JP2023114741A - Voltage adjusting device - Google Patents

Abstract

To provide a voltage adjusting device that does not need to connect a series circuit including a serial switch and a resistor to a terminal of primary winding.SOLUTION: A voltage adjusting device 1 adjusts an effective value of an AC voltage. A switcher 5 switches a tap to be electrically connected to a specific terminal of primary winding 31 among three taps T1, T2, and T3 which are connected to single winding 40. An effective value of an AC voltage between the taps T1 and T2 is adjusted according to an effective value of an AC voltage between two distribution lines U and V. Two pieces of secondary winding 32 included in two series transformers 3u and 3v are arranged in the middle of the two distribution lines U and V. In the switcher 5, a control unit 53 limits a flow direction of a circuit current flowing through an upper side switch circuit in a flow state into a first direction or a second direction according to a current value of the circuit current flowing through the upper side switch circuit in the flow state.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to voltage regulators.

Patent Literature 1 discloses a voltage regulator that regulates the effective value of AC voltage between two distribution lines. In this voltage regulator, a tap winding to which a plurality of taps are connected is arranged. One terminal of a plurality of first switches is connected to each of the plurality of taps of the tap winding. Each of the plurality of taps of the tap winding is further connected to one terminal of a plurality of second switches. The other terminals of the plurality of first switches are connected to one terminals of the two primary windings of the two transformers. The other terminals of the plurality of second switches are connected to the other terminals of the two primary windings of the two transformers.

Each of the two secondary windings of the two transformers is arranged in the middle of the two distribution lines. Regarding the tap windings, the effective values of the AC voltages output from the two taps are adjusted according to the effective values of the AC voltages between the two distribution lines. When one of the plurality of first switches and one of the plurality of second switches are switched on, an alternating voltage is applied from the tap winding to the two primary windings to provide a voltage between the two distribution lines. The rms value of the AC voltage rises or falls. When the ON switch among the plurality of first switches or the plurality of second switches is changed, the AC voltage applied to the two primary windings is changed. This changes the AC voltage output to the outside.

In the voltage regulator disclosed in Patent Document 1, a series circuit of a shorting switch and a resistor is connected across the primary winding. When changing the ON switch among the plurality of first switches or the plurality of second switches, the bridging switch is turned on. Next, the ON switches are changed among the plurality of first switches or the plurality of second switches. Finally, the bracing switch is switched off. Therefore, current flow through the primary winding is not interrupted.

JP 2021-175274 A

In the voltage regulator described in Patent Literature 1, when the bracing switch is on, power flows through the resistor and power is consumed. If it is possible to realize a configuration that does not require connecting a series circuit including a cursive switch and a resistor to the terminals of the primary winding, it is possible to realize a voltage regulator with low power consumption.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a voltage regulator that eliminates the need to connect a series circuit including a short-circuit switch and a resistor to the terminals of the primary winding. to do.

A voltage regulating device according to one aspect of the present invention is a voltage regulating device that adjusts the effective value of an alternating voltage, and includes a tap winding to which a plurality of taps are connected, a primary winding, and a secondary winding. a plurality of transformers, and a switcher for switching, among the plurality of taps, a tap to which a specific terminal of the primary winding is electrically connected; The effective value is adjusted according to the effective value of the AC voltage between two distribution lines among the plurality of distribution lines, and each of the plurality of secondary windings of the plurality of transformers is in the middle of the plurality of distribution lines. , wherein the switch includes a plurality of switch circuits that switch between a conducting state in which current can flow and a cutoff state in which current flow is interrupted; and a control for the plurality of switch circuits. and a controller for conducting a circuit current flowing through the switch circuit in the conductive state according to a current value of the circuit current flowing through the switch circuit in the conductive state. Limit the direction to the first direction or the second direction.

According to the above aspect, it is not necessary to connect a series circuit including a cursing switch and a resistor to the terminals of the primary winding.

1 is a circuit diagram of a voltage regulator according to Embodiment 1; FIG. 4 is a circuit diagram of an upper switch circuit and a lower switch circuit; FIG. FIG. 2 is a block diagram showing the main configuration of a controller; FIG. 4 is a timing chart for explaining a change in the upper switch circuit or the lower switch circuit in the conductive state and limitation of the direction of circuit current flow; 4 is a flow chart showing a procedure of direction restriction processing; 4 is a flowchart showing a procedure of tap switching processing; FIG. 10 is a circuit diagram of a voltage regulator according to Embodiment 2; FIG. 10 is a circuit diagram of a voltage regulator according to Embodiment 3;

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 voltage regulator 1 according to the first embodiment. An AC power supply 2 is connected between two distribution lines U and V. The AC power supply 2 is, for example, a substation, and outputs an AC voltage to the voltage regulator 1 via two distribution lines U and V. As shown in FIG. The voltage regulator 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 alternating voltage between the distribution lines U and V on the output side based on the effective value of the alternating voltage between the distribution lines U and V on the input side.

