JPH04101249U - power compensation device - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a power supply compensation device that can extend the service life of a storage battery by installing a plurality of storage batteries and sequentially replacing the storage batteries that are discharged every time there is a power outage. [Structure] In the power supply compensation device 1, each time the power supply voltage detection circuit 9 detects a power outage, the discharge control circuit 15
Alternatively, one of the second batteries 5b is designated alternately, and the discharge circuit 13
discharges from the designated battery 5a or 5b to the load L to compensate for the power supply during a power outage. When the power outage is prolonged and the battery voltage detection circuit 11 detects a voltage drop in the first battery 5a or the second battery 5b, the discharge control circuit 15 switches the designation from one battery 5a or 5b to the other battery 5b or 5a. Then, the first and second
The batteries 5a and 5b are continuously discharged to compensate for the power supply to the load L for a long time.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is a direct current generator that generates direct current from alternating current when an external alternating current power supply fails. The present invention relates to a power supply compensation device that supplies direct current from a storage battery to a load instead of a power source.

0002

[Conventional technology]

Conventionally, when an external AC power supply fails, a rechargeable battery supplies power to the load in place of the DC power supply. A power supply compensation device is known. For example, as shown in Figure 7, the rectifier circuit Rec and A well-known DC power supply 52 consisting of a smoothing capacitor C and a backup of the DC power supply 52. A rechargeable battery (hereinafter referred to as a battery) 54 used and a load L are disconnected from the battery 54 and the load L. A series transistor circuit 56 consisting of a diode D and a current limiting resistor R A trickle charging circuit 58 that charges the battery 54 with a minute current, and A power failure detection circuit 60 detects a voltage drop in the DC power supply 52 due to electric power, and a battery voltage regulation circuit 60. A battery voltage detection circuit 62 that detects a drop below the rated voltage, a power failure detection circuit 60, and Drives the transistor circuit 56 based on the detection signal from the battery voltage detection circuit 62 A power supply compensation device comprising a control circuit 64 that controls discharge from the battery 54 by 50 are known. In this type of device, the battery 54 is made of nickel, for example. - Cadmium batteries (hereinafter referred to as nickel-cadmium batteries) are often used.

0003 In this device 50, when AC power is supplied, the signal from the power failure detection circuit 60 is When the level is Low and the signal level from the battery voltage detection circuit 62 is High. Therefore, since the output of the AND element AND of the control circuit 64 is Low, the Transistors Tr1 and Tr2 of the transistor circuit 56 are turned off, and the battery 54 and DC power supply are disconnected. 52. On the other hand, when the AC power supply AC is out of power, the power outage detection circuit 60 As the signal level from the battery voltage detection circuit 62 becomes High, the signal level from the battery voltage detection circuit 62 becomes High. Since it remains High, the output level of the AND element AND changes to High. So As a result, transistors Tr1 and Tr2 are turned on to connect the battery 54 and the load L. child As a result, power is supplied from the battery 54 to the load L side, and the power supply is compensated.

0004 If the power outage continues and the voltage of the battery 54 falls below the predetermined voltage, the battery voltage detection circuit The signal from line 62 turns low, so the output level of AND element AND becomes low. It becomes ow. As a result, transistors Tr1 and Tr2 are turned off and the battery 54 is discharged. Stop. This prevents over-discharging of the battery 54.

[0005] In this way, the power supply compensation device 50 compensates for the power supply while preventing overcharging and overdischarging. It is widely used to keep various devices operating during power outages. and For example, in information processing equipment, lightning can cause an instantaneous interruption of the power supply (hereinafter referred to as an instantaneous power outage). A power supply compensator is used to prevent the data stored in the memory element from being erased. During periods when lightning occurs frequently, the power supply compensator 50 often operates and reduces the power supply. Power is supplied from the battery 54 to the information processing device.

