DE102007023023A1 - Circuit arrangement and method for operating an energy storage device - Google Patents

Abstract

A circuit arrangement can be coupled to an energy storage arrangement which comprises at least two energy storage cells (Cz), which are arranged electrically in series with one another. The circuit arrangement comprises an energy buffer (Cs) having a first terminal (A1) and a second terminal (A2). For each energy storage cell (Cz) of the energy storage device, the circuit arrangement comprises in each case a first switch (SWa), which is arranged electrically between a first terminal of the respective energy storage cell (Cz) and the first terminal (A1) of the energy buffer (Cs), and comprises for each Energy storage cell (Cz) of the energy storage device each have a second switch (SWb), which is arranged electrically between a second terminal of the respective energy storage cell (Cz) and the second terminal (A2) of the intermediate energy storage (Cs). Furthermore, the circuit arrangement comprises a control unit (ST), which is coupled to the respective first switches (SWa) and the respective second switches (SWb). The control unit (ST) is designed to generate control signals for driving the first and the second switches (SWa, SWb).

Description

The The invention relates to a circuit arrangement and method for operating an energy storage device, the at least two energy storage cells includes, which are arranged electrically in series with each other.

such Energy storage arrangements are used, for example, in motor vehicles, especially in hybrid vehicles used for storage and deployment of energy during short-term high power consumption or power requirement. Short term high power falls For example, in a braking operation, in which the kinetic energy is converted into electrical energy. Short-term high demand for Performance prevails, for example, with an acceleration support means Electric motor. As energy storage cells, for example, double-layer capacitors intended. However, due to their low dielectric strength must In general, several double-layer capacitors are electrically in Row arranged to each other, for a motor vehicle electrical system required withstand voltage of, for example, about 60 volts too to reach. Different self-discharge of the individual double-layer capacitors however, may affect the function of the energy storage device.

The The object of the invention is a circuit arrangement and method to provide an energy storage device that are simple.

The Task is solved by the characteristics of the independent Claims. Advantageous developments of the invention are characterized in the subclaims.

According to one In the first aspect, the invention is characterized by a circuit arrangement which with a Energiespei cheranordnung can be coupled, at least comprises two energy storage cells that are electrically connected in series are arranged. The circuit arrangement comprises an energy buffer, having a first port and a second port. The circuit arrangement comprises for each energy storage cell the energy storage device each have a first switch, the electrically between a first terminal of the respective energy storage cell and the first terminal of the energy buffer is, and includes for each energy storage cell of the energy storage device each one second switch, which is electrically connected between a second terminal the respective energy storage cell and the second terminal of Energy buffer is arranged. Furthermore, the circuit arrangement comprises a control unit connected to the respective first switches and is coupled to the respective second switches. The control unit is configured to generate control signals for driving the first and second switches.

Of the Advantage is that by suitably driving the switch charge very simply from at least one of the at least two energy storage cells via a Caching in the intermediate energy storage to at least one another of the at least two energy storage cells transmitted can be. This provides a simple and reliable charge equalization between energy storage cells possible. Furthermore, the circuit arrangement is simple and can be implemented simply and inexpensively and integrable. The energy buffer is, for example formed as a capacitor. The energy storage cells are for example as capacitors and in particular as double-layer capacitors educated.

In an advantageous embodiment, the circuit arrangement comprises an inductance element that electrically in series with the energy buffer and electrically between the intermediate energy storage and the respective first or second switch is arranged. Through the inductance element, the intermediate energy storage and the respective at least one of at least two energy storage cells, a resonant circuit is formed. This has the advantage of having a current for transmission of electrical Charge a sinusoidal Has history and thereby current peaks in the switching operations of first and / or second switches are reliably avoided. The Circuit arrangement thereby has a high electromagnetic compatibility on. The transferring The charge can be done very efficiently. The circuit arrangement can so continue to work with a high efficiency.

In In this context, it is advantageous if the control unit is formed is to capture a size that representative is for a current through the inductance element. The circuit arrangement comprises a zero crossing detection unit for detecting a zero crossing of the current. The circuit arrangement is further configured to generate the control signals depending on the each detected zero crossing of the current. The circuit arrangement is preferred configured to generate the control signals such that the closing and / or opening of the first and second switches substantially respectively to each detected Zero crossing of the current takes place. This allows the transfer the charge is particularly efficient and the circuit has so a particularly high efficiency.

