DE102020131512A1 - Device for generating a compensation current - Google Patents

Abstract

A device (20) for generating a compensation current (62) in a supply network (10) with a voltage regulation device (30), a compensation current generating device (60), a first point (50), at least two terminals (21, 24) and one Proposed protective conductor connection (25), wherein the voltage control device (30) is designed to regulate a first voltage (U50) at the first point (50) to a second voltage (U2) at the protective conductor connection (25), and wherein a compensation current generating device (60) is designed to generate a compensation current (62) between the protective conductor connection (25) and the first specified point (50) as a function of a compensation current specification signal (I_COMP_S).

Description

The invention relates to a device for generating a compensation current.

the US 2011/0057707 A1 shows a multiplexer with leakage current detection.

the US 2014/0327371 A1 shows a power supply for an LED with phase control and compensation.

the U.S. 2016/0154047 A1 shows leakage current detection with a test circuit.

the US2013/0043880A1 shows a device for determining and compensating for a fault current.

It is therefore an object of the invention to provide a new device for generating a compensation current.

The object is solved by the subject matter of claim 1.

A device for generating a compensation current in a supply network has a voltage regulation device, a compensation current generation device, an AC/DC converter, a first point, at least two terminals and a protective conductor terminal, which AC/DC converter is connected to the two terminals on the AC side and has a first direct current line and a second direct current line on the direct current side, which voltage control device is designed to regulate a first voltage at the first point to a second voltage at the protective conductor connection, which voltage control device has at least two current control devices for influencing the first voltage at the first point are assigned, which current control devices are each connected to an assigned connection and to the first point and are designed to cause a current flow between the first point depending on an assigned control signal and to enable or prevent the associated connection, which current control devices at least partially have a voltage limiter, which voltage limiter has a transistor and a drive device for driving the transistor, which drive device has a first side and a second side that is galvanically isolated from the first side by a first galvanic isolating device side, which control device is connected to the first direct current line and the second direct current line on the first side, which control device is designed to enable energy transmission from the first side to the second side via the first galvanic isolating device and on the second Page to generate a drive voltage for the voltage limiter, and which compensation current generating device is designed to, depending on a compensation current default signal, a compensation current between the Schu tzconductor connection and the first specified point.

A virtual neutral conductor is thus provided by the voltage regulation device at the first point, and a compensation current can be generated easily and reproducibly via this due to the small voltage difference between the protective conductor connection and the first point.

According to a preferred embodiment, the voltage regulation device has a comparator which is designed to compare the first voltage and the second voltage with one another. This is a preferred solution for determining a control deviation. A comparator is preferably used as the comparator, since this enables a particularly fast comparison.

According to a preferred embodiment, at least two current control devices, more preferably at least three current control devices, are assigned to the voltage control device for influencing the voltage at the first point.

Incorporating a larger number of current control devices may improve voltage regulation on some utility grids.

According to a preferred embodiment, the device has a battery, which battery is connected on the DC side of the AC/DC converter. This enables a safe power supply or power supply.

According to a preferred embodiment, at least one of the current control devices has a switch arrangement, which switch arrangement comprises a first switch, which switch arrangement can be controlled by the associated control signal and is designed to enable a current flow between the first point and the associated connection in a first state, and in a second state, preventing current flow between the first point and the associated terminal. The current control device can advantageously be controlled by the switch arrangement.

According to a preferred embodiment, the switch arrangement is designed to influence the size of the current flow in the first state as a function of the control deviation of the voltage control device. As a result, the voltage can be regulated with a comparatively rapid response.

According to a preferred embodiment, the voltage regulation device is connected to the switch arrangement via at least one second galvanic isolating device, which second galvanic isolating device is preferably designed as an optocoupler or as a transformer. The galvanic isolation means that complex driver stages between the voltage regulation device and the switch arrangement can be avoided.

According to a preferred embodiment, the switch arrangement has a second switch, which second switch is connected in parallel with the first switch. The provision of a second switch facilitates control by a hardware control device of the voltage regulation device.

According to a preferred embodiment, the voltage regulation device is designed to influence the current flow via the first switch when the phase at the associated connection has a positive half-cycle and to influence the current flow via the second switch when the phase at the associated connection has a negative half-cycle . This makes it easier to control the switches.

• - einen Stromfluss von mindestens einem der Brückengleichrichteranschlüsse zur ersten Leitung zu ermöglichen, aber einen Stromfluss von der ersten Leitung zu den Brückengleichrichteranschlüssen zu verhindern,
• - einen Stromfluss von der zweiten Leitung zu mindestens einem der Brückengleichrichteranschlüsse zu ermöglichen, aber einen Stromfluss von den Brückengleichrichteranschlüssen zur zweiten Leitung zu verhindern,
• - im ersten vorgegebenen Zustand der Schalteranordnung einen Stromfluss zwischen dem ersten Brückengleichrichteranschluss und dem zweiten Brückengleichrichteranschluss in mindestens eine Richtung zu ermöglichen, und
• - im zweiten vorgegebenen Zustand der Schalteranordnung einen Stromfluss zwischen den zwei Brückengleichrichteranschlüssen zu verhindern. Durch diese Verschaltung fließt der Strom immer in der gleichen Richtung durch die Schalteranordnung, und es können unidirektionale Schalter verwendet werden, insbesondere elektronische Schalter.

According to a preferred embodiment, at least one of the current control devices has a bridge rectifier, which bridge rectifier has a first bridge rectifier connection, a second bridge rectifier connection, a first line, a second line and the switch arrangement, which first bridge rectifier connection is connected to the associated connection, which second bridge rectifier connection is connected to the first point is connected, which bridge rectifier is designed to

• - allow current flow from at least one of the bridge rectifier terminals to the first line, but prevent current flow from the first line to the bridge rectifier terminals,
• - allow current flow from the second line to at least one of the bridge rectifier terminals, but prevent current flow from the bridge rectifier terminals to the second line,
• - to allow a current flow between the first bridge rectifier connection and the second bridge rectifier connection in at least one direction in the first predetermined state of the switch arrangement, and
• - to prevent a current flow between the two bridge rectifier terminals in the second predetermined state of the switch arrangement. As a result of this interconnection, the current always flows through the switch arrangement in the same direction, and unidirectional switches, in particular electronic switches, can be used.

