JP7080847B2 - Uninterruptible power supply system - Google Patents

Description

The present invention relates to an uninterruptible power supply system.

In an uninterruptible power supply system that requires high reliability, it is necessary to continue supplying power to the load by UPS even if a failure of the uninterruptible power system (UPS) occurs. For this reason, conventionally, a redundant uninterruptible power supply system has been configured by combining a plurality of UPSs.

As such a redundant uninterruptible power supply system, for example, Japanese Patent Application Laid-Open No. 2005-218200 (Patent Document 1) describes a plurality of regular UPS configured to supply power to a constant load and a plurality of regular UPS. Disclosed is an uninterruptible power supply system comprising a spare UPS provided for common backup. Such an uninterruptible power supply system is called a series redundant uninterruptible power supply system or a common standby uninterruptible power supply system.

In a series redundant uninterruptible power supply system, generally, one spare UPS is configured for a plurality of regular UPSs. The output of the spare UPS is input to each of the plurality of regular UPSs as a bypass input power supply. When a maintenance inspection or failure occurs in one regular UPS, the output of the spare UPS becomes the bypass input power supply of the regular UPS, and the load is supplied to the load via the bypass circuit of the regular UPS.

Japanese Unexamined Patent Publication No. 2005-218200

In the above-mentioned series redundant uninterruptible power supply system, the spare UPS is on standby in a no-load operation state while the load is being supplied by a plurality of regular UPSs. Therefore, in the uninterruptible power supply system as a whole, the spare UPS tends to have a lower operating rate than the regular UPS.

Due to such a difference in operating rate between the spare UPS and the regular UPS, an imbalance may occur in the operating rate among a plurality of UPSs constituting the uninterruptible power supply system. Therefore, even if these plurality of UPSs are introduced at the same time, the regular UPSs will deteriorate over time as compared with the spare UPSs. There is concern that the aging deterioration of this regular UPS will affect the reliability of the uninterruptible power supply system.

Therefore, a main object of the present invention is to provide a series redundant uninterruptible power supply system capable of switching between a spare uninterruptible power supply and a regular uninterruptible power supply among a plurality of uninterruptible power supplies.

The uninterruptible power supply system according to the present invention includes a regular uninterruptible power supply and a spare uninterruptible power supply between the first uninterruptible power supply, the second uninterruptible power supply, and the first and second uninterruptible power supplies. It is equipped with a switching device for switching the uninterruptible power supply device. Each of the first and second non-disruptive power supply devices is connected between an AC input terminal connected to an AC power supply, an AC output terminal for supplying AC power to a load, and an AC input terminal and an AC output terminal. A power converter that generates AC power to be supplied to the load, a bypass circuit connected in parallel with the power converter between the bypass input terminal, the bypass input terminal, and the AC output terminal, and the bypass circuit and AC output. Includes a bypass switching circuit that switches between electrical connection and disconnection with terminals. The bypass switching circuit electrically cuts off the bypass circuit and the AC output terminal when power is supplied by the power converter, while electrically disconnects the bypass circuit and the AC output terminal during maintenance or inspection of the uninterruptible power supply or when a failure occurs. It is configured to connect to. The switching device is a first switch electrically connected between the AC output terminal of the first uninterruptible power supply and the load, and the AC output terminal of the first uninterruptible power supply and the second uninterruptible power supply. A fourth switch that is electrically connected between the second and third switches, which are electrically connected in series between the bypass input terminals of the device, and the AC output terminal and load of the second uninterruptible power supply. And the fifth and sixth switches electrically connected in series between the AC output terminal of the second uninterruptible power supply and the bypass input terminal of the first uninterruptible power supply. The node between the second and third switches is electrically connected to the node between the fifth and sixth switches. The switching device connects the 7th switch that selectively connects the bypass input terminal of the 1st uninterruptible power supply to either the AC power supply or the 6th switch, and the bypass input terminal of the 2nd uninterruptible power supply. It further includes a power supply and an eighth switch that selectively connects to any of the third switches.

According to the present invention, it is possible to provide a series redundant uninterruptible power supply system capable of switching between a spare uninterruptible power supply and a regular uninterruptible power supply among a plurality of uninterruptible power supplies.

It is a circuit block diagram which shows the structure of the uninterruptible power supply system which concerns on embodiment of this invention. It is a figure explaining the operation of the uninterruptible power supply system when the failure of the regular UPS occurs. It is a figure explaining the operation of the uninterruptible power supply system when the failure of the regular UPS occurs. It is a circuit block diagram which shows the structure of the uninterruptible power supply system when UPS12 is a spare UPS, and UPS11 and UPS13 are a regular UPS. It is a figure which shows the configuration when the number of UPS is increased to 4 in the uninterruptible power supply system shown in FIG. It is a circuit block diagram which shows the structure of a general series redundancy system. It is a figure explaining the operation of the series redundant system when the failure of the regular UPS occurs.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated.

FIG. 1 is a circuit block diagram showing a configuration of an uninterruptible power supply system 100 according to an embodiment of the present invention.

With reference to FIG. 1, the uninterruptible power supply system 100 includes a plurality of uninterruptible power supplies (UPS) 11 to 13, a plurality of storage batteries B1 to B3, a plurality of bypass boards UB1 to UB3, and a plurality of units. The circuit breakers CB11, CB12, CB21, CB22, CB31, CB32, CB51, CB52, and the operation switching board UC1 are provided. In the present embodiment, it is assumed that the internal configurations of UPS 11 to 13 are the same as each other, and their capacities (rated output capacities) are also the same as each other.

Each of UPS 11 to 13 includes an AC input terminal T1, a bypass input terminal T2, an AC output terminal T3, a battery terminal T4, a converter 1, an inverter 2, a bypass circuit 3, and a bypass switching circuit 4.

