JPH10341539A - Charging and discharging device for storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging and discharging device for storage battery, which has a simple structure, and high charging and discharging efficiency for a storage battery. SOLUTION: The primary side of single-phase transformers 4a-4b of a three- phase transformer 4 is connected to the output terminals U-W of the respective phases of a three-phase AC system 5 respectively, and single-phase bidirectional converters 3a-3c are connected to its secondary side respectively. Storage batteries 2a-2c are connected to the single-phase bidirectional converters 3a-3c, so that the single-phase bidirectional converters 3a-3c conduct charging and discharging for the storage batteries 2a-2c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a battery charging / discharging device, and more particularly, to a battery charging / discharging device using a three-phase AC system.

[0002]

2. Description of the Related Art In recent years, lithium ion secondary batteries have been widely used as storage batteries (secondary batteries). Such a lithium ion secondary battery is a battery system using a carbon material or a transition metal cargokenite in which lithium ions are present in the negative electrode, instead of using metallic lithium as in a conventional lithium battery for the negative electrode. In this type of battery, a coin-type battery using vanadium pentoxide (V ₂ O ₅ ) as a positive electrode and carbon (C) as a negative electrode was commercialized in 1989, and a cylindrical battery in 1991 was used. In recent years, lithium cobalt oxide (LiCoO ₂ ) / carbon (C) batteries have been put into practical use, and research and development are being actively conducted along with business development.

[0003] A lithium ion secondary battery has an operating voltage that is about three times that of a conventional NiCd battery or nickel-metal hydride battery, which is a power supply for driving portable electronic equipment.
It has high volumetric energy density and about twice the energy density by weight. That is, when compared with batteries having the same energy, the batteries are small and light. In particular, taking advantage of this light feature, lithium ion secondary batteries have been adopted as power supplies for driving cellular phones, video cameras, and notebook computers.

[0004] In a storage battery such as a lithium ion secondary battery that operates as a storage battery bank, the storage batteries cannot be directly connected in parallel when charging and discharging. Parallel connection for increasing the storage battery capacity is an effective means, but cannot be directly connected in parallel.
Japanese Utility Model Publication No. Hei 5-37637 discloses a charge / discharge device for a storage battery that operates in parallel with a storage battery bank via a converter as shown in FIG.

In the charging / discharging device for a storage battery shown in FIG.
When the battery (storage battery) 6 is divided into a plurality of sets 6a to 6n, contactors 7a to 7n are connected to each set of batteries, and when the movable piece of each contactor is connected to the contact A side, charging through the converter 8 Alternatively, a full discharge mode is set, and when connected to the contact B side, charging / discharging is performed as a discharge mode to a load through the inverter 9. However, in such a device, the charging efficiency of the storage battery is reduced because the efficiency of the converter is added to the charging and discharging of the storage battery.

Further, in the above-mentioned publication, a charging / discharging device for a storage battery in which a parallel conversion device is connected to a storage battery bank and a bidirectional conversion device for system connection is connected at a subsequent stage as shown in FIG. 3 is proposed. . In the battery charging / discharging device shown in FIG. 3, batteries (storage batteries) 6a to 6n are divided into an arbitrary number of sets, each negative electrode side is commonly connected, and each positive electrode side is individually connected to diodes D1 to D1. The anode of Dn is connected. The power conversion device PC is connected to each diode D1.
To Dn are connected between the commonly connected cathode side and the battery negative electrode, and have a function of converting DC to AC and a function of converting AC to DC. Th1 to Thn are charging semiconductor switches connected in anti-parallel to the diodes D1 to Dn, respectively, in which a thyristor is used. T1 to Tn are full-discharge semiconductor switches composed of, for example, thyristors. The anodes of the switches T1 to Tn are connected to the positive electrodes of the batteries 6a to 6n, respectively, and the cathodes are connected in common to the negative side of the converter C. It is connected. The positive side of converter C is connected to the negative side of the battery.

In the device configured as described above, the charging of the batteries 6a to 6n is performed by using the power conversion device PC as a converter function and the charging semiconductor switches Th1 to Thn.
Is turned on, the load side (charging side) → the power converter PC → the charging semiconductor switches Th1 to Thn → the batteries 6a to 6n → the closed loop of the power converter PC is formed, and each battery is charged. However, even with such an apparatus, there is a problem that the efficiency of the entire apparatus is reduced because two sets of the conversion apparatus are passed.