In this context it is advantageous if the control unit comprises a vibration phase detection unit for detecting a vibration phase of the current and is designed to generate the control signals as a function of the respective detected oscillation phase of the current. As a result, a particularly reliable operating behavior is possible. By way of example, the oscillation phase recognition unit is designed as a differentiation unit or comprises such. In particular, the respective oscillation phase can then be identified on the basis of a respective sign of the differentiated current.

In a further advantageous embodiment, the circuit arrangement can be coupled with at least one energy source.

The Circuit arrangement includes for each of the at least one energy source at least one source switch, the electrical between each one connection of the power source and the first or the second terminal of the energy buffer is arranged. The advantage is that extra charge is very easy from the at least one energy source to at least one of the at least two Transfer energy storage cells can be. The additional Charging can by targeted switching the switch targeted those Energy storage cells supplied be that extra Need charge, this means, their voltage compared to the respective voltage of others of at least two energy storage cells is low. The charging of the energy storage cells can be done so very efficiently become. The at least one energy source is for example as a battery, in particular a motor vehicle battery, or accumulator educated.

In In a further advantageous embodiment, the circuit arrangement comprises a voltage detection unit connected to the energy buffer is coupled and is adapted to determine a measurement voltage dependent from a voltage of the energy buffer. By suitable Switching the switch can change the voltage of each one or more the at least two energy storage cells very easily by the Voltage detection unit can be determined in the form of the measured voltage. It does not have to be for Each of the at least two energy storage cells has its own voltage detection unit be provided. The circuit arrangement is very simple. Further, depending from the determined voltages of the energy storage cells very efficient the charge balance can be controlled.

According to one second aspect, the invention is characterized by a method for operating an energy storage device having at least two Energy storage cells arranged electrically in series with each other are. For Each energy storage cell of the energy storage device is in each case a first Switch provided which is electrically connected between a first terminal the respective energy storage cell and a first connection of an energy buffer is arranged. Further, for each energy storage cell of the energy storage device each one second switch provided electrically between a second Connection of the respective energy storage cell and a second connection the energy buffer is arranged. In the process will be the first switch and the second switch, one of the at least two Energy storage cells or two different of the at least two Energy storage cells are assigned, closed for transfer of electrical charge from the at least one of the at least two energy storage cells to the energy buffer. The first Switch and / or the second switch are opened again. Further be the first switch and the second switch, the at least another of the at least two energy storage cells assigned are closed to transfer of electrical charge from the energy buffer to the at least another of the at least two energy storage cells.

Of the Advantage is that by this driving the switch charge very much simply from at least one of the at least two energy storage cells via a Caching in the intermediate energy storage to at least one another of the at least two energy storage cells transmitted can be. This provides a simple and reliable charge equalization between energy storage cells possible.

In an advantageous embodiment of the second aspect has Electricity in transferring the electric charge a sinusoidal Course on. A stream representing Size is detected. A respective time of a zero crossing of the current becomes dependent determined by the size. The respective first and second switches are opened or closed depending on the respective time of the determined zero crossing. Prefers For example, the first and second switches are substantially each closed to the ever Weil detected zero crossing of the current or open. Thereby can transfer the charge particularly efficient and with a particularly high efficiency respectively.

In In this context, it is advantageous if a vibration phase of electricity depending on the size determined and the respective first and second switches are opened or be closed dependent from the respectively determined oscillation phase. This is one particularly reliable Operating behavior possible.

In In this context, it is advantageous if a course of the Stream representing size differentiated is and the respective oscillation phase of the current depends on a sign of the differentiated size is determined or the respective Vibration phase of the current by the sign of the differentiated Size formed becomes. The advantage is that thereby the respective relevant oscillation phase easy and reliable can be recognized.

