JP5140470B2 - Series cell voltage balance correction circuit - Google Patents

Description

  The present invention relates to a voltage balance correction circuit for series cells, and more particularly to a technique that is effective when a plurality of storage cells such as secondary batteries and capacitors are connected in series.

  In many cases, a large number of storage cells such as secondary batteries and capacitors are connected in series. For example, in motive power sources for electric vehicles or power storage systems for load leveling, tens to hundreds of cells are often connected in series.

  In such a case, when voltage variation occurs between the cells, charging is restricted in the cell having the highest voltage, and discharging is restricted in the cell having the lowest voltage, resulting in deterioration of battery utilization efficiency. This problem becomes more prominent as the number of series connections increases. Therefore, equalization of the voltage of each cell is an important issue when using the storage cells connected in series.

  As an effective means for equalizing the voltages of the storage cells connected in series, as shown in FIG. 7A, an inductor L1, first and second switching elements S1, S2, and a two-phase pulse generator 11 is known (see, for example, Patent Documents 1 and 2).

  In the drawing, one end of the inductor L1 is connected to an intermediate connection point N1 between the first cell E1 and the second cell E2 forming two series cells. The first switching element S1 is interposed between the other end of the inductor L1 and one series connection end of the two cells E1 and E2 to form a switching circuit.

  Similarly, the second switching element S2 is interposed between the other end of the inductor L1 and the other series connection end of the two cells E1 and E2 to form a switching circuit. The two-phase pulse generator 11 generates square wave pulse signals + Φ1 and −Φ1 complementary to each other (positive and negative signs indicate logic or phase polarity, the same shall apply hereinafter) to generate the first and second switching elements S1 and S2. Complementary on / off.

  FIG. 2B shows an operation waveform chart in the main part of the voltage balance correction circuit. In the figure, when the voltage of the first cell E1 is higher than that of the second cell E2 (E1> E2), when S1 is on, the first cell E1 transfers to the inductor L1, and E1-S1-L1 The inductor current Li is charged (stored) in the direction of the solid arrow in the current path of −N1.

  Thereafter, when S1 is turned off and S2 is turned on, the inductor current Li charged in the inductor L1 is discharged through the current path N1-E2-S2-L1. This discharge is performed while charging the second cell E2.

  Contrary to the above, when the voltage of the second cell E2 is higher than that of the first cell E1 (E1 <E2), when S2 is on, the second cell E2 switches to the inductor L1 and E2 The inductor current Li is charged in the direction of the broken line arrow through the current path of -N1-L1-S2.

  Thereafter, when S2 is turned off and S1 is turned on, the inductor current Li charged in the inductor L1 is discharged through the current path of S1-E1-N1-L1. This discharge is performed while charging the first cell E1.

  As described above, electrical energy is transferred between the two cells E1 and E2 via the inductor L1. Thereby, the voltages of the cells E1, E2 are equalized.

  In this equalization operation, the inductor current iL decreases with time due to discharge, but when this discharge current becomes zero, a charging current in a direction opposite to the discharge current flows. Therefore, when the voltages of the two cells E1 and E2 are in a substantially equal balance state (E1≈E2), the inductor current iL is discharged and charged approximately equal amounts for each ON period of S1 and S2. . That is, the transfer of electrical energy performed via the inductor L1 is performed approximately equally between the two cells E1 and E2. Thereby, a voltage balance state is maintained.

However, the voltage balance correction circuit described above has the following problems.
That is, in the voltage balance correction circuit described above, for example, as shown in FIG. 7B, charging and discharging of the inductor current iL are performed even in a balanced state where the voltages of the two cells E1 and E2 are substantially equal. It ’s done just as it was before it was in balance. That is, the voltage balance correction circuit is always in a full operation state regardless of whether or not the balance correction is necessary.

  The charging and discharging of the inductor current iL involve some power loss due to impedance components such as resistances parasitic on the inductor L1 and the switching elements S1 and S2, for example. For this reason, the voltage balance correction circuit that always operates in the same manner regardless of the necessity of balance correction has a problem that there is a lot of wasted power loss.

