CN103296910B - Direct voltage capture device for energy storage device and method for generating direct voltage by energy storage device - Google Patents

Abstract

The invention relates to a DC voltage interception device (8) for an energy storage device (1), the energy storage device having a plurality of energy supply branches (Z) each having a plurality of energy storage modules ( 3), the DC voltage intercepting device has a first half-bridge circuit (9), the first half-bridge circuit has a plurality of first gathering terminals (8a, 8b, 8c), and the first gathering terminals are respectively connected to the energy storage device (1) coupled to one of the output terminals (1a, 1b, 1c), the DC voltage interception device also has a second half-bridge circuit (15) with a plurality of second aggregation terminals (8g, 8h, 8i), the second collecting terminal is coupled to one of the output terminals (1a, 1b, 1c) of the energy storage device (1), and the DC voltage interception device also has a step-up converter (14).

Description

DC voltage interception device of energy storage device and DC voltage generated by energy storage device method

technical field

The invention relates to a DC voltage interception device (Gleichspannungsabgriffsanordnung) for an energy storage device and a method for generating a DC voltage from an energy storage device, in particular in systems with battery direct inverters, for simultaneously feeding an electric motor supply and generate another potential for the DC grid.

Background technique

It can be seen that in the future not only in stationary applications, such as wind energy plants or solar plants, but also in vehicles, such as hybrid or electric vehicles, more electronic systems will be used, which combine new energy storage technologies with electric drives. technology combined.

The supply of multiphase currents in electric machines is usually carried out by means of an inverter in the form of a pulse inverter. For this purpose, the direct voltage provided by the direct voltage intermediate circuit can be converted into a polyphase alternating voltage, for example a three-phase alternating voltage. The direct voltage intermediate circuit is supplied here by a branch of the series-connected battery modules. In order to be able to meet the given power and energy requirements for the respective application, several battery modules are usually connected in series to form a traction battery.

The problem with this series circuit of several battery modules is that if a single battery module fails, the entire branch fails. Such a failure of the supply branch may lead to the failure of the entire system. In addition, temporary or permanent power drops of individual battery modules can lead to a power drop in the entire supply branch.

A battery system with integrated inverter function is described in document US 5,642,275 A1. This system is called multi-level cascaded inverter or battery direct inverter (Batteriedirektumrichter, BDI). Such a system consists of a DC power supply in the form of a branch of energy storage modules, which can be connected directly to an electric motor or to a grid. A single-phase or multi-phase supply voltage can be generated here. The energy storage module branch here has a plurality of energy storage modules connected in series, each energy storage module having at least one battery cell and an associated controllable coupling unit, which allows bridging the corresponding associated at least One battery cell, or at least one correspondingly associated battery cell, is connected to the corresponding branch of the energy storage module. In this case, the coupling unit can be designed in such a way that it also allows the connection of the respectively associated at least one battery cell into the corresponding energy storage module branch with reversed polarity, or also the disconnection of the corresponding energy storage module. branch road. By suitably controlling the coupling unit, for example by means of pulse width modulation, suitable phase signals can also be provided for controlling the phase output voltage, so that a separate pulse inverter can be dispensed with. The pulse inverters required for controlling the phase output voltages are thus integrated in so-called BDIs.

BDIs generally have a higher efficiency, higher failsafety and significantly lower harmonic content in their output voltage than conventional systems. This fail-safety is ensured in particular by the fact that faulty, failed or not fully functional battery cells can be bypassed in the power supply branch by suitably controlling their associated coupling units. The phase output voltage of an energy storage module branch can be varied and in particular adjusted stepwise by correspondingly controlling the coupling unit. The level of the output voltage is formed here from the voltages of the individual energy storage modules, wherein the maximum possible phase output voltage is determined by the sum of all energy storage modules of an energy storage module branch.

The documents DE 10 2010 027 857 A1 and DE 10 2010 027 861 A1 disclose, for example, battery direct inverters with a plurality of battery module strings, which can be connected directly to an electric machine.

A constant DC voltage is not provided at the output of the BDI, since the energy storage unit is divided into different energy storage modules and its coupling must be controlled in order to generate a potential in a targeted manner. Due to this division, DBI is basically not provided as a DC voltage source, such as for the power supply of the electric vehicle on-board grid.

A intercepting device for an energy storage device and a method for operating the energy storage device are therefore required in order to be able to intercept or generate another potential, in particular a direct current potential, during continuous operation of the energy storage device.

