JP2831743B2 - Power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a power supply device capable of supplying stable output power even for a short-time power failure of an input AC power supply and the like, The present invention relates to a power supply device having a function of diagnosing the capacity of a storage battery when the storage battery is used as a part of the device and an automatic equalization charging function.

(Prior Art) As an example of a power supply device similar to the present invention, a conventional technology will be described with reference to a known uninterruptible power supply device. For the uninterruptible power supply, see Toshiba Review Vol. 42 No. 11 (November 1987) P.P877
Since these are introduced in various documents such as 880 to 880, and their functions and operation outlines are publicly known, here, using FIG. 4 and FIG. explain.

In FIG. 4, 10 is an input AC power supply, 11 is an inverter device, 12 is a rectifier, 13 is a DC filter capacitor, 14 is an inverter, 15 is an inverter transformer, 16 is an AC filter capacitor, 17 is a load, and 18 is a storage battery. is there.

In the configuration of FIG. 4, when the input AC power supply 10 is normal, the AC power is exchanged for DC power by the rectifier 12 in the inverter device 11, and smoothed by the DC filter capacitor 13,
The DC power is supplied to the inverter 14 and the charging current is supplied to the storage battery 18. The inverter 14 converts the smoothed DC power into AC power, and supplies AC power to the load 17 via the inverter transformer 15. At this time the inverter
In step 14, the voltage and frequency of the AC power supplied to the load 17 are controlled to predetermined values by employing the well-known PWM control, so that stable AC power can be supplied. The AC filter capacitor 16 is provided for absorbing the ripple of the AC power supplied at this time.

Further, when the input AC power supply 10 experiences a short-term power failure, the DC power is discharged from the storage battery 18, and similarly stable AC power can be supplied to the load 17 via the inverter 14. Storage battery 18
The uninterruptible power supply combining the inverter and the inverter 11 operates as described above, so that even if the input AC power supply 10 experiences a short power outage, a predetermined time (for example, 10 minutes) determined by the capacity of the storage battery 18 is obtained.
Stable AC power can be supplied to the load 17 only for 30 minutes.

If a long power outage of the input AC power supply 10 is expected,
In the case where the load 17 is a public computer load or the like, an in-house power generation facility is further provided as a backup facility, and the AC power can be supplied from the in-house power generation facility via the inverter device 11 by switching to the input AC power supply 10. However, during this power supply switching time, the storage battery 18 must be discharged to secure power supply to the load 17.

FIG. 5 shows waveforms for explaining the operation of the storage battery 18 in the uninterruptible power supply of FIG. 4 as described above.
10, (b) is the voltage of the storage battery 18, (c) is the storage battery 18
Is illustrated. When the input AC power supply 10 at time t ₁ is a power failure the storage battery 18 starts to discharge, the voltage of the battery 18 when discharged until time t ₂ becomes the final discharge voltage (allowable minimum voltage), this for the protection of the battery 18 It is necessary to stop the discharge of the storage battery 18 by detecting the voltage level.

Storage battery so that from time t ₁ in the uninterruptible power supply to the period of time t ₂ and systematically required outage compensation time
18 capacities are selected. Therefore, even if there is a power failure of the input AC power supply 10 within a predetermined time, an uninterruptible power supply device that can back up this power by the storage battery 18 and continue to supply stable power to the load 17 is widely used.

(Problems to be Solved by the Invention) As described above, the uninterruptible power supply can continuously supply stable AC power to the load within a predetermined power outage time. The use of an uninterruptible power supply as a power supply for a large computer or the like that requires the use has been increasing very much.

However, the backup time for a power failure of the input AC power supply 10 in the uninterruptible power supply is governed by the capacity of the storage battery 18.
Initially, the capacity of the storage battery 18 is selected based on the system capacity. However, the storage battery 18 tends to deteriorate over time, and has a characteristic that the discharge capacity changes depending on the operating temperature and the like.

As a result, with the conventional power supply, the input AC power
The storage battery 18 was discharged at the time of the power failure of 10, and as a result, it was determined whether the storage battery 18 could cover the power failure compensation time required by the system. Therefore, even if the capacity of the storage battery 18 tends to deteriorate, if the trouble of the shortage of the power failure compensation time does not actually occur, this will not be known, and if a trouble occurs, an unspecified number of users of the load 18 will cause great trouble ( For example, the power supply device of the related art has a drawback that the user always feels uneasy as a power supply device that requires high reliability because the online system of the bank is stopped or the counter operation of the aircraft is stopped. .

