DE202017007055U1 - loader - Google Patents

Abstract

Charging device (2) for charging an electrical energy store (3) of a motor vehicle (1), in which the electrical energy store (3) is set up to be charged by a DC charging device (5), wherein an output voltage (6) of the DC charging device (5) an electrical drive unit (4) of the motor vehicle is convertible to a charging voltage (7) and the electrical energy store (3) is set up to be charged with the charging voltage (7), the DC charging device (5) being adapted to a first ripple current (8) and the electric drive unit (4) is arranged to generate a second ripple current (9), wherein the DC charging device (5) and the electric drive unit (4) are configured to generate a third ripple current (10) and the third ripple current (10 ) is deliverable to the electrical energy storage device (3), characterized in that the first ripple current (8) and the second ripple current (9) for minimizing the AC component of the third ripple current (10) can be generated coordinated with each other.

Description

The invention relates to a charging device which is set up for charging an electrical energy store of a motor vehicle. The electrical energy store is charged by a DC charging device. An output voltage of the DC charging device is converted by an electric drive unit of the motor vehicle into a charging voltage and the electrical energy store is charged with the charging voltage. The DC charging device generates a first ripple current and the electric drive unit generates a second ripple current. The DC charging device and the electric drive unit together generate a third Rippelstrom and the third Rippelstrom is delivered to the electrical energy storage. Furthermore, the invention relates to a charging device for charging an electrical energy storage of a motor vehicle.

It is known to use an electric drive unit of a motor vehicle for DC voltage adjustment. The electric drive unit is designed in particular as a main drive unit or as an electric motor. In the known approach, at least part of the electric drive unit is used to adapt or convert DC voltage. For example, by the electric drive unit then a voltage of 400 V to a voltage of 800 V are set high. For example, from a DC charging device or a DC charging station a DC voltage of 400 V can be provided and an electrical energy storage or a battery of the motor vehicle can be charged with 800 V after an output voltage of the DC charging device has been adjusted by the electric drive unit to the charging voltage.

By using the electric drive unit as a DC-DC converter, for example, can be dispensed with a separate DC-DC converter in the vehicle. The disadvantage of this may be that the electric drive unit, which is designed primarily to drive the motor vehicle, only has a traction inverter. Typically, in such a traction inverter, due to the semiconductor switch technology used (e.g., insulated-gate bipolar transistor, IGBT), the clock frequency is limited to 20 kHz. However, a separate DC-DC converter designed primarily for DC conversion purposes may typically be operated at a clock frequency of up to 150 kHz due to its semiconductor switch technology (e.g., silicon carbide metal oxide semiconductor field-effect transistor, SiC MOSFET, for short). The higher the Tatfrequenz is the less or less disturbing is the AC component of a ripple current.

It is an object of the present invention to provide a charging device, in which or with which an electrical energy storage device of a motor vehicle can be charged with less interference.

This object is achieved by the charging device according to claim 1.

To understand the operation of the charging device, its mode of action is described below by means of a method. It is charged an electrical energy storage. The electrical energy storage is charged by a, in particular motor vehicle external, DC voltage charging device. An output voltage of the DC charging device is converted by an electric drive unit of the motor vehicle into a charging voltage and the electrical energy store is charged with the charging voltage. The DC charging device generates a first ripple current and the electric drive unit generates a second ripple current. The DC charging device and the electric drive unit together generate a third ripple current. In particular, the third ripple current is generated by the first ripple current and the second ripple current. The third ripple current is discharged, in particular directly, to the electrical energy store. The first ripple current and the second ripple current are generated matched to minimize the AC component of the third ripple current.

The invention is based on the finding that the AC component of the third ripple current, which is composed of the first ripple current and the second ripple current, can be minimized or reduced if the first ripple current and the second ripple current are generated in a coordinated manner.

The respective ripple current can have any shape, for example a rectangular shape, a sawtooth shape or another current shape.

For example, the first ripple current can be generated such that a maximum of an amplitude of the first ripple current is not superposed with a maximum of an amplitude of the second ripple current. In the case of an overlay, the amplitudes of the first and of the second ripple currents would add, given the same phase position. The magnitudes of the amplitude of the third ripple current would thereby become greater than those of the first or second ripple current, and undesired electrical or electromagnetic interference effects would occur in an excessive manner. The electromagnetic Compatibility (EMC) of the charging device can be reduced.

Usually, smoothing capacitors are used to minimize current ripple. An advantage of the present invention is that a smoothing capacitor for smoothing the third ripple current can be dispensed with if the first ripple current and the second ripple current are generated in a coordinated manner.

The DC charging device is arranged in particular outside the motor vehicle and may be formed, for example, as a DC charging station.

As ripple current or superimposed alternating current, referred to in electrical engineering, an alternating current of arbitrary frequency and waveform superimposed on a direct current. This can also lead to a polarity change. The current type of ripple current is sometimes referred to in technical publications as "pulsating direct current". He occurs, for example, behind the rectification of an AC voltage on the subsequent filter capacitor.

Preferably, it is provided that, when generating the ripple currents, a spectrum of the first ripple current and a spectrum of the second ripple current are matched to one another. By tuning the spectra, in particular, it is prevented that amplitudes in the frequency spectrum collide or add constructively (superposition).

Furthermore, it is preferably provided that an amplitude of the spectrum of the first ripple current and an amplitude of the spectrum of the second ripple current are generated offset from one another. The staggered generation prevents the amplitudes, in particular at their maximum, from being superimposed and thus adding up to a common higher amplitude. The first ripple current and the second ripple current are then generated in such a way that when the two ripple currents meet, there is an offset of the maximum of the respective amplitudes. Thus, the first ripple current and the second ripple current are preferably generated such that a maximum of the amplitude of the first ripple current coincides with a minimum of the amplitude of the second ripple current. The phase position of the first ripple current and the second ripple current can be disregarded in the offset generation. Thus, the phase position of the first ripple current, for example, the phase angle of the second ripple current accordingly. To set the frequencies, a clock frequency of the DC charging device and / or a clock frequency of the electric drive unit can be set so that it does not collide with the clock frequency of the other in the frequency spectrum. The same can be avoided for the higher order harmonics of the two clocked elements in the charge path, in particular the third harmonic due to the superposition of three inductor currents in the three electric motor phases, or, for example, the sixth harmonic in the superimposition of the inductor currents of a six-phase dedicated DC to voltage converter used for DC charging.

Preferably, it is provided that an amplitude of the spectrum of the first ripple current and an amplitude of the spectrum of the second ripple current, in particular completely, adding or, in particular completely, are subtractively superimposed generated. In particular, it is provided that a maximum of an amplitude of the first ripple current is superposed with a maximum of an amplitude of the second ripple current. However, it is preferably provided when superimposing the spectra that a phase position of the first ripple current, in particular by 180 °, is generated rotated to a phase position of the second ripple current. As a result, the first ripple current and the second ripple current overlap, however, with opposite phase positions whereby the third ripple current is minimized or at best even at least partially extinguished.

Furthermore, it is preferably provided that, when generating the ripple currents, a phase position of the first ripple current and a phase position of the second ripple current are matched to one another. By tuning the respective phase position of the time of the respective zero crossings is matched. In particular, a constant phase shift is then obtained.

Furthermore, it is preferably provided that, when tuning the phase position, the phase position of the first ripple current and the phase position of the second ripple current are generated offset by 180 ° to one another. The first ripple current and the second ripple current are thus generated in phase opposition or with phase opposition. It is advantageous that thereby minimize the first Rippelstrom and the second Rippelstrom each other or even extinguish at least partially.

Furthermore, it is preferably provided that, in particular only, the first ripple current is generated adapted to minimize the third ripple current to the second ripple current. Thus, it is preferably provided that only the first ripple current is adjusted, and thus only the DC voltage charging device for adjusting the first ripple current is controlled, while the electric drive unit, the second ripple current can provide uncontrolled. However, it is preferably intended that the DC charging device is informed about the amplitude and / or the phase position of the second ripple current.

Furthermore, it is preferably provided that, in particular, only the second ripple current is generated adapted to minimize the third ripple current to the first ripple current. In this embodiment, it is preferably provided that, in particular only, the electric drive unit is controlled such that the third ripple current is minimized. The electric drive unit is then informed, for example, about an amplitude and / or a phase position of the first ripple current and can adapt the second ripple current to the first ripple current as described above. The third ripple current can thereby be effectively minimized and the electrical energy storage can be charged more safely.

Furthermore, it is preferably provided that the first ripple current and the second ripple current are generated by means of a DC charging communication protocol, which is designed for communication between the DC voltage charging device and the electric drive unit. The DC charging communication protocol may be formed, for example, as a DC charging communication protocol (OCP). By the DC charging communication protocol, for example, the charging of the DC charging device via the electric drive unit to the electrical energy storage is controlled. Preferably, the DC charging communication protocol is extended by the information about the first ripple current and / or the second ripple current, so that the first ripple current and the second ripple current can be generated in a coordinated manner. The extended DC charging communication protocol preferably provides a connection between the DC charging device and the electric drive unit.

