DE102017200904A1 - Power control device for an electrical machine and method for separating an electric machine from an electrical energy storage - Google Patents

Abstract

A vehicle powertrain having a power driver (LS) includes an electric machine (EM). The power driving device (LS) has a DC voltage terminal (GA) and an inverter (IN) including a semiconductor bridge circuit (11-23; H1-H24) controlled by a controller. The semiconductor bridge circuit (11-23; H1, H11, H21) has a first semiconductor switch (11-13; H1, H11, H21). The power drive device further comprises at least one second semiconductor switch (S1; H3, H13, H23) connected in antiseries to the at least one first semiconductor switch (11-13; H1-H21). The controller (C1, C2) has a separation signal input (TES, TEM) for receiving a separation signal. The controller (C1, C2) is arranged to open the first and second semiconductor switches when the disconnect signal occurs, the disconnect signal representing a normal operation mode of the electric machine (EM) in which the electric machine (EM) is torqueless.Further a powertrain is described in which the separation signal represents an error in the transmission of electrical energy between the connection interface (AS) or the stationary component (L) on the one hand and the energy storage on the other hand.

Description

It is known to equip a vehicle with an electric drive, wherein an electrical energy store in the form of a rechargeable battery supplies the energy for operating the electric drive. To drive a vehicle relatively high power levels are required, so that the drive must be designed according to this power. In order to reduce the conductor diameter and the current to be controlled with the same (high) power, relatively high operating voltages for electric drives and their energy storage are used. For example, voltage levels of more than 300 volts may occur here, in particular more than 350 volts, for example 400 volts or even 600 volts or 800 volts.

Since these high voltages pose a high safety risk, care must be taken that the contact voltage is harmless, for example during maintenance or in the case of an accident. To achieve this, contactors are usually used, that is, electromechanical switches, which separate the energy storage from the rest of the vehicle electrical system.

Such electromechanical switches must be designed for high holding currents (corresponding to the maximum traction power) and, in particular, for high switching powers in order to switch reliably in order to interrupt the flow of current. This is associated with high costs, even if the switching events are rare and limited to maintenance or accident.

It is an object of the invention to indicate a possibility with which, in particular, the cost for the realization of a reliable separation process can be reduced.

This object is achieved by the vehicle powertrain and by the method according to the independent claims. Further embodiments, features, properties and advantages will become apparent from the description and the attached figures.

It is proposed to use for the separation of the electrical energy storage semiconductor switches, which already perform functions of an inverter and / or a DC-DC converter. As a result, at least one potential of the energy store can be disconnected without the need for an electromechanical disconnecting switch (for separating this potential). It can be saved at least one of the two circuit breakers (one disconnector per potential of the energy storage). In order to prevent a current flow in both directions (with respect to the energy storage), two semiconductor switches are opened, which are arranged antiserially to each other when an error signal is present. Both semiconductor switches are part of an inverter or part of an inverter and a DC-DC converter. The two semiconductor switches (i.e., the first and second semiconductor switches) antiserially (directly or indirectly) between an AC terminal and a DC terminal of the power control device. In a current path leading from the AC terminal to the DC terminal, the two semiconductor switches (i.e., the first and second semiconductor switches) are sequentially switched and antiseries to each other. In other words, the operating directions of the first and second semiconductor switches, in which they are controllable by external signals, are opposite to one another, the working directions being viewed in a current path leading from the AC connection to the DC connection.

Both (ie the at least one first and the at least one second) of the anti-serially connected semiconductor switch may be part of the bridge circuit of an inverter, or one of these two semiconductor switches (namely the at least one first semiconductor switch) may be part of the bridge circuit of the inverter, and at least one other semiconductor switch (namely, the second) may be part of a DC-DC converter. Such a DC-DC converter can be connected approximately between the energy store and the inverter, for example to bring the operating voltage of the inverter to a desired level or to keep constant.

A power driving apparatus for an electric machine will be described. In particular, this relates to a power control device in a vehicle electrical system. The electric machine may be an electric machine of a traction drive, a starter generator or other component, such as an electric air conditioning compressor. The power drive device has a DC voltage terminal and an inverter. The inverter is provided between the DC voltage terminal and an AC terminal of the power driving device. The AC voltage connection is intended for connection of the electrical machine. The power driving device is provided for an electric machine such that the power driving device has an inverter capable of outputting (or also picking up) three-phase current at the AC power terminal. The inverter has a semiconductor bridge circuit. The inverter is unidirectional or bidirectional and is in particular arranged, from DC voltage, at the DC voltage connection or at a DC voltage side of the inverter is applied to generate an AC voltage, in particular a three-phase current, at the AC voltage terminal. For this purpose, the individual semiconductor switches of the semiconductor bridge circuit are selectively controlled in a known manner.

The electric machine is in particular a permanently excited machine. In this type of electric machine, there is a problem of induction of voltage when the electric machine is moved from outside, such as in a towing operation. This problem, in particular the problem of the electromotive force when driving the electric machine, which should not exceed the maximum voltage of the power electronics, is solved by the opening of the relevant switch described here. The electric machine may further be a synchronous machine or asynchronous machine. As mentioned, the electric machine can be a permanently excited machine or a separately excited machine.

In particular, an electrical machine with an increased reluctance can be used. Such motors have magnets which are buried in the rotor of the electric machine, which are buried in a V-shape, or which are arranged radially and buried. It results over motors of the same type and size, but do not have the buried as described magnets, a higher reluctance.

The power drive device includes at least one controller. This is drivingly connected to the semiconductor bridge circuit, in particular with their semiconductor switches. The controller has a disconnect signal input to which a disconnect signal may be received, the controller configured to open the at least one first and the at least one second semiconductor switch upon receiving a disconnect signal. The controller (or other controller), along with the semiconductor bridge circuit, is configured to convert a DC voltage at the DC voltage terminal into a three-phase current for delivery to the AC voltage terminal. The inverter can be connected directly to the DC voltage connection, that is to say without the change in the voltage level, or the inverter can be connected to the DC voltage connection indirectly, in particular via a DC-DC converter. The controller is preferably configured to drive the semiconductor bridge circuit to convert a DC voltage at the DC voltage terminal into a three-phase current for delivery to the AC voltage terminal. However, this function can also be implemented in another controller, which is preferably connected to the controller for opening semiconductor switches when a disconnect signal occurs, or via a common control unit (control unit).

