Device, control device and method for switching a switching element

Abstract

Device with: a switch arrangement with a switching element (121) configured to switch off an electrical current path of a commutation circuit, wherein the commutation circuit has a freewheeling element (142) with a parallel-acting capacitance; a control device (18) configured to control the switching element (121) for switching off and performing a switching operation; wherein the control device (18) is configured to control the switching element (121) for the switching operation with a channel switch-off time duration (t off )to switch, which is shorter than one period (t res ) a resonant oscillation of the commutation circuit to excite an oscillation in the commutation circuit; wherein the control device (18) is configured for an operating state in which the switching operation is based on a switching-off current (I) to be switched off T0,n) is executed if, within a tolerance range, the following conditions are met: IT 0, n = VDC ( C eff 1 + C eff 2 ) 3 C eff 1 C eff 2 L pn π where I TO,n the switching current to be switched off through the switching element (121), V DC a DC link voltage of the commutation circuit, C eff1 an effective capacitance of the commutation resonant circuit associated with the switching element (121), C eff2 an effective capacitance of the commutation resonant circuit associated with the freewheeling element (142), L p an effective electrical inductance of the commutation resonant circuit and n describes a natural number; where at least one of the conditions is met: n = 2i + 1, i ∈ ℕ ; C eff 1 ≠ C eff 2 for ¨ rn = 2 i + 1, i ∈ ℕ 0 .

Description

[0001] The present invention relates to a device with a switch arrangement comprising a switching element, to a control device, and to methods for switching a switching element. The present invention particularly relates to an extended zero-overvoltage switching range.

[0002] In power electronics, there are countless topologies and circuits that switch a current path on and off using a transistor or semiconductor switch. The current path to be switched consists of an electrical conductor and a conductor loop, which, due to the laws of nature, always forms a parasitic inductance. This inductance, typically in the range of 1 nH to 100 nH, prevents the switching process from occurring at any speed. With increasingly faster switching processes in the range of 1 ns to 1000 ns (depending on the power class), high turn-off overvoltages arise at the switching element, especially during turn-off.

[0003] EP 3 512 085 A1 describes a concept for switching a semiconductor switch with low overvoltages.

[0004] Deng, J. [et al.] refers to the challenges of turn-off oscillations in power circuits in “Turn-off overvoltage characterization and mitigation in wide bandgap power transistors” in: 23rd European Conference on Power Electronics and Applications (EPE'21 ECCE Europe), Ghent, Belgium, 2021 , pp. 1-8 001: 10.23919 / EPE21 ECCEEurope50061 .2021 .9570646.

[0005] Matlok, S. explains in "Zero Overvoltage Switching "ZOS" - Breaking the rules of parasitic inductance", Fraunhofer Society for the Promotion of Applied Research eV, January 16, 2018, the zero overvoltage switching - ZOS process for switching off currents.

[0006] Based on this, it would be desirable to enable loss-free or low-loss switching under other, additional conditions.

[0007] The object of the present invention is therefore to create a concept which, starting from the prior art, makes it possible to switch off the switching element with low losses under further, additional conditions.

[0008] This problem is solved by the subject matter of the independent patent claims.

[0009] A core idea of ​​the present invention is to have recognized that a favorable cut-off current, which enables low-loss cut-off, can be determined depending on an intermediate circuit voltage and effective capacitances and inductances of the commutation resonant circuit, and that several valid values ​​are available for this purpose, which further enable the setting of a power of, for example, a DC-DC converter by appropriately selecting the appropriate value, or, conversely, the determination of a corresponding cut-off current depending on a required power of a DC-DC converter or the like.

[0010] According to one embodiment, a device comprises a switch arrangement with a switching element configured to switch off an electrical current path of a commutation circuit, wherein the commutation circuit has a freewheeling element with a parallel-acting capacitance. The device comprises a control device configured to control the switching element for switching off and for executing a switching operation. The control device is configured to switch the switching element for the switching operation with a channel switch-off time duration that is shorter than a period duration of a resonant oscillation of the commutation circuit in order to excite an oscillation in the commutation circuit. The control device is configured for an operating state in which the switching operation is carried out based on a switch-off current to be switched off, if it is satisfied within a tolerance range that ITO,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π where I TO,n the breaking current to be switched off by the switching element, V DC an intermediate circuit voltage of the commutation circuit, C eff1 an effective, i.e. connected and / or parasitic capacitance of the commutation resonant circuit associated with the switching element, C eff2 an effective capacitance of the commutation resonant circuit assigned to the freewheeling element, L p an effective electrical inductance of the commutation circuit and n describes a natural number; where at least one of the conditions is met: n=2i+1,i∈ℕ; Ceff≠Ceff2 for=2i+1,i∈ℕ0.