In a further advantageous embodiment of the second aspect is provided at least one energy source. For each of the at least one energy source Furthermore, at least one source switch is provided which is electrically between each one terminal of the power source and the first or the second terminal of the energy buffer is arranged. In the method, the at least one source switch is at least one of the at least one power source closed for transmission of electrical charge from this at least one energy source to the energy cache. The at least one source switch is open and the first switch and the second switch, one of the at least two energy storage cells or two different ones of the at least two Energy storage cells are assigned, are closed for transfer of electrical charge from the energy buffer to the at least one of the at least two energy storage cells. The advantage is, that extra Charge very easily from the at least one source of energy to at least one of the at least two energy storage cells can be transmitted. The additional charge can be selectively fed to those energy storage cells, the extra one Need charge, this means, their voltage compared to the respective voltage of the other at least two sources of energy is low. The charging of the energy storage cells can be done so very efficiently become.

According to one third aspect, the invention is characterized by a method for operating an energy storage device having at least two Energy storage cells arranged electrically in series with each other are. For Each energy storage cell of the energy storage device is one each first switch is provided, which electrically between a first Connection of the respective energy storage cell and a first connection a power buffer is arranged. For every energy storage cell the energy storage device is further each a second switch provided electrically between a second terminal of the respective energy storage cell and a second terminal of the Energy buffer is arranged. In the process will be the first switch and the second switch, one of the at least two Energy storage cells or two different of the at least two Energy storage cells are assigned, closed for transfer of electrical charge between the at least one of the at least two energy storage cells and the energy buffer. A Size is captured, which is representative is for a voltage of the energy buffer. The tension of each one or more of the at least two energy storage cells can be so can be determined very easily and can therefore also very easily monitored become. This is particularly advantageous for controlling the charge balance according to the method of the second aspect. The charge balance can be so very easy and efficiently dependent be controlled by the determined voltages. It is preferred therefore, the method according to the second Aspect executed, after the method according to the third As pect performed and a deviation or inequality to be corrected the for every energy storage cell detected voltage was detected.

In an advantageous embodiment of the third aspect, the size is only after a predetermined minimum waiting time has elapsed after closing the detected first and second switches. The default minimum wait time is preferably set so long that any vibration has essentially subsided and a voltage of the energy buffer essentially a voltage of the at least one of the at least is two energy storage cells. Thereby is a very precise Determining the voltage of at least one of the at least two Energy storage cells possible dependent from the captured size, the representative is for the voltage of the energy buffer.

embodiments The invention are explained below with reference to the schematic drawings. It demonstrate:

1 a circuit arrangement and an energy storage arrangement,

2 the energy storage arrangement and a more detailed illustration of an embodiment of the circuit arrangement,

3 a flowchart of a first program and

4 a flowchart of a second program.

elements same construction or function are cross-figurative with the same Provided with reference numerals.

An energy storage device comprises at least two energy storage cells Cz, which are arranged electrically in series with each other ( 1 ). The energy storage cells Cz are preferably designed as capacitors and are in particular designed as double-layer capacitors. By way of example, a first capacitor C1, a second capacitor C2, further capacitors (not shown), a capacitor Cn-1 and an nth capacitor Cn are provided in the energy storage arrangement, where n represents the number of energy storage cells Cz, that is to say in particular the capacitors. Such an energy storage arrangement is used, for example, in vehicles and in particular in motor vehicles for storing and providing energy, in particular for a short-term high power consumption or power requirement.

by virtue of limited dielectric strength of the energy storage cells Cz and in particular, the double-layer capacitors are preferably more Energy storage cells Cz arranged electrically in series and form thereby the energy storage arrangement. For example, one is maximum permissible Voltage of the energy storage cells Cz about 2.5 to 3 volts. For a 42nd Volt vehicle electrical system, for example, a dielectric strength required by about 60 volts. The energy storage device comprises then, for example, about 20 to 25 such energy storage cells Cz, which are arranged electrically in series with each other, that is, the number n of the energy storage cells Cz is about 20 to 25. The energy storage device can but also be designed differently.

however the energy storage cells Cz generally have a different high self-discharge. This creates a charge imbalance over time between different energy storage cells Cz of the energy storage device, that at different voltages of the different energy storage cells Cz leads. As a result, the function of the energy storage arrangement considerably impaired become.