The semiconductor bridge circuit has at least one first semiconductor switch, which is connected between the AC voltage terminal and a first potential of the DC voltage terminal. In other words, the at least one first semiconductor switch is connected between the AC voltage terminal and a potential rail having the first potential. At least one second semiconductor switch of the power drive device is connected in antiseries to the at least one first semiconductor switch. The first and the second semiconductor switches are connected in parallel succession between the DC voltage connection and the AC voltage connection (directly or indirectly via a further component, for example via an inductance). The at least one second semiconductor switch is connected to the first potential (that is, to a first potential rail) of the DC voltage terminal. The at least one first and the at least one second semiconductor switch are provided in series between the DC voltage terminal and the AC voltage terminal.

The controller has a disconnect signal input. This is set up to receive a disconnect signal. The isolation signal corresponds to a normal operation mode of the electric machine in which the electric machine is torque-free. The isolating signal thus corresponds to a normal operating mode of the electric machine in which the electric machine is de-energized (in which this relates in particular to the active component). Both definitions are directly linked and therefore interchangeable.

This is the case, for example, when the vehicle is being towed (in general: being moved while the drive train is inactive) or when electric power is being transmitted through the electric machine, such as during charging or regeneration. This is also the case in which the vehicle is driven by internal combustion engines and the electric machine is inactive with respect to the drive, corresponding to a state of "pure internal combustion engine drive" of the drive train. This also corresponds to a normal operation mode.

In the normal operation mode, the drive train is in a state where the electric machine is in motion or can be set in motion (both without generating movement by the electric machine itself) or in which an electric power supply through the engine ends is. The (finished) supply of electrical power in this case relates to an energy transfer without generating torque (ie, feeding or charging through the electric machine).

In particular, the isolation signal corresponds to an operating mode in which the electric machine is mechanically driven, i. is set in rotation by mechanical power (but without transmission of torque and without delivery or supply of electrical power from or to the electric machine). The isolation signal corresponds to an operating mode in which the electric machine is mechanically driven, i. is mechanically in rotation by supplied mechanical power or by an external movement, or in that it is possible that the electric machine by supplied mechanical power (without significant torque transmission) is set in motion or will. For example, these are operation modes that correspond to towing (with the electric machine being in rotation by the towing motion), to pure-combustion engine driving, or to parking, and in a towing operation (from parking), the electric machine is set in motion by supplying mechanical power. In other words, the separation signal corresponds to an operating mode in which the electric machine is connected to the output of the vehicle in a motion-transmitting manner, for example a coupled state of the drive train section between electric machine and output, but in particular without transmission of mechanical or electrical power to or from the electric Machine.

The isolation signal may thus reflect a towing mode of the vehicle powertrain. In this, the electric machine is mechanically driven or moved substantially without torque. Alternatively, the isolation signal may reflect a park mode in which the vehicle is parked. The disconnect signal is output in park mode when a movement of the vehicle is detected while the drive is inactive. This movement can be detected by a wheel sensor, by a motion sensor, by a tilt sensor, and / or by rotary encoders of the electrical machine, wherein a plurality of sensors can be used to validate the state of motion or redundant. Further, the isolation signal may reflect a pure combustion engine driving state in which the electric machine is passively moved. For example, from a drive mode controller, a corresponding signal representing the driving condition may be output, and components of the internal combustion engine driver may also output a corresponding activity signal representing the driving condition, or a rotary encoder or speed detection may be moving in the pure engine driving condition in the sense of the disconnecting signal play.

The vehicle drive train may include an electrical energy storage and a connection interface (such as a charging socket or an inductive charging interface). The connection interface is designed to transmit electrical energy between the energy store and a stationary component. The connection interface is connected to the power drive device via the electric machine. The isolation signal may reflect a properly terminated power transfer between the port interface or the stationary component, on the one hand, and the energy storage, on the other hand. The isolation signal represents the separation of the energy storage from the stationary component.

• Rückspeisen beendet, etwa wenn eine vorgegebene, übertragene Energiemenge oder eine vorgegebene, im Energiespeicher verbleibende Energiemenge oder eine vorgegebene Rückspeisezeitdauer erreicht wurde oder eine Aktivierung des Antriebsstrangs erfasst wurde oder eine Temperaturschwelle (insbesondere des Energiespeichers oder einer Rückspeisevorrichtung) überschritten wurde; und/oder
• Laden des Energiespeichers beendet, etwa wenn eine vorgegebene, übertragene Energiemenge oder eine vorgegebene, im Energiespeicher verbleibende Energiemenge oder eine vorgegebene Rückspeisezeitdauer erreicht wurde oder eine Aktivierung des Antriebsstrangs erfasst wurde oder eine Temperaturschwelle (insbesondere des Energiespeichers oder einer Ladevorrichtung) überschritten wurde;
• Die vorangehenden Merkmale und Ausführungsformen betreffen den Fall, dass das Trennsignal einem Normalbetrieb-Modus der elektrischen Maschine entspricht, in dem die elektrische Maschine drehmomentlos (oder stromlos) ist. Davon abweichend kann jedoch auch das das Trennsignal einem Fehler bei der Übertragung von elektrischer Leistung im Rahmen eines Lade- oder Rückspeisungsprozesses entsprechen, bei dem die Leistung durch die elektrische Maschine geleitet wird. Mit anderen Worten kann das Trennsignal einem Fehler bei der Übertragung von Leistung zwischen der Anschlussschnittstelle oder der stationären Komponente einerseits und dem Energiespeicher andererseits entsprechen. Hierbei hat der Antriebsstrang eine Anschlussschnittstelle (zum Laden oder Rückspeisen), die über die elektrische Maschine (sowie über die Leistungsansteuervorrichtung und gegebenenfalls einem weiteren Wandler) mit dem elektrischen Energiespeicher des Antriebsstrangs verbunden ist. Wie in der oben genannten Ausführungsform, in der das Fehlersignal das ordnungsgemäß Beenden einer Energieübertragung von oder zum Energiespeicher wiedergibt, betrifft dies das Beenden der Energieübertragung von oder zum Energiespeicher. Im Unterscheid zur oben genannten Ausführungsform wird hierbei das Trennsignal nicht innerhalb des Normbetriebs verwendet, sondern als Signal eines Fehlers beim Übertragen von Leistung von oder zum Energiespeicher sowie über die elektrische Maschine hinweg. Die Übertragung von Energie durch die elektrische Maschine hindurch, d.h. durch mindestens eine Wicklung der elektrischen Maschine, dient zur Filterung des übertragenen Stroms, insbesondere zum Tiefpassfiltern mittels der Induktivität der elektrischen Maschine.

The disconnect signal can be emitted at the following events: _

• Regenerations terminated, such as when a predetermined amount of transmitted energy or a predetermined amount of energy remaining in the energy storage or a predetermined Rückspeisezeitdauer has been reached or activation of the drive train has been detected or a temperature threshold (in particular the energy storage or a regenerative device) has been exceeded; and or
• Charging the energy storage stops, such as when a predetermined amount of transmitted energy or a predetermined amount of energy remaining in the energy storage or a predetermined Rückspeisezeitdauer has been reached or activation of the drive train has been detected or a temperature threshold (in particular of the energy storage or a charging device) has been exceeded;
• The foregoing features and embodiments relate to the case where the disconnect signal corresponds to a normal operation mode of the electric machine in which the electric machine is torque-free (or de-energized). Deviating from this, however, the disconnecting signal may also correspond to an error in the transmission of electric power in the context of a charging or regenerative process in which the power is passed through the electric machine. In other words, the isolation signal may correspond to an error in the transmission of power between the port interface or the stationary component, on the one hand, and the energy storage, on the other hand. In this case, the drive train has a connection interface (for charging or regeneration), via the electrical machine (as well as the power drive device and possibly a another converter) is connected to the electrical energy storage of the drive train. As in the above-mentioned embodiment, in which the error signal reflects the proper termination of an energy transfer from or to the energy store, this relates to the termination of the energy transfer from or to the energy store. In contrast to the above embodiment, in this case the isolation signal is not used within normal operation, but as a signal of an error when transmitting power from or to the energy storage and across the electrical machine. The transmission of energy through the electrical machine through, ie by at least one winding of the electric machine, is used for filtering the transmitted current, in particular for low-pass filtering by means of the inductance of the electric machine.

Thus, a vehicle powertrain having a power drive device and an electric machine is also described, wherein the power drive device is equipped with a DC voltage terminal and an inverter. The inverter is connected between the DC voltage connection and the electrical machine or an AC connection for connecting the electrical machine. The inverter includes a semiconductor bridge circuit. The power drive device includes a controller that is drivingly connected to the semiconductor bridge circuit. The semiconductor bridge circuit has at least one first semiconductor switch. This is provided between the AC voltage terminal and a first potential of the DC voltage terminal. The power drive device further comprises at least one second semiconductor switch which is antiserially connected to the at least one first semiconductor switch and which is further connected to the first potential of the DC voltage terminal.

The controller has a disconnect signal input configured to receive a disconnect signal. The controller is configured to open the at least one first semiconductor switch and the at least one second semiconductor switch when the isolation signal occurs. The vehicle drive train has an electrical energy store and a connection interface. This is set up for the transmission of electrical energy between the energy store and a stationary component. The connection interface is connected to the power drive device via the electric machine. The isolation signal reflects an error in the transmission of electrical energy between the connection interface or the stationary component on the one hand and the energy storage on the other. Such an error may be the failure of a component, or the exceeding of an operating parameter limit, such as exceeding a maximum current, a maximum voltage or a maximum temperature. In particular, these maximum values are not the upper limits of a permissible operating range but lie around a predetermined minimum margin above these upper limits and indicate the occurrence of an error.

The controller is configured to open the at least one first semiconductor switch and the at least one second semiconductor switch when the isolation signal occurs. The separation signal can be reproduced, for example, by a certain level or by a specific signal sequence. The controller may be composed of one or more individual controls, each controller having such a separator signal input. In particular, if the at least one first semiconductor switch is provided in a different bridge circuit or on a different component than the at least one second semiconductor switch, then a plurality of control elements may be present (preferably one per component), which each have a corresponding isolating signal input. In addition, a higher-level control unit may be provided, to which the control or the control units are or are arranged downstream.

A first possibility is that the at least one first semiconductor switch and the at least one second semiconductor switch are provided in the same component (and in particular are set up to realize a function together). Therefore, the at least one first semiconductor switch and the at least one second semiconductor switch may be part of the semiconductor bridge circuit or each part of the inverter. The semiconductor bridge circuit therefore has at least two semiconductor switches, which are connected in antiseries to one another between the AC voltage connection and the DC voltage connection. The semiconductor switches are in particular switchable by external signals. The semiconductor switches are in particular configured to control (in particular to switch) current in a flow direction in accordance with a signal at a control input. Furthermore, the semiconductor switch may not be able to control the current flow in accordance with an external control signal in an opposite current flow direction, in particular if the semiconductor switch has inverse diodes or body diodes which bridge the relevant switching element counter to the direction of flow (in controllable operation). This is the case, for example, with field-effect transistors such as MOSFETs and IGBTs. As a semiconductor switch of the power drive device mentioned here (and the method mentioned here) are thus preferably field effect transistors such as MOSFETs or IGBTs. In order to prevent a current flow in both directions, it is provided that at least one first and at least one second semiconductor switch is provided, which are connected in series, but in their working direction (in which a control of the current flow is possible by means of external signals) are opposite to each other , In other words, the direction of the source-drain or the direction of the collector-emitter of the first and the second semiconductor switch may be opposite to each other. Such an antiserial series circuit relates to the view of a current flow between AC voltage terminal and DC voltage terminal.

The semiconductor bridge circuit is in particular an H-bridge circuit. The at least one first semiconductor switch and the at least one second semiconductor switch are part of this H-bridge circuit. In this way, only one control can be provided, namely that which controls the semiconductor switches of the H-bridge circuit, and which further comprises a separation signal input as described herein. As a result, the at least one first and the at least one second semiconductor switch receive a further function, namely the function of disconnecting the electrical machine from the energy store or from the DC voltage connection, in addition to the usual function of the inverter, from the DC voltage at the DC voltage connection to a three-phase current at the AC voltage connection produce.

An H-bridge circuit comprises two series circuits or branches for each phase of the AC voltage connection. Each series circuit comprises two semiconductor switches connected in series with one another, which extend in particular between the two supply potentials of the DC voltage connection (for example ground and a positive supply potential). The at least one first semiconductor switch and the at least one second semiconductor switch belong to the same phase and in this case are assigned to different series circuits (of the same phase). The first and the second semiconductor switch are connected to the same supply potential, in particular to the positive supply potential of the inverter.

The AC voltage terminal has a plurality of phases, each phase being connected to a connection point between two series-connected semiconductor switches. The H-bridge circuit comprises a full-bridge circuit for each phase, the bridge between the two branches (which are each provided by two series-connected semiconductor switches) each formed by an inductance. One of the two branches is connected to the DC voltage connection (directly or indirectly via a DC-DC converter), while the other series connection of the same phase is connected to one phase of the AC voltage connection (or the electrical machine). In particular, the first and the second semiconductor switch are connected in series here for one phase, for several phases or for all phases, in particular via the inductor or via the bridge, which connects the two branches of the H bridge circuit.

