DE102010051323B4 - Charging system for charging a battery of a vehicle with a two-way charge controller - Google Patents

Abstract

A charging system (1) for charging a battery (6) of a vehicle, the charging system (1) comprising: at least one converter for converting an AC voltage to a DC voltage during charging of the battery (6) and for converting a DC voltage into an AC voltage when operating a Electric motor (3) through the battery (6), a power supply charging connection (10) for connecting an external power supply network to the inverter, an intermediate circuit capacitor (4), and at least one first switching unit (11a, 11b) for separating an electrically conductive connection between the inverter and the electric motor (3), characterized by a two-way charge controller (5) connected directly and by means of a third switching unit (22) interruptible to the battery (6) for charging an input voltage from the external power supply network during the charging process the battery (6) and for charging-boosting an input voltage from the battery (6) for charging the zwi the two-way charge controller (5) and the inverter (2, 2a, 2b), parallel-connected capacitor (4), wherein the two-way charge controller (5) one of an operating circuit for operating the electric motor (3) the battery (6) independent charging circuit with the battery (6) for charging the battery (6) and the capacitor (4), wherein the charging circuit comprises a first positive conductor (12a, 12b) and a negative conductor (13).

Description

The present invention relates to a charging system for charging a battery of a vehicle according to the preamble of claim 1.

Due to the progressive development with respect to the drives of a vehicle, electric motors are increasingly being used, either in hybrid drives, in that one or more electric motors are drivingly coupled to an internal combustion engine, or as sole drive motors for driving a purely electrically operated vehicle, such as a passenger car Mopeds or mopeds or even a bicycle.

Electric motors, which are preferably used in hybrid drives together or in addition to the internal combustion engines, are usually connected to a battery or an accumulator, which z. B. are supplied by the brake power recovery and during operation of the internal combustion engine with electrical energy to charge accordingly. Consequently, it is not necessary this battery, for example, via an external power supply network, for. B. while the vehicle is parked, in addition to charge.

The situation is different with purely electrically operated vehicles, in which only one or more electric motors take over the drive of the vehicle. It is understandable that here too the battery supplying the electric motor with electrical current can also be supplied with electrical energy by, for example, the brake force recovery, but this energy recovery is not sufficient, for example, to move a passenger car over a longer distance. In addition, additional energy converters, such as the internal combustion engine in the hybrid drives omitted. Consequently, it is necessary to additionally charge the battery of this electric vehicle by means of, for example, external power grids.

The arranged in the vehicle charging system has for this purpose in addition to the battery and the electric motor to internal knowledge usually a converter for converting a DC voltage into an AC voltage when operating the electric motor and for converting an AC voltage into a DC voltage when charging the battery, a power grid charging port for connecting of the external power supply network and a voltage adjustment module for adapted charging of the battery according to the charging characteristic of the battery.

In most cases, especially the voltage adjustment module, which is used for example during charging of the battery, or its components are so highly dimensioned that both the useful power of the electric motor, which may be about 100 KW, for example, is performed on the voltage adjustment module, as well the network power of the external power supply network for charging the battery.

DE 10 2008 063 465 A1 shows a system with a battery, an inverter, an electric motor, a switching device and a power supply and a charge controller. Furthermore, the device comprises a link capacitor, which is arranged on the side of the battery. The charge controller is disposed between the inverter and the battery and may be configured as a buck converter or as a boost converter. If the switching device is connected such that the motor has a connection to the battery, then the motor can be operated by means of the battery. If the switching device is connected in such a way that the battery is connected to the mains connection, then the battery can be charged.

US 2004/0062059 A1 describes a converter, which is connected via a switching unit with a charge controller. About the switching unit, the inverter can be connected to a power supply network, for example, to charge the battery via the charge controller. In a circuit of the switching unit, for example when charging the battery, and a corresponding switching of the switching unit, an electric motor can be connected to the inverter and the memory devices such that this electric motor can be operated via with drawn from the memory devices electrical power.