The AC input terminal T1 receives AC power from the commercial AC power source 5 and is connected to the input node of the converter 1. The battery terminal T4 is connected to a DC circuit (DC link) between the output node of the converter 1 and the input node of the inverter 2, and is also connected to the corresponding storage battery B. The AC output terminal T3 is connected to the bypass circuit 3 via the bypass switching circuit 4.

The converter 1 receives commercial frequency AC power from the commercial AC power source 5. The converter 1 converts AC power into DC power during normal times when AC power is supplied from the commercial AC power source 5. The converter 1 is controlled so that the DC voltage supplied to the DC circuit becomes a constant voltage.

The storage battery B is connected to a corresponding UPS DC circuit. The storage battery B normally stores the DC power generated by the converter 1, and supplies the DC power to the inverter 2 in the event of a power failure when the supply of the AC power from the commercial AC power source 5 is stopped.

The inverter 2 is connected to the corresponding DC circuit. The inverter 2 normally converts the DC power generated by the converter 1 into commercial frequency AC power, and in the event of a power failure, converts the DC power from the corresponding storage battery B into commercial frequency AC power. The converter 1 and the inverter 2 correspond to an embodiment of the “power converter”.

The bypass circuit 3 is connected between the bypass input terminal T2 and the bypass switching circuit 4. The bypass switching circuit 4 is connected between the bypass circuit 3 and the AC output terminal T3. The bypass switching circuit 4 switches between electrical connection and disconnection between the bypass circuit 3 and the AC output terminal T3. Specifically, the bypass switching circuit 4 includes a switch connected between the bypass circuit 3 and the AC output terminal T3. The switch is in a non-conducting (off) state when power is supplied from the inverter 2, and is in a conductive (on) state when power is supplied from the bypass circuit 3.

Each of UPS 11 to 13 further includes a control unit (not shown). The control unit controls the converter 1 and the inverter 2 to generate AC power. On the other hand, in the event of a power failure, the control unit stops the converter 1 and controls the inverter 2 to generate AC power. The control unit determines whether or not AC power is normally supplied from the commercial AC power supply 5 based on the voltage of the AC input terminal T1 of each UPS (that is, the AC voltage supplied from the commercial AC power supply 5). .. The control unit controls the converter 1 and the inverter 2 based on the determination result. Further, when the control unit detects the failure of the corresponding UPS, the control unit controls the bypass switching circuit 4 so as to switch the output of the inverter 2 to the output of the bypass circuit 3 without interruption.

The circuit breakers CB11 and CB12 are connected in series between the AC output terminal T3 and the load L1 of the UPS 11. The circuit breakers CB21 and CB22 are connected in series between the AC output terminal T3 and the load L2 of the UPS 12. The circuit breakers CB31 and CB32 are connected in series between the AC output terminal T3 and the load L3 of the UPS 13.

The circuit breaker CB51 is connected between the node between the circuit breaker CB12 and the load L1 and the node between the circuit breaker CB22 and the load L2. The circuit breaker CB 52 is connected between the node between the circuit breaker CB 22 and the load L2 and the node between the circuit breaker CB 32 and the load L3.

Each of the bypass boards UB1 to UB3 has a switch S1 and a switch S2. In each bypass board UB, the switch S1 is connected between the operation switching board UC1 and the bypass input terminal T2. The switch S2 is connected between the commercial AC power supply 5 and the bypass input terminal T2.

The operation switching board UC1 has a plurality of circuit breakers CB13, CB14, CB23, CB24, CB33, and CB34. The circuit breakers CB13 and CB14 are connected in series between the node between the circuit breakers CB11 and CB12 and the switch S1 of the bypass board UB1. The circuit breakers CB23 and CB24 are connected in series between the node between the circuit breakers CB21 and CB22 and the switch S1 of the bypass board UB2. The circuit breakers CB33 and CB34 are connected in series between the node between the circuit breakers CB31 and CB32 and the switch S1 of the bypass board UB3. The node N1 between the circuit breakers CB13 and CB14, the node N2 between the circuit breakers CB23 and CB24, and the node N3 between the circuit breakers CB33 and CB34 are connected to each other.

Each of UPS 11 to 13 is configured to be able to switch from the power supply by the inverter 2 to the power supply by the bypass circuit 3 without interruption by using the bypass switching circuit 4 at the time of maintenance inspection or failure.

The uninterruptible power supply system 100 shown in FIG. 1 prepares three UPSs having such an uninterruptible bypass switching function, one of which is in preliminary operation and the remaining two are in regular operation. It is configured to supply the output of the UPS of the preliminary operation as a bypass power source of the UPS of the normal operation. Since the uninterruptible power supply system 100 is configured to connect the UPS of the preliminary operation in series with the UPS of the normal operation to obtain redundancy, the series redundant uninterruptible power supply system (or the standby redundant uninterruptible power supply system). Is called.

In the following description, the UPS for normal operation is also referred to as "normal UPS", and the UPS for preliminary operation is also referred to as "preliminary UPS". Since the spare UPS commonly acts as a spare UPS for the two regular UPSs, it can also be referred to as a common spare UPS. The capacity of the common spare UPS may be the same as the capacity of the regular UPS, or may be a capacity that can back up two regular UPSs.

Here, in a general series redundant uninterruptible power supply system, by configuring a circuit configuration in which the output of the spare UPS is connected to the input of the bypass circuit of the regular UPS, the regular UPS normally performs load power supply, and the regular UPS is used. It is configured to supply load from the spare UPS in the event of maintenance or inspection or failure.

