JP2003189495A - Charge/discharge controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charge/discharge controller having a simple arrangement at a low cost. <P>SOLUTION: A plurality of unit capacitors are connected in series as cells C1-C5 to constitute a power supply pack. Bi-directional switches S1-S23 are arranged between respective cells including the outer terminals of the cells C1 and C5. Each bi-directional switch is connected, at one end thereof, with the outer terminals of the cells C1 and C5 and the connection end between respective cells and, at the other end thereof, with connection terminals C and D alternately. Four bi-directional switches S1-S2' are connected, in cross, between the connection terminals C and D and the opposite ends E and F of regulation cells Cx. Under control of a first switch control circuit 10 and a second switch control circuit 12A, the regulation cells Cx are connected sequentially with respective cells of the power supply pack. Voltages of respective cells are made uniform through charge/discharge between the regulation cells Cx and respective cells thus preventing over discharge and overcharge due to variation of cell capacity. Since the charge/discharge controller is constituted of bi-directional switches and a simple control circuit, the cost can be reduced. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention equalizes the voltage of each unit battery and unit capacitor in charging / discharging of a group power source composed of a plurality of unit batteries or unit capacitors connected in series as cells, and causes a variation in capacity. The present invention relates to a charge / discharge control device that prevents overcharge and overdischarge.

[0002]

2. Description of the Related Art In an assembled battery in which a plurality of unit batteries are connected in series as an assembled power source to obtain a desired voltage and capacity,
Since the capacity of each unit battery varies depending on the state of manufacture or the state of subsequent use, the unit battery having a small capacity progresses rapidly in charging and discharging, and is likely to be overcharged or overdischarged.

In order to adjust the progress of this charging / discharging, for example, in the device disclosed in Japanese Patent Laid-Open No. 11-355966, a capacitor that can be connected in parallel with each unit battery is provided for the assembled battery, and when charging, the capacitor is overcharged. A capacitor is connected in parallel to two adjacent unit batteries including a unit battery that is about to be charged, the capacitor is charged, and then the capacitor is connected in parallel to the unit battery with the lowest charge level for discharging. By repeating this, the charging progress of each unit battery is equalized.

At the time of discharging, when a unit battery which is about to be over-discharged is detected, a capacitor is connected in parallel to two adjacent unit batteries including the unit battery having the highest charge level, and the capacitor is charged. After that, the capacitor is connected in parallel with the unit cell which is about to be over-discharged and discharged. By repeating this, the discharge progress of each unit cell is equalized. Since the charge and discharge are adjusted using the capacitor in this way, the charging current at the time of charging can be effectively used, and the capacity of each unit battery can be used up. In addition, the capacity of the capacitor is also used. .

[0005]

However, in order to perform the above-mentioned control, for example, when charging, the unit battery with the most advanced charging and the unit battery with the lowest charging level are detected from among the unit batteries. Therefore, it is necessary to connect the voltage detection circuit that detects the voltage of each unit battery, the circuit that selects the unit battery with the highest voltage and the unit battery with the lowest voltage, and the connection between the unit battery and the capacitor according to the selection result. Since a control circuit for controlling the switching switch means is required, there is a problem that the configuration is complicated and the cost becomes high. The present invention, in view of the above problems,
Aiming to provide a low-cost charge / discharge control device by using a control circuit that can be simply configured by eliminating or reducing the number of voltage detection circuits in charging / discharging a plurality of unit batteries or unit capacitors connected in series. There is.

[0006]

For this reason, the invention according to claim 1 is a charge / discharge control device for a combined power source, which is configured by connecting a plurality of batteries or capacitors in series as cells. The adjustment cell that is configured to be chargeable / dischargeable to / from each cell of the assembled power supply, the connecting means for individually connecting the adjustment cell to each cell of the assembled power supply, and the adjustment cell in order It has connection control means for controlling the connection means so as to connect to each cell of the power supply.

According to a second aspect of the present invention, there is provided current detection means for detecting a charging / discharging current flowing between the adjustment cell and the cell of the assembled power supply connected to the adjustment cell, and the connection control means is provided. Controls the connection timing of the connecting means based on the charge / discharge current.

According to a third aspect of the present invention, the connecting means comprises:
A plurality of bidirectional switches each having one end connected to both ends of the assembled power source and a connection end between cells, and the other end of each bidirectional switch is alternately connected to two connection terminals from one end side of the assembled power source. By connecting and closing two adjacent bidirectional switches, the cells connected to the connection terminals can be selected from the assembled power supply, and a polarity is provided between the two connection terminals and both ends of the adjustment cell. It is assumed that a switch for matching is connected.

