JP2000308359A - Non-break power supply including a battery charging/ discharging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of batteries and simplify the charging/ discharging circuit, by providing a semiconductor switch that is parallel to a converter of a half-bridge type rectifying circuit comprising a DC reactor in the AC power supply side, a battery discharging device of a series capacitor, and a half bridge type inverter with an AC filter. SOLUTION: A half-bridge type rectifying circuit of a reactor 18 connecting one end to an AC power supply and diodes 16, 17 connecting the connecting points of the diodes with the other end is provided to a converter 20. A battery charging part 30 provides a semiconductor switches (IGBT) 1 to 4 provided in parallel with the rectifying circuit and a battery between the connecting points of IGBT 1, 2 and 3, 4. A capacitor 5 is connected in parallel between the cathode of the diode 8 connecting the anode to the collector of IGBT 1 and the connecting points of IGBT 2, 3. A series circuit of the capacitor 6 is provided between the connecting points of IGBT 2, 3 and the anode of diode 9 connecting the cathode to the emitter of IGBT 4, and moreover a half-bridge type inverter an AC filter of reactor 13 and capacitor 14 is also provided to the inverter 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an uninterruptible power supply (hereinafter referred to as UPS) having a battery charging / discharging unit.

[0002]

2. Description of the Related Art FIG. 6 shows an example (a float type) of a UPS having a battery charge / discharge circuit according to a conventional type. 2
A half-bridge rectifier in which two diodes 111 and 112 are connected in series, a reactor 113 in which one end is connected to a connection point of the diodes 111 and 112 and the other end is connected to one end of an AC input power supply 115, and is connected in parallel to the AC input power supply 115 A converter section is constituted by an AC filter including a capacitor 114 that performs the conversion.

[0003] Both ends of the half-bridge rectifier are connected in parallel, and the connection point between the semiconductor switches is connected to an AC power supply 115.
Semiconductor switches 101 and 102 connected to the other end of the
A battery 103 having a positive electrode connected to the collector terminal of the semiconductor switch 101 via a diode 105 and a negative electrode connected to a connection point between the semiconductor switches 101 and 102, and a positive electrode connected to the connection point. Battery 104 having a negative electrode connected to the emitter terminal of semiconductor switch 102 via diode 106
And a series circuit of two DC smoothing capacitors 107 and 108 connected in parallel to both ends of a series circuit of two batteries 103 and 104 and connected to a connection point of the capacitors at a connection point of the batteries. It constitutes a charge / discharge unit.

An inverter in which two semiconductor switches 109 and 110 connected in parallel to both ends of a series circuit composed of capacitors 107 and 108, and a semiconductor switch 1
09 and 110 and capacitors 107 and 1
An inverter section is constituted by a reactor 115 provided between the connection points 08 and an AC filter including a capacitor 116.

[0005] The reactor 113 is a step-up reactor,
The energy stored by turning on the semiconductor switch 101 when the input voltage is a positive half-wave is
01 is turned off, and the battery 103 and the capacitor 107 are charged at the same time. In addition, when the input voltage is a negative half wave, the energy stored by turning on the semiconductor switch 102 is released by turning off the semiconductor switch 102, and the battery 104 and the capacitor 108 are charged simultaneously. That is, each time the polarity of the AC input voltage changes, the semiconductor switches 101 and 102 are alternately turned on and off to control the battery 103 and the capacitor 107.
Alternatively, the battery 104 and the capacitor 108 are charged alternately.

When the AC power supply fails, the battery 1
03 is stored in the capacitor 107,
The charging energy of the battery 104 is
Is accumulated in Semiconductor switch 1 constituting inverter
When ON and OFF of 09 and 110 are alternately controlled, the energy stored in the capacitors 107 and 108 is converted into AC power, and is transmitted through a filter circuit including the reactor 116 and the capacitor 117.