FIG. 6 is a circuit block diagram showing a configuration of a general series redundant uninterruptible power supply system. With reference to FIG. 6, a general series redundant uninterruptible power supply system 200 includes a plurality of (for example, three) UPS21 to UPS23, circuit breakers CB61 to CB64, CB71 to CB73, and bypass boards UB1 and UB2. The internal configuration of UPS21 to UPS23 is the same as the internal configuration of UPS11 to UPS13 shown in FIG.

In the example of FIG. 6, UPS21 is a spare UPS, and UPS22 and UPS23 are regular UPSs. The circuit breaker CB63 is connected between the AC output terminal T3 of the spare UPS21 and the switch S1 of the bypass board UB1. The circuit breaker CB64 is connected between the AC output terminal T3 of the spare UPS21 and the switch S1 of the bypass board UB2.

The bypass board UB1 has switches S1 and S2. The switch S1 is connected between the circuit breaker CB63 and the bypass input terminal T2 of the regular UPS 22. The switch S2 is connected between the commercial AC power supply 5 and the bypass input terminal T2 of the regular UPS 22.

The bypass board UB2 has switches S1 and S2. The switch S1 is connected between the circuit breaker CB64 and the bypass input terminal T2 of the regular UPS23. The switch S2 is connected between the commercial AC power supply 5 and the bypass input terminal T2 of the regular UPS 23.

The circuit breaker CB72 is connected between the AC output terminal T3 and the load L1 of the regular UPS 22. The circuit breaker CB74 is connected between the AC output terminal T3 and the load L2 of the regular UPS 23. The circuit breakers CB61 and CB71 are connected in series between the AC output terminal T3 and the load L1 of the spare UPS21. The circuit breakers CB62 and CB73 are connected in series between the AC output terminal T3 and the load L2 of the spare UPS21.

As shown in FIG. 6, the circuit breakers CB63 and CB64 are turned on and the circuit breakers CB61 and CB62 are turned off during the load feeding by the regular UPS 22 and the regular UPS 23. Further, the circuit breakers CB72 and CB74 are turned on, and the circuit breakers CB71 and CB73 are turned off. In each of the bypass boards UB1 and UB2, the switch S1 is turned on and the switch S2 is turned off.

In the spare UPS21, the AC input terminal T1 and the bypass input terminal T2 are electrically connected to the commercial AC power supply 5, and the AC output terminal T3 is electrically connected to the bypass input terminal T2 of the regular UPS 22 and the bypass input terminal T2 of the regular UPS 23. Be connected.

In the regular UPS 22, the AC input terminal T1 is electrically connected to the commercial AC power supply 5, the bypass input terminal T2 is electrically connected to the AC output terminal T3 of the spare UPS 21, and the AC output terminal T3 is electrically connected to the load L1. Connected to.

In the regular UPS 23, the AC input terminal T1 is electrically connected to the commercial AC power supply 5, the bypass input terminal T2 is electrically connected to the AC output terminal T3 of the spare UPS 21, and the AC output terminal T3 is electrically connected to the load L2. Connected to.

In this state, the spare UPS 21 stands by in a no-load operation during the load feeding by the regular UPS 22 and the regular UPS 23. Specifically, the spare UPS 21 controls the power converters (converter 1 and inverter 2) to generate AC power, and outputs the generated AC power to the AC output terminal T3. The AC power output from the AC output terminal T3 is input to the bypass input terminals T2 of the regular UPS 22 and the regular UPS 23, as shown by thick solid lines in the figure. Unless the regular UPS 22 and the regular UPS 23 supply power by the bypass circuit 3, the spare UPS 21 is operated without load in the standby state.

FIG. 7 is a diagram illustrating the operation of the series redundant uninterruptible power supply system 200 when a failure of the regular UPS 22 occurs.

With reference to FIG. 7, in the regular UPS 22, when the power supply by the inverter 2 becomes impossible due to the failure of the power converter, the operation of the inverter 2 is stopped by the control unit (not shown) and the bypass switching circuit 4 is turned off. Can be switched on. As a result, as shown by the thick solid line in the figure, AC power is supplied from the bypass circuit 3 to the load L1 via the AC output terminal T3 and the circuit breaker C72. AC power is supplied to the bypass circuit 3 from the spare UPS 21 via the circuit breaker CB63 and the switch S1 of the bypass board UB1. Therefore, the regular UPS 22 can be switched from the power supply by the inverter 2 to the power supply by the spare UPS 21 without interruption.

Although not shown, by switching the circuit breakers CB63 and CB72 from on to off and turning on the circuit breakers CB61 and CB71, a maintenance bypass circuit is provided between the AC output terminal T3 and the load L1 of the spare UPS21. It is formed. With the regular UPS 22 separated from the uninterruptible power supply system, work is performed to repair the failure of the regular UPS 22.

As described above, in the general series redundant uninterruptible power supply system 200, the spare UPS is on standby in the no-load operation while the load is being supplied by the regular UPS. Therefore, the spare UPS tends to have a lower operating rate than the regular UPS. In the specification of the present application, the UPS operating rate refers to the ratio of the UPS operating time to the total operating time of the entire uninterruptible power supply system.

Due to such a difference in operating rate between the spare UPS and the regular UPS, an imbalance may occur in the operating rate among a plurality of UPSs constituting the uninterruptible power supply system. Therefore, even if these plurality of UPSs are introduced at the same time, the regular UPSs will deteriorate over time as compared with the spare UPSs. There is concern that the aging deterioration of this regular UPS will affect the reliability of the uninterruptible power supply system.

Therefore, as shown in FIG. 1, the uninterruptible power supply system 100 according to the present embodiment is configured so that the regular UPS and the spare UPS can be switched between the three UPS 11 to UPS 13. The switching between the regular UPS and the spare UPS can be realized by switching between conduction (on) and uninterruptible power (off) in the circuit breakers CB12, CB22, CB32, the bypass boards UB1 to UB3, and the operation switching board UC1.

