JP2009195058A - Ac power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an AC power supply device such as a single-phase uninterruptible AC power supply device of which the number of components and the power loss are required to be reduced. <P>SOLUTION: A half bridge type AC-DC conversion circuit is formed of first and second switches Q1, Q2, first and second capacitors 7, 8 and a first reactor 6. A power storage battery 12 is connected to the lower end of a serial circuit of the first and second capacitors 7, 8. The serial circuit of third and fourth switches Q3, Q4 for constituting the half bridge type inverter is connected in parallel to the serial circuit of the first and second capacitors 7, 8. First to fifth mode changeover switches 13 to 17 are provided which switch connection relationships among a mutual connection point P1 between the first and second capacitors 7, 8, a mutual connection point P2 between the first and second switches Q1, Q2, an AC power supply 1, a load 2, and the power storage batter 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an AC power supply apparatus such as a single-phase AC uninterruptible power supply apparatus that can supply an AC voltage having a desired frequency and a desired voltage value to a load based on the AC power supply voltage.

As shown in FIG. 1, a conventional typical single-phase AC uninterruptible power supply apparatus includes an input high-frequency capacitor C1, input reactors L1 and L2, and a DC-AC converter or converter CONV between an AC power supply AC and a load R. , Storage battery BT, DC link capacitor C2, AC-DC converter, that is, inverter INV, output reactors L3 and L4, output high frequency capacitor C3, and commercial transformer Tr. The converter CONV includes first, second, third, and fourth switches Q11, Q12, Q13, and Q14 and first, second, third, and fourth diodes D11, which are represented by IGBTs (insulated gate bipolar transistors). It is a full bridge type converter provided with D12, D13, D14. The inverter INV includes fifth, sixth, seventh and eighth switches Q15, Q16, Q17 and Q18 indicated by IGBT and fifth, sixth, seventh and eighth diodes D15, D16, D17 and D18. It is a full bridge type inverter provided with.

The single-phase AC uninterruptible power supply of FIG. 1 has the feature that even if the input voltage has distortion, it can output a voltage with a constant amplitude without distortion, and the waveform of the input current is a sine wave. The power factor can be improved and the power factor can be improved. However, since the single-phase AC uninterruptible power supply apparatus of FIG. 1 includes the converter CONV and the inverter INV, and includes eight switches Q11 to Q18, eight diodes D11 to D18, and a transformer Tr. It has the disadvantage of being large and expensive.

  In order to solve the drawbacks of the single-phase AC uninterruptible power supply of FIG. 1, the single-phase AC uninterruptible power supply of FIG. 2 that combines a half-bridge converter and a half-bridge inverter is known. The single-phase AC uninterruptible power supply device shown in FIG. 2 includes an AC power supply AC, a boosting reactor L11, first and second switches Qa and Qb including transistors constituting a half-bridge converter, and a half-bridge inverter. The third and fourth switches Qc, Qd comprising transistors constituting the first, second, third and fourth diodes Da, Db, Dc, Dd, and the first and second capacitors C11, C12 And a smoothing reactor L12, a storage battery BT, and a load R. The first capacitor C11 is charged via the first diode Da, and the second capacitor C12 is charged via the second diode Db. The accumulation of energy in the reactor L11 is controlled by the first and second switches Qa and Qb. By storing energy in the reactor L11, the first and second capacitors C11 and C12 are charged by a voltage obtained by adding the voltage of the AC power supply AC and the voltage of the reactor L11, and function as a DC power supply for the half-bridge inverter. To do.

The single-phase AC uninterruptible power supply device of FIG. 2 is configured based on a half-bridge type converter and a half-bridge type inverter, so that a transformer is not required compared to the single-phase AC uninterruptible power supply device of FIG. In addition, the number of switches, diodes, and reactors is halved, and the size and cost can be reduced. On the other hand, the voltages applied to the switches Qa to Qd and the diodes Da to Dd are first and first. 2 is twice the voltage of the capacitors C11 and C12, so that the loss due to switching increases. For example, when an AC voltage of 200 V (effective value) is supplied to the load R using an AC power source AC of 200 V (effective value), a minimum voltage of 282 V (peak value) is applied to each of the switches Q11 to Q18 in the method of FIG. 2, the voltage of 564V, which is twice that of the diodes D11 to D18, is applied to each of the switches Qa to Qd and each of the diodes Da to Dd, resulting in a significant increase in switching loss. Further, since all of the current required by the load R flows through the switches Qa to Qd, the conduction loss in the switches Qa to Qd becomes relatively large.

  As a modification of the half-bridge type converter and the half-bridge type inverter of FIG. 2, an AC power source as shown by a chain line instead of connecting one end (left end) of the load R to the interconnection point of the first and second capacitors C11 and C12. A method of connecting to one end of the AC is disclosed in Japanese Patent Laid-Open No. 7-337036 (Patent Document 1). In the method of Patent Document 1, a voltage obtained by adding the voltage of the inverter to the voltage of the AC power supply AC is applied to the load R. However, Patent Document 1 only discloses a circuit that does not have the storage battery BT of FIG. 2, and does not disclose an uninterruptible power supply that can cope with a relatively long power failure. Further, there is no disclosure of a method for dealing with the case where the frequency of the AC power supply of the AC power supply AC is abnormal.

A voltage adjusting circuit using an AC chopper circuit shown in FIG. 3 is known as a voltage adjusting circuit for supplying a stabilized AC voltage to a load. In this voltage adjustment circuit, an AC chopper circuit is connected between one end of the AC power supply AC and one end of the load R, and the other end of the AC power supply AC and the other end of the load R are both connected to the ground terminal. The AC chopper circuit includes a series circuit of first and second switches Q11 and Q12, and third and fourth switches Q13 and Q12 connected in parallel to the series circuit of the first and second switches Q11 and Q12. A series circuit of Q14, a capacitor Cs connected in parallel to the series circuit of the third and fourth switches Q13 and Q14, and a series circuit of fifth and sixth switches Q15 and Q16 are included. The interconnection point of the first and second switches Q11 and Q12 is connected to one end of the AC power supply AC via the input reactor Li. The interconnection point of the third and fourth switches Q13 and Q14 is connected to the other end of the AC power supply AC. An input filter capacitor Ci is connected in parallel with the AC power supply AC. The interconnection point of the fifth and sixth switches Q15 and Q16 is connected to one end of the load R via the output reactor Lo. An output filter capacitor Co is connected in parallel with the load R. The first, second, third, fourth, fifth, and sixth switches Q11, Q12, Q13, Q14, Q15, and Q16 are arranged in parallel in the reverse direction in the first, second, third, fourth, and fifth. The sixth diodes D11, D12, D13, D14, D15, and D16 are connected.

The voltage adjustment circuit using the AC chopper circuit shown in FIG. 3 has an advantage that an output voltage (load voltage) compensated for the amplitude fluctuation of the AC power supply voltage can be obtained with a relatively simple circuit. However, the potential of one end and the other end of the capacitor Cs with respect to the ground (ground) changes in accordance with a periodic change in the AC power supply voltage (for example, a change of 50 Hz or 60 Hz). For this reason, when the frequency of an alternating current power supply voltage fluctuates, it has the fault that the alternating voltage of a fixed frequency cannot be supplied to the load R. In addition, the number of switches and the number of diodes are increased by two as compared with the uninterruptible power supply of FIG.
JP-A-7-337036

The problem to be solved by the present invention is that a small and low-cost AC power supply device such as an uninterruptible power supply is required, and the object of the present invention is to supply AC power that can meet this requirement. Is to provide a device.

