Circuit and method for operating same

Abstract

A circuit (10) having the following features: a power converter circuit (12) comprising a DC voltage connection with two potential taps (20a, 20b) and one or more phase connections (18a, 18b, 18a', 18b', 18c'); and a controller (25), the controller (25) being designed to control switchable elements (14) of the power converter circuit (12) in such a way that a voltage at one of the two potential taps (20a, 20b) and / or at one of the one or more phase connections (18a, 18b, 18a', 18b', 18c') is modulated based on a common-mode voltage; wherein the common-mode voltage is calculated.

Description

[0001]Description Circuit and method for operating the same Embodiments of the present invention relate to an (electrical) circuit with a power converter circuit and to a corresponding operating method. According to different aspects of the invention, there are circuits designed for different applications (e.g. TN-CS system, TN-S system or TT system). Further embodiments relate to a computer-implemented method. Preferred embodiments relate to a method for reducing leakage currents for non-isolating rectifiers. When operating non-isolating rectifiers (AC-DC conversion, unidirectional or bidirectional), the common mode voltage of the rectifier creates leakage currents in the Y capacitors of the rectifier and the connected DC source or sink. Fig.Figure 1 shows a simplified common-mode equivalent circuit of a typical rectifier 100 and its EMC filter 102. High-frequency components of the common-mode voltage can be detected by the common-mode inductances L. CM of the filter 102. For low-frequency components, e.g., 50 Hz, practically unfeasible inductance values ​​for L CM necessary to ensure that the working currents occurring through C CM(galvanic coupling to the neutral conductor) below the limit value (cf. [1]). In publication [1] it is described that with the B6 topology and the EMC filter used it is not possible to reduce the leakage currents below the limit value. A later publication [2] describes that the problem of leakage currents for the three-phase topology can be reduced by a DC link symmetry controller for the capacitors. In single-phase operation, the usual H4 bridge topology results in a high low-frequency common-mode voltage and thus leakage currents, which, as described, cannot be effectively reduced with common-mode filter chokes. In the publication [3], the circuit topology shown in Fig. 2 was presented, in which the neutral conductor connection 108 (area V2-PFC) is connected to the intermediate circuit center point Final FH221002PDE-2022297546 110 (area V2-PFC).The additional intermediate circuit balancing 112 (area BC) maintains the voltages ^^^^ during operation. ^^^^1 and ^^^^ ^^^^2 symmetrical (^^^^ ^^^^1 = ^^^^ ^^^^2 ). This is necessary because the phase current i1 in single-phase operation would otherwise cause a periodic fluctuation of the voltages ^^^^ ^^^^1 and ^^^^ ^^^^2 The active filter 114 (Ripple Port RP) compensates for the 100 Hz pulsating power consumption from the mains by controlling the total power in phase opposition. This allows the total voltage to be kept constant. ^^^^1 + ^^^^ ^^^^2 be kept constant. Since the voltage at ^^^^ ^^^^2 is kept constant in theory, the low-frequency leakage current can be determined by C CMbe greatly reduced. A major challenge is the precise control of the power of the active filter 114 (range RP). This can only be achieved with limited dynamics. Furthermore, residual voltages and potential differences between the operational and system earth electrodes cannot be compensated. In the area of ​​modulation methods, there are numerous approaches in the literature for reducing leakage currents. Publication [4] describes an approach that is intended to reduce leakage currents when driving a motor. In this approach, the impedance of the filter elements is taken into account, as in the solution described in Chapter 3. However, a fourth leg / half-bridge is necessary for the control. A fluctuating intermediate circuit voltage is not taken into account. Therefore, there is a need for an improved approach.The object of the present invention is to create a concept that minimizes common-mode voltages and currents over a broad frequency range. This object is achieved by the subject matter of the independent patent claims. Embodiments of the present invention provide a circuit with a power converter circuit and a corresponding controller. The power converter circuit has a DC voltage connection with two potential taps and one or more phase connections. The controller is designed to control switchable elements of the power converter circuit, such as transistors of an H4 or B6 bridge or, in general, transistors of the power converter circuit, namely in such a way as to modulate a voltage at FH221002PDE-2022297546 one of the two potential taps and / or at one or more phase connections based on a common-mode voltage.The common mode voltage ^^^^^^^^ ^^^^ ^^^^is influenced by the following factors, among others: - fluctuation of the total intermediate circuit voltage - voltage drop across filter and mains impedance - displacement voltage - potential difference between operational and system earth electrode - fluctuations in the intermediate circuit voltage ^^^^. ^^^^ ^^^^ , especially important in single-phase operation - asymmetrical currents in three-phase operation e.g. harmonics or unbalanced loads. Examples of the invention show four methods for determining the common mode voltage V CMfor the modulation of the converter circuit, which partially or fully takes into account the (above) influencing factors on the common mode voltage ^^^^^^^^ ^^^^ ^^^^. Based on the calculation of the common mode voltage ^^^^^^^^ ^^^^ ^^^^ using these methods, the calculated common mode voltage ^^^^^^^^ ^^^^ ^^^^ can be compensated by modulating the voltage at one of the two potential taps and / or at one or more phase connections, taking into account the calculated common mode voltage ^^^^^^^^ ^^^^ ^^^^. The methods for calculating the common mode voltage ^^^^^^^^ ^^^^ ^^^^ and thus also for compensating it can be used separately or in combination. The individual calculation methods and the preferred combination are explained below. A fluctuating total intermediate circuit voltage ^^^^ ^^^^ ^^^^leads to a fluctuating common mode voltage during operation ^^^^^^^^ ^^^^ ^^^^. This influence can be calculated according to a first method based on the formula be calculated. ^^^^ ^^^^ ^^^^ is the measured voltage between two potential taps of the DC voltage connection. The voltage is the mean value of the measured voltage or, for example, the setpoint of a regulated intermediate circuit voltage. FH221002PDE-2022297546 According to a second method, the common-mode voltage calculated based on the following formula. According to a third method, the common mode voltage ^^^^ ^ ∗ ^ ^^ ^^^^ calculated based on the following formula: According to a fourth method, the common mode voltage ^^^^ ^^^^ ^^^^ based on the formula be calculated. The methods partially enable the combination of different influencing factors, as will be explained in detail below. Preferred, exemplary combinations are methods 1+2 and 1+4, since (firstly) all significant influencing variables (including filter influences) can be compensated and (secondly) good dynamics are achieved. Embodiments of the present invention are based on the finding that, through a clever control method (for the converter circuit, such as a non-isolated rectifier or AC-DC converter), the leakage currents of a capacitor C connected on the DC voltage side CMor generally a capacitance present or formed on the DC side. By selecting half the average fluctuation as the modulation value, the common mode voltage is modulated relative to ground potential, so that this voltage ^^^^^^^^ ^^^^ ^^^^ at the capacitance C CM is kept constant and leakage currents via the capacitor C CM This advantageously allows the common mode modulation of, for example, the B6 bridge in three-phase operation or an H4 bridge in single-phase operation to significantly reduce the voltage fluctuation and thus also leakage currents through C CM be reduced as well. It should be noted that ^^^^ ^^^^ ^^^^ The FH221002PDE-2022297546 modulation voltage is shown, with which the semiconductors are controlled. ^^^^^^^^ ^^^^ ^^^^is the actual voltage across capacitor C CMThe two voltages are interdependent, but different, as shown in Figs. 9a to 9d. The following table provides an overview of the calculation methods for the common-mode voltage, which is then used for modulation according to the respective implementation examples. The table for calculating the common-mode voltage also assigns the different quantities to be compensated to the individual calculation methods. The calculation methods can also be used in combination. Combinations 1 and 4 are explained below as an example. FH221002PDE-2022297546 According to the example ^^^^ ^^^^ ^^^^ can be measured. According to further embodiments, ^^^^^^^^ ^^^^ ^^^^ (for low-frequency components: ^^^^^^^^ ^^^^ ^^^^= ^^^^^^^^ ^^^^− ^^^^ ^^^^) can be measured. Alternatively, it would also be conceivable that ^^^^^^^^ ^^^^ ^^^^based on the measured voltage of ^^^^ ^^^^ ^^^^ and ^^^^ ^^^^2is determined. For one or more of the methods discussed, it is conceivable that phase current measurement ^^^^ ( ^^^^ ) of the mains current or the inductances L D1as input. For the measurements, the circuit, according to embodiments, has a measuring unit that is designed to determine or measure the corresponding voltage (see table or phase) and transfer it to the calculation unit as an input variable. At this point, it should be noted that the concept described above is designed for different network types, such as TN-CS or TN-S. The concept for common-mode voltage suppression can also be used in different modes. According to one embodiment, the currents in the one or more phases are symmetrical. An example of this is the three-phase operation of the converter circuit. According to further embodiments, the currents in the one or more phases can also be