According to a fourth aspect of the present invention, the connecting means comprises:
A plurality of bidirectional switches each having one end connected to both ends of the assembled power source and a connection end between cells, and the other end of each bidirectional switch is alternately connected to two connection terminals from one end side of the assembled power source. By connecting and closing two adjacent bidirectional switches, it is possible to select the cell connected to the connection terminal from the assembled power supply, and charge between the two connection terminals and both ends of the adjustment cell. A control circuit and a discharge control circuit are provided, and the charge control circuit includes a switch for controlling a charging current, a diode array for matching the polarities of the adjustment cell and the selected cell, and the discharge control circuit. Is composed of a switch for controlling a discharge current, a diode array for matching the polarities of the adjusting cell and the selected cell.

[0010]

According to the first aspect of the present invention, since the adjustment cells are sequentially connected to the cells of the assembled power supply, for example, the adjustment cells are connected to the connected cells when the voltage is higher than the connected cells. It discharges it. As a result, the voltage of the connected cell rises and the voltage of one adjustment cell falls. Further, when the voltage is lower than the voltage of the connected cell, the adjustment cell is charged from the connected cell, so that the voltage of the adjustment cell increases and the voltage of the connected cell decreases.

Therefore, the voltage of each cell of the assembled power supply can be made uniform by connecting the adjustment cells to each cell of the assembled power supply in order. Each cell can be charged and discharged according to the capacity according to the charge and discharge of the assembled power source, and it is possible to prevent overcharging and overdischarging due to capacity variation. Since the adjusting cells are sequentially connected to the cells of the assembled power supply, the connection means and the connection control means are used, so that the voltage detection circuit for detecting the cell voltage of the assembled power supply can be omitted, and also as the connection control means, Since a timer counter circuit or the like can be used, the effect of reducing the cost can be obtained.

According to the second aspect of the present invention, the connection control means controls the connection timing of the connection means based on the charging / discharging current generated between the adjustment cell and the connected cell. When the current value becomes zero or a current value that does not cause a large surge voltage, the cells connected to the adjustment cell can be switched. For example, it is not necessary to take a costly surge countermeasure for increasing the pressure resistance of the connecting means, and the cost can be reduced.

According to the third aspect of the present invention, one end of the bidirectional switch is connected to both ends of the assembled power source and the connection ends between the cells, and the other end of the bidirectional switch is alternately arranged from one end side of the assembled power source. Since the cells are connected to one connection terminal, the cells can be sequentially selected from the assembled power source and connected to the connection terminal by alternately switching the bidirectional switches connected to the two connection terminals one by one. By connecting two bidirectional switches to both ends of each cell and switching the two bidirectional switches at the same time as in the conventional method, the number of bidirectional switches to be used is reduced to about half compared to the method of selecting cells, and the cost is reduced. Can be lowered. Regarding the polarity of the adjustment cell and the selected cell, a switch for matching the polarity is connected between the connection terminal and the adjustment cell, so connect the adjustment cell and the selected cell with the same polarity. You can

According to a fourth aspect of the invention, similarly to the third aspect, one end of the bidirectional switch is connected to both ends of the assembled power source and the connection ends of the cells, and the other end of the bidirectional switch is connected to the assembled power source. Since it is connected to two connection terminals alternately from one end side, 2
By alternately switching the bidirectional switches connected to one connection terminal one by one, cells can be sequentially selected from the assembled power supply and connected to the connection terminal. The number of bidirectional switches used can be reduced and the cost can be reduced. Since the charge control circuit and the discharge control circuit are separately provided between the connection terminal and the adjustment cell, the switch for controlling the charge current or the discharge current may be a unidirectional switch, or the selected cell A diode array can be used to match the polarities of the adjusting cell and the adjusting cell, and the cost can be reduced.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described with reference to examples. FIG. 1 is a diagram showing an overall configuration of a motor drive system to which the embodiment is applied. This motor drive system includes a power supply unit 1, an inverter unit 2 and an AC three-phase motor 3.

The power supply unit 1 includes a battery Ba and a capacitor C.
a, each having a switch Sw1 and a switch Sw
2 and the switch Sw3, power can be supplied independently or in a state of being connected in parallel or in series. The electric power is supplied to the inverter unit 2 to drive the AC three-phase motor 3. The inverter unit 2 is provided with a smoothing capacitor Cb for stabilizing the voltage and switching elements Q3 to Q8 for switching DC to AC.

