JP2673921B2 - Uninterruptible power system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration of an uninterruptible power supply (hereinafter referred to as UPS) and a rectifier having an active filter function.

[0002]

2. Description of the Related Art Electric equipment used by being connected to a commercial AC power source, such as a computer, an air conditioner for home electric appliances, and a television, has a low power factor, and the flowing current is distorted and contains a large amount of harmonic components. This is because a rectifier circuit having a non-linear characteristic is placed in the power receiving section of the electronic device. When this distorted wave current flows into the commercial AC power system, it distorts the sine wave voltage, causing malfunctions and failures in the phase advancing capacitors, relays, etc. connected to the system. There is a movement to regulate the harmonic current generated in the load in order to reduce the pollution of these harmonic currents. There are currently two methods for suppressing the flow of harmonic currents on the commercial power system side.
One is a method in which an active filter is provided in parallel with a load generating a harmonic current and the harmonic current generated in the load is bypassed to this filter. If the bypass effect is sufficient, all harmonic currents generated in the load will flow to the active filter, and the harmonic currents flowing to the power system side will be zero. Another method is to provide a rectifier circuit in a power receiving unit of an electronic device with a harmonic current suppressing function that does not generate a harmonic current, that is, a function that allows only a fundamental current to flow. The latter method may be flexible when a new electronic device is introduced, but the former active filter must be added to the existing electronic device. A device with a single function as an active filter has already been introduced. On the other hand, a U having an AC voltage output is connected to a device having a structure close to that of an active filter device.
There are rectifiers for PS and DC voltage output. However, these devices do not currently utilize the function of the active filter.

FIG. 7 shows an example of an active filter.
In the figure, 1 is a commercial AC power supply (a single-phase power supply is shown as an example, but the same is true for a three-phase power supply), 2 is a commercial load, 3 is a current transformer, and CONT is a control device. L _IN is an input reactor, S _{1 to} S ₄ are semiconductor switches, and C is a capacitor. The current transformer CT3 is a current i flowing through the commercial load 2.
_The signal SG _X is obtained by sensing _L. The structure of the active filter indicated by the broken line is a semiconductor switch element, for example, a bridge circuit composed of switches (S _{1 to} S ₄ ) in which transistors (Q _{1 to} Q ₄ ) and diodes (D _{1 to} D ₄ ) are connected in anti-parallel and input. It consists of a reactor L _IN and a DC capacitor C. A current transformer CT senses the input current i _F of the active filter to obtain a signal SG ₁ .
CONT is a control device that generates a signal for controlling ON / OFF of the switches S _{1 to} S ₄ . Since the commercial load 2 generally has a low fundamental wave power factor and also includes a harmonic current component, the current has a distorted waveform because the sine waveform is broken.

FIG. 8 shows the waveform of each current. (A)
Represents i _L , (b) represents i _R , and (c) represents i _S. The current i _L flowing through the commercial load 2 (an example of a general rectifier load) includes a large amount of pulsed harmonic current components, and the total power factor is low. This current i _L can be separated into a fundamental wave current i _{L1 in} phase with the voltage of the AC power supply 1 and a harmonic current component i _R. i _F is the input current waveform of the active filter.
i _S is the output current of the AC power supply 1. Only the fundamental wave current i _L1 of the commercial load current is made to flow from the AC power supply 1, that is, i _S = i _L1 , and the remaining harmonic current i _R is made to flow to the active filter. That is, control is performed so that i _F = −i _R. This is the function of the active filter.

FIG. 9 shows a conventional example of an AC uninterruptible power supply (UPS). Although the example is for a single-phase circuit, a three-phase circuit is also used. UPS is the input converter A
D, a battery B (here, a lead-acid battery will be described as an example of the energy converter), and an AC output conversion unit (hereinafter referred to as an inverter) DA. AD
C and DAC are control devices for the input conversion unit and the output conversion unit, respectively. The input converter AD is a so-called rectifier that performs AC / DC conversion, and has the same configuration as the active filter in FIG. 7. Newly added is PT _IN , which is a transformer that senses the voltage of the AC power supply. The output converter DA is a so-called inverter that performs DC / AC conversion. A bridge circuit composed of switches S _{5 to} S _{8 in} which a transistor and a diode are connected in antiparallel, and a reactor L
_{An AC} filter composed of _AC and a capacitor C _AC , and an output transformer T. PT _OUT is a transformer that senses the output voltage.

