JP2002315228A - Power supply apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a voltage drop due to the memory effect of a secondary cell 20 in uninterruptible power source equipment which supplies DC power to a load 35 exclusively from a commercial AC power source 1 at a normal operation, which supplies or charges the DC power to the load from the cell 20 instead of or in addition to the commercial power source 1. SOLUTION: The secondary cell 20 has two systems in a main secondary cell 20a and a sub-secondary cell 20b. Furthermore, the secondary cell is forcibly discharged to a set voltage which can refresh the secondary cell each time the cell is charged and discharged for each predetermined period or the predetermined number of times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply for communication and information equipment which converts an AC input into DC power and supplies it to a load, and more particularly to an uninterruptible function using a secondary battery as an auxiliary power supply at the time of power failure. Regarding the power supply that you have.

[0002]

2. Description of the Related Art Conventionally, this type of power supply device is an uninterruptible power supply device (hereinafter referred to as "U.
PS), and in the event of a power failure, the output is instantaneously switched from the commercial AC power supply to the auxiliary power supply, so that communication and information equipment such as computer equipment, data storage equipment, network equipment, or its application equipment at work. Is prevented from being stopped unnecessarily.

[0003]

However, in recent years, the power situation has improved, and although the probability of occurrence of a power outage that would necessitate a forced stoppage of these devices has been extremely small, it has been large just in case. It is wasteful to prepare the UPS separately from the computer device and make it stand by.

On the other hand, in communication / information devices, a CPU
As a result, the power consumption of the load is reduced during steady-state operation, except for special cases such as the initial stage of startup, so that it can supply short-time peak power only. In addition, a large-capacity AC power supply must be prepared. Further, this type of AC power supply is 100-200
It is common to convert an AC high voltage of V to a DC low voltage of about 3 V, usually requiring three stages of power conversion, and the conversion efficiency from AC power to DC power is poor, making it difficult to save power.

[0005] From the above viewpoints, the AC power supply is downsized by supplying a part of the peak power from the secondary battery, and the AC power supply is stopped while the power consumption in the load is small. By configuring to supply power from the secondary battery, it is possible to prevent power loss in the AC power supply and improve the efficiency of the power supply device as a whole while maintaining the function as a backup power supply during a power outage. We are studying power supply units. As secondary batteries used in these devices, nickel-metal hydride batteries or nickel cadmium batteries are suitable because of the demand for miniaturization and high output, but due to the nature of these devices, some batteries are partially used. Since charging and discharging are repeated many times, a voltage drop due to a memory effect is a problem.

The present invention has been made in view of such inconvenience, and in a power supply device for converting commercial AC power to DC power and supplying power to a load, the power supply device uses an auxiliary battery using a secondary battery. A power supply unit is mounted, and the auxiliary power supply unit has a function of supplying or charging power according to set conditions. Further, by mounting a plurality of secondary batteries in the auxiliary power supply unit, An object of the present invention is to provide a power supply device capable of refreshing a memory effect periodically or at every predetermined use value without impairing a power supply function of a secondary battery.

[0007]

A power supply device 4 according to the present invention is connected to a commercial AC power supply 1 as shown schematically in FIG. 1, and converts the commercial AC power into DC power. A main power supply unit 2 that can supply power to a load;
A secondary battery 20 serving as a power supply source, and an auxiliary power supply unit 3 capable of supplying power to a load 35 instead of or in addition to the main power supply unit 2; A plurality of sets 20 are provided that operate in conjunction with each other and that can be charged and discharged independently.

The auxiliary power supply unit 3 includes a charging / discharging means 5 for the secondary battery 20, a switching means 9 for switching the secondary battery 20 charged / discharged by the charging / discharging means 5, Battery capacity detecting means 6 and charging / discharging means 5
And a control means 7 for regulating the charge / discharge amount and charge / discharge timing in the main power supply unit 2 based on the remaining capacity of the secondary battery 20 and the required power amount on the load side. A predetermined control operation interlocked with is performed.

The above-mentioned secondary battery 20 includes a main secondary battery 20.
a and the secondary battery 20b.
Is set to have a smaller battery capacity than the main secondary battery 20a. The secondary battery 20 forcibly discharges to a predetermined voltage when a predetermined condition such as a predetermined time elapse or a predetermined number of times of charging / discharging is reached, so that the memory effect accumulated by partial charging / discharging is obtained. Is configured to be erased (refreshed).

