JP2004320983A - Uninterruptible power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the reduction of output voltage due to an operation delay of a relay for separating an AC power supply side from an uninterrruptible power supply, and to prevent a current from flowing between the AC power supply side and the uninterrruptible power supply side unintentionally. <P>SOLUTION: When the AC power supply 1 is short-circuited, a parallel converter 2, which is connected in parallel to the AC power supply 1 via input terminals 11, is operated so that its output voltage becomes "0", and a series inverter 3, which is connected in series between an input relay 7 and an output terminal 12, is operated for compensation using a smoothing capacitor 4 as a power supply so that an applied voltage between output terminals 12 becomes an output voltage command value Vout *. Hereby, since the output voltage of the parallel converter 2 is "0", which causes no potential difference between the AC power supply 1 and the output of the parallel converter 2, a current does not flow between the AC power supply 1 and the output of the parallel converter 2, and the applied voltage between the output terminals 12 is continuously kept to be the output voltage command value Vout * owing to the series inverter 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention provides an uninterruptible power supply device that supplies power to a load while stabilizing an AC power supply voltage, and that supplies power to a load using energy stored in energy storage means when the AC power supply fails. In particular, the present invention relates to an uninterruptible power supply device that prevents a decrease in supply power when switching from a normal operation to a power outage operation.

Conventionally, many uninterruptible power supplies of this type have been proposed, and for example, those configured as shown in FIG. 3 are known.

FIG. 3 shows an example of a single-phase circuit. As shown in FIG.
An input relay 7 is interposed between an input terminal 11 to which the load 6 is connected and an output terminal 12 to which the load 6 is connected.
When an abnormality occurs, the AC power supply 1 is disconnected from the uninterruptible power supply. In the figure, reference numeral 2 denotes a parallel converter connected in parallel to the input terminal 11 via the input relay 7 and capable of performing a rectifier operation and an inverter operation. Also,
In the figure, reference numeral 3 denotes a series inverter which is connected in series between the input relay 7 and the output terminal 12 and performs an inverter operation. An energy storage means 5 such as a smoothing capacitor 4 and a battery is connected between the parallel converter 2 and the series inverter 3 in parallel with these.

The parallel converter 2 and the series inverter 3 are controlled by a control circuit 10. The control circuit 10 detects the AC power supply voltage Vin supplied from the AC power supply 1 detected by the voltage detector 8 and the AC power supply voltage Vin detected by the voltage detector 9. Control is performed based on the terminal voltage Vc of the smoothing capacitor 4 so that the output voltage to the load 6 becomes a specified voltage.

The parallel converter 2 and the series inverter 3 are, for example, as shown in FIG. 4, configured by a full bridge circuit using a semiconductor switch such as a known transistor. Is performed based on the pulse signal PWM1 output from the control circuit 10, and the series inverter 3 is performed based on the pulse signal PWM2. In addition, on the output side of the parallel converter 2 or the series inverter 3, a filter including a reactor L and a capacitor C may be arranged as shown in FIG.

In the uninterruptible power supply 100 configured as described above, when the AC power supply voltage Vin of the AC power supply 1 detected by the voltage detector 8 is within an allowable range, the input relay 7 is turned on, and the parallel converter 2 is charged and discharged based on the terminal voltage Vc of the smoothing capacitor 4 detected by the voltage detector 9 so that the voltage becomes a specified voltage, thereby converting the AC power of the AC power supply 1 into DC power. The terminal voltage Vc is maintained at a specified voltage.

At this time, the series inverter 3 converts the DC power of the smoothing capacitor 4 into AC power so that the voltage applied to the load 6 becomes a specified voltage, and compensates for the excess or deficiency of the AC power supply 1. By outputting ΔV, the voltage applied to the load 6 is maintained at a specified voltage.

