JP2002291230A - Three phase voltage regulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three phase voltage regulator which can maintain a positive and negative balance during conduction of each phase and suppress the magnetic noise and unwanted sounds by suppressing the DC excitation when an effective voltage from a three phase power supply is adjusted and controlled. SOLUTION: A pattern selecting means 9 selects a required pattern from a pattern storing means 8 for storing the patterns of switching timing of switching means 3-5 provided on three phase power lines. A timing generating means 10 inputs outputs from a zero-crossing detecting means 6 and a timer 7 in response to the required pattern When the switching means closes, the first closing signal for closing the switching means provided on two phases corresponding to arbitrary phases at a point of time when a voltage between the phases is zero, is outputted. When the electrical angle leads 90 degrees from the point of time of outputting the first closing signal, the second closing signal for closing the switching means on a remaining phase, is outputted. When the switching means opens, the first and second closing signals stop outputting at the point of time that arbitrary phase voltages are almost zero.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase voltage regulator for controlling the effective voltage applied to a load by cutting out a voltage waveform in a time series from a commercial power supply voltage.

[0002]

2. Description of the Related Art When an electric heater or an induction motor is applied as a load, the amount of heat and the number of revolutions can be controlled by changing the effective voltage. There are various methods of controlling the effective voltage, but since the main circuit is simple, a method that cuts out the voltage waveform in a time series from the commercial power supply voltage by a circuit configuration using a commutation arc-extinguishing element such as a thyristor or triac is widely used. It had been. In such a voltage adjusting device, a control method is roughly divided into a phase control method and a duty control method.

First, the phase control method will be described. FIG. 6 is a configuration diagram showing a conventional three-phase voltage regulator, and FIG. 7 is a timing chart showing the operation of the conventional three-phase voltage regulator. In FIG. 6, 1 is a three-phase power supply, 2 is a three-phase load (here, a resistor), 3 to 5 are triacs inserted in each phase, and 6 is a zero cross point indicating zero voltage of the R-S phase voltage. A zero-crossing detection circuit, 7 is time-measuring means for starting time measurement starting from the detection timing of the zero-crossing detection circuit 6, 8A is a pattern storage means, 9A is a pattern selection means, 10A is a detection timing of the zero-crossing detection circuit 6 and a time measurement of the timekeeping means 7 And timing generating means for calculating the opening / closing control timing of each of the triacs 3 to 5 based on the selection of the pattern selecting means 9A and outputting a drive signal for each of the triacs 3 to 5, and 11 according to the timing generated by the timing generating means 10A. This is driving means for outputting a driving signal to each of the triacs 3 to 5.

The operation of the conventional three-phase voltage regulator will be described with reference to FIG. The pattern selection means 9A is a phase angle of 0 to 180 degrees of a phase voltage electrical angle (half wave) stored in advance in the pattern storage means 8A in accordance with a ratio of a desired output effective voltage to a power supply voltage. Is selected.
(The phase voltage is delayed by 30 degrees with respect to the inter-phase voltage: ex. The R-phase voltage is delayed by 30 degrees with respect to the RS-phase voltage.) The timing generating means 10A includes the triacs 3 to 5 inserted in each phase.
Are turned on at a phase angle designated as a phase voltage electrical angle (half-wave), and turned off at 180 degrees. At this time, the timing generation means 10A determines the control timing based on the detection timing of the zero-cross detection circuit 6 and the time measurement by the time measurement means 7, and outputs a timing signal to the drive means. The drive means 11 receives the timing signal and outputs the R-phase, S-phase, and T-phase drive signals shown in FIG. By controlling in this way, the inter-phase voltage applied to the three-phase load can be controlled by the output VR-S and the output VS- shown in FIG.
T, output VT-R, and the output effective voltage can be output at an arbitrary ratio from zero voltage to the power supply voltage.

Next, the duty control method will be described. FIG. 8 is a configuration diagram showing a conventional single-phase voltage regulator using a duty control method, and FIG. 9 is a timing chart showing the operation of the conventional single-phase voltage regulator. In FIG.
21 is a single-phase power supply, 22 is a single-phase load (resistance here), 2
3 is a triac, 6 is a zero-cross detection circuit for detecting a zero-cross point indicating a zero voltage of the RS phase voltage, 7 is time-measuring means for starting time measurement from the detection timing of the zero-cross detection circuit 6, 24 is pattern storage means, 25 is a pattern selecting means, 26 is a timing generating means for calculating the opening / closing control timing of the triac 23 based on the detection timing of the zero-cross detecting circuit 6, the timing of the timing means 7 and the selection of the pattern selecting means 25, and 27 is a timing generating means 26. This is driving means for outputting a drive signal to the triac 23 in accordance with the output timing signal.