It is preferable that the above-mentioned power supply device 4 is integrally incorporated in a communication / information device 8 such as a computer device, a data storage device, and a network device.
As the secondary battery 20, a nickel hydrogen battery or a nickel cadmium battery is used.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a power supply device according to the present invention will be described.
FIG. 3 shows an example in which the present invention is applied to an uninterruptible power supply unit 11 in the server computer device 10 shown in FIG. However, the present invention is not limited to this, and may be applied to a power supply in various electronic devices (communication / information devices) that require a constant operation or a power supply device that operates independently to supply power to such electronic devices. Of course, it can be implemented almost in the same way.

The power supply unit 11 according to the present invention is, for example, 100 units as schematically shown in FIG.
Is connected to a commercial AC power supply 1 that outputs an AC voltage V1 of about 200 V to a low voltage of about 1 to 5 V DC for various loads 35 including a CPU 35 a, a memory 35 b, and an input / output unit (I / O) 35 c. DC voltages V4 and V5 can be supplied.

The power supply section 11 includes an AC-DC converter 30 and a DC-DC converter 31 for converting the commercial AC voltage V1 into a DC voltage V3 of, for example, about 48 V, and a DC voltage V4 · DC-DC converter 32 for converting to V5 and VRM (Volt
age Regulator Module) 33,
And a secondary battery device 12.

In the main power supply system, the input AC voltage V1 is 200
In the case of V, the AC-DC converter 30 converts the DC voltage to a high DC voltage V2 of about 360 V, and then the DC-DC converter 31 reduces the DC voltage to a medium DC voltage V3 of 48 V DC. With this configuration, the power factor can be improved and power supply harmonics can be suppressed. Note that the number of the AC-DC converters 30 and the DC-DC converters 31 and 32 is not always one. Depending on the required load, there may be a plurality of them, or there may be more than a necessary number to provide redundancy and increase reliability. Further, the final output voltage is not always limited to V4 and V5.

The secondary battery device 12 includes a secondary battery 20 having a main secondary battery 20a having a battery voltage V6 and a secondary secondary battery 20b, and a charging circuit 21 for charging the secondary battery 20. A discharge circuit 22 that boosts the battery voltage V6 output from the secondary battery 20 and makes the output voltage V3 substantially equal to the output voltage V3 from the DC-DC converter 31;
And a control circuit 23 that selectively performs various control operations to be described later.

The secondary battery 20 is usually composed of a plurality of battery cells. The battery voltage V6 is not particularly limited, but is desirably about 1/3 or more of the above-described DC voltage V3 to an equivalent voltage. The output performance and capacity of the secondary battery 20 are determined according to the design specifications as an uninterruptible power supply.

For example, in the power supply unit 11 for the computer device 10 of this embodiment, the maximum output power is 300 W, and the backup function of the secondary battery device 12
% For 6 minutes. DC-D
The output voltage V3 of the C converter 31 was 48 V, and the rated secondary battery voltage was 18 V. The secondary battery 20 was configured by connecting 15 nickel-metal hydride battery cells in series. 26mmφ × 60m due to backup function request
m, a nickel-metal hydride battery having a battery capacity of 5.8 Ah was prepared and used according to a method described later.

According to the present invention, the secondary battery 20 is provided in two systems of a primary secondary battery 20a and a secondary secondary battery 20b, and the primary secondary battery 20a has the above-mentioned specifications. , The secondary battery 20b is set to half the battery capacity of the main secondary battery 20a. Further, the main rechargeable battery 20a is used as a main power supply during a normal operation, and the sub rechargeable battery 20b operates in conjunction with the switching operation of the switching circuit 38 when the main rechargeable battery 20a described later is refreshed or fails. It is used as an auxiliary power supply.

The charging circuit 21 includes a DC-DC converter 3
By lowering the DC voltage V3 output from 1 and performing a charging operation at a predetermined timing based on control by the control circuit 23, the secondary battery 20 can be maintained in a state as close to a fully charged state as possible. I have.

The discharge circuit 22 boosts the battery voltage V6 of the secondary battery 20, and can generate a voltage substantially equal to the DC voltage V3 output from the DC-DC converter 31. Further, a CPU 35a, a memory 35b or an I / O 35c
The control of the control circuit 23 in accordance with the magnitude of the power supplied to the load 35 enables the control of the supplied power.

