JPH04140018A - Uninterruptible power supply and discharge termination detecting method - Google Patents

Abstract

PURPOSE:To prevent leakage of battery current and to detect discharge termination voltage reliably even in case of high battery voltage by providing means for feeding battery output to a charging power supply upon power interruption and means for detecting the discharge termination voltage of the charging power supply which operates with the battery output. CONSTITUTION:Upon power interruption, a power interruption occurrence signal has a significant value and a discharge circuit SW1 is turned ON. Consequently, power is fed from a battery 1 to a load and a charging circuit 2. Upon battery voltage drop to a discharge termination voltage level, a battery voltage detecting circuit 4a outputs a discharge termination detection signal. Upon receiving the discharge termination detection signal, an external unit makes a UPS signal ineffective thus opening the discharge circuit SW1. Consequently, discharge of battery 1 is stopped and the power supply is interrupted. According to the constitution, leakage of battery current is prevented and the discharge termination voltage can be detected reliably even in case of high battery voltage.

Description

[Detailed Description of the Invention] [Summary] This invention relates to an uninterruptible TT power supply device for continuing operation by supplying power from a commercial AC input power outage special battery, which prevents the occurrence of battery leakage current and .

The purpose of this project is to provide a high-multiplying, low-cost uninterruptible power supply that can reliably detect the end-of-discharge voltage even when the battery voltage is high. In an uninterruptible N power supply device comprising a charging power source having drooping characteristics and charging the battery from the charging power source via a diode, the output of the HN battery is supplied to the charging power source during a power outage. The battery includes a supply means, and a detection means for detecting that the output of the charging power supply operated by the output of the battery supplied through the supply means has reached the discharge end voltage.

[Industrial Application Field] The present invention is an uninterruptible II system that continues power supply by supplying power from a commercial AC input power outage special battery.
The present invention relates to power supplies, and particularly to improvements in means for detecting battery voltage during discharge.

In recent years, with the spread of electronic computers of various sizes, personal computers, facsimile machines, etc., damage caused by instantaneous interruptions in commercial power supplies and power outages has increased.

Therefore, uninterruptible power supplies are increasingly being used as a countermeasure against power outages. In reality, the market for uninterrupted II power supply equipment has been growing at an annual rate of more than 30% in recent years.

When introducing such an uninterruptible power supply, it was common to connect the uninterruptible power supply to the outside of the equipment, but at Kuuchika, it is built into the equipment from the beginning, so that it can be easily connected to the outside of the equipment to prevent momentary interruptions in commercial power supply or power outages. There are also emerging methods that attempt to reliably prevent the damage caused by such attacks.

Uninterruptible power supply equipment is usually a commercial power supply equipment (1)
At the same time, the battery inside the uninterruptible TFI device is charged, and when a power outage occurs, power is supplied from the internal battery. is expected to continue.

The battery used for this purpose is a rechargeable battery (referred to as a secondary battery J), but if the battery voltage drops below a certain specified value (discharge end voltage) due to discharge, the battery deteriorates and the battery May affect lifespan.

Therefore, it is necessary to monitor the battery voltage during discharging and to stop supplying power from the battery when the battery voltage drops to the end-of-discharge voltage due to discharging.

[Conventional technology]

FIG. 6 is a diagram showing a typical configuration of a conventional uninterruptible power supply device.

In the figure, 1 is a battery, 2 is a charging power source, 4a is a comparator, SWI and SW2 are switches, DID2 is a diode, and R1 and R2 are resistors.

As the battery 1, a rechargeable secondary battery is used.

Charging source 2 is fi# for charging battery 1
For example, it is composed of a Suinochinda regulator or the like.

This charging source 2 has overcurrent drooping characteristics as shown in FIG.

Furthermore, as shown in Fig. 3, charging amount #2 is such that when the battery 1 is almost empty immediately after charging starts, a large charging current tends to flow, so constant current charging is performed due to overcurrent droop. When charging progresses to a certain extent, the charging current drops below the overcurrent drop point, so constant voltage charging is performed.

The comparator 4a is composed of an operational amplifier, and is based on the voltage obtained by dividing the output voltage of the battery 1 by resistors R1 and R2.
1! The voltage is compared with the voltage Vref, and when the voltage divided by the resistors R1R2 becomes smaller than the reference voltage Vref, a discharge end detection signal is output.

Next, the operation of the uninterruptible IT source device having the above configuration will be explained.