Another possibility is that the at least one first semiconductor switch is part of the inverter or the semiconductor bridge circuit, and the at least one second semiconductor switch of another component (and in particular another function) belongs, and for example part of a DC-DC converter. Therefore, the power drive device may comprise a further component, in particular in the form of a DC-DC converter, wherein this component is connected in series between the DC voltage input (for connection of the energy storage device) and the inverter. The DC-DC converter or this component has semiconductor switches, of which at least one forms the second semiconductor switch. In other words, the at least one second semiconductor switch is part of the DC-DC converter or this component. The first semiconductor switch is part of the semiconductor bridge circuit or part of the inverter. The DC-DC converter is in particular a synchronous converter with two series-connected semiconductor switches. The ends of the series circuit formed in this way are connected to the inverter or to its DC side.

The DC-DC converter also has an energy store, for example in the form of an inductance or a capacitor. In particular, an inductance of the DC-DC converter between the first potential or the DC voltage terminal of the power drive device and the node of the two semiconductor switches may be connected, which are connected in series as mentioned. There may be provided a controller which drives both the component or the DC-DC converter and the inverter, and further comprising a separation signal input. Such a controller is set up to open both at least one first and the at least one second semiconductor switch when a disconnect signal or an error signal is received. Furthermore, a first controller may be provided, which drives the semiconductor switches or the bridge circuit of the inverter, and it may be provided a second control, which are the semiconductor switches of the DC-DC converter or the component controls. Both controllers preferably each have a separation signal input. Both controllers are set up to open the respective semiconductor switches upon receipt of a disconnect signal or an error signal. The first component is configured to open the at least one first semiconductor switch when a disconnect signal is received. The second controller is configured to open the at least one second semiconductor switch when a disconnect signal is received.

Finally, a higher-level control unit may be provided, as well as a first and a second controller, wherein the first controller controls the semiconductor switches of the component or the DC-DC converter and the second controller controls the semiconductor switches of the inverter or its bridge circuit. The first and the second controller are connected downstream of the higher-level control unit. The higher-level control unit can have a separation signal input. The higher-level controller is drivingly connected to the first and the second controller. The first and the second controller and the higher-order control unit are set up to receive the at least one first semiconductor switch and the at least one second semiconductor switch upon receipt of an error signal or separation signal (in particular at the isolating signal input of the higher-order control unit).

The semiconductor bridge circuit (of the inverter) may be a fully controlled three-phase bridge circuit. In this case, it is provided for each phase that two semiconductor switches are connected in series and are connected to the DC voltage connection. The AC voltage terminals correspond to the connection points between the semiconductor switches. In particular, the semiconductor bridge circuit is a B6C pressure or generally a BnC bridge, where n represents the number of phases multiplied by two. The capital letter C in this abbreviation again states that the switching elements of the bridge circuit can be controlled by external signals. Again, the semiconductor switches are preferably field effect transistors such as MOSFETs or IGBTs. The at least one first semiconductor switch is connected between the DC-DC converter and the AC voltage connection. The at least one first semiconductor switch is thus a switch of the series connection of two switches, which constitutes a branch or a phase of the full-bridge circuit. The at least one second semiconductor switch is a part of the DC-DC converter or a component which is connected between the semiconductor bridge circuit of the inverter and the DC voltage connection. In particular, the at least one second semiconductor switch is connected to the first potential via the memory element (of the DC-DC converter which forms the component). The memory element is in particular an inductance, via which the semiconductor switches of the DC-DC converter are connected to the first potential.

The first potential is in particular the positive potential of the energy store (which feeds the inverter). In particular, the mass can be used as the second potential of the DC voltage connection. It may be provided that there is an interruption between an electromechanical or other element between the ground connection of the energy store and the inverter (in particular between the energy store connection and the DC-DC converter, if present). It can be provided that at least one of the controls or the higher-level control unit opens this disconnect switch in the second potential (the ground terminal of the energy store downstream) upon receipt of a corresponding disconnect signal or error signal, preferably simultaneously with the opening of the first and second semiconductor elements. The energy store is preferably a high-voltage energy store with an operating voltage of more than 60 volts, in particular more than 120 volts and preferably more than 300 or 360 volts. For example, the operating voltage of the energy storage 400 volts, 600 volts or even 800 volts. The energy store is, for example, a lithium-based battery with several series-connected galvanic cells (based on lithium technology). The energy storage is in particular a traction storage of the vehicle electrical system.

The controller, the controllers or the higher-order control unit can furthermore be designed to permanently open the at least one first and the at least one second semiconductor switch, in particular until a reset signal is present. Further, these control elements of the power drive device may be configured to drive the at least one first and the at least one second semiconductor switch with an open state after a disconnect signal has occurred, in particular until a reset signal is received.

The isolation signal may be provided by a body controller, by the aforementioned sensors, by a controller (such as in the form of normal operation), by a safety device, or generally by a signal processing component that is set up, a maintenance condition, a towing condition , a state of purely internal combustion engine driving (with passively moving electric machine), a state of charge, a regenerative state or a Detect fault state of the charging or regenerative and / or is adapted to detect the beginning of a towing process or the end of a regeneration or charging or a fault in the context of feedback or charging.

It can be provided (or more) control, which drives the semiconductor switch of the inverter for converting AC voltage into DC voltage and / or the semiconductor switch of the DC-DC converter for converting DC voltage into DC voltage (other height). At least one further control may be provided, which activates the at least one first and / or the at least one second semiconductor switch for opening when a disconnection signal has been received. However, it can also be provided that the at least one controller, which controls the function of the conversion, also opens the first and / or second semiconductor switch when a disconnection signal is received. While the semiconductor switches to be opened upon receipt of a disconnect signal are part of the inverter and possibly also part of a DC-DC converter, it may be provided that the respective controllers are separated with respect to these functions (converting and disconnecting).

As mentioned, the at least one first semiconductor switch and the at least one second semiconductor switch are transistors which have a body diode or inverse diode. This is due in particular to field effect transistors by the structure of the semiconductor switch. It may further be provided that a diode is connected as a discrete component antiparallel to a semiconductor switch. In this case, as well as in the case of inverse diodes, it is possible for current to flow in the opposite direction to the working direction or the usual forward direction of the semiconductor switch, in particular independently of an external triggering. In order to prevent current from flowing counter to the working direction, the first and the second semiconductor switches are connected in antiseries to one another (viewed from the DC connection in the direction of the AC connection).