The control circuit 23 uses a microprocessor as an arithmetic element and operates according to a program. The control circuit 23 controls the charging circuit 21 and the discharging circuit 22 in the power supply unit 11 in response to inputs from various sensors. By transmitting the signals Sb and Sc, a predetermined control operation is performed. at the same time,
Various signals Sd and Se related to battery management and operation are also exchanged with the CPU 35a that controls the entire computer device 10 via the I / O 35c, and the entire secondary battery device is controlled.

As sensors, a temperature sensor 40 for measuring the temperature Ta of the secondary battery 20, a charging current sensor 41 for measuring the charging current Ia, and a discharging current sensor 39 for measuring the discharging current Ib are additionally provided. Discharge voltage V
7 is provided. Signals from these sensors are input to the control circuit 23.

The charge / discharge amount and charge / discharge timing of the secondary battery 20 are controlled based on the signal output from the sensor, and the detected charge / discharge currents Ia and Ib are integrated, whereby the secondary battery 20 is charged. The charge remaining amount of the battery can be grasped in real time.

Further, the current Ic flowing from the DC-DC converter 31 to the load 35 can be detected by the load current sensor 42. In this embodiment, the detection and control of the supplied power are substantially performed by detecting the magnitude of the load current Ic using the load current sensor 42. Alternatively, it may be detected.

Further, by inputting the output voltage V2 from the AC-DC converter 30 or a detection processing signal thereof as an input signal Sa, the commercial AC power supply 1
It is possible to detect whether or not up to the C converter 30 is operating normally. Various control operations in the control circuit 23 described below are performed using these signal inputs.

Here, the power supply unit 11 performs substantially the same operation as the uninterruptible power supply backed up by the secondary battery 20 as described above. Alternatively, there are various operation modes utilizing the charging and discharging of the secondary battery 20. The operation of the most versatile power supply unit 11 is shown in FIG.

The "stop mode" in which the computer device 10 is completely stopped, the "AC mode" in which only the AC power supply is operated, the "DC mode" in which only the DC power supply is operated, and the power supply by the AC power supply is insufficient due to the power supply mainly by the DC power supply. “Peak cut mode” to replenish the battery, “charging mode” to charge the secondary battery 20, “backup mode” to compensate the power supply with the DC power when the AC power is turned off, and the memory effect of the secondary battery 20. "Refresh mode" to eliminate
Exists.

As will be described in more detail below, the amount of power supplied to the load 35, the remaining charge and the number of times of charging and discharging of the secondary battery 20, or the AC input state, that is, whether or not there is a power failure or equipment failure, will be described in more detail below. , And automatically operates according to the operation.

Here, the "stop mode" is set regardless of the supply of the commercial AC power supply 1 to the power supply unit 11.
Is forcibly turned off and the operation of the computer device 10 is completely stopped.

This state is entered when the main switch of the computer device 10 is manually turned off, the outlet is disconnected, and the supply of the commercial AC power supply 1 is cut off. The power supply of the commercial AC power supply 1 is interrupted or the AC-DC converter 3
During the period in which the secondary battery 20 is in the backup mode by stopping for some reason such as the failure of the secondary battery 0, the remaining capacity of the secondary battery 20 further decreases to the lower limit capacity C.
0 is detected, the secondary battery 2
This is a case where the CPU 35a performs a predetermined shutdown operation using the remaining capacity of zero.

Next, in the "AC mode", the commercial AC power supply 1 is connected to the power supply section 11, the AC-DC converter 30 and the DC-DC converter 31 are on, and the remaining capacity of the secondary battery 20 is, for example, If the remaining power exceeds the lower limit capacity C1 set to 50% at the time of full charge and the power supply amount to the load 35 is in the middle range of not less than the preset lower limit power P1 and not more than the upper limit power P2, The charge / discharge operation for the secondary battery 20 is not performed, and power is supplied to the load 35 exclusively from the commercial AC power supply 1.

Further, entering the “peak cut mode”
This is a case where the power supplied to the load 35 further enters a large area exceeding the upper limit power P2 in a state where the remaining capacity of the secondary battery 20 exceeds the lower limit capacity C1 described above.

That is, even when power is being supplied from the AC-DC conversion circuit 29 to the load 35, the upper limit set power P2
That the power was supplied above the load current sensor 42.
Is detected by the discharge circuit 22 so that the excess power is supplied from the secondary battery 20 side.
By controlling the amount of discharge current of the AC-DC conversion circuit 29, the amount of power supplied from the AC-DC
Is supplied from the side of the secondary battery 20 while maintaining the value.