Contents of the invention

According to one aspect, the present invention provides a DC voltage interception device for an energy storage device, wherein the energy storage device has a plurality of energy supply branches, and the energy supply branches respectively have a plurality of energy storage modules, so that An alternating voltage is generated on a plurality of output terminals of the energy storage device, the direct current voltage intercepting device has a first half-bridge circuit, the first half-bridge circuit has a plurality of first gathering terminals, and the first gathering terminals are respectively connected to One of the output terminals of the energy storage device is coupled, and the DC voltage intercepting device also has a second half-bridge circuit, and the second half-bridge circuit has a plurality of second gathering terminals, and the second gathering terminals are respectively connected to the energy storage One of the output terminals of the device is coupled, and the DC voltage interception device also has a boost converter (Hochsetzsteller), the boost converter is coupled between the first half-bridge circuit and the second half-bridge circuit, and For this purpose, the step-up converter is designed to provide a direct voltage at the pick-up terminal of the direct-voltage pick-up device as a function of the potential difference between the first half-bridge circuit and the second half-bridge circuit.

According to another aspect, the present invention also provides an electric drive system, the system has an energy storage device, the energy storage device has a plurality of energy supply branches, and the energy supply branches respectively have a plurality of energy storage modules to An AC voltage is generated on output terminals of the energy storage device, the system also has a DC voltage interception device according to the invention, the first gathering terminal and the second gathering terminal of the DC voltage intercepting device are respectively connected to the energy storage device coupled to one of the output terminals of the device.

According to a further aspect, the invention provides a method for generating a DC voltage from an energy storage device, wherein the energy storage device has a plurality of energy supply branches each having a plurality of energy stores module to generate an alternating voltage at a plurality of output terminals of the energy storage device, the method having the step of intercepting a corresponding instantaneous highest potential at the output terminals of the energy storage device, having at the plurality of output terminals of the energy storage device The step of intercepting a corresponding instantaneous lowest potential on the terminal, having the step of boosting the potential difference between the corresponding instantaneous highest potential and the reference potential by using a boost converter, and providing a voltage related to the boosted potential difference a DC voltage step.

The idea of the invention is to couple a circuit to the output of an energy storage device, in particular a battery direct inverter, with which a DC voltage can be tapped from the output of the energy storage device. To this end, it is provided that two diode half-bridges are coupled to the output terminals of the energy storage device as accumulation devices, with which the instantaneous peak and instantaneous lowest potential. These two potentials have a potential difference which can be used to generate a DC voltage by means of a step-up converter. This DC voltage can then be used, for example, to supply intermediate circuit capacitors of the on-board electrical system.

A significant advantage of the DC voltage interception device is that the energy storage device can be used in an electric drive system without additional modifications, that is to say without intervention in the operation of the energy storage device. For example, when the energy storage device is used in an electric vehicle, a supply voltage for the electric drive and a DC voltage for the onboard electrical system of the electric vehicle can be generated simultaneously.

Advantageously, the number of components can be kept to a minimum by means of the aggregation of the DC voltage pick-up, since only one step-up converter is required in the DC voltage pick-up to supply the intermediate circuit capacitance of the on-board electrical system. This on the one hand reduces the component requirements and thus reduces the component space requirements and the system weight, especially in electric drive systems, and on the other hand switching losses can be minimized.

This circuit-technical additional outlay is advantageously insignificant. Furthermore, it has the advantage that the participating energy storage cell modules can be balanced during the generation of the DC voltage, that is, the balancing carried out during the operation of the energy storage device can be followed automatically depending on the state of charge and aging effects. To carry out the same loading on the individual energy storage unit modules, so that the energy storage modules are equally loaded, and thus the life and availability of the energy storage device are improved.

In addition, there is a significant advantage that a switching element, for example a semiconductor power switch, can be used in the boost converter which does not have to have reverse blocking capability, since the input voltage of the boost converter always has same polarity. This offers the advantage that power losses in the boost converter can be minimized.

By intercepting the respective instantaneously highest and instantaneously lowest potentials at the output terminals, the respectively instantaneously largest possible potential difference can be used to generate a DC voltage. In addition, a permanent connection of the DC voltage interception device to the reference potential rail of the energy storage device can be avoided.

