JPH0833233A - Ac/dc uninterruptible power supply - Google Patents

Abstract

PURPOSE:To eliminate the need of an intricate inverter by a constitution wherein power is received from an AC commercial power supply and a battery is charged and a DC/DC converter regulates the DC output of the battery from the peak value of the rated voltage of AC commercial power supply to a level within a range of specific % before outputting the power. CONSTITUTION:A DC/DC converter Conp converts the DC voltage of a battery Batt to produce a constant voltage. The converted voltage V. is regulated not to drop 20% or more from the peak value sq. rt. 2X100 volt of a commercial power supply voltage Vi. When the converted voltage Vd exceeds the peak value sq. rt. 2X100 significantly the breakdown voltage of the components constituting the electronic circuit in a load Load may exceed to cause deterioration of the reliability. Consequently, the upper limit of Vd is restricted within 110% of the peak value while taking account the 10% upper limit in the fluctuation of commercial power supply. The allowable range of fluctuation in the converted voltage Vd is preferably set from 110% to 80% of sq. rt. 2X100 volt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an uninterruptible power supply device for supplying a load such as a computer. More specifically, the present invention relates to an AC / DC uninterruptible power supply that constantly supplies power with commercial AC power output and supplies DC power from an internal battery during a power failure.

[0002]

2. Description of the Related Art A conventional uninterruptible power supply outputs only alternating current. That is, the apparatus is provided with a battery and an inverter for converting its DC output into AC, and either the AC output converted by the inverter or the commercial AC input to the apparatus is supplied to the load. The configuration of this device is shown in FIG. V _i is an AC power supply of the commercial. BATT is a battery that provides a power source to be supplied in the event of a power failure. CH is a charger that receives the output of the commercial AC power supply and charges the battery BATT. C _ONP
Is a DC / DC converter that adjusts the DC voltage of the battery BATT to the operating voltage of the inverter INV, for example, 300 volts. A chopper circuit is generally used for this DC / DC converter C _ONP . INV is an inverter. C ₁ and C ₂ are capacitors and a battery BA
The TT DC voltage of 300 V is divided. The voltage at point X is at a potential of 150 volts. Semiconductor switches Q ₁ , Q ₂
Is a transistor, for example, which is turned on / off by a signal from the outside. When the semiconductor switch Q ₁ is turned on, the potential at the point P becomes the positive side potential of the DC / DC converter C _ONP , and when the semiconductor switch Q ₂ is turned on, the point P becomes the negative side potential. Semiconductor switch Q ₁ ,
If Q ₂ is turned on and off at 50 Hz, for example, point XP
An alternating voltage of 50 Hz is obtained in between. When the voltage at the point X-P is applied to the filters L _ac and C _ac , an AC voltage with few harmonics is obtained between the points X and Y. S is a changeover switch. LOAD is a load and is a small computer such as a personal computer or a workstation. There is a rectifier circuit of diodes D _{L1 to} D _L4 inside, which charges the capacitor C _L with the output thereof and the switching converter C _ONL.
Work. The computer circuit such as an electronic circuit is _{operated by} the output of C _ONL . When the power is received from the commercial AC power supply V _i , the changeover switch S is switched to the commercial side to supply the load LOAD with the AC voltage V _i . When there is a power failure, the selector switch S is switched to the inverter side and the voltage V ₀
Power the OAD. In this way, the load L
AC power is supplied to the OAD. If the power capacity of the charger CH is increased, the inverter can also supply power to the load LOAD when receiving commercial power.

