. A single winding 40 is connected between distribution lines U and V on the output side. The taps T1 and T3 are located on the distribution lines U and V sides, respectively. The switch 5 is connected to three taps T1, T2, T3. Regarding the single winding 40, the number of turns from one terminal to the neutral wire Q is the same as the number of turns from the other terminal to the neutral wire Q.

The first and second terminals of the primary winding 31 of the series transformer 3u are connected to the first and second terminals of the primary winding 31 of the series transformer 3v, respectively. A connection node between two first terminals is hereinafter referred to as a first node. A connection node between two second terminals is referred to as a second node. The switch 5 is further connected to the first node and the second node. In FIG. 1, the first node and the second node are located on the right and left sides, respectively. A primary winding 61 of the measuring transformer 6 is connected between the distribution lines U and V on the output side. Two terminals of the secondary winding 62 are connected to the switch 5 .

Each of the first and second nodes is electrically connected to one of the three taps T1, T2, T3. Each of the first terminal and the second terminal of one primary winding 31 functions as a specific terminal. The switch 5 switches the taps to which the first node and the second node are electrically connected among the three taps T1, T2 and T3, that is, the connection destinations of the first node and the second node. The rms value of the ac voltage between two of the three taps T1, T2, T3 is adjusted according to the rms value of the ac voltage across the distribution lines U, V on the output side. When the first node and the second node are respectively connected to two mutually different taps, the AC voltage between the two connected taps is applied to both ends. A single winding 40 functions as a tap winding.

The effective value of the AC voltage between the two taps of the single winding 40 is represented by the product of the effective value of the AC voltage between the distribution lines U and V on the output side and the turns ratio of the single winding 40 . The turns ratio of the single winding 40 is (the number of turns between the two taps)/(the number of turns of the single winding 40). The greater the number of turns between the two taps, the greater the effective value of the AC voltage between the two taps.

The secondary windings 32 of the series transformers 3u and 3v convert the effective value of the AC voltage between the distribution lines U and V on the output side to the effective value of the AC voltage between the distribution lines U and V on the input side and the single-turn voltage. Line 40 adjusts according to the AC voltage output from the two taps. The AC voltage output by the single winding 40 changes according to the connection destinations of the first node and the second node. If the connection destinations of the first node and the second node are the same, the single winding 40 will not output AC voltage from the two taps.

An AC voltage between distribution lines U and V on the output side is applied to both ends of the primary winding 61 of the measuring transformer 6 . Secondary winding 62 outputs an AC voltage to switch 5 . The effective value of the AC voltage output by the secondary winding 62 is determined by the product of the effective value of the AC voltage between the distribution lines U and V on the output side and the turns ratio of the primary winding 61 and the secondary winding 62. expressed. The turns ratio is (the number of turns of the secondary winding 62)/(the number of turns of the primary winding 61). The turns ratio is a constant value. Therefore, the effective value of the AC voltage output by the secondary winding 62 indicates the effective value of the AC voltage between the distribution lines U and V on the output side.

The switch 5 switches connection destinations of the first node and the second node according to the effective value of the AC voltage between the distribution lines U and V on the output side. As a result, the effective value of the AC voltage between the distribution lines U and V on the output side is adjusted to a value within a predetermined allowable range. Note that the effective value of the AC voltage input from the AC power supply 2 to the voltage regulator 1 fluctuates. In this case, the effective value of the AC voltage between the distribution lines U and V on the output side also fluctuates. Therefore, it is necessary to adjust the effective value of the AC voltage between the distribution lines U and V on the output side.

FIG. 2 is a block diagram showing the main configuration of the switch 5. As shown in FIG. The switch 5 has an aggregate 50 , a series switch circuit 51 and a resistor 52 . The aggregate 50 has three first switch circuits A1, A2, A3 and three second switch circuits B1, B2, B3. Any integer among 1, 2 and 3 is described as i below. The integer i can be any of 1, 2 and 3. Each of the first switch circuit Ai and the second switch circuit Bi is connected to the tap Ti and functions as a tap switch circuit.

Each of the three first switch circuits A1, A2, A3 is also connected to the first node. Each of the three second switch circuits B1, B2, B3 is also connected to a second node. A series switch circuit 51 is connected in series with a resistor 52 . A series circuit including a series switch circuit 51 and a resistor 52 is connected between the first node and the second node.

The switch 5 further has a control section 53 and a switching circuit 54 . The controller 53 is connected to the switching circuit 54 . The states of the series switch circuit 51, the first switch circuit Ai, and the second switch circuit Bi include a conducting state in which current can flow and an interrupted state in which current does not flow. The control unit 53 instructs the switching circuit 54 to switch the state of each of the series switch circuit 51, the first switch circuits A1, A2, A3, and the second switch circuits B1, B2, B3 to the conducting state or the blocking state. .

When only the first switch circuit A1 and the second switch circuit B3 among the series switch circuit 51, the first switch circuits A1, A2, A3, and the second switch circuits B1, B2, B3 are in the conductive state, The secondary windings 32 of the two series transformers 3u and 3v make the effective value of the AC voltage between the distribution lines U and V on the output side higher than the effective value of the AC voltage between the distribution lines U and V on the input side. Raise to a higher value.

The voltage of the distribution line U whose reference potential is the potential of the distribution line V is described as Vs. In FIG. 2, when only the states of the first switch circuit A1 and the second switch circuit B3 are in the conductive state, the direction of current flowing when the polarity of the voltage Vs is positive is indicated by dashed arrows. there is Current flows through the tap T1, the first switch circuit A1, and the first node in this order. In each of the two primary windings 31, current flows through the first node and the second node in that order. Current flows through the second node, the second switch circuit B3 and the tap T3 in this order.

In each of the series transformers 3u and 3v, an induced electromotive force is generated in the secondary winding 32 when a current flows through the primary winding 31. FIG. Since a common AC voltage is applied across each of the two primary windings 31, the voltages of the two induced electromotive forces are the same. In FIG. 2, the voltage polarities of the two induced electromotive forces are shown. The absolute value of the voltage of the induced electromotive force is described as ΔV.