Next, the present invention will be described with reference numerals in the drawings showing an embodiment of the present invention. It should be noted that the claims and the reference numerals used here are for helping understanding of the present invention, and do not limit the present invention.
An AC power supply apparatus according to the present invention
First and second power supply terminals for supplying an AC power supply voltage;
A series circuit of first and second capacitors;
A series circuit of first and second switches connected in parallel to the series circuit of the first and second capacitors to form a converter;
A series circuit of third and fourth switches connected in parallel to the series circuit of the first and second capacitors to form an inverter;
First mode changeover switch means (13 or A and F1) connected between the first power supply terminal and the interconnection point of the first and second capacitors;
Second mode changeover switch means (14 or B and F1) connected between the second power supply terminal and the interconnection point of the first and second capacitors;
Third mode changeover switch means (16 or D and F2) connected between the first power supply terminal and the interconnection point of the first and second switches;
Fourth mode changeover switch means (17, or E and F2) connected between the second power supply terminal and the interconnection point of the first and second switches;
A load connected between an interconnection point of the third and fourth switches and the second power supply terminal;
When the frequency and voltage value of the AC power supply voltage between the first and second power supply terminals are normal, the first and fourth mode changeover switch means are turned on, and the second and third mode changeover switch means When the frequency of the AC power supply voltage is abnormal and the voltage value is normal, the first and fourth mode changeover switch means are turned off and the second and third mode changeover switch means A mode switching control circuit for controlling ON,
A converter control circuit for controlling the first and second switches so as to convert the AC power supply voltage into a DC voltage;
And an inverter control circuit for controlling the third and fourth switches so as to apply an AC voltage having a desired frequency and a desired voltage value to the load.
In the present application, even when the power supply to the load is short enough to be ignored (for example, ¼ cycle or less of the _AC power supply voltage V _AC ), it is regarded as uninterrupted.
In the present application, the converter means an AC-DC conversion circuit or a DC-DC conversion circuit, and the inverter means a DC-AC conversion circuit.

In addition, as shown in claim 2, the AC power supply device is
First and second power supply terminals for supplying an AC power supply voltage;
A series circuit of first and second capacitors;
A series circuit of first and second switches connected in parallel to the series circuit of the first and second capacitors to form a converter;
A series circuit of third and fourth switches connected in parallel to the series circuit of the first and second capacitors to form an inverter;
A storage battery having one end and the other end for supplying a DC voltage, the one end being connected to one end of a series circuit of the first and second capacitors;
First mode changeover switch means (13 or A and F1) connected between the first power supply terminal and the interconnection point of the first and second capacitors;
Second mode changeover switch means (14 or B and F1) connected between the second power supply terminal and the interconnection point of the first and second capacitors;
Third mode changeover switch means (15, or C and F2) connected between the other end of the storage battery and the interconnection point of the first and second switches;
Fourth mode changeover switch means (17, or E and F2) connected between the second power supply terminal and the interconnection point of the first and second switches;
A load connected between an interconnection point of the third and fourth switches and the second power supply terminal;
When the frequency and voltage value of the AC power supply voltage between the first and second power supply terminals are normal, the first and fourth mode changeover switch means are turned on, and the second and third mode changeover switch means And the first and fourth mode changeover switch means are turned off and the second and third mode changeover switch means are turned on when both the frequency and voltage value of the AC power supply voltage are abnormal. A mode switching control circuit to control;
The AC power supply voltage is converted to a DC voltage when the frequency and voltage value of the AC power supply voltage between the first and second power supply terminals are normal, and the frequency and voltage value of the AC power supply voltage are both abnormal. A converter control circuit for controlling the first and second switches so as to convert a DC voltage of the storage battery into a DC voltage required by a series circuit of the first and second capacitors;
An inverter control circuit that controls the third and fourth switches so as to apply an AC voltage having a desired frequency and a desired voltage value to the load may be used.
Moreover, as shown in claim 3, the AC power supply device is
First and second power supply terminals for supplying an AC power supply voltage;
A series circuit of first and second capacitors;
A series circuit of first and second switches connected in parallel to the series circuit of the first and second capacitors to form a converter;
A series circuit of third and fourth switches connected in parallel to the series circuit of the first and second capacitors to form an inverter;
A storage battery having one end and the other end for supplying a DC voltage, the one end being connected to one end of a series circuit of the first and second capacitors;
First mode changeover switch means (13 or A and F1) connected between the first power supply terminal and the interconnection point of the first and second capacitors;
Second mode changeover switch means (14 or B and F1) connected between the second power supply terminal and the interconnection point of the first and second capacitors;
Third mode changeover switch means (15 or C and F2) connected between the other end of the storage battery and the interconnection point of the first and second switches;
A fourth mode changeover switch means (16, or D and F2) connected between the first power supply terminal and the interconnection point of the first and second switches;
Fifth mode changeover switch means (17 or E and F2) connected between the second power supply terminal and the interconnection point of the first and second switches;
A load connected between an interconnection point of the third and fourth switches and the second power supply terminal;
When the frequency and voltage value of the AC power supply voltage between the first and second power supply terminals are normal, the first and fifth mode changeover switch means are controlled to be turned on, and the second, third and fourth modes are controlled. When the changeover switch means is turned off, and when the frequency of the AC power supply voltage is abnormal and the voltage value is normal, the first, third and fifth mode changeover switch means are turned off and the second and second modes A mode switching control circuit for turning on the mode switching switch means;
When the voltage value of the AC power supply voltage between the first and second power supply terminals is normal, the AC power supply voltage is converted into a DC voltage, and when one or both of the frequency and voltage value of the AC power supply voltage are abnormal, A converter control circuit for controlling the first and second switches so as to convert a DC voltage of the storage battery into a DC voltage required by a series circuit of the first and second capacitors;
An inverter control circuit that controls the third and fourth switches so as to apply an AC voltage having a desired frequency and a desired voltage value to the load may be used.
Further, as shown in claim 4, the first reactor (inductance) connected to the interconnection point of the first and second switches and the interconnection point of the third and fourth switches It is desirable to have a connected second reactor (inductance).
Moreover, as shown in Claim 5, it is desirable to further have a charging means for charging the storage battery.

The invention of each claim has the following effects.
(1) Although the circuit configuration is simplified as compared with the conventional single-phase AC uninterruptible power supply device shown in FIG. 1, the first to fourth mode changeover switches are reduced in size and cost. Since it is provided, supply of an AC voltage having a desired frequency to the load can be continued even if an abnormality occurs in the frequency of the AC power supply voltage.
(2) When the AC power supply voltage is normal, only the current for compensating for distortion of the input current and the current for maintaining the DC voltage constant flow through the first and second switches, and the effective current for the load. Does not flow. Therefore, power loss in the first and second switches is reduced.

  Next, embodiments of the present invention will be described with reference to the drawings.

The single-phase AC uninterruptible power supply as an AC power supply apparatus according to the first embodiment of the present invention shown in FIG. As in the conventional circuit of FIG. 2, it has an AC-DC conversion function (converter function) and a DC-AC conversion function (inverter function). However, the single-phase AC uninterruptible power supply according to the first embodiment has the following new points as compared with the conventional circuit of FIG.
1. A load 2 is connected between one end of the AC power source 1 and the output terminal 3 of the inverter.
2. The amplitude fluctuation of the AC power supply voltage is corrected by the inverter.
3. When the frequency or voltage value (amplitude or effective value) of the AC power supply voltage or both are abnormal, the first, second, third, fourth and fifth, preferably consisting of an electromagnetic contactor or a mechanical relay or a semiconductor switch The first, second, third, fourth, and fourth switches Q1, by the first, second, third, fourth, and fifth mode changeover switches 13, 14, 15, 16, and 17 as the mode changeover switch means. The power conversion mode is switched by Q2, Q3, and Q4, and an alternating voltage having a desired frequency or voltage value (amplitude or effective value) is supplied to the load 2.

Next, each part of the single-phase alternating current uninterruptible power supply device of FIG. 4 will be described in detail. This single-phase AC uninterruptible power supply device has an AC-DC-AC conversion circuit between an AC power supply 1 and a load 2. The conversion circuit includes a series circuit of first and second capacitors 7 and 8, and first and second switches Q1, 2 connected in parallel to the series circuit of the first and second capacitors 7 and 8. A series circuit of Q2, a series circuit of third and fourth switches Q3 and Q4 connected in parallel to the series circuit of the first and second capacitors 7 and 8, and the first and second reactors 6 , 9.