A Circuit arrangement is provided, which is designed for electrical Coupling with the energy storage device. The circuit arrangement comprises a temporary energy store Cs, which may be referred to, for example, as a capacitor is formed. The energy cache Cs has a first terminal A1 and a second terminal A2. The circuit arrangement further comprises for each energy storage cell Cz the energy storage device has a first switch SWa and a second switch SWb. The respective first switch SWa is electric between a first terminal of the respective energy storage cell Cz and the first terminal A1 of the intermediate energy storage Cs arranged. Accordingly, the respective second switch SWb is electrically connected between a second terminal of the respective energy storage cell Cz and the second terminal A2 of the intermediate energy storage Cs arranged. In particular, a first switch SW1a of the first capacitor C1 and a second switch SW1b of the first capacitor C1 are provided and are correspondingly a first switch SW2a of the second capacitor C2, a second switch SW2b of the second capacitor C2, are further, not shown switch provided and are a first Switch SWn - 1a of the capacitor Cn - 1, a second switch SWn-1b of the capacitor Cn - 1, a first switch SWna of the nth capacitor Cn and a second one Switch SWnb of the nth capacitor Cn provided. The switches are preferably formed as transistors, but can be formed differently.

Prefers The circuit also includes a resistor R and a inductance L, for example, a coil that is electrically in series with each other and electrically in series with the energy buffer Cs between them and the switches are arranged. The energy cache Cs and the inductance element L form a resonant circuit.

Further the circuit arrangement comprises a control unit ST, the output side is coupled to the switches and which is formed, a respective one To generate control signal for driving the respective switch. The circuit arrangement is preferably designed to be a current i or a current i representing To capture size and the control unit ST is preferably formed, the respective Actuation signal dependent from the detected current i or dependent on the current i representing To produce size. by virtue of of the resonant circuit may be a time course of the current i sinusoidal. By suitably driving the switches can charge transport between at least one of the energy storage cells Cz and the energy buffer Cs thereby done very efficiently and with high efficiency. Further can so current spikes are avoided, so the circuitry thereby can have a high electromagnetic compatibility.

2 shows an embodiment of the circuit arrangement in more detail. The variable representing the current i is, for example, a voltage drop across the resistor R. The resistor R is coupled, for example, to a differential amplifier unit DV, which is included, for example, by the control unit ST. The differential amplifier unit DV, the voltage drop across the resistor R is supplied on the input side. The differential amplifier unit DV is designed to detect and amplify the voltage drop and for providing the amplified voltage drop on the output side.

The Control unit ST comprises a zero crossing detection unit ND and a switching logic unit SL. The differential amplifier unit DV is the output side with the zero crossing detection unit ND coupled. The zero crossing detection unit ND is designed a respective zero crossing of the current i depending on the input side supplied increased Determine voltage drop, that is, the respective zero crossing dependent from the current i representing Size to be determined.

The Zero crossing detection unit ND is the output side with the logic unit SL coupled. The zero crossing detection unit ND is designed the logic unit SL the respective detected zero crossing to signal. The logic unit SL is the output side with a driver unit TR coupled, in turn, the output side with the respective switches is coupled. The logic unit SL is configured to generate a respective drive signal to Driving the respective switch depending on the respective signaled Zero crossing of the current i. In particular, the switching logic unit SL configured to generate the respective drive signal in such a way, that the respective switch substantially to a respective Time of the zero crossing of the current i is opened or closed. The driver unit TR includes, for example, for each switch to be controlled a power amplifier. Thereby can be achieved that the respective switch very quickly opened or can be closed.

The Circuit arrangement preferably also includes a vibration phase detection unit. The vibration phase detection unit is designed to detect a vibration phase and in particular for detecting a vibration phase with respect to the respective zero crossing of the respective oscillation, this means, whether the oscillation at the respective zero crossing of a positive Half-wave changes to a negative half-wave or vice versa. For example, the vibration phase detection unit is one Differentiation unit DIFF formed. The differentiation unit DIFF is coupled on the input side to the differential amplifier unit DV and is output coupled to the switching logic unit SL. The Differentiating unit DIFF is designed to differentiate the time course of the input side supplied amplified voltage drop across the Resistance R and to find a sign of this differentiated Course. The calculated sign represents the respective oscillation phase and the switching logic unit SL is supplied on the input side, for Example in the form of a one or zero level. The logic unit SL is preferably designed, the respective drive signal depending on the respectively detected vibration phase and depending on the respectively detected To create zero crossing.

