Absorption circuit arrangement for traction converter of rail vehicle

Abstract

The invention relates to an absorber circuit arrangement for a traction converter of a rail vehicle, comprising a first rectifier on the grid side, a second rectifier on the load side, a DC voltage intermediate circuit connecting the first rectifier and the second rectifier, and an intermediate circuit capacitor arranged in the DC voltage intermediate circuit, the absorber circuit arrangement comprises a switching device comprising switching cells and an inductor, each switching cell comprising two terminals, at least two power semiconductor switches and a switching cell capacitor and being designed to provide at least two different voltages on the terminals depending on the switching position of the power semiconductor switches, the absorber circuit arrangement further comprises at least one capacitive energy store, which is connected in series to the switching device, and a control device, which is designed to control at least the power semiconductor switches of the switching unit. The invention also relates to a rail vehicle and a method for controlling the absorption circuit device.

Description

Technical Field

[0001] The present invention relates to an absorption circuit device for a traction converter of a rail vehicle, wherein the rail vehicle can be designed in particular as a multiple unit or a locomotive for passenger transportation. Background Art

[0002] Especially in Europe, the AC voltage supply network that provides electrical energy for railway vehicles uses a single-phase AC voltage of 15 kV, 16.7 Hz or 25 kV, 50 Hz. Rail vehicles can usually be connected to the overhead line of the power supply network through one or more pantographs. One or more primary windings of the traction transformer are connected to the pantograph, and the single-phase AC voltage of the power supply network is applied to the pantograph. According to the selected voltage transformation ratio, a lower single-phase AC voltage is applied to one or more secondary windings of the traction transformer. The traction converter of the rail vehicle is connected to one or more secondary windings. The traction converter includes one or more grid-side rectifiers, which are usually designed as four-quadrant converters (4QS) and are thus designed to be able to perform feedback transmission. One or more grid-side rectifiers convert the single-phase AC voltage provided by the traction transformer into a DC voltage for the DC voltage intermediate circuit of the traction converter. The intermediate circuit capacitor composed of one or more parallel capacitors is arranged as an energy storage device in the DC voltage intermediate circuit. Also connected to the DC voltage intermediate circuit are one or more load-side rectifiers, which are usually designed as pulse rectifiers (PWR). The load-side rectifiers convert the DC voltage provided by the DC voltage intermediate circuit into an AC voltage with variable level and frequency, via which one or more traction motors are supplied. Also connected to the DC voltage intermediate circuit are further rectifiers for auxiliary operation of the rail vehicle and, if necessary, one or more traction batteries.

[0003] The electrical power provided by the grid-side rectifier has, in addition to a constant component, a superimposed component, the pulse frequency of which is twice the frequency of the power supply grid. In order to be able to provide the load-side power rectifier with a constant power component that is largely free of these pulses, a series resonant circuit consisting of passive components is usually arranged in the DC voltage intermediate circuit of the traction converter and in parallel with the intermediate circuit capacitor as a so-called absorption circuit. Such a series resonant circuit consists, for example, of a series circuit of a capacitor or capacitor with an inductor or a low-ohmic resistance choke. The resonant frequency of the absorption circuit is adjusted to twice the grid frequency, which is 33.4 Hz for the above-mentioned 15 kV, 16.7 Hz grid and 100 Hz for the 25 kV, 50 Hz grid, so that the component in this frequency is almost completely dissipated by the absorption circuit. In addition, the high-frequency component, in particular the other harmonics with the frequency of the grid frequency and the switching frequency of the rectifier, is filtered out in addition with the help of the intermediate circuit capacitor. Such an absorption circuit consisting of passive components has the disadvantage that the components used are heavy, bulky and costly. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide an absorption circuit device for a traction converter of a rail vehicle that eliminates the above-mentioned disadvantages. The technical problem is solved according to the present invention by an absorption circuit device for a traction converter of a rail vehicle, a rail vehicle comprising at least one such absorption circuit device, a method for controlling an absorption circuit device, and an application of the absorption circuit device in a traction converter of a rail vehicle or an application of the method.

[0005] According to the invention, an absorption circuit device for a traction converter of a rail vehicle, wherein the traction converter has at least one first grid-side rectifier, at least one second load-side rectifier, a DC voltage intermediate circuit connected to the at least one first rectifier and the at least one second rectifier and having a first and a second voltage potential, and at least one intermediate circuit capacitor arranged in the DC voltage intermediate circuit, characterized in that the absorption circuit device is arranged in the DC voltage intermediate circuit and connected in parallel with the at least one intermediate circuit capacitor, the absorption circuit device comprises at least one switching device, the switching device comprises at least one switching unit and at least one inductor, wherein each switching unit comprises two terminals, at least two controllable power semiconductor switches and at least one switching unit capacitor, and each switching unit is designed to provide at least two different voltages at the terminals depending on the switching position of the power semiconductor switch, and wherein the at least one inductor is connected in series with the at least one switching unit, the absorption circuit device further comprises at least one capacitive energy storage device, wherein the at least one capacitive energy storage device is connected in series with the at least one switching device, and the absorption circuit device further comprises a control device, wherein the control device is designed to control at least a plurality of power semiconductor switches of the at least one switching unit.

[0006] The significantly smaller inductance of the switching device of the absorption circuit device according to the invention advantageously achieves a reduction in losses, which are caused by chokes in known passive absorption circuits. In addition, the use of smaller and lighter electrical and electronic components can advantageously reduce weight and reduce the required volume compared to known passive absorption circuits. The absorption circuit device also makes it possible to simply adapt the absorption circuit device to the grid frequency of the power supply network, wherein the control device can advantageously additionally dynamically track and adjust the operating frequency of the absorption circuit device when the grid frequency changes. In addition, in particular in so-called multi-system rail vehicles, which can be powered simultaneously using the above-mentioned two grid voltages and grid frequencies, the switching device for adapting the resonant frequency, which is necessary in the case of a passive absorption circuit, is advantageously omitted.

[0007] According to a first improved scheme of the absorption circuit device, the first terminal of each switching unit is optionally connected to the second terminal of other switching units, the first voltage potential of the DC voltage intermediate circuit, at least one inductance of the switching device, or a capacitive energy storage device of the absorption circuit device, and the second terminal of each switching unit is optionally connected to the first terminal of other switching units, the second voltage potential of the DC voltage intermediate circuit, at least one inductance of the switching device, or a capacitive energy storage device of the absorption circuit device.

[0008] According to another improvement scheme of the absorption circuit device, the switching unit includes at least two power semiconductor switches connected into a half bridge, and the half bridge is connected in parallel with at least one switching unit capacitor, and the first terminal of the switching unit is connected to the outer terminal of the half bridge, and the second terminal of the switching unit is connected to the center terminal of the half bridge.

[0009] According to another improved scheme of the absorption circuit device as an alternative to the above-mentioned improved scheme, the switching unit includes at least four power semiconductor switches connected into a full bridge, wherein at least two power semiconductor switches are connected into corresponding half bridges, and the two half bridges and at least one switching unit capacitor are connected in parallel, and the first terminal of the switching unit is connected to the outer terminal of one of the two half bridges, and the second terminal of the switching unit is connected to the center terminal of the other half bridge of the two half bridges.

[0010] According to a further development of the absorption circuit device, at least two switching devices are connected in parallel and these are connected in series with at least one capacitive energy store.

[0011] According to another improvement of the absorption circuit device, the absorption circuit device also includes at least one protection unit, wherein the at least one protection unit is connected in parallel with at least one switching device, and wherein the at least one protection unit is designed to allow an inrush current flowing through the absorption circuit device to bypass the at least one switching device.

[0012] According to another improvement of the absorption circuit device, the absorption circuit device also includes at least one switch, wherein each switch is respectively assigned to at least one switching device, and wherein each switch is designed to disconnect the current path through the assigned switching device, in particular to disconnect the connection to the DC voltage intermediate circuit or the capacitive energy storage device.