[0011] The parameter n can be used to adjust the properties of a particular circuit, for example, by varying the magnitude of the breaking current or power. Conversely, the breaking current can be adjusted based on the device's requirements by selecting the appropriate parameter. Alternatively or additionally, taking different effective capacitances into account allows for precise adaptation to the actual circuit.

[0012] According to one embodiment, a control device is designed to switch a switching element to execute a switch-off operation. For this purpose, the control device is designed to determine, based on a property of the switching element, that a switch-off current flowing through the switching element satisfies, within a tolerance range, the condition that ITO,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π where ITO,n the breaking current, V DC an intermediate circuit voltage of a commutation circuit comprising the semiconductor switch, C eff1 an effective capacitance of the commutation resonant circuit assigned to the switching element, C eff2 an effective capacitance associated with a freewheeling element connected to the switching element in the commutation circuit, L p an effective electrical inductance of the commutation circuit and n is a natural number; and at least one of the conditions is met: n=2i+1,i∈ℕ; Ceff1≠Ceff2 for=2i+1,i∈ℕ0 and to switch the switching element based on the result. to obtain a result and to control the switching element based on the result.

[0013] According to one embodiment, a method for controlling a device with a switch arrangement having a switching element configured to switch off an electrical current path of the commutation circuit, wherein the commutation circuit has a freewheeling element with a parallel-acting capacitance, comprises the following steps: controlling the switching element for switching off and for executing a switching operation. Here, for the switching operation, the switching element is switched with a channel switch-off time duration that is shorter than a period duration of a resonant oscillation of the commutation circuit in order to excite an oscillation in the commutation circuit, and the switching operation is executed based on the switch-off current to be switched off if it is satisfied within a tolerance range that IT0,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π where I TO,n the breaking current to be switched off by the switching element, V DCan intermediate circuit voltage of the commutation circuit, C eff1 an effective capacitance of the commutation resonant circuit assigned to the switching element, C eff2 an effective capacitance of the commutation resonant circuit assigned to the freewheeling element, L p an effective electrical inductance of the commutation circuit and n is a natural number; and so that at least one of the conditions is met: n=2i+1,i∈ℕ; Ceff1≠Ceff2 for=2i+1,i∈ℕ0.

[0014] According to one embodiment, a method for controlling a switching element to perform a switch-off operation comprises determining, based on a property of the switching element and obtaining a result, that a switch-off current flowing through the switching element satisfies, within a tolerance range, the condition that IT0,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π where I TO,nthe breaking current, V DC an intermediate circuit voltage of a commutation circuit comprising the semiconductor switch, C eff1 an effective capacitance of the commutation resonant circuit assigned to the switching element, C eff2 an effective capacitance associated with a freewheeling element connected to the switching element in the commutation circuit, L p an effective electrical inductance of the commutation circuit and n is a natural number; and at least one of the conditions is met: n=2i+1,i∈ℕ; Ceff1≠Ceff2 for=2i+1,i∈ℕ0.

[0015] Further advantageous embodiments are the subject of dependent patent claims.

[0016] Advantageous embodiments of the present invention are explained below with reference to the accompanying drawings. Fig. 1 is a schematic block diagram of a device according to an embodiment; Fig. 2 a schematic block diagram of the topology of the device from Fig. 1 highlighting the active participants of a resonance circuit; Fig. 3 schematic diagrams for discussing additional switching currents in accordance with embodiments of the present invention compared to known measures; Fig. 4a-c exemplary representations of voltages across an exemplary semiconductor switch of the device from Fig. 1 in accordance with embodiments of the present invention; Fig. 5 is a schematic representation of two curves of parameters of a device according to embodiments of the present invention; and Fig. 6a-b exemplary temporal relationships of different parameters of embodiments described herein.

[0017] Before exemplary embodiments of the present invention are explained in more detail below with reference to the drawings, it is pointed out that identical, functionally equivalent or equivalent elements, objects and / or structures in the different figures are provided with the same reference numerals, so that the description of these elements shown in different exemplary embodiments is interchangeable or can be applied to one another.