Next, the operation will be described. Switches S _{1 to} S ₄
The bridge circuit composed of rectifies the voltage of the AC power source to charge the capacitor C and the battery B, and supplies power to the inverter DA. If only rectifying, switch S
_{1 to} S ₄ can function only with a diode. A transistor connected in anti-parallel with the diode is provided to control the waveform of the input current. The purpose thereof is to set the power factor to 1 and suppress the generation of harmonics by making the input current of the device have a sine waveform in phase with the voltage of the AC power supply. When viewed from the AC power supply side, UPS is equivalent to a pure resistance and becomes an ideal load.

The current waveform control mechanism will be described below. For example, when the transistor of the switch S ₂ is turned on when the polarity of the AC power supply 1 is as shown in FIG. 9, all the voltage of the AC power supply 1 is applied to the reactor L _IN by a loop formed by the transistor of S ₂ and the diode of S _4. , Electromagnetic energy is stored by the current flowing through it. Next, when the transistor of the switch S ₂ is turned off, the current of the reactor L _IN flows through the diodes of the switches S ₁ and S ₄ and energy is released to the capacitor C side. The voltages of the AC power supply 1 and the reactor L _IN at the time of this energy release have the polarities shown in the figure, and the capacitor C is charged with the sum of the two voltages. Therefore, the voltage of the capacitor C is charged to a level equal to or higher than the peak value of the voltage of the AC power supply 1. (When the switches S _{1 to} S ₄ are composed only of diodes, the voltage of the capacitor C does not become higher than the peak value of the AC power supply 1). The magnitude of the current flowing through the reactor L _IN (Hence, the magnitude of the electromagnetic stored energy) can be adjusted by changing the time ratio of the on and off states of the transistors constituting the respective switches, reactor L _IN using this mechanism Make the waveform of the current flowing through the sine wave.

The controller ADC produces a sinusoidal reference signal based on the sinusoidal voltage signal SG _E from the transformer PT _IN, and follows the input current signal SG _I obtained from the current transformer CT to the reference signal. That is, the switches S _{1 to} S ₄ are controlled so that the current has a sinusoidal waveform. The voltage EC of the capacitor C is fed back to generate a reference signal whose amplitude is controlled so as to keep EC constant. Inverter DA
In, switches constituting the bridge circuit (S ₅ ~S ₈₎
An AC voltage is obtained by the switching operation of, and the voltage waveform is shaped into a sine wave by an AC filter composed of L _AC and C _AC , and power is supplied to the conversion load 4AC. When the AC power supply 1 fails, the discharge power of the battery B is converted by the inverter DA and the converted load 4AC is supplied with power. Therefore, the conversion load 4AC is supplied with power without interruption. The converter DAC is a switch S _{5 of the} inverter DA.
A control device that obtains a signal for controlling S ₈ takes out the output voltage of the inverter as a signal SG _OUT via a transformer PT _OUT , and generates a control signal based on the output voltage so that the power supply voltage to the conversion load 4AC becomes constant. To do.

[0009]

Although the recent UPS and rectifiers have a current control function for converting the input current waveform into a sine wave, it cannot be said that this function is fully utilized. Further, in the UPS and the rectifying device during the period in which the AC power source is out of power, only the respective batteries B and the output side are operating, and the input conversion unit is in a closed state. The purpose of the present invention is
The input current control function of the UPS or the rectifier is used as an active filter, and the harmonic current generated in another commercial load is bypassed so as not to flow to the commercial AC power supply side. In addition, the input conversion unit is utilized even during a power failure of the AC power supply to increase the power supply capacity of the UPS and rectifier. That is, the conversion load, which is the original load, is supplied with power, and at the same time, the input conversion unit of the UPS or the rectifier is used as an inverter to supply power to the commercial load.