asymmetrical. An example of this would be the single-phase operation of the converter circuit. Depending on the current operating mode, the calculation method can be ^^^^ ^^^^ ^^^^In the symmetrical, for example three-phase, case, one of the calculations explained above for ^^^^ ^^^^ ^^^^ , e.g. used according to method 1. FH221002PDE-2022297546 For an asymmetrical case, such as unbalanced load, in addition to the fluctuation of the intermediate circuit voltage, the common mode voltage of the filter elements L D1 , L D2 and the network impedance, the following formula can be used (combination of calculation methods 1 and 4 from Table 1): � ^ ^^^ ^^�^^ ^�^^�^ ^�^^^ − ^^^^ ^^^^^^^^ ^^^^, ^^^^6 = ^^^^ 2+ ^^^^ ^^^^ ^^^^1 ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^2 ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^ ^^^^with At this point it should be noted that according to the embodiments the modulation voltage at the phase connections is derived from the mains voltage or mains voltage measurement ^^^^ ^^^^1 , ^^^^ ^^^^2 , ^^^^ ^^^^3and the common mode voltage ^^^^^^^^ ^^^^, ^^^^6is calculated as follows: ^^^^^^^^6, ^^^^1= ^^^^ ^^^^1 + ^^^^^^^^ ^^^^, ^^^^6^^^^^^^^6, ^^^^2= ^^^^ ^^^^2 + ^^^^^^^^ ^^^^, ^^^^6^^^^^^^^6, ^^^^3= ^^^^ ^^^^3 + ^^^^^^^^ ^^^^, ^^^^6or generally (for three phases) ^^^^ ^^^^6 = ^^^^ ^^^^ ^^^^ + ^^^^^^^^ ^^^^, ^^^^6or generalFH221002PDE-2022297546 ^^^^ ^^^^ = ^^^^ ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^This relationship between the modulation voltage and the common-mode voltage is to be applied in such a way that the individual calculation methods, e.g., 1 + 4 or 1 + 2 / 3, can be calculated using these formulas. The exact application is explained in the figure description. This applies to both the symmetrical and the asymmetrical case. According to another variant, the converter circuit is designed for single-phase operation or only for single-phase operation. In this case, the common-mode voltage can be calculated as follows (combination of calculation methods 1 and 4 from Table 1): � ^^^^ ^^^^ ^^^^, ^^^^4 =^^�^^ ^�^^�^ ^�^^^ − ^^^^ ^^^^ ^^^^2+ ^^^^ ^^^^ ^^^^1 ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^2 ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^ ^^^^with At this point it should be noted that the modulation voltage ^^^^^^^^4, ^^^^1and ^^^^^^^^4, ^^^^from the mains voltage or mains voltage measurement ^^^^ ^^^^1and the common mode voltage ^^^^^^^^ ^^^^, ^^^^4by the formulas: ^^^^^^^^4, ^^^^1= ^^^^ ^^^^1+ ^^^^^^^^ ^^^^, ^^^^4^^^^^^^^4, ^^^^= ^^^^^^^^ ^^^^, ^^^^4FH221002PDE-2022297546 is defined for the single-phase case. With regard to the above formulas, it should be noted that L defines the inductance, R the resistance, i the associated current and v the associated voltage. The index marks the position in the circuit, where 1 represents the inductances or resistances between the center tap of the converter circuit and an optional filter, 2 the inductances or resistances between the optional filter and the phase connection, and G the inductances or resistances on the mains side. With reference to the indices, it should be noted that the indices for 1 and 2 together create an LCL filter / sine filter. The concept can also be applied to other filter structures. According to embodiments, a capacitance (one capacitance per phase connection) orIn general, a capacitance arrangement can be provided at the phase connections. According to further exemplary embodiments, an intermediate circuit or a split intermediate circuit can be provided on the DC voltage side. The intermediate circuit or the split intermediate circuit is arranged, for example, between two potential taps of the DC voltage connection. According to exemplary embodiments, a center point of the intermediate circuit or of the symmetrical intermediate circuit can be connected to one phase via a capacitance or to several phases via a capacitance arrangement. As already mentioned at the beginning, the circuit can be used as part of a rectifier or a non-isolated rectifier or a battery charger. According to one exemplary embodiment, the rectifier, such as a non-isolated rectifier or a rectifier of a battery charger, is connected for operation on a TN-C, TN-CS or TN-S network.A further embodiment provides a corresponding method comprising the step of modulating a voltage at one of the two potential taps and / or at one of the phase terminals based on a common mode voltage, wherein the common mode voltage V. CM based on the formula ^ ^^^ = � ^^�^^ ^�^^�^ ^�^^^ − ^^^^ ^^^^ ^^^^^^^^ ^^^^ 2FH221002PDE-2022297546 is calculated or where the common mode voltage ^^^^ ^^^^ ^^^^ is calculated based on a formula that contains the term^�^�^^� ^^�^^� ^^�^^− ^^^^ ^^^^ ^^^^2, where ^^^^ ^^^^ ^^^^ represents the voltage between two potential taps (20a, 20b) of the DC voltage connection; and / or wherein the common mode voltage based on the formula is calculated, where ^^^^ ^^^^ ^^^^ represents the voltage between two potential taps (20a, 20b) of the DC voltage connection; and / or wherein the common mode voltage based on the formula is calculated, where ^^^^ ^^^^ ^^^^ represents the voltage between two potential taps (20a, 20b) of the DC voltage connection; and / or wherein the common mode voltage ^^^^ ^^^^ ^^^^ based on the formula is calculated. According to embodiments, the method can be computer-implemented. All embodiments explained above are optimized for common-mode compensation in TN-C, TN-S, or TN-CS systems. Common-mode voltage suppression in TT systems can be implemented according to further ^^�^^^^^∗ = ^^^^ ^ −^ ^^^^ ^^^^embodiments by the variant with the formula^^^^ ^^^^ ^^^ ^^^^− ^^^^ ^^^^ 2, since this is suitable for all network types. The circuit comprises a converter circuit which has a first voltage connection with two potential taps and one or more phase connections. The controller is designed to control the FH221002PDE-2022297546 switchable elements of the converter circuit such that a voltage at one of the two potential taps and / or at one of the phase connections is modulated based on a common mode voltage. Furthermore, the circuit comprises a measuring unit which is designed to determine a voltage between one of the potential taps and the local earth potential PE (e.g. protective conductor connection of the device). This measurement can detect an occurring displacement voltage or potential difference between the network and system earth electrode.The common-mode voltage is determined using the voltage measured by the measuring unit. A further embodiment provides a rectifier, non-isolated rectifier, or a battery charger with an explained circuit. The rectifier is preferably designed for operation on a TT system, but can, according to further embodiments, also be operated on another network system, such as a TN-C or TN-CS or TN-S system. A further embodiment provides a method for operating a corresponding circuit with the step of modulating a voltage at one of the two potential taps and / or at one of the phase terminals based on a common-mode voltage, wherein the common-mode voltage is determined using a voltage measured by a measuring unit.In this respect, the method can also comprise the step of measuring a voltage between one of the two potential taps and a protective conductor / PE (with the special feature that this protective conductor is connected to the system earth electrode instead of to the earthing of the network / transformer in the TT system). According to further embodiments, the method can be computer-implemented. In this respect, a computer program is created for carrying out the method. According to a further aspect, a voltage measurement can also be carried out in order to determine the common mode voltage. Preferably, at least one voltage on the DC voltage side is determined with respect to PE. An example of this would be the voltage from a midpoint of an intermediate circuit arranged between the potential taps with respect to PE. This can be determined, for example, by measuring the midpoint of the intermediate circuit with respect to one of the potential taps.In this case, an additional voltage measurement between a phase on the AC voltage side and the center point can also be taken into account. FH221002PDE-2022297546 In this respect, further embodiments provide a circuit with a power converter circuit having a DC voltage connection with two potential taps and one or more phase connections; and a controller, wherein the controller is designed to control switchable elements of the power converter circuit such that a voltage at one of the two potential taps and / or at one of the phase connections is modulated based on a common mode voltage; a measuring unit designed to determine a voltage on the DC voltage side with respect to ground; wherein the common mode voltage is determined using the voltage measured by the measuring unit.According to embodiments, the voltage between a center point of an intermediate circuit, which is arranged between the two potential taps, and one of the potential taps can be measured. Furthermore, for example, the voltage between a center point of an intermediate circuit, which is arranged between the two potential taps, and one of the potential taps can be measured, wherein an additional voltage on the AC voltage side is measured between one of the phases and the center point of the intermediate circuit, or wherein the additional voltage is measured between one of the phases and ground. A further embodiment relates to a rectifier, such as a non-isolated rectifier or specifically to a battery charger with a circuit according to one of the preceding claims with a measuring device. This rectifier can preferably be operated in a TT system.A further embodiment provides a method for operating this circuit. The method comprises the step of modulating a voltage at one of the two potential taps and / or at one of the phase connections based on a common-mode voltage, wherein the common-mode voltage is determined using the voltage measured by the measuring unit on the DC side with respect to ground. Of course, this method can also be computer-implemented. Embodiments of the present invention