Normally, power for charging is supplied from the input/output terminal T. This power is blocked by the diode D1 and is not directly supplied to the battery 1, but operates the IT source 2 for charging the battery 1 through the switch SW2. The output voltage of this charging power source 2 is applied to the battery 1 through diode D2.
is applied to the battery 1, thereby charging the battery 1.

During a power outage, power is not supplied from the input/output terminal T, and the battery 1 is discharged through the diode D1, the switch SWI, and the input/output terminal T, and power is supplied to the load. At this time, charging power supply 2 does not need to operate, so
Generally, the switch SW2 is opened. Furthermore, current does not flow from the battery 1 to the charging power source 2 due to the diode D2.

The end-of-discharge voltage is detected by detecting the positive electrode voltage of the battery 1. That is, the output voltage of the battery 1 is divided by the resistors R1 and R2, inputted to the comparator 4a, and compared with the reference voltage Vref.

When the battery voltage decreases to reach the end of discharge voltage, the output of the comparator 4a is inverted, and an end of discharge detection signal is output.

As a result, switch SWI is disconnected and battery 1
Discharge from the battery is stopped to prevent over-discharge.

However, in the above configuration, the resistance R
The battery 1 continues to be discharged little by little due to the leakage current flowing through R2. Therefore, if such a state is left for a long period of time, it is inevitable that the battery voltage will fall below the final discharge voltage.

If the resistors R1 and R2 are set to several tens of ohms or more, the leakage current will decrease, but it will become more susceptible to the effects of humidity, noise, etc.
Since it becomes difficult to detect the discharge end voltage, there is a limit to how much leakage current can be reduced.

As a solution to these drawbacks of conventional devices, the seventh
As shown in the figure, there is a device that uses an impedance converter 5 to detect the battery voltage.

This is the same as that described in FIG. 4, except that the output voltage of battery 1 is supplied to resistors R1 and R2 via impedance converter 5.

The impedance converter 5 is a circuit having characteristics of high input impedance and low output impedance, and thereby can reduce leakage current from the battery 1. As a specific example of the impedance converter 5, as shown in FIG. 8, an operational amplifier is often used in a voltage follower connection.

However, in this case, there is a problem that if the battery voltage is high, the component breakdown voltage of the operational amplifier is insufficient and it cannot be used. Further, if other impedance converters are used, there is a problem that the number of parts increases, reliability decreases, and costs increase.

[Problem to be solved by the invention]

In this way, a device that detects the end of discharge voltage by dividing the battery voltage with a resistor and comparing it with a reference voltage,
Battery leakage current occurs after discharging has stopped or when the uninterruptible power supply is not in use, and it is unavoidable that the battery will continue discharging.

In order to avoid this, the end-of-discharge voltage is detected by using an impedance converter to extract the battery voltage, dividing it with a resistor, and comparing it with a reference voltage. Impedance converters that can withstand high voltage require an increased number of parts,
This method has the drawbacks of low reliability and high cost.

The present invention has been made in view of the above circumstances, and is a highly reliable system that prevents the occurrence of battery leakage current and can reliably detect the end-of-discharge voltage even when the battery voltage is high.
The purpose is to provide a low-cost uninterruptible power supply device.

[Means to solve the problem]

FIG. 1 is a diagram for explaining the principle of the present invention. That is, in order to achieve the above object, the uninterruptible power supply device of the present invention includes a chargeable and dischargeable battery 1 and a charging source 2 having a constant drooping characteristic for charging the battery 1. , an uninterruptible power supply device configured to charge the battery 1 from the charging power source 2 via the diode D2, comprising: supply means 3 for supplying the output of the battery 1 to the charging power source 2 during a power outage; Detection means 4 is provided for detecting that the output of the charging power source 2 operated by the output of the battery 1 supplied via means 3 has reached the discharge end voltage.

[Effect]

Normally, power is supplied from the input/output terminal T for charging. This power is supplied to the diode D provided in the supply means 3.
1 and is not directly supplied to battery 1, but is supplied to charge amount #2 of hunterly 1. This drives the charging source 2.

The output voltage of the charging amount a2 is applied to the battery 1 through the diode D2, thereby charging the battery 1.

Here, the charging W f12 is as shown in FIG.
As shown in Fig. 3, when battery 1 is almost empty, a large charge W'W current tries to flow, so constant current charging is performed due to excessive tfL drooping, and the As wide charging progresses, the charging current drops below the overcurrent drop point, so constant voltage charging is performed.