[0010]

In order to achieve the above object, the present invention provides a power supply device which is connected in parallel with a commercial load and receives power from an AC power supply via a common switch. The device consists of a bidirectional converter capable of converting AC power into DC power and DC power into AC power, a battery connected to the DC output of this bidirectional converter, and also its input side. The bidirectional converter is equipped with an inverter that operates by being connected to the DC output and a battery, the AC input side of the bidirectional converter is connected to the AC power supply and a commercial load, and the inverter converts the AC power converted by itself to AC power. Power is supplied to the conversion load, and the switch is used when the AC power supply is capable of supplying power, and is open during a power failure. The control device for controlling the function generates two control signals, the first control signal of which is generated during the period when the AC power is being supplied, and its own AC input current and DC output of the bidirectional converter. The voltage and the current flowing in the commercial load are respectively sensed and signal-input to the control device to control the DC output voltage to a predetermined voltage level, and the AC input current corresponding to the DC output voltage. Is a control signal for shaping the waveform of sine wave into a sine wave and allowing only a harmonic current component of the current flowing in the commercial load to flow into the bidirectional converter. The second control signal is a control signal for the AC power supply. It is generated during a power outage, and senses the AC voltage output by itself on the AC side of the bidirectional converter to convert the DC power of the battery to the desired constant frequency constant voltage. The control device for the inverter outputs a control signal for sensing the AC output voltage of the inverter and converting the AC output voltage to a desired constant frequency constant voltage of the conversion load. And an uninterruptible power supply "
“A power supply device that is connected in parallel with a commercial load and that receives power from an AC power supply through a common switch. This power supply device converts AC power to DC power and also converts DC power to AC power. It is also equipped with a bidirectional converter that can also be operated, a battery connected to the DC output of this bidirectional converter, and a DC-DC converter that operates by connecting the input side to the DC output of the bidirectional converter and the battery. The AC input side of the bidirectional converter is connected to the AC power source and a commercial load, and the DC-D
The C converter supplies the DC power converted by itself to the DC conversion load, and the switch is used in a state where it is closed when the AC power supply can supply power and is open during a power failure to control the power conversion function of the bidirectional converter. The control device generates two control signals, the first control signal of which is generated while the AC power source is supplying power, and includes the AC input current and DC output voltage of the bidirectional converter, and A signal is input to the control device by sensing each of the currents flowing in the commercial load, the DC output voltage is controlled to a predetermined voltage level, and the waveform of the AC input current corresponding to the DC output voltage is obtained. Shaped into a sine wave,
Further, it outputs a control signal for causing only the harmonic current component of the current flowing in the commercial load to flow into the bidirectional converter, and the second control signal is a period during which the AC power supply is out of power. The DC-DC is a control signal that is generated by the DC-DC converter and senses the AC voltage output to the AC side of the bidirectional converter to convert the DC power of the battery into a desired constant-frequency constant-voltage AC voltage.
The gist of the invention is "the converter control device senses the DC output voltage of the DC-DC converter and outputs a control signal to make the DC constant voltage desired by the conversion load."

[0011]

