JP2021040398A - Uninterruptible power supply device - Google Patents

Abstract

To provide an uninterruptible power supply device in which a storage current to a power storage device can be adjusted by a simple system.SOLUTION: An uninterruptible power supply device includes an AC-DC converter that converts an AC voltage to a DC voltage, a DC-AC converter that converts a DC voltage to an AC voltage, and supplies the AC voltage to an AC load, a power storage device that is connected in parallel with the DC-AC converter, and is provided for supplying power to the AC load by storing a DC voltage, and a controller that controls a storage current to the power storage device in accordance with the AC load. The controller includes a storage unit in which a plurality of power operating patterns for predicting the AC load fluctuating according to a time zone are stored, and a current control unit that controls the storage current to the power storage device in accordance with the power operating patterns stored in the storage unit.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an uninterruptible power supply that switches a power supply circuit to a load when a commercial power supply fails.

Conventionally, an uninterruptible power supply device that supplies electric power to a load from a power storage device when a commercial power supply fails has been known (Patent Document 1).

Japanese Unexamined Patent Publication No. 7-170677

In this respect, a configuration is shown in which the storage current in the power storage device can be adjusted according to the fluctuation of the load. Control can be complicated when constantly monitoring and adjusting load fluctuations.

On the other hand, load fluctuations can be predicted to some extent and can be adjusted based on the predictions.

The present disclosure has been made to solve the above problems, and provides an uninterruptible power supply capable of adjusting the stored current in the power storage device by a simple method.

A non-disruptive power supply device that follows a certain aspect is an AC-DC converter that converts AC voltage to DC voltage, a DC-AC converter that converts DC voltage to AC voltage and supplies it to an AC load, and a DC-AC converter in parallel. It is provided with a power storage device that is connected and stores DC voltage to supply power to an AC load, and a controller that controls the storage current in the power storage device according to the AC load. The controller has a storage unit that stores a plurality of power operation patterns that predict an AC load that fluctuates according to the time zone, and a current control unit that controls the storage current in the power storage device according to the power operation pattern stored in the storage unit. Including.

Preferably, the current control unit adjusts the AC / DC converter to control the stored current in the power storage device.

Preferably, a chopper circuit is provided which is connected between the DC AC converter and the power storage device and adjusts the voltage level of the DC voltage. The current control unit adjusts the chopper circuit to control the stored current.

Preferably, the plurality of power operation patterns are set so that the maximum AC load differs depending on the time zone, and one of the plurality of power operation patterns is assigned according to the day of the week.

Preferably, the current control unit sets the maximum value of the stored current in the power storage device according to the power operation pattern.

According to one embodiment, the uninterruptible power supply can safely restore the power storage device.

It is a figure explaining the structure of the uninterruptible power supply device 10 based on an embodiment. It is a figure explaining the electric power operation pattern stored in the storage part 42 based on embodiment. It is a flow diagram explaining the control of the current control unit 40 based on an embodiment. It is a figure explaining the charging method of the conventional uninterruptible power supply. It is a figure explaining the charging system of the uninterruptible power supply 10 according to this embodiment.

This embodiment will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated.

FIG. 1 is a diagram illustrating a configuration of an uninterruptible power supply device 10 based on an embodiment.
As shown in FIG. 1, the uninterruptible power supply 10 is connected to the AC input power supply 3 and the load 20.

The AC input power supply 3 is an AC power source that supplies AC power to the uninterruptible power supply device 10. The input power source is composed of, for example, a commercial AC power source or a private power generator.

A three-phase three-wire (3φ3W) type is shown as an example of an input AC power supply. However, the type of input AC power supply is not limited to the three-phase three-wire system, and may be, for example, a three-phase four-wire power supply or a single-phase three-wire power supply.

The uninterruptible power supply 10 includes a converter 5, a power storage device 30, an inverter 7, a chopper circuit 6, and a controller 4 that controls the entire uninterruptible power supply 10.

The converter 5 and the inverter 7 are connected in series between the AC input power supply 3 and the load 20.

The power storage device 30 is connected to the converter 5 in parallel with the inverter 7 via a chopper circuit 6.

The converter 5 converts the AC voltage supplied from the AC input power supply 3 into a DC voltage. The inverter 7 converts the DC voltage converted by the converter 5 into an AC voltage.

The chopper circuit 6 converts the voltage level of the DC voltage and supplies it to the power storage device 30.
Each of the converter 5, the chopper circuit 6, and the inverter 7 is controlled by the controller 4.