The AC power source 1 is a power source having a rated voltage (target voltage) of, for example, 100 V (effective value) and a rated frequency (target frequency) of 50 Hz, and is connected to the first and second power terminals 1a and 1b. In this embodiment, the second power supply terminal 1b is connected to the ground. Further, the positive direction of the _AC power supply voltage V _AC of the _AC power supply 1 is determined to be a direction from the first power supply terminal 1a to the second power supply terminal 1b. In addition, the AC power source 1 is configured such that one or both of the frequency and voltage value of the _AC power source voltage V _AC may fluctuate or a power failure may occur.

The series circuit of the first and second capacitors 7 and 8 is connected between the positive side DC conductor (line) 4 and the negative side DC conductor (line) 5. The interconnection point P1 of the first and second capacitors 7 and 8 is connected to the first power supply terminal 1a of the AC power supply 1 via the first mode changeover switch 13 and via the second mode changeover switch 14. The AC power supply 1 is connected to the second power supply terminal 1b. The first and second capacitors 7 and 8 have a DC voltage dividing function for the half-bridge type converter and the half-bridge type inverter.

The single-phase AC uninterruptible power supply has a storage battery 12 for backing up a power failure or abnormality of the AC power supply 1. One end (negative terminal) of the storage battery 12 is connected to the negative DC conductor (line) 5. The other end (positive terminal) of the storage battery 12 is connected to the interconnection point P2 of the first and second switches Q1, Q2 via the third mode changeover switch 15 and the first reactor 6. The other end (positive terminal) of the storage battery 12 is connected to the charging means 12a. The charging means 12 a charges the storage battery 12 by converting the _AC power supply voltage V _AC of the AC power supply 1 into a DC voltage. In addition, the charging means 12a can be used as a switch, and the storage battery 12 can be charged by selectively connecting the storage battery 12 to the positive DC conductor (line) 4 via the switch of the charging means 12a as shown by a dotted line 12b. The storage battery 12 is charged during a period that does not interfere with the inverter operation.

The series circuit of the first and second switches Q1, Q2 is connected in parallel to the series circuit of the first and second capacitors 7, 8, and is connected to the positive side DC conductor (line) 4 and the negative side DC conductor (line). ) 5 is connected. The first and second switches Q1, Q2 constitute a half bridge converter having an active filter function. The interconnection point P2 between the first and second switches Q1, Q2 is connected to the first power supply terminal 1a through the first reactor 6 and the fourth mode changeover switch 16, and the first reactor 6 and the second switch 5 is connected to the second power supply terminal 1b via a mode changeover switch 17. The first reactor 6 functions as a boosting inductance and filter for the boost converter.

The series circuit of the third and fourth switches Q3, Q4 is connected in parallel to the series circuit of the first and second capacitors 7, 8, and is connected to the positive side DC conductor (line) 4 and the negative side DC conductor (line). ) 5 is connected. The third and fourth switches Q3 and Q4 constitute a half bridge type inverter. The interconnection point P3 of the third and fourth switches Q3 and Q4 is connected to the AC output terminal 3 via the second reactor 9 for the output filter.

Each of the first, second, third and fourth switches Q1, Q2, Q3 and Q4 comprises an insulated gate field effect transistor (FET), and the first, second, third and fourth FET switches S1. , S2, S3, S4 and first, second, third and fourth parasitic diodes D1, D2, D3, D4. The first, second, third and fourth FET switches S1, S2, S3 and S4 each have a drain, a source and a gate (control terminal). The first, second, third and fourth parasitic diodes D1, D2, D3 and D4 are in reverse parallel to the first, second, third and fourth FET switches S1, S2, S3 and S4. It is connected. The first and second parasitic diodes D1 and D2 function as rectifier diodes during converter operation. The third and fourth parasitic diodes D3 and D4 contribute to flow the regenerative current or circulating current of the inverter. The first, second, third and fourth parasitic diodes D1, D2, D3 and D4 can be replaced with individual diodes.

An input stage filter capacitor 10 is connected between the interconnection point P1 of the first and second capacitors 7 and 8 and the input side conductor 28 of the first AC reactor 6. An output stage filter capacitor 11 is connected via a second AC reactor 9 between the interconnection point P3 of the third and fourth switches Q3 and Q4 and the second power supply terminal 1b.

One end of the load 2 is connected to the output terminal 3, and the other end is connected to the second power supply terminal 1b. Details of the voltage V _AB applied to the load 2 will be described later.

First and second current detectors 18 and 19 are provided to control the first to fourth switches Q1 to Q4 and the first to fifth mode changeover switches 13 to 17, and a control circuit 32 is further provided. Is provided. The first current detector 18 is electromagnetically coupled to the power supply line between the second power supply terminal 1b and the fifth mode changeover switch 17 in order to obtain an AC input current detection signal, and the second current detector 19 is In order to obtain an output current detection signal, it is electromagnetically coupled to the power supply line between the interconnection point P3 of the third and fourth switches Q3, Q4 and the output terminal 3. The first and second current detectors 18 and 19 are connected to the control circuit 32 by lines 18a and 29. Also, a line 20 for detecting the potential of the first power supply terminal 1a, a line 21 for detecting the potential _VA of the second power supply terminal 1b, and a line 22 for detecting the potential of the positive side DC conductor 4 are shown. The control circuit 32 includes a line 23 for detecting the potential of the negative side DC conductor 5, a line 30 for detecting the potential V _B of the output terminal 3, and a line 31 for detecting the potential of the lower end of the load 2. Each is connected. The gates of the first, second, third and fourth FET switches S1, S2, S3 and S4 and the control circuit 32 are connected by lines 24, 25, 26 and 27, respectively. The gate control signals of the first, second, third, and fourth FET switches S1, S2, S3, and S4 are applied between the gates and the sources. Therefore, in practice, not only the gate but also the source is connected to the control circuit 32 in order to apply the gate control signal, but this connection is omitted for the sake of simplicity of illustration. The control terminals of the first, second, third, fourth and fifth mode change-over switches 13, 14, 15, 16, 17 are connected to the control circuit 32 by lines 13a, 14a, 15a, 16a, 17a. .

The control circuit 32 has the following functions.
1. AC power supply voltage V _AC is first and second power supply terminal 1a, when being normally supplied to 1b, the first and second to convert an AC power source voltage V _AC to a DC voltage by a half-bridge converter operation A control signal for controlling the switches Q1 and Q2 is formed and supplied to the gates of the first and second switches Q1 and Q2. Also, a control signal for converting the DC voltage into an AC voltage synchronized with the _AC power supply voltage V _AC is generated by the half-bridge inverter operation, and this is supplied to the gates of the third and fourth switches Q3 and Q4. Further, a signal for controlling the first and fifth mode change-over switches 13 and 17 to be turned on and a signal for controlling the second, third and fourth mode change-over switches 14, 15, and 16 to be turned off are formed. Further, the first and second switches Q1, Q2 are controlled so that the AC input current flowing through the first and second power supply terminals 1a, 1b becomes a sine wave. That is, the first and second switches Q1 and Q2 are controlled so that the active filter operation occurs. Further, the third and fourth switches Q3 and Q4 are controlled so that the load voltage V _AB corresponding to the voltage obtained by superimposing the output voltage of the half-bridge inverter on the _AC power supply voltage V _AC becomes a desired value. Hereinafter, this control mode is referred to as a first control mode or a normal control mode. FIG. 4 shows a single-phase AC uninterruptible power supply in the first control mode.
2. When the frequency of the AC power supply voltage V _AC between the first and second power supply terminals 1a and 1b is abnormal and the voltage value (amplitude and effective value) is normal, the second and fourth mode changeover switches 14 and 16 are turned on. And a signal for controlling the first, third, and fifth mode change-over switches 13, 15, and 17 to be turned off. Further, a control signal for controlling the first and second switches Q1, Q2 is formed so as to convert the _AC power supply voltage V _AC into a DC voltage by the half-bridge type converter operation, and this is converted into the first and second signals. Supply to the gates of the switches Q1 and Q2. Also, a control signal for converting the DC voltage into an AC voltage asynchronous with respect to the AC power supply voltage V _AC is generated by the half-bridge inverter operation, and this is supplied to the gates of the third and fourth switches Q3 and Q4. To do. In this control mode, the inverter output voltage is set to the load voltage V _AB without superimposing the inverter output voltage on the _AC power supply voltage V _AC . Hereinafter, this control mode is referred to as a second control mode or a frequency abnormality control mode. FIG. 5 shows a single-phase AC uninterruptible power supply device in the second control mode.
3. When both the frequency and voltage value (amplitude and effective value) of the AC power supply voltage V _AC between the first and second power supply terminals 1a and 1b are abnormal or a power failure occurs, the second and third mode changeover switches 14, 15 and the first, fourth and fifth mode change-over switches 13, 16, and 17 are turned off. In addition, a control signal for controlling the first and second switches Q1, Q2 is formed so as to operate the boost converter, and this is supplied to the gates of the first and second switches Q1, Q2. Further, a control signal for converting the DC voltage into an AC voltage having a frequency and a voltage value (amplitude and effective value) required by the load 2 is formed by the half-bridge type inverter operation, and this is converted into the third and fourth switches Q3. , Q4 are supplied to the gates. Hereinafter, this control mode is referred to as a third control mode or a frequency and voltage value abnormality control mode. FIG. 6 shows a single-phase AC uninterruptible power supply in the third control mode.