FIG. 10 shows a pattern of an AC voltage and a current flowing through a load LOAD. Since the capacitor C _L in LOAD at the level of the voltage V _d charge is stored, the current flows only to the AC voltage is higher than the voltage V _d period. Therefore, this current I _ac has a pulse shape. The voltage of the capacitor C _L of the load LOAD, that is, the DC voltage V _d supplied to the converter C _ONL , is a voltage obtained by rectifying the AC input voltage (absolute value of V _i ) during the period T _on during which the input current I _ac is flowing.
Equal to the level of V _max and the maximum value V _max is reached. Also the current I
During the period T _{off when ac} is not flowing, the capacitor C _L
Discharges exclusively and its voltage V _d drops to a minimum value V _min . Thus, the voltage V _d of the capacitor C _L is V _max
Fluctuates between V _min and V _min . V _max is the maximum amplitude value (peak value) of the AC input voltage V _i (V ₀ ), and
V _min depends on the capacity of the capacitor C _L , but is 1 from V _max
It will be about 0% lower level. The AC input voltage normally assumes a fluctuation of ± 10% with respect to a nominal value (for example, 100V), and the load LOAD is designed to withstand this fluctuation. In this case, V _max is (√2 × nominal value) ± 1
It varies in the range of 0%. Also, V _min is 10 than V _max
%, So the fluctuation range is (√2 x nominal value)
It becomes + 0% and -20%. That is, the DC voltage V _d on the load LOAD side is allowed to drop to about 20% of the peak value of the nominal voltage of the AC input. The drawback of this prior art is that it requires an inverter to convert the DC power of the battery BATT into AC. The circuit is complicated and impairs reliability. In addition, the cost becomes high. Since the inverter INV passes a high pulse current, the DC / DC converter C _ONP needs a large output capacity corresponding to this. This is also a factor that increases costs.

[0004]

SUMMARY OF THE INVENTION The present invention has been proposed in order to improve the above-mentioned drawbacks, and an object thereof is to realize an uninterruptible power supply with a simple structure to improve reliability and reduce cost. Especially. In addition, downsizing of the device is also realized. Small computers such as personal computers and workstations once convert the received AC power to DC power and then convert it to a low voltage of 5V, 2V, etc. required by electronic circuits such as semiconductor ICs with a DC / DC converter. To operate the device. Therefore, the power supplied from the outside may be a DC voltage as long as the required level is secured. The present invention aims to realize an uninterruptible power supply device that supplies DC power by making use of this actual usage.

[0005]

In order to achieve the above object, (1) the present invention is an AC power received from a commercial AC power supply,
In an AC / DC power supply device that selects and outputs one of DC power from a built-in DC power supply with a selector switch, the DC power supply device is connected to the AC power supply, and is connected to the charger. A battery and a DC / DC converter, the charger receives power from the commercial AC power source, charges the battery with a DC voltage output from the commercial AC power source, and the DC / DC converter outputs the DC output from the battery. A feature of the invention is an AC / DC uninterruptible power supply that adjusts and outputs a level in a range of 110 to 80% of a peak value of a nominal voltage of a commercial AC power supply. (2) The present invention provides a DC power supply device, an insulating transformer connected to an AC power supply, a rectifier for rectifying the output of the insulating transformer, a DC / DC converter connected to the output side of the rectifier, and the rectifier output side. And a battery connected via a switch constituting the DC / DC converter, the DC / DC converter receives power from the commercial AC power source via the insulation transformer and the rectifier, and outputs the DC voltage at the output. A feature of the invention is an AC / DC uninterruptible power supply device according to (1), which charges a battery and adjusts and outputs the DC output of the battery when the commercial AC power supply fails. (3) According to the present invention, a DC power supply device has a first semiconductor switch and is connected to an AC power supply, and a DC / DC converter connected via the first semiconductor switch.
The DC / DC converter includes a battery connected to the DC / DC converter, and the DC / DC converter has a second semiconductor switch, a reactor and a capacitor connected in a loop, and one of the second semiconductor switches has a diode. Connected to one pole of the changeover switch, the other is connected to the other pole of the changeover switch, the charger receives the power of the commercial AC power supply from the load side after the changeover switch, the output The invention is characterized by the AC / DC uninterruptible power supply device according to (1), in which the battery is charged with the DC voltage, and the DC / DC converter adjusts and outputs the DC output of the battery. (4) The present invention uses a relay as a changeover switch for supplying AC or DC to the load, and the commercial AC power supply line and the DC power supply line are both disconnected (1) or (2) or ( A feature of the invention is the AC / DC uninterruptible power supply described in 3). (5) The present invention uses a relay having an a contact and a b contact as a changeover switch for supplying AC or DC to a load, uses the a contact as a switch of a commercial AC power supply system, and uses the b contact as a DC power supply. An AC / DC uninterruptible power supply device according to (1) or (2) or (3) or (4), which is used as a system switch and drives the exciting coil of the relay by the commercial AC power supply. .