The power storage device 30 includes a switch 32 and a secondary battery 34.
The power storage device 30 is a device for supplying a DC voltage to the inverter 7 when the AC input power supply 3 cannot supply the AC voltage (for example, at the time of a power failure). The switch 32 is conducting, and the converter 5 charges the secondary battery 34.

Normally, when AC power is supplied from the AC input power supply 3, the DC voltage generated by the converter 5 is stored in the power storage device 30, and is converted into AC voltage by the inverter 7 and supplied to the load 20. On the other hand, in the event of a power failure when the supply of AC voltage from the AC input power supply 3 is stopped, the operation of the converter 5 is stopped, and the DC voltage stored in the power storage device 30 is converted into AC voltage by the inverter 7 and supplied to the load 20. To. Therefore, according to the uninterruptible power supply, the operation of the load 20 can be continued by using the electric power stored in the power storage device 30 even in the event of a power failure.

The controller 4 is a control device for controlling a converter 5, a chopper circuit 6, a power storage device 30, and an inverter 7 in order to generate an AC voltage to be supplied to the load 20 during normal times and power failure. As an example, the controller 4 is a control device. It is mainly composed of a microcomputer including a CPU (Central Processing Unit) and a storage unit such as a ROM (Read Only Memory) and a RAM (Random Access Memory). Then, the controller 4 controls the converter 5, the chopper circuit 6, the power storage device 30, the inverter 7, and the like by having the CPU read the program stored in the ROM or the like in advance into the RAM and execute the program.

At least a part of the controller 4 may be configured to execute a predetermined numerical / logical operation process by hardware such as an electronic circuit.

The controller 4 includes a current control unit 40 for controlling the stored current for charging the secondary battery 34 of the power storage device 30, and a storage unit 42.

FIG. 2 is a diagram illustrating a power operation pattern stored in the storage unit 42 based on the embodiment.

As shown in FIG. 2, a plurality of electric power operation patterns are stored in the storage unit 42.
In this example, power operation patterns A to C are provided.

For each power operation pattern, the predicted amount of AC load that fluctuates according to the time zone is set.
As an example, the electric power operation pattern A is a normal electric power operation pattern, and as an example, the time zone of "0:00 to 9:00" is set to "30%". The time zone of "9:00 to 19:00" is set to "70%". The time zone of "19:00 to 24:00" is set to "30%".

The predicted amount here indicates the ratio of the uninterruptible power supply 10 to the maximum amount of power that can be supplied to the load 20 by receiving the input of the AC voltage.

For example, if the uninterruptible power supply 10 can supply 200 kW, 70% will be 140 kW. In this example, the case where the ratio is set will be described, but the ratio is not particularly limited, and the amount of electric power may be used, or other values may be used.

The electric power operation pattern B is an electric power operation pattern in the case of operating at midnight, and as an example, the time zone of "0:00 to 1:00" is set to "30%". The time zone of "1:00 to 2:00" is set to "100%". In the power operation pattern A, the time zone of "2:00 to 24:00" is set to "30%".

The electric power operation pattern C is an electric power operation pattern when operating on a holiday, and the time zone of "0:00 to 24:00" is set to "30%".

Further, the storage unit 42 shows a case where the power operation pattern is assigned to each day of the week.

Specifically, power operation patterns are assigned from Sunday to Saturday. For example, Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, and Saturday are assigned to power operation patterns "C", "A", "B", "A", "A", "B", and "B", respectively. The case is shown.

FIG. 3 is a flow chart illustrating control of the current control unit 40 based on the embodiment.
As shown in FIG. 3, the current control unit 40 acquires the power operation pattern (step S2). Specifically, the power operation pattern matched to the day of the week among the plurality of power operation patterns stored in the storage unit 42 is acquired.

In this example, for example, the power operation pattern "A" is acquired.
Next, the current control unit 40 acquires the planned maximum load amount (step S4).

Specifically, the planned maximum load amount according to the time zone in the power operation pattern is acquired.

In this example, "70%" of the time zone of "9:00 to 19:00" is acquired. For example, if the uninterruptible power supply 10 can supply 200 kW, 70% will be 140 kW.

Next, the current control unit 40 calculates the maximum limit charge amount (step S6). Specifically, the current control unit 40 calculates the maximum limit charge amount based on the planned maximum load amount and the amount of electric power that can be supplied. For example, 200 kW-140 kW = 60 kW is the amount of electric power that can be used to store the power storage device 30.

The current control unit 40 calculates the maximum limit charge amount based on the electric energy amount.
Next, the current control unit 40 acquires load information (step S8).