According to a preferred embodiment, at least one of the current control devices is designed to enable a current flow between the first point and the associated connection in both directions. This allows the point to be connected to the associated port regardless of the voltage at those points and the voltage at the associated port can be used when needed.

According to a preferred embodiment, a capacitor is connected in parallel with at least one of the current control devices. The capacitor is particularly advantageous when a low voltage is present at the terminals of the current control devices, since only little current can flow via the current control device in this state. As a result, a compensation current can also flow well in this state.

According to a preferred embodiment, the device has at least one voltage measuring device, which voltage measuring device is designed to detect a measured voltage value that characterizes the voltage as a function of the voltage at at least one of the terminals, and the voltage control device is designed to control the current control devices as a function of the measured voltage value head for. The measured voltage values can advantageously be used to decide which of the current control devices are suitable for influencing the voltage at the first point.

According to a preferred embodiment, the device is set up to turn on the current control device assigned to this connection when a connected neutral conductor is detected at one of the connections in order to bring about a permanent connection of this connection to the first point. According to a preferred embodiment, in this case the current control device assigned to this connection is switched on independently of the first voltage at the first point. In such a case can the neutral conductor can be used directly as a "virtual" neutral conductor. If further current control devices are present, these are preferably switched off.

According to a preferred embodiment, the voltage control device has a first voltage regulator and a second voltage regulator, and the voltage control device activates either the first voltage regulator or the second voltage regulator depending on the measured voltage value. This results in a clear assignment of the voltage regulator to the voltage measurement values.

According to a preferred embodiment, the at least one voltage measuring device comprises a first voltage measuring device and a second voltage measuring device, and the voltage control device is designed to control the current control devices depending on the difference between the measured voltage value of the first voltage measuring device and the measured voltage value of the second voltage measuring device. Forming the difference or considering the sign of the difference advantageously enables the device to be used for different voltage supplies.

According to a preferred embodiment, the connections have a first connection and a second connection, which can be connected to a supply network during operation in such a way that a first phase is connected to the first connection and a second phase is connected to the second connection, the second phase being phase-shifted by 180° to the first phase is. In such a supply network, the generation of the voltage at the first point by the voltage regulation device is particularly advantageous, since there is often no neutral conductor connection.

According to a preferred embodiment, the device has a control device, and the current control devices at least partially have at least one control circuit, which at least one control circuit is designed to switch the associated current control device on or off, depending on a control device signal from the control device to allow a neutral wire to be connected to the first point. If the supply network provides a neutral conductor, this can be connected directly to the first point. The control circuits can be used to switch the device on or off directly via a control device, which can output a TTL signal or another signal to the control circuits, for example. In addition, the same switch can be used as in normal operation. Alternatively an additional switch could be provided but this is not required.

According to a preferred embodiment, the current control devices are controlled as a function of the voltage at at least one of the terminals.

According to a preferred embodiment, the current control devices are controlled as a function of the voltage difference between the first voltage and the second voltage.

• 1 eine Vorrichtung zur Erzeugung eines Kompensationsstroms mit einer Spannungsregelungsvorrichtung und Stromsteuervorrichtungen,
• 2 ein Diagramm mit einer Differenzspannung zwischen zwei Phasen, aufgetragen über die Zeit,
• 3 ein Kompensationsstromvorgabesignal, aufgetragen über die Zeit,
• 4 ein Diagramm mit der Spannung an einem Punkt, aufgetragen über die Zeit,
• 5 ein Diagramm mit einem durch die Stromsteuervorrichtungen von 1 erzeugten Strom,
• 6 eine Ausführungsform der Stromsteuervorrichtung von 1,
• 7 eine weitere Ausführungsform der Vorrichtung zur Erzeugung eines Kompensationsstroms, welche für ein dreiphasiges Versorgungsnetz oder für ein einphasiges Versorgungsnetz geeignet ist,
• 8 eine Tabelle mit einer Auswahllogik für ein Versorgungsnetz vom Typ US split phase,
• 9 eine Tabelle mit einer Auswahllogik für ein Versorgungsnetz mit einer Phase L1 und einem Neutralleiter N,
• 10 eine Tabelle mit einer alternativen Auswahllogik für ein Versorgungsnetz mit einer Phase L1 und einem Neutralleiter N,
• 11 eine weitere Ausführungsform der Stromsteuervorrichtung von 1,
• 12 eine weitere Ausführungsform der Vorrichtung zur Erzeugung eines Kompensationsstroms,
• 13 eine Ausführungsform der Spannungsregelungsvorrichtung von 1 zur Ansteuerung der Vorrichtung von 12, und
• 14 eine Ausführungsform einer Ansteuervorrichtung von 11.

Further details and advantageous developments of the invention result from the exemplary embodiments described below and illustrated in the drawings, which are in no way to be understood as limiting the invention, and from the dependent claims. It shows

• 1 a device for generating a compensation current with a voltage regulation device and current control devices,
• 2 a diagram with a differential voltage between two phases, plotted over time,
• 3 a compensation current specification signal plotted over time,
• 4 a graph of the voltage at a point plotted against time,
• 5 a diagram with a through the current control devices of 1 generated electricity,
• 6 an embodiment of the current control device of FIG 1 ,
• 7 a further embodiment of the device for generating a compensation current, which is suitable for a three-phase supply network or for a single-phase supply network,
• 8th a table with a selection logic for a US split phase type supply network,
• 9 a table with a selection logic for a supply network with a phase L1 and a neutral conductor N,
• 10 a table with an alternative selection logic for a supply network with a phase L1 and a neutral conductor N,
• 11 another embodiment of the current control device of FIG 1 ,
• 12 a further embodiment of the device for generating a compensation current,
• 13 an embodiment of the voltage regulation device of FIG 1 for controlling the device from 12 , and
• 14 an embodiment of a control device from 11 .

The figures are described coherently and comprehensively. Like reference numerals identify like elements, and these will typically be described only once.

1 shows a device 20 for generating a compensation current 62. The device 20 has a connection 21 with a line 51, a connection 24 with a line 54 and a protective conductor connection 25 with a line 55. The protective conductor connection 25 is connected to a protective conductor symbol 99, which also is used elsewhere in the circuit as a symbol for a conductive connection to the protective conductor terminal 25.