are explained below with reference to the accompanying drawings. They show: FH221002PDE-2022297546 Fig. 1 shows a simplified common-mode equivalent circuit including the structure of an EMC filter (according to [1]); Fig. 2 shows a simplified block diagram of a V2-PFC with additional activated DC link balancing (BC) (according to [3]); Fig.3 shows a schematic table illustrating various calculation methods for the common-mode voltage for use in exemplary embodiments; listing of measured variables, dynamics, and disadvantages. Fig. 4a / b / c shows different network types; Fig. 5a / b shows schematic representations for the single-phase and three-phase case, of the common-mode voltage compensation according to exemplary embodiments; Fig. 5c shows a schematic block diagram of an electrical circuit with common-mode voltage reduction for single-phase operation according to an extended exemplary embodiment; Fig. 6 shows a schematic block diagram of a circuit with common-mode voltage reduction for three-phase operation according to an extended exemplary embodiment; Fig. 7a / b / c shows schematic block diagrams of an electrical circuit with common-mode voltage reduction by means of voltage measurement according to a further exemplary embodiment;8a / b schematic block diagrams showing the calculation of the modulation voltage from the mains voltage and the common mode voltage; and Fig. 9a-d simulation results for exemplary embodiments. FH221002PDE-2022297546 Before exemplary embodiments of the present invention are explained below with reference to the accompanying drawings, it should be noted that equivalent elements and structures are provided with the same reference numerals so that their descriptions are applicable to one another or interchangeable. Before exemplary embodiments of the present invention are explained below, different network configurations, as shown in Fig. 4a, 4b and 4c as well as Fig. 6, will be briefly discussed to explain the problem, before a corresponding control concept is then explained in connection with Fig. 5c. Fig. 4a shows the connection of a consumer 150 to a TN-CS system.As can be seen, the TN-CS system comprises the three phases L1, L2, and L3 on the system side, as well as the neutral conductor and PE conductor. At the transition to the grid 152, PE and N are combined to form a PEN. The star point of the three phases and PEN is connected to the operational earth electrode 153. An earth electrode 154 is also provided on the system side. The TN-S system shown in Fig. 4b is extended in that the PE conductor is routed directly to the power grid 152'. The star point consisting of L1, L2, L3, N, and PE is connected to the operational earth electrode 153. No system earth electrode is provided on the load 150 side. A potential difference can occur between the earth (depending on whether this is the system earth electrode or the operational earth electrode) and one of the potential taps of a converter circuit.Assuming that some kind of capacitance / parasitic capacitance exists between the potential tap on one side and ground on the other, a current flow can result due to the potential difference, or in particular, the fluctuating potential difference. These currents are called leakage currents. The capacitor is referred to as C in the examples below. CM and can be present on both the negative DC link potential side and the positive DC link potential side. An example of this would be a non-isolated charger for electric cars, where the capacitance C CMby Y-capacitors in the battery or in the vehicle. In the TT network shown in Fig. 4c, the connection between the operational and system earth electrodes is made via the ground. Furthermore, potential differences can arise between the operational earth electrode and the system earth electrode due to the spreading resistance between the earth electrodes. In all network types, displacement voltage can also occur as a result of earth faults or unbalanced loads in the network. This leads to a fluctuating FH221002PDE-2022297546 potential difference between the DC-side potential tap and PE and thus to leakage currents. Leakage currents or unbalanced loads of other devices in the same network section can increase the potential fluctuation. A concept is explained below as to how the leakage current can be optimally reduced. Fig. 5c shows an electrical circuit 10 comprising a converter circuit 12 with, for example, two half-bridges 12a and 12b.The two half-bridges 12a and 12b are provided between the potential taps 20a and 20b. Each half-bridge comprises, for example, two switchable elements, designated by the reference numeral 14. The two switchable elements 14 are connected in series, with a respective center node 16 connected to a phase terminal 18 with the phases 18a and 18b. Beyond the converter circuit 12 with the potential taps 20a and 20b, a capacitor C is also provided as an example. CMwith the voltage ^^^^^^^^ ^^^^− ^^^^ ^^^^to illustrate the common-mode fluctuation on the common-mode side 20a + 20b, as well as an exemplary controller 25 for controlling the switchable elements. Now that the structure has been explained, the mode of operation will be explained. The converter circuit 12 can, for example, be a rectifier which, based on a voltage applied to the voltage terminal 18, here an AC voltage terminal, generates a DC voltage ^^^^ between the DC voltage terminals 20a and 20b or, generally, the potential taps 20a and 20b. ^^^^ ^^^^ For this purpose, the switchable elements 14 are controlled accordingly by the controller 25. The controlled variable is ^^^^ ^^^^ ^^^^ ie, the control 25 controls the concrete sequence and control times of the switchable elements 14 in such a way that a corresponding value ^^^^ ^^^^ ^^^^is reached. According to the examples, this value can be ^^^^ ^^^^ ^^^^ Of course, this can also be measured. This can result in the output voltage ^^^^ ^^^^ ^^^^ between 20a and 20b has a fluctuation which results in a common mode voltage component ^^^^ ^^^^ ^^^^ The intermediate circuit or, in general, the voltage potential of 20a and 20b can be shifted relative to the ground potential by a corresponding modulation of the elements 14 (change in voltage ^^^^^^^^ ^^^^− ^^^^ ^^^^). This voltage shift occurs via C CM As a result of the fluctuation, a corresponding current flow occurs through C CM (leakage current). FH221002PDE-2022297546 By clever modulation in the control process, the voltage ^^^^^^^^ ^^^^− ^^^^ ^^^^or ^^^^^^^^ ^^^^ ^^^^constant or as constant as possible in order to avoid leakage currents via the capacitor C CMTo avoid this, a control method is used, according to which the voltage ^^^^ ^^^^4 the switchable elements of the converter circuit (voltage ^^^^ ^^^^4 is to be described as a voltage averaged over a switching period, applied to the semiconductors or resulting from the modulation of the PWM (see Fig. 5a) with the common mode voltage ^^^^ ^^^^ ^^^^ is modulated. To adjust the voltage ^^^^^^^^ ^^^^ ^^^^ at capacitor C CM To keep constant, the voltage between potential taps 20a and 20b and PE is adjusted by half a fluctuation of the intermediate circuit voltage ^^^^ ^^^^ ^^^^ (deviating from the desired mean). Consequently, ^^^^ ^^^^ ^^^^ with the formula determined.The difference in the formula with e.g. � ^^ � ^^ ^ � ^^ � ^ ^ �^^^ − ^^^^ ^^^^ ^^^^ represents the difference to the mean value of the respective voltage. The intermediate circuit voltage ^^^^ ^^^^ ^^^^ is therefore predestined, since this value is usually the controlled variable. In this respect, statt der The setpoint from the control system can also be used to calculate the average value from the measured values. ^^^^ ^^^^ ^^^^ is shown as the voltage between the potential tap 20a and the potential tap 20b. Through the control method just explained, the common mode modulation of the converter circuit 12, here an H4 bridge in single-phase operation or also with other converter circuits, such as a B6 bridge in three-phase operation, can greatly reduce the fluctuation of the voltage ^^^^^^^^ ^^^^ ^^^^ and thus also the leakage currents through C CM be reduced by reducing the fluctuation in the intermediate circuit voltage ^^^^ ^^^^ ^^^^The resulting fluctuation is compensated. By taking this formula into account during modulation, ^^^^^^^^ ^^^^ ^^^^ is advantageously kept constant.It should be noted here that differences in the formulas, e.g. − ^^^^ ^^^^ ^^^^ typically represent a difference from the mean value of the respective voltage. Since this value is usually a controlled variable (e.g., the (measurable / measured) intermediate circuit voltage ^^^^ ^^^^ ^^^^), the setpoint from the control can be used instead of averaging from the measured value. In this respect, according to FH221002PDE-2022297546 embodiments ^ � ^ � ^^ ^ � ^^ � ^ ^ �^^^ represents the control value, such as the setpoint on the DC side or the mean value on the DC side. Fig. 5a shows an equivalent circuit for the single-phase case. The single-phase voltage connection is designated by the reference numeral 18. The modulated voltage of the semiconductors is separated into the push-pull component V L and sliding clock component (common mode) ^^^^ = 2 + ^^^^ ^^^^ ^^^^ Based on the interference effects explained above, a common mode voltage ^^^^^^^^ ^^^^ ^^^^ can occur between one of the DC voltage terminals, here DC, the DC voltage side and PE via the capacitance C CM which are generated by the modulated voltage source ^^^^ = + ^^^^ ^^^^ ^^^^ to the common mode voltage ^^^^^^^^ ^^^^ ^^^^on the capacitor C CM be compensated. In Fig. 5b, the same situation is shown starting from a three-phase voltage source 18'. The modulated voltage of the semiconductors is again separated into the push-pull component VL and sliding clock rate (common mode) ^^^^ =^^^^ ^^^^ ^^^^2 + ^^^^ ^^^^ ^^^^ Here, too, asymmetrical currents i or mains voltages 18' in the individual phases L1, L2 and L3 can lead to asymmetrical voltage drops V ZL on e.g. the filter components, so that on the DC side ^^^^ ^^^^ ^^^^ a common mode voltage ^^^^^^^^ ^^^^ ^^^^ drops across PE. A displacement voltage or leakage currents can lead to a voltage drop V