The AC three-phase motor 3 is capable of regenerative operation. During the regenerative operation, the regenerated electric power is sent to the power source section 1 via the inverter section 2 and used for charging the battery Ba and the capacitor Ca. Switches Sw1, Sw2, S
w3 is controlled by a control circuit (not shown) according to the charging / discharging state of the battery Ba and the capacitor Ca and the driving state of the AC three-phase motor 3.

The capacitor Ca uses a plurality of unit capacitors and is used by connecting them in series as cells in order to secure the breakdown voltage and the capacitance. Also, for each cell,
In order to prevent overcharge or overdischarge due to variation in capacity, the charge / discharge amount of each cell is adjusted to perform charge / discharge according to the capacity of the cell.

FIG. 2 is a diagram showing the internal structure of the capacitor Ca. Cell C connected in series using unit capacitors
(C1 to C5) form a combined power supply, and the outer terminals of the cells C1 and C5 are connected as output terminals to the A and B ends in the power supply unit 1. The capacitor Ca is provided with an adjustment cell Cx that exchanges electric power with each cell in the assembled power supply. The adjustment cell Cx is the same capacitor as the cells C1 to C5 of the assembled power supply.

In order to select a cell to be connected to the adjusting cell Cx from the assembled power source, cells C1 and C to be connected to the terminals A and B are selected.
Six bidirectional switches are arranged between each cell, including the outer terminal of No. 5, and one end of each bidirectional switch has cells C1 and C5.
Is connected to the outer terminal and the connection end between the cells, and the other end is alternately connected to the connection terminals C and D.

That is, the bidirectional switches S11, S21, S12, S22, and S22 are arranged in order from the outer terminal of the cell C1.
One end of S13 and S23 is connected to the connection end between each cell and the outer terminal of the cell C5, and the other end of each of the bidirectional switches S11, S12 and S13 is connected to the connection terminal C. The other ends of the direction switches S21, S22, and S23 are connected to the connection terminal D. Accordingly, by alternately switching the bidirectional switches connected to the two connection terminals one by one, cells can be sequentially selected from the assembled power supply and connected to the connection terminals C and D. The opening / closing of each bidirectional switch is controlled by a first switch control circuit (first SW control circuit) 10.
Each of the bidirectional switches S11 to S23 constitutes a connecting means.

Between the connection terminals C and D and the adjustment cell Cx, the unidirectional switches Sa and Sa 'for supplying a charging current to the adjustment cell Cx and the polarity of the adjustment cell Cx and the selected cell C are set. The diode array D12 for matching is connected, and the unidirectional switches Sb and Sb ′ for flowing a discharge current from the adjusting cell and the diode array D34 are connected. Unidirectional switches Sb, Sb '
And diode array D34 and unidirectional switch S
The polarities of a, Sa 'and the diode array D12 are opposite.

The diode arrays D12 and D34 include the adjustment cell Cx and the selected cell C, and the adjustment cells E and
When the F terminal and the connection terminals C and D have the same polarity, the diode D
1, D1 'or diodes D3, D3' are turned on.
When the polarities are inverted, the diodes D2, D2 'or D4, D4' are turned on to match the polarities. Further, when one set of diodes is turned on, the other diodes are not turned on because the cathode potential is high. Therefore, the circuit does not short.

The unidirectional switches Sa and Sa 'are control switches for charging the adjustment cell Cx from the cell C selected by the assembled power source, and constitute a charge control circuit together with the diode array D12. Unidirectional switches Sb, Sb '
Is a control switch for the adjustment switch Cx to discharge the selected cell C, and constitutes a discharge control circuit together with the diode array D34.

A voltage detector 13 is provided at both ends of the adjustment cell Cx.
The voltage detector 14 is connected to the output terminal of the diode array D12. The voltage detector 13 detects the voltage of the adjustment cell Cx, and the voltage detector 14 detects the voltage of the selected cell. Those detected values are unidirectional switches Sa, S
It is output to the second switch control circuit (second SW control circuit) 12 for controlling a ′, Sb, and Sb ′. First
Switch control circuit 10 and second switch control circuit 12
A timer counter 11 is connected to the.

FIG. 3 is a flow chart showing the control flow of the above configuration. First, in step 100, the timer counter 11 is initialized to count from a set value. The count value is transmitted to the first switch control circuit 10 and the second switch control circuit 12. In step 110, the first switch control circuit 10
According to the count value, the bidirectional switches S11 to S2
Control cell 3 to select cell C. Initially, the bidirectional switches S11 and S21 are turned on to select the cell C1.