[0013] According to the present invention, the rail vehicle includes at least one traction transformer device that can be connected to an AC voltage power supply network via at least one pantograph, and the rail vehicle also includes at least one traction converter, the traction converter includes at least one first rectifier on the grid side, at least one second rectifier on the load side, a DC voltage intermediate circuit connected to at least one first rectifier and at least one second rectifier, and at least one intermediate circuit capacitor arranged in the DC voltage intermediate circuit, and the rail vehicle also includes at least one traction motor connected to the second rectifier, characterized in that an absorption circuit device according to the present invention is arranged in the DC voltage intermediate circuit of each traction converter, and the rail vehicle also includes a control device, which is designed to at least control the power semiconductor switch of the absorption circuit device.

[0014] According to a development of the rail vehicle, the rail vehicle is designed as a multiple unit, in particular for regional and long-distance traffic, or as a locomotive.

[0015] According to a further development of the rail vehicle, at least one first grid-side rectifier is designed as a self-guided pulse rectifier, in particular a four-quadrant converter, and at least one second load-side rectifier is designed as a self-guided pulse rectifier, in particular a pulse inverter.

[0016] The absorption circuit device according to the present invention, which can also be called an active absorption circuit in contrast to known passive absorption circuits, comprises a series circuit consisting of one or more switching units, one or more inductors and one or more capacitive energy storage devices. Other corresponding series circuits can be connected in parallel with the series circuit, wherein these other corresponding series circuits can, for example, use one or more capacitive energy storage devices together. In addition, the absorption circuit device can also have a protection unit, which is used to bypass the surge current from the components of the switching device and / or from the switch for disconnecting the connection of the switching device to the DC voltage intermediate circuit or the capacitive energy storage device, wherein the switching device, especially the faulty switching device, can be disconnected by means of the switch so that the absorption circuit device can continue to operate through the remaining switching devices.

[0017] If a current flows at the connection points of the absorption circuit device and the DC voltage intermediate circuit and a voltage is simultaneously present at these connection points, the absorption circuit device absorbs or releases electrical energy depending on the signs of the current and voltage. A compensated energy balance is achieved in that the at least one capacitive energy store and / or the at least one switching unit capacitor and / or the at least one inductor absorbs and releases the corresponding energy minus the heat losses generated in the components.

[0018] With the aid of a control device, in particular based on measured variables detected by means of sensors, such as a voltage at a capacitor and / or a current in an inductor, the power semiconductor switches of a switching unit or multiple switching units are appropriately controlled to influence the current through the absorption circuit device and thereby its energy consumption and energy output, so that a desired compensation for the energy or power of pulses in the DC voltage intermediate circuit is generated, the energy or power coming from, for example, a single-phase power supply network.

[0019] The switching unit of the absorption circuit device according to the present invention comprises, for example, a half-bridge having at least two power semiconductor switches, wherein the power semiconductor switches are, for example, respectively designed as a combination of an IGBT (insulated gate bipolar transistor) and a diode connected in antiparallel thereto, the IGBT and the diode being respectively made of silicon semiconductor material (Si); or as a MOSFET (metal oxide semiconductor field effect transistor) having a so-called body diode existing internally; or as a combination of a MOSFET and a Schottky diode connected in antiparallel thereto, the MOSFET and the Schottky diode being respectively made of silicon carbide semiconductor material (SiC). Alternative semiconductor materials such as gallium nitride (GaN) or diamond have a larger band gap than silicon like silicon carbide, and the power semiconductor switches and, if necessary, the diodes can be manufactured in the same manner. The reverse withstand voltage strength of known power semiconductor switches is, for example, 1.2 kV, 1.7 kV, 2.3 kV, 3.3 kV, 4.5 kV or 6.5 kV.

[0020] The switching cell capacitance of the corresponding switching cell can be designed, for example, as a capacitor, in particular a film capacitor or an electrolytic capacitor. In order to increase the capacitance, another such capacitor can be connected in parallel with respect to the switching cell capacitance in addition, but other energy storage devices, in particular double-layer capacitors or battery cells can also be connected in parallel in addition or alternatively. The switching cell capacitance is designed with low inductance in this case to achieve rectification of the power semiconductor switches of the switching cell. In particular, when the power semiconductor switches are connected to form a half bridge, the reverse withstand voltage strength of the power semiconductor switches is preferably selected to be higher than the maximum value of the voltage at the switching cell capacitance corresponding to the half bridge plus a voltage reserve for possible transient effects.

[0021] In particular, when the switching unit comprises a half bridge, the power semiconductor switches of the switching unit are controlled alternately by the control device in at least two switch position combinations, so that at least two voltages, for example a zero volt voltage and a current voltage at the switching unit capacitor, are alternately applied to the terminals of the switching unit. The switching frequency of the power semiconductor switches preferably corresponds to a multiple of twice the power supply frequency, for example in the range between 500 Hz and 5 kHz.

[0022] The current at the terminals of the switching unit multiplied by the voltage applied at these terminals results in a power flow flowing into or out of the switching unit. After the power loss, for example, the power loss caused by the parasitic ohmic resistance, is subtracted from the power flow, the energy consumption or energy output of the switching unit capacitor is obtained by observing in time. A voltage change depending on the energy loading state of the switching unit capacitor is generated similarly to the capacitive energy storage device of the absorption loop device. The corresponding purpose of the design of the absorption loop device is that, at each desired operating point, taking into account the voltage applied to the capacitive energy storage device, at least one switching unit capacitor and the DC voltage intermediate loop, at least one switching unit has at least one switching state, in which a voltage with a positive or negative sign can be set at each inductance of at least one inductance. This design realizes that the current in each switching unit or switching device is increased or decreased by appropriate control of the power semiconductor switch, and the current in the absorption loop device is increased or decreased thereby.

[0023] The at least one capacitive energy storage device of the absorption circuit device comprises, for example, one or more capacitors, wherein these capacitors can be designed in particular as film capacitors or electrolyte capacitors corresponding to the switching cell capacitance. Additionally or alternatively, the capacitive energy storage device can again comprise a double-layer capacitor or a battery cell, in particular a lithium-ion-based battery cell, to increase the capacity.

[0024] During operation of the absorption circuit device or the traction converter, in particular when at least one switching unit is designed as a half bridge, the voltage at the capacitive energy store changes in accordance with the above description. The capacitive energy store is preferably designed such that the maximum value of its voltage reached after full energy loading is in the range of several tens of volts or in the range between one and ten percent lower than the intermediate circuit voltage or the voltage of the intermediate circuit capacitor.

[0025] The capacitance of the capacitive energy store is preferably selected such that the difference between the voltage applied to the capacitive energy store and the intermediate circuit voltage is so small that at each point in time there is a switching state for each switching unit in which a positive or negative voltage can be set at each inductance of the associated switching device. The critical point in time is, for example, when the voltage of the capacitive energy store reaches a minimum value, in particular when the energy loading is minimal, since the switching unit must then be able to generate a maximum minimum voltage value.

[0026] A voltage is applied to at least one inductance of a corresponding switching device of the absorption circuit device, which generates a change in the current in the inductance and thus in the current in the absorption circuit device. The voltage at the inductance depends on the switching state of the switching unit, the voltage at the switching unit capacitance and the voltage at the capacitive energy storage device.

[0027] Compared to the inductance or choke of a passive absorption circuit, the inductance of the switching device can be selected to be significantly smaller, for example, five to twenty-five times smaller. In contrast to a passive absorption circuit, during operation of the absorption circuit device, a current is generated through the inductance, which oscillates around a desired fundamental oscillation and a certain harmonic oscillation. The desired fundamental oscillation is here the rated value of the current through the absorption circuit device, usually a sinusoidal current with twice the grid frequency, which compensates the power of the correction pulse. The effective value of the fundamental oscillation of the current through the inductance is preferably not greater than the effective value of the current through the inductance of the passive absorption circuit.

[0028] The slope of the current defines the harmonic oscillations at a certain switching frequency of the power semiconductor switches of the switching unit. The voltage level at the inductor should preferably be reduced at each operating point to achieve a low switching frequency, which has the advantage of low switching losses of the power semiconductor switches and / or to achieve a low inductance, which has the advantage of low costs, less required installation space, less weight, and / or to achieve low harmonic oscillations, which has the advantage of low losses in the inductor. This can be achieved, for example, by connecting a plurality of switching units in series, thereby achieving a more refined grading of the voltage applied to the inductor. In addition, the absorption circuit device can be designed, for example, so that the voltage at the switching unit capacitor is as low as possible, and corresponding to the above description, the voltage at the capacitive energy storage has only a small difference with the intermediate circuit voltage.

