JP3430121B2 - Energy transfer device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy transfer device connected to a plurality of energy storage means and transferring energy between the energy storage means. The present invention relates to an energy transfer device suitable for equalizing voltages across a plurality of energy storage means. [0002] Today, the development of electric vehicles is active, and the development of batteries for driving the electric vehicles is also active. As such a battery, an electric double layer capacitor is currently considered promising. On the other hand, at this stage, it is difficult to charge the electric double layer capacitor to a high voltage. Therefore, in order to use a high-capacity battery capable of outputting a high voltage as a desirable electric vehicle battery, several to several tens of batteries are connected in series, and the voltage between terminals of each electric double layer capacitor is made equal. It is necessary to charge efficiently. For this reason, the applicant has already proposed a transfer device as a device for equalizing electric energy stored in a plurality of electric double layer capacitors (Japanese Patent Application No. 11-113235). The transfer device 3 already proposed by the applicant has
Basically, as shown in FIG. 3, for example, as shown in FIG. 3, for example, N capacitors C <b> 1 to CN (hereinafter referred to as “capacitor C” when not distinguished) serving as electric energy storage means connected in series in a battery BT. ) It is configured to allow the transfer of energy between each other. Specifically, the transfer device 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 transfer device 31 is provided with each winding W
And switches S1 to SN (hereinafter referred to as "switch S" when not distinguished) connected between the winding end side terminal and the negative side terminal of the capacitor C.
A diode D1 connected between the winding start terminal of (N + 1) and the negative terminal of the capacitor CN. In this case, each switch S is formed of, for example, an FET or a bipolar transistor, and is turned on / off in synchronization with each other by a control unit (not shown). Further, the transfer device 31 includes the connector 3 for connection,
The connection connector 3 is configured to be connectable to the connection connector 21 on the battery BT side. In this transfer device 31, the connection connector 3 is connected to the connection connector 21 on the battery BT side, and in this state, each switch S is synchronously controlled to be turned on. At this time, the capacitor C having a higher inter-terminal voltage among the capacitors C outputs a current through a current path including the plus side terminal, the winding W, the switch S, and the minus side 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 12 is excited. At the same time, the current based on each induced voltage is applied to the winding start side terminal of each winding W, the capacitor C, the switch S, and each winding W
, The capacitors C other than the capacitor C having a high inter-terminal voltage are charged. Next, charging is sequentially stopped from the capacitor C whose inter-terminal voltage has reached a voltage equal to the induced voltage. As a result, part of the energy stored in the capacitor C having the higher inter-terminal voltage is dispersedly transferred to another capacitor C. Next, when the switch S is controlled to be turned off, a current based on the excitation energy of the transformer 12 is expressed as
End terminal of winding W (N + 1), capacitor C1
To CN, a diode D1, and a winding W (N
+1) flows through the current path consisting of the winding start side terminal, whereby the excitation energy of the transformer 12
Will be relocated to As described above, by turning on / off each switch S in synchronization, a part of the energy stored in the capacitor C having a high inter-terminal voltage is dispersedly transferred to another capacitor C. As a result, a simple configuration is achieved. The voltage between terminals of each capacitor C can be equalized. [0006] However, the transfer device 31 proposed by the present applicant has the following points to be improved. That is, in the transfer device 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, due to the initial failure of the switch S, the use of the switch S for many years, or the like, a failure of the switch itself that causes the switch S to be in an open state, or a switching signal for controlling ON / OFF of the switch S is not input to the specific switch S. Circuit failure may occur. In such a case, a switching failure occurs in which only the specific switch S is not turned on. At that time, the capacitors C connected to the switches are not turned on, so that a part of the stored energy cannot be released to the other capacitors C. Is turned off, the excitation energy of the transformer 12 is forcibly accumulated. For this reason, the voltage between terminals of only the capacitor C continues to rise. Therefore, contrary to the purpose of equalizing the voltage between the terminals of each capacitor C, there is a possibility that the voltage between the terminals of the specific capacitor C may abnormally increase, and the transfer device 31 is desired to improve this point. . SUMMARY OF THE INVENTION The present invention has been made to solve such a point to be improved, and has as its main object to provide an energy transfer device capable of avoiding an abnormal increase in voltage between terminals in energy storage means. [0008] In order to achieve the above object, an energy transfer device according to claim 1 has a transformer having a plurality of windings which are magnetically coupled to each other and wound with the same number of turns. A plurality of switch means respectively connected in series to each winding and switched in synchronization with each other, and each of a series circuit comprising at least the winding and the switch means is respectively connected in parallel to each of the plurality of energy storage means. An energy transfer device configured to be capable of monitoring a voltage between both ends of each of the switch means in an ON state, and the voltage between both ends is stored in the energy storage device.
