JP4399405B2 - AC voltage controller using phase advance current - Google Patents

Description

  The present invention relates to an AC voltage control device for controlling a load voltage by connecting in series to an electric circuit and changing a current power factor in a phase advance direction.

  In power transmission systems, phase-advanced power adjustment using the series capacitor method has been used for some time, but there are problems such as high-order and low-order resonance phenomena, and abnormal voltage when shut off. In the phase advance power adjustment device, as the capacity of a semiconductor switch such as a thyristor is increased, a thyristor AC switch is used to perform capacitor bank control and on-timing delayed phase control with respect to an AC reactor. These are called a static reactive power compensator SVC (Static Var Compensator) connected in parallel to a power source and are often used in power systems.

A phase-advancing capacitor, also called a power capacitor, is a film capacitor, but has a long life, a large size, and is expensive. If the phase-advancing capacitor can be replaced with an electrolytic capacitor, it will be small and inexpensive. Although it is known that two diodes can be used in reverse series in parallel with an electrolytic capacitor, it can be used as an AC capacitor. However, there is a proposal to use an electrolytic capacitor by switching with a semiconductor switch (see Patent Document 1). . In Patent Document 1, the polarity problem of the electrolytic capacitor is solved by using four switches.
However, if only the purpose of simply utilizing electrolytic capacitors, the use of those connected in parallel diodes and electrolytic capacitors two anti-series connected to, raised the same effect as the invention disclosed in Patent Document 1 Rukoto is Ru can.

On the other hand, as circuit technology , a current forward / reverse bidirectional current switch that regenerates snubber energy is used to recover the snubber energy generated in the switching element in the capacitor when the load current is cut off , and regenerate to the load at the next turn-on. A loss current forward / reverse bidirectional current switch has been proposed (see Patent Document 2).
Furthermore, this can be connected in series between the AC power source and the load to regenerate not only the snubber energy but also the magnetic energy of the load. The current direction of the switching phase of each half cycle of the AC power supply, also the power factor of the current if the control to advance 90 degrees from the AC power supply can be automatically improved substantially 1, proposed by the present inventors (See Patent Document 3). However, as a result of improved power factor approximately 1, the output at the load voltage rises above the power supply voltage is increased, depending on the load also damage the load becomes increased voltage overvoltage input voltage I needed a transformer to lower it.
JP 7-104872 A Japanese Patent No. 3634982 JP 2004-260991 A

Conventionally, to control the voltage of the AC load, thyristor can be controlled to be turned on is delayed with respect to change in the voltage phase, a method of delaying the current phase in the AC switch such as a triac is common. In control of the triac on, although it is controlled in a direction to lower the load voltage at a delay of the voltage phase and current phase also delayed in accordance with lowering the load voltage, a drawback power factor may turn poor.
In Patent Document 1, for the purpose of miniaturization, only the four semiconductor switches are switched synchronously using an electrolytic capacitor, and the current phase-advance control and control so that the load voltage becomes the target value are positively performed. Can't do it.
As discussed above, and phase advancing capacitor in series connection, such as magnetic energy recovery current bidirectional switch of Patent Document 2, by carrying out the improvement of the lagging power factor load is serial control by the phase advance operation, the load voltage is the power supply voltage Than to rise. However, as it to become overvoltage or overpower, either by stepping down a power supply voltage using a transformer, it is necessary to increase the voltage rating of the load.

Therefore, the present inventor performs control to positively advance the phase of the load current, lowers the voltage applied to the load as the advance power factor, and delay power factor that flows to other AC loads that are not subjected to reactive power compensation measures. It was noticed that the power factor could be improved as a whole if the current of the current and the current of the above-described advance power factor were combined.
The present invention has been made in view of the circumstances as described above, and provides an AC voltage control device that can control the load voltage of each load while improving the power factor of the entire system. Objective.

The present invention relates to an AC voltage control device that is inserted between an AC power supply and an AC load and controls a load voltage applied to the AC load. The object of the present invention is composed of four reverse conducting semiconductor switches. Phase control that controls on / off of a reverse conduction type semiconductor switch and a magnetic energy regenerative bidirectional current switch composed of a bridge circuit connected between the DC terminals of the bridge circuit and a capacitor that regenerates the magnetic energy of the AC load And a power factor meter for measuring a power factor of a power supply current connected in series to an AC power source, wherein the phase control device includes two reverse conducting semiconductor switches located on a diagonal line of the bridge circuit And control to turn off the other pair when one of the two pairs of reverse conducting semiconductor switches is on,
In addition, by controlling on / off of the reverse conducting semiconductor switch so as to forcibly advance the phase of the current, a voltage that compensates the reactance voltage of the AC load is generated in the capacitor, and the load applied to the AC load The voltage is controlled and the phase is advanced by the magnetic energy regenerative bidirectional current switch and the current of the delayed power factor that flows to other AC loads connected in parallel to the AC power supply without going through the magnetic energy regenerative bidirectional current switch. The phase controller is fed back to the output of the power factor meter so that the power factor of the power source current becomes approximately 1 as a whole, together with the current of the leading power factor flowing through the AC load, and the phase control device This is achieved by an AC voltage controller characterized by controlling on / off.