By way of example, the device 20 is connected to a split-phase type power supply network 10, such as is used in particular in the United States. Such a supply network 10 is also referred to as a single-phase three-wire network. A point 13 is connected to terminal 21 (HOT1) via a first AC voltage source 11 and to terminal 24 (HOT2) via an AC voltage source 12. The point 13 is grounded via a ground terminal 199 and connected to the protective conductor terminal 25 (PE). The AC voltage sources 11, 12 are, for example, the secondary side of a transformer and the point 13 is a center tap on the secondary side.

An AC/DC converter 190 is connected, for example, via a line 151 to the connection 21, via a line 154 to the connection 24 and via a line 155 to the protective earth connection 25 and can thus draw power from the supply network 10 or from the supply network 10 are fed. A direct current line 191 and a direct current line 192 are provided on the direct current side of the AC/DC converter 190, and the direct current lines 191, 192 are connected—possibly via a DC/DC converter (not shown) provided for voltage adjustment - A battery 194 and a consumer 15 connected.

A differential current detection device 17 is provided and measures the differential current in the supply lines 151, 154 of the phases to the AC/DC converter 190, which characterizes the leakage currents that occur. The resulting residual current measurement signal can, for example, be converted in the residual current detection device 17 into a compensation current specification signal I_COMP_S, which characterizes the level of the required compensation current 62 . The level of the compensation current can be up to 150 mA (effective value), for example. The conversion can be carried out, for example, by simple inversion, or more complicated calculations can be carried out using Fourier transformation and filtering to generate the compensation current specification signal I_COMP_S.

The device 20 has a voltage regulation device 30, a compensation current generation device 60, a first point 50 and two current control devices 41, 42. The current control devices 41, 42 are each connected to an associated terminal 21, 24 on the one hand and to the first point 50 on the other hand and are designed to to allow a current flow 141, 142 between the first point 50 and the associated terminal 21, 24.

When speaking of a flow between two points in this application, this includes a flow in both directions. On the other hand, when speaking of a flow from a point A to a point B, it only includes a direction from point A to point B.

The compensation current generation device 60 is designed to generate the compensation current 62 between the protective conductor connection 25 and the first specified point 50 as a function of the compensation current specification signal I_COMP_S. The compensation current specification signal I_COMP_S is preferably generated by the differential current detection device 17 and fed to the compensation current generation device 60 via a line 18 . If, on the other hand, the magnitude of the leakage currents that occur are known or can be determined in some other way, the compensation current specification signal I_COMP_S can be generated in a different way.

The voltage regulation device 30 has a comparator 30A and the actual voltage regulator 30B. The voltage control device 30 is connected on the input side via a line 251 to the point 50 and to the protective conductor connection 25 (protective conductor symbol 99), and the voltage control device 30 can thus carry out a comparison between a first voltage U50 at the first point 50 and a second voltage U25 at the protective conductor connection 25 . A signal U_DIFF, which characterizes the control difference, is generated at the output of the comparator 30A. The signal U_DIFF is fed to the voltage regulator 30B. The tension control device 30 a selection device 32 is assigned. The selection device 32 can also be considered part of the voltage regulation device 30 . The selection device 32 has two voltage measuring devices 35 , 36 . The voltage measuring device 35 is connected to the terminal 21 via a line 33 and designed to generate a value characterizing the voltage U21 at the terminal 21, and the voltage measuring device 36 is connected to the terminal 24 via a line 34 and to detect the voltage U24 at the terminal 24 characterizing value formed. The selection device 32 is connected to the current control devices 41, 42 via lines 243, 244 and, depending on the values of the voltage measuring devices 35, 36, determines through which current control device 41, 42 a suitable current can flow in order to adjust the voltage at point 50 to the voltage approach the protective conductor connection 25.

A control device 400 is preferably provided, which is connected to a measuring point 401 on the line 51 , to a measuring point 404 on the line 54 and to a measuring point 405 on the line 55 . The control device 400 can detect via the measuring points 401, 404, 405 whether a neutral conductor N is connected to one of the conductors 51, 54. In addition, the control device 400 enables a monitoring of the protective conductor connection PE on the line 55 and, if necessary, a measurement of a loop resistance. The control device 400 can also be integrated into the selection device 32 .

2 shows a diagram in which the difference U21-U24 of the voltage U21 at connection 21 and the voltage U24 at connection 24 is plotted over time t as line 181. Since the phases HOT1 (U21) and HOT2 (U24) have a phase shift of 180° in a supply network of the US split phase type, the amplitude of the difference U21 - U24 corresponds to twice the amplitude of the voltage U21. In the exemplary embodiment, the amplitude of the voltage difference U21-U24 is 350 V. The time from time t0 to time t2 is approximately 20 ms, and at time t1 a zero crossing of voltage U21 and voltage U24 occurs. This corresponds to a frequency of 50 Hz, but frequencies of 60 Hz are also possible.

3 shows with the line 182 an example of a compensation current specification signal I_COMP_S, as it is from the residual current detection device 17 of FIG 1 is produced. The compensation current generation device 60 should preferably generate a compensation current 62 which is proportional to the compensation current specification signal I_COMP_S. In the exemplary embodiment, the consumer 15 or the AC/DC converter 190 causes 1 a sinusoidal leakage current which has a higher frequency than the frequency of phase HOT1.

4 shows the voltage U50 at point 50. In the simulation carried out, the voltage U50 plotted as line 183 fluctuates sinusoidally with an amplitude of 80 mV. The fluctuation in the voltage U50 results from the compensation current 62 generated by the compensation current generation device 60. The voltage regulation device 32 is at best able to keep the voltage U50 at exactly 0 mV when the compensation current 62 is constant. With a time-dependent
Compensation current specification signal I_COMP_S, on the other hand, will always have a certain fluctuation in voltage U50 despite the voltage regulation. However, the amplitude of the voltage U50 of 80 mV can be compared with the amplitude of the phase HOT1 of 175 V and is therefore very small. The low voltage U50 has a great advantage in generating the compensation current 62 through the
Compensation current generating device 60. The
Compensation current generation device 60 itself can be operated with a comparatively low voltage (eg 10 V or 20 V), so no large or powerful power pack is required. In addition, the potential difference between the voltages U25 and U50 is low, and this makes it easier to impress the desired compensation current, since this does not have to be impressed once at, for example, 0 V and once at 120 V potential difference, depending on the connected phase. In addition, the regulation of the voltage U50 by the voltage regulator 30 is more economical than providing different voltages for the voltage regulator 30.