The operation of the conventional single-phase voltage regulator will be described with reference to FIG. The pattern selecting unit 25 sets the number of times of ON and OFF of the phase voltage (half wave) stored in advance in the pattern storing unit 24 in association with the ratio of the desired output effective voltage to the power supply voltage. The timing generation means 26 turns on the triac 23 at a phase angle of 0 degree as a phase voltage electrical angle (half wave), turns ON the predetermined half-wave count continuously, turns it OFF at the electrical angle of 180 °, and turns the triac 23 on at a predetermined half-wave count. Turn off. At that time, the timing generation means 2
Reference numeral 6 determines the control timing based on the detection timing of the zero-cross detection circuit 6 and the timing of the timing means 7, and outputs a timing signal. The drive unit 27 receives the timing signal and outputs a drive signal shown in FIG. By performing such control, the output VR-S shown in FIG. 9 is output, and the phase voltage half-wave O
By viewing the total period of N times and OFF times as a cycle, the effective voltage can be output at an arbitrary ratio from zero voltage to the power supply voltage.

In the case of single-phase control, the configuration shown in FIG. 8 is realized by performing the same control as in the case of three-phase control for one triac. However, the selection of the timing is based not on the phase voltage but on the inter-phase voltage.
The conventional voltage regulator is configured as described above, and has been realized with a simple circuit configuration for a desired output effective voltage (ratio) request. In particular, in the case of duty control, the voltage applied to the load during the ON period becomes sinusoidal, and
Since the N timing is 0 voltage and the OFF timing is 0 current, no distortion current is generated, and magnetic noise and noise can be suppressed.

[0008]

The conventional phase control type voltage regulator has the following problems because it is configured as described above. Although it can handle both single-phase and three-phase power supplies, the generation of magnetic noise sometimes causes a problem in use environment. Further, in the duty control method, the problem of magnetic noise and noise is suppressed, but when applied to a three-phase power supply, voltage imbalance and current distortion between phases occur due to selection of ON / OFF timing. Therefore, the concept of control was not established. This specific case will be described. FIG. 10 is a timing chart showing the operation of a conventional three-phase voltage regulator using a duty control method. In FIG. 10, the drive timing of the three-phase triac is when the RS-phase voltage is zero voltage. In this case, the output voltages at the time of the triac drive are the output VR-S, the output VS-T, and the output V shown in FIG.
The output voltage changes abruptly at the time of triac driving, and the current flowing through each phase also includes a high-frequency component as shown in FIG. Looking at the timing of turning off the gate signal of the triac, the gate signal is turned off at the timing when the RS phase voltage is zero in FIG. In this case, since the triac is extinguished at the time when the current becomes zero, the triac is turned off at the timing shown in the same figure, and the conduction state of the S and T phases continues longer than the R phase. That is, IR shown in FIG.
Unbalance occurs in the phase current as in IS and IT. In each of the three phases, the phase current of the triac during the conduction period is proportional to the phase voltage, and the phase current corresponding to the triac in the conduction state of only the two phases is proportional to the inter-phase voltage in the conduction state. Therefore, when the R-phase triac is extinguished, the S and T-phase currents contain harmonics and are out of phase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. When the value of the effective voltage is adjusted and controlled from a three-phase power supply, the positive and negative balance of the conduction period of each phase is maintained, and An object of the present invention is to provide a three-phase voltage regulator capable of suppressing magnetic noise by suppressing excitation.

[0010]

In a three-phase voltage regulator according to the present invention, switching means provided for each phase between a three-phase power supply and a load to open and close a load current, and a voltage between phases of the three-phase power supply are provided. Zero-cross detection means for detecting zero voltage, time-measuring means for measuring time starting from the detection timing of the zero-cross detection means, pattern storage means for storing a pattern of opening / closing timing of the opening / closing means, and a pattern for selecting a required pattern from the pattern storage means Selecting means, timing generating means for inputting the outputs of the zero-cross detecting means and the timing means in accordance with the required pattern and outputting a signal for instructing opening and closing of the opening and closing means, and controlling the opening and closing of the opening and closing means by inputting this signal When the switching means is closed, the timing generation means corresponds to an arbitrary phase voltage at the time of zero voltage. A first closing signal for closing the opening / closing means provided in the two phases is output, and the opening / closing means provided in the remaining phases are closed when the electrical angle is advanced by 90 degrees from the output time of the first closing signal. When the second closing signal is output and the opening / closing means is opened, the output of the first and second closing signals is stopped when an arbitrary phase voltage is substantially zero voltage.