ZPE at the impedance between local earthing and the operational earthing, which adds up to the common mode voltage ^^^^^^^^ ^^^^ ^^^^. These common mode voltages can be applied via the voltage source + ^^^^ ^^^^ ^^^^ by applying the common mode voltage ^^^^ ^^^^ ^^^^be compensated. An expanded exemplary embodiment is explained below with reference to Fig. 6. Fig. 6 shows a power converter circuit 12' with three half-bridges 12a', 12b' and 12c', each arranged between two potential taps 20a and 20b. Each of these three half-bridges 12a', 12b' and 12c' is connected to one of the phases via a respective center node 16. The phases are provided with the reference numerals 18a', 18b' and 18c'. In addition, the power converter circuit can also have an additional intermediate circuit 22, here a symmetrical intermediate circuit with two intermediate circuit capacitances 22C1 and 22C2. Via a center node between the two capacitors 22C1 and 22C2, which is provided with the reference symbol 22m, one or all of the phases 18a', 18b' and 18c' are capacitively coupled according to embodiments.For this purpose, a capacitor arrangement 24 with three capacitors is provided between phases 18a', 18b', and 18c'. Each of the phase connections has one or more inductances and resistors L. D1 , R D1 , L D2 , R D2 , L G and R G It should be noted that in the figures R D1 , R D2 is not shown, where R D1 , R D2 to the resistances or the ohmic component of the respective inductances L D1 and L D2 Regarding L G and R G It should be noted that the inductance L G or the resistance R G is not shown in the attached drawings and is only mentioned for the sake of completeness. This is the network impedance (network inductance and network resistance) on the side of the voltage source V G . The elements L D1 , L D2 , R D1and R D2 are arranged on the side of the converter circuit, ie in the charger (see reference symbol L), while the elements L G and R G (not shown) are arranged on the AC terminal N side. A separation between the charger side L and the mains side N is shown by a dashed line. The inductance L G and the resistance R G (marked G) are present on the mains side. The inductance L D1 and the resistance R D1 represent the series-connected inductances and their ohmic resistances between the capacitance arrangement 24 and the respective center point 16, while the inductance L D2 and the resistor R2 are arranged between the capacitor arrangement 24 and the mains connection. As a result, the elements L D1 , R D1 , L D2 , R D2 , L G and R Garranged in series, ie connected in series, namely for each phase connection 18a', 18b', and 18c'. It should also be noted that the inductors and resistors do not necessarily have to be explicitly provided electrical components, but can also be formed by the cable itself. Now that the structure has been explained in detail, the functionality will be discussed. By connecting the capacitors C X The high-frequency components of the common-mode interference voltage are applied to the intermediate circuit center point 22m ^^^^ ^^^^ ^^^^ already over L D1 and C X greatly reduced, but this is not absolutely necessary for the control process to function. The inductances L D1 , L D2 , L G and the resistors R D1 , R D2 , R Gwere assumed to be equal for the FH221002PDE-2022297546 representation. However, the method also works with different values ​​for these elements. The output voltage of the B6 bridge 12' can be modulated with a common mode voltage ^^^^^^^^ ^^^^, ^^^^6. The intermediate circuit or the potential taps 20a' and 20b' can thereby be shifted relative to the ground potential PE (change in voltage ^^^^^^^^ ^^^^− ^^^^ ^^^^). The aim of the control method is to keep the voltage ^^^^^^^^ ^^^^ ^^^^ constant in order to avoid leakage currents via the capacitor C CM This is achieved by ensuring that the output voltage of the three phases ^^^^ ^^^^6 (1) is modulated with the common-mode voltage ^^^^^^^^ ^^^^, ^^^^6(2). The intermediate circuit is shifted relative to ground potential by half the fluctuation of the intermediate circuit voltage (deviating from the desired mean value) and thus kept constant. ^^^^^^^^ ^^^^ ^^^^6, ^^^^1= ^^^^ ^^^^1+ ^^^^^^^^ ^^^^, ^^^^6(1) ^^^^^^^^6, ^^^^2= ^^^^ ^^^^2 + ^^^^^^^^ ^^^^, ^^^^6^^^^^^^^6, ^^^^3= ^^^^ ^^^^3 + ^^^^^^^^ ^^^^, ^^^^6 ^^^^ � ^^^^, ^^^^6 ^^�^^ ^ � ^^ � ^ ^ � ^^^ − ^^^^ ^^^^ ^^^^ (2) ^ ^^^ = 2The relationship shown in formulas (1) and (2) can, as shown in the table above, compensate for the common mode voltage resulting from the fluctuation of the intermediate circuit voltage (and a voltage drop across the filter components + line impedance, if applicable). Asymmetrical mains currents lead to voltage fluctuations across the elements L D1 , L D2 and L G also to a common mode voltage at C CM. This can be calculated using the relationship shown in formulas (3) to (7). The common mode voltages ^^^^^^^^ ^^^^1 ^^^^ ^^^^ and ^^^^^^^^ ^^^^2 ^^^^ ^^^^ across the chokes and resistors of the rectifier and ^^^^^^^^ ^^^^ ^^^^ across the impedance of the mains connection can be determined using formulas (4), (5) and (6). In this case, an LCL filter structure was assumed (L D1 -C X -L D2 ). Other components in the rectifier's current path must be considered accordingly. FH221002PDE-2022297546 ^^^^^^^^6, ^^^^1= ^^^^ ^^^^1 + ^^^^^^^^ ^^^^, ^^^^6(3) ^^^^^^^^6, ^^^^2= ^^^^ ^^^^2 + ^^^^^^^^ ^^^^, ^^^^6^^^^^^^^6, ^^^^3= ^^^^ ^^^^3 + ^^^^^^^^ ^^^^, ^^^^6 ^ ^^^ = � ^^�^^ ^�^^�^ ^�^^^ − ^^^^ ^^^^ ^^^^2+ ^^^^ + ^^^^ (7) ^^^^ ^^^^, ^^^^6 ^^^^ ^^^^1 ^^^^ ^^^^ ^^^^ ^^^^2 ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^ ^^^^In the above formulas, especially formula 6, R G and L Gstill listed for the sake of completeness. Consideration of the network impedance is not mandatory, as it is usually unknown. Therefore, the calculation can be carried out without ^^^^^^^^ ^^^^ ^^^^ in accordance with the exemplary embodiments. The above descriptions using the formulas have shown that compensation of the voltage drop across the filter components and, if necessary, also across the line impedance is possible. The discussion is prepared specifically for the three-phase case, but can be applied analogously to the single-phase case. In general, it can be stated that the above explanations in connection with the single-phase case are of course transferable to the three-phase case, or vice versa. FH221002PDE-2022297546 Regarding the formulas, it should be noted that the position of L D1 , R D1 , L D2 , R D2 , L G , R G has already been explained in detail. Regarding i LD1,L1 , iLD1,l2 , i LD1,L3 , i L1 , i L2 , i L3 Note that these represent the corresponding currents in phases 18a'(R), 18b'(R), and 18c'(R). The variables ^^^^ ^^^^ ^^^^ , ^^^^ ^^^^6 and ^^^^^^^^ ^^^^, ^^^^6 have already been introduced. The same applies to the variable ^^^^ ^^^^ ^^^^ In single-phase operation, the phase L1 is connected to the first half-bridge and the neutral conductor N is connected to the second half-bridge. The first half-bridge L1 is supplied with the mains voltage v L1 (in practice with the output voltage setpoint of the current regulator) and the common-mode voltage ^^^^^^^^ ^^^^, ^^^^4 (8). The second half-bridge N is controlled with the common-mode voltage ^^^^^^^^ ^^^^, ^^^^4 (9). ^^^^^^^^4, ^^^^1= ^^^^ ^^^^1+ ^^^^^^^^ ^^^^, ^^^^4(8) ^^^^^^^^4, ^^^^= ^^^^^^^^ ^^^^, ^^^^4(9) For single-phase operation, the common-mode voltages are calculated according to formulas (10) to (12). The common-mode modulation voltage for the H4 bridge is summarized in formula (13). � ^ ^^^ ^^�^^ ^�^^�^ ^�^^^ − ^^^^ ^^^^ ^ (13)^^^^ ^^^^, ^^^^4 = ^^^ 2+ ^^^^ ^^^^ ^^^^1 ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^2 ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^ ^^^^The capacity C CM can also be connected to the positive DC link terminal. An additional DC / DC converter (e.g., for a battery) can also be connected to the DC link. Depending on the design (DC- or DC+ continuous), the capacity FH221002PDE-2022297546 C CM The battery is switched from DC- or DC+ to ground potential. When compensating for the fluctuation in the intermediate circuit voltage, the fluctuation must then be negatively signed (formulas (14) and (15)). The voltage drop across the semiconductors and the voltage drop across the common mode chokes in the EMC filter can also be taken into account when compensating for the common mode voltage, but was not included in the representation and formulas due to its smaller influence. In the above embodiments, the half-bridges are controlled in such a way that the voltage is modulated based on the common mode voltage. In the above embodiments, it was assumed that the common mode voltage is calculated based on a formula with the term ^�^�^^� ^^�^^� ^^�^^− ^^^^ ^^^^ ^^^^2. This calculation method advantageously makes it possible to compensate for the common mode voltage resulting from the fluctuation in the intermediate circuit voltage. According to further embodiments, this compensation for the fluctuation in the common mode voltage is also possible using other calculation methods.An overview of four different calculation methods is shown in Fig. 3. Fig. 3 shows a table with the four calculation methods for the modulation voltage ^^^^. ^^^^ ^^^^ , namely: 1. ^ ^^^ � ^^�^^ ^�^^�^ ^�^^^ − ^^^^ ^^^^ ^^^^^^^^ ^^^^ =22. 3. 