Accordingly, it is the object of the present invention to provide a charging system for charging a battery of a vehicle having a two-way charge controller, which uses only small, needs-sized components due to its circuit arrangement, whereby the charging system is inexpensive and space to produce optimized , and which also has a reduced number of power semiconductors used in the construction of the charging system, thus simplifying the manufacture of the charging system.

This object is achieved by the present invention by means of a charging system for charging a battery of a vehicle according to claim 1.

Accordingly, a charging system for charging a battery of a vehicle is claimed, wherein the charging system has at least one converter for converting an AC voltage into a DC voltage during charging of the battery and the Converting a DC voltage into an AC voltage when operating an electric motor by the battery, a power supply charging connection for connecting an external power supply network to the inverter, a DC link capacitor, and at least one first switching unit for separating an electrically conductive connection between the inverter and the electric motor.

In this case, the charging system according to the invention is characterized by a directly and by means of a third switching unit interruptible connected to the battery two-way charge controller for charge-subsetting an input voltage from the external power supply network during the charging of the battery and charge-boosting an input voltage from the battery Charge the capacitor connected in parallel between the two-way charge controller and the inverter. In addition, the two-way charge controller has a charging circuit independent of an operating circuit for operating the electric motor by the battery with the battery for charging the battery and the capacitor, wherein the charging circuit comprises a first positive conductor and a negative conductor.

As a result, it is possible for the battery, for example via the charging circuit and in particular via the plus conductor, to conduct an electric current to the two-way charge controller, so that the latter, preferably in the form of a boost converter, converts the input voltage generated by the battery into a higher one Output voltage converts to charge the capacitor or the DC link capacitor.

The charging of the capacitor to a maximum voltage or to a voltage which is higher than the voltage of the external power supply network is especially important before plugging in the power supply socket to an external power grid to avoid inrush surges and consequently the battery, as well to protect the external power supply itself from damage.

For example, the capacitor in an intermediate circuit, which also has the parallel to the capacitor connected two-way charge controller and the battery connected in parallel, arranged.

When the capacitor is charged, the two-way charge controller or the electrical components provided for this purpose are dimensioned, for example, to approximately 50 W only.

A second mode of operation of the two-way charge controller is the charge of the battery or the vehicle battery, in this case, the two-way charge controller acts as a buck converter or down converter to the battery by means of a network performance of the external power supply network, the usual characteristics , such as B. 220 to 240 V (single-phase AC) or about 400 V (three-phase network) has to load.

For this purpose, the two-way charge controller or the electrical components provided for this purpose are dimensioned, for example, at about 3 to 100 kW, preferably at about 5 to 50 kW and particularly preferably at about 10 to 25 kW, in order to charge the battery quickly without damaging, overcharging or fully charging the battery.

A monitoring and in particular a control and regulation of the charging and discharging currents to and from the battery is effected, for example, by means of a charging control element, which is preferably a component of the two-way charge controller, which by overcharging and monitoring of the charging characteristics of the battery / or incomplete charging of the battery prevented.

Consequently, the two-way charge controller is also able to detect the charging characteristics of the battery to allow a tuned charging the battery, for example by adjusting the charging current or the charging voltage.

Consequently, the two-way charge controller is dimensioned to a necessary charging power and therefore does not have to be designed for a maximum traction power, whereby additional components are saved in contrast to the conventional charging systems.

It should also be noted that in order to allow a charging of the battery, the line between the electric motor and the at least one inverter should be separated by means of, for example, the first switching unit, which consists of at least one electrical switch. This prevents that the electric motor electrical energy of the external power supply network is supplied, which could be driven. An additional locking of the vehicle during the charging of the battery is therefore not required.

The two-way charge controller itself is connected in a circuit independent of the operating circuit. That is, the operating circuit used for operating the electric motor by the battery, and thus comprising at least the battery, the electric motor and the inverter, regardless of the charging circuit, which is used for charging the battery and the capacitor and at least the Battery, the two Off-charge controller and the capacitor and / or the inverter comprises, is switched.

