JP2002142371A - Voltage equalizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily, surely, and quickly detect short-circuiting in switching means, are at a low cost. SOLUTION: A voltage equalizer 1 is provided with a transformer 2, including at least a plurality of windings W1 to WN for equalization magnetically coupled with one another and switching means S1 to SN that are series connected with the windings W1 to WN for equalization and are switched, in synchronization with the windings. In the voltage equalizer, each of series circuits comprising the windings W1 to WN for equalization and the first switch means S1 to SN is connectable to each of power storage means C1 to CN. The voltage equalizer is also provided with a voltage-detecting means B for detecting the voltage VW across any of the windings W1 to WN, wound on the transformer during switching of the switch means S1 to SN and outputs an alarm signal SA to the outside of the equipment, when the detected voltage VW across the winding is not more than prescribed voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage equalizer suitable for equalizing the storage voltage of each storage means by mutually transferring electrical energy stored in a plurality of storage means.

[0002]

2. Description of the Related Art Today, the development of electric vehicles is active, and the development of batteries for driving the electric vehicles is also active. At present, it is difficult to charge the electric double-layer capacitor to a high voltage as an electric double-layer capacitor as a battery of this kind. Therefore, in order to use a high-voltage and large-capacity type as a desirable battery for electric vehicles, several batteries are required.
It is necessary to connect several tens of capacitors in series and charge them efficiently so that the voltage between terminals of each electric double layer capacitor becomes equal. For this reason, a voltage equalizer has already been developed as a device for equalizing electric energy stored in a plurality of electric double layer capacitors.

The already developed voltage equalizer 3
Basically, as shown in FIG. 5, for example, N capacitors C1 to CN (hereinafter, referred to as "capacitor C" when not distinguished) as electric energy storage means connected in series in a battery BT, as shown in FIG. ) Can be made uniform. Specifically, the voltage equalizer 31 includes windings W1 to WN wound with the same number of turns.
(Hereinafter referred to as "winding W" when not distinguished)
The winding W (N +) wound with N times the number of turns of the winding W
1). in this case,
Each of the windings W1 to W (N + 1) is magnetically coupled to each other by an iron core. Further, the voltage equalizer 31 includes switches S1 to SN (hereinafter, referred to as “switch S” when not distinguished) connected between the winding end side terminal of each winding W and the negative side terminal of each capacitor C, respectively.
Winding start terminal of winding W (N + 1) and capacitor CN
And a diode D11 connected between the negative terminals of the first and second terminals. In this case, each switch S is, for example, FE
T and bipolar transistors, which are turned on / off in synchronization with each other by a control unit (not shown).

In this voltage equalizer 31, first, each switch S is synchronously controlled to be turned on. In this case,
The capacitor C having the highest terminal voltage among the capacitors C outputs a current through a current path including the plus terminal, the winding W, the switch S, and the minus terminal of the capacitor C. In this case, a voltage substantially equal to the voltage between the terminals of the capacitor C is induced at both ends of each winding W, and the transformer 32 is excited. At the same time, the current based on the respective induced voltages continues to flow through the current path including the winding start terminal of each winding W, the capacitor C, the switch S, and the winding end terminal of each winding W, so that the terminal voltage is reduced. Each of the capacitors C other than the highest capacitor C is charged. In this case, charging of the capacitor C whose terminal voltage has reached a voltage equal to the induced voltage is automatically stopped. As a result, the capacitor C having the highest terminal voltage
A part of the stored energy is dispersedly transferred to another capacitor C.

Next, when the switch S is turned off, a current based on the excitation energy of the transformer 32 is generated.
End terminal of winding W (N + 1), capacitor C1
To CN, a diode D11, and a winding W
The current flows through the current path including the (N + 1) winding start side terminal, whereby the excitation energy of the transformer 32 is dispersed and transferred to each capacitor C. As described above, by turning on / off each switch S synchronously, part of the energy stored in the capacitor C having the highest inter-terminal voltage is dispersedly transferred to another capacitor C, and as a result, the voltage between the terminals of each capacitor C is reduced. The voltage can be made uniform.