On the other hand, if the AC power supply voltage Vin from the AC power supply 1 is out of the allowable range and it is determined that an abnormality has occurred on the AC power supply 1 side, the input relay 7 is switched to the cutoff state,
The operation of the serial inverter 3 is stopped, the parallel converter 2 is operated as an inverter, and the DC power of the energy storage means 5 is converted into specified AC power and supplied to the load 6 to disconnect the AC power supply 1. Load 6
The voltage applied to the device is maintained at a specified voltage (for example, Patent Document 1).
JP 2002-199620 A

However, in the above-described conventional uninterruptible power supply, when the input relay 7 is configured by a mechanical contact, it takes several milliseconds until the input relay 7 receives an on / off command and actually operates. An operation delay of about 10 ms occurs.

For this reason, from the occurrence of a power failure, the input relay 7 is controlled and the input relay 7 is controlled to be in a cut-off state until the AC power supply 1 is disconnected from the uninterruptible power supply device 100. Causes a power supply voltage after a power failure. In this state, when the power failure is detected, the operation of the serial inverter 3 is stopped, and the parallel converter 2 is operated as an inverter to continue supplying power to the load. Since the AC power supply 1 is connected in parallel with the voltage, for example, when the AC power supply voltage Vin is out of an allowable range due to a short circuit occurring on the AC power supply 1 side, the AC power supply 1 side is in a short-circuit state. Therefore, the parallel converter 2 is also short-circuited, and there is a problem that the voltage applied to the load 6 cannot be maintained at the specified voltage.

In addition, when the parallel converter 2 operates to maintain the specified voltage, a potential difference between the power supply voltage after the power failure and the output voltage of the parallel converter 2 occurs. May flow. In particular, in the case of a short-circuit power failure caused by the short-circuit of the AC power supply 1, an unintended short-circuit current flows, and in some cases, the entire uninterruptible power supply may be affected.

In addition, when the AC power supply 1 is opened due to a power failure, the AC power supply 1 supplies a voltage from the uninterruptible power supply 100 even though the AC power supply 1 is originally in a non-power supply state. There is also.

Therefore, the present invention has been made in view of the above-mentioned conventional unsolved problem, and it is possible to avoid a decrease in output voltage when disconnecting the AC power supply side with a decrease in AC power supply voltage. It is intended to provide an uninterruptible power supply.

In order to achieve the above object, the uninterruptible power supply according to claim 1 of the present invention includes an AC power supply side inserted between an input terminal to which AC power is supplied and an output terminal connectable to a load. Cut-off means for disconnecting, a parallel power conversion means connected in parallel with the input terminal between the cut-off means and the output end, and between a parallel connection point of the parallel power conversion means and the output end. A serial power conversion unit interposed in series, and a power storage unit that allows power to be interchanged between the parallel power conversion unit and the serial power conversion unit. The power conversion means performs an operation of compensating the supplied AC power using the power storage means as a power supply so that the AC output of the output terminal becomes an output specified value, and the parallel power conversion means performs a power storage operation of the power storage means. Charge and discharge to the specified value In the uninterruptible power supply device, the power failure detection means for detecting a power failure is provided, and when the power failure is detected by the power failure detection means, the AC power supply side is cut off by the interruption means, and the serial power conversion is performed. The means is operated by using the power storage means as a power supply so as to output the full voltage of the output terminal so that the AC output of the output terminal becomes the output specified value.

According to the first aspect of the present invention, when the supplied AC power is sound, the series power conversion means compensates the supplied AC power so that the AC output at the output terminal becomes a specified output value. As described above, the power storage unit operates using the power storage unit as a power supply. The parallel power conversion means performs charging and discharging so that the amount of power stored in the power storage means becomes a specified value. Therefore, when the supplied AC power is sound, the AC output at the output terminal is maintained at the specified output value.

On the other hand, if the AC power supply side detects, for example, a short-circuit power failure and the power failure detection means detects the short-circuit power failure, the AC power supply side is disconnected from the uninterruptible power supply by the interruption means.
Here, from the occurrence of the short circuit on the AC power supply side to the time when the cutoff means operates in response to the short circuit and the disconnection of the AC power supply side is completed, the parallel power conversion means is also in a short circuit state. However, the serial power converter operates to output the full voltage of the AC output of the uninterruptible power supply so that the AC output at the output terminal becomes the output specified value when the short circuit is detected. Even if an operation delay occurs until the disconnection of the supply side is completed, the AC output at the output terminal is maintained at a specified value.