[0029] The inductance of the switching device is formed, for example, by a ferromagnetic core having one or more grooves, and the contour of the core having one or more discrete or distributed gaps. The grooves are wound by one or more windings, which are formed by conductive wires, foils or litz wires connected in series or in parallel. If the absorption circuit device includes a plurality of switching devices and therefore a plurality of inductors, these inductors can, for example, share a common core having a plurality of windings.

[0030] For example, when a short-circuit fault occurs in a DC voltage intermediate circuit, a rectifier of a traction converter or other components connected to the DC voltage intermediate circuit, high surge currents are generated, which may flow through the absorption circuit device arranged in the DC voltage intermediate circuit. If the anti-parallel diodes of the power semiconductor switches of the switching unit are designed for normal operation in terms of their surge current resistance and are designed to not switch or disconnect in time, the diodes may be damaged, thereby affecting the operation of the absorption circuit and thus the operation of the traction converter. Therefore, the absorption circuit device preferably includes at least a protection unit, by means of which the surge current is bypassed from the switching unit or its power semiconductor switches and diodes.

[0031] The protection unit preferably comprises one or more diodes and one or more ohmic resistors connected in series therewith. The protection unit is preferably arranged in the absorption circuit device so that the voltage at the protection unit changes only slowly during the normal operation of the absorption circuit device, for example, at multiple, especially double or quadruple times the grid frequency. If, for example, at least one switching unit comprises a corresponding half-bridge, the slow change can be achieved, for example, by not connecting the terminals of the protection unit to the central terminals of each half-bridge. This advantageously enables the use of low-cost grid rectifier diodes with high surge current resistance. If the protection unit is connected in parallel with a switching device or a plurality of switching devices connected in parallel, this preferred arrangement of the protection unit is produced. At least one diode of the protection unit is oriented in the cut-off direction when the absorption circuit device is operating normally, and is oriented in the conduction direction corresponding to the diode to be protected of the power semiconductor switch of the switching device in the event of a fault.

[0032] Compared to the switching device, the at least one resistor of the protection unit has a lower effective resistance value. The resistance value is preferably designed such that a portion of the surge current flowing through the switching device is lower than the permissible value for the diode to be protected, while another larger portion of the surge current flows through the protection unit that can be more heavily loaded. In addition to converting part of the energy of the surge current into heat, the at least one resistor of the protection unit limits the amplitude of the surge current, thereby advantageously enabling a cost-effective design of the at least one diode of the protection unit.

[0033] The control device of the absorption circuit device can, for example, only be assigned to the absorption circuit device or the power semiconductor switch and the switches provided if necessary. However, the control device is preferably a component or a special function of a central control device of the traction converter, which in particular also controls the power semiconductor switches of the first and second rectifiers and, if necessary, other components. The function of the control device is designed, for example, as part of the drive control device of the rail vehicle.

[0034] The method according to the invention for controlling an absorption circuit device according to the invention is characterized in that a plurality of power semiconductor switches of at least one switching unit are controlled by a control device so that at least one harmonic of the network frequency present in the DC voltage intermediate circuit is compensated by the current generated by the absorption circuit device.

[0035] According to an improvement of the method according to the invention, the power semiconductor switches are controlled by the control device so as to track state variables, in particular the voltage at at least one switching cell capacitor of at least one switching cell and the current flowing through at least one inductor of at least one switching device and the voltage at at least one capacitive energy storage device of the absorption circuit device, for preset rated values.

[0036] According to another development of the method according to the invention based on the above development, the control device stops controlling the power semiconductor switch if the intermediate circuit voltage determined by the control device is within a preset threshold value and / or the rated current flowing through at least one inductor is within a preset threshold value.

[0037] The intermediate circuit voltage can be determined by the control unit by suitable measurements. The rated current or the current to be set through the absorption circuit device is preferably within a preset threshold value near the zero point. Stopping the control of the power semiconductor switches of at least one switching unit preferably puts these semiconductor switches in a blocking state.

[0038] According to a further development of the method according to the invention, when at least two switching devices are connected in parallel, the power semiconductor switches are controlled by the control device, in particular with a phase shift, so that harmonic oscillations of the current in the switching devices are at least partially cancelled out.

[0039] The main purpose of controlling the absorption circuit device by the control device is to set a current through the absorption circuit device with the help of which superimposed components, especially those caused by the grid frequency, can be exactly or almost exactly compensated, so that the intermediate circuit voltage can be kept constant. In addition to these components, other high-frequency components, especially other harmonics with a frequency of the grid frequency and / or the switching frequency of the rectifier, can be compensated in addition by suitable control.

[0040] The control is used to influence, in particular, state variables in the absorption circuit arrangement. This influence can, for example, involve voltages at the capacitors of the capacitive energy storage and the switching unit and / or currents through one or more inductors. These voltages and / or currents can be tracked, for example, and in particular independently of one another, to preset setpoint values ​​for regulation. For example, due to capacitor discharges caused by leakage currents or due to energy losses in power semiconductor elements and inductors, deviations from preset setpoint values ​​can occur.

[0041] Suitable setpoint values ​​for the state variables exist, for example, when these setpoint values ​​achieve a constant or, with a permissible deviation of, for example, a few percentage points, an almost constant intermediate circuit voltage. The setpoint values ​​are additionally selected, for example, so that the maximum value of the voltage at the at least one capacitive energy store is only a few tens of volts or one to ten percentage points below the intermediate circuit voltage. On this basis, the setpoint values ​​can also be selected, for example, so that for the setpoint values ​​for the capacitive energy store, the voltage at the at least one switching unit capacitor is still selected to be sufficiently high, or to have an exemplary reserve of a few tens of volts or one to ten percentage points of the DC intermediate circuit voltage, so that at least one switching state of the switching unit is always present, in which a voltage with a positive or negative sign can be set at the at least one inductance of the correspondingly assigned switching device.

[0042] By means of the supplementary selected setpoint values ​​for the voltage at the capacitor of the capacitive energy store and the switching unit capacitor, it can be ensured that, on the one hand, the current through the absorption circuit arrangement can be influenced by means of the control device, and, on the other hand, the voltage present at the at least one inductor can be kept as low as possible. The low voltage at the inductor advantageously leads to a lower current change per unit time, thereby making it possible to have fewer harmonic oscillations in the current through the inductor and correspondingly in the DC voltage intermediate circuit.

[0043] In particular, by means of a time-varying selection of the switching states of power semiconductor switches of switching units of at least one switching device by the control device, a voltage occurring at at least one inductance of the switching device can be set, thereby in turn causing a change in the current through the inductance or through the snubber device.

[0044] For example, if the absorption circuit arrangement comprises a plurality of switching devices connected in parallel, each of which has at least one switching unit and at least one inductance, the current in the corresponding switching device can be influenced by the selection of the switching state so that harmonic oscillations of the current in the total current generated by the plurality of currents are at least partially offset. For this purpose, for example, the power semiconductor switches of the switching units of the corresponding switching devices can be controlled in a time-shifted or phase-shifted manner so that when the current in the inductance of one switching device increases with a certain slope, the total current of the other switching devices decreases with the same or at least a similar slope, or when the current in the inductance of one switching device decreases with a certain slope, the total current of the other switching devices increases with the same or at least a similar slope.

[0045] If there are multiple possible switching states, which respectively apply voltages of the same sign at at least one inductance of the switching device and cause current changes of the same sign in the inductance, the appropriate switching state can be selected in particular according to the following criteria. As a first criterion, the following switching state can be selected from the multiple switching states that respectively affect the voltage at the switching cell capacitors of the switching cells so that these switching cell capacitors are charged, which switching state causes one or more switching cell capacitors to be charged with a voltage that is maximally lower than a preset rated value. Correspondingly, the following switching state can be selected from the multiple switching states that respectively affect the voltage at the switching cell capacitors so that these switching cell capacitors are discharged, which switching state causes one or more switching cell capacitors to be discharged with a voltage that is maximally higher than a preset rated value. As a second criterion, if the desired rated current can be achieved by a low voltage within a certain time period, such as one to three switching cycles, the switching state that causes the application of a low voltage at at least one inductance can be selected to achieve a low slope of the current and thereby achieve low harmonic oscillation, otherwise, the switching state that causes the application of a higher voltage is selected. Furthermore, in particular when the first criterion and the second criterion cannot be satisfied simultaneously, the third criterion may be that if the voltage at the switching unit capacitor deviates from a preset rated value by more than a preset percentage point, for example twenty percentage points, the first criterion is preferred.