According to the present invention, the converter forming the input converter AD of the uninterruptible power supply unit can perform bidirectional power conversion from AC to DC or from DC to AC, and can also control harmonic current. By using a bidirectional converter, power can be supplied to the commercial load even when the AC power supply that supplies the power to the commercial load is operating or during a power failure, and the harmonic current generated in the commercial load can be supplied to the AC power supply side. Can be suppressed. 7 and 9
Comparing the input conversion units AD of No. 2 with each other, the configuration is different only in the presence or absence of the current transformer 3 and the transformer PT _IN . Therefore, if the current transformer 3 is added to FIG. 9 and the control device is arranged accordingly, the input conversion unit AD of the UPS can be utilized as an active filter. Further, comparing the input conversion unit AD and the output conversion unit (inverter) DA with respect to the circuit configuration of FIG. 9, the configuration is different only in the presence or absence of the filter capacitor C _AC (the existence of the transformer T is not essential. Absent). The control device is an AD for the input conversion unit.
C is for controlling the current, whereas the DAC for the inverter is for controlling the voltage. Therefore, the input conversion unit AD can be used as an inverter by inserting a filter capacitor C _IN into the input conversion unit and adding a voltage control function to the control device. If the energy converter provided in the UPS is sufficiently large, for example, if an energy source such as a fuel cell is provided in place of the battery B, power is supplied from the AC power source during the period of power failure by the AC power source 1. It is possible to supply power to the load that it was receiving from UPS for a long time through the input system. If the UPS energy source is a solar cell, this energy is converted and supplied to the conversion load while the energy from the solar cell is sufficiently obtained during the daytime, and the power is supplied to the AC power supply (commercial power system) side. UPS, at night, while there is no energy from solar cells
Can also reconvert the power received from the commercial power system and supply it to the conversion load.

[0012]

Next, an embodiment of the present invention will be described. FIG.
Shows the UPS (block shown by the alternate long and short dash line) of the first embodiment. Reference numeral 1 is an AC power source, 2 is a commercial load, 3 is a current transformer, and AD is an input converter, which is composed of a bidirectional converter. L _IN is a reactor, PT _IN is a transformer, S _{1 to} S ₄ are switches, ADC is an input converter controller, B is a battery, DA is an inverter, and S _{5 to} S _{8 are.}
Is a switch, L _AC and C _AC are filters, T is a transformer, 4AC is a conversion load, DAC is a controller of the inverter DA, and PT _OUT is a transformer. Reference numeral 10 represents an AC power supply switch. UPS is the original purpose of conversion load 4
While supplying power to AC uninterruptively, it operates as an active filter of the commercial load 2 while the AC power supply 1 is supplying power to suppress the harmonic current flowing in the AC power supply 1, that is, the harmonic current generated in the commercial load 2 is UPS. When the power is cut off, the switch 10 is opened to disconnect the AC power supply, and the bidirectional converter is operated as an inverter to the commercial load 2 to supply AC power at a constant voltage. U in FIG.
In PS, a filter capacitor C _IN is added to the input side so as to have the same configuration as the conventional UPS in FIG. Also,
A current transformer 3 for sensing the current flowing through the commercial load 2 is provided. A battery will be described as an example of the energy converter, but the energy converter is not limited to the battery and may be a DC power source. For example, a solar cell, a fuel cell, or the like, which is an energy converter, is preferable because it can supply power for a long time. FIG. 2 is a configuration example of a control device ADC that selectively uses current control and voltage control. (IC) part is for current control,
The (VC) part is a part for voltage control. In addition, FIG.
(E) shows the waveform of each part until the current control reference signal is produced. Electronic switch DS is AC power supply 1
The signal on the IC side is passed during the power feeding of, and the signal on the VC side is passed during the power failure.