5 12 shows the current generated by the current controllers 41 and 42. FIG. A line 184 is drawn at a current of 0 mA. Between time t0 and time t1, phase HOT1 has a negative half cycle and phase HOT2 has a positive half cycle. Therefore, in this time window, the positive half-waves of the current 185 are generated by the current control device 42 and the negative half-waves are generated by the current control device 41 . In the time window from time t1 to time t2, phase HOT1 is positive and phase HOT2 is negative. Therefore, in this time window, the positive half cycles of the current 185 are effected via the current control device 41 and the negative half cycles are effected by the current control device 42 .

6 shows an embodiment of the current control device 41. The current control device 42 is preferably constructed in the same way. The current control device 41 is connected to the terminal 21 on the one hand and to the point 50 on the other hand. The terminal 21 is connected to a point 113 directly or indirectly (e.g. via a resistor). Point 113 is connected through a diode 101 to a line 111 and through a diode 102 to a line 112. Line 111 is connected through a diode 103 to a point 114 and line 112 is through a diode 104 to point 114 tied together. Point 114 is connected to point 50 via a resistor 115 .

The line 111 is connected to the line 112 via a voltage limiter 45 and a switch arrangement 47 . A setpoint value U_S, which specifies the maximum voltage at the switch arrangement 47, is supplied to the voltage limiter 45 via a line 46. The switch arrangement 47 has a switch 48 which can be controlled via a galvanic isolating device 49 . The switch arrangement 47 has an input 43A and an input 43B, via which the galvanic isolating device 49 can be controlled. In the exemplary embodiment, the galvanic isolating device 49 is designed as an optocoupler. Training as a transformer is also possible.

Diode 101 is forward-biased from point 113 to line 111 and diode 103 is forward-biased from point 114 to line 111 . A current can thus flow from terminal 21 to line 111 and a current from point 50 to line 111. However, the diodes 101, 103 prevent a current in the reverse direction.

Diode 102 allows current from line 112 to terminal 21 and diode 104 allows current from line 112 to point 50. Current in the reverse direction, however, is prevented by diodes 102 and 104, respectively.

In other words, the cathodes of diodes 101, 103 are connected to line 111 and the anodes of diodes 102, 104 are connected to line 112. As a result, the diodes 101, 102, 103, 104 form a bridge rectifier 100.

The switch arrangement 47 is designed to enable a current flow from the line 111 to the line 112 in a first state Z1 and to interrupt the current flow from the line 111 to the line 112 in a second state Z2.

In the exemplary embodiment, the switch 48 is unidirectional, and the bridge rectifier 100 ensures that the switch 48 is only operated in the forward direction. If a bidirectional switch arrangement 47 is used, the bridge rectifier 100 can be omitted and the bidirectional switch arrangement 47 is connected between the connection 21 and the point 50 .

7 shows a further exemplary embodiment of the device 20 for generating a compensation current 62 (cf. 1 ). In addition to the connections 21, 24 and 25, additional connections 22 and 23 are provided. It is possible to connect phases HOT1 and HOT2 to terminals 21 and 24 as in 1 to connect. In the present exemplary embodiment, however, a supply network 10 with the phases L1, L2, L3, a neutral conductor N and a protective conductor PE is provided. Phase L1 is connected to terminal 21, phase L2 to terminal 22, and phase L3 to terminal 23. Neutral conductor N is connected to terminal 24, and protective conductor PE is connected to protective conductor terminal 25. Compared to the embodiment of 1 Additional lines 152 and 153 are provided to allow AC/DC converter 190 to be connected to phases L2 and L3. The device 20, on the other hand, does not necessarily need a connection to the phases L2, L3, so that the basic circuit of the device can remain unchanged in the case of the supply network 10 with three phases. The differential current detection device 17 determines the differential current of all active conductors L1, L2, L3, N.

It is also possible to use the device 20 for a single-phase connection to the supply network 10, in which case the connection 21 can be connected to the phase L1 and the connection 24 to the neutral conductor N, or vice versa.

8th FIG. 12 shows the selection logic of the selection device 32 when the device 20 is connected to a US split phase type supply network 10 with the phases HOT1 and HOT2. The voltage U21 at terminal 21 corresponds to the voltage of the HOT1 phase, and the voltage U24 at terminal 24 corresponds to the voltage of the HOT2 phase. Since the HOT2 phase has a phase shift of 180° with respect to the HOT1 phase, the sign of the HOT2 phase is opposite to that of the HOT1 phase. A positive voltage is represented by a plus sign and a negative voltage by a minus sign. The third column shows the difference U21 - U24 between the voltage U21 and the voltage U24. Due to the phase shift of 180°, the sign of the difference U21 - U24 corresponds to the voltage U21.

In the fourth column, the difference U25 - U50 is shown, as determined by the comparator 30A of 1 is determined. A positive difference (+) therefore means that the voltage at point 50 is lower than the voltage at the protective conductor connection 25. Therefore, a current must flow from one of terminals 21, 24 to point 50 for voltage regulation. Since a corresponding current can flow during the positive half-wave of the HOT1 phase, the current control device 41 is switched on (“41 ON”). If, on the other hand, the difference U25 - U50 is negative in the positive half-wave of the HOT1 phase, the voltage at point 50 is too high, and in the positive half-wave of the HOT1 phase there is a connection to the HOT2 phase by activating the current control device 42. At the negative Half-wave of the HOT1 phase, the activation of the current control devices 41, 42 are reversed accordingly.

Instead of the difference U25 - U50, the difference U50 - U25 can of course also be used, with the signs changing accordingly from plus to minus or minus to plus. This follows from the fact that the difference is: $$\text{U50}-\text{U25}=-\left(\text{U25}-\text{U50}\right).$$

9 shows the selection logic of the selection device 32 for connecting the device 20 to a supply network 10 with a phase L1 and a neutral conductor N. The voltage U21 (phase L1) has a positive half-cycle (+) and a negative half-cycle (-). The neutral conductor N or the voltage U24 has a voltage of approx. 0 V relative to the protective conductor PE or to the connection 25. The sign of the voltage difference U21 - U24 also corresponds to the sign of the voltage U21. The current control device 41 or 42 can be selected in the same way by considering the difference U25-U50 on the one hand and the voltage U21 or the voltage difference U21-U24 on the other hand and corresponds to the described selection of 8th .