It can also be provided that a further electric drive unit of the motor vehicle is used in addition to the electric drive unit for voltage adjustment. The further electric drive unit generates a fourth ripple current. The third ripple current is generated in this case by superposition of the first ripple current, the second ripple current and the fourth ripple current. It is then preferably provided to generate the first ripple current, the second ripple current and the fourth ripple current in order to minimize the third ripple current.

The invention relates to a charging device for charging an electrical energy storage of a motor vehicle. The electrical energy store is set up to be charged by a direct voltage charging device, in particular a motor vehicle external. An output voltage of the DC charging device can be converted by an electric drive unit of the motor vehicle to a charging voltage and the electrical energy store is set to be charged with the charging voltage. The DC charging device is configured to generate a first ripple current and the electric drive unit is configured to generate a second ripple current. The DC charging device and the electric drive unit are further adapted to generate a third Rippelstrom together and the third ripple current is in particular directly, can be delivered to the electrical energy storage. As an important idea of the invention, it is provided that the first ripple current and the second ripple current can be generated in a coordinated manner in order to minimize the alternating current component of the third ripple current.

In particular, a frequency of the first ripple current and / or a frequency of the second ripple current and / or a phase position of the first ripple current and / or a phase position of the second ripple current can be generated coordinated with one another.

The motor vehicle is preferably designed as a passenger car (PKW), but may for example be designed as a utility vehicle, for example as a truck (truck).

Advantageous embodiments of the method according to the invention are to be regarded as advantageous embodiments of the charging device. The subject components of the charging device are each designed to carry out the respective method steps.

Further features of the invention will become apparent from the claims, the figures and the description of the figures. The features and feature combinations mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respectively specified combination but also in other combinations or in isolation, without the frame to leave the invention.

For a more detailed explanation of the mode of operation, methods are shown below that show possible uses of embodiments of the charging device.

For charging an electrical energy store of a motor vehicle, wherein the electrical energy storage by a DC charging device is charged, an output voltage of the DC charging device is converted by an electric drive unit of the motor vehicle into a charging voltage. The electrical energy store is charged with the charging voltage, wherein the DC charging device generates a first ripple current and the electric drive unit generates a second ripple current. The DC charging device and the electric drive unit together generate a third ripple current. The third ripple current is delivered to the electrical energy store.

The first ripple current and the second ripple current are generated matched to minimize the AC component of the third ripple current.

When generating the ripple currents, a spectrum of the first ripple current and a spectrum of the second ripple current can be matched to one another.

An amplitude of the first ripple current and an amplitude of the second ripple current are generated offset to each other.

An amplitude of the first ripple current and an amplitude of the second ripple current can be generated in an additive or subtracting superimposing manner.

When generating the ripple currents, a phase position of the first ripple current and a phase position of the second ripple current can be matched to one another.

When tuning the phase positions, the phase position of the first ripple current and the phase position of the second ripple current can be generated offset by 180 ° to each other.

The first ripple current may be generated adapted to minimize the third ripple current to the second ripple current.

The second ripple current may be generated adapted to minimize the third ripple current to the first ripple current.

The first ripple current and the second ripple current may be generated by means of a DC charging communication protocol adapted for communication between the DC charging device and the electric drive unit.

Embodiments of the invention are explained in more detail below with reference to schematic drawings.

• 1 eine schematische Draufsicht auf ein Kraftfahrzeug mit einem elektrischen Energiespeicher und einer elektrischen Antriebseinheit, und einer kraftfahrzeugexternen Gleichspannungsladevorrichtung;
• 2 eine schematische Darstellung eines Ausführungsbeispiels einer erfindungsgemäßen Ladeeinrichtung mit einem Gleichstromladekommunikationsprotokoll; und
• 3 eine schematische Darstellung eines ersten Rippelstroms und eines zweiten Rippelstroms, welche zusammen einen dritten Rippelstrom erzeugen.

Show it:

• 1 a schematic plan view of a motor vehicle with an electrical energy storage and an electric drive unit, and a motor vehicle external DC charging device;
• 2 a schematic representation of an embodiment of a charging device according to the invention with a DC charging communication protocol; and
• 3 a schematic representation of a first ripple current and a second ripple current, which together generate a third ripple current.