In the three-phase voltage regulator according to the present invention, the timing generating means outputs the output of the first closing signal a predetermined time before an arbitrary inter-phase voltage becomes zero voltage.

In the three-phase voltage regulator according to the present invention, the timing generation means sets the electrical angle from the output of the first closing signal to the stop of the output of the first and second closing signals of 360 degrees. * A + 30 degrees (a is a natural number).

In the three-phase voltage adjusting apparatus according to the present invention, the timing generating means sets the electrical angle from when the output of the first and second closing signals is stopped to when the first closing signal is output to 360 degrees. * B-150 degrees (b is a natural number).

In the three-phase voltage regulator according to the present invention, the timing generation means sets the electrical angle from when the output of the first and second closing signals is stopped to when the first closing signal is output to 360 degrees. * C-90 degrees (c is a natural number).

In the three-phase voltage adjusting apparatus according to the present invention, the timing generating means outputs the first closing signal and stops the output of the first and second closing signals for three cycles.
This is repeated n times (n is a natural number).

In the three-phase voltage regulator according to the present invention, the timing generation means outputs the first closing signal and stops the output of the first and second closing signals in six cycles.
This is repeated n times (n is a natural number).

In the three-phase voltage regulator according to the present invention, the timing generating means outputs a signal for closing all the switching means for a predetermined time before outputting a predetermined effective voltage to the load. It is.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, an example according to Embodiment 1 of the present invention will be described. FIG. 1 is a configuration diagram showing a three-phase voltage regulator according to Embodiment 1 of the present invention. In FIG. 1, components denoted by the same reference numerals as those in FIG. In the figure, 8 is a pattern storage means for storing a phase control pattern, 9 is a pattern selection means for selecting and extracting a required phase control pattern from the pattern storage means 8, and 10 is a detection timing of the zero-cross detection circuit 6 and a timing means 7 Timing generating means for calculating the opening / closing control timing of each triac 3 to 5 based on the time measurement and the selection of the pattern selecting means 9 and outputting a drive signal for each triac 3 to 5; Drive means for supplying a drive signal to each of the triacs 3 to 5 accordingly.

Next, the operation of the three-phase voltage regulator according to Embodiment 1 will be described with reference to the drawings. FIG. 2 is a timing chart showing the operation of the three-phase voltage regulator according to the first embodiment of the present invention, and FIG. 3 is an explanatory diagram of the operation of the three-phase voltage regulator according to the first embodiment of the present invention. . The pattern selection means 9 selects a phase control pattern for opening and closing the triacs 3 to 5 stored in advance in the pattern storage means 8 in accordance with the ratio of the desired output effective voltage to the power supply voltage. Here, when the timing generator 10 closes (turns on) the triacs 3 to 5 based on the selection of the pattern selector 9,
The timing of closing is defined as the time when the arbitrary inter-phase voltage is zero voltage,
A first closing signal for closing the two-phase triac provided in the phase corresponding to the inter-phase voltage is output, and when the two-phase triac is closed, the remaining phase is advanced by 90 degrees in electrical angle. A second closing signal for closing the triac is output to the driving means. In the example of FIG. 2, the timing generation means 10 determines the time T during which the RS phase voltage is zero.
1 outputs a first closing signal for closing the triacs 3 and 4 provided for the R and S phases, and a second closing signal for closing the T-phase triac 5 at a time T2 advanced by 90 electrical degrees. Is output to the driving means 11 (this point is called a closing point). Next, when the triacs 3 to 5 are opened, the timing generation means 10 sets an arbitrary phase voltage (phase voltage is delayed by 30 degrees with respect to the inter-phase voltage: ex. (At 30 degrees later), the output of the first and second closing signals to the driving means is stopped to turn off the driving signals of the triacs 3 to 5 at the time of the zero voltage (this time T
The time point 1 is referred to as an open circuit time point). In the example of FIG. 2,
In order to turn off the drive signals of the triacs 3 to 5 at time T3 when the R phase is at zero voltage, the first and second drive units are turned off.
The output of the closing signal of is stopped.