When a current flows from the first node to the second node in the primary winding 31 of the series transformer 3u, the secondary winding 32 changes the potential of the distribution line U on the output side to that of the distribution line U on the input side. The potential is adjusted to ΔV higher than the potential. When a current flows from the first node to the second node in the primary winding 31 of the series transformer 3v, the secondary winding 32 changes the potential of the distribution line V on the output side to that of the distribution line U on the input side. The potential is adjusted to be ΔV lower than the potential. Therefore, when the polarity of the voltage Vs is positive, the voltage between the distribution lines U and V on the output side is regulated to (Vs+(2·ΔV)), which is higher than the voltage Vs. "·" represents a product.

When only the states of the first switch circuit A1 and the second switch circuit B3 are in the conducting state, the direction of the current shown in FIG. 2 is reversed when the polarity of the voltage Vs is negative. The polarities of the voltages of the two induced electromotive forces are also reversed. Current flows through the tap T3, the second switch circuit B3 and the second node in this order. In each of the two primary windings 31, current flows through the second node and the first node in that order. Current flows through the first node, the first switch circuit A1 and the tap T1 in this order.

When a current flows from the second node to the first node in the primary winding 31 of the series transformer 3u, the secondary winding 32 changes the potential of the distribution line U on the output side to that of the distribution line U on the input side. The potential is adjusted to be ΔV lower than the potential. When a current flows from the second node to the first node in the primary winding 31 of the series transformer 3v, the secondary winding 32 changes the potential of the distribution line V on the output side to that of the distribution line U on the input side. The potential is adjusted to ΔV higher than the potential. Therefore, when the polarity of the voltage Vs is negative, the voltage between the distribution lines U and V on the output side is regulated to (Vs-(2·ΔV)), which is lower than the voltage Vs.

From the above, when only the states of the first switch circuit A1 and the second switch circuit B3 are in the conductive state, the effective value (amplitude) of the AC voltage between the distribution lines U and V on the output side is It is adjusted to a value higher than the effective value (amplitude) of the AC voltage between the distribution lines U and V.

Among the series switch circuit 51, the first switch circuits A1, A2, A3, and the second switch circuits B1, B2, B3, if only the first switch circuit A3 and the second switch circuit B1 are in the conduction state, The secondary windings 32 of the two series transformers 3u and 3v make the effective value of the AC voltage between the distribution lines U and V on the output side higher than the effective value of the AC voltage between the distribution lines U and V on the input side. Decrease to a lower value.

FIG. 3 is an explanatory diagram of a decrease in the effective value of AC voltage. In FIG. 3, when only the first switch circuit A3 and the second switch circuit B1 are in the conducting state, the direction of current flowing when the polarity of the voltage Vs is positive is indicated by the dashed arrow. there is The voltage polarities of the two induced EMFs are also shown. When only the states of the first switch circuit A3 and the second switch circuit B1 are in the conductive state, the current flows through the tap T1, the second switch circuit B1 and the second node in this order. In each of the two primary windings 31, current flows through the second node and the first node in that order. Current flows through the first node, the first switch circuit A3 and the tap T3 in this order.

In each of the two primary windings 31 current flows from the first node to the second node. Therefore, when the polarity of the voltage Vs is positive, the two secondary windings 32 adjust the voltage between the distribution lines U and V on the output side to (Vs-(2·ΔV)). The voltage between the distribution lines U, V on the output side is lower than the voltage Vs.

When only the states of the first switch circuit A3 and the second switch circuit B1 are conductive, the direction of the current shown in FIG. 2 is reversed when the polarity of the voltage Vs is negative. The polarities of the voltages of the two induced electromotive forces are also reversed. Current flows through the tap T3, the first switch circuit A3 and the first node in this order. In each of the two primary windings 31, current flows through the first node and the second node in that order. Current flows through the second node, the second switch circuit B1 and the tap T1 in this order.

In each of the two primary windings 31 current flows from the second node to the first node. Therefore, when the polarity of the voltage Vs is negative, the two secondary windings 32 regulate the voltage between the distribution lines U and V on the output side to (Vs+(2·ΔV)). The voltage between the distribution lines U, V on the output side is higher than the voltage Vs.

From the above, when only the states of the first switch circuit A3 and the second switch circuit B1 are in the conductive state, the effective value of the AC voltage between the output side distribution lines U and V is the input side distribution line U , V is adjusted to a value lower than the rms value of the alternating voltage between .

FIG. 4 is a diagram showing the action of the two series transformers 3u, 3v. FIG. 4 shows the relationship between the combination of the first switch circuit and the second switch circuit in the conducting state and the action of the two secondary windings 32 of the two series transformers 3u, 3v. As described above, when only the states of the first switch circuit A1 and the second switch circuit B3 are in the conductive state, the two secondary windings 32 are connected to the effective AC voltage between the distribution lines U and V on the input side. raise the value.

When only the first switch circuit A2 and the second switch circuit B3 are in the conductive state, or when only the first switch circuit A1 and the second switch circuit B2 are in the conductive state, the current direction is , is the same as the direction of the current when only the states of the first switch circuit A1 and the second switch circuit B3 are in the conduction state. Therefore, the two secondary windings 32 raise the effective value of the AC voltage between the distribution lines U and V on the input side.

The increase in the effective value increases as the effective value of the AC voltage applied across each of the two primary windings 31 increases. For the single winding 40, the number of turns between taps T1 and T3 is greater than the number of turns between taps T2 and T3. Therefore, the effective value of the alternating voltage between the taps T1 and T3 is larger than the effective value of the alternating voltage between the taps T2 and T3. For the single winding 40, the number of turns between taps T2 and T3 is greater than the number of turns between taps T1 and T2. Therefore, the effective value of the AC voltage between the taps T2 and T3 is larger than the effective value of the AC voltage between the taps T1 and T2.