Further, the uninterruptible power supply according to claim 2 is a disconnecting means for disconnecting the AC power supply side interposed between an input terminal to which AC power is supplied and an output terminal connectable to a load; A parallel power conversion means connected in parallel with the input terminal between the output terminal and a means, and a series power conversion device inserted in series between a parallel connection point of the parallel power conversion means and the output terminal. Means, and a power storage means for enabling power interchange between the parallel power conversion means and the serial power conversion means.When the AC power is sound, the series power conversion means An operation of compensating the supplied AC power is performed using the power storage means as a power source so that an output becomes a specified output value, and the parallel power conversion means performs charging and discharging so that the stored amount of the power storage means becomes a specified value. Uninterruptible power supply A power failure detection means for detecting a power failure, and an AC voltage detection means for detecting the supplied AC power voltage, and when the power failure detection means detects a power failure, And the parallel power conversion means is operated such that the parallel connection point side becomes an AC power supply voltage detected by the AC voltage detection means, and the series power conversion means is connected to the AC output of the output terminal. Is operated using the power storage means as a power supply so as to compensate the output voltage of the parallel power conversion means so that the output specified value is obtained.

According to the second aspect of the present invention, when the supplied AC power is sound, the series power conversion means compensates the supplied AC power so that the AC output at the output terminal becomes the specified output value. As described above, the power storage unit operates using the power storage unit as a power supply. The parallel power conversion means performs charging and discharging so that the amount of power stored in the power storage means becomes a specified value. Therefore, when the supplied AC power is sound, the AC output at the output terminal is maintained at the specified output value.

On the other hand, if the AC power supply side fails and the power failure detection means detects this,
The AC power supply side is separated from the uninterruptible power supply by the interruption means. Here, from the occurrence of a power failure on the AC power supply side to the time when the shutoff means operates in response to this and the disconnection of the AC power supply side is completed, the output end of the cutoff means is supplied with AC power. Residual voltage will be generated.

However, when a power failure is detected, the parallel power conversion means operates such that the parallel connection point side becomes the supplied AC power voltage detected by the AC voltage detection means, and the AC power supply side and the parallel connection point Since there is no potential difference between the power supply and the power supply, no unintended current flows due to a power failure. On the other hand, the serial power conversion means performs an operation of compensating for the AC output of the parallel power conversion means so that the AC output at the output terminal becomes a specified output value when the power failure is detected.

Therefore, even if an operation delay occurs until the disconnection of the AC power supply side is completed, the AC output at the output terminal is maintained at the specified value, and an unintended current does not flow through the uninterruptible power supply.

As described above, according to the uninterruptible power supply according to claim 1 of the present invention, when the AC power supply side is short-circuited, for example, when the power supply is short-circuited, the AC power supply side is separated from the uninterruptible power supply side by the cutoff unit. At the same time, the parallel power conversion means is operated so that the parallel connection point side has a preset short-circuit level, and the series power conversion means is operated such that the AC output at the output terminal has the specified output value. Therefore, even if an operation delay occurs until the disconnection of the AC power supply side is completed, the AC output at the output terminal can be maintained at the specified value.

Further, according to the uninterruptible power supply according to claim 2, when a power failure is detected, the AC power supply side is cut off by the interruption means, and the parallel power conversion means is connected to the parallel connection point when the power failure is detected. Operate so that the supplied AC power voltage is detected by the voltage detection means, and compensate the AC output of the parallel power conversion means so that the AC output at the output terminal becomes the specified output value. Even if an operation delay occurs until the disconnection of the AC power supply side is completed, the AC output at the output terminal can be maintained at the specified value, and the uninterruptible power supply It is possible to prevent an unintended current from flowing.

  Hereinafter, an embodiment of the present invention will be described.

First, a first embodiment will be described. The configuration of the uninterruptible power supply 100 is as follows.
The configuration of the conventional uninterruptible power supply device 100 shown in FIG. 3 is the same except that the control circuit 20 is applied instead of the control circuit 10, and therefore, the same portions are denoted by the same reference numerals, and detailed descriptions thereof are given. Description is omitted.

