DE102018203514A1 - A method for transmitting electrical power to an electrical energy storage of a vehicle electrical system and vehicle electrical system - Google Patents

Abstract

A method for transmitting electrical power to an electrical energy store (ES) of a vehicle electrical system (BN) provides that in an AC direct charging mode the power is supplied by a rectifier (GR) of the vehicle electrical system (BN) powered by an AC charging connector (ACLB) is transmitted directly to the energy storage (ES) of the vehicle electrical system (ES). In an AC adaptive charge mode, the power from the rectifier (GR) is transferred to the energy store (ES) via an inverter (I) and from the inverter (I) via an electric machine (EM).
Furthermore, a vehicle electrical system (BN) for carrying out the method is described.

Description

Motor vehicles with electric drive have an electrical energy storage in the form of a traction battery that feeds the electric drive. In order to charge the energy storage, a charging connection is attached to such a motor vehicle. An external power source can be connected via this charging connection.

In order to control the charging of the energy storage, a power electronics is housed in the motor vehicle. Since this is designed for high power of more than 10 kW or more than 100 kW and also has to cope with different and each variable voltage levels at the charging port and the energy storage, resulting in significant costs for the power electronics.

It is therefore an object of the invention to provide a way by which electrical power can be transmitted to the energy storage of the vehicle electrical system with less effort.

This object is solved by the subject matters of the independent claims. Further embodiments, features and advantages will become apparent from the dependent claims, the description and the figure.

It is proposed to provide a rectifier, which is connected to the AC charging port for transmitting AC power between an AC charging port and an energy storage of a vehicle electrical system. Depending on the voltage levels on the DC side of the rectifier and on the energy storage either the output from the rectifier power is transmitted directly (in particular without voltage conversion) to the energy storage or transmitted via an inverter and an electrical machine connected thereto (i.e., downstream) to the energy storage. In the case of direct transmission, power dissipation is only generated in the rectifier (and not in the inverter), while in transmission via the inverter and the electric machine (as well as via the upstream rectifier), these two components can be operated as a DC-DC converter to different voltage levels between rectifier and To compensate for energy storage. In an AC direct charging mode is thus transmitted directly and in an AC adapter charging mode, the power is passed through the inverter and the electric machine between the rectifier and the energy storage. In particular, power factor correction filtering (PFC filtering) is performed in both modes in the rectifier. Furthermore, rectification is performed in both modes in the rectifier. In the AC adjustment charging mode, no step-up conversion is preferably performed in the rectifier. In the AC direct charging mode, an up-conversion is preferably performed, in particular an up-conversion that goes beyond a voltage boost to perform the power factor correction filtering. With power factor correction filtering, the voltage can be increased slightly, in particular by no more than 5%, 7%, 10%, 15%) to perform the filtering. This is understood to be the voltage boost required to perform power factor correction filtering. The up-conversion goes beyond this voltage increase and is associated with an increase in voltage by more than the voltage increase in the PFC filtering, such as an increase of more than 5%, 7%, 10%, 15% and preferably at least 50%. , 100%, 150% or 200%. The increase or increase in voltage refers to the output voltage of the rectifier relative to the peak-to-peak value of the (possibly chained) voltage at the AC connection.

It is executed depending on the ratio of the voltage levels between the rectifier and the energy storage of the AC direct charge mode or the AC adjustment charge mode. This makes it possible to take into account the voltage level of the energy store, which changes during charging, and different voltages or connection constellations on the AC power connection, especially since the AC power connection (depending on the charging station) can be one or more phases occupied.

A method for transmitting electrical power to an electrical energy store of a vehicle electrical system is described. The electrical energy store is preferably an accumulator, for example a traction accumulator, which may be in particular a lithium accumulator. The electrical energy store is in particular a high-voltage battery. The electric power is transmitted from a charging station or other electrical energy source outside the vehicle electrical system. However, it is also possible to transfer power in the reverse direction. The vehicle electrical system is in particular a high-voltage vehicle electrical system. The prefix "high-voltage" designates a rated voltage that is above 60 V, in particular a nominal voltage of at least 120 V, 300 V, 350 V, 380 V or at least 450 V or 600 V, for example 380 V, 400 V or 800 V.