[0008]

That is, in the conventional battery charging / discharging device shown in FIGS. 2 and 3, the efficiency of the converter is added to the charging / discharging of the battery as described above, and the charging of the battery is performed. There is a problem that efficiency is reduced. In other words, when the parallel connection of the storage batteries is connected by a DC bus, there is a problem that a loss occurs between the storage battery and the parallel connection converter, and both the charging efficiency and the discharge efficiency of the storage battery decrease.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a storage battery charging / discharging device having a simple configuration and high charging efficiency and discharging efficiency for the storage battery.

[0010]

According to the charging / discharging apparatus for a storage battery of the present invention, a voltage output terminal of each phase of a three-phase AC system is connected to a primary side thereof, and a voltage of each phase of the three-phase AC system is connected. The three-phase transformer is connected to the three-phase transformer, which converts the voltage for each of the AC voltages of the respective phases input from the output terminals and outputs the converted AC voltage from the secondary side thereof, and the secondary side of the three-phase transformer. Connected to each of the plurality of sets of storage batteries, converts the converted AC voltage of each phase input from the three-phase transformer into DC voltages, and supplies and supplies the DC voltages to the storage batteries. The above object is attained by providing a single-phase bidirectional conversion means comprising a plurality of sets of single-phase direction conversion devices for performing discharge.

That is, according to the battery charging / discharging device of the present invention, the three-phase transformer converts the voltage for each AC voltage of each phase input from the voltage output terminal of each phase of the three-phase AC system. Each of them is output from its secondary side as an AC voltage, and the single-phase bidirectional conversion means comprises a plurality of sets of single-phase direction conversion devices
The conversion AC voltage of each phase input from the three-phase transformer is converted into a DC voltage, and the DC voltage is supplied to a plurality of sets of storage batteries to charge or discharge.

Therefore, according to the storage battery charging / discharging device of the present invention, it is possible to provide a storage battery charging / discharging device with a simple configuration and high device efficiency (high charging efficiency and discharging efficiency). In addition, since a plurality of single-phase bidirectional converters are used to charge and discharge a storage battery by outputting a three-phase AC voltage, each single-phase bidirectional converter independently charges or discharges a storage battery. A discharging operation can be performed. Further, a plurality of sets of storage batteries are configured to be connected to a three-phase AC system via a plurality of single-phase bidirectional converters, so that three sets of storage batteries are connected in parallel to the three-phase AC system. The same capacity is charged and discharged to each of the storage batteries. Further, according to the present invention, the charging or discharging operation at the time of imbalance, which is a drawback of three-phase alternating current, is also a stable operation.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a storage battery charge / discharge device to which the present invention is applied.

More specifically, FIG. 1 is a diagram showing a circuit configuration of a battery charging / discharging device according to the present embodiment.

The battery charging / discharging device 1 includes three sets of storage batteries (battery banks) 2a to 2c, three sets of single-phase bidirectional converters 3a to 3c, a three-phase transformer 4, and a three-phase AC system. And 5.

In the three-phase AC system 5, the output terminals U to W of each phase of the three-phase AC voltage are connected to the single-phase transformers 4a to 4a of the three-phase transformer 4.
4c, and outputs the AC voltage of each phase of the three-phase AC voltage from the output terminals U to W to the primary sides of the single-phase transformers 4a to 4c of the three-phase transformer 4, respectively.

The three-phase transformer 4 comprises single-phase transformers 4a to 4b, and the primary sides of the single-phase transformers 4a to 4b are connected to output terminals U to W of a three-phase AC system 5. The secondary side is connected to the single-phase bidirectional converters 3a to 3c. Each of the single-phase transformers 4a to 4b converts the AC voltage input from the output terminals U to W of the three-phase AC system 5 into an AC voltage corresponding to the winding ratio of the coil, and obtains a conversion. The AC voltage is converted to a single-phase bidirectional converter 3a.
To 3c.

The single-phase bidirectional converters 3a to 3c are respectively
One side is connected to the storage batteries 2a to 2c, and the other side
It is connected to the secondary side of each single-phase transformer 4a to 4c of the phase transformer 4. Then, the single-phase direction change devices 3a to 3c
The conversion AC voltage input from the secondary side of each of the single-phase transformers 4a to 4c of the phase transformer 4 is converted into a DC voltage, and the DC voltage is supplied to each of the storage batteries 2a to 2c. 2b is charged or discharged. The charge or discharge operation is switched by a charge / discharge switch (not shown).

The storage batteries 2a to 2c are, for example, lithium-ion batteries.
The storage batteries 2a to 2c are connected to single-phase bidirectional conversion circuits 3a to 3c, respectively.

