Reduction circuit, system, method and computer program for reducing leakage and / or touch currents

Abstract

Exemplary embodiments include a reduction circuit for a transformerless rectifier, for reducing leakage and / or touch currents.The reduction circuit is designed to provide a control signal for the rectifier and to generate the control signal based on at least one of the following measurement information: a mains-side measurement of a displacement voltage, a mains-side measurement of a zero-sequence voltage, a DC-side voltage between a positive terminal of the rectifier and the center point of the rectifier's intermediate circuit, a DC-side voltage between the center point of the rectifier's intermediate circuit and a negative terminal of the rectifier, a common-mode component of a rectifier's dead-time voltage, a fault current, and / or a modulation-induced voltage of the rectifier. Examples of implementation also include corresponding systems, methods and computer programs for reducing leakage and / or touch currents.

Description

Technical field

[0001] Examples of implementation include reduction circuits, systems, methods and computer programs for reducing leakage and / or touch currents.

[0002] Exemplary embodiments include methods and devices for reducing leakage currents and / or touch currents for transformerless rectifiers. Background of the invention

[0003] When operating transformerless rectifiers (AC-DC conversion, unidirectional or bidirectional), common-mode voltages cause leakage currents in the Y-capacitors on the DC side, such as capacitors of a connected DC source or sink (e.g., automotive high-voltage electrical system with traction battery and drive converter).

[0004] Leakage currents can endanger the safety of people, the reliability of residual current devices and equipment, so a reduction or compensation of these currents is desirable. State of the art

[0005] Solutions using active leakage current compensation can be found in the literature. These solutions, such as those described in patent applications US 2009 / 0121805 A1 and US 10,069,480 B2, are suitable for higher frequencies above approximately 1 kHz. Active leakage current compensation is particularly difficult to implement for low frequencies, such as the mains frequency and its harmonics, because the necessary coupling networks (inductive and capacitive) become very large, or the voltage or current required for compensation is very high. The large Y-capacitors required for capacitive coupling pose a safety risk in the event of a fault, as a failure or malfunction of the compensation can generate additional, undesirable, and potentially dangerous leakage currents.

[0006] Furthermore, approaches are described in the literature that are intended to compensate for or reduce the leakage currents resulting from the fluctuation of the intermediate circuit voltage (e.g. research project HELENE [3]).

[0007] Therefore, there is a need for a concept for transformerless rectifiers that makes it possible to reduce the dangers of leakage currents and allows for an improved compromise between the applicability of the concept, e.g. for different frequency ranges, and the complexity, safety and reliability of the concept.

[0008] This is achieved through the subject matter of the independent patent claims.

[0009] Further developments in accordance with the invention are defined in the dependent claims. Summary of the invention

[0010] Exemplary embodiments include a reduction circuit for a transformerless rectifier, e.g., a PFC, e.g., a galvanically coupled rectifier, for reducing leakage and / or touch currents, e.g., for the complete or partial reduction of leakage and / or touch currents. The reduction circuit is configured to provide a control signal for the rectifier and to reduce the control signal (e.g., an additional control signal, e.g., in addition to an output signal of a current control), based on at least one of • a measurement information, e.g. V N"PE" , for example, information based on a measurement, such as a grid-side measurement of a displacement voltage, e.g., V NN" , e.g. in the form of a voltage between neutral conductor N" and protective conductor PE" (i.e. a measurement taken on the mains side, e.g. V) N"PE" , with which the displacement stress, e.g. V NN", can be calculated back or optionally the displacement stress, e.g. V NN" himself); • measurement information regarding a mains-side measurement of a zero-sequence voltage, e.g. V L"N" , e.g., a zero-sequence voltage between the phases and the neutral conductor, e.g., mains voltage harmonics, e.g., among others, mains voltage harmonics divisible by 3 (3, 6, 9, etc.), e.g., mains voltage harmonics divisible by 3 (3, 6, 9, etc.), as well as mains voltage harmonics due to cross-coupling effects (which can also cause leakage currents (although not as pronounced)) (e.g., measurement information in the form of or comprehensive line-to-neutral voltages measured on the mains side, from which the zero-sequence voltage can be calculated); • a measurement information regarding a DC-side voltage, e.g. V DC+M, between a positive terminal of the rectifier and a DC link center of the rectifier, i.e., for example, information based on a measurement from which the voltage can be deduced, or, for example, information regarding a direct measurement of the voltage (i.e., a measurement of the voltage V). DC+M ); • a measurement information regarding a DC-side voltage, e.g. V MDC- , between the intermediate circuit center of the rectifier and a negative terminal of the rectifier, i.e., for example, information based on a measurement from which the voltage can be deduced, or, for example, information regarding a direct measurement of the voltage (i.e., a measurement of the voltage V). MDC- ); and / or • information regarding a common-mode component of a rectifier's dead-time voltage, e.g. V DT;to provide (e.g. to generate, e.g. to calculate, e.g. to determine).

[0011] Additionally or alternatively, the control signal can be based, for example, on information regarding a voltage drop across a filter choke V. Ind of the rectifier, and / or e.g. based on information regarding a modulation-induced voltage V Mod The rectifier provides this information. The information for the modulation-induced voltage can, for example, also be measurement information, such as the measurement information regarding the DC voltage, e.g., V. DC+M , between the positive terminal of the rectifier and an intermediate circuit center point of the rectifier and / or the measurement information regarding the DC-side voltage, e.g. V MDC- , between the intermediate circuit center of the rectifier and the negative terminal of the rectifier. For example, the information can be the measurement information VMDC- his with the voltage V Mod The calculation is performed backwards to compensate for their influence. Furthermore, the information can also be a calculated voltage V. Mod be one that takes into account precisely that modulation-related influence on the leakage currents.

[0012] The inventors have further recognized that common-mode voltages and thus leakage currents can arise from, among other things, the following factors: • Harmonic overtones that form a zero system, for example harmonics that are divisible by 3 e.g. 3rd / 6th / 9th; • Displacement voltage, which leads to a voltage difference between the neutral conductor and the protective conductor, e.g. due to large single-phase loads or generators in the network section; • Fluctuations in the rectifier's intermediate circuit voltage (e.g., particularly pronounced in single-phase operation); • Common-mode component of the dead-time voltage of the rectifier semiconductors.

[0013] In particular, it was recognized that a measurement, e.g. of V N"PE" Taking into account the influence of the displacement voltage on the grid side enables a significant improvement in the reduction of common-mode interference voltage, for example, by means of control and / or regulation. Thus, according to the exemplary implementations, a significant improvement in the reduction of leakage currents can be achieved by adding another grid-side measurement, i.e., with minimal additional measurement effort.

[0014] It was further recognized that, by means of measurement information regarding a mains-side measurement of a zero-system voltage, e.g. V L"N" , (e.g. by means of grid-side measurements which provide information about grid voltage harmonics), it can be made possible to improve a corresponding leakage current reduction by stabilizing the DC-side common-mode voltages.

[0015] Furthermore, it was recognized that by means of information about a DC-side voltage between a positive terminal of the rectifier and an intermediate circuit center of the rectifier, e.g. V DC+M , and / or between the intermediate circuit center of the rectifier and a negative terminal of the rectifier, e.g. V MDC- , a significant improvement in the reduction of leakage currents can also be achieved with minimal additional measurement effort. The reduction circuit can therefore be designed, for example, to obtain measured values ​​for V DC+M and / or V MDC- to obtain or determine.

[0016] Thus, for example, a compensation voltage, e.g. V, can be used for control and / or disturbance feedforward based on a difference between these two voltage measurements. CY, can be determined, which can achieve a significant improvement in leakage current reduction. The compensation voltage, e.g. V CY , can for example serve as a compensation component for an alternating component of a voltage V MPE" between the intermediate circuit center of the rectifier and an earth connection, e.g. to determine the voltage V MPE" to adjust (e.g. to be so free of AC or so with reduced AC) that the leakage currents are reduced.

[0017] The compensation voltage, e.g. V CY , can be used, for example, as a compensation component for an AC component of a voltage via Y-capacitors of the rectifier in order to compensate for the AC component and reduce leakage currents.

[0018] Furthermore, the measured values ​​at the DC-side terminals of the rectifier relative to the intermediate circuit center allow for the identification of disturbance influences and thus their efficient reduction or compensation. This enables, for example, the feedforward control of disturbances, which can further improve the regulation of leakage currents.

[0019] Furthermore, it was also recognized that common-mode components of a rectifier's dead-time voltage have relevant influences on the leakage currents, and thus, based on information about these components, the reduction of disturbances can be improved.

[0020] Exemplary embodiments thus enable devices and methods for reducing leakage currents arising from the mains-side common-mode voltage (e.g. harmonics and / or displacement voltage) and for compensating for fluctuations in the DC link voltage by modulating a common-mode voltage.

[0021] Leakage currents are therefore reduced and, for example, may even be completely eliminated. To achieve this, common-mode voltage disturbances are reduced or compensated for, according to the specific implementation examples.

[0022] Leakage current compensation, unlike (e.g., unlike the compensation of the common-mode voltage according to the invention to reduce leakage currents), does not lead to a reduction of the leakage currents actually occurring in the device - these are compensated internally in order to effect a reduction at the mains connection point.

[0023] In particular, exemplary embodiments include consideration of, in addition to the total voltage, partial voltages of the intermediate circuit halves and different Y-capacitances at DC- and DC+. Furthermore, exemplary embodiments address converters with and without DC-DC converters.

[0024] Examples of implementation include, for example, optional implementations based on the respective information or measurement information, i.e. • the measurement information regarding the grid-side measurement of the displacement voltage, • the measurement information regarding the grid-side measurement of the zero-sequence voltage, • the measurement information regarding the DC-side voltage between the positive terminal of the rectifier and the intermediate circuit center (M) of the rectifier, • the measurement information regarding the DC-side voltage between the intermediate circuit center of the rectifier and the negative terminal of the rectifier, • the information regarding the common-mode component of the rectifier's dead-time voltage, and / or • the information regarding the modulation-related voltage of the rectifier • the measurement information regarding a fault current, a modeling of an influence of the associated voltage or current (or an influence derived therefrom) on the leakage currents and a determination of an associated compensation term (for the control signal), i.e. e.g. based on a theoretical influence which would be present without model-based compensation.

[0025] According to exemplary embodiments, the reduction circuit is designed to reduce the control signal by adding a disturbance component, e.g. V. CV , to provide, which is based on at least one of • the measurement information, e.g. V N"PE" , regarding the grid-side measurement of the displacement voltage, • measurement information regarding a mains-side measurement of a zero-sequence voltage, e.g. V L"N" , • the measurement information regarding the DC-side voltage, e.g. V DC+M, between the positive terminal, e.g. DC+, of the rectifier and the intermediate circuit center, e.g. M, of the rectifier, • the measurement information regarding the DC-side voltage, e.g. V MDC- , between the intermediate circuit center point, e.g. M, of the rectifier and the negative terminal, e.g. DC-, of the rectifier, • the information regarding the common-mode component of the rectifier's dead-time voltage, e.g. V DT , and / or • the information regarding the modulation-induced voltage, e.g. V Mod , rectifier-based.

[0026] It was recognized that, based on the information above, disturbance influences can be determined and thus also incorporated to enable disturbance compensation or reduction. This allows an optional, e.g., additional, control system to be relieved of some of its load if, for example, a control error can be reduced in advance by incorporating disturbances.

[0027] According to exemplary embodiments, the reduction circuit is therefore optionally designed in particular to determine the disturbance feedforward component based on a component of the common-mode voltage, which is based on a circuit topology and / or modulation of the rectifier, e.g. V Mod , and the reduction circuit is further designed to reduce the common-mode voltage component which is based on the circuit topology and / or modulation of the rectifier, based on the measurement information regarding the DC-side voltage, e.g. V MDC-, between the intermediate circuit center point, e.g. M, of the rectifier and the negative terminal, e.g. DC-, of the rectifier and based on the measurement information regarding the DC-side voltage, e.g. V DC+M , between the positive terminal of the rectifier and the intermediate circuit center of the rectifier.

[0028] It was recognized that by measuring potential differences between the DC-side potential taps of the rectifier and the intermediate circuit center, influences of the circuit topology and / or modulation of the rectifier can be calculated, whereby based on these influences or quantities, a portion of a control signal for leakage current reduction can be generated.

[0029] According to the exemplary embodiments, a corresponding voltage (i.e., a quantity for feedforward disturbances), e.g., V, can therefore be used. Mod, depending on the circuit topology. For example, the voltage V must be Mod The potential difference between M* and M can even be considered (e.g., under certain circumstances) for the various circuit topologies. The goal is, for example, to determine the voltage V. Mod to compensate for, which can represent a disturbance variable. For a two-level topology such as, for example, the following in Fig. 9 on the left is, for example, the voltage difference between the upper intermediate circuit half V DC+M and the lower half V MDC- dependent. The common-mode component of the modulation V Mod This can be calculated and compensated appropriately, or even must be calculated and compensated appropriately for the PFC circuit topology and modulation used.

[0030] According to exemplary embodiments, the reduction circuit is designed to reduce the disturbance feedforward component based on a component, e.g. V ind, to provide the common-mode voltage, which is based on the influence of a filter choke in the rectifier. It was recognized that taking the influence of the filter chokes into account allows for an improvement in the reduction of leakage currents.

[0031] According to exemplary embodiments, the reduction circuit is designed to reduce the disturbance feedforward component based on, • a sum, e.g. V L''PE" e.g. V L"N" , from measurement information regarding mains-side voltages (e.g. conductor-to-earth potential measurements, e.g. V 1"PE" , V 2"PE" , V 3"PE" e.g. V 1"N' , V 2"N" , V 3"N" ) (e.g. for operation without a neutral conductor), and / or • a measurement information regarding an AC component of a voltage from Y-capacitors arranged on a DC side of the transformerless rectifier, e.g. V C e.g. V CY e.g. V CYp and V CYn,to provide.

[0032] The measurement information regarding an AC component of a voltage from Y-capacitors arranged on a DC side of the transformerless rectifier can be obtained, for example, by means of a voltage measurement with respect to V. MDC- be determined.