[0006]

However, the voltage equalizer 31 has the following problems. That is, in the voltage equalizer 31, a large number of switches S provided corresponding to a large number of capacitors C are turned on / off synchronously. On the other hand, the switch S
May cause a failure of the switch itself, which causes a short circuit. In such a case, a switching failure occurs in which only the specific switch S is always on. At that time, the winding W connected to the switch short-circuits the capacitor C connected via the switch, so that an overcurrent flows through the winding W. Therefore, the winding W
Not only causes magnetic saturation of the wound transformer 32 so that the transformer 32 does not function as a transformer, but also in the worst case, there is a problem that the winding W may be burned.

In this case, a configuration is adopted in which a current transformer is connected in series between the winding start side terminal of each winding W and the positive terminal of each capacitor C, and the current value flowing through each winding W is always detected. Is also conceivable. When this configuration is employed, when a current exceeding a predetermined value flows through at least one winding W, it is possible to determine that a short circuit has occurred in the switch S connected to the winding W. . However, the method of providing a current detecting means such as a current transformer for each winding W has a problem that the number of components is greatly increased, and accordingly, the product cost is increased and the voltage equalizer is enlarged.

SUMMARY OF THE INVENTION The present invention has been made to solve such a point to be improved, and it is an object of the present invention to provide a voltage equalizer which can detect a short-circuit abnormality of a switch means simply, inexpensively, and reliably and quickly. The main purpose is.

[0009]

According to a first aspect of the present invention, there is provided a voltage equalizer, comprising: a transformer having at least a plurality of equalizing windings magnetically coupled to each other; and a series connected to each of the equalizing windings. A plurality of first switch means connected and controlled to be switched in synchronization with each other, each of a series circuit including the equalizing winding and the first switch means being connected to each of the plurality of power storage means. A voltage equalizer configured to be connectable in parallel, comprising voltage detecting means for detecting a voltage across one of the windings wound around the transformer at the time of switching of the first switch means,
When the voltage across the terminals detected by the voltage detecting means is equal to or lower than a predetermined voltage, an alarm signal is output to the outside of the device.

A voltage equalizer according to a second aspect of the present invention comprises:
2. The voltage equalizer according to claim 1, further comprising a plurality of second switch means respectively connected between each of said series circuits and each of said plurality of power storage means, wherein said two ends detected by said voltage detection means. When the voltage is equal to or lower than a predetermined voltage, the second switch means disconnects the connection between each of the series circuits and each of the plurality of power storage means.

A voltage equalizer according to a third aspect of the present invention comprises:
A transformer having at least a plurality of equalizing windings magnetically coupled to each other, and a plurality of first switch means connected in series to each of the equalizing windings and switching-controlled in synchronization with each other; A voltage equalizer configured so that each of a series circuit including an equalizing winding and said first switch means can be connected in parallel to each of a plurality of power storage means, wherein said transformer is connected when said first switch means is switched. Voltage detecting means for detecting a voltage between both ends of any one of the windings, and a plurality of second switch means respectively connected between each of the series circuits and each of the plurality of power storage means. When the voltage between both ends detected by the voltage detecting means is equal to or less than a predetermined voltage, the second switch means Characterized in that to release the connection between each of each said plurality of storage means of said series circuit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a voltage equalizer according to the present invention will be described below with reference to the accompanying drawings. The same components as those of the voltage equalizer 31 are denoted by the same reference numerals, and redundant description will be omitted. Since the voltage equalizing operation itself is performed in the same manner, description thereof will be omitted.

First, the operation principle of the voltage equalizer 1 according to the present invention will be described with reference to FIG. In the figure, a battery B as an electric energy storage means is shown.
Electric double layer type capacitors C2 connected in series in T
Illustration of each component in the voltage equalizer 1 corresponding to C (N-1) and the capacitors C2 to C (N-1) is omitted. It is also assumed that the capacitors C1 to CN have already been charged.

The voltage equalizer 1 includes a transformer 2 in which windings (equalizing windings) W1 to WN having the same number of turns and a resetting winding (other windings) WR are wound. In this case, the windings W1 to WN, WR are magnetically coupled to each other by an iron core. Further, the voltage equalizer 1 includes switches S1 to SN, switches F1 to FN (hereinafter, referred to as “switch F” when not distinguished), the control unit 4, and drive circuits A1 to AN (hereinafter, “drive circuit A” when not distinguished). ), And a voltage detection circuit B and a determination circuit 5.