In an AC direct charging mode, the power from a rectifier (especially from its DC side) is transmitted directly to the energy storage. In this Context means "direct" that no voltage conversion is performed between energy storage and rectifier. The rectifier may be an uncontrolled rectifier, but is preferably a controlled rectifier, preferably with the function of performing power factor correction filtering (on the AC side of the rectifier or charging port), in particular increasing the power factor and / or reducing overshoot rates. The rectifier is powered by an AC charging port of the vehicle electrical system. The AC charging terminal is connected to the rectifier, in particular to an AC side of the rectifier. It can be provided that the rectifier performs a (DC) up-conversion in addition to the rectification, in particular an up-conversion, which goes beyond a voltage increase, which is due to the PFC filtering. The rectifier may thus be configured to perform an up-conversion that results in a voltage whose level is substantially above the peak-to-peak voltage of the (possibly chained) AC voltage at the AC charging port. An increase of no more than approximately 5%, 7%, 10% or 15% is not considered a substantial increase. A non-substantial increase is added to the PFC filtering and not to the up-conversion (in the AC direct charging mode).

As an up-conversion, an increase in the rectified voltage over the peak-to-peak voltage of the (possibly interlinked) AC voltage at the AC charging port will exceed, in particular, more than one voltage boost associated with PFC filtering. The up-conversion is preferably performed by controlling the switches of the PFC-capable rectifier, in particular without voltage conversion by a dedicated, a rectifier circuit downstream voltage converter (DC / DC converter). In particular, the up-conversion is performed in the AC direct-charge mode, and is not performed in the AC-adaptive charge mode (in which only a voltage boost associated with the PFC function is performed). The rectifier is thus in particular equipped with a voltage boost function (corresponding to the up-conversion). This function can be performed in AC direct charging mode and is not operated in AC adjustment mode. In the AC adjustment mode, the inverter and the electric machine are operated as buck converters.

In an AC adaptation charging mode, the power is transmitted from the rectifier to the energy storage via an inverter and via an electrical machine. The inverter (in particular its DC side) is connected to the DC side of the rectifier. The AC side of the inverter is connected to the electric machine, in particular to phase or winding terminals of the electric machine. The power is thus transmitted from the inverter via the electric machine to the energy storage. In this case, the power is transmitted via at least one winding or along at least one winding section of the electrical machine. In particular, the power can be transmitted via the electric machine by the power is fed to at least one phase connection of the electric machine and output from the (opposite) star point. This phase connection is also referred to as external phase connection. The power is transmitted via the inductance of the at least one winding (or winding section) of the electric machine.

When transmitting the power via the inverter and the electrical machine connected thereto, the inverter is operated together with the electric machine as a buck converter (buck converter) or as a synchronous converter in the buck converter mode. In this case, at least one power switch of the inverter forms at least one switch of the buck converter while the at least one winding of the electrical machine is operated as an inductance of the buck converter. The inverter and electric machine may form a single or cascaded buck converter.

The inverter or at least one power switch thereof is driven to form a down-converting DC-DC converter together with the at least one winding of the electric machine. The down-converting DC-DC converter is also referred to as a down-converting DC / DC converter. A desired voltage for the voltage level delivered to the electric machine (i.e., the voltage at at least one inner phase terminal or star point) may be predetermined, such as from a charge controller which may be upstream of the control of the power switches of the inverter. When operating the electric machine together with the inverter as a DC-DC converter, the neutral point may be resolved, i. the inner phase terminals are separated from each other (all or a subset thereof).

A switching device may be used to select one of the at least two possible modes (AC direct charging mode or AC adjusting charging mode). In the AC direct charging mode, a switching device connects the Rectifier with the energy storage, in particular in a direct manner (ie without voltage conversion). A switch of the switching device transmits the power. In the AC matching charging mode, the switching device connects the rectifier to the inverter, and produces a power path that leads through the inverter and the electric machine. For this purpose, a further switch of the switching device can be provided, which in this case transmits the power. The further switch and the former switch preferably together form the switching device. The two switches are alternately closed, ie when one switch is closed, the other switch is open. In an inactive mode both switches can be open.