[0046] If the set current of the absorption circuit device corresponds to the current to be compensated minus possible harmonic oscillations, which are generated, for example, by switching on and off the power semiconductor switches of the rectifier, then this set current can be regarded as an ideal compensation current. However, limited deviations from this ideal compensation current and therefore from the ideal constant intermediate circuit voltage, for example a few tens of volts or a few percentage points, can bring advantages for the control of the absorption circuit device without having a negative impact on the traction converter or the traction system.

[0047] In particular, in a time period when only a small compensation current is required, the control device can, for example, stop controlling the switching state of the power semiconductor switch. This stop causes the power semiconductor switch to be blocked accordingly, so that no current passes through the corresponding switching device. Preferably, the control is stopped as long as the intermediate circuit voltage is within a preset error range defined by an upper threshold value and a lower threshold value. For example, if the sign of the compensation current changes due to the harmonic oscillation caused by the absorption circuit device itself, and the rated value of the basic oscillation of the current through the absorption circuit device has a constant sign in the same time period, the control is stopped. Only when the voltage is expected to exceed or fall below the preset error range, the control of the power semiconductor switch is reactivated, and the compensation current is set by the absorption circuit until the intermediate circuit voltage reaches the following value, and the intermediate circuit voltage is kept within the error range for as long a time period as possible based on this value. After reaching this value, the control device will stop controlling the power semiconductor switch again. The current passing through the absorption circuit device is thus limited in time, thereby advantageously reducing losses and improving the efficiency of the absorption circuit device.

[0048] As an alternative or supplementary solution to the time period of stopping the control of the power semiconductor switch, the ideal compensation current can be deviated to track and adjust the voltage at the storage unit capacitor and at least one capacitive energy storage device. For at least two switching devices connected in parallel, each of which has at least one switching unit and an inductor connected in series with the switching unit, in addition to the compensation current, other current shares can be generated, for example. These other current shares preferably have a significantly lower frequency than the basic oscillation or a DC share that changes only slowly. If this DC share flows through the first switching device, this causes at least one storage unit capacitor of the switching unit of the first switching device to charge or discharge according to the sign of the current share. If the current for the DC share flows back through the second switching device, the current loop for the DC share is closed in this way, which correspondingly causes at least one switching unit capacitor of the switching unit of the second switching device to discharge or charge accordingly. Thus, the voltage at the switching unit capacitor of the parallel switching device can be affected independently of each other.

[0049] If, however, the DC component flows back through the first switching device and through at least one capacitive energy storage device of the absorption circuit device, thus closing the current loop for the DC component, this leads to a simultaneous charging or discharging of the capacitive energy storage device and at least one switching cell capacitance of a switching cell of the first switching device, depending on their sign. This closing of the current loop is also achieved when the absorption circuit device comprises only a single switching device, instead of the two switching devices connected in parallel as described above.

[0050] Alternatively or additionally, the current through the absorption circuit device can also be controlled as follows, so that in the energy consumption phase of the absorption circuit device, the assumed or preset rated value of the intermediate circuit voltage is lower than the rated value, and in the energy output phase of the absorption circuit device, the assumed or preset rated value of the intermediate circuit voltage is higher than the rated value. The phases of energy absorption and energy output here occur corresponding to the basic oscillation. This leads to a decrease in the energy stored in at least one switching unit capacitor compared to the ideal compensation current when the intermediate circuit voltage always corresponds to the rated value for the intermediate circuit voltage, and thus leads to a decrease in the voltage applied to the switching unit capacitor on average. On the contrary, the current through the absorption circuit device can be controlled so that in the energy output phase, the intermediate circuit voltage is lower than the rated value for the intermediate circuit voltage, and in the energy consumption phase, the intermediate circuit voltage is higher than the rated value, which leads to an increase in the energy stored in at least one switching unit capacitor on average, and thus leads to an increase in the voltage applied to the switching unit capacitor on average. This characteristic can be advantageously used to change the corresponding voltage at at least one switching unit capacitor. This can be achieved, for example, by generating an additional alternating current share, which is phase-shifted by plus or minus ninety degrees relative to the current share exchanged with the DC voltage intermediate circuit. This additionally generated alternating current component produces fluctuations in the intermediate circuit voltage, the phase of which coincides with the phase of the energy consumption or energy output, thereby reducing or increasing the energy stored in at least one switching cell capacitor and thus causing the voltage applied to the switching cell capacitor to decrease.

[0051] By means of the combination of the above-described control of the absorption circuit device by the control device, the voltage at the at least one switching cell capacitor and the voltage at the at least one capacitive energy store can be influenced independently of one another and thus regulated to follow the corresponding desired or predefined setpoint values.

[0052] Without influencing the voltage at the at least one switching cell capacitor, the change in the average voltage at the at least one capacitive energy storage device of the absorption circuit device can be achieved, for example, by generating an additional DC component in the current through the capacitive energy storage device, wherein, in the case of a plurality of switching devices connected in parallel, the additional DC component is applied jointly and preferably evenly distributed. The additional DC component causes the average voltage at the capacitive energy storage device to increase or decrease. In order to avoid a corresponding increase or decrease in the average voltage at the switching cell capacitor, a fluctuation is simultaneously generated in the intermediate circuit voltage, so that the energy consumption or energy output of the switching cell capacitor is compensated by the DC component.

[0053] In order to be able to keep the average voltage at the switching cell capacitor constant, it is necessary to balance the different voltages at the switching cell capacitor, which are caused by manufacturing tolerances of the switching cell capacitor, for example. In this case, fluctuations can be generated in the intermediate circuit voltage for changes in the average voltage at all switching cell capacitors and when the average voltage at at least one capacitive energy storage device does not change, which fluctuations lead to the desired energy consumption or energy output of the switching cell capacitor. In addition, in the case of at least two switching devices connected in parallel, each of which has at least one switching cell capacitor, a DC component of the current can be generated to balance the voltage at the switching cell capacitor between these parallel switching devices, the DC component flows through the first and second switching devices, and thus affects the average voltage in the first switching device in the opposite direction to the average voltage in the second switching device. In addition, in a switching device having a plurality of switching cells connected in series, the switching state of the switching cell can also be additionally selected according to the direction of the current to balance the different voltages at the switching cell capacitors of these switching cells, the switching state respectively increases the too low voltage at the switching cell capacitor or at least makes the voltage no longer further reduced, or makes the voltage no longer further increased. In the case of a corresponding design of the absorption circuit device, the method can preferably be carried out simultaneously or in parallel.

[0054] The control device preferably controls the absorption circuit device by taking into account values ​​determined by means of suitable sensors, in particular values ​​of the current flowing in the absorption circuit device and the voltage applied to the capacitor. These values ​​are determined, for example, at ten to one thousand times the grid frequency. The control device determines the actual state of the absorption circuit device based on these values ​​and, based on this actual state, derives the measures required to approach the desired target state of the absorption circuit device by suitable control of the power semiconductor switches.

[0055] According to the above method, the voltage at at least one capacitive energy storage device and at least one switching unit capacitor can only be adjusted by the control device with limited dynamics to track the determined or preset rated values. If during normal operation of the absorption circuit device, for example due to a sudden change in the load in the traction system, the rated values ​​also change suddenly, then due to the limited dynamics, it may no longer be possible to approach these rated values ​​with the help of the above control method for the power semiconductor switch, so that the absorption circuit device is in the following operating state, in which at least in a part of the period of the basic oscillation, there is no switching state of the power semiconductor that enables the setting of a voltage of two signs at each inductance of the absorption circuit device. This makes it impossible to arbitrarily control the current through the corresponding inductance. This situation can be regarded as a violation of the operating range that can be actively controlled.

