WO2022223386A1

WO2022223386A1 - Power converter circuit

Info

Publication number: WO2022223386A1
Application number: PCT/EP2022/059849
Authority: WO
Inventors: Eckart Hoene
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2021-04-19
Filing date: 2022-04-13
Publication date: 2022-10-27
Also published as: DE102021203875A1; EP4327441A1

Abstract

The invention relates to a converter circuit (10, 10'), comprising the following features: a bridge circuit (20, 20') having at least one half-bridge (20a, 20b, 20c), the bridge circuit (20, 20') being connected to a further electrical component (28, 28') which has a parasitic capacitor (28p1, 28p2); a compensation circuit (30, 50), which is connected in parallel with an assembly (20+28, 20'+28') of the bridge circuit (20, 20') and the further electrical component (28, 28'), the compensation circuit (30, 50) having one or more parallel-connected resonant paths (31a, 31b, 31c), each resonant path (31a, 31b, 31c) having at least one switchable element (32, 32a, 32b), each of the one or more parallel-connected resonant paths (31a, 31b, 31c) being coupled via a resonant inductor (36) to an associated compensation capacitor (42, 42a, 42b, 42c) of the one or more compensation capacitors (42, 42a, 42b, 42c).

Description

converter circuit

description

Embodiments of the present invention relate to a converter circuit, in particular one with a compensation circuit. In accordance with preferred exemplary embodiments, the power converter circuit can be used, for example, in combination with a motor as the electrical component or a transformer as the electrical component. Embodiments of the present invention advantageously enable regenerative common-mode charge reversals.

When power electronic circuits are operated, what are known as common-mode voltages occur, which charge parasitic capacitances and thus generate both losses and electromagnetic interference, so-called common-mode currents.

Circuits for compensating for electromagnetic interference and fault currents are already known in the prior art. For example, reference is made to the patent applications JPH09037593A and DE102017220109A1. DE102017220109A1, for example, relates to a converter circuit with a rectifier, a DC/DC converter and an inverter. Ground current compensation avoids interference. However, the disadvantage of the designs described here are the additional losses that result from the charge reversal of the compensation capacitor and the semiconductors fed from the intermediate circuit. Therefore, there is a need for an improved approach.

The object of the present invention is to create a concept that minimizes interference, in particular interference as a result of charge reversal, and at the same time optimizes the overall efficiency of the circuit.

This object is solved by the subject matter as defined by the independent patent claims.

Embodiments of the present invention provide a power converter circuit with a bridge circuit and a compensation circuit. The bridge circuit includes at least one half-bridge, the bridge circuit being connected to another electrical component, such as an electric motor or a transformer. The further electrical component has one or more parasitic capacitances. The compensation circuit is connected in parallel to an arrangement made up of a bridge circuit and the further electrical component and has one or more resonance paths connected in parallel. Each resonance path has a switchable element. Furthermore, each of the one or more parallel-connected resonance paths is coupled via a resonant inductance to an associated compensation capacitance of the one or more compensation capacitances.

Exemplary embodiments of the present invention are based on the finding that the energy stored in the parasitic capacitances can be recovered by a compensation circuit with a resonance path that includes one or more switchable elements, an inductance and a capacitance. If you consider a power converter circuit with a bridge circuit and another component as the main application, the parasitic capacitances are typically found in the connected component. The connected component can be, for example, a transformer with the capacitances between the primary and secondary sides, or an electric motor, which also has significant parasitic capacitances. The functionality of the actual circuit is not adversely affected by the proposed circuit topology including the compensation circuit. In contrast to the operating principles disclosed in the prior art, the compensation circuit present here has a decisive advantage, namely that the energy flows back and forth between the parasitic capacitances and the compensation capacitors of the compensation circuit. The resonant inductances allow resonant charge reversal, in which only the line losses are lost, but the energy stored in the capacitances is recovered.

As already mentioned, according to exemplary embodiments, the electrical component can be an electric motor. Here, for example, the compensation circuit can be coupled to a protective conductor (PE) or protective earth or the motor housing or the body on one side of the compensation circuit. The coupling can take place, for example, via the compensation capacitor/capacitance already defined above. On the other hand, according to further exemplary embodiments, the compensation circuit can have a common contact point of the arrangement, the bridge circuit itself, a center tap of an intermediate circuit of the bridge circuit or a first or second pole of a DC voltage source or a DC voltage connection which is coupled to the bridge circuit. This then implements the parallel connection of the compensation circuit to the arrangement.

According to a further exemplary embodiment, the electrical component can be a transformer. According to exemplary embodiments, the compensation circuit can then be connected in parallel here in that the compensation circuit is connected on one side to the primary side and on the other side to the secondary side of the transformer.