According to an embodiment of the energy storage device of the present invention, the first half-bridge circuit may have a plurality of first diodes, and the first diodes are respectively coupled between the boost converter and a plurality of first aggregation terminals between one. In an advantageous embodiment, the first half-bridge circuit can have a plurality of first commutation inductors, the first commutation inductors are respectively coupled between a plurality of first diodes and the boost converter . Likewise, according to another embodiment of the energy storage device of the present invention, the second half-bridge circuit can have a plurality of second diodes, and the second diodes are respectively coupled between the boost converter and the plurality of second diodes. between one of the aggregate terminals. In an advantageous embodiment, the second half-bridge circuit can have a plurality of second commutation inductors, the second commutation inductors are respectively coupled between a plurality of second diodes and the boost converter . Corresponding potential fluctuations in the half-bridge circuit at the output terminals, in particular high-frequency fluctuations at specific points in time when the energy storage device is actuated, can thus be compensated or damped. In a preferred embodiment, the anodes of a plurality of first diodes are respectively coupled to the first collective terminal, and the cathodes of a plurality of second diodes are respectively coupled to the second collective terminal.

According to a further embodiment of the energy storage device according to the invention, the boost converter can have a converter inductor, an output diode, and a regulator switching element. In an advantageous embodiment, the regulator switching element can have a power semiconductor switch, for example a MOSFET switch or an IGBT switch. This has the advantage that it is possible to use switching elements which do not have to have a clear reverse blocking capability.

According to a further embodiment, the energy storage device according to the invention may comprise an intermediate circuit capacitor which is coupled between the pick-up terminals of the DC voltage pick-up device and which is designed for this purpose to provide generated output current pulses.

According to a further embodiment, the energy storage device according to the invention can have a first compensation diode, the anode of which is coupled to the reference potential busbar of the energy storage device and the cathode of which is coupled to a voltage boost converter. The first input terminal is coupled, and/or the energy storage device may have a second compensation diode, the cathode of which is coupled to the reference potential busbar of the energy storage device, and the anode of which is coupled to the boost converter One of the second input terminals is coupled. Especially in the case of small voltages at the input terminals of the energy storage device, this makes it possible to offset the n-phase motor with respect to the reference potential by raising or lowering the output voltage identically at the output terminals of the energy storage device neutral point potential. Otherwise, this is particularly advantageous if, for example, the stator voltage at the electric machine in the low rotational speed range is too low in order to provide the step-up converter with a sufficiently high input voltage. By means of the compensating diode, the potential at the collecting terminals of the first half-bridge circuit can always be kept at a minimum reference potential level, so that the boost is increased at the output terminals of the energy storage device by identically reducing the output voltage. The input voltage of the voltage converter, or the potential on the aggregation point of the second half-bridge circuit can always be kept at the highest potential level, so that the output voltage is increased by the same on the input terminals of the energy storage device. to increase the input voltage of the boost converter.

According to one embodiment of the method according to the invention, the method additionally comprises the step of supplying the intermediate circuit capacitor with the supplied DC voltage.

According to one embodiment of the method according to the invention, the method can be used to provide a DC voltage for an on-board electrical system of an electric vehicle with the electric drive system according to the invention.

For other features and advantages of embodiments of the present invention see the following description with reference to the accompanying drawings.

Description of drawings

in:

Figure 1 shows a schematic diagram of a system with an energy storage device;

Fig. 2 shows a schematic diagram of an energy storage module of the energy storage device;

Fig. 3 shows a schematic diagram of an energy storage module of the energy storage device;

Figure 4 shows a schematic diagram of a system with an energy storage device and a DC voltage interception device according to an embodiment of the present invention;

Figure 5 shows a schematic diagram of a system with an energy storage device and a DC voltage interception device according to another embodiment of the present invention; and

Fig. 6 shows a schematic diagram of a method for generating a DC voltage by an energy storage device according to another embodiment of the present invention.

detailed description

FIG. 1 shows a schematic diagram of a system 100 with an energy storage device 1 for changing the DC voltage provided in the energy storage module 3 into an n-phase AC voltage. The energy storage device 1 comprises a plurality of energy supply branches Z, three of which are shown by way of example in FIG. 1 , which are suitable for generating a three-phase alternating voltage, for example, for a rotating electrical machine 2 . However, any other number of energy supply branches Z is obviously also possible. The energy supply branch Z can have a plurality of energy storage modules 3 which are connected in series in the energy supply branch Z. For example, three energy storage modules 3 are shown per energy supply branch Z in FIG. 1 , but any other number of energy storage modules 3 is also possible. The energy storage device 1 has on each energy supply branch Z an output connection 1 a , 1 b and 1 c which is connected to a phase line 2 a , 2 b and 2 c respectively.