The voltage regulator 1 has two series transformers 3u, 3v, a regulating transformer 4 and a switch 5. In each of the series transformers 3u and 3v, a primary winding 31 and a secondary winding 32 are wound around an annular core 30 made of a magnetic material. In the regulating transformer 4, 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 is connected in the middle of the single winding 40 . The number of turns of the single winding 40 between taps T1 and T2 is different from the number of turns of the single winding 40 between taps T2 and T3. A single winding 40 functions as a tap winding.

One terminal of each of the two secondary windings 32 is connected to distribution lines U and V on the input side. The other terminals of the two secondary windings 32 are connected to distribution lines U and V on the output side. The one terminal and the other terminal of one primary winding 31 are connected to the one terminal and the other terminal of the other primary winding 31, 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. One terminal of the neutral wire Q is connected to the middle of the single winding 40 . Regarding the single winding 40, the number of turns between the distribution line U and the neutral conductor Q matches the number of turns between the distribution line V and the neutral conductor Q.

The switch 5 has an assembly 50 , a current sensor 51 , a voltage sensor 52 and a controller 53 . The aggregate 50 has three upper switch circuits A1, A2, A3 and three lower switch circuits B1, B2, B3. In the following, any integer is represented by i. The integer i can be any of 1, 2 and 3. One terminal of each of the upper switch circuit Ai and the lower switch circuit Bi is connected to the tap Ti. The other terminal of each of the three upper switch circuits A1, A2, A3 is connected to a first connection node between one terminals of the primary winding 31 via a common current sensor 51. FIG. The other terminal of each of the three lower switch circuits B1, B2, B3 is connected to the second connection node between the other terminals of the primary winding 31. As shown in FIG. In FIG. 1, the first connection node and the second connection node are located on the right and left sides, respectively. Current sensor 51 is further connected to controller 53 . Voltage sensor 52 is connected to taps T1, T2 and controller 53 .

The controller 53 sets the state of each of the three upper switch circuits A1, A2, A3 and the lower switch circuits B1, B2, B3 to a conducting state in which current can flow or a state in which current does not flow. switch to the interrupted state. Normally, one of the three upper switch circuits A1, A2, A3 is in the conducting state and the rest of the upper switch circuits are in the blocking state. Similarly, typically one of the three lower switch circuits B1, B2, B3 is in the conducting state and the rest of the lower switch circuits are in the blocking state. One of the three taps T1, T2, T3 is electrically connected to each of the first node and the second node.

An AC voltage is applied across the output-side distribution lines U and V across the single winding 40 . A single winding 40 applies a common AC voltage to the two primary windings 31 from two of the three taps T1, T2, T3. When the upper switch circuit or the lower switch circuit in the conductive state is changed, the effective value or phase of the AC voltage applied by the single winding 40 to the two primary windings 31 is changed.

When AC voltage is applied to the two primary windings 31, the two secondary windings 32 raise or lower the effective value of the AC voltage between the distribution lines U and V on the input side. The AC voltage whose effective value has increased or decreased is output to the outside as an AC voltage between the distribution lines U and V on the output side. Since the method of increasing or decreasing the effective value is a well-known method, detailed description of this method will be omitted.

In FIG. 1, when the polarity of the voltage of the distribution line U is positive with respect to the potential of the distribution line V, the direction of the current flowing when the effective value of the AC voltage increases is indicated by the dashed arrow. . Current flows from the first node to the second node in the primary winding 31 . In a similar case, current flows in the primary winding 31 from the second node to the first node when the rms value of the alternating voltage drops. When the polarity of the voltage on the line U is negative, the direction of current is opposite to the direction of current when the polarity of the line U is positive. The greater the effective value of the AC voltage applied to the primary winding 31, the greater the range of increase or decrease. Changing the direction of the current flowing through the primary winding 31 corresponds to changing the phase of the AC voltage applied to the primary winding 31 .

The controller 53 controls which of the three taps T1, T2, T3 is electrically connected to the first node or the second node by changing the upper switch circuit or the lower switch circuit in the conductive state. switch. Each of the one terminal and the other terminal of the two primary windings 31 functions as a specific terminal.

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 between the two distribution lines U,V. The effective value of AC voltage between two taps is represented by the product of the effective value of AC voltage between two distribution lines U and V and the turns ratio. The turns ratio is the value obtained by dividing the number of turns in the single winding 40 between the two taps by the total number of turns in the single winding 40 .

The voltage sensor 52 detects the voltage value (instantaneous value) of the AC voltage between the taps T1 and T2 and outputs a voltage signal indicating the detected voltage value to the controller 53 . The effective value of the AC voltage between the taps T1 and T2 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 for the taps T1 and T2. The phase of the alternating voltage between the taps T1 and T2 matches the phase of the alternating voltage between the distribution lines U and V on the output side.