[0033] In particular, the sum, e.g. V, can be used to calculate the sum, e.g. L"N" , a zero-system voltage is taken into account from measurement information, thus compensating for the influence of network harmonics.

[0034] According to exemplary embodiments, the reduction circuit is designed to reduce the feedforward component of the disturbance, or at least a portion thereof, e.g., V. CV , based on a difference between • a sum of mains voltages, e.g. V L"PE" e.g., V L"N" , with the measurement information, e.g. V N"PE" , regarding the displacement voltage measured on the grid side and • a measurement piece of information or information (e.g. V) CY ), which is derived from a measurement, with respect to an alternating component of a voltage (V MPE" ) between the intermediate circuit center (M) and an earth potential (PE) of the rectifier; or based on a difference between • a sum of mains voltages, e.g. V L"PE" e.g., V L"N" , with the measurement information, e.g. V N"PE" , regarding the displacement voltage measured on the grid side and • a measurement piece of information or information (e.g. V) CY ), which is derived from a measurement, with respect to an AC component of the Y-capacitor voltages, e.g. for operation without a neutral conductor, i.e. e.g. as a term of the form VN''PE''(t)+VL''N''(t)−VCY(t).

[0035] According to exemplary embodiments, the reduction circuit is designed to reduce the feedforward component of the disturbance, or at least a portion thereof, e.g., V. CV , based on a difference between • the network-side measurement information, e.g. V N"PE" , regarding the displacement stress and • a measurement piece of information or information (e.g. V) CY ), which is derived from a measurement regarding an AC component of the Y-capacitor voltages, or based on a difference between • the network-side measurement information, e.g. V N"PE" , regarding the displacement stress and • a measurement piece of information or information (e.g. V) CY ), which is derived from a measurement, with respect to an alternating component of a voltage (e.g. V) MPE") between the intermediate circuit center (e.g. M) and an earth potential (e.g. PE") of the rectifier, e.g. for operation with neutral conductor, e.g. as a term of the form V N"PE" (t) - V CY (t).

[0036] Further subtrahends for determining the disturbance feedforward component, e.g. V CV This can include, for example, a dead time voltage V DT (e.g. determined based on information regarding the common-mode component of the dead-time voltage (V) DT ) of the rectifier) ​​and / or a modulation-induced voltage V Mod (e.g. determined based on information regarding the modulation-induced voltage (V) Mod ) of the rectifier).

[0037] It was recognized that this would result in improved interference suppression for common-mode voltage compensation.

[0038] According to exemplary embodiments, the reduction circuit is designed to provide the control signal with a manipulated variable component, e.g., an output signal of a controller, such as a PI controller (e.g., PI(z)), e.g., in combination with the disturbance feedforward component (or where the control signal is, for example, the manipulated variable component). Furthermore, the reduction circuit is designed to reduce a setpoint, e.g., V. NM* e.g. V LM* , to obtain, for example, determine the voltage between a mains connection of the rectifier, e.g. N, e.g. L, and the intermediate circuit center, e.g. M, of the DC side of the rectifier, and to determine the manipulated variable component based on a deviation, e.g. control deviation, between • the target value, e.g. V NM* e.g. V LM* , for the voltage between the mains connection, e.g. N, e.g. L, and the intermediate circuit center and • a measurement information regarding the voltage, e.g. V L"M e.g. V N"M , to provide between the network connection, e.g. L, e.g. N, and the intermediate circuit center point.

[0039] According to exemplary embodiments, the reduction circuit is designed to reduce the setpoint, e.g. V NM* e.g. V LM* , to determine the voltage between the mains connection of the rectifier, e.g. N, e.g. L, and the intermediate circuit center, e.g. M, of the rectifier.

[0040] For example, the reduction circuit can be designed to reduce the measurement information regarding the voltage, e.g., V. L"M e.g. V N"M , between the mains connection, e.g. L, e.g. N, and the intermediate circuit center point based on measurement information regarding one or more voltages, e.g. V 1"M , V 2"M , V 3"M, between one or more mains connections of the rectifier and a DC link center point, e.g. M, of the rectifier (i.e., for example, by means of or based on measurement information regarding voltages between mains connection and the center tap M of the DC link).

[0041] According to exemplary embodiments, the reduction circuit is designed to reduce the setpoint for the voltage, e.g. V NM* e.g. V LM* , between the rectifier's mains connection, e.g. N, e.g. L, and the intermediate circuit center, e.g. M, of the rectifier based on • a sum, e.g. V L"PE" e.g., V L''N'' , from measurement information regarding mains voltages (e.g. V 1''PE'' , V 2''PE'' , V 3''PE'' e.g. V 1''N'' , V 2''N'' , V 3''N'' ) (e.g. in operation without a neutral conductor; e.g. in the form of or as the measurement information regarding the mains-side measurement of the zero-system voltage), • the measurement information, e.g. V N''PE'' , regarding the grid-side measurement of the displacement voltage • a measurement piece of information or information (e.g. V) CY ), which is derived from a measurement (e.g., from a measurement of V) DC+M and / or V MDC- ), with respect to an alternating component of a voltage (V MPE'' ) between the intermediate circuit center (M) and an earth potential (PE'') of the rectifier and / or • a measurement piece of information or information (e.g. V) CY ), which is derived from a measurement (e.g., from a measurement of V) DC+M and / or V MDC- ), with respect to an alternating component of a voltage from Y-capacitors arranged on a DC side of the transformerless rectifier, e.g. V C e.g. V CY e.g. V CYp +V CYn ,to determine.

[0042] The reduction circuit is therefore designed, for example, to calculate a value based on a difference between the sum of measurement information regarding mains-side voltages and the measurement information regarding the mains-side measurement of the displacement voltage, and the measurement information or information (e.g., V). CY ), which is derived from a measurement regarding the AC component of the voltage of Y-capacitors arranged on the DC side of the transformerless rectifier, e.g. as a term or partial term, e.g. in the form V N''PE'' (t) + V L''N'' (t) - V CY (t) to determine the setpoint, e.g. for the case of operation without a neutral conductor.

[0043] The reduction circuit is designed, for example, as an alternative or additional measure to calculate a value based on a difference between the measurement information, e.g., V. N''PE'' , regarding the grid-side measurement of the displacement voltage and the measurement information or information (e.g. V)CY ), which is derived from a measurement, regarding the AC component of the voltage of Y-capacitors arranged on the DC side of the transformerless rectifier, i.e. e.g. as a term or partial term, to determine the setpoint, e.g. for the case of operation with neutral conductor.

[0044] The information (e.g. V CY ), which is derived from the measurement, regarding the AC component of a voltage from Y-capacitors arranged on the DC side of the transformerless rectifier, can be determined by means of a measurement or measurement information regarding V MDC- (and / or V) DC+M ) will be provided. Based on V MDC- (and / or V) DC+M ) can, for example, refer to the exchange rate V CY It is calculated backwards, representing a compensation variable to suppress or reduce otherwise existing exchange components.

[0045] The reduction circuit is designed, for example, as an alternative or additional measure to calculate a value based on a difference between the measurement information, e.g., V. N''PE'' , regarding the grid-side measurement of the displacement voltage and one from measurement information (e.g. V MDC- and / or V DC+M ) calculated exchange rate (e.g. V CY ) a voltage (e.g. V) MPE'' ) to determine the setpoint between the intermediate circuit center (M) and an earth potential (PE'') of the rectifier, e.g. as a term or partial term in the form of V N''PE'' (t) - V CY (t).

[0046] The determination of the setpoint based on AC voltage-side as well as DC voltage-side measurements or measurement information, e.g. by deriving intermediate quantities such as V. CY , enables the setting of a setpoint that allows efficient suppression of common-mode voltage fluctuations in order to reduce any leakage currents.

[0047] The voltages on the DC side relative to PE, e.g., V CY , V CYp , V CYn According to some embodiments, values ​​are not necessarily measured directly, or are not measured directly, but are optionally derived from other measured values, e.g., from the other measured values, e.g., V. DC+M and / or V DC-M and calculated from the network measurements. In an alternative direct measurement (according to further embodiments), the low-pass behavior of the filter chokes and the C can, for example, Y Capacitors (LC low-pass filter) in the relevant frequency range cause a phase shift and reduction in amplitude, so that feedforward control and / or regulation may no longer be so easy, which is why indirect determination in the form of back-calculation can have corresponding advantages.

[0048] However, some implementation examples also optionally include direct measurement, for example, by limiting the bandwidth to frequencies below the resonant frequency of the LC low-pass filter or by using more complex controllers (e.g., more complex than a PI controller). This may only work well for periodic disturbances, but these approaches may encounter problems with dynamic changes.

[0049] V CY This includes, for example, the voltage resulting from the fluctuating intermediate circuit voltage (V). DC+M , V DC-M ) is necessary for calculation purposes, for example, or can be used to calculate the voltage across the Y capacitors V CYn +V CYp to keep it constant or to adjust it accordingly with / without DCDC so that the resulting leakage current becomes minimal or zero, or at least reduced.

[0050] The calculated voltage V CYThe PFC can then be "recreated" via Common Mode Modulation.

[0051] It should be noted generally for exemplary implementations that information or measurement information regarding a quantity can be either information that describes the quantity itself or information from which the quantity can be calculated. For example, depending on the application and available measuring points, a direct or indirect determination can be used.

[0052] According to exemplary embodiments, the reduction circuit is designed to adjust the setpoint for the voltage between the mains connection of the rectifier and the intermediate circuit center of the rectifier based on • a measurement information regarding one or more voltages, e.g. V 1''PE'' , V 2''PE'' , V 3''PE'', between one or more grid connections (e.g., one or more grid-side phases) of the rectifier and an earth potential, e.g., PE'', of the rectifier, i.e., for example, by means of or based on measurement information regarding voltages between the grid connection and earth potential, e.g., PE'', e.g., as a direct measurement, and / or • a measurement information regarding one or more voltages (e.g. V) 1''N'' , V 2''N'' , V 3''N'' ) between one or more network connections (e.g., one or more network-side phases) of the rectifier and a neutral conductor, e.g., as a combined measurement.

[0053] According to exemplary embodiments, the reduction circuit is designed to • to obtain measurement information or information (e.g. V) CY ), which is derived from a measurement (e.g., from a measurement of V) DC+M and / or V MDC-), regarding the AC component of the voltage, the Y-capacitors arranged on the DC side of the transformerless rectifier, and / or • to obtain measurement information or information (e.g. V) CY ), which is derived from a measurement (e.g., from a measurement of V) DC+M and / or V MDC- ), regarding the alternating component of the voltage (e.g. V MPE'' ) between the intermediate circuit center (M) and an earth potential (PE'') of the rectifier based on • the measurement information regarding the DC-side voltage, e.g. V DC+M , between the positive terminal of the rectifier and the intermediate circuit center of the rectifier, • the measurement information regarding the DC-side voltage, e.g. V MDC- , between the intermediate circuit center of the rectifier and the negative terminal of the rectifier, and / or • to determine information regarding the capacitances of the Y capacitors, e.g. to take into account the influencing factors fluctuating total DC link voltage, fluctuation of the partial voltages and / or size of the Y capacitances.

[0054] As explained above, according to exemplary implementations, e.g., using the measurement information, e.g., V DC+M e.g. V MDC- , on the AC component of the voltage of the Y-capacitors arranged on the DC side of the transformerless rectifier or on an AC component of the voltage (e.g. V MPE'' ) between the intermediate circuit center (M) and an earth potential (PE'') of the rectifier or to a compensation quantity corresponding to one or the other AC component (e.g. V) CY ) can be calculated backwards.

[0055] The measurement information is therefore not necessarily the information regarding the AC component itself, but rather, for example, a measured quantity that enables the determination of the AC component of the voltage or a component to compensate for this AC component.

[0056] Thus, in anticipation of the figures explained below, regarding the calculated alternating component of the voltage V CY pointed out that the voltage V CY in Fig. 9 e.g. as a replacement size for the right part from M in Fig. 7 / 8 can be viewed, so that Fig. 7 / 8 to Fig. 12 / 13 can be simplified.

[0057] The entire DC component with the voltage measurements V DC+M and V MDC- and thus the fluctuation of the voltage across the Y capacitors is reduced, for example, to V CY reduced. The fluctuation of the voltage across the Y capacitors can therefore be reduced, for example, by means of V CYtaken into account (e.g., compensated for).

[0058] The node M can be adjusted by means of the appropriate common mode modulation so that the voltage V is present between M and PE. CY adjusts so that the effect of the fluctuation of V DC+M and V MDC- and the resulting fluctuation of the voltage across the Y capacitors (or resulting fluctuations of the voltage V) MPE'' ) and thus the resulting leakage current is reduced or even eliminated.

[0059] According to exemplary embodiments, the reduction circuit is designed to reduce the control signal by adding a disturbance component, e.g. V. CV , to provide, which is based on at least one of • the measurement information, e.g. V N''PE'' , regarding the grid-side measurement of the displacement voltage • the measurement information regarding a grid-side measurement of the zero-sequence voltage, • the measurement information regarding the DC-side voltage, e.g. V DC+M , between the positive terminal, e.g. DC+, of the rectifier and the intermediate circuit center, e.g. M, of the rectifier, • the measurement information regarding the DC-side voltage, e.g. V MDC- , between the intermediate circuit center point, e.g. M, of the rectifier and the negative terminal, e.g. DC-, of the rectifier, and / or • the information regarding the common-mode component of the rectifier's dead-time voltage, e.g. V DT (and / or, for example, information regarding a voltage drop of a filter choke V) Ind , and / or, for example, information regarding a modulation-induced voltage V Mod)based and the reduction circuit is designed to provide the control signal with a manipulated variable component, e.g., an output signal of a controller, e.g., a PI controller (e.g., PI(z)), e.g., in combination with the disturbance feedforward component). Furthermore, the reduction circuit is designed to reduce a setpoint, e.g., V NM* e.g. V LM* , to obtain, for example, a voltage between a mains connection of the rectifier, e.g. L, e.g. N, and the intermediate circuit center, e.g. M, of the rectifier's DC side, and to determine the manipulated variable component based on a deviation, e.g. control deviation, between • the target value, e.g. V NM* e.g. V LM* , for the voltage between the mains connection and the intermediate circuit center and • a measurement information regarding the voltage, e.g. V L''M e.g. V N''M, to provide between the grid connection and the intermediate circuit center point.