4. FH221002PDE-2022297546 As already mentioned above, these calculation methods can be used individually or in combination. A preferred combination is 1 and 2 or 1 and 4, although more than two methods can of course also be combined. In the present explanation of the exemplary embodiments, one combination, namely 1 + 4, is explained as an example. The advantages of the individual calculation methods are discussed below. Regarding 1., reference is essentially made to the above explanations. As already mentioned, the common mode voltage resulting from the fluctuation in the intermediate circuit voltage can be compensated in this way. Calculation methods 2 and 3 also make it possible to compensate for fluctuations in the intermediate circuit voltage, whereby both advantageously also enable compensation for the voltage drops across the filter and grid impedance.Calculation method 2 also takes into account displacement voltages and potential differences between the operational and system earthing electrodes. Calculation method 4 enables compensation for the voltage drop across the filter and the system impedance. Depending on the specific initial situation, one of the four variants can be selected based on the design examples. Differences arise, on the one hand, in the type and extent of the compensation, and, on the other hand, in the use of the measured variables. The measured variable for calculation method 1 can be the intermediate circuit voltage ^^^^. ^^^^ ^^^^ or the partial voltages ^^^^ ^^^^ ^^^^ = ^^^^ ^^^^1 + ^^^^ ^^^^2 be used. For the second calculation method, the voltage measurement ^^^^^^^^ ^^^^ ^^^^ with e.g. ^^^^^^^^ ^^^^ ^^^^= ^^^^^^^^ ^^^^− ^^^^ ^^^^or ^^^^^^^^ ^^^^ ^^^^= ^^^^^^^^ ^^^^ ^^^^− ^^^^ ^^^^2The third calculation method, for example, is based on a voltage measurement of ^^^^ ^^^^ ^^^^ and ^^^^ ^^^^2. For the fourth calculation method, a measurement of the phase currents or the currents in the respective inductances is used. It should be noted here that the permissible operating currents are determined depending on the device class. FH221002PDE-2022297546 The control method described here shows a significant reduction in leakage currents in simulations compared to conventional control. With reference to Fig. 7a-c, a further exemplary embodiment which is particularly suitable for the TT system will now be explained. Fig. 7a shows another electrical circuit, here an electrical charger connected to a TN-CS system. In Fig. 7b, the same charger is connected to a TN-S system. As can be seen here, a separate conductor is used for PE and not the common PEN conductor. In Fig. 7c, the connection of the same charger to a TT system is used.Both the system side and the grid side have their own earthing electrode, which, unlike TN-S and TN-CS systems, does not have a common potential through a separate connection. This can lead to displacement voltages or potential differences between the operational and system earthing electrodes. Before we go into the solution according to this exemplary embodiment, the charger and its components will be briefly explained. It should be noted here that not all components are mandatory; some are also optional. The charger, e.g. from Fig. 7a, 7b or 7c, comprises an EMC filter 1000 on the input side, which filters the respective power system (cf. voltage source V. G) with the actual rectifier 1100. The rectifier (here a PVC rectifier with LCL sine filter (differential mode filter) connects the AC voltage side of the mains with the DC voltage side 1200. 1200 here denotes the DC voltage intermediate circuit, which is arranged between the two potential taps 20a and 20b. The intermediate circuit 12 comprises two series-connected capacitors with a center point M, above which the filters arranged on the input side (EMC filter and LCL sine filter) are arranged. On the DC voltage side, an optional (non-isolated) DC-DC converter 1300 and an optional EMC filter 1400 can then follow. The reference numeral 1500 designates a DC source and / or DC sink, such as a battery. FH221002PDE-2022297546 According to embodiments, Y- Capacitors can be used as common mode filter capacitors (C Y1 and CY2 ). These capacitors are connected to ground potential on the DC voltage side. Y-capacitors in the HV electrical system of a vehicle can have a higher capacitance depending on the design and are optional. In this embodiment, different voltages can be measured, preferably voltages on the DC side, in order to regulate the common-mode voltage. According to a first embodiment for current measurement, ^^^^ ^^^^2 , i.e., between the center point M of the intermediate circuit 12 and one of the potential taps 20a and 20b, measured on the DC side. In many chargers, this measurement is performed anyway, so it does not require any additional effort. Alternatively or additionally, the AC side can also be measured. ^^^^ ^^^^ ^^^^ Using these two values, for example, a constant control at a constant value ^^^^ ^ ∗ ^ ^^ ^^^^ = − ^^^^^^^^2 This is an alternative for calculating the voltage drop across the inductance L D1 , whereby no time derivative of the current is necessary. This approach has a lower dynamic range, since the measured value must include a filter or a regulator (TF in Fig. 8 (b)). Residual voltages and potential differences between the operational and system earth electrodes and other filter components, e.g., L D2 cannot be compensated using this method. In this case, measurements are preferably performed only on the DC side, so that compensation is achieved by directly measuring the voltage to PE. A distinction can be made between several different designs. According to a first design, a voltage measurement of ^^^^^^^^ ^^^^ ^^^^as well as ^^^^ ^^^^2 These two voltages can also be written together as ^^^^^^^^ ^^^^− ^^^^ ^^^^= ^^^^^^^^ ^^^^ ^^^^− ^^^^ ^^^^2be determined. According to another variant, a direct voltage measurement of ^^^^^^^^ ^^^^− ^^^^ ^^^^ can also be carried out. The voltage ^^^^^^^^ ^^^^− ^^^^ ^^^^= ^^^^^^^^ ^^^^ ^^^^− ^^^^ ^^^^2represents the common mode voltage ^^^^^^^^ ^^^^ ^^^^, so that the common mode fluctuation of ^^^^^^^^ ^^^^ ^^^^can be regulated to zero and thus FH221002PDE-2022297546 the resulting leakage currents can be compensated or reduced. With the second type of measurement, instead of two individual measurements, a direct measurement of the common mode voltage ^^^^^^^^ ^^^^ ^^^^= ^^^^^^^^ ^^^^− ^^^^ ^^^^is carried out. According to an alternative variant, a measurement can also be carried out from DC+ to PE or from battery+ to PE. Based on this, a regulation of the common mode voltage or common mode voltage fluctuation is also possible. Advantageously, in all three variants explained last, all elements are compensated with the measurement on the DC voltage side, in particular the filter components, the intermediate circuit voltage, the network impedance, the displacement voltage, as well as potential differences between the operational and system earth electrodes.In summary, there are various ways to measure the voltage to PE (e.g., from DC+, M, DC- to PE). A combination of these methods is also conceivable, or even a combination with measuring the intermediate circuit voltage. ^^^^1 and ^^^^ ^^^^2. Generally speaking, according to embodiments, a voltage measurement is carried out on the DC side between the DC side and PE in order to derive a value that allows a conclusion to be drawn about the common mode voltage. Based on the measured value, the common mode voltage or the fluctuation in the common mode voltage is then calculated so that it can then be compensated for by adjusting the control of the converter circuit. With regard to the adjustment, it should be noted that both here and in all other embodiments, the adjustment is carried out in such a way that the calculated common mode voltage or common mode voltage fluctuation calculated on the basis of measured values ​​can be compensated for by, for example, adjusting the corresponding target value on the DC side accordingly (reducing or increasing by the fluctuation). Reference is made below to Fig.Figures 8a and 8b explain the calculation method using an exemplary block diagram. This section explicitly addresses the pulse width modulation used to regulate the common-mode voltage. Fig.8a shows a controlled system with the three elements 16, 17 and 18. Element 1600 represents the control voltage for the rectifier (e.g. generated by the current regulator) and corresponds, for example, to the principle of DE 102017216468 A1 (modulation N with 0V FH221002PDE-2022297546 and L with the phase voltage) or the control known from US 11,228,238 B2 (cf. US 11,228,238 B2, Fig. 2, modulation 120+130 by 110+140+150 so that the curves as in DE 102017216468 A1 are formed again -> i.e. N=0V L=full phase voltage). Here, in single-phase operation, the half-bridges set the neutral conductor voltage to 0 V or a duty cycle of 0.5, and the half-bridges set the full voltage for the phase conductor. In three-phase operation, all half-bridges set the full voltage.Based on the two control voltages, the pulse width modulator 1700 can then generate the modulation depth and subsequently perform the pulse width modulation. It should be noted that this can be implemented differently depending on the circuit topology. Block 1800 illustrates the application of the common-mode voltage for the control process. The voltage ^^^^. ^^^^ ^^^^ is added to all voltages (neutral and phase). The common-mode voltage ^^^^ ^^^^ ^^^^ compensated value is then taken into account the intermediate circuit voltage ^^^^ ^^^^ ^^^^ converted into pulse width modulation. Fig. 8b also starts with blocks 1600 and 1700, but is expanded to include block 1900, in which the common-mode voltage is regulated according to the above embodiments. In unit 1900, ^^^^ ^ ∗ ^ ^^ ^^^^ as input signal for the transfer function TF, which is the common mode voltage ^^^^ ^^^^ ^^^^The transfer function TF can be implemented, for example, in the form of a filter or a controller. According to the exemplary embodiments, the modulation voltage at the phase terminals is derived from the mains voltage or mains voltage measurement v L1 , v L2 , v L3 and the common mode voltage ^^^^ ^^^^ ^^^^ calculated as follows ^^^^^^^^6, ^^^^1= ^^^^ ^^^^1 + ^^^^^^^^ ^^^^, ^^^^6^^^^^^^^6, ^^^^2= ^^^^ ^^^^2 + ^^^^^^^^ ^^^^, ^^^^6^^^^^^^^6, ^^^^3= ^^^^ ^^^^3 + ^^^^^^^^ ^^^^, ^^^^6This relationship, which is shown in Figure 8a, allows, for example, the combination of methods 1 and 4. The following mathematical relationship shows the calculation of the modulation voltage in general. ^^^^ ^^^^ ^^^^ ^^^^ ^^^^. ^^^^ ^^^^6 = ^^^^ ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^FH221002PDE-2022297546 This general relationship is applicable, for example, to methods 1+2 or 1+3 (see overview Fig. 8a and 8b). In detail: As shown by block 1800, both method 1 and method 4, as well as the combination of methods 1 and 4, can be considered via this path as a simple sum of the formulas