With regard to the bridge circuit, it should be noted that this can be designed here with a half-bridge, that is, for example, single-phase, but according to further exemplary embodiments, several half-bridges, such as three half-bridges, e.g. B. for a three-phase control of an electric motor or a three-phase grid connection would be conceivable.

In accordance with exemplary embodiments, the compensation circuit has three resonance paths. In accordance with preferred exemplary embodiments, each resonance path is coupled to the arrangement via its own compensation capacitance. In this respect, in this variant, the compensation circuit has at least three compensation capacitances, which are each coupled to one of the three resonance paths on one side. On the other hand, these can have a common contact point with the arrangement, e.g. B. with the protective conductor mentioned above or one side of the transformer tor be coupled. At this point it should be noted that the number of resonance paths can depend on the topology of the bridge circuit and/or can depend on the control of the half-bridges of the bridge circuit. For example, if the half-bridges of a bridge circuit with three half-bridges are driven offset, three resonance paths would be optimal, although other configurations would of course also be conceivable. The background to this is discussed in the explanation of the exemplary embodiments with regard to the activation of the switchable elements of the resonance paths and the switchable elements of the half-bridges.

According to exemplary embodiments, the power converter circuit has a controller which is designed to control the switchable element in the one or more resonance paths in each case in such a way that the switchable element before switching over the respective associated half-bridge is activated. According to exemplary embodiments, the switchable element is activated over a period of time in such a way that resonant charge reversal takes place in equal parts before and after the switching process of the respective associated half-bridge.

According to exemplary embodiments, it can be assumed that the switchable element of the resonance paths is formed, for example, by two switchable elements connected in series for each resonance path. For example, the two switchable elements connected in series can have opposite flow directions. According to a further exemplary embodiment, it would be conceivable for a switchable element with two selective blocking directions to be used. Based on this variant, it would be conceivable, for example, for the resonance recharging to be started by switching on the respective switchable element of the two series-connected switchable elements of a respective resonance path, which in the present operating state picks up a voltage, is switched on, and after Completion of the resonance charge is switched off again.

With regard to the bridge circuit, it should be noted that this has one or more half-bridges, with each half-bridge having at least two further switchable elements, for example. These further half-bridges are driven in accordance with preferred exemplary embodiments, as indicated above. The components of the resonant path are also adapted to the other switchable elements. For example, the switchable elements and the resonance paths and the further switchable elements of the bridge circuit have a comparable size in relation to their switching times. In this case, comparable means that the switching time is the same, for example, or deviates by a maximum of a specific range. For example, the ratio should be 1:1 or a maximum of 1:2 or 2:1 or a maximum of 3:1 or 1:3. This means that the switching time of the switchable elements can be twice or half that of the other switchable elements or can generally be in the range between 0.5 and 2.0 or 0.3 and 3. According to further exemplary embodiments, the size of the compensation capacitances is adapted to the parasitic capacitances. For example, the compensation capacitances essentially correspond to the parasitic capacitances. Here essentially means in a range from 0.5 to 2.0 or in a range from 0.3 to 3 Example between 0.7 and 1.3 times or 0.9 and 1.1 times times, are set, it being clear to the person skilled in the art that the narrower the limit, the better the compensation behavior will be developed. The corresponding dependencies between the values are explained below using a calculation example.

A further exemplary embodiment provides a method for driving the power converter circuit, as explained above. In this case, the switchable elements in the resonant path are activated shortly before switching over a half-bridge of the bridge circuit. According to exemplary embodiments, the activation takes place over a period of time, so that a resonant charge reversal can take place in equal parts before and after the switching process of the respective half-bridge. According to further exemplary embodiments, the control is carried out in such a way that a resonance charge reversal is designed in that the respective switchable element of the two series-connected switchable elements of a resonance path is switched, which absorbs a voltage in the present operating state, the same being switched off after the resonance charge reversal .

According to further embodiments, the controller can be computer-implemented. In this respect, control algorithms can be stored on a memory chip, for example, so that they can be executed using a processor.

Further formations are defined in the dependent claims. Exemplary embodiments of the present invention are explained in detail below with reference to the accompanying drawings. Show it:

1 shows a schematic representation of a power converter circuit with a compensation circuit according to a basic exemplary embodiment;

2a shows a schematic representation of a converter circuit with a connected component, in which losses occur as a result of parasitic capacitances, to explain exemplary embodiments;

2b shows a schematic representation of a topology according to the prior art for explaining disadvantages in the prior art; 3 shows a schematic representation of a power converter circuit with a compensation circuit according to extended exemplary embodiments for the application area of an electric motor; and

Fig. 4 is a schematic representation of a power converter circuit according to other extended exemplary embodiments for the field of application Transforma tor.