When only the states of the first switch circuit Ai and the second switch circuit Bi are in the conductive state, the connection destinations of the first node and the second node are the same. Therefore, the single winding 40 does not output AC voltage toward the two primary windings 31 . The effective value of the alternating voltage between the distribution lines U and V on the output side is substantially the same as the effective value of the alternating voltage between the distribution lines U and V on the input side. The integer i is any integer among 1, 2 and 3.

As described above, when only the states of the first switch circuit A3 and the second switch circuit B1 are in the conductive state, the two secondary windings 32 are connected to the effective AC voltage between the distribution lines U and V on the input side. Decrease value. When only the first switch circuit A3 and the second switch circuit B2 are in the conductive state, or when only the first switch circuit A2 and the second switch circuit B1 are in the conductive state, the current direction is , the direction of current flow when only the first switch circuit A3 and the second switch circuit B1 are in the conducting state. Therefore, the two secondary windings 32 reduce the effective value of the alternating voltage between the distribution lines U and V on the input side.

The larger the effective value of the AC voltage applied across each of the two primary windings 31, the larger the reduction in the effective value of the AC voltage between the distribution lines U and V on the output side. As described above, the effective value of AC voltage between taps T1 and T3 is greater than the effective value of AC voltage between taps T2 and T3.
The effective value of AC voltage between taps T2 and T3 is greater than the effective value of AC voltage between taps T1 and T2.

As shown in FIG. 2, two terminals of the secondary winding 62 of the measuring transformer 6 are connected to the control section 53 of the switch 5 . As described above, the effective value of the AC voltage output by the secondary winding 62 indicates the effective value of the AC voltage between the distribution lines U and V on the output side. The control unit 53 switches the first switch circuits A1, A2, A3 and the second switch circuits B1, B2, B3 in the conductive state according to the effective value of the AC voltage between the distribution lines U, V on the output side. To switch a certain switch circuit. By performing this switching, the control unit 53 adjusts the effective value of the AC voltage between the distribution lines U and V on the output side to a value within a predetermined allowable range.

FIG. 5 is a circuit diagram of the first switch circuit A1. The configurations of the series switch circuit 51, the first switch circuits A2, A3, and the second switch circuits B1, B2, B3 are the same as the configuration of the first switch circuit A1. Therefore, description of these configurations is omitted. The first switch circuit A1 has a first semiconductor switch G1, a second semiconductor switch G2, a first diode D1 and a second diode D2. FIG. 5 shows four examples of the first switch circuit A1. The types of the first semiconductor switch G1 and the second semiconductor switch G2 are the same. The second semiconductor switch G2 is connected in series with the first semiconductor switch G1.

In the first example of the first switch circuit A1, the first semiconductor switch G1 and the second semiconductor switch G2 are IGBTs (Insulated Gate Bipolar Transistors). The emitter of the first semiconductor switch G1 is connected to the emitter of the second semiconductor switch G2. The cathode and anode of the first diode D1 are respectively connected to the collector and emitter of the first semiconductor switch G1. The cathode and anode of the second diode D2 are respectively connected to the collector and emitter of the second semiconductor switch G2. Accordingly, the anode of the first diode D1 is connected to the anode of the second diode D2. Gates of the first semiconductor switch G1 and the second semiconductor switch G2 are connected to the switching circuit 54 . Each collector of the first semiconductor switch G1 and the second semiconductor switch G2 is connected to the first node and the tap T1.

The switching circuit 54 switches the first semiconductor switch G1 and the second semiconductor switch G2 on or off by adjusting the voltages of the two gates whose reference potential is the ground potential. When the switching circuit 54 raises the voltage of the two gates, the first semiconductor switch G1 and the second semiconductor switch G2 are switched on. For each of the first semiconductor switch G1 and the second semiconductor switch G2, when the state is on, current can flow through the collector and the emitter in that order. In each of the first semiconductor switch G1 and the second semiconductor switch G2, current does not flow through the emitter and collector in that order.

When the first semiconductor switch G1 and the second semiconductor switch G2 are on, the state of the first switch circuit A1 is the conductive state. The current input to the collector of the first semiconductor switch G1 flows through the first semiconductor switch G1 and the second diode D2 in that order, as indicated by the solid arrow. The current input to the collector of the second semiconductor switch G2 flows through the second semiconductor switch G2 and the first diode D1 in that order, as indicated by the dashed arrow. An alternating current flows through the first switch circuit A1.

When the switching circuit 54 reduces the voltage on the two gates, the first semiconductor switch G1 and the second semiconductor switch G2 are switched off. For each of the first semiconductor switch G1 and the second semiconductor switch G2, no current flows through the collector and emitter when the state is off. When the first semiconductor switch G1 and the second semiconductor switch G2 are off, the state of the first switch circuit A1 is the blocking state. No current flows through the collectors of the first semiconductor switch G1 and the second semiconductor switch G2.

In a second example of the first switch circuit A1, the first semiconductor switch G1 and the second semiconductor switch G2 are IGBTs. The collector of the first semiconductor switch G1 is connected to the collector of the second semiconductor switch G2. The first diode D1 and the second diode D2 are connected in the same manner as in the first example. Accordingly, the cathode of the first diode D1 is connected to the cathode of the second diode D2. Gates of the first semiconductor switch G1 and the second semiconductor switch G2 are connected to the switching circuit 54 . The respective emitters of the first semiconductor switch G1 and the second semiconductor switch G2 are connected to the tap T1 and the first node.

When the switching circuit 54 switches on the first semiconductor switch G1 and the second semiconductor switch G2, the state of the first switching circuit A1 switches to the conductive state. The current input to the emitter of the second semiconductor switch G2 flows through the second diode D2 and the first semiconductor switch G1 in that order, as indicated by the solid arrow. The current input to the emitter of the first semiconductor switch G1 flows through the first diode D1 and the second semiconductor switch G2 in that order, as indicated by the dashed arrow. An alternating current flows through the first switch circuit A1.

When the switching circuit 54 switches off the first semiconductor switch G1 and the second semiconductor switch G2, the state of the first switching circuit A1 switches to the blocking state. No current flows through the emitters of the first semiconductor switch G1 and the second semiconductor switch G2.