The above-mentioned object of the present invention is also achieved by an AC voltage control device characterized in that the capacitance of the capacitor is a capacitance that only absorbs the magnetic energy of the AC load.
Furthermore, the above object of the present invention is characterized in that the capacitance of the capacitor is set to a value such that the resonance frequency determined by the capacitor and the inductance of the AC load is higher than the power frequency of the AC power source. This is also achieved by a voltage control device.
The above-described object of the present invention, two sets of which are connected in parallel a capacitor and a reverse conducting semiconductor switches, connect the cathode side ends of the switching elements constituting the reverse conducting semiconductor switches (hereinafter, "anti-series connection" called.) There was a second capacitor lateral half-bridge arrangement, and second capacitor lateral half-bridge magnetic energy recovery bidirectional current switch, and a phase controller for controlling the reverse conducting semiconductor switch on / off, in series to an AC power source A power factor meter that measures the power factor of the power supply current, and the capacitance of each capacitor has a resonance frequency determined by the capacitance of each capacitor and the inductance of the AC load. In addition, the phase control device has two anti-conducting elements connected in reverse series. By controlling one of the type semiconductor switches to turn off when one is on, and controlling the on / off of the reverse conduction type semiconductor switch to forcibly advance the current phase, A voltage that compensates for the reactance voltage of the AC load is generated in the capacitor of the AC load, the load voltage applied to the AC load is controlled, and further, the AC power supply is not connected via the two-capacitor horizontal half-bridge magnetic energy regenerative bidirectional current switch. Combine the current of the delayed power factor that flows to other AC loads connected in parallel with the current of the leading power factor that flows to the AC load whose phase has been advanced by the two-capacitor horizontal half-bridge magnetic energy regenerative bidirectional current switch, The phase control device is a reverse-conducting semiconductor by feeding back the output of the power factor meter so that the power factor of the power supply current becomes approximately 1 as a whole. Also achieved by an alternating voltage control unit and controls the switch on / off.
Further, the above object of the present invention is to provide a parallel connection of a circuit in which two anodes of two sets of diodes are connected in parallel with a capacitor and a diode, and a circuit in which two reverse conducting semiconductor switches are connected in reverse series. connected to, 2 capacitors was horizontal half-bridge configuration, 2 capacitors and horizontal half-bridge magnetic energy recovery bidirectional current switch, and a phase controller for controlling the reverse conducting semiconductor switch on / off, in series with the AC power source A power factor meter that measures the power factor of the power supply current, and the capacitance of each capacitor has a resonance frequency determined by the capacitance of each capacitor and the inductance of the AC load of the AC power source. In addition to being set to a value higher than the power supply frequency, the phase control device further comprises two reverse conducting semiconductors connected in reverse series. When one of the switches is on, the other is controlled to turn off, and the reverse conduction type semiconductor switch is controlled to turn on / off so as to forcibly advance the current phase. To generate a voltage that compensates for the reactance voltage of the AC load, to control the load voltage applied to the AC load, and in parallel to the AC power supply without going through the two-capacitor horizontal half-bridge magnetic energy regenerative bidirectional current switch Combine the current of the delayed power factor that flows to the other connected AC load and the current of the power factor that flows to the AC load whose phase is advanced by the two-capacitor horizontal half-bridge magnetic energy regenerative bidirectional current switch. The phase control device is a reverse conduction type semiconductor switch by feeding back the output of the power factor meter so that the power factor of the power supply current is approximately 1. Also achieved by an AC voltage control device and controls the on / off.

Furthermore, the above object of the present invention is also achieved by an AC voltage control device characterized in that the capacitor is an electrolytic capacitor.
Another object of the present invention is to provide a one-capacitor lateral half-bridge magnetic energy regenerative bidirectional current comprising a capacitor and a circuit connected in parallel to the capacitor and connected in reverse series with two reverse conducting semiconductor switches. a switch, and a phase controller for controlling the reverse conducting semiconductor switch on / off, connected in series to an AC power source, comprising a power factor meter for measuring the power factor of the power supply current, the capacitance of the capacitor Is set to a value such that the resonance frequency determined by the capacitance of the capacitor and the inductance of the AC load is higher than the power supply frequency of the AC power supply, and two phase control devices are connected in reverse series. Of the reverse conduction type semiconductor switches, when one is on, the other is turned off and the reverse conduction type semiconductor is forced to advance the phase of the current. By controlling the on / off of the switch, the capacitor generates a voltage that compensates for the reactance voltage of the AC load, controls the load voltage applied to the AC load, and in addition, both one-capacitor horizontal half-bridge magnetic energy regeneration The current of the delay power factor that flows to another AC load connected in parallel to the AC power supply without going through the directional current switch and the AC load whose phase is advanced by the one-capacitor horizontal half-bridge magnetic energy regenerative bidirectional current switch The phase control device controls on / off of the reverse conduction type semiconductor switch by feeding back the output of the power factor meter so that the power factor of the power source current as a whole becomes approximately 1 together with the current of the leading power factor. This is also achieved by an AC voltage control device characterized by this.
Another object of the present invention is to provide an AC power supply pressure control characterized in that a switching element that can be turned off, such as a power MOSFET, IGBT, or GTO, is used as a self-extinguishing element constituting each reverse conducting semiconductor switch. It is also achieved by the device.