Before exemplary embodiments of the present invention are explained below with reference to the accompanying drawings, it should be noted that elements and structures that have the same effect are provided with the same reference symbols, so that the description of them can be applied to one another or are interchangeable.

Fig. 1 shows a converter circuit 10 with a bridge circuit 20, which together with an electrical component 28, z. B. an electric motor coupled. Furthermore, the power converter circuit 10 includes a compensation circuit 30. The compensation circuit 30 is coupled to the arrangement comprising the bridge circuit 20 and the electrical component 28 .

The connection between the compensation circuit 30 and the arrangement made up of the elements 20 and 30 can be made, for example, in such a way that a common protective conductor 24 is connected to the compensation circuit. With regard to the coupling between bridge circuit 20 and electrical component 28, it should be noted that the connection is made, for example, via an intermediate tap of a half-bridge 22a of bridge circuit 20 Electric motor are made available. The AC voltage is provided by the half-bridge 22a, starting from a DC voltage present at the two voltage taps 21+ and 21- on the bridge circuit 20. It can be assumed that electrical components, such as the electric motor 28 shown or inductances of the electric motor, have parasitic capacitances 28p which, in combination with the bridge circuit, which is used here, for example, for the alternating direction, lead to charge reversal processes (e.g. causing due to common-mode fluctuations) in these parasitic capacitances 28p. These charge reversal processes are accompanied by a current flow in the converter 20 and are associated with losses. Compensation circuit 30 is now used to compensate for these charge reversal processes. The compensation circuit 30 includes a resonance path 31. The resonance path 31 is connected via a coupling capacitance 38 to the arrangement comprising the elements 20 and 28. The resonance path comprises at least one switchable element 32 and a resonant inductance 36. According to exemplary embodiments, the switchable element 32 can be two series-connected switchable elements which, for example, can be switched. B. have an opposite blocking direction. Alternatively, a switchable element with two reverse directions and two forward directions can also be used. By driving the switchable elements 32 there is a resonant charge reversal, e.g. B. the charges on the capacitor 38a. Although the line losses are lost as a result, the energy stored in the capacitances, in particular the parasitic capacitances 28p, is recovered.

According to exemplary embodiments, the bridge circuit 20 can also have additional half-bridges, as is illustrated here with reference to the half-bridge 22b. Both half bridges 22a and 22b are arranged between the voltage taps 21+ and 21− and can be connected to the electrical component 28 via their center tap, for example. This is a typical topology for coupling or decoupling an AC voltage, with other topologies of course other couplings of the electrical component 28's, z. B. via the DC terminals 21 + and 21 - would be possible.

In this exemplary embodiment, the compensation circuit 30 is coupled via a common contact point 39 which is connected to the protective conductor 24 here. The protective conductor 24 carries, for example, the housing potential and, assuming an electric vehicle, the body potential. However, according to further exemplary embodiments, a coupling of the common contact point 39 to the arrangement or the electrical component 28 is also conceivable. It is important that the compensation circuit 30 is connected in parallel with the arrangement comprising the elements 20 and 28 . In this variant, it is realized, for example, in that the bridge circuit 20 has an intermediate circuit 24 with intermediate circuit capacitors 24k1 and 24k2, the second side of the compensation circuit or here the second side of the resonance path 31a being coupled to an intermediate tap of the intermediate circuit 24. The fact that the compensation circuit 30 is connected on one side to the intermediate circuit 24 or the converter circuit 20 and on the other side with the protective conductor 24 or the component 28, the compensation circuit 30 is connected with respect to the arrangement comprising the components 20 and 28 in parallel.

Of course, according to further exemplary embodiments, the first side of the compensation circuit 30 cannot be coupled via the intermediate circuit 24, but rather directly via the voltage tap 21+ or 21−. All couplings have in common that the compensation circuit 30 is connected to a first side with the bridge circuit 20, while a second side is connected to component 28. Connected here means electrically coupled, directly electrically contacted or galvanically coupled.

According to further exemplary embodiments, the compensation circuit 30 can also have further resonance paths, here using the example of the resonance path 31b. The resonance path 31b is connected to the common contact point 39 via the further compensation capacitance 38b. This contact point 39 is arranged on the second side. A common contact point 37 can also be present on the first side of the compensation circuit 30, which is connected to the optional intermediate circuit 24 in this exemplary embodiment. At this point it should be noted that all elements shown in FIG. 1 are considered optional, whereas conversely this is not a statement to the effect that the elements marked as not dashed are mandatory.

The overall problem with the parasitic capacitances is explained again in detail below with reference to FIGS. 2a and b, an extended exemplary embodiment of the circuit shown here from FIG. 1 then being explained in connection with FIG. Fig. 4 shows the use of the compensation circuit in connection with egg ner further application.