[0056] In order to identify whether such a violation of the actively controllable operating range must be taken into account in the following cycle based on the determined actual state of the absorption circuit device, the required compensation current and taking into account the characteristics of the absorption circuit device, and to be able to derive appropriate measures thereupon, the control device should preferably regularly predict the future behavior based on these parameters, for example, in a time period corresponding to half of the cycle of the network frequency. The duration of such a prediction of the state variables, for example, the voltage state at the capacitor storage device and the switching unit capacitor, is checked to determine whether the actively controllable operating range may be violated. The cause of the violation is, for example, the absence of a preset switching state of the switching device, which should be used to increase or reduce the current in the correspondingly assigned inductance. Preferably, the prediction can be limited to particularly critical time points within the considered cycle, for example, the time points at which the stored energy in the absorption circuit device is maximum and / or minimum. If it can be determined that the maximum or minimum voltage associated with at least one switching unit capacitor and the capacitor storage device does not violate the actively controllable operating range, then it is expected that this situation will not occur at other time points.

[0057] In order to counteract a violation of the actively controllable operating range, if such a violation has already occurred or is predicted by the control device, according to a first method, for example, the power semiconductor switch of at least one switching unit can be kept in a switching state corresponding to the blocking state for a certain period of time at the beginning of the phase in which the absorption circuit device is to absorb or release energy, and then set to the following switching state in which the semiconductor power switch sets the compensation current until the end of the phase. The blocking time period is preferably designed in this case so that in the following time period, until the end of the energy absorption or energy output phase, a violation of the actively controllable operating range cannot be predicted or occurs. In cooperation with the rectifier of the traction converter, the control according to the first method generates a variable intermediate circuit voltage, which changes the actual state of the absorption circuit device over time, so that the absorption circuit device can be converted into normal operation without violating the actively controllable operating range.

[0058] Furthermore, in order to counteract a violation of the actively controllable operating range, if such a violation has already occurred or is predicted by the control device, according to a second method, the power semiconductor switch of at least one switching unit can be set at the beginning of a phase in which the absorption circuit device is to absorb or release energy, in a switching state in which the power semiconductor switch sets a compensation current, until the compensation current can no longer be set due to a violation of the actively controllable operating range. After this time period, the power semiconductor switch is set to a switching state corresponding to blocking or continuous conduction until the end of the phase. In cooperation with the rectifier of the traction converter, the control according to this second method still produces a variable intermediate circuit voltage, which changes its actual state over time, so that the absorption circuit device can be transferred to normal operation without violating the actively controllable operating range.

[0059] In order to select one of the two methods mentioned above in order to change from an actual or predicted violation of the actively controllable operating range to normal operation of the absorption circuit device, the control device can calculate the following scenario based on the actual state of the absorption circuit device, in which the capacitive energy storage device and the switching unit capacitor of the absorption circuit device are charged or discharged with pure direct current until the actively controllable operating range is violated for the first time, wherein the direct current is evenly distributed to the parallel switching devices. If, for example, such a violation consists in the occurrence of an excessively high voltage at at least one capacitive energy storage device, in particular a voltage higher than the intermediate circuit voltage, the first method is preferably carried out, while for other violations, the second method is preferably carried out.

[0060] According to the invention, the absorption circuit arrangement according to the invention is used in a traction converter of a rail vehicle or for the method according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The present invention is described below based on embodiments. In the accompanying drawings:

[0062] Figure 1 shows a rail vehicle with a traction system operating on an AC power supply network,

[0063] Figure 2 A traction system with an absorption circuit arrangement according to the invention is shown,

[0064] Figures 3A-3C An alternative design of the absorption circuit device according to the present invention is shown.

[0065] Figures 4A-4E An alternative design of the switching device of the absorption circuit device according to the present invention is shown.

[0066] Figures 5A-5CAn alternative design of the switching device of the absorption circuit device according to the present invention is shown.

[0067] Figure 6 An absorption circuit device according to the present invention having a plurality of switch devices, each of which has two switch units, a switch and a protection unit, is shown to explain the function of the absorption circuit device, and

[0068] Figure 7 A further absorption circuit arrangement according to the invention is shown, which has a plurality of switching devices, each of which has a switching unit.

[0069] For the sake of clarity, identical or identically or virtually identically acting components are provided with the same reference symbols. DETAILED DESCRIPTION

[0070] Figure 1 A rail vehicle TZ is schematically shown in a side view. The rail vehicle TZ is designed as a multiple-carriage train, of which only the end car bodies EW and the middle car body MW connected thereto are shown. The two car bodies have corresponding carriages, which are supported on rails (not shown) by bogies in the form of kinetic bogies TDG in which traction motors TM are arranged and by mobile bogies LDG. As an alternative to a multiple-carriage train, the rail vehicle can also be designed as a locomotive with only one carriage.

[0071] In addition to the traction motors TM in one or more kinetic bogies TDG, the traction system TS of the rail vehicle TZ also includes a traction converter TUR, a control device ST for controlling at least the traction converter TUR, a transformer TF and a pantograph PAN. These components of the traction system TS are schematically shown as being arranged in or at the end car EW. In practice, however, especially when the end car body is also used for passenger transport, these components are usually arranged in special areas, bottom areas, top areas within the car body, or distributed in multiple car bodies of the rail vehicle TZ. This makes it possible to provide corresponding passenger compartments in the car body, wherein the passenger compartments of adjacent car bodies can be connected by car body aisles as shown. In addition, other components of the traction system TS, such as one or more traction batteries, as well as auxiliary systems for component operation and passenger comfort can be provided in a supplementary manner and arranged accordingly. However Figure 1 These components are not shown in detail.

[0072] The traction system TS can be electrically connected to an overhead line (not shown) of the power supply network via a pantograph PAN arranged in the roof area of ​​the carriage of the end car body EW. For example, a single-phase AC voltage of 15 kV, 16.7 Hz or 25 kV, 50 Hz, which is common in Europe, is applied to the overhead line. This AC voltage is input to the primary winding of the transformer TF, and the transformer reduces the voltage level on the grid side to a lower voltage level according to the selected voltage transformation ratio of the transformer TF. One or more secondary windings of the transformer TF are connected to one or more grid-side first rectifiers NSR of the traction converter TUR, and the first rectifiers are designed as four-quadrant converters, for example. The first rectifiers NSR respectively convert the single-phase AC voltage of the transformer TF into a DC voltage, which is input to a common DC voltage intermediate circuit ZK. In addition, one or more load-side second rectifiers LSR of the traction converter TUR are connected to the DC voltage intermediate circuit ZK, and the second rectifiers are designed as pulse inverters, for example. The second rectifier LSR converts the DC voltage of the DC voltage intermediate circuit ZK into a three-phase AC voltage with variable frequency and amplitude, via which the stator windings of one or more traction motors TM are respectively supplied. The respective functions of the rectifiers NSR and LSR are controlled by a central control device ST of the traction system TS or traction converter TUR.

[0073] Figure 2 A more detailed schematic diagram shows Figure 1The traction system TS in the rail vehicle TZ is shown in FIG. The primary winding of the transformer TF is connected to the pantograph PAN on the one hand and to the guide rails on the other hand, for example, via a wheel set. The three secondary windings of the transformer TF, which are shown as an example, are respectively connected to a first rectifier NSR on the grid side of the traction converter TUR, which converts the AC voltage provided by the secondary windings into a DC voltage, via which a common DC voltage intermediate circuit ZK is supplied with power. Two second rectifiers LSR on the load side, which are shown as an example, are supplied with power by the intermediate DC voltage circuit ZK, which convert the DC voltage provided by the DC voltage intermediate circuit ZK into three-phase AC voltages with variable level and frequency, via which a traction motor TM in a kinetic bogie TDG of an end car body EW of a rail vehicle TZ is supplied with power, for example. In particular, when the traction motor TM is designed as a three-phase synchronous motor, each second rectifier LSR supplies power to only one traction motor TM, while when the traction motor TM is designed as a three-phase asynchronous motor, each second rectifier LSR can also supply power to multiple traction motors TM in parallel, for example, to supply power to corresponding kinetic bogies. The central control device ST of the traction converter TUR or the traction system TS controls the corresponding functions of the first and second rectifiers NSR, LSR, in particular the switch positions of the corresponding power semiconductor switches of the first and second rectifiers, by means of control signals generated by the control device ST. The control device ST performs control here, for example, based on information from different sensors SEN, in particular voltage and current sensors. Figure 1 and Figure 2 The signaling connections between control device ST and rectifiers NSR, LSR and sensor SEN are each indicated by a dashed line.