  FIG. 1 shows the configuration of the control circuit 20.

As shown in FIG. 1, the control circuit 20 includes a parallel converter control unit 30 for controlling the parallel converter 2, a series inverter control unit 40 for controlling the series inverter 3, and a voltage abnormality detection unit 50. It is composed of

The parallel converter control unit 30 includes a DC voltage adjustment unit 31 that performs an adjustment operation so that the terminal voltage Vc of the smoothing capacitor 4 detected by the voltage detector 9 matches a predetermined value Vc *. A subtractor 32 for subtracting the adjustment voltage amount calculated by the DC voltage adjustment unit 31 from the AC power supply voltage Vin detected by the detector 8;
And a changeover switch 33 for selecting one of the subtraction value calculated in the above step and the specified value “0” and using the selected value as the output voltage command value Vrect * of the parallel converter 2, and the parallel converter output voltage set by the changeover switch 33. A PWM pulse generator 34 that performs a PWM control based on the command value Vrect * and generates a pulse signal PWM1 for turning on and off a semiconductor switch included in the parallel converter 2.

On the other hand, the series inverter control unit 40 includes an output voltage command generation unit 41 that sets an output voltage command value Vout * of the uninterruptible power supply 100 according to the AC voltage to be applied to the load 6, and an output voltage command generation unit 41. A subtractor 42 for subtracting the AC power supply voltage Vin detected by the voltage detector 8 from the output voltage command value Vout * set in the above step, and a subtraction value calculated by the subtractor 42 and an output voltage set by the output voltage command generator 41. A switch 43 for selecting any one of the command values Vout * as the compensation voltage command value Vocmp *, and performing PWM control based on the compensation voltage command value Vocmp * selected by the switch 43 to form the series inverter 3 And a PWM pulse generator 44 for generating a pulse signal PWM2 for turning on and off the semiconductor switch.

Further, the voltage abnormality detection unit 50 detects the AC power supply voltage V detected by the voltage detector 8.
is determined to be within a preset allowable range in which the AC power supply voltage Vin can be considered to be normal, and when it is determined to be within the allowable range, the input relay 7 is controlled to a conductive state. At the same time, the switch 33 of the parallel converter controller 30 is controlled to select the output of the subtractor 32, and the switch 43 of the serial inverter controller 40 is controlled to select the output of the subtractor 42.

On the other hand, when it is determined that the AC power supply voltage Vin is not within the allowable range, the input relay 7 is controlled to be in the cutoff state, and the changeover switch 33 of the parallel converter control unit 30 is controlled to select the specified value “0”. , And the series inverter control unit 40
Switch 43 is set to the output voltage command value Vout from the output voltage command generator 41.
Switch to selecting *.

  Next, the operation of the first embodiment will be described.

Now, when the AC power supply voltage Vin is within the allowable range, the voltage abnormality detection unit 50 controls the input relay 7 to be in the conductive state and subtracts the change by the changeover switch 33 because the AC power supply voltage Vin is within the allowable range. The output of the subtractor 42 is controlled by selecting the output of the subtractor 32 and the switch 43.

As a result, in the parallel converter control unit 30, the adjustment calculation result for matching the terminal voltage Vc of the smoothing capacitor 4 calculated by the DC voltage adjustment unit 31 to the specified value Vc * is subtracted from the AC power supply voltage Vin. It is set as the output voltage command value Vrect * of the parallel converter 2, and based on this, the pulse signal PWM1 is generated.

On the other hand, in the series inverter control unit 40, a value obtained by subtracting the AC power supply voltage Vin from the output voltage command value Vout * set by the output voltage command generation unit 41 is set as the compensation voltage command value Vocmp *. , A pulse signal PWM2 is generated.

Therefore, by operating parallel inverter 2 such that terminal voltage Vc of smoothing capacitor 4 matches its specified value Vc *, terminal voltage Vc of smoothing capacitor 4 is maintained at its specified value Vc *. The series inverter 3 operates to output the compensation voltage command value Vocmp *, thereby correcting the AC power supply voltage Vin. As a result, a voltage equivalent to the output voltage command value Vout * is applied to the output terminal 12. As a result, the voltage applied to the load 6 is maintained at the output voltage command value Vout *.

