JP3402357B2 - Battery life diagnosis method for uninterruptible power supply - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery life diagnosing method, and more particularly to a battery life diagnosing method for an uninterruptible power supply capable of accurately diagnosing a battery life without stopping power supply to a load.

[0002]

2. Description of the Related Art FIG. 6 shows a block circuit diagram of an uninterruptible power supply device which has been widely used conventionally. This uninterruptible power supply system includes a converter circuit (2) for converting AC power from a single-phase commercial AC power supply (1) into DC power, and a converter circuit (2).
An inverter circuit (3) that converts the DC output of the AC output to an AC output and supplies it to the load (5); and a battery (4) connected between the converter circuit (2) and the inverter circuit (3). There is.
The input current detector (6) provided between the commercial AC power supply (1) and the converter circuit (2) detects the AC input current I _AC of the converter circuit (2) as a voltage V _IA corresponding to the current. To do. A discharge current detector (7) connected to the positive terminal of the battery (4) detects the discharge current I _BT of the battery (4) as a voltage V _IB corresponding to the current. The thermistor (8) placed adjacent to the battery (4) detects the ambient temperature of the battery (4) as a voltage corresponding to the ambient temperature, and the digital thermometer (9) detects the detected voltage of the thermistor (8). Is displayed as the temperature. In the uninterruptible power supply device shown in FIG. 6, the converter circuit (2) and the inverter circuit are normally connected from the commercial AC power supply (1).
The AC output is supplied to the load (5) via (3), and the battery (4) is charged by the DC output of the converter circuit (2).
During a power failure of the commercial AC power supply (1), DC power is supplied from the battery (4) to the inverter circuit (3), and AC output is supplied from the inverter circuit (3) to the load (5). The bypass circuit (10) connected between the commercial AC power source (1) and the load (5) includes an AC switch (11) composed of an antiparallel circuit of a thyristor or a triac. When the converter circuit (2) or the inverter circuit (3) fails or the load (5) is overloaded, the AC switch (11) of the bypass circuit (10) is switched on at high speed to turn on the commercial AC. The AC power of the power supply (1) can be directly supplied to the load (5) without interruption.
Furthermore, a circuit breaker provided on the output side of the inverter circuit (3)
Converter circuit by switching off (12)
(2) or when the inverter circuit (3) fails or the load (5) is overloaded, load the output of the inverter circuit (3) with the load (5)
Can be separated from.

As shown in FIG. 7, a converter circuit (2)
Is the input capacitor (13) connected to both ends of the commercial AC power supply (1), the switching circuit (15) connected to the input capacitor (13) via the reactor (14), and the switching circuit (15). Smoothing capacitor (20) connected between output terminals
And a converter control circuit (21). The switching circuit (15) includes first to fourth parasitic diodes (16a) to
It is configured by bridge-connecting first to fourth IGBTs (insulated gate bipolar transistors) (16) to (19) having (19a). The converter control circuit (21) has a DC voltage V _DC
Alternatively, depending on the detection voltage V _{IB of the} discharge current detector (7) and the detection voltage V _IA of the input current detector (6), the first and fourth IGBTs (16), (19) in the switching circuit (15). It also outputs first and second ON / OFF control signals V _G1 and V _G2 with variable duty ratios, which are applied to the gate terminals of the second and third IGBTs (17) and (18), respectively.

The converter control circuit (21) includes a first error amplifier (24), a set voltage generating means (22) connected to a non-inverting input terminal of the first error amplifier (24), and a first error amplifier (24). Error amplifier
With the changeover switch (23) connected to the inverting input terminal of (24),
Proportional integrator connected to the output side of the first error amplifier (24)
(25) and a sine wave generation circuit (26) for generating a reference sine wave signal V _RS synchronized with the _AC input voltage V _AC of the commercial AC power supply (1)
And a multiplication circuit (27) for outputting a product signal V _M1 of the proportional integration signal V _S of the proportional integrator (25) and the reference sine wave signal V _RS of the sine wave generation circuit (26), and a multiplication circuit (27) A second error amplifier (28) having an inverting input terminal connected to and a non-inverting input terminal connected to the input current detector (6), and a second error amplifier (2
PWM comparator (30) having a non-inverting input terminal for receiving the output of 8), a triangular wave oscillator (29) connected to the inverting input terminal of the PWM comparator (30), and the output of the PWM comparator (30) First control signal generation circuit (31)
And a second control signal generation circuit (33) for receiving the output of the PWM comparator (30) via the inverter (32).