However, if the capacity of the secondary battery 20 falls below the lower limit capacity C1 or the power supplied to the load 35 falls below the upper limit power P2 during the discharge, the discharge from the secondary battery 20 is stopped and the commercial AC power supply is stopped. The operation returns to the “AC mode” in which power is supplied only from the “1”.

The "DC mode" is entered when the remaining capacity of the secondary battery 20 exceeds the lower limit capacity C1, and the power supplied to the load 35 is lower than the lower limit capacity, contrary to the peak cut mode described above. This is the case where the load current sensor 42 detects that the power has dropped below the power P1.

In this mode, for example, the operation of the AC-DC converter 30 is stopped and the DC-DC converter 3
The power supply to the load 35 is limited exclusively to the secondary battery 20 by stopping the output from the power supply 1 and operating the discharge circuit 22 at the same time.

However, even in this case, if the remaining capacity falls below the lower limit capacity C1 or the power supply to the load 35 exceeds the lower limit power P1 during power supply by the secondary battery 20, the AC-DC conversion circuit 29 To return to the “AC mode”.

The "charging mode" is in the "AC mode" described above, and the remaining capacity of the secondary battery 20 is larger than the lower limit capacity C1 and is equal to the upper limit capacity C such as the capacity at full charge.
This is performed when it is detected that the voltage falls below a predetermined capacity C2 within a range smaller than 3, and the sum of the power supplied to the load 35 and the power consumed for charging is further reduced. Current control in the charging circuit 21 is performed so as not to exceed the upper limit power P2. Then, when the capacity of the secondary battery 20 reaches the upper limit capacity C3, the charging circuit 21 is stopped to return to the “AC mode”.

In the “backup mode”, the power supply unit 1
1 that the input of the commercial AC voltage V1 to the AC power supply 1 or the function of the AC-DC converter 30 has been stopped.
When the mode is entered when the detection is made by the C signal Sa and the remaining capacity of the secondary battery 20 at that time exceeds the minimum lower limit capacity C0, the power supply from the secondary battery 20 to the load 35 is continued. When the AC power supply 1 returns, the operation returns to the “AC mode”.

However, when the remaining capacity of the secondary battery 20 is lower than the minimum lower limit capacity C0, a predetermined shutdown operation for the computer device 10 is automatically performed to perform a stop operation, and the "stop mode" is performed. Move on to The minimum lower limit capacity C0 does not adversely affect the computer device 10 and the system to which the computer device 10 is connected. For example, the power required to normally stop the computer device 10 while preventing data destruction. Is the capacity of the secondary battery.

The present invention has a feature in the configuration of the "refresh mode". This mode is used in conjunction with the rechargeable battery 20 being used for a set time or performing a set number of charge / discharge operations. to go into.

For example, when the "refresh mode" is entered during a period in which power is supplied to the load 35 using the main secondary battery 20a, the terminal voltage of the main secondary battery 20a becomes, for example, 1.0 V / cell. Until the set voltage is reached, the “peak mode” or the “DC mode” is used without entering the “charge mode”, or only the discharging to the load 35 is continued for the purpose of discharging only.

When the output voltage from the main rechargeable battery 20a falls below the set voltage, the switching circuit is switched to connect the main rechargeable battery 20a to the charging circuit 21 and start charging, while the discharging circuit 22 supplies the sub-battery. By connecting the secondary battery 20b, the power supply to the load 35 is
Cover from the 0b side. When the charging of the main secondary battery 20a is completed and the battery is fully charged, the power supply source from the secondary battery device 12 returns to the side of the main secondary battery 20a, and the above-described steady-state operation is continued. The battery 20b is charged,
When it is fully charged, it returns to the standby state.

When an abnormality of the main rechargeable battery 20a is detected other than in the refresh mode, the main rechargeable battery 20a is disconnected by the switching circuit 38 and the sub rechargeable battery 20b is connected to the main power supply source. At the same time, a predetermined warning is issued and the abnormality of the secondary battery 20 is displayed.

As described above, the capacity of the main rechargeable battery 20a and the capacity of the sub rechargeable battery 20b are set to be different from each other, so that the functions used during the normal operation and the auxiliary ones are not shared, but are the same. A plurality of capacities may be provided, and each rechargeable battery may be switched and used at appropriate times.

When 10% charge / discharge is repeated 100 times for the main secondary battery 20a with the remaining charge being 50%, the discharge voltage of the secondary battery 20a is reduced by the number of repetitions due to the memory effect. Decreases with increase. Due to the nature of this device, the secondary battery 20 must always maintain a capacity that can back up the working communication and information equipment, so if the secondary battery 20 is a single system, the stored capacity is completely discharged. It will not be done. For this reason, the voltage drop due to the memory effect is likely to contribute to the battery life.