In the example of FIG. 2, the triacs 3, 4 provided in the R and S phases at time T1 when the voltage of the RS phase is zero.
Is closed for a predetermined period of time (4 electrical degrees) from time T1.
Time corresponding to 0 to 50 degrees) Early triac 3, 4
When the induction motor is used as a load, the torque at the time of energization increases when the load is applied to the induction motor, and the motor loses power.
It has been confirmed by experiments that the generation of such an impact sound is suppressed, and the above-mentioned predetermined time can be appropriately set by a trade-off with magnetic noise. Also,
When the output of the first and second closing signals to the driving means is stopped to turn off the drive signals of the triacs 3 to 5 at the time when the arbitrary phase voltage becomes zero voltage, the phase voltage becomes zero voltage. If it is on the near side, a slight error in the timing of turning off the gate signal is allowed. This is a response to the fact that if the gate signal is released while the current is at the desired polarity, the timing of current interruption will be the same because of the commutation extinction as a characteristic of the triac. Indicates that it is not required.

The storage pattern of the pattern storage means 8 is such that the electrical angle between the time of closing and the time of opening is 360 degrees * a + 30.
Degrees (a is a natural number), and the electrical angle from the time of opening to the time of closing is 360 degrees * b-150 degrees (b is a natural number),
These are pre-selected and are determined using a and b as variables with respect to the required output voltage effective value. FIG.
4 shows an output example of each phase voltage when = 1 and b = 1.

By controlling in this way, the output of the inter-phase voltage becomes the output VR-S output VS-T output VT- shown in FIG.
As shown in S, when the variable a is increased and the variable b is decreased, the effective output voltage is increased. In the opposite case, the effective output voltage is decreased. Therefore, by selecting the variables a and b, the effective output voltage is reduced from zero to the power supply. It can output at any ratio up to the voltage. As shown in FIG. 2, when looking at the timings of the closing of the triacs 3 to 5, the closing timing of the R and S phases is when the voltage between the RS phases is zero, and the closing timing of the T phase is that when the T phase voltage is This is the timing of zero voltage. That is, the circuit is closed at the timing when the potential difference between both ends of each triac is zero voltage. In this way, each phase current rises smoothly from zero amperes. Looking at the timing at the time of opening, the current is cut off when the current is zero amperes due to the commutation arc extinguishing element, so that the deviation of the current cutoff of each triac is within 90 degrees in electrical angle. Since the drive signal of the triac 3 is turned off when the R-phase voltage is zero, the R-phase load current becomes zero amps immediately after the drive signal is turned off, and the R-phase triac 3 becomes non-conductive. The remaining S and T phase triacs 4 and 5 are S-
Conduction is performed based on the voltage between the T phases, but at the time when the voltage between the ST phases becomes zero voltage, the electrical angle becomes 9 after the R phase voltage becomes zero voltage.
This is because it is the time point when 0 degrees have elapsed.

By defining the period between the closing time and the opening time as in this embodiment, each of the triacs 3 to
The conduction period of No. 5 is a period in which the polarity is substantially the same as that of the positive and negative polarities, DC excitation by the inductive load is suppressed, and the mutual conduction period difference between the triacs falls within 90 degrees in electrical angle. Also, by defining the combination of the closing time and the opening time as in the first embodiment, the phases that are the starting points at the closing time are sequentially switched as shown in FIG. For this reason,
By controlling 3n (n is a natural number) times as one group in the same pattern, the balance of the voltage and current of each phase is maintained. Although the same pattern of the variables a and b has been described as one repetition pattern as the storage pattern of the pattern storage means, it is possible to apply a combination of different variables a and b and repeat them sequentially as one pattern. It is.

Further, by employing this embodiment, the following problem may occur when a motor load is applied. The rotation direction is not fixed when the motor starts. If the selected output effective voltage is small, the starting torque is insufficient. To deal with these, the pattern storage means 8
In the case where the motor is started, a start pattern is provided in which all the three-phase triacs 3 to 5 are simultaneously turned on during the start time. By selecting a start pattern at the time of starting the motor and selecting a pattern so that a required effective voltage is obtained after the start of the motor is completed, the initial rotation direction at the time of starting the motor and the starting torque can be secured.