If the AC voltage control device according to the present invention is connected in series between an AC power source and an AC load, and the reverse conduction type semiconductor switch in the AC voltage control device is turned on / off in the leading phase, the load current is reduced. It can be a phase advance current. Further, by increasing the phase of the load current, a voltage that is lower than the power supply voltage can be applied to the load, and the phase-advancing reactive power adjustment device is obtained.

Further, according to the AC voltage control apparatus of the present invention, the capacity of the capacitor may be a capacity that can absorb the magnetic energy of the load, and a DC electrolytic capacitor can be used. For this reason, it can contribute to cost reduction.
Furthermore, because the phase advance current improves the power factor of other power loads that are not adjusted for reactive power, using this phase advance power adjustment device not only allows voltage adjustment, but also has the same function as a phase advance capacitor. As a result, the input current is reduced, which can contribute to energy saving and power capacity reduction in the distribution line .

Hereinafter, an AC voltage control apparatus according to the present invention will be described in detail with reference to the drawings.
Further, hereinafter, to turn on / off the reverse conducting semiconductor switch is to bring the self-extinguishing element constituting the reverse conducting semiconductor switch into a conducting / blocking state. Even if the self-extinguishing element is blocked, current in the reverse direction of the self-extinguishing element can always be conducted because of the diode connected in antiparallel.
FIG. 1 is a diagram for explaining an AC voltage control apparatus according to the present invention and a control mechanism for making the power factor of the entire system approximately 1 by using the AC voltage control apparatus.
In FIG. 1, a power factor meter 5 is connected in series to the AC power source 1 to measure the power factor of the power source current and to send a feedback signal to a phase control device 4 described later. Power factor meter 5, four in the power MOSFET, and a self-extinguishing element that can of turning on / off of such IGBT, the reverse conducting semiconductor switch 21 consisting of antiparallel connected diodes (SW1 to SW4) One AC of a magnetic energy regenerative bidirectional current switch 2 comprising a bridge circuit configured as described above and a capacitor 22 connected between the DC terminals DCP and DCN of the bridge circuit and accumulating and regenerating the magnetic energy of the AC load 3a. It is connected to the terminal AC1 .
The phase control unit 4, of the four reverse conducting semiconductor switches 21, two reverse conducting semiconductor switches positioned on a diagonal line of the bridge circuit and (SW1, SW3) and (SW2, SW4), respectively a set Of the two pairs of reverse conducting semiconductor switches, when one pair is on, the other pair is controlled to be turned off, and the pair is set every half cycle of the AC power supply 1. A gate signal for alternately turning on / off in units is generated. The phase controller 4 detects the phase of the voltage of the AC power supply 1 and advances the phase so that the output of the power factor meter approaches 1.

If the AC voltage control device according to the present invention is connected in series between an AC power source and an AC load and turned on / off at a leading phase, a reactive voltage with a leading power factor can be generated. That is, if the AC voltage control device according to the present invention is connected in series with the power supply voltage , the load current can be made to advance.

In FIG. 1, without the intervention of the magnetic energy recovery bidirectional current switch 2, AC load 3b connected in parallel to the AC power source 1 is present. Since the reactive power is not adjusted for the AC load 3b , the current has a delay power factor. Therefore, by combining the current of the leading power factor flowing through the AC load 3a and the current of the delay power factor of the AC load 3b, the current having a power factor of approximately 1 can be obtained as a whole . That is, to connect the upper predicate magnetic energy recovery bidirectional current switch 2 of the AC load of about half that present in the circuit, the AC load for the remaining about half by connecting directly to an AC power source, while suppressing the load voltage, The power factor of the current can be improved as a whole circuit.

FIGS. 7 (a) through FIG. 7 (c) shows a phasor diagram of the voltages.
More specifically, FIG. 7 (c), an AC voltage control apparatus according to the present invention, generates a reactance voltage Vc of phase advancing, the voltage V load was reduced than power supply voltage Vin, is applied to the AC load 3a It is also shown that it can be a phase advance power adjustment device.
FIG. 7A shows a phasor diagram of the AC load 3 b that is not connected to the magnetic energy regeneration bidirectional current switch 2 . The load current Iload has a delay power factor cosφ.
FIG. 7 (b), the AC load 3a connected to the magnetic energy recovery bidirectional current switch 2 shows a case where the current power factor of Ri AC load 3a by the phase control unit 4 is controlled so as to be approximately 1 ing.
As can be seen from FIG. 7B, the inductance voltage V load of the AC load 3 a is completely compensated by the reactance voltage Vc of the capacitor 22. Result, the load voltage V load is equal to the voltage Vin of the AC power source 1, it is not possible to lower the load voltage Vload.
FIG. 7 (c), from the state of FIG. 7 (b), further advancing the phase of the current shows a case where the current power factor of the AC load 3a, was leading power factor cos [phi. 7C , the load voltage Vload is lowered, and the power factor is made substantially 1 as a whole together with the current of the delayed power factor shown in FIG. It is feasible to lower V load .