In the third example of the first switch circuit A1, the first semiconductor switch G1 and the second semiconductor switch G2 are N-channel MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). The source of the first semiconductor switch G1 is connected to the source of the second semiconductor switch G2. The first diode D1 is a parasitic diode of the first semiconductor switch G1. The cathode and anode of the first diode D1 are connected to the drain and source of the first semiconductor switch G1, respectively.

Similarly, the second diode D2 is a parasitic diode of the second semiconductor switch G2. The cathode and anode of the second diode D2 are respectively connected to the drain and source of the second semiconductor switch G2. Accordingly, the anode of the first diode D1 is connected to the anode of the second diode D2. Gates of the first semiconductor switch G1 and the second semiconductor switch G2 are connected to the switching circuit 54 . The drains of the first semiconductor switch G1 and the second semiconductor switch G2 are connected to the first node and the tap T1.

The switching circuit 54 switches the first semiconductor switch G1 and the second semiconductor switch G2 on or off as in the first example. For each of the first semiconductor switch G1 and the second semiconductor switch G2, when the state is on, current can flow bi-directionally via the drain and the source. When the first semiconductor switch G1 and the second semiconductor switch G2 are on, the state of the first switch circuit A1 is the conducting state. In this state, current flows bidirectionally through the first semiconductor switch G1 and the second semiconductor switch G2, as indicated by the solid and dashed arrows. No current flows through the first diode D1 or the second diode D2.

When the first semiconductor switch G1 and the second semiconductor switch G2 are off, the state of the first switch circuit A1 is the blocking state. In this state, no current flows through the drains of the first semiconductor switch G1 and the second semiconductor switch G2.

As described above, the first diode D1 (parasitic diode) is connected between the drain and source of the first semiconductor switch G1. Therefore, even when the first semiconductor switch G1 is off, current can flow through the first diode D1. As described above, the second diode D2 (parasitic diode) is connected between the drain and source of the second semiconductor switch G2. Therefore, even when the second semiconductor switch G2 is off, current can flow through the second diode D2. However, in the first switch circuit A1, the anodes of the first diode D1 and the second diode D2 are connected to each other. Therefore, when the first semiconductor switch G1 and the second semiconductor switch G2 are off, no current flows through the first diode D1 or the second diode D2.

In the fourth example of the first switch circuit A1, the first semiconductor switch G1 and the second semiconductor switch G2 are N-channel MOSFETs. The drain of the first semiconductor switch G1 is connected to the drain of the second semiconductor switch G2. The first diode D1 and the second diode D2 are parasitic diodes of the first semiconductor switch G1 and the second semiconductor switch G2, respectively. The first diode D1 and the second diode D2 are connected in the same manner as in the third example. Accordingly, the cathode of the first diode D1 is connected to the cathode of the second diode D2. Gates of the first semiconductor switch G1 and the second semiconductor switch G2 are connected to the switching circuit 54 . Sources of the first semiconductor switch G1 and the second semiconductor switch G2 are connected to the tap T1 and the first node.

When the switching circuit 54 switches on the first semiconductor switch G1 and the second semiconductor switch G2, the state of the first switching circuit A1 switches to the conducting state. In this case, current flows in both directions through the first semiconductor switch G1 and the second semiconductor switch G2, as indicated by the solid line and broken line arrows. No current flows through the first diode D1 or the second diode D2. When the switching circuit 54 switches off the first semiconductor switch G1 and the second semiconductor switch G2, the state of the first switching circuit A1 switches to the blocking state. In this case, no current flows through the sources of the first semiconductor switch G1 and the second semiconductor switch G2. Since the cathodes of the first diode D1 and the second diode D2 are connected together, no current flows through the first diode D1 or the second diode D2.

In each of the third and fourth examples of the first switch circuit A1, the first semiconductor switch G1 and the second semiconductor switch G2 may be P-channel MOSFETs. In this case, the cathode and anode of the first diode D1 are connected to the source and drain of the first semiconductor switch G1. Similarly, the cathode and anode of the second diode D2 are connected to the source and drain of the second semiconductor switch G2. The switching circuit 54 turns on the first semiconductor switch G1 and the second semiconductor switch by lowering the voltage on the gate. The switching circuit 54 switches off the first semiconductor switch G1 and the second semiconductor switch by increasing the voltage on the gate.

Regarding the first and second examples, the first semiconductor switch G1 and the second semiconductor switch G2, respectively, may be bipolar transistors different from IGBTs. For example, instead of IGBTs, bipolar transistors having collectors, emitters and bases may be used. In this case the base corresponds to the gate. Regarding the third example and the fourth example, each of the first semiconductor switch G1 and the second semiconductor switch G2 may be an FET other than a MOSFET.

One or both connection destinations of the switch circuit different from the first switch circuit A1 are different from one or both connection destinations of the first switch circuit A1. As described above, the second switch circuit B2 is connected to the tap T2 and the second node. A series switch circuit 51 is connected between a first node or second node and a resistor 52 .

The switch 5 further comprises an output transformer 55, a differentiation circuit 56 and a detection circuit 57, as shown in FIG. The output transformer 55 has a primary winding 55f and a secondary winding 55r. The primary winding 55f and the secondary winding 55r are wound around, for example, an annular core. Two terminals of the primary winding 55f are connected to taps T1 and T2, respectively. Two terminals of the secondary winding 55r are connected to the differentiating circuit 56, respectively. Differentiation circuit 56 is further connected to detection circuit 57 . The detection circuit 57 is also connected to the control section 53 .

FIG. 6 is a timing chart showing the outputs of the output transformer 55, differentiation circuit 56 and detection circuit 57. In FIG. Voltage and time are shown on the vertical and horizontal axes of each output, respectively. The output of the output transformer 55 is the alternating voltage that the secondary winding 55r outputs to the differentiating circuit 56. FIG. The phase of the AC voltage output by the secondary winding 55r matches the phase of the AC voltage applied across the primary winding 55f, that is, the phase of the AC voltage across the taps T1 and T2 of the single winding 40. there is When the output of output transformer 55 is compared with the AC voltage across taps T1 and T2, only the effective value differs. In the example of FIG. 6, the effective value (amplitude) of the AC voltage is stable.