Referring to FIG. 2, an exemplary constellation as the initial situation is explained.

Fig. 2a shows an inverter 20 with three half-bridges 20a-20c, each having two switchable elements 22a and 22b. Each switchable element is connected in parallel with a diode, the reverse direction of the diode being arranged in the opposite direction to the reverse direction of the switchable element. The two switchable elements 22a and 22b have, for example, the same blocking direction. Analogous to the embodiment of FIG. 1, the common potential taps are here 21 + and 21 - designed so that the three Half-bridges 20a-20c are arranged in between. In addition, the inverter has an intermediate circuit capacitor 24 which is arranged between the two potential taps 21+ and 21−. Optionally, each of the two potential taps 21 + and 21 - can be coupled to a protective conductor 24 via a further capacitor 25 , for example. The capacitors are called Y-capacitors 25, for example.

The inverter 20 is connected between a battery 15 on the DC side and a motor 28 on the AC side. The motor 28 is coupled to the intermediate taps of the half-bridges 20a-20c, for example. The intermediate taps are associated with reference numerals 26a-26c. The connection is made, for example, via a shielded cable 27 comprising the components 27a-27d, with 27a, 27b and 27c being assigned to the intermediate taps 26a, 26b and 26c, while 27d is used for the PE conductor 24. 24 or 27d is connected to the engine mass of the engine 28. In addition, the motor has motor inductances, for example, as shown here. For the sake of completeness, it should be pointed out that the battery is connected to the cable 16, here a three-wire cable for the voltage taps 21+ and 21- and the protective conductor 24. All elements such as B. the shielded cable 27, the motor 28 form parasitic capacitances, the parasitic capacitances are particularly problematic where due to potential changes (AC voltage or common mode), it can lead to a current flow. The parasitic capacitances 28p1 in the area of the cable and between the wires 27a or 27b or 27c and the wire 27d and 28p2 between the individual motor phases and the housing are shown here as an example on the motor 28 side.

The three half-bridges 20a-20c switch the voltage and thus charge the parasitic capacities 28p1 and 28p2 of cable 27 and motor 28 against the stator with losses. The resulting current should be closed within the converter to avoid common mode interference in the battery.

There is a first approach to this in the prior art, which is shown in connection with FIG. 2b.

Fig. 2b shows the arrangement of battery 15, battery cable 16, inverter 20, Motorka bel 27 and motor 28. A second converter 40 can be coupled to the converter 20 who the. The second converter 40 is constructed, for example, similarly or identically to the converter 20, with its voltage taps 40+ and 40- for the DC voltage (between which the half-bridges 20a-20c are arranged) connected to the corresponding voltage taps 21+ and 21-. The half-bridges 20a-20c are each connected via their intermediate circuit using a capacitor arrangement 42 to the protective conductor 24. A common potential point 44 is used here. The capacity arrangement 42 includes, for example, a dedicated capacitor 42a-42c for each intermediate circuit tap. This means that the three capacitors 42a, 42b and 42c are connected in parallel and are each connected to an intermediate tap of the half-bridges 20a-20c on one side, while they are connected to the common potential point on the second side.

By using the inverter 40, anti-phase biasing can be induced at the potential point 44 to minimize the interference. To compensate, for example, the second converter 40 is controlled in an inverted manner with the same control signals and thus recharges the compensation capacitors 42a-42c. An optimization of this arrangement 40 is explained below with reference to FIG. Here there is one of the compensation circuit 50 formed by resonance paths 31a, 31b and 31c.

3 shows the converter circuit 10' with the bridge circuit 20, which is arranged between the motor 28 and the battery 15. Cables 16 and 27 are again used. The bridge circuit 20 here in turn has three half-bridges 20a-20c, which are coupled between the potential taps 21+ and 21-. In this exemplary embodiment, an intermediate circuit 24 comprising the series-connected intermediate circuit capacitors 24k1 and 24k2 is also provided.

To compensate, the arrangement of the bridge circuit 20 and the motor 28 is connected in parallel. Overall, it means that, for example, the compensation circuit 50 on the one hand, z. B. via a common potential point 39, connected to the protective conductor 24 and on the other side, z. B. via an intermediate tap of the intermediate circuit 24 (i.e. between the capacitors 24k1 and 24k2), with the bridge circuit 20. Connected in parallel therefore means that the compensation circuit 50 is coupled on one side to a common potential point of the electrical component 28 and on the other side with a common potential point 37 (intermediate tap of the intermediate circuit 24) with the bridge circuit 20.