[0060] According to exemplary embodiments, the reduction circuit is designed to reduce the control signal, e.g., a manipulated variable component, based on • a measurement information regarding one or more voltages (e.g. V) 1''PE'' , V 2''PE'' , V 3''PE'' ) between one or more mains connections (e.g. mains voltage-side phases, e.g. L1, L2, L3, or 1, 2, 3) of the rectifier and an earth potential, e.g. PE'', of the rectifier, e.g. as a direct measurement, and / or • a measurement information regarding one or more voltages (e.g. V) 1''N'' , V 2''N'' , V 3''N'' ) between one or more mains connections (e.g. mains voltage-side phases, e.g. L1, L2, L3, or 1, 2, 3) of the rectifier and neutral conductor, e.g. as a combined measurement, and / or • to provide measurement information regarding one or more voltages between one or more mains connections (e.g., mains voltage-side phases L1, L2, L3, or 1, 2, 3, e.g., of the neutral conductor N) of the rectifier and a DC link center point, e.g., M, of the rectifier (i.e., for example, by means of or based on measurement information regarding voltages between the mains connection and the center tap M of the DC link), e.g., in the form of a voltage V GPE'' .

[0061] According to exemplary embodiments, the reduction circuit is designed to reduce the control signal based on measurement information regarding a load voltage, e.g. V B , to provide a load located on a DC side of the transformerless rectifier.

[0062] According to exemplary embodiments, the reduction circuit is designed to reduce the control signal based on measurement information regarding a mains-side measurement of a fault current, e.g. I RCMU , to provide.

[0063] Further embodiments include a reduction circuit for a transformerless rectifier for reducing leakage and / or touch currents, wherein the reduction circuit is configured to provide a control signal for the rectifier. The reduction circuit is configured to generate the control signal based on measurement information regarding a fault current, e.g., I RCMU , to provide.

[0064] The inventors recognized that, in addition to voltage-based measurement information, current-based measurement information can also be used to provide a control signal for leakage current reduction. Measuring a fault current, for example, a differential current, based on a sum of line-side measurements of conductor currents excluding the protective earth (PE) conductor, allows for the compensation of resonance effects that cause leakage currents. In this way, based on the current measurement, a disturbance feedforward component can be applied, which reduces or prevents a portion of leakage currents resulting from the resonance behavior of DC-side capacitors with the rectifier inductors and, optionally, the inductors of a DC-DC converter.

[0065] Based on the current measurement, a virtual resistor, e.g. R, can be used for this purpose. VD, for the rectifier circuit, so that leakage current contributions of the resonant circuit can be comprehensively reduced by the Y capacitors and inductors, such as common-mode chokes and differential-mode chokes.

[0066] According to exemplary embodiments, the reduction circuit is thus designed, for example, to reduce a disturbance feedforward component, e.g. V CV , of the control signal based on the measurement information regarding the fault current, e.g. I RCMU , to provide.

[0067] According to exemplary embodiments, the measurement information regarding the fault current, e.g. I RCMU , for example, a sum of measured currents of all network-side conductors except for a protective conductor (PE).

[0068] According to exemplary embodiments, the reduction circuit is designed to comprehensively reduce the control signal based on a model of the influence of a series resonant circuit. • Y-capacitors arranged on the DC side of the transformerless rectifier and • Filter chokes of the rectifier; to a common-mode voltage of the rectifier, using the measurement information regarding the fault current, e.g. I RCMU , to provide.

[0069] According to exemplary embodiments, common-mode interference suppression chokes and / or differential-mode chokes of the rectifier are taken into account for the series resonant circuit.

[0070] According to exemplary embodiments, the reduction circuit is designed to reduce the control signal based on measurement information, e.g. V N''PE'' , regarding a grid-side measurement of a displacement voltage, e.g. V NN'' , to provide.

[0071] Further embodiments include a system with a reduction circuit according to exemplary embodiments, a transformerless rectifier, and a control device, e.g., PWM, wherein the control device is configured to control the rectifier based on an input signal and is connected to a controller, e.g., a current controller, to provide a control signal for regulating a mains current and / or the DC link voltage of the rectifier. The system is configured to provide a combination, e.g., a superposition, e.g., a sum, of the control signal and the control signal as an input signal for the control device.

[0072] According to exemplary embodiments, the system is designed to determine a setpoint for the DC link voltage of the rectifier as a function of the measurement information regarding the mains-side measurement of the displacement voltage, e.g. V N''PE'', to adjust, e.g. to increase, e.g. to allow enough reserve for the control, e.g. by means of pulse width modulation, of the common-mode voltage.

[0073] Exemplary embodiments further include a method for a transformerless rectifier, e.g., PFC, e.g., a galvanically coupled rectifier, for reducing leakage currents and / or touch currents (e.g., for the complete or partial reduction of leakage currents, e.g., for the reduction of leakage and / or touch currents, e.g., for the reduction of leakage currents acting on a transformerless rectifier), wherein the method has the following features: providing (e.g., generating, calculating, or determining) a control signal (e.g., an additional control signal, e.g., in addition to an output signal of a current control) for the rectifier based on at least one of • a measurement information, e.g. V N''PE'', for example, information based on a measurement regarding a network-side measurement of a displacement voltage (e.g., a voltage between neutral conductor N'' and protective conductor PE''); • measurement information regarding a mains-side measurement of a zero-sequence voltage, e.g. V L''N'' , e.g. a zero-sequence voltage between the phases and the neutral conductor, e.g. mains voltage harmonics; • a measurement information regarding a DC-side voltage, e.g. V DC+M , between a positive terminal of the rectifier and an intermediate circuit center of the rectifier, i.e., for example, information based on a measurement from which the voltage can be deduced, or for example, information regarding a direct measurement of the voltage; • a measurement information regarding a DC-side voltage, e.g. V MDC-, between the intermediate circuit center of the rectifier and a negative terminal of the rectifier, i.e., for example, information based on a measurement from which the voltage can be deduced, or for example, information regarding a direct measurement of the voltage; • information regarding a common-mode component of a rectifier's dead-time voltage, e.g. V DT ; and / or • information regarding a modulation-induced voltage (V) Mod ) of the rectifier.

[0074] Methods according to the invention may include details, functionalities, and features corresponding to devices according to the invention. Similarly, devices according to the invention may have corresponding details, functionalities, and features which are disclosed in the context of a method according to the invention.

[0075] Exemplary embodiments further include a computer program with program code for carrying out a method according to exemplary embodiments, e.g. according to the method explained above, if the program runs on a computer. Character description

[0076] Exemplary embodiments according to the present disclosure are explained in more detail below with reference to the accompanying figures. With regard to the schematic figures shown, it should be noted that the functional blocks depicted are to be understood both as elements or features of the device according to the disclosure and as corresponding process steps of the disclosed method, and corresponding process steps of the disclosed method can also be derived from them. The figures show: Fig. 1 a schematic view of a reduction circuit according to exemplary embodiments; Fig. Two schematic, simplified circuit diagrams for a rectifier (PFC), left, and a rectifier (PFC) with an additional DC-DC converter, right, according to exemplary embodiments; Fig. 3 a schematic view of the circuit Fig. 2, right, with a body resistance R K in the event of an interruption of the protective conductor; Fig. 4 schematic views of an equivalent circuit diagram, left, and of voltages, right, in the TN-CS three-phase four-wire system according to exemplary embodiments; Fig. 5 schematic views of network shapes, which can be addressed with examples of implementation; Fig. 6 a schematic view of a block diagram with voltage measurements for a rectifier according to exemplary embodiments; Fig. 7 a schematic view of a common-mode equivalent circuit for the phases and neutral conductors according to exemplary embodiments; Fig. 8 a schematic view of a common-mode equivalent circuit for the phases and neutral conductors with direct measurement according to exemplary embodiments; Fig. 9 schematic views of simplified equivalent circuit diagrams for a rectifier (PFC), left, and a rectifier with additional DC-DC converter, right, according to exemplary embodiments; Fig. 10 more schematic views of simplified equivalent circuits for a power factor rectifier (PFC) with DC-DC converter and variable battery voltage V B , left, and simplification for a constant battery voltage V B , right, according to examples of implementation; Fig. 11 schematic views of rectifier topologies according to exemplary implementations; Fig. 12 a schematic view of a common-mode equivalent circuit for operation without a neutral conductor according to exemplary embodiments; Fig. 13 a schematic view of a common-mode equivalent circuit for operation with neutral conductor according to exemplary embodiments; Fig. 14 a schematic view of a control structure of a leakage current reduction method according to exemplary embodiments; Fig. 15 a schematic view of a simplified common-mode mean value simulation model according to exemplary implementations; Fig. 16 schematic views of simulation results for a simplified mean value model according to exemplary implementations; and Fig. 17 a schematic view of a measurement setup for testing a reduction circuit according to exemplary embodiments; Fig. 18 a plot of measurement results for a leakage current spectrum in 3-phase operation with CY=2µF for the measurement setup from Fig. 17, according to exemplary embodiments; Fig. 19 a plot of measurement results for a leakage current spectrum in 3-phase operation with CY=4µF for the measurement setup from Fig. 17, according to exemplary embodiments; Fig. 20 a plot of measurement results for a leakage current spectrum in 1-phase operation with CY=2µF for the measurement setup from Fig. 17, according to exemplary embodiments; Fig. 21 a plot of measurement results for a leakage current spectrum in 1-phase operation with CY=4µF for the measurement setup from Fig. 17, according to exemplary embodiments; Fig. 22 a schematic view of an optional intermediate circuit voltage regulator according to exemplary embodiments; and Fig. 23 a schematic view of a block diagram with common-mode interference suppression chokes and differential-mode chokes for a rectifier with DC-DC converter according to exemplary embodiments; Fig. 24 a schematic view of a simplified equivalent circuit for the series resonant circuit comprising Y-capacitors and filter chokes of the rectifier arranged on the DC side of the transformerless rectifier, according to exemplary embodiments; Fig. Figure 25 shows the schematic equivalent circuit diagram from Fig. 24 in the context of the regulation from Fig. 14, according to exemplary embodiments; and Fig. 26 a simulation result as an example of the virtual damping of the series resonant circuit according to exemplary embodiments. Detailed description of the embodiments according to the figures

[0077] Before the following exemplary embodiments are explained in detail with reference to the drawings, it should be noted that identical, functionally equivalent or equivalent elements, objects and / or structures in the different figures are provided with the same or similar reference numerals, so that the description of these elements shown in different exemplary embodiments is interchangeable or can be applied to each other.

[0078] Fig. Figure 1 shows a schematic view of a reduction circuit according to exemplary embodiments. Fig. Figure 1 shows a reduction circuit 110 for a transformerless rectifier 130, for reducing leakage and / or touch currents. The rectifier 130 is supplied by an electrical network 120 via a supply signal 121 (e.g., network voltages).

[0079] The reduction circuit is designed to provide a control signal 111 for the rectifier 130. The control signal 115 is based on at least one of • a measurement information 112 regarding a network-side measurement of a displacement voltage, • a measurement information 113 regarding a mains-side measurement of a zero-system voltage, • a measurement information 114 regarding a DC-side voltage, between a positive terminal 131 of the rectifier and an intermediate circuit center of the rectifier, • a measurement information 115 regarding a DC-side voltage between the intermediate circuit center of the rectifier and a negative terminal 132 of the rectifier, • information 116 regarding a common-mode component of a dead-time voltage of the rectifier, and / or • information regarding a modulation-induced voltage (V) Mod) of the rectifier.

[0080] Information 116 regarding the common-mode component of the rectifier's dead-time voltage (e.g., in the form of the dead-time voltage itself) can be calculated, for example, using methods known from the literature. Information 116, e.g., the dead-time voltage V DT , can be determined, for example, based on one or more of the following quantities: • Intermediate circuit voltage (see e.g. 114+115) • Current in the chokes of the phases or the neutral conductor of the PFC (e.g. the chokes to the left of the PFC in Fig. 6)

[0081] The information shown with arrow 116 can, for example, additionally or alternatively include information regarding the modulation-induced voltage (V). Mod ) of the rectifier.

[0082] According to the exemplary embodiments, both AC-side and DC-side measurement information can be used to reduce leakage currents. In particular, considering a grid-side measurement of a displacement voltage enables a significant reduction in leakage currents. This can be achieved, for example, by means of an additional measurement.

[0083] Furthermore, based on the measurement information 114 regarding the DC-side voltage between the positive terminal 131 of the rectifier and the DC link center of the rectifier, and / or using the measurement information 115 regarding the DC-side voltage between the DC link center of the rectifier and the negative terminal 132 of the rectifier, information about a common-mode component can be determined based on a topology and / or modulation of the rectifier 130, based on which, in turn, common-mode compensation (using control signal 111) and thus a reduction in leakage current can be enabled. For the sake of clarity, the DC link center of the rectifier is in Fig. 1 not shown.

[0084] As an optional feature, in Fig. Figure 1 also shows a possible DC-side load 140, e.g., a battery. Optionally, the reduction circuit can be configured to provide measurement information 141 regarding a load voltage, e.g., a battery voltage, e.g., V. B , to obtain and, based on the measurement information 141 (e.g., together with one or more of the information pieces 112, 113, 114, 115, 116), to provide the control signal 111. Corresponding configurations are described below using a battery voltage V as an example. B (as examples of a load voltage), see e.g. section “Fluctuation of the intermediate circuit voltage and DC source”, which is referred to in more detail.

[0085] In other words, a reduction circuit according to the exemplary embodiments can be designed to obtain a measured value of a DC voltage or battery voltage, and also to take into account the influence of such a DC voltage or battery voltage on voltage fluctuations for providing the control signal for reducing leakage currents, e.g., as shown below with derivations to V CY (with fluctuating DC voltage) discussed.

[0086] In general, a measurement of the load voltage, e.g. V, can be used. B , for example by means of measurements known in the prior art or already available in conventional approaches.

