WO2012163572A2

WO2012163572A2 - Power supply device for inverter circuits

Info

Publication number: WO2012163572A2
Application number: PCT/EP2012/055945
Authority: WO
Inventors: Peter Feuerstack; Erik Weissenborn; Martin Kessler
Original assignee: Robert Bosch Gmbh
Priority date: 2011-05-27
Filing date: 2012-04-02
Publication date: 2012-12-06
Also published as: DE102011076571A1; WO2012163572A3

Abstract

The invention relates to a system having a power supply device that is designed to provide an operating a.c. voltage, and an energy storage device for generating a n-phase supply voltage for an electric motor, wherein n ≥ 1, comprising n parallel-connected power supply branches respectively connected to one of n phase terminals, wherein each of the power supply branches has a plurality of series-connected energy storage modules (3) that each comprise an energy storage cell module (5) having at least one energy storage cell (5a, 5n), a coupling device (9) having coupling elements (7, 8) designed to switch the energy storage cell module (5) selectively into the respective power supply branch or to bypass same, a transformer (13) that converts the operating a.c. voltage of the power supply device into a module a.c. voltage, a rectifier circuit (14) that rectifies the module a.c. voltage into a module d.c. voltage, and a module supply device (15) that is operated by means of the module d.c. voltage and is designed to supply power to the coupling elements (7, 8) of the coupling devices (9).

Description

Description title

Power supply device for inverter circuits

The invention relates to a power supply device for inverter circuits and a system having a power supply device for a

Energy storage device with inverter functionality, in particular in a battery direct converter circuit for powering electrical machines.

PRIOR ART It is clear that in the future, both in stationary applications, such. B.

Wind turbines or solar systems, as well as in vehicles such as hybrid or

Electric vehicles, increasingly electronic systems are used, which combine new energy storage technologies with electric drive technology. 1, for example, shows the feeding of three-phase current into a three-phase electrical machine 101. In this case, a DC voltage provided by a DC voltage intermediate circuit 103 is converted into a three-phase AC voltage via a converter in the form of a pulse-controlled inverter 102. The DC intermediate circuit 103 is fed by a string 104 of serially connected battery modules 105. In order to meet the power and energy requirements of a particular application, multiple battery modules 105 are often connected in series in a traction battery 104.

The series connection of several battery modules involves the problem that the entire string fails if a single battery module fails. Such a failure of the power supply string can lead to a failure of the entire system. Furthermore, temporarily or permanently occurring power reductions of a single battery module can lead to power reductions in the entire power supply line. In the document US 5,642,275 A1 a battery system with integrated

Inverter function described. Systems of this type are known under the name Multilevel Cascaded Inverter or Battery Direct Inverter (Battery Direct Inverter, BDI). Such systems include DC sources in multiple Energy storage module strings, which are directly connectable to an electrical machine or an electrical network. This can be single-phase or multi-phase

Supply voltages are generated. The energy storage module strands in this case have a plurality of energy storage modules connected in series, wherein each energy storage module has at least one battery cell and an associated controllable coupling unit, which makes it possible to interrupt the respective energy storage module string depending on control signals or to bridge the respectively associated at least one battery cell or each associated with at least one battery cell in the respective energy storage module string to switch. By suitable activation of the coupling units, e.g. With the aid of pulse width modulation, suitable phase signals for controlling the phase output voltage can also be provided so that a separate pulse inverter can be dispensed with. The required for controlling the phase output voltage pulse inverter is thus integrated so to speak in the BDI.

BDIs usually have higher efficiency and higher

Resiliency over conventional systems, as shown in Fig. 1, on. The reliability is ensured, inter alia, that defective, failed or not fully efficient battery cells can be switched out by suitable bridging control of the coupling units from the power supply lines.

The energy for the control of the coupling units is usually by the

Battery cells provided within the energy storage module itself. at

de-energized battery cells, for example in the case of defective or completely discharged battery cells, may therefore be the case in which the coupling units can no longer be actuated due to a lack of operating voltage. In these cases, a suitable bridging control of the coupling units is no longer possible and the entire power supply line fails.

Disclosure of the invention

The present invention provides, according to one embodiment, a system having a power supply device which is adapted to a

To provide operating AC voltage, and an energy storage device for

Generating an n-phase supply voltage for an electrical machine, wherein n> 1, with n parallel-connected power supply branches, which are each connected to one of n phase terminals, each of the power supply branches a A plurality of series connected energy storage modules, each comprising:

an energy storage cell module having at least one energy storage cell, a coupling device with coupling elements, which are designed to, the

Energy storage cell module selectively in the respective power supply branch to switch or bypass, a transformer that converts the AC operating voltage of the power supply device into a module AC voltage, a

Rectifier circuit which rectifies the module AC voltage into a DC module voltage, and a module supply means which is operated with the module DC voltage, and which is adapted to supply the coupling elements of the coupling means with energy.