The system 100 can additionally include a control device 6, which is connected to the energy storage device 1, and by means of which the energy storage device 1 can be controlled to provide desired output voltage.

The energy storage module 3 each has two output terminals 3 a and 3 b , via which an output voltage of the energy storage module 3 can be supplied. Since the energy storage modules 3 are first connected in series, the output voltages of the energy storage modules 3 add up to form a total output voltage which can be provided at the corresponding output terminals 1 a , 1 b and 1 c of the energy storage device 1 .

An exemplary embodiment of this energy storage module 3 is shown in more detail in FIGS. 2 and 3 . The energy storage module 3 here contains a corresponding coupling device 7 which has a plurality of coupling units 7a, 7c and optionally 7b and 7d. The energy storage module 3 also includes a corresponding energy storage unit module 5, which has one or more energy storage units 5a to 5k connected in series.

The energy storage cell module 5 can have, for example, batteries 5 a to 5 k connected in series, for example lithium-ion batteries. The number of energy storage cells 5 a to 5 k is, for example, two in the energy storage module 3 shown in FIGS. 2 and 3 , but any other number of energy storage cells 5 a to 5 k is also possible.

The energy storage cell module 5 is connected to the input terminal of the associated coupling device 7 via a connection line. In FIG. 2 , the coupling device 7 is designed, for example, as a full-bridge circuit with two coupling units 7 a , 7 c and two coupling units 7 b , 7 d each. The coupling units 7 a , 7 b , 7 c , 7 d can each have an active switching element, such as a semiconductor switch, and a freewheeling diode connected in parallel thereto. It can be provided here that the coupling units 7 a , 7 b , 7 c , 7 d are designed as MOSFET switches or IGBT switches already having internal diodes. Alternatively, only two coupling units 7 a , 7 c can also be formed in each case, as shown by way of example in FIG. 3 , so that a half-bridge circuit is realized. The connection of the output terminals 3 a and 3 b can be selected here as shown in FIG. 3 . Or the output terminal 3 a can also be connected to the middle tap between the coupling units 7 a and 7 c, and the output terminal 3 b can be connected to the negative pole of the energy storage module 5 . In both cases, the output terminals 3 a and 3 b can also be interchanged.

The coupling units 7a, 7b, 7c, 7d can be controlled, for example by means of the control device 6 shown in FIG. , or the energy storage unit module 5 is bridged. Referring to FIG. 2 , the energy storage unit module 5 can, for example, be positively connected between the output terminals 3 a and 3 b in that the active switching elements of the coupling unit 7 d and the active switching elements of the coupling unit 7 a are arranged is in the closed state, while the other two active switching elements of the coupling units 7b and 7c are set in the open state. The bridging state can be set, for example, in that the two active switching elements of the coupling units 7 a and 7 b are set in the closed state, while the two active switching elements of the coupling units 7 c and 7 d are set in the open state. A second bridging state can be set in such a way that the two active switching elements of the coupling units 7a and 7b are kept open, while the two active switching elements of the coupling units 7c and 7d are set closed state. Finally, the energy storage cell module 5 can, for example, be connected inversely between the output terminals 3 a and 3 b in that the active switching element of the coupling unit 7 b and the active switching element of the coupling unit 7 c are set in the closed state , while the other two active switching elements of the coupling units 7a and 7d are set to the off state. By suitably controlling the coupling device 7 , several energy storage cell modules 5 of the energy storage module 3 can be integrated in a targeted manner and with any polarity in a series connection of an energy supply branch. Similar considerations can also be implemented correspondingly for the half-bridge circuit in FIG. 3 .

For example, the system 100 shown in FIG. 1 is used to power a three-phase motor 2 , for example in an electric drive system of an electric vehicle. However, it can also be provided that the energy storage device 1 is used to generate current for the supply network 2 . The energy supply branch Z can be connected at its neutral point-connected end to a reference potential 4 (reference potential busbar). The reference potential 4 can be, for example, a ground potential.