[0007]

In a UPS provided with a battery charging / discharging circuit of the float type, two sets of batteries are required, and therefore, the size of the UPS is large and the price is high. Further, the chopper method not only complicates the circuit configuration, but also has a drawback that the upper and lower DC voltages cannot be balanced at the time of battery discharge.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and has reduced the number of batteries and simplified the structure of a battery charge / discharge circuit. Also, as shown in the second embodiment,
By providing a reactor on the positive electrode side of the battery, a battery charge / discharge circuit using a step-up / step-down chopper method was configured.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a circuit configuration of a UPS including a battery charging unit according to a first embodiment of the present invention, which is configured by a converter unit 20, a battery charging / discharging unit 30, and an inverter unit 40.

The converter section 20 is constituted by a reactor 18 having one end connected to an AC power supply and a half-bridge rectifier circuit including two diodes 16 and 17 having a connection point between the diodes at the other end.

The battery charge / discharge unit 30 includes a series circuit including semiconductor switches (hereinafter, referred to as IGBTs) 1 to 4 connected in parallel to both ends of the half-bridge rectifier circuit,
A battery 7 connected in parallel between the connection point of the IGBTs 1 and 2 and a connection point of the IGBTs 3 and 4 is connected in parallel between the cathode terminal of the diode 8 having the anode terminal connected to the collector terminal of the IGBT 1 and the connection point of the IGBTs 2 and 3. And a series circuit of two capacitors including a capacitor 6 connected in parallel between a connection point of the IGBTs 2 and 3 and an anode terminal of a diode 9 having a cathode terminal connected to an emitter terminal of the IGBT 4. ing.

The inverter section 40 includes IGBTs 11 and 1 connected in parallel to both ends of a series circuit comprising capacitors 5 and 6.
And an IGB
An AC filter including a reactor 13 and a capacitor 14 is provided between a connection point between T11 and T12 and a connection point between capacitors 5 and 6.

Next, the circuit operation in the first embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows the circuit operation when the battery is charged.
3A and 3B show the case where the input voltage is positive, and FIGS. 3C and 3D show the case where the input voltage is negative. FIG. 5 shows a circuit operation when the battery is discharged during a power failure.

When the input voltage is a positive half wave, the IGBT 1
At the same time as energy is stored in the reactor 18 due to a short circuit due to the simultaneous ON of
A battery voltage is applied to the capacitor 6 via the GBT 2, the capacitor 6, the diode 9, and the freewheeling diode of the IGBT 4. Next, when the IGBT 1 is turned on and the IGBT 2 is turned off, the energy stored in the reactor 18 charges the capacitor 5 via the diodes 16 and 8. In addition, the energy of the reactor 18 charges the battery 7 via the reflux diode of the diode 16, the IGBT1, the battery 7, and the IGBT3. FIG. 3 (e) is the same as FIG.
(A) and shown in _{(b) IGBT1 (S 1)} ~IGBT4
The switching operation of (S ₄ ) is shown. For example, _{Tr of} S ₂
And OFF indicates when the IGBT 2 (S ₂₎ is turned on and off, _{D i} of S ₃ indicates that a current flows through the freewheeling diode of IGBT3 (S _3).

When the input voltage is a negative half wave, the IGBT 3
When energy is stored in the reactor 18 due to a short circuit caused by the simultaneous turning on of
A battery voltage is applied to the capacitor 5 via the freewheeling diode of the GBT 1, the diode 8, the capacitor 5, and the IGBT 3. Next, when the IGBT 3 is turned off and the IGBT 4 is turned on, the energy stored in the reactor 18 charges the capacitor 6 via the capacitor 6, the diodes 9 and 17, and the reactor 18. Also, the freewheeling diode of the IGBT2,
The energy of the reactor 18 via the battery 7, the IGBT 4 and the diode 17 charges the battery 7.
FIG. 3F shows the IGB shown in FIGS. 3C and 3D.
Showing a switching operation of the _{T1 (S 1) ~IGBT4 (S} 4).

When a power failure occurs, the IGBTs 2 and 3 are alternately turned on and off so that the charging energy of the battery 7 is discharged via the capacitors 5 and 6. IGBT3
Is ON, a battery voltage is applied to the capacitor 5 via the battery 7, the freewheeling diode of the IGBT1, the diode 8, the capacitor 5, and the IGBT3. IGB
When T2 is on, the battery voltage is applied to the capacitor 6 via the battery 7, the IGBT2, the capacitor 6, the diode 9, and the freewheeling diode of the IGBT4.
(See FIGS. 5A and 5B.) FIG. 5C shows the IGB when the battery is discharged.
Showing a switching operation of the _{T1 (S 1) ~IGBT4 (S} 4).