[0087] Based on Fig. 1. A further embodiment will be explained. A reduction circuit 110 according to exemplary embodiments can be configured to provide the control signal 111 (solely or additionally) based on measurement information 122 regarding (e.g., a mains-side measurement) a fault current. Fig. Measurement information 122 is derived from the supply signal 121 and can, for example, describe a fault current measurement, which includes, for instance, the sum of measured currents of all mains-side conductors except the protective earth (PE). The control signal 111 can thus be based solely on the fault current measurement 122 or with one or more of the information 112 to 116 and optionally also with information regarding the modulation-related voltage (V). Mod ) of the rectifier, be provided.

[0088] Fig. Figure 2 shows schematic, simplified circuit diagrams for a power factor rectifier (PFC), left, and a power factor rectifier (PFC) with an additional DC-DC converter, right, according to exemplary embodiments. Fig. Figure 2 shows a rectifier (PFC), 230, on the left. A load / source, 240, e.g., a battery, can be connected to the DC side. Optionally or alternatively, a DC-DC converter, 250, can be connected between the rectifier 230 and the load 240 (see Figure 2). Fig. 2 right). The DC-DC converter, 250, is transformerless (galvanically connected) and the negative terminal, 232, of the DC- voltage link is connected to the negative terminal of the battery 240. Alternatively, DC+, 231, can be connected to the positive terminal of the battery (as, for example, in Fig. 2 links). The electrical network 220 for supplying the rectifiers is shown as an example as a three-phase network with the conductors L''1, L''2 and L''3, as well as neutral conductor N and earthing point or protective conductor connection PE''.

[0089] When the voltage between DC- and PE'' or DC+ and PE'' changes, a current flows through the capacitors C due to the voltage change. Yp or C Yn (260). The capacitance of the Y-capacitors can be up to 4 µF for vehicle electrical systems, for example. iCYp=CYp⋅dVCYpdt or iCYn=CYn⋅dVCYndt

[0090] The sum of the currents i CYp and i CYn Leakage current flows through the protective conductor connection to PE. If a protective conductor break occurs, a touch voltage can appear on the previously grounded housing. At this point, Fig. 3 referred. Fig. Figure 3 shows a schematic view of the circuit. Fig. 2 right with body resistance R K in the event of an interruption of the protective conductor.

[0091] If a person touches the housing, the touch voltage leads to a touch current through the body resistance R. K , 270, of the person. A reduction in the voltage change of the capacitors C Yn and C Yn In this case, this leads to a reduction in the touch current.

[0092] The inventors recognized that a number of influencing factors can lead to a voltage change in the Y-capacitors on the DC side of the rectifier. These include: - net shape - Harmonics of the mains voltage and displacement voltage - Fluctuations in the intermediate circuit voltage and / or the DC source voltage - Dead time voltage of the rectifier semiconductors - Common-mode voltage of the PFC modulation - Common-mode voltage of the PFC filter choke

[0093] The aim of the methods described below, according to the exemplary embodiments, is therefore, for example, to compensate for the different common-mode voltages or common-mode disturbances and to reduce the resulting leakage current i. L and / or to avoid or reduce touch current.

[0094] In the Fig. 2 and Fig. Figure 3, as well as the following figures, also shows an optional residual current monitor unit (RCMU) that allows for optional fault current measurement, which will be discussed in more detail later. For example, the fault or differential current can be monitored using the RCMU. The corresponding measurement information can be calculated, for example, from the sum of the currents of all conductors except the protective earth (PE).

[0095] The control signal can therefore be provided based on a mains-side current measurement (especially a disturbance feedforward component). Network forms:

[0096] At the network connection on the consumer side L''1, L''2, L''3, L'' N A common-mode voltage can occur at the PE terminal due to unbalanced load impedances Z'', the short-circuit impedance of the power source, and the series impedances Z of the line. In a transformerless rectifier, this common-mode voltage can be transferred to the DC side and cause a voltage change across the capacitors C. Yp and C Yn and thus lead to leakage currents. At this point, we will refer to... Fig. 4 referred. Fig. Figure 4 shows schematic views of an equivalent circuit diagram, left, and of voltages, right, in the TN-CS three-phase four-wire system according to exemplary embodiments.

[0097] The displacement stress V NN'' is an example of a TN-S network in Fig. Figure 4 shows that in a TN system, the neutral conductor is connected to the protective conductor at the generator or transformer, N = PE. This results in, for example, a relatively small voltage difference V at the consumer. N''PE'' In a TT network, the grounding resistance between the operating earth and the system earth can lead to an increased voltage difference V. N''PE'' at the consumer. In an IT network, the insulation between N'' and PE'' can cause a voltage difference up to the level of the conductor-neutral voltage (V) in the event of a first insulation fault. LL / √3) occur. Regarding network configurations, which can be addressed with exemplary implementations, see below. Fig. 5 referred to. In other words, exemplary implementations for rectifier applications in a variety of network topologies, such as the one in Fig. Leakage currents are reduced in the 5 topologies shown, e.g. TN-C, TN-CS, TN-S, TT and IT topologies. Harmonics of the mains voltage and displacement voltage:

[0098] At this point, we will refer to Fig. 6 referred. Fig. Figure 6 shows a schematic view of a block diagram with voltage measurements for a rectifier according to exemplary embodiments. For simplification, as in Fig. 6. For the following illustrations, the mains connection is shown directly at the consumer (however, the implementation examples are not limited by such a simplification). The voltage difference V N''PE'' It is therefore drawn as an additional voltage source 601 (optional voltage measurements are marked with symbol 602). The following voltage measurements can be used (or may even be necessary) to compensate for the common-mode voltage of the mains voltage: Voltage measurement between each mains connection and earth potential PE'': Direct measurement: V 1''PE'' , V 2''PE'' , V 3''PE'' , V N''PE''

[0099] For the operation of the rectifier, measuring the line-to-neutral voltages can be used (or may even be necessary) to minimize the number of additional voltage measurements. The following approach uses the state-of-the-art line-to-neutral measurements with an additional voltage measurement V. N''PE'' can be used or is even preferable (e.g., to keep the (e.g., necessary) number of additional voltage measurements low).

[0100] Combined measurement via V N''PE'' V1''PE''=V1''N''+VN''PE'' V2''PE''=V2''N''+VN''PE'' V3''PE''=V3''N''+VN''PE'' VN''PE''=VN''PE''

[0101] Voltage between the mains connection and the center tap M of the intermediate circuit with C XM and separate voltage measurement V XM : V L1''X , V L2''X , V L3''X , V N''X , VXM with C XM and direct measurement: V L1''M , V L2''M , V L3''M , V N''M without CXM:VL1''M,VL2''M,VL3''M,VN''M

[0102] At this point, we will refer to Fig. 7 referred. Fig. Figure 7 shows a schematic view of a common-mode equivalent circuit for the phases and neutral conductors according to exemplary embodiments.

[0103] Fig. Figure 8 further shows a schematic view of a common-mode equivalent circuit for the phases and neutral conductors with direct measurement according to exemplary embodiments. In other words, it shows Fig. 8 The equivalent circuit diagram for the direct measurement of the voltage between L'' and M or N'' and M. In other words, exemplary implementations are not limited to a specific form of mains-side measurement. Therefore, both direct and combined measurement methods can be used.

[0104] The following are examples of calculation steps for determining the control signal according to exemplary implementations. In particular, examples of processing network-side measurements, e.g., in the form of voltages V, are presented below. 1''PE'' , V 2''PE'' , V 3''PE'' , and / or V 1''N'' , V 2''N'' , V 3''N'' , and revealed by DC-side measurements. Common-mode mains voltage and voltage difference V N''PE'' : - Example for determining the common-mode voltage V L''PE'' : VL''PE''(t)=V1''PE''(t)+V2''PE''(t)+V3''PE''(t)3 - Alternative determination by separate measurement and addition of the mains common-mode voltage and voltage difference V N''PE'' . VL''N''(t)=V1''N''(t)+V2''N''(t)+V3''N''(t)3 VL''PE''(t)=VL''N''(t)+VN''PE''(t)=V1''N''(t)+V2''N''(t)+V3''N''(t)3+VN''PE''(t)

[0105] Or, more generally, for the number n of phases of the grid connection: VL''PE''(t)=∑p=1nVL''pN''(t)n+VN''PE''(t) Internal voltage measurement: - Example for determining the common-mode component of the voltages between the network terminal L'' or N'' and the node M

[0106] With separate voltage measurement V XM : VL''M(t)=VL''1X(t)+VL''2X(t)+VL''3X(t)3+VXM(t) VN''M(t)=VN''X(t)+VXM(t)

[0107] Or more generally, for n conductors to the network connection: VL"M(t)=∑p=1nVL"pX(t)n+VXM(t) VN"M(t)=VN"X(t)+VXM(t)

[0108] Without separate voltage measurement V XM : VL"M(t)=VL"1M(t)+VL"2M(t)+VL"3M(t)3 VN"M(t)=VN"M(t)

[0109] Or more generally, for n conductors to the network connection: VL"M(t)=∑p=1nVL"pM(t)n VN"M(t)=VN"M(t) Fluctuations in the intermediate circuit voltage and DC source:

[0110] At this point, we will refer to Fig. 9 referred. Fig. Figure 9 shows schematic views of simplified equivalent circuit diagrams for a rectifier (PFC), left, and a rectifier (PFC) with an additional DC-DC converter, right, according to exemplary embodiments.

[0111] In Fig. Figure 9 shows a simplified equivalent circuit for the two partial voltages of the split DC link. A change in the voltage of the upper half V DC+M and a change in the lower half of V MDC- With a constant potential difference between M and PE'', a voltage change can occur across the Y-capacitors C. Yp and C Yn and thus lead to a current flowing through them. iCYp=CYp⋅(dVCdt+dVDC+Mdt) iCYn=CYn⋅(dVCdt−dVMDC−dt)

[0112] The goal is, for example, that the two streams i CYp and i CYnThe potential difference can be reduced to zero (or at least eliminated). This can be achieved by maintaining a constant potential difference between DC+ and PE'' or DC- and PE'', or by compensating the two currents.

[0113] By introducing a voltage V CY (also with V) C (e.g., as part of a control signal or generated by the control signal) between M and PE'', the goal of reducing leakage current for a fluctuating DC link voltage can be achieved. iL=iCYp+iCYn=0 VDC(t)=VDC+M(t)+VMDC−(t) CYp⋅(dVCYdt+dVDC+Mdt)+CYn⋅(dVCYdt−dVMDC−dt)=0 dVCYdt=CYndVMDC−dt−CYndVDC+MdtCYp+CYn

[0114] Since a constant voltage across the Y capacitors does not result in a leakage current, the calculation is only performed for the AC component. For the constant component V DC / 2 can be used, for example, as the setpoint of the DC link voltage regulator or an average of the measured value. VCY(t)=CYn(VMDC−(t)−VDC2)−CYp(VDC+M(t)−VDC2)CYp+CYn

[0115] For C Yp =C Yn results for V CY a simplified form of the above calculation. In this case, the following is used to calculate V: CY Only the measured value of the voltage of the upper and lower intermediate circuit halves is needed. VCY(t)=VMDC−(t)−VDC+M(t)2

[0116] The voltage V CY (including, for example, V) C (designated) takes into account, for example, the following influencing factors: Fluctuating total DC link voltage V DC (t) = V DC+M (t)+V MDC (t) Fluctuation of the partial voltages V DC+M (t) and V MDC- (t) Size of the Y-capacitance at the negative terminal C Yn and positive terminal C Yp

[0117] At this point, we will refer to Fig. 10 referred. Fig. Figure 10 shows further schematic views of simplified equivalent circuit diagrams for a rectifier (PFC), left, and a rectifier (PFC) with an additional DC-DC converter, right, according to exemplary embodiments.

[0118] For the variant with DC-DC converter, as described in Fig. As shown in Figure 10 on the right, for a constant battery or load voltage the Y-capacitance is combined at the negative terminal, since the DC component has no effect on the leakage current and a short circuit results for the AC component.

[0119] For a fluctuating battery or load voltage, the following results for V CY For example, the following calculation. VCY(t)=CYn(VMDC−(t)−VDC2)−CYp(−(VMDC−(t)−VDC2)+(VB(t)−VB))CYp+CYn

[0120] A reduction circuit according to the exemplary embodiments is therefore optionally designed to reduce the control signal (e.g., a disturbance feedforward component or a part of the disturbance feedforward component, e.g., V). CY ) based on measurement information regarding a load voltage, e.g. VB , , to provide a load located on a DC side of the transformerless rectifier.

[0121] For a constant battery or load voltage and C Yp =C Yn results for V CY a simplified form of the above calculation. In this case, V must CY e.g., only compensate for the fluctuation in the voltage of the lower half of the intermediate circuit. VCY(t)=VMDC−(t)−VDC2

[0122] In other words, a reduction circuit according to the exemplary embodiments can be designed to reduce the control signal based on • the measurement information regarding the DC-side voltage between the positive terminal of the rectifier and the intermediate circuit center of the rectifier, e.g. V DC+M (t), and / or • the measurement information regarding the DC-side voltage between the intermediate circuit center of the rectifier and the negative terminal of the rectifier, e.g. V MOC- (t)e.g. by means of • a difference formation, e.g. V MDC- (t)- V DC+M (t), and / or • a difference calculation weighted based on the capacitances of the Y capacitors, and / or • a determination of a deviation from a constant proportion V DC / 2 to determine.

[0123] For example, V can CY as compensation voltage for an alternating component of the voltage V MPE'' can be interpreted, for example, as the alternating component of the voltage V MPE'' .

[0124] It should be noted that V MPE'' For example, the voltage that actually / physically exists between nodes M and PE''. CY For example, this is a calculated quantity. The alternating component of V MPE'' It can be set up, or must be set up, exactly so that it V CY corresponds, or at least approximately corresponds (thus fulfilling the above formulas (e.g. the formulas from the section "Fluctuation of the intermediate circuit voltage and DC source:") and minimizing or at least reducing the leakage current).

[0125] Since V MPE'' can contain a DC component (a DC voltage offset) is V MPE'' not necessarily equal to V CY (or, for example, only in the special case where there is no equal share).

[0126] This V CY Part of the compensation voltage V CVM is modulated such that the alternating component between M and PE'' is exactly (or at least approximately) V CY This results in the above formulas being fulfilled (e.g., the formulas from the section "Fluctuation of the intermediate circuit voltage and DC source:").

[0127] The Fig. According to some exemplary embodiments, 7-10 and 12-13 are relevant only for the mathematical derivation; in a realization such as in Fig. 6 is, for example, no measurement (e.g., no direct measurement) for V CY available or necessary.

[0128] In summary, a reduction circuit can therefore be designed to reduce the control signal based on a difference between the measurement information V N''PE'' regarding the grid-side measurement of the displacement voltage and measurement information regarding (e.g. as an indirect measurement) an alternating component of a voltage V MPE''to determine the distance between the intermediate circuit center M and an earth potential PE'' of the rectifier.

[0129] It should be noted that, depending on the network configuration, the measurement information regarding the displacement stress may take a different concrete form. Dead time voltage of the semiconductors

[0130] The dead-time voltage of semiconductors in transformerless rectifiers can lead to common-mode interference and thus to leakage currents. Since this interference can contain relatively high frequency components, the resonant circuit, consisting of the rectifier's common-mode chokes and the total DC-side Y-capacitance, can be excited into oscillation. Due to the relatively low damping of this resonant circuit, this resonance can generate a significant portion of the leakage current.

[0131] The dead-time voltage can be determined or calculated for the individual phases using methods known in the prior art. In the prior art, the dead-time voltage is used to reduce harmonic components of the differential-mode current, thus improving the AC-side current quality.

[0132] The dead time voltage can be measured, for example, by means of • Two-level compensation • Linear compensation • Three-level compensation • TT compensation can be determined, see e.g. [2].

[0133] However, the inventors realized that this information could also be used to reduce leakage currents.

[0134] The common-mode component V can be determined from the calculated dead-time voltage for the individual phases. DTThe signal can be calculated and used, for example, to determine the drive signal. By applying appropriate interference during modulation, common-mode interference can be suppressed or at least reduced, and the excitation of the resonant circuit can be significantly reduced. This manifests itself, for example, in a substantial reduction of leakage current components in this frequency range.

[0135] If the dead-time voltage is not available for compensation, the controller described later still leads to a reduction in the disturbance, as the common-mode disturbance is regulated. However, since the controller can only react to a disturbance that has already occurred, the resonance effect, for example, is only reduced slightly or to a lesser extent. A combination of feedforward disturbance and control is therefore preferable.

[0136] In other words, exemplary implementations optionally include a disturbance feedforward based on the dead-time voltage. Common-mode component of the modulation

[0137] At this point, we will refer to Fig. 11 referred. Fig. Figure 11 shows schematic views of topologies according to exemplary implementations, namely an example of a two-level (left) and three-level topology (right). The voltage V Mod The relationship between node M* and M can or even must be considered for different circuit topologies. The goal is, for example, to determine the voltage V. Mod which, for example, represents a disturbance variable to compensate for. For a two-level topology as in Fig. 9 on the left is, for example, the voltage difference between the upper intermediate circuit half V DC+M and the lower half V MDC- dependent. The common-mode component of the modulation V ModIt can or even must be calculated and compensated (or at least reduced) to match the PFC circuit topology and modulation used. Due to the multitude of possible topologies and modulation methods, it is not possible to provide a universally valid formula. For the operation of a rectifier with a state-of-the-art control method, knowledge of the voltage V is required. Mod not required between node M* and M. Example of two-level modulation: VDC(t)=VDC+M(t)+VMDC−(t) D=VabcnVDC(t) / 2+12 VM∗DC−(t)=D⋅VDC(t)

[0138] For a voltage setpoint of zero volts, for example, V is used. DC (t) / 2 is defined by the two-level topology. If the stresses in the upper and lower halves of the intermediate circuit are different, the following stress difference V results. Mod . VMod(t)=VDC+M(t)−VMDC−(t)2 Example of three-level modulation: D=VabcnVMDC+(t) for Vabcn>0V D=VabcnVMDC−(t) for Vabcn<0V

[0139] For a voltage setpoint of zero volts, in a three-level topology with D = 0, the voltage M is output, and thus V is obtained. Mod = 0 V. For other topologies or modulation types, the calculation of V may or must be performed. Mod be adapted.

[0140] In other words, exemplary embodiments optionally include the determination of a modulation-dependent or topology-dependent component for determining the drive signal. This can be determined, as shown above, based on the measurement information regarding the DC-side voltage between the positive terminal of the rectifier and the DC link center point of the rectifier, and / or the measurement information regarding the DC-side voltage between the DC link center point of the rectifier and the negative terminal of the rectifier. Voltage across the filter choke

[0141] If this component is to be taken into account during compensation, the voltage V can be Ind For example, it can be calculated using the following calculation from the choke current measurement, the inductance value, and the resistance of the choke. VInd=R⋅i(t)+Ldi(t)dt Or more generally for n chokes or phases: VInd(t)=∑p=1n(Rp⋅ip(t)+Lp⋅dip(t)dt)n Since differentiating a measurement signal in practice is associated with high levels of interference / noise, this may need to be additionally filtered.

[0142] In other words, according to the exemplary embodiments, the control signal can therefore include a component that describes a common-mode voltage drop across a filter choke of the rectifier. Reduction processes:

[0143] The common-mode interference can be reduced by inverse modulation of the PFC with the compensation voltage V. CV compensated or at least reduced. This leads, for example, to a reduction in the voltage fluctuation of the Y-capacitors and thus to a reduction in the leakage currents or touch currents through the Y-capacitors. At this point, we will refer to... Fig. 12 referred. Fig. Figure 12 shows a schematic view of a common-mode equivalent circuit for operation without a neutral conductor according to exemplary embodiments.

[0144] To determine the necessary compensation voltage V CV can according to the Fig. 12. Using the mesh loop, the following equation for the phase voltages can be established. The voltage between node M and PE can be determined by the voltage V already introduced. CY (t) will be replaced. VN"PE"(t)+VL"N"(t)−VInd(t)−VDT(t)−VCV(t)−VMod(t)=VCY(t)

[0145] The external disturbances V N''PE (t), V L''N'' (t), V CY (t) and the disturbances V in the control loop Ind (t), V DT (t) and V Mod (t) can be compensated (e.g., individually or in combination) by feedforward interference. The necessary compensation voltage is thus, for example, as follows: VCV(t)=VN"PE"(t)+VL"N"(t)−VCY(t)−VInd(t)−VDT(t)−VMod(t)

[0146] The voltage measurement V L''M The voltage between the network connection L'' and the intermediate circuit center M allows for voltage regulation between these two nodes. At this point, Fig. 13 referred. Fig. Figure 13 shows a schematic view of a common-mode equivalent circuit for operation with a neutral conductor according to exemplary embodiments. The setpoint for the voltage V L''M can from Fig. 13 can be derived and corresponds to: VL"M∗(t)=VN"PE"(t)+VL"N"(t)+VCY(t)

[0147] For operation with a neutral conductor, e.g., single-phase or three-phase with neutral conductor, the mesh circulation can be set up: VN"PE"(t)−VInd(t)−VDT(t)−VCV(t)−VMod(t)=VCY(t)

[0148] The compensation voltage is therefore: VCV(t)=VN"PE"(t)−VCY(t)−VInd(t)−VDT(t)−VMod(t)

[0149] The setpoint of the controller is therefore: VN"M*(t)=VN"PE"(t)−VCY(t)

[0150] At this point, we will refer to Fig. 14 referred. Fig. Figure 14 shows a schematic view of a control structure of a leakage current reduction method (or, for example, the leakage current method according to the above explanations) according to exemplary embodiments.

[0151] Fig. Figure 14 shows a determination of a control signal according to exemplary embodiments with a multitude of optional features. Furthermore, it shows Fig. 14 an optional control device 1410, and an optional controller 1420 of a system according to exemplary embodiments.

[0152] Fig. Figure 14 shows the optional control device 1410, shown here as an example in the form of pulse width modulation (PWM), which is configured to control or regulate a rectifier (not shown) by means of a signal 1412 based on an input signal 1411. As an optional feature, a manipulated variable signal 1421 forms part of the input signal 1411, which is provided by the optional controller 1420, shown here as an example in the form of a differential mode (DM) current controller.

[0153] The controller shown here is an example. In the case shown, the controller 1420 comprises a control unit 1422, coordinate transformers 1423 (abc->dq) and 1424 (dq->abc), and a phase-locked loop 1425. However, other configurations of such a controller are also possible. For example, the controller 1420 receives, as optional features, current information 1426 in a dq coordinate system (e.g., in space vector representation) and in a three-phase coordinate system (abc), as well as information about the line voltages 1427. Based on this, the phase-locked loop 1425 provides corresponding angle information for the transformers 1423 and 1424, as well as the control unit 1422. As an example, the line voltage information 1427 is presented here in the three-phase coordinate system.

[0154] As in Fig. As shown in Figure 14, the mains voltage information 1427 can form part of a disturbance feedforward component 1431 of the control signal 1430 and thus a component of the input signal 1411.

[0155] As explained above, a control signal 1430, according to the exemplary embodiments, comprises a disturbance feedforward component 1431 and / or a control input component 1432. Therefore, it is possible to use either sole control via a disturbance feedforward component 1431 (with or without component 1427), or sole control without feedforward control via a control input component 1432', or a combination of feedforward control and control as in Fig. 14 shown.

[0156] An example of a disturbance feedforward component that can be used alone or in combination with signal 1427 is shown with signal 1441, here as example V CV .

[0157] As explained above, a reduction circuit according to exemplary embodiments is optionally designed to reduce the disturbance feedforward component 1431, and in particular 1441, based on • the measurement information 1446 regarding the network-side measurement of the displacement voltage, • the measurement information regarding the grid-side measurement of the zero-sequence voltage, • the measurement information regarding the DC-side voltage between the positive terminal of the rectifier and the intermediate circuit center of the rectifier, • the measurement information regarding the DC-side voltage between the intermediate circuit center of the rectifier and the negative terminal of the rectifier, and / or • to provide information 1443 regarding the common-mode component of the rectifier's dead-time voltage.

[0158] In addition, voltages 1445 from filter chokes of the rectifier, and / or voltages 1444 which are based on a circuit topology and / or modulation of the rectifier, can optionally or alternatively be taken into account.

[0159] For example, a corresponding voltage 1444 can be determined or at least approximated by calculating the difference between the terminals of the rectifier and the intermediate circuit center, see 1450. Since this influence, as in the context of Fig. 11 explains that, depending on the specific implementation, the following also applies: Fig. 14 shown implementation of the determination of V Mod to be understood as an example.

[0160] As in Fig. As shown in Figure 14, based on the measurement information regarding the DC-side voltage between the positive terminal of the rectifier and the intermediate circuit center of the rectifier, and the measurement information regarding the DC-side voltage between the intermediate circuit center of the rectifier and the negative terminal of the rectifier, a compensation voltage 1442 can be determined for the disturbance feedforward section 1441 (see Figures 1460 and 1470). The specific design may, in turn, depend on the specific design of the rectifier circuit, i.e., in particular, with or without a DC / DC converter. The approach shown in Figure 1470 for V CY This is to be understood as an example of an implementation where a constant load voltage can be assumed. Alternatively, a fluctuating load or battery voltage can also be taken into account, e.g., according to... VCY(t)=CYn(VMDC−(t)−VDC2)−CYp(−(VMDC−(t)−VDC2)+(VB(t)−VB))CYp+CYn.

[0161] Examples of implementations thus also allow for compensation of the effects of fluctuating load voltage on leakage currents.

[0162] Thus, the disturbance feedforward component, here as an example V CV , based on one of the following terms, where the individual summands and subtrahends are each individually optional, so that any combination of summands and subtrahends can be considered, e.g. as a trade-off regarding the effectiveness of leakage current reduction and the computational and measurement effort: VCV(t)=VN"PE"(t)+VL"N"(t)−VCY(t)−VInd(t)−VDT(t)−VMod(t) or VCV(t)=VN"PE"(t)−VCY(t)−VInd(t)−VDT(t)−VMod(t).

[0163] Another optional, or for example, also solely usable, contribution 1512 to the disturbance feedforward component 1431 can be based on measurement information regarding a fault current (I RCMU ) 1511, generated by means of an amplifier block 1510, to be used as a virtual resistor R VD to have an effect, as will be explained in detail below.

[0164] In addition to the optional determination of the disturbance feedforward component 1431 shows Fig. 14 further an example for the optional determination of a control variable component 1431 of the control signal 1430. For this purpose, a reduction circuit according to embodiments includes a controller 1480, here as an example in the form of a voltage regulator (e.g. CM - Common-Mode (common-switched) voltage regulator).

[0165] As explained above, the reduction circuit is designed, for example, to reduce the manipulated variable component 1432 based on a deviation, e.g., control deviation, between a setpoint value 1481, here as an example V, using controller 1480. L''M* , for the voltage between the mains connection and the intermediate circuit center and a measurement information 1482, here as an example V L''M or V N''M , regarding the voltage between the mains connection and the intermediate circuit center.

[0166] For the calculation of the target value 1481, the following can be used: • the network-side measurement information regarding the displacement voltage 1446, • the measurement information V CY1442, e.g., regarding the AC component of a voltage from Y-capacitors arranged on a DC side of the transformerless rectifier and / or e.g., regarding an AC component of a voltage between the intermediate circuit center M and an earth potential PE'' of the rectifier, and / or • a sum of measurement information regarding grid-side voltages, here used as an example in the form of a grid zero system voltage 1483.

[0167] In single-phase operation, the influence of the mains voltage can also be taken into account, for example, by means of a constant, see 1490.

[0168] For the control error, the reduction circuit can determine the measurement information 1482 regarding the voltage between the mains connection and the DC link center point with or without separate voltage measurements (as explained previously). Here too, exemplary implementations are not limited to a specific method of measurement; as shown in Box 1500, a different specific calculation basis can be used, for example, based on a single-phase or three-phase design.