[0006]

According to the present invention, since a complicated inverter can be removed from the uninterruptible power supply, it is possible to obtain a small-sized AC / DC uninterruptible power supply with low cost and high reliability.

[0007]

FIG. 1 shows an embodiment of the present invention. (Corresponding to Claim 1) FIG. 2 shows an example of the operating voltage and current waveforms. V _i is a commercial AC power supply and has a nominal voltage, for example, a sine wave voltage of 100 V (peak value is √2 × 100 V). In the figure,
V _i is a commercial AC power source, CH is a charger, BATT is a battery, C _ONP is a DC / DC converter, S is a changeover switch, LOAD is a load, D _{L1 to} D _L4 are diodes,
C _L indicates a capacitor and C _ONL indicates a switching converter. CH is a charger to charge the battery BATT.
C _ONP is a DC / DC converter that converts the DC voltage of the battery BATT and converts it into a constant voltage. This converted voltage V
The level of _d is adjusted so that the drop does not exceed 20% of the peak value √2 × 100 V of the commercial power supply voltage V _i . Further, if the converted voltage V _d greatly exceeds the peak value √2 × 100 V, there is a risk of exceeding the withstand voltage of the components forming the electronic circuit in the load LOAD and lowering the reliability, so the upper limit of V _d is a commercial value. The maximum value of 10%, which is the upper limit of the fluctuation of the power supply, is expected, and the corresponding peak value of 11
Keep it at 0% level. Therefore, the allowable fluctuation value of the converted voltage V _d is preferably within a range of 110 to 80% of √2 × 100 volts.

When power is being received from the commercial power source, the changeover switch S is set to the commercial power source side and the load LO is applied at the voltage V _i.
Power AD. In the rectifying circuit of the load LOAD, the pairs of diodes D _L1 , D _L4 and D _L2 , D _L3 are alternately energized to convert the input AC power into DC. This voltage and current waveform is shown in Fig. 2.
It is (a). During the power failure period, the changeover switch S is switched to the DC side to supply the load LOAD with the DC output voltage of the DC / DC converter C _ONP . In the rectifier circuit of the load LOAD, only the diode pair D _L1 and D _L4 are continuously energized to charge the capacitor C _L , and the switching converter C _ONL
To operate.

FIG. 2B shows a pattern of voltage and current to be supplied. A pulsed high-level current flows intermittently during AC power supply (FIG. 2A), while a low-level current continuously flows during DC power supply. A continuous current flows through the diodes D _L1 and D _L4 of the load LOAD, but since the level is low, there is no problem such that the temperature rises abnormally. Since the value of the output direct current is small, the capacity of the DC / DC converter C _ONP may be small. Conventional example (Fig. 9)
The DC / DC converter C _ONP requires a large capacity for the inverter INV to pass a high pulse current.

FIG. 3 shows an example of the configuration in which one relay is used as the changeover switch S used in the present invention. (Corresponding to claims 3 and 4) A switch is provided on either pole of the two power supply lines. One pole of the commercial power supply may be grounded for security purposes.
If the AC power supply system and the DC power supply system are connected even with one wire,
If the DC power system fails for some reason such that one pole is grounded, leakage current or short-circuit current may flow, which may be dangerous. In order to avoid this danger, a switch is provided on both electrode sides so that a loop through which leakage current or short-circuit current flows is not formed. As will be described later, insulation is taken so that the DC power supply does not communicate with the AC power supply system via the charger in a DC manner. Even if a grounding accident occurs on the load LOAD side by the procedure of floating the DC power supply from the ground, the problem of leakage current or short-circuit current can be avoided. One of the switches S may be provided as a power supply function. That is, if there is no problem in terms of security, either one of the switches X, X or Y, Y provided on both poles of the power supply may be directly connected. There is a difference in voltage level between the commercial AC power supply system and the DC power supply system, and if they are connected in parallel, an excessive current may flow and cause a failure. The occurrence of this problem is prevented by preventing a period in which both switches are closed at the same time. That is, power is supplied using a-contacts X and Y for the commercial AC power supply system and b-contacts X and Y for the DC system. According to this, since the contacts X 1 and X 2 or Y 1 and Y 2 do not close at the same time, it is possible to avoid a situation where an overcurrent occurs on both power supply sides. Even if each of the contacts X, X , Y, and Y is composed of an individual relay, the same purpose can be achieved by forming a sequence so that X and X or Y and Y do not close at the same time. Note that the above method can be applied to any of the first to third embodiments.