In step 120, the second switch control circuit 12 inputs the detection values of the voltage detectors 13 and 14 and detects the voltages of the adjusting cell Cx and the cell C. Cell C
When 1 is selected, the voltage Vx of the adjustment cell Cx is compared with the voltage Vc of the selected cell C1, and the voltage Vx is V
If c or more, in step 130, the second switch control circuit 12 turns off the unidirectional switches Sa and Sa ′ and turns on the unidirectional switches Sb and Sb ′. At this time, since the adjustment cell Cx and the selected cell C1 have the same polarity, the diodes D3 and D3 ′ are turned on. As a result, the adjustment cell Cx discharges the cell C1. When the voltage Vx of the adjustment cell Cx and the voltage Vc of the selected cell are the same, the cell voltage Vc is detected including the voltage drop in the diode array. Therefore, the actual voltage is the adjustment cell Cx. Since the voltage is Vx or higher, the diode array D12 does not turn on.

On the other hand, when the voltage Vx of the adjustment cell Cx is smaller than the voltage Vc of the cell C1 in the comparison of step 120, the second switch control circuit 12 turns on the unidirectional switches Sa and Sa 'in step 140. While turning on, the unidirectional switches Sb and Sb ′ are turned off. Also at this time, since the adjustment cell Cx and the cell C1 have the same polarity,
The diodes D1 and D1 'are turned on. As a result, the adjustment cell Cx is charged from the cell C1. As described above, the adjustment cell Cx and the cell C2 have the same voltage due to mutual charging and discharging.

Next, in step 150, the timer counter 11 counts up and the process returns to step 110. Since the quint value has increased, in step 110, the first switch control circuit 10 turns on the bidirectional switches S12 and S21 to select the next cell C2. At this time, the polarity of the cell C2 connected to the connection terminals C and D is opposite to that of the cell C1.

Thereafter, as in the above, in step 120, the second switch control circuit 12 compares the voltage Vx of the adjusting cell Cx with the voltage Vc of the cell C2 and detects the magnitude relationship. When the voltage Vx of the adjustment cell Cx is equal to or higher than the voltage Vc of the selected cell C2, the second switch control circuit 12 turns off the unidirectional switches Sa and Sa ′ and also the unidirectional switches Sb and Sb in step 130. 'Turn on. At this time, the adjustment cell Cx and the selected cell C
Since the polarity of 2 is opposite, the diodes D4 and D4 'are turned on, and the adjustment cell Cx and the cell C2 have the same polarity, and then the adjustment cell discharges.

On the other hand, the voltage Vx of the adjusting cell Cx is equal to that of the cell C.
If it is smaller than the voltage Vc of 2, the second switch control circuit 12 determines in step 140 that the unidirectional switches Sa, S.
While turning on a ', unidirectional switches Sb, Sb'
To turn off. Also at this time, the adjustment cell Cx and the cell C2
Since the polarity of is the opposite, the diodes D2 and D2 'are turned on,
Similarly to the above, the polarities of the adjustment cell Cx and the cell C2 are matched, and the adjustment cell is charged from the cell C2.

Then, in step 150, when the timer counter 11 counts up, the next cell is selected again, the voltage is compared with that of the adjustment cell, and the charging / discharging is performed. As described above, each time the timer counter 11 counts up, a new cell is selected and charging / discharging is performed between the cell and the adjustment cell.

FIG. 4 is a diagram showing changes in the voltage of each cell due to the connection with the adjustment cell. Here, the adjustment cell C
x has the same capacity as the cells C1 to C5 of the assembled power supply. This is merely for convenience of display, and the capacity of the adjustment cell need not be the same as that of the assembled power supply cell.
When t = 0, the voltage of the cell C1 is V5, the voltage of the cell C2 is V4, the voltage of the cell C3 is V3, the voltage of the cell C4 is V2, the voltage of the cell C5 is V1, and the adjustment cell Cx. Is at V3. And V5>V4>V3> V2
> V1.

When t = 0.5, the timer counter 11 causes the first switch control circuit 10 to turn on the bidirectional switches S11 and S21 to select the cell C1. Based on the voltage information from the voltage detectors 13 and 14, the adjustment cell Cx
Is determined to be smaller, the second switch control circuit 12 turns on the unidirectional switches Sa and Sa ′. Since the adjustment cell Cx and the selected cell C1 have the same polarity, the diodes D1 and D1 ′ are turned on,
The cell C1 discharges with respect to the adjustment cell Cx, and each voltage becomes V4 which is the average value.