Among the functions of UPS, the function as an active filter will be described first. The waveform of the current supplied from the AC power source 1 to the commercial load 2 is generally distorted and is not a sine wave. In particular, when the commercial load 2 is a rectifier, the current waveform has a pulse shape and contains many harmonic current components. The signal obtained by sensing the commercial load current by the current transformer 3 is SG _X. Bandpass signal SG _X
The fundamental wave component SG _O is taken out by applying the filter BPF. S
By removing SG _O from G _X, the signal SG _H of the harmonic component in the current flowing through the commercial load 2 can be taken out. Further, since it is necessary to control the DC voltage E _C to be constant in order to charge the battery B, the E _C is fed back and inputted to the reference DC voltage E _REF and the error amplifier A _E , and the difference is dealt with. Output signal E _R is obtained. Next, change the voltage on the input side to PT _IN
The voltage SG _E sensed in step S3 is used as a sine wave reference signal, SG _E (for example, 1 × sin ωt) and E _R are input to the multiplier M, and the amplitude of the sine wave signal SG E is proportional to E _R.
F (E _R × sin ωt) is obtained. High frequency signal SG _H
And the sum of the fundamental wave signal SG _F that charges the battery B and feeds to the inverter DA, SC _I (= SG _H + SG _F )
Is a reference signal for current control of the input converter AD. Feeding back the current signal SG _I of the current transformer 4, which was inputted to the error amplifier A _I together with the reference signal SC _I, to obtain the output signal S _I corresponding to the difference, the S _I and the high frequency of the triangular wave voltage signal S _T enter the door to the comparator COM _I, sell the pulse width control signal PWM _I. The pattern of PWM _I becomes the level of E during the period of S _I > S _T when S _I is positive, and becomes the level of zero during the period of otherwise. Also S
_I is zero -E, in other periods during the S _I <S _T when is negative. The signal PWM _I is input to the pulse distributor D through the electronic switch DS. In the pulse distributor D, a positive pulse train and a negative pulse train of PWM _I are separated on the basis of the signal PWM _I, and these are supplied to the power amplifiers P _{1 to} P ₄ through a photocoupler that can be galvanically isolated, and the transistor Q ₁ outputs a signal to turn on and off the to Q _4. Signal S that senses the output current of input converter AD
If by feeding back the G _I is SG _I follow controlled to be the reference signal SC _I, current flowing out of the input conversion unit AD receives the harmonic current flowing in the commercial load 2, itself is powered from the AC power supply 1 Basic It is the sum of wave currents. Therefore,
The current flowing from the AC power supply is the fundamental current flowing in the commercial load 2 and the fundamental current flowing in the input conversion unit AD, and does not include the harmonic current component. If the commercial load 2 is no load, the signal SG _X becomes zero, and the input conversion unit AD of the UPS has a control function to make the input current required by itself be sinusoidal.

If the sign of the signal SG _F of the fundamental wave is made negative, the current control signal SC _I = SG _H −SG _{F is obtained} , and the input current of the input converter AD itself becomes a negative sine wave current. This indicates that there is an output from the input conversion unit AD. That is, the input converter AD is not only the harmonic current of the commercial load 2,
The fundamental wave current component will also be output. If an energy converter such as a solar cell or a fuel cell is used as the battery B, the input conversion unit AD can be used as an inverter this time to output AC power. This output is supplied to a commercial load, and if there is a surplus power, it can be sent to a commercial power system (shown as an AC power supply in FIG. 1) side to supply power to other general loads on the system side.

The input converter AD is used as a constant voltage inverter during the period when the AC power supply 1 is out of power. In this case, the switch 10 is opened to disconnect the AC power supply 1. Next, this will be described. The inverter (conversion from direct current to alternating current) is constituted by the bridge circuit composed of the semiconductor switches S _{1 to} S ₄ and the alternating current filters L _IN and C _IN at the alternating current terminals X _and Y, and the output of the battery B on the direct current side. Is converted into alternating current to supply power to the commercial load side on the input side.

Next, voltage control when the input conversion unit AD is used as an inverter will be described. In the configuration of FIG. 2, a reference signal for voltage control is created in the portion (VC). By feeding back the signal SG _E which senses the output voltage in PT _IN, put a sine wave voltage signal V _REF of this and the reference to the error amplifier A _V, sell output signal V _R corresponding to these inputs. The error response signal V _R and the triangular wave signal S _T are compared with each other by the comparator CO
Put it in M _V to get its output signal PWM _V. Pattern of PWM _V is, E in the period V _R> S _T when the positive V _R
Level becomes zero level in the other period. The -E during the V _R <S _T when a negative V _R, becomes zero in other periods. Signal PWM _V to electronic switch D
Input to the pulse distributor D through S. Pulse distributor D
Then, based on the signal PWM _V , it is separated into a positive pulse train and a negative pulse train of PWM _V , and this is given to the power amplifiers P _{1 to} P ₄ through a photocoupler that can be galvanically isolated.
A signal for turning on / off the transistors Q _{1 to} Q ₄ is output.

