Multifunctional DC-to-DC converter, DC-to-AC converter, and AC-to-DC converter

Abstract

Power converter circuit (40, 60, 80, 90, 94, 96, 98) with the following features: a bridge circuit (42) with three half-bridges (42a, 42b, 42c); three chokes (44a, 44b, 44c) each connected to a central node (45a, 45b, 45c) of the half-bridges (42a, 42b, 42c); a switching network (46) configured to connect the three chokes (44a, 44b, 44c) in a switchable manner to an AC voltage terminal (24) and a first DC voltage terminal (18); and a second DC voltage connection (32) which is connected to a first common potential path (48a) of the bridge circuit (42) and a second common potential path (48b) of the bridge circuit (42); wherein the power converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to put the switching network (46) into a first switching state (50) in which the three chokes (44a, 44b, 44c) are coupled via the switching network (46) to three different phase terminals (24a, 24b, 24c) of the AC voltage terminal (24) in order to provide grid feedback based on a DC voltage (V) applied to the second DC voltage terminal (32) 32ab ) at the AC voltage terminal (24) an alternating voltage (V 24a , V 24b , V 24c ) to provide, and wherein the converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to operate in the first switching state (50) of the switching network (46) based on an alternating voltage (V) applied to the AC voltage terminal (24). 24a , V 24b , V 24c ) at the second DC voltage terminal (32) a DC voltage (V 32ab ) to provide, and wherein the converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to put the switching network (46) into a second switching state (52) in which a first choke (44a) of the three chokes (44a, 44b, 44c) is coupled via the switching network (46) to one of the phase terminals (24a, 24b, 24c) of the AC voltage terminal (24) in order to provide grid feedback based on a DC voltage (V) applied to the second DC voltage terminal (32) 32ab ) at the AC voltage terminal (24) an alternating voltage (V 24ab ) to provide, and in which another of the three chokes (44a, 44b, 44c) is coupled via the switching network (46) to the first DC voltage terminal (18) to provide, based on a DC voltage (V) applied to the second DC voltage terminal (32) 32ab ) at the first DC voltage terminal (18) a DC voltage (V 18ab) to provide or based on a DC voltage (V) applied to the first DC terminal (18) 18ab ) at the second DC voltage terminal (32) a DC voltage (V 32ab ) to provide, and wherein the power converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to operate in the second switching state (52) of the switching network (46) in the opposite direction of energy flow based on an alternating voltage (V) applied to the AC voltage terminal (24). 24ab ) at the second DC voltage terminal (32) a DC voltage (V 32ab ) to provide, and based on a DC voltage (V) applied to the first DC terminal (18) 18ab ) at the second DC voltage terminal (32) a DC voltage (V 32ab ) to provide or based on a DC voltage (V) applied to the second DC terminal (32) 32ab) at the first DC voltage terminal (18) a DC voltage (V 18ab to provide.

Description

Technical field

[0001] Exemplary embodiments of the present invention relate to a power converter circuit for multifunctional current direction, such as DC-to-DC, DC-to-AC, and AC-to-DC, using a switching network, a bridge circuit (for example, in the form of power electronics), and inductors. Possible applications for such power converter circuits include devices for charging and discharging batteries in electric vehicles or similar applications. One exemplary embodiment of the present invention provides a multifunctional power converter for current direction from DC-to-DC, DC-to-AC, and AC-to-DC. Background of the invention

[0002] Currently, electric vehicle batteries are often charged using a suitable charger via a (low-voltage) AC power line cable. This charging is typically done either single-phase or three-phase. By using battery inverters, energy can be fed back into an AC power grid or an island grid, or an island grid can be created.

[0003] Most AC / DC converters can also be directly connected to a DC power grid or other DC voltage sources, such as a DC generator or inductive energy transfer unit, to charge the battery. Feeding power back into the DC power grid is conventionally only possible with an additional DC / DC converter.

[0004] Most current chargers can charge using both voltage types. However, it has been found that, in the context of planned future grid feed-in (e.g., from batteries previously charged using renewable energy), a bidirectional, intelligent charger is needed for grid support or intermediate storage, which can supply the absorbed energy back to the grid via cable as well as wirelessly.

[0005] To provide such charging infrastructure with the capability to feed energy back into DC and AC grids, several components are conventionally used. These are expensive, space-consuming, and heavy, as will be explained below using the state of the art as an example.

[0006] Fig. Figure 4 shows a conventionally used charging infrastructure 10, comprising a first DC-DC converter 12, an AC-DC converter 14, and a second DC-DC converter 16. The three converters 12, 14, and 16 are interconnected via a common DC network 15. Structurally, the common DC network 15 consists of a first Y-connection 15a between the three converters 12, 14, and 16 for the first pole of the common DC network and a second Y-connection 15b for the second pole of the common DC network.

[0007] The first DC-DC converter 12 is connected to a DC network 20 via a first DC connection 18, which has a first pole 18a and a second pole 18b, and can thus generate a DC voltage V 18abfrom a DC voltage source 20. The AC-DC converter 14 is connected via three phase terminals 24a, 24b and 24c of a three-phase AC voltage connection 24, each for one phase of the AC voltage V. 24a , V 24b and V 24c The first DC-DC converter is connected to an AC power network 26. The second DC-DC converter 16 has a second DC terminal 32, comprising a first pole 32a and a second pole 32b, and can thus be connected, for example, to a battery 30. The DC-DC converter 16 serves to adapt a DC voltage V 32ab or a charging current for battery 30.

[0008] Thus, the charging infrastructure 10 enables the battery 30 to be charged from an AC power grid 26 and from a DC power grid 20, such as a generator, a supercapacitor (also known as a super-cap), or a similar device. All components of the charging infrastructure 10 operate bidirectionally and can therefore feed energy from the battery 30 back into the AC power grid 26 or the DC power grid 20. Such a charging infrastructure, which comprises three individual converters 12, 14, and 16, requires a large amount of space, is heavy, and is expensive.

[0009] The following describes the state of the art based on five patent applications for charging systems and methods for charging a vehicle battery and / or for a vehicle with such a charging system. Some of these applications utilize existing vehicle components for charging or regenerative braking to solve space and weight constraints. These include, for example, the power electronics of the drive inverter and motor windings.

[0010] German patent application DE 10 2009 033 185 A1 describes a device that charges the battery via the power electronics of the drive inverter. The inverter is used as a passive rectifier. Essentially, an AC-to-DC conversion takes place; this is operated with variable amplitude and frequency in drive mode. A switching device connects either the motor or the AC mains to the drive inverter. However, it was found that this system is not capable of regenerative braking. Furthermore, it was found that bidirectional exchange, whether simultaneous or non-simultaneous, with another DC voltage source is apparently not possible.

[0011] German patent application DE 10 2009 017 087 A1 also assumes that the battery is charged via the power electronics of the drive inverter and the motor windings. This essentially involves a DC-to-DC conversion. A contactless energy transfer path is connected to a star point of the motor. The motor windings act as inductors. The inverter, in conjunction with the motor windings, is used as a boost converter. In drive mode, a DC-to-AC conversion is operated with variable amplitude and frequency. However, it was recognized that this galvanically isolated system is not capable of regenerative braking and that no bidirectional exchange, simultaneous or non-simultaneous, with an AC voltage source is possible.

[0012] German patent application DE 10 2009 021 797 A1 also describes a concept for charging the battery via the power electronics of the drive inverter and the motor windings, essentially involving DC-to-DC conversion. A galvanically isolated, wired mains charging device is connected to a neutral point of the motor. Similar to the concept described in German patent application DE 10 2009 017 087 A1, the inverter is used as a boost converter, with the motor windings forming the inductors. In drive mode, an AC-to-DC converter is operated with variable amplitude and frequency.

[0013] It was recognized that the system is not capable of feedback and is also not bidirectional, simultaneous or non-simultaneous operation.

[0014] Another concept for charging the battery via the power electronics of the drive inverter and the motor windings is described in German patent application DE 10 2009 007 960 A1. The mains charging device is based on a DC-to-DC converter connected to the motor's neutral point and is not galvanically isolated. The inverter is used as a boost converter, with the motor windings forming the inductors. In drive mode, a DC-to-AC converter is also operated with variable amplitude and frequency, analogous to the systems described. It was found that the system is not capable of regenerative braking and that bidirectional exchange, simultaneous or non-simultaneous, with other DC voltage sources is not possible.