The connection interface can be connected to the power drive device only or directly via the electrical machine. As a direct connection or as a connection only via the electrical machine, a connection is referred to, which does not comprise a mains connection circuit and in particular no separation or configuration switch. Nevertheless, an overcurrent or overvoltage fuse (which should not be considered a circuit breaker here) may include a filter or the like. Alternatively, the connection interface can be connected to the connection interface via the electrical machine and via a network connection circuit. In this case, a network connection circuit is provided between the connection interface and the electrical machine. This is arranged to change and / or resolve the configuration of the electric machine under control, or is arranged to disconnect and reconnect the electric machine under control of the connection interface, or both. The power connection circuit may for this purpose have switches which are individually connected to ends of the windings of the electrical machine. The power connection circuit may further include disconnect switches for controllably connecting or disconnecting the ends of the windings, and may optionally include switches for controlling the connection of the electrical machine to the connection interface.

Furthermore, a method for separating an electric machine from an electrical energy store is described. First, a disconnect signal representing a normal operation mode of the electric machine (EM) in which the electric machine (EM) is torqueless is detected. When detected, at least one first semiconductor switch and at least one second semiconductor switch are opened. These are antiparallel to each other. The semiconductor switches are provided between the electrical machine or its AC connection and a DC voltage connection, in particular a first potential of the DC voltage connection. As mentioned, the DC voltage terminal and the AC voltage terminal are preferably terminals of a power driving device provided between the power storage and the electric machine for controlling the power supply from the battery to the electric machine. The at least one first semiconductor switch is part of an inverter which is connected between the electrical energy store (or the DC voltage connection) and the electrical machine (or the AC voltage connection). Likewise, the at least one second semiconductor may also be part of an inverter. Alternatively, the second semiconductor switch is part of another component which is provided between the energy store and the electrical machine, in particular a DC-DC converter. The method preferably uses the components of the power drive device.

In particular, the separation signal represents a towing mode of the vehicle drive train. In a detected towing the separation signal (from a corresponding detection device) is emitted. The towing operation is detected in particular by detecting a movement of a component of the drive train or a power take-off, in particular when the drive train is inactive (or when it is detected that a towing operation takes place and it is detected that the Powertrain is inactive). The electric machine is disconnected (by opening the at least one switch) while it is mechanically driven, such as during the towing process. Further, the disconnect signal may reflect a park mode in which the vehicle is parked (and may be towable, particularly while the electric machine is coupled to the output). Here, the electric machine is disconnected when the vehicle is turned off or already parked. The separation comprises, as mentioned, the opening of the at least one first and the at least one second switch. The disconnection relates to the electrical disconnection of the electric machine.

Furthermore, it can be provided that the electrical machine is disconnected during a charging or regenerative process. The electric machine is disconnected while electrical energy is transferred via the electric machine between an electric energy storage and a stationary component, and thereby stops transmitting the energy. The separation signal indicates a properly terminated or terminated energy transfer between the stationary component on the one hand and the energy storage on the other hand again. In particular, the isolation signal represents an end of a charge phase of the energy store or else the end of a regeneration phase.

Rather than the disconnect signal indicating the proper end of a charge, regenerative, or toggle operation, this may also indicate the occurrence of a non-standard charge or regenerate fault, as well as the need to disconnect due to the fault or the at least one semiconductor switch to open.

It is thus further described a method for separating an electrical machine from an electrical energy storage. A disconnect signal is detected, wherein the disconnect signal represents an error in the transmission of electrical energy through the electrical machine and between a stationary component and the energy store. At least one first semiconductor switch and at least one second semiconductor switch is opened, which is connected in anti-parallel to the first semiconductor switch. The semiconductor switches are present between the electrical machine and a first potential of a DC voltage connection. At least one of the opened first and second semiconductor switches is part of an inverter. The inverter is connected between the electrical energy storage and the electric machine.

When opening the first and the second semiconductor switch, preferably two semiconductor switches are opened, which are part of a semiconductor bridge circuit of the inverter. The opening of the first and second semiconductor switches is therefore implemented by opening at least a first and at least one second semiconductor switch of the semiconductor bridge circuit of the inverter. In this case, the at least one first and the at least one second semiconductor switch are part of the inverter. In other words, as a first and second semiconductor switch two mutually antiparallel semiconductor switches are opened, which are part of the inverter. The inverter in this case comprises in particular an H-bridge. Further, the first and second semiconductor switches are connected to the same (DC) potential.

Alternatively, the opening of the at least one first semiconductor switch may include: opening at least one semiconductor switch which is part of a semiconductor bridge circuit of the inverter. In this regard, this corresponds to the method mentioned above. The opening of the at least one second semiconductor switch, however, comprises opening at least one semiconductor switch which is part of a DC-DC converter. The DC-DC converter is in this case connected between the energy storage and the inverter. In other words, a semiconductor switch of the inverter is opened as the first semiconductor switch, and as a second semiconductor switch is a semiconductor switch of the DC-DC converter. The signs of the supply potentials to which the first and second semiconductor switches are connected are identical. Preferably, all of the semiconductor switches of the inverter are opened as (multiple) first semiconductor switches connected to the same supply potential (i.e., to a supply potential of the same sign as the supply potential to which the second semiconductor switch is connected).

During the operation of the DC-DC converter for the conversion of DC voltage that semiconductor switch is repeatedly opened and closed, which is opened (permanently) even when the separation signal.

The opening of the respective semiconductor switch after receiving or due to the separation signal relates to an opening phase which is significantly longer than the opening phase of a semiconductor switch during operation of the DC-DC converter. In particular, after receiving a disconnection signal, the open state of the at least one first and the at least one second semiconductor switch lasts until a reset signal is present. Instead, the opening may be hysteresis-free with respect to the isolation signal, so that the respective switches be closed again when the isolation signal is not detected (more).

The at least one first semiconductor switch and / or the at least one second semiconductor switch may be part of the semiconductor bridge circuit.

The semiconductor bridge circuit may be an H-bridge circuit. The one semiconductor switch and / or the at least one second semiconductor switch may be part of the H bridge circuit.

The H-bridge circuit may have two series circuits each having two series-connected semiconductor switches for each phase of the AC voltage connection. The at least one first semiconductor switch and / or the at least one second semiconductor switch may belong to the same phase and different series circuits.

The power drive device may include a DC-DC converter. About the DC voltage connection can be connected to the inverter. The at least one first semiconductor switch may be part of the semiconductor bridge circuit. The at least one second semiconductor switch may be part of the DC-DC converter.

The DC-DC converter may include a memory element and at least one semiconductor switch. This can be connected between the memory element and the inverter. This can form the at least one semiconductor switch and the at least one second semiconductor switch.

The semiconductor bridge circuit may be a fully controlled three-phase bridge circuit. The at least one first semiconductor switch may be connected between the DC-DC converter and the AC voltage connection. The at least one second semiconductor switch can be connected to the first potential via the memory element.