In this embodiment, the compensation circuit 50 has three resonance paths 31a, 31b and 31c. These three are all connected in parallel, that is, on their first Side connected to the common contact point 37 and connected on the other side via a capacitor array 42 to the common contact point 39. The capacity arrangement 42 includes a separate capacity 42a, 42b and 42c for each resonance path 31a, 31b and 31c. These capacitors 42a, 42b and 42c are approximately as large as the parasitic capacitances 28p1 and 28p2, for example. As shown above, there are three parasitic 28p1 capacitances and three parasitic 28p2 capacitances, namely between a phase connection of the motor or a motor inductance assigned to a phase and the protective conductor 24. Each compensation capacitance 42a, 42b and 42c can therefore be adapted to the individual parasitic capacitances 28p1 and 28p2 per phase, in which case the entirety of the capacitances 42a, 42b and 42c corresponds to the total of the entirety of the capacitances 28p1 and 28p2. At this point it should be noted that essentially, for example, it should be interpreted to the effect that the same order of magnitude (power of ten) should be involved. As already explained above, the same order of magnitude means that the criterion still applies if there is a maximum deviation from one capacity to the other capacity, e.g. B. a maximum of 3 times or a third or z. B. a maximum of 0.5 times or 2 times. In general, this criterion means that the compensation capacitances 42a, 42b and 42c, individually or in total, correspond to 0.3 to 3.0 times or 0.5 to 2.0 times or the 0.9 to 1.1 times the parasitic capacitances 28p1 and 28p2.

With regard to the individual resonance paths 21a, 21b and 21c, it should be pointed out that these are designed in the same way or in the same way in accordance with the exemplary embodiment. Each of these resonance paths therefore has the same components, with the resonance paths 21a-21c being explained below with reference to the resonance path 21a.

The resonance path 21a comprises a switchable element 32, which in this exemplary embodiment is formed by two switchable elements 32a and 32b. These two switchable elements can be semiconductor transistors, for example, which have an opposite forward direction or an opposite blocking direction. Each of these semiconductor transistors of the switchable elements 32a and 32b is bridged by a correspondingly oppositely arranged diode. An inductance 36 is arranged in series with the switchable element 32 in the resonance path 31a. In this exemplary embodiment, this is provided between the switchable element 32 and the compensation capacitance 42a. If the capacitors 42a-42c are recharged in phase opposition to the motor capacitances 28p2 or general parasitic capacitances 28p1 and 28p2, the currents in the converter close and do not become effective as disturbances.

Compared to the embodiment from FIG. 2b, it is advantageous here that the energy flows back and forth between the parasitic capacitances in the compensation capacitors 42a-42c. The resonant inductances 36 for each resonance path 31a-31c permit resonant recharging, in which only the conduction losses are lost, but the energies stored in the capacitances 28p1, 28p2 are recovered. Rather, compensation capacitors 42a, 42b and 42c can be selected in a wide range of capacitances, which can vary from slightly smaller than the parasitic capacitances to larger. With larger capacitances, the dielectric strength of the semiconductors for the switchable elements is somewhat lower. With smaller capacitances, the values of the resonant inductances are larger. In this respect, the capacity 42a (or 42b or 42c) is dimensioned together with the inductance 36 and the switchable elements 32 in the compensation circuit 50 . A sizing example is given below.

Before this dimensioning example is explained, it should also be pointed out that the switchable elements 32 are preferably selected taking into account the switchable elements of the half-bridges 21a, 21b and 21c. The switching speed of the half-bridges 21a, 21b and 21c should roughly correspond to the resonant frequency of the compensation network. Roughly the same again means the same order of magnitude, which means that switching speeds of the element 32 should be between 0.3 and 3 times or 0.5 and 2 times or 0.9 and 1.1 times the resonant frequency of the resonance path or the inductance 36 or the inductance 32 in combination with the parasitic capacitances and capacitances would be conceivable. In other words, this means that the resonant frequency is essentially dependent on the inductance 36 and the parasitic capacitance. In accordance with exemplary embodiments, the resonant element 36 can therefore be dimensioned in relation to the parasitic capacitance.

Assuming, for example, 100 ns semiconductors for the half-bridges, this corresponds to a switching frequency of 10 MHz. For the switchable elements 32 either the same switching speed or a reduced Schaltge speed can be used such. B. a switching speed / resonant frequency of 5 MHz. Whereby it is assumed that in this dimension example the parasitic The capacitances are 1 nanofarad (nF), in which case the capacitances 42a and 42c are dimensioned the same, namely also 1 nF. With such a dimensioning, the inductance 36 would then be designed with 1 pH.

With regard to the switchable elements 32, it should be noted that, as shown here, these can consist of two individual switchable elements 32a and 32b, which are connected in series. This arrangement allows locking in both directions. Alternatively, a switchable element with two blocking directions or two passage directions would also be conceivable, with blocking in both directions again being possible.