[0015] German patent application DE 10 2009 033 955 A1 describes a charging device for a battery via the power electronics of the drive inverter and the motor windings, which is capable of regenerative braking. During charging, an AC-to-DC conversion essentially takes place. The mains connection device is coupled to a switching unit that disconnects the motor's neutral point and simultaneously connects the motor windings. The inverter is used as an active rectifier, with the motor windings forming the inductors. In drive mode, the DC-to-AC conversion is operated with variable amplitude and frequency. The described system is capable of single-phase or three-phase regenerative braking; however, complying with the relevant standards for mains regeneration is difficult, as the motor windings are often not designed for such applications.However, it was recognized that simultaneous charging of the battery by single-phase AC and DC voltage using the same power electronics is not possible; consequently, either a single-phase AC voltage source, a three-phase AC voltage source, or a DC voltage source would be required. Furthermore, it is evident that charging from a DC source or feeding energy back into a DC network would involve significant losses due to the network topology.

[0016] German patent application DE 10 2009 000 096 A1 discloses a method for controlling a power supply unit for at least one electric machine with a battery and an inverter comprising at least one choke. This patent application describes the dual function of the inverter, which enables single-phase and three-phase charging of the battery and is designed to supply power to the electric machine during operation.

[0017] DE 696 17 026 T2 describes a system for charging a motor vehicle battery from a single-phase voltage source, wherein the motor vehicle is equipped with a three-phase motor with three windings and an inverter with three breakers. During charging, the motor windings of one of the breakers are used for DC-to-DC conversion and the other two breakers for AC-to-DC conversion.

[0018] WO 93 / 01650 A1 discloses a method and a device for operating an inverter of a three-phase drive of an electric car as an on-board charger. This essentially describes single-phase charging with a traction converter, where two of the three half-bridges are provided for the single-phase AC voltage connection and the third functions as a buck converter connected in series. US 2010 / 0201341 A1 discloses a three-legged power converter. In this three-legged converter circuit, several independent inputs are combined to produce a regulated AC output.

[0019] DE 102008063465 A1 describes an operating arrangement comprising a battery, an inverter and an electric motor for an electrically powered vehicle as well as an operating method for such an arrangement.

[0020] The object of the present invention is to create a power converter circuit that provides a better compromise between space requirements, weight requirements, cost and versatility. Summary of the invention

[0021] The problem is solved by a power converter circuit according to claim 1.

[0022] A power converter circuit according to an embodiment of the present invention comprises a bridge circuit with three half-bridges, three inductors, each connected to a central node of a half-bridge, and a switching network configured to connect the three inductors in a switchable manner to an AC voltage input and a first DC voltage input. The power converter circuit further comprises a second DC voltage input connected to a first common potential path of the bridge circuit and a second common potential path of the bridge circuit.

[0023] The power converter circuit is designed to put the switching network into a first switching state in which the three chokes are coupled via the switching network to three different phase terminals of the AC voltage terminal in order to provide an AC voltage at the AC voltage terminal based on a DC voltage applied to the second DC voltage terminal, or to provide a DC voltage at the second DC voltage terminal based on an AC voltage applied to the AC voltage terminal.

[0024] The power converter circuit is also designed to put the switching network into a second switching state, in which a first inductor of the three inductors is coupled via the switching network to one of the phase terminals of the AC voltage terminal, in order to provide an AC voltage at the AC voltage terminal based on a DC voltage applied to the second DC voltage terminal, or to provide a DC voltage at the second DC voltage terminal based on an AC voltage applied to the AC voltage terminal, and in which another inductor of the three inductors is coupled via the switching network to the first DC voltage terminal.to provide a DC voltage at the first DC terminal based on a DC voltage applied to the second DC terminal, or to provide a DC voltage at the second DC terminal based on a DC voltage applied to the first DC terminal.

[0025] The insight of the present invention lies in the fact that the power converter circuit, through a clever interconnection of the switching network, uses the three chokes and the bridge circuit with the three half-bridges both for DC-DC conversion between the first DC terminal and the second DC terminal or vice versa, and for AC-DC conversion from the AC terminal to the second DC terminal or vice versa, and furthermore also enables simultaneous DC-DC conversion and AC-DC conversion using the first and second DC terminals and the AC terminal via these three chokes and the bridge circuit.

[0026] It has been recognized that the range of a vehicle, and especially an electric vehicle, depends significantly on the weight it carries; therefore, in advantageous embodiments, existing components such as chokes or bridge circuits are used for multiple applications. In a vehicle, installation space is limited and can be utilized for other purposes, such as the battery, through further integration of the power electronics. A further advantage lies in cost minimization, achieved by reducing the number of components through the dual use of existing ones.

[0027] Further embodiments of the present converter circuit are designed to selectably switch the switching network, depending on state selection information, into one of at least five switching states achievable by the converter circuit, in each of which a different voltage conversion is provided using the three chokes and the three half-bridges: The first switching state is used to convert three-phase AC voltage, applied to three different phase terminals of the AC terminal, into DC voltage at the second DC terminal, or vice versa. The second switching state is used for the simultaneous conversion between single-phase AC voltage, applied to one phase terminal of the AC terminal with respect to a neutral conductor, or between two phase terminals of the AC terminal, and DC voltage at the second DC terminal, while simultaneously providing or drawing DC voltage at the first DC terminal. This is achieved by controlling one or more half-bridges of the bridge circuit, which are connected between the common potential conductors and the AC terminal, or which are connected between the common potential conductors and the first DC terminal.Since an opposite energy flow direction results, a total of four different conversion modes are possible in this second switching state, such as the conversion of DC voltage at the second DC terminal to DC voltage at the first DC terminal, while simultaneously providing AC voltage at the AC terminal; or the conversion of AC voltage at the AC terminal to DC voltage at the second DC terminal, while simultaneously converting DC voltage at the first DC terminal to DC voltage at the second DC terminal; the two further modes are conversion of DC voltage at the first DC terminal to DC voltage at the second DC terminal.when simultaneously supplying alternating voltage at the alternating voltage terminal or converting alternating voltage at the alternating voltage terminal into direct voltage at the second direct voltage terminal, or when simultaneously converting direct voltage at the second direct voltage terminal into direct voltage at the first direct voltage terminal.

[0028] A third switching state allows the conversion of single-phase AC voltage at the AC terminal to DC voltage at the second DC terminal, or vice versa. A fourth switching state, using the three chokes and the bridge circuit, enables the conversion of a so-called "split phase," i.e., a two-phase AC voltage. In this state, the first phase is applied between the first and second phase terminals of the AC terminal, and the second phase, rotated by 180°, is applied between the third and second phase terminals of the AC terminal. The second phase terminal of the AC terminal serves as the neutral conductor.The fifth switching state is used to convert DC voltage to DC voltage between the first and second DC terminals. It should be noted that the conversion of DC voltage to DC voltage between the first and second DC terminals refers both to providing DC voltage at the first DC terminal based on DC voltage at the second DC terminal, and vice versa. The advantage of the multifunctionality achieved through the various switching states is that, for example, a battery connected to the second DC terminal can be charged using different voltage forms, such as single-phase or three-phase AC voltage or DC voltage, e.g., via an inductive energy transfer device or a solar panel. If required, simultaneous charging using different energy forms, i.e., DC and AC voltage, is also possible.Another advantageous application is the intermediate storage of energy in a further energy storage device, such as a supercapacitor, which has a different energy storage characteristic, via the first DC input. A further advantage is that the converter can also be operated with split-phase operation, which is particularly important for use in the North American market. Another advantage is that in the fifth switching state, the DC-DC conversion can take place at maximum power, even if each of the three half-bridges is only designed for one-third of the maximum power, since in this switching state all three half-bridges can be used together with the three inductors.

[0029] In exemplary embodiments of the power converter circuit, three half-bridges, each with at least two bridge switches preferably implemented using semiconductor components, are employed for the bridge circuit. The advantage here is that semiconductor components are cost-effective and can be controlled by (e.g., external) logic to enable, for example, the conversion of alternating current to direct current and vice versa with the aid of inductors, by appropriately controlling the bridge switches. The direction of energy flow can be set, for instance, by appropriately selecting the timing ratios.

[0030] To define the respective switching state, the switching network can include three switches for the selective, switchable coupling of the three inductors to the three phase terminals of the AC voltage input. Furthermore, in exemplary embodiments, the coupling of the first DC voltage input to the three inductors is implemented via three switches for selective, switchable coupling. These switches for the DC voltage input and the AC voltage input can each be controlled individually. This results in the advantageous property that a particularly large number of conversion modes, and especially conversion modes for the simultaneous conversion of different energy forms, such as single-phase AC voltage to DC voltage and DC voltage to DC voltage, can be set.

[0031] In exemplary embodiments, a neutral conductor can additionally be coupled to the three chokes via three capacitors by means of a switch, which enables advantageous filtering of the fed-back single-phase, split-phase and / or three-phase AC voltage, so that the relevant standards for grid feedback can be complied with.