The switch S corresponds to the first switch means in the present invention, and is connected between the winding end terminal of each winding W and the negative terminal of each capacitor C. The switch F corresponds to a second switch in the present invention,
As an example, it is connected between the winding start side terminal of each winding W and the plus side terminal of each capacitor C, and has a function of interrupting a current path. In this case, the switch F can be provided at an arbitrary position in the current path including the plus terminal of each capacitor C, the winding start terminal of each winding W, the switch S, and the minus terminal of each capacitor C. Each of the switches S and F is usually configured by a semiconductor switch element such as a transistor or an FET. Further, the switch F
In the normal state, the on state is maintained. Note that the switch F
Is operated when a short circuit abnormality occurs in the switch S, unlike the switch S which constantly repeats on / off switching. May be adopted.

The control unit 4 has a built-in oscillation circuit, and outputs a switching control signal SS as an oscillation signal of the oscillation circuit to the drive circuits A1 to AN when a power switch (not shown) is turned on, Each switch S1 to S
N controls on / off switching. Further, when the discrimination circuit 5 outputs the alarm signal SA, the control unit 4 stops the output of the switching control signal SS to control each switch S to the off state, and also controls the cutoff control signal SE.
To control each switch F to an off state.

Each drive circuit A drives each switch S by outputting the switching control signal SS output from the control unit 4 in a state in which they are insulated from each other. The voltage detection circuit B constitutes a voltage detection means in the present invention, and is connected to both terminals of the winding W1, for example, and rectifies the voltage VW between the terminals of the winding W1 to rectify the voltage detection signal SV.
Is generated and output to the determination circuit 5.

When the switching signal SS is output from the control unit 4 and the voltage value of the voltage detection signal SV detected by the voltage detection circuit B is equal to or less than a predetermined voltage, the determination circuit 5 It is determined that a short circuit abnormality has occurred in the switch S, and in that case, an alarm signal SA is output to the control unit 4 and the outside of the device.

In the voltage equalizer 1, when all the switches S are operating normally, when the switching control signal SS shown in FIG. 2A is at a high level (when the switch S is on), As shown in FIG. 3B, a terminal voltage VW substantially equal to the terminal voltage of the capacitor C having the highest terminal voltage is generated between the terminals of the winding W1. Conversely, when the switching control signal SS is at a low level (when the switch S is off), the energy stored in the transformer 2 is transferred to the winding WR and the diode D1.
Is discharged to each capacitor C through Therefore, at this time, a negative flyback voltage is generated in each winding W as a terminal-to-terminal voltage VW, as shown in FIG. In this case, the voltage detection circuit B rectifies the terminal voltage VW generated in the winding W1 to generate a positive voltage detection signal SV.

On the other hand, when a short-circuit abnormality occurs in any one of the switches S, regardless of whether each switch S is on or off, the capacitor C connected to the switch S, the winding W, and the switch S The current continues to flow through the current path, and the transformer 2 is magnetically saturated. At this time, the magnetic flux density hardly changes. Therefore, since the transformer 2 does not function as a transformer, almost no induced voltage is generated in each winding W, and the winding resistance (DC resistance) of the winding W is slightly increased.
Is multiplied by the current value. In particular,
As shown by the solid line in FIG. 2 (c), a positive terminal voltage VW of approximately 0 V is generated in each winding W. Therefore,
The discrimination circuit 5 detects the winding W1 during normal switching.
Between terminals Vw (shown by a broken line in FIG. 3 (c))
When the switching control signal SS is being output, a voltage lower than the absolute value (positive voltage) (for example, half the voltage) is set as a reference voltage (predetermined voltage in the present invention) VREF. When VW is lower than VREF, it is determined that a short circuit has occurred, and an alarm signal SA is output. In this case, the voltage VREF may be set to a voltage value that can detect that the transformer 2 is not functioning properly. The voltage value VREF is の of the terminal voltage VW induced in the winding W1 in a normal state. However, any voltage value such as 1/3, 1/4,... May be used. Further, at the time of magnetic saturation of the transformer 2, the voltages between the terminals generated in all the windings W decrease together, so that the voltage detection circuit B
To any one of the windings W1 to WN, WR,
The terminal voltage VW generated in the winding W can also be detected.