In the example of FIG. 1, the circuit breaker CB, the bypass board UB, and the operation switching board UC1 are switched on and off so that the UPS 11 is a spare UPS and the UPS 12 and the UPS 13 are regular UPSs. In the following description, UPS 11 is also referred to as "spare UPS 11", and UPS 12 and UPS 13 are also referred to as "regular UPS 12" and "regular UPS 13", respectively.

Specifically, on the bypass board UB1, the switch S1 is turned off and the switch S2 is turned on. As a result, the bypass input terminal T2 of the spare UPS 11 is electrically connected to the commercial AC power supply 5. The circuit breaker CB11 is turned on and the circuit breaker CB12 is turned off. As a result, the AC output terminal T3 of the spare UPS 11 is electrically connected to the circuit breaker CB13 of the operation switching board UC1 via the circuit breaker CB11.

On the operation switching board UC1, the circuit breakers CB13, CB24 and CB34 are turned on, and the circuit breakers CB14, CB23 and CB33 are turned off. As a result, the AC output terminal T3 of the spare UPS 11 is electrically connected to the switch S1 of the bypass board UB3 via the circuit breakers CB11, CB13 and CB34. Further, the AC output terminal T3 of the spare UPS 11 is electrically connected to the switch S1 of the bypass board UB2 via the circuit breakers CB11, CB13 and CB24.

On the bypass board UB2, the switch S1 is turned on and the switch S2 is turned off. As a result, the AC output terminal T3 of the spare UPS 11 is electrically connected to the bypass input terminal T2 of the regular UPS 12 via the circuit breakers CB11, CB13, CB24 and the switch S1 of the bypass board UB2. The circuit breaker CB21 is turned on and the circuit breaker CB22 is turned on. As a result, the AC output terminal T3 of the regular UPS 12 is electrically connected to the load L2.

On the bypass board UB3, the switch S1 is turned on and the switch S2 is turned off. As a result, the AC output terminal T3 of the spare UPS 11 is electrically connected to the bypass input terminal T2 of the regular UPS 13 via the circuit breakers CB11, CB13, CB34 and the switch S1 of the bypass board UB3. The circuit breaker CB31 is turned on and the circuit breaker CB32 is turned on. As a result, the AC output terminal T3 of the regular UPS 13 is electrically connected to the load L3.

The circuit breaker CB51 is turned on and the circuit breaker CB52 is turned off. As a result, the AC output terminal T3 of the regular UPS 12 is electrically connected to the load L1 via the circuit breakers CB21, CB22 and CB51.

To summarize the above, in the spare UPS 11, the AC input terminal T1 and the bypass input terminal T2 are electrically connected to the commercial AC power supply 5, and the AC output terminal T3 is the bypass input terminal T2 of the regular UPS 12 and the bypass input terminal of the regular UPS 13. It is electrically connected to T2.

In the regular UPS 12, the AC input terminal T1 is electrically connected to the commercial AC power supply 5, the bypass input terminal T2 is electrically connected to the AC output terminal T3 of the spare UPS 11, and the AC output terminal T3 is the load L2 and the load L1. Is electrically connected to.

In the regular UPS 13, the AC input terminal T1 is electrically connected to the commercial AC power supply 5, the bypass input terminal T2 is electrically connected to the AC output terminal T3 of the spare UPS 11, and the AC output terminal T3 is electrically connected to the load L3. Connected to.

In this state, the spare UPS 11 stands by in a no-load operation during the load feeding by the regular UPS 12 and the regular UPS 13. Specifically, the spare UPS 11 controls the power converters (converter 1 and inverter 2) to generate AC power, and outputs the generated AC power to the AC output terminal T3. The AC power output from the AC output terminal T3 is input to the bypass input terminals T2 of the regular UPS 12 and the regular UPS 13 as shown by a thick solid line in the figure. Unless the regular UPS 12 and the regular UPS 13 supply power by the bypass circuit 3, the spare UPS 11 is operated without load in the standby state.

The bypass circuit 3 of the spare UPS 11 receives AC power from the commercial AC power source 5, as shown by the dotted line in the figure. When the spare UPS 11 is maintained or inspected or a failure occurs, the bypass switching circuit 4 can be switched from off to on to switch from the power supply by the inverter 2 to the power supply by the bypass circuit 3 (power supply by the commercial AC power supply 5) without interruption. can.

The regular UPS 12 normally receives AC power from the commercial AC power supply 5 and controls the power converters (converter 1 and inverter 2) to generate AC power, as shown by a single point chain line in the figure. The generated AC power is output to the AC output terminal T3. The AC power output from the AC output terminal T3 is input to the load L1 and the load L2 through the path shown by the alternate long and short dash line in the figure. That is, power is supplied by the inverter 2.

The bypass circuit 3 of the regular UPS 12 receives AC power from the spare UPS 11 as shown by a thick solid line in the figure. When the maintenance and inspection of the regular UPS 12 or the failure occurs, the bypass switching circuit 4 can be switched from off to on to switch from the power supply by the inverter 2 to the power supply by the bypass circuit 3 (power supply by the spare UPS 11) without interruption.

The regular UPS 13 normally receives AC power from the commercial AC power supply 5 and controls the power converters (converter 1 and inverter 2) to generate AC power, as shown by a single point chain line in the figure. The generated AC power is output to the AC output terminal T3. The AC power output from the AC output terminal T3 is input to the load L3 through the path shown by the alternate long and short dash line in the figure. That is, power is supplied by the inverter 2.