[0032] In the described embodiment, the power converter circuit serves, for example, as a replacement for an onboard charger. This has the advantage of improving efficiency, as the power electronics and inductors can be optimally designed for the bidirectional conversion of DC voltage to DC voltage and DC voltage to AC voltage, and thus optimally for the power required to charge the battery or to feed DC or AC voltage back into the grid. Furthermore, it is advantageous that, in this embodiment, charging or energy regeneration is also possible during drive operation by using additional power electronics for the drive converter. In contrast, in the following embodiment, the power converter circuit is also used as power electronics for the drive converter.

[0033] In exemplary embodiments, additional power electronics for the drive converter circuit can be omitted if an electric machine, also called an E-machine, is connected. For this purpose, the switching network comprises three changeover switches, with the converter circuit configured to connect the three phases of the AC voltage supply to the chokes in a first switching position of the changeover switches, and to connect a single-phase or three-phase E-machine to the chokes in a second switching position. The E-machine can preferably, but not necessarily, be operated in drive mode and in generator mode. An advantage of this is that no additional, space-consuming, costly, and heavy power electronics are required for the drive converter. A further advantage is the possibility of current smoothing for the drive via the three chokes.

[0034] In exemplary embodiments, in addition to the conversion of DC voltage to AC voltage or vice versa, a voltage conversion to a higher or lower voltage can simultaneously take place, for example, by 10% higher or lower than the corresponding output value (comparison of the magnitudes of the DC voltages or comparison of the magnitude of the DC voltage with the RMS value of the AC voltage). Likewise, in exemplary embodiments, a voltage conversion can take place between the DC voltage at the first DC voltage terminal and the DC voltage at the second DC voltage terminal. In a further exemplary embodiment, a DC-to-DC converter can be provided at the second DC voltage terminal for further voltage conversion. This offers the advantage that a change in the DC voltage, e.g.,This is possible for a high-voltage battery, while simultaneously achieving high efficiency and allowing the battery to be charged with constant current and amperage. Furthermore, this has the advantage that a DC voltage (output voltage) lower than the passively rectified AC voltage (mains voltage) can be provided.

[0035] In summary, embodiments according to the present invention create a device that combines several power converters for the different conversion modes (bidirectional DC-DC conversion, bidirectional AC-DC conversion including bidirectional DC-AC conversion and a combination of the different conversion modes), wherein this device is cost-efficient, space-efficient and / or weight-efficient. Character description

[0036] Exemplary embodiments of the invention are explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 a schematic representation of a power converter circuit according to a first embodiment; Fig. 2a a circuit diagram of a power converter circuit according to a second embodiment; Fig. 2b a circuit diagram of a power converter circuit according to a third embodiment; Fig. 3a-3d Equivalent circuit diagrams for representing switching states of a power converter circuit according to one of the embodiments; and Fig. 4 a schematic representation of a power converter circuit according to the state of the art. Detailed description of the exemplary implementations

[0037] In the following, different embodiments of the present invention are described using the following examples: Fig. 1-3 described, wherein identical reference numerals are assigned in the figures to the objects that have identical or similar functions, so that objects with the same reference numerals are interchangeable in different embodiments and their descriptions correspond to each other.

[0038] It should be noted that in the following, DC and AC voltages applied to the same terminal of the circuit will be given the same reference symbols, even though the magnitude, phase and polarity of the voltages may vary depending on the operating state of the circuit. Power converter circuit according to Figure 1

[0039] Fig. Figure 1 shows a block diagram of a power converter circuit 40 with three terminals, namely the AC terminal 24, the first DC terminal 18 and the second DC terminal 32. Furthermore, the power converter circuit 40 has a bridge circuit 42 between the second DC terminal 32 and a choke arrangement 44, which in turn is connected via a switching network 46 to the AC terminal 24 and the first DC terminal 18.

[0040] The bridge circuit 42 comprises three half-bridges 42a, 42b, and 42c, which are connected via a first common potential junction 48a to the first terminal 32a of the DC voltage terminal 32 and via a second common potential junction 48b to the second terminal 32b of the second DC voltage terminal 32. The choke arrangement 44 has three chokes 44a, 44b, and 44c, the first terminals of which are each connected to a central node 45a, 45b, and 45c of the corresponding half-bridge 42a, 42b, and 42c. The respective second terminals of the three chokes 44a, 44b and 44c are connected in a switchable manner via a switching network 46 to the AC voltage terminal 24, which has three phase terminals 24a, 24b and 24c, and to the first DC voltage terminal 18, which includes the terminal 18a for the first pole and the terminal 18b for the second pole.In addition, a ground connection 47 is provided, which couples the switching network 46 with the second common potential guide 48b of the bridge circuit 42 via a node 45d.

[0041] Furthermore, two switching states are symbolically represented for the switching network 46. A first switching state 50 enables the conversion of three-phase alternating voltage V. 24a , V 24b and V 24c in DC voltage V 32ab at the second DC voltage terminal 32 or vice versa. A second switching state 52 enables the conversion between single-phase AC voltage V 24ab at the first phase terminal 24a and at the second phase terminal 24b of the AC voltage terminal 24 and DC voltage V 18ab at the first DC voltage terminal 18 and, preferably simultaneously, the conversion between DC voltage V 32ab at the second DC voltage terminal 32 and DC voltage V 18abat the first DC terminal 18.

[0042] Having described the structure of the power converter circuit 40 above, the following section discusses in detail the operation of this power converter circuit.

[0043] The converter circuit 40 is configured to switch the switching network 46 into at least two of its five or more switching states, namely, for example, a first or second switching state. Optionally, the converter circuit 40 can be configured to switch the switching network 46 into a third, fourth, fifth, and / or further switching state. The switching states are described below by way of example.

[0044] The first switching state 50 serves for three-phase AC-to-DC conversion or three-phase DC-to-AC conversion. Here, the three chokes 44a, 44b, and 44c are coupled via the switching network 46 to three different phase connections 24a, 24b, and 24c of the AC terminal 24 in order to appropriately couple the bridge circuit 42 based on a DC voltage V applied to the second DC terminal 32. 32ab an alternating voltage V at the AC voltage terminal 24 or at the phase terminals 24a, 24b and 24c 24a , V 24b and V 24c to be provided with three phases or based on an alternating voltage V applied to the AC voltage terminal 24 24a , V 24b and V 24c with three phases at the second DC voltage terminal 32 a DC voltage V 32abto provide between the first pole 32a and the second pole 32b. In this first switching state 50, the conversion of alternating voltage V takes place. 24a , V 24b and V 24c with the three phases in DC voltage V 32ab via the three chokes 44a, 44b and 44c by a suitable coupling of the three half-bridges 42a, 42b and 42c or by suitable switching of switching components in the half-bridges 42a, 42b and 42c. Suitable coupling, for example in AC-DC conversion, means such a timing control of the half-bridges 42a, 42b and 42c, such that positive half-waves of the three phases present at the phase terminals 24a, 24b and 24c are coupled to the first common potential junction 48a, while the negative half-waves of the three phases at the phase terminals 24a, 24b and 24c are coupled to the second common potential junction 48b.

[0045] The power converter circuit 40 is designed to put the switching network 46 into the second switching state 52, which serves for simultaneous DC-DC conversion and AC-DC conversion or DC-AC conversion, and in which the first choke 44a is coupled via the switching network 46 to one of the phase terminals, e.g. the phase terminal 24a, of the AC terminal 24, in order to generate a DC voltage V applied to the second DC terminal 32. 32ab at the AC voltage terminal 24 - or more precisely at the phase terminal 24a - the single-phase AC voltage V 24ab to provide or based on the single-phase alternating voltage V applied to phase terminal 24a 24ab A DC voltage V is applied to the second DC terminal 32. 32abto provide. Since the power converter circuit 40 of this embodiment does not necessarily have a neutral conductor connection, such as an earth, against which an alternating voltage V is applied. 24ab The second choke 44b is coupled to the second phase terminal 24b via the switching network 46 if necessary, but not necessarily, to generate an alternating voltage V. 24abbetween the first phase terminal 24a and the second phase terminal 24b, or to tap into the power supply. The converter circuit 40 is designed to control the half-bridges 42a, 42b, and 42c in such a way that, through the interaction of the half-bridges 42a and, if applicable, 42b with the inductors 42a and, if applicable, 42b, rectification or alternating current is achieved, whereby, if necessary, a voltage increase or decrease by at least 50% of the output value, i.e., an increase or decrease in the magnitude of the DC voltage V, is also achieved. 32ab compared to the effective value V 24ab , can take place.