[0006]

[Problem that the idea aims to solve]

By the way, the lifespan of a NiCd battery is determined by the number of charge-discharge cycles, and generally It is about 300 to 500 times. Also, overcharging and overdischarging can cause damage to internal cells. This can significantly shorten battery life.

[0007] However, with the above device 50, shortening of battery life due to overcharging and overdischarging cannot be prevented. However, the battery 54 discharges and charges as many times as there is a power outage or momentary interruption, so it is not necessary to replace the battery. As the battery reaches its early stage, problems arise such as the need to replace the battery more frequently and time consuming. .

[0008] Therefore, the present invention aims to install multiple storage batteries and replace the storage batteries that discharge each time there is a power outage. The purpose of the present invention is to provide a power supply compensation device that can extend the service life of storage batteries. .

[0009]

[Means to solve the problem]

The gist of this idea is: A DC power supply that generates DC from AC and supplies power to a load; a storage battery that is charged by being supplied with power from the DC power source; Detects that the output voltage of the DC power supply mentioned above has fallen below the predetermined first reference voltage. a power supply voltage detection circuit, Detects that the output voltage of the storage battery has fallen below a predetermined second reference voltage. A storage battery voltage detection circuit, The output voltage of the DC power supply is lower than or equal to the first reference voltage by the power supply voltage detection circuit. When it is detected that the storage battery is falling, the storage battery discharges to the load, and the storage battery discharges to the load. The battery voltage detection circuit causes the output voltage of the storage battery to drop below the second reference voltage. a discharge control circuit that stops the discharge when it is detected that In a power supply compensator equipped with In addition to providing a plurality of the above storage batteries, The power supply voltage detection circuit detects that the output voltage of the DC power supply falls below the first reference voltage. Each time it detects that the rain is falling, one of the plurality of storage batteries is selected in a predetermined circulation order. a connection switching circuit that selects and connects to the discharge control circuit; The power supply compensation device is characterized by:

0010

[Effect]

According to the power supply compensation device configured as described above, the power supply voltage detection circuit When it detects that the output voltage has fallen below the first reference voltage, the connection is switched. The circuit selects one of the multiple storage batteries in a predetermined circulation order and connects it to the discharge control circuit. . Then, the discharge circuit discharges the connected storage battery to the load. due to discharge The output voltage of the storage battery decreases, and the storage battery voltage detection circuit detects that the output voltage is the second standard. When detecting that the voltage has dropped below the voltage, the discharge control means stops the discharge of the storage battery. Stop.

[0011] In this way, each time the power supply voltage detection circuit performs the above detection operation, One of the multiple storage batteries is selected and discharged. Therefore, the discharge of individual storage batteries - The number of times of charging is the number of times of the above-mentioned detection operation divided by the number of storage batteries.

0012

【Example】

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an electrical circuit diagram of a power supply compensation device to which the present invention is applied.

[0013] As shown in the figure, the power supply compensator 1 is supplied with power from an alternating current power source AC to generate direct current. DC power supply 3, and first and second rechargeable batteries (hereinafter referred to as the first battery and the second battery). c) 5a and 5b, a charging circuit 7 that charges the first and second batteries 5a and 5b, and a DC A power supply voltage detection circuit 9 detecting a decrease in the output voltage VDC of the power supply 3 and a power supply voltage detection circuit 9 for detecting a decrease in the output voltage VDC of the power supply 3; A battery voltage detector detects a decrease in the output voltage VBT1 and the output voltage VBT2 of the second battery 5b. An output circuit 11 and a discharge circuit for discharging from the first or second battery 5a or 5b to the load L. The main parts are the circuit 13 and the discharge control circuit 15 that controls the discharge by the discharge circuit 13. It is composed of

[0014] The DC power supply 3 includes a step-down transformer TR, a diode bridge circuit DB, and a smoothing circuit. This is a well-known circuit consisting of a capacitor C1. The first and second batteries 5a and 5b are batteries with the same capacity and the same electromotive force, for example, the same Two NiCad batteries are used.