The present invention has been made in view of the above-mentioned drawbacks of the conventional power supply device, and can diagnose the discharge capacity of the storage battery when the input AC power supply is normal. The purpose of the present invention is to provide a power supply device that performs the following.

[Configuration of the invention]

(Means for Solving the Problems) According to the present invention, in the configuration shown in FIG. 1 or FIG.
A circuit for observing the discharge current of 18 and the voltage change at the time of discharge is provided, and when the input AC power supply 10 is in a normal state, the inverter device
10 rectifier 12 is stopped for a predetermined time or rectifier 12 and storage battery 18
, And the storage battery 18 is discharged. Observe the discharge current and voltage change of the storage battery 18 during this discharge, diagnose the capacity of the storage battery 18 from the discharge charge and the voltage change,
Based on the diagnosis result, the storage battery 18 is automatically charged equally.

Such a diagnosis of the storage battery 18 and automatic equal charging,
When the input power supply 10 is normal, for example, by performing the above method continuously and periodically, the power failure backup capability of the battery with respect to the load of the storage battery 18 can be prevented from lowering below a predetermined level.

(Operation) The capacity of the storage battery 18 is generally “discharge current × discharge time, Ah”
Defined by Therefore, as described above, the storage battery 18 is discharged for a predetermined time, and the amount of discharge Ah and the voltage of the storage battery 18 during this period are observed. Can be grasped about what percentage of the initial value. Therefore, the backup capacity of the power storage 18 with respect to the load 17 can be diagnosed from the relationship between the discharge amount and the remaining capacity. The uniform charging mode and the uniform charging time are determined based on the diagnosis result, the equal charging is automatically performed, and the power supply stop due to the decrease in the backup capability can be prevented.

(Embodiment) An embodiment of the present invention is shown in FIG. In this figure,
The circuit components denoted by the same reference numerals as those in FIG. 4 have the same functions, and thus description thereof will be omitted. As circuit components added in FIG. 1, 19 is a current detector, 20 is a voltage detector, and 21 is a remaining capacity detector of the storage battery.

In FIG. 1, when the AC power of the input AC power supply 10 is supplied to the load 17 through the inverter device 11, the storage battery 18
In order to determine the capacity of the rectifier 12, the rectifier 12 is stopped within a predetermined time, and the electric charge of the storage battery 18 is supplied to the load 17 via the inverter 14. Here, for simplicity of explanation, an example in which the rectifier 12 is stopped and power is supplied only from the storage battery 18 is shown.
Power may be supplied from both the battery 12 and the storage battery 18, thereby discharging the storage battery. FIG. 2 shows the discharge current and voltage waveform of the storage battery at this time. FIG. 2A shows the voltage waveform of the storage battery 18, and FIG. 2B shows the discharge current. The rectifier 12 is stopped at time t _1, again re-operate the rectifier 12 at time t _4.

Voltage of from time t ₁ to time t ₃ battery 18 is suddenly but recovered then gradually reduced in relation of the internal impedance of the battery 18, FIG. 2 as a whole as the voltage discharge of the battery 18 progresses (a As shown in ()), the voltage waveform of the storage battery 18 decreases.

The discharge current of the storage battery 18 shown in FIG.
Detected at 19 and input to the remaining capacity detector 21. The voltage waveform is also detected by the voltage detector 20 and input to the remaining capacity detector 21. In remaining capacity detector 21, the discharge charge the storage battery 18 is discharged from time t ₁ to time t ₄ is detected by Ah, the voltage detector to the initial design time voltage and time t ₄ of the Ah discharge time of the battery 18 20 By comparing the voltages detected in the above, the capacity of the storage battery 18 can be easily determined.

The remaining capacity of the storage battery 18 after the predetermined Ah discharge can be calculated as a change in the battery voltage depending on the type of the storage battery, as is well known. Detailed remaining capacity can be detected,
It is possible to grasp the deterioration of the storage battery 18 due to deterioration over time and the installation environment. The detection of the remaining capacity can be easily realized by using a microcomputer or the like.
As a means to grasp the 18 capability of fixed time to time t ₄ to time t ₁ of FIG. 2, the detection voltage in the original design value voltage and time t ₄ due to discharge charge within this time simply level Only by comparing, it is possible to grasp the state of the capacity reduction of the storage battery 18 with respect to the initial design value.

The backup capacity of the storage battery 18 with respect to the load is diagnosed by the above method, and based on the diagnosis result, the rectifier 12 is controlled by the rectifier controller 22 to automatically perform equal charging according to the capacity of the storage battery 18 and the backup capacity of the storage battery 18. Can be prevented from decreasing.