The setting voltage generating means (22) is a converter circuit.
DC voltage V output from (2)_DCThe setting that controls the set value of
Constant voltage V_RDIs output. The selector switch (23) is a contact (A).
And contact (B) at the end of charging the battery (4)
Between contact (A) and (B) during constant current charging of (4)
Switch. The first error amplifier (24) has a changeover switch (2
When 3) is closed on the contact (A) side, DC voltage V_DCAnd setting power
Set voltage V of pressure generation means (22)_RDThe level difference between
When the selector switch (23) is closed on the contact (B) side,
Flow detector (7) detection voltage V_IBAnd the setting voltage generation means (22)
Set voltage V_RDAnd the level difference with. Proportional Integrator (25)
Is the output signal V of the first error amplifier (24) _E1Ratio
Example integration signal V_SIs output. The second error amplifier (28) is
Detection signal V of input current detector (6)_IAAnd the multiplication circuit (27)
Signal V_M1And the level difference with. Triangular Wave Oscillator (29)
Is the switching frequency of the first to fourth IGBTs (16) to (19).
A reference triangular wave signal V of 20 kHz for controlling the wave number_T1To
Output. The PWM comparator (30) has a second error amplification
Output signal V of the container (28)_E2And triangular wave oscillator (29) reference triangular wave
Signal V_T1And the PWM modulation signal V_PWMTo form
It The first control signal generation circuit (31) includes first to fourth IGs.
Dead, which is the period when all BT (16) to (19) are in the off state
Time is the PWM modulation signal V of the PWM comparator (30)
_PWMIn addition to the first ON / OFF control signal V_G1To form
It The inverter (32) is the PWM converter of the PWM comparator (30).
Key signal V_PWMInversion signal -V_PWMIs output. Second control
The signal generation circuit (33) outputs the output signal -V of the inverter (32)._PWMTo
A second on / off control signal with the dead time added
V_G2To form.

By the first and second on / off control signals V _G1 and V _G2 output from the first and second control signal generating circuits (31) and (33) of the converter control circuit (21), respectively, A pair of first and fourth provided in the switching circuit (15)
IGBTs (16), (19) and a pair of second and third IGs
By alternately turning on / off the BTs (17) and (18), the AC input voltage V _AC from the commercial AC power supply (1) can be converted into the DC voltage V _DC . When the battery (4) is fully charged, the changeover switch (23) in the converter control circuit (21) is closed on the contact (A) side. Therefore, the duty ratios of the first and second on / off control signals V _G1 and V _G2 are controlled according to the DC voltage V _DC and the detection voltage V _IA of the input current detector (6), and the first and the second The on / off periods of the four IGBTs (16) and (19) and the second and third IGBTs (17) and (18) are controlled. That is, in the converter control circuit (21), the DC voltage V _DC
Is higher than the level of the set voltage V _RD of the set voltage generating means (22), the first and second ON / OFF control signals V _G1 and V _G2 having narrow pulse widths are formed to form the first and fourth IGBTs. (1
6), (19) and the level of the DC voltage V _DC output from the converter circuit (2) is reduced by narrowing the pulse width of the gate output given to the second and third IGBTs (17), (18). can do. On the contrary, when the DC voltage V _DC is lower than the level of the set voltage V _RD of the set voltage generating means (22), the first and second ON / OFF control signals V _G1 and V _{G having} a wide pulse width are provided.
_G2 is formed to widen the pulse width of the gate output given to the first and fourth IGBTs (16) and (19) and the second and third IGBTs (17) and (18), and the converter circuit (2 ), The level of the DC voltage V _DC output from can be increased.

On the other hand, as the reference voltage signal indicative of the level of the AC input current I _AC supplied from the commercial AC power source (1), the proportional integral signal V _S of the multiplier circuit (27) is a proportional integrator (25)
And a product signal V _M1 of the reference sine wave signal V _RS of the sine wave generating circuit (26). The second error amplifier (28) includes a multiplication circuit (2
The output corresponding to the level difference between the product signal V _{M1 of} 7) and the detection signal V _IA of the input current detector (6) is given to the first and second control signal generation circuits (31) (33), It controls the pulse widths of the first and second on / off control signals V _G1 and V _G2 . As a result, the DC voltage V _DC at the completion of charging the battery (4) is kept constant, and the AC input current I _AC is changed to the AC input voltage V _AC.
It is controlled in proportion to _AC , and the input power factor becomes approximately 1.0. When charging the battery (4), the converter control circuit (21)
The change-over switch (23) in the inside closes to the contact (B) side, and the first and second switches are set according to the detection voltage V _{IB of} the discharge current detector (7) and the detection voltage V _IA of the input current detector (6). ON / OFF control signal V _G1 ,
The duty ratio of V _G2 is controlled, and the first and fourth IGBs are controlled.
T (16), (19) and second and third IGBT (17), (18)
The on / off period of is controlled. As a result, the battery (4) is charged with a constant current and the AC input current I
_AC is controlled in proportion to the _AC input voltage V _AC , and the input power factor becomes approximately 1.0.

Further, as shown in FIG. 8, an inverter circuit
(3) is a switching circuit (35) connected to the DC input terminal via the input capacitor (34) and a switching circuit (3
A filter reactor (40) and a filter capacitor (41) connected between the AC output terminal of 5) and the load (5), a capacitor current detector (42), and an inverter control circuit (43). There is. The switching circuit (35) includes fifth to eighth parasitic diodes (36a) to (39a) and fifth to eighth IGBTs.
It is configured by connecting T (36) to T (39) in a bridge connection. The capacitor current detector (42) detects the current I _C flowing through the filter capacitor (41) as a voltage V _C corresponding to the current.
The inverter control circuit (43) is provided in the switching circuit (35) according to the AC output voltage V _O supplied to the load (5) from both ends of the filter capacitor (41) and the detection voltage V _C of the capacitor current detector (42). Third and fourth on / off control signals V applied to the respective gate terminals of the fifth and eighth IGBTs (36) and (39) and the sixth and seventh IGBTs (37) and (38) of FIG.
Outputs _G3 and V _G4 .

As shown in FIG. 8, the inverter control circuit (4
3) is an output amplitude setting means (44) for outputting an amplitude setting signal V _RA for controlling the amplitude of the AC output voltage V _O output from the inverter circuit (3), and an AC input voltage for the commercial AC power supply (1). A phase-locked oscillator (45) that generates a sine wave signal V _PH synchronized with the phase of V _AC , an amplitude setting signal V _{RA of} the output amplitude setting means (44), and a sine wave signal V _{PH of the} phase locked oscillator (45). third error detecting and multiplying circuit (46) for outputting a product signal V _M2, the level difference between the product signal V _M2 and an AC output voltage V _O supplied to the load (5) of the multiplier circuit (46) of The amplifier (47), the error output signal V _{E3 of} the third error amplifier (47) and the capacitor current detector (42)
Of the fourth error amplifier (48) for detecting the level difference from the detection voltage V _C of the control signal and the switching frequency of the fifth to eighth IGBTs (36) to (39), for example, a reference triangular wave signal V _{T2 of} 20 kHz. Triangular wave oscillator (49) for outputting and fourth error amplifier
A PWM comparator (50) for comparing the error output signal V _E4 of (48) with the reference triangular wave signal V _{T2 of the} triangular wave oscillator (49) to form a PWM modulation signal V _PWM , and a PWM comparator (50)
The third on / off control is performed by adding dead time which is a period during which all the fifth to eighth IGBTs (36) to (39) in the switching circuit (35) are in the off state to the PWM modulation signal V _PWM of A third control signal generating circuit (51) for forming the signal V _G3 , and P
WM comparator (50) of the PWM signal V _PWM inverted signal -V inverter for outputting a _PWM (52), inverter (52) output signal -V _PWM to the dead time added to the 4 of the It is provided with a fourth control signal generating circuit (53) for generating an on / off control signal V _G4 .

The pair of fifth and eighth IGBTs (36) and (39) and the pair of sixth and seventh IGBTs (37) and (38) in the switching circuit (35) are alternately turned on and off. By doing so, the DC voltage V _DC from the converter circuit (2) or the DC voltage V _BT from the battery (4) is converted into an AC voltage,
The AC output voltage V _O is supplied to the load (5) via the filter reactor (40) and the filter capacitor (41). on the other hand,
The sine wave signal V _PH of the phase locked oscillator (45) output from the multiplication circuit (46) and the amplitude setting signal V _{RA of the} output amplitude setting means (44)
AC product voltage V _O of the inverter circuit (3) synchronized with the _AC input voltage V _AC of the commercial AC power supply (1) by the product signal V _M2
Reference signal is formed. The AC output voltage V _O supplied to the load (5) and the product signal V _M2 of the multiplication circuit (46) are respectively the inverting input terminal (−) of the third error amplifier (47) in the inverter control circuit (43). And a non-inverting input terminal (+).
The third error amplifier (47) is provided with the AC output voltage V _O and the product signal V _O.
The level difference from _M2 is detected, and the error output signal V _E3 is output from the output terminal according to the level difference. Third error amplifier
The error output signal V _E3 of (47) is input to the inverting input terminal (−) of the fourth error amplifier (48), and the fourth error amplifier (48)
The level difference between the error output signal V _E3 and the detection voltage V _C of the capacitor current detector (42) input to the non-inverting input terminal (+) is detected, and the error output signal V _E is output from the output terminal according to the level difference. Outputs _E4 .