[0046] In the second switching state 52, parallel to the AC-DC conversion takes place, which includes the provision of a DC voltage V 32ab based on an alternating voltage V 24ab as well as, alternatively, a provision of an alternating voltage V 24ab based on a DC voltage V 32abThis is understood to be a DC-DC conversion: Here, another choke, i.e., one of the chokes 44a, 44b, and 44c, which in the first switching state are connected between the bridge circuit 42 and the AC terminal 24, such as choke 44c, is coupled via the switching network 46 to the first DC terminal 18 – or more precisely to the first pole 18a of the DC terminal 18 – in order to generate a DC voltage V applied to the second DC terminal 32 between poles 32a and 32b. 32ab A DC voltage V is applied at the first DC voltage terminal 18 between poles 18a and 18b. 18ab to provide or based on a DC voltage V applied to the first DC terminal 18 18ab A DC voltage V is applied to the second DC terminal 32. 32abto provide. In this DC-to-DC conversion, terminal 18a is connected via the choke 44c to the bridge circuit 42c at the center node 45c of the bridge circuit 42c, while the second terminal 18b of the first DC connection 18 is connected, for example, directly or by means of a switch via the ground connection 47 to the second common potential 48b of the bridge circuit 42 and thus also to the second terminal 32b of the second DC connection 32. In this DC-to-DC conversion, or in the simultaneously occurring AC-to-DC or DC-to-AC conversion, an increase or reduction of a voltage by, for example, at least 10% of the output value can also be made possible, i.e., an increase or decrease in the magnitude of the DC voltage V. 18ab compared to the magnitude of the DC voltage V 32abby at least 10% or more. This is achieved by stepping down or stepping up the signal through appropriate control of the bridge circuit 42 or the half-bridges 42c.

[0047] The following describes optional extensions to the basic functionality of the power converter circuit 40, which make it possible to achieve a significantly increased range of functions with comparatively little additional effort.

[0048] The power converter circuit 40 is optionally designed to put the switching network 46 into a third switching state, which serves to convert single-phase AC voltage into DC voltage V 32abor vice versa. In the third switching state, in which one of the three chokes 44a, 44b or 44c is coupled via the switching network 46 to one of the phase terminals 24a, 24b or 24c of the AC voltage terminal 24, the converter circuit 40 is configured to convert, based on a DC voltage V applied to the second DC voltage terminal 32, 32ab A single-phase alternating voltage V is applied to the AC voltage terminal 24. 24ab to provide or based on a single-phase alternating voltage V applied to the AC voltage terminal 24 24ab A DC voltage V is applied to the second DC terminal 32. 32ab to provide. Analogous to the second switching state 52, there are at least two alternative possibilities for how a single-phase alternating voltage V can be provided. 24awhich can be applied or tapped via the phase connection 24a: One possibility is to galvanically couple a neutral conductor or return conductor, such as an earth, to the bridge circuit 42 or an intermediate voltage node in order to apply a single-phase AC voltage V to the neutral conductor. 24a to tap or provide at phase terminal 24a; in this case, it is sufficient that only the first choke 44a is coupled to the first phase terminal 24a via the switching network 46 at the bridge circuit 44. According to a second possibility, in this embodiment, if the neutral conductor is not statically coupled to the bridge circuit 44 or an associated intermediate voltage node, the second choke 44b is coupled to the second phase terminal 24b via the switching network 46, if necessary, but not necessarily, in order to generate a single-phase AC voltage V. 24abto provide or tap between the first phase terminal 24a and the second phase terminal 24b. In other words, this third switching state represents an analogous switching state to the second switching state 52, except that no DC-DC conversion takes place between the second DC terminal 32 and the first DC terminal 18.

[0049] Furthermore, the power converter circuit 40 can optionally be configured to put the switching network 46 into a fourth switching state, which serves to provide split-phase AC voltages V 24ab and V 24cb in DC voltage V 32abor vice versa. In the fourth switching state, the switching network 46 is configured to couple at least two of the three chokes, e.g., chokes 44a and 44c, to two different phase connections 24a and 24c of the AC voltage input. This special configuration between two AC voltage phases that are offset by 180° is called split-phase or split phase. In this fourth switching state, the AC voltage input 24 is coupled to the bridge circuit 42 via the switching network 46 and the two chokes 44a and 44c. Here again, analogous to the second and third switching states 52, there are at least two alternative possibilities with respect to which neutral conductor the two split-phase AC voltages V are connected. 24ab and V 24cbThe phase connections 24a and 24c can be applied or tapped: One possibility is again a coupling of the neutral conductor, for example, to the bridge circuit 42 or an intermediate voltage node, against which the two split-phase AC voltages V are connected. 24ab and V 24cb The voltage can be tapped or provided at the phase terminals 24a and 24b; it is sufficient that only the first and third chokes 44a and 44c are connected to the first and third phase terminals 24a and 24c by means of the switching network 46. By suitable circuitry and control of the bridge circuit 42, a DC voltage V is thus generated based on a DC voltage V applied to the second DC terminal 32. 32ab at the AC voltage terminal 24, or more precisely at the phase terminals 24a and 24c, two AC voltages V 24ab and V 24cbprovided or based on two alternating voltages V applied to the two phase terminals 24a and 24c (typically out of phase). 24ab and V 24cb A DC voltage V is applied to the second DC terminal 32. 32ab provided. According to a second possibility, in this embodiment, if the neutral conductor connection is not statically coupled to the bridge circuit 42 or an associated intermediate voltage node, a further choke, namely the second choke 44b, is coupled to the second phase connection 24b via the switching network 46, if necessary, but not necessarily, in order to supply the split-phase AC voltages V 24ab and V 24cbto provide or tap between the first phase terminal 24a and the second phase terminal 24b and between the third phase terminal 24c and the second phase terminal 24b, wherein the second phase terminal 24b serves as an “artificial” neutral terminal.

[0050] Furthermore, the converter circuit 40 can optionally be configured to put the switching network 46 into a fifth switching state, which serves for DC-to-DC conversion. In this fifth switching state, the switching network 46 couples one of the three inductors, e.g., the third inductor 44c, via the switching network 46 to the first DC input 18, in order to generate a DC voltage V based on the DC voltage V applied to the second DC input 32. 32ab A DC voltage V is applied to the first DC terminal. 18ab to provide or based on a DC voltage V applied to the first DC terminal 1818ab A DC voltage V is applied to the second DC terminal 32. 32ab To provide a DC-to-DC conversion, a connection is established between the second poles of the DC terminals, namely between the second pole 18b of the first DC terminal 18 and the second pole 32b of the second DC terminal 32, via node 45d and the second common potential path 48b of the bridge circuit 42, via the ground connection 47, which may optionally include a switch. In this DC-to-DC conversion, which is achieved by suitable control of the bridge circuit 42, a voltage change to a higher or lower voltage level, i.e., an increase or decrease in the magnitude of the DC voltage V, can be performed analogously to the DC-to-DC conversion of the second switching state 52. 18ab compared to the magnitude of the DC voltage V 32abfor example, by at least 10%, through a downward or upward conversion.

[0051] As mentioned above, it is possible for the second, third, and fourth switching states from the coupling of the second phase terminal 24b, against which the alternating voltages V 24a , V 24b and V 24cFor example, if no other neutral conductor is available, or if one cannot be tapped or provided, the connection to the choke 44b or the bridge circuit 42 can be omitted, and instead a neutral conductor or ground connection for the converter circuit 40 can be provided, against which the single-phase or split-phase AC voltage can be tapped or provided. In this case, in the second switching state 52, the third switching state, and the fourth switching state, a neutral conductor or ground connection would be coupled to the bridge circuit 42, for example, by means of a node between two capacitors that can be electrically located between the first and second potential leads 48a and 48b (and, if necessary, the converter circuit 40 would also be galvanically coupled in this way). Examples of embodiments according to Figure 2

[0052] Fig. Figure 2a shows a circuit diagram of a power converter circuit 60 according to an embodiment of the invention. The structure of the power converter circuit 60 is essentially the same as that of the power converter circuit 40.

[0053] The power converter circuit 60 has three terminals: the AC terminal 24, the first DC terminal 18, and the second DC terminal 32. The power converter circuit 60 comprises a series connection of the bridge circuit 42, which is connected to the second DC terminal 32, the choke arrangement 44, and the switching network 46, the switching network 46 being connected to both the AC terminal 24 and the first DC terminal 18.

[0054] The bridge circuit 42 consists of three half-bridges 42a, 42b, and 42c, each connected in parallel to the other between the first common potential path 48a and the second common potential path 48b. The common potential path 48a of the bridge circuit 42 serves to connect the bridge circuit 42 to the first terminal 32a of the DC voltage terminal 32, and the second common potential path 48b serves to connect the bridge circuit 42 to the second terminal 32b. In this embodiment, the half-bridges 42a, 42b, and 42c are each implemented by at least two bridge switches: two first bridge switches 42a_1 and 42a_2 in the first half-bridge 42a, two second bridge switches 42b_1 and 42b_2 in the second half-bridge 42b, and two third bridge switches 42c_1 and 42c_2 in the third half-bridge 42c. These bridge switches 42a_1 or 42a_2, 42b_1 or42b_2 and 42c_1 and 42c_2 can, for example, be formed from semiconductor elements and may also be controllable by means of logic (not shown). Between the bridge switches 42a_1 and 42a_2, 42b_1 and 42b_2, and 42c_1 and 42c_2, the center nodes 45a, 45b, and 45c are provided, via which the chokes 44a, 44b, and 44c of the choke arrangement 44 are coupled on a first side or are coupled to their first terminals. The choke 44a is coupled via the center node 45a of the half-bridge 42a, the choke 44b via the center node 45b of the half-bridge 42b, and the choke 44c via the center node 45c of the half-bridge 42c.