[0169] In Fig. Figure 14 thus illustrates a possible implementation of the reduction method in a control structure. When calculating the voltage V CY (herein, for example, also as V) C (designated) a distinction can or even must be made, for example, between operation with and operation without a DC-DC converter. Regarding the values ​​for the mains zero system voltage V L''N'' and the measured value of the common-mode voltage V L''M''For example, the calculation may or even must be differentiated according to the number of phases and operation with / without a neutral conductor. All directly measurable disturbances, or those that can be directly calculated from a measurement, enable disturbance feedforward and thus a rapid response or compensation of the disturbances (or at least a reduction thereof).

[0170] Some of the disturbance variables, such as the voltage across the choke V, Ind (e.g., differentiation of the measurement signal is advantageous or even necessary here) or the common-mode component of the dead-time voltage cannot be determined with sufficient accuracy in some cases (e.g., under certain circumstances). If these are not pre-controlled by feedforward interference, these interference components cannot be determined by the voltage measurement V. L''M detected and compensated or at least reduced by the controller 1480.

[0171] The achievable dynamic range and bandwidth of the compensation depend (e.g., strongly) on the dimensioning of the rectifier's LC filter and the PFC's controller design. A high common-mode cutoff frequency of the filter (e.g., small inductance, small capacitance) XM These are advantageous. They can or even must be dimensioned within the overall system, including EMC interference suppression and controller design.

[0172] The method according to the exemplary embodiments works for all network types such as TN-CS, TN-TT, IT. In a TT network, a high voltage difference V can occur due to propagation resistance, or in an IT network due to an insulation fault. N''PE'' occur. The output-side intermediate circuit voltage of the rectifier V DC can or must, for example, depend on the voltage difference V. N"PE" and the network harmonics, if necessary, to a higher setpoint V DC*This needs to be regulated, for example, to allow sufficient reserve for common-mode voltage modulation. Previous implementations have shown that, for example, a setpoint V for a 400 V low-voltage network is required. DC* An increase of approximately 770 V, or approximately 120 V above the minimum value of 653 V, is sufficient. A mains voltage tolerance of ±10% and harmonics of the mains voltage according to EN 50160:1999 Table 1 were taken into account. A displacement voltage of 5% of the mains voltage was assumed.

[0173] For chargers with a 400 V battery or system voltage, common-mode modulation requires a control margin and therefore, for example, a higher DC link voltage than usual. This can slightly reduce the overall efficiency (PFC and DC-DC). With a charger for an 800 V battery or system voltage, the reduction method generally results in no or only a minimal increase in the required DC link voltage, as this is already determined by the high or higher battery voltage. VDC∗≥400V⋅1.1⋅23+120V=773V

[0174] A system according to the exemplary embodiments is therefore, for example, designed to determine a setpoint V. DC* for the intermediate circuit voltage of the rectifier as a function of the measurement information V N"PE" regarding the grid-side measurement of the displacement voltage V NN'' to adjust. At this point, we will refer to Fig. 22 referred.

[0175] Fig. Figure 22 shows a schematic view of an optional DC link voltage regulator 2210 according to exemplary embodiments, which is based on a setpoint for the DC link voltage V DC* a current setpoint I,dq* or I,dq (input into Fig. 14. top left) can be specified to regulate the intermediate circuit voltage.

[0176] The intermediate circuit voltage is therefore, for example, set to a target value (V). DC* ) regulated - e.g. either by the PFC (common) or by the DC-DC converter. V DC* The voltage is then determined, for example, as shown in the formula above, from the mains voltage + modulation reserve for common mode modulation (e.g. 120V).

[0177] According to exemplary embodiments, the voltage value of the total intermediate circuit voltage V can now be determined. DC to be increased - in order to enable higher Common Mode Modulation based on the measurement information V N"PE" regarding the grid-side measurement of the displacement voltage VNN'' . Simulation results:

[0178] The following simplified simulation model shows, as an example, the various common-mode disturbances and the resulting leakage current through the DC-side Y-capacitors. The reduction method uses the compensation voltage V to... CV the leakage current is reduced.

[0179] Since this is an idealized simulation, common-mode disturbances are already completely compensated by the feedforward disturbance. The effect of the dead-time voltage of the semiconductors and the filter choke, for example, cannot be represented in the simplified mean-value simulation model.

[0180] It will be on Fig. 15 referred. Fig. Figure 15 shows a schematic view of a simplified common-mode mean value simulation model according to exemplary implementations. Boundary conditions for example simulation: Störgröße Wert Harmonic or zero system of the mains voltage V GN'' 150 Hz mit 10V Amplitude Voltage V N"PE" (corresponds to the displacement stress V) NN" ) 50 Hz mit 10V Amplitude Voltage fluctuation, intermediate circuit voltage, upper half V DC+M lower half V MDC- 100 Hz mit 5V Amplitude 100 Hz mit 10V Amplitude Fluctuation of the DC source V B 100Hz mit 2V Amplitude

[0181] In the time range t = 0 to 0.05 s, the reduction method is not applied and a leakage current i is generated. L In the range t = 0.05 to 0.1 s, the reduction method is applied and compensated by the voltage V. CV will the leakage current i L reduced.

[0182] Fig. Figure 16 shows schematic views of simulation results for a simplified mean value model according to exemplary implementations. Laboratory measurement results:

[0183] The reduction process was tested with a prototype charger with an 11 kW output. At this point, we will refer to... Fig. 17 referred. Fig. Figure 17 shows a schematic view of a measurement setup for testing a reduction circuit according to exemplary embodiments. In other words, it shows Fig. 17. A concept circuit diagram for the test. For the test, as in Fig. Figure 17 shows a network simulator 1710 (Egston as an example) used for the targeted adjustment of the mains voltage harmonics and the displacement voltage. The network simulator 1710 thus provided, for example, the mains voltage and harmonics. The rectifier 1730 is implemented as an example in the form of an on-board charger (OBC). The battery was simulated by a bidirectional DC source 1720 (Regatron as an example). The DC-side Y-capacitors 1740 were replaced by optionally switchable (e.g., external) capacitors in two stages (C). Yp +C Yn = 2µF and C Yp +C Yn = 4µF). Furthermore, the structure includes Fig. 17 a measuring circuit 1750 for recording the measured value for the touch current. This is determined, for example, from the measured voltage according to the calculation rule from IEC 60990.

[0184] For the tests, the maximum harmonic voltage was set according to EN 50160 for the corresponding harmonics.

[0185] Odd harmonics: • Non-multiples of 3 (order h / uh in %): (5 / 6.00%), (7 / 5.00%), (11 / 3.50%), (13 / 3.00%), (17 / 2.00%), (19 / 1.50%) • Multiples of 3 (order h / uh in %) (3 / 5.00%), (9 / 1.50%), (15 / 0.50%) (21 / 0.75%) Straight harmonics • (Order h / uh in %): (2 / 2.00 %), (4 / 1.00 %)uh denotes the amplitudes (uh) of the harmonic voltage, relative to the fundamental frequency amplitude u1, where h is the order number of the harmonic voltage.

[0186] The following parameters were varied during the measurement: - Charging power: -100%, -50%, 0%, +50%, +100% - Displacement stress with 5% of the fundamental amplitude - Y-capacitor size: C Yp +C Yn= 2µF and C Yp +C Yn = 4µF - DC or battery voltage: 500V and 800V - Mains voltage: ◯ Basic measurement without harmonics and displacement voltage ◯ Displacement stress ◯ Odd harmonics which are non-multiples of 3 ◯ Odd harmonics which are multiples of 3 ◯ Even harmonics

[0187] The measurements were performed both without and with the reduction method activated. Fifty operating points resulted from varying the parameters. For the leakage current measurements, the frequency spectrum was determined for each operating point using an FFT transformation (e.g., Fast Fourier Transform), and the maximum of all 50 operating points was calculated. The measurement results of the 11kW charger prototype for single-phase and three-phase operation are presented in the Fig. 18, Fig. 19, Fig. 20 to Fig. 21 shown.

[0188] At this point, we will refer to the Fig. 18, Fig. 19, Fig. 20 to Fig. 21 referred. Fig. 18, Fig. 19, Fig. 20 to Fig. Figure 21 shows measurement results in the form of root mean square (RMS) leakage current spectra in mA over the frequency in Hz in the range from 10 Hz to 2 kHz.

[0189] Fig. Figure 18 shows a plot of measurement results for a leakage current spectrum for three-phase operation with C Yp +C Yn =2 µF for the measurement setup Fig. 17, according to exemplary embodiments.

[0190] Fig. Figure 19 shows a plot of measurement results for a leakage current spectrum for three-phase operation with C Yp +C Yn =4 µF for the measurement setup Fig. 17, according to exemplary embodiments.

[0191] Fig. Figure 20 shows a plot of measurement results for a leakage current spectrum for single-phase operation with C Yp +C Yn =2 µF for the measurement setup Fig. 17, according to exemplary embodiments.

[0192] Fig. Figure 21 shows a plot of measurement results for a leakage current spectrum for single-phase operation with C Yp +C Yn =4 µF for the measurement setup Fig. 17, according to exemplary embodiments.

[0193] As can be seen in the measurement results, in three-phase operation (see Fig. 18 and Fig. 19) a significant reduction in leakage currents for the harmonics of the mains voltage is achieved. The 50 Hz component resulting from the displacement voltage can also be reduced.

[0194] In single-phase operation, the leakage current component, which arises from the fluctuating power consumption at 100Hz and the resulting fluctuation of the DC link voltage, is also reduced.

[0195] The following section discusses in more detail the inventive approaches for common-mode resonance damping: At this point, we will refer to Fig. 23 referred. Fig. Figure 23 shows a schematic view of a block diagram with common-mode interference suppression chokes and differential-mode chokes for a rectifier with DC-DC converter according to exemplary embodiments.

[0196] The common-mode chokes (e.g., L) present in the rectifier (PFC) and (e.g., if present) DC-DC converter (DC-DC converter). CM1 , L CM2 , L CM3) and the parallel connection of the differential mode chokes (e.g., L1, L2, L3) can result in a total common mode inductance L CM to be summarized. The inductance L CM forms with the Y-capacitance C present on the DC side Y = C Yp +C Yn a series resonant circuit, or can be considered as such.

[0197] This series resonant circuit can be affected by a disturbance voltage V S be excited. The interference voltage V S It can be composed of various components, which include, for example, the common-mode voltage V on the mains side. L''PE'' (and / or displacement stress V) N''PE'' , zero-sequence voltage or mains voltage harmonics V L''N'' ) or the internal disturbances (e.g. dead time voltage V) DT , Common-mode voltage of the chokes V Ind , intermediate circuit voltage V DC+M or V MDC-contained (i.e., influenced or generated by the quantities). Since power electronic systems should exhibit low losses, the damping resistance R contained in the system is D of the resonant circuit is usually very small. (R D This can include, for example, conductor resistances, semiconductor on-resistance, and losses / core losses of inductors. The high quality factor resulting from the low damping resistance can lead to a strong resonance amplification and thus high leakage and touch currents in the resonance region.

[0198] This shows Fig. 24 a schematic view of a simplified equivalent circuit for the series resonant circuit comprising Y-capacitors 260 and filter chokes ΣL arranged on the DC side of the transformerless rectifier CM of the rectifier, according to exemplary embodiments.

[0199] By using a residual current sensor (also called: Residual Current Monitor Unit - RCMU, also fault current meter or differential current meter), the current (e.g. a differential current) of the series resonant circuit (which corresponds, for example, to the leakage current or touch current I) can be measured. RCMU = i L ) can be measured. The relationship of Ohm's law can be used to define a virtual resistance R. VD the voltage V VD will be calculated. VVD(t)=RVD⋅iRCMU(t)

[0200] The voltage V VD This represents a common-mode voltage, which is set via additional common-mode modulation of the rectifier. Different inductance values ​​are used in the specific dimensioning of the common-mode interference suppression chokes (e.g., L). CM1 , L CM2 , L CM3 with e.g. L CM = 2mH to 20mH) and the large range of Y-capacitance on the DC side (e.g. C) Yp+C Yn (200nF to 4µF) results in a wide frequency range for the resonance frequency f r For example, values ​​of 563 Hz to 7958 Hz. When selecting the fault current sensor and choosing the virtual resistance R VD It may be optional, or even necessary in some cases due to system delays (e.g., analog-to-digital converter, PWM output), to ensure the stability of the circuit. The integration of virtual damping into an overall system is exemplified in... Fig. 14 shown. Fig. 14 is the virtual resistance R to be set. VD , shown as element 1510, so that on the basis of the fault current measurement 1511, here as an example a disturbance feedforward part, a component 1511 of the control signal can be provided.

[0201] The connection of amplifier block 1510 from Fig. 14 with regard to the model of the resonant circuit, see Fig. 24, is in Fig. 25 highlighted. Fig. Figure 25 shows the schematic equivalent circuit diagram from Fig. 24 in the context of the regulation from Fig. 14, according to examples of implementation.

[0202] In Fig. Figure 26 shows a simulation result as an example (selected parameters see figure) for the virtual damping of the series resonant circuit. It can be seen that the fault current i RCMU and thus also the leakage current i L can be significantly reduced through virtual damping.

[0203] In summary, exemplary embodiments optionally include compensation for resonance effects due to the DC-side Y-capacitors and inductors, e.g., of rectifiers and / or DC-DC converters. Examples of such embodiments include, for instance, measuring the fault current and determining a compensation term 1512 based on the fault current measurement, e.g., by modeling the resonance behavior of the capacitors and inductors against the occurrence of leakage currents. For this purpose, a factor 1510 can be set, which, based on the current measurement 1511, can represent a virtual resistance to dampen the oscillation behavior and thus contribute to suppressing leakage currents. Further aspects of exemplary implementations:

[0204] Effects and advantages of exemplary implementations: Common-mode modulation of the PFC voltage significantly reduces the AC component of the voltage across the Y-capacitors. This reduces leakage currents through the grounding conductor. In the event of a broken protective conductor, the resulting touch voltages and currents are reduced.