FIG. 7 shows details of the control circuit 32 for obtaining the first, second and third control modes. This control circuit 32 roughly includes a converter control circuit 61, an inverter control circuit 62, a power supply voltage detection circuit 63, and a mode switching control circuit 64.

The converter control circuit 61 converts a signal for controlling the first and second switches Q1 and Q2 so as to convert the _AC power supply voltage V _AC into a DC voltage, or converts the DC voltage of the storage battery 12 into a boosted DC voltage. In order to form a signal for controlling the first and second switches Q1 and Q2 and supply it to the gates of the first and second switches Q1 and Q2, and to detect a DC voltage DC voltage detection circuit 41 connected to lines 22 and 23, DC voltage reference value generator 33, DC voltage detection signal of DC voltage detection circuit 41 and DC voltage reference value of DC voltage reference value generator 33. It has a subtractor 34a that forms a signal indicating the difference, and a proportional integration circuit (PI) 34b. The proportional integration circuit 34b outputs a DC voltage control signal for controlling the DC voltage between the lines 22 and 23 to be constant. The subtractor 34a and the proportional integration circuit 34b can be integrated into an error amplification circuit. The amplitude adjustment circuit (G) 36 adjusts the amplitude of the power supply voltage detection signal obtained from the power supply voltage detection circuit 63 and sends it to the multiplier 35. The power supply voltage detection circuit 63 detects a signal indicating the _AC power supply voltage VAC based on the signals on the lines 20 and 21. The multiplier 35 multiplies the sine wave AC signal obtained from the amplitude adjustment circuit 36 by the DC voltage control signal obtained from the proportional integration circuit 34b, and outputs an amplitude-adjusted sine wave AC signal. A subtractor 37a connected to the multiplier 35 forms a signal indicating the difference between the sinusoidal AC signal obtained from the multiplier 35 and the AC input current detection signal on the line 18a. The proportional integration circuit (PI) 37b proportionally integrates the output of the subtractor 37a and outputs a signal indicating the difference between the sine wave AC signal and the AC input current detection signal. The subtractor 37a and the proportional integration circuit 37b can be integrated into an error amplification circuit. One input terminal of the comparator 38 is connected to the proportional integration circuit 37 b, and the other input terminal is connected to the triangular wave generation circuit 39. Therefore, the comparator 38 has a triangular wave voltage (or a repetition frequency) sufficiently higher than the signal V1 obtained from the proportional integration circuit 37b and the AC power supply voltage V _AC obtained from the triangular wave generation circuit 39 shown in FIG. 9 is compared with the sawtooth voltage V2 and the PWM signal shown in FIG. 9B is output. The signal V1 input to the comparator 38 includes DC voltage information, AC input current amplitude, and waveform information. As a result, a signal for controlling the DC voltage V _PN between the positive side DC conductor 4 and the negative side DC conductor 5 to be constant and approximating the waveform of the AC input current to a sine wave and bringing the power factor close to 1 is obtained. Output from the comparator 38. In the third control mode shown in FIG. 6, the output of the power supply voltage detection circuit 63 is zero, and the input current detection of the line 18 is also zero. Therefore, the converter control circuit 61 of FIG. 7 is provided with means for directly inputting the output of the proportional integration circuit 34b to one input terminal of the comparator 38 in the third control mode. Although this means is not specifically shown in FIG. 7, for example, the output of the proportional integration circuit 34b is not adjusted in the third control mode, and the multiplier 35, the subtractor 37a, and the proportional integration circuit (PI) 37b are not adjusted. Or is input to one input terminal of the comparator 38, or is turned on only in the third control mode between the proportional integration circuit 34b and one input terminal of the comparator 38. In the third control mode, instead of the output of the proportional integration circuit (PI) 37b, the output of the proportional integration circuit 34b is input to one input terminal of the comparator 38 via the switch. The
The control signal forming circuit 40 forms signals for controlling the first and second FET switches S1 and S2 of FIG. 4 based on the output of the comparator 38, and sends them to the lines 24 and 25. The signal of FIG. 9B is sent to the line 24, and the phase inversion signal of FIG. 9B is sent to the line 25.

The inverter control circuit 62 in FIG. 7 has a reference sine wave generator 42 that generates a reference sine wave having the same frequency as the sine wave voltage required by the load 2. The phase synchronization control circuit 43 connected to the reference sine wave generator 42 and the power supply voltage detection circuit 63 compares the phase of the AC power supply voltage V _{AC with} the phase of the reference sine wave generator 42. A reference sine wave whose phase is shifted so that the phase of the reference sine wave of the reference sine wave generator 42 gradually approaches the phase of the _AC power supply voltage V _AC is sent to the multiplier 44 in the next stage. If the AC power supply voltage V _AC is not generated due to a power failure, the reference sine wave of the reference sine wave generator 42 becomes the output of the phase synchronization control circuit 43. The output stage multiplier 44 of the phase synchronization control circuit 43 multiplies the reference sine wave output from the phase synchronization control circuit 43 by a signal indicating the amplitude of the reference AC voltage generated from the reference AC voltage amplitude signal generator 45. Thus, a target AC output voltage signal having a desired amplitude, a desired phase, and a desired frequency is formed. The AC output voltage detection circuit 46 detects the AC output voltage, that is, the load voltage V _AB obtained between the lines 30 and 31, and sends a signal indicating the load voltage V _AB to the subtractor 47a as an AC output voltage detection signal. The subtractor 47 a outputs a signal indicating the difference between the target AC output voltage signal obtained from the multiplier 44 and the AC output voltage detection signal obtained from the AC output voltage detection circuit 46. The proportional integration circuit 47b proportionally integrates the output signal of the subtractor 47a and outputs an output voltage command signal. Note that the error amplifying circuit may be configured by integrating the subtractor 47a and the proportional integration circuit 47b. The subtractor 48a at the output stage of the proportional integration circuit 47b subtracts the output current detection signal of the line 29 from the output of the proportional integration circuit 47b. The proportional integration circuit 48b proportionally integrates the output of the subtractor 48a and outputs an output voltage command signal whose amplitude is corrected by the output current. The subtractor 48a and the proportional integration circuit 48b can be integrated to constitute an error amplifier. Further, when the correction by the current is unnecessary, the subtracter 48a and the proportional integration circuit 48b can be omitted. The comparator 49 at the output stage of the proportional integration circuit 48b compares the output voltage command signal obtained from the proportional integration circuit 48b with the triangular wave voltage (or sawtooth voltage) obtained from the triangular wave generator 50 to form a PWM signal. To do. The triangular wave generator 50 generates a triangular wave (or sawtooth voltage) at a repetition frequency sufficiently higher than the AC power supply voltage V _AC , and can also be used as the triangular wave generation circuit 39 in the converter control circuit 61. The control signal formation circuit 51 at the output stage of the comparator 49 forms a signal for on / off control of the third and fourth FET switches S3 and S4 based on the output of the comparator 49. That is, the control signal forming circuit 51 forms a control signal for causing the third and fourth FET switches S3 and S4 to operate as a half bridge inverter. A signal corresponding to the PWM control signal obtained from the comparator 49 and the phase inversion signal are sent to the lines 26 and 27 derived from the control signal forming circuit 51.