[0055] The choke arrangement 44 with the three chokes 44a, 44b and 44c is connected on a second side, i.e. on the side of the second terminals of the respective chokes 44a, 44b and 44c, in a switchable manner to the AC voltage terminal 24 via a switch arrangement 62 and a mains switch 66a connected in series to the switch arrangement 62. The switch 62a of the switch arrangement 62 connects the choke 44a to the mains switch 66a and thus, via the mains switch 66a, to the first phase terminal 24a, the switch 62b of the switch arrangement 62 connects the choke 44b to the mains switch 66a and thus, via the mains switch 66a, to the second phase terminal 24b, and the switch 62c of the switch arrangement 62 connects the choke 44c to the mains switch 66a and thus, via the mains switch 66a, to the third phase terminal 24c.Switches 62a, 62b, and 62c are configured, depending on their switching state, to either connect all three chokes 44a, 44b, and 44c to the three phase terminals 24a, 24b, and 24c, or to connect a specific subset of the three chokes (e.g., chokes 44a and 44c) to a specific subset of the three phase terminals (e.g., phase terminals 24a and 24c), or to disconnect all three chokes 44a, 44b, and 44c from the AC terminal 24. The mains switch 66a simultaneously connects or disconnects all three phase terminals 24a, 24b, and 24c to or from the three switches 62a, 62b, and 62c.

[0056] The choke assembly 44 is also connected on its second side, via a switch assembly 64, to the first terminal 18a of the first DC voltage connection 18, such that the first choke 44a can be connected to terminal 18a via the first switch 64a of the switch assembly 64, or so that the second choke 44b can be connected to terminal 18a via the second switch 64b of the switch assembly 64, and or so that the third choke 44c can be connected to the first terminal 18a via the third switch 64c of the switch assembly 64. The switch assembly 62 is configured to connect or disconnect all of the three chokes 44a, 44b, and 44c, or a specific subset of the three chokes, for example, only the third choke 44c, from the first terminal 18a of the first DC voltage connection 18.In addition, the switching network 46 includes another switch 65 for the ground connection 47, with which the second common potential path 48b of the bridge circuit 42 can be coupled via the node 45d to the second pole 18b of the first DC voltage connection 18.

[0057] For each of the phase connections 24a, 24b, and 24c, a capacitor 68a, 68b, and 68c is provided. The three capacitors 68a, 68b, and 68c, or mains capacitors, of a filter arrangement 68 can be connected on a first side to a neutral conductor via a neutral terminal 24d by means of a switch 66b. On a second side of the filter arrangement 68, the capacitors 68a, 68b, and 68c are connected via the mains switch 66a to their respective assigned phase connections 24a, 24b, and 24c, or via the switches 62a, 62b, and 62c to the chokes 44a, 44b, and 44c. Alternatively, it is also possible that the filter arrangement 68 is not formed by the three capacitors 68a, 68b and 68c, but for example by resistors or other electronic components or by a combination of electronic components with a topology that enables the filtering of an alternating voltage or a three-phase alternating voltage.

[0058] Furthermore, the power converter circuit 60 includes a DC-DC converter 70, which is connected between the second DC terminal 32 and the bridge circuit 42, such that the DC-DC converter 70 is connected on one side to the two potential leads 48a and 48b and on the other side to the two poles 32a and 32b. A DC link capacitor 72, which can consist, for example, of two capacitors connected in series or a supercapacitor, is provided between the first and second potential leads 48a, 48b. An additional capacitor 74 for the first DC terminal 18 is provided between the first pole 18a and the second pole 18b of the DC terminal 18, whereby the capacitor 74 can also be implemented as a supercapacitor.

[0059] The following section describes the operation of the power converter circuit 60.

[0060] The basic operating principle of the power converter circuit 60 corresponds to that of the power converter circuit 40. DC-DC conversion, rectification (AC to DC), and AC-DC conversion are performed via the three inductors 44a, 44b, and 44c, as well as via the half-bridge circuit 42, with appropriate control of the bridge switches 42a_1, 42a_2, 42b_1, 42b_2, 42c_1, and 42c_2. The control of the bridge switches is achieved via a control circuit or logic (not shown) and depends on the specific type of energy conversion, which is set via the individual switching states. The control of the half-bridges 42a, 42b, and 42c is also typically dependent on the frequency of the AC voltage V. 24a , V 24b and V 24c , the currents and voltages of the alternating current V 24a , V 24b and V 24cat the AC voltage terminal 24 and the DC voltage V 18ab at the first DC voltage terminal 18 and the DC voltage V 32ab The second DC voltage connection 32 is selected or set. Furthermore, the inductances 44a, 44b and 44c also typically have a significant influence on the design or setting of the control circuit or on the choice of the control circuit for the half-bridges 42a, 42b and 42c.

[0061] The switching states are set via the switching network 46, as in the power converter circuit 40. The five switching states are explained below with reference to the switching combinations in the switching network 46. For each switching state, the closed switches are named, while it is assumed that the switches not mentioned in the switching network 46 are not closed or open.

[0062] In the first switching state 50 for three-phase charging, for example of battery 30, or for three-phase feedback and, if necessary, islanding, the chokes 44a, 44b and 44c are coupled to the three-phase AC voltage connection 24 or the phase connections 24a, 24b and 24c via the closed switches 62a, 62b and 62c and the closed mains switch 66a. During grid feedback of an AC voltage V 24a , V 24b and V 24c The switch 66b is preferably closed in order to filter the regenerated AC voltages V using the neutral conductor connection 24d and the filter arrangement 68 or the network capacitors 68a, 68b and 68c for the respective phases. 24a , V 24b and V 24c to reach.

[0063] In the second switching state 52, the two switches 62a and 62b for coupling the chokes 44a and 44b to the phase terminals 24a and 24b, as well as the mains switch 66a, are closed. Furthermore, the first pole 18a of the first DC voltage terminal 18 is coupled to the bridge circuit 42 via the closed switch 64c and the choke 44c, while the second pole 18b of the first DC voltage terminal 18 is coupled to the bridge circuit 42, or more precisely to the potential guide 48b of the bridge circuit 42, via the switch 65. Analogous to the first switching state 50, in the case of backfeed of AC voltages V 24ab , therefore, if 40 energy is transferred via the AC voltage connection V through the power converter circuit 24ab The switch 66b is used to filter the alternating voltage V 24abclosed. Optionally, the switch 62b could also be open if a neutral conductor connection is connected to the bridge circuit 42, for example between the two series-connected capacitors of the intermediate circuit 72.

[0064] In the third switching state, switches 62a and 62b, as well as the mains switch 66a, are closed, and chokes 44a and 44b are thus connected to the phase terminals 24a and 24b, enabling single-phase charging (or charging based on single-phase AC voltage), for example, of a battery 30. For single-phase feedback, single-phase islanding, or charging, switch 66b is optionally also closed, so that the capacitors 68a and 68b supply the AC voltage V 24abFiltering can be performed using the neutral terminal 24d in a similar manner. Optionally, the switch 62b could also be open if a neutral terminal is connected to the bridge circuit 42, for example between the two series-connected capacitors of the intermediate circuit 72.

[0065] In this embodiment, the fourth switching state serves to connect to a split-phase network for charging or discharging battery 30, or for feedback or islanding. In the fourth switching state, switches 62a, 62b, and 62c, as well as the mains switch 66a, are closed. In this fourth switching state, split-phase feedback is possible, whereby the filter arrangement 68 is then coupled to the neutral conductor terminal 24d via the closed switch 66b and filters the AC voltages V. 24ab and V 24cbis used. This fourth switching state allows for the provision of an island grid or grid feedback in accordance with North American requirements. Optionally, switch 62b could also be open when a neutral conductor is connected to the bridge circuit 42, for example between the two series-connected capacitors of the DC link 72.

[0066] Alternatively, for the first, second, third and fourth switching states, it is also possible for energy to be fed back in via the AC voltage connection 24, without filtering the AC voltages V. 24ab , V 24a , V 24b , V 24c or V 24cb , i.e., with switch 66b open.