Next, the charging / discharging operation of the charging / discharging device 1 for a storage battery configured as described above will be described.

First, from the three-phase AC system 5, three-phase AC voltages are output from output terminals U to W for each phase to the primary side of each of the single-phase transformers 4a to 4c of the three-phase transformer 4. You.

In each of the single-phase transformers 4a to 4b of the three-phase transformer 4, an AC voltage input from each of the output terminals 5a to 5c of the three-phase AC system 5 is supplied with an AC voltage corresponding to the winding ratio of the coil. The converted AC voltage is converted into a voltage, and the obtained converted AC voltage is output from the secondary side to each of the single-phase bidirectional converters 3a to 3c.

In the single-phase bidirectional converters 3a to 3c, converted AC voltages input from the secondary sides of the single-phase transformers 4a to 4b of the three-phase transformer 4 are converted into DC voltages, respectively.
When the charging mode is selected by a charging / discharging changeover switch (not shown), the converted DC voltage is output to the positive electrodes of the storage batteries 2a to 2c, and the charging operation of the storage batteries 2a to 2b is performed. When the discharge mode is selected by the discharge changeover switch, the converted DC voltage is applied to the storage batteries 2a to 2a.
The signal is output to the negative electrode side of c to perform a discharging operation.

As described above, in this embodiment,
Each of the output terminals U to W of each phase of the three-phase AC system 5 has three terminals.
Connect the primary sides of the single-phase transformers 4a to 4b of the phase transformer 4,
Single-phase bidirectional converters 3a to 3c are connected to the secondary sides thereof, storage batteries 2a to 2c are connected to these single-phase bidirectional converters 3a to 3c.
3c are configured to charge and discharge the power storage locations 2a to 2c, so that the storage battery banks can be connected in parallel, and there is no need to use a conversion device for performing the parallel connection. It is possible to provide a storage battery charge / discharge device with high efficiency (high charge efficiency and high discharge efficiency).

Further, since the storage battery of the three-phase AC output is charged and discharged using three single-phase bidirectional converters, the DC part can be divided into three sets of storage battery parts insulated. . As a result, the charging or discharging operation can be independently performed on the storage battery for each single-phase bidirectional converter, thereby improving the usability.

Since the three sets of storage battery banks are connected to the three-phase system AC via three sets of single-phase bidirectional converters, three sets of storage batteries are connected in parallel to the three-phase AC system. The same capacity is charged / discharged in each of the storage batteries.

In this embodiment, the charging or discharging operation at the time of imbalance, which is a drawback of three-phase alternating current, is also a stable operation.

[0028]

According to the storage battery charge / discharge device of the present invention, it is possible to provide a storage battery charge / discharge device with a simple configuration and high device efficiency (high charge efficiency and discharge efficiency). In addition, since the storage battery is charged and discharged by outputting a three-phase AC voltage by using a plurality of single-phase bidirectional converters, the storage battery is independently charged for each single-phase bidirectional converter. Alternatively, a discharging operation can be performed. Also, since a plurality of sets of storage batteries are configured to be connected to a three-phase AC system via a plurality of single-phase bidirectional converters,
Each storage battery is charged and discharged with the same capacity as when three sets of storage batteries are connected in parallel to the phase AC system. Further, according to the present invention, the charging or discharging operation at the time of imbalance, which is a drawback of three-phase alternating current, is also a stable operation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a circuit configuration of a storage battery charge / discharge device according to an embodiment.

FIG. 2 is a first diagram showing a conventional battery charging / discharging device.

FIG. 3 is a second diagram showing a conventional battery charging / discharging device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 charging / discharging device for storage battery 2 storage battery 3 single-phase bidirectional converter 4 three-phase transformer 5 three-phase AC system

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hajime Sato 2 Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Masao Wada 2-29, Heian-cho, Tsurumi-ku, Yokohama-shi, Kanagawa 1 share Inside the KYOSAN MFG.

Claims (1)

[Claims] 1. A voltage output terminal of each phase of a three-phase AC system and its primary side are connected, and each of the AC voltages of each phase input from a voltage output terminal of each phase of the three-phase AC system. A three-phase transformer for converting the voltage and outputting the converted AC voltage from the secondary side thereof, respectively connected to the secondary side of the three-phase transformer, and connected to each of a plurality of sets of storage batteries; A single unit comprising a plurality of sets of single-phase direction converters for converting the converted AC voltage of each phase input from the three-phase transformer into DC voltage and supplying the DC voltage to the storage battery for charging or discharging. A charge / discharge device for a storage battery, comprising: