DE102019001196A1 - Method for providing a voltage for a vehicle electrical system and on-board charger for this purpose - Google Patents

Abstract

The invention relates to a method for providing a voltage for an electrical system (3) with an on-board charger (1), wherein the on-board charger (1) is supplied with a first DC voltage (U _DC1 ) via a first charging connection (5) and the first DC voltage (U _DC1 ) with a galvanically insulating voltage converter (6) of the on-board charger (1) in a relation to the first DC voltage (U _DC1 ) higher second DC voltage (U _DC2 ) is converted, and the electrical system (3) with the second DC voltage (U _DC2 ) is supplied. With a boost converter (8) of a power factor correction filter (7) of the on-board charger (1) is below a threshold value by the first DC voltage (U _DC1 ), the first DC voltage (U _DC1 ) in a relation to the first DC voltage (U _DC1 ) higher third DC voltage (U _DC3 ) transformed up. The third DC voltage (U _DC3 ) is converted into the second DC voltage (U _DC2 ) with the galvanically insulating voltage converter (6) and thus the on-board network (3) is supplied with the second DC voltage (U _DC2 ). And with an EMC filter (11) formed in front of an input side of the power _{factor correction} filter (7), an input _{noise is} filtered out of the first DC voltage (U _DC1 ). Furthermore, the invention relates to a on-board loader (1).

Description

The invention relates to a method for providing a voltage for an electrical system with a on-board charger, wherein the on-board charger is supplied via a first charging connection with a first DC voltage and the first DC voltage is converted with a galvanically insulating voltage converter of the on-board charger in a relation to the first DC voltage higher second DC voltage is and the electrical system is supplied with the second DC voltage. Furthermore, the invention relates to an on-board charger for charging a battery of a vehicle electrical system.

The DE 10 2016 008 052 A1 describes an energy storage device for a motor vehicle with a first and a second energy storage for storing electrical energy. The energy storage device comprises a charging connection for charging the energy store, an operating connection for operating a consumption to the energy storage device, and a switching device which has a plurality of switching elements and by means of which the energy stores are selectively switchable in series or in parallel. A fifth switching element of the switching device is electrically coupled thereto opposite the polarity of the energy store, and with the fifth switching element, the energy storage independent of the other switching elements of the switching device in series switchable to provide an energy device in a motor vehicle. With the energy storage device, an efficient manner is operated with different voltages, and which in particular meet relevant safety regulations for the operation of an energy storage device in a motor vehicle.

The DE 10 2018 000 491 A1 describes a memory unit for a motor vehicle with at least one energy store, which has at least two sub-strands for storing electrical energy. The memory device comprises at least one charging connection, via which the partial strands can be connected to a current wave and supplied with electrical energy supplied by the current source and thereby to be charged. The memory device likewise comprises a switching device which is connected in series between at least one first switching state in which the drive trains are connected in series for setting a first electrical voltage of the energy store and at least one second switching state can be switched over. With the second switching state, a second electrical voltage of the energy store, which is low in comparison to the first electrical voltage, can be connected in parallel via the drive trains, with a galvanically insulating voltage converter, comprising an on-board charger, being provided.

This results in a disadvantage that depending on the state of charge, the battery can not be fully charged at a battery voltage above a maximum output voltage of a charging station.

The object of the present invention is to provide a method and an on-board charger, with which an improved design of a transmission ratio of a transformer of a DC-DC converter can be performed. This allows a battery, which is below a certain state of charge, to be charged more efficiently.

One aspect of the invention relates to a method for providing a voltage for an electrical system with an on-board charger, wherein the on-board charger is supplied via a first charging connection with a first DC voltage and the first DC voltage with a galvanically insulating voltage converter of the on-board charger in a relation to the first DC voltage higher second DC voltage is converted and the electrical system is supplied with the second DC voltage. A boost converter of a power factor correction filter of the on-board charger is transformed into a second DC voltage higher than the first DC voltage when falling below a limit value by the first DC voltage, wherein the third DC voltage is converted with the galvanically insulating voltage converter in the second DC voltage and thus the second electrical system with the second DC voltage is supplied. With an EMC filter, which is formed in front of the input side of the power factor correction filter, an input control variable is filtered out of the first DC voltage. In particular, with the on-board charger, a vehicle electrical system of a vehicle and / or a battery, in particular a high-voltage battery of a vehicle, are supplied with the voltage. By stepping up the first DC voltage, which falls below a certain threshold, into the third DC voltage by the boost converter of the power factor correction filter, in particular the galvanically insulating voltage converter can be designed more efficiently. The gear ratio of a transformer of the insulating voltage converter can be designed for the transformer transformation ratio in the AC charging operation. In particular, by feeding the first DC voltage to the AC terminal of the on-board charger, the first DC voltage can be increased to a predetermined value by the boost converter. Thus, especially in the critical case when DC charging on the primary side of the insulating voltage converter can be raised to a predetermined voltage. The transformation ratio can be adjusted with the design to an AC Charging case can also be easily used for DC charging. For example, the threshold can be set at a voltage of 373 volts. This results, for example, a transmission ratio of 1: 1.6. In particular, the DC-to-DC converter boosts a DC voltage that is below, for example, 373 volts to at least 373 volts.

In particular, the voltage level of the first DC voltage is equal to the voltage level of the third DC voltage. With the aid of the galvanically insulating voltage converter, for example, the first DC voltage, which is for example 400 volts, in the second DC voltage, which is for example 800 volts is transformed up.

With the EMC filter filtering can be performed especially when supplying the on-board charger with AC voltage and also disturbing input variables can be filtered out during DC charging operation. As a result, in particular requirement of the electromagnetic compatibility can be better achieved.

Another aspect of the invention relates to an on-board charger for charging a battery of a vehicle electrical system with a charging connection, with which a first DC voltage can be provided and with a galvanically insulating voltage converter, with which the first DC voltage is convertible to a second DC voltage. The on-board charger comprises an up-converter of a power factor correction filter, which transforms the first DC voltage into a third DC voltage when a limit value is distinguished by the first DC voltage. With a galvanically insulating voltage converter of the on-board charger, the third DC voltage can be transformed into the second DC voltage. Also, the on-board charger comprises an EMC filter, which is formed in front of an input side of the power factor correction filter and is designed to filter out an input variable from the first DC voltage. With the on-board charger can be provided for example for the electrical system and / or the battery, a DC voltage of 400 volts DC or 800 volts DC. For example, the on-board charger can be supplied with DC voltage with a DC charging station or can be supplied with AC voltage via an AC voltage source.

For example, the voltage converter is designed to be unidirectional, but can optionally be bidirectional and, for example, to enable the functionality of bidirectional charging. In order to avoid DC fault currents in the event of an insulation fault in a high-voltage system of the motor vehicle, which would render ineffective an AC fault current switch in the building services, disconnectors are preferably provided in the electrical system to DC charging lines. This avoids insulation design of the entire high-voltage system for reinforcement of the insulation.

For example, with the on-board charger, the supply of any auxiliary consumers with electrical energy during charging of the battery can be performed.

Overall, with the on-board charger and by means of external power sources, the battery can be fully charged, through which a comparison with the first electrical voltage lower output voltage is provided. Furthermore, a multiple use of the galvanic voltage converter can be realized in the on-board charger, so that the number of components and additionally the weight and thus the space requirement and the costs can be kept low. For example, the boost converter may be a clocked boost converter. With the clocked boost converter, an input current can be brought into phase with the AC input voltage. For example, the output voltage can be adjusted to a constant value that corresponds to at least the value of the peak AC voltage or can be selected to be larger.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or in the figures alone can be used not only in the respectively specified combination but also in other combinations or in isolation, without the scope of To leave invention.

• 1 eine schematische Darstellung eines erfindungsgemäßen Bordladers; und
• 2 eine beispielhafte Darstellung eines Leistungsfaktorkorrekturfilters.

The following figures show in:

• 1 a schematic representation of a on-board charger according to the invention; and
• 2 an exemplary representation of a power factor correction filter.

In particular, with the on-board loader 1 a battery 2 of a vehicle electrical system 3 Loading. For example, it may be at the battery 2 to a high-voltage battery and the electrical system 3 to act a high-voltage electrical system, in particular the electrical system 3 one or more secondary consumers 4 may include. The battery 2 and the electrical system 3 may in particular be part of a motor vehicle. For example, the motor vehicle as a hybrid vehicle or particularly preferably as Be formed electric vehicle and comprise at least one electric machine, with which the motor vehicle is electrically driven. For example, with the battery 2 the electric machine can be supplied with electrical energy or with electric current, whereby the electric machine can be operated as an electric motor. By means of the electric motor, the motor vehicle can thus be driven electrically.

The on-board loader 1 is through a charging port 5 with a first DC voltage U _DC1 provided. At the charging port 5 it may in particular be a DC voltage connection of an electric DC charging station for a motor vehicle. For example, as well as the battery 2 with the charging port 5 with the first DC voltage U _DC1 be supplied. The on-board loader 1 in particular comprises a galvanically insulating voltage converter 6 with which the first DC voltage U _DC1 in a second DC voltage U _DC2 can be converted. For the galvanically isolated voltage transformer 6 it may in particular be a DC-DC converter. For example, the first DC voltage U _DC1 a value of 400 volts, and with the help of the voltage converter 6 can from these 400 volts, the second DC voltage U _DC2 be transformed with now 800 volts. The second DC voltage U _DC2 especially for supplying the battery 2 and / or the electrical system 3 and / or the secondary consumer 4 be used.

For example, the battery includes 2 a switching device with switches S1 to S7 , The switching device and thus the switches S1 to S7 are switchable between at least a first switching state and at least a second switching state. For example, a battery voltage of 800 volts may be provided with the first switching state, and with the second switching state, a second battery voltage of 400 volts may be provided.

The on-board loader 1 In particular, it includes a power factor correction filter 7 , The power factor correction filter 7 can be designed in particular as a PFC circuit. The power factor correction filter 7 In particular, it comprises an up-converter 8th and a rectifier 9 , With the up-converter 8th , which can be configured as a boost converter, can fall below a limit value by the first DC voltage U _DC1 the first DC voltage U _DC1 in a third DC voltage U _DC3 be transformed. For example, a threshold value of 373 volts can be set, and once the first dc voltage U _DC1 this 373 volts falls below, the first DC voltage U _DC1 through the up-converter 8th back to an original value of the first DC voltage U _DC1 be transformed up. In particular, the first DC voltage U _DC1 400 Volts DC. The highly transformed first DC voltage U _DC1 through the up-converter 8th , in particular the third DC voltage U _DC3 can do so with the voltage transformer 6 in the second DC voltage U _DC2 being transformed.

The on-board loader 1 includes a switching unit 10 , with which in particular the first DC voltage U _DC1 can be added. In operation of the on-board loader 1 when DC charging as a DC voltage converter is the switching unit 10 always closed. In particular, the on-board loader includes 1 an EMC filter 11 , with which disturbing input variables from the first DC voltage U _DC1 can be filtered out. The EMC filter 11 For example, at the input side of the power factor correction filter 7 be arranged. In particular, the EMC filter 11 used for a DC charging operation at half battery voltage of the battery. For example, by raising the first DC voltage U _DC1 in a third DC voltage U _DC3 be sure that at the input of the voltage converter 6 always a voltage of for example 400 volts DC is applied. As a result, in DC charging operation, the transmission ratio of a transformer of the voltage converter 6 not be constantly redesigned.

For example, the on-board loader 1 are also supplied via an AC voltage charging with electrical energy. This is the on-board loader 1 via a second from the first charging port 5 different second charging port 12 with an alternating voltage U _AC provided. In particular, the AC unit is the switching unit 10 of the on-board loader 1 open. The AC voltage U _AC in particular by a rectifier 9 of the power factor correction filter 7 in a fourth DC voltage U _DC4 be directed or converted. The fourth DC voltage U _DC4 preferably has the same voltage level as the first DC voltage U _DC1 , The fourth DC voltage U _DC4 especially with the voltage converter 6 of the on-board loader 1 in the second DC voltage U _DC2 being transformed. At the second charging port 12 it may be, for example, a conventional AC power outlet.

The 2 shows for example a schematic representation of the power factor correction filter 7 , which in this example is represented by a conventional PFC circuit. In the case of the on-board loader 1 with the AC voltage U _AC through the second charging port 12 is supplied, the AC voltage U _AC with the rectifier 9 rectified. At the rectifier 9 For example, it can be a Diode rectifier act, which consists of a first diode 1 , a second diode 2 , a third diode D3 and a fourth diode D4 consists. In this case, the rectified fourth DC voltage becomes U _DC4 using the boost converter, especially as a boost converter 8th , in the third DC voltage U _DC3 changed. The boost converter or the boost converter 8th includes, for example, a coil N _B , a diode D _B , a capacitor C _B and a semiconductor switch S _B ,

In the DC charging operation of the on-board charger 1 becomes the rectifier 9 the PFC circuit is not needed. The up-converter 8th in particular with the first DC voltage U _DC1 supplied, wherein the first DC voltage U _DC1 in the third DC voltage U _DC3 can be raised.

LIST OF REFERENCE NUMBERS

1

board charger

2

battery

3

board network

4

In addition to consumer

5

first charging port

6

DC converter

7

Power factor correction

8th

boost converter

9

rectifier

10

switching unit

11

EMC filters

12

second charging port

C _B

capacitor

D1 to D4

first to fourth diode

D _B

diode

L _B

Kitchen sink

S _B

Semiconductor switches

U _DC1

first DC voltage

U _DC2

second DC voltage

U _DC3

third DC voltage

U _DC4

fourth DC voltage

U _AC

AC

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102016008052 A1 [0002]
• DE 102018000491 A1 [0003]

Claims (5)

Method for providing a voltage for an electrical system (3) with an on-board charger (1), wherein - the on-board charger (1) is supplied with a first DC voltage (U _DC1 ) via a first charging connection (5), and - the first DC voltage (U _DC1 ) is converted with a galvanically insulating voltage converter (6) of the on-board charger (1) into a second DC voltage (U _DC2 ) higher than the first DC voltage (U _DC1 ), and - the vehicle electrical system (3) with the second DC voltage (U _DC2 ) is supplied, characterized in that - with a boost converter (8) of a power factor correction filter (7) of the on-board charger (1), when _{falling below} a limit value by the first DC voltage (U _DC1 ), the first DC voltage (U _DC1 ) in one compared to the first DC voltage (U _DC1 ) higher third DC voltage (U _DC3 ) is up-converted, wherein - the third DC voltage (U _DC3 ) with the galvanically insulating voltage converter (6) in the second DC voltage (U _{DC 2} ) is converted and, thus, the on-board network (3) with the second DC voltage (U _DC2 ) is supplied, and wherein - with an EMC filter (11) which is formed in front of an input side of the power _{factor correction} filter (7), is from the first DC voltage (U _DC1 ) filtered out an input disturbance. Method according to Claim 1 , characterized in that a direct voltage connection is provided with the first charging connection (5). Method according to one of the preceding claims, characterized in that the on-board charger (1) is supplied with an alternating voltage instead of the supply with the first DC voltage (U _DC1 ) via a second charging connection (12) which is different from the first charging connection (5). Method according to Claim 3 , characterized in that the AC voltage with a rectifier (9) of the power _{factor correction filter} (7) is converted into a fourth DC voltage (U _DC4 ), and the fourth DC voltage (U _DC4 ) with the galvanically insulating voltage converter (6) of the on-board charger (1) is converted into the second DC voltage (U _DC2 ), wherein in an AC voltage supply of the on-board charger (1) with the second DC voltage (U _DC2 ), the electrical system (3) and / or a battery (2) are supplied. On-board charger (1) for charging a battery (2) of a vehicle electrical system (3) with - a charging connection (5), with which a first DC voltage (U _DC1 ) can be provided, - a galvanically insulating voltage converter (6), with which the first DC voltage (U _DC1 ) into a second DC voltage (U _DC2 ) is, characterized by , - a _boost converter (8) of a power _{factor correction filter} (7), which _{falls below} a threshold value by the first DC voltage (U _DC1 ), the first DC voltage (U _DC1 ) is transformed into a third DC voltage (U _DC3 ), - the galvanically insulating voltage converter (6), with which the third DC voltage (U _DC3 ) is transformable into the second DC voltage (U _DC2 ), and - an EMC filter (11), which is formed in front of an input side of the power _{factor correction filter} (7), for filtering out an input variable from the first DC voltage (U _DC1 ).

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