Error output signal V _{E4 of} the fourth error amplifier (48)
Is compared with the reference triangular wave signal V _{T2 of the} triangular wave oscillator (49) by the PWM comparator (50) and becomes a low level when the relationship between the error output signal V _E4 and the reference triangular wave signal V _T2 is V _E4 > V _T2. , V _E4 <V _T2, the pulse train signal which becomes high level is output from the PWM comparator (50) to form the PWM modulation signal V _PWM . PWM of PWM comparator (50)
The modulation signal V _PWM is directly input to the third control signal generation circuit (51) and is also input to the fourth control signal generation circuit (53) via the inverter (52), and each control signal generation circuit (51),
At (53), the dead time is added to form the third and fourth on / off control signals V _G3 and V _G4 . In the inverter control circuit (43), the AC output voltage V _O supplied to the load (5)
Is higher than the voltage level of the amplitude setting signal V _RA of the output amplitude setting means (44), the third and fourth ON / OFF control signals V _G3 and V _G4 having narrow pulse widths are formed to form the fifth and 8th
IGBTs (36), (39) and sixth and seventh IGBTs (3
The pulse width of the gate output applied to 7) and (38) can be narrowed, whereby the level of the AC output voltage V _O can be reduced. On the other hand, if the level of the AC output voltage V _O supplied to the load (5) is lower than the voltage level of the amplitude setting signal V _RA of the output amplitude setting means (44), the third and fourth ON pulses having a wide pulse width are turned on. Forming off control signals V _G3 and V _G4 to _generate fifth and eighth I
GBTs (36), (39) and sixth and seventh IGBTs (37),
The pulse width of the gate output given to (38) can be widened, whereby the level of the AC output voltage V _O can be increased. Therefore, by the third and fourth on / off control signals V _G3 and V _G4 output from the inverter control circuit (43), the AC output voltage V _O of the load (5) and the capacitor current detector (42) are detected. The fifth and eighth IGBTs (36) and (39) and the sixth and seventh IGBTs (37) and (38) in the inverter circuit (3) are controlled to be turned on / off alternately according to the voltage V _C. The AC output voltage V _O with less voltage fluctuation and distortion is supplied to the load (5) through the filter reactor (40) and the filter capacitor (41).

[0012]

By the way, as shown in FIG.
When diagnosing the life of the battery (4) with the uninterruptible power supply,
For example, the following three methods are possible.   After stopping the converter circuit (2) operation, the battery
Battery measured by discharging from (4) to the inverter circuit (3)
Voltage V of Li (4)_BTAnd current I_BTTo the internal battery (4)
Impedance calculation to determine battery (4) life
It   A in the bypass circuit (10) for bypass power supply
After switching the C switch (11) to the ON state at high speed,
Of the battery (4) when the inverter circuit (2) is stopped.
Discharge voltage V_BTTo determine the life of the battery (4)
It   Ambient temperature of battery (4) detected by thermistor (8)
The digital thermometer (9) to measure the
Judge the life of the terri (4). However, the internal impedance is calculated and the battery
In the method of diagnosing the life of (4), stop the converter circuit (2).
Stop the inverter circuit (3) with the output of the battery (4).
Have to drive. Because of this, the battery life
Discharge voltage V of (4) _BTIf the
The DC voltage required to operate the circuit (3) is insufficient and the inverter
Negative if the battery (4) is at the end of life as the circuit (3) will stop.
There was a drawback that the power supply to the load (5) was stopped. Also,
The discharge voltage of the battery (4) after the inverter circuit (2) has stopped operating.
V_BTThe method of measuring
Current flows from the commercial AC power supply (1) through the bypass circuit (10).
Is supplied directly to the load (5), the life of the battery (4) is checked.
If the commercial AC power supply (1) fails during disconnection, the power to the load (5) will be lost.
There was a drawback that the power supply was stopped. Furthermore, the thermistor (8)
The method of detecting the ambient temperature of the battery (4) by
Because the ambient temperature of the battery (4) fluctuates, the life of the battery (4)
There was a drawback that life could not be accurately diagnosed. In particular,
As a memory power supply that retains the stored contents of data such as
If you use a power supply, even if there is an
Battery may be destroyed or lost
Power supply to the memory stops during the life diagnosis of (4)
Is a fatal drawback.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a battery life diagnosis method for an uninterruptible power supply, which can accurately diagnose the life of a battery without stopping power supply to a load.

[0014]

A battery life diagnosis method for an uninterruptible power supply according to the present invention is a converter circuit (2) for converting AC power from an AC power supply (1) into DC power, and a converter circuit (2). The inverter circuit (3) that converts the DC output of the AC output to the AC output and supplies the AC output to the load (5), and the battery (4 that supplies DC power to the inverter circuit (3) when the AC power supply (1) fails. ) And an uninterruptible power supply unit that controls the DC voltage (V _DC ) of the converter circuit (2) and outputs the DC voltage (V _DC ) output from the converter circuit (2) to the discharge voltage of the battery (4). (V _BT ) to a value lower than (V _BT ) to regenerate the DC power of the battery (4) to the AC power supply (1) via the converter circuit (2), and from the battery (4) via the converter circuit (2). When the current regenerated by the AC power supply (1) and the current supplied from the AC power supply (1) to the converter circuit (2) are balanced Converter circuit (2) of the output voltage (V ₂₎ and a current which is regenerated to the battery (4) from the current flowing in the inverter circuit (3) (I ₄₎ and a battery (4) from the converter circuit (2) (I ₅₎ The process of measuring the sum current (I ₄ + I ₅ ) and the measured output voltage (V ₂ ) and sum current (I ₄ + I ₅ ) of the converter circuit ( ₂ ) and the discharge characteristics of the battery (4) The battery (4) can be discharged from the battery (4)
And determining the lifespan of the.