Thus, an electric current flow controlled by the two-way charge regulator flows only through the charging circuit, which has for this purpose a first positive conductor which is connected to the positive pole of the battery and a negative conductor which is connected to the negative pole of the battery.

In a preferred embodiment, the negative conductor of the charging circuit corresponds to the negative conductor of the operating circuit.

Accordingly, the operating circuit has a second positive conductor and a negative conductor common to the charging circuit, wherein the operating circuit is interruptible by means of a second switching unit connected to the second positive conductor.

However, it is also conceivable that the charging circuit has a negative conductor independent of the operating circuit, which runs from the negative pole of the battery, via the two-way charge controller to, for example, the intermediate circuit capacitor.

The operating circuit may preferably be interrupted by means of the second switching unit to allow charging of the capacitor or the battery by means of the charging circuit.

If the second switching unit, which preferably consists of an electrical switch, is activated in such a way that an electric current can flow through the operating circuit (switch on), a bridging of this charging circuit takes place when the charging circuit is still switched on, whereby the battery is discharged via the operating circuit and consequently comes to the operation or drive of the electric motor. Consequently, this second switching unit serves as galvanic isolation of the battery from the electric motor.

The charging circuit can also be separated from the battery during the drive of the electric motor by the battery, for example by means of a third switching unit (switch of the third switching unit is open).

In a preferred embodiment, the first positive conductor of the charging circuit has a first line section from the capacitor to the two-way charge controller and a second line section from the two-way charge controller to a positive pole of the battery, wherein the second switching unit between the charging circuit and the positive pole of the Battery is switched.

As a result, the charging circuit "bypasses" the second switching unit and thus can not be interrupted by it.

Further, for example, the inverter and preferably the DC side of the inverter with the positive conductor or with the first line section of the positive conductor is connected.

It is also conceivable that, based on the arrangement of the first positive conductor of the two-way charge controller is connected to a separate from the operating circuit second negative conductor to the negative terminal of the battery. As a result, for example, this second negative conductor of the charging circuit would have a first line section from a negative terminal of the battery to the two-way charge controller and a second line section from the two-way charge controller to the condenser.

In a preferred embodiment, for example, the inverter and preferably the DC side of the inverter is connected to the negative conductor.

As a result, the two-way charge controller is preferably connected in parallel with the battery and / or preferably in parallel with the capacitor and / or with the converter.

In a further preferred embodiment, the two-way charge controller has at least two power switches as electronic components, each power switch each comprising a transistor in parallel with a diode.

This makes it possible, for example, to conduct a rectified electric current coming from the battery via a power switch to the capacitor in order to charge the latter.

On the other hand, it is possible to transport an electric current rectified by the inverter and the capacitor via a power switch to the battery, thus charging the battery.

The two-way charge controller preferably has at least one charge control element for charging power control of the battery, which is preferably connected at least to the circuit breakers of the two-way charge controller and / or to the third switching unit of the two-way charge controller.

It is also conceivable that the charging control element with, for example, a Vorladekreislauf, which preferably consists of a resistor and a switching unit is connected, said pre-charge preferably represents a part of the two-way charge controller and is used for example during charging or before charging the DC link capacitor to damage the DC link capacitor by too large To prevent surges from the battery.

By means of the charging control element, it is possible, for example, to determine the required charging power of the battery, for. B. to generate a defined voltage in the charge of the battery. This is necessary due to the fact that the battery itself, which z. B. for the drive of the electric motor about 100 kW can provide power, but even for example with about 3 to 100 kW, preferably with about 5 to 50 kW and more preferably with about 10 to 25 kW from the external power grid is loadable.

It should also be noted that the capacitor is not only used as a smoothing capacitor in the conversion of the alternating current into direct current, but is also used for temporary storage of electrical energy to avoid, for example inrush surges when plugging the power grid charging connection to the external power grid.

For this, the capacitor is charged by means of electrical energy of the battery, which is transported by the two-way charge controller, so that ultimately the capacitor or the intermediate circuit has a higher voltage than the voltage of the external power supply network.

