JP3433469B2 - Uninterruptible power system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is connected to a device (hereinafter referred to as "computer device, etc.") operated by an external power supply, such as a computer device or a communication device. The present invention relates to an uninterruptible power supply that supplies power to a device in place of a power supply when a power supply trouble occurs. 2. Description of the Related Art In recent years, when a computer device or the like has become abnormal due to a trouble of an external power supply such as a power failure or a voltage change, an uninterruptible power supply is connected to protect data during processing. ing. [0003] A conventional uninterruptible power supply detects an abnormality in the event of a power supply failure, and keeps a computer until a battery such as a lead battery built into the uninterruptible power supply drops to a predetermined constant voltage in place of the power supply. By supplying power to the apparatus and the like, the computer apparatus and the like are prevented from being stopped during data processing and the data being processed is not lost. However, in the conventional uninterruptible power supply described above, the discharge end voltage of the battery is not constant depending on the discharge current, and in order to prevent overdischarge as the discharge current decreases, The end voltage needs to be set high. Therefore, means for varying the set voltage for comparing and detecting the battery terminal voltage according to the discharge current value is required, and there has been a problem that the configuration becomes complicated and the device becomes expensive. When the discharge end voltage is set to a high value in accordance with the case where the discharge current is small, when the load capacity of the uninterruptible power supply is large and the discharge current is large, the discharge time of the battery is longer than the time that can be taken out. There is a problem that the backup time becomes short because the discharge time becomes short and the discharge capability cannot be sufficiently obtained. Accordingly, the present invention has been made in view of such a conventional problem, and when the load capacity is large,
It is an object of the present invention to provide an excellent uninterruptible power supply in which the discharge time of a battery is sufficiently extracted to ensure the maximum backup time and the battery is not overdischarged even under a light load. In order to achieve the above object, according to the present invention, when a power failure occurs or a power failure occurs due to a voltage change, the inverter converts the DC power of a battery as a backup power supply from the AC power of an external power supply. An uninterruptible power supply device that switches to AC power converted via the power supply and supplies the load device with the voltage, a voltage detection unit that detects a terminal voltage of the battery, and a voltage detection unit that is set to be larger than a terminal voltage of the battery and a discharge end voltage of the battery. A plurality of predetermined voltages, and when the battery terminal voltage falls below the plurality of predetermined voltages, a voltage comparison means for generating a first control signal; and a timer set according to a load current capacity. Free time
And Control, before the elapsed time from the start of the supply of backup power from the battery corresponding to a plurality of load current
A timer management means for generating a second control signal when the timer set time is exceeded, and a backup power supply for stopping supply of the backup power when receiving the first or second control signal. The power supply system further includes a stop unit, and an output switching unit that switches the external power supply to a backup power supply based on a detection signal supplied from the power failure detection unit and indicating an abnormal state of the external power supply. Therefore, according to the present invention, the external power supply is detected by the power failure detection unit.
When a detection signal indicating an abnormal state is supplied, the output switching unit
While switching the external power supply to the backup power supply, the terminal voltage of the battery, that is, the output voltage, is detected, and the terminal voltage of the battery is compared with a predetermined voltage set to be higher than the discharge end voltage of the battery, and at the same time, the start of the backup operation by the battery is detected. By measuring the backup power supply time and comparing the elapsed time with a set time which is a backup supply limit time corresponding to a plurality of load currents, when the battery voltage falls below the comparison voltage, or If the supply time exceeds the comparison time limit, the backup operation of the uninterruptible power supply is stopped. An embodiment of the uninterruptible power supply according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an uninterruptible power supply according to the present invention. In FIG. 1, an uninterruptible power supply 1 supplies power to a load device (computer device or the like) 2 from a commercial power supply P as an external power supply or a built-in battery 1g. The uninterruptible power supply 1 includes the following components. That is, a charging unit 1a for charging the battery 1g from the commercial power supply P, a battery cutoff unit (backup power supply stopping means) 1b for cutting off the current of the backup power supply from the battery 1g according to a control signal described later,
An inverter unit 1c for generating a power supply voltage to the load device 2 by power supply from the battery 1g; an output switching unit 1d for switching between a commercial power supply P connected to the contact 1d1 and an inverter unit 1c connected to the contact 1d2; The output switching unit 1d and the inverter unit 1
a power failure detection unit (power supply monitoring means) 1f for controlling the power supply c, a timer management unit for starting operation upon receiving a detection signal indicating an abnormal state from the power failure detection unit 1f, and for turning off the battery cutoff unit 1b for a preset time. (Timer managing means) 1e, a voltage detecting section (voltage detecting means) 1h for detecting a battery voltage,
A voltage comparison unit (voltage comparison unit) 1i that compares the output of the voltage detection unit 1h with a preset voltage and turns off the battery cut-off unit 1b when the detection voltage becomes equal to or less than a set value. The signal lines of the first and second control signals A and B input from the timer management unit 1e and the voltage comparison unit 1i to the battery cutoff unit 1b have a configuration such as a wired OR, and the battery cutoff unit 1b Is turned off regardless of which control signal is received. Next, backup processing in the event of a power failure by the uninterruptible power supply 1 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a flowchart showing the operation of the backup process in the event of a power failure of the uninterruptible power supply in FIG. First, in a normal state, power from the commercial power supply P is supplied from the commercial power supply P to the load device 2 via the contact 1d1 of the output switching unit 1d, and at the same time, the battery 1g is in a charging operation state by the charging unit 1a. . Further, the inverter unit 1c is stopped by a signal from the power failure detection unit 1f, and the load device 2 is in commercial power supply operation (step S1). The power failure detection section 1f monitors the commercial power supply P, and determines whether a power failure such as a power failure or a voltage change has occurred (step S2).