In the following description, a circuit current is defined as a current that flows through the switch circuits in the conductive state among the upper switch circuits A1, A2, A3 and the lower switch circuits B1, B2, B3. The current sensor 51 detects the current value (instantaneous value) of the circuit current flowing through the upper switch circuits in the conductive state among the three upper switch circuits A1, A2, and A3. The current sensor 51 outputs a current signal indicating the detected current value to the controller 53 . Hereinafter, the flow direction of the circuit current flowing from the aggregate 50 toward the first node is referred to as the left direction. The direction in which the circuit current flows from the first node toward the aggregate 50 is referred to as the right direction. When the direction of the circuit current flowing through the conductive upper switch circuit is leftward, the current value indicated by the current signal is a positive value. If the current direction of the circuit current flowing through the conductive upper switch circuit is rightward, the current value indicated by the current signal is a negative value.

FIG. 2 is a circuit diagram of the upper switch circuit A1 and the lower switch circuit B2. The configuration of each of the upper switch circuits A2 and A3 is the same as that of the upper switch circuit A1. The configurations of the lower switch circuits B1 and B3 are the same as the configuration of the lower switch circuit B1. FIG. 2 shows first and second examples of the upper switch circuit A1 and the lower switch circuit B2.

Each of the upper switch circuits A1, A2, A3 and the lower switch circuits B1, B2, B3 has a first switch G1, a second switch G2, a first diode D1 and a second diode D2. Each of the first switch G1 and the second switch G2 is an IGBT (Insulated Gate Bipolar Transistor). The first switch G1 is connected in series with the second switch G2. A cathode and an anode of a first diode D1 are connected to the collector and emitter of the first switch G1, respectively. Similarly, the cathode and anode of a second diode D2 are connected to the collector and emitter of the second switch G2, respectively. Gates of the first switch G1 and the second switch G2 are separately connected to the controller 53 .

In a first example, the anodes of the first diode D1 and the second diode D2 are connected together. A collector of the first switch G1 of each of the upper switch circuits A1, A2, A3 is connected to the first node. The collectors of the second switches G2 of the upper switch circuits A1, A2, A3 are connected to the taps T1, T2, T3. A collector of the first switch G1 of each of the lower switch circuits B1, B2, B3 is connected to the second node. The collectors of the second switches G2 of the lower switch circuits B1, B2, B3 are connected to the taps T1, T2, T3.

In a second example, the cathodes of the first diode D1 and the second diode D2 are connected together. The emitter of the second switch G2 of each of the upper switch circuits A1, A2, A3 is connected to the first node. The emitters of the first switches G1 of the upper switch circuits A1, A2, A3 are connected to the taps T1, T2, T3. The emitter of the second switch G2 of each of the lower switch circuits B1, B2, B3 is connected to the second node. The emitters of the first switches G1 of the lower switch circuits B1, B2, B3 are connected to the taps T1, T2, T3.

The controller 53 turns the first switch G1 on or off by adjusting the voltage at the gate of the first switch G1. Similarly, the controller 53 turns the second switch G2 on or off by adjusting the voltage at the gate of the second switch G2. For each of the first switch G1 and the second switch G2, when the state is on, current can flow through the collector and the emitter in that order. For each of the first switch G1 and the second switch G2, when the state is off, current flow through the collector and emitter is blocked.

When the controller 53 switches off the first switch G1 and the second switch G2 in the conducting state of the upper switch circuit or the lower switch circuit, the state transitions to the interrupted state. When the controller 53 turns on at least one of the first switch G1 and the second switch G2 in the upper switch circuit or the lower switch circuit in the interrupted state, the state transitions from the interrupted state to the conducting state.

The controller 53 limits the flow direction of the circuit current to the left by switching off and on the first switch G1 and the second switch G2 respectively in the upper switch circuit or the lower switch circuit in the conductive state. . When the flow direction is restricted to the left, the circuit current flows through the second switch G2 and the first diode D1 in that order. The controller 53 limits the flow direction to the right by switching on and off the first switch G1 and the second switch G2 respectively in the upper switch circuit or the lower switch circuit in the conducting state. When the flow direction is restricted to the right, the circuit current flows through the first switch G1 and the second diode D2 in that order. The controller 53 turns on both the first switch G1 and the second switch G2 in the conducting state of the upper switching circuit or the lower switching circuit, thereby removing the restrictions on the conduction direction. The left direction and right direction correspond to the first direction and the second direction, respectively.

As shown in FIG. 2, when the controller 53 restricts the flow direction of the circuit current flowing through the conductive upper switch circuit to the left, the circuit flowing through the conductive lower switch circuit Limit the direction of current flow to the right. As a result, a current flows as indicated by solid arrows. Similarly, when the controller 53 restricts the flow direction of the circuit current flowing through the conductive upper switch circuit to the right, the controller 53 controls the flow of the circuit current through the conductive lower switch circuit. Limit direction to left. This causes current to flow as indicated by the dashed arrows.

Therefore, the current value of the leftward circuit current flowing through the conductive upper switch circuit matches the current value of the rightward circuit current flowing through the conductive lower switch circuit. Similarly, the current value of the rightward circuit current flowing through the conducting upper switch circuit matches the current value of the leftward circuit current flowing through the conducting lower switch circuit.