The bypass circuit 3 of the regular UPS 13 receives AC power from the spare UPS 11 as shown by a thick solid line in the figure. When the maintenance and inspection of the regular UPS 12 or the failure occurs, the bypass switching circuit 4 can be switched from off to on to switch from the power supply by the inverter 2 to the power supply by the bypass circuit 3 (power supply by the spare UPS 11) without interruption.

Hereinafter, the operation of the uninterruptible power supply system 100 when a failure of the regular UPS 13 occurs will be described with reference to FIGS. 2 and 3.

With reference to FIG. 2, in the regular UPS 13, when the power supply by the inverter 2 becomes impossible due to the failure of the power converter, the operation of the inverter 2 is stopped by the control unit (not shown) and the bypass switching circuit. 4 is switched from off to on. As a result, as shown by the thick solid line in the figure, AC power is supplied from the bypass circuit 3 to the load L3 via the AC output terminal T3 and the circuit breakers C31 and CB32. AC power is supplied to the bypass circuit 3 from the spare UPS 11 via the circuit breakers CB13 and CB34 of the operation switching board UC1. Therefore, the regular UPS 13 can be switched from the power supply by the inverter 2 to the power supply by the spare UPS 11 without interruption.

In this state, the circuit breaker CB33 is switched from off to on in the operation switching board UC1. With the circuit breaker CB33 turned on, the AC output terminal T3 of the spare UPS 11 is electrically connected to the node between the circuit breakers CB31 and CB32 via the circuit breakers CB11, CB13 and CB33. As a result, as shown by the solid line in the figure, a circuit (maintenance bypass circuit) that directly supplies power to the load L3 from the spare UPS 11 is formed.

With reference to FIG. 3, in the operation switching board UC1, when the circuit breaker CB33 is turned on, the circuit breaker CB34 is subsequently turned off. Also, the circuit breaker CB31 is switched from on to off. As a result, the power supply from the spare UPS 11 to the bypass circuit 3 of the regular UPS 13 is cut off, and the AC output terminal T3 of the regular UPS 13 is electrically cut off from the load L3, so that the spare UPS 11 directly feeds the load L3. Only the maintenance bypass circuit will remain.

According to this, when a failure occurs in the regular UPS 13, the load feeding by the regular UPS 13 is switched to the load feeding by the spare UPS 11 by shifting to the feeding by the maintenance bypass circuit through the feeding by the bypass circuit 3. After shifting to the power supply by the maintenance bypass circuit, the repair work of the failure is performed in the regular UPS 13.

Returning to FIG. 2, in the regular UPS 12, when the failure of the regular UPS 13 occurs, the switch S1 of the bypass board UB2 is turned off and the switch S2 is turned on. As a result, the bypass input terminal T2 is electrically connected to the commercial AC power supply 5, and the bypass circuit 3 receives AC power from the commercial AC power supply 5 as shown by the dotted line in the figure. Further, in the operation switching board UC1, the circuit breaker CB24 is switched from on to off, so that the switch S1 of the bypass board UB2 is electrically cut off from the spare UPS 11. That is, after the failure of the regular UPS 13 occurs, the spare UPS 11 backs up the regular UPS 13, so that the power supply to the bypass circuit 3 of the regular UPS 12 is stopped.

As described above, in the uninterruptible power supply system 100, when the maintenance and inspection of the regular UPS 13 or the failure occurs, the load power supply by the regular UPS 12 and the regular UPS 13 is switched to the load power supply by the spare UPS 11 and the regular UPS 12. As a result, the loads L1 to L3 can be continuously fed by the highly reliable UPS even after the failure of the regular UPS 13 occurs.

Although not shown, the load power supply by the regular UPS 12 and the regular UPS 13 can be switched to the load power supply by the spare UPS 11 and the regular UPS 13 according to the same procedure at the time of maintenance and inspection of the regular UPS 12 or when a failure occurs.

Further, in the example of FIG. 1, the configuration in which the load L1 is electrically connected to the AC output terminal T3 of the regular UPS 12 has been described, but between the node between the circuit breaker CB32 and the load L3 and the circuit breaker CB12 and the load L1. By connecting a circuit breaker to the node of the above, the load L1 may be electrically connected to the AC output terminal T3 of the regular UPS 13. Alternatively, the load L1 may not be connected to the regular UPS 12 or the regular UPS 13, and the load L1 may be transferred to at least one of the loads L2 and L3 before operation.

Further, in the uninterruptible power supply system 100, the spare UPS and the regular UPS can be switched between the three UPSs 11 to 13. FIG. 4 shows the configuration of the uninterruptible power supply system 100 when UPS 12 is a spare UPS and UPS 11 and UPS 13 are regular UPS.

With reference to FIG. 4, on the bypass board UB2, the switch S1 is turned off and the switch S2 is turned on. As a result, the bypass input terminal T2 of the spare UPS 12 is electrically connected to the commercial AC power supply 5. The circuit breaker CB21 is turned on and the circuit breaker CB22 is turned off. As a result, the AC output terminal T3 of the spare UPS 12 is electrically connected to the circuit breaker CB23 of the operation switching board UC1 via the circuit breaker CB21.

On the operation switching board UC1, the circuit breakers CB23, CB14 and CB34 are turned on, and the circuit breakers CB13, CB24 and CB33 are turned off. As a result, the AC output terminal T3 of the spare UPS 12 is electrically connected to the switch S1 of the bypass board UB1 via the circuit breakers CB21, CB23 and CB14. Further, the AC output terminal T3 of the spare UPS 12 is electrically connected to the switch S1 of the bypass board UB3 via the circuit breakers CB21, CB23 and CB34.