In order to generate a phase voltage between the output terminals 1 a , 1 b and 1 c on the one hand and the reference potential busbar 4 on the other, usually only a part of the energy storage cell modules 5 of the energy storage module 3 is required. Its coupling device 7 can be controlled in such a way that the total output voltage of an energy supply branch Z can be multiplied by the negative voltage of the single energy storage unit module 5 multiplied by the number of energy storage modules 3 and the multiplication of the single energy storage unit module 5 on the one hand. Between the positive voltage with the number of energy storage modules 3 and, on the other hand, between the negative rated current and the positive rated current of the individual energy storage modules 3 , the voltage/current regulation range is adjusted stepwise in a rectangular voltage/current regulation range.

As shown in FIG. 1 , such an energy storage device 1 has different potentials at the output terminals 1 a , 1 b , 1 c at different operating times and thus cannot be used simply as a DC voltage source. Especially in the electric drive system of an electric vehicle, it is generally desired that the energy storage device 1 is used to supply power to the vehicle's on-board power grid, such as a high-voltage on-board power grid or a low-voltage on-board power grid. A DC voltage interception device is thus provided, which is designed for this purpose to be connected to an energy storage device 1 and supplied by it to provide a DC voltage, for example for an on-board electrical system of an electric vehicle.

FIG. 4 shows a schematic diagram of a system 200 with an energy storage device 1 and such a DC voltage interception device 8 . The DC voltage pick-up device 8 is connected to the energy storage device 1 on the one hand via first collecting connections 8 a , 8 b and 8 c and on the other hand is coupled thereto via second collecting connections 8 g , 8 h and 8 i. A direct voltage U _ZK of the direct voltage disconnect device 8 can be tapped at the disconnect terminals 8 e and 8 f. For example, a DC voltage converter (not shown) can be connected to the disconnect terminals 8e and 8f for the on-board electrical system of an electric vehicle, or the voltage U _ZK between the disconnect terminals 8e and 8f can be balanced appropriately. In the case of the voltage of the grid on the vehicle, it can also be directly connected to the grid on the vehicle.

The direct voltage pick-up device 8 has a first half-bridge circuit 9 , which is coupled via first collector connections 8 a , 8 b , 8 c to output connections 1 a , 1 b , 1 c of the energy storage device 1 . The first collective connections 8 a , 8 b , 8 c can be coupled here, for example, to the phase lines 2 a , 2 b and 2 c of the system 200 . The first half-bridge circuit 9 can have a plurality of first diodes 9a, which are coupled to one of the aggregation terminals 8a, 8b, 8c, respectively, such that the corresponding anodes of the diodes 9a are connected to the phase line 2a. , 2b or 2c phase coupling. The cathodes of the diodes 9 a can be connected together to a common collection point of the first half-bridge circuit 9 . The instantaneous highest potential of the phase line 2 a , 2 b or 2 c is thus present at the point of convergence of the half-bridge circuit 9 . Additionally or alternatively, a plurality of first commutation inductance coils 9 b can be provided, which are respectively coupled between the first diode 9 a of the first half-bridge circuit 9 and the gathering point. The first commutation inductance coil 9b here can buffer potential fluctuations, which may sometimes occur in the corresponding phase line 2a, 2b or 2c due to the step-by-step potential change determined by the control, so that the first two-pole Tube 9a is less loaded due to the constant rectification process.

Similarly, the direct voltage intercept device 8 has a second half-bridge circuit 15 , which is coupled to the output terminals 1 a , 1 b , 1 c of the energy storage device 1 via second collection terminals 8 g , 8 h , 8 i in each case. The second collective connections 8 g , 8 h , 8 i can be coupled here, for example, to the phase lines 2 a , 2 b and 2 c of the system 200 . The second half-bridge circuit 15 may have a plurality of second diodes 15a, which are respectively coupled to one of the second aggregation terminals 8g, 8h, 8i, such that the corresponding cathodes of the diodes 15a are connected to the phase Lines 2a, 2b or 2c are coupled. The anodes of the diodes 15a can be connected together to a common junction of the second half-bridge circuit 15 . The instantaneous minimum potential of the phase line 2 a , 2 b or 2 c is thus present at the point of convergence of the second half-bridge circuit 15 . Additionally or alternatively, a plurality of second commutation inductance coils 15 b can be provided, which are respectively coupled between the second diode 15 a of the second half-bridge circuit 15 and the gathering point. The second commutating inductance coil 15b here can buffer potential fluctuations, which may sometimes occur in the corresponding phase line 2a, 2b or 2c due to the step-by-step potential change determined by the control, so that the second two-pole The tube 15a is less loaded due to the constant commutation process.