[0015] The charging circuit 7 includes diodes D1 and D2 provided in the forward direction with respect to the DC power supply 3. and reverse diodes D3 and D4 and current limiting resistors Ra and Rb. battery When the voltages VBT1 and VBT2 of 5a and 5b are lower than the output voltage VDC of the DC power supply 3, A predetermined voltage is supplied from the current power source 3 through diodes D1, D2 and current limiting resistors R1, R2. The batteries 5a and 5b are charged with a minute current. On the other hand, what happens to batteries 5a and 5b during a power outage? From either side, the device is connected through current limiting resistors R1, R2 and diodes D3, D4. A current path is formed for supplying the operating power supply VCC to each section 9, 11, 15 of the device.

[0016] Note that the current during charging is minute, and when the batteries 5a, 5 are fully charged, This is enough to compensate for the natural self-discharge of battery 5a and 5b, so batteries 5a and 5b are not charged for a long time. will not become overcharged.

[0017] The power supply voltage detection circuit 9 detects when the output voltage VDC of the DC power supply 3 falls below the first reference voltage. This circuit detects that the The current limiting resistor R3 and the anode voltage of the Zener diode DZ1 are the first reference voltage. When the voltage drops below, a power failure detection signal (Low active) SOFF is sent to the discharge control circuit 15. and a voltage monitoring circuit MON.

[0018] Note that the first reference voltage is higher than the power supply voltage VDC, which decreases when the power consumption of the load L increases. The output voltage VDC is set at a sufficiently low level, and the output voltage VDC due to a power outage of the AC power supply is It is set in a voltage range where it is clear that there is a drop in the Zener diode DZ1. uses an element whose breakdown voltage is the first reference voltage. In addition, the voltage monitoring circuit MON For example, the M51945 manufactured by Mitsubishi Electric Corporation is a well-known integrated circuit. The details are omitted.

[0019] The battery voltage detection circuit 11 detects the output voltage VB1 of the first battery 5a and the output voltage of the second battery 5b. This circuit detects that the power voltage VB2 has fallen below the second reference voltage, and has the same structure. The voltage detection circuit 11 is composed of two sets of voltage detection circuits 11a and 11b. Voltage detection circuit 11 a is a Zener diode DZ2, a current limiting resistor R4, and a first voltage monitoring circuit M. The voltage detection circuit 11b includes a Zener diode DZ3 and a current control circuit. It consists of a limiting resistor R5 and a second voltage monitoring circuit MNb. 1st/2nd voltage monitoring circuit M For Na and MNb, the anode voltage of Zener diodes DZ2 and DZ3 is the second reference voltage. When the voltage drops below, the first detection signal SBT1 and the second detection signal SBT2 (both are H igh active) is output to the discharge control circuit 15.

[0020] Note that the second reference voltage is lower than the rated output voltage of the batteries 5a and 5b, and Zener diodes DZ2, D For Z3, an element whose breakdown voltage is the second reference voltage is used. In addition, the first and second voltages The monitoring circuits MNa and MNb are of the same type as the voltage monitoring circuit MON of the power supply voltage detection circuit 9. It is.

[0021] The discharge circuit 13 includes a first transistor circuit that discharges from the first battery 5a to the load L. line 13a, and a second transistor circuit 13 for discharging from the second battery 5b to the load L. b, and the first or second discharge command signal input from the discharge control circuit 15 ( High Active (details will be explained later) Discharge timing is controlled by SCH1 or SCH2 be done. That is, the first or second discharge command signal SCH1 or SCH2 is input. and the two transistors Tr1 and Tr2 of the first transistor circuit 13a or the second transistor The two transistors Tr3 and Tr4 of the transistor circuit 13b are driven to cause discharge. Ru. Further, an electrolytic capacitor C2 is provided between the discharge circuit 13 and the load L, The output voltage of the discharge circuit 13, that is, the output voltage VBT of the first or second battery 5a or 5b 1 or VBT2, or the output voltage VDC of the DC power supply 3.