Upper limit of variation width allowed for voltage between terminals of means
Voltage monitoring means that outputs the monitoring result when the value is exceeded
And at least one of the voltages across each of the terminals exceeds the upper limit.
Is output from the voltage monitoring means.
When the switching to the switch means
And a control unit for stopping the operation.
In this case, the output of the monitoring result includes the display of the voltage value itself of the voltage between both ends of each switch means, the output of the voltage data corresponding to each voltage value, and the variation width of one of the voltages at each end.
Output of an alarm signal when the upper limit value is exceeded. Preferred embodiments of an energy transfer device according to the present invention will be described below with reference to the accompanying drawings. Note that the same components as those of the transfer device 31 are denoted by the same reference numerals, and redundant description will be omitted. First, the operating principle of the energy transfer device according to the present invention will be described with reference to FIG. In addition,
In the figure, an electric double layer type capacitor C2 connected in series in a battery BT as electric energy storage means
To C (N-1) and capacitors C2 to C (N-1)
The illustration of each component in the transfer device 1 corresponding to the above is omitted. It is also assumed that the capacitors C1 to CN are charged by a charging device (not shown). The transfer device 1 includes a transformer 2 having windings W1 to WN wound with the same number of turns. In this case, it is assumed that the transformer 2 functions as an ideal transformer having a resistance component of each winding W of 0Ω, no leakage inductance, and no excitation current. The windings W1 to WN are magnetically coupled to each other by an iron core. Further, the transfer device 1 includes switches S1 to SN, a connector 3, a control unit 4, and drive circuits A1 to AN.
(Hereinafter, referred to as “drive circuit A” when not distinguished), voltage detection circuits B1 to BN (hereinafter, referred to as “voltage detection circuit B” when not distinguished) and a determination circuit 5. The switch S corresponds to the 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 control unit 4
When a power switch (not shown) is turned on, a switching control signal SS as an oscillating signal of the oscillating circuit is output to the drive circuits A1 to AN to turn on / off the switches S1 to SN. Control off-switching. When the discrimination circuit 5 outputs the alarm signal SA, the control unit 4 switches the switching control signal S
Stop output of S. Each drive circuit A drives each switch S by outputting the switching control signal SS output from the control unit 4 in a state of being mutually insulated. Each of the voltage detection circuits B1 to BN includes a switch S
Detection signals SD1 to SD1 when the voltage between both ends exceeds a predetermined voltage.