  Therefore, as shown in FIG. 8, the present inventor variably sets the ON period (tw) of the first and second switching elements S1 and S2 depending on whether or not the necessity of balance correction is necessary, We studied a technique to reduce the power loss associated with the balance correction.

  This technique is disclosed as Patent Document 3, but, as shown in the figure, the duty widths tw (the ON periods of S1 and S2) of the control pulse signals Φ1 and Φ2 of the first and second switching elements S1 and S2 ) Can be variably controlled in accordance with the voltage difference Vx between the first cell E1 and the second cell E2 forming two series cells, thereby avoiding excessive operation that increases power loss.

  FIG. 8 shows an operation waveform chart in the main part of the balance correction circuit disclosed in Patent Document 3, in which (a) and (e) are between the first cell E1 and the second cell E2. The operation when a relatively large voltage difference appears in (E1> E2 or E1 <E2) is shown.

  In this case, the first switching elements S1 and S2 are alternately turned on and off at a constant cycle (tw + td). As a result, a charging period for charging the inductor current iL from the one cell E1 (or E2) to the inductor L1 and a discharging period for charging the other cell E2 (or E1) with the inductor current iL are alternately switched and set. The

  Furthermore, the charging / discharging period (tw) in which one of S1 and S2 is turned on is set to be sufficiently longer than the suspension period td in which both S1 and S2 are turned off. As a result, the amount of charge (electric energy) from the cell E1 (or E2) to the cell E2 (or E1) performed via the inductor L1 increases, and the voltage between the cells E1 and E2 is rapidly equalized. Become so.

  (B) and (d) show operations when the voltage difference between the two cells E1 and E2 is reduced (E1≈E2), respectively. In this case, the switching elements S1 and S2 are turned on / off at a constant cycle, but the charge / discharge period (tw) in which either S1 or S2 is turned on is shortened, and instead, both S1 and S2 are turned off. The pause period td is set longer.

  (C) shows the operation (E1 = E2) when the voltages of the cells E1, E2 are perfectly balanced. In this case, both of the switching elements S1 and S2 continue to be in the off state, and only the idle period td in which charging / discharging of the inductor L1 is not performed at all is performed.

As described above, when the voltage difference Vx between the two cells E1 and E2 is reduced, the power loss is increased by setting the idle period td in which both the first and second switching elements S1 and S2 are turned off. Excessive operation can be avoided. Thereby, the voltage of the some electrical storage cell connected in series can be equalized efficiently, without accompanying a big power loss.
JP 2001-185229 A JP 2006-67742 A JP2008-17605

  However, in the above-described conventional technique, the pulse signals Φ1 and Φ2 for making the switching elements S1 and S2 on / off-controlled as described above according to the voltage difference Vx between the two cells E1 and E2 are generated. There is a need. For this purpose, as described in Patent Document 3, an analog processing system that performs complex waveform processing operations such as triangular waveform generation, analog gate control, level shift, and phase inversion is required. Such an analog processing system has a problem that its configuration is complicated and it is difficult to make an IC.

  The present invention solves the above-described problems, and an object of the present invention is to generate a large amount of electric power by using a simple, small-scale circuit suitable for IC integration with a plurality of storage cells connected in series. An object of the present invention is to provide a series cell voltage balance correction circuit capable of efficiently equalizing without loss.

  Other objects and configurations of the present invention will be clarified in the description of the present specification and the accompanying drawings.

The solution provided by the present invention is as follows.
(1) In order to equalize the voltages of a plurality of power storage cells connected in series, one end is connected to an intermediate connection point between the first cell and the second cell that form two series cells in the order of series connection. A first switching element that forms an open / close circuit between one series end of the two series cells and the other end of the inductor, the other series end of the two series cells, and the inductor A second switching element that forms an open / close circuit interposed between the other end of
By alternately turning on and off the first and second switching elements, a charging period in which the inductor current is charged from one cell to the inductor, and the inductor current is discharged through a path for charging the other cell. A voltage balance correction circuit for a series cell configured to alternately switch and set a discharge period,
Outputs the first one-shot multivibrator regulator, a second single pulse signal is triggered driven at the falling of the first single pulse signal to output a first single pulse signal is periodically triggered drive a second one-shot multivibrator regulator,
The first switching element and the second switching element are alternately turned on / off using the first single pulse signal and the second single pulse signal, and the voltage difference between the two cells is set. detecting, voltage balance for series-connected cells, characterized by variably controlling the operating conditions of the one-shot multivibrator regulator so as to enlarge the pulse width of each single pulse signal in response to an increase of the detected value with the detection value Correction circuit.

