VEHICLE-SIDE CHARGING CIRCUIT FOR A VEHICLE WITH ELECTRIC DRIVE, AND METHOD FOR OPERATING A VEHICLE-SIDE CURRENT CONVERTER, AND USE OF AT LEAST ONE WINDING OF A VEHICLE-SIDE ELECTRIC MACHINE FOR INTERMEDIATE STORAGECTRICAL MACHINE FOR BUFFER

Abstract

A vehicle-side charging circuit for a vehicle with electric drive. The charging circuit comprises an AC connector, a controlled rectifier which is connected to the AC connector, an electric machine with at least one winding, a current converter which is connected to the electric machine, and an energy-storage-device connector. The at least one winding of the electric machine is coupled in series between the rectifier and the current converter. In an inverter mode the current converter is fed from the energy-storage device, and in a charging mode the current converter is from an external energy source via at least one series-connected winding of the electric machine and charges the electrical energy-storage device.

Claims

1. A vehicle-side charging circuit for a vehicle with electric drive, said charging circuit comprising: an AC connector; a controlled rectifier which is connected to the AC connector; an electric machine with at least one winding; a current converter which is connected to the electric machine; and an energy-storage-device connector; wherein the at least one winding of the electric machine is coupled in series between the rectifier and the current converter.

2. The vehicle-side charging circuit as claimed in claim 1, with a control device which is connected in triggering manner to the current converter, wherein the control device has been set up to operate the current converter in a first state in an inverter mode, and in a second state in a charging mode, wherein the control device has been set up in the inverter mode to trigger the current converter to transform the voltage applied to the energy-storage-device connector into a triggering signal with which the electric machine can be operated; and the control device has been set up in the charging mode to trigger the current converter to transform the voltage that is output by the rectifier to the current converter via the at least one winding into a charging signal which can be output to the energy-storage-device connector for the purpose of charging an energy-storage device coupled thereto.

3. The vehicle-side charging circuit as claimed in claim 2, wherein an EMC filter (22) is coupled between the rectifier and the AC connector.

4. The vehicle-side charging circuit as claimed in claim 3, wherein a smoothing capacitor is connected in parallel between the rectifier and the electric machine.

5. The vehicle-side charging circuit as claimed in claim 4, wherein a disconnecting switch is connected in series between the rectifier and the electric machine.

6. The vehicle-side charging circuit as claimed in claim 5, wherein the electric machine exhibits a locking actuator which exhibits a locking bar which can selectively arrest or release a rotor of the electric machine in controlled manner.

7. The vehicle-side charging circuit as claimed in claim 6, wherein the electric machine is a traction machine or a starter/generator or a generator or a starter of the vehicle, or the electric machine is a motor of an ancillary unit of the vehicle.

8. A method for operating a vehicle-side current converter to which an electric machine and an electrical energy-storage device are coupled, wherein in an inverter mode the current converter is fed from the energy-storage device and generates a triggering signal with which the electric machine is operated, and in a charging mode the current converter is fed via at least one series-connected winding of the electric machine from an external energy source via an AC circuit and via a controlled rectifier and generates a charging signal which is supplied to the electrical energy-storage device; wherein in the charging mode the at least one winding of the electric machine together with the current converter form a power transformer in which the at least one winding operates as a storage inductor.

9. The method as claimed in claim 8, wherein the rectifier is controlled in order to adjust an effective current or a voltage.

10. The method as claimed in claim 8, wherein in the charging mode a locking bar of a locking actuator mechanically locks the electric machine, and in the inverter mode the locking bar does not lock the electric machine.

11. Use of at least one winding of a vehicle-side electric machine for intermediate storage of energy within the scope of a power transformation, by which electrical power is transmitted in controlled manner via an AC connector to a vehicle-side electrical energy-storage device, wherein a current converter of the electric machine, which is assigned to the latter as an inverter, is used for power transformation, wherein the current converter and the at least one winding of the electric machine are used together as a controllable DC voltage transformer; and within the scope of the use of the at least one winding of the electric machine for intermediate storage of energy a rectifier is used to transform the current that is fed in via the AC connector into direct current, wherein the at least one winding and the current converter receive this direct current for the purpose of controlled transformation, in order to output the transformed current to a electrical energy-storage device, and the controllable rectifier adjusts the magnitude of the effective DC voltage which is output by the rectifier and delivered to the electric machine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is an overview of a system that is suitable for elucidating the invention.

DETAILED DESCRIPTION

[0035] FIG. 1 shows a vehicle-side charging circuit 10 which via a (single-phase, where appropriate also three-phase) AC connector 20 is connected to an external electrical-energy source 24 which outputs alternating current. The source of electrical energy is outside the vehicle, for instance in the form of a charging station, and is therefore not a part of the charging circuit 10. Connected downstream of the AC connector 20 of the charging circuit 10 is an EMC filter 22. Connected downstream of the EMC filter 22 is, in turn, a rectifier 30. The rectifier 30 takes the form, in particular, of a rectifier circuit of diodes, thyristors or transistors (in particular, MOSFETs). The rectifier 30 may therefore be semi-controlled or may be implemented to be controllable, in particular controllable in accordance with a phase-angle control. A control device 80 is connected in triggering manner to the rectifier 30 which is implemented to be controllable or semi-controllable, the arrow between these two components representing the triggering direction.