When t = 0.6, the timer counter 11 counts up, so that the first switch control circuit 10 turns on the bidirectional switches 12 and 21,
Select cell C2. Since the adjustment cell Cx and the cell C2 have the same voltage V4, the second switch control circuit 12 turns on the unidirectional switches Sb and Sb ′. Here, since there is no potential difference, the diode array D12 does not turn on, and the voltage V4 of the adjustment cell Cx and the cell C2 is maintained.

When t = 0.7, the count of the timer counter 11 is increased and the first switch control circuit 10
Turns on the bidirectional switches S12 and S22 to activate the cell C
Select 3. From the cell C3 to the voltage V4 of the adjustment cell Cx
Is larger, the second switch control circuit 12 turns on the unidirectional switches Sb and Sb ′. Adjustment cell C
Since x and cell C3 have the same polarity, diodes D3, D
By turning on 3 ', the adjustment cell Cx becomes the cell C3.
And the voltage of the cell C3 and the adjustment cell Cx are the same V
It becomes 3.5.

When t = 0.8, the first switch control circuit 10 is incremented by the count up of the timer counter 11.
Turns on the bidirectional switches S13 and S22, and the cell C
Select 4. Here, the voltage V3.5 of the adjustment cell Cx
Is larger, the second switch control circuit 12 turns on the unidirectional switches Sb and Sb ′. Adjustment cell C
Since the polarities of x and cell C4 are opposite, diodes D4 and D4 '
Is turned on, the adjustment cell Cx is discharged to the cell C4, and the voltages of the cell C4 and the adjustment cell Cx are the same V2.7.
It becomes 5.

When t = 0.9, the first switch control circuit 10 is turned on by the count value from the timer counter 11.
Turns on the bidirectional switches S13 and S23 to activate the cell C
Select 5. Here, the voltage V2.7 of the adjustment cell Cx is
Since 5 is larger, the second switch control circuit 12
The unidirectional switches Sb and Sb 'are turned on. Since the adjustment cell Cx and the cell C5 have the same polarity, the diodes D3, D
By turning on 3 ', the adjustment cell Cx becomes the cell C5.
Then, the cell voltages of the cell C5 and the adjustment cell Cx become the same V1.875.

Then, when t = 1.0 after one cycle, the first switch control circuit 10 turns on the bidirectional switches S11 and S21 to select the cell C1 again. Since the voltage V1.875 of the adjustment cell Cx is smaller, the second switch control circuit 12 turns on the unidirectional switches Sa and Sa ′. Since the adjustment cell Cx and the cell C1 have the same polarity, the diodes D1 and D1 ′ are turned on,
The cell C1 is discharged to the adjustment cell Cx, and the voltages of the cell C1 and the adjustment cell Cx become the same V2.9375.

As described above, if a cell is repeatedly selected from the assembled power source and connected to the adjustment cell Cx for charging and discharging,
The voltages of the cells approach each other, and are almost equalized at time t = 4. In addition, in the above, it was shown that the voltage of each cell becomes uniform by the adjusting cell in the state where the charging / discharging current does not flow in the assembled power source. The voltage rises or falls, but the same goes in the direction of homogenization.

The present embodiment is configured as described above, and bidirectional switches are connected to the terminals between the cells, and the bidirectional switches are switched one by one to select cells in order from the assembled power source to serve as adjustment cells. By making connections, the voltage of each cell can be made uniform, so that not only can each cell in the assembled power supply be prevented from overcharging but also over-discharging, the voltage detectors conventionally provided in each cell are required. Moreover, there is no need to detect a cell whose charge / discharge level has advanced by detecting the voltage.

Conventionally, in order to select a cell from the assembled power source, bidirectional switches are provided at both ends of one cell, but in the present embodiment, the number of bidirectional switches is about half that. It's done. Inexpensive unidirectional switch, timer counter and switch control circuit enable downsizing,
The effect of low cost is obtained. The timer counter 11 and the first switch control circuit 10 constitute connection control means.

In the present embodiment, the capacitor Ca in which a plurality of unit capacitors are connected in series has been described in order to increase the withstand voltage. However, even in the case of a battery, the unit capacitor is replaced by a unit battery as a cell, and the same as above. Thus, the voltage of the unit battery can be adjusted and made uniform.