In some single-phase supply networks 10, for example in Germany with claims L1 and N, it is not always clearly specified by the plug whether the respective connections are connected to L1 and N or vice versa. The device 20 also works when the neutral conductor N is present at terminal 21 and the phase L1 is present at terminal 24. In order to achieve this, the voltage U24 can be used for selection by the selection device 32 in such a case, or the possibility of evaluating the difference U21 - U24 is possible, which also occurs when the phase L1 and the neutral conductor N are swapped over to form a usable result.

The selection logic works regardless of whether additional phases L2, L3 are present or not.

10 12 shows an alternative selection logic for the selection device 32 when a neutral conductor N is connected to one of the terminals 21, 24. In the exemplary embodiment, phase L1 is connected to terminal 21, and voltage U21 therefore has a positive half-cycle (+) and a negative half-cycle (-). The neutral conductor N is connected to terminal 24, and the voltage U24 is therefore approximately 0 volts. It can be like 9 the difference U21 - U24 can be calculated, and together with the difference U25 - U50 a selection can be made as in 9 take place. However, since the neutral conductor N is already a connection with a low voltage, when the connection of the neutral conductor N is detected, the current control device 41 or 42 assigned to the corresponding connection can alternatively be switched on, and this also sets the point 50 to a voltage which is close to the voltage of the protective conductor connection 25. In the exemplary embodiment, the neutral conductor N is connected to the terminal 24, and the current control device 42 is therefore permanently switched to the on state.

11 12 shows a concrete embodiment of the current control device 41 of FIG 6 . In the following only the differences apply 6 received. In addition to the first switch 48, the switch arrangement 47 has a second switch 148. The switches 48 and 148 are connected in parallel with one another. A galvanic isolation device 149 is associated with the switch 148 and corresponding control terminals 143A and 143B are provided.

The voltage limiter 45 has a field effect transistor (FET) 160 whose drain terminal D is connected to the line 111 and whose source terminal S is connected to a point 161. The point 161 is connected via a resistor 162 to the switch arrangement 47. The gate G of FET 160 is connected to line 46 . A capacitor 165 is preferably provided between point 161 and line 46 . Preferably, a diode 164 is connected across capacitor 165 with the anode connected to point 161 . The diode 164 acts as additional protection for the gate terminal G. The line 46 is connected to the line 112 via a drive device 166, which drive device 166 serves as a voltage source for the transistor 160. A Schottky diode (not shown) can preferably be used as the diode 164, possibly without the capacitor 165. Schottky diodes enable a very fast switching speed and thus improve the voltage limitation. As an alternative to the field effect transistor 169, another switch can be used, for example a bipolar transistor. However, a field effect transistor is advantageous for high currents.

During operation, the drive device 166 generates a predetermined voltage, for example 5 V. If the voltage at the source terminal S is also 5 V, the gate-source voltage is 0 V and the FET 160 is blocked. On the other hand, if the voltage at point 161 is less than the voltage on line 46, a current will flow through FET 160, thereby increasing the voltage at point 161. This will regulate the voltage between point 161 and line 112 to 5 volts, or 5 volts . limited.

The switches 48 and 148 preferably have a largely proportional transmission ratio with a predetermined gain. The voltage between the connections 43A and 43B or the voltage between the connections 143A and 143B determine the current strength of the current flowing through the switches 48 or 148 with the predetermined transformation ratio.

The provision of the two switches 48 and 148 is not absolutely necessary from a technical point of view, but it facilitates activation by the selection device 32 of FIG 1 .

12 shows an embodiment of the device 20, in which the current control devices 41, 42 as in FIG 11 described a switch arrangement 47 with two switches 48, 148 have. The design of the current control device 41 corresponds to the embodiment of FIG 11 , wherein the voltage limiter 45 is shown schematically. The design of the current control device 42 also corresponds to the embodiment of FIG 11 , the difference being that the connections 43A, 43B on the optocoupler 49 are reversed. Thus, when terminal 43A is more positive than terminal 43B, switch 48 of current controller 41 conducts and switch 48 of current controller 43 is blocked, and vice versa. Likewise, the terminals 143A, 143B of the current controller 42 are reversed compared to the terminals 143A, 143B of the current controller 41. This ensures that at most one of the switches 48 of the current control devices 41, 42 can be activated by the signal at the connections 43A, 43B, and at most one of the switches 148 of the current control devices 41, 42 can be activated by the signal at the connections 143A, 143B will.

A capacitor 133 is connected in parallel with the current control device 41 , and a capacitor 134 is connected in parallel with the current control device 42 . The capacitors 133, 134 also enable a current to flow through the compensation current generating device 60 when the phase present at the terminals 21, 24 is just passing through zero. In this case, the required current flow cannot be guaranteed or can only be guaranteed with a low current intensity via the current control devices.

13 12 shows an embodiment of the voltage regulation device 30 and the selection device 32 of FIG 1 , which are designed to cooperate with the embodiment of 12 are trained.

The upper part of the circuit 30, 32 is denoted by 200A and the lower part of the circuit by 200B. The upper part 200A will be described below, and the lower part 200B may have the same structure.

The upper part 200A has a comparator 201, an optocoupler 208 with a diode 215 and a switch 204, a diode 203, an optocoupler 209 with a diode 213 and a switch 207, a diode 206, a comparator 210, a first drive circuit 218 with a connection 219, a second control circuit 220 with a connection 221 and a resistor 212.

The voltage U21 of the connection 21 is present at the plus input of the comparator 210, ie at the non-inverting input, and the voltage U24 of the connection 24 is present at the minus input, ie at the inverting input. The output 211 of the comparator 210 is connected to the protective conductor symbol 99 via the resistor 212, the diode 213, a line 214 and the diode 215. The anodes of the diodes 213, 215 point towards the output 211 of the comparator 210.