In the figures, identical or functionally identical elements are provided with the same reference numerals.

In 1 is a schematic plan view of a motor vehicle 1 and a charging device 2 shown.

The car 1 has an electrical energy storage 3 and an electric drive unit 4 on. The electrical energy storage 3 is designed to store electrical energy in the form of chemical energy and may be present for example as an accumulator. The electrical energy storage 3 can also be present through several accumulators. According to the embodiment, the electrical energy store 3 a nominal voltage of 800V. The energy storage 3 but can also have a variety of other nominal voltages.

The electric drive unit 4 is formed according to the embodiment as an electric motor. Furthermore, the electric drive unit 4 formed according to the embodiment as the main traction unit. The car 1 Accordingly, according to the embodiment, an electric vehicle, which by the electric drive unit 4 is driven. In other embodiments, not shown, for example, a plurality of electric drive units 4 for driving the motor vehicle 1 present or the motor vehicle 1 For example, it may be additionally configured with an internal combustion engine. The car 1 Thus, for example, it can also be present as a hybrid vehicle.

The electric drive unit 4 is used here as a DC-DC converter. So be at least parts of the electric drive unit 4 used to adjust a DC voltage.

Furthermore, a DC charging device 5 shown. The DC charging device 5 is arranged according to the embodiment outside the vehicle and may be formed, for example, as a diverse DC voltage source. So can the DC charging device 5 For example, be designed as a DC charging station in a public parking lot or in a private garage. According to the embodiment, the DC charging device provides 5 a nominal voltage of 400V ready.

According to the embodiment, the DC charging device 5 directly with the electric drive unit 4 electrically connected and the electric drive unit 4 is directly with the electrical energy storage 3 electrically connected.

The DC charging device 5 represents an output voltage 6 ready. The output voltage 6 corresponds to the nominal voltage of the DC charging device 5 and is 400 V according to the embodiment.

The output voltage 6 is by the electric drive unit 4 to a charging voltage 7 changed. By the operation of the electric drive unit 4 as a DC-DC converter, the output voltage 6 So to the charging voltage 7 customized. The charging voltage 7 is according to the embodiment 800 V and thus corresponds to the nominal voltage of the electrical energy storage 3 , The charging voltage 7 So is the electric drive unit 4 to the electrical energy storage 3 issued.

The DC charging device 5 generates an (unwanted) first ripple current 8th , The first ripple current 8th may, for example, arise as unwanted by-product of rectification.

The electric drive unit 4 generates an (unwanted) second ripple current 9 , The second ripple current 9 is generated for example by the fact that the electric drive unit 4 for voltage conversion, the current is inverted from DC to AC and then rectified into DC.

Because the first ripple current 8th the electric drive unit 4 is supplied, this combines with the second ripple current 9 , As a combination of the first ripple current 8th and the second ripple current 9 is finally from the electric drive unit 4 a third ripple current 10 output. The third ripple current 10 So it comes together from the DC charging device 5 and the electric drive unit 4 generated. The third ripple current 10 is according to the embodiment directly to the electrical energy storage 3 issued.

The first ripple current 8th and the second ripple current 9 are now generated matched to each other to minimize the third ripple current. Due to a lower AC component of the third ripple current 10 less electrical or electromagnetic interference is generated.

When tuning the first ripple current 8th and the second ripple current 9 becomes a spectrum according to the embodiment 11 of the first ripple current 8th and a spectrum 12 of the second ripple current 9 coordinated. In particular, an amplitude of the first ripple current becomes 8th and an amplitude 19 of the second ripple current 9 coordinated. By tuning the spectrum 11 of the first ripple current 8th and the spectrum 12 of the second ripple current 9 may be a respective maximum of a respective amplitude 18 . 19 be generated so that they do not coincide, so do not completely overlap and thus do not sum up completely. This can be prevented by the unavoidable combination of the first ripple current 8th and the second ripple current 9 a larger maximum of an amplitude of the third ripple current 10 is generated as this already by the first ripple current 9 or the second ripple current 9 before the combination of ripple currents 8th . 9 was present.

When tuning the first ripple current 8th and the second ripple current 9 becomes according to the embodiment, a phase position 13 of the first ripple current 8th and a phasing 14 of the second ripple current 9 coordinated. When tuning the phase position, the phase position 13 of the first ripple current 8th preferably offset by 180 ° to the phase position 14 of the second ripple current 9 generated.