ADVANTAGES OF THE INVENTION One idea of the present invention is to reduce the reliability of

Battery direct converters still increase by an external

Power supply device for the coupling devices of energy storage modules of an energy storage device is provided. The power supply device provides an operating AC voltage for each of the energy storage modules that can be internally converted into a DC module voltage in each of the energy storage modules. The module DC voltage then serves to supply the active power

Switching elements of the coupling devices. As a result, the coupling devices of a power supply through the associated energy storage cells are self-sufficient, so that the coupling devices can be controlled even in case of a defect or a complete discharge of the energy storage cells to a safe switching state, for example, a bridging state of the defective or discharged

To ensure energy storage cells. Thus, the energy storage device can be operated in any case even in the event of failure of individual energy storage cell modules.

Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings.

Brief description of the drawings

Show it: 1 is a schematic representation of a power supply system for a three-phase electrical machine,

Fig. 2 is a schematic representation of a system with a

Energy storage device and a power supply device according to an embodiment of the present invention,

3 shows a schematic representation of the structure of an energy storage module of an energy storage device according to a further embodiment of the present invention, and

4 is a schematic representation of the structure of an energy storage module of an energy storage device according to still another

Embodiment of the present invention.

2 shows a system 20 for voltage conversion of DC voltage provided by energy storage modules 3 into an n-phase AC voltage. The system 20 includes an energy storage device 1 with energy storage modules 3, which are connected in series in power supply branches. By way of example, three energy supply branches are shown in FIG. 2, which are used to generate a three-phase

AC voltage, for example, for a three-phase machine 2, are suitable.

In principle, however, any other number of phases is equally possible. The

Energy storage device 1 has at each power supply branch via an output terminal, which are respectively connected to phase lines 2a, 2b, 2c. By way of example, the system 20 in FIG. 2 serves for feeding an electric machine 2, in particular as a traction battery for the electric drive of an electrically operated vehicle, such as an electric vehicle or a hybrid vehicle.

The system 20 may further comprise 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 the desired

Output voltages to provide the respective phase terminals 2a, 2b, 2c.

The power supply branches can be connected at their end to a reference potential 4 (reference rail) which, in the illustrated embodiment, has an average potential with respect to the phase lines 2a, 2b, 2c of the electric machine 2. The reference potential 4 may be, for example, a ground potential. Each of the power supply branches has at least two in series Energy storage modules 3 on. By way of example, the number of energy storage modules 3 per power branch in FIG. 2 is three, but any other number of energy storage modules 3 is also possible. In this case, each of the energy supply branches preferably comprises the same number of energy storage modules 3, but it is also possible to provide a different number of energy storage modules 3 for each energy supply branch.

The energy storage modules 3 each have two output terminals 3a and 3b, via which an output voltage of the energy storage modules 3 can be provided.

The system 20 further comprises a power supply device 1 1, which is designed to provide an AC operating voltage. The

Power supply device 1 1, for example, from a (not shown) DC voltage source using a chopper or Multivibratorschaltung a

Generate AC voltage via leads 1 1 a and 1 1 b to the

Energy storage device 1 can be issued. The

Power supply device 1 1 can be arranged for example in the energy storage device 1 itself. It may also be that the energy supply device 1 1 in the control device 6 or an external control system, such as a battery management system, is arranged.

About the leads 1 1 a and 1 1 b, the AC operating voltage of the

Power supply device 1 1 to the individual energy storage modules. 3

issued. For reasons of clarity, only the energy storage modules 3 of a power supply branch are shown to be supplied with the operating AC voltage. However, it is understood that the other energy storage modules 3 of the other energy supply branches can be supplied in a similar manner with the AC operating voltage. It can be provided that between the

Energy storage modules 3 lines 12 are provided, which allow a series connection of the energy storage modules with respect to the operating AC power supply. Similarly, the energy storage modules 3 can each

Energieversorgungszweigs be supplied in parallel with the AC operating voltage.

An exemplary construction of the energy storage modules 3 is shown in greater detail in FIG. The energy storage modules 3 each comprise a coupling device 9 with a plurality of coupling elements 7 and 8. The energy storage modules 3 further comprise in each case one energy storage cell module 5 with one or more energy storage cells 5a, 5n connected in series.