associated with methods 1 and 4. The sum of the common-mode voltage according to methods 1 and 4 is then applied to the voltage via the summation point of block 16. ^^^^ ^^^^added together. This is possible in an analogous manner in Fig. 8b, which is also made clear here by the arrow 1800, which leads to the summation point of block 1600. In addition, Fig. 8b allows the calculations according to method 1 and / or 2 to be taken into account. For this purpose, the transfer function TF in block 1900 is used. In summary, it can be stated that the common mode voltage according to method 1 and / or 4 can be calculated by adding the common mode voltage to ^^^^ ^^^^ ^^^^ can be taken into account, while alternatively or additionally the common mode voltage according to methods 2 and 3, taking into account a transfer function TF, is also added to the signal ^^^^ ^^^^ ^^^^can be added. Regarding the previous embodiments, the objective and, in particular, the efficiency will be discussed below. In these embodiments, the objective is again to provide the voltage ^^^^^^^^ ^^^^ ^^^^ with as little fluctuation as possible. This means that a reduction in the operating current by ^^^^ ^^^^ ^^^^ is desired. Figures 9a to 9d show t = 0 to 0.1 without the control method and t = 0.1 to 0.2 with the control method activated. Fig. 9a illustrates the behavior when compensating for the influence of the DC link voltage fluctuation ^^^^ ^^^^ ^^^^ . For this purpose, the voltage of the upper intermediate circuit half ^^^^ ^^^^1 kept constant and a fluctuation for the lower intermediate circuit half ^^^^ ^^^^2 assumed. The fluctuation of the voltage ^^^^ ^^^^2 leads to a fluctuation in voltage ^^^^^^^^ ^^^^ ^^^^over capacity ^^^^ ^^^^ ^^^^and thus to the leakage current ^^^^^^^^ ^^^^ ^^^^. By applying the voltage ^^^^ ^^^^ ^^^^ According to method 1, the fluctuation of ^^^^^^^^ ^^^^ ^^^^ and thus the leakage current ^^^^^^^^ ^^^^ ^^^^ can be compensated. FH221002PDE-2022297546 Fig. 9b illustrates the control based on a ^^^^^^^^ ^^^^− ^^^^ ^^^^= ^^^^^^^^ ^^^^ ^^^^ measurement. A voltage drop across the filter components ^^^^ was detected. ^^^^ ^^^^ (see Fig. 5a), a displacement voltage or voltage difference between the operational and system earth electrodes ^^^^^^^^ ^^^^ ^^^^and a fluctuation in the intermediate circuit voltage ^^^^ ^^^^ ^^^^ assumed. The superposition of these components leads to the shown common mode voltage ^^^^^^^^ ^^^^ ^^^^ over capacitance ^^^^ ^^^^ ^^^^and thus to the leakage current ^^^^^^^^ ^^^^ ^^^^. Compensation according to Method 2 can significantly reduce the leakage current. The level of the remaining leakage current depends on the filtering or the regulator used (TF Fig. 8 b). Fig. 9c illustrates compensation via voltage measurement ^^^^ ^^^^ ^^^^ in the neutral conductor path and ^^^^ ^^^^2 according to method 3 using a regulator. Here, in particular, the voltage drop across L D1 in the neutral conductor ^^^^ ^^^^ ^^^^ (see Fig. 5 a) and compensates for a fluctuation in the intermediate circuit voltage. Compensation according to Method 3 can significantly reduce the leakage current. The level of the remaining leakage current depends on the filtering or the regulator used (TF Fig. 8 b). Fig. 9d shows compensation for the voltage drop ^^^^ ^^^^ ^^^^ above the filter components (e.g. L D1Compensation according to method 4 can significantly reduce the leakage current. The amount of the remaining leakage current depends on the filtering or the regulator used (TF Fig. 8 b). All elements in the path can be taken into account by calculating the sum of the voltage drops. For example, the inductances L D1 and L D2 their resistive components, the voltage drop of the semiconductor switches, and the network impedance (this value is usually unknown) and connecting cables. For single-phase operation, for example, LD1, LD2, and the network impedance in the neutral conductor are taken into account by the last three terms in Formula 13. For multi-phase applications, the elements of the three phases are taken into account by the last three terms in Formula 7. In general, the voltage across the elements can be expressed using the following formula: ^^^^ ^^^^ = ^^^^ ^^^^ ∙ ^^^^( ^^^^) + ^^^^ ⋅^^^^ ^^^^( ^^^^)^ ^^^ ^^^^FH221002PDE-2022297546 It should be noted that the necessary derivation of the current over time is generally difficult to implement in practice. With regard to the above embodiments, it should be noted that instead of the battery, another DC voltage source or DC voltage sink can of course also be present, e.g. a fuel cell or an electrolysis system. In the embodiments explained above, the focus was on specific systems, such as the TN-CS system in this case. In other systems, such as the TN-S system or the TT system, the influences on the common mode voltage are different. For example, displacement voltages and potential differences occur between the operational and system earth electrodes, e.g. in the TT system (cf. Fig. 7c). These displacement voltage potential differences are advantageously regulated as best as possible using the approaches described above and in particular using the approach from Fig. 3, e.g. method 2.Although some aspects have been described in connection with 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. Analogously, aspects described in connection with or as a method step also represent a description of a corresponding block, detail, or feature of a corresponding device. Some or all of the method steps may be implemented by (or using) a hardware apparatus, such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, some or more of the key method steps may be performed by such an apparatus.Depending on specific implementation requirements, embodiments of the invention may be implemented in hardware or software. The implementation may be performed using a digital storage medium, such as a floppy disk, a DVD, a Blu-ray Disc, a CD, a ROM, a PROM, an EPROM, an EEPROM, or a FLASH memory, a hard disk, or other magnetic or optical storage device storing electronically readable control signals that can interact or interact with a programmable computer system such that the respective method is performed. Therefore, the digital storage medium may be computer-readable.Some embodiments according to the invention thus comprise a data carrier having electronically readable control signals capable of interacting with a programmable computer system such that one of the methods described herein is carried out. In general, embodiments of the present invention can be implemented as a computer program product with a program code, wherein the program code is effective to carry out one of the methods when the computer program product runs on a computer. The program code can also be stored, for example, on a machine-readable medium. Other embodiments comprise the computer program for carrying out one of the methods described herein, wherein the computer program is stored on a machine-readable medium.In other words, one embodiment of the method according to the invention is thus a computer program that has program code for carrying out one of the methods described herein when the computer program runs on a computer. Another embodiment of the method according to the invention is thus 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. Another embodiment of the method according to the invention is thus a data stream or a sequence of signals that represents the computer program for carrying out one of the methods described herein. The data stream or the sequence of signals can, for example, be configured to be transferred via a data communication connection, for example via the Internet.FH221002PDE-2022297546 A further embodiment comprises a processing device, for example a computer or a programmable logic device, which is configured or adapted to carry out one of the methods described herein. A further embodiment comprises a computer on which the computer program for carrying out one of the methods described herein is installed. A further embodiment according to the invention comprises an apparatus or a system designed to transmit a computer program for carrying out at least one of the methods described herein to a receiver. The transmission can be electronic or optical, for example. The receiver can be a computer, a mobile device, a storage device, or a similar device, for example.The device or system may, for example, include a file server for transferring 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 functionalities of the methods described herein. In some embodiments, a field-programmable gate array may interact with a microprocessor to perform any of the methods described herein. Generally, in some embodiments, the methods are performed by any hardware device. This may be general-purpose hardware such as a computer processor (CPU) or method-specific hardware such as an ASIC. The above-described embodiments merely illustrate the principles of the present invention.It is to be understood that modifications and variations of the arrangements and details described herein will be apparent to others 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 embodiments herein. FH221002PDE-2022297546 References [1] Common Mode Analysis of Non-Isolated Three-Phase EV-Charger for Bi-Directional Vehicle-to-Grid Operation, B. Strothmann, PCIM Europe 2019, 7 – 9 May 2019, Nuremberg, Germany [2] Common-Mode-Free Bidirectional Three-Phase PFC-Rectifier for Non-Isolated EV Charger, B. Strothmann, 2021 IEEE Applied Power Electronics Conference and Exposition [3] Single-Phase Operation of Common-Mode-Free Bidirectional Three-Phase PFC-Rectifier for Non-Isolated EV Charger with Minimized DC-Link, B.Strothmann, PCIM Europe digital days 2021, 3 – 7 May 2021 [4] Elimination of Common-Mode Voltage in Three-Phase Sinusoidal Power Converters, Alexander L. Julian, IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL.14, NO.5, SEPTEMBER 1999 Reference symbol Circuit (10) Converter circuit (12) Potential tap (20a, 20b) Phase connections (18a, 18b, 18a', 18b', 18c') Control (25) Elements (14) DC link (22) Capacitance arrangement (24) FH221002PDE-2022297546.