As described above, when the three-phase voltage regulator is configured, the effective output voltage can be arbitrarily adjusted within the range from zero voltage to the power supply voltage by selecting the drive patterns of the triacs 3 to 5. In addition, the timing at the time of closing the triac is when the potential at both ends of the triac is zero voltage,
Magnetic noise and noise can be suppressed. Further, the positive / negative balance of the conduction period of each triac is maintained, the DC excitation of the inductive load can be suppressed, and the difference in the circulation period of each triac is suppressed to 90 degrees in electrical angle to maintain the balance. Further, by selecting the number of repetitions of the combination of the closing time and the opening time, the balance between the energizing period and the non-energizing period of each phase is maintained, and the distortion of each phase current is suppressed.

Embodiment 2 FIG. Next, an example of the three-phase voltage regulator according to Embodiment 2 will be described. FIG. 4 is a configuration diagram showing a three-phase voltage regulator according to Embodiment 2 of the present invention. In the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts, and thus description thereof will be omitted. Reference numeral 12 denotes a pattern storage means, which is different from the pattern storage means of the three-phase voltage regulator shown in FIG. 1 in the stored phase control pattern. FIG. 5 is an explanatory diagram of the operation of the three-phase voltage regulator according to Embodiment 2 of the present invention.

Next, the operation of the three-phase voltage regulator according to the second embodiment will be described. The storage pattern of the pattern storage unit 12 is such that the electrical angle between the time of closing and the time of opening is 360 degrees *
a + 30 degrees (a is a natural number), and the electrical angle from the time of opening to the time of closing is 360 degrees * c-90 degrees (c is a natural number). a and c are selected. The control operation is the same except that the electrical angle between the time of opening and the time of closing is increased. As shown in FIG. 5, in the state of the repetition of the control, the phases which are the starting points at the time of closing the circuit are switched in order, and the order is repeated six times. Therefore, the number of pattern repetitions for maintaining the balance between conduction and non-conduction of the voltage and current of each phase is 6n (n is a natural number) times from 3n times in the first embodiment.

[0028]

Since the present invention is configured as described above, it has the following effects.

According to the present invention, when the timing generating means closes the switching means for opening and closing the load current provided in each phase between the three-phase power supply and the load, the three-phase voltage regulator can be connected to an arbitrary inter-phase voltage. Outputs a first closing signal for closing the switching means provided in the two phases corresponding to the phase at the time of zero voltage,
At the time when the electrical angle is advanced by 90 degrees from the output time of the first closing signal, a second closing signal for closing the opening and closing means provided in the remaining phase is output, and when the opening and closing means is opened, any arbitrary When the output of the first and second closing signals is stopped when the phase voltage is substantially zero voltage, the output effective voltage can be arbitrarily adjusted in a range from zero voltage to the power supply voltage, and when the switching means is closed. Is the timing at which the potentials at both ends of the opening / closing means are at zero voltage, which has the effect of suppressing magnetic noise and noise.

According to the present invention, when the three-phase voltage adjusting device is configured such that the timing generating means outputs the first closing signal before a predetermined time when an arbitrary inter-phase voltage becomes zero voltage, the induction motor When a load is applied, the torque at the time of energization increases, and the effect of suppressing the noise generated from the motor can be achieved.

According to the present invention, the three-phase voltage adjusting device may be configured so that the timing generating means sets the electrical angle from when the first closing signal is output to when the output of the first and second closing signals is stopped to three.
If 60 degrees * a + 30 degrees (a is a natural number), the difference in the circulation period of each opening / closing means is suppressed to 90 degrees in electrical angle, and the effect of maintaining the balance is achieved.

According to the present invention, the three-phase voltage adjusting device may be configured such that the timing generating means sets the electrical angle from when the output of the first and second closing signals is stopped to when the first closing signal is output to three.
Assuming that 60 degrees * b-150 degrees (b is a natural number), the phases that are the starting points at the time of closing are switched in order, and three times are in order, so that 3n (n is a natural number) times are controlled as one group and controlled in the same pattern. By doing so, there is an effect that the balance as the voltage and current of each phase is maintained.

According to the present invention, the three-phase voltage adjusting device may be configured such that the timing generation means sets the electrical angle from when the output of the first and second closing signals is stopped to when the first closing signal is output to three.
If 60 degrees * c-90 degrees (c is a natural number), the phases that are the starting points at the time of closing are switched in order, and 6 times are in order, so that 6n (n is a natural number) times are controlled as one group and controlled in the same pattern. By doing so, there is an effect that the balance as the voltage and current of each phase is maintained.

According to the present invention, in the three-phase voltage adjusting apparatus, the timing generating means outputs a first closing signal and stops outputting the first and second closing signals by 3n (n is a natural number). When the current is repeated twice, the balance between the energizing period and the non-energizing period of each phase is maintained, and the effect of suppressing the distortion of each phase current is achieved.