In the AC voltage control device according to the present invention, the reactance voltage Vc advanced by 90 degrees from the load current I is generated. Therefore , no external power supply is required to charge the capacitor 22, and the voltage is automatically applied to the capacitor 22. appear. The capacitance C of the capacitor 22 may be a degree of capacity to absorb magnetic energy of the AC load 3a, DC electrolytic capacitors can be used. When the capacitance of the capacitor 22 is relatively small, the current of the capacitor 22 is interrupted. That is, the characteristic of the present apparatus is that the voltage of the capacitor 22 becomes substantially zero within the half cycle time of the AC power supply 1 . Since the voltage of the capacitor 22 becomes substantially zero, the AC voltage control apparatus according to the present invention, without calling the conventional voltage-type inverter, Ru Bekidea called a switch.

When the AC voltage control device according to the present invention is used, it is possible to have a voltage control function that is more than that in which the phase-advancing capacitor has a series impedance. The phase advance current is improved by combining the power factor of other power loads, so the current of the transmission and distribution lines is reduced, and energy saving in the distribution lines and the capacity of the power receiving transformer (apparent power capacity) are reduced. To contribute.

The two reverse conducting semiconductor switches located on the diagonal line of the bridge circuit composed of the four reverse conducting semiconductor switches in FIG. 1 are formed as one pair, and two pairs (SW1, SW3) When paying attention to (SW2, SW4) , the two pairs are turned on / off so that when one pair is on, the other pair is turned off at every half power cycle of the AC power supply 1. Switch. However, for example, by turning off the self-turn-off elements constituting the reverse conducting semiconductor switches SW3, current flows through the anti-parallel connected diodes of reverse conducting semiconductor switches SW2, constituting the reverse conducting semiconductor switches SW2 Even if the self-extinguishing element is delayed in on-state, there is no problem in operation. The magnetic energy recovery bidirectional current switch 2, further utilizing a characteristic of above, as described later, when the electrostatic capacitance of the capacitor 22 is relatively small, self-turn constitutes the reverse conducting semiconductor switches SW3 to ON Ru can be an arc-shaped element and unnecessary.

Figure 4 shows the embodiment of a circuit with a simplified portion of the magnetic energy recovery bidirectional current switch 2 in Figure 1. More specifically, FIG. 4 shows two sets of capacitors and reverse conducting semiconductor switches connected in parallel, the cathode side of the self-extinguishing element constituting the reverse conducting semiconductor switch (in FIG. Since the shape element is an N-channel silicon power MOSFET, the source side of the N-channel silicon power MOSFET is connected to each other to form a magnetic energy regenerative bidirectional current switch having a two-capacitor horizontal half bridge configuration. This is possible only under the condition that each capacitor is fully discharged each time within a half cycle of the AC power supply 1 (the voltage across each capacitor becomes approximately 0 [V]) . Specifically, the resonance frequency f determined by the capacitance C of each capacitor and the inductance capacitance L of the AC load 3a is higher than the frequency f0 of the AC power supply 1, and is expressed by the following equation (1). .
f = 1 / 2π√ (LC)> f0 (1)
The magnetic energy regenerative bidirectional current switch of the circuit mode of FIG. 4 is characterized in that it has two capacitors but two reverse conducting semiconductor switches.

FIG. 3 shows a case where the state of the above formula (1) is satisfied. Hereinafter, this will be described in detail with reference to FIG.
When the reverse conducting semiconductor switches SW3 you off (reverse conducting self-turn-off devices the blocking state of the semiconductor switches SW3), current, AC load from the (AC power supply 1 as shown by an arrow shown in FIG. 3 3a orientation) current flowing into the capacitor 22, since the flow through the anti-parallel connected diodes of reverse conducting semiconductor switches SW2, is independent of the state of the on / off reverse conducting semiconductor switch SW2. Circuit capacitor 22 is inserted in series, the capacitance of the capacitor 22 is small, current, charging of the capacitor 22 is terminated at time within one cycle of 4 minutes of the AC power supply 1, further 4 the AC power supply 1 orientation of minute current time within one cycle is discharged reversed, the voltage Vc across the capacitor 22 becomes substantially zero [V]. That is, first, a current flows through the diode connected in reverse parallel of the reverse conducting semiconductor switch SW2, and when the direction of the current is eventually reversed, the self-conversion of the reverse conducting semiconductor switch SW2 that is already on at that time. flow-turn-off device, the voltage Vc across the capacitor 22, Ru flows until substantially zero [V]. Meanwhile, the direction of current does not reverse. Current intermittent Suruga capacitor 22, the current of the capacitor 22, the self-turn-off elements constituting the reverse conducting semiconductor switch or so without also intermittently naturally diode, skip reverse conducting semiconductor switches SW2 It can be seen that it can be replaced with wiring . The direction of the current is opposite to that in FIG. 3 (the current is in the direction from the AC load 3a to the AC power supply 1 and one end of the AC load 3a is connected to the AC terminal AC2-the positive side of the capacitor 22—the negative side of the capacitor 22— In the case of the reverse conducting semiconductor switch SW3—the AC terminal AC1 to which one end of the AC power supply 1 is connected ) , the same operation as described above is performed on the opposite side (reverse conducting semiconductor switches SW1 and SW4) . The case shown in FIG. 3, when extended to deal with bidirectional current, ing and aspects of the circuit shown in FIG.
4, the capacitor 22 of the magnetic energy recovery bidirectional current switch 2 shown in FIG. 1, is divided into two (electrostatic capacitance equal to the condenser 22), the capacitor 23 and the capacitor 24, a half cycle of the AC power supply 1 in order to use (charge and discharge) the alternately every, Ru can Succoth substantially the same function was fruit and magnetic energy recovery bidirectional current switch 2 shown in FIG. Figure 4 is the magnetic energy recovery bidirectional current switch 2 of Figure 1, a capacitor 22 parts, cut laterally (divided in the horizontal direction) corresponds to a half-bridge configuration. However, in the embodiment of the circuit shown in FIG. 4, even if the clear all of the reverse conducting semiconductor switches, it is impossible to cut off the load current, there are restrictions on some functions.