In this state, when the AC power supply voltage Vin decreases due to a short-circuit power failure occurring on the AC power supply 1 side, the voltage abnormality detection unit 50 detects this when the AC power supply voltage Vin is out of an allowable range, and The relay 7 is switched to the cutoff state, and the changeover switch 33 is controlled to select the specified value “0”.
At 3, control is performed to select the output voltage command value Vout *.

Thereby, the parallel converter control unit 30 operates the parallel converter 2 so that the output voltage thereof becomes the specified value “0”. In addition, the series inverter control unit 4
At 0, the series inverter 3 is operated as an inverter so that its output voltage becomes the output voltage command value Vout *, that is, the DC power of the energy storage means 5 is converted to AC power and applied to the output terminal 12. Therefore, the output voltage command value Vout * is continuously applied to the load 6.

Here, when a decrease in the AC power supply voltage Vin is detected, the input relay 7 is controlled to be in a cut-off state. However, when the input relay 7 is configured by a mechanical contact, the AC power supply 1 side is connected to the uninterruptible power supply 100. There is an operation delay before being disconnected from the side. In a state where the operation of the input relay 7 is not completed, since a short circuit has occurred in this case, the parallel converter 2 is also in a short circuit state. However, here,
The output voltage of the parallel converter 2 becomes “0”, that is, the parallel converter 2
Since the input relay 7 is operated so that the side connected to the load 6 side becomes "0", no potential difference occurs between the AC power supply 1 side and the output side of the parallel converter 2. Therefore, an unintended short-circuit current does not flow between the parallel converter 2 and the AC power supply 1, which adversely affects the uninterruptible power supply itself or equipment connected to the same system. Can be avoided, and the reliability can be improved.

  Next, a second embodiment of the present invention will be described.

The second embodiment is the same as the first embodiment except that the configuration of the control circuit 20 is partially different. Therefore, the same components are denoted by the same reference numerals, and detailed description thereof is omitted. I do.

  FIG. 2 illustrates a control circuit 20a according to the second embodiment.

As shown in FIG. 2, in the parallel converter control unit 30a, the terminal voltage Vc of the smoothing capacitor 4 detected by the voltage detector 9 matches the specified value Vc *, as in the first embodiment. The adjustment operation is performed by the DC voltage adjustment unit 31 so that the adjustment voltage amount calculated by the DC voltage adjustment unit 31 is subtracted from the AC power supply voltage Vin.

Then, one of the subtraction value calculated by the subtractor 32 and the AC power supply voltage Vin detected by the voltage detector 8 is selected by the changeover switch 33a, and this is set as the output voltage command value Vrect * of the parallel converter 2. Is done. Then, PWM control is performed in the PWM pulse generator 34 based on the output voltage command value Vrect * set by the changeover switch 33a, and a pulse signal PWM1 for turning on and off the semiconductor switch constituting the parallel converter 2 is generated. Generated.

On the other hand, in the series inverter control unit 40a, similarly to the first embodiment, the AC power supply voltage Vin detected by the voltage detector 8 from the output voltage command value Vout * set by the output voltage command generation unit 41. Is subtracted by the subtractor 42. In the second embodiment, the output of the parallel converter 2 selected by the changeover switch 33a of the parallel converter control unit 30a from the output voltage command value Vout * set by the output voltage command generation unit 41 in the subtractor 45. The voltage command value Vrect * is subtracted. Then, one of the subtraction value calculated by the subtractor 42 and the subtraction value calculated by the subtractor 45 is selected by the changeover switch 43a, and this is set as the compensation voltage command value Vocmp *.

Then, PWM control is performed in the PWM pulse generator 44 based on the compensation voltage command value Vocmp *, and a pulse signal PWM2 for turning on and off the semiconductor switch constituting the serial inverter 3 is generated.