(2) In the above means (1) comprises an absolute value detecting circuit for outputting an absolute value of the voltage difference between the two cells, single pulse signal of the one-shot multivibrator regulator output voltage of the absolute value detection circuit A voltage balance correction circuit for a series cell, characterized by controlling the pulse width of the cell.

  (3) In the means (1) or (2), the polarity detection circuit for detecting the polarity of the voltage difference between the two cells, and the first switching element and the second switching by the detection output of the polarity detection circuit A voltage balance correction circuit for a series cell, comprising a signal switching circuit for switching and setting the order of ON / OFF operation of elements.

In any one of (4) above means (1) to (3), the one-shot multivibrator regulator, by being connected through a resistor element between the control voltage to be a predetermined power supply voltage and a variable set A capacitor element that is steadily charged with a voltage difference between the two voltages, and a transistor that is turned on when a voltage that appears at a high potential side terminal of the capacitor element is equal to or higher than a predetermined threshold value. When the low potential side terminal of the transistor is temporarily switched to the reference potential, the transistor is triggered to be turned off for a period of time using the voltage difference as a variable element to generate a single pulse signal. A voltage balance correction circuit for the series cell.

(5) In any of the above means (1) to (4), detects a current flowing through the inductor, single pulse of the so this current does not exceed a predetermined limit value the first one-shot multivibrator regulator A voltage balance correction circuit for a series cell, which performs feedback control to shorten or limit a signal width.

  (6) In any one of the means (1) to (5), a voltage difference between the two cells is amplified by a differential amplifier, and an absolute value of the differential amplified output voltage is detected to detect the one-shot multi A voltage balance correction circuit for a series cell, wherein a pulse width control voltage of a vibrator is obtained and a polarity detection signal of the voltage difference is obtained by saturation amplification of the differential amplification output with a high gain single input amplifier .

  The voltages of a plurality of storage cells connected in series can be efficiently equalized without a large power loss with a simple, small-scale circuit suitable for IC integration.

 The operations / effects other than the above will be clarified in the description of the present specification and the accompanying drawings.

  FIG. 1 shows a first embodiment of a voltage balance correction circuit to which the technique of the present invention is applied. The voltage balance correction circuit shown in FIG. 1 equalizes each voltage of a plurality of storage cells connected in series, and includes an inductor L1, first and second switching elements S1, S2, and a correction control circuit 20. Is provided.

  One end of the inductor L1 is connected to an intermediate connection point N1 between the first cell E1 and the second cell E2 that form two series cells in the order of series connection. The other end is connected to a common connection point of the first and second switching elements S1, S2.

  The first switching element S1 is interposed between one series connection end of the two cells E1 and E2 and the other end of the inductor L1 to form a switching circuit. The second switching element S2 is interposed between the other series connection end of the two cells E1 and E2 and the other end of the inductor L1 to form a switching circuit.

  The correction control circuit 20 performs control to alternately turn on / off the first switching element S1 and the second switching element S2 in order to perform voltage balance correction of the two cells E1, E2. The correction control circuit 20 includes resistors R1 and R2, a pulse oscillator 21, first and second one-shot multivibrators 22 and 23, an inverter (polarity inverting circuit) 24, an analog adder 25, and a differential amplifier circuit 26. 27, an absolute value detection circuit 28, a signal switching circuit 30, and the like.

  The resistors R1 and R2 form a voltage dividing circuit that equally divides the series voltage of the two cells E1 and E2. For this reason, the resistors R1 and R2 are set to be equal. The differential amplifier circuits 26 and 27 linearly amplify the voltage difference (Vm−Vn) between the voltage Vm appearing at the intermediate connection point N1 of the cells E1 and E2 and the divided voltage Vn of the resistors R1 and R2 with a predetermined gain.