According to exemplary embodiments, the switchable elements 32 are activated in such a way that this (ideally) takes place shortly before the switching of the half-bridges 21a-21c (depending on the assignment), with the time (activation time) being selected in accordance with further exemplary embodiments in such a way that the Resonance recharging takes place in equal parts before and after the switching process. According to exemplary embodiments, the resonant charge reversal is started in that the switchable element 32a or 32b of the two series-connected elements 32, which absorbs voltage in the present operating state, is switched on. This is then switched on and switched off after completion of the resonant charge. A current reversal is prevented by the freewheeling diode of the other switchable element 32b or 32a.

In principle, the resonance recharging is most optimal with similar speeds as the switching of the half-bridges. However, the currents then become very high and expensive semiconductors are required. Therefore, according to exemplary embodiments, deviations with regard to the switching times can be permitted, e.g. B. in the range of 0.3 to 3 of the switching time of the semiconductor bridge circuit. According to further exemplary embodiments, damping resistors can be provided for vibrations that occur, in order to shield the system from reality. A possible arrangement of these damping resistors would be in the Y-capacitors, which are provided with the reference numeral 25 (see also the explanation in FIG. 2a).

At this point it should be noted that, according to exemplary embodiments, the resonant circuit 50 is used at the center point tap 37 of the intermediate circuit 24 . Alternatively, coupling to DC+ and DC-, that is, to the voltage taps 21+ and 21-, would also be conceivable. According to exemplary embodiments, the control explained above can take place by means of suitable pulse patterns. When choosing a suitable pulse pattern, it is possible to reduce the number of resonant circuits (here three, e.g. to two). In general, it should be noted that the number of resonant circuits 31a-31c can correspond, for example, to the number of half-bridges 20a-20c, with more or fewer resonant circuits obviously also being possible, which are then optimized by appropriate controls.

A further application of the compensation circuit 50 is explained below with reference to FIG. The compensation circuit 50 is illustrated only schematically here, it being possible to assume that the structure is comparable to the structure from FIG. 3 .

FIG. 4 shows a further converter circuit with a first area 17, a second area 20' and a coupled component 28'. The circuit area 17 represents, for example, an ACDC or DCAC converter which, starting from a three-phase AC voltage (cf. phases P1, P2 and P2), provides a direct voltage V+ and V− or vice versa, starting from the direct voltage V+ and V− provides an AC voltage on the three phases P1-P3. The second circuit area 20' is a bridge circuit which is coupled to a transformer 28' or two transformers T1 and T2. The transformers are provided with the reference symbols T1 and T2 and have, for example, a primary side P1 and a secondary side P2. The exact explanation of the circuit is shown in DE 10 2018 210579, for example. In this exemplary embodiment, the resonant circuit 50 is connected in parallel with the arrangement consisting of the elements 28' and 20'. For example, the compensation circuit 50 can be connected to the primary side on one side and to the secondary side of the transformers T1 and T2 on the other side. A connection on the primary side can take place, for example, at the two poles of C1 and C2, as illustrated here using the two connecting lines. The secondary side P2 is then connected to the other side of the compensation circuit 50. With regard to the compensation circuit 50, it should be noted once again that it can be constructed similarly to the compensation circuit 50 from FIG. This is preferably connected in series, as has already been explained above. In power electronic circuits, such as the charger shown here for an electric vehicle from DE 10 2018 210579 A, the size of the device 50 can be significantly reduced in advance with the compensation scarf by the electrical energy in the parasitic capacitances, especially in the parasitic capacitances of the transformers T1 and T2, can be recovered. The principle is as explained above.

In the above exemplary embodiments, it was assumed that the compensation path is now connected in parallel. This is explained again in other words on the basis of the following statements. For example, assuming an electric motor in an electric vehicle, the electric motor is connected to the body, e.g. B. on its housing. The compensation circuit is also connected via the common contact point 39 to the car body or car body mass or ground or the protective conductor. Furthermore, the electric motor is driven via the bridge circuit. The compensation circuit is in turn connected to the bridge circuit, e.g. B. via an intermediate circuit, so that the parallel connection of the compensation circuit results in the arrangement of the motor and bridge circuit.

Even if it was not directly shown in the above exemplary embodiments that the actuation takes place by means of a controller, the compensation device can have a controller which carries out a corresponding actuation. The main features of the control were outlined above. The control can be implemented partially in hardware and partially in software.