In addition to the energy storage arrangement, it is also possible to provide at least one energy source BAT, which is embodied, for example, as a battery and in particular as a vehicle battery. The circuit arrangement can be coupled to the at least one energy source BAT. The circuit arrangement comprises at least one source switch SWBAT, which is arranged electrically between the energy source BAT and the first or second connection A1, A2 of the energy buffer Cs. In the in 2 In the example shown, the source switch SWBAT is electrically arranged between the energy source BAT and the first terminal A1 of the energy buffer Cs. The energy source BAT, like the energy storage device, is also electrically coupled to a reference potential GND.

The Circuit arrangement preferably further comprises a voltage detection unit SH on, for example, comprises a sample-holding member or as a sample-holding member is trained. The voltage detection unit SH is input side is coupled to the energy buffer Cs and is formed for detecting a voltage of the intermediate energy storage Cs and for determining and output-side provision of a measuring voltage Um. The voltage detection unit SH is designed to detect the measuring voltage To dependent supplied from the input side Voltage of the energy buffer Cs. The measuring voltage is Um representative for the Voltage of the energy buffer Cs. By suitable driving the switch is representative of the voltage of the energy buffer Cs for one Voltage of one or more of the energy storage cells Cz of the energy storage device. Accordingly, the measurement voltage Um may be representative of the voltage one or more of the energy storage cells Cz of the energy storage device.

Preferably, the control unit ST is designed to generate the respective drive signals as a function of the measuring voltages Um respectively detected for the energy storage cells Cz. In particular, the switching logic unit SL is designed to select the respective opening or closing switch depending on these measured voltages. This allows a very efficient and targeted charge balance between different energy storage cells Cz of the energy storage device or a targeted charging of energy storage cells Cz with charges that the En source BAT are removable.

3 shows a flowchart of a first program. The program is used to charge balance between different energy storage cells Cz the energy storage device or the targeted charging of energy storage cells Cz with charges that can be removed from the energy source BAT. The program starts in a step S1. In a step S2, the first switch SWa and the second switch SWb are selected such that at least one of the energy storage cells Cz, which is to be removed from the charge, is arranged electrically between them. For example, the first switch SW2a of the second capacitor C2 and the second switch SW2b of the second capacitor C2 are selected. Then, the second capacitor C2 is selected for the discharge of charge. However, for example, the first switch SW1a of the first capacitor C1 and the second switch SW2b of the second capacitor C2 may also be selected, for example. Then, a series connection of the first and second capacitors C1, C2 is selected for the discharge of charge. Accordingly, more than two energy storage cells Cz can be selected for the removal of charge. Instead of selecting one of the first or second switches SWa, SWb, the at least one source switch SWBAT can also be selected in step S2 in order to select the energy source BAT for the removal of charge.

In a step S3, the selected switches closed. By closing The switch can be a current flow and thus a charge transport take place when the voltage of the selected at least one energy storage cell Cz or the energy source BAT and the voltage of the energy giezwischenspeichers Cs are different. The selection of the first and the second switch SWa, SWb or the source switch SWBAT is therefore in the step S2 preferably such that the voltage of the intermediate energy storage Cs is lower than the voltage of the selected at least one energy storage cell Cz or the energy source BAT. Then the current i flows from the selected at least an energy storage cell Cz or the power source BAT to the Energy cache Cs.

Preferably In step S4, a counter is generated Z initialized and started. In a step S5 is preferably the current i or the quantity representing the current i detected. In a step S6, it is then preferably checked whether the current i or the magnitude i representing the current i Zero crossing and whether for the completion of the charge removal provided vibration phase is present. The one for ending the charge removal intended vibration phase is in particular by a negative Sign of the time derivative of the current i or the representing the current i Size formed. Further can be checked whether the counter Z a predetermined counter value has reached. Does the counter Z the default counter value not reached and no zero crossing was detected or is the for the Completion of the charge withdrawal intended vibration phase, then the program is preferably continued in a step S7. In step S7, the counter becomes Z preferably in the direction of the predetermined counter value is incremented or decremented. The program is continued in step S5.