When the DC voltage (V _DC ) output from the converter circuit (2) is lower than the discharge voltage (V _BT ) of the battery (4), the DC power from the battery (4) flows through the converter circuit (2). Since it is regenerated by the AC power supply (1) via the AC power supply (1), the regenerated current flows from the battery (4) to the AC power supply (1) via the converter circuit (2). Converter circuit when this regenerative current and the current supplied from the AC power supply (1) to the converter circuit (2) are balanced and the input current value of the converter circuit (2) becomes approximately 0
The output voltage (V ₂ ) of ( ₂ ) becomes the discharge voltage (V _BT ) of the battery (4).

The discharge current (I _BT ) of the battery (4) is the current (I ₄ ) flowing from the battery (4) to the inverter circuit (3) and the current regenerated from the battery (4) to the converter circuit (2). Since it is the sum of (I ₅ ), the sum current (I ₄ + I ₅ ) with the output voltage (V ₂ ) of the converter circuit (2) at this time is measured, and these measured values and the battery (4) If the dischargeable time of the battery (4) is obtained from the discharge characteristic of (4), the life of the battery (4) can be determined.

Therefore, it is not necessary to stop the converter circuit (2) at the time of diagnosing the life of the battery (4).
Since the converter circuit (2) supplies the DC power to the inverter circuit (3) even when the battery has reached the end of its life, the power supply to the load (5) does not stop. Further, since it is not affected by the fluctuation of the ambient temperature of the battery (4), the life of the battery (4) can be accurately diagnosed.

Therefore, the life of the battery (4) can be accurately diagnosed without stopping the power supply to the load (5). Furthermore, since the output voltage (V ₂ ) when the input current value of the converter circuit (2) becomes approximately 0 is the discharge voltage (V _BT ) of the battery (4), it is equivalent to the stopped state of the converter circuit (2). Therefore, it becomes possible to obtain a more accurate discharge voltage value of the battery (4).

Specifically, one input terminal of the first error amplifier (24) provided in the converter circuit (2) is connected to the battery.
(4), the setting voltage generating means (54) is connected to the other input terminal of the first error amplifier (24), and the setting voltage generating means (5
The set voltage (V _RD ) of 4) is gradually decreased from a value higher than the discharge voltage (V _BT ) of the battery (4), and the DC voltage (V _DC ) output from the converter circuit (2) is changed to the battery (V _DC ). 4) discharge voltage (V
_BT ).

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a battery life diagnosis method for an uninterruptible power supply according to the present invention will be described below with reference to FIGS.
Will be described. In these drawings, the portions substantially the same as those shown in FIGS. 6 to 8 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 1, the converter circuit (2) constituting the uninterruptible power supply according to the present embodiment is a set voltage generating means (22) in the converter control circuit (21) shown in FIG.
Is characterized in that it is changed to a set voltage generating means (54) having a voltage adjusting means such as a semi-fixed resistor (trimmer resistor). By appropriately adjusting the voltage adjusting means of the setting voltage generating means (54) to adjust the setting voltage V _RD , the converter circuit
It is possible to change the value of the DC voltage V _DC output from (2). The configuration other than the setting voltage generating means (54) is substantially the same as that of the converter circuit (2) shown in FIG. In the converter circuit (2) shown in FIG. 1, when the set voltage V _{RD of} the set voltage generating means (54) is lower than the discharge voltage V _BT of the battery (4),
The first and fourth IGBTs (1
6), (19) and the second and third IGBTs (17), (18) are alternately turned on / off to allow the power on the DC output side to be sent to the AC input side. Therefore, in the normal operation, since the charging power is supplied to the battery (4), the set voltage V _RD of the set voltage generating means (54) is set to a value higher than the discharge voltage V _BT of the battery (4). ing. In addition, the inverter circuit (3) of the present embodiment is similar to FIG.
Since it is substantially the same as the inverter circuit (3) shown in, the illustration is omitted.