Specifically, the current control unit 40 measures the amount of current actually supplied from the uninterruptible power supply 10 to the load 20 and acquires load information.

Next, the current control unit 40 calculates the amount of chargeable current (step S10).
Specifically, the current control unit 40 calculates the chargeable current amount based on the measured actual load information. For example, when the load amount of the actual load 20 exceeds the planned maximum load amount, the chargeable current amount becomes small. On the other hand, when the load amount of the actual load 20 does not exceed the planned maximum load amount, the chargeable current amount becomes large.

Next, the current control unit 40 determines whether or not the chargeable current amount is within the maximum limit charge amount (step S12).

When the current control unit 40 determines that the chargeable current amount is within the maximum limit charge amount (YES in step S12), the current control unit 40 sets the current amount of the stored current to the chargeable current amount (step S14). Specifically, the current control unit 40 instructs the chopper circuit 6 to adjust the amount of stored current. For example, it is possible to adjust the amount of stored current by adjusting the voltage level converted by the chopper circuit 6.

Then, the process ends (end).
On the other hand, when the current control unit 40 determines that the chargeable current amount is not within the maximum limit charge amount (NO in step S12), the current amount of the stored current is set to the maximum limit charge amount (step S14). Specifically, the current control unit 40 instructs the chopper circuit 6 to adjust the amount of stored current. For example, it is possible to adjust the amount of stored current by adjusting the voltage level converted by the chopper circuit 6.

Then, the process ends (end).
When it is determined that the chargeable current amount is within the maximum limit charge amount, power is supplied from the uninterruptible power supply 10 to the load 20 more than the rating by setting the current amount of the stored current to the chargeable current amount. It is possible to suppress this.

When it is determined that the chargeable current amount is not within the maximum limit charge amount, that is, the chargeable current amount is larger than the maximum limit charge amount, the current amount of the stored current is set to the maximum limit charge amount. By limiting the amount of charge to the maximum limit, it is possible to suppress the supply of electric power from the uninterruptible power supply 10 to the load 20 beyond the rating even when the load fluctuates. It is also possible to prevent the stored current from increasing and overcharging. According to this method, it is possible to adjust the stored current in the power storage device 30 by a simple method according to the power operation pattern stored in the storage unit 42.

FIG. 4 is a diagram illustrating a charging method of a conventional uninterruptible power supply.
As shown in FIG. 4, when the amount of the storage current for charging the power storage device 30 is constant, it takes time to complete the charging of the power storage device 30.

FIG. 5 is a diagram illustrating a charging method of the uninterruptible power supply 10 according to the present embodiment.
As shown in FIG. 5, it is possible to significantly shorten the time until the charging of the power storage device 30 is completed by changing the amount of the storage current according to the load.

As a result, even if a power failure occurs during charging, it is possible to secure a long dischargeable time.

In this example, the case where the chopper circuit 6 is instructed to adjust the amount of stored current is described as an example, but instead of adjusting the chopper circuit 6, for example, the converter 5 is directly instructed to perform conversion. It is also possible to adjust the amount of stored current by adjusting the amount of electric power to be stored. Further, it is also possible to configure the configuration in which the chopper circuit 6 is not provided.

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 not by the above description but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

3 AC input power supply, 4 controller, 5 converter, 6 chopper circuit, 7 inverter, 10 uninterruptible power supply, 20 load, 40 current control unit, 42 storage unit.

Claims (5)

An AC-DC converter that converts AC voltage to DC voltage,
A DC AC converter that converts the DC voltage into an AC voltage and supplies it to an AC load.
A power storage device connected in parallel with the DC AC converter to store the DC voltage and supply power to the AC load.
A controller for controlling the storage current in the power storage device according to the AC load is provided.
The controller
A storage unit that stores a plurality of power operation patterns that predict the AC load that fluctuates according to the time zone, and
An uninterruptible power supply including a current control unit that controls a storage current in the power storage device according to a power operation pattern stored in the storage unit. The uninterruptible power supply according to claim 1, wherein the current control unit adjusts the AC / DC converter to control the stored current in the power storage device. A chopper circuit connected between the DC AC converter and the power storage device and adjusting the voltage level of the DC voltage is provided.
The uninterruptible power supply according to claim 1, wherein the current control unit adjusts the chopper circuit to control the stored current. The plurality of power operation patterns are set so that the maximum AC load differs depending on the time zone.
The uninterruptible power supply according to claim 1, wherein one of the plurality of power operation patterns is assigned according to the day of the week. The uninterruptible power supply according to claim 1, wherein the current control unit sets the maximum value of the stored current in the power storage device according to the power operation pattern.

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