[0067] In the fifth switching state, which serves for DC charging, for example of battery 30, or for DC feedback or for providing a DC power supply, switches 64a, 64b, and 64c are closed, thus connecting the first terminal 18a of the first DC connection 18 to the center nodes 45a, 45b, and 45c via the three chokes 44a, 44b, and 44c. In this fifth switching state, the (optional) switch 65 is closed, thus connecting the second terminal 18b of the first DC connection 18 to the second potential-carrying conductor 48b. The use of all three chokes 44a, 44b, and 44c in the fifth switching state enables particularly efficient energy transfer between battery 30 and the first DC connection.

[0068] It is evident to the expert that a changed coupling combination, e.g. a crossed coupling of the three chokes 44a, 44b and 44c to the three phase terminals 24a, 24b and 24c, together with a variation of the individual switch positions in the circuit network 46, would not change the basic operating principle if the respective voltages V are present at the individual terminals 18, 24 and 32 in the respective switching state. 18ab , V 24ab and V 32ab are provided in the respective conversion modes. An example of this is the AC-DC conversion of single-phase AC voltage V. 24bc , which is applied between the two phase terminals 24b and 24c, in DC voltage V 32abat the second DC voltage terminal 32. This operating principle for single-phase AC-DC conversion, which corresponds to the operating principle described above in the third circuit state, could, for example, be achieved by coupling the chokes 44b and 44c via the switches 62b and 62c together with the mains switch 66a to the two phase terminals 24b and 24c.

[0069] The in Fig. The embodiment discussed in 2a is preferably used in a device with separate power electronics for the drive conversion, or optionally uses separate power electronics for the drive conversion, and provides additional power electronics as a replacement for a charger located in a vehicle, which is also referred to as an onboard charger. Such a power converter circuit 60 is advantageous because the standards for feeding power into the public grid are met, or because compliance with the standards is possible with comparatively little effort in the case of grid feedback, and an improvement in efficiency is achieved, or can be achieved, by optimally optimizing the bridge circuits 42a, 42b and 42c (power electronics) and the chokes 44a, 44b and 44c for the bidirectional conversion of DC voltage to DC voltage and of DC voltage to AC voltage, respectively.Conversely, the corresponding power outputs are designed or are designed accordingly. A further advantage is that, in this embodiment and when using additional power electronics for the drive conversion, simultaneous drive operation and charging operation are possible, e.g., by a DC voltage source 20 attached to the vehicle, such as an inductive energy transformer, a solar cell or fuel cell, or an AC voltage source 26, such as a three-phase alternator coupled to an auxiliary motor.

[0070] Fig. Figure 2b shows a power converter circuit 80, which uses or includes the power electronics for drive conversion. The topology of the power converter circuit 80 is fundamentally the same as that of the power converter circuit 60, except that the switching network 46 comprises three changeover switches 82a, 82b, and 82c instead of switches 62a, 62b, and 62c. Consequently, the power converter circuit 80 is configured to couple the three phases 24a, 24b, and 24c of the AC voltage connection 24 to the inductors 44a, 44b, and 44c in a first switching position of the changeover switches 82a, 82b, and 82c, and to couple a single-phase or three-phase electric machine (E-machine) 84 to the inductors 44a, 44b, and 44c in a second switching position of the changeover switches 82a, 82b, and 82c.Furthermore, it should be noted that the three changeover switches 82a, 82b and 82c may optionally include more than two switch positions in order to allow the chokes 44a, 44b and 44c to be disconnected in a third switch position from both the electric motor 84 and the three phase terminals 24a, 24b and 24c of the AC voltage terminal 24.

[0071] In drive mode, the electric machine is powered by alternating current V 84a , V 84b and V 84c either single-phase or three-phase based on a DC voltage V 32ab The second DC voltage connection 32 is supplied. The AC voltages for supplying the electric motor 84 are provided in the same way as the AC voltages V. 24a , V 24b and V 24c, when the converter circuit 60 or the converter circuit 80 feeds energy into or back into the AC grid 26. In generator mode, the electric machine 84 provides single-phase or three-phase AC voltages V 84ab , V 84a , V 84b and / or V 84c ready, which via the three chokes 44a, 44b and 44c as well as the bridge circuit 42 in DC voltage V 32ab The current is converted at the second DC terminal 32. It is advantageous that the inductors 44a, 44b, and 44c, which are connected in series with the motor windings of the electric motor 84, can smooth the motor current during drive operation. For example, in single-phase operation of the electric motor 84, a specific subset of the chokes 44a, 44b, and 44c are coupled to the electric motor 84 via the changeover switches 82a and 82b, namely, for example, chokes 44a and 44b.

[0072] Alternatively or optionally, in another switch position of the three changeover switches 82a, 82b and 82c, it is possible to connect the electric machine 84 single-phase or three-phase to the AC voltage connection 24 or to the three phase connections 24a, 24b and 24c, in order to operate on the basis of the AC voltage V 84a , V 84b and V 84c an alternating voltage V 24a , V 24b and V 24c or based on alternating voltage V 84ab an alternating voltage V 24ab to provide. This alternative would, for example, allow the coupling of a diesel generator to feed AC voltage back into the AC power grid.

[0073] Another alternative, besides the one mentioned above, would be to connect the electric motor 84 single-phase or three-phase to the AC voltage terminal 24 and simultaneously to the chokes 44a, 44b and 44c in another switch position of the three changeover switches 82a, 82b and 82c, in order to generate a voltage based on the AC voltage V. 84a , V 84b and V 84c an alternating voltage V 24a , V 24b and V 24c or based on alternating voltage V 84ab an alternating voltage V 24ab to provide and simultaneously based on alternating current V 84a , V 84b and V 84c or the alternating voltage V 84ab a DC voltage V 32ab at the DC voltage terminal 32 and / or a DC voltage V 18abto be provided at the DC connection 18. This alternative would also, for example, allow the coupling of a diesel generator for feeding AC voltage back into the AC grid while simultaneously charging a battery.

[0074] Alternatively or optionally, in single-phase operation of the E-machine 84, a conversion, for example of a DC voltage V, can also be carried out simultaneously with motor operation or generator operation of the E-machine 84. 32ab at the second DC voltage terminal 32 into a DC voltage V 18ab at the first DC voltage terminal 18, in analogy to the second switching state 52. Application scenarios according to Figure 3

[0075] The following describes various application scenarios for the 40 and 60 power converter circuits based on the Fig. 3a to 3d are described, with different circuit configurations depending on the application scenario.

[0076] Fig. Figure 3a shows a simplified diagram of a power converter circuit 90, which includes a DC-DC converter 70 and a multifunctional power converter unit 92, wherein the multifunctional power converter unit 92 comprises the inductors 44, the bridge circuit 42, and the switching network 46. The DC-DC converter 70 has a second DC terminal 32, to which the battery 30 is connected with a DC voltage V. 32ab The battery 30 can be part of the power converter circuit 90 or be external. The AC voltage terminal 24 with the three phase terminals 24a, 24b and 24c is connected to the AC voltage network 26 and can thus supply three-phase AC voltage V. 24a , V 24b and V 24c obtain or provide. The first DC voltage connection 18 is connected to a DC voltage network 20 or DC voltage storage with a DC voltage V. 18ab tied together.

[0077] The first switching state 50 (three-phase battery charging or three-phase AC feedback) and the fifth switching state (DC charging) are explained below using the converter circuit 90. Battery 30 can be charged either three-phase via the AC network 26 or via the DC network 20, e.g., by means of an inductive energy transformer. Feedback is possible either three-phase into the AC network 26 or into the DC network 20, or e.g., into a DC energy storage device such as a supercapacitor. Furthermore, a three-phase island grid, which operates autonomously and in parallel with the grid, can be set up. In this case, however, active and reactive power are only available for symmetrical loads. In comparison to the converter device 10 from Fig. In the illustrated embodiment, the multifunctional power converter unit 92 replaces the converters 12 and 14.

[0078] Fig. Figure 3b shows a simplified representation of a power converter circuit 94, which is analogous to power converter circuit 90 of the Fig. 3a comprises the multifunctional power converter unit 92 and the DC-DC converter 70. In this embodiment, unlike the one in Fig. 3a shows an embodiment of an alternating voltage network 26 with a single-phase alternating voltage V 24ab The DC network 20 is connected to the converter circuit 94 via the two phase connections 24a and 24b. In this embodiment, the DC network 20 is connected according to... Fig. 3b, as in the one in Fig. 3a shown embodiment, connected to the first DC voltage terminal 18 of the converter circuit 94 and the battery 30 to the second DC voltage terminal 32.

[0079] This embodiment explains the second switching state 52 and the third switching state, in which the battery 30 is charged single-phase via the AC voltage network 26; simultaneously, in the second switching state 52, charging is carried out using a DC voltage V 18ab from the DC network 20, so that, for example, energy from the AC network 26 and energy from the DC network 20 can be stored in the battery 30 simultaneously. Likewise, charging the battery 30 via the AC network 26 is possible while simultaneously feeding back a DC voltage V. 18ab possible into the DC network 20.