FIG. 5 shows another circuit embodiment of FIG. More specifically, FIG. 5 shows that a capacitor and two reverse conducting semiconductor switches connected in parallel to the capacitor are connected to the cathode side of the switching element constituting the reverse conducting semiconductor switch (in FIG. Since the element is an N-channel silicon power MOSFET, the source side of the N-channel silicon power MOSFET is connected to each other to form a magnetic energy regenerative bidirectional current switch having a one-capacitor lateral half-bridge configuration.
Aspect of the circuit of Figure 5, the two reverse conducting semiconductor switch connected in parallel with the capacitor 22, every time the power supply half cycle of the AC power supply 1, and turns off the other when hand is on as to that, I switched on / off. It can be seen that the control described above controls the function of the capacitor 22 .
Further, FIG. 5 is a dual circuit of a reactive power control device TCR (Thyristor Controlled Reactor) that controls the phase of the reactor current by delaying the on-phase of the thyristor. .

6, instead of the capacitor 22 of FIG. 5, and two capacitors in parallel with each capacitor, to a variant embodiment der added diodes D1 and D2.
Features of Figure 6 is the same as FIG. 5, each of the capacitor for a DC voltage is biased occurs, the DC capacitor Ru can the use Ukoto. The diodes D1 and D2 operate so that no current flows.

FIG. 1 also shows an embodiment of reactive power compensation and load voltage control using an AC voltage control apparatus according to the present invention . A magnetic energy regenerative current bidirectional switch is connected in series between an AC power source and an AC load, and the current is conducted to the reverse conducting semiconductor switch . Four reverse conducting types are provided every half cycle of the AC power source 1. Two reverse conducting semiconductor switches located on a diagonal line of a bridge circuit composed of semiconductor switches are formed as a pair, and the two pairs (SW1, SW3) and (SW2, SW4) are alternating currents. Every half cycle of the power supply 1 is switched on / off so that when one pair is on, the other pair is off.
Signal for switching the ON / OFF (hereinafter, referred to as "gate signals".) (Temporally varied prior to the change of the voltage phase of the AC power source 1) of the advancing phase of that is, Ru generates a leading phase current .
The gate signal is generated by the phase control device 4 by detecting the voltage phase of the AC power supply 1 . Electrically insulated and sent to the gate of the reverse conducting semiconductor switch. In this embodiment , a photorelay driven by an optical signal is used. Gate signal, the first-order lag circuit composed of a resistor connected with the capacitor to the AC power supply 1, Ru made from zero-crossing signal of the power supply voltage. The number of parts is Ru 20 degree and complexity der.

Even if the capacitance reactance Xc of the capacitor 22 is larger or smaller than the reactance Xl of the AC load 3a, an effect is produced . The present invention is characterized in that the capacitor capacity 22 can be reduced. And reactance Xl AC load 3a, the capacitive reactance Xc of the capacitor 22 is the same extent, the voltage waveform applied to the AC load 3a is Ri Do sinusoidal shape, low harmonic Kunar. When the capacitance of the capacitor 22 is small, the voltage Vc across the capacitor 22 tends to increase. The phase of the gate control signal, the control advances (temporally varied prior to the change of the AC power supply 1 voltage phase), the load voltage Vload can be varied to decrease from increase. Ru can be feedback controlled according to the load voltage Vload.

In the embodiment shown in FIG. 1, the following circuit constants are used. The AC load 3a and the AC load 3b are fan motors.
<Circuit constants of FIG. 1>
Rated AC input voltage of AC load 3a and AC load 3b: 100Vrms,
Rated input current of AC load 3a and AC load 3b: 0.21 Arms,
Delay power factor of AC load 3a and AC load 3b : about 0.7 ,
Inductance component L of AC load 3a and AC load 3b : 1H,
AC load 3a and AC load 3b resistor Ingredients R: 333 ohms,
Capacitance of capacitor 22: 2.2 micro F.
In the embodiment shown in FIG. 1, the load current Iload of the AC load 3a is Ri Do the leading power factor 0.7, the load voltage Vload also magnetic energy recovery bidirectional current switch 2 is stabilized at the same voltage as if non Can drive to.