Has been however, in step S6, the zero crossing is detected and is the for the Preceding the charge extraction intended phase before or has the counter Z is the preset counter value reached, then the program is continued in a step S8. In step S8, the selected first and second switches SWa, SWb open. In a step S9, according to the step S2, the first and the second switch SWa, SWb is selected such that electrically therebetween at least one of the energy storage cells Cz is arranged, the Charge supplied shall be. According to the step S3, these selected switches closed in a step S10. Closing the selected switches is preferably performed substantially at the time of zero crossing After opening the previously for the removal of the charge closed switch in step S8, So without significant time delay. However, it must be ensured that the driving of the switches such that none of the energy storage cells Cz short-circuited becomes.

In Step S11 is preferably performed in accordance with Step S4 the counter Z initialized and started. In a step S12 is preferably in step S5, the current i or the current i representing Size recorded. In a step S13 is preferably according to the step S6 checks if the Current i or the size i representing the current i Has zero crossing and whether intended for a termination of the charge supply Vibration phase is present. The for a termination of the charge supply provided Oscillation phase is in particular by a positive sign the time derivative of the current i or the current i representing Size formed. It can also be checked whether the counter Z is the preset counter value has reached. The default counter value is preferably equal to the predetermined used in steps S4 to S7 Counter value. The default counter values can but also be specified differently.

Has the counter Z is the preset counter value not reached and no zero crossing was detected or is the for the Exit the charge feeder provided vibration phase is not present, then the program is preferred in a step S14 which corresponds to the step S7. The program is continued in step S12. But was in the zero crossing is detected in step S13 and is the one for the termination the charge supply provided Vibration phase before or the counter Z has the predetermined counter value reached, then the program is continued in a step S15, which corresponds to step S8. In step S15, the selected first and second switches SWa, SWb open and the program is ended in a step S16.

Of the counter Z essentially serves to remove the charge or the Respectively the charge after a predetermined period of time since the respective Start of the counter Z in step S4 or in step S11 if so the zero crossing is not detected in time and / or the required Vibration phase is not present in time. The predetermined period of time and accordingly, the predetermined counter value is preferable specified so that the resulting time since the respective Start of the counter Z longer is as half a period of the preferably sinusoidal oscillation of the current i during the Charge transport between the energy buffer Cs and the in each case at least one energy storage cell Cz. Instead of the counter Z can also be provided a time measuring device, which after expiration the respective predetermined period of time the removal or feeding the Charge finished.

4 shows a flowchart of a second program. The second program is used to determine the measurement voltage Um depending on the voltage of the intermediate energy storage Cs so that the measurement voltage Um preferably represents the voltage of at least one of the energy storage cells Cz. The program starts in a step S20. In a step S21, the first switch SWa and the second switch SWb are selected such that at least one of the energy storage cells Cz is arranged between them, the voltage of which is to be determined in the form of the measuring voltage Um. In a step S22, these selected switches are closed. By closing the switches, the current flow and thus the charge transport can take place if the voltage of the selected at least one energy storage cell Cz and the voltage of the energy buffer Cs are different. By charge transport, these voltages can be equalized.

To is preferably waited until the charge transport and the equalization of the voltages is essentially complete. For example For this purpose, the counter Z is initialized and started in a step S23. In a step S24, it is preferably checked whether the counter Z is a predetermined first counter value has reached. If this condition is not fulfilled, then the counter Z is preferred in a step S25 in the direction of the predetermined first counter value incremented or decremented. Is the condition in step S24 however fulfilled, then the program is continued in a step S26.

Of the predetermined first counter value is preferably predetermined so that a resulting period of time since the start of the counter Z is long enough to equalize the voltages of the intermediate energy storage Cs and the at least one energy storage cell Cz to allow. The default first counter value is preferably set so that the resulting period of time several oscillation periods of the preferably sinusoidal current i includes. In particular, the predetermined first counter value dependent from a desired one Precision specified with which the measuring voltage To the actual Voltage of at least one energy storage cell Cz represent should.