The plus input of comparator 201 is connected to point 50, so that voltage U50 is present. The minus input of the comparator 201 is connected to the connection 143A and via a resistor 216 to the protective conductor symbol 99, so that the voltage U25 of the protective conductor connection 25 is present. The output 202 of the comparator 201 is connected to a line 205 via a diode 203 and a switch 204 connected in anti-parallel to diode 203, and the line 205 is connected via diode 206 and a switch 207 connected in anti-parallel to diode 206 to terminal 143B.

A first drive circuit 218, which can be driven via a connection 219, is preferably provided between resistor 212 and diode 213, and a second drive circuit 220, which can be driven via a connection 221, is preferably provided between point 50 and comparator 201.

The lower part 200B of the circuit 30, 32 has a comparator 301, a diode 303, a Optocoupler 308, a diode 306, an optocoupler 309, a resistor 312, a resistor 316, a comparator 310, a first drive circuit 318 with a connection 319 and a second drive circuit 320 with a connection 321. These components correspond to the components 201, 203, 208, 206, 209, 212, 216 and 210, 218, 219, 220, 221, the reference numbers are therefore increased by the number 100 for the lower components. The interconnection of these components corresponds to the interconnection of the upper part 200A. In contrast to the upper part 200A, however, the assignment is reversed at the comparator 310, i.e. the voltage U24 is at the plus input and the voltage U21 is at the negative input of the comparator 310. In addition, the connection 143A of the upper part is provided in the lower part as 43B, and the terminal 143B of the upper part is provided in the lower part as 43A. The second drive circuit 320 has a different structure than the second drive circuit 220.

functionality

The voltage U21 and the voltage U24 are compared via the comparator 210 of the upper part 200A. If the voltage U21 is greater than the voltage U24, a current can flow through the diodes 213, 215, and the optocouplers 208, 209 are activated. This comparison U21 - U24 thus corresponds to the third column in the selection logic of FIG 8th until 10 . The upper part of the circuit 30, 32 is, for example, with a connection of the US split phase ( 8th ) is responsible for the positive half-wave of the HOT1 phase, and since the inputs of the comparator 310 are swapped over in the lower part compared to the upper part, the lower part of the circuit 30, 32 is responsible for the negative half-wave of the HOT1 phase.

The comparator 201 carries out a comparison between the voltage U50 at point 50, which is present at the non-inverting input, and the protective conductor voltage U25 at the protective conductor connection 25 plus the voltage drop across the resistor 216 as a result of a current 1201, which is present at the inverting input of the comparator 201, and the comparator 201 produces the current 1201 at the output 202 depending on the result of this comparison.

mit R216: Widerstand 216The comparator 201 thus results in the voltages at the inputs being matched to one another. So it applies $$\text{U50}=\text{U25}+\text{I201*R216}$$

with R216: resistor 216

This results in the stream 1201 to $$\text{I201=}\left(\text{U50}-\text{U25}\right)\text{/R216}$$

A current I201, which is proportional to the voltage difference U50-U25, is thus produced as a control value at the output 202 of the comparator 201. If the voltage U50 is greater than the voltage U25, a current can flow from the comparator 201 via the line 202, the diode 203, the line 205 and the switch 207 to the terminal 143B when the upper part of the circuit 30, 32 through the comparator 210 is activated, ie when there is a positive half-wave at phase HOT1.

As a result, the potential at terminal 143B is greater than that at terminal 143A. This has the power control devices 41, 42 of 12 the effect that the switch 148 of the current control device 41 is blocked due to the diode in the optocoupler 149, but that the switch 148 of the current control device 42 is turned on because the diode of the optocoupler 149 is arranged in the forward direction there. This leads to a current flow via the second current control device 42, and since there is a negative half-wave at the terminal 24, the voltage U50, which was too high, can be reduced.

If, on the other hand, the voltage U50 is lower than the voltage U25, the comparator 201 generates a negative voltage at the output 202 compared to the plus input, and a current can flow from the connection 143B via the diode 206, the line 205 and the switch 204 (at a positive half-wave) flow to the comparator 201. As a result, the switch 148 of the current control device 41 is turned on, and since there is a positive half-wave at the terminal 21, the voltage U50, which was too low, can be increased. The switch 148 of the power controller 42 remains locked.

The lower part 200B of the circuit 30, 32 functions accordingly, being only active when the HOT1 phase has a negative half-cycle or when the voltage U24 is greater than the voltage U21. The lower part 200B controls the switches 48 of the current control devices 41, 42 accordingly via the terminals 43A, 43B.

As a result, the comparator 201 and the comparator 301 regulate the voltage U50 to the voltage U25. The current 1201 is output as the control value of the comparator 201, which--within the control range--is largely proportional to the voltage difference and leads to an adjustment of the voltage U50 to the voltage U25. Alternatively, it would also be possible to carry out a comparison between the voltages U50 and U25 at the comparator 201 (or 301) and the resulting differential voltage to process. For driving the optocouplers 49, 149, however, the output of the control value as a current 1201 is advantageous.

The selection device 32 is thus implemented by comparatively simple hardware means. Of course, it is also possible to implement the selection device 32 using a microcontroller. However, this must work quickly and safely, and the hardware solution shown is therefore advantageous.

In practice, in the supply network 10 of the US split phase type and also in other networks, there are asymmetries between the individual phases, for example different amplitudes. This can cause problems with other solutions. A great advantage of the device 20 described in this application is that the voltage at the point 50 can be well regulated even in the presence of unbalances. The device 20 is thus comparatively robust and also functions under poor conditions.

As stated, the device also works in the event that a neutral conductor N is connected to one of the lines 51 or 54 . In this case, however, the corresponding line 51 or 54 can be connected to point 50 without further testing.

The first drive circuit 218 and the second drive circuit 220 enable the current control device 41 to be switched on (cf. 12 ) by a first logic signal, a non-conducting switching of the current control device 41 by a second logic signal and the passage of the input-side signal from the comparator 210 (cf. 13 ) or from point 50 by a third logic signal.

In the same way, the first drive circuit 318 and the second drive circuit 320 enable the current control device 42 to be switched on (cf. 12 ) by a first logic signal, a non-conducting switching of the current control device 42 by a second logic signal and a passage of the input-side signal from the comparator 310 (cf. 13 ) or from point 50 by a third logic signal.