On the other hand, when detecting the input of the alarm signal SA, the control unit 4 stops the output of the switching control signal SS and controls each switch S to an off state, and outputs a cutoff control signal SE to output each of the switches S. The switch F is turned off. As a result, the connection between each of the capacitors C and each of the windings W is released, and an overcurrent can be reliably and promptly prevented from flowing through each of the windings W. Further, in the control device (not shown), the failure of the voltage equalizer 1 can be reliably detected by inputting the alarm signal SA.

It should be noted that the present invention is not limited to the above-described embodiments of the present invention, but can be appropriately modified. For example, FIG.
As shown in the voltage equalizer 11 shown in FIG.
Instead of N and WR, the voltage VS of the auxiliary winding WS wound around the transformer 2A may be detected.

Further, for example, the present invention can be applied to the voltage equalizer 21 shown in FIG. In the figure, the same components as those of the voltage equalizers 1 and 11 are denoted by the same reference numerals, and redundant description will be omitted. The voltage equalizer 21 also functions as a charging device, and turns on / off in reverse synchronization with the on / off of the switches S1 to SN and the transformer 2B in which the winding WP is further wound in addition to the N windings W. It comprises a switch SP controlled and connected in series with the winding WP, and a battery B1 connected to a series circuit of the winding WP and the switch SP. In this voltage equalizer 21, first, the switch SP is turned on and the switches S1 to SN are turned off. In this case,
A current is supplied from the battery B1 to the winding WP, and energy is stored in the transformer 2B. Then switch S
P is turned off, and switches S1 to SN are turned on. At this time, the energy stored in the transformer 2B is released from the windings W1 to WN to the capacitors C1 to CN. In this case, more current is supplied to the capacitor C having a lower terminal voltage. Therefore, the voltage between terminals of each capacitor can be equalized while each capacitor C is charged by the battery B1. Also in this voltage equalizer 21, the voltage detection circuit B in the voltage equalizer 1 is connected to any one of the windings W1 to WN and WP, and the voltage detection signal SV is determined by the determination circuit 5
, The discrimination circuit 5 allows the switches S1 to S1
It is possible to detect a short circuit abnormality of SN and SP.

Also, in the embodiment of the present invention, an electric double layer capacitor has been described as an example of the energy storage means, but the present invention is not limited to this, and various types of capacitors and secondary batteries are included. Further, the present invention is not limited to the case where each energy storage unit is connected in series, and is applicable to a case where each energy storage unit is separately and independently in an insulated state. Further, the present invention can be applied to the case where the rated charging voltages of the energy storage units are different. In such a case, the turns ratio of each winding W may be defined so as to be proportional to the rated charging voltage of each energy storage means. Further, in the embodiment of the present invention, the configuration in which the discrimination circuit 5 outputs the alarm signal SA to the outside of the apparatus has been described as an example, but the terminal voltage VW detected by the voltage detection circuit B is output to the external apparatus. Then, the switch S is supplied to an external device based on the terminal voltage VW.
May be adopted to determine the short-circuit of.

In addition, the scope of application of the present invention is not limited to the use of equalizing the voltage between terminals of a capacitor as each cell of an automobile battery. For example, an electric storage system in which large-capacity electric storage means are connected in series In this case, it is needless to say that the present invention can be applied to various uses such as a case where the voltage between both ends of the large-capacity power storage means is made uniform.

[0026]

As described above, according to the voltage equalizer of the first aspect, the voltage detecting means detects the voltage across one of the windings wound around the transformer at the time of switching of the first switch means. By doing so, it is possible to reliably and quickly detect a short-circuit abnormality of all switch means, and to output an alarm signal to the outside of the device when the voltage across the terminals detected by the voltage detection means is equal to or lower than a predetermined voltage. The failure of the voltage equalizer can be reliably notified to, for example, a control device or an operator outside the device. Further, as compared with a system in which a current transformer or the like is connected in series to all of the windings, the number of components and the product cost can be reduced, and the size of the voltage equalizer can be reduced.