  The output voltage Vx of the differential amplifier circuit 26 is converted into a direct current by the absolute value detection circuit 28 and then applied to the one-shot multivibrators 22 and 23 as a pulse width control voltage. The absolute value detection circuit 28 is configured using, for example, a diode full-wave rectification circuit, and outputs a DC voltage reflecting the absolute value level of the output voltage Vx.

  Another differential amplifier circuit 27 outputs the polarity detection signal a of the voltage difference (Vm−Vn) by saturating and amplifying the voltage difference (Vm−Vn) with a sufficiently large gain. The polarity detection signal a is a kind of binary signal that takes a positive or negative constant value (saturation value).

The one-shot multivibrators 22 and 23 are also called monostable multivibrators or monomultivibrators. As shown in FIG. 2, the single-shot pulse signals p1 and t2 having predetermined pulse widths t1 and t2 when a trigger is input as shown in FIG. p2 is output.
In this case, the first one-shot multivibrator 22 is periodically triggered by a reference pulse signal CK having a fixed period generated by the pulse oscillator 21, and outputs a first single pulse signal p1 having a predetermined pulse width t1. .

The second one-shot multivibrator 22 is triggered by the falling edge of the first single pulse signal p1, and outputs a second single pulse signal p2 having a predetermined pulse width t2.
The polarity of the second single pulse signal p2 is inverted by the inverter 24, and then analog addition is performed by the analog adder 25 with the first single pulse signal p1.

  By this addition, as shown in FIG. 2, a composite pulse signal p3 in which a pulse signal p1 having an amplitude on the plus side and a pulse signal p2 having an amplitude on the minus side appear continuously is obtained. The composite pulse signal p3 becomes pulse signals Φ1 and Φ2 for alternately turning on / off the first switching element S1 and the second switching element S2 via the signal switching circuit 30.

  The pulse widths t1 and t2 of the first and second single pulse signals p1 and p2 are variably controlled by the output voltage of the absolute value detection circuit 28. This variable control is the total time of the two pulse widths t1 and t2. The width (t1 + t2) is performed in a range that is always shorter than the cycle T of the reference pulse signal CK. That is, the first single pulse signal p1 and the second single pulse signal p2 are always generated alternately without overlapping each other. For this purpose, the one-shot multivibrators 22 and 23 may be configured so that the pulse widths t1 and t2 of the single pulse signals p1 and p2 are less than half of the period T.

  The signal switching circuit 30 includes an analog multiplier 31 and a logic inverter 32, and the on / off operation order of the first switching element S1 and the second switching element S2 is determined according to the plus / minus polarity of the polarity detection signal a. Change the setting.

  That is, as shown in FIG. 2, when the voltages of the cells E1 and E2 are E2> E1, the polarity detection signal a has a positive polarity (a> 0). In this case, the composite pulse signal p3 has a composite pulse waveform in which the first single pulse signal p1 having an amplitude on the positive side is followed by the second single pulse signal p2 having an amplitude on the negative side.

  The first single pulse signal p1 that swings to the plus side becomes a pulse signal Φ2 that turns on the second switching element S2. As a result, the inductor current iL flows from E2 to the inductor L1.

When the first single pulse signal p1 falls and the first switching element S1 returns to OFF, the polarity of the second single pulse signal p2 is inverted by the inverter 32, thereby turning on the first switching element S1. The pulse signal Φ1 to be generated. Thereby, the inductor current iL is discharged through the charging path E1.
With the above operation cycle, balance correction is performed by charging from E2 to E1.

  On the other hand, as shown in FIG. 2, when the voltages of the cells E1 and E2 are E1> E2, the polarity detection signal a has a negative polarity (a <0). In this case, the composite pulse signal p3 has a composite pulse waveform in which the first single pulse signal p1 having an amplitude on the minus side is followed by the second single pulse signal p2 having an amplitude on the plus side.

  The first single pulse signal p1 having an amplitude on the minus side is inverted in polarity by the inverter 32 to become a pulse signal Φ1 for turning on the first switching element S1. As a result, the inductor current iL flows from E2 to the inductor L1.

When the first single pulse signal p1 falls and the first switching element S1 returns to OFF, the second single pulse signal p2 becomes a pulse signal Φ2 for turning on the second switching element S2. Thereby, the inductor current iL is discharged through the charging path E2.
According to the above operation cycle, balance correction by charging from E1 to E2 is performed.