FIG. 8 (a) shows the computer simulation waveforms of the embodiment shown in FIG.
More specifically, FIG. 8A shows the load current of the AC load 3b connected in parallel to the AC power source 1 without passing through the magnetic energy regenerative bidirectional current switch 2 (in FIG. (No switch) ”), the load current of the AC load 3a connected via the magnetic energy regenerative bidirectional current switch 2 (in FIG. 8A,“ load current ”). ), The voltage amplitude of the power supply voltage Vac of the AC power supply 1 is 1/5000 times (indicated as “power supply voltage × 0.005” in FIG. 8A).
The load current (no switch) is a current having a delay power factor of 0.7. In magnetic energy recovery bidirectional current switch 2, 95 °, the phase of the gate control signal, the control advances (temporally varied prior to the change of the AC power supply 1 voltage phase) as a result, FIG. 8 (a ), The load current of the AC load 3a has a leading power factor of 0.7.
The effective value of the load current of the AC load 3a and the load current of the AC load 3b are the same. Resulting distortion of the load current waveform, but since it generates a leading phase current can improve the current power factor of the other AC loads connected to the same system. Furthermore, two units can be obtained by adding the same type of AC load (in this embodiment, AC load 3b) connected in parallel to the AC power source 1 and the input current without passing through the magnetic energy regenerative bidirectional current switch 2. In addition, a power factor of approximately 1 can be realized when viewed from the power transmission end.
Figure 8 (b) to FIG. 8 (d) that shows the computer simulation waveforms of the circuit shown in FIG.
More specifically, FIG. 8B shows the load voltage of the AC load 3c, the voltage Vc1 across the capacitor 23 (indicated as “capacitor voltage 1” in FIG. 8B), and the voltage across the capacitor 24. Vc2 (indicated as “capacitor voltage 2” in FIG. 88B).
FIG. 8C shows a current Ic1 flowing through the capacitor 23 (indicated as “capacitor current 1” in FIG. 8C).
Further, FIG. 8D shows a current Isw3 (indicated as “P-MOSFET current” in FIG. 8D) flowing through the reverse conducting semiconductor switch SW3.

Using the AC voltage control apparatus according to the present invention, it is possible to generate a phase advance current while reducing the voltage of the AC load. Even non-inductive loads such as lamp loads are effective when used with reduced voltage. Since this apparatus lowers the voltage by current advance control, a phase advance current is generated. This helps to improve the overall power factor of the power line.
As an example of a non-inductive load such as a lamp load, the AC load 3a uses an AC power supply 1 with a single-phase 100V, 100W bulb and reduces the required brightness to 70W . Line voltage reduction by controlling the phase advance power factor 0.7 using an alternating current control device according to the present invention UTO, leading current is, 100√ (1-0.7 ²⁾ = about 70VA min, the 0.7A A phase advance current is obtained. The load current, Ri Do a power factor improvement combined with delayed power load other current, the reduction of the Joule loss in power transmission and distribution. In addition, the life of the bulb is extended by reducing the load voltage.

Moreover, it is shown in Figure 1, in the embodiment of the control of reactive power compensation and load voltage using an AC voltage control apparatus according to the present invention, with two lagging power factor cos [phi 1 pair of fan motor (AC load 3a and one of the 3b) and (AC load 3a), are connected via an AC voltage control apparatus according to the present invention.
As the load voltage of the two fan motors have the same voltage, respectively, the phase control unit 4, when advancing the phase of the alternating current load 3a, in the synthesis of the fan motor two current, power factor to approximately 1 that Do not.
The current (input current) supplied from the AC power source 1 is reduced to cosφ times before being improved by the reactive power compensation and the load voltage control using the AC voltage control device according to the present invention . joule loss is reduced.

As in the examples above mentioned, when the power control using an alternating current control device according to the present invention, when adjusting the voltage allows leading phase control of the current. Phase advance amount not possible with conventional static capacitor, a reverse conducting semiconductor switch on / off of the gate signal of the phase, can be controlled continuously and fast, versatile by high-speed control according to the load condition of the equipment Can be applied.

In the above, the width of the ON / OFF has been described in broad half cycle of the power supply period of the AC power supply 1, the case of FIG. 1, by reduction PWM (pulse width modulation), says that can measure harmonics not.
Further, the embodiment describes the application of a single-phase alternating current, expand into the three-phase alternating current is Ru is naturally considered. When applied to a three-phase alternating current, of the harmonics, the third-order harmonics, it is possible to automatically turn off the delta connection.

Further, as a self-turn-off elements constituting the reverse conducting semiconductor switches has been described a power MOSFET as an example, IGBT, GTO, etc., are possible as well if on / off possible switching element.

It is a figure for demonstrating the mechanism of the control which makes the power factor of the whole system | system | group using it the alternating voltage control apparatus which concerns on this invention. It is a figure which shows the relationship between the voltage control by a thyristor AC switch, and a voltage current. It is a figure which shows the flow of an electric current immediately after making reverse conduction type semiconductor switch SW3 into an OFF state . It is a figure which simplifies a magnetic energy regeneration bidirectional | two-way current switch, and shows the structure using a DC capacitor . It is a figure which shows the structure which simplified the magnetic energy regeneration bidirectional | two-way current switch most. In FIG. 4, it is a figure which shows the structure which connected the external diode further to the direct-current capacitor. It is a figure which shows the phasor figure of voltage control. It is a figure which shows the computer simulation waveform of the electric current of an Example, and a voltage.