Next, as a second embodiment, the capacitor C
Another configuration of a will be described. FIG. 5 shows another capacitor Ca
It is a figure which shows the internal structure of. As in FIG. 2, the bidirectional switch S is connected to the cells C1 to C5 connected in series as the assembled power source.
11 to S23 are additionally provided so that cells to be connected in parallel with the adjustment cell Cx can be selected from the assembled power supply.

The difference from FIG. 2 is that the connection terminals C and D are connected to the E and F ends of the adjustment cell Cx in order to match the polarities of the cell C and the adjustment cell Cx selected from the assembled power supply. Four bidirectional switches S1, S1 ′, S2, S2 ′. Each of these bidirectional switches is connected to the connection terminals C and D and the E and D ends of the adjustment cell Cx in a hooked manner. A second switch control circuit (second SW control circuit) 12A is provided to control the bidirectional switches S1 to S2 ′. Others are the same as those in the first embodiment shown in FIG.

Next, the flow of operation will be described with reference to the flowchart of FIG. First, in step 200, the timer counter 11 is initialized to start counting from a set value. In step 210, the first switch control circuit 10 and the second switch control circuit 1
2A selects and turns on the bidirectional switch according to the count value. For example, the first switch control circuit 10 initially selects the bidirectional switch S to select the cell C1.
11, S21 is turned on, and the second switch control circuit 12
A turns on the bidirectional switches S1 and S1 '. As a result, the cell C1 is connected to the adjustment cell Cx with the same polarity.

At this time, if the voltage Vx of the adjustment cell Cx is smaller, the cell C1 is discharged to the adjustment cell Cx,
Both voltages are the same. On the other hand, if the voltage Vx of the adjustment cell Cx is higher, the adjustment cell Cx is the cell C1.
Discharge to both voltages become the same. When the voltage Vx of the adjustment cell Cx and the voltage Vc of the cell C1 are the same,
Charge / discharge does not occur and voltage is maintained.

In step 220, the timer counter 11 counts up and the process returns to step 210.
Next, in step 210, the bidirectional switches S12 and S21 are turned on to select the cell C2. On the other hand, the second switch control circuit 12A turns on the bidirectional switches S2 and S2 ′ to match the polarities. As a result, the cell C2 and the adjustment cell are charged and discharged to have the same voltage.

Thereafter, as in the above, the timer counter 11
Based on the count value of the first switch control circuit 10
Selects the next cell C, the corresponding bidirectional switch is selected and turned on. Second switch control circuit 12
A turns on the bidirectional switches S1 and S1 ′ and S2 and S2 ′ alternately according to the polarity of the cell C that changes alternately. Timer counter 11 and first switch control circuit 1
0 constitutes a connection control means.

The present embodiment is configured as described above, and the bidirectional switches S1, S1 ', which are connected in a looped manner in order to connect the selected cell C and the adjustment cell Cx, are connected.
Since S2 and S2 'are used, the voltage detection circuit for detecting the voltage of the adjustment cell or the like as in the first embodiment is not necessary. According to this embodiment, the voltage of each cell can be made uniform as in the above case. Also, the device can be downsized. Also in this embodiment, a unit battery can be used as the cell instead of the unit capacitor.

In each of the above embodiments, when the timer counter counts up, the bidirectional switch is switched to select the next cell, so that charging or discharging is completed between the previous cell and the adjustment cell. In this case, a surge voltage may occur due to the interruption of the current.
Next, the prevention of this surge voltage will be described.

FIG. 7 shows a capacitor Ca having a surge voltage prevention function based on the structure shown in FIG. 2 in the first embodiment.
It is a figure which shows the internal structure of. 7, the difference from FIG. 2 is that a current detector 15 for detecting the presence or absence of a current flowing through the adjustment cell Cx or the current value is provided, and the timer counter 11B counts up based on this current information. . Other than that, it is the same as FIG.

FIG. 8 is a flow chart showing the flow of control in the above configuration. Steps 300 to 340 are step 1 of the flowchart shown in FIG.
The same as from 00 to step 140, the first switch control circuit 10 switches the bidirectional switches S11 to S23 according to the count value of the timer counter to select the cell C to be connected to the adjustment cell Cx. The voltage values of the selected cell C and the adjustment cell Cx are compared, and based on the comparison result, the second switch control circuit 12
Turns on the unidirectional switches Sa, Sa 'or Sb, Sb' to perform charging or discharging.