The rectifier rectifies the power in at least one of the AC charging modes, preferably in the AC direct charging mode and in the AC adjusting charging mode. The rectifier is in particular a controlled rectifier. Furthermore, the rectifier performs a Power Factor Correction (PFC) function, particularly on the AC side of the rectifier. This increases the power factor, reduces harmonic components, or both. The rectifier can be designed as a Vienna rectifier. To perform the power factor correction filtering, the rectifier comprises (for each phase) at least one energy storage device, for example a coil or a capacitor. The energy storage device may be provided in series with the rectifier's phase terminals (on the AC side), such as a series inductance (for each phase). Alternatively or additionally, an energy-storing component may be connected in parallel with different phase connections, for example in a triangular configuration or in a star configuration. The energy-storing component may be designed in the form of parallel capacitors, by means of which the phase connections are connected to one another. The rectifier can thus be designed for power correction filtering or power correction filtering (FIG. PFC , power factor correction). A power correction filter can be equated with the change in power factor mentioned here or with the increase of the power factor and a reduction of harmonic components.

The inverter can be a controlled full-wave bridge, in particular with several phases, for example a multiphase BnC bridge, where n is twice the number of phases. The inverter can be designed as a B6C bridge. The inverter may be further configured as one or a plurality of H-bridges.

The inverter and / or the rectifier may include semiconductor switches, such as MOSFETs or IGBTs or diodes. The semiconductor switches are circuit breakers.

In the AC adaptation charging mode, the power from the electric machine can be transmitted to the energy store via a filter, in particular via a filter which is connected downstream of the electric machine (viewed from the inverter) or which is located between the electrical machine and the energy store.

In the AC adaptation charging mode, the inverter can be operated as a down-converting DC-DC converter (in short: down-converter). In particular, in the AC adaptation charging mode, the inverter may be operated as a down converter together with at least one winding of the electric machine. Further, in the AC adaptation charging mode, the inverter may be operated as a switch of a buck converter resulting from the combination of the inverter with the electric machine (and the corresponding drive). In particular, only a portion of all the power switches of the inverter are used to implement the switches of a buck converter. In this case, the down converter formed in this way can convert a DC voltage delivered by the rectifier into another, lower DC voltage. In AC direct charging mode, the inverter may be disabled. In particular, in AC direct charging mode, all the switches of the inverter are open. In the AC Adaptive Charge mode, the DC voltage resulting from rectification (and PFC filtering) is adjusted to a (lower) voltage level at the battery to avoid excessive currents due to a large voltage differential between rectified AC voltage and energy storage voltage.

The voltage delivered by the inverter or the electric machine can be filtered by means of a filter. This filter is connected downstream of the electric machine and is in particular connected to the star point or the inner phase terminals of the electrical machine (switchless).

Furthermore, a DC charging mode can be provided. In this mode, the power (which is available as DC / DC voltage) is transferred directly from a DC charging port (ie without voltage conversion) to the energy storage. Alternatively or in combination with this, a DC voltage charge charging mode may be provided, in which the power from the DC charging port via a DC-DC converter to the energy storage is transmitted. Here, the DC-DC converter may be a dedicated DC-DC converter for DC charging, or may be constituted by switches of the inverter and the electric machine. In the latter case, the power is transmitted from the DC charging port via the electric machine to the inverter and from this to the energy storage. A switch that connects the energy storage directly to the DC charging port is open in the DC charging mode and closed in the DC charging mode (which may also be referred to as a direct DC charging mode).

Finally, a driving mode or a recuperation mode can be provided, in which the energy store is connected to the electric machine via the inverter. In this case, power is transferred from the energy store via the inverter to the electric machine where it is converted by the electric machine into mechanical power (traction mode), or the power is generated based on mechanical power in the electric machine and transmitted via the inverter to the energy store. In the drive mode and in the recuperation mode, the rectifier is deactivated and in particular has open circuit breakers.

There may be regenerative modes in which power may be transferred from the electrical energy store to at least one of the charging ports, such as a first regenerative mode in which power is transferred from the energy store directly to the AC charging port via the (controllable) rectifier (with the rectifier then inverting), a second regenerative mode in which power is transferred from the energy storage via the electric machine and the inverter connected thereto and via the (controllable) rectifier to the AC charging terminal (the rectifier then being inverter and the inverter converting DC voltage), or a third regenerative mode in which Power is output from the energy storage to the DC charging port.