For example, if control device 400 detects a neutral conductor N on line 51, it sends a second logic signal to control circuits 318 and 320 and a first logic signal to control circuits 218 and 220. On the other hand, if control device 400 detects that no neutral conductor is connected is, it sends the third logic signal to all drive circuits 218, 220, 318, 320.

For example, the drive circuit 218 can set the input of the diode 213 to +5 V and the positive input of the comparator 201 to -15 V in order to permanently activate the switch 148 of the current control device 41 at the first logic signal. In contrast to the current control device 41, in the case of the current control device 42 the positive input of the comparator 301 would have to be set to +15 V by the control circuit 320.

A deactivation of the current control device 41 at a second logic signal can by connecting the input of the diode 213 of 13 done with the point 99.

The logical signals from controller 400 may be referred to as controller signals.

14 12 shows an exemplary embodiment of the drive device 166. The drive device 166 is connected on the input side to the direct current power supplies 191 and 192 on the direct current side of the AC/DC converter 190, compare 1 . On the output side, control device 166 is connected to line 46 and line 112 and, as a voltage source, generates a voltage between lines 46 and 112.

The drive device 166 has a galvanic isolating device 330 which electrically isolates a first side 345 of the drive device 166 from a second side 346 . In the exemplary embodiment, the galvanic isolating device 330 is designed as a transformer with a first winding 327 and a second winding 328 . On the first side 345, the DC lines 191 and 192 are connected to a driver module 320, and the driver module 320 enables the voltage on the DC lines 191, 192 to be switched through or blocked to output-side lines 323, 324 of the driver module 320, depending on a signal on a line 322, which signal is specified, for example, as a clocked signal by a control device.

The line 323 is connected to a first terminal of the first winding 327 via a capacitor 325 and the line 324 is connected to the other terminal of the first winding 327 . The second winding 328 is connected to a line 331 on the one hand and to a line 332 on the other hand. Line 331 is connected through a diode 333 to a line 337 and through a diode 334 to a line 338 . Line 332 is connected through a diode 335 to line 337 and through a diode 336 to line 338 .

The cathodes of diodes 333 and 335 are connected to line 337 and the anodes of diodes 334 and 336 are connected to line 338 . A capacitor 339 is provided between the lines 337 and 338 and the line 337 is connected to a line 341 through a resistor 340 . Line 341 is connected to line 338 via a zener diode 343 , the cathode of zener diode 343 being connected to line 341 .

During operation, the driver module 320 switches the voltage on the direct current lines 191, 192 through to the lines 323, 324 in a clocked manner as a function of the signal at connection 322, and as a result a current flows via the first winding 330 to the capacitor 325 and then from the capacitor 325 in the opposite direction. The current that changes over time results in an inductive transmission into the second winding 328, and an AC voltage (or at least a pulsating DC voltage) is produced on the lines 331, 332, which is rectified again by the bridge rectifier with the diodes 333, 334, 335, 336 becomes.

Capacitor 339 smoothes the voltage between lines 337 and 338, and Zener diode 343 limits the voltage at outputs 341 and 338.

The driver module 320 is, for example, of the MCP1416 type from Microchip. The transformer 330 is, for example, of the type PA2001NL from Pulse Electronics Power. The zener diode 343 is, for example, of the type PTV7.5B-M3/84A from Vishay and results in a voltage limitation at approximately 7.5 volts. The control device 166 shown in the exemplary embodiment is made up of a number of components. Alternatively, for example, DC/DC converter ICs with a built-in galvanic isolation device can be used, and the DC lines 191, 192 and the lines 46 and 112 can be connected directly to such ICs. A suitable DC/DC converter IC is the 1 S4E_1207S1 U from GAPTEC-Electronic GmbH & Co. KG. A transformer as a galvanic isolation device 330 facilitates energy transmission. However, other galvanic isolating devices 330 are also possible, for example optocouplers designed for energy transmission or isolating devices with capacitive isolation.

In the first test setups, the energy source for the control device 166 was the voltage on the lines 51 and 54 of 1 been used. The quality of the control of the voltage limiter 45 was not optimal here. Detailed investigations have shown that in a supply network 10 of the US split phase type, in which the active conductors HOT1 and HOT2 simultaneously have a zero crossing of the voltage, reliable switching of the transistors 160 is not guaranteed in the region of these zero crossings. Since the leakage currents to be compensated for by the compensation current generating device 60 are capacitive currents which have a phase shift of 90 degrees to the mains voltage, large compensation currents from the virtual neutral conductor 50 to the protective conductor PE are required, especially when the mains voltage crosses zero, and the transistors 160 should work well around the zero crossings of the mains voltage. By feeding the control device 166 from the direct current lines 191, 192 behind the AC/DC converter 190, high-quality control of the transistor 160 can be ensured. The galvanic separation by the galvanic separation device 330 leads to a secure separation of the AC supply network from the DC network at the DC conductors 191 and 192. This increases the safety of the overall system. If the direct current lines are connected directly or indirectly via a DC/DC converter to the battery 194 1 are connected, as is the case, for example, in electric vehicles or hybrid vehicles, a good power supply or voltage supply via the control device 166 is possible.

A wide range of variations and modifications are of course possible within the scope of the present invention.

Two current control devices 41, 42 are basically sufficient. To increase the maximum possible performance or in the case of unusual supply networks, the other connections 22, 23 can also be used 7 corresponding current control devices are assigned in whole or in part.

The provision of the galvanic isolating device 49 makes it easier to control the individual switches. Other drive circuits are also possible, but they often require more circuitry.

When switching from 12 the main current for the virtual neutral conductor flows directly via switches 148 and 149. Alternatively, an additional common switch can be provided, via which the main current flows and which is controlled via switches 148 and 149. This enables the provision of a high quality common switch.

Operational amplifiers, for example, can be used as comparators 201, 210, 301, 310 the. However, comparators are preferably used, and the faster switching time has had a qualitatively advantageous effect.

The galvanic isolation device 49 can also be provided with a Darlington stage in order to enable a higher maximum current.