[0074] An intermediate circuit capacitor CZK is arranged in the DC voltage intermediate circuit ZK of the traction converter TUR. The intermediate circuit capacitor CZK, shown as a single capacitor by way of example, can include one or more capacitors connected in parallel, wherein these capacitors can also be arranged distributedly, for example, as corresponding components of the second rectifier LSR. During normal operation of the traction converter TUR, an intermediate circuit voltage UZK is present at the intermediate circuit capacitor CZK or between the first voltage potential UP1 and the second voltage potential UP2 of the DC voltage intermediate circuit ZK.

[0075] Furthermore, a snubber circuit arrangement SKA according to the invention is arranged in parallel with the intermediate circuit capacitor CZK in the DC voltage intermediate circuit ZK, which is likewise connected in terms of signaling to the control device ST, which is again indicated by means of a dashed line.

[0076] FIG. 3 shows an exemplary alternative design of an absorption circuit device SKA according to the present invention, which has a Figure 2It is correspondingly arranged in the DC voltage intermediate circuit ZK and connected in parallel with the intermediate circuit capacitor CZK. Figure 3A The absorption circuit device SKA of the absorption circuit device SKA comprises a switching device SA and a capacitive energy storage device CES connected in series with the switching device. The switching device SA is connected to a first voltage potential UP1 of the DC voltage intermediate circuit ZK, while the capacitive energy storage device CES is connected to a second voltage potential UP2 of the DC voltage intermediate circuit ZK. The arrangement of the two components SA, CES of the absorption circuit device SKA and their connection to the voltage potentials UP1, UP2 of the DC voltage intermediate circuit ZK are selected here as examples.

[0077] and Figure 3B The alternative absorption circuit arrangement SKA in FIG. 1 comprises two switching devices SA1 , SA2 connected in parallel and a common capacitive energy store CES connected in series therewith. Figure 3C Another alternative absorption circuit device SKA includes a plurality of switching devices SA1 to SAn connected in parallel and a common capacitive energy storage device CES connected in series with the switching devices. Figure 3B and Figure 3C The parallel connection of a corresponding plurality of switching devices SA enables scaling of the performance of the absorption circuit arrangement SKA, wherein the switching devices SA or their switching units SE can be controlled by the control device ST, for example, in a time-shifted or phase-shifted manner. Figure 3C The absorption circuit device SKA further includes a protection unit PR which is connected in parallel with the switching devices SA1 to SAn. Figure 3A and 3B The absorption circuit device SKA preferably also includes such a protection unit PR.

[0078] FIG. 4 shows an exemplary alternative embodiment of a switching device SA of an absorption circuit arrangement SKA according to the invention. Figure 4A and 4B The alternative switching devices SA here each include a switching unit SE, each of which has a first terminal AS1, a second terminal AS2 and an inductor DR connected in series with the switching unit SE. Figure 4A and Figure 4B As shown, the series inductor DR can alternatively be connected as Figure 4A is connected to the first terminal AS1 of the switching unit SE as shown or as Figure 4B As shown, it is connected to the second terminal AS2.

[0079] and Figure 4C , 4D The alternative designs of the switching devices SA of 4C and 4C each comprise two switching units SE connected in series, wherein the inductance DR can alternatively be connected as a result of the series connection. Figure 4CAs shown, it is connected to the second terminal AS2 of the second or lower switching unit SE in the figure, or as shown Figure 4D As shown, the first or upper switching unit SE is connected to the second terminal AS2 and the first terminal AS1 of the second or lower switching unit SE, or as shown Figure 4E As shown, it is connected to a first terminal AS1 of the first or upper switching unit SE.

[0080] It is also possible for a corresponding switching device SA to have more than two switching units SE connected in series and / or more than one inductance.

[0081] FIG. 5 shows an exemplary alternative embodiment of a switching unit SE of a switching device SA of an absorption circuit arrangement SKA according to the invention. Figure 5A The switching unit SE comprises a half bridge with two power semiconductor switches LSIP and LSIN, each of which is designed as an IGBT made of silicon semiconductor material. The power semiconductor switches LSIP and LSIN have a nominal reverse withstand voltage strength of, for example, 1.2 kV, 1.7 kV, 2.3 kV, 3.3 kV, 4.5 kV or 6.5 kV, depending in particular on the intermediate circuit voltage UZK and the number of switching units SE connected in series of the switching device SA. The switching position of the power semiconductor switches LSIP and LSIN is controlled by a control device ST, the switching frequency of which corresponds to a multiple of the frequency of the double power supply network. Depending on the corresponding switch position, a voltage of zero volt or a voltage corresponding to the voltage at the switching unit capacitor SEC of the switching unit SE can be applied to the terminals AS1 and AS2 of the switching unit SE. The first terminal AS1 of the switching unit SE is connected here to the outer terminal of the half bridge or the upper power semiconductor switch LSIP, while the second terminal AS2 of the switching unit SE is connected to the central terminal of the half bridge.

[0082] Each power semiconductor switch LSIP, LSIN is provided with an anti-parallel switching diode DP, DN or an idle diode. The switching unit capacitor SEC connected in parallel with the half bridge can be designed as a film or electrolyte capacitor, for example. In order to increase the capacitance of the switching unit capacitor SEC, for example, multiple such capacitors can be connected in parallel or alternatively double-layer capacitors or battery cells can be connected in parallel.

[0083] Figure 5BThe alternative design of the switching device SE includes a total of four power semiconductor switches connected to form a full bridge, wherein at least two power semiconductor switches are connected to form a corresponding half bridge, and the two half bridges and at least one switching unit capacitor are connected in parallel. An anti-parallel switching diode or free-wheeling diode is still correspondingly provided for each power semiconductor switch. The first terminal AS1 of the switching unit SE is connected to the center terminal on the left side of the two half bridges, and the second terminal AS2 of the switching unit SE is connected to the center terminal on the right side of the two half bridges.

[0084] Figure 5C Alternative designs of the switching device SE still include Figure 5A The corresponding half-bridges differ, however, in that the power semiconductor switches LSMP, LSMN are each designed as MOSFETs made of silicon carbide semiconductor material. The antiparallel diodes may also be inherently contained in the corresponding MOSFETs, but may alternatively also be implemented as separate components.

[0085] Figure 6 An absorption circuit device SKA according to the invention is shown in a DC voltage intermediate circuit ZK. The absorption circuit device SKA comprises n switching devices SAq connected in parallel, where q=1, 2, ..., n, and a capacitive energy store CES connected in series with the switching devices, wherein the capacitive energy store CES can, in accordance with the above description, in particular comprise a plurality of capacitors connected in parallel. Each switching device SAq comprises two switching cells SEpq connected in series, where p=A or B, and an inductance DRq connected in series with the respective switching cell SEpq. The switching cell SEpq is connected in this case to a Figure 5A Correspondingly, a corresponding half-bridge is included, which has two power semiconductor switches LSIPpq and LSINpq, each designed as an IGBT, and a free-wheeling diode DPpq connected in anti-parallel with the power semiconductor switch. In addition, the switch unit SEpq includes a switch unit capacitor SECpq connected in parallel with the half-bridge. When the intermediate circuit voltage UZK is in a range of typically between 1.2 kV and 2.2 kV, the power semiconductor switches LSIPpq and LSINpq have a reverse withstand voltage strength of, for example, 1.2 kV or 1.7 kV, and the switch unit capacitor SECpq has a withstand voltage strength in the range of 700 V to 1.2 kV.

[0086] also, Figure 6The absorption circuit device SKA includes switches TRq connected in series with corresponding switching devices SAq. These switches TRq can be designed as corresponding power switches or isolating switches, for example, and enable the corresponding switching devices SAq to be separated from the DC voltage intermediate circuit ZK. As a result, the operation of the absorption circuit device SKA can continue through other switching devices SA2 to SAn when a component of the first switching device SA1 fails, for example. In addition, the absorption circuit device SKA also includes a protection unit PR connected in parallel with the switching device SAq to bypass the free-wheeling diodes DPpq and DNpq of the switching unit SEpq, for example, due to a short circuit of the DC voltage intermediate circuit ZK or due to a voltage breakdown of the DC voltage intermediate circuit and the discharge of the intermediate circuit capacitor caused thereby. The protection unit PR includes, for example, a series circuit consisting of a grid diode and a resistor, and the ohmic resistance of the resistor is 2 to 200 milliohms.