The energy storage cell module 5 can have, for example, serially connected batteries 5a, 5n, for example, lithium-ion batteries. In this case, the number of energy storage cells 5a, 5n in the energy storage module shown in FIG. 2 is exemplary two, but any other number of energy storage cells 5a, 5n is also possible. The energy storage cell modules 5 are connected via connecting lines

Input terminals of the associated coupling device 9 connected. The

Coupling device 9 is shown in Fig. 3 by way of example as a full bridge circuit with two each

Coupling elements 7 and two coupling elements 8 is formed. The coupling elements 7 and 8 can each have an active switching element, for example, a semiconductor switch, and a freewheeling diode connected in parallel thereto. The semiconductor switches may comprise field effect transistors (FETs), for example. In this case, the freewheeling diodes can also be integrated in each case in the semiconductor switches. In the illustrated embodiments, the active switching elements or the coupling elements 7 and 8 as a power semiconductor switch, for example in the form of IGBTs (Insulated Gate Bipolar Transistors), JFETs (junction field-effect transistor) or as MOSFETs (Metal Oxide Semiconductor Field-Effect Transistors ).

The coupling elements 7 and 8 in Fig. 3 can be controlled in such a way, for example by means of the control device 6 in Fig. 2, that the energy storage cell module 5 is selectively connected between the output terminals 3a and 3b or that

Energy storage cell module 5 is bridged. By suitable driving the

Coupling devices 9, therefore, individual energy storage cell modules 5 of the energy storage modules 3 can be specifically integrated into the series connection of a power supply branch.

The active switching elements receive their operating voltage from a

Module supply device 15, which is arranged in each energy storage module 3. To provide the operating voltage for the coupling device 9 is in the

Energy storage module 3, a transformer 13 is arranged, whose primary winding 13a is connected to the leads 1 1 a and 1 1 b and 12 respectively. About the leads 1 1 a and 1 1 b and 12 is provided by the power supply device 1 1

Operating AC voltage fed to the energy storage module 3. At the

Secondary winding 13b of the transformer 13 can be tapped off a module AC voltage which is output via lines 14a and 14b to a rectifier circuit 14. The rectifier circuit 14 rectifies the module AC voltage

Module DC voltage around. The module DC voltage is delivered via lines 15a and 15b to the module supply device 15. The module supply device 15 can furthermore have a voltage stabilization circuit (not shown), for example with an intermediate circuit capacitor for stabilizing the module direct voltage.

4 shows a further exemplary embodiment of an energy storage module 3. The energy storage module 3 shown in FIG. 4 differs from the energy storage module 3 shown in FIG. 3 in that the coupling device 9 has two instead of four coupling elements 7, 8, which take place in a half-bridge circuit are interconnected in full bridge circuit. Furthermore, the energy storage module 3 shown in FIG. 4 differs from the energy storage module 3 shown in FIG. 3 in that a center tap 14c is provided on the secondary side 13b of the transformer 13, via which, for example, further secondary voltages such as, for example, a secondary voltage of opposite polarity are tapped can. Of course, it is also possible that the secondary side 13b of the transformer 13 shown in FIG. 3 has a similar center tap 13c or that the secondary side 13b of the transformer 13 does not have the center tap 13c. Furthermore, it may be possible to arrange on the secondary side 13b of the transformer 13 two separate secondary windings 13b, on each of which two different module alternating voltages for powering the coupling devices 9 can be tapped.

Claims

Claims 1. System (20), with:

a power supply device (1 1), which is designed to a

Provide operating AC voltage; and

an energy storage device (1) for generating an n-phase

Supply voltage for an electrical machine (2), where n> 1, with:

n parallel power supply branches, each with one of n

Phase terminals (2a, 2b, 2c) are connected, wherein each of the

Power supply branches a variety of series-connected

Energy storage modules (3), each comprising:

an energy storage cell module (5), which at least one

Energy storage cell (5a, 5n) comprises;

a coupling device (9) with coupling elements (7, 8), which are designed to selectively the energy storage cell module (5) in the respective

Switching or bridging the power supply branch;

a transformer (13), the operating AC voltage of the

Energy supply device (1 1) converts into a module AC voltage; a rectifier circuit (14), the module AC voltage in a

Modulgleichspannung rectifies; and

a module supply device (15), which is operated with the modulo dc voltage, and which is adapted to the coupling elements (7, 8) of the

To supply coupling devices (9) with energy.

2. System (20) according to claim 1, wherein the energy storage modules (3) further comprise a DC voltage intermediate circuit for stabilizing the module DC voltage.

3. System (20) according to any one of claims 1 and 2, wherein the coupling means (9) comprise coupling elements (7, 8) in full-bridge circuit.

4. System (20) according to any one of claims 1 and 2, wherein the coupling means (9) comprise coupling elements (7,8) in half-bridge circuit.

The system (20) of any one of the preceding claims, further comprising: an n-phase electric machine (2), wherein n> 1, whose phase lines are connected to the phase terminals (2a, 2b, 2c) of the energy storage device (1); and

a control device (6) which is designed to selectively control the coupling devices (9) of the energy storage modules (3) for generating a supply voltage for the electrical machine (2).