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US 2011/0057707 A1 [0002]
• US 2014/0327371 A1 [0003]
• US 2016/0154047 A1 [0004]
• US 2013/0043880 A1 [0005]

Claims (17)

Device (20) for generating a compensation current (62) on a supply network (10), which device (20) has a voltage regulation device (30), a compensation current generating device (60), an AC/DC converter (190), a first point (50 ), has at least two connections (21, 24) and a protective conductor connection (25), which AC/DC converter (190) is connected to the two terminals (21, 24) on the AC side and has a first DC line (191) and a second DC line (192) on the DC side, which voltage regulation device (30 ) is designed to regulate a first voltage (U50) at the first point (50) to a second voltage (U25) at the protective conductor connection (25), at least two current control devices (41, 42) are assigned to which voltage control device (30) for influencing the first voltage (U50) at the first point (50), which current control devices (41, 42) are each connected to an associated terminal (21; 24) and to the first point (50) and are designed to cause a current flow between the enable or disable the first point (50) and the associated connection (21, 24), which current control devices (41, 42) at least partially have a voltage limiter (45), which voltage limiter (45) has a transistor (160) and a drive device (166) for driving the transistor (160), which drive device (166) has a first side ( 345) and a second side (346) which is galvanically isolated from the first side (345) by a first galvanic isolating device (330), which control device (166) on the first side (345) is connected to the first direct current line (191) and the second direct current line (192), which control device (166) is designed to enable energy transmission from the first side (345) to the second side (346) via the first galvanic isolation device (330) and on the second side (346) to generate a control voltage for the voltage limiter (45), and which compensation current generation device (60) is designed to generate a compensation current (62) between the protective conductor connection (25) and the first specified point (50) as a function of a compensation current specification signal (I_COMP_S). device after claim 1 , in which at least two current control devices (41, 42) are assigned to the voltage control device (30) for influencing the voltage (U50) at the first point (50). device after claim 1 or 2 comprising a battery (194), which battery (194) is connected on the DC side of the AC/DC converter (190). Device according to one of the preceding claims, in which at least one of the current control devices (41, 42) has a switch arrangement (47), which switch arrangement (47) comprises a first switch (48), which switch arrangement (47) by the assigned control signal (43A, 43B; 143A; 143B) can be controlled and is designed to enable a current flow between the first point (50) and the associated connection (21; 24) in a first state (Z1), and in a second state (Z2) the To prevent current flow between the first point (50) and the associated terminal (21; 24). device after claim 4 , in which the switch arrangement (47) is designed to influence the magnitude of the current flow in the first state (Z1) as a function of the control deviation (U_DIFF) of the voltage control device (30). device after claim 4 or 5 , in which the voltage regulating device (30) is connected to the switch arrangement (47) via at least one second galvanic isolating device (49), which second galvanic isolating device (49) is preferably designed as an optocoupler or as a transformer. Device according to one of Claims 4 until 6 , wherein the switch arrangement (47) has a second switch (148), which second switch (148) is connected in parallel to the first switch (48). device after claim 7 , in which the voltage regulating device (30) is designed to influence the current flow via the first switch (48) when the phase at the associated connection (21; 24) has a positive half-wave, and the current flow via the second switch (148) to influence when the phase at the associated terminal (21; 24) has a negative half-cycle. Device according to one of Claims 4 until 8th , In which at least one of the current control devices (41, 42) has a bridge rectifier (100), which bridge rectifier (100) has a first bridge rectifier connection (113), a second bridge rectifier connection (114), a first line (111), a second line (112) and the switch arrangement (47), which first bridge rectifier connection (113) is connected to the associated connection (21; 24), which second bridge rectifier connection (114) is connected to the first point (50 ) is connected, which bridge rectifier (100) is designed to - allow a current flow from at least one of the bridge rectifier terminals (113, 114) to the first line (111), but a current flow from the first line (111) to the bridge rectifier terminals (113 , 114), - to allow a current flow from the second line (112) to at least one of the bridge rectifier terminals (113, 114), but to prevent a current flow from the bridge rectifier terminals (113, 114) to the second line (112), - in the first predetermined state (Z1) of the switch arrangement, a current flow between the first bridge rectifier connection (113) and the second bridge rectifiera Connection (114) to allow in at least one direction, and - in the second predetermined state (Z2) of the switch arrangement (47) to prevent a current flow between the two bridge rectifier terminals (113, 114). Device according to one of the preceding claims, in which at least one of the current control devices (41, 42) is adapted to allow a current flow between the first point (50) and the associated terminal (21, 24) in both directions. Device according to one of the preceding claims, in which at least one of the current control devices (41, 42) is connected in parallel with a capacitor (133, 134). Device according to one of the preceding claims, which has at least one voltage measuring device (35, 36), which voltage measuring device (35, 36) is designed to determine a voltage value characterizing the voltage as a function of the voltage at at least one of the terminals (21, 24). detect, and in which the voltage control device (30) is designed to drive the current control devices (41, 42) depending on the measured voltage value. device after claim 12 which is set up to turn on the current control device (41; 42) assigned to this connection (21; 24) when a connected neutral conductor (N) is detected at one of the connections (21; 24) in order to ensure a permanent connection of this connection (21 , 24) with the first point (50). device after claim 12 or 13 , in which the voltage control device (30) has a first voltage regulator (201) and a second voltage regulator (301), and in which the voltage control device (30) depending on the measured voltage value (U21, U24; U21-U24) either controls the first voltage regulator (201 ) or the second voltage regulator (301) activated. Device according to one of Claims 12 until 14 , in which the at least one voltage measuring device (35, 36) comprises a first voltage measuring device (35) and a second voltage measuring device (36), and in which the voltage control device (30) is designed to control the current control devices (41, 42) as a function of the To control the difference between the measured voltage value of the first voltage measuring device (35) and the measured voltage value of the second voltage measuring device (36). Device according to one of the preceding claims, in which the connections (21, 24) have a first connection (21) and a second connection (24), which can be connected to a supply network during operation in such a way that the first connection (21) has a first Phase (HOT1) and at the second terminal (24) a second phase (HOT2) is present, which second phase (HOT2) is 180° out of phase with the first phase. Device according to one of the preceding claims, which has a control device (400), and in which the current control devices (41, 42) at least partially have at least one drive circuit (218, 220; 318, 320), which at least one drive circuit (218, 220; 318, 320) is designed to enable the associated current control device (41, 42) to be switched conductive or non-conductive as a function of a control device signal from the control device (400), in order to thereby connect a neutral conductor to the first point ( 50) to allow.

Images