[0022] Note that the first and second transistor circuits 13a and 13b are well-known switching transistors. Since this is a circuit, details will be omitted. The discharge control circuit 15 is one of the first or second transistor circuit 13a or 13b. This is a battery selection command that selects the battery 5a or 5b to be discharged. a transistor circuit 15a, and a first transistor circuit 13a or a second transistor circuit depending on its selection. A discharge command circuit 15b that commands discharge to the register circuit 13b and a timing of a power outage. A timing detection circuit 15c that detects a failure of the second battery 5b and a failure that detects a failure of the second battery 5b. The detection circuit 15d is the main part.

[0023] The battery selection circuit 15a includes a D-type flip-flop FF and a flip-flop F. It consists of a logic circuit LG that determines the timing of data latch of F. The flip-flop FF has a logic circuit LG input to its clock terminal CL. It is input to the data terminal D at the timing when the latch signal SLT rises. Level signal (terminal Q) and its inverted signal (inverted Q terminal) according to the signal level , are outputted to the discharge command circuit 15b as first and second designation signals SQ and SNQ.

[0024] In addition, the flip-flop FF is supplied with a one-shot pulse signal (high actuation signal). A pulse circuit IN is attached to output the battery 5. When a and 5b are installed, the pulse signal (High active) is sent to the flip-flop. The signal is output to the set terminal S of the FF to set the flip-flop FF to its initial state. That is, the first designation signal SQ goes High and the second designation signal SNQ goes Low. Set.

[0025] The logic circuit LG includes an AND element AND1 and two OR elements OR1 and OR2. Power outage detection signal SOFF from voltage monitoring circuit MON, 1st and 2nd voltage monitoring circuit The first and second detection signals SBT1 and SBT2 from the paths MNa and MNb and the failure detection circuit 15 Based on the failure detection signal SER from d, a latch signal SLT is output. this latch The signal SLT becomes Low when the power outage detection signal SOFF is input, and the signal SLT goes low when the power outage detection signal SOFF is input. (hereinafter referred to as power restoration), or if the discharge of either battery 5a or 5b is prolonged. When the detection signal SBT1 or SBT2 is input, it changes to High.

[0026] The discharge command circuit 15b consists of two negative sum elements NO1 and NO2, and has a battery selection circuit. The first and second designation signals SQ and SNQ from the path 15a, the power outage detection signal SOFF, and the first ・Based on the second detection signals SBT1 and SBT2, the first or second discharge command signal SCH1 or outputs SCH2 to the first transistor circuit 13a or the second transistor circuit 13b. Strengthen.

[0027] The timing detection circuit 15c consists of a delay circuit DL and an OR element OR3. , a short one-shot pulse ( Failure detection circuit 1 uses Low active, pulse width Δt) as power outage start detection signal SED Output to 5d.

[0028] Note that since the timing detection circuit 15c is a well-known pulse/edge detection circuit, , the explanation is omitted. The failure detection circuit 15d consists of a logical sum element OR4, and the From the first and second discharge command signals SCH1 and SCH2 and the timing detection circuit 15c. Based on the power outage start detection signal SED, the second battery 5b fails during the power outage and If the output voltage VBT2 does not rise above the second reference voltage even after charging, then One-shot pulse failure detection signal (Low active) when power outage occurs Output SER.

[0029] Note that each element of each of the circuits 15a to 15c has extremely low power consumption. Semiconductor elements or integrated circuits are used to power the first and second batteries 5a and 5b during a power outage. There is no impact on the compensation period.

[0030] Next, the operation of the power supply compensation device 1 will be explained. First, as shown in Figure 3, at the stage when the first and second batteries 5a and 5b are installed, a power outage occurs. The detection signal SOFF is Low and the flip-flop FF is set to the initial state. Ru. After that, when the AC power supply AC is turned on (hereinafter simply referred to as power-on), (t0 ), when the power outage detection signal SOFF becomes High, the latch signal SLT also changes to High. . As a result, the first designation signal SQ goes low and the second designation signal SNQ goes high, respectively. In turn, the second discharge command signal SCH2 becomes Low (the first discharge command signal SCH1 becomes Low). ). After the power is turned on, the first and second batteries 5a and 5b are charged enough to compensate for self-discharge. It is charged with a minute current and maintained in a fully charged state.