Half-bridge circuits 9 and 15 are each coupled via their junction to one of the two input terminals of boost converter 14 . A potential difference exists between the aggregation terminals, which can be boosted by the boost converter 14 . For this purpose, the step-up converter 14 is designed to provide a direct voltage U _ZK at the pick-up terminals 8 e , 8 f of the direct-voltage pick-up device 8 as a function of the potential difference between the half-bridge circuits 9 and 15 . The step-up converter 14 can have, for example, a converter inductor 10 and an output diode 11 connected in series, a regulator switching element 12 coupling the midpoint tap to the second half-bridge circuit 15 . Or the converter inductor 10 can also be arranged between the second half-bridge circuit 15 and the regulator switching element 12, or two converter inductors can be arranged on the two input terminals of the boost converter 14 10. In addition, the two converter inductance coils are optionally magnetically coupled to each other, that is, they can be wound on the same iron core. The same applies to the output diode 11 , which can alternatively also be arranged between the output tap 8 f and the regulator switching element 12 .

The regulator switching element 12 can have, for example, a power semiconductor switch, such as a MOSFET switch or an IGBT switch. For example, an n-channel IGBT, which is blocked in the normal state, can be used for the regulator switching element 12 . However, it should be clear here that any other power semiconductor switch can likewise be used for the regulator switching element 12 .

It is possible to dispense with the regulator switching element 12, or to keep the regulator switching element 12 permanently off, if the potential difference between the collecting terminals of the half-bridge circuits 9 and 15 is always at This is especially true if the input voltage range given by the other components on 8e, 8f. In this case, the output diode 11 can also be dispensed with in some embodiments.

The DC voltage pick-up device 8 can additionally have an intermediate circuit capacitor 13 which is connected between the pick-up terminals 8e, 8f of the DC voltage pick-up device 8 and which is designed for this purpose to be connected to the DC voltage pick-up device 8 The current pulses output by boost converter 14 are buffered and thus generate a smoothed DC voltage U _ZK at the output of boost converter 14 . Via intermediate circuit capacitor 13 , it is then possible, for example, to supply the DC converter of the on-board system of an electric vehicle or, in certain cases, to connect the on-board system directly to intermediate circuit capacitor 13 .

The number of diodes 9 a and 15 a in half-bridge circuits 9 and 15 is, for example, three in FIG. 4 and is adapted to the number of output connections 1 a , 1 b , 1 c of energy storage device 1 . It should be clear here that, depending on which phase voltage the energy storage device 1 generates, any other number of diodes in the half-bridge circuits 9 and 15 is likewise possible.

FIG. 5 shows a schematic diagram of a system 300 with an energy storage device 1 and a DC voltage interception device 8 . The system 300 differs from the system 200 shown in FIG. 4 mainly in that the DC voltage interception device 8 additionally has a reference connection 8 d which is coupled to the reference potential busbar 4 of the energy storage device 1 . An output diode 16a or 17a is respectively connected between the aggregation terminal of the half-bridge circuits 9 and 15 and the reference terminal 8d. The cathode of the first compensation diode 16 a is coupled to the collection point of the first half-bridge circuit 9 , and the anode of the second compensation diode 17 a is coupled to the collection point of the second half-bridge circuit 15 .

Via the compensation diode 16a or 17a, the potential present at the junction of the half-bridge circuits 9 and 15 can be limited, wherein the potential falls or rises to the reference potential present at the reference terminal 8d. In this case, compensation diode 16a limits the potential at the collecting terminal of half-bridge circuit 9 downward to the reference potential, and compensating diode 17a limits the potential at the collecting terminal of half-bridge circuit 15 upward to the reference potential. In the case of low stator voltages in the phase lines 2 a , 2 b , 2 c , for example at small rotational speeds or in the standstill state of the electric machine 2 , this also ensures a sufficiently high voltage across the input terminals of the boost converter 14 . potential difference in such a way that the neutral point potential of the motor 2 is increased or decreased by a unit value. If the potential difference between the corresponding instantaneous highest potential and the corresponding instantaneous lowest potential at the output terminals 1a, 1b, 1c of the energy storage device 1 is below a predetermined threshold value, then the neutral point potential of the electric machine 2 This can be increased or decreased by identically increasing or decreasing the output voltages of several energy supply branches of the energy storage device 1 . That is, the output potentials of all energy supply branches Z are raised or lowered by a unit value without affecting the stator voltage and/or the stator current of the electric machine 2 . Here, the high compensation diode 16 a is allowed to shift the neutral point potential of the motor 2 to a smaller value, so as to increase the input voltage of the boost converter 14 . On the contrary, the compensation diode 17 a is allowed to shift the neutral point potential of the motor 2 to a larger value to increase the input voltage of the boost converter 14 . According to the invention it is thus also possible to provide only one of the two compensation diodes 16a or 17a, since it allows an increase in the input of the boost converter 14 in combination with a shift in the corresponding direction of the neutral point potential of the electric machine 2 voltage without thereby affecting the stator voltage and stator current of the motor 2. In order to compensate fluctuations caused by the commutation process, a further commutation inductance 16 b or 17 b can be connected in series with the corresponding compensation diode 16 a and 17 a, respectively.