The first switch G1 and the second switch G2 may be FETs (Field Effect Transistors). In this case, the drain and source correspond to the collector and emitter, respectively. When the FET is on, current can flow in both directions through the drain and source. When the first switch G1 and the second switch G2 are FETs, the parasitic diodes of the first switch G1 and the second switch G2 may be used as the first diode D1 and the second diode D2, respectively. When the first switch G1 and the second switch G2 are on, no current flows through the first diode D1 or the second diode D2.

FIG. 3 is a block diagram showing the essential configuration of the controller 53. As shown in FIG. The controller 53 has a differentiation circuit 60 , a zero slope detection circuit 61 , a zero current detection circuit 62 and a control circuit 63 . Voltage sensor 52 outputs a voltage signal to differentiation circuit 60 . The differentiating circuit 60 outputs to the slope zero detecting circuit 61 an alternating voltage indicated by the voltage signal, that is, a differentiating signal indicating a differentiated value of the alternating voltage between the taps T1 and T2. The slope zero detection circuit 61 outputs a slope zero signal to the control circuit 63, which indicates the slope zero point in time when the differential value indicated by the differential signal becomes zero. When the differential value is 0, the gradient of the AC voltage between the distribution lines U and V is 0 degrees.

The current sensor 51 outputs a current signal to the zero current detection circuit 62 and the control circuit 63 . The current zero detection circuit 62 outputs to the control circuit 63 a current zero signal indicating a current zero point in time when the current value of the circuit current indicated by the current signal becomes 0A. A switching signal is input to the control circuit 63 to instruct switching of the tap to which one terminal or the other terminal of the primary winding 31 is connected.

The control circuit 63 switches on or off each of the six first switches G1 and the six second switches G2 by separately controlling the voltages of the gates of the six first switches G1 and the six second switches G2. . Based on the zero slope signal, zero current signal, current signal, or switching signal, the control circuit 63 changes the conducting state of the upper switching circuit or the lower switching circuit and limits the direction of conduction of the circuit current.

The control circuit 63 is preferably configured using a logic circuit, FPGA (Field Programmable Gate Array), or the like. The control circuit 63 has processing elements. The processing elements of control circuit 63 perform various processes by executing computer programs.

FIG. 4 is a timing chart for explaining the change of the upper switch circuit or the lower switch circuit in the conduction state and the limitation of the direction of circuit current conduction. In FIG. 4, the transition of the voltage value indicated by the voltage signal is indicated by the dashed-dotted line. A change in the current value of the circuit current indicated by the current signal is indicated by a thin solid line. Transition of the differential value indicated by the differential signal is indicated by a thick solid line. The voltage value indicated by the voltage signal is the voltage value of the tap T1 with reference to the potential of the tap T2.

The transition of the voltage value indicated by the voltage signal is the waveform of the AC voltage between the taps T1 and T2. The phase of the AC voltage between two taps among the three taps T1, T2 and T3 matches the phase of the AC voltage between the distribution lines U and V on the output side. When the slope of the AC voltage between the taps T1 and T2 is 0 degrees, the differential value indicated by the differential signal is 0. FIG. 4 shows the transition of the voltage value indicated by the zero-slope signal. A zero slope signal indicates a high level voltage value or a low level voltage value. In FIG. 4, the high level voltage value and the low level voltage value are indicated by "H" and "L" respectively. Each time the differential value indicated by the differential signal becomes 0, the voltage value indicated by the zero-slope signal switches to a high-level voltage value or a low-level voltage value.

A current zero signal also indicates a high level voltage value or a low level voltage value. Each time the current value of the circuit current indicated by the current signal becomes 0 A, the voltage value indicated by the current zero signal switches to a high level voltage value or a low level voltage value.

FIG. 4 shows transitions in the states of the first and second switches G1 and G2 of the upper switch circuits A1 and A2, and transitions in the states of the first and second switches G1 and G2 in the lower switch circuits B2 and B3. is shown. In the description of FIG. 4, the states of the upper switch circuit A3 and the lower switch circuit B1 are maintained in the disconnected state.

On the left side of FIG. 4, at least one of the first switch G1 and the second switch G2 is on for the upper switch circuit A1 and the lower switch circuit B2. Therefore, the states of the upper switch circuit A1 and the lower switch circuit B2 are conductive. One terminal and the other terminal of the primary winding 31 are electrically connected to taps T1 and T2, respectively. Both the first switch G1 and the second switch G2 are off for the upper switch circuit A2 and the lower switch circuit B3. Therefore, the state of the upper switch circuit A2 and the lower switch circuit B3 is the cutoff state.

The first switch G1 of the upper switch circuit A1 in the conducting state is off. Therefore, in the upper switch circuit A1, the flow direction of the circuit current is restricted to the left direction. The second switch G2 of the conductive lower switch circuit B2 is off. Therefore, in the lower switch circuit B2, the flow direction of the circuit current is restricted to the right direction. The current value indicated by the current signal is positive.