Claims

1. Circuit (10), with the following features: a converter circuit (12) having a DC voltage connection with two potential taps (20a, 20b) and one or more phase connections (18a, 18b, 18a', 18b', 18c'); and a controller (25), wherein the controller (25) is designed to control switchable elements (14) of the converter circuit (12) such that a voltage at one of the two potential taps (20a, 20b) and / or at one of the one or more phase connections (18a, 18b, 18a', 18b', 18c') is modulated based on a common mode voltage; wherein the common mode voltage ^^^^ ^^^^ ^^^^ based on the formula is calculated or where the common mode voltage ^^^^ ^^^^ ^^^^ is calculated based on a formula containing the term^�^�^^� ^^�^^� ^^�^^− ^^^^ ^^^^ ^^^^2, where ^^^^ ^^^^ ^^^^represents the voltage between two potential taps (20a, 20b) of the DC voltage connection; and / or wherein the common mode voltage based on the formula is calculated, where ^^^^ ^^^^ ^^^^ represents the voltage between two potential taps (20a, 20b) of the DC voltage connection; and / or wherein the common mode voltage based on the formula FH221002PDE-2022297546 is calculated, where ^^^^ ^^^^ ^^^^ represents the voltage between two potential taps (20a, 20b) of the DC voltage connection; and / or wherein the common mode voltage ^^^^ ^^^^ ^^^^ based on the formula ^^^^ = ^^^^ ⋅ ^^^^( ^ )^^^^ ^^^^( ^^^^)^^^^ ^^^^ ^^^ + ^^^^ ⋅ ^^^^ ^^^^is calculated.