In step S26, the selected first and second switches SWa, SWb are opened. The voltage measurement takes place, for example, by means of the voltage detection unit SH. It can be provided for the voltage detection unit SH to be connected to the energy buffer Cs only when required, that is to say when the voltage of the energy buffer Cs is to be detected, by closing at least one further switch associated with the voltage detection unit SH. The voltage detection unit SH generally requires a minimum waiting period for detecting the voltage. Preferably, this minimum waiting period is waited until the voltage is detected and the measuring voltage Um can be provided. For example, counter Z is initialized and started in a step S28. In a step S29, it is preferably checked whether the counter Z has reached a predetermined second counter value. If this condition is not fulfilled, then the counter Z is preferably incremented or decremented in a step S30 in the direction of the predetermined second counter value. However, if the condition is met in step S29, the detection of the voltage of the energy buffer Cs is terminated in a step S31 and, if appropriate, the further switch associated with the at least one voltage detection unit SH is opened. The measured voltage Um, which is determined as a function of the detected voltage of the energy buffer Cs, becomes the voltage on the output side socket SH provided. The program is ended in a step S32.

Instead of of the meter Z can also be provided in the second program, a time measuring device be after a predetermined first and second time period waiting for the voltage of the intermediate energy storage Cs to equalize and the at least one energy storage cell Cz or Waiting for the end of detecting the voltage of the energy buffer Cz finished. Preferably, the predetermined first time period and accordingly the predetermined first counter value for the Equalizing the voltages of the intermediate energy storage Cs and the at least one energy storage cell Cz given longer than the predetermined second time period and according to the predetermined second counter value for the Detecting the voltage of the energy buffer Cs. Especially is the predetermined second period of time at least as long as the Minimum waiting time for detecting the voltage of the intermediate energy storage Cs. If available one enough if necessary, fast voltage detection unit SH can also to dispense with the steps S28 to S30.

Preferably, the program is according to 4 executed before the program according to 3 is performed. Preferably, the program is according to 4 for at least two and preferably for all of the at least two energy storage cells Cz of the energy storage arrangement, in order to determine the respective selection of the first and second switches SWa, SWb in steps S2 and S9 of the program according to FIG 3 depending on the respectively measured voltage to perform.

Claims (13)