[0080] Single-phase feedback into the AC network 26 and / or simultaneously into the DC network 20 or a DC energy storage device, e.g., a supercapacitor, is possible. Furthermore, single-phase feedback into the AC network 26 is also possible while simultaneously charging the battery 30 via the DC network 20. The converter circuit 94 can provide a DC network 20, a DC power supply, or a single-phase island network 26, which can operate autonomously and in parallel with the grid. Active and reactive power is provided to the AC network 26 as required.

[0081] These described application scenarios of the power converter circuits 90 and 94 can, for example, be used to charge the battery 30 of an electric vehicle using a DC voltage V 18abfrom solar cells or from a DC network or from an inductive energy transformer connected to the DC voltage terminal 18, and simultaneously for power increase by means of a single-phase AC voltage V 24ab to charge via the AC voltage connection 24, which corresponds to the second switching state. If the DC voltage V 18ab If the power from the solar cells is no longer sufficient, it could switch to the first switching state, so that the battery 30 with three-phase alternating voltage V 24a , V 24b and V 24c is charged. Such a switchable power converter circuit enables, with a small number of components, charging on the one hand using solar power or current from an inductive energy transformer and single-phase alternating current, or on the other hand, faster charging using three-phase alternating current.

[0082] Fig. Figure 3c shows a simplified representation of a power converter circuit 96, which corresponds to the power converter circuit 90 and comprises the multifunctional power converter unit 92 and the DC-to-DC converter 70. The first DC voltage terminal 18 is connected to the DC network 20 with a DC voltage V. 18ab connected and the battery 30 with the DC voltage V is connected to the second DC voltage connection 32 32ab connected. An AC network 26 with a split phase, also called split phase, is connected to the AC terminal 24, i.e. the first phase of the AC network 26 is connected to the converter circuit 94 via the first phase terminal 24a and the second phase rotated by 180° via the third phase terminal 24c, while the “second pole” of the AC network 26, e.g. the neutral conductor, is connected to the second phase terminal 24b.

[0083] In this embodiment, the multifunctional power converter unit 92, and in particular the switching network 46, is in the fourth or fifth switching state. Here, the battery 30 can be charged either via the AC network 26 with the "split-phase" network configuration or via the DC network 20. Conversely, energy can be fed back into the AC network 26 or the DC network 20, or into a DC energy storage device such as a supercapacitor, via the split phases. An island grid with the "split-phase" network configuration can be formed. This system is capable of handling unbalanced loads and provides active and reactive power.

[0084] Fig.Figure 3d shows a power converter circuit 98, which corresponds to the power converter circuit 90, except that the electric motor 84 is additionally coupled to the multifunctional power converter unit 92. In this embodiment, the multifunctional power converter unit 92 can drive the electric motor 84, for example, an electric motor, or draw AC voltage from the electric motor 84, for example, a generator. The electric motor 84 can be operated single-phase or three-phase. Depending on the respective switching state of the switching network 46 of the multifunctional power converter unit 92, an AC voltage network 26 can be coupled either single-phase, three-phase, or split-phase. Furthermore, the DC voltages V 18ab and V 32ab They can be connected via the respective DC terminals 18 and 32.

[0085] Although some aspects have been described in connection with a device, it is understood that these aspects also constitute a description of the corresponding process, so that a block or component of a device can also be understood as a corresponding process step or as a feature of a process step. Similarly, aspects described in connection with or as a process step also constitute a description of a corresponding block, detail, or feature of a corresponding device.

[0086] In summary, the innovation in some embodiments lies in the use of the same power semiconductors 42a_1, 42a_2, 42b_1, 42b_2, 42c_1 and 42c_2 (bridge switches) and inductors 44a, 44b and 44c (chokes) for all energy flow directions and voltage waveforms. Only the same semiconductors or chokes are used for DC / DC, AC / DC and DC / AC conversion, and AC sources can also be used without an additional conversion unit. As a result, the invention offers the possibility of saving on components. In other applications, only modularly connected components have been used to date, which, however, do not offer such a good compromise between cost, space requirements, weight, and functionality.

[0087] A switching device (switching network 46) is provided for the use of the same components. An internal switching device (switching network 46) currently consists of switches 62a, 62b, and 62c, as well as switches 64a, 64b, and 64c. Even if this switching device or switch topology (switching network 46) is provided externally, it does not change the fundamental idea or core of the invention. The use of inductors connected in series with the motor windings smooths the motor current. However, the inductors primarily serve to comply with the standards for feeding power into the public grid, so that, in this invention, motor windings not designed for such use may be employed.Exemplary embodiments according to the present invention therefore enable simultaneous and non-simultaneous conversion of the different forms of energy into different energy directions with minimal power electronics.

[0088] A key area of ​​application for the invention lies in the automotive industry, specifically in applications for electric vehicles for charging not only from the public grid but also from a DC power source, such as via inductive power transfer. This measure can reduce costs, space requirements, and weight.