DN (hereinafter, referred to as “detection signal SD” when not distinguished) is output to the discriminating circuit 5. The determination circuit 5
Together with the voltage detection circuits B1 to BN, a voltage monitoring means according to the present invention is constituted. When the detection signal SD is output from at least one of the voltage detection circuits B, the high level alarm signal SA is output to the control unit 4 and Output to the outside of the device. In this transfer device 1, when a power switch (not shown) is turned on, the control unit 4 outputs a switching control signal SS to each switch S via the drive circuit A, thereby synchronizing each switch S. To turn it on. At this time, the capacitor C having a higher inter-terminal voltage among the capacitors C outputs a current through a current path including the plus side terminal, the winding W, the switch S, and the minus side terminal of the capacitor C. In this case, a voltage equal to the voltage between the terminals of the capacitor C is induced at both ends of each winding W. 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 high capacitor C is charged. Then
As a result of the charging being sequentially stopped from the capacitor C whose terminal voltage has reached the voltage equal to the induced voltage, part of the energy stored in the capacitor C having the higher terminal voltage is dispersed and transferred to another capacitor C. Therefore, the voltage between the terminals of each capacitor C can be equalized with a simple configuration. On the other hand, each voltage detection circuit B monitors the voltage across each switch S in the ON state. In this case, while each switch S is in the ON state, as shown in FIG.
A voltage VW is induced in each winding W, and the voltage value of the voltage VW is substantially equal to the voltage between the terminals of the capacitor C having a high terminal voltage. At this time, the voltage between both ends of each of the switches S in the on state is almost 0V. On the other hand, when the switch SL (L is a specific number from 1 to N) is not turned on due to a malfunction or the like, the voltage across the switch SL is equal to the voltage VW induced in the winding WL, It becomes a difference voltage from the voltage between the terminals of the capacitor CL. Further, when the capacitance value of the capacitor CL is smaller than the capacitance value of the other capacitor C, the voltage between the terminals becomes the charging voltage of the other capacitor C even when the charging device is charged with the same charging current. More than rise. In addition, the stored energy is stored in another capacitor C
, The voltage between the terminals of the capacitor CL is
There is a risk of rising abnormally. Therefore, as the voltage between the terminals of the capacitor CL increases, the voltage across the switch SL also gradually increases. Therefore, the voltage detection circuit BL
Sets the upper limit value of the variation width allowable for the voltage between the terminals of each capacitor C to a predetermined voltage, and outputs a detection signal SD when the voltage across the switch SL exceeds the predetermined voltage. In this case, the upper limit value of the variation width is appropriately defined according to the type of the capacitor C, for example, 0.2 V
It is defined as a voltage value within a range of about 0.8 V. As a result, each of the voltage detection circuits B reliably detects an abnormal variation in the voltage between the terminals of each of the capacitors C caused by a malfunction of the switch S or the like. At this time, when the detection signal SD is output from at least one of the voltage detection circuits B, the discrimination circuit 5 outputs an alarm signal SA to the outside of the apparatus and also outputs it to the control unit 4. Next, when the control unit 4 detects the input of the alarm signal SA, the control unit 4 stops the output of the switching control signal SS to control each switch S to an off state. Thus, when the switch S is malfunctioning, an abnormal increase in the voltage between the terminals of the capacitor C connected to the switch S can be reliably avoided. A control unit (not shown) that has received the alarm signal SA can detect a failure of the transfer device 1. Next, the specific configuration and operation of the energy transfer device according to the present invention will be described with reference to the transfer device 11 shown in FIG. 2 as an example. The same components as those of the transfer devices 1 and 31 are denoted by the same reference numerals, and redundant description will be omitted. Further, electric double layer type capacitors C2 to C (N-1) and capacitors C2 to C2 connected in series in a battery BT as electric energy storage means.
Illustration of each component in the transfer device 11 corresponding to C (N-1) is omitted. As shown in FIG. 1, the transfer device 11 includes a transformer 12 and a drive circuit 13 for driving each switch S, instead of the corresponding structure of the transfer device 1.
Further, a drive circuit 14 for driving each of the voltage detection circuits B1 to BN in synchronization with the switching control signal SS is provided.