The rectifier can be operated in a rectifier mode in which the voltage applied to the AC charging terminal is only rectified and subjected to PFC filtering, with the rectifier performing no voltage conversion (associated with PFC filtering). In other words, then the rectifier does not up-convert, but only possibly an increase in the voltage associated with the PFC filtering, such as an increase of not more than 5%, 7%, 10% or 15%. The rectified voltage results in this mode by the effective and possibly chain AC voltage at the AC charging port and possibly by a non-essential voltage increase, which is linked to the PFC filtering. The rectifier may be configured to also operate in a rectifying voltage conversion mode in which it rectifies the voltage applied to the AC charging terminal and also performs an up-conversion that goes beyond a (non-substantial) voltage increase by PFC filtering. In order to be able to carry out an upshift (substantial, ie exceeding 5%, 7%, 10% or 15%), the rectifier has at least one energy-storing component, such as at least one capacitor or at least one inductor, as described above. In particular, the rectifier has a power factor correction function (Power Factor Correction, PFC ) on. This is realized by means of the at least one energy-storing component. The up-conversion is thus realized with components of the rectifier, which also serve to realize the power factor correction function. By switching semiconductor switches of the rectifier according to parameters such as duty cycle, switching phase, phase offset and frequency, the up-conversion and / or the power factor correction function is realized and controlled.

In one embodiment, in the AC direct charging mode, the rectifier performs up-conversion (as well as rectification and PFC filtering). The inverter is deactivated here, in particular since the power is fed directly from the rectifier to the energy store. For example, the AC direct charging mode is set when the peak-to-peak voltage at the AC charging terminal (corresponding to the square root of two times the rms value of the voltage) is not more than a predetermined margin below the voltage of the energy storage. This applies in particular to a single-phase occupancy of the AC charging connection. Further, the AC direct charge mode may be adjusted when the peak peak value of the chained voltage at the AC charging terminal (corresponding to the square root of two multiplied by the chained voltage at the AC charging terminal) is not more than a predetermined margin below the voltage of the energy storage.

Thus, for example, with a voltage of the energy storage of more than 325 V or 350 V and single-phase occupancy of the AC charging connection at a mains voltage of 230 V effective AC voltage of the AC direct charging mode can be set. Here, the rectifier also works as a boost converter (boost converter), ie performs a voltage boost, so that the output voltage from the rectifier is higher than the voltage, which in pure Rectification and pure PFC filtering would result without (substantial) up-conversion.

For example, when charging with three-phase AC power (with a 230 V AC real AC voltage or a chained AC effective voltage of approximately 400 V), corresponding to a three-phase AC charging connection, the energy storage voltage is greater than 600 V, 620 V or 650 V or even 670 V, then the AC direct charging mode is also performed, in which the rectifier performs the function of up-converting in addition to the function of rectification and power factor correction and the power directly to the energy storage (and not via the inverter / the electric machine ).

Furthermore, it can be provided that, in the AC adjustment charging mode, the rectifier does not up-convert and only rectifies and performs a PFC function. In this case, the inverter is activated and, together with at least one winding inductance of the electrical machine, performs a downward conversion. The power is fed from the rectifier via the inverter and the electric machine (in this order) to the energy storage. For example, the AC matching charging mode is set when the peak-to-peak voltage at the AC charging terminal (corresponding to the square root of two times the rms value of the voltage) is not more than a predetermined margin over the energy storage voltage. This applies in particular to a single-phase occupancy of the AC charging connection. Further, the AC direct charging mode may be adjusted when the peak peak value of the chained voltage at the AC charging terminal (corresponding to the square root of two multiplied by the chained voltage at the AC charging terminal) is not more than a predetermined margin above the energy storage voltage. Thus, for example, with an effective AC voltage of the energy storage of not more than 325 V or 350 V and single-phase occupancy of the AC charging terminal at an effective mains voltage of 230 V AC, the AC adjustment charging mode can be set. Here, the rectifier operates only as a rectifier (and PFC filter) and not as a boost converter (boost converter), i. does not perform a voltage boost (which would go beyond a voltage boost through PFC filtering). As a result, the voltage delivered by the rectifier corresponds to the voltage which results in pure rectification (including PFC filtering) without upward conversion. For example, when charging with three-phase AC power (with a 230 V star fit or a chained voltage of approximately 400 VAC), corresponding to a three-phase occupancy of the AC charging terminal, the energy storage voltage is not above 600 V, 620 V, 650 V. or 670 V, then the AC matching charging mode is also performed, in which the rectifier performs only the functions of rectification and PFC filtering, not the function of up-converting. The rectifier does not output the power directly to the energy store but via the inverter / electric machine, which reduce the voltage level. The inverter and the electric machine adjust the rectified voltage by down-converting.