Next, the control device DAC for generating a signal for controlling the inverter DA of FIG. 1 will be described. FIG. 4 is a block diagram of the control device DAC, and FIGS. 5A to 5E show the relationship of signals in each block. The signal V _REF is a sine wave reference signal that determines the level and frequency of the output voltage of the inverter DA. A is an error amplifier, V _REF and inverter D
The signal SG _OUT corresponding to the output voltage of A is compared and the signal V _R corresponding to the difference between them is output. ST is a high frequency triangular waveform voltage signal. This frequency determines the switching frequency of the switch S ₅ ~S ₈ of the inverter DA. C
OM issues an signal during a period in which the absolute value of V _R by comparing the signal V _R and ST comparator exceeds the absolute value of the ST,
In other periods, the pulse width control becomes zero level (hereinafter P
Signal). D is a pulse distributor. P ₅ to P ₈ produces a control signal to be supplied to each amplifying a signal from the distributor D transistor Q ₅ to Q _8.
A photocoupler for transmitting an optical signal is used to electrically insulate P _{5 to} P ₈ and the distributor D from each other. The positive pulse of PWM is amplified and given to the transistors Q ₅ and Q ₈ to turn it on. In addition, the negative pulse of PWM is amplified and the transistor Q
Give it to ₆ and Q ₇ to turn it on. When the level of the signal SG _OUT decreases, a control signal for increasing the level is output to the transistors Q _{5 to} Q _{8, and} when the level of the signal SG _OUT increases, a control signal for decreasing the level is output, that is, feedback control is performed. Keeps the output voltage of.

FIG. 6 shows a second embodiment of the uninterruptible power supply device of the present invention. When a DC output conversion circuit DD (DC-DC converter) is combined in place of the inverter DA in the embodiment of FIG. 1, a DC voltage output device, a so-called rectifying device, is obtained. The AC power is received, the DC power obtained by the input converter AD is reconverted by DD, and the DC power is supplied to the conversion load 4DC. From the viewpoint of the load 4DC, it can be said that the power supply is a rectifier. The primary winding of the transformer T is connected to the AC terminals X and Y of the bridge circuit composed of the switches S _{5 to} S ₈ , and the output voltage of the secondary winding is rectified by the bridge rectifier circuit Q _REC and further smoothed. A DC voltage with a small ripple voltage is obtained through the filters L _DC and C _DC . This is DC conversion load 4D
Power C Incidentally, if Takamere the conversion frequency of the switch S ₅ to S ₈ frequency, for example more than 20 kHz, the transformer T, a smoothing filter L _DC, to can be greatly miniaturized C _DC, also it is possible to eliminate the noise . Controller DDC generates an on-off signal of the transistor Q ₅ to Q ₈ to the DC voltage of the output constant. In the above-described embodiments, both the input conversion unit and the output conversion unit have been described using the single-phase circuit, but the three-phase circuit can be handled in the same manner as commonly used. Further, although the description has been given by taking the bipolar transistor as an example of the semiconductor switch, other power MOS / FET, IGBT (Insulated Gate B
Devices such as ipolar Transistor) can be used in the same way.

[0019]