Circuitry, - The with an energy storage device can be coupled, which comprises at least two energy storage cells (Cz), which are arranged electrically in series with each other, - the one Energy buffer (Cs), which has a first port (A1) and a second terminal (A2), - for each energy storage cell (Cz) of the energy storage device each have a first switch (SWa) which electrically connects between a first terminal of the respective one Energy storage cell (Cz) and the first port (A1) of the energy buffer (Cs) is arranged, and the for each energy storage cell (Cz) of the energy storage device respectively a second switch (SWb) electrically connected between one second connection of the respective energy storage cell (Cz) and the second terminal (A2) of the intermediate energy store (Cs) is and - the a control unit (ST) connected to the respective first switches (SWa) and the respective second switches (SWb) is coupled and which is designed to generate control signals for driving the first and second switches (SWa, SWb). Circuit arrangement according to claim 1, which is an inductance element (L) electrically connected in series with the energy buffer (Cs) and electrically between the energy buffer (Cs) and the respective first or second switch (SWa, SWb) is. Circuit arrangement according to Claim 2, in which the Control unit (ST) - educated is to capture a size that representative is for a current (i) through the inductance element (L), A zero crossing detection unit (ND) comprises for detecting a zero crossing of the current (i) and - educated is for generating the control signals depending on the respectively detected Zero crossing of the current (i). Circuit arrangement according to Claim 3, in which the Control unit (ST) - one Vibration phase detection unit comprises for detecting a vibration phase of electricity (i) and - educated is for generating the control signals depending on the respectively detected Vibration phase of the current (i). Circuit arrangement according to one of the preceding claims, - with at least one energy source (BAT) can be coupled and - for each of the at least one energy source (BAT) at least one source switch (SWBAT), which is electrically connected between each connection the energy source (BAT) and the first or the second connection (A1, A2) of the energy buffer (Cs) is arranged. Circuit arrangement according to one of the preceding claims, which a voltage detection unit (SH) connected to the energy buffer (Cs) is coupled and which is designed to determine a measurement voltage (Um) depending on a voltage of the energy buffer (Cs). Method for operating an energy storage device having at least two energy storage cells (Cz), which are arranged electrically in series with each other, wherein for each energy storage cell (Cz) of the energy storage device respectively a first switch (SWa) is provided which electrically zwi a first terminal of the respective energy storage cell (Cz) and a first terminal (A1) of an intermediate energy storage (Cs) is arranged, and for each energy storage cell (Cz) of the energy storage device each have a second switch (SWb) is provided, which electrically between a second terminal the respective energy storage cell (Cz) and a second terminal (A2) of the energy buffer (Cs) is arranged, in which - the first switch (SWa) and the second switch (SWb), one of the at least two energy storage cells (Cz) or two different the at least two energy storage cells (Cz) are associated, closed to transfer electrical charge from the at least one of the at least two energy storage cells (Cz) to the energy buffer (Cs), - the first switch (SWa) and / or the second switch (SWb ) and - the first switch (SWa) and the second switch (SWb), the at least one other which are associated with at least two energy storage cells (Cz), are closed to transfer electrical charge from the energy buffer (Cs) to the at least one other of the at least two energy storage cells (Cz). The method of claim 7, wherein - a stream (i) in the transfer the electric charge has a sinusoidal course, - a the Current (i) representing Size is recorded, - a respective one Time of a zero crossing of the current (i) depending on the size determined will and - the respective first and second switches (SWa, SWb) open or be closed depending on the respective time of the determined zero crossing. A method according to claim 8, wherein - a vibration phase of the current (i) depends on the size determined will and - the respective first and second switches (SWa, SWb) open or be closed depending on the respective determined vibration phase. The method of claim 9, wherein - a course which differentiates the quantity representing the stream (i) will and - the respective oscillation phase of the current (i) depending on a sign of differentiated size determined o is the respective oscillation phase of the current (i) through the Sign of the differentiated size is formed. Method according to one of claims 7 to 10, wherein at least an energy source (BAT) is provided and for each of the at least one Energy source (BAT) at least one source switch (SWBAT) provided is electrically connected between each one terminal of the power source (BAT) and the first or the second terminal (A1, A2) of the energy buffer (Cs) is arranged at the - The at least one source switch (SWBAT) closed at least one of the at least one energy source becomes transferring of electrical charge from this at least one energy source (BAT) to the energy buffer (Cs), - The at least one source switch (SWBAT) opened will and - of the first switch (SWa) and the second switch (SWb), one of the at least two energy storage cells (Cz) or two different associated with at least two energy storage cells (Cz), closed to transfer of electrical charge from the energy buffer (Cs) the at least one of the at least two energy storage cells (Cz). Method for operating an energy storage device with at least two energy storage cells (Cz) electrically in Row are arranged to each other, wherein for each energy storage cell (Cz) the energy storage arrangement is provided in each case a first switch (SWa) is electrically connected between a first terminal of the respective Energy storage cell (Cz) and a first terminal (A1) of a Energy buffer (Cs) is arranged, and for each energy storage cell (Cz) of the energy storage arrangement in each case a second switch (SWb) is provided, which is electrically connected between a second terminal the respective energy storage cell (Cz) and a second connection (A2) of the intermediate energy store (Cs) is arranged, in which - the first Switch (SWa) and the second switch (SWb), which is one of at least two energy storage cells (Cz) or two different ones of the at least two energy storage cells (Cz) are assigned to be closed to transfer of electrical charge between the at least one of the at least two energy storage cells (Cz) and the energy buffer (Cs), - one Size recorded that becomes representative is for one Voltage of the energy buffer (Cs). The method of claim 12, wherein the size is only after a predetermined minimum waiting time has elapsed after closing the first and second switches (SWa, SWb) is detected.