Although some aspects have been described in the context of a device, it should be understood that these aspects also represent a description of the corresponding method, so that a block or component of a device can also be understood as a corresponding method step or as a feature of a method step . Similarly, aspects described in connection with or as a method step also constitute a description of a corresponding block or detail or feature of a corresponding device. Some or all of the method steps may be performed by hardware apparatus (or using a Hard ware apparatus), such as a microprocessor, a programmable computer or an electronic circuit. In some embodiments, some or more of the key process steps can be performed by such an apparatus. In general, exemplary embodiments of the present invention can be implemented as a computer program product with a program code, with the program code being effective to carry out one of the methods when the computer program product runs on a computer.

The program code can also be stored on a machine-readable carrier, for example.

Other exemplary embodiments include the computer program for performing one of the methods described herein, the computer program being stored on a machine-readable medium.

In other words, an exemplary embodiment of the method according to the invention is therefore a computer program that has a program code for performing one of the methods described herein when the computer program runs on a computer.

A further exemplary embodiment of the method according to the invention is therefore a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program for carrying out one of the methods described herein is recorded. The data carrier, digital storage medium, or computer-readable medium is typically tangible and/or non-transitory.

A further exemplary embodiment of the method according to the invention is therefore a data stream or a sequence of signals which represents the computer program for carrying out one of the methods described herein. For example, the data stream or sequence of signals may be configured to be transmitted over a data communications link, such as the Internet. Another embodiment includes a processing device, such as a computer or programmable logic device, configured or adapted to perform any of the methods described herein.

Another embodiment includes a computer on which the computer program for performing one of the methods described herein is installed.

A further exemplary embodiment according to the invention comprises an apparatus or a system which is designed to transmit a computer program for carrying out at least one of the methods described herein to a recipient. The transmission can take place electronically or optically, for example. For example, the recipient may be a computer, mobile device, storage device, or similar device. The device or the system can, for example, comprise a file server for transmission of the computer program to the recipient.

In some embodiments, a programmable logic device (e.g., a field programmable gate array, an FPGA) may be used to perform some or all of the functionality of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor to perform any of the methods described herein. In general, in some embodiments, the methods are performed on the part of any hardware device. This can be universal hardware such as a computer processor (CPU) or hardware specific to the process, such as an ASIC.

The devices described herein may be implemented, for example, using hardware apparatus, or using a computer, or using a combination of hardware apparatus and a computer.

The devices described herein, or any components of the devices described herein, may be implemented at least partially in hardware and/or in software (computer program).

The methods described herein may be implemented, for example, using hardware apparatus, or using a computer, or using a combination of hardware apparatus and a computer. The methods described herein, or any components of the methods described herein, may be performed at least in part by hardware and/or by software.

The embodiments described above are merely illustrative of the principles of the present invention. It is understood that modifications and variations in the arrangements and details described herein will occur to those skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the exemplary embodiments herein.

Claims

patent claims

1. Power converter circuit (10, 10') with the following features: a bridge circuit (20, 20') with at least one half-bridge (20a, 20b, 20c), the bridge circuit (20, 20') having a further electrical component ( 28, 28') which has a parasitic capacitance (28p1, 28p2), a compensation circuit (30, 50) which is connected in parallel to an arrangement (20+28, 20'+28') of a bridge circuit (20, 20' ) and the further electrical component (28, 28'), wherein the compensation circuit (30, 50) has one or more resonance paths (31 a, 31 b, 31c) connected in parallel, each resonance path (31 a, 31 b, 31c) has at least one switchable element (32, 32a, 32b), each of the one or more parallel-connected resonance paths (31a, 31b, 31c) each having a resonance inductance (36) with an associated compensation capacitance (42, 42a, 42b, 42c) which is coupled to one or more compensation capacitances (42, 42a, 42b, 42c); wherein the resonant inductances (36) for each resonant path (31a-31c) are designed for resonant reloading.

2. Converter circuit (10, 10') according to claim 1, wherein the compensation circuit (30, 50) has three resonance paths (31a, 31b, 31c); or wherein the compensation circuit has three resonance paths (31 a, 31 b, 31c), wherein the compensation circuit (30, 50) has at least three compensation capacitances (42, 42a, 42b, 42c), each of which is connected to one of the three resonance paths (31 a , 31b, 31c) are coupled.

3. converter circuit (10, 10 ') according to any one of the preceding claims, wherein the one or more compensation capacitors (42, 42a, 42b, 42c) with a first side are coupled to the arrangement (20+28, 20'+28') and are coupled to a second side with the respective resonance path (31a, 31b, 31c).

4. Power converter circuit (10, 10 ') according to any one of the preceding claims, wherein the resonance paths (31 a, 31 b, 31 c) of the compensation circuit (30, 50) are connected to one another via a common contact point (39), the common contact point ( 39) with the arrangement (20+28, 20'+28'), the bridge circuit (20, 20'), a center tap (26a, 26b, 26c, 26) of an intermediate circuit of the bridge circuit (20, 20') or a first or a second pole of a direct voltage source is connected.