In a further preferred embodiment, the inverter comprises at least two power switches per phase, each comprising a transistor in parallel with a diode, the two power switches being connected in series, and the power grid charging terminal being connected at a node between the two power switches ,

Accordingly, the power grid charging terminal is preferably located on the AC side of the inverter to supply electrical power received from the external power grid to an inverter.

Furthermore, the converter preferably comprises three series circuits connected in parallel to each other, each comprising at least two power switches, wherein the series circuits are each connected in parallel to the capacitor.

In a further preferred embodiment, the inverter is a double converter, which has a first and a second converter or inverter for converting the DC voltage of the battery into an AC voltage for the electric motor when operating the electric motor or an AC voltage of the external power supply network in a DC voltage for the battery during the charging of the battery, wherein the electric motor is connected to each of the first and the second inverter.

In a further preferred embodiment, the first switching unit, for example, two switches or switching units, which are each connected between the first and the second inverter, so that these switching units can each separate a connection between the two converters.

It is also conceivable that the electric motor is a three-phase motor connected in a star connection, which is consequently connected between the two inverters or inverters of the double converter.

In addition, it is possible that the two-way charge controller is part of the battery and therefore not a separate electrical component.

Further advantages, objects and characteristics of the present invention are explained with reference to the following description of the appended drawing, in which two circuits of embodiments of the charging system according to the invention are shown by way of example.

Components which at least substantially coincide in the figures with respect to their function may in this case be identified by the same reference symbols, these components not having to be identified and explained in all figures.

In the figures show:

1 a circuit of a first embodiment of the charging system according to the invention with a double converter, and

2 a detail of a circuit of a second embodiment of the charging system according to the invention.

In the 1 is a circuit of a first embodiment of the charging system according to the invention 1 with a double inverter 2 , which consists of a first inverter 2a or first inverter 2a and a second inverter 2 B or second inverter 2 B consists of an electric motor 3 , a DC link capacitor 4 or capacitor 4 , a two-way charge controller 5 and a battery 6 shown.

The two inverters 2a and 2 B each have three series circuits arranged parallel to one another, which each consist of two series-connected circuit breakers 7 put together, on. Each circuit breaker consists of a diode 8th which is parallel to a transistor 9 is switched.

The electric motor 3 is connected between the series-connected circuit breakers and therefore with both inverters 2a and 2 B connected. The capacitor 4 is parallel to the inverters 2a and 2 B as well as to the two-way charge controller 5 and the battery 6 switched.

The power grid charging port 10 is at a node between each of the two series-connected circuit breakers 7 of the first inverter 2a and the engine 3 connected. Before charging, the first switching unit, which according to 1 from two switching units or switches 11a and 11b consists, so switched, that an electrically conductive connection between the engine 3 and the power grid charging port 10 or the first inverter 2a interrupted or disconnected (switch open). This positioning of the first switching unit 11a . 11b It will also last throughout the charging process, so while charging the battery 6 by means of electrical energy from an external power supply network (not shown here) no electrical power to the engine 3 can flow. This will increase the risk of the engine 3 is driven during the charging process and the vehicle is set in motion, avoided.

The two-way charge controller 5 is via a charging circuit which a positive conductor 12a . 12b and a negative conductor 13 has with the battery 6 and the DC link capacitor 4 connected. The positive conductor 12a . 12b consists of a first wiring harness or - section 12a which at least the capacitor 4 with the two-way charge controller 5 connects and a second line section 12b which is the two-way charge controller 5 with the positive pole 6a the battery 6 connects, together. The negative conductor 13 corresponds to the 1 the negative conductor of the operating circuit.

The charging circuit is preferably used for either the capacitor 4 by means of the electrical energy of the battery 6 charge or the battery 6 to be charged by means of the electrical energy of the external power supply network.

In contrast, an independent of the charging circuit operating circuit with a second positive conductor 14 , which at the positive pole 6a the battery 6 connected and the negative conductor 13 , which at the negative pole 6b the battery 6 is connected from the battery 6 out. In addition, the operating circuit has one on the positive conductor 14 switched second switching unit 15 which, for example, causes an interruption of the operating circuit when z. B. the capacitor 4 or the battery 6 is charged or should be.