The phase of the AC voltage between the taps T1, T2 matches the phase of the AC voltage between any two taps among the taps T1, T2, T3. Therefore, the taps to which the two terminals of the primary winding 55f of the output transformer 55 are connected are not limited to the taps T1 and T2. For example, two terminals of the primary winding 55f may be connected to taps T2 and T3, respectively. In the following description, the AC voltage output from the two taps connected to the single winding 40 toward the switch 5 is referred to as the output of the single winding 40 .

Differentiation circuit 56 outputs a voltage proportional to the output of output transformer 55 , ie, the output of single winding 40 . Therefore, when the slope of the output of the single winding 40 is 0 degrees, the output of the differentiating circuit 56 is 0 [V]. The detection circuit 57 outputs a high level voltage or a low level voltage to the control section 53 . The detection circuit 57 switches the output voltage to a high level voltage or a low level voltage each time the output of the differentiating circuit 56 becomes 0 [V]. The switching from the low level voltage to the high level voltage and the switching from the high level voltage to the low level voltage indicate that the output slope of the single winding 40 is 0 degrees.

The control unit 53 is, for example, a microcomputer. The control unit 53 has a processing element that executes processing, such as a CPU (Central Processing Unit). A computer program is stored in the controller 53 . The processing element of the control unit 53 performs switching processing for switching connection destinations of the first node and the second node by executing a computer program.

FIG. 7 is a flowchart showing the procedure of switching processing. In the switching process, the control unit 53 first determines whether to switch the connection destination of both or one of the first node and the second node based on the effective value of the AC voltage between the distribution lines U and V on the output side. Determine (step S1). When the control unit 53 determines not to change the connection destination (S1: NO), the control unit 53 executes step S1 again and waits until the timing of switching the connection destination arrives.

When determining to switch the connection destination (S1: YES), the control unit 53 determines whether or not the inclination of the output of the single winding 40 is 0 degree based on the output voltage of the detection circuit 57 (step S2). The control section 53 functions as a determination section. When the controller 53 determines that the inclination is not 0 degrees (S2: NO), it executes step S2 again and waits until the inclination of the output of the single winding 40 becomes 0 degrees.

When the control unit 53 determines that the inclination is 0 degrees (S2: YES), it instructs the switching circuit 54 to switch the state of the series switch circuit 51 from the blocking state to the conducting state (step S3). Next, the controller 53 instructs the switching circuit 54 to switch between the first switching circuits A1, A2, A3 and the second switching circuits B1, B2, B3 which are in the conductive state. The state of the switch circuit is switched to the cut-off state (step S4).

Immediately after the control unit 53 executes step S4, all the first switch circuits A1, A2, A3 and all the second switch circuits B1, B2, B3 are in the cut-off state. However, since the state of the series switch circuit 51 is the conductive state, the connection between the first node and the second node is not interrupted.

After executing step S4, the control unit 53 switches the states of the three first switch circuits A1, A2, A3 and the three second switch circuits B1, B2, B3 to the conduction state. and select the second switch circuit (step S5). Next, the control unit 53 instructs the switching circuit 54 to switch the state of the first switch circuit and the second switch circuit selected in step S5 from the blocking state to the conducting state (step S6). Next, the controller 53 instructs the switching circuit 54 to switch the state of the series switch circuit 51 from the conducting state to the blocking state (step S7).

As a result, among the taps T1, T2, and T3, the taps to which the first node and the second node are connected are switched. As a result, the AC voltage applied across the primary windings 31 of the series transformers 3u and 3v is changed, and the effective value of the AC voltage between the distribution lines U and V on the output side is changed. After executing step S7, the control unit 53 executes the switching process again.

As described above, in each of the series switch circuit 51, the first switch circuits A1, A2, A3, and the second switch circuits B1, B2, B3 of the voltage regulator 1, the switch circuit 54 includes the first semiconductor switch G1 and the second switch circuit G1. By switching the semiconductor switch G2 on or off, the state is switched between the conducting state and the blocking state. Therefore, the switch 5 can switch the connection destinations of the first node and the second node in a short period of time, compared to the case where a plurality of mechanical relays are used to switch the connection destinations of the first node and the second node. can. Therefore, the power consumed in the switch 5 is small.

After switching the state of the series switch circuit 51 to the conduction state, the switching circuit 54 switches the states of the first switch circuit and the second switch circuit connected to the first node and the second node, respectively, to the cutoff state. After switching the states of the first switch circuit and the second switch circuit to the conductive state, the switching circuit 54 switches the state of the series switch circuit 51 to the cutoff state. As a result, the connection destination of at least one of the first node and the second node is switched without disconnecting the connection between the first node and the second node. Since the connection between the first node and the second node is not interrupted, the voltage between the first node and the second node can thus rise to an abnormally high voltage due to the induced electromotive force in the two primary windings 31. sex is low.

In each of the series transformers 3u and 3v, when the gradient of the AC voltage applied across the primary winding 31 from the single winding 40 is 0 degrees, the residual magnetic flux remaining in the core 30 is 0 [Wb]. is. The switching circuit 54 switches the state of the series switch circuit 51 from the cut-off state to the energized state at the timing when the inclination of the output of the single winding 40 is 0 degrees. Therefore, when the switching circuit 54 switches the state of the series switch circuit 51 from the conducting state to the blocking state, the magnetic fluxes of the cores 30 of the series transformers 3u and 3v change from 0 [Wb]. Therefore, in each of the series transformers 3u and 3v, the possibility that the magnetic flux of the core 30 exceeds the saturation magnetic flux is low.

While the core 30 flux exceeds the saturation flux, the impedance of the two primary windings 31 is significantly lower. As a result, excessive current flows through each of the two primary windings 31 . In the voltage regulator 1, as described above, the magnetic flux of each of the two cores 30 is less likely to exceed the saturation magnetic flux. Therefore, the possibility of excessive current flowing through the primary winding 31 is low.