The control circuit 63 switches the first switch G1 of the upper switch circuit A1 from off to on when the current value of the circuit current flowing through the conducting upper switch circuit A1 drops to a value below the positive upper threshold. . Further, the control circuit 63 switches the second switch G2 of the lower switch circuit B2 from off to on. As a result, the first switch G1 and the second switch G2 are turned on in the upper switch circuit A1 and the lower switch circuit B2, respectively, which are in the conductive state, and there is no restriction on the direction of flow of the circuit current. A circuit current can flow in both directions through the upper switch circuit A1 and the lower switch circuit B2 in the conducting state.

When the current value of the circuit current flowing through the upper switch circuit A1 in the conductive state decreases to a value equal to or lower than the negative lower threshold in the case where there is no restriction on the flow direction of the circuit current, the control circuit 63 The second switch G2 of the switch circuit A1 is switched from on to off. Further, the control circuit 63 switches the first switch G1 of the lower switch circuit B2 from on to off. As a result, the direction of flow of the circuit current through the upper switch circuit A1 and the lower switch circuit B2 is restricted to the right direction and the left direction.

When the direction of the circuit current flowing through each of the upper switch circuit A1 and the lower switch circuit B2 is restricted to the right direction and the left direction, the circuit current that flows through the upper switch circuit A1 in the conductive state rises above the negative lower threshold, the control circuit 63 switches the second switch G2 of the upper switch circuit A1 from off to on. Further, the control circuit 63 switches the first switch G1 of the lower switch circuit B2 from off to on. This eliminates restrictions on the direction of flow of circuit current.

In the case where there is no restriction on the flow direction of the circuit current, if the current value of the circuit current flowing through the conducting state of the upper switch circuit A1 rises to a value equal to or higher than the positive upper threshold, the control circuit 63 Switch the first switch G1 of the circuit A1 from on to off. Further, the control circuit 63 switches the second switch G2 of the lower switch circuit B2 from on to off. As a result, the direction of flow of the circuit current that flows through each of the upper switch circuit A1 and the lower switch circuit B2 is restricted to the left direction and the right direction.

As described above, according to the current value of the circuit current flowing through the conducting state of the upper switching circuit A1 and the lower switching circuit B2, the control circuit 63 controls the Limit the flow direction of the circuit current to the left or right. When the absolute value of the current value of the circuit current flowing through the upper switch circuit A1 and the lower switch circuit B2 in the conductive state is small, the control circuit 63 eliminates the restrictions on the direction of the circuit current. Therefore, the flow direction of the circuit current is smoothly changed.

Regarding the circuit current flowing through the upper switch circuit Ai, the upper threshold corresponds to the first threshold, and the absolute value of the lower threshold corresponds to the second threshold. Regarding the circuit current flowing through the lower switch circuit Bi, the absolute value of the lower threshold corresponds to the first threshold, and the upper threshold corresponds to the second threshold.

When a switching signal for switching the connection destination of one terminal and the other terminal of the primary winding 31 to the taps T2 and T3 is input to the control circuit 63, it waits until the differential value of the differential signal becomes zero. When the differentiated value of the differentiated signal becomes 0, the control circuit 63 switches the first switch G1 or the second switch G2 from off to on in each of the upper switch circuit A2 and the lower switch circuit B3. As a result, the state of each of the upper switch circuit A2 and the lower switch circuit B3 transitions from the cut-off state to the conducting state.

In the example of FIG. 4, the second switch G2 of the upper switch circuit A1 and the first switch G1 of the lower switch circuit B2 are on at the time point when the slope is zero. Therefore, the control circuit 63 switches on the second switch G2 of the upper switching circuit A2 and the first switch G1 of the lower switching circuit B3. As a result, the flow direction of the circuit current flowing through the upper switch circuits A1 and A2 is restricted to the left. The flow direction of the circuit current flowing through the lower switch circuits B2 and B3 is restricted to the right.

At this time, since the upper switch circuits A1 and A2 and the lower switch circuits B2 and B3 are in the conductive state, current flow through the primary winding 31 is not interrupted. Furthermore, the direction of the circuit current flowing through the upper switch circuits A1 and A2 is restricted to the same direction. The direction of the circuit current flowing through the lower switch circuits B2 and B3 is also restricted to the same direction. Therefore, no short circuit occurs between two taps among the three taps T1, T2 and T3. Therefore, it is not necessary to connect a series circuit in which a straight-through switch and a resistor are connected in series between both terminals of the primary winding 31 . Power consumption is low because current does not flow through the short-circuit resistor.

Note that when the first switch G1 of the upper switch circuit A1 and the second switch G2 of the lower switch circuit B2 are on at the time when the slope is zero, the control circuit 63 controls the first switch G1 of the upper switch circuit A2. G1 and the second switch G2 of the lower switch circuit B3 are switched on.

After the upper switch circuits A1, A2 and the lower switch circuits B2, B3 transition to the conducting state, the control circuit 63 switches the first switch G1 and the second switch G2 on the upper switch circuit A1 and the lower switch circuit B2, respectively. switch off the switch that is on in the . As a result, among the upper switch circuits A1, A2, and A3, the upper switch circuit in the conductive state is changed to the upper switch circuit A2. Among the lower switch circuits B1, B2, and B3, the lower switch circuit in the conduction state is changed to the lower switch circuit B3.