[0031] Assume that a power outage occurs here (t1). Then, the power outage detection signal SOFF goes low. Therefore, the first discharge command signal SCH1 changes to High and discharge of the first battery 5a starts. (The latch signal SLT turns Low). Short time (power supply compensation period by battery 5a) When the power outage is restored (within time Ta) (t2), the power outage detection signal SOFF returns to High. . Therefore, the latch signal SLT changes to High, and at that timing the first designated signal S Since Q changes to High, the discharge command signal SCH1 returns to Low. As a result, the first Discharging of the battery 5a is stopped.

[0032] When a power outage occurs again (t3), the power outage detection signal SOFF becomes Low, and as a result, the Since the second discharge command signal SCH2 changes to High, discharging of the second battery 5b is started. . When the power outage is restored within a short time (within the power supply compensation period Tb by the battery 5b) (t4) , the power outage detection signal SOFF returns to High. Therefore, the latch signal SLT changes to High. At the same time, the second designation signal SNQ changes to High, so the second discharge command signal No. SCH2 returns to Low. As a result, discharging of the second battery 5b is stopped.

[0033] When the third power outage occurs (t5), the first battery 5 The discharge of a is started. After that, in the same way, every time a power outage occurs, the first battery 5a and the second battery 5b alternately discharge to compensate for power supply to the load L.

[0034] Next, a case where the power outage continues for a long time will be explained. As shown in Figure 4, when a power outage occurs (t11), the power outage detection signal SOFF goes low. As a result, the first battery 5a starts discharging. The power outage continues and the first battery 5a is drained. When the power voltage VBT1 falls below the second reference voltage (t12), the first detection signal SBT1 Since it becomes High, the latch signal SLT changes to High. Therefore, the first and second fingers Since the constant signals SQ and SNQ are inverted, the first discharge command signal SCH1 goes low and the second discharge Command signal SCH2 becomes High. That is, when the discharge of the first battery 5a is stopped, At the same time, discharging of the second battery 5b is started. Power is restored within the compensation period Tb of the second battery 5b Then (t13), the power outage detection signal SOFF returns to High, so the second discharge command signal SCH2 goes low. That is, discharging of the second battery 5b is stopped. When a power outage occurs again (t14), the power outage detection signal SOFF becomes Low, and as a result, The second discharge command signal SCH2 becomes High, and the second battery 5b is discharged. power outage If the voltage VBT2 of the second battery 5b decreases below the second reference voltage (t1 5) Since the second detection signal SBT2 becomes High, the latch signal SLT changes to High. Ru. Therefore, since the first and second designation signals SQ and SNQ are inverted, the first discharge The command signal SCH1 becomes High and the second discharge command signal SCH2 becomes Low. That is, the first At the same time as the discharge of the battery 5a is started, the discharge of the second battery 5b is stopped.

[0035] If the power outage is further prolonged and the output voltage of the first battery 5a also drops below the second reference voltage, (t16), the first detection signal SBT1 becomes High, so the first discharge command signal SCH1 becomes Low, and the discharge of the first battery 5a is also stopped. The power outage continues for a long time like this. In such a case, one battery 5b or 5a may be connected to the other battery 5a or 5b. The discharge continues, and the longest discharge duration is the period between the first battery 5a and the second battery 5b. This is the total power supply compensation period (Ta+Tb).

[0036] Furthermore, a case will be explained in which one of the batteries 5a or 5b breaks down after the power is turned on. do. As shown in FIG. 5, when the second battery 5b fails during a power outage, it is charged after the power is restored. Even if it is detected, the output voltage VBT2 does not rise above the second voltage, and the second detection signal SBT2 is Fixed to High. Therefore, the second discharge command signal SCH2 is also fixed to Low. A discharge command is not given to the two-transistor circuit 13b.