[0036] The rectifier 30 is connected to the AC connector 20, preferentially, as represented, via an optional EMC filter 22. The optional EMC filter is represented by dashed lines, in which connection components represented by dashed lines are generally to be regarded as optional.

[0037] Connected downstream of the rectifier 30 is an optional smoothing capacitor 32. The smoothing capacitor 32 is located on a DC side 31a of the rectifier 30. Located on an AC side 31b of the rectifier 30, which (with respect to the rectifier 30) is located opposite the DC side 31a, is/are the AC connector 20 and, where appropriate, the optional EMC filter 22. The rectifier 30 connects the AC connector 20 (and, where appropriate, the optional EMC filter 22) to an electric machine 40.

[0038] An optional smoothing capacitor may be connected in parallel between the electric machine 40 and the rectifier 30. Furthermore, the electric machine 40 may be connected to the rectifier 30 or to the DC side 31a thereof via an optional disconnecting switch 34. The disconnecting switch 34 may be arranged, in particular, in the ground rail (the lower rail in FIG. 1), but may, alternatively or in combination with this, also be provided in the positive supply rail (the upper rail in FIG. 1).

[0039] The electric machine 40 and, in particular, the several windings 50a-c thereof are connected downstream of the rectifier 30 which is connected to the AC connector 20. The several windings 50a-c form a three-phase system and are connected up in star configuration. A locking actuator 42 is assigned to the electric machine 40 and has been set up to lock the rotor thereof. The mechanical action of the locking actuator 42 is represented by the arrow between the locking actuator 42 and the electric machine 40. The locking actuator 42 is triggered by the control device 80.

[0040] The windings 50a-c each exhibit an end, these ends of the windings 50a-c being connected to one another via a neutral point S. The rectifier 30 (in particular, the positive output thereof) is connected to the neutral point. The rectifier 30 is furthermore connected to a current converter 60, a negative output of the rectifier 30 being connected to the current converter 60 (or to the negative supply rail thereof). The outputs of the rectifier 30 correspond to the connectors on the DC side 31a of the rectifier 30. The windings 50a-c furthermore each exhibit an end that is opposed to the neutral point S (or to the rectifier 30). These ends of the windings 50a-c are connected to the current converter 60. The current converter 60 includes a B6C bridge (controlled by a control device 80). The current converter is consequently configured as a full bridge and is three-phase. For each of the three phases, two controllable semiconductor switches (represented as thyristors in FIG. 1) are provided. The semiconductor switches have a blocking direction and a forward direction. Furthermore, the semiconductor switches have a control input, so that the conduction state or switching state in the forward direction can be controlled. The control inputs are connected to the control device 80. The two semiconductor switches of each of the three phases are connected in series, an associated winding in particular, an end of the winding 50a-c that is opposed to the neutral point being coupled to the connecting point. The respective two series-connected semiconductor switches are coupled between the negative supply rail and a positive supply rail, and connect said rails The two series-connected semiconductor switches are (at least in the inverter mode) never simultaneously in the conducting switching state. Each winding 50a-c is connected to the positive supply rail of the current converter 60 via a semiconductor switch and connected to the negative supply rail of the current converter 60 via a further semiconductor switch.

[0041] The current converter 60 is furthermore connected to an energy-storage-device connector 70. In particular, the two supply-voltage rails of the current converter 60 are connected to the energy-storage-device connector 70. The energy-storage-device connector 70 is a DC connector. An electrical energy-storage device 90, in particular a high-voltage storage battery, is coupled to the energy-storage-device connector 70. The energy-storage device 90 is not part of the charging circuit 10. With the exception of the external source of electrical energy, all the components represented (and also all the components described) are arranged on the vehicle side and are consequently intended to be arranged in a vehicle or to form part of an on-board vehicle network.

[0042] An optional matching DC/DC transformer 72 is represented in FIG. 1. Via this transformer the current converter 60 is connected to the energy-storage-device connector 70. The matching DC/DC transformer 72 is preferentially a step-up transformer. The matching DC/DC transformer 72 serves for adapting the voltage delivered by the current converter to an operating voltage of the energy-storage device 90. The matching DC/DC transformer 72 is represented as a part of the charging circuit 10. However, the matching DC/DC transformer 72 may also be regarded as a component of the energy-storage device, with which charging voltages can be adapted to set voltages of a cell stack of the energy-storage device.

[0043] The charging device 10 realizes a charging function, but components of the electric drive (in particular, the windings 50a-c of the electric machine 40, and the current converter 60 which serves as inverter) are used for this purpose. By reason of this dual use, the charging device 10 may also be designated as a (wired-up) electric drive with charging function. The windings 50a-c of the electric machine are, in particular, stator windings. In the case of externally excited electric machines, the excitation current has been switched off in the charging mode by reason of the triggering by means of the control device 80, and switched on in the inverter mode.

LIST OF REFERENCE SYMBOLS

[0044] 10 vehicle-side charging circuit [0045] 20 AC connector [0046] 22 EMC filter [0047] 24 external electrical-energy source [0048] 30 Rectifier [0049] 32 smoothing capacitor [0050] 34 disconnecting switch [0051] 40 electric machine [0052] 42 locking actuator [0053] 50a-c at least one winding of the electric machine 40 [0054] 60 current converter [0055] 70 energy-storage-device connector [0056] 72 matching DC/DC transformer [0057] 80 control device [0058] 90 electrical energy-storage device [0059] S neutral point