After that, the control circuit 63 controls the current value of the circuit current flowing through the conducting state of the upper switching circuit A2 and the lower switching circuit B3 according to the current value of the circuit current flowing through the conducting state of the upper switching circuit A2 and the lower switching circuit B3. Limit the flow direction to the left or right. The method of limiting the direction of the circuit current flowing through the upper switch circuits A2 and A3 in the conductive state is the same as the method of limiting the direction of the circuit current flowing through the upper switch circuit A1 in the conductive state. be. The method of limiting the direction of the circuit current flowing through the lower switch circuits B1 and B3 in the conductive state is the same as the method of limiting the direction of the circuit current flowing through the lower switch circuit B2 in the conductive state. It is the same.

The control circuit 63 of the controller 53 performs direction limiting processing and tap switching processing by executing a computer program. The direction restriction processing is processing for restricting the flow direction of the circuit current flowing through each of the upper switch circuit and the lower switch circuit in the conductive state. The upper switch circuit in the conductive state is appropriately changed among the three upper switch circuits A1, A2 and A3. Similarly, the conductive lower switch circuit is appropriately changed among the three lower switch circuits B1, B2 and B3. The tap switching process is a process of switching the tap to which at least one of the one terminal and the other terminal of the primary winding 31 is electrically connected.

FIG. 5 is a flow chart showing the procedure of direction restriction processing. In the direction limiting process, the control circuit 63 first determines whether or not the current value of the circuit current indicated by the current signal is less than the upper threshold (step S1). Next, when the control circuit 63 determines that the current value of the circuit current is less than the upper threshold (S1: YES), it determines whether the current value of the circuit current indicated by the current signal is greater than or equal to the lower threshold. (step S2). As mentioned above, the lower threshold is a negative value.

When the control circuit 63 determines that the current value of the circuit current is equal to or greater than the upper threshold (S1: NO), or determines that the current value of the circuit current is less than the lower threshold (S2: NO), It is determined whether or not the flow direction of the circuit current flowing through the upper switch circuit and the lower switch circuit in the conducting state is restricted (step S3). If the control circuit 63 determines that the current flow direction is not restricted (S3: NO), the control circuit 63 limits the current flow direction of the circuit current flowing through the upper switch circuit and the lower switch circuit in the current state (step S4).

In step S4, the control circuit 63 switches off one of the first switch G1 and the second switch G2 for each of the conductive upper switch circuit and the lower switch circuit. When the first switch G1 is switched off, the flow direction is restricted to the left. When the second switch G2 is switched off, the flow direction is restricted to the right. When the circuit current indicated by the current signal rises to a value equal to or higher than the upper threshold, in step S4, the flow direction of the circuit current flowing through the upper switch circuit and the lower switch circuit in the conducting state is changed leftward and rightward. limit to If the circuit current indicated by the current signal has decreased to a value less than the lower threshold value, in step S4, the circuit current flowing through the upper switch circuit and the lower switch circuit in the conductive state is changed to the right direction and the left direction. Directional restrictions.

When the control circuit 63 determines that the current value of the circuit current is equal to or higher than the lower threshold (S2: YES), the direction of the circuit current flowing through the upper switch circuit and the lower switch circuit in the conducting state is changed to It is determined whether or not there is a restriction (step S5). If the control circuit 63 determines that the current flow direction is restricted (S5: YES), the control circuit 63 removes the restriction on the current flow direction of the circuit current flowing through each of the upper switch circuit and the lower switch circuit in the current state. (Step S6). Specifically, in step S6, for each of the upper switch circuit and the lower switch circuit in the conducting state, the switches that are off among the first switch G1 and the second switch G2 are turned on.

If the control circuit 63 determines that the flow direction is restricted (S3: YES), it executes one of steps S4 and S6, or if it determines that the flow direction is not restricted (S5: YES). : NO), and terminates the direction restriction process. After completing the direction limiting process, the control circuit 63 executes the direction limiting process again. When the control circuit 63 executes the direction limiting process, as shown in FIG. 4, the conducting direction of the circuit current flowing through the conducting upper switching circuit and the lower switching circuit is limited.

FIG. 6 is a flowchart showing the procedure of tap switching processing. In the tap switching process, the control circuit 63 determines whether or not a switching signal has been input (step S11). When the control circuit 63 determines that the switching signal has not been input (S11: NO), it executes step S11 again. The control circuit 63 waits until the switching signal is input.

When the control circuit 63 determines that the switching signal is input (S11: YES), it determines whether the differential value indicated by the differential signal is 0 (step S12). When the control circuit 63 determines that the differential value is not 0 (S12: NO), it executes step S12 again. The control circuit 63 waits until the differential value of the differential signal becomes zero.

When the control circuit 63 determines that the differential value is 0 (S12: YES), whether or not the direction of the circuit current flowing through the upper switch circuit and the lower switch circuit in the conducting state is restricted. is determined (step S13). When the control circuit 63 determines that the flow direction of the circuit current is restricted (S13: YES), it determines whether the difference between the two zero points is less than a certain difference threshold (step S14). .

