JP5771116B2 - Uninterruptible power system - Google Patents

Description

  The present invention relates to an uninterruptible power supply, and more particularly to an uninterruptible power supply that can simplify the configuration.

  In modern society, the IT system is important as an infrastructure, and the suspension of the IT system due to the loss of commercial power has a great impact on the continuity of social activities.

  Therefore, in preparation for the loss of commercial power, the number of uninterruptible power supply devices installed in servers that are the center of the IT system is increasing, and many uninterruptible power supply devices have already been proposed (for example, Patent Document 1). reference).

  Most uninterruptible power supply units are usually configured to supply power from a commercial power source to the load, and to convert the power stored in the secondary battery into alternating current by an inverter and supply the load to the load at the time of a power failure ing.

JP 2011-97676 A

  However, many conventional uninterruptible power supplies use a switch to switch between commercial power and power supplied from an inverter, which requires higher switch speed, synchronous switching, etc., making the configuration of the uninterruptible power supply more complicated It was inevitable to do.

  Furthermore, parallel connection of a plurality of uninterruptible power supply units, cooperative operation with private power generation facilities, and the like often involve difficulties.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an uninterruptible power supply device that can simplify the configuration and can easily be used in combination with another power source.

  The uninterruptible power supply according to the present invention includes a first secondary battery, a second secondary battery connected in series with the first secondary battery, the first secondary battery, and the second secondary battery. A charger for charging the secondary battery with commercial AC power, and a half for generating AC power synchronized with the commercial AC power from the DC power supplied by the first secondary battery and the second secondary battery A bridge type inverter; and an AC power combining unit that combines the commercial AC power and the AC power generated by the half bridge type inverter with a coupling capacitor.

The uninterruptible power supply according to the present invention is
The charging circuit includes a primary winding, a first secondary winding, and a second secondary winding, and the primary winding is excited by the commercial AC power; A first diode that rectifies AC power generated in the first secondary winding and a second diode that rectifies AC power generated in the second secondary winding;
The half-bridge inverter includes a first switching element having a cathode terminal connected to a positive electrode of the first secondary battery, and a second switching having an anode terminal connected to a negative electrode of the first secondary battery. A choke coil having one terminal connected to a connection point of an element, an anode terminal of the first switching element and a cathode terminal of the second switching element, and the other terminal of the choke coil connected to one terminal And the other terminal includes an integrating capacitor connected to a coupling point between the negative electrode of the first secondary battery and the positive electrode of the second secondary battery,
The AC power combiner includes a commercial power coupling capacitor having one terminal connected to one pole of the commercial AC power supply, and an inverter coupling capacitor having one terminal connected to one terminal of the integrating capacitor Including
The connection point between the other terminal of the commercial power supply coupling capacitor and the other terminal of the inverter coupling capacitor is one output terminal, and the other terminal of the integrating capacitor is the other output terminal. ing.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to simplify a structure, the uninterruptible power supply device which can implement | achieve combined use with another power supply easily is realizable.

It is a lineblock diagram of the uninterruptible power supply concerning the present invention. It is a voltage waveform figure of the AE point of the uninterruptible power supply concerning the present invention. It is an equivalent circuit diagram for demonstrating the operation state of a half bridge type inverter.

  Embodiments of an uninterruptible power supply according to the present invention will be described below with reference to the drawings.

  That is, the uninterruptible power supply 1 according to the present invention includes a first secondary battery 11 and a second secondary connected in series with the first secondary battery 11 as shown in the configuration diagram of FIG. The battery 12 is supplied by a charger 13 that charges the first secondary battery 11 and the second secondary battery 12 with commercial AC power, and the first secondary battery 11 and the second secondary battery 12. A half-bridge inverter 14 that generates AC power synchronized with commercial AC power from DC power, and an AC power combining circuit 15 that combines commercial AC power and AC power generated by the half-bridge inverter 14 with a coupling capacitor. It is configured.

  The first secondary battery 11 and the second secondary battery 12 are, for example, lithium batteries, and each output 144 volt DC power in which 12 12 volt cells are connected in series.

  The charger 13 includes a relay 131, a charger transformer 132, a charging current measuring circuit 133, a first diode 134 and a second diode 135.

  The charger transformer 132 has one primary winding and two secondary windings.

  One end of the primary winding is connected to one terminal of the commercial power supply via the relay 131, and the other end of the primary winding is connected to the other terminal (ground side) of the commercial power supply via the charging current measuring circuit 133. Has been.

  The anode electrode of the first diode 134 is connected to one end of the first secondary winding, and the anode electrode of the second diode 135 is connected to one end of the second secondary winding.

  The cathode electrode of the first diode 134 is connected to the positive electrode of the first secondary battery 11, and the cathode electrode of the second diode 135 is connected to the positive electrode of the second secondary battery 12.