When a power failure occurs, a detection signal indicating an abnormal state is output from the power failure detection unit 1f, and the output switching unit 1d
Is switched to the contact 1d2 side, and at the same time, the inverter unit 1c
But to start. Then, the backup operation from the inverter unit 1c starts, and the supply of the backup power from the battery 1g to the load device 2 starts (step S3).
At the same time, the timer management unit 1e is activated by a signal from the power failure detection unit 1f, and the timer count starts (step S4). That is, the elapsed time from the start of the backup power supply is measured by the timer management unit 1e. After the start of the backup operation, that is, after the operation of the load device 2 by the inverter unit 1c is started, the terminal voltage of the battery 1g is measured by the voltage detecting unit 1h, and the terminal voltage of the battery 1g is measured by the voltage comparing unit 1i. Are compared (step S5). Here, if the detected voltage is equal to or lower than the set voltage, the first control signal A for immediately turning off the battery cutoff unit 1b is issued, the current from the battery 1g to the inverter unit 1c is stopped, and the backup operation is stopped. (Step S9). On the other hand, if the detected voltage of the battery 1g is higher than the set voltage, the timeout of the timer management unit 1e is checked (step S6).
That is, if the elapsed time from the start of the backup operation has not reached the set time, the power failure detection unit 1f detects power recovery to determine whether or not the power failure state (power failure state) of the commercial power supply P is continuing (step S7). If the power failure state continues, the process proceeds to step S5. If the commercial power source P is restored, the backup operation is stopped, and the output switching unit 1d is switched to the commercial power source P to perform the normal commercial power operation. (Step S8), and then goes to Step S1. If the time-out has occurred in step S6, that is, if the elapsed time from the start of the backup operation has exceeded the set time, a second control signal B for immediately turning off the battery cutoff unit 1b is issued, and The current from the battery 1g to the inverter unit 1c is stopped, and the backup operation is stopped (step S9). FIG. 3 is a diagram showing the relationship between the discharge characteristics of the battery 1g, the set voltage value and the timer set time, and shows the case where there are three unit batteries (cells) and the case where there are six unit batteries. is there. In FIG. 3, a characteristic curve e1,
e2 and e3 indicate the discharge characteristics of the battery 1g, the discharge characteristic e1 is a large discharge current, the discharge characteristic e3 is a small discharge current, and the discharge characteristic e2 is a value between the discharge currents. Points c1, c2, and c3 are discharge characteristics e1, e, respectively.
2. This is the discharge end voltage on e3. If the battery is discharged below this voltage, it will be overdischarged and the life of the battery 1g will be shortened.
Note that the characteristic curve d is a characteristic curve of the discharge end voltage connecting the discharge end voltages c1, c2, and c3. In FIG. 3, the horizontal axis b 'is a set voltage value set in a conventional uninterruptible power supply having no timer management unit, and is a voltage value which does not cause overdischarge even at a light load (that is, discharge termination). (A value higher than the voltage c3). Therefore, for example, in the case of the discharge characteristic of the characteristic curve e1, the backup operation is stopped at the point of c1 ', and as described in the section of "Problems to be Solved by the Invention", Although it is large, that is, even though the battery 1g has a discharge capability, the discharge capability cannot be sufficiently taken out, and the dischargeable time is shortened. Therefore, in the present embodiment, a set voltage b lower than the conventional set voltage b 'is set, a timer set time a is determined, and when the discharge time reaches the timer set time a, the backup operation is stopped. Then, the discharge is stopped. With this configuration, in the case of the discharge characteristic of the characteristic curve e1, the time of the backup operation is extended to the point c1, and the operation range of the backup operation is as shown in FIG.