On the bypass board UB1, the switch S1 is turned on and the switch S2 is turned off. As a result, the AC output terminal T3 of the spare UPS 12 is electrically connected to the bypass input terminal T2 of the regular UPS 11 via the circuit breakers CB21, CB23, CB14 and the switch S1 of the bypass board UB1. The circuit breaker CB11 is turned on and the circuit breaker CB12 is turned on. As a result, the AC output terminal T3 of the regular UPS 11 is electrically connected to the load L1.

On the bypass board UB3, the switch S1 is turned on and the switch S2 is turned off. As a result, the AC output terminal T3 of the spare UPS 12 is electrically connected to the bypass input terminal T2 of the regular UPS 13 via the circuit breakers CB21, CB23, CB34 and the switch S1 of the bypass board UB3. The circuit breaker CB31 is turned on and the circuit breaker CB32 is turned on. As a result, the AC output terminal T3 of the regular UPS 13 is electrically connected to the load L3.

The circuit breaker CB51 is turned on and the circuit breaker CB52 is turned off. As a result, the AC output terminal T3 of the regular UPS 11 is electrically connected to the load L2 via the circuit breakers CB11, CB12 and CB51.

To summarize the above, in the spare UPS 12, the AC input terminal T1 and the bypass input terminal T2 are electrically connected to the commercial AC power supply 5, and the AC output terminal T3 is the bypass input terminal T2 of the regular UPS 11 and the bypass input terminal of the regular UPS 13. It is electrically connected to T2.

In the regular UPS 11, the AC input terminal T1 is electrically connected to the commercial AC power supply 5, the bypass input terminal T2 is electrically connected to the AC output terminal T3 of the spare UPS 12, and the AC output terminal T3 is the load L1 and the load L2. Is electrically connected to.

In the regular UPS 13, the AC input terminal T1 is electrically connected to the commercial AC power supply 5, the bypass input terminal T2 is electrically connected to the AC output terminal T3 of the spare UPS 12, and the AC output terminal T3 is electrically connected to the load L3. Connected to.

In this state, the spare UPS 12 stands by in a no-load operation during the load feeding by the regular UPS 11 and the regular UPS 13. Specifically, the spare UPS 12 controls the power converters (converter 1 and inverter 2) to generate AC power, and outputs the generated AC power to the AC output terminal T3. The AC power output from the AC output terminal T3 is input to the bypass input terminals T2 of the regular UPS 11 and the regular UPS 13 as shown by a thick solid line in the figure. Unless the regular UPS 11 and the regular UPS 13 supply power by the bypass circuit 3, the spare UPS 12 is operated without load in the standby state.

The bypass circuit 3 of the spare UPS 12 receives AC power from the commercial AC power source 5, as shown by the dotted line in the figure. When the spare UPS 12 is maintained or inspected or a failure occurs, the bypass switching circuit 4 can be switched from off to on to switch from the power supply by the inverter 2 to the power supply by the bypass circuit 3 (power supply by the commercial AC power supply 5) without interruption. can.

The regular UPS 11 normally receives AC power from the commercial AC power supply 5 and controls the power converters (converter 1 and inverter 2) to generate AC power, as shown by a single point chain line in the figure. The generated AC power is output to the AC output terminal T3. The AC power output from the AC output terminal T3 is input to the load L1 and the load L2 through the path shown by the alternate long and short dash line in the figure. That is, power is supplied by the inverter 2.

The bypass circuit 3 of the regular UPS 11 receives AC power from the spare UPS 12 as shown by a thick solid line in the figure. When the maintenance and inspection of the regular UPS 11 or the failure occurs, the bypass switching circuit 4 can be switched from off to on to switch from the power supply by the inverter 2 to the power supply by the bypass circuit 3 (power supply by the spare UPS 12) without interruption.

The regular UPS 13 normally receives AC power from the commercial AC power supply 5 and controls the power converters (converter 1 and inverter 2) to generate AC power, as shown by a single point chain line in the figure. The generated AC power is output to the AC output terminal T3. The AC power output from the AC output terminal T3 is input to the load L3 through the path shown by the alternate long and short dash line in the figure. That is, power is supplied by the inverter 2.

The bypass circuit 3 of the regular UPS 13 receives AC power from the spare UPS 12 as shown by a thick solid line in the figure. When the maintenance and inspection of the regular UPS 13 or the failure occurs, by switching the bypass switching circuit 4 from off to on, it is possible to switch from the power supply by the inverter 2 to the power supply by the bypass circuit 3 (power supply by the spare UPS 12) without interruption.

As is clear by comparing FIGS. 1 and 4, the circuit breakers (circuit breakers CB12, CB22, CB32) connected between the AC output terminal T3 of each UPS and the load, and the circuit breaker included in the operation switching board UC1. (Circuit breakers CB13, CB14, CB23, CB24, CB33, CB34) and by switching the on / off of switches S1 and S2 in each bypass board UB1 to UB3, the regular UPS and the spare UPS are among the three UPS11 to UPS13. Can be switched. According to this, the user of the uninterruptible power supply system 100 can arbitrarily select a spare UPS from the three UPS 11 to UPS 13.

Therefore, for example, by periodically replacing the spare UPS and the regular UPS while observing the operating rate of each UPS, the operating rate can be leveled among the three UPS 11 to UPS 13. In this case, the circuit breaker CB, the operation switching board UC1 and the bypass board UB are switched on and off at regular intervals so that the UPS having the highest operating rate in the immediately preceding fixed period is used as the spare UPS in the next fixed period. By doing so, it is possible to reduce the variation in the operating rates of the three UPSs 11 to 13. According to this, since the progress of aging deterioration of the regular UPS can be suppressed, the reliability of the uninterruptible power supply system 100 as a whole can be improved.