Further, a vehicle electrical system with an AC charging port and a rectifier will be described. This vehicle electrical system and its components correspond in particular to the electrical system and the components which have been described by means of which the method and embodiments thereof. The rectifier is selectably connected via a switching device either directly to an electrical energy store, which corresponds to the AC direct charge mode, or is connected to the electrical energy store via an inverter and an electric machine, which corresponds to the AC adaptive charge mode. The switching device is thus set up to select two power paths (starting from the rectifier), both of which lead to the energy store. One power path is direct and the other power path is via the inverter and the electrical machine connected to it. The inverter is connected via the electrical machine with the electrical energy storage. The inverter is connected between the rectifier and the electric machine. Starting from the rectifier, the electric machine is connected downstream of the inverter. Between the energy storage and the inverter, the electric machine is switched. The inner phase terminals of the electric machine (or at least one of them) is connected to the energy storage. The outer phase terminals of the electric machine are connected to the energy storage. The star point, at least one inner phase connection or a star point-side end of at least one winding or all windings of the electrical machine is connected to the energy store.

This allows either direct charging or charging via the inverter and the inverter downstream electric machine, which together can represent a down-converting DC-DC converter (down-converter). In this case, at least one circuit breaker of the inverter forms at least one switch of the down converter, while at least one winding or a Section thereof forms an inductance of the buck converter. The inverter or at least a subset of the power switches of the inverter is designed to also be operated as a switch of a buck converter.

The rectifier is configured to rectify the AC current transferred via the AC charging port. Further, it is arranged for PFC filtering in which, in particular, the power factor of the power transferred via the AC charging port is increased and harmonics are reduced. Further, the rectifier is arranged to adjustably step up the voltage. Here, the rectifier may be formed as mentioned at the beginning as a Vienna rectifier. In particular, the rectifier is also designed to realize a power correction filter. For this purpose, the rectifier has at least one energy storage component such as a coil or a capacitor. In other words, the rectifier is equipped with a power correction filter or is at least equipped with the function of power correction filtering or changing the power factor. Elements of the power correction filter are also used to perform an up-conversion function of the rectifier. For this purpose, the rectifier in particular has at least one energy-storing element such as an inductor or a capacitor, as already mentioned. As at least one energy-storing element for forming the up-conversion function, preferably the same at least one energy-storing element is used, with which the PFC filter function of the rectifier is realized. The rectifier is configured to carry out the AC adaptation charging mode and the AC direct charging mode. More specifically, the control unit is configured together with the rectifier to execute the AC adjustment charging mode and the AC direct charging mode. The control unit is configured to set either the AC adaptation charging mode or the AC direct charging mode (or another mode).

As mentioned, the rectifier may be configured to operate as an up-converter in at least one operating mode (particularly in the AC direct-charge mode). It may be further provided that the rectifier does not work as an up-converter in AC adaptive charge mode (apart from a non significant increase in voltage by the PFC function of, for example, not more than 5%, 7%, 10% or 15%). In particular, the rectifier may include components designed to rectify a voltage of at least 50%, 100%, 150%, or 200% above the rated peak-to-peak voltage at the AC power port (if appropriate, taking into account the particular linkage factor).

The electric machine can be connected via a filter with the electrical energy storage. The filter may be connected downstream of a switch of the switching device (seen from the electrical machine). The filter is especially direct, i. switchless, connected to the electrical machine, in particular with at least one inner phase connection.

The vehicle electrical system may also have a DC charging port. This is preferably connected via at least one switch to the energy storage. The DC charging connection is not via the filter with the energy storage, which may be connected to the electrical machine (or this downstream).

The vehicle electrical system may further comprise a control device, which is also abbreviated above as control. The controller is drivingly connected to the switching device and the inverter. The control device may be multi-part and / or hierarchical and comprise a part that controls the switching device, comprise a further part that controls the inverter or its power switch, and may also have a higher-level control unit. However, the hierarchy or structure of the control device can be multifarious and will not be discussed further below. The control device is set up to control the switching device in the AC direct charging mode, to connect the AC charging connection directly to the energy store. The controller is further configured to drive the switching device to connect the AC charging port to the inverter in an AC matching charging mode. The control device is set up in this mode to control the inverter to work together with at least one winding of the electric machine as a DC-DC converter. In particular, the switching device is arranged to disable the inverter in the AC direct charging mode, i. to provide all switches of the inverter in open condition.