[0087] according to Figure 6 , assuming that the first voltage potential UP1 of the DC voltage intermediate circuit ZK is positive and the second voltage potential UP2 is negative. If the current IDRq through the inductor DRq flows from the direction of the positive first voltage potential UP1 of the DC voltage intermediate circuit ZK to the direction of the negative second voltage potential UP2, the current is positive. Similarly, if the voltage UDRq at the inductor DRq is oriented from the positive first voltage potential UP1 to the negative second voltage potential UP2, the voltage is positive, and if the voltage USECpq at the switched capacitor SEpq is oriented from the first terminal AS1 to the second terminal AS2 at the switching unit SEpq, the voltage is positive.

[0088] Table A below shows the power of the four power semiconductor switches LSIPpq, LSINpq of the two switching units SEAq, SEBq of the switching device SAq. Figure 6 The control device ST (not shown) controls the switching states, and the corresponding states for the respective combinations of the switching states. In this case, the switching state 1 represents conduction, and the switching state 0 represents blocking.

[0089] Table A

[0090]

[0091] If the power semiconductor switches LSIPpq and LSINpq of the switch unit SEpq are not turned on, and a positive current IDRq not equal to zero flows through the inductor DRq, the diode DNpq is turned on, which has the same effect as turning on the power semiconductor switch LSINpq. If a negative current IDRq not equal to zero flows through the inductor DRq, the diode DPpq is turned on accordingly, which has the same effect as turning on the power semiconductor switch LSIPpq.

[0092] Table B shows the voltage UDRq generated by the selected state at the inductance DRq of the switching device SAq and the corresponding effect on the voltages USECAq, USECBq at the switching device capacitances SECAq, SECBq of the two switching devices SEAq, SEBq depending on the direction of the current IDRq through the inductance DRq.

[0093] Table B

[0094]

[0095] If the voltages USECAq, USECBq at the switching cell capacitances SECAq, SECBq of the two switching cells SEAq, SEBq of the switching device SAq are considered to be identical or differ only by a few volts or a few percentage points, the voltages can be identified as USECCq. In order to obtain a state in which the voltages USECAq, USECBq at the switching cell capacitances SECAq, SECBq are equal, switching back and forth between the states Z1q and Z2pq or between Z3q and Z2pq is performed at the selected switching frequency. The state Z2pq is obtained here in accordance with the following table C. According to the table, the state is selected so that the voltages USECAq and USECBq at the switching cell capacitances are similar.

[0096] Table C

[0097]

[0098] Table D below shows which states or switching state combinations are selected in order to set a positive or negative voltage UDRq at the inductance DRq of the switching device SAq.

[0099] Table D

[0100]

[0101] For the second condition in Table D, UCES+(2*USECCq)>UZK>UCES, the switching state causes the current IDRq through the inductance DRq to increase or decrease. By appropriately selecting the duty cycle of the switching state by the control device, the course of the current IDRq can be influenced according to the desired setpoint value.

[0102] Figure 7 An alternative absorption circuit arrangement SKA according to the invention in a DC voltage intermediate circuit ZK is shown. The absorption circuit arrangement SKA again comprises n parallel-connected switching devices SAq (q=1, 2, . . . , n) and a capacitive energy storage device CES connected in series with the switching devices. Figure 6Different from the absorption circuit device SKA of FIG. 1 , each switching device SAq includes only one switching unit SEq and an inductor DRq connected in series with the corresponding switching unit SEq. The switching unit SEq is connected to Figure 5C Correspondingly, a corresponding half-bridge is included, which has two power semiconductor switches LSIPq and LSINq respectively designed as MOSFETs and free-wheeling diodes DPq and DNq connected in reverse parallel with the power semiconductor switches. The free-wheeling diode can be designed as a component inherently contained in the MOSFET and / or as an independent component. In addition, the switch unit SEq includes a switch unit capacitor SECq connected in parallel with the half-bridge. When the intermediate circuit voltage UZK is in a range of usually between 1.2 kV and 2.2 kV, the power semiconductor switches LSMPq and LSMNq have a reverse withstand voltage strength in the range of, for example, 1.2 kV to 3.3 kV, and the switch unit capacitor SECq has a withstand voltage strength in the range of 700 V to 1.6 kV.

[0103] and Figure 6 The absorption circuit device corresponds to the ground, Figure 7 The absorption circuit device SKA includes switches TRq connected in series with corresponding switching devices SAq. These switches TRq can be designed as corresponding power switches or isolating switches, for example, and enable the corresponding switching devices SAq to be separated from the DC voltage intermediate circuit ZK. As a result, the operation of the absorption circuit device SKA can continue through other switching devices SA2 to SAn when, for example, a component of the first switching device SA1 fails. In addition, the absorption circuit device SKA still includes a protection unit PR connected in parallel with the switching device SAq to bypass the free-wheeling diode DPq of the switching unit SEpq, for example, due to a short circuit in the DC voltage intermediate circuit ZK. The protection unit PR includes, for example, a series circuit consisting of a grid diode and a resistor, and the ohmic resistance of the resistor is 2 to 200 milliohms.

[0104] The control device ST controls the power semiconductor switches LSMPq and LSMNq of the switching device SEq in the same manner as described above. Figure 6 Since each switching device SAq has only one switching cell SEq, it is not necessary to balance the voltages at the switching cell capacitances of the switching devices as shown in Table C above.

[0105] Table E below shows the switching states of the two power semiconductor switches LSMPq, LSMNq of the switching unit SEq of the switching device SAq, which are controlled by the control device ST, and the corresponding states for the respective combinations of the switching states. Switching state 1 here means conducting, while switching state 0 means blocking.

[0106] Table E

[0107]

[0108] Table F shows the voltage UDRq generated by the selected states at the inductance DRq of the switching device SAq and the corresponding effect on the voltage USECq at the switching device capacitance SECq of the switching unit SEq depending on the direction of the current IDRq through the inductance DRq.

[0109] Table F

[0110]

[0111] If the power semiconductor switches LSMPq and LSMNq of the switch unit SEq are not turned on, and a positive current IDRq not equal to zero flows through the inductor DRq, the diode DNq is turned on, which has the same effect as turning on the power semiconductor switch LSMNq. If a negative current IDRq not equal to zero flows through the inductor DRq, the diode DPq is turned on accordingly, which has the same effect as turning on the power semiconductor switch LSMPq.

[0112] Finally, the following table G shows which states or switching state combinations are selected in order to set a positive or negative voltage UDRq at the inductance DRq of the switching device SAq.

[0113] Table G

[0114]

[0115] For the second condition of Table G, UCES+USECq)>UZK>UCES, the switching state causes the current IDRq through the inductance DRq to increase or decrease. By appropriately selecting the duty cycle of the switching state by the control device, the course of the current IDRq can be influenced according to the desired setpoint value.

[0116] Apart from Figure 6 and Figure 7 In addition to the absorption circuit device SKA described in the invention, other designs of the absorption circuit device according to the invention can also be considered. These designs can in particular only include a single switching device SA, which has one or more switching units SE connected in parallel. The anti-inrush current protection of the diode of the switching unit can also be realized by means other than the described protection unit PR, for example, by a unit connected in series with the switching unit, when the current or the integral of the current exceeds a preset threshold value within a preset time period, the unit interrupts the current flowing through the switching unit and / or bypasses the switching unit or certain elements of these switching units through one or more current paths with lower impedance.