During a power outage, power is not supplied from the input/output terminal T, and the discharge from the battery-1 flows through the diode D1 and the switch S.
This is done through WI. At this time, since there is nothing on the path leading to the charging power source 2 that obstructs the power supply, the charging power source 2 continues to operate receiving the output from the battery 1.

Note that the diode D2 prevents the current from flowing from the battery 1 to the charging source 2.

The discharge end voltage during discharging can be detected by dividing the output voltage of the charging source 2 by resistors R1 and R2 constituting the detection means 4, inputting the divided voltage to the comparator 4a, and comparing it with the reference voltage Vref. It will be done.

When a power outage occurs, the load (input/output terminal T) is removed from battery 1.
When power is supplied to the charging TFI 2, the charging power source 2 does not stop operating, so that the charging power source 2 also supplies power to the load.

At this time, the charging source 2 has overcurrent drooping characteristics as shown in FIG. 2, so the output drops to ``battery voltage + forward voltage of diode D2''. Therefore, by dividing this voltage by R1 and R2 and detecting it, the battery voltage can be monitored.

According to such a configuration, after discharging is stopped or when the uninterruptible power supply is not used, the diode D2 blocks the flow of current toward the charging power source, so that the output of the battery 1 becomes a resistor. There is no leakage through R1 and R2, and even if the battery is left unused for a long period of time, the battery voltage will not drop below the final discharge voltage.

Furthermore, since an impedance converter or the like is not required, the number of parts is reduced, and high reliability and low cost can be realized.

Furthermore, even when the battery voltage is high, it is possible to divide the voltage using R1R2, so a comparator for detecting the end-of-discharge voltage can be configured using an element with a low withstand voltage.

[Examples] Examples of the present invention will be described below with reference to the drawings.

FIG. 4 is a block diagram showing the configuration of an embodiment of the present invention. In the drawings, parts that are the same as or equivalent to those shown in FIG. 1 will be described with the same reference numerals.

In the figure, 10 is a board, and various hardware constituting an uninterruptible power supply (UPS) is mounted on this board 10.

Two connectors CNICN2 are provided at the ends of this board 10.

The connector CNI is used as the input/output terminal T shown in Fig. 1, and is connected to the "charging +31VJ line" and "
0■" line is provided.

The "Charging +31■" line is normally supplied with a direct current voltage of +31 VDC for charging from the outside, and in the event of a power outage, a direct current voltage of +25 to +20 VDC is output from the battery 1.

Connector CN2 is for transmitting and receiving various control signals between this uninterruptible power supply and other units. The control signals include a UPS enable signal, a power outage occurrence signal, an alarm signal, a discharge termination signal, and the like.

The UPS enable signal is a signal given from an external unit and instructs to enable the present uninterruptible power supply.

The power outage occurrence signal is also a signal given from an external device, and is used to notify the present uninterruptible power supply that a power outage has occurred. When the UPS enable signal is significant and this power outage occurrence signal becomes significant, the power of the battery 1 is output to the outside.

The alarm signal notifies an external device of an abnormality in the uninterruptible power supply, and is output when an overcurrent is supplied from the battery 1, for example.

The discharge end signal is a signal that notifies the external unit that the voltage output from the battery 1 of the present uninterruptible power supply has reached the discharge end voltage.

1 is a battery, which is a rechargeable and dischargeable secondary battery.

This battery 1 is composed of, for example, 8 x 6v monoblocks (one monoblock consists of 3 cells), and has +2
It outputs a DC voltage of 5V to +20V.

2 is a charging circuit as a charging power source, and battery 1
It is used to charge the battery. This charging circuit 2 operates an internal charging circuit by inputting power of +31 VDC from the outside, for example.

This charging circuit 2 is a ringing choke converter (RC
I-type switching regulator, +31 V
The operation starts when DC is input. Charging circuit 2 operates at +28.2VDC (2,35x
l 2 cells). In addition, the current detection point (OCP
) is set to 1~2A, so if the charge exceeds this
When t current flows, the output voltage decreases due to overcurrent drooping characteristics.

Resistors R1 and R2 are connected to the charge output from the charging circuit 2.
& voltage, and the voltage taken out from the connection point of these resistors R1 and R2 is applied to the battery voltage detection circuit 4a.
is being supplied to.