2. Circuit (10) according to claim 1, wherein currents in the one or more phases (18a', 18b', 18c') are symmetrical and / or wherein the power converter circuit (12) is designed for three-phase operation.

3. Circuit (10) according to claim 1, wherein currents in the one or more phase connections (18a, 18b) are asymmetrical and / or wherein the power converter circuit (12) is designed for single-phase operation.

4. Circuit (10) according to claim 2 or 3, wherein the common mode voltage ^^^^^^^^ ^^^^, ^^^^6 based on the formula � ^ ^^^ ^^�^^ ^�^^�^ ^�^^^ − ^^^^ ^^^^ ^^^^^^^ ^^^^, ^^^^6 = ^ 2+ ^^^^ ^^^^ ^^^^1 ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^2 ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^ ^^^^with FH221002PDE-2022297546 5. Circuit (10) according to one of the preceding claims, wherein the common mode voltage is calculated based on the combination of the formulas ^^^^ ^^^^ ^ ^^^ ^^^^=^^^^ ^^^^− ^^^^ ^^^^ ^^^^2 and is calculated, where ^^^^ ^ ∗ ^ ^^ ^^^^ using a transfer function with ^^^^ ^^^^ ^^^^ can be combined to obtain the common-mode voltage.

6. Circuit (10) according to claim 2, 3, 4 or 5, wherein the relationship between a voltage at the phase terminals (18a, 18b, 18a', 18b', 18c') and a common-mode voltage is given by the formula ^^^^ ^^^^ = ^^^^ ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^ for the symmetrical or asymmetrical case.

7. Circuit (10) according to claim 2 or 3, wherein the common mode voltage is determined by the formula � ^^^^ ^^^^ ^^^^, ^^^^4 =^^�^^ ^�^^�^ ^�^^^ − ^^^^ ^^^^ ^^^^2+ ^^^^ ^^^^ ^^^^1 ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^2 ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^ ^^^^with FH221002PDE-2022297546 8. The circuit (10) according to claim 3 or 7, wherein a relationship between a voltage at one of the phase inputs and the common mode voltage is calculated by the formula ^^^^^^^^4, ^^^^1= ^^^^ ^^^^1 + ^^^^^^^^ ^^^^, ^^^^4^^^^^^^^4, ^^^^= ^^^^^^^^ ^^^^, ^^^^4 is defined for the single-phase case.

9. Circuit (10) according to one of the preceding claims, wherein it has an intermediate circuit (22) and / or a symmetrical intermediate circuit (22), wherein the intermediate circuit (22) or the symmetrical intermediate circuit (22) is arranged between the two potential taps (20a, 20b) of the DC voltage connection.

10. Circuit (10) according to claim 9, wherein a center point of the intermediate circuit (22) is connected to one phase via a capacitor or to several phases via a capacitor arrangement (24).

11. Power converter circuit (12) according to one of the preceding claims, wherein in single-phase operation ^^^^ ^^^^ ^^^^= ^^^^^^^^ ^^^^ ^^^^is defined and in three-phase operation ^^^^ ^^^^ ^^^^ = ^^^^^^^^ ^^^^ ^^^^1+ ^^^^^^^^ ^^^^ ^^^^2+ ^^^^^^^^ ^^^^ ^^^^3is defined; and / or where in single-phase operation ^^^^ = ^^^^ ^^^^ and in three-phase operation ^^^^ = ^^^^ ^^^^1 + ^^^^ ^^^^2 + ^^^^ ^^^^3 is defined. FH221002PDE-2022297546 12. Power converter circuit (12) according to one of the preceding claims, wherein the power converter circuit (12) comprises a rectifier, inverter, or AC-DC converter.

13. Circuit (10) according to one of the preceding claims, comprising a measuring unit configured to ^^^^ ^^^^ ^^^^ = ^^^^ ^^^^1 + ^^^^ ^^^^2 to be determined as input variable for the calculation and / or by ^^^^^^^^ ^^^^ ^^^^with ^^^^^^^^ ^^^^ ^^^^= ^^^^^^^^ ^^^^− ^^^^ ^^^^= ^^^^^^^^ ^^^^ ^^^^− ^^^^ ^^^^2 as input value for the calculation and / or to ^^^^ ^^^^ ^^^^ and ^^^^^^^^2 to be determined as an input variable for the calculation 14. Rectifier or non-isolated rectifier or battery charger with a circuit (10) according to one of the preceding claims.

15. Rectifier or non-isolated rectifier or battery charger according to claim 14 for operation on a TN-C, TN-Cs or TN-S system.

16. Method for operating a circuit (10) according to one of the preceding claims, wherein the method comprises a step of modulating a voltage at one of the two potential taps (20a, 20b) and / or at one of the phase terminals (18a, 18b, 18a', 18b', 18c') based on a common mode voltage, wherein the common mode voltage ^^^^^^^^ ^^^^, ^^^^6 based on the formula is calculated or where the common mode voltage ^^^^ ^^^^ ^^^^ is calculated based on a formula containing the term^�^�^^� ^^�^^� ^^�^^− ^^^^ ^^^^ ^^^^2, where ^^^^ ^^^^ ^^^^represents the voltage between two potential taps (20a, 20b) of the DC voltage connection; and / or wherein the common mode voltage ^^^^ ^ ∗ ^ ^^ ^^^^ based on the formula FH221002PDE-2022297546 is calculated, where ^^^^ ^^^^ ^^^^ represents the voltage between two potential taps (20a, 20b) of the DC voltage connection; and / or wherein the common mode voltage ^^^^ ^ ∗ ^ ^^ ^^^^ based on the formula is calculated, where ^^^^ ^^^^ ^^^^ represents the voltage between two potential taps (20a, 20b) of the DC voltage connection; and / or wherein the common mode voltage ^^^^ ^^^^ ^^^^ based on the formula is calculated.

17. Computer program for carrying out a method according to claim 16, when the method runs on a power converter circuit (12) according to one of claims 1 to 13.

18. Circuit (10), having the following features: a power converter circuit (12) which has a DC voltage connection with two potential taps (20a, 20b) and one or more phase connections (18a, 18b, 18a', 18b', 18c'); and a controller (25), wherein the controller (25) is designed to control switchable elements (14) of the power converter circuit (12) such that a voltage at one of the two potential taps (20a, 20b) and / or at one of the phase connections (18a, 18b, 18a', 18b', 18c') is modulated based on a common mode voltage; FH221002PDE-2022297546 Measuring unit configured to determine a voltage on the DC side with respect to ground; wherein the common-mode voltage is determined using the voltage measured by the measuring unit.

19. Circuit according to claim 18, wherein the voltage between a midpoint of an intermediate circuit arranged between the two potential taps (20a and 20b) and one of the potential taps is measured; or wherein the voltage between a midpoint of an intermediate circuit arranged between the two potential taps and one of the potential taps is measured, wherein an additional voltage on the AC side is measured between one of the phases and the midpoint of the intermediate circuit, or wherein the additional voltage is measured between one of the phases and ground. 20.A circuit according to claim 19, wherein the voltage between one of the potential taps and ground is measured, or wherein the voltage between the negative or the positive potential tap and ground is measured.

21. A rectifier or non-isolated rectifier or battery charger comprising a circuit (10) according to claim 18, 19 or 20.

22. A rectifier or non-isolated rectifier or battery charger according to claim 23 for operation on a TT system.

23. A method for operating a circuit (10) according to claim 20, 21 or 22, wherein the method comprises a step of modulating a voltage at one of the two potential taps (20a, 20b) and / or at one of the phase terminals (18a, 18b, 18a', 18b', 18c') based on a common mode voltage, wherein the common mode voltage is determined using the voltage on the DC side with respect to ground measured by the measuring unit. 24.Computer program for performing a method according to claim 23, when the method runs on a circuit (10) according to claim 18. FH221002PDE-2022297546.

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