  The mode switching control circuit 64 is connected to the output line 63a of the power supply voltage detection circuit 63. Based on the power supply voltage detection signal obtained from the power supply voltage detection circuit 63, the first, second, third, fourth, and The first, second, third, fourth and fifth mode switching control signals for controlling the fifth mode switching switches 13, 14, 15, 16, 17 are formed to generate lines 13a, 14a, 15a, 16a and 17a.

  FIG. 8 shows details of the mode switching control circuit 64 of FIG. The mode switching control circuit 64 is roughly divided into a frequency determination means 71, a power supply voltage value determination means 72, and a logic circuit 73.

The frequency determination unit 71 includes a frequency detection unit 75 connected to the output line 63 a of the power supply voltage detection circuit 63, a reference frequency generation unit 76, and a comparison unit 77. The comparison unit 77 compares the signal indicating the frequency of the _AC power supply voltage V _AC obtained from the frequency detection unit 75 with the signal indicating the reference frequency (frequency required by the load 2) obtained from the reference frequency generation unit 76, frequency when the frequency of the AC power source voltage V _AC is determined whether the deviation predetermined range from the reference frequency (e.g., + 1-1%), the frequency of the AC power supply voltage V _AC is deviated from a predetermined range from the reference frequency When a first voltage level signal indicating abnormality (for example, a low level or logic 0 signal) is output and the frequency of the _AC power supply voltage V _AC is not deviated from the reference frequency within a predetermined range (normal), the second is output. Voltage level signal (for example, a high level or logic 1 signal) is output. The frequency determination means 71 is not limited to the circuit shown in FIG. 8, and can be replaced with any circuit that can determine whether the frequency is normal or abnormal.

The power supply voltage value determination means 72 is connected to the output line 63 a of the power supply voltage detection circuit 63 and comprises effective value detection means 78, reference effective value generation means 79, and comparison means 80. The comparing means 80 is a signal indicating the effective value of the _AC power supply voltage V _AC obtained from the effective value detecting means 78 and a signal indicating the reference effective value (effective value required by the load 2) obtained from the reference effective value generating means 79. comparing the door, from the AC power source voltage a predetermined range (e.g., + 20-20%) effective value from the reference effective value of V _AC determines whether deviation, the AC power source voltage V _AC effective value reference effective value Outputs a first voltage level signal (for example, a low level or logic 0 signal) indicating an abnormal RMS value (abnormal power supply voltage value) when it deviates from a predetermined range, and the effective value of the AC power supply voltage V _AC is a reference. When the value does not deviate from the effective range, a second voltage level signal (for example, a high level signal, ie, a logical one signal) is output. Note that the effective value V of the _AC power supply voltage V _AC and the maximum amplitude (peak value) Vm have a relationship of V = Vm / 2 ^1/2 and the effective value V is proportional to the maximum amplitude (peak value) Vm. AC power supply can be modified to determine the normal and abnormal maximum amplitude of the AC power supply voltage V _AC instead of determining the normal and abnormal voltage V _AC rms. Therefore, the power supply voltage value in the present application means all values indicating the magnitude of the power supply voltage such as the effective value or the maximum amplitude or the average value of the _AC power supply voltage V _AC . Further, the power supply voltage value determination means 72 is not limited to the circuit shown in FIG. 8, and can be replaced with any circuit that can determine whether the power supply voltage value is normal or abnormal.

  The logic circuit 73 controls the first, second, third, fourth, and fifth mode change-over switches 13, 14, 15, 16, and 17 based on the outputs of the frequency determination means 71 and the power supply voltage value determination means 72. First, second, third, fourth and fifth mode switching control signals for selective control are formed and sent to lines 13a, 14a, 15a, 16a and 17a. 1 AND circuit (logical product circuit) 81, first NOT circuit (inversion circuit) 82, second NOT circuit (inversion circuit) 84, third NOT circuit (inversion circuit) 86, and second AND circuit ( AND circuit) 87. One input terminal of the first AND circuit 81 is connected to the comparison unit 77 of the frequency determination unit 71, and the other input terminal is connected to the comparison unit 80 of the power supply voltage value determination unit 72. The lines 13 a and 17 a are connected to the output terminal of the first AND circuit 81, and the line 14 a is connected via the first NOT circuit 82. The line 15 a is connected to the comparison unit 80 of the power supply voltage value determination unit 72 through the second NOT circuit 84. One input terminal of the second AND circuit 87 is connected to the comparison means 77 of the frequency determination means 71 via the third NOT circuit 86, and the other input terminal is connected to the comparison means 80 of the power supply voltage value determination means 72. Has been. The line 16 a is connected to the output terminal of the second AND circuit 87.

Next, the operation of the single-phase AC uninterruptible power supply device of FIG. 4 will be described.
First, the AC power source voltage V _AC frequency and voltage value of the AC power supply 1 when both (amplitude or effective value) is normal, i.e., the first control mode or the single-phase AC uninterruptible power supply in the normal control mode The operation will be described. When both the frequency and voltage value (amplitude or effective value) of the _AC power supply voltage V _AC are normal, a high level signal indicating normality is output from the frequency determination means 71 and the power supply voltage value determination means 72 of the mode switching control circuit 64. The As a result, a high level signal is output from the first AND circuit 81, and the first and fifth mode changeover switches 13 and 17 are turned on as shown in FIG. At this time, since the low level signal is output from the first NOT circuit 82 to the line 14a, the second mode changeover switch 14 is controlled to be in the OFF state. Further, since the low level signal is output from the second NOT circuit 84 to the line 15a, the third mode changeover switch 15 is controlled to be in the OFF state. Further, since the low level signal is output from the third NOT circuit 86, the low level signal is also output from the second AND circuit 87 to the line 16a, and the fourth mode switch 16 is controlled to be in the OFF state. .

When the first FET switch S1 is turned off and the second FET switch S2 is turned on in the normal control mode period shown in FIG. A first closed circuit including the second capacitor 8, the AC power source 1, the first mode change switch 13, the fifth mode change switch 17, the first reactor 6, and the second FET switch S2 is formed. The sum of the voltage of the second capacitor 8 and the AC power supply voltage V _AC is added to the first reactor 6, and energy is accumulated in the first reactor 6. Next, when the first FET switch S1 is ON-controlled and the second FET switch S2 is OFF-controlled during the period in which the positive voltage is generated from the AC power supply 1, the AC power supply 1 and the fifth mode The first capacitor 7 is a second closed circuit composed of a changeover switch 17, a first reactor 6, a first diode D1 or a first FET switch S1, a first capacitor 7, and a first mode changeover switch 13. Is charged to a value higher than the AC power supply voltage V _AC .

Next, when the first FET switch S1 is turned on and the second FET switch S2 is turned off during the period in which the negative voltage is generated from the AC power supply 1, the AC power supply 1 and the first mode switching are performed. A third closed circuit including the switch 13, the first capacitor 7, the first FET switch S1, the first reactor 6, and the fifth mode change switch 17 is formed, and the AC power supply voltage V _AC and the first A voltage summed with the voltage of the capacitor 7 is applied to the first reactor 6, and energy is accumulated in the first reactor 6. Next, when the second FET switch S2 is turned on and the first FET switch S1 is turned off during a period in which a negative voltage is generated from the AC power supply 1, the AC power supply 1 and the first mode switching are performed. A fourth closed circuit composed of the switch 13, the second capacitor 8, the second diode D2 or the second FET switch S2, the first reactor 6, and the fifth mode change switch 17 is formed. The second capacitor 8 is charged to a value higher than the AC power supply voltage V _AC by both the stored energy of the reactor 6 and the AC power supply 1.
If the AC power supply voltage V _AC is, for example, 100 V (effective value), the DC voltage V _PN between the positive DC conductor 4 and the negative DC conductor 5 is, for example, the peak value of the _AC power supply voltage V _AC ( 141V), which is equivalent to twice 282V.
Since the first and second FET switches S1 and S2 are ON / OFF controlled by the converter control circuit 61 of FIG. 7, the DC voltage V _PN becomes a constant value, and the waveform of the AC input current approximates a sine wave. . As a result, the DC voltage V _PN as the DC power supply voltage of the inverter is stabilized and power factor improvement is achieved. The first and second switches Q1 and Q2 only carry a current for compensating for distortion of the input current (current for making a sine wave) and a current for maintaining the DC voltage V _PN at a constant value. And no current flows for the load 2. Therefore, the power loss in the first and second switches Q1 and Q2 is smaller than the power loss in the first and second switches Qa and Qb and the first and second diodes Da and Db of the conventional circuit of FIG.

In the normal control mode period shown in FIG. 4, the third and fourth switches Q3 and Q4 are on / off controlled by the output of the inverter control circuit 62 of FIG. The on / off operation of the third and fourth switches Q3 and Q4 at this time is a half-bridge inverter operation. In the present embodiment, the load 2 is applied with the output voltage of the inverter superimposed (added or subtracted) on the _AC power supply voltage VAC. More specifically, during the ON period of the third FET switch S3, the first capacitor 7, the third FET switch S3 (or the third diode D3), the second reactor 9, the load 2, the fifth A closed circuit of the mode changeover switch 17, the AC power source 1 and the first mode changeover switch 13 is formed, and the second capacitor 8 and the first mode changeover switch are in the ON period of the fourth FET switch S4. 13, an AC power supply 1, a fifth mode changeover switch 17, a load 2, a second reactor 9, and a fourth FET switch S <b> 4 (or a fourth diode D <b> 4) are formed. To load 2 is connected between a second power supply terminal 1b and an output terminal 3 of the potential V _B at the potential V _A, the voltage V _AB of the load 2 and the output terminal 3 and the second power supply terminal 1b It becomes the voltage between. Here, if the voltage (inverter output voltage) between the interconnection point P1 of the first and second capacitors 7 and 8 and the output terminal 3 is V _BC , the load voltage V _AB and the AC power supply voltage V _AC The relationship with the inverter output voltage V _BC can be expressed by the following equation.
V _AB = V _AC -V _BC
If the maximum amplitude of the _AC power supply voltage V _AC consisting of a sine wave is lower than the rated voltage Vn by a voltage ΔV as shown in FIG. 10A, as shown in FIG. 10B, FIG. An inverter output voltage V _BC composed of a sine wave having a maximum amplitude of ΔV and having a reverse phase with respect to the AC power supply voltage V _AC is formed, and this is superimposed on the _AC power supply voltage V _AC and the maximum amplitude of the load voltage V _AB Becomes the rated voltage Vn as shown in FIG.

Conversely, when the maximum amplitude of the _AC power supply voltage V _AC is higher than the rated voltage Vn by ΔV as shown in FIG. 11 (A), the AC power supply voltage shown in FIG. 11 (A) is shown in FIG. 11 (B). An inverter output voltage V _BC that is in phase with V _AC and has a maximum amplitude of ΔV is formed, which is superimposed on the _AC power supply voltage V _AC, and the maximum amplitude of the load voltage V _AB is as shown in FIG. Becomes the rated voltage Vn. That is, when the AC power supply voltage V _AC is lower than the rated voltage Vn, the inverter output voltage −V _BC of the opposite phase is subtracted from the AC power supply voltage V _AC , and V _AB = V _AC − (− V _BC ) = V _AC + V _{According to the BC} equation, a desired load voltage V _AB higher than the AC power supply voltage V _AC is obtained. Further, when the AC power supply voltage V _AC is higher than the rated voltage Vn, the inverter output voltage V _BC-phase from the AC power source voltage V _AC is subtraction, according to the formula V _AB = V _AC -V _BC, AC power supply voltage V _AC A lower desired load voltage V _AB is obtained. Thereby, the load voltage V _AB can be maintained at a desired constant value (for example, 100 V) regardless of the fluctuation of the _AC power supply voltage V _AC . When the AC power supply voltage V _AC is the same as the desired load voltage V _AB , the third and fourth switches Q3 and Q4 are controlled so that the inverter output voltage V _BC becomes zero. When the AC power supply voltage V _AC has a waveform distortion, even if the AC power supply voltage V _AC is the same as the desired load voltage V _{AB at the} effective value or the maximum amplitude (peak value), a sine wave The third and fourth switches Q3 and Q4 are controlled so that the load voltage V _AB is obtained.

In the second control mode, that is, the frequency abnormality control mode, a low level signal indicating a frequency abnormality is output from the frequency determination means 71, and a high level signal indicating a power supply voltage value normal is output from the power supply voltage value determination means 72. As a result, a low level signal is output from the first AND circuit 81 and a high level signal is output from the first NOT circuit 82. Further, a high level signal is output from the third NOT circuit 86, and a high level signal is also output from the second AND circuit 87. As a result, a high level signal is supplied from the lines 14a and 16a to the second and fourth mode changeover switches 14 and 16, and the second and fourth mode changeover switches 14 and 16 are turned on as shown in FIG. Become. Since the lines 13a, 15a, and 17a are at a low level, the first, third, and fifth mode change-over switches 13, 15, and 17 are turned off as shown in FIG. In the second control mode, that is, the frequency abnormality control mode shown in FIG. 5, the load is generated by an AC-DC-AC (AC-DC-AC) conversion operation without an operation of superimposing the inverter output voltage _VBC on the _AC power supply voltage V _AC AC voltage is supplied to 2. That is, the AC power supply voltage V _AC is converted into a DC voltage by the half-bridge type converter operation based on the first and second switches Q1 and Q2, and the half-bridge type inverter operation based on the third and fourth switches Q3 and Q4. The DC voltage is converted into an AC voltage, and the output voltage of the half bridge inverter is applied to the load 2.

The AC-DC-AC (AC-DC-AC) conversion operation in the second control mode, that is, the frequency abnormality control mode shown in FIG. When the first FET switch S1 is on-controlled and the second FET switch S2 is off-controlled while the positive voltage is generated from the AC power source 1, the AC power source 1 and the second mode switch 14 A closed circuit comprising the first capacitor 7, the first FET switch S1, the first reactor 6, and the fourth mode change switch 16 is formed, and the voltage of the first capacitor 7 and the AC power supply voltage V _AC are The sum is added to the first reactor 6, and energy is accumulated in the first reactor 6. Next, when the first FET switch S1 is turned off and the second FET switch S2 is turned on during the period in which the positive voltage is generated from the AC power supply 1, the first reactor 6 and the fourth The second capacitor 8 is an AC power source in a closed circuit comprising the mode change switch 16, the AC power supply 1, the second mode change switch 14, the second capacitor 8 and the second diode D 2 or the second FET switch S 2. Charged to a value higher than voltage V _AC .
Next, when the second FET switch S2 is on-controlled and the first FET switch S1 is off-controlled while the negative voltage is generated from the AC power supply 1, the second capacitor 8 and the second capacitor 8 A closed circuit composed of the mode change switch 14, the AC power supply 1, the fourth mode change switch 16, the first reactor 6, and the second FET switch S 2 is formed, and the AC power supply voltage V _AC and the second capacitor 8 are A voltage summed with the voltage is applied to the first reactor 6, and energy is accumulated in the first reactor 6.
Next, when the second FET switch S2 is turned off and the first FET switch S1 is turned on during the period in which the negative voltage is generated from the AC power supply 1, the AC power supply 1 and the fourth mode switching are performed. In the closed circuit comprising the switch 16, the first reactor 6, the first FET switch S1 or the first diode D1, the first capacitor 7, and the second mode switch 14, the first capacitor 7 is the AC power supply voltage. Charged to a value higher than V _AC .