FIG. 6 shows a schematic illustration of a method 20 for generating a DC voltage U _ZK from an energy storage device, in particular energy storage device 1 , as shown in conjunction with FIGS. 1 to 5 . The method can be used, for example, to provide a DC voltage U _ZK for an on-board electrical system of an electric vehicle with the electric drive system 200 or 300 of FIG. 4 or 5 .

In the electric drive system 200 according to FIG. 4 , in a first step S1 a correspondingly instantaneously highest potential can be tapped at the output terminals 1 a , 1 b , 1 c of the energy storage device 1 . In the electric drive system 200 according to FIG. 4 , in a second step S2 a respective instantaneous minimum potential can be tapped at the output terminals 1 a , 1 b , 1 c of the energy storage device 1 . Then, in a step S3 , the potential difference between the corresponding instantaneous highest potential and the corresponding instantaneous lowest potential can be boosted by means of a step-up converter. The potential difference boosted in step S4 can be provided as direct voltage U _ZK . In a step S5 , an intermediate circuit capacitor 13 is optionally supplied with the supplied DC voltage U _ZK . For example, as shown in FIG. 5 , if the electric drive system 300 has a compensation diode 16a, then in a first step S1 the output terminals 1a, 1b, 1c and the reference potential busbar 4 of the energy storage device 1 are connected to Intercept a corresponding instantaneous highest potential. For example, as shown in FIG. 5, if the electric drive system 300 has a compensation diode 17a, then in a second step S2, the output terminals 1a, 1b, 1c of the energy storage device 1 and the reference potential busbar 4 are connected Intercept a corresponding instantaneous lowest potential.

The method 20 can be used, for example, to operate the DC voltage interception device 8 in the electric drive system 200 or 300 .

Claims (17)

1. it is a kind of to be used for energy storage device（1）DC voltage capture device（8）, the energy storage device has multiple energy supply branch roads （Z）, the energy supply branch road is respectively with multiple energy-storage modules（3）, with the energy storage device（1）Multiple lead-out terminals（1a, 1b,1c）Upper generation alternating voltage, the DC voltage capture device has：

First half-bridge circuit（9）, first half-bridge circuit have it is multiple first aggregation terminals（8a,8b,8c）, first aggregation Terminal respectively with the energy storage device（1）Lead-out terminal（1a,1b,1c）One of be coupled；

Second half-bridge circuit（15）, second half-bridge circuit have it is multiple second aggregation terminals（8g,8h,8i）, described second gathers Collection terminal respectively with the energy storage device（1）Lead-out terminal（1a,1b,1c）One of be coupled；And

Boost converter（14）, the boost converter is coupling in first half-bridge circuit（9）With second half-bridge circuit（15）It Between, and the boost converter is designed to basis for this in first half-bridge circuit（9）With second half-bridge circuit（15）It Between potential difference and in the DC voltage capture device（8）Intercepting terminal（8e,8f）Upper offer DC voltage（U_ZK）.

2. DC voltage capture device according to claim 1（8）, wherein first half-bridge circuit（9）With multiple One diode（9a）, first diode is respectively coupled in the boost converter（14）With the multiple first aggregation terminals（8a, 8b,8c）One of between.

3. DC voltage capture device according to claim 2（8）, wherein first half-bridge circuit（9）With multiple One commutating inductance coil（9b）, the first commutating inductance coil is respectively coupled in multiple first diodes（9a）Turn with the boosting Parallel operation（14）Between.

4. the DC voltage capture device according to claim 2 and one of 3（8）, wherein second half-bridge circuit（15）Tool There are multiple second diodes（15a）, second diode is respectively coupled in the boost converter（14）With the multiple first aggregations Terminal（8g,8h,8i）One of between.