Is the switch 15 or the second switching unit 15 closed and thus allows an electrically conductive operating circuit, so there is a discharge of the battery 6 to drive the electric motor 3 , As a result, only power is passed through the operating circuit when the electric motor 3 to be supplied with electrical energy.

With this operating circuit are according to the 1 the battery 6 , the inverter 2a . 2 B or the double inverter 2 and the electric motor 3 connected.

It is conceivable that the two-way charging port 5 a component of the battery 6 is.

2 shows a section of a circuit of a second embodiment of the charging system according to the invention 1 , Here is only one inverter 2a However, it shows the same construction as the inverter 2a of the 1 and accordingly should not be explained further here. Also the DC link capacitor 4 is again parallel to the two-way charge controller 5 and to the battery 6 switched.

The two-way charge controller 5 also has two circuit breakers 7 each with a parallel to a transistor 9 switched diode 8th on. In addition, there is between the two circuit breakers 7 of the two-way charge controller 5 a precharge circuit, which consists of a resistor 23 and one to the resistance 23 connected in parallel fourth switching unit 24 exists, switched.

The further is an inductance 21 or coil 21 with a third switching unit 22 in series with the positive pole 6a the battery 6 switched. As a result, it is possible for example, a charging of the DC link capacitor 4 through the battery 6 the second switching unit 15 which according to 2 from two switching units 15a and 15b or two switches 15a and 15b consists of disable or the switches 15a and 15b open, so that no more electrical current can flow through the operating circuit, the third switching unit 22 is activated or closed. This allows an electrical current through the positive conductor of the charging circuit to the coil 21 , which in this case as a magnetic latch when charging the capacitor 4 serves, and continue to flow to the precharge circuit.

Is the fourth switching unit 24 deactivated, ie opened, the precharging of the capacitor takes place 4 about the resistance 23 to damage the capacitor 4 due to, for example, power surges.

If the capacitor voltage reaches predetermined values or the values of the battery voltage, the fourth switching unit becomes 24 preferably activated or closed, whereby the electric current freely via the corresponding circuit breaker 7 to the condenser 4 can flow, so that it is possible to increase the capacitor voltage such that it ultimately exceeds the battery voltage. This corresponds to the operation of a boost converter or a boost converter.

The charge control element 20 is on the circuit breakers 7 of the two-way charge controller 5 as well as at the third 22 and fourth switching unit 24 connected and controls or regulates, preferably the charging of the battery 6 so that it can not be overcharged, for example, or the charge of the battery is not prematurely terminated, although this is not fully charged.

It is also possible that the charge control element 20 also the charging of the DC link capacitor 4 controls and regulates, so that the capacitor voltage can be increased above the value of the battery voltage without damaging the capacitor during the charging process.

Thus, it is up to the charge control element 20 the circuit breaker 7 to control the two-way charge controller respectively according to their function to be performed to either charge the capacitor through the battery or the battery through an external power supply network.

It should be noted that the third switching unit 22 preferably a component of the two-way charge controller 5 and not part of the battery 6 is.

The Applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided that they are novel individually or in combination with respect to the prior art.

LIST OF REFERENCE NUMBERS

1

charging system

2

dual inverters

2a

first inverter

2 B

second inverter

3

electric motor

4

Link capacitor

5

Two-way charge controller

6

battery

6a

Positive pole of the battery

6b

Negative pole of the battery

7

breakers

8th

diode

9

transistor

10

Mains charging port

11a

first switch of the first switching unit

11b

second switch of the first switching unit

12a

first line section of the first positive conductor

12b

second line section of the first positive conductor

13

negative conductor

14

second positive conductor

15

second switching unit

15a

first switch of the second switching unit

15b

second switch of the second switching unit

20

Charging control element

21

inductance

22

third switching unit

23

resistance

24

fourth switching unit

Claims (12)