  The main part of the voltage balance correction circuit described above is composed of two one-shot multivibrators 22 and 23. However, complicated processing operations such as triangular waveform generation, analog gate control, level shift and phase inversion are performed. There is no need for an analog processing system to perform.

  Therefore, the voltages of a plurality of storage cells connected in series can be efficiently equalized with a simple, small-scale, and suitable circuit-integrated circuit without a large power loss.

Further, in the illustrated embodiment, includes an absolute value detection circuit 28 which outputs the absolute value of the voltage difference between the two cells E1, E2, the one-shot multivibrator output voltage of the absolute value detection circuit 28 (Vx) The pulse widths t1 and t2 of the single pulse signals p1 and p2 of the modulators 22 and 23 are controlled. From this, the on-period tw (=) of the switching elements S1 and S2 based on the voltage difference between the cells E1 and E2 t1 + t2) The control can be performed easily and reliably.

  Similarly, in order to detect the polarity of the voltage difference between the two cells E1 and E2, a polarity detection circuit by the differential amplifier 27 is provided, and the first switching element S1 is detected by the detection output (a) of this polarity detection circuit. And the signal switching circuit 30 for switching the on / off operation order of the second switching element S2, which also greatly contributes to the simplification of the circuit configuration.

  FIG. 3 shows a specific circuit example of the one-shot multivibrators 22 and 23 that are particularly effective for use in the voltage balance correction circuit of the present invention.

  The one-shot multivibrators 22 and 23 shown in the figure include npn bipolar transistors Q1 and Q2, a trigger switching element Sx, capacitive elements C1 and C2 forming time constant elements, and resistive elements R11, R12, R21, R22, and R23. , And a diode D11 and the like.

  In the figure, capacitive elements C1 and C2 are respectively connected between a predetermined power supply voltage + Vcc and a variably set control voltage Vx via resistance elements R11-R12 and R21-R22. The battery is constantly charged with a voltage difference (Vcc-Vx).

  In a steady state in which the trigger switching element Sx is kept off, the voltage appearing on the high potential side terminal of the capacitive element C1 becomes equal to or higher than a predetermined threshold value, whereby the transistor Q1 forming the first one-shot multivibrator 22 Is supplied with a base current via a resistor R12. As a result, the transistor Q1 is steadily turned on, and the single pulse signal p1 taken out from its collector maintains the low level. That is, the single pulse signal p1 is not output.

  The transistor Q2 forming the second one-shot multivibrator 23 is supplied with the base current via the resistor R22 when the voltage appearing at the high potential side terminal of the capacitive element C1 becomes equal to or higher than a predetermined threshold value. As a result, the transistor Q2 is steadily turned on, and the single pulse signal p2 taken out from its collector maintains the low level. That is, the single pulse signal p2 is not output.

  Here, when the trigger switching element Sx is temporarily turned on by an external signal (CK), the low potential side terminal of the capacitive element C1 is connected to the signal ground, and C1 is previously set to Vx and the low potential side is Since the battery is charged in the + direction, a trigger that is turned off only for a time having the voltage difference (Vcc + Vx) as a variable element is performed, and the single pulse signal p1 rises to a high level only during the off period. That is, the single pulse signal p1 is output.

  Thereafter, when the capacitive element C1 is charged and the voltage between the base and emitter of Q1 (Vbe) reaches a voltage at which it is turned on, the transistor Q1 returns from the off state to the on state. When Q1 is turned on, the low-potential side terminal of the capacitive element C2 is switched to the signal ground, and this time, the transistor Q2 is triggered to turn off only for the time using the voltage difference (Vcc + Vx) as a variable element. Thus, the single pulse signal p2 rises to a high level only during the off period. That is, the single pulse signal p2 is output.

  As described above, in the present invention, the first and second one-shot multivibrators 22 and 23 are used for the main part thereof, but these are few by using a circuit as shown in FIG. It can be constituted by the number of elements and a very simple circuit.

  Note that the diode D11 in FIG. 3 operates as a clamp circuit that suppresses the control voltage (Vx) to be equal to or lower than the power supply voltage (+ Vcc).