The opening of the at least one first semiconductor switch comprises in particular: opening at least one semiconductor switch, which is part of a semiconductor bridge circuit of the inverter. The opening of the at least one second semiconductor switch comprises in particular: opening at least one semiconductor switch, which is also part of a semiconductor bridge circuit of the inverter.

The opening of the at least one first semiconductor switch further comprises, for example: opening at least one semiconductor switch, which is part of a semiconductor bridge circuit of the inverter. The opening of the at least one second semiconductor switch may include: opening at least one semiconductor switch which is part of a DC-DC converter connected between the energy store and the inverter.

The 1 and 2 show vehicle electrical systems with a power drive and serve to explain in more detail the procedure described here and the power drive device described here.

The 1 exemplifies a vehicle electrical system in which a power drive LS connects an electrical energy storage ES, in particular an accumulator, with an electric machine EM. In order to generate an alternating current from the DC voltage of the energy store ES, the power drive device LS comprises an inverter IN with a semiconductor bridge circuit provided by the switches 11 . 12 . 13 . 21 . 22 and 23 is formed. The bridge circuit of the inverter IN is a B6C bridge, wherein a branch is provided for each phase, which comprises two semiconductors connected in series. A first branch relating to a first phase of the electric machine is formed by the semiconductor switches 11 and 21 , another branch (concerning a second phase) is formed by the semiconductor switches 12 and 22 , and a third branch (concerning a third phase) is formed by the semiconductor switches 13 and 23 , Thus, the in 1 illustrated embodiment, three-phase, but the number of phases is not limited to this number. In particular, six phases can also be used.

In each branch there is a connection point A1, A2, A3, at which the semiconductor switches of a branch are connected to each other. The serially connected semiconductor switches of each branch are connected to a positive and a negative supply potential of the inverter IN. The connection points A1 - A3 are led to an AC voltage connection WA and correspond to the phase connections of the electrical machine.

A DC-DC converter DCDC, shown here as a synchronous converter, comprises a series connection of two semiconductor switches S1 and S2. The ends of this series circuit are connected to the inverter IN. Via an inductance IND, the connection point between the two switches S1 and S2 is connected to a first potential P of the energy store ES. The DC-DC converter DCDC and the inverter IN are further connected to ground M, wherein this also corresponds to the mass of the energy store, and may also be referred to as a second potential.

Via an AC voltage terminal WA, the power drive device LS is connected to the electric machine EM. The inverter is connected either directly to the first potential P or, as shown, via the optional DC-DC converter DCDC to the energy store ES.

In the illustrated embodiment, a controller C1, which may be part of or may be external to the inverter, part of the power driver, controls the semiconductor switches 11 to 23 of the inverter IN to generate a three-phase current from the DC voltage applied to the inverter in normal operation at the AC output WA. By means of this three-phase current, a magnetic rotating field is generated in the electric machine. The inverter can also be bidirectional and be configured to convert an AC voltage, which is applied to the AC voltage terminal WA, into a DC voltage for feeding the energy store ES. Further, the controller C1, the switches S1, S2 of the DC-DC converter DCDC are driven. The controller C1 is set up to control the switches for converting a DC voltage (into another DC voltage).

Alternatively, a controller C2 is provided, which has the same, aforementioned properties of the controller C1.

Both controllers have a disconnect signal input. The controller C1 has the isolation signal input which is in the 1 is called TEM. The disconnect signal input TEM relates to a disconnect signal which serves to disconnect the electrical machine to protect it (and associated components) when transmitting motion to the electrical machine (such as when towing). The disconnect signal intended for the disconnect signal input TEM relates to a normal mode of operation of the electrical machine in which the electrical machine is torque-free (and in particular is in rotation). The controller C1 is set up to open the at least one first switch and the at least one second switch upon receipt of the isolating signal at the isolating signal input TEM.

The controller C2 has the isolation signal input, which in the 1 is referred to as TES. The separation signal input TES relates to a separation signal which serves to separate the energy store ES from a connection interface AS and in particular from a stationary component L. The component L may be a charging station or a recovery station. The isolating signal intended for the isolating signal input TES can, on the other hand, reproduce a correctly terminated energy transmission between the connection interface (AS) or the stationary component (L) on the one hand and the energy store (ES) on the other hand. Alternatively, the isolating signal intended for the isolating signal input TES can reproduce an error in the transmission of electrical energy between the connection interface (AS) or the stationary component (L), on the one hand, and the energy store, on the other hand. In both cases, this serves to interrupt the connection between energy storage and connection interface by opening said switches of the power control device LS.

The controls C1 and C2 are arranged to open switches upon receipt of a disconnect signal. On the one hand, at least the switch is provided by the controller C1 or by the controller C2 (to this end) 11 open, but also the switches 12 and 13 and thus all switches can be opened, which are between the AC terminal WA and the supply potential of the inverter (corresponding to the positive output of the DC-DC converter). On the other hand, the switch C1 (of the DC-DC converter DCDC) is opened by the controller C1 and the (alternative) controller C2 upon receipt of the disconnection signal. Starting from the AC voltage terminal WA and a current path to the first potential P following are the switch 11 and the switch S1 (of the DC-DC converter DCDC) are connected in antiserial to each other, so that despite their inverse diodes (for example, the inverse diode 1 of the switch 11 ) in any direction a current can flow. This results in a complete separation between the DC voltage connection GA (to which the energy store ES is connected to the power control device ELS) and the AC voltage connection WA. The two anti-serially connected switches in the case of separation belong according to the example of 1 different components of the power drive device, namely the inverter IN and the DC-DC converter DCDC. Both anti-serially connected switches are connected to the same supply potential, namely to the positive supply potential of the inverter (corresponding to the positive output potential of the DC-DC converter DCDC). The first and second semiconductor switches are in this case directly connected to each other (but with opposite directions of operation).

The controls C1 and C2 are arranged in the illustrated embodiment to open upon receiving such a separation signal, the semiconductor switches. It can be provided that at least one further control is used for the function of the conversion for the inverter IN and the DC-DC converter DCDC, while for the function of opening the first and second Semiconductor switch, the controller C1 or the controller C2 is used. The further control can be connected downstream of the controller C1 or the controller C2 and controlled by them. Here, the control by C1 or C2 has priority over the function of the further control (namely, the operation of the DC-DC converter as such or the operation of the inverter as such), so that when an error signal, the respective switch (permanently) are opened.