Alternatively, when a UPS with a short usage period is introduced into any one of the three UPSs 11 to UPS13, the introduced UPS is used as a regular UPS, and the remaining two UPSs with a long usage period are used. The UPS can be configured to switch on / off of the circuit breaker, the operation switching board UC1 and the bypass boards UB1 to UB3 so that the UPS of the above is used as a spare UPS. According to this, since the UPS having a relatively short usage period is assigned to the regular UPS among the three UPSs 11 to 13, the reliability of the uninterruptible power supply system 100 as a whole can be improved.

In the above-described embodiment, the switching between the normal UPS and the spare UPS in the configuration in which the uninterruptible power supply system 100 includes three UPS11 to UPS13 has been described, but in the uninterruptible power supply system having four or more UPSs. By applying the same method, the same effect can be obtained.

FIG. 5 is a circuit block diagram showing a configuration when the number of UPS is increased to four in the uninterruptible power supply system 100 shown in FIG.

With reference to FIG. 5, the uninterruptible power supply system 100 is an uninterruptible power supply system 100 shown in FIG. 1 with UPS 14 added. The UPS 14 is used as a regular UPS for supplying power to the load L4. It is assumed that the internal configuration of UPS14 is the same as the internal configuration of UPS11 to UPS13, and the capacity thereof is also the same.

The uninterruptible power supply system 100 further includes circuit breakers CB41, CB42, CB53 and a bypass board UB4. The circuit breakers CB41 and CB42 are connected in series between the AC output terminal T3 and the load L4 of the UPS 14.

The circuit breaker CB53 is connected between the node between the circuit breaker CB42 and the load L4 and the node between the circuit breaker CB32 and the load L3.

The bypass board UB4 has a switch S1 and a switch S2. The switch S1 is connected between the operation switching board UC1 and the bypass input terminal T2. The switch S2 is connected between the commercial AC power supply 5 and the bypass input terminal T2.

The operation switching board UC1 further includes circuit breakers CB43 and CB44. The circuit breakers CB43 and CB44 are connected in series between the node between the circuit breakers CB41 and CB42 and the switch S1 of the bypass board UB4. The node N1 between the circuit breakers CB13 and CB14, the node N2 between the circuit breakers CB23 and CB24, the node N3 between the circuit breakers CB33 and CB34, and the node N4 between the circuit breakers CB43 and CB44 are connected to each other.

On the operation switching board UC1, the circuit breakers CB13, CB24, CB34 and CB44 are turned on, and the circuit breakers CB14, CB23, CB33 and CB43 are turned off. As a result, the AC output terminal T3 of the spare UPS 11 is electrically connected to the switch S1 of the bypass board UB4 via the circuit breakers CB11, CB13 and CB44.

On the bypass board UB4, the switch S1 is turned on and the switch S2 is turned off. As a result, the AC output terminal T3 of the spare UPS 11 is electrically connected to the bypass input terminal T2 of the regular UPS 14 via the circuit breakers CB11, CB13, CB44 and the switch S1 of the bypass board UB4. The circuit breaker CB41 is turned on and the circuit breaker CB42 is turned on. As a result, the AC output terminal T3 of the regular UPS 14 is electrically connected to the load L4.

Also in the uninterruptible power supply system 100 shown in FIG. 5, the circuit breakers (circuit breakers CB12, CB22, CB32, CB42) connected between the AC output terminal T3 of each UPS and the load L, and the circuit breaker included in the operation switching board UC1 are included. By switching the on / off of the device (circuit breaker CB13, CB14, CB23, CB24, CB33, CB34, CB43, CB44) and the switches S1 and S2 in each bypass board UB1 to UB4, it is regularly used among the four UPS11 to UPS14. You can switch between UPS and spare UPS. Therefore, since the operating rates of the four UPSs can be leveled, it is possible to suppress the deterioration of the reliability of the uninterruptible power supply system 100 due to the progress of the aged deterioration of the regular UPS.

As described above, switching between the spare UPS and the regular UPS in the uninterruptible power supply system according to the embodiment shown in FIG. 1 is performed by the circuit breakers CB12 and CB22 connected between the AC output terminal T3 of each UPS and the load. , CB32, operation switching board UC1 and bypass board UB1 to UB3 are realized by switching on and off. That is, the circuit breakers CB12, CB22, CB32, the operation switching board UC1 and the bypass boards UB1 to UB3 form a "switching device" for switching between the regular UPS and the spare UPS among the three UPSs 11 to 13.

In order to switch between the regular UPS and the spare UPS between the first UPS and the second UPS included in the uninterruptible power supply system according to the embodiment, the switching device is used for the AC output terminal T3 of the first UPS and the AC output terminal T3 of the first UPS. The "second and second" electrically connected in series between the "first switch" connected between the loads and the AC output terminal T3 of the first UPS and the bypass input terminal T2 of the second UPS. Of the "3 switch", the "fourth switch" connected between the second UPS AC output terminal and the load, the second UPS AC output terminal T3, and the first UPS bypass input terminal T2. The "fifth and sixth switches" electrically connected in series between them, and the "seventh switch" that selectively connects the bypass input terminal T2 of the first UPS to either the AC power supply or the sixth switch. It has a "switch" and an "eighth switch" that selectively connects the bypass input terminal T2 of the second UPS to either the AC power supply or the third switch.

In the example of FIG. 1, when UPS 11 is set to "first UPS" and UPS 13 is set to "second UPS", the circuit breaker CB12 corresponds to the "first switch", and the circuit breaker CB13 and the circuit breaker CB13 of the operation switching board UC1 The CB34 corresponds to the "second and third switches", the circuit breaker CB32 corresponds to the "fourth switch", and the circuit breakers CB33 and CB14 of the operation switching board UC1 correspond to the "fifth and sixth switches". Corresponds to each. The bypass board UB1 corresponds to the "seventh switch", and the bypass board UB3 corresponds to the "eighth switch".