Therefore, when the secondary battery 20a, whose voltage has been reduced due to the memory effect, is discharged once to 1.0 V / cell and then charged to a full charge state, this one discharge causes
It was confirmed that the voltage drop due to the memory effect was almost completely eliminated. This power supply device is, of course, also effective in an uninterruptible power supply device that does not have a function of supplying a part of the power during peak hours and supplies power only during a power failure.

[0048]

As described above, according to the present invention, the rechargeable battery 20 that partially covers the power during the power outage and during the peak is used as the main rechargeable battery 20.
a and the secondary battery 20b, the secondary battery 20b can be used for power supply instead of the main secondary battery 20a even during the refreshing of the main secondary battery 20a. The memory effect can be refreshed periodically or at every predetermined use value without impairing the power supply function of the battery 20.

Further, by using two systems of the secondary battery 20, an effect of drastically reducing the occurrence of backup failure due to battery abnormality or the like can be obtained. Further, in the case of a single system, after the secondary battery 20 is discharged due to a power outage or the like, a part of the power during charging and during peak time is to be supplied by the present device until a predetermined amount of electricity is charged. However, in the case of two systems, the secondary rechargeable battery 20b covers the period until the main rechargeable battery 20a is charged with a predetermined amount of electricity, so that the inoperable period of the present apparatus can be reduced. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a basic configuration of a power supply device according to the present invention.

FIG. 2 is a block diagram schematically showing an example in which a power supply device according to the present invention is implemented in a power supply unit in a computer device for a server.

FIG. 3 is a state transition diagram illustrating a relationship between operation modes provided in a power supply unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commercial AC power supply 2 Main power supply part 3 Auxiliary power supply part 4 Power supply device 5 Charge / discharge means 6 Battery capacity detection means 7 Control means 8 Communication / information equipment 9 Switching means 10 Computer device 11 Power supply unit 12 Secondary battery device 20 Secondary battery Reference Signs List 20a main secondary battery 20b sub-secondary battery 21 charging circuit 22 discharging circuit 23 control circuit 29 AC-DC conversion circuit 30 AC-DC converter 31 DC-DC converter 32 DC-DC converter 33 VRM 35 load 35a CPU 35b memory 35c I / O 38 Switching circuit 39 Discharge current sensor 40 Temperature sensor 41 Charge current sensor 42 Load current sensor

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Masato Isogai 1-1-88 Ushitora, Ibaraki-shi, Osaka F-term in Hitachi Maxell, Ltd. (Reference) 5G003 AA01 BA04 CA01 CA12 CB08 DA07 DA15 GB03 GC05 5G015 FA04 GB03 HA02 HA03 HA15 JA04 JA32 JA34 JA35 JA53 JA55 JA58 5H030 AA00 AS03 BB09 DD20 FF44

Claims (6)

[Claims] 1. A main power supply unit for converting commercial AC power into DC power to supply power to a load, and a secondary battery as a power supply source, wherein the power is supplied to the load instead of or in addition to the main power supply unit. A power supply unit integrally provided with an auxiliary power supply unit capable of supplying power, wherein a plurality of sets of the secondary batteries are operated in conjunction with each other and independently chargeable / dischargeable. Power supply. 2. The auxiliary power supply section includes: a charging / discharging unit for a secondary battery; a switching unit for switching a secondary battery charged / discharged by the charging / discharging unit; a battery capacity detecting unit for the secondary battery; Control means for regulating a charge / discharge amount and a charge / discharge timing in the charge / discharge means, wherein the control means performs a predetermined control operation based on a remaining capacity of the secondary battery and a required power amount on a load side. The power supply device according to claim 1, wherein: 3. The secondary battery has two sets of a main secondary battery and a sub-rechargeable battery, and the secondary secondary battery has a smaller battery capacity than the main secondary battery. Item 3. The power supply device according to item 1 or 2. 4. The battery according to claim 1, wherein the secondary battery is forcibly discharged to a refreshable predetermined voltage when a preset condition is reached.
The power supply device according to any one of claims 1 to 3. 5. The power supply device according to claim 1, wherein the power supply device is integrated in a communication / information device. 6. The power supply device according to claim 1, wherein the secondary battery is a nickel metal hydride battery or a nickel cadmium battery.