  Further, the other end of the first secondary winding is connected to the negative electrode of the first secondary battery 11, and the other end of the second secondary winding is connected to the negative electrode of the second secondary battery 12.

  The negative electrode of the first secondary battery 11 and the positive electrode of the second secondary battery 12 are commonly grounded.

  The half-bridge inverter 14 includes a first switching element 141, a second switching element 142, a choke coil 143, an integrating capacitor 144, a switching control circuit 145, and a phase detection transformer 146.

  As the first switching element 141 and the second switching element 142, for example, a MOS-FET can be applied.

  The source terminal of the first switching element 141 is connected to the positive electrode of the first secondary battery 11, the drain terminal of the second switching element 142 is connected to the negative electrode of the second secondary battery 12, and the first switching element 141. The drain terminal and the source terminal of the second switching element 142 are commonly connected to one terminal of the choke coil 143.

  The other terminal of the choke coil 143 is connected to one terminal of the integrating capacitor 144, and the other terminal of the integrating capacitor 144 is grounded.

  The switching control circuit 145 supplies a switching signal synchronized with the commercial power source detected by the phase detection transformer 146 to the gate terminals of the first switching element 141 and the second switching element 142.

  The AC power combining circuit 15 includes a commercial power supply coupling capacitor 151 and an inverter coupling capacitor 152.

  One terminal of the commercial power supply coupling capacitor 151 is connected to one terminal of the commercial power supply, and one terminal of the inverter coupling capacitor 152 is connected to the choke coil 143 that is one terminal of the output of the half-bridge inverter 14. The other terminal is connected to the connection point of one terminal of the integrating capacitor 144.

  The other terminal of the commercial power supply coupling capacitor 151 and the other terminal of the inverter coupling capacitor 152 are connected in common to serve as one terminal of the output of the uninterruptible power supply 1 according to the present invention. The other terminal of the output of the uninterruptible power supply 1 according to the present invention is a ground terminal.

  The operation of the uninterruptible power supply according to the present invention will be described below.

  FIG. 2 is a voltage waveform diagram at points A to E of the uninterruptible power supply shown in FIG. 1, and the waveform at point A is the waveform of the commercial power supply.

  In the charging current measuring circuit 133 of the charger 13, when the first secondary battery 11 and the second secondary battery 12 can be charged, that is, when the charging current is more than a predetermined value, the relay 131 is connected. And commercial power is supplied to the primary winding of the charger transformer 132.

  AC power of a voltage capable of charging the first secondary battery 11 and the second secondary battery 12 is induced in the two secondary windings of the charger transformer 132, and the first diode 134 and the second diode A half-wave rectification is performed by 135.

  The first secondary battery 11 is charged by the DC power output from the first diode 134, and the second secondary battery 12 is charged by the DC power output from the second diode 135.

  If the first secondary battery 11 and the second secondary battery 12 are fully charged, the charging current becomes a predetermined value or less, and the charging current measuring circuit 133 opens the relay 131 and the first 2 The secondary battery 11 and the second secondary battery 12 are prevented from being overcharged.

  The switching control circuit 145 of the half-bridge inverter 14 controls the first switching element 141 and the second switching element 142 in synchronization with the phase of the commercial power supply detected by the phase detection transformer 146, Synchronized AC power is generated.

  FIG. 3 is an equivalent circuit diagram for explaining the operating state of the half-bridge inverter 14, and there are four operating states.

  (A) The first switching element 141 is in the connected state, the second switching element 142 is in the open state, and the current flows from the positive electrode of the first secondary battery 11 through the first switching element 141 and the choke coil 143. It flows into the integrating capacitor 144 and returns to the negative electrode of the first secondary battery 11.

  (B) is a state in which the first switching element 141 shifts to the open state and the second switching element 142 maintains the open state, and the function of maintaining the current of the choke coil 143 allows the second switching element to be switched. The body diode contained in the element 142 is turned on, and a commutation current flows.

  (C) shows that the first switching element 141 is in the open state and the second switching element 142 is in the connected state, and current flows from the positive electrode of the second secondary battery 12 into the integrating capacitor 144, and the choke coil 143 and the second It returns to the negative electrode of the second secondary battery 12 through the second switching element 142.

  (D) is a state in which the first switching element 141 is maintained in the open state and the second switching element 142 is shifted to the open state, and the function of maintaining the current of the choke coil 143 is used to maintain the first switching element 141. Turns on the body diode built in, and commutation current flows.

  The switching control circuit 145 supplies a switching control signal to the gates of the first switching element 141 and the second switching element 142, and performs PWM (pulse width modulation) control on the first switching element 141 and the second switching element 142. To do.