[0205] A circuit, for example a reduction circuit according to exemplary embodiments, includes, for example in the sense of an analysis of the circuit: An optional voltage measurement for recording the common-mode voltage between the neutral conductor and earth potential, as well as an optional functionality for analyzing the rectifier's behavior based on measurements: This includes, for example, in particular, a measurement of the voltages in the system, e.g., sliding-mode voltage on the grid side, voltage between the phases and the DC link center point, DC link voltage and / or the common-mode voltage on the DC side (DC- to PE'' possibly additionally DC+ to PE'').

[0206] Examples of implementations include, for instance, an optional direct measurement of the DC-to-PE voltage or DC+-to-PE voltage. This measurement can, for example, include all influencing factors.

[0207] The problem, however, lies in the LC low-pass filter characteristics and the poor or difficult feedforward control and regulation of disturbances, especially for higher-frequency and / or dynamic disturbances. Accordingly, the above embodiments enable the reduction of leakage currents without the limitations of the LC low-pass filter characteristics, particularly with higher-frequency and / or dynamic disturbances.

[0208] According to the exemplary embodiments, this measurement information (e.g., DC- to PE'' or DC+ to PE'') can be used additionally or in parallel to the methods described herein or above, for example, to better compensate for static disturbances. The dynamic disturbances would be handled by the methods described herein or above.

[0209] In this approach, static disturbances can be compensated for, for example, with resonant controllers, as shown in the examples.

[0210] In general, a reduction circuit according to the exemplary embodiments is optionally designed to determine the control signal (e.g., in particular a disturbance component) based on measurement information regarding a voltage between the phases and the DC link center point, the DC link voltage, and / or the common-mode voltage on the DC side (DC- to PE, possibly also DC+ to PE), for example, using an additional controller. The additional controller can be connected in series or in parallel to a corresponding controller, as shown in Fig. 14 are shown arranged.

[0211] Based on this measurement information, the influence of a static disturbance variable can, for example, be reduced or compensated for.

[0212] Furthermore, a reduction circuit according to exemplary embodiments is optionally designed to reduce the control signal (e.g., in particular a disturbance component) based on measurement information or measurements regarding V. DC+PE'' and / the V DC-PE'' (and e.g. via invoices arising from this), and / or V MPE'' (e.g., in particular by means of DC-side, e.g., DC-side measurement of the AC component of V) MPE'' ) to determine (and e.g. based on the measurement information, e.g. V N''PE'' (regarding the grid-side measurement of the displacement voltage). Any influence of a potentially associated LC low-pass filter problem with its difficult controllability can be compensated for or reduced according to the procedure outlined in the exemplary embodiments.

[0213] In other words, the feedforward component of disturbances can be determined, for example, by V. N''PE'' and a DC-side measurement of the AC component, e.g., V MPE'' or via invoices from VDC+PE'' and V DC-PE'' be determined.

[0214] Examples of implementation address, among others, the following technical areas: - Common Mode Voltage (e.g., providing a control signal based on regulation and / or control of the common mode voltage to reduce leakage currents) - Zero system voltage (e.g., the use of displacement voltage and / or zero system voltage to provide the control signal, in particular a mains-side measurement of the displacement voltage) - Harmonics (e.g., in the sense of considering harmonics for determining the control signal to reduce leakage currents) - Modulation (e.g., modulation of the common-mode voltage to reduce leakage currents) - Leakage current (e.g., in the sense of reducing it) - Earth Current (e.g., in the sense of avoiding such currents) - Battery charger (e.g., in the sense that exemplary embodiments offer particular advantages for high-performance battery chargers, such as in the automotive sector, where high leakage currents can occur without the inventive control and / or disturbance feedforward)

[0215] Examples of implementation include, for example, compensation of the common-mode voltage (e.g., common-mode voltage + compensation).

[0216] Further examples of implementation include, for example, compensation based on the displacement voltage (e.g., displacement voltage measured on the grid side) (e.g., displacement voltage + compensation).

[0217] Further examples include, for instance, consideration of harmonics (e.g., mains-side harmonics) for the regulation and / or control of the common-mode voltage (e.g., harmonics + common-mode voltage).

[0218] Examples of implementation also include, for example, compensation of harmonics, e.g., common-mode voltage-relevant influences of harmonics (e.g., harmonics + compensation).

[0219] As previously explained, it should be mentioned again here that exemplary implementations enable a reduction of leakage currents in a wide variety of circuit and network configurations (e.g., network topologies). Among other things, these exemplary implementations enable a reduction of leakage currents for various circuit topologies / modulation types for the PFC semiconductors and for any number of phases (e.g., n phases), i.e., for example, in particular, 1 phase + neutral, 2 phases, 2 phases + neutral, 3 phases, 3 phases + neutral.

[0220] Furthermore, exemplary embodiments enable improved leakage current reduction by taking into account, in addition to the total voltage, also the partial voltages of the intermediate circuit halves and different Y-capacitances at DC- and DC+.

[0221] Furthermore, exemplary embodiments enable improved leakage current reduction in rectifier circuits with and without DCDC converters, as well as consideration of the DCDC converter to improve leakage current reduction.

[0222] Exemplary implementations enable improved leakage current reduction by measuring or calculating the disturbance variables for any number of phases, e.g. n phases (exemplars are therefore applicable to cases with any number of phases).

[0223] Exemplary implementations enable improved leakage current reduction by differentiating and considering PFC topologies. (As previously explained using 2- and 3-level topologies as examples. These exemplary implementations thus allow addressing of all or any topologies in general.)

[0224] Furthermore, exemplary embodiments can easily be applied to various use cases; for example, a distinction between live and neutral conductors is not strictly necessary in the different embodiments (single-phase with neutral conductor, three-phase with or without neutral conductor). Likewise, the same control structure can be used for different embodiments.

[0225] For example, according to the exemplary implementations, the voltage measurements are determined individually for each specific implementation or calculation (single-phase, three-phase, etc.) in order to improve leakage current reduction.

[0226] It is generally noted that, according to one embodiment of the invention, a distinction between conductor and neutral conductor and the various configurations (e.g., single-phase with neutral conductor, three-phase with or without neutral conductor) is not strictly necessary. This means that all related variations of applications can be addressed, for example, by utilizing the previously discussed specific features for each case. Thus, these embodiments allow for addressing many applications and therefore offer good flexibility. For example, when determining voltage measurements, attention can be paid to the specific implementation or calculation (e.g., single-phase, three-phase, etc.).

[0227] At this point, we would like to refer once again to the consideration of V according to the invention. Modreceived. In contrast to approaches where a fixed / direct connection of the neutral conductor, e.g. N, to the center point, e.g. M, prevails, these implementations allow the common-mode voltage to be modulated and other influencing factors (e.g., in addition to V) to be taken into account. Mod to compensate for or reduce these effects. Furthermore, exemplary implementations do not require additional compensation circuits, which involve further hardware and costs.

[0228] Inventive embodiments therefore allow for lower hardware costs and better effectiveness and flexibility through the possible consideration of further influencing factors, e.g. in contrast to an approach in which the voltages from DC+ to M and from M to DC- are only kept as constant as possible (i.e. only one possible ideal case described above (V)). DC+M =V DC-M ) is addressed by the voltage V Mod =0). List of abbreviations Abkürzung Beschreibung DC+ positives Potential / Anschluss des Zwischenkreises DC- negatives Potential / Anschluss des Zwischenkreises PE Erdungspunkt / -potential des Netzanschlusses, z.B. Betriebserder PE" Erdungspunkt / -potential des Gleichrichters, z.B. Schutzleiteranschluss imTNCS-Netz oder Anlagenerder im TT-Netz C Yp Sum of all Y-capacitors from DC+ to PE'' C Yn Sum of all Y-capacitors from DC to PE'' V CYp Voltage of the Y-capacitance C Yp V CYn Voltage of the Y-capacitance C Yn i CYp Leakage or touch current through capacitor C Yp i CYn Leakage or touch current through capacitor C Yn L Phase connection / voltage e.g. at the transformer transfer point L'' Phase connection / voltage at the connection point of the rectifier N Neutral conductor / voltage, e.g., at the transformer transfer point N'' Neutral conductor / voltage at the connection point of the rectifier V N"PE" Voltage difference between N'' and PE'' V DC+M Voltage of the upper intermediate circuit half between DC+ and M V MDC- Voltage of the lower intermediate circuit half between M and DC- V DC DC link voltage V DC = V DC+M + V MDC- V CY AC component of the voltage between the intermediate circuit center (M) and an earth potential (PE'') of the rectifier V CV Compensation voltage for the common-mode modulation of the PFC V L''N'' Common-mode component or zero-sequence voltage of the mains voltage at the PFC connection point V Ind Common-mode voltage of the voltage drop across the PFC chokes V DT Common-mode voltage of the dead-time compensation voltage of the PFC V Mod Common-mode voltage between nodes M* and M, taking into account the PFC topology (e.g., 2 levels or 3 levels) and the modulation method used. V L"M Common-mode voltage between the mains phases L'' at the connection point of the PFC and the node M V L''M * Controller setpoint of voltage V L''M V N"M Voltage between the neutral conductor N'' at the PFC connection point and node M V N"M* Controller setpoint of voltage VN "M uh Amplitudes (uh) of the harmonic voltage, relative to the fundamental frequency amplitude u1, where h is the order number of the harmonic voltage

[0229] Regarding V CY It should be noted that this can, for example, only be a calculated value for deriving control concepts according to exemplary implementations; it is not measured, or at least not directly measured. CY Theoretically, it can have a DC component, but this is not considered or is not relevant for leakage currents, for example. Implementation alternatives

[0230] All the materials, environmental influences, electrical properties and optical properties listed herein are to be regarded as examples and not as exhaustive.

[0231] Although some aspects have been described in connection with a device, it is understood that these aspects also constitute a description of the corresponding process, such that a block or component of a device can also be understood as a corresponding process step or as a feature of a process step. Similarly, aspects described in connection with or as a process step also constitute a description of a corresponding block, detail, or feature of a corresponding device. Some or all of the process steps can be performed 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 process steps can be performed by such an apparatus.

[0232] Depending on specific implementation requirements, embodiments of the invention can be implemented in hardware or in software. The implementation can be carried out using a digital storage medium, for example, a floppy disk, DVD, Blu-ray disc, CD, ROM, PROM, EPROM, EEPROM, FLASH memory, hard disk, or other magnetic or optical storage medium, on which electronically readable control signals are stored. These control signals can interact with, or interact with, a programmable computer system in such a way as to execute the respective method. Therefore, the digital storage medium can be computer-readable.

[0233] Some embodiments according to the invention therefore include a data carrier which has electronically readable control signals which are able to interact with a programmable computer system in such a way that one of the methods described herein is carried out.

[0234] 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 in carrying out one of the methods when the computer program product runs on a computer.

[0235] The program code can also be stored on a machine-readable medium, for example.

[0236] Other embodiments include the computer program for carrying out one of the methods described herein, wherein the computer program is stored on a machine-readable medium.

[0237] In other words, an embodiment of the method according to the invention is thus a computer program that includes program code for carrying out one of the methods described herein when the computer program runs on a computer.

[0238] Another embodiment of the methods 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. The data carrier, the digital storage medium, or the computer-readable medium is typically tangible and / or non-perishable or non-temporary.

[0239] 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 sequence of signals can be configured, for example, to be transferred via a data communication connection, such as the Internet.

[0240] Another embodiment comprises a processing device, for example a computer or a programmable logic device, which is configured or adapted to perform one of the methods described herein.

[0241] Another embodiment comprises a computer on which the computer program for performing one of the procedures described herein is installed.

[0242] Another embodiment of the invention comprises a device or 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, for example, electronic or optical. The receiver can be, for example, a computer, a mobile device, a storage device, or a similar device. The device or system can, for example, include a file server for transmitting the computer program to the receiver.

[0243] In some embodiments, a programmable logic device (for example, a field-programmable gate array, an FPGA) can be used to perform some or all of the functionalities of the methods described herein. In some embodiments, a field-programmable gate array can interact with a microprocessor to perform one of the methods described herein. Generally, in some embodiments, the methods are performed by any hardware device. This can be general-purpose hardware such as a computer processor (CPU) or method-specific hardware such as an ASIC.

[0244] The devices described herein can be implemented, for example, using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

[0245] 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).

[0246] The methods described herein can be implemented, for example, using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

[0247] The methods described herein, or any components thereof, may be executed at least partially by hardware and / or by software.