When the AC power supply voltage Vin is within the allowable range, the voltage abnormality detection unit 50 controls the input relay 7 to be in a conductive state, and furthermore, switches the output of the subtractor 32 to the output voltage command of the parallel converter 2 by the changeover switch 33a. The value is set as the value Vrect *, and the output of the subtractor 42 is set as the compensation voltage command value Vocmp * by the changeover switch 43a. On the other hand, when the AC power supply voltage Vin is out of the allowable range, the input relay 7 is controlled to be in the cut-off state, and the AC power supply voltage Vin is set as the output voltage command value Vrect * of the parallel converter 2 by the changeover switch 33a. The output of the subtractor 45 is set as the compensation voltage command value Vocmp * by the changeover switch 43a.

  Next, the operation of the second embodiment will be described.

When the AC power supply voltage Vin is within the allowable range, the input relay 7 is controlled to be conductive, the output of the subtractor 32 is selected by the changeover switch 33a, and the output of the subtractor 42 is selected by the changeover switch 43a. Therefore, the uninterruptible power supply 100 operates in the same manner as in the first embodiment.

From this state, when the output of the AC power supply 1 drops for some reason and the AC power supply voltage Vin falls outside the allowable range, the input relay 7 is controlled to be cut off, and the changeover switch 33a converts the AC power supply voltage Vin to the parallel converter voltage. 2 output voltage command value Vrect
*, And the output of the subtractor 45 is set as the compensation voltage command value Vocmp * by the changeover switch 43a. Therefore, in the parallel converter 2, the inverter operation is performed so that the output voltage becomes the AC power supply voltage Vin.

Here, in a state in which the input relay 7 has not yet been cut off due to an operation delay, the residual voltage of the AC power supply voltage Vin appears on the load 6 side of the input relay 7. 2 operates so that its output voltage becomes the residual voltage of the AC power supply voltage Vin.

Therefore, there is no potential difference between the output voltage of the parallel converter 2 and the AC power supply voltage Vin, and the current flowing between the AC power supply 1 and the uninterruptible power supply 100 becomes zero. Therefore, even when the input relay 7 is not actually in the cut-off state, a state equivalent to the case where the AC power supply 1 and the uninterruptible power supply device 100 are separated can be obtained.

In particular, when a short circuit occurs, an unintended short-circuit current flows through the short-circuit portion. However, the parallel converter 2 does not generate a potential difference between the AC power supply voltage Vin and the output voltage of the parallel converter 2. Therefore, it is possible to prevent the uninterruptible power supply device 100 itself or devices connected to the same system from being adversely affected due to an unintended short-circuit current flowing due to a short circuit.

On the other hand, in the series inverter 3, the output of the parallel inverter 2 is calculated based on the output voltage command value Vout *.
The output voltage command value Vrect * is subtracted, that is, the value obtained by subtracting the AC power supply voltage Vin is operated as the compensation voltage command value Vocmp *. That is, the series inverter 3
A compensation operation is performed on the output of the parallel inverter 2 so that the output voltage command value becomes Vout *.

That is, when the AC power supply voltage Vin is within the allowable range, the series inverter 3 performs a compensating operation on the AC power supply voltage Vin so as to maintain the output voltage of the device at the output voltage command value Vout *. Is out of the allowable range, the parallel converter 2 performs a compensation operation to maintain the output voltage of the device at the output voltage command value Vout *.

Therefore, even in the second embodiment, even if an operation delay occurs before the cutoff of the input relay 7 is completed, the output voltage is not reduced and the applied voltage to the load 6 is reduced. It can be maintained at the command value Vout *, and can be realized without being affected by the residual voltage of the AC power supply voltage Vin.

Further, it is possible to prevent an unintended current from being generated due to the AC power supply voltage Vin being out of the allowable range. Since the output voltage command value Vout * is compensated by the output voltages of the parallel converter 2 and the serial converter 3, the operation of the input relay 7 is completed, and the AC power supply 1 is disconnected from the uninterruptible power supply 100. It is not affected at all.

Further, in the second embodiment, the AC power supply voltage Vin is actually detected,
Since the parallel inverter 2 is controlled so as to output a voltage equivalent to the AC power supply voltage Vin, it is possible to accurately prevent an unintended current from flowing.