The state of the energy storage ES causes the separation signal, which is delivered to the separation signal input TES, this being indicated by the dashed arrow between these components. The state of the energy store, such as its state of charge or fault condition requires the delivery of a disconnect signal to the controller C2. The electric machine ES is controlled and monitored by a motor control MS. If this detects, for example, a movement of the electric machine EM despite an inactive (i.e., no-current) electric machine, then the motor control MS acts on the separation signal input TEM. This may also be the case when the motor control MS detects an error, whereupon the controller opens the switch by the controller C1. The effect of the opening on the relevant first and second switches, driven by control C1, is symbolized by the dashed arrows between these components. This also applies to the controller C2. The controllers C1 and C2 represent different embodiments which aim at disconnecting the energy store for its protection (control C2) or at disconnecting the electric machine EM (control C1). Both controllers can be provided, in which case they preferably have common outputs for driving the switches and preferably separate isolation signal inputs TES, TEM.

In the 2 another vehicle electrical system is exemplified, which serves to further explain the procedure described.

Here, too, an energy store ES is connected to an electric machine EM via the power drive device. Here, the power drive LS has a DC voltage terminal GA, to which the energy store is connected, and an AC voltage terminal WA, to which the electric machine EM is connected. Again, the electric machine EM and the AC voltage terminal WA of the Leistungsansteuervorrichtung LS are multi-phase. An (optional) DC-DC converter DCDC may be provided, which is connected between the DC voltage terminal GA and the inverter IN of the power driver LS, or it may be provided no DC-DC converter DCDC, which realized differently depending on the operating voltages used of the energy storage and the electric machine can be.

The inverter IS comprises a multi-phase H bridge circuit. Each phase of the H bridge circuit of the inverter IN comprises two branches, each comprising two series-connected semiconductor switches. In each phase of the H-bridge circuit, a branch or series connection of two semiconductor switches is connected to a DC potential EA1, EA2 of the inverter (which may correspond to the terminals of the energy store). In other words, in each phase of the H bridge circuit, a branch of a pair of semiconductor switches is connected to a DC side of the inverter IN and to a DC terminal of the inverter, respectively.

In each phase, a second branch or a second series connection of two semiconductor switches is connected to the AC voltage terminal WA. The first branches or the first series circuits, which are connected to DC potential GA1, GA2 or to the energy store ES, are the semiconductor switches H1, H2 for the first phase, H11, H12 for the second phase and H21, H22 for the third phase , The series circuits of two semiconductor switches thus shown on the left side can be regarded as the DC side of the inverter, while the other branches or series circuits (H3, H4, H13, H14, H23, H24) can be considered as the AC side.

Parallel to the branches of the AC side of the inverter, capacitors C21, C22 and C23 are connected in parallel. As a bridge element between the branches of each phase in each case an inductance L1, L2 and L3 is connected in series. Relative to the electrical machine, the multi-phase H bridge circuit is thus connected in series between the DC voltage connection GA and the AC voltage connection WA.

A controller C, which may be part of the power drive device, is set up to drive the semiconductor switches H1 to H24 in normal operation in order to convert the DC voltage at the DC voltage terminal GA or at the supply potentials EA1, EA2 into an AC voltage at the AC voltage terminal WA. Optionally, the power drive device is also configured bidirectionally, so that the controller C can be configured to convert an AC voltage at the AC voltage terminal WA into a DC voltage at the DC voltage terminal GA.

The controller C1 comprises a separation signal input TEM, at which a separation signal can be received. The controller C1 is set up to open the switches between the phase terminals of the AC voltage terminal WA and the DC voltage terminal GA when the disconnection signal occurs at the input SE. For the upper phase these are the switches H1 and H3, for the middle phase they are the switches H11 and H13 and for the lower phase they are the switches H21 and H23. In the illustrated embodiment, those switches which are opened at a disconnect signal, the switches which are connected to the first potential of the energy store ES, in the illustrated case, the potential EA1, which may correspond to a positive pole. There are also complementary embodiments conceivable. Starting from the AC voltage connection WA to the DC voltage terminal GA leader in each phase, the switches open by the controller C are anti-parallel to each other. This results in a complete separation between the AC voltage terminal WA and the DC voltage terminal GA.

Alternatively, a controller C may be provided with a disconnect signal input FE as shown, which implements the step of opening, while another controller drives the semiconductor switches of the inverter in normal operation to produce a three-phase current.

As well as in 1 applies to 2 or for other embodiments, that the control for opening the semiconductor switch in the presence of a separation signal has priority, if this control does not correspond to the control that drives the semiconductor switches for normal operation (= conversion of voltage).

It should be noted that also in the 1 at least one switch is opened when a disconnect signal occurs (such as a switch 11 or the switches 11 . 12 and 13 ), which are between the AC voltage terminal and the first potential P, which in the 1 can correspond to the positive supply potential.

In the illustrated examples of 1 and 2 Further, an additional circuit breaker may be provided in the ground path, which is (directly) connected downstream of the energy storage, and which is also opened upon the occurrence of an error signal or separation signal.

As mentioned, the opening of the switches (also of the further switch) is permanent and in particular continues until a reset signal, in particular from the controller C1 and / or C2, has been detected. While in the 1 Preferably, both at least one switch of the inverter and a switch of the DC-DC converter DCDC are opened when an error signal occurs, in order to provide two mutually antiserial switches in the open state, it is in the embodiment of FIG 2 possible that two switches of the inverter itself be opened, in the case of 2 the switches H1 and H3, as well as the switches H11 and H13 and also the switches H21 and H23. The mutually antiserial switches, which are opened in the case of a disconnect signal, are connected in series to semiconductor switches, which are connected directly to ground or with a potential which does not correspond to the first potential.

The controllers C1 and C2 of the 2 have the same features and characteristics as the controllers C1 and C2 of the 1 ,

For both figures and also for other embodiments: A power drive device for an electric machine is described. An inverter IN of the device is connected between a DC voltage terminal GA of the device and an AC voltage terminal WA for the electric machine EM. The power drive device has a control, which is connected downstream of a semiconductor bridge circuit of the inverter IN. The semiconductor bridge circuit has at least one first semiconductor switch which lies between the AC voltage connection and a first potential of the DC voltage connection. A second semiconductor switch of the power drive device is antiserial to the at least one first semiconductor switch and connected to the first potential of the DC voltage terminal. The controller has a disconnect signal input for receiving a disconnect signal. The controller opens the at least one first and the at least one second semiconductor switch when a disconnect signal occurs.

Furthermore, a method for separating an electric machine EM from an electrical energy store ES is described, in which, upon detection of a disconnection signal, at least one first and at least one second semiconductor switch (connected in antiparallel) is opened. The semiconductor switches are connected between the electric machine EM and a first potential of a DC voltage terminal GA. The semiconductor switches are part of an inverter and optionally also a DC-DC converter DCDC between inverter IN and energy storage ES.