  That is, the switching control circuit 145 outputs a switching control signal whose pulse width is controlled as a switching control signal.

  As a result, the current flowing through the first switching element 141 or the second switching element 142 has a pulse width that increases or decreases in proportion to the sinusoidal voltage of the commercial power supply.

  Since this pulsed current is integrated by the integration capacitor 144, AC power synchronized with the commercial power supply is generated at both ends of the integration capacitor 144.

  The switching control circuit 145 starts to operate when the output voltage of the phase detection transformer 146 falls below a predetermined value.

  In the AC power synthesizing circuit 15, the commercial power is removed from the commercial power by the coupling capacitor 151 for commercial power, and the direct current component is removed from the AC power generated by the half-bridge inverter 14 by the coupling capacitor 152 for inverter. The AC power generated by the bridge inverter 14 is combined.

  When the commercial power supply is normal, the output voltage of the phase detection transformer 146 is greater than a predetermined value, and the half-bridge inverter 14 does not operate.

  As a result, the commercial power is output from the AC power combining circuit 15 as it is.

  Conversely, when the voltage of the commercial power supply drops below a predetermined voltage, the output voltage of the phase detection transformer 146 becomes below a predetermined value, and the half bridge inverter 14 operates to generate AC power.

  Since the AC power generated by the half-bridge inverter 14 is synchronized with the commercial power supply power, no instantaneous power interruption occurs during the transition from the commercial power supply to the inverter power supply.

  It is obvious that no instantaneous interruption occurs when the voltage of the commercial power supply is restored.

  The uninterruptible power supply 1 according to the present invention may include a load current measurement circuit 16 that flows through a load connected to the uninterruptible power supply 1.

  The load current measuring circuit 16 lights a green light when the uninterruptible power supply 1 according to the present invention outputs commercial power, and outputs the AC power generated by the half-bridge inverter 14. Light for yellow.

  When the AC power generated by the half-bridge inverter 14 drops below a predetermined value, a red lamp is lit to warn the user that the secondary battery will be overdischarged.

  In the above embodiment, the case where the first secondary battery 11 and the second secondary battery 12 are charged with commercial power is described. However, it is also possible to charge with a DC power source such as a solar battery or a wind power generator. Obviously.

  Furthermore, in the AC power combining circuit 15, it is also clear that AC power supplied from other AC power sources such as other uninterruptible power supply devices and private power generators can be easily combined via a coupling capacitor.

  INDUSTRIAL APPLICATION While this invention can simplify the structure of an uninterruptible power supply device, it can implement | achieve combined use with another power supply easily, and is industrially useful.

DESCRIPTION OF SYMBOLS 1 Uninterruptible power supply 11 First secondary battery 12 Second secondary battery 13 Charger 14 Half-bridge inverter 15 AC power combiner circuit 16 Load current measurement circuit 131 Relay 132 Charger transformer 133 Charge current measurement circuit 134 First 1 diode 135 second diode 141 first switching element 142 second switching element 143 choke coil 144 integration capacitor 145 switching control circuit 146 phase detection transformer 151 commercial power supply coupling capacitor 152 inverter coupling capacitor

Claims (1)

A first secondary battery;
A second secondary battery connected in series with the first secondary battery;
A charger for charging the first secondary battery and the second secondary battery with commercial AC power;
A half-bridge inverter that generates AC power synchronized with the commercial AC power from DC power supplied by the first secondary battery and the second secondary battery;
Look including a an AC power combiner for combining by the commercial AC power and the half-bridge inverter coupling capacitor AC power generated by,
The charger is
A charger transformer having one primary winding, a first secondary winding and a second secondary winding, wherein the primary winding is excited by the commercial AC power;
A first diode that rectifies AC power generated in the first secondary winding and a second diode that rectifies AC power generated in the second secondary winding;
The half-bridge inverter is
A first switching element having a source terminal connected to a positive electrode of the first secondary battery;
A second switching element having a drain terminal connected to the negative electrode of the first secondary battery;
A choke coil having one terminal connected to a connection point between the drain terminal of the first switching element and the source terminal of the second switching element;
An integrating capacitor connected to the connection point between the negative terminal of the first secondary battery and the positive terminal of the second secondary battery, the other terminal of the choke coil being connected to one terminal; Including
The AC power combining unit is
A commercial power coupling capacitor having one terminal connected to one pole of a commercial power source for supplying the commercial AC power;
Including an inverter coupling capacitor having one terminal connected to one terminal of the integrating capacitor;
An uninterruptible power supply in which the connection point of the other terminal of the coupling capacitor for commercial power supply and the other terminal of the coupling capacitor for inverter is one output terminal, and the other terminal of the integrating capacitor is the other output terminal apparatus.

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