FIG. 4 is a structural example of a charger for charging the battery BATT. FIG. 4 (a) shows an AC input with a rectifier R _ec.
It is a charger that rectifies once to obtain a direct current, and converts this direct current power into a desired level of the battery BATT again by a switching converter. The switching converter is a buck-boost type that has been used conventionally. Reactor L ₁ is 2
It has a secondary winding. When the semiconductor switch Q _c1 is turned on, the voltage of the capacitor C _dc is applied to the primary winding of the reactor L ₁ and current begins to flow. As a result, electromagnetic energy is stored in the reactor L ₁ . When Q _c1 is turned off, a voltage having the illustrated polarity is induced in the secondary winding of the reactor L ₁ and a current flows through the diode D ₁ . The ratio of the ON period and the OFF period of the semiconductor switch Q _c1 is controlled to obtain a constant DC voltage. The battery BATT is charged with this DC output voltage. The reactor L ₁ insulates between input and output.

In FIG. 4B, a commercial frequency isolation transformer T ₁ is provided at the AC input end. The voltage induced on the secondary side of the transformer T ₁ is converted into a DC voltage by the rectifier R _ec , and this is adjusted to the voltage level desired by the battery BATT by the step-down chopper. When turning on the semiconductor switch Q _c2 current flows through the reactor L _2, energy is stored in reactor L _2. When the semiconductor switch Q _c2 is turned off, the energy of the reactor L ₂ is discharged through the loop of the diode D ₂ . The ratio of the ON period and the OFF period of the semiconductor switch _Qc2 is controlled to obtain a desired DC voltage. The transformer T ₁ on the input side insulates between input and output. If there is no need for insulation, the transformer T ₁ is omitted and the part on the right side of the broken line cd is used as a charger. The power capacity of the insulating transformer T ₁ is sufficient to charge the battery BATT, and it is not necessary to have the power supply capacity to the load LOAD.

As the battery BATT, a lead sulfate battery is used. The voltage of one of these batteries is at most 2 volts, and it is unavoidable to connect them in series to increase the overall voltage. Capacity required for power supply (ampere hour A
Even if H) is the same, reliability is lowered when a large number of small-capacity batteries (having a small AH) are connected in series to increase the voltage, and the cost is increased due to division loss. Further, if the voltage is too high, it is necessary to take measures for ensuring the safety of handling, which also increases the cost. Therefore, in the present invention, a small number of batteries having a large AH are used, and the voltage level required for power supply to the load is boosted by the DC / DC converter.

FIG. 5 shows the voltage of the battery BATT as a load L.
This is a configuration example of a DC / DC converter C _{ONL that} converts to a voltage level desired by OAD, and is an example using a step-up chopper with no input / output isolation. When the semiconductor switch Q _c3 is turned on, the voltage of the input battery BATT is applied to the reactor L ₃ and a current flows, whereby energy is stored. During this period, the power supply is supplied by discharging the capacitor C _d . When the semiconductor switch Q _c3 is turned off, the current in the reactor L ₃ passes through the diode D ₃ and becomes an output. At this time, the voltage of the input battery BATT is added with the voltage of the polarity of the reactor L ₃ shown in the figure, so that the output voltage becomes higher than the input voltage. The desired DC output voltage is obtained by adjusting the ratio of the ON period and the OFF period of the semiconductor switch _Qc3 . When an isolated switching converter is required, the configuration on the right side of the broken line ab of the charger is used in FIG. The voltage level is the primary of reactor L ₁ ,
The accuracy of the constant voltage is improved by roughly adjusting the winding ratio of the secondary winding and by turning on and off the semiconductor switch Q _c1 .