According to the voltage equalizer of the second and third aspects, the voltage detecting means detects the voltage across one of the windings wound around the transformer at the time of switching of the first switch means. In addition, the short-circuit abnormality of all the switch means can be detected reliably and quickly, and the short-circuit abnormality can be detected by controlling the second switch means when the voltage between both ends detected by the voltage detection means is equal to or lower than a predetermined voltage. At this time, the connection between each of the series circuits and each of the plurality of power storage means can be quickly released. Also,
According to the voltage equalizer of the third aspect, it is possible to reduce the number of parts and the product cost as compared with a method in which a current transformer or the like is connected in series to all of the windings, and to reduce the size of the voltage equalizer. Can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of a voltage equalizer 1 according to the present invention.

2A and 2B are signal waveform diagrams for explaining the operation of the voltage equalizer 1, wherein FIG. 2A is a voltage waveform diagram of a switching control signal SS, FIG. 2B is a voltage waveform diagram of a terminal voltage VW,
(C) is a voltage waveform diagram of the inter-terminal voltage VW when one of the switches S has a short circuit abnormality, and a voltage waveform diagram of the inter-terminal voltage VW when each switch S is operating normally.

FIG. 3 is a block diagram of a voltage equalizer 11 according to the present invention.

FIG. 4 is a circuit diagram of a voltage equalizer 21 according to the present invention.

FIG. 5 is a block diagram of a voltage equalizer 31 that has already been developed.

[Explanation of symbols]

 1, 11, 21 Voltage equalizer 2, 2A, 2B Transformer 4 Control unit B Voltage detection circuit BT Battery C1 to CN Capacitors S1 to SN, SP, F1 to FN Switch SA Alarm signal SE Cutoff control signal SV Voltage detection signal VW Between terminals Voltage W1-WN, WP, WR, WS winding

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroshi Nishizawa 1163 Shimoseikane, Inari-cho, Nagano City, Nagano Prefecture Inside Nagano Japan Radio Co., Ltd. (72) Inventor Fujio Matsui 1-7-2 Nishishinjuku, Shinjuku-ku, Tokyo Fuji Heavy Industries F term in reference (reference) 5G003 BA03 CA11 CC02 DA07 DA12 EA08 GB03 5G065 DA04 GA09 HA16 LA01 MA10 NA01 NA09

Claims (3)

[Claims] 1. A transformer having at least a plurality of equalizing windings magnetically coupled to each other, and a plurality of first switch means connected in series to each of the equalizing windings and switching-controlled in synchronization with each other. A voltage equalizer configured so that each of the series circuits including the equalizing winding and the first switch means can be connected in parallel to each of a plurality of power storage means, wherein the first switch means Voltage switching means for detecting the voltage across one of the windings wound around the transformer at the time of switching, when the voltage across the voltage detected by the voltage detection means is less than a predetermined voltage, an alarm signal A voltage equalizer characterized by outputting to the outside of the device. A plurality of second switch means respectively connected between each of the series circuits and each of the plurality of power storage means, wherein the both-ends voltage detected by the voltage detection means is a predetermined voltage. 2. The voltage equalizer according to claim 1, wherein said second switch means disconnects each of said series circuits from each of said plurality of power storage means at the following times. 3. A transformer having at least a plurality of equalizing windings magnetically coupled to each other, and a plurality of first switch means connected in series to each of the equalizing windings and switching-controlled in synchronization with each other. A voltage equalizer configured so that each of the series circuits including the equalizing winding and the first switch means can be connected in parallel to each of a plurality of power storage means, wherein the first switch means Voltage switching means for detecting the voltage across one of the windings wound around the transformer at the time of switching, and a plurality of voltage detection means connected between each of the series circuit and each of the plurality of power storage means. Second
Switch means, and when the voltage between both ends detected by the voltage detection means is equal to or less than a predetermined voltage, the second switch means is connected to each of the series circuit and each of the plurality of power storage means. A voltage equalizer for disconnecting a connection.