The half-bridge type inverter in the second control mode, that is, the frequency abnormality control mode shown in FIG. 5 is formed as follows. During the period when the third FET switch S3 is ON, the load 2 is a closed circuit comprising the first capacitor 7, the third FET switch S3, the second reactor 9, the load 2, and the second mode changeover switch 14. A positive direction voltage is applied to. During the period when the fourth FET switch S4 is on, the load 2 is a closed circuit composed of the second capacitor 8, the second mode changeover switch 14, the load 2, the second reactor 9, and the fourth FET switch S4. A negative direction voltage is applied to.

In the third control mode shown in FIG. 6, that is, in the frequency and voltage value abnormality control mode, a low level signal indicating a frequency abnormality is output from the frequency determination means 71, and the power supply voltage value determination means 72 also indicates a power supply voltage value abnormality. A low level signal is output. As a result, the lines 14a and 15a derived from the logic circuit 73 are at a high level, the lines 13a, 16a and 17a are at a low level, and the second and third mode changeover switches 14 and 15 are turned on as shown in FIG. On, the first, fourth, and fifth mode selector switches 13, 16, and 17 are turned off. As a result, the AC power supply 1 is disconnected from the first to fourth switches Q1 to Q4 and the load 2. In FIG. 6, a closed circuit including a storage battery 12, a third mode changeover switch 15, a first reactor 6, a first diode D 1, and first and second capacitors 7 and 8 is formed. A voltage is applied to the first and second capacitors 7, 8. Further, when the DC voltage V _PN of the series circuit of the first and second capacitors 7 and 8 is lower than a desired value, a known boost converter operation is caused by turning on and off the second FET switch S2, and the first and second The DC voltage V _PN of the series circuit of the capacitors 7 and 8 is controlled to a desired value.
When the third FET switch S3 is turned on to operate as a half-bridge inverter, the first capacitor 7, the third FET switch S3, the second reactor 9, the load 2, and the second mode changeover switch 14 are operated. When a forward voltage is applied to the load 2 and the fourth FET switch S4 is turned on, the second capacitor 8, the second mode change switch 14, the load 2 and the second A closed circuit comprising two reactors 9 and a fourth FET switch S4 is formed, and a negative voltage is applied to the load 2. The half-bridge inverter composed of the third and fourth switches Q3 and Q4 outputs an AC voltage having a voltage value (amplitude and effective value) and frequency required by the load 2 regardless of the abnormality of the AC power source 1. Thereby, a desired alternating voltage can be supplied to the load 2 without a power failure.

This embodiment has the following effects.
(1) Although the circuit configuration of the single-phase AC uninterruptible power supply device of FIG. 4 is simplified compared to the conventional single-phase AC uninterruptible power supply device of FIG. 1, the circuit configuration is reduced and the cost is reduced. Since the first to fifth mode changeover switches 13 to 17 are provided, an AC voltage having a desired frequency can be supplied to the load 2 even if the frequency abnormality of the _AC power supply voltage V _AC occurs.
(2) When the AC power supply voltage V _AC is normal, only the current for compensating the distortion of the input current and the current for maintaining the DC voltage constant flow through the first and second switches Q1 and Q2. For this reason, no effective current flows. Therefore, the power loss in the first and second switches Q1, Q2 is reduced.
(3) The first control mode (normal control mode) shown in FIG. 4, the second control mode (frequency abnormality control mode) shown in FIG. The third control mode (frequency and voltage value abnormality control mode) can be selectively set, and power supply suitable for all states of the AC power supply 1 can be achieved.

  FIG. 12 shows a single-phase AC uninterruptible power supply device according to the second embodiment. The single-phase AC uninterruptible power supply device of FIG. 12 is provided with first and second switchers 91 and 92 instead of the first to fifth mode change-over switches 13 to 17 of FIG. The same configuration. Therefore, in FIG. 12, the same reference numerals as those in FIG.

The first switch 91 has first and second contacts (fixed contacts) A and B and a first common contact (movable contact) F1, and is connected to lines 13a and 14a derived from the control circuit 32. Operates in response to control signals. That is, when the line 13a is at a high level, the first contact A and the first common contact F1 are electrically connected, and when the line 14a is at a high level, the second contact B and the first common contact F1. Are electrically connected. The first contact A is connected to the first power supply terminal 1a, the second contact b is connected to the second power supply terminal 1b, and the first common contact F1 is connected to the first and second capacitors 7 and 8. It is connected to the interconnection point P1. The combination of the first contact A and the first common contact F1 has a function equivalent to that of the first mode switch 13 in FIG. Therefore, the combination of the first contact A and the first common contact F1 can also be called the first mode changeover switch means. The combination of the second contact B and the first common contact F1 has a function equivalent to that of the second mode changeover switch 14 of FIG. Therefore, the combination of the second contact B and the first common contact F1 can also be referred to as second mode changeover switch means.

The second switch 92 has third, fourth and fifth contacts (fixed contacts) C, D, E and a second common contact (movable contact) F2, and is derived from the control circuit 32. Operates in response to control signals on lines 15a, 16a, 17a. That is, when the line 15a is at a high level, the third contact C and the second common contact F2 are electrically connected, and when the line 16a is at a high level, the fourth contact D and the second common contact F2 are connected. Are electrically connected, and the fifth contact E and the second common contact F2 are electrically connected when the line 17a is at a high level. The third contact C is connected to the positive terminal of the storage battery 12, the fourth contact D is connected to the first power supply terminal 1a, the fifth contact E is connected to the second power supply terminal 1b, and the second The common contact F2 is connected to the interconnection point P2 of the first and second switches Q1, Q2 via the first reactor 6. The combination of the third contact C and the second common contact F2 has a function equivalent to that of the third mode switch 15 in FIG. Therefore, the combination of the third contact C and the second common contact F2 can also be called third mode changeover switch means. Moreover, the combination of the 4th contact D and the 2nd common contact F2 has a function equivalent to the 4th mode switch 16 of FIG. Therefore, the combination of the fourth contact D and the second common contact F2 can also be called fourth mode changeover switch means. Further, the combination of the fifth contact E and the second common contact F2 has a function equivalent to that of the fifth mode switch 17 in FIG. Therefore, the combination of the fifth contact E and the second common contact F2 can also be referred to as fifth mode changeover switch means.

Since the first to fifth contacts A to E in FIG. 12 are turned on and off in the same manner as the first to fifth mode selector switches 13 to 17 in FIG. 4, the second embodiment shown in FIG. The same effects as those of the first embodiment can be obtained.