Note that if the period from when the switching circuit 54 switches the state of the series switch circuit 51 from the cut-off state to the conducting state to when the switching circuit 54 returns the state of the series switch circuit 51 to the cut-off state is short, the magnetic flux of the core 30 is less likely to exceed the saturation flux. Therefore, if this period is short, the control unit 53 may omit the execution of step S3 of the switching process. In this case, the switcher 5 does not need to have the output transformer 55, the differentiating circuit 56 and the detecting circuit 57. FIG.

(Embodiment 2)
In Embodiment 1, the number of distribution lines is two. However, the number of distribution lines is not limited to two, and may be three.
In the following, the points of the second embodiment that differ from the first embodiment will be described. Other configurations except those described later are the same as in Embodiment 1. Therefore, components common to Embodiment 1 are given the same reference numerals as those in Embodiment 1, and descriptions thereof are omitted. do.

FIG. 8 is a circuit diagram of voltage regulator 1 according to the second embodiment. In Embodiment 2, in addition to the distribution lines U and V, a distribution line W is connected to the AC power supply 2 . The AC power supply 2 outputs three AC voltages to the voltage regulator 1 via the three distribution lines U, V, W. The three AC voltages are an AC voltage between the distribution lines U and V, an AC voltage between the distribution lines V and W, and an AC voltage between the distribution lines U and W. The effective values of the three AC voltages are substantially the same. The phase of the first AC voltage is 120 degrees out of phase with respect to the phase of the second AC voltage. The phase of the second AC voltage is 120 degrees out of phase with respect to the phase of the third AC voltage.

The voltage regulator 1 has a series transformer 3w in addition to the two series transformers 3u and 3v. The series transformer 3w is configured similarly to the series transformer 3u. A secondary winding 32 of the series transformer 3w is arranged in the middle of the distribution line W. The AC power supply 2 and one terminal of the secondary winding 32 of the series transformer 3w are connected by a distribution line W on the input side. The other terminal of the secondary winding 32 of the series transformer 3w is connected to the distribution line W on the output side. The secondary windings 32 of the three series transformers 3u, 3v, 3w regulate the effective values of the three AC voltages on the distribution lines U, V, W on the output side. When the effective values of the three AC voltages of the distribution lines U, V, W on the input side change, the effective values of the three AC voltages of the distribution lines U, V, W on the output side also change.

The voltage regulation device 1 further comprises two regulation transformers 4a, 4b. Each regulating transformer 4 a , 4 b has a primary winding 41 and a secondary winding 42 . Each of the primary winding 41 and secondary winding 42 is wound around, for example, an annular core. A primary winding 41 of the regulating transformer 4a is connected between the distribution lines U and V. As shown in FIG. A primary winding 41 of the regulating transformer 4b is connected between the distribution lines V and W. The connection of the two primary windings 41 is V-connection. Three taps T1, T2, T3 are connected to each secondary winding 42 of each of the regulating transformers 4a, 4b. Each secondary winding 42 functions as a tap winding.

AC voltages are output from two taps connected to the secondary winding 42 of each of the regulating transformers 4a and 4b. The effective value of this AC voltage is represented by the product of the effective value of the AC voltage applied across the primary winding 41 and the turns ratio. Here, the turns ratio is represented by (the number of turns between two taps)/(the number of turns of the primary winding 41). Therefore, the greater the number of turns between the two taps, the greater the effective value of the AC voltage between the two taps. An AC voltage between distribution lines U and V on the output side is applied to both ends of the primary winding 41 of the regulating transformer 4a. An AC voltage between the distribution lines V and W on the output side is applied to both ends of the primary winding 41 of the regulating transformer 4b. The phase of the AC voltage between the taps T1, T2 matches the phase of the AC voltage between any two taps among the taps T1, T2, T3.

The voltage regulator 1 has three measuring transformers 6a, 6b configured similarly to the measuring transformer 6 of the first embodiment. A primary winding 61 of the measuring transformer 6a is connected between the distribution lines U,V. A primary winding 61 of the measuring transformer 6b is connected between the distribution lines V and W. A secondary winding 62 of the measuring transformer 6a outputs an alternating voltage whose effective value is proportional to the effective value of the alternating voltage between the distribution lines U,V. A secondary winding 62 of the measuring transformer 6b outputs an alternating voltage whose effective value is proportional to the effective value of the alternating voltage between the distribution lines V,W.

FIG. 9 is a block diagram showing the essential configuration of the switch 5. As shown in FIG. The switch 5 has two aggregates 50a, 50b which are configured similarly to the aggregate 50 of the first embodiment. The assembly 50a, like the assembly 50 of the first embodiment, is connected to three taps T1, T2, T3 connected to the secondary winding 42 of the regulating transformer 4a. The assembly 50b, like the assembly 50 of the first embodiment, is connected to three taps T1, T2, T3 connected to the secondary winding 42 of the regulating transformer 4b.

One terminal of the three primary windings 31 functions as a specific terminal. A specific terminal of the primary winding 31 of the series transformer 3u is connected to the first switch circuits A1, A2, A3 of the assembly 50a. A specific terminal of the primary winding 31 of the series transformer 3v is connected to the second switch circuits B1, B2, B3 of the assembly 50a and the first switch circuits A1, A2, A3 of the assembly 50b. A specific terminal of the primary winding 31 of the series transformer 3w is connected to the second switch circuits B1, B2, B3 of the assembly 50b. The other terminal of one primary winding 31 is connected to the other terminals of the remaining two primary windings. The connection of the three primary windings 31 is Y-connection.

The switch 5 further comprises two series switch circuits 51a, 51b and two resistors 52a, 52b. Each of the series switch circuits 51a and 51b is configured similarly to the series switch circuit 51 of the first embodiment. The series switch circuit 51a is connected in series with the resistor 52a. This series circuit is connected between specific terminals of the primary windings 31 of the series transformers 3u and 3v. The series switch circuit 51b is connected in series with the resistor 52b. This series circuit is connected between specific terminals of the primary windings 31 of the series transformers 3v and 3w.