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Magnetic energy regeneration bidirectional | two-way current switch 3a, 3b, 3c AC load 4 Phase control apparatus 5 Power factor meter 21 Reverse conduction type semiconductor switch 22 , 23, 24 capacitor | condenser
D1, D2 diode

Claims (15)

An AC voltage control device that is inserted between an AC power source and an AC load and controls a load voltage applied to the AC load, the AC voltage control device comprising:
A magnetic energy regenerative bidirectional current switch comprising a bridge circuit composed of four reverse conducting semiconductor switches, and a capacitor connected between the DC terminals of the bridge circuit and regenerating the magnetic energy of the AC load;
A phase controller for controlling an on / off of the reverse conducting semiconductor switches,
A power factor meter connected in series to the AC power source and measuring the power factor of the power source current;
In the phase control device, the two reverse conducting semiconductor switches located on the diagonal line of the bridge circuit form one pair, and one of the two pairs of the reverse conducting semiconductor switches is the pair. Control to turn off the other pair when is on,
In addition, by controlling on / off of the reverse conducting semiconductor switch so as to forcibly advance the phase of the current, a voltage that compensates the reactance voltage of the AC load is generated in the capacitor, and the AC load is Controlling the applied load voltage;
Further, the phase is advanced by the current of the delay power factor flowing through another AC load connected in parallel to the AC power supply without passing through the magnetic energy regeneration bidirectional current switch and the magnetic energy regeneration bidirectional current switch. The phase control device feeds back the output of the power factor meter so that the power factor of the power source current becomes approximately 1 as a whole, together with the current of the leading power factor flowing through the AC load, and the phase control device is connected to the reverse conducting semiconductor. An AC voltage control device for controlling on / off of a switch.   2. The AC voltage control device according to claim 1, wherein the capacitance of the capacitor is a capacitance that only absorbs magnetic energy of the AC load.   The capacitance of the capacitor is set to a value such that a resonance frequency determined by a capacitance of the capacitor and an inductance of the AC load is higher than a power supply frequency of the AC power supply. The AC voltage control device according to 1 or 2. An AC voltage control device that is inserted between an AC power source and an AC load and controls a load voltage applied to the AC load, the AC voltage control device comprising:
Two sets of a capacitor and a reverse conducting semiconductor switches which are connected in parallel, connect the cathode side ends of the switching elements constituting the reverse conducting semiconductor switches (hereinafter, referred to as "anti-series connection".), A two capacitors A two-capacitor horizontal half-bridge magnetic energy regenerative bidirectional current switch in a horizontal half-bridge configuration;
A phase controller for controlling an on / off of the reverse conducting semiconductor switches,
A power factor meter connected in series to the AC power source and measuring the power factor of the power source current;
The capacitance of each capacitor is set to a value such that the resonance frequency determined by the capacitance of each capacitor and the inductance of the AC load is higher than the power supply frequency of the AC power supply,
Further, the phase control device controls so that when one of the two reverse-conducting semiconductor switches connected in reverse series is turned on, the other is turned off, and the phase of the current is forced By controlling on / off of the reverse conducting semiconductor switch so as to proceed, a voltage for compensating the reactance voltage of the AC load is generated in each capacitor, and the load voltage applied to the AC load is Control
Further, a current of a delay power factor flowing through another AC load connected in parallel to the AC power supply without passing through the two-capacitor horizontal half-bridge magnetic energy regeneration bidirectional current switch, and the two-capacitor horizontal half-bridge magnetic energy regeneration The output of the power factor meter is fed back so that the power factor of the power source current becomes approximately 1 as a whole, together with the current of the leading power factor flowing through the AC load whose phase is advanced by the bidirectional current switch. An AC voltage control device, wherein the phase control device controls on / off of the reverse conducting semiconductor switch. An AC voltage control device that is inserted between an AC power source and an AC load and controls a load voltage applied to the AC load, the AC voltage control device comprising:
Two sets of capacitors and diodes connected in parallel, a circuit in which the anode sides of the diodes are connected to each other, and a circuit in which two reverse conducting semiconductor switches are connected in reverse series are connected in parallel to form a two-capacitor horizontal type A two-capacitor horizontal half-bridge magnetic energy regenerative bidirectional current switch in a half-bridge configuration;
A phase controller for controlling an on / off of the reverse conducting semiconductor switches,
A power factor meter connected in series to the AC power source and measuring the power factor of the power source current;
The capacitance of each capacitor is set to a value such that the resonance frequency determined by the capacitance of each capacitor and the inductance of the AC load is higher than the power supply frequency of the AC power supply,
Further, the phase control device performs control so that when one of the two reverse conducting semiconductor switches connected in reverse series is turned on, the other is turned off, and the phase of the current is forcibly set. By controlling on / off of the reverse conducting semiconductor switch so as to proceed, a voltage for compensating the reactance voltage of the AC load is generated in each capacitor, and the load voltage applied to the AC load is Control
Further, a current of a delay power factor flowing through another AC load connected in parallel to the AC power supply without passing through the two-capacitor horizontal half-bridge magnetic energy regeneration bidirectional current switch, and the two-capacitor horizontal half-bridge magnetic energy regeneration The output of the power factor meter is fed back so that the power factor of the power source current becomes approximately 1 as a whole, together with the current of the leading power factor flowing through the AC load whose phase is advanced by the bidirectional current switch. An AC voltage control device, wherein the phase control device controls on / off of the reverse conducting semiconductor switch.   An AC voltage control device that is inserted between an AC power source and an AC load and controls a load voltage applied to the AC load, the AC voltage control device comprising:
  A two-capacitor horizontal half-bridge magnetic energy regenerative bidirectional current switch in which two sets of capacitors and reverse conducting semiconductor switches connected in parallel are connected in reverse series to form a two-capacitor horizontal half-bridge configuration;
  A phase control device for controlling on / off of the reverse conducting semiconductor switch,
  The capacitance of each capacitor is set to a value such that the resonance frequency determined by the capacitance of each capacitor and the inductance of the AC load is higher than the power supply frequency of the AC power supply,
  Further, the phase control device controls so that when one of the two reverse-conducting semiconductor switches connected in reverse series is turned on, the other is turned off, and the phase of the current is forced By controlling on / off of the reverse conducting semiconductor switch so as to proceed, a voltage for compensating the reactance voltage of the AC load is generated in each capacitor, and the load voltage applied to the AC load is An AC voltage controller characterized by controlling.   An AC voltage control device that is inserted between an AC power source and an AC load and controls a load voltage applied to the AC load, the AC voltage control device comprising:
  Two sets of capacitors and diodes connected in parallel, a circuit in which the anode sides of the diodes are connected to each other, and a circuit in which two reverse conducting semiconductor switches are connected in reverse series are connected in parallel to form a two-capacitor horizontal type A two-capacitor horizontal half-bridge magnetic energy regenerative bidirectional current switch in a half-bridge configuration;
  A phase control device for controlling on / off of the reverse conducting semiconductor switch,
  The capacitance of each capacitor is set to a value such that the resonance frequency determined by the capacitance of each capacitor and the inductance of the AC load is higher than the power supply frequency of the AC power supply,
  Further, the phase control device performs control so that when one of the two reverse conducting semiconductor switches connected in reverse series is turned on, the other is turned off, and the phase of the current is forcibly set. By controlling on / off of the reverse conducting semiconductor switch so as to advance, a voltage for compensating the reactance voltage of the AC load is generated in each capacitor, and the load voltage applied to the AC load is An AC voltage controller characterized by controlling. It said capacitor, AC voltage control device according to any one of claims 1 to 7, characterized in that a DC capacitor. An AC voltage control device that is inserted between an AC power source and an AC load and controls a load voltage applied to the AC load, the AC voltage control device comprising:
A one-capacitor horizontal half-bridge magnetic energy regenerative bidirectional current switch composed of a capacitor and a circuit connected in parallel to the capacitor and connected in reverse series with two reverse conducting semiconductor switches;
A phase controller for controlling an on / off of the reverse conducting semiconductor switches,
A power factor meter connected in series to the AC power source and measuring the power factor of the power source current;
The capacitance of the capacitor is set to a value such that the resonance frequency determined by the capacitance of the capacitor and the inductance of the AC load is higher than the power supply frequency of the AC power source,
Further, the phase control device controls so that when one of the two reverse-conducting semiconductor switches connected in reverse series is turned on, the other is turned off, and the phase of the current is forced By controlling on / off of the reverse conducting semiconductor switch so as to proceed, a voltage for compensating the reactance voltage of the AC load is generated in the capacitor, and the load voltage applied to the AC load is controlled. ,
Further, a current of a delay power factor flowing through another AC load connected in parallel to the AC power supply without passing through the one-capacitor horizontal half-bridge magnetic energy regeneration bidirectional current switch, and the one-capacitor horizontal half-bridge magnetic energy regeneration The output of the power factor meter is fed back so that the power factor of the power source current becomes approximately 1 as a whole, together with the current of the leading power factor flowing through the AC load whose phase is advanced by the bidirectional current switch. An AC voltage control device, wherein the phase control device controls on / off of the reverse conducting semiconductor switch.   An AC voltage control device that is inserted between an AC power source and an AC load and controls a load voltage applied to the AC load, the AC voltage control device comprising:
  A one-capacitor horizontal half-bridge magnetic energy regenerative bidirectional current switch composed of a capacitor and a circuit connected in parallel to the capacitor and connected in reverse series with two reverse conducting semiconductor switches;
  A phase control device for controlling on / off of the reverse conducting semiconductor switch,
  The capacitance of the capacitor is set to a value such that the resonance frequency determined by the capacitance of the capacitor and the inductance of the AC load is higher than the power supply frequency of the AC power supply,
  Further, the phase control device controls so that when one of the two reverse-conducting semiconductor switches connected in reverse series is turned on, the other is turned off, and the phase of the current is forced By controlling on / off of the reverse conducting semiconductor switch so as to proceed, a voltage for compensating the reactance voltage of the AC load is generated in the capacitor, and the load voltage applied to the AC load is controlled. An AC voltage control device characterized by that. An AC voltage control device according to any one of claims 1 to 10 ,
Using a non-inductive load as the AC load,
An AC voltage control device for a non-inductive load that reduces the load voltage and generates a phase advance current. 12. The non-inductive load AC voltage control apparatus according to claim 11 , wherein the non-inductive load is a lamp load.   The AC voltage control apparatus according to claim 1, wherein the phase control apparatus performs pulse width modulation (PWM) to reduce harmonics included in the AC power supply. Using a three-phase alternating current as the AC power source, said one of the harmonics of the AC power supply, according to any one of claims 1 to 13, characterized in that automatically extinguished by delta connection the third harmonic AC voltage control device. As a self-turn-off elements forming each said reverse conducting semiconductor switch, a power MOSFET, IGBT, GTO, etc., exchange of any one of claims 1 to 14, characterized in that using the off Switching element Power supply pressure control device.

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