In this transfer device 11, a switch SM (in the present specification, the symbol M is the M-th number of the capacitors C1 to CN or the transfer device 1 corresponding to the capacitor CM)
1 means the M-th number of each component. Also,
Hereinafter, when it is not necessary to distinguish each component, the description of the last digit corresponding to the symbol M will be omitted) is configured by an n-channel FET 1M and a resistor R1M. The voltage detection circuit BM includes an n-channel type FET 2M,
It comprises an npn-type transistor 1M, resistors R2M and R3M, a photodiode PD1M, and a resistor R4M. The determination circuit 5 includes N phototransistors PT
11 to PT1N, and a phototransistor PT1M
When the photodiode PD1M emits light, it shifts from the off state to the on state and outputs a high-level alarm signal SA. The drive circuit 13 includes an FET for amplifying the switching control signal SS output from the control unit 4.
31, a resistor R51 and a transformer TR1. In this case, the transformer TR1 is connected to the FET 31
And a N number of secondary windings, which are connected to the drains of the first and second terminals to input the switching control signal SS. Each secondary winding has an N-branch in which the winding start terminal is connected to the gate of each FET 1 via the resistor R6M and the winding end terminal is connected to the source, and the switching control signal SS is insulated. To the gate of each FET1. Further, the drive circuit 14 includes a transformer TR2 and resistors R71 to R7N.
R2 has a primary winding connected to the FET 31 and N secondary windings. In this case, in each of the secondary windings, the winding start side terminal is connected to the gate of the FET 2 via the resistor R7, and the winding end side terminal is connected to the source of the FET 2 respectively. Next, the operation principle of the transfer device 11 will be described. First, a power switch (not shown) of the transfer device 11 is turned on. In this case, when the control section 4 outputs the switching control signal SS, the FET 31 amplifies the switching control signal SS. At this time, the transformer TR1
, A switching control signal SS is induced in each of the secondary windings. Then
This switching control signal SS is output to the gate of the FET 1 in each switch S, whereby
Shifts to the ON state. When each FET 1 shifts to the ON state, the capacitor C having the higher voltage across the terminals outputs a current in the same manner as the operation of the transfer device 1, and at that time, the terminal of the capacitor C A voltage VW equal to the inter-voltage is induced at both ends of each winding W, and the transformer 12 is excited. At the same time, in the same manner as the operation of the transfer device 1, part of the energy stored in the capacitor C having a high inter-terminal voltage is dispersed and transferred to another capacitor C. On the other hand, when the switching control signal SS is the FET
When amplified by 31, the current flows through the primary winding of the transformer TR2, so that a switching control signal SS is induced in each secondary winding. Next, the switching control signal SS is supplied to the gate of the FET 2 in each voltage detection circuit B via the resistor R7. Thereby, each FET 2 is controlled to the ON state. in this case,
If the drain-source voltage of FET2 is neglected, the transistor TR1 transitions from the off state to the on state when the drain-source voltage of FET1 exceeds the predetermined voltage, with about 0.6V being the predetermined voltage. That is,
When the voltage between the terminals of the capacitor CL increases due to the operation failure of the switch SL and the voltage across the switch SL exceeds a predetermined voltage, the transistor TR1L shifts to the ON state. Thereby, the photodiode PD1L connected to the collector of the transistor TR1L emits light. As a result, the corresponding phototransistor PT1L in the determination circuit 5 shifts from the off state to the on state, so that the alarm signal SA is output to the outside of the apparatus and to the control unit 4. In this case, when the control unit 4 detects the input of the alarm signal SA, it stops the output of the switching control signal SS to control each switch S to an off state. As a result, the switching control signal S is generated due to an element failure of the FET 1 in which the drain-source is open, a failure of one of the secondary windings of the transformer TR1, and the like.