The IGBTs 11 and 12 constituting the half-bridge type inverter circuit are the IGBs of the battery charging / discharging unit.
Irrespective of the switching operation of T1 to T4, on / off control is performed alternately during charging and discharging of the battery, and DC power is converted into AC power through capacitors 5 and 6 to obtain AC power.
Send out through a filter.

The circuit configuration of the second embodiment of the present invention is as shown in FIG. 2, and is the same as that of the first embodiment except that a reactor 10 is provided on the positive electrode side of the battery 7. The circuit operation in the second embodiment is shown in FIG.
This will be described with reference to FIG. 4A and 4B show the case where the input voltage has a positive half-wave, and FIGS. 4C and 4D show the case where the input voltage has a negative half-wave. When charging the battery, the reactor 10 functions as a step-down reactor, so that the battery voltage can be set low. When discharging the battery, the reactor 10 is a boost reactor, so that the battery discharge voltage can be increased. As is clear from FIG. 4E, when the input voltage is a positive half-wave, the IGBT 1 is turned on / off so as to control the battery charging at a constant current. Further, as shown in FIG. 4F, when the input voltage is a negative half-wave, the IGBT 4 is turned on / off so as to control the battery charging at a constant current.

[0019]

As described above, the UPS having the battery charging / discharging unit according to the present invention can balance the upper and lower DC voltages at the time of discharging the battery and can reduce the number of batteries, thereby simplifying the circuit configuration. Therefore, the number of parts is small, so that downsizing and cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a UPS including a battery charge / discharge unit according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of a UPS including a battery charge / discharge unit according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of a circuit operation at the time of charging the battery in the first embodiment.

FIG. 4 is an explanatory diagram of a circuit operation at the time of charging a battery in a second embodiment.

FIG. 5 is an explanatory diagram of a circuit operation at the time of battery discharge.

FIG. 6 shows a conventional U having a battery charging / discharging unit.
FIG. 2 is a block diagram showing a circuit configuration of a PS.

[Explanation of symbols]

 1-4,11,12 Semiconductor switch (IGBT) 7 Battery 10,13,18 Reactor 5,6,14 Capacitor 8,9,16,17 Diode

Claims (2)

[Claims] 1. A half-bridge rectifier circuit in which two diodes (16) and (17) are connected in series, and a reactor that connects in series between a connection point between the diodes (16) and (17) and one end of an AC power supply. And (4) a parallel connection between both ends of the half-bridge rectifier circuit.
A series circuit composed of two semiconductor switches (1), (2), (3) and (4), a connection point between the semiconductor switches (1) and (2) and a connection point between the semiconductor switches (3) and (4). A battery (7) provided between the AC power supply and a diode (8) having a collector terminal connected to the anode terminal of the semiconductor switch (1) and a semiconductor switch (2) connected to the other end of the AC power supply. And a capacitor (5) connected in parallel between the point and a diode (9) having a cathode terminal connected to the emitter terminal of the semiconductor switch (2) and the emitter terminal of the semiconductor switch (4). A battery charging / discharging unit configured by a series circuit of two capacitors including a capacitor (6) connected in parallel; and two semiconductor switches (parallel connected to both ends of the series circuit of the two capacitors). A half-bridge type inverter circuit composed of 11) and (12); and a semiconductor switch (1).
A battery charging unit comprising an inverter unit constituted by a reactor (13) and an AC filter comprising a capacitor (14) provided between a connection point between 1) and (12) and a connection point between capacitors (5) and (6). Uninterruptible power supply with discharge unit. 2. A reactor (10) is provided between a connection point between the semiconductor switches (1) and (2) constituting a battery charging / discharging unit and a positive electrode of the battery (7). An uninterruptible power supply comprising the battery charge / discharge unit according to claim 1.