In the offset generation of the phase positions 13 . 14 For example, it is intended that the spectrum 11 of the first ripple current 8th and the spectrum 12 of the second ripple current 9 be generated completely superimposed, that is generated in such a way that the respective maxima or minima fall on each other and cause by the phase opposition that they cancel each other or at least partially extinguished.

It may now be, for example, that the first ripple current 8th at the second ripple current 9 is adjusted or that the second ripple current 9 to the first ripple current 8th is adjusted or that the first ripple current 8th and the second ripple current 9 be adjusted equally.

2 shows the charging device 2 which the electric drive unit 4 and the DC charging device 5 includes. The electric drive unit 4 and the DC charging device 5 are via a high voltage connection 15 and a control connection 16 connected with each other. The control connection 16 is designed for example as a low-voltage connection. The high voltage connection 15 and the control connection 16 For example, they may be formed separately from each other or may be formed in a common cable or in a common line. Through the high voltage connection 15 will be the output voltage 6 from the DC charging device 5 to the electric drive unit 4 transfer.

The control connection 16 is for a DC charging communication protocol 17 educated. About the DC charging communication protocol 17 can the DC charging device 5 with the electric drive unit 4 communicate and exchange information about the charging process or the state of charge.

The DC charging communication protocol 17 is extended according to the embodiment to the first ripple current 8th and the second ripple current 9 to create coordinated with each other. For example, via the DC charging communication protocol, the amplitude 18 of the first ripple current 8th and / or the phase position 13 of the first ripple current 8th to the electric drive unit 4 be transmitted and / or the amplitude 19 of the second ripple current 9 and / or the phase position 14 of the second ripple current 9 can to the dc charger 5 be transmitted.

3 shows the first ripple current 8th and the second ripple current 9 , By the concerted generation of the first ripple current 8th and the second ripple current 9 the third ripple current is minimized. This means that an amplitude of the third ripple current 10 preferably smaller than an amplitude of the first ripple current 8th and / or the second ripple current 9 ,

According to the embodiment, the phase position 13 of the first ripple current 8th and the phase position 14 of the second ripple current 9 offset by 180 °, whereby the vibration of the third ripple current 10 is attenuated or in other words the third ripple current 10 is smoothed.

LIST OF REFERENCE NUMBERS

1

motor vehicle

2

loader

3

electrical energy storage

4

electric drive unit

5

DC charger

6

output voltage

7

charging voltage

8th

first ripple current

9

second ripple current

10

third ripple current

11

Spectrum of the first ripple current

12

Spectrum of the second ripple current

13

Phase angle of the first ripple current

14

Phase angle of the second ripple current

15

High-voltage connection

16

control connection

17

DC charging communication protocol

18

Amplitude of the first ripple current

19

Amplitude of the second ripple current

Claims (4)

Charging device (2) for charging an electrical energy store (3) of a motor vehicle (1), in which the electrical energy store (3) is set up to be charged by a DC charging device (5), wherein an output voltage (6) of the DC charging device (5) an electrical drive unit (4) of the motor vehicle is convertible to a charging voltage (7) and the electrical energy store (3) is set up to be charged with the charging voltage (7), the DC charging device (5) being adapted to a first ripple current (8) and the electric drive unit (4) is arranged to generate a second ripple current (9), wherein the DC charging device (5) and the electric drive unit (4) are configured to generate a third ripple current (10) and the third ripple current (10 ) is deliverable to the electrical energy storage device (3), characterized in that the first ripple current (8) and the second ripple current (9) for minimizing the AC component of the third ripple current (10) can be generated coordinated with each other. Charging device (2) after Claim 1 , wherein a frequency of the first ripple current and a Frequency of the second ripple current can be generated coordinated with each other Charging device (2) after Claim 1 or 2 In which a phase position of the first ripple current and a phase position of the second ripple current can be generated coordinated with one another. Charging device (2) according to one of the preceding claims, further comprising a control connection (16), which is designed for a DC charging communication protocol (17) and the DC charging communication protocol (17) is arranged such that the DC charging device (5) is connected to the electric drive unit (4 ) and exchanging information about the charging state, wherein the DC charging communication protocol (17) is further configured to apply the amplitude (18) of the first ripple current (8) and / or the phase position (13) of the first ripple current (8) to the electric drive unit (4) or to transmit the amplitude (19) of the second ripple current (9) and / or the phase position (14) of the second ripple current (9) to the DC charging device (5) to the first Rippelstrom (8) and To generate the second Rippelstrom (9) matched to each other.

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