INDUSTRIAL APPLICABILITY The present invention makes full use of the functions of a conventional power supply device that receives commercial AC power and outputs uninterruptible AC or DC power, while the present invention newly introduces input to the uninterruptible power supply device. The converter provided in the section is made to function as a bidirectional converter so that it functions as an active filter and an inverter in addition to the converter (rectifier) function of the conventional device.
The installation of the three devices is realized only by the uninterruptible power supply, and the economical and space-saving effects are extremely large as described below. One is that it is possible to economically proceed with harmonic pollution control. 1995/10
In order to comply with the guidelines issued by the Ministry of International Trade and Industry regarding the suppression of harmonic current outflow to commercial power systems, an additional active filter must be installed. As a substitute for the corresponding measure of installing an independent active filter, as shown by the present invention, the measure of adding the function of an active filter to another uninterruptible power supply is taken, and its economical effect is outstanding. That is, the active filter is not a so-called power supply device having a power feeding function but a device used only for suppressing harmonic current pollution. In the case of a device with such a strong wearing property and a high cost, the priority of capital investment tends to be low upon introduction, and the introduction does not proceed. We cannot take measures to control pollution. If the function of the active filter is added to the uninterruptible power supply device having a high priority of installation from the request from the load side as in the present invention, the cost burden will be lightened and the pollution control effect can be obtained. The second is to use the function of the uninterruptible power supply to 100% or more. This is obtained by operating the bidirectional converter in the input section as an inverter during a power failure. Further, nearly 100% of the electric power supplied to the computer, which is the conversion load of the present invention, is converted into thermal energy and dissipated in the computer room, raising the room temperature. On the other hand, it is a necessary condition for the computer to maintain the temperature of the operating environment near 20 ° C. Therefore, the air conditioner is indispensable in the computer room. However, this air conditioner is currently operated directly from a commercial power source from the economical point of view. Therefore, if there is a power outage, the air conditioning equipment will stop and the temperature of the computer room will rise,
Although power can be supplied to the computer from a general UPS, the operation of the computer must be stopped. That is, in the conventional computer system, there is no choice but to stop the UPS while leaving a spare capacity. 1
00% is not used up. When the uninterruptible power supply of the present invention is applied to these computer systems, in the event of a power failure of the AC power supply, the input bidirectional converter is used as an inverter to control the air conditioning equipment (the restart is easy even if the power supply is momentarily cut off. The power can be supplied to the computer and the room temperature can be controlled while the power supply to the computer is continued from the inverter of the present invention. Run the computer as much as possible to discharge the battery.
Using the bidirectional converter as an inverter only causes a slight increase in cost in relation to the control device, and a power supply system can be constructed much more economically than installing a separate power supply for air conditioning equipment separately. The effect of the present invention is extremely remarkable as long as the battery can supply power for a long time instead of the lead acid battery (for example, a fuel cell or a solar cell). Further, a DC conversion load requiring 48 V DC, such as an electronic exchange of a telephone, is supplied with power from the DC-DC converter of the uninterruptible power supply unit of the present application, and both are connected to the air conditioning facility (commercial load) at the time of power failure. By operating the directional converter as an inverter and supplying power, the temperature rise in the exchange room can be suppressed and the telephone exchange service can be continued even during a power outage of the commercial AC power supply. Further, in comparison with installing three devices of an uninterruptible power supply, an active filter and an inverter, respectively, in the case where the functions of the active filter and the inverter are added to the uninterruptible power supply as in the present invention, the constituent parts Since the number is greatly reduced, the probability of failure occurrence is reduced and reliability is increased. Furthermore, the space required for installing the device is small, and the installation place can be easily secured. And the like.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of an uninterruptible power supply device of the present invention.

FIG. 2 shows an example of a control device of an input conversion unit.

3A to 3E for explaining FIG. 2 show waveforms of respective parts.

FIG. 4 shows an example of a control device of an output conversion unit.

5 (a) to 5 (e) for explaining FIG. 4 show waveforms of respective parts.

FIG. 6 shows a second embodiment of the present invention.

FIG. 7 shows a configuration example of a conventional active filter.

8A to 8C show waveforms at various parts for explaining FIG. 7.

FIG. 9 shows a conventional uninterruptible power supply.