5. Power converter circuit (10, 10') according to one of the preceding claims, wherein the electrical component (28, 28') comprises an electric motor; or wherein the electrical component (28, 28') comprises an electric motor and wherein the compensation circuit (30, 50) is coupled to the protective conductor (24).

6. Power converter circuit (10, 10') according to one of claims 1 to 4, wherein the electrical component (28, 28') comprises a transformer; or wherein the electrical component (28, 28') comprises a transformer and wherein the compensation circuit (30, 50) is arranged between the primary side and the secondary side.

7. Power converter circuit (10, 10 ') according to any one of the preceding claims, which has a controller which is formed, the switchable element (32, 32a, 32b) in the one or more resonance paths (31a, 31b, 31c) respectively to be controlled in such a way that the switchable element (32, 32a, 32b) is activated before the respective associated half-bridge (20a, 20b, 20c) is switched over.

8. The power converter circuit (10, 10') according to claim 7, wherein the switchable element (32, 32a, 32b) is activated over a period of time in such a way that a resonance charge reversal takes place in equal parts before and after the switching process of the respective associated half-bridge (20a, 20b , 20c) takes place.

9. Power converter circuit (10, 10 ') according to any one of the preceding claims, wherein the switchable element (32, 32a, 32b) two series-connected switchable elements (32, 32a, 32b) per resonance path (31 a, 31 b, 31 c ) comprises or wherein the switchable element (32, 32a, 32b) comprises two series-connected switchable elements (32, 32a, 32b) for each resonance path (31a, 31b, 31c), each with opposite flow directions; and/or a switchable element (32, 32a, 32b) with two selective blocking directions.

10. Power converter circuit (10, 10') according to claim 8, wherein the switchable element (32, 32a, 32b) has two series-connected switchable elements (32, 32a, 32b) for each resonant path (31a, 31b, 31c). each has opposite flow direction and the resonance recharging is started by the respective switchable (32, 32a, 32b) element of the two series-connected switchable elements (32, 32a, 32b) of a respective resonance path (31a, 31b, 31c ) is switched on, which takes up a voltage in the current operating state, , and is switched off after the resonance recharging is complete.

11 . Power converter circuit (10, 10') according to one of the preceding claims, wherein the bridge circuit (20, 20') has one or more half-bridges (20a, 20b, 20c); and/or wherein each half-bridge (20a, 20b, 20c) has at least two further switchable elements (32, 32a, 32b).

12. Power converter circuit (10, 10') according to claim 11, wherein an intermediate tap of the half-bridges (20a, 20b, 20c) forms the first voltage tap for the electrical component (28, 28'); or wherein an intermediate tap of a first half-bridge (20a, 20b, 20c) forms the first voltage tap for the electric motor and an intermediate tap of a further half-bridge (20a, 20b, 20c) forms a second voltage tap for the electrical component (28, 28'). .

13. Power converter circuit (10, 10′) according to one of the preceding claims, wherein the compensation capacitances (42, 42a, 42b, 42c) essentially correspond to the parasitic capacitances (28p1, 28p2) in terms of their size; wherein the resonant inductance (36) depends on the parasitic capacitance (28p1, 28p2) and a switching time of the switchable element (32, 32a, 32b) in such a way that switching speeds of the switchable element (32, 32a, 32b) are, for example, between 0.3 -fold and 3-fold or 0.5-fold and 2-fold or 0.9-fold and 1.1-fold corresponds to the resonance frequency of the resonance path.

14. Power converter circuit (10, 10') according to one of the preceding claims, wherein the switchable (32, 32a, 32b) elements and further switchable elements (32, 32a, 32b) of the bridge circuit (20, 20') with regard to their switching time are comparable.

15. Method for controlling a converter circuit (10, 10') according to one of the preceding claims, wherein the switchable elements (32, 32a, 32b) in the resonance path (31a, 31b, 31c) shortly before switching over a half-bridge (20a , 20b, 20c) of the bridge circuit (20, 20') is activated.

16. The method according to claim 15, wherein the switchable element (32, 32a, 32b) is activated over a period of time so that a resonant charge reversal takes place in equal parts before and after the switching process of the respective half-bridge (20a, 20b, 20c).

17. The method according to claim 15 or 16, wherein the actuation of the switchable element (32, 32a, 32b) takes place in such a way that a resonance charge reversal is started by the respective switchable elements (32, 32a, 32b) of the two series-connected switchable Elements (32, 32a, 32b) of a resonance path (31a, 31b, 31c) is switched on, which takes on a voltage in the present operating state, and is switched off after completion of the resonance charge reversal.

18. Computer program for carrying out a method according to claim 15, 16 or 17, when the method runs on a computer.