A feed-forward converter is also used as the switching converter. This is shown in FIG.
When the semiconductor switch Q _c4 is turned on, a voltage of the illustrated polarity is induced in the transformer T ₂ and electric power is sent to the output side. When the semiconductor switch Q _c4 is turned off, the transformer T
A voltage having a polarity opposite to that shown in the drawing is induced by the excitation energy stored in ₂ , and electromagnetic energy is returned from the winding n to the battery BATT on the input side via the diode D ₄ . During the off period of the semiconductor switch Q _c4 , the electromagnetic energy stored in the smoothing reactor L ₄ is transferred to the diode D.
It flows through route ₅ and is applied to power supply. A desired DC voltage is obtained by adjusting the on / off ratio of the semiconductor switch Q _c4 . To combine the charger and switching converter, at least one of them must have an insulation function. For example, when the non-isolated step-down chopper of FIG. 5 is used as the switching converter, the charger with the transformer of FIG. 4A or 4B is combined.

FIG. 7 shows a second embodiment of the present invention. In the embodiment of (claims 2 to the corresponding) 1, 4 and reactor L ₃ in the case of adopting the (b), the reactor L ₃ in the case of adopting the Figure 5 as a DC · DC converter C _ONP as a charger CH And are shared with each other for simplification. In FIG. 7, except the diode D ₆ and the semiconductor switch Q _c6 , the charger is the same as the charger in FIG. 4B, and this portion operates during the period when the commercial AC power source is active to charge the battery BATT. Also,
Except for the semiconductor switch Q _c5 and the diode D ₇ , it becomes the same as the converter of FIG. 5 and operates when the battery is discharged during a power failure. This operation is as follows.

While the power is being received from the commercial power source, the changeover switch S is set to the commercial power source side to supply the load LOAD with the AC voltage V _i . During this time, the battery BATT is charged as follows. The insulating transformer T ₃ receives the AC voltage V _i, and the voltage generated on the secondary side is rectified by the diode rectifier R _ec ,
The pulsating voltage is smoothed by the smoothing capacitor C _dc . The voltage of the capacitor C _dc is stepped down by the on / off switching of the semiconductor switch Q _c5 and adjusted to a constant voltage to charge the battery BATT. When turning on the semiconductor switch Q _c5 voltage of the capacitor C _dc is applied to the smoothing filter L _5, C _b. A voltage is applied to the reactor L ₅ with the polarity shown,
The flowing current increases. That is, electromagnetic energy is stored in L ₅ . Next, when the semiconductor switch Q _c5 is turned off, the current flowing in the reactor L ₅ circulates through the diode D ₇ . The circulating current gradually decreases. Reactor L
The voltage of ₅ is the opposite of the one shown and releases the stored electromagnetic energy. The ratio of the ON period and the OFF period of this semiconductor switch Q _c5 is adjusted by a signal from a control device (not shown in the figure) to maintain the voltage of the capacitor C _b at a desired level. With the voltage of this capacitor C _b , the battery BATT
To charge.

During the power failure of the commercial power supply, the operation is as follows.
The input of the isolation transformer T ₃ is gone and the battery BAT
The charging function of T is stopped. The changeover switch S is switched to the battery side to supply the load LOAD with the DC voltage V ₀ . The voltage V ₀ of the capacitor C _dc is adjusted to be constant as follows. The semiconductor switch _Qc5 is turned off. When the semiconductor switch Q _c6 is turned on, the battery B
The voltage of ATT is applied to the reactor L ₅ with the opposite polarity to that shown, and the flowing current increases. That is, electromagnetic energy is stored. Next, when the semiconductor switch Q _c6 is turned off,
The current flowing through the reactor L ₅ flows through the diode D _{6 toward} the capacitor C _dc side. The polarity of the voltage of the reactor L ₅ at this time is the same as that shown in the figure, and the sum of the voltage of the reactor and the voltage of the battery BATT becomes the voltage V ₀ for charging the capacitor C _dc . That is, the voltage V ₀ is the battery BAT
The voltage is boosted to a level higher than the voltage of T. The ratio of the ON period and the OFF period of the semiconductor switch Q _c6 is adjusted to keep the voltage V ₀ at a desired level, that is, within the range of 110 to 80% of the peak value of the commercial AC power supply nominal voltage. When the commercial power supply recovers from the power failure, the changeover switch S is switched to the commercial power supply side to supply power with the AC voltage V _i .