[0248] The embodiments described above merely illustrate the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be obvious to other people skilled in the art. Therefore, it is intended that the invention be limited only by the scope of protection set forth in the following claims and not by the specific details presented herein by way of description and explanation of the embodiments. References [1] DE 10 2017 216 468 A1 2019.03.21 Disclosure document Conti Temic microelectronic GmbH, 90411 Nuremberg, DE [2] Performance of Dead-Time Compensation Methods in Three-Phase Grid-Connection Converters, TOMOYUKI MANNEN and HIDEAKI FUJITA Tokyo Institute of Technology, Japan, Electrical Engineering in Japan, Vol. 198, No. 2, 2017 [3] Strothmann, B., Keuck, L., & Bolte, S. (2021). Highly efficient, durable and compact GaN-based power electronics for the electromobility of the future (HELENE): Collaborative project: Project completion report: Sub-project of the University of Paderborn, Department of Power Electronics and Electrical Drives: Circuits and controls for GaN-based on-board power converters. [University of Paderborn, Department of Power Electronics and Electrical Drives]. https: / / doi.org / 10.2314 / KXP:1777923433 QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 2009 / 0121805 A1

[0005] US 10,069,480 B2

[0005] DE 10 2017 216 468 A1

[0248] Cited non-patent literature

[0000] TOMOYUKI MANNEN and HIDEAKI FUJITA Tokyo Institute of Technology, Japan, Electrical Engineering in Japan, Vol. 198, No. 2, 2017

[0248] Strothmann, B., Keuck, L., & Bolte, S. (2021

[0248]

Claims

Reduction circuit (110) for a transformerless rectifier (130, 230, 250, 1730) for reducing leakage and / or touch currents, wherein the reduction circuit is configured to provide a control signal (111, 1430, 1431, 1432, 1441) for the rectifier, and wherein the reduction circuit is configured to provide the control signal, based on at least one of the following: measurement information (112, 1446, VN''PE'') regarding a line-side measurement of a displacement voltage (VNN''), measurement information (113, 1483) regarding a line-side measurement of a zero-sequence voltage (VL''N''), measurement information (114) regarding a DC-side voltage (VDC+M), between a positive terminal (131, 231, DC+) of the rectifier and an intermediate circuit center (M) of the rectifierto provide measurement information (115) regarding a DC-side voltage (VMDC-) between the intermediate circuit center (M) of the rectifier and a negative terminal (132, 232, DC-) of the rectifier, and / or information (116, 1443) regarding a common-mode component of a dead-time voltage (VDT) of the rectifier, and / or information regarding a modulation-induced voltage (VMod) of the rectifier. Reduction circuit (110) according to claim 1, wherein the reduction circuit is configured to provide the control signal (111, 1430, 1431, 1432, 1441) with a disturbance feedforward component (1441, VCV, 1431) that is based on at least one of the measurement information (112, 1446, VN''PE'') regarding the mains-side measurement of the displacement voltage (VNN''), the measurement information (113, 1483) regarding the mains-side measurement of the zero-sequence voltage (VL''N''), the measurement information (114) regarding the DC-side voltage (VDC+M) between the positive terminal (131, 231, DC+) of the rectifier (130, 230, 250, 1730) and the intermediate circuit center (M) of the rectifier, the measurement information (115) regarding the DC-side voltage (VMDC-) between the intermediate circuit center (M) of the rectifier (130, 230, 250, 1730) and the negative terminal (132, 232, DC-) of the rectifier,the information (116) regarding the common-mode component of the dead-time voltage (VDT) of the rectifier (130, 230, 250, 1730), and / or the information regarding the modulation-induced voltage (VMod) of the rectifier. Reduction circuit (110) according to claim 2, wherein the reduction circuit is configured to determine the disturbance feedforward component (1441, VCV, 1431) based on a component (1444, VMod) of a common-mode voltage of the rectifier, which is based on a circuit topology and / or modulation of the rectifier (130, 230, 250, 1730), and wherein the reduction circuit is configured to determine the component of the common-mode voltage, which is based on the circuit topology and / or modulation of the rectifier (130, 230, 250, 1730) based on the measurement information (115) regarding the DC-side voltage (VMDC-) between the intermediate circuit center (M) of the rectifier and the negative terminal (132, 232, DC-) of the rectifier, and / or the measurement information (114) regarding the DC-side voltage (VDC+M) to be provided between the positive terminal (131, 231, DC+) of the rectifier and the intermediate circuit center of the rectifier. Reduction circuit (110) according to one of claims 2 to 3, wherein the reduction circuit is configured to provide the disturbance feedforward component (1441, VCV, 1431) based on a component (1445, VInd) of a common-mode voltage of the rectifier, which is based on an influence of a filter choke of the rectifier (130, 230, 250, 1730). Reduction circuit (110) according to one of claims 2 to 4, wherein the reduction circuit is configured to reduce the disturbance feedforward component (1441, VCV, 1431) based on a difference between the measurement information (112, 1446, VN''PE'') regarding the mains-side measurement of the displacement voltage and measurement information or information (VCY) derived from a measurement regarding an AC component of a voltage from Y-capacitors (260, 1740) arranged on a DC voltage side of the transformerless rectifier (130, 230, 250, 1730); and / or based on a difference between the measurement information (112, 1446, VN''PE'') regarding the grid-side measurement of the displacement voltage and a measurement information or information (VCY) derived from a measurement regarding an AC component of a voltage (VMPE'') between the DC link center (M) and an earth potential (PE'') of the rectifier. Reduction circuit (110) according to one of the preceding claims, wherein the reduction circuit is configured to provide the control signal (111, 1430, 1432, 1441) with a control variable component (1432, u), wherein the reduction circuit is configured to obtain a setpoint (1481, VL''M*) for a voltage between a mains connection of the rectifier (130, 230, 250, 1730) and the DC link center (M) of the rectifier on the DC side of the rectifier, and wherein the reduction circuit is configured to provide the control variable component based on a deviation between the setpoint (1481, VL''M*) for the voltage between the mains connection and the DC link center (M) and a measurement information (1482, VL''M, VN''M) regarding the voltage between the mains connection and the DC link center (M). Reduction circuit (110) according to claim 6, wherein the reduction circuit is configured to determine the setpoint (1481, VL''M*) for the voltage between the mains connection of the rectifier (130, 230, 250, 1730) and the intermediate circuit center (M) of the rectifier. Reduction circuit (110) according to one of claims 6 to 7, wherein the reduction circuit is configured to reduce the setpoint for the voltage (1481, VL''M*) between the mains connection of the rectifier (130, 230, 250, 1730) and the intermediate circuit center (M) of the rectifier based on a difference between the measurement information (112, 1446, VN''PE'') with respect to the mains-side measurement of the displacement voltage (VNN''), and a measurement information or information (VCY) derived from a measurement with respect to an AC component of a voltage of Y-capacitors (260, 1740) arranged on a DC voltage side of the transformerless rectifier (130, 230, 250, 1730);and / or based on a difference between the measurement information (112, 1446, VN''PE'') regarding the grid-side measurement of the displacement voltage (VNN''), and measurement information or information (VCY) derived from a measurement regarding an AC component of a voltage (VMPE'') between the DC link center (M) and an earth potential (PE'') of the rectifier. Reduction circuit (110) according to claim 8, wherein the reduction circuit is configured to determine the setpoint for the voltage (1481, VL''M*) between the mains connection of the rectifier (130, 230, 250, 1730) and the DC link center (M) of the rectifier based on measurement information regarding one or more voltages (V1''PE'', V2''PE'', V3''PE'') between one or more mains connections of the rectifier (130, 230, 250, 1730) and an earth potential (PE'') of the rectifier, and / or measurement information regarding one or more voltages (V1''N'', V2''N'', V3''N'') between one or more mains connections of the rectifier (130, 230, 250, 1730) and a neutral conductor. Reduction circuit (110) according to one of claims 8 or 9, wherein the reduction circuit is configured to reduce the measurement information or the information (VCY) derived from a measurement regarding the AC component of the voltage of the Y-capacitors (260, 1740) arranged on the DC side of the transformerless rectifier (130, 230, 250, 1730) and / or the measurement information or the information (VCY) derived from a measurement regarding the AC component of the voltage (VCY) between the DC link center (M) and an earth potential (PE'') of the rectifier based on the measurement information (114) regarding the DC-side voltage (VDC+M) between the positive terminal (131, 231, DC+) of the rectifier and the DC link center (M) of the rectifier.to determine the measurement information (115) regarding the DC-side voltage (VMDC-) between the intermediate circuit center (M) of the rectifier and the negative terminal (132, 232, DC-) of the rectifier, and / or information regarding the capacitances (CYp, CYn) of the Y capacitors. Reduction circuit (110) according to claim 1, wherein the reduction circuit is configured to provide the control signal (111, 1430, 1432, 1441) with a disturbance feedforward component (1441, VCV, 1431) that is based on at least one of the measurement information (112, 1446, VN''PE'') regarding the mains-side measurement of the displacement voltage (VNN''), the measurement information (113, 1483) regarding the mains-side measurement of the zero-sequence voltage (VL''N''), the measurement information (114) regarding the DC-side voltage (VDC+M) between the positive terminal (31, 231, DC+) of the rectifier (130, 230, 250, 1730) and the intermediate circuit center of the rectifier, the measurement information (115) regarding the DC-side voltage (VMDC-) between the intermediate circuit center (M) of the rectifier (130, 230, 250, 1730) and the negative terminal (132, 232, DC-) of the rectifier,the information (116) regarding the common-mode component of the dead-time voltage (VDT) of the rectifier (130, 230, 250, 1730), and / or the information regarding the modulation-induced voltage (VMod) of the rectifier; and wherein the reduction circuit is configured to provide the control signal (111, 1430, 1432, 1441) with a control variable component (1432, u), wherein the reduction circuit is configured to obtain a setpoint (1481, VL''M*) for a voltage between a mains connection of the rectifier (130, 230, 250, 1730) and the DC link center (M) of the rectifier on the DC side of the rectifier, and wherein the reduction circuit is configured to adjust the control variable component based on a deviation between the setpoint (1481, VL''M*) for the voltage between the mains connection and the DC link center (M) and a measurement information regarding the voltage (1482, VL''M,VN''M) between the grid connection and the intermediate circuit center (M). Reduction circuit (110) according to one of the preceding claims, wherein the reduction circuit is configured to provide the control signal (111, 1430, 1431, 1432, 1441) based on measurement information regarding one or more voltages (V1''PE'', V2''PE'', V3''PE'') between one or more mains terminals of the rectifier (130, 230, 250, 1730) and an earth potential (PE'') of the rectifier, and / or measurement information regarding one or more voltages (V1''N'', V2''N'', V3''N'') between one or more mains terminals of the rectifier and neutral conductor, and / or measurement information regarding one or more voltages between one or more mains terminals of the rectifier (130, 230, 250, 1730) and an intermediate circuit center point of the rectifier. Reduction circuit (110) according to one of the preceding claims, wherein the reduction circuit is configured to determine the control signal (111, 1430, 1431, 1432, 1441) based on at least one of the following: measurement information regarding a voltage (VDC+PE'') between the positive terminal (131, 231, DC+) of the rectifier (130, 230, 250, 1730) and the earth potential (PE'') of the rectifier, measurement information regarding a voltage (VDC-PE'') between the negative terminal (132, 232, DC-) of the rectifier and the earth potential (PE'') of the rectifier, and / or measurement information regarding a voltage between the intermediate circuit center (M) of the rectifier and the earth potential (PE'') of the rectifier. Reduction circuit (110) according to one of the preceding claims, wherein the reduction circuit is configured to provide the control signal (111, 1430, 1431, 1432, 1441) based on measurement information (141) regarding a load voltage (VB) from a load (140, 240) arranged on a DC voltage side of the transformerless rectifier (130, 230, 250, 1730). Reduction circuit (110) according to one of the preceding claims, wherein the reduction circuit is configured to provide the control signal (111, 1430, 1431, 1432, 1441) based on measurement information (122) regarding a fault current (IRCMU). Reduction circuit (110) for a transformerless rectifier (130, 230, 250, 1730) for reducing leakage and / or touch currents, wherein the reduction circuit is configured to provide a control signal (111, 1430, 1431, 1432, 1441) for the rectifier, and wherein the reduction circuit is configured to provide the control signal based on measurement information (122) regarding a fault current (IRCMU). Reduction circuit (110) according to claim 15 or 16, wherein the reduction circuit is configured to provide a disturbance feedforward component (1441, VCV, 1431) of the control signal (111, 1430, 1431, 1432, 1441) based on the measurement information (122) regarding the fault current (IRCMU). Reduction circuit (110) according to one of claims 15 to 17, wherein the measurement information (122) regarding the fault current (IRCMU) is a sum of measured currents of all network-side conductors except for a protective conductor (PE). Reduction circuit (110) according to one of claims 15 to 18, wherein the reduction circuit is configured to provide the control signal (111, 1430, 1431, 1432, 1441) based on a model of the influence of a series resonant circuit comprising Y-capacitors (260, 1740) and filter chokes of the rectifier (130, 230, 250, 1730) arranged on the DC side of the transformerless rectifier (130, 230, 250, 1730); to a common-mode voltage of the rectifier by means of the measurement information (122) regarding the fault current (IRCMU). Reduction circuit (110) according to claim 19, wherein common-mode interference suppression chokes and / or differential-mode chokes of the rectifier are taken into account for the series resonant circuit, Reduction circuit (110) according to one of claims 16 to 20, wherein the reduction circuit is configured to provide the control signal (111, 1430, 1431, 1432, 1441) based on measurement information (112, 1446, VN''PE'') regarding a network-side measurement of a displacement voltage (VNN''). Reduction circuit (110) for a transformerless rectifier (130, 230, 250, 1730) for reducing leakage and / or touch currents, wherein the reduction circuit is configured to provide a control signal (111, 1430, 1431, 1432, 1441) for the rectifier, and wherein the reduction circuit is configured to provide the control signal based on measurement information (112, 1446, VN''PE'') regarding a mains-side measurement of a displacement voltage (VNN''). System comprising a reduction circuit (110) according to one of claims 1 to 22, the transformerless rectifier (130, 230, 250, 1730) and a control device (1410), wherein the control device is configured to control the rectifier based on an input signal (1411); a controller (1420) for providing a control signal (1421) for controlling a mains current and / or the DC link voltage of the rectifier; wherein the system is configured to provide a combination of the control signal and the control signal (111, 1430, 1431, 1432, 1441) as an input signal for the control device. System according to claim 23, wherein the system is configured to adjust a setpoint for the DC link voltage of the rectifier (130, 230, 250, 1730) depending on the measurement information (112, 1446, VN''PE'') regarding the network-side measurement of the displacement voltage (VNN''). Method for a transformerless rectifier (130, 230, 250, 1730) for reducing leakage currents and / or touch currents, wherein the method has the following features: providing a control signal (111, 1430, 1431, 1432, 1441) for the rectifier based on at least one of the following: measurement information (112, 1446, VN''PE'') regarding a line-side measurement of a displacement voltage (VNN''), measurement information (113, 1483) regarding a line-side measurement of a zero-sequence voltage (VL''N''), measurement information (114) regarding a DC-side voltage (VDC+M) between a positive terminal (131, 231, DC+) of the rectifier and an intermediate circuit center (M) of the rectifier, measurement information (115) regarding a DC-side voltage (VMDC-) between the Intermediate circuit center (M) of the rectifier and a negative terminal (132, 232, DC-) of the rectifier,information (116) regarding a common-mode component of a dead-time voltage (VDT) of the rectifier, and / or information regarding a modulation-induced voltage (VMod) of the rectifier. Method for a transformerless rectifier (130, 230, 250, 1730) for reducing leakage currents and / or touch currents, wherein the method has the following features: providing a control signal (111, 1430, 1431, 1432, 1441) for the rectifier based on measurement information regarding a fault current (IRCMU). Computer program with program code for carrying out the method according to claim 25 or 26, when the program runs on a computer.

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