Claims

[1] Power converter circuit (40, 60, 80, 90, 94, 96, 98) with the following features: a bridge circuit (42) with three half-bridges (42a, 42b, 42c); three chokes (44a, 44b, 44c) each connected to a central node (45a, 45b, 45c) of the half-bridges (42a, 42b, 42c); a switching network (46) configured to connect the three chokes (44a, 44b, 44c) in a switchable manner to an AC voltage terminal (24) and a first DC voltage terminal (18); and a second DC voltage connection (32) which is connected to a first common potential path (48a) of the bridge circuit (42) and a second common potential path (48b) of the bridge circuit (42); wherein the power converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to put the switching network (46) into a first switching state (50) in which the three chokes (44a, 44b, 44c) are coupled via the switching network (46) to three different phase terminals (24a, 24b, 24c) of the AC voltage terminal (24) in order to provide grid feedback based on a DC voltage (V) applied to the second DC voltage terminal (32) 32ab ) at the AC voltage terminal (24) an alternating voltage (V 24a , V 24b , V 24c ) to provide, and wherein the converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to operate in the first switching state (50) of the switching network (46) based on an alternating voltage (V) applied to the AC voltage terminal (24). 24a , V 24b , V 24c ) at the second DC voltage terminal (32) a DC voltage (V 32ab ) to provide, and wherein the converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to put the switching network (46) into a second switching state (52) in which a first choke (44a) of the three chokes (44a, 44b, 44c) is coupled via the switching network (46) to one of the phase terminals (24a, 24b, 24c) of the AC voltage terminal (24) in order to provide grid feedback based on a DC voltage (V) applied to the second DC voltage terminal (32) 32ab ) at the AC voltage terminal (24) an alternating voltage (V 24ab ) to provide, and in which another of the three chokes (44a, 44b, 44c) is coupled via the switching network (46) to the first DC voltage terminal (18) to provide, based on a DC voltage (V) applied to the second DC voltage terminal (32) 32ab ) at the first DC voltage terminal (18) a DC voltage (V 18ab) to provide or based on a DC voltage (V) applied to the first DC terminal (18) 18ab ) at the second DC voltage terminal (32) a DC voltage (V 32ab ) to provide, and wherein the power converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to operate in the second switching state (52) of the switching network (46) in the opposite direction of energy flow based on an alternating voltage (V) applied to the AC voltage terminal (24). 24ab ) at the second DC voltage terminal (32) a DC voltage (V 32ab ) to provide, and based on a DC voltage (V) applied to the first DC terminal (18) 18ab ) at the second DC voltage terminal (32) a DC voltage (V 32ab ) to provide or based on a DC voltage (V) applied to the second DC terminal (32) 32ab) at the first DC voltage terminal (18) a DC voltage (V 18ab to provide. [2] Power converter circuit (40, 60, 80, 90, 94, 96, 98) according to claim 1, wherein the power converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to put the switching network (46) into a third switching state in which one of the three inductors (44a, 44b, 44c) is coupled via the switching network (46) to one of the three phase terminals (24a, 24b, 24c) of the AC voltage terminal (24) in order to generate a DC voltage (V) applied to the second DC voltage terminal (32) 32ab ) at the AC voltage terminal (24) a single-phase AC voltage (V 24ab ) to provide or based on a single-phase alternating voltage (V) applied to the AC voltage terminal (24) 24ab ) at the second DC voltage terminal (32) a DC voltage (V 32ab) to provide, wherein the first DC voltage connection (18) is decoupled from the bridge circuit (42) in the third switching state. [3] Power converter circuit (40, 60, 80, 90, 94, 96, 98) according to one of claims 1 or 2, wherein the power converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to put the switching network (46) into a fourth switching state in which at least two of the three chokes (44a, 44b, 44c) are coupled via the switching network (46) to at least two different phase terminals (24a, 24c) of the AC voltage terminal (24) in order to generate a DC voltage (V) applied to the second DC voltage terminal (32) 32ab ) at the AC voltage terminal (24) an alternating voltage (V 24ab , V 24cb ) to provide two phases offset by 180° or based on an alternating voltage (V) applied to the AC voltage terminal (24) 24ab , V 24cb) with two phases offset by 180° at the DC voltage terminal (32) a DC voltage (V 32ab ) to provide, wherein the first DC voltage connection (18) is decoupled from the bridge circuit (42) in the fourth switching state. [4] Power converter circuit (40, 60, 80, 90, 94, 96, 98) according to any one of claims 1 to 3, wherein the power converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to put the switching network (46) into a fifth switching state in which at least one of the three chokes (44a, 44b, 44c) is coupled via the switching network (46) to the first DC voltage terminal (18) in order to, based on a DC voltage (V) applied to the second DC voltage terminal (32), 32ab ) at the first DC voltage terminal (18) a DC voltage (V 18ab ) to provide or based on a DC voltage (V) applied to the first DC terminal (18) 18ab) at the second DC voltage terminal (32) a DC voltage (V 32ab ) to provide, wherein the AC voltage connection (24) is decoupled from the bridge circuit (42) in the fifth switching state. [5] Power converter circuit (40, 60, 80, 90, 94, 96, 98) according to any one of claims 1 to 4, wherein the three half-bridges (42a, 42b, 42c) each have at least two bridge switches (42a_1, 42a_2, 42b_1, 42b_2, 42c_1, 42c_2). [6] Power converter circuit (40, 60, 80, 90, 94, 96, 98) according to claim 5, wherein the bridge switches (42a_1, 42a_2, 42b_1, 42b_2, 42c_1, 42c_2) are implemented by semiconductors. [7] Power converter circuit (40, 60, 80, 90, 94, 96, 98) according to one of claims 5 or 6, wherein the power converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to control the bridge switches (42a_1, 42a_2, 42b_1, 42b_2, 42c_1, 42c_2) by means of a logic. [8] Power converter circuit (40, 60, 80, 90, 94, 96, 98) according to any one of claims 1 to 7, wherein the power converter circuit (40, 60, 80, 90, 94, 96, 98) comprises three switches (62a, 62b, 62c) for switchable, selective coupling of the three inductors (44a, 44b, 44c) to the three phase terminals (24a, 24b, 24c) of the AC voltage terminal (24), wherein the switches (62a, 62b, 62c) are configured to selectably either couple all of the three inductors (44a, 44b, 44c) to the three phase terminals (24a, 24b, 24c) or a true subset of the three inductors (44a, 44b, 44c) to couple to a real subset of the three phase terminals (24a, 24b, 24c) or to decouple the three chokes (44a, 44b, 44c) from the three phase terminals (24a, 24b, 24c). [9] Power converter circuit (40, 60, 80, 90, 94, 96, 98) according to any one of claims 1 to 8, wherein the switching network (46) comprises three switches (64a, 64b, 64c) for switchable, selective coupling of the three inductors (44a, 44b, 44c) to the first DC voltage terminal (18), wherein the switches (64a, 64b, 64c) are configured to selectably either couple all of the three inductors (44a, 44b, 44c) to the first DC voltage terminal (18) or a true subset of the three inductors (44a, 44b, 44c) to the first DC voltage terminal (18) or to disconnect the three inductors (44a, 44b, 44c) from the first DC voltage terminal (18). [10] Power converter circuit (40, 60, 80, 90, 94, 96, 98) according to one of claims 1 to 9, wherein the switching network (46) additionally comprises a switch (66b) for switching a neutral conductor via a filter arrangement (68) to the three chokes (44a, 44b, 44c). [11] Power converter circuit (80, 98) according to one of claims 1 to 10, wherein the switching network (46) comprises three changeover switches (82a, 82b, 82c), wherein the power converter circuit (80, 98) is configured to couple the three phase terminals (24a, 24b, 24c) of the AC voltage terminal (24) to the three chokes (44a, 44b, 44c) in a first switching position of the changeover switches (82a, 82b, 82c) and to couple a single-phase or three-phase electric machine (84) to the chokes (44a, 44b, 44c) in a second switching position of the changeover circuit (82a, 82b, 82c) and to connect the single-phase or three-phase electric machine (84) to three phase terminals (24a, 24b, 24c) or to at least one of the three phase terminals (24a, 24b, 24c) of the AC voltage connection (24) and simultaneously to the chokes (44a, 44b, 44c), wherein the electric machine (84) can be operated in drive mode and in generator mode. [12] Power converter circuit (80, 98) according to claim 11, wherein the power converter circuit (80, 98) is configured to couple the three phase connections (24a, 24b, 24c) of the AC voltage connection (24) to the electric machine (84) or to the electric machine (84) and the three chokes (44a, 44b, 44c) in a further switching position of the changeover switches (82a, 82b, 82c). [13] Power converter circuit (40, 60, 80, 90, 94, 96, 98) according to any one of claims 1 to 12, wherein the power converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to supply a DC voltage (V) at the second DC voltage terminal (32) in the first, second, third and / or fourth switching state (50, 52). 32ab ) to provide, the amount of which is at least 10% greater or less than the effective value of an alternating voltage (V) applied to the AC voltage terminal (24).24ab , V 24cb ), or to apply an alternating voltage (V) to the AC voltage terminal (24). 24ab , V 24cb ) to provide, whose RMS value is at least 10% greater or less than the magnitude of a DC voltage (V) applied to the second DC terminal (32). 32ab ). [14] Power converter circuit (40, 60, 80, 90, 94, 96, 98) according to any one of claims 1 to 13, wherein the power converter circuit (40, 60, 80, 90, 94, 96, 98) is configured to supply a DC voltage (V) at the second DC voltage terminal (32) in the second and / or fifth switching state (50, 52). 32ab ) to provide, the amount of which is at least 10% greater or less than the amount of a DC voltage (V) applied to the first DC terminal (18). 18ab ), or to apply a DC voltage (V) to the first DC terminal (18) 18ab) to provide, the amount of which is at least 10% greater or less than the amount of a DC voltage (V) applied to the second DC terminal (32). 32ab ). [15] Power converter circuit (60, 80, 90, 94, 96, 98) according to one of claims 1 to 14, wherein a DC-to-DC converter (70) is provided at the second DC voltage terminal. [16] Power converter circuit (60, 80, 90, 94, 96, 98) according to any one of claims 1 to 15, wherein the power converter circuit (60, 80, 90, 94, 96, 98) is configured to feed back three-phase alternating voltage in the first switching state (50). [17] Method for operating a power converter circuit (40, 60, 80, 90, 94, 96, 98) with a bridge circuit (42) having three half-bridges (42a, 42b, 42c), three inductors (44a, 44b, 44c) each connected to a central node (45a, 45b, 45c) of the half-bridges (42a, 42b, 42c), a switching network (46) configured to connect the three inductors (44a, 44b, 44c) in a switchable manner to an AC terminal (24) and a first DC terminal (18), and a second DC terminal (32) connected to a first common potential (48a) of the bridge circuit (42) and a second common potential (48b) of the bridge circuit (42), the method comprising the following steps includes: Switching the switching network (46) into a first switching state (50) in which the three chokes (44a, 44b, 44c) are coupled via the switching network (46) to three different phase connections (24a, 24b, 24c) of the AC voltage connection (24); wherein in the first switching state (50) based on a DC voltage (V) applied to the second DC voltage terminal (32) 32ab ) for grid feedback at the AC voltage connection (24) an alternating voltage (V 24ab ) is provided, and where, in the first switching state (50) with the opposite direction of energy flow, an alternating voltage (V) applied to the AC voltage terminal (24) 24ab ) at the second DC voltage terminal (32) a DC voltage (V 32ab ) is provided; and Switching the switching network (46) into a second switching state (52) in which a first choke (44a) of the three chokes (44a, 44b, 44c) is coupled via the switching network (46) to one of the phase terminals (24a, 24b, 24c) of the AC voltage terminal (24) and in which another choke of the three chokes (44a, 44b, 44c) is coupled via the switching network (46) to the first DC voltage terminal (18); wherein in the second switching state (52) for mains feedback based on a DC voltage (V) applied to the second DC voltage terminal (32) 32ab ) at the AC voltage terminal (24) an alternating voltage (V 24ab ) is provided, where, in the second switching state (52) with the opposite direction of energy flow, an alternating voltage (V) applied to the AC voltage terminal (24) 24ab ) at the second DC voltage terminal (32) a DC voltage (V 32ab) is provided; and wherein in the second switching state (52) based on a DC voltage (V) applied to the second DC voltage terminal (32) 32ab ) at the first DC voltage terminal (18) a DC voltage (V 18ab ) is provided, and where, in the opposite direction of energy flow, based on a DC voltage (V) applied to the first DC terminal (18), 18ab ) at the second DC voltage terminal (32) a DC voltage (V 32ab ) is provided.

Images