One zero point is the zero slope point. The other zero point is the current zero point. With respect to step S14, the difference between the two zero points is, for example, the previous zero point of slope detected before the current zero point of slope detected in step S12 and the first detected zero point of slope after the previous zero point of slope. is the difference from the time when the current is zero. In step S14, the control circuit 63 determines whether or not restrictions on the flow direction will be removed in the near future.

Note that the control circuit 63 may regard the difference between the latest two peak points as the difference between two zero time points with respect to the sinusoidal waveforms indicated by the differential signal and the current signal.

If the control circuit 63 determines that the flow direction is not restricted (S13: NO), or if it determines that the difference between the two zero points is less than the difference threshold (S14: YES), the flow state is It is determined whether or not the direction of the circuit current flowing through each of the upper switch circuit and the lower switch circuit is restricted (step S15). When the control circuit 63 determines that the flow direction is not restricted (S15: NO), it executes step S15 again. The control circuit 63 waits until the flow direction is restricted in the direction restriction process.

When the control circuit 63 determines that the difference between the two zero points is equal to or greater than the difference threshold (S14: NO), or determines that the flow direction is restricted (S15: YES), the flow state is change at least one of the upper switch circuit and the lower switch circuit (step S16). As described in the description of FIG. 4, the control circuit 63 changes the state of the upper switch circuit from the cut-off state to the conductive state, and then changes the state of the upper switch circuit from the conductive state to the cut-off state. As a result, the upper switch circuit in the conducting state is changed. The control circuit 63 changes the conductive lower switch circuit in the same manner as the conductive upper switch circuit.

After executing step S16, the control circuit 63 ends the tap switching process. After completing the tap switching process, the control circuit 63 executes the tap switching process again.

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 control circuit 63 changes at least one of the conducting state of the upper switching circuit and the lower switching circuit when the inclination of the output of the single winding 40 becomes 0 degree. Therefore, after at least one of the upper switch circuit and the lower switch circuit in the conductive state is changed, 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 , the magnetic flux of each of the two cores 30 is less likely to exceed the saturation magnetic flux, so the possibility of excessive current flowing through the primary winding 31 is low.

When the conducting state of the upper switching circuit or the lower switching circuit is changed in a state where the direction of the circuit current flowing through each of the conducting state of the upper switching circuit and the lower switching circuit is not restricted, 3. Two taps out of one tap T1, T2, T3 can be shorted. If the difference between the two zero points is small, the voltage regulator 1 waits without changing the conducting upper or lower switching circuit until the conduction direction is restricted. Therefore, it is unlikely that the upper switch circuit or the lower switch circuit in the conductive state will be changed in a state where the direction of flow of the circuit current is not restricted.

(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 the first embodiment, so the same reference numerals as in the first embodiment are given to the components that are common to the first embodiment, and the description thereof is omitted. do.

FIG. 7 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 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. 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). 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 and T2 of the regulating transformer 4a matches the phase of the AC voltage between the distribution lines U and V on the output side. The phase of the AC voltage between the taps T1 and T2 of the regulating transformer 4b matches the phase of the AC voltage between the distribution lines V and W on the output side.

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 upper 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 lower switch circuits B1, B2, B3 of the assembly 50a and the upper 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 lower 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 has two current sensors 51a, 51b and two voltage sensors 52a, 52b. The current sensors 51a and 51b respectively detect the current values of the circuit currents flowing through the upper switch circuits of the aggregates 50a and 50b in the conduction state. Voltage sensors 52a and 52b respectively detect voltage values (instantaneous values) of AC voltages between taps T1 and T2 of regulating transformers 4a and 4b, respectively.

The switch 5 has a controller 53 as in the first embodiment. The controller 53 individually changes the states of the six upper switch circuits A1, A2, A3 and the six lower switch circuits B1, B2, B3 of the aggregates 50a, 50b. As a result, the controller 53 causes each of the three specific terminals among the terminals of the three primary windings 31 among the six taps T1, T2, and T3 connected to the two secondary windings 42 to be electrically connected. switch the tap to be connected.

The controller 53 controls the states of the upper switch circuits A1, A2, A3 and the lower switch circuits B1, B2, B3 of the assembly 50a based on the values detected by the current sensor 51a and the voltage sensor 52a. , in the same manner as in form 1. The controller 53 controls the states of the upper switch circuits A1, A2, A3 and the lower switch circuits B1, B2, B3 of the assembly 50b based on the values detected by the current sensor 51b and the voltage sensor 52b. , in the same manner as in form 1. Aggregates 50 a and 50 b correspond to aggregate 50 . Current sensors 51 a and 51 b correspond to current sensor 51 . Voltage sensors 52 a and 52 b correspond to voltage sensor 52 . The voltage regulating device 1 according to the second embodiment has the same effects as the voltage regulating device 1 according to the first embodiment.

(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 those of the second embodiment, so the same reference numerals as those of the second embodiment are given to the components common to the second embodiment, and the description thereof is omitted. do.

FIG. 8 is a circuit diagram of 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. A secondary winding 42 of each of the three regulating transformers 4a, 4b, 4c functions as a tap winding.