  In the circuit shown in FIG. 1, rectifier diodes D1 and D2 that perform switching operations according to the current direction are connected in parallel to the switching elements S1 and S2, respectively. The diodes D1 and D2 are in the reverse direction with respect to the voltages of the cells E1 and E2, but are in the forward direction with respect to the inductor current iL.

  If the inductor current iL remains during the period when both the switching elements S1 and S2 are off, the residual inductor current iL can continue to flow through the diode D1 or D2. Thereby, the inductor current iL once generated in the inductor L1 can be used for the voltage equalization operation without waste, and the generation of the surge voltage generated when the inductor current iL is cut off can be surely suppressed.

Use of power MOS-FETs is suitable as the switching elements S1 and S2. In power MOS-FETs, a diode parallel to the source and drain is normally formed. This diode is called a parasitic diode or an internal diode. By using this diode as the diodes D1 and D2, the circuit configuration can be simplified and the number of elements can be reduced.
FIG. 4 shows a second embodiment of the present invention. Focusing on the difference from the above-described embodiment, in the embodiment shown in the figure, a current detection resistor Rs is inserted in series with the inductor L1, and the current detection voltage divided across the resistor Rs is differential amplifier. amplified by 33, after direct current the amplified voltage by the absolute value detection circuit 34, give the first one-shot multivibrator regulator 22 via a buffer circuit 35 as a pulse width control signal.

In this case, the pulse width control signal is given as a feedback control signal as the inductor current iL to shorten the single pulse signal width t1 of the first one-shot multivibrator regulator 22 so as not to exceed a predetermined limit value .

  As a result, even when the voltage difference between the cells E1 and E2 is abnormally large, the inductor L1 is prevented from flowing an excessive inductor current iL, and a small inductor L1 having a small current capacity can be used.

  In the above configuration, a constant detection threshold element is interposed in the detection path of the inductor current iL, and the single pulse signal width t1 is shortened or expanded only when the inductor current iL is about to exceed a predetermined limit value. It is good to make it stop.

  FIG. 5 shows a third embodiment of the present invention. Focusing on the difference from the above-described embodiment, in the embodiment shown in the figure, the voltage difference between the two cells E1 and E2 is amplified by the differential amplifier 26, and the absolute value of this differentially amplified output voltage is detected. Thus, the pulse width control voltage of the one-shot multivibrators 22 and 23 is obtained, and the differential amplification output voltage is saturated and amplified by the high-gain single input amplifier 271 to obtain the voltage detection polarity detection signal a. I have to.

  With such a configuration, it is possible to use a single-input amplifier that is simpler in configuration and operation than the differential amplifier, thereby further simplifying the circuit configuration.

  FIG. 6 shows a connection example when the voltage balance correction circuit described above is applied to three or more multi-series cells E1 to E6,. As shown in the figure, in the voltage balance correction in three or more multi-series cells E1 to E6,..., An inductor L1 is installed for each connection point between the cells, and the first and second for each inductor L1. Switching elements S1 and S2 are provided, and the correction control circuit 20 described above is provided for each of the switching elements S1 and S2, so that voltage balance correction is performed among all the cells E1 to E6,. be able to.

  As described above, the present invention has been described based on the representative embodiments, but the present invention can have various modes other than those described above.

  The voltages of a plurality of storage cells connected in series can be efficiently equalized without a large power loss with a simple, small-scale circuit suitable for IC integration.

1 is a circuit diagram showing a first embodiment of a voltage balance correction circuit according to the present invention. FIG. 2 is an operation waveform chart in a main part of the balance correction circuit shown in FIG. 1. It is a specific circuit diagram of a one-shot multivibrator effective for use in the voltage balance correction circuit of the present invention. It is a circuit diagram which shows 2nd Embodiment of the voltage balance correction circuit by this invention. It is a circuit diagram which shows 3rd Embodiment of the voltage balance correction circuit by this invention. It is a circuit diagram which shows the case where the voltage balance correction circuit of this invention is applied to three or more multi-series cells. It is the circuit diagram and operation waveform chart which show the 1st structural example of the conventional voltage balance correction circuit. It is a principal part waveform chart which shows the 2nd structural example of the conventional voltage balance correction circuit.