In the present control, thereafter, in step 350, the timer counter 11B inputs the detection value of the current detector 15 to check the current flowing in the adjustment cell Cx. When the current value becomes zero, the count is performed in step 360. Do up. In this way, when it is detected that no current is flowing in the adjustment cell Cx, the timer counter counts up, so when the current is flowing between the adjustment cell Cx and the cell C, the bidirectional Generation of surge voltage due to interruption of current is prevented without switching the switch. This eliminates the need for costly surge voltage countermeasures such as increasing the withstand voltage of the bidirectional switch.

Next, FIG. 9 shows a modification of the surge voltage prevention control. The difference from the control shown in FIG. 8 is that the cell is selected and connected to the adjustment cell only when the voltage in each cell in the assembled power supply varies. Steps 300 to 340 are the same as the control shown in FIG. 8, and according to the count value of the timer counter 11B, the cell C is selected from the assembled power source and connected to the adjustment cell Cx to perform charging / discharging.

Thereafter, in step 345, the second switch control circuit 12 compares the voltages of the cells to determine whether there is a voltage variation between the cells, and inputs the detected value from the current detector 15 to detect the current. It is determined whether the value I is smaller than a predetermined value I1 such that the surge voltage obtained by the following equation does not exceed the withstand voltage of the bidirectional switch. ΔV = dI1 / dt However, ΔV is a voltage set above the withstand voltage of the bidirectional switch. If the current value I is greater than or equal to the predetermined value I1, the process returns to step 345 after the determination at step 350, so the timer counter 11B does not count up until the current value I flowing through the adjustment cell Cx becomes zero. . Therefore, the previously selected cell remains connected to the adjustment cell Cx.

Then, when the current value I becomes zero and the timer counter 11B counts up in step 360, there is a voltage variation among the cells and the current flowing in the adjustment cell Cx is determined through the determination in step 345. If it is smaller than the predetermined value I1, the process returns to step 310 and a cell is newly selected according to the count value. In this way, when the current is flowing in the adjustment cell Cx, the timer counter 11B does not count up, so that there is no cell switching and the generation of surge voltage can be prevented.

When counting up, it is judged whether or not there is a voltage variation between the cells, and if there is a voltage variation and the current flowing through the adjusting cell is smaller than the predetermined value I1, the cells are switched. If there is no voltage variation even after the count-up, there is no cell switching, and the voltage between cells can be made more uniform. Further, even when the cell is switched, the current flowing through the adjustment cell Cx is checked, so that the surge voltage can be reliably prevented from occurring.

FIG. 10 shows a capacitor C having a surge voltage prevention function based on the structure shown in FIG. 5 in the second embodiment.
It is a figure which shows the internal structure of a. 10 is different from FIG. 5 in that a current detector 15 for detecting the presence or absence of a current flowing through the adjustment cell Cx or the current value is provided, and the timer counter 11B counts up based on this current information. . Others are the same as in FIG.

FIG. 11 is a flow chart showing the flow of control in the above configuration. Steps 200 and 210 are the same as those in the flowchart of FIG. When the timer counter 11B starts counting,
According to the count value, the first switch control circuit 10 turns on the bidirectional switch to select the cell C to be connected to the adjustment cell Cx. Charging / discharging is performed between the adjustment cell Cx and the selected cell C according to the voltage value of the selected cell C and the adjustment cell Cx.

In this control, after that, in step 215, the timer counter 11B inputs the detection value of the current detector 15 and checks the current flowing through the adjustment cell Cx.
When the current value becomes zero, step 220 is performed to count up. As described above, by detecting that no current is flowing in the adjustment cell and counting up, the bidirectional switch is switched when the current is flowing between the adjustment cell Cx and the cell C. Without the occurrence of a surge voltage due to the interruption of the current. Also in this case, costly surge voltage countermeasures such as increasing the withstand voltage of the bidirectional switch are not required.

Next, FIG. 12 shows a modification of the control shown in FIG. The difference from the control shown in FIG. 8 is that the cell is selected and connected to the adjustment cell only when the voltage in each cell in the assembled power supply varies. Step 200,
210 is the same as FIG. 11, the timer counter 11B starts counting, and according to the count value, the first counter
The switch control circuit 10 selects the cell C from the assembled power source and connects the cell C to the adjustment cell Cx for charging and discharging.

Thereafter, in step 214, the second switch control circuit 12A compares the voltages of the cells to determine whether there is a voltage variation between the cells, and inputs the detected value from the current detector 15 to detect the current. It is determined whether the value I is smaller than a predetermined value I1 at which the surge voltage does not exceed the withstand voltage of the bidirectional switch. If the current value I is greater than or equal to the predetermined value I1, the determination in step 215 is performed, and then step 2
Since returning to 14, the timer counter 11B does not count up until the current value I flowing through the adjustment cell Cx becomes zero. Therefore, the previously selected cell remains connected to the adjustment cell Cx.