An abnormal rise in the voltage between the terminals of the capacitor C due to a circuit failure or the like in which the FET 1 is not turned on because S is not supplied to the gate is avoided. On the other hand, when the voltage between both ends of each switch S does not exceed the predetermined voltage, the control unit 4 stops the output of the switching control signal SS after the predetermined time has elapsed, thereby turning each switch S off. Control. In this case,
The current based on the excitation energy of the transformer 12 is
Winding end terminal of (N + 1), capacitors C1 to CN
Circuit, diode D1, and winding W (N + 1)
Flows through the current path consisting of the winding start side terminal of
The excitation energy of the transformer 12 is dispersed and transferred to each capacitor C. As a result, each switch S is turned on /
By performing the off-switching control, part of the energy stored in the capacitor C having a high inter-terminal voltage is dispersed and transferred to another capacitor C. As described above, according to the transfer device 11,
Each voltage detection circuit B monitors the voltage between both ends of the FET 1 and makes the photodiode PD1 emit light when the voltage exceeds a predetermined voltage. At that time, the discrimination circuit 5 outputs an alarm signal SA, so that each FET 1 It is controlled to be in the off state by the control unit 4. For this reason, an abnormal rise of the voltage between terminals in the capacitor C can be avoided promptly.
At the same time, the alarm signal SA is output to the outside of the device, so that the control device outside the device can reliably detect an abnormal state of the switch S and the like and an abnormal variation in the voltage between the terminals of the capacitor C. . It should be noted that the present invention is not limited to the above-described embodiment of the present invention, and the configuration thereof can be appropriately changed. For example, in the embodiment of the present invention, an electric double layer capacitor has been described as an example of the energy storage means. However, 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. Also, 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. Also, the configuration of the voltage monitoring means is not limited to the embodiment of the present invention. For example, a Zener diode or the like is used to set the voltage across the switch S to the upper limit value while each switch S is in the ON state. It is also possible to adopt a configuration that can output an alarm signal SA when it exceeds
Various known circuits can be applied. Further, a configuration in which the voltage monitoring means monitors the voltage between both ends of the switch means periodically or only when a predetermined switch is operated may be adopted. In addition, the application range 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.
Needless to say, the present invention can be applied to various uses, for example, when the voltage between both ends of the large-capacity storage means is made uniform. As described above, according to the energy transfer device of the first aspect, the voltage between both ends of each switch means in the ON state is monitored, and the voltage between both ends is stored in the energy storage means.
The upper limit of the allowable variation width of the
A voltage monitor means for outputting a result of the monitoring when exceeded,
At least one of the voltages at both ends exceeds the upper limit of the variation width
That the monitoring result is output from the voltage monitoring means
To stop switching to the switch means
With the control unit, malfunction of the switch means
Between the terminals of each energy storage
Abnormal pressure variations can be reliably detected and this
Edge in energy storage means due to constant variation
Abnormal rise in the child voltage can be avoided quickly
You.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a transfer device 1 for explaining the operation principle of the present invention.
FIG. FIG. 2 is a circuit diagram of the transfer device 11 according to the embodiment of the present invention. FIG. 3 is a circuit diagram of a transfer device 31 already proposed by the applicant. [Description of Signs] 1,11 Transfer device 2,12 Transformer 4 Control unit 5 Discrimination circuit 12 Transformers B1 to BN Voltage detection circuit BT Battery C1 to CN Capacitor S1 to SN Switch SA Alarm signal W1 to WN Winding

Continuation of the front page (56) References JP-A-9-148901 (JP, A) US Pat. No. 5,821,729 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02J 1/00-1 / 16 H02J 7/00-7/12 H02J 7/34-7/36 H02H 7/12

Claims (1)

(57) [Claims] [Claim 1] Magnetically coupled to each other and wound with the same number of turns
A transformer having a plurality of windings, and a plurality of switch means connected in series to the respective windings and switched in synchronization with each other, each of a series circuit comprising at least the windings and the switch means An energy transfer device configured to be connected in parallel to each of the plurality of energy storage means, wherein a voltage between both ends of each of the switch means in an ON state is monitored, and the both-end voltage is set between terminals of the energy storage means.
If the voltage exceeds the upper limit of the allowable variation range
A voltage monitor means for outputting the monitoring result to come, wherein at least one of the voltage across it exceeds the upper limit value
Is output from the voltage monitoring means.
The switching to the switch means is stopped.
And a control unit for stopping the energy transfer.