Explanation of symbols

20 Correction Control Circuit 21 Pulse Oscillator 22 First One-shot Multivibrator 23 Second One-shot Multivibrator 24 Inverter (polarity inversion)
25 Analog Adder 26, 27 Differential Amplifier 271 High Gain Single Input Amplifier 28 Absolute Value Detection Circuit 30 Signal Switching Circuit 31 Analog Multiplier 32 Logical Inverter 33 Differential Amplifier 34 Absolute Value Detection Circuit 35 Buffer Circuit a Polarity Detection Signal C1, C2 Capacitance element forming time constant element CK Reference pulse signal D1, D2, D11 Diode E1-E6 Cell iL Inductor current L1 Inductor N1 Intermediate connection point p1 First single pulse signal p2 Second single pulse signal p3 Composite Pulse signal Q1, Q2 Transistors R1, R2 Resistance (voltage divider)
R11 to R23 Resistance S1 First switching element S2 Second switching element Sx Trigger switching element Vx Detection voltage between cells (pulse width control voltage)
+ Vcc Power supply voltage Φ1, Φ2 Pulse signal

Claims (6)

In order to equalize the voltages of a plurality of storage cells connected in series, a first cell that forms two series cells back and forth in the order of series connection, and an inductor having one end connected to an intermediate connection point of the second cells, A first switching element that forms an open / close circuit between one series end of the two series cells and the other end of the inductor; the other series end of the two series cells; and the other end of the inductor And a second switching element that forms an open / close circuit interposed therebetween,
By alternately turning on and off the first and second switching elements, a charging period in which the inductor current is charged from one cell to the inductor, and the inductor current is discharged through a path for charging the other cell. A voltage balance correction circuit for a series cell configured to alternately switch and set a discharge period,
Outputs the first one-shot multivibrator regulator, a second single pulse signal is triggered driven at the falling of the first single pulse signal to output a first single pulse signal is periodically triggered drive a second one-shot multivibrator regulator,
The first switching element and the second switching element are alternately turned on / off using the first single pulse signal and the second single pulse signal, and the voltage difference between the two cells is set. detecting, voltage balance for series-connected cells, characterized by variably controlling the operating conditions of the one-shot multivibrator regulator so as to enlarge the pulse width of each single pulse signal in response to an increase of the detected value with the detection value Correction circuit. According to claim 1, comprising an absolute value detecting circuit for outputting an absolute value of the voltage difference between the two cells, the output voltage of the absolute value detecting circuit controls the pulse width of the single pulse signal of the one-shot multivibrator regulator A voltage balance correction circuit for a series cell, characterized by: 3. The polarity detection circuit for detecting the polarity of the voltage difference between the two cells and the on / off operation sequence of the first switching element and the second switching element according to the detection output of the polarity detection circuit according to claim 1 or 2. A voltage balance correction circuit for a series cell, comprising a signal switching circuit for switching and setting. Constant in any one of claims 1 to 3, the one-shot multivibrator regulator is the voltage difference between the voltage by being connected via a resistor element between the control voltage to be a predetermined power supply voltage and a variable set And a transistor that is turned on when the voltage appearing at the high potential side terminal of the capacitive element is equal to or higher than a predetermined threshold, and the low potential side terminal of the capacitive element is used as a reference. A voltage balance of a series cell, characterized in that a single pulse signal is generated by triggering the transistor to be turned off for a period of time with the voltage difference as a variable element by temporarily switching to a potential Correction circuit. In any one of claims 1 to 4, detects the current flowing through the inductor, reducing or limiting the single pulse signal width of the first one-shot multivibrator regulator so that this current does not exceed a predetermined limit value A series cell voltage balance correction circuit characterized by performing such feedback control. 6. The voltage difference between the two cells is amplified by a differential amplifier according to claim 1, and an absolute value of the differential amplification output voltage is detected to obtain a pulse width control voltage of the one-shot multivibrator. A voltage balance correction circuit for a series cell, wherein the polarity detection signal of the voltage difference is obtained by saturation amplification of the differential amplification output with a high-gain single input amplifier.

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