Charging system ( 1 ) for charging a battery ( 6 ) of a vehicle, wherein the charging system ( 1 ) comprises: at least one converter for converting an AC voltage to a DC voltage when charging the battery ( 6 ) and for converting a DC voltage into an AC voltage when operating an electric motor ( 3 ) through the battery ( 6 ), a mains charging port ( 10 ) for connecting an external power supply network to the inverter, a DC link capacitor ( 4 ), and at least one first switching unit ( 11a . 11b ) for separating an electrically conductive connection between the converter and the electric motor ( 3 ), characterized by a directly and by means of a third switching unit ( 22 ) interruptible with the battery ( 6 ) two-way charge controller ( 5 ) for charging-lowering an input voltage from the external power grid during the charging of the battery ( 6 ) and for charging an input voltage from the battery ( 6 ) for charging between the two-way charge controller ( 5 ) and the inverter ( 2 . 2a . 2 B ), parallel-connected capacitor ( 4 ), the two-way charge controller ( 5 ) one of an operating circuit for operating the electric motor ( 3 ) through the battery ( 6 ) independent charging circuit with the battery ( 6 ) for charging the battery ( 6 ) and the capacitor ( 4 ), wherein the charging circuit has a first positive conductor ( 12a . 12b ) and a negative conductor ( 13 ). Charging system according to claim 1, characterized in that the operating circuit a second positive conductor ( 14 ) and a common with the charging circuit negative conductor ( 13 ), wherein the operating circuit by means of a on the second positive conductor ( 14 ) arranged second switching unit ( 15 . 15a . 15b ) is interruptible. Charging system according to one of claims 1 or 2, characterized in that the first positive conductor ( 12a . 12b ) a first line section ( 12a ) from the capacitor ( 4 ) to the two-way charge controller ( 5 ) and a second line section ( 12b ) from the two-way charge controller ( 5 ) to a positive pole ( 6a ) of the battery ( 6 ), wherein the second switching unit ( 15 ) between the charging circuit and the positive pole ( 6a ) of the battery ( 6 ) is switched. Charging system according to one of the preceding claims, characterized in that the two-way charge controller ( 5 ) parallel to the battery ( 6 ) is switched. Charging system according to one of the preceding claims, characterized in that the two-way charge controller ( 5 ) at least two circuit breakers ( 7 ), each circuit breaker ( 7 ) each have a transistor ( 9 ) in parallel with a diode ( 8th ). Charging system according to one of the preceding claims, characterized in that the two-way charge controller ( 5 ) at least one charge control element ( 20 ) for the charging power control and control of the battery ( 6 ) having. Charging system according to claim 6, characterized in that the charging control element ( 20 ) at least with the circuit breaker ( 7 ) and / or the third switching unit ( 22 ) of the two-way charge controller ( 5 ) connected is. Charging system according to one of the preceding claims, characterized in that the capacitor ( 4 ) is used for caching of electrical energy to inrush surges when plugging in the power grid charging port ( 10 ) to the external power supply network. Charging system according to one of the preceding claims, characterized in that the inverter at least two circuit breakers ( 7 ), each one transistor ( 9 ) in parallel with a diode ( 8th ), wherein the two power switches ( 7 ) are connected in series, and wherein the power grid charging port ( 10 ) at a node between the two circuit breakers ( 7 ) connected. Charging system according to one of the preceding claims, characterized in that the inverter three series-connected in parallel to each other from each at least two circuit breakers ( 7 ), wherein the series connections parallel to the capacitor ( 4 ) are switched. Charging system according to one of the preceding claims, characterized in that the converter is a double converter ( 2 ), which is a first ( 2a ) and a second inverter ( 2 B ) for the conversion of the DC voltage of the battery ( 6 ) in an AC voltage for the electric motor ( 3 ) when operating the electric motor ( 3 ) or an AC voltage of the external power supply network into a DC voltage for the battery ( 6 ) while charging the battery ( 6 ), wherein the electric motor ( 3 ) each with the first ( 2a ) and the second inverter ( 2 B ) connected is. Charging system according to one of the preceding claims, characterized in that the two-way charge controller ( 5 ) Part of the battery ( 6 ).

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