In the first and second embodiments, the case where the parallel converter 2 or the series inverter 3 is configured by a full bridge circuit including a switching element and a diode connected in anti-parallel to the switching element has been described. However, the present invention is not limited to this. For example, the present invention can be applied to a half-bridge circuit.

In the first and second embodiments, the case where the present invention is applied to a single-phase uninterruptible power supply is described. However, the present invention is not limited to this. Needless to say, the present invention can also be applied to the uninterruptible power supply device.

In each of the above embodiments, the input relay 7 corresponds to the cutoff means, the parallel converter 2 corresponds to the parallel power conversion means, the series inverter 3 corresponds to the series power conversion means, the smoothing capacitor 4 and the energy storage means. Reference numeral 5 corresponds to the power storage means, the voltage detector 8 corresponds to the AC voltage detection means, and the voltage abnormality detection unit 50 corresponds to the short-circuit detection means and the power failure detection means.

FIG. 2 is a schematic configuration diagram illustrating a configuration of a control circuit of the uninterruptible power supply according to the first embodiment. It is a schematic structure figure showing the composition of the control circuit of the uninterruptible power supply in a 2nd embodiment. It is a schematic structure figure showing the composition of an uninterruptible power supply. 4 is an example of a circuit configuration of a parallel converter and a series inverter part of FIG. 3.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Parallel converter 3 Series inverter 4 Smoothing capacitor 5 Energy storage means 6 Load 7 Input relay 8 Voltage detector 9 Voltage detector 10, 20, 20a Control circuit 30, 30a Parallel converter control unit 31 DC voltage adjustment unit 32 Subtraction Switches 33, 33a selector switches 34, 44 PWM pulse controller 40, 40a series inverter controller 41 output voltage command generator 42 subtractors 43, 43a selector switch 50 voltage abnormality detector

Claims (2)

Cut-off means for disconnecting the AC power supply side inserted between an input terminal to which AC power is supplied and an output terminal connectable to a load,
Parallel power conversion means connected in parallel with the input terminal between the cutoff means and the output terminal,
Series power conversion means inserted in series between the parallel connection point of the parallel power conversion means and the output end,
Power storage means that enables the interchange of power between the parallel power conversion means and the serial power conversion means,
When the AC power is sound, the series power conversion unit performs an operation of compensating the supplied AC power using the power storage unit as a power source such that the AC output at the output terminal becomes an output specified value, and performs the parallel power conversion. The conversion unit is an uninterruptible power supply device configured to perform charging and discharging so that the amount of power stored in the power storage unit becomes a specified value.
Having a power failure detection means for detecting a power failure,
When the power failure is detected by the power failure detection means, the AC power supply side is cut off by the interruption means, and the series power conversion means is connected to the output terminal so that the AC output of the output terminal becomes the output specified value. An uninterruptible power supply, wherein the power storage means is operated as a power supply so as to output all voltages. Cut-off means for disconnecting the AC power supply side inserted between an input terminal to which AC power is supplied and an output terminal connectable to a load,
Parallel power conversion means connected in parallel with the input terminal between the cutoff means and the output terminal,
Series power conversion means inserted in series between the parallel connection point of the parallel power conversion means and the output end,
Power storage means that enables the interchange of power between the parallel power conversion means and the serial power conversion means,
When the AC power is sound, the series power conversion unit performs an operation of compensating the supplied AC power using the power storage unit as a power source such that the AC output at the output terminal becomes an output specified value, and performs the parallel power conversion. The conversion unit is an uninterruptible power supply device configured to perform charging and discharging so that the amount of power stored in the power storage unit becomes a specified value.
Power failure detection means for detecting a power failure,
AC voltage detection means for detecting the supplied AC power voltage,
When the power failure is detected by the power failure detection means, the AC power supply side is cut off by the cutoff means, and the parallel power conversion means is configured such that the parallel connection point side becomes the AC power supply voltage detected by the AC voltage detection means. Operating the series power conversion means using the power storage means as a power supply so as to compensate the output voltage of the parallel power conversion means so that the AC output of the output terminal becomes the output specified value. Uninterruptible power supply.

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