Next, the battery of the uninterruptible power supply of this embodiment will be described.
A battery life diagnosis method will be described with reference to FIGS. 2 and 3.
First, the DC voltage V output from the converter circuit (2)_DC
Is the discharge voltage V of the battery (4)_BTIs almost the same as
Switch (23) in the control circuit (21) closes to the contact (A) side.
Output signal V of the first error amplifier (24)_E1Stands for
The set voltage V of the set voltage generating means (54) is set to 0._RDTo
Battery (4) discharge voltage V_BTGradually descend from higher value
Let me down. DC voltage output from converter circuit (2)
V_DCIs the discharge voltage V of the battery (4)_BTIs almost the same as
The current flowing between the converter circuit (2) and the battery (4)
It becomes almost 0, and the discharge current I of the battery (4)_BTIs almost Inva
Converter circuit (3), so the converter circuit at that time
Output voltage V of (2)₁Is the discharge voltage V of the battery (4)_BTTona
It Next, as shown in FIG.
Output voltage V of line (2)₁With a tester (55) and
Current I flowing from battery (4) to inverter circuit (3)₁Electric
Detect with the flow detection probe (56) and measure with the tester (55).
It At the same time, the ambient temperature of the battery (4) at this time
Is detected by the thermistor (8) and is detected by the digital thermometer (9).
taking measurement. After this, the ambient temperature of the battery (4) will be room temperature.
The case of (20 to 25 ° C.) will be described. Then before
Voltage V₁And current I₁And the room temperature (2
From the graph of the discharge characteristics of the battery (4) at 0-25 ° C)
Get the time to discharge the battery (4). In the graph of Figure 3
, The discharge voltage of the battery (4) at room temperature
V_BTThat is, the output voltage of the converter circuit (2) is V₁At room temperature
Battery (4) discharge current I under_BT, Ie battery (4)
Current flowing from the inverter circuit (3) to I₁At the time
The minimum allowable voltage of (4) is V_E= 10V, at room temperature
The battery (4) can be discharged for about 1 hour.
It Generally, the discharge voltage V of the battery (4)_BTIs aging
Gradually decreases with the discharge of the new battery (4)
Battery (4) life when approximately half of the time is available
To judge. Therefore, the battery (4) should be
When the discharge characteristics of the product draw the curve shown in the graph of Fig. 3,
Battery (4) when the dischargeable time reaches 0.5 hours
Is the life of. In the graph of Fig. 3, the two broken lines are the battery
Discharge current I of (4)_BTIs I₂, I₃The characteristic curve when
Shown, each I₂<I ₁<I₃Have a relationship.

As described above, in this embodiment, the DC voltage V _DC output from the converter circuit (2) is supplied to the battery (4).
Discharge voltage V _BT and by substantially the same, the discharge voltage V of the battery (4) by the output voltage V ₁ of the converter circuit (2) at that time
_{Get BT} . Further, at this time, the discharge current I _BT of the battery (4) is obtained from the current I ₁ flowing from the battery (4) to the inverter circuit (3). Then, obtain a dischargeable time of the battery from the discharge characteristic graph of the battery (4) at room temperature shown in the measured value and 3 of these voltages V ₁ and current I ₁ (4). Therefore, it is not necessary to stop the converter circuit (2) when diagnosing the life of the battery (4), and DC power is supplied from the converter circuit (2) to the inverter circuit (3) even when the battery (4) is at the end of life. Therefore, the power supply to the load (5) does not stop. Further, since the service life is not diagnosed by measuring the ambient temperature of the battery (4), the service life of the battery (4) can be accurately diagnosed. If the graph of the discharge characteristics of the battery (4) against the ambient temperature of the battery (4) in the temperature range other than the normal temperature (20 to 25 ° C.) is prepared, the life of the battery (4) can be more accurately diagnosed. .

The embodiment shown in FIG. 2 can be modified. For example, the battery life diagnosis method for an uninterruptible power supply device shown in FIG. 4, a value lower than the discharge voltage V _BT of the DC voltage V _{D C} a battery (4) output from the converter circuit (2),
That is, when the changeover switch (23) in the converter control circuit (21) is closed to the contact (A) side, a set voltage is generated so that the output signal V _E1 of the first error amplifier (24) becomes a negative value. The setting voltage V _RD of the means (54) is gradually decreased from a value higher than the discharge voltage V _BT of the battery (4). When the DC voltage V _DC output from the converter circuit (2) becomes lower than the discharge voltage V _BT of the battery (4), the DC power from the battery (4) is commercial AC power supply via the converter circuit (2). Since it is regenerated to the (1) side, a regenerated current flows from the battery (4) to the commercial AC power supply (1) side via the converter circuit (2). The regenerative current and the current supplied from the commercial AC power supply (1) to the converter circuit (2) are balanced and the value of the _AC input current I _AC of the converter circuit (2), that is, the detection of the input current detector (6) The output voltage V ₂ of the converter circuit (2) when the voltage V _IA becomes approximately 0 V becomes the discharge voltage V _BT of the battery (4). The discharge current I _BT of the battery (4) is the sum of the current I ₄ flowing from the battery (4) to the inverter circuit (3) and the current I ₅ regenerated from the battery (4) to the converter circuit (2). . Therefore, while measuring the output voltage V ₂ of the converter circuit (2) with the tester (55),
The current I ₄ flowing from the battery (4) to the inverter circuit (3) and the current I ₅ regenerated from the battery (4) to the converter circuit (2) are detected by the current detection probe (56), and are detected by the tester (55). taking measurement. At the same time, the ambient temperature of the battery (4) is detected by the thermistor (8) and measured by the digital thermometer (9). After this, the ambient temperature of the battery (4) is at room temperature (2
The case of 0 to 25 ° C. will be described. Then, the measured value of the output voltage V ₂ of the converter circuit (2) and the sum current I ₄ + I ₅ of the respective currents I ₄ and I _{5 and} the room temperature (20 to 25) shown in FIG.
From the discharge characteristic graph of the battery (4) at
To get the dischargeable time of. In the graph of FIG. 5, for example, the discharge voltage V _BT of the battery (4) at room temperature, that is, the output voltage of the converter circuit (2) is V ₂ , and the battery at room temperature is
(4) discharge current I _BT, i.e. the battery (4) the sum current from the current I ₄ and the battery flowing through the inverter circuit (3) (4) and the current I ₅ is regenerated to the converter circuit (2) from the I ₄ of At + I ₅ , if the minimum allowable voltage of the battery (4) is V _E = 10V, the dischargeable time of the battery (4) at room temperature can be read as about 1 hour. Therefore, when the discharge characteristic of the battery (4) at the room temperature at the time of new drawing draws the curve shown in the graph of FIG.
Battery (4) when the dischargeable time reaches 0.5 hours
Is the life of.