4a is a battery voltage detection circuit, and as shown in FIG. 1, one input is the voltage divided by the resistors R1 and R2, and the other input is the reference voltage Vref generated from a reference voltage generation circuit (not shown). As an input, it consists of an operational amplifier (comparator) that compares these. This pantry voltage detection circuit 4a detects the output voltage of the battery 1 through a resistor R1.
, R2 is compared with the reference voltage Vref, and when the divided voltage becomes smaller than the reference voltage Vref, a discharge end detection signal is output.

Then, the output of the above operational amplifier serves as the discharge end signal,
It is designed to be output to the outside via connector CN2.

SWI is a discharge circuit, and is composed of, for example, a semiconductor switch such as a MOS-FET. This discharge circuit SWI is U
It is turned on when both the PS valid signal and the power outage occurrence signal become significant. This discharge circuit SW
When I is turned on, discharging from the battery 1 is started.

6 is a non-fuse breaker (NFB), for example 5
When a current of 0A flows through the circuit, the current is automatically cut off.

7 is an abnormality detection circuit, which detects that the circuit is disconnected by the NFB 6 and outputs an alarm signal.

Next, the operation of the uninterruptible power supply having the above configuration will be explained. In the following example, it is assumed that the UPS enable signal has been made significant in advance.

Normally, the connector CNI is used for charging.]
VDC direct current power is supplied. Since the power failure occurrence signal is not significant and therefore the discharge circuit SWI is in the off state, this power is blocked by the discharge circuit SWI and is not directly supplied to the battery 1. Therefore, +31V
DC power is supplied only to the charging circuit 2 to operate the charging circuit 2 of the battery 1.

The output of this charging circuit 2 is applied to the battery 1 through the diode D2, thereby charging the pantry I.

On the other hand, when a power outage occurs, the power outage occurrence signal becomes significant and the discharge circuit SWI is turned on. At this time, connector CN
The +31 VDC power supply from I is no longer being supplied, and the battery 1 is discharged through the discharge circuit SW1 and the connector CNI to supply power to the load and the charging circuit 2. Note that current does not flow from the pantry 1 to the output terminal of the charging circuit 2 due to the diode D2.

The charging circuit 2 that receives the output from the battery 2 continues its operation. The output is equal to the battery voltage plus the forward voltage of the diode D2.

Detection of the discharge end voltage is performed by monitoring the output of this charging circuit 2. That is, the output voltage of the battery 1 is divided by resistors R1 and R2, and the battery voltage detection circuit 4
a, and the group 1! generated inside the circuit 4a. Voltage V
Compare with ref. When the battery voltage decreases to the discharge end voltage, the battery voltage detection circuit 4a outputs a discharge end detection signal indicating this fact. The external device that receives this discharge end detection signal opens the discharge circuit SWI by invalidating the UPS enable signal. As a result, discharging from the battery 1 is stopped, and the supply of power is stopped.

FIG. 5 is an application example of the present invention, and shows an example of a computer having an internal uninterruptible power supply as a countermeasure against computer power outages.

In the figure, 21 is a filter, 22 is a main line switch, 23 is a pre-regulator (PDL1), and 24 is an uninterruptible! #, a device (UPS), 25 a DC-DC converter, 26 a printed board unit, etc., and 27 a control section.

The filter 21 filters the commercial power supply of 100 VAC to remove noise and the like.

The line main switch 22 is a switch that turns on the power of the main body of the electronic meter 'xm.

The pre-regulator 23 inputs the commercial tifilo OVAC, converts it to +31 VDC direct current, and outputs it. This +31VDC DC power is supplied to the uninterruptible power supply 2.
4 and a DC-DC converter 25.

Further, this pre-regulator 23 has a power failure detection mechanism (not shown), and when a power failure is detected, it outputs a power failure occurrence signal.

This power failure occurrence signal is supplied to the uninterruptible AT power supply station 24.

The uninterruptible power supply 24 is the same as described above,
The explanation will be omitted here.

The DC-DC converter 26 converts +31 VDC output from the pre-regulator 23 or +25 VDC to +20 VDC output from the uninterruptible power supply 24, and converts +5
It generates DC voltages such as VDC and +12VDC used in normal logic circuits. The output of this DC-DC converter 25 is supplied to a printed board unit or the like 26.

The printed board unit 26 is a logic circuit or other load that consumes power.

The control unit 27 controls the entire electronic computer,
A UPS enable signal is output from the control section 27 and supplied to the uninterrupted TT power supply station 24. Also,
A discharge end signal is supplied to the control unit 27 from the uninterruptible power supply 24 .