Then, when the current value I becomes zero and the timer counter 11B counts up in step 220, there is a voltage variation between the cells and the current flowing in the adjustment cell Cx is determined through the determination in step 214. If it is smaller than the predetermined value I1, the process returns to step 210 and a cell is newly selected according to the count value. In this way, when the current is flowing in the adjustment cell Cx, the timer counter 11B does not count up, so that there is no cell switching and the generation of surge voltage can be prevented.

When counting up, it is determined whether or not there is a voltage variation between the cells, and if there is a voltage variation and the current flowing through the adjusting cell is smaller than the predetermined value I1, the cells are switched. If there is no voltage variation even after the count-up, there is no cell switching, and the voltage between cells can be made more uniform. Further, even when the cell is switched, the current flowing through the adjustment cell Cx is checked, so that the surge voltage can be reliably prevented from occurring.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a motor drive system.

FIG. 2 is a diagram showing an internal configuration of a capacitor.

FIG. 3 is a flowchart showing a control flow.

FIG. 4 is a diagram showing changes in the voltage of each cell due to the connection with the adjustment cell.

FIG. 5 is a diagram showing another example of the internal configuration of a capacitor.

FIG. 6 is a flowchart showing the flow of control.

FIG. 7 is a diagram showing an internal configuration of a capacitor provided with a surge current prevention function.

FIG. 8 is a flowchart showing a control flow.

FIG. 9 is a flowchart showing a modified example of control.

FIG. 10 is a diagram showing another example of the internal configuration of a capacitor provided with a surge current prevention function.

FIG. 11 is a flowchart showing a control flow.

FIG. 12 is a flowchart showing a modified example of control.

[Explanation of symbols]

C1 to C5 cells Cx adjustment cell S11-S23 bidirectional switch D12, D34 Diode array Sa, Sa ', Sb, Sb' unidirectional switch 10 First switch control circuit 11, 11A timer counter 12, 12A Second switch control circuit

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2G016 CB21 CB31 CC01 CC07 CC10                       CC12 CC21 CC23 CD09 CD10                 5G003 AA04 BA03 CA04 CA14 GA01                       GB06 GC04 GC05                 5H030 AA03 AA04 AA09 AS20 BB08                       FF42

Claims (4)

[Claims] 1. A charging / discharging control device for an assembled power supply, which is configured by connecting a plurality of batteries or capacitors in series as cells, and is capable of charging / discharging each cell of the assembled power supply, which is composed of batteries or capacitors. Adjusting cell, connecting means for individually connecting the adjusting cell to each cell of the assembled power supply, and controlling the connecting means so that the adjusting cell sequentially connects to each cell of the assembled power supply. A charge / discharge control device comprising: a connection control means. 2. A current detection means for detecting a charge / discharge current flowing between the adjustment cell and a cell of the assembled power supply connected to the adjustment cell is provided, and the connection control means is provided for the charge / discharge current. The charge / discharge control device according to claim 1, wherein the connection timing of the connection means is controlled based on the above. 3. The connecting means is a plurality of bidirectional switches, one end of each of which is connected to both ends of the assembled power supply and a connection end between cells, and the other end of each bidirectional switch is one end of the assembled power supply. Alternately from the side, the two cells are connected to the two connection terminals, and by closing two adjacent bidirectional switches, it is possible to select the cells to be connected to the connection terminals from the assembled power source. The charge / discharge control device according to claim 1, wherein a switch for polarity matching is connected between both ends of the adjustment cell. 4. The connecting means is a plurality of bidirectional switches each having one end connected to both ends of the assembled power source and a connection end between cells, and the other end of each bidirectional switch is one end of the assembled power source. Alternately from the side, the two cells are connected to the two connection terminals, and by closing two adjacent bidirectional switches, it is possible to select the cells to be connected to the connection terminals from the assembled power source. A charge control circuit and a discharge control circuit are provided between both ends of the adjustment cell, and the charge control circuit is for adjusting the polarities of the switch for controlling the charging current, the adjustment cell, and the selected cell. It is configured by a diode array, and the discharge control circuit is configured by a switch for controlling a discharge current, a diode array for matching the polarities of the adjustment cell and the selected cell. The charge and discharge control device according to claim 1 or 2.