FIG. 8 shows a third embodiment of the present invention. (Corresponding to claim 3) In the present invention, the charging device receives power from points a and b on the load side of the changeover switch S. As a result, the insulating transformer used in the embodiment of FIG. 7 is omitted. Also in this case, the DC power supply system is separated (insulated) from the commercial power supply system by the changeover switch S during the power feeding period. Charger running during a period in which the receiving power from the commercial power source, the rectifier R _ec, the capacitor C _dc, semiconductor switches Q _c7, diode D _8, which is a combination of the reactor L _5. This corresponds to the right side of the broken line cd in FIG. The converter that operates during a power failure is reactor L ₅ , semiconductor switch Q _c8 , diode D
It is a combination of _nine . This corresponds to the converter of FIG. During this period, the semiconductor switch _Qc7 is turned off and the loop of the current flowing from the points a and b is cut off. Next, the operation will be described.

While the power is being received from the commercial power source, the changeover switch S is set to the commercial power source side to supply the load LOAD with the AC voltage V _i . Further, the battery BATT is charged during this period. The AC voltage V _i received from ab after the changeover switch S is rectified by the diode rectifier R _ec , and the pulsation is smoothed by the smoothing capacitor C _dc . _Turn on the semiconductor switch Q _c7
The voltage of the capacitor C _dc is stepped down by off switching and adjusted to a constant level to charge the battery BATT. The semiconductor switch _Qc8 is kept off. While the semiconductor switch Q _c7 is on, the capacitor C _dc
Is applied to the smoothing filters L ₅ and C _b , and this output charges the battery BATT. A voltage of the illustrated polarity is induced in L _5, and the stored electromagnetic energy increases as the current increases. Next, when the semiconductor switch Q _c7 is turned off, the current flowing in L ₅ circulates through the diode D ₈ . As a result, the electromagnetic energy of L ₅ is released to the capacitor C _b and the battery BATT. By changing the ratio of the ON and OFF periods of the semiconductor switch, the voltage of the capacitor C _b , that is, the battery B
Adjust the charging voltage of ATT.

When the commercial power supply fails, the changeover switch S
Is switched to the DC power source side, and the load LOAD is supplied with the voltage V ₀ of the capacitor C _d . The semiconductor switch _Qc7 is turned off to cut off the inputs from the terminals a and b. Since the voltage of the battery BATT is lower than V ₀ , the voltage is boosted in the next switching operation. When the semiconductor switch Q _c8 is turned on, the voltage of the battery BATT is applied to the reactor L ₅ with a polarity opposite to that shown in the figure, and the current flowing there is increased. Along with this, the stored electromagnetic energy increases. Next, when the semiconductor switch Q _c8 is turned off, the voltage of the reactor L ₅ is added to the voltage of the battery BATT, and the boosted voltage V ₀ is obtained. The ratio of the on / off period of the semiconductor switch Q _c8 is adjusted to keep the level of the output voltage V ₀ within the range of 110 to 80% of the peak value of the commercial AC power supply nominal voltage. Signals for turning on and off the semiconductor switches Q _c7 and Q _c8 are _output from a control device (not shown). Although a bipolar transistor is shown as a semiconductor switch, another switch such as an IGBT (Insulated Gate Bipolar) is used.
Transistor) and power MOS / FET can be used in the same way.

[0022]

According to the present invention, a complicated inverter can be removed from the uninterruptible power supply, which makes it possible to realize a highly reliable, low-cost, and small AC / DC uninterruptible power supply. By disconnecting the commercial AC power supply side and the DC power supply side with an insulating transformer or changeover switch, even if a grounding accident occurs on the commercial AC power supply side or the load side, dangerous current will not flow to the grounding side, so the device can be safely installed. Can be operated. The second embodiment shown in FIG. 7 has a structure in which the number of heavy and expensive reactors is reduced, which is effective in reducing the weight and cost of the apparatus. In the third embodiment shown in FIG. 8, since the insulating transformer, which is large and heavy, is omitted from the configuration, it is effective in further downsizing the device or reducing the cost. The device of the present invention is compact and suitable for mounting on a rack. Therefore, this device can be mounted on the same rack in combination with a computer mounted and used on the rack in the field of FA (Factory Automation), which is useful in terms of space saving.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention.