As described above, in the embodiment shown in FIG. 4, the DC voltage V _DC output from the converter circuit (2) is set to a value lower than the discharge voltage V _{BT of} the battery (4). DC power from the battery is regenerated from the battery (4) to the commercial AC power supply (1) via the converter circuit (2).
Output voltage V of the converter circuit (2) when the current regenerated by the commercial AC power supply (1) via the (2) and the current supplied from the commercial AC power supply (1) to the converter circuit (2) are balanced ₂ obtains the discharge voltage V _BT of the battery (4). Also batteries (4)
From the current I ₄ flowing through the inverter circuit (3) battery (4)
From the sum current I ₄ + I ₅ with the current I ₅ regenerated in the converter circuit (2), the discharge current I _BT of the battery (4) is obtained. Then, the output voltage V ₂ of the converter circuit (2) and the measured value of the sum current I ₄ + I ₅ of the respective currents I ₄ and I ₅ and the discharge characteristic graph of the battery (4) at room temperature shown in FIG. Obtain the dischargeable time in (4). Therefore, it is not necessary to stop the converter circuit (2) when diagnosing the life of the battery (4).
The power supply to the load (5) does not stop as in the embodiment shown in FIG. Further, since the service life is not diagnosed by measuring the ambient temperature of the battery (4), the service life of the battery (4) can be accurately diagnosed. Therefore, in the embodiment shown in FIG. 4, as in the embodiment shown in FIG. 2, the life of the battery (4) can be accurately diagnosed without stopping the power supply to the load (5). The ambient temperature of the battery (4) is room temperature (20-25
Battery (4) in that temperature range
A more accurate battery can be obtained by preparing a graph of the discharge characteristics of
The life diagnosis of (4) becomes possible. Further, in the embodiment shown in FIG. 4, the current regenerated from the battery (4) to the commercial AC power supply (1) side via the converter circuit (2) and the commercial AC power supply (1)
The output voltage V ₂ when the value of the AC input current I _AC of the converter circuit (2) becomes approximately 0 due to the balance with the current supplied from the converter circuit (2) to the discharge voltage V _{BT of the} battery (4) Therefore, it is equivalent to the stopped state of the converter circuit (2),
A more accurate discharge voltage value of the battery (4) can be obtained.

The embodiments of the present invention are not limited to the above-mentioned embodiments, and various modifications can be made. For example, in each of the above-described embodiments, an IGBT (insulated gate bipolar transistor) having a parasitic diode is used as a switching element forming the converter circuit (2) and the inverter circuit (3). A MOS-FET (MOS type field effect transistor) or the like that it has can be used. If a diode is connected in parallel with the switching element, a junction type bipolar transistor, a J-FET (junction type field effect transistor), a thyristor or the like can be used. Furthermore, in each of the above-described embodiments, the present invention is applied to the uninterruptible power supply for single-phase AC, but also for the uninterruptible power supply for three-phase AC or four-phase or more multi-phase AC. The present invention can be applied.

[0027]

According to the present invention, the life of the battery can be accurately diagnosed without stopping the power supply to the load, so that the maintenance or consumption of the battery can be performed without impairing the function and reliability of the uninterruptible power supply. It becomes possible to exchange the time. In particular, the effect of the present invention is remarkable when an uninterruptible power supply is used as a power supply for holding the stored contents of a memory mounted on a computer or the like.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a converter circuit of an uninterruptible power supply used in each embodiment of the present invention.

FIG. 2 is a block diagram showing a main circuit configuration of an uninterruptible power supply according to an embodiment of the present invention.