FIG. 3 shows an example of another embodiment of the present invention. In this figure
Reference numeral 23 denotes a charger 24 of the storage battery 18, and other circuit components are the same as the circuit components of FIG.
In FIG. 3, two inverters 10 are connected to an input AC power supply 10, and the outputs of the inverters 10 are connected in parallel to load 17
In this case, the storage battery 18 is provided in common to the two inverter devices 11, so that a dedicated charger 23 and a charge controller 25 for the storage battery 18 are provided, and the rectifier 12 of the inverter device 11 is provided. The diode 24 is added for the purpose of avoiding mutual interference. In the uninterruptible power supply device configured as shown in FIG. 3, when diagnosing the capacity of the storage battery 18, the two rectifiers 12 may be stopped simultaneously, and only one of the two rectifiers 12 may be stopped. Thus, the performance of the storage battery 18 may be diagnosed. The present invention is characterized in that the capacity of the storage battery 18 is diagnosed by supplying a part of the power supplied to the load 17 from the storage battery 18 when the input AC power supply 10 is normal, and in particular, whether one rectifier 12 is stopped. It is not limited in the present invention whether two units are stopped simultaneously.

1 and 3, it is described that the rectifier 12 is stopped and the storage battery 18 is discharged. However, at least a part of the power supplied to the load 17 by operating the storage battery 18 and the rectifier 12 in parallel is stored in the storage battery 18. It is apparent that the effect of the present invention can be similarly obtained as a method of further discharging and detecting the remaining capacity of the storage battery 18 by the remaining capacity detector 21 at that time.

Although the present invention has been described with reference to an uninterruptible power supply, the internal configuration of the power supply is not particularly limited in the present invention, and a storage battery is used so that power can be supplied for a predetermined time during a blackout of an input AC power supply. Any power supply device can be used.

It is apparent that various modifications can be made without departing from the scope of the present invention.

〔The invention's effect〕

A storage battery connected to the DC circuit of a power supply that supplies stable output power to a load even when the input AC power supply fails is generally discharged by discharging its charge when the input AC power supply that requires the storage battery function is really required. Since the expected storage battery capacity was determined, if the storage battery capacity had deteriorated, stable power could not be supplied to the load, causing a power outage accident on the load side and the danger of expanding the accident. was there.

As described above, a power supply device that is backed up by a storage battery is required to increase reliability in order to supply power to an important load as an uninterruptible power supply device. However, it is apparent that the following effects can be obtained according to the present invention. is there.

(1) By diagnosing the backup capacity of the storage battery with respect to the load and automatically performing the equal charge, a predetermined level of the backup capacity can be maintained, so that the power can be reliably supplied to the load for a predetermined time during a power failure.

(2) Since uniform charging is performed based on the result of the capacity diagnosis of the storage battery, unnecessary charging or insufficient charging can be eliminated, and efficient charging can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the function of the present invention, FIG. 3 is a block diagram showing another embodiment of the present invention, and FIG. FIG. 5 is a block diagram showing an embodiment of the technology, and FIG. 5 is a diagram for explaining the characteristics of the storage battery of FIG. 10 Input AC power supply 11 Inverter 12 Rectifier 13 DC filter capacitor 14 Inverter 15 Inverter transformer 16 AC filter capacitor 17 Load 18 Battery 19 …… Current detector, 20 …… Voltage detector 21 …… Remaining capacity detector, 22 …… Rectifier controller 23 …… Charger, 24 …… Diode 15 …… Charge controller

Claims (2)

(57) [Claims] When an input AC power supply is converted into electric power by a power supply and supplied to a load, the load is supplied to the load via a DC circuit of the power supply even if the input AC power is interrupted for a short time. Is supplied, and a stable power can be continuously supplied to the load even during the power failure. The input AC power supply normally supplies at least a part of the power supplied to the load inside the power supply device in a normal state. Is supplied from the storage battery for a predetermined time, the remaining capacity of the storage battery and the capacity of the storage battery are diagnosed based on the discharged charge amount of the storage battery within this predetermined time and the storage battery voltage after discharging, and the result is automatically equalized according to the result. A power supply device characterized by performing: 2. When the power of an input AC power supply is converted into power by a power supply and supplied to a load, even if the input AC power supply is interrupted for a short time, the load is supplied to the load via a DC circuit of the power supply from a storage battery. Is supplied, and a stable power can be continuously supplied to the load even at the time of the power failure. The input AC power supply supplies power to the load inside the power supply at normal time for a predetermined time. Supply from the storage battery,
A power supply device characterized in that the remaining capacity of the storage battery and the capacity of the storage battery are diagnosed from the storage battery voltage after the predetermined time, and the equalization is automatically performed based on the result.