In the above configuration, when the first UPS (UPS11) is a spare UPS and the second UPS (UPS13) is a regular UPS, the first switch (circuit breaker CB12) is turned off, and the second and second UPSs are used. The switch of 3 (circuit breaker CB13, CB34) is turned on, the fourth switch (circuit breaker CB32) is turned on, and the fifth and sixth switches (circuit breaker CB33, CB14) are turned off. Further, the seventh switch (bypass board UB1) connects the bypass input terminal T2 of the first UPS to the AC power supply (commercial AC power supply 5), and the eighth switch (bypass board UB3) connects the second UPS. Bypass input terminal T2 is connected to a third switch (circuit breaker CB34).

On the other hand, when the first UPS (UPS11) is a regular UPS and the second UPS (UPS13) is a spare UPS, the first switch (circuit breaker CB12) is turned on, and the second and third UPSs are turned on. (Circuit breakers CB13, CB34) are turned off, the fourth switch (circuit breaker CB32) is turned off, and the fifth and sixth switches (circuit breakers CB33, CB14) are turned on. Further, the seventh switch (bypass board UB1) connects the bypass input terminal T2 of the first UPS to the sixth switch (circuit breaker CB14), and the eighth switch (bypass board UB3) is the second switch. Connect the UPS bypass input terminal T2 to the AC power supply (commercial AC power supply 5).

The on / off switching of the first to eighth switches may be manually performed by the user, or may be performed by the control device that controls the uninterruptible power supply system 100 in an integrated manner. Alternatively, the control units of the UPSs may cooperate with each other by exchanging information with each other.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 converter, 2 inverter, 3 bypass circuit, 4 bypass switching circuit, 5 commercial AC power supply, 11-13, 21-23 UPS, 100, 200 uninterruptible power supply system, T1 AC input terminal, T2 bypass input terminal, T3 AC output Terminal, T4 battery terminal, B1 to B4 storage battery, CB11 to CB14, CB21 to CB24, CB31 to CB34, CB41 to CB44, CB51 to CB53, CB61 to CB64, CB71 to CB74 breaker, UB1 to UB4 bypass board, UC1 operation switching Board, L1 to L4 load.

Claims (5)

The first uninterruptible power supply and
The second uninterruptible power supply and
A switching device for switching between a regular uninterruptible power supply device and a spare uninterruptible power supply device between the first and second uninterruptible power supply devices is provided.
Each of the first and second uninterruptible power supplies
With the AC input terminal connected to the AC power supply,
AC output terminal for supplying AC power to the load,
A power converter connected between the AC input terminal and the AC output terminal to generate AC power to be supplied to the load.
Bypass input terminal and
A bypass circuit connected in parallel with the power converter between the bypass input terminal and the AC output terminal.
Includes a bypass switching circuit that switches between electrical connection and disconnection between the bypass circuit and the AC output terminal.
The bypass switching circuit electrically cuts off the bypass circuit and the AC output terminal when power is supplied by the power converter, while the bypass circuit and the AC output terminal are used for maintenance and inspection of the uninterruptible power supply or when a failure occurs. It is configured to be electrically connected to the output terminal,
The switching device is
A first switch electrically connected between the AC output terminal of the first uninterruptible power supply and the load.
A second and third switch electrically connected in series between the AC output terminal of the first uninterruptible power supply and the bypass input terminal of the second uninterruptible power supply.
A fourth switch electrically connected between the AC output terminal of the second uninterruptible power supply and the load.
Includes fifth and sixth switches electrically connected in series between the AC output terminal of the second uninterruptible power supply and the bypass input terminal of the first uninterruptible power supply. The node between the second and third switches is electrically connected to the node between the fifth and sixth switches.
A seventh switch that selectively connects the bypass input terminal of the first uninterruptible power supply to either the AC power supply or the sixth switch.
An uninterruptible power supply system further comprising an eighth switch that selectively connects the bypass input terminal of the second uninterruptible power supply to any of the AC power supply and the third switch. When the first uninterruptible power supply is used as the spare uninterruptible power supply and the second uninterruptible power supply is used as the regular uninterruptible power supply, the switching device is used.
While turning off the first switch, turning on the second and third switches,
While turning on the fourth switch, turning off the fifth and sixth switches,
The seventh switch connects the bypass input terminal of the first uninterruptible power supply to the AC power supply.
The uninterruptible power supply system according to claim 1, wherein the eighth switch connects the bypass input terminal of the second uninterruptible power supply device to the third switch. When the first uninterruptible power supply device is used as the spare uninterruptible power supply device and the second uninterruptible power supply device is used as the regular uninterruptible power supply device, maintenance and inspection of the second uninterruptible power supply device or The uninterruptible power supply system according to claim 2, wherein when a failure occurs, the switching device turns on the fifth switch and then turns off the third switch. When the second uninterruptible power supply is used as the spare uninterruptible power supply and the first uninterruptible power supply is used as the regular uninterruptible power supply, the switching device is used.
While turning off the fourth switch, turning on the fifth and sixth switches,
While turning on the first switch, turning off the second and third switches,
The seventh switch connects the bypass input terminal of the first uninterruptible power supply to the sixth switch.
The uninterruptible power supply system according to any one of claims 1 to 3, wherein the eighth switch connects the bypass input terminal of the second uninterruptible power supply device to the AC power supply. When the second uninterruptible power supply device is used as the spare uninterruptible power supply device and the first uninterruptible power supply device is used as the regular uninterruptible power supply device, maintenance and inspection of the first uninterruptible power supply device or The uninterruptible power supply system according to claim 4, wherein when a failure occurs, the switching device turns on the second switch and then turns off the sixth switch.

Images