The controller may further be configured to openly provide both switches of the switching device in a DC charging state while a switch is provided closed, connecting the DC charging port to the Energy storage connects.

The switching device may have a first switch which connects the rectifier to the energy store. The switching device may include a second switch provided between the energy storage and a connection connecting the rectifier to the inverter. In particular, the second switch is provided between the electric machine and the energy store or connects these two components. The second switch can be provided in particular at the neutral point of the electric machine (or at its inner phase terminals) and can connect this or these to the energy store. In the AC charging modes, the first and second switches are alternately open or closed.

In an alternative embodiment, the switching device comprises only the first switch, while the second switch is realized by the switches of the inverter. In this case, the power path passing through the inverter or via the electric machine (and used for the AC adaptive charging mode for transmission) is opened or closed by the switches of the inverter itself, during the path leading directly from the rectifier to the energy storage the first switch is opened or closed. The control device is designed to alternately open or close the first switch on the one hand and the switches of the inverter on the other hand in the alternating-current charging modes. Herein, the controller may be configured to close the first switch and openly drive the switches of the inverter in the AC direct-charge mode, and open the first switch open and the switches of the inverter closed in the AC adaptive charge mode. Instead of controlling all switches of the inverter closed, a subgroup of the full bridges or even a full bridge of the inverter can be controlled closed.

The vehicle electrical system described here is designed to carry out the method. The method uses the described components of the vehicle electrical system.

The 1 shows an overview for a more detailed explanation of the vehicle electrical system or the method.

A symbolically represented vehicle electrical system BN includes an energy store IT in the form of a traction battery and an inverter I that has a first switch B1 with the energy storage IT connected is. On the opposite side is an electric machine M connected to the inverter. The electric machine M in particular has several phases and can be designed as a permanent-magnet, self-excited or externally excited electrical machine, for example as a synchronous machine, or can be an asynchronous machine.

The electric machine M has a star point SP on. This is located at the inner phase terminals of the electric machine. The star point SP can be designed separable.

Seen from the inverter I, the electric machine is a second switch S1 downstream. The second switch S1 connects the electric machine M (in particular their star point SP or at least one inner phase connection of the electrical machine EM ) With the energy storage, in particular directly, ie without changing the voltage. An optional filter F may be provided which extends between the electric machine M and the energy storage IT located, in particular between the second switch S1 and the energy storage.

An AC charging port ACLb (designed as a charging socket, for example) is via a rectifier GR with the first switch B1 and with the inverter I connected. The first switch B1 and the inverter I (Especially its DC side) are connected to the DC side of the rectifier GR connected. The AC charging port ACLb is with an AC mains ACN connected, that is located outside the vehicle electrical system and in a charging station LS can be provided. The AC mains ACN includes an AC power source. The rectifier GR has the function of a power factor correction filter (in addition to the function of rectification), so that the power factor at the AC charging port ACLb prevails, adjusted and in particular (compared to the use of a rectifier without PFC function) can be increased.

Is the first switch B1 closed and the second switch S2 open, then the rectifier GR directly connected to the energy storage ES. This corresponds to the AC direct charging mode. Is the first switch B1 open and the second switch S2 closed, then the rectifier GR over the inverter I and the electric machine M (in this order) with the energy storage IT connected. Here, the inverter is operated together with the electric machine as mentioned above as (in particular down-converting) DC-DC converter. The optional filter F allows the suppression of switching pulses in the electrical system BN caused by switching processes in the inverter I be generated in the operation as (switch unit of) a DC-DC converter.

A ground switch B2 connects the energy storage switchable with a negative supply potential of the vehicle electrical system. The aforementioned switches B1 and S2 as well as a switch B3 are provided in a positive supply potential rail. A battery disconnect switch B3 is between the filter and the energy storage IT intended. The switches B2 and B3 are closed in the AC charging modes and can be provided open in case of failure or inactive electrical system.

An optional DC charging port DCLB allows the connection of the vehicle electrical system BN to a DC network DCN outside the vehicle electrical system BN lies. The DC network DCN can be part of the charging station LS his. The DC charging connection DCLB is via a DC voltage switch S2 (and over the switch B3 ) connected to the energy storage. The connection between the switch S2 and the energy storage IT is direct, ie without voltage transformer. However, it may be for voltage level adjustment the DC charging port DCLB be followed by a DC-DC converter. An alternative (or additional) connection between the DC charging port DCLB and the energy storage IT leads through a switch C1 , The switch switch C1 connects the DC charging port DCLB with the energy storage IT , If this is closed, power can be directly from the DC charging port DCLB to the energy storage IT be transmitted.