The switch 5 further comprises a control section 53, a switching circuit 54, output transformers 55a, 55b, differentiation circuits 56a, 56b and detection circuits 57a, 57b. Each of the output transformers 55a and 55b is configured similarly to the output transformer 55 of the first embodiment. A primary winding 55f of the output transformer 55a is connected between two taps connected to the primary winding 41 of the regulating transformer 4a. The primary winding 55f of the output transformer 55b is connected between two taps connected to the primary winding 41 of the regulating transformer 4b. Output transformer 55a, differentiation circuit 56a and detection circuit 57a are connected in the same manner as output transformer 55, differentiation circuit 56 and detection circuit 57 are. Output transformer 55b, differentiation circuit 56b and detection circuit 57b are connected in the same manner as output transformer 55, differentiation circuit 56 and detection circuit 57 are.

Output transformer 55a, differentiation circuit 56a and detection circuit 57a operate similarly to output transformer 55, differentiation circuit 56 and detection circuit 57, respectively. Output transformer 55b, differentiation circuit 56b and detection circuit 57b operate similarly to output transformer 55, differentiation circuit 56 and detection circuit 57, respectively. Two terminals of the secondary windings 62 of the three measuring transformers 6a, 6b, and 6c are connected to the control section 53 .

As in the first embodiment, the control unit 53 instructs the switching circuit 54 to switch between the three first switch circuits A1, A2, A3 and the three second switch circuits B1, B2, B3 included in the aggregate 50a. and the state of the series switch circuit 51a. As a result, among the three taps T1, T2, and T3 connected to the secondary winding 42 of the regulating transformer 4a, specific terminals of the primary windings 31 of the two series transformers 3u and 3v are connected. The tap to be played is switched. In the switching process for performing this switching, the control unit 53 determines whether or not to switch the connection destination of one or both of the two specific terminals based on, for example, the effective value of the AC voltage between the distribution lines U and V on the output side. judge. Furthermore, the control unit 53 determines whether or not the gradient of the AC voltage output from the secondary winding 42 of the adjustment transformer 4a is 0 degree.

As in the first embodiment, the control unit 53 instructs the switching circuit 54 to switch the three first switch circuits A1, A2, A3 and the three second switch circuits B1, B2, B3 included in the aggregate 50b. and the state of the series switch circuit 51b. As a result, among the three taps T1, T2, and T3 connected to the secondary winding 42 of the regulating transformer 4b, specific terminals of the primary windings 31 of the two series transformers 3v and 3w are connected. The tap to be played is switched. In the switching process for performing this switching, the control unit 53 determines whether or not to switch the connection destination of one or both of the two specific terminals based on, for example, the effective value of the AC voltage between the distribution lines U and W on the output side. judge. Furthermore, the control unit 53 determines whether or not the gradient of the AC voltage output from the secondary winding 42 of the adjustment transformer 4b is 0 degrees.

When the switching circuit 54 performs the two switching operations described above, the AC voltages applied across each of the three primary windings 31 change, and the three AC voltages on the output distribution lines U, V, W change. The rms value is adjusted. In voltage regulator 1 according to the second embodiment, switch 5 can switch connection destinations of three specific terminals in a short period of time, as in the first embodiment. At least one connection destination among the three specific terminals is switched without disconnection between two of the three specific terminals. It is unlikely that an excessive current will flow through one primary winding 31 in series transformers 3u, 3v, 3w.

(Embodiment 3)
In Embodiment 2, the number of regulating transformers is two. However, the number of regulating transformers may be three.
In the following, the points of the third embodiment that differ from the second embodiment will be described. Other configurations except those described later are the same as in the second embodiment, so the same reference numerals as in the second embodiment are given to the components common to the second embodiment, and the description thereof is omitted. do.

FIG. 10 is a block diagram showing the main configuration of the voltage regulator 1 according to the third embodiment. Compared to the second embodiment, the voltage regulator 1 further comprises a regulating transformer 4c configured similarly to the regulating transformer 4a. A primary winding 41 of the regulating transformer 4c is connected between the distribution lines U and W. The connection of the three primary windings 41 is delta connection. An AC voltage between distribution lines U and W on the output side is applied to both ends of the primary winding 41 of the regulating transformer 4c. Three taps T1, T2 and T3 are connected to the secondary winding 42 of the regulating transformer 4c. The secondary windings of each of the three regulating transformers 4a, 4b, 4c act as tap windings.

FIG. 11 is a block diagram showing the essential configuration of the switch 5. As shown in FIG. Compared to the second embodiment, the switch 5 further comprises an assembly 50c constructed similarly to the assembly 50 of the first embodiment. One terminal of the three primary windings 31 functions as a specific terminal. The other terminal of the primary winding 31 of the series transformer 3u is connected to a specific terminal of the primary winding 31 of the series transformer 3w. The other terminal of the primary winding 31 of the series transformer 3v is connected to a specific terminal of the primary winding 31 of the series transformer 3u. The other terminal of the primary winding 31 of the series transformer 3w is connected to a specific terminal of the primary winding 31 of the series transformer 3v. The connection of the three primary windings 31 is a Y connection. The assembly 50c is connected to three taps T1, T2, T3 connected to the secondary winding 42 of the regulating transformer 4c, like the assembly 50a of the second embodiment.

A specific terminal of the primary winding 31 of the series transformer 3w is connected to the first switch circuits A1, A2, A3 of the assembly 50a. A specific terminal of the primary winding 31 of the series transformer 3v is connected to the first switch circuits A1, A2, A3 of the assembly 50b. A specific terminal of the primary winding 31 of the series transformer 3u is connected to the first switch circuits A1, A2, A3 of the assembly 50c. A series circuit including a series switch circuit 51a and a resistor 52a is connected between specific terminals of the primary windings 31 of the series transformers 3v and 3w. A series circuit including a series switch circuit 51b and a resistor 52b is connected between specific terminals of the primary windings 31 of the series transformers 3u and 3v. Three second switch circuits B1, B2, and B3 are connected to the connection terminals of the aggregates 50a, 50b, and 50c, respectively. The connection terminal of the assembly 50a is connected to the connection terminals of the assemblies 50b and 50c.