[0117] Reference numerals list

[0118] AS1, AS2 Switching unit terminals

[0119] CES Capacitor Energy Storage

[0120] CZK Intermediate circuit capacitor

[0121] DP, DN diodes, free-wheeling diodes

[0122] DR Inductor

[0123] EW end body

[0124] EW end body

[0125] FR Direction of travel

[0126] IDRq Current through the inductor

[0127] LDG Mobile Bogie

[0128] LSIP, LSIN, LSMP, LSMN, LSIPpq, LSINpq, LSMPq, LSMNq Power semiconductor switches

[0132] Second rectifier on the load side of the LSR

[0133] MW mid-body

[0134] NSR First rectifier on the grid side

[0135] PAN Pantograph

[0136] PR Protection Unit

[0137] SA, SAq switchgear

[0138] SE, SEq, SEpq switching units

[0139] SEC, SECq, SECpq Switching unit capacitance

[0140] SEN Sensor

[0141] SKA absorption circuit device

[0142] ST Controls

[0143] TDG Kinetic Bogie

[0144] TF traction transformer unit, traction transformer

[0145] TM Traction Motors

[0146] TR1-TRn Switches

[0147] TS Traction System

[0148] TUR traction converter

[0149] TZ rail vehicle

[0150] UCES Voltage at the capacitive energy storage

[0151] UDRq Voltage at the inductor

[0152] UP1, UP2 First or second voltage potential

[0153] USECq, USECpq Voltage at the switching cell capacitor

[0154] UZK Intermediate circuit voltage

[0155] ZK DC voltage intermediate circuit

Claims

1. An absorption circuit device (SKA) for a traction converter (TUR) of a railway vehicle (TZ), wherein: The traction converter (TUR) comprises at least one first grid-side rectifier (NSR), at least one second load-side rectifier (LSR), a DC voltage intermediate circuit (ZK) with a first and a second voltage potential (UP1, UP2) connected to the at least one first rectifier (NSR) and the at least one second rectifier (LSR), and at least one intermediate circuit capacitor (CZK) arranged in the DC voltage intermediate circuit (ZK), Characterized in that the absorption circuit device (SKA) is arranged in the DC voltage intermediate circuit (ZK) and connected in parallel with at least one intermediate circuit capacitor (CZK), and the absorption circuit device comprises: - at least one switching device (SA), comprising at least one switching cell (SE) and at least one inductor (DR), wherein each switching cell (SE) comprises two terminals (AS1, AS2), at least two controllable power semiconductor switches (LSIP, LSIN, LSMP, LSMN) and at least one switching cell capacitor (SEC), and each switching cell is designed to provide at least two different voltages at the terminals (AS1, AS2) depending on the switch position of the power semiconductor switches (LSIP, LSIN, LSMP, LSMN), and wherein the at least one inductor (DR) is connected in series with the at least one switching cell (SE), at least one capacitive energy store (CES), wherein the at least one capacitive energy store (CES) is connected in series with the at least one switching device (SA), and A control device (ST), wherein the control device (ST) is designed to control at least a plurality of power semiconductor switches (LSIP, LSIN, LSMP, LSMN) of the at least one switching unit (SE).

2. The absorption circuit device (SKA) according to claim 1, characterized in that - a first terminal (AS1) of each switching unit (SE) is optionally connected to a second terminal (AS2) of another switching unit (SE), to a first voltage potential (UP1) of a DC voltage intermediate circuit (ZK), to at least one inductance (DR) of a switching device (SA) or to a capacitive energy storage device (CES) of an absorption circuit device (SKA), and - The second terminal (AS2) of each switching unit (SE) is optionally connected to the first terminal (AS1) of the other switching units (SE), the second voltage potential (UP2) of the DC voltage intermediate circuit (ZK), at least one inductance (DR) of the switching device (SA) or a capacitive energy storage device (CES) of the absorption circuit device (SKA).

3. The absorption circuit device (SKA) according to claim 1 or 2, characterized in that: The switching unit (SE) comprises at least two power semiconductor switches (LSIP, LSIN, LSMP, LSMN) connected to form a half bridge, and the half bridge is connected in parallel with at least one switching unit capacitor (SEC), and A first terminal (AS1) of the switching unit (SE) is connected to an outer terminal of the half bridge, and a second terminal (AS2) of the switching unit (SE) is connected to a central terminal of the half bridge.

4. The absorption circuit device (SKA) according to claim 1 or 2, characterized in that: The switching unit (SE) comprises at least four power semiconductor switches connected to form a full bridge, wherein at least two power semiconductor switches are connected to form a respective half bridge, and the two half bridges and at least one switching unit capacitor are connected in parallel, and The first terminal (AS1) of the switching unit (SE) is connected to an outer terminal of one of the two half-bridges, and the second terminal (AS2) of the switching unit (SE) is connected to a central terminal of the other of the two half-bridges.

5. Absorption circuit arrangement (SKA) according to one of the preceding claims, characterized in that At least two switching devices (SA) are connected in parallel and the switching devices (SA) are connected in series with at least one capacitive energy store (CES).

6. Absorption circuit arrangement (SKA) according to one of the preceding claims, characterized in that The absorption loop device (SKA) further comprises: At least one protection unit (PR), wherein the at least one protection unit (PR) is connected in parallel with at least one switching device (SA), and wherein the at least one protection unit (PR) is designed to divert a surge current flowing through the absorption circuit device (SKA) away from the at least one switching device.

7. Absorption circuit arrangement (SKA) according to one of the preceding claims, characterized in that The absorption loop device (SKA) further comprises: At least one switch (TR1, TR2, TRn), wherein each switch (TR1, TR2, TRn) is respectively assigned to at least one switching device (SA1, SA2, SAn), and wherein each switch (TR1, TR2, TRn) is designed to disconnect a current path through the assigned switching device (SA1, SA2, SAn), in particular to disconnect a connection to a DC voltage intermediate circuit (ZK) or a capacitive energy storage device (CES).

8. A rail vehicle (TZ), comprising - at least one traction transformer device (TF) connectable to an alternating voltage supply network via at least one pantograph (PAN), at least one traction converter (TUR), comprising at least one first grid-side rectifier (NSR), at least one second load-side rectifier (LSR), a DC voltage intermediate circuit (ZK) connected to the at least one first rectifier (NSR) and the at least one second rectifier (LSR), and at least one intermediate circuit capacitor (CZK) arranged in the DC voltage intermediate circuit (ZK), and - at least one traction motor (TM) connected to a second rectifier (LSR), It is characterized in that - an absorption circuit arrangement (SKA) according to one of claims 1 to 7 is arranged in the DC voltage intermediate circuit (ZK) of each traction converter (TUR), and The rail vehicle (TZ) further comprises a control device (ST) which is designed to control at least the power semiconductor switches (LSIP, LSIN, LSMP, LSMN) of the absorption circuit arrangement (SKA).

9. The rail vehicle (TZ) according to claim 8, characterized in that The rail vehicle (TZ) is designed as a multiple unit, in particular for regional and long-distance traffic, or as a locomotive.

10. The rail vehicle (TZ) according to claim 8 or 9, characterized in that At least one first grid-side rectifier (NSR) is designed as a self-steering pulse-controlled rectifier, in particular a four-quadrant converter, and at least one second load-side rectifier (LSR) is designed as a self-steering pulse-controlled rectifier, in particular a pulse-controlled inverter.

11. A method for controlling an absorption loop apparatus (SKA), wherein: The absorption circuit device (SKA) is designed according to one of claims 1 to 7, characterized in that a plurality of power semiconductor switches (LSIP, LSIN, LSMP, LSMN) of at least one switching unit (SE) are controlled by a control device (ST) so that at least one harmonic of the grid frequency present in the DC voltage intermediate circuit (ZK) is compensated by the current generated by the absorption circuit device (SKA).

12. The method according to claim 11, characterized in that The power semiconductor switches (LSIP, LSIN, LSMP, LSMN) are controlled by the control device (ST) so as to track state variables, in particular the voltage at at least one switching unit capacitor (SEC) and the current (IDRq) flowing through at least one inductor (DR) of at least one switching device (SA) and the voltage at at least one capacitive energy storage device (CES) of an absorption circuit device (SKA) for preset rated values.

13. The method according to claim 12, characterized in that If the expected intermediate circuit voltage (UZK) determined by the control device (ST) is within a preset threshold value and / or the rated current flowing through at least one inductance (DR) is within a preset threshold value, the control device (ST) stops the control of the power semiconductor switches (LSIP, LSIN, LSMP, LSMN).

14. The method according to any one of claims 11 to 13, characterized in that When at least two switching devices (SA) are connected in parallel, the power semiconductor switches (LSIP, LSIN, LSMP, LSMN) are controlled by the control device (ST), in particular phase-shifted, so that harmonic oscillations of the current in the switching devices (SA) are at least partially cancelled out.

15. Use of an absorption circuit arrangement (SKA) according to one of claims 1 to 7 in a traction converter (TUR) of a railway vehicle (TZ) or use of a method according to one of claims 11 to 14.

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