An abstracted control device CT is driving with the switches B1 and S1 connected. The control device CT controls as mentioned in the AC charging modes, the switches B1 and S1 alternatively. That's why the switches form B1 and S1 (by the alternate control) a switching device. The control device CT is also driving with the switches S2 . B3 and C1 connected (if present), which are closed during DC charging while the switches S1 . B1 are open. The control device CT is also driving with the switches S2 and B3 or. C1 connected to this unlike the switches B1 and S1 to drive closed when a DC charging mode is present. The controller may further driving with the rectifier GR and with the inverter I be connected. If no switch S1 is provided, instead of this switch, the switch of the inverter I be opened or closed by the controller, such as when switching between the AC charging modes. The control device CT is due to the driving connection with the rectifier GR set to set a power factor of the rectifier at the AC charging port ACLb prevails, and harmonics to filter or mitigate. As mentioned, the controller CT be formed in several parts or hierarchical. The control device CT may further comprise an input for inputting a desired operating mode. The controller may be further configured to execute the traction mode or recuperation mode, as described above.

Optional or alternative components and connections are shown dashed, dotted or dash-dotted.

Claims (12)

Method for transmitting electrical power to an electrical energy store (ES) of a vehicle electrical system (BN), wherein in an AC direct charging mode, the power directly from a rectifier (GR) of the vehicle electrical system (BN), which is fed by an AC charging connection (ACLB) is transferred to the energy storage (ES) of the vehicle electrical system (ES) and in an AC adapter charging mode, the power from the rectifier (GR) via an inverter (I) and from the inverter (I) via an electrical machine (EM) to the energy storage (ES) is transmitted. Method according to Claim 1 in the AC direct charging mode, a switching device (B1, S1) connects the rectifier (GR) to the energy store (ES) and in the AC adapter charging mode the switching device (B1, S1) connects the rectifier (GR) to the inverter (I) combines. Method according to Claim 1 or 2 wherein the rectifier (GR) rectifies the power in at least one of the AC charging modes and performs a power factor correction filter function and / or performs up-conversion in the AC direct charging mode. Method according to one of the preceding claims, wherein in the AC adjustment charging mode, the power from the electric machine (EM) via a filter (F) to the energy storage (ES) is transmitted. Method according to one of the preceding claims, wherein in the AC adjustment charging mode, the inverter (I) is operated as a DC-DC converter and converts a DC voltage output by the rectifier (GR) into a lower DC voltage. Method according to one of the preceding claims, wherein in one DC Charge Mode, the power is transferred from a DC charging port (DCLB) directly to the energy storage (ES). Vehicle electrical system with an AC charging connection (ACLB) and a rectifier (GR), wherein the rectifier (RG) via a switching device (B1, S1) selectable either directly to an electrical energy storage (ES) is connected via an inverter (I) and an electrical Machine (EM) with the electrical energy storage (ES) is connected, wherein the inverter (I) via the electric machine (EM) to the electrical energy storage (ES) is connected. Vehicle electrical system to Claim 7 wherein the rectifier (GR) is configured to rectify the AC current transferred via the AC charging terminal (ACLB) and as a power factor correction filter for the power transmitted via the AC charging terminal (ACLB). Vehicle electrical system to Claim 7 or 8th , wherein the electric machine is connected via a filter with the electrical energy storage (ES). Vehicle electrical system according to one of Claims 7 - 9 , which further comprises a DC charging connection (DCLB), which is connected via a switch (S2; B3; C1) to the energy store (ES). Vehicle electrical system according to one of Claims 7 - 10 further comprising a controller (CT) drivingly connected to the switching device (B1, S1) and the inverter (I), the controller (CT) being arranged to operate the switching device (B1, S2) in an AC direct-charging mode to connect the AC charging port (ACLB) directly to the energy storage (ES), and the controller (CT) is further configured to drive the switching device (B1, S2) in an AC matching charging mode, the AC charging port (ACLB) to the inverter (FIG. I) and to drive the inverter (I) to work together with at least one winding of the electric machine (M) as a DC-DC converter and in particular as a buck converter. Vehicle electrical system according to one of Claims 7 - 11 wherein the rectifier (GR) is arranged to operate as an up-converter in at least one operating mode.

Images