FIG. 2 shows operating voltage and current waveforms, (a) and (b).
Is the waveform of each part.

FIG. 3 shows an example of a changeover switch which is one of the embodiments of the present invention.

FIG. 4 shows a configuration of a charger which is one of the embodiments of the present invention, and (a) and (b) respectively show other examples.

FIG. 5 shows a configuration example of a DC / DC converter which is one of the embodiments of the present invention.

FIG. 6 shows a configuration example of a switching converter which is one of the embodiments of the present invention.

FIG. 7 shows a second embodiment of the present invention.

FIG. 8 shows a third embodiment of the present invention.

FIG. 9 shows a conventional example.

FIG. 10 shows a pattern of an AC voltage and a current flowing through a load, and (a) and (b) are voltages or currents flowing through respective portions.

[Explanation of symbols]

V _i commercial AC power source BATT Battery CH charger C _ONP DC · DC converter INV inverter Q ₁ semiconductor switch Q ₂ semiconductor switches Q _c1 semiconductor switch Q _c2 semiconductor switch Q _c3 semiconductor switch Q _c4 semiconductor switch Q _c5 semiconductor switch Q _c6 semiconductor Switch Q _c7 Semiconductor switch Q _c8 Semiconductor switch L _ac filter C _ac filter S selection switch LOAD load D _L1 diode D _L2 diode D _L3 diode D _L4 diode D ₁ diode D ₂ diode D ₃ diode D ₄ diode D ₅ diode D ₆ diode D ₇ diode D ₈ diode D ₉ diode C _ONL switch converter C _b capacitor C _d capacitor C _dc capacitor V _d voltage R _ec rectifier L ₁ reactor L ₂ reactor L ₃ reactor L ₄ reactor L ₅ reactor T ₁ transformer T ₂ transformer T ₃ transformer

Claims (5)

[Claims] 1. AC power received from a commercial AC power supply,
In an AC / DC power supply device that selects and outputs one of DC power from a built-in DC power supply with a selector switch, the DC power supply device is connected to the AC power supply, and is connected to the charger. A battery and a DC / DC converter, the charger receives power from the commercial AC power source, charges the battery with a DC voltage output from the commercial AC power source, and the DC / DC converter outputs the DC output from the battery. An AC / DC uninterruptible power supply characterized by adjusting and outputting to a level in the range of 110 to 80% of the peak value of the nominal voltage of a commercial AC power supply. 2. The DC power supply device comprises an insulating transformer connected to an AC power supply, a rectifier for rectifying the output of the insulating transformer, a DC / DC converter connected to the output side of the rectifier, and an output side of the rectifier. , A battery connected via a semiconductor switch constituting the DC / DC converter, the DC / DC converter receives power from the commercial AC power source via the insulation transformer and a rectifier, and outputs the DC voltage at its output. The AC / DC uninterruptible power supply device according to claim 1, wherein the battery is charged, and the DC output of the battery is adjusted and output when the commercial AC power supply fails. 3. The DC power supply device comprises a charger having a first semiconductor switch and connected to an AC power supply, and a DC / DC converter connected via the first semiconductor switch.
The DC / DC converter includes a battery connected to the DC / DC converter, and the DC / DC converter has a second semiconductor switch, a reactor and a capacitor connected in a loop, and one of the second semiconductor switches has a diode. Connected to one pole of the changeover switch, the other is connected to the other pole of the changeover switch, the charger receives the power of the commercial AC power supply from the load side after the changeover switch, the output 2. The AC / DC uninterruptible power supply according to claim 1, wherein the DC / DC converter regulates and outputs the DC output of the battery by charging the battery with the DC voltage. 4. A relay is used as a changeover switch for supplying AC or DC to the load, and the commercial AC power line and the DC power line are both disconnected from each other. Alternatively, the AC / DC uninterruptible power supply device described in 3. 5. A relay having an a contact and a b contact is used as a changeover switch for supplying alternating current or direct current to a load, the a contact is used as a switch of a commercial alternating current power supply system, and the b contact is a direct current power supply system. 5. The AC / DC uninterruptible power supply according to claim 1, wherein the commercial AC power supply drives the exciting coil of the relay.