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 delta 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 upper switch circuits A1, A2 and A3 of the assembly 50a. A specific terminal of the primary winding 31 of the series transformer 3v is connected to the upper 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 upper switch circuits A1, A2, A3 of the assembly 50c.

The switch 5 further has a current sensor 51c and a voltage sensor 52c. The current sensor 51c detects the current value of the circuit current flowing through the conductive upper switch circuit of the assembly 50c. The voltage sensor 52c detects the voltage value (instantaneous value) of the AC voltage between the taps T1 and T2 of the regulating transformer 4c.

The controller 53 of the switch 5 individually changes the states of the nine upper switch circuits A1, A2, A3 and the nine lower switch circuits B1, B2, B3 of the aggregates 50a, 50b, 50c. As a result, the controller 53 causes each of the three specific terminals among the terminals of the three primary windings 31 among the nine taps T1, T2, and T3 connected to the three secondary windings 42 to be electrically connected. switch the tap to be connected.

The controller 53 controls the states of the upper switch circuits A1, A2, A3 and the lower switch circuits B1, B2, B3 of the assembly 50c based on the values detected by the current sensor 51c and the voltage sensor 52c. , in the same manner as in form 1. Aggregate 50 c corresponds to aggregate 50 . A current sensor 51 c corresponds to the current sensor 51 . A voltage sensor 52 c corresponds to the voltage sensor 52 . The voltage regulating device 1 according to the third embodiment has the same effect as the voltage regulating device 1 according to the second embodiment.

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 upper switch circuits is the same as the number of taps connected to one tap winding. The number of lower switch circuits is also the same as the number of taps connected to one tap winding. The voltage value of the AC voltage detected by each of the voltage sensors 52, 52a, 52b, and 52c is not limited to the voltage value of the AC voltage between the taps T1 and T2. There is no problem if the AC voltage values detected by the voltage sensors 52, 52a, 52b, and 52c are the AC voltage values between two taps connected to one 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 meaning described above, 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, 5 switch, 31 primary winding, 32 secondary winding, 40 single winding (tap winding), 42 secondary winding (tap winding) , 53 controller, A1, A2, A3 upper switch circuit, B1, B2, B3 lower switch circuit,
D1 first diode, D2 second diode, G1 first switch, G2 second switch

Claims (5)

A voltage regulator that regulates the effective value of an alternating voltage,
a tap winding to which a plurality of taps are connected;
a plurality of transformers having primary and secondary windings;
a switch that switches, among the plurality of taps, a tap to which a specific terminal of the primary winding is electrically connected,
The effective value of the AC voltage between two of the plurality of taps is adjusted according to the effective value of the AC voltage between two distribution lines 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 is
a plurality of switch circuits that switch between a conductive state in which current can flow and a cutoff state in which current flow is cut off;
a controller for controlling the plurality of switch circuits,
The controller controls the flow direction of the circuit current flowing through the switch circuit in the conducting state to a first direction or a second direction according to the current value of the circuit current flowing through the switch circuit in the conducting state. limit to voltage regulators. Each switch circuit is
a first switch;
a second switch connected in series with the first switch;
a first diode connected across the first switch;
a second diode connected across the second switch;
the cathodes or anodes of the first diode and the second diode are connected to each other;
The controller is
limiting the flow direction to the first direction by switching off and on the first switch and the second switch, respectively, in the switch circuit in the conducting state;
2 . The voltage regulator according to claim 1 , wherein in the switching circuit in the conducting state, the conducting direction is restricted to the second direction by switching on and off the first switch and the second switch, respectively. The controller is
When the flow direction of the circuit current is restricted to the first direction, and the absolute value of the current value of the circuit current is reduced to a value less than a first threshold, the flow of the circuit current Eliminate direction restrictions,
When the flow direction of the circuit current is restricted to the second direction, and the absolute value of the current value of the circuit current decreases to a value less than a second threshold, the flow of the circuit current Eliminate direction restrictions,
When the current direction is not restricted and the absolute value of the current value of the circuit current whose current direction is the first direction rises to a value equal to or greater than the first threshold value, the circuit current restricting the flow direction to the first direction;
When the current direction is not restricted and the absolute value of the current value of the circuit current whose current direction is the second direction rises to a value equal to or greater than the second threshold value, the current value of the circuit current The voltage regulator according to claim 1 or 2, wherein the flow direction is restricted to the second direction. The controller changes the energized switch circuit among the plurality of switch circuits when the slope of the alternating voltage between the two taps connected to the tap winding becomes 0 degree. The voltage regulator according to any one of claims 1 to 3. The controller is
When the slope becomes 0 degrees, the difference between the time when the slope becomes 0 degrees and the time when the current value of the circuit current flowing through the conductive switch circuit becomes 0 A is less than the difference threshold. determine whether there is
If it is determined that the difference is less than the difference threshold, after limiting the conducting direction of the conducting switch circuit, the conducting switch circuit among the plurality of switch circuits is changed. The voltage regulator according to claim 4.

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