The present invention is not limited to the above-described embodiments, and for example, the following modifications are possible.
(1) The first to fourth switches Q1 to Q4 are made the same as the combination of the first to fourth switches Q11 to Q14 and the first to fourth diodes D11 to D14 made of the IGBT of FIG. Can be replaced. Further, the first to fourth switches Q1 to Q4 are similar to the combination of the first to fourth switches Qa to Qd and the first to fourth diodes Da to Dd made of the junction type transistors of FIG. Can be replaced.
(2) When the line between the AC power source 1 and the first and second switches Q1, Q2 or the line between the AC power source 1 and the first and second capacitors 7, 8 has an inductance The first reactor 6 can be omitted. Further, when the output line of the inverter including the third and fourth switches Q3 and Q4 has an inductance, or when the load 2 has an inductance, the second reactor 9 can be omitted.
(3) Only the first control mode (normal control mode) in FIG. 4 and the second control mode (frequency abnormal control mode) in FIG. 5 are required, and the third control mode (frequency and voltage value) in FIG. When the abnormal control mode) is not required, the storage battery 12 and the third mode switch 15 can be omitted. In the case of claim 1 corresponding to this modification, the fourth mode changeover switch 16 in FIGS. 4 and 5 is called third mode changeover switch means, and the fifth mode changeover switch 17 is in the fourth mode. This is called changeover switch means. In addition, a storage battery can be connected in parallel to the series circuit of the first and second capacitors 7 and 8 in this modification.
(4) Only the first control mode (normal control mode) in FIG. 4 and the third control mode (frequency and voltage value abnormal control mode) in FIG. 6 are required, and the second control mode (frequency abnormal in FIG. 5) is required. If the control mode is not required, the fourth mode changeover switch 16 can be omitted. In the case of claim 2 corresponding to this modification, the fifth mode changeover switch 17 of FIGS. 4 and 6 is called fourth mode changeover switch means.

It is a circuit diagram which shows the conventional single phase alternating current uninterruptible power supply. It is a circuit diagram which shows another conventional single phase alternating current uninterruptible power supply. It is a circuit diagram which shows another conventional single phase alternating current power converter device. It is a circuit diagram which shows the single phase alternating current uninterruptible power supply according to Example 1 of this invention in a normal control mode. It is a circuit diagram which shows the single phase alternating current uninterruptible power supply device according to Example 1 of this invention in a frequency abnormality control mode. It is a circuit diagram which shows the single phase alternating current uninterruptible power supply device according to Example 1 of this invention in a frequency and voltage value abnormality control mode. It is a circuit diagram which shows the control circuit of FIG. 4 in detail. It is a circuit diagram which shows the mode switching control circuit of FIG. 7 in detail. It is a wave form diagram which shows the state of each part of FIG. It is a wave form diagram which shows the state of each part of FIG. 4 when an alternating current power supply voltage is low. It is a wave form diagram which shows the state of each part of FIG. 4 when an alternating current power supply voltage is high. It is a circuit diagram which shows the single phase alternating current uninterruptible power supply device according to Example 2 of this invention in a normal control mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Loads 13-17 1st-5th mode switch Q1-Q4 1st-4th switch

Claims (5)

First and second power supply terminals for supplying an AC power supply voltage;
A series circuit of first and second capacitors;
A series circuit of first and second switches connected in parallel to the series circuit of the first and second capacitors to form a converter;
A series circuit of third and fourth switches connected in parallel to the series circuit of the first and second capacitors to form an inverter;
First mode changeover switch means (13 or A and F1) connected between the first power supply terminal and the interconnection point of the first and second capacitors;
Second mode changeover switch means (14 or B and F1) connected between the second power supply terminal and the interconnection point of the first and second capacitors;
Third mode changeover switch means (16 or D and F2) connected between the first power supply terminal and the interconnection point of the first and second switches;
Fourth mode changeover switch means (17, or E and F2) connected between the second power supply terminal and the interconnection point of the first and second switches;
A load connected between an interconnection point of the third and fourth switches and the second power supply terminal;
When the frequency and voltage value of the AC power supply voltage between the first and second power supply terminals are normal, the first and fourth mode changeover switch means are turned on, and the second and third mode changeover switch means When the frequency of the AC power supply voltage is abnormal and the voltage value is normal, the first and fourth mode changeover switch means are turned off and the second and third mode changeover switch means A mode switching control circuit for controlling ON,
A converter control circuit for controlling the first and second switches so as to convert the AC power supply voltage into a DC voltage;
An AC power supply apparatus comprising: an inverter control circuit that controls the third and fourth switches so as to apply an AC voltage having a desired frequency and a desired voltage value to the load. First and second power supply terminals for supplying an AC power supply voltage;
A series circuit of first and second capacitors;
A series circuit of first and second switches connected in parallel to the series circuit of the first and second capacitors to form a converter;
A series circuit of third and fourth switches connected in parallel to the series circuit of the first and second capacitors to form an inverter;
A storage battery having one end and the other end for supplying a DC voltage, the one end being connected to one end of a series circuit of the first and second capacitors;
First mode changeover switch means (13 or A and F1) connected between the first power supply terminal and the interconnection point of the first and second capacitors;
Second mode changeover switch means (14 or B and F1) connected between the second power supply terminal and the interconnection point of the first and second capacitors;
Third mode changeover switch means (15, or C and F2) connected between the other end of the storage battery and the interconnection point of the first and second switches;
Fourth mode changeover switch means (17, or E and F2) connected between the second power supply terminal and the interconnection point of the first and second switches;
A load connected between an interconnection point of the third and fourth switches and the second power supply terminal;
When the frequency and voltage value of the AC power supply voltage between the first and second power supply terminals are normal, the first and fourth mode changeover switch means are turned on, and the second and third mode changeover switch means And the first and fourth mode changeover switch means are turned off and the second and third mode changeover switch means are turned on when both the frequency and voltage value of the AC power supply voltage are abnormal. A mode switching control circuit to control;
The AC power supply voltage is converted to a DC voltage when the frequency and voltage value of the AC power supply voltage between the first and second power supply terminals are normal, and the frequency and voltage value of the AC power supply voltage are both abnormal. A converter control circuit for controlling the first and second switches so as to convert a DC voltage of the storage battery into a DC voltage required by a series circuit of the first and second capacitors;
An AC power supply apparatus comprising: an inverter control circuit that controls the third and fourth switches so as to apply an AC voltage having a desired frequency and a desired voltage value to the load. First and second power supply terminals for supplying an AC power supply voltage;
A series circuit of first and second capacitors;
A series circuit of first and second switches connected in parallel to the series circuit of the first and second capacitors to form a converter;
A series circuit of third and fourth switches connected in parallel to the series circuit of the first and second capacitors to form an inverter;
A storage battery having one end and the other end for supplying a DC voltage, the one end being connected to one end of a series circuit of the first and second capacitors;
First mode changeover switch means (13 or A and F1) connected between the first power supply terminal and the interconnection point of the first and second capacitors;
Second mode changeover switch means (14 or B and F1) connected between the second power supply terminal and the interconnection point of the first and second capacitors;
Third mode changeover switch means (15 or C and F2) connected between the other end of the storage battery and the interconnection point of the first and second switches;
A fourth mode changeover switch means (16, or D and F2) connected between the first power supply terminal and the interconnection point of the first and second switches;
Fifth mode changeover switch means (17 or E and F2) connected between the second power supply terminal and the interconnection point of the first and second switches;
A load connected between an interconnection point of the third and fourth switches and the second power supply terminal;
When the frequency and voltage value of the AC power supply voltage between the first and second power supply terminals are normal, the first and fifth mode changeover switch means are controlled to be turned on, and the second, third and fourth modes are controlled. When the changeover switch means is turned off, and when the frequency of the AC power supply voltage is abnormal and the voltage value is normal, the first, third and fifth mode changeover switch means are turned off and the second and second modes A mode switching control circuit for turning on the mode switching switch means;
When the voltage value of the AC power supply voltage between the first and second power supply terminals is normal, the AC power supply voltage is converted into a DC voltage, and when one or both of the frequency and voltage value of the AC power supply voltage are abnormal, A converter control circuit for controlling the first and second switches so as to convert a DC voltage of the storage battery into a DC voltage required by a series circuit of the first and second capacitors;
An AC power supply apparatus comprising: an inverter control circuit that controls the third and fourth switches so as to apply an AC voltage having a desired frequency and a desired voltage value to the load. Furthermore, it has the 1st reactor connected to the interconnection point of the said 1st and 2nd switch, and the 2nd reactor connected to the interconnection point of the said 3rd and 4th switch. The AC power supply device according to claim 1, 2, or 3.   4. The AC power supply apparatus according to claim 2, further comprising a charging unit that charges the storage battery.

Images