FIG. 3 is a graph showing discharge characteristics of the battery of FIG. 2 at room temperature.

FIG. 4 is a block diagram showing a main circuit configuration of an uninterruptible power supply according to another embodiment of the present invention.

FIG. 5 is a graph showing discharge characteristics of the battery of FIG. 4 at room temperature.

FIG. 6 is a block diagram showing a main circuit configuration of a conventional uninterruptible power supply.

FIG. 7 is an electric circuit diagram showing the converter circuit of FIG.

FIG. 8 is an electric circuit diagram showing the inverter circuit of FIG.

[Explanation of symbols]

(1) ・ ・ Commercial AC power supply (AC power supply), (2) ・ ・ Converter circuit, (3) ・ ・ Inverter circuit, (4) ・ ・ Battery, (5) ・ ・ Load, (6) ・ ・ Input current Detector, (7)
..Discharge current detectors, (8) .. Thermistors, (9) ..
Digital thermometer, (10) ・ Bypass circuit, (11) ・
・ AC switch, (12) ・ Breaker, (13) ・ ・ Input capacitor, (14) ・ ・ Reactor, (15) ・ ・ Switching circuit, (16) ・ ・ First IGBT, (16a) ・ ・First
Parasitic diode of (17) .. second IGBT, (17)
a) .. second parasitic diode, (18) .. third IGB
T, (18a) -third parasitic diode, (19) -fourth IGBT, (19a) -fourth parasitic diode,
(20) ・ ・ Smoothing capacitor, (21) ・ ・ Converter control circuit, (22) ・ ・ Set voltage generating means, (23) ・ ・ Switch, (24) ・ ・ First error amplifier, (25) ・・ Proportional integrator, (26) ・ ・ Sine wave generator, (27) ・ ・ Multiplier, (28) ・ ・ Second error amplifier, (29) ・ ・ Triangle wave oscillator, (30) ・ ・ PWM comparator, (31) ... First
Control signal generation circuit, (32) · · Inverter, (33) · · 2nd control signal generation circuit, (34) · · input capacitor,
(35) .. switching circuit, (36) .. fifth IGB
T, (36a) -fifth parasitic diode, (37) -sixth IGBT, (37a) -sixth parasitic diode,
(38) .. 7th IGBT, (38a) .. 7th parasitic diode, (39) .. 8th IGBT, (39a) .. 8th
Parasitic diode of (40), filter reactor, (4
1) ・ ・ Filter capacitor, (42) ・ ・ Capacitor current detector, (43) ・ ・ Inverter control circuit, (44) ・ ・ Output amplitude setting means, (45) ・ ・ Phase synchronous oscillator, (46) ・
・ Multiplication circuit, (47) ・ ・ Third error amplifier, (48) ・ ・
Fourth error amplifier, (49) ・ ・ Triangular wave oscillator, (50) ・
-PWM comparator, (51) -third control signal generation circuit, (52) -inverter, (53) -fourth control signal generation circuit, (54) -set voltage generation means, (55) ) ・ ・ Tester, (56) ・ ・ Current detection probe

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H02J 7/34 H02J 7/34 J 9/06 504 9/06 504A 504B H02M 7/12 H02M 7/12 A 7/48 7 / 48 N (56) Reference JP-A-2-262077 (JP, A) JP-A-8-154345 (JP, A) Patent 2749502 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB) Name) H02J 9/00 H02J 7/00 H02M 7/48 G01R 31/36

Claims (2)

(57) [Claims] 1. A converter circuit for converting AC power from an AC power supply into DC power, an inverter circuit for converting a DC output of the converter circuit into an AC output and supplying the AC output to a load, and an AC power supply of the AC power supply. In a battery life diagnosis method for an uninterruptible power supply device including a battery that supplies DC power to the inverter circuit during a power failure, a DC voltage of the battery is controlled by controlling a DC voltage of the converter circuit. A process of controlling the DC power of the battery to a value lower than a discharge voltage to regenerate the AC power supply through the converter circuit, and a current regenerated from the battery to the AC power supply through the converter circuit and the AC The output voltage of the converter circuit when the current supplied from the power supply to the converter circuit is balanced, and From the battery discharge characteristics of the output voltage of the converter circuit and the measured value of the sum current, and the process of measuring the sum current of the current flowing from the battery to the inverter circuit and the current regenerated from the battery to the converter circuit. And a step of determining the life of the battery based on the obtained time at which the battery can be discharged. 2. An input terminal of a first error amplifier provided in the converter circuit is connected to the battery,
Setting voltage generating means is connected to the other input terminal of the first error amplifier, the setting voltage of the setting voltage generating means is gradually decreased from a value higher than the discharge voltage of the battery, and output from the converter circuit. 2. The method of diagnosing battery life of an uninterruptible power supply according to claim 1, further comprising the step of lowering and holding a direct current voltage lower than a discharge voltage of the battery.