5. DC voltage capture device according to claim 4（8）, wherein second half-bridge circuit（15）With multiple Two commutating inductance coils（15b）, the second commutating inductance coil is respectively coupled in multiple second diodes（15a）With the boosting Converter（14）Between.

6. DC voltage capture device according to claim 4（8）, wherein the plurality of first diode（9a）Anode Respectively with the described first aggregation terminal（8a,8b,8c）It is coupled, and the plurality of second diode（15a）Negative electrode difference With the described second aggregation terminal（8g,8h,8i）It is coupled.

7. the DC voltage capture device according to one of claims 1 to 3（8）, the wherein boost converter（14）Have Converter inductance coil（10）, output diode（11）And regulation switch element（12）.

8. DC voltage capture device according to claim 7（8）, the wherein regulation switch element（12）With power half Conductor is switched.

9. the DC voltage capture device according to one of claims 1 to 3（8）, also have in addition：

Intermediate loop electric capacity（13）, the intermediate loop Capacitance Coupled is in the DC voltage capture device（8）Intercepting terminal（8e, 8f）Between, and the intermediate loop electric capacity is designed to for this：It is fed by the boost converter（14）The electric current arteries and veins for being generated Punching, and by it in the boost converter（14）Output end on change into smooth DC voltage（U_ZK）.

10. the DC voltage capture device according to one of claims 1 to 3（8）, also have in addition：

First compensation diode（16a）, its anode and the energy storage device（1）Reference potential bus-bar（4）It is coupled, and its Negative electrode and the boost converter（14）First input end be coupled；And/or

Second compensation diode（17a）, its negative electrode and the energy storage device（1）Reference potential bus-bar（4）It is coupled, and its Anode and the boost converter（14）The second input terminal be coupled.

A kind of 11. power drive systems（200；300）, it has：

Energy storage device（1）, the energy storage device（1）Branch road is supplied with multiple energy（Z）, the energy supplies branch road to be had respectively Multiple energy-storage modules（3）, with the energy storage device（1）Multiple lead-out terminals（1a,1b,1c）On generating alternating voltage；With And

DC voltage capture device according to one of claim 1 to 10（8）, the first of the DC voltage capture device gathers Collection terminal（8a,8b,8c）With the second aggregation terminal（8g,8h,8i）Respectively with the energy storage device（1）Lead-out terminal（1a,1b, 1c）One of be coupled.

12. power drive systems according to claim 11（200；300）, also have in addition：

N phase motors with n phase terminal（2）, the motor and the energy storage device（1）Lead-out terminal（1a,1b,1c）Phase coupling Close, wherein n >=1.

13. is a kind of for from energy storage device（1）Middle generation DC voltage（U_ZK）Method（20）, the wherein energy storage device has many Individual energy supplies branch road（Z）, the energy supply branch road is respectively with multiple energy-storage modules（3）, with the energy storage device（1）'s Multiple lead-out terminals（1a,1b,1c）Upper generation alternating voltage, the method has below step：

In the energy storage device（1）Multiple lead-out terminals（1a,1b,1c）Upper intercepting（S1）Corresponding instantaneous highest current potential；

In the energy storage device（1）Multiple lead-out terminals（1a,1b,1c）Upper intercepting（S2）Corresponding instantaneous potential minimum；

Potential difference between corresponding instantaneous maximum potential and corresponding instantaneous potential minimum is utilized boost converter（14）To rise Pressure（S3）；And

There is provided（S4）The DC voltage relevant with the potential difference of boosting（U_ZK）.

14. methods according to claim 13（20）, have steps of：

Intercept（S1）In the energy storage device（1）Multiple lead-out terminals（1a、1b、1c）Above and with reference to potential bus-bar（4） On corresponding instantaneous maximum potential.

15. methods according to claim 13 or 14（20）, have steps of：

Intercept（S2）In the energy storage device（1）Multiple lead-out terminals（1a、1b、1c）Above and with reference to potential bus-bar（4） On corresponding instantaneous potential minimum.

16. methods according to claim 13 or 14（20）, also have steps of in addition：

The DC voltage for being provided（U_ZK）Feeding（S5）Give intermediate loop electric capacity（13）.

17. methods according to claim 16（20）, the method is for using electric drive according to claim 11 System（200；300）The DC voltage is provided for electrical network on the car of electric automobile（U_ZK）.