[0037] Assume that a power outage occurs (t21) while the second battery 5b remains in failure. Then, a power outage check Since the output signal SOFF becomes Low, the power failure start detection signal SED is output. but, Since the first designated signal SQ is High, even if the power outage detection signal SOFF goes Low, the first designated signal SQ is High. The power command signal SCH1 remains low. Therefore, the failure detection signal SER is It changes from low to high in synchronization with the detection signal SOFF, and as a result, the latch signal SLT also changes in the same way. It changes from low to high. At the timing when this latch signal SLT rises, The first designation signal SQ turns low. As a result, the first discharge command signal SCH1 becomes High. , and discharge of the first battery 5a is started.

[0038] If the power outage becomes longer and the output voltage of the first battery 5a also drops below the second reference voltage ( t22), the first detection signal SBT1 becomes High, so the first discharge command signal SCH1 becomes High. It becomes Low, and discharging of the first battery 5a is also stopped. Therefore, the longest power supply compensation period is the power supply compensation period Ta by the first battery 5a.

[0039] When a power outage occurs after that, the first designated signal SQ is Low, so the power outage occurs. As the electricity detection signal SOFF becomes Low, the first discharge command signal SCH1 becomes High, When the power outage detection signal SOFF returns to High or the first detection signal SBT1 becomes High Both become Low, and the first battery 5a is discharged during that period.

[0040] In addition, from the time the first power outage (t21) is detected until the discharge starts, the power outage There is a delay time equal to the pulse width Δt of the start detection signal SED, but when the pulse width Δt is extremely It is short and the output voltage to the load L is stabilized by the electrolytic capacitor C2. Thus, the output voltage from the power supply compensator 1 to the load L is held constant.

[0041] On the other hand, as shown in FIG. 6, when the first battery 5a fails, it The output voltage VBT1 does not rise above the second voltage, and the second detection signal SBT2 is fixed at High. determined. Therefore, the first discharge command signal SCH1 is also fixed to Low and the first transistor A discharge command is not issued to the star circuit 13a.

[0042] Assume that a power outage occurs (t31) while the second battery 5b remains in failure. Then, a power outage check Since the output signal SOFF becomes Low, the power failure start detection signal SED is output. At this time , the second designation signal SNQ and the second detection signal SBT2 are Low, so the power outage detection signal SOF As soon as F becomes Low, the second discharge command signal SCH2 becomes High, and the second battery 5b becomes low. Discharge begins.

[0043] As the power outage continues to prolong, the output voltage VBT2 of the second battery 5b drops below the second reference voltage. (t32), the second detection signal SBT2 becomes High, so the second discharge command signal SCH2 goes low and the discharge of the first battery 5a is also stopped. Therefore, the longest power The compensation period is a power supply compensation period Tb using the second battery 5b.

[0044] If a power outage occurs after that, the second designation signal SNQ will be Low. ,, When the power outage detection signal SOFF becomes Low, the second battery 5b starts discharging and then stops again. When the voltage detection signal SOFF returns to High or the second detection signal SBT2 becomes High, the second detection signal SOFF returns to High. Discharging of the second battery 5b is stopped.

[0045] As explained above, in this embodiment, each time a power outage occurs, the first battery 5a and the second battery Since the batteries 5b and 5b discharge alternately, the number of discharges and charges of the first and second batteries 5a and 5b is The number of power outages is reduced to half, and battery life is doubled. Therefore, it is time to replace the battery. Since the time period is extended, the trouble of replacing batteries can be reduced.

[0046] Furthermore, in the event of a prolonged power outage, the first and second Since two batteries 5a and 5b are discharged, long-term power supply compensation is possible. In addition, even if one battery 5a or 5b fails, the other normal battery 5b or 5 Power supply compensation can be performed by discharging a, increasing the reliability of power supply compensation. There is also this effect.