Next, in the above configuration, the operation when a power outage occurs will be mainly explained.

First, when the main line switch 22 is turned on, commercial electric power fi100VAc is supplied to the computer. This is set to +31 VDC by the pre-regulator 23.
It is used as an input for the uninterruptible power supply 24.

On the other hand, this voltage +31VDC is supplied to the DC-DC converter 25, and the +31VDC voltage is supplied to the DC-DC converter 25.
Voltages used in normal logic circuits, such as 5V and ±12V, are generated and supplied to a load such as a printed board unit 26.

As mentioned above, the uninterruptible AT power source W24 has +31 VD.
The internal charging circuit is operated using C as input. The UPS enable signal and the power outage occurrence signal are connected to the discharge circuit SWI in the intangible TT power supply station 24, and when the UPS enable signal is coming from the control unit 27, the power outage occurrence signal comes from the pre-regulator 23, so that Discharge begins when a power outage occurs.

In this state, the battery voltage detection circuit 4a is connected to the charging circuit 2.
The output of the battery, that is, the voltage of the battery, is monitored, and when the battery voltage becomes equal to or lower than the discharge end voltage, a discharge end signal is output to the control section 27. Upon receiving this signal, the control unit 27 terminates the system normally, and then disables the UPS enable signal to activate the discharge circuit SW in the uninterruptible AT power supply station 24.
I is turned off to stop the discharge, and the power is cut off to stop all operations.

〔Effect of the invention〕

As described in detail above, according to the present invention, a high-multiplying, low-cost, uninterruptible power supply device that can prevent the occurrence of battery leakage current and reliably detect the end-of-discharge voltage even when the battery voltage is high. can be provided.

[Brief explanation of the drawing]

Figure 1 is a diagram to explain the principle of the present invention, Figure 2 is a diagram to explain the overcurrent drooping characteristics of a charging power source, Figure 3 is a diagram to explain the charging current characteristics, and Figure 4 is a diagram to explain the current characteristics of the charging power source. FIG. 5 is a block diagram showing the configuration of an applied example of the present invention; FIG. 6 is a block diagram showing a first example of a conventional uninterruptible power supply; FIG. The figure is a block diagram showing a second example of a conventional uninterruptible xits device, and FIG. 8 is a diagram showing an example of the impedance converter shown in FIG. 7. In the figure, 1... Battery 2... Charging power source (charging circuit), 3... Supply means, 4... Detection means, 4a... Comparator, R1, R2... Resistor, DI , D2...diode, SWI... switch means (discharge circuit). In the figures, the same reference numerals indicate the same or corresponding parts. Applicant Fujitsu Co., Ltd. 7/-.

Claims (5)

[Claims] (1) A chargeable and dischargeable battery (1), a charging power source (2) having constant current drooping characteristics for charging the battery (1), and a diode (D2) from the charging power source (2). In an uninterruptible power supply device configured to charge the battery (1) through a power supply, the supply means (3) supplies the output of the battery (1) to the charging power source (2) during a power outage, and the supply means (3) The battery (
Detection means (4) for detecting that the output of the charging power source (2) operated by the output of 1) has reached the discharge end voltage.
An uninterruptible power supply characterized by comprising: (2) The uninterruptible power supply according to claim 1, wherein the supply means (3) is constituted by a diode (D1) provided in series with the battery (1). (3) The detection means (4) divides the output voltage of the charging power source (2) and supplies it to a comparator (4a), and the comparator (4a) compares it with a reference voltage (Vref). 2. The uninterruptible power supply according to claim 1, wherein the end-of-discharge voltage is detected by. (4) The supply means (3) has a switch means (SW1) provided in series with the battery (1), and when the detection means (4) detects the discharge stop voltage, the switch means The uninterruptible power supply according to claim 1, characterized in that (SW1) is opened. (5) A chargeable and dischargeable battery (1) and a charging power source (2) having a constant current drooping characteristic for charging the battery (1), and a diode (D2) from the charging power source (2). In the uninterruptible power supply device, the battery (1) is charged by the charging power supply (2) which normally operates with external power, and during a power outage. discharges the battery (1) and outputs it to the outside, and also supplies power to the charging power source (2), and sets the output of the charging power source (2) driven by this battery (1) to a reference voltage (Vref). ) is the end of discharge detection method for an uninterruptible power supply that detects when the end of discharge voltage has been reached.