In the 1 and 2 in each case a network connection circuit T is shown, via which the electric machine EM is connected to the connection interface AS. This is optional and therefore shown in dashed lines. If no mains connection circuit T is provided, then the electric machine EM is connected directly to the connection interface AS. The mains connection circuit T is set up to set the configuration of the electrical machine, ie the interconnection of the individual windings. Different configurations can be set (star or triangle configuration) or the configuration can be resolved (and recreated) under control. Furthermore, the network connection circuit T can be set up to connect or disconnect the electrical machine in a controlled manner to the connection interface AS. The network connection circuit T has switching elements for this purpose. The grid connection circuit T can be controlled by the motor controller MS or by the controller C1 and / or C2. The mains connection circuit T may comprise a filter, overvoltage protection, overcurrent protection and / or at least one sensor for detecting at least one magnitude (phase, power, current, voltage, power factor,...) Of the AC signal present between the electrical machine and the connection interface AS flows.

Claims (10)

A vehicle powertrain having a power driver (LS) and an electric machine (EM), said power driver (LS) being provided with a DC voltage terminal (GA) and an inverter (IN) connected between said DC voltage terminal (GA) and an AC power terminal (WA ) is connected to the connection of the electric machine (EM) and which comprises a semiconductor bridge circuit (11-23; H1-H24), wherein the power drive device comprises a controller (C1, C2) which is connected to the semiconductor bridge circuit (11-13; 23, H1-H24), wherein the semiconductor bridge circuit (11-23; H1, H11, H21) comprises at least one first semiconductor switch (11-13; H1, H11, H21) connected between the AC voltage terminal (WA) and a first potential (P; EA1) of the DC voltage terminal (GA), and the power driver (LS) further comprises at least one second semiconductor switch (S1; H3, H13, H23) antiserially connected to the at least one first semiconductor switch (11-13; H1-H21) and at the first potential (P; EA1) of the DC voltage terminal is connected, wherein the controller (C1, C2) further comprises a disconnect signal input (TES, TEM) arranged to receive a disconnect signal and the controller (C1, C2) is arranged to open the at least one first semiconductor switch and the at least one second semiconductor switch when the disconnect signal occurs wherein the disconnect signal represents a normal mode of operation of the electric machine (EM) in which the electric machine (EM) is torqueless. Vehicle drivetrain behind Claim 1 wherein the disconnect signal represents a towing mode of the vehicle powertrain in which the electric machine is mechanically powered or a park mode in which the vehicle is parked. Vehicle drivetrain behind Claim 1 or 2 , with an electrical energy store (ES) and a connection interface (AS), which is used for transmitting electrical Energy between the energy storage device (ES) and a stationary component (L) is set, wherein the connection interface (AS) via the electric machine (EM) to the power drive device (LS) is connected and the separation signal a properly terminated energy transfer between the connection interface (AS ) or the stationary component (L) on the one hand and the energy storage on the other hand or a safe state before the start of the charging process. A vehicle powertrain having a power driver (LS) and an electric machine (EM), said power driver (LS) being provided with a DC voltage terminal (GA) and an inverter (IN) connected between said DC voltage terminal (GA) and an AC power terminal (WA ) is connected to the connection of the electric machine (EM) and which comprises a semiconductor bridge circuit (11-23; H1-H24), wherein the power drive device comprises a controller (C1, C2) which is connected to the semiconductor bridge circuit (11-13; 23, H1-H24), wherein the semiconductor bridge circuit (11-23; H1, H11, H21) comprises at least one first semiconductor switch (11-13; H1, H11, H21) connected between the AC voltage terminal (WA) and a first potential (P; EA1) of the DC voltage terminal (GA), and the power driver (LS) further comprises at least one second semiconductor switch (S1; H3, H13, H23) antiserially connected to the at least one first semiconductor switch (11-13; H1-H21) and at the first potential (P; EA1) of the DC voltage terminal is connected, wherein the vehicle drive train, the control (C1, C2) further comprises a separation signal input (TES) arranged to receive a separation signal and the controller (C1, C2) is arranged, the at least one first semiconductor switch and to open the at least one second semiconductor switch when the isolation signal occurs, wherein the vehicle drive train comprises an electrical energy store (ES) and a connection interface (AS), which is arranged for transmitting electrical energy between the energy store (ES) and a stationary component (L), wherein the connection interface (AS) via the electrical Machine (EM) is connected to the Leistungsansteuervorrichtung (LS) and the separation signal reflects an error in the transmission of electrical energy between the connection interface (AS) or the stationary component (L) on the one hand and the energy storage on the other. Vehicle drivetrain behind Claim 4 wherein the isolation signal represents an error within the energy storage (ES) or within the electrical machine or within the stationary component. Vehicle drivetrain behind Claim 3 . 4 or 5 , wherein the connection interface (AS) is connected to the power drive device only via the electrical machine (EM), or is connected to the connection interface (AS) via a network connection circuit (T). Method for separating an electric machine (EM) from an electrical energy store (ES), comprising: Detecting a disconnection signal representing a normal operation mode of the electric machine (EM) in which the electric machine (EM) is torqueless; and Opening at least one first semiconductor switch (11-13; H1, H11, H21) and at least one second semiconductor switch (S1; H3, H13, H23) connected in anti-parallel with the first semiconductor switch, the semiconductor switches being connected between the electrical machine (EM) and a first potential (P, EA1) of a DC voltage terminal (GA), wherein at least one of the first and second semiconductor switches is part of an inverter (IN) connected between the electrical energy store (ES) and the electric machine (EM). Method according to Claim 7 wherein the disconnect signal represents a towing mode of the vehicle powertrain, and the electric machine is disconnected while mechanically driven, such as during a towing operation, or wherein the disconnect signal represents a park mode in which the vehicle is parked and the electric machine disconnected when the vehicle is parked or already parked. Method according to Claim 7 wherein the electric machine is disconnected while electrical energy is transferred via the electric machine between an electrical energy store (ES) and a stationary component (L), and the disconnect signal a properly terminated energy transfer between the stationary component (L) on the one hand and the Energy storage on the other hand reflects, in particular an end of a charging phase of the energy storage (ES). Method for separating an electric machine (EM) from an electrical energy store (ES), comprising: Detecting a disconnect signal, the disconnect signal representing an error in the transmission of electrical energy through the electric machine (EM) and between a stationary component (L) and the energy store (ES); and Opening at least one first semiconductor switch (11-13; H1, H11, H21) and at least one second semiconductor switch (S1; H3, H13, H23) connected in anti-parallel with the first semiconductor switch, the semiconductor switches being connected between the electrical machine (EM) and a first potential (P, EA1) of a DC voltage terminal (GA), wherein at least one of the first and second semiconductor switches is part of an inverter (IN) connected between the electrical energy store (ES) and the electric machine (EM).

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