In Embodiment 3, for example, the control unit 53 executes switching processing as follows. The control unit 53 controls at least one of the three specific terminals based on the effective value of the AC voltage between the distribution lines U and V on the output side and the effective value of the AC voltage between the distribution lines U and W on the output side. It is repeatedly determined whether or not to switch the connection destination. When determining to switch the connection destination, the control unit 53 instructs the switching circuit 54 to switch the states of the two series switch circuits 51a and 51b to the cutoff state. Next, the control unit 53 instructs the switching circuit 54 to switch between the nine first switch circuits A1, A2, A3 and the nine second switch circuits B1, B2, B3 of the aggregates 50a, 50b, 50c. , the state of the switch circuit, which is in the conductive state, is switched to the cut-off state.

Next, the control unit 53 instructs the switching circuit 54 to switch between the nine first switch circuits A1, A2, A3 and the nine second switch circuits B1, B2, B3 of the aggregates 50a, 50b, 50c. The state of the six switch circuits is switched to the conductive state. As a result, the connection destination of at least one specific terminal is switched. Finally, the control unit 53 instructs the switching circuit 54 to switch the states of the two series switch circuits 51a and 51b to the cutoff state, and ends the switching process. After that, the control unit 53 executes the switching process again.

When the control unit 53 executes the switching process, the AC voltage applied across each of the three primary windings 31 changes, and the effective values of the three AC voltages on the output-side distribution lines U, V, W change to adjusted. In the voltage regulator 1 according to the third embodiment, as in the second embodiment, the switch 5 can switch connection destinations of the three specific terminals in a short period of time. At least one connection destination among the three specific terminals is switched without disconnection between two of the three specific terminals.

In the third embodiment, the controller 53 changes the state of the series switch circuit 51a from the disconnected state to the conductive state when the gradient of the AC voltage between the two taps Ti of the adjustment transformers 4a and 4b is 0 degree. may be switched to The integer i may be any of 1, 2 and 3, as described in the description of the first embodiment. Similarly, when the slope of the AC voltage between the two taps T1 of the adjustment transformers 4b and 4c is 0 degree, the control unit 53 switches the state of the series switch circuit 51a from the blocking state to the conducting state. good.

In Embodiments 1 to 3, the number of taps provided in the tap winding is not limited to 3, and may be 2 or 4 or more. For each cluster 50, 50a, 50b, 50c, the number of first switch circuits is the same as the number of taps connected to one tap winding. The number of second switch circuits is also the same as the number of taps connected to one tap winding.

The technical features (components) described in Embodiments 1 to 3 can be combined with each other, and new technical features can be formed by combining them.
The disclosed embodiments 1 to 3 should be considered as examples in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above-described meaning, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

1 voltage regulator, 3u, 3v, 3w series transformer, 31 primary winding, 32 secondary winding, 40 single winding (tap winding), 42 secondary winding (tap winding), 5 switch , 51, 51a, 51b series switch circuits 52, 52a, 52b resistors 53 control unit (determining unit) 54 switching circuits A1, A2, A3 first switching circuits B1, B2, B3 second switching circuits D1 First diode, D2 Second diode, G1 First semiconductor switch, G2 Second semiconductor switch, T1, T2, T3 Tap, U, V, W Distribution line

Claims (5)

A voltage regulator that regulates the effective value of an alternating voltage,
one or more tap windings to which multiple taps are connected;
a plurality of transformers having primary and secondary windings;
Among the plurality of taps connected to the one or the plurality of tap windings, the taps electrically connected to each of the plurality of specific terminals among the terminals of the plurality of primary windings of the plurality of transformers. and a switch for switching
The effective value of the alternating voltage between two of the plurality of taps connected to the tap winding is adjusted according to the effective value of the alternating voltage between two of the plurality of distribution lines,
each of the plurality of secondary windings of the plurality of transformers is arranged in the middle of the plurality of distribution lines;
The switch has a plurality of switch circuits that switch between a conductive state in which current flow is possible and a cutoff state in which current flow is cut off,
Each switch circuit is
a first semiconductor switch;
a second semiconductor switch connected in series with the first semiconductor switch;
a first diode connected across the first semiconductor switch;
a second diode connected across the second semiconductor switch;
A voltage regulator, wherein the cathodes or anodes of the first diode and the second diode are interconnected. the switch has a resistance,
The plurality of switch circuits are
a plurality of tap switch circuits connected to each of the plurality of taps connected to the one or more tap windings;
a series switch circuit connected in series with the resistor;
At least two of the plurality of tap switch circuits are connected to each of the plurality of specific terminals,
2. The voltage regulator according to claim 1, wherein a series circuit including said resistor and a series switch circuit is connected between two of said plurality of specific terminals. The switch is
a determination unit that determines whether the slope of the AC voltage between two taps connected to one tap winding is 0 degrees;
a switching circuit that switches the states of the plurality of switch circuits to the conducting state or the blocking state,
The switching circuit is
The voltage regulator according to claim 2, wherein the state of the series switch circuit is switched from the cut-off state to the conducting state when the determination unit determines that the inclination is 0 degrees. the first semiconductor switch and the second semiconductor switch are IGBTs;
the emitters or collectors of the first semiconductor switch and the second semiconductor switch are connected to each other;
The voltage regulator according to any one of claims 1 to 3, wherein cathodes of the first diode and the second diode are connected to collectors of the first semiconductor switch and the second semiconductor switch. the first semiconductor switch and the second semiconductor switch are MOSFETs;
the sources or drains of the first semiconductor switch and the second semiconductor switch are connected to each other;
the first diode is a parasitic diode of the first semiconductor switch;
The voltage regulator according to any one of claims 1 to 3, wherein the second diode is a parasitic diode of the second semiconductor switch.

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