[0047] In addition, if the power outage is prolonged and the battery voltages VBT1 and VBT2 drop below the second reference voltage, the battery will be discharged. Stop power to prevent over-discharge, and after power is restored, charge with a small current to prevent over-charge. Therefore, the first and second batteries 5a and 5b can be maintained in a stable state. This also helps extend battery life.

[0048] Alternatively, the total power supply compensation period of the first battery 5a and the second battery 5b (Ta+Tb ) is the same as the power supply compensation time of the conventional device, the capacity of both batteries 5a and 5b The capacity can be half of that of one conventionally used battery. In other words, a small capacity battery Since you only need to use two batteries, there is no need to use expensive large-capacity batteries, reducing production costs. is also successful.

[0049] Note that in this embodiment, the first or second transistor circuit 13a of the discharge circuit 13 or 13b is configured to alternately discharge from the first or second battery 5a or 5b. However, in addition to this, a configuration may be adopted in which discharge is performed using one transistor circuit. Ta For example, if a discharge circuit is configured with one transistor circuit, then this transistor circuit is Driven by the OR signal of two discharge command signals SCH1 and SCH2, and discharge Between the circuit and the first battery 5a and second battery 5b, first and second designation signals SQ and Provide a relay circuit or analog multiplexer driven based on SNQ, By connecting the selected first or second battery 5a or 5b and the transistor circuit. , the discharge to the load L may be performed. In this case, the circuit of the discharge circuit Configuration becomes easier.

[0050]

[Effect of the idea]

As detailed above, according to the present invention, each time a power outage occurs, multiple Since one of the storage batteries is selected and discharged, the number of discharges and charges for each storage battery is Since the number of power outages is reduced to at least half of the number of power outages, battery life can be extended. death Therefore, the time required for battery replacement becomes longer, and the time and effort required for battery replacement can be reduced.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram of a power supply compensation device according to an embodiment.

FIG. 2 is an electrical circuit diagram of a discharge control circuit.

FIG. 3 is a timing chart showing the operation of the power supply compensation device when a short power outage continues.

FIG. 4 is a timing chart showing the operation of the power supply compensation device when a power outage is prolonged.

FIG. 5 is a timing chart showing the operation of the power supply compensation device when the second battery fails.

FIG. 6 is a timing chart showing the operation of the power supply compensation device when the first battery fails.

FIG. 7 is an electrical circuit diagram showing a conventional power supply compensation device.

[Explanation of symbols]

1... Power supply compensation device 3... DC power supply 5a... First battery 5
b...Second battery 7...Charging circuit 9...Power supply voltage detection circuit 11...
Battery voltage detection circuit 13...Discharge circuit 15...Discharge control circuit 15a...Battery selection circuit 15b...Discharge command circuit 15c
…Failure detection circuit AC…AC power supply L…Load

Claims (1)

[Scope of utility model registration request] 1. A DC power supply that generates DC from AC to supply power to a load, a storage battery that is charged by being supplied with power from the DC power supply, and an output voltage of the DC power supply that drops below a predetermined first reference voltage. a power supply voltage detection circuit that detects that
A storage battery voltage detection circuit detects that the output voltage of the storage battery has fallen below a predetermined second reference voltage, and the power supply voltage detection circuit detects that the output voltage of the DC power supply has fallen below the first reference voltage. When it is detected that the output voltage of the storage battery is lower than the second reference voltage, the storage battery is discharged to the load, and when the storage battery voltage detection circuit detects that the output voltage of the storage battery has fallen below the second reference voltage, the discharge is performed. and a discharge control circuit that stops, a plurality of the storage batteries are provided, and the power supply voltage detection circuit detects that the output voltage of the DC power supply has fallen below the first reference voltage. A power supply compensating device characterized in that a connection switching circuit is provided for selecting one of the plurality of storage batteries in a predetermined circulation order and connecting it to the discharge control circuit at each time.