According to the present invention, in the three-phase voltage regulator, the timing generation means outputs a first closing signal and stops the output of the first and second closing signals by 6n (n is a natural number). When the current is repeated twice, the balance between the energizing period and the non-energizing period of each phase is maintained, and the effect of suppressing the distortion of each phase current is achieved.

According to the present invention, the three-phase voltage adjusting device is arranged so that the timing generating means outputs a signal for closing all the open / close means for a predetermined time before outputting a predetermined effective voltage to the load. Accordingly, there is an effect that the initial rotation direction at the time of starting the motor can be determined and the starting torque can be secured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a three-phase voltage regulator according to Embodiment 1 of the present invention.

FIG. 2 is a timing chart showing an operation of the three-phase voltage regulator according to Embodiment 1 of the present invention.

FIG. 3 is an explanatory diagram of an operation of the three-phase voltage regulator according to Embodiment 1 of the present invention.

FIG. 4 is a configuration diagram showing a three-phase voltage regulator according to Embodiment 2 of the present invention.

FIG. 5 is an explanatory diagram of an operation of the three-phase voltage regulator according to Embodiment 2 of the present invention.

FIG. 6 is a configuration diagram showing a conventional three-phase voltage regulator.

FIG. 7 is a timing chart showing the operation of a conventional three-phase voltage regulator.

FIG. 8 is a configuration diagram showing a conventional single-phase voltage regulator.

FIG. 9 is a timing chart showing the operation of a conventional single-phase voltage regulator.

FIG. 10 is a timing chart showing the operation of a conventional three-phase voltage regulator using a duty control method.

[Explanation of symbols]

1 three-phase power supply, 2 loads, 3-5 switching means, 6 zero-cross detection means, 7 timekeeping means, 8 pattern storage means,
9 pattern selection means, 10 timing generation means, 1
1 Drive means.

Claims (8)

[Claims] An opening / closing means provided in each phase between a three-phase power supply and a load to open and close a load current; a zero-cross detection means for detecting a zero voltage of an inter-phase voltage of the three-phase power supply; Clocking means for measuring the time from the detection timing, pattern storing means for storing a pattern of the opening / closing timing of the opening / closing means, pattern selecting means for selecting a required pattern from the pattern storing means, and zero crossing according to the required pattern Timing output means for inputting the output of the detection means and the timing means and outputting a signal instructing the opening and closing of the opening and closing means, and driving means for inputting the signal and controlling the opening and closing of the opening and closing means,
When closing the switching means, the timing generation means outputs a first closing signal for closing the switching means provided in the two phases corresponding to the inter-phase voltage when an arbitrary inter-phase voltage is zero voltage. At the time when the electrical angle is advanced by 90 degrees from the output time of the first closing signal, a second closing signal for closing the opening and closing means provided in the remaining phase is output, and the opening and closing means is opened. A three-phase voltage regulator that stops outputting the first and second closing signals when an arbitrary phase voltage is substantially zero voltage. 2. The three-phase voltage adjusting device according to claim 1, wherein the timing generation means outputs the output of the first closing signal a predetermined time before an arbitrary inter-phase voltage becomes zero voltage. . 3. The timing generation means sets the electrical angle from when the first closing signal is output to when the output of the first and second closing signals is stopped to 360 degrees * a + 30 degrees (a is a natural number). The three-phase voltage regulator according to claim 1 or 2, wherein: 4. The timing generating means sets the electrical angle from when the output of the first and second closing signals is stopped to the time when the first closing signal is output to 360 degrees * b-150 degrees (b is a natural number).
The three-phase voltage regulator according to claim 3, wherein 5. The timing generation means sets the electrical angle from when the output of the first and second closing signals is stopped to the time when the first closing signal is output to 360 degrees * c-90 degrees (c is a natural number). The three-phase voltage regulator according to claim 3, wherein 6. The timing generating means repeats a cycle of outputting a first closing signal and stopping output of the first and second closing signals 3n times (n is a natural number). 3. The three-phase voltage regulator according to claim 1. 7. The timing generating means repeats a cycle of outputting the first closing signal and stopping the output of the first and second closing signals 6n times (n is a natural number) times. 3. The three-phase voltage regulator according to claim 1. 8. The timing generating means outputs a signal for closing all open / close means for a predetermined time before outputting a predetermined effective voltage to a load.
3. The three-phase voltage regulator according to claim 1.