[Explanation of symbols]

1 AC power supply 2 Commercial load 3 Current transformer 4 Current transformer 10 Switch S _{1 to} S ₄ Semiconductor switch D _{1 to} D ₄ Diode AD input converter B Battery DA AC converter (inverter) ADC controller DAC controller DD output converter circuit PT _IN transformer T output transformer L _AC reactor C _AC capacitor PT _OUT output voltage transformer BPF band pass filter 4 AC conversion load DAC conversion device DS electronic switch P _{1 to} P ₄ power amplifier SG _I input current signal SG _X current flowing to commercial load signal is E by sensing a current transformer SG _O fundamental component SG _H harmonic component of the signal _{a, a V, a I,} a E error amplifier M multiplier COM _V comparator COM comparator D pulse distributor E _C DC voltage out of the DC voltage E _R the error amplifier E _REF reference Current signal from the reference signal of the current control signal SC _I input conversion unit AD of the voltage of the signal SG _E input from the transformer PT _IN signal SG _F multiplier is E and sensed by M SG _I current transformer 4 S _I signal from the error amplifier a signal of the output signal PWM pulse width control of the output signal S _T triangular wave voltage signal PWM _I pulse width control signal V _REF reference signal V _R output signal PWM _V comparator than _I SG _OUT PT _OUT

Claims (2)

(57) [Claims] 1. A power supply device that is connected in parallel with a commercial load and receives power from an AC power supply via a common switch, the power supply device converting AC power into DC power and also converting DC power into DC power. Equipped with a bidirectional converter that can also be converted to AC power, a battery connected to the DC output of this bidirectional converter, and an inverter that also operates by connecting its input side to the DC output of the bidirectional converter and the battery. The AC input side of the bidirectional converter is connected to the AC power supply and the commercial load, the inverter supplies the AC power converted by itself to the AC conversion load, and the switch is closed when the AC power supply can supply power. , Used in an open state during a power failure, and the control device for controlling the power conversion function of the bidirectional converter generates two control signals, The first control signal is generated while the AC power is being supplied, and senses the AC input current and DC output voltage of the bidirectional converter itself and the current flowing in the commercial load, respectively, and performs the control. A signal is input to the device, the DC output voltage is controlled to a predetermined voltage level, the waveform of the AC input current for obtaining the DC output voltage is shaped into a sine wave, and flows into the commercial load. A second control signal is a control signal for causing only a harmonic current component of the current to flow into the bidirectional converter, and the second control signal is generated during a period in which the AC power supply is out of power. A control signal for sensing an AC voltage output to the AC side of the converter, and converting the DC power of the battery into an AC voltage of a desired constant frequency constant voltage, Motor control devices, uninterruptible power supply and outputs a control signal to the AC voltage of the desired constant frequency constant voltage conversion load sensing the AC output voltage of the inverter. 2. A power supply device that is connected in parallel with a commercial load and receives power from an AC power supply through a common switch, the power supply device converting AC power into DC power and converting DC power into DC power. A bidirectional converter that can also be converted to AC power, a battery connected to the DC output of this bidirectional converter, and a DC that operates by connecting the input side to the DC output of the bidirectional converter and the battery.
A DC converter, an AC input side of the bidirectional converter is connected to the AC power source and a commercial load, the DC-DC converter supplies DC power converted by itself to a DC conversion load, and the switch is The control device for controlling the power conversion function of the bidirectional converter generates two control signals, which are used when the AC power supply is closed when power can be supplied and is opened during power failure, and the first control signal is AC. It is generated during the period in which the power source is supplying power, and senses its own AC input current and DC output voltage of the bidirectional converter and the current flowing in the commercial load, respectively, and inputs a signal to the control device, The output voltage is controlled to a predetermined voltage level, and the waveform of the AC input current for obtaining the DC output voltage is shaped into a sine wave. Of the current flowing in the commercial load, a control signal for outputting only a harmonic current component into the bidirectional converter is output, and the second control signal is a period during which the AC power source is out of power. The DC-DC is a control signal that is generated by the DC-DC converter and senses the AC voltage output to the AC side of the bidirectional converter to convert the DC power of the battery into a desired constant-frequency constant-voltage AC voltage. An uninterruptible power supply device, wherein a control device of the converter senses a DC output voltage of the DC-DC converter and outputs a control signal to make a DC constant voltage desired by the conversion load.