, The overdischarge at the time of light load is prevented, and when the discharge current is large, a long discharge time can be secured. Therefore, it is possible to sufficiently take out the discharging ability of the battery 1g. In this case, with respect to the point c0 in FIG. 3, when the set voltage b is used as a reference, the maximum of the timer set time a is the time of the point c0. The minimum value of b is the voltage value at point c0. That is, the point c0 needs to be set to a value larger than the value of the characteristic curve d of the discharge end voltage. In the uninterruptible power supply, it is required to secure a longer backup time when the load capacity is large. Therefore, the uninterruptible power supply of the present invention shown in the above embodiment has excellent effects. Become. [0021] In the above SL embodiment has a timer set time fixed, by changing the program, or with a time setting means such as a DIP switch, a configuration which allows the user to configure. Furthermore, it is also possible to adopt a configuration to control the timer setting freely in accordance with the capacity of the load current. As is apparent from the above embodiment, the present invention provides a first control signal when the battery terminal voltage falls below a predetermined voltage with respect to a plurality of predetermined voltages set to a low value. Or the timer set time automatically according to the load current capacity.
And the elapsed time from the start of the backup power supply from the battery corresponds to multiple load currents.
When the second control signal is received when the time exceeds the timer set time , the supply of the backup power is stopped, and when the load capacity is large, the discharge capacity of the battery is sufficiently extracted to maximize the backup time. while securing, because never since the battery is not over-discharged battery life is shortened even when the load is light, the onset
A single uninterruptible power supply with multiple
There is an effect that it can respond to loading equipment .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a configuration of an uninterruptible power supply according to the present invention. FIG. 2 is a flowchart showing an operation of a backup process when a power failure occurs in the uninterruptible power supply in FIG. 1; FIG. 3 is a diagram showing a relationship between a discharge characteristic of a battery, a set voltage value, and a timer set time in the present invention. [Description of Signs] 1 Uninterruptible power supply 2 Load device (computer device etc.) 1b Battery cutoff unit (backup power supply stop unit) 1c Inverter unit 1d Output switching unit 1e Timer management unit (timer management unit) 1f Power failure detection unit (power supply 1g Battery 1h Voltage detector (voltage detector) 1i Voltage comparator (voltage comparator) P Commercial power supply (external power supply)

Continuation of front page (56) References JP-A-58-157346 (JP, A) JP-A-59-122328 (JP, A) JP-A-62-272831 (JP, A) JP-A-1-74035 (JP) JP-A-3-93424 (JP, A) JP-A-4-372536 (JP, A) JP-A-5-199679 (JP, A) JP-A-5-207678 (JP, A) 55-51699 (JP, U) Japanese Utility Model Showa 61-2742 (JP, U) Japanese Utility Model Showa 62-11342 (JP, U) Japanese Utility Model Utility Model 1-25851 (JP, U) (58) Field surveyed (Int. H02H ⁷ /10-7/20 H02J 7/00-7/12 H02J 7/34-7/36 H02J 9/00-9/08

Claims (1)

(57) [Claims 1] When a power failure occurs due to a power failure or a voltage change, switching from AC power of an external power supply to AC power obtained by converting DC power of a battery as a backup power supply via an inverter. An uninterruptible power supply for supplying load equipment, comprising: voltage detecting means for detecting a terminal voltage of the battery; and comparing a plurality of predetermined voltages set to be higher than a terminal voltage of the battery and a discharge end voltage of the battery. When the battery terminal voltage falls below the plurality of predetermined voltages , the timer setting time is freely controlled in accordance with the voltage comparison means for generating the first control signal and the capacity of the load current.
Rolls, and the elapsed time from the start of supply of the backup power from the battery corresponds to a plurality of load currents.
A timer management means for generating a second control signal when the time exceeds the set time, and a backup power supply stop for stopping the supply of the backup power when receiving the first or second control signal And an output switching unit that switches the external power supply to a backup power supply based on a detection signal indicating an abnormal state of the external power supply supplied from the power failure detection unit.