[0018] The embodiments described below are described in conjunction with numerous details. However, embodiments may also be implemented without these detailed features. Furthermore, for clarity, embodiments are described using block diagrams instead of detailed illustrations. Furthermore, details and / or features of individual embodiments may be readily combined with one another, unless explicitly described otherwise.

[0019] The following exemplary embodiments relate to the switching, in particular the switching off, of a switching element. Some of the exemplary embodiments refer in particular to the use of a semiconductor switch as a switching element, although the exemplary embodiments are not limited thereto. Alternatively or in addition to a semiconductor switch, other switching elements can also be arranged that are configured to switch between a conducting and a blocking state, such as relays or MEMS relays, transistors, for example based on carbon nanotubes (CNT) materials and / or diamond materials. Transistors can also be manufactured as MOSFET transistors or bipolar transistors and / or using a manufacturing technology other than MOS.

[0020] One possible application area for such a switching element is a DC-DC converter, where current paths can also be switched off using switching elements in other environments, for example to operate or deactivate loads.

[0021] DC-DC converters can be configured to convert DC voltage with a first electrical voltage level or potential to a second electrical voltage level or potential, where the second level can be higher or lower than the first level. DC-DC converters can include a semiconductor switch that is switched by a control device.

[0022] The following exemplary embodiments relate to switching operations in semiconductor switches. Within the scope of the exemplary embodiments described herein, these are linked to commutation operations in commutation circuits, for example, in connection with DC-DC converters. This means that the commutation operation can be triggered by the switching operation. Therefore, within the scope of some of the exemplary embodiments described herein, it can be synonymously stated that a switching operation excites an excitation resonant circuit of the commutation circuit, and that a commutation operation triggered by the switching operation excites the excitation resonant circuit of the commutation circuit.

[0023] Fig. Figure 1 shows a schematic block diagram of a device 10 according to an embodiment. The device 10 comprises a switch arrangement 12 with at least one semiconductor switch 121. Fig. Figure 1 shows an exemplary half-bridge topology of a DC-DC converter, in which two semiconductor switches 121 and 122 are arranged for illustrative purposes only. These are exemplary formed as MOSFET transistors and may have intrinsic body diodes 141 and 142, respectively, designated D1 and D2. However, it should be noted that, as an alternative to a body diode, a discrete freewheeling element can be connected or coupled in both MOSFET transistors and other implementations. Furthermore, Figure 1 shows Fig. 1 for the semiconductor switches 121 and 122 effective capacitances C eff1 or C eff2 , which may, for example, include, but are not limited to, parasitic capacitances of transistors 121 and 122. For example, additional capacitances may also be arranged, for example by providing discrete components, to adjust the effective capacitance.

[0024] Although the Fig. While Figure 1 shows a half-bridge topology with two semiconductor switches 121 and 122, other topologies can have fewer than two semiconductor switches, i.e., one semiconductor switch, or more than two semiconductor switches, for example, three, four, or more. In principle, the topology can deviate from a half-bridge topology in any way.

[0025] The semiconductor switch 121 is configured to switch off an electrical current path of a commutation circuit. The commutation circuit comprises a freewheeling element, such as diode 142, and a capacitor C acting in parallel with the freewheeling element. eff2 or 162. The freewheeling element can be associated with the semiconductor switch 122 or be a discrete component. To another state of the circuit of the Fig. 1, the roles of the semiconductor switches 121 and 122 can be reversed and, for example, the semiconductor switch 122 can be switched, which leads to a corresponding complementary change in the mathematical relationship described above.

[0026] A control device 18 of the device 10 is configured to control the semiconductor switch 121 and / or the semiconductor switch 122. For this purpose, the control device 18 can provide control signals 221 and 222, respectively, which are coupled directly or indirectly, for example, with the interposition of a driver or an amplifier, to control inputs 241 and 242, respectively, which are configured to receive a corresponding input signal 22'1 and 22'2, respectively, which can be based on or correspond to the control signals 221 and 222, respectively.

[0027] As will be explained in more detail below, the control device 18 is designed to switch the semiconductor switch 121 for the switching operation with a channel turn-off time that is shorter than a period of a resonant oscillation of the commutation circuit. This makes it possible to excite an oscillation in the commutation circuit. The control device 18 is configured for an operating state in which the switching operation of the switch 121 is carried out based on a turn-off current to be turned off. For the turn-off current, it is satisfied within a tolerance range that ITO,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π

[0028] I describes TO,n the switching-off current to be switched off by the semiconductor switch 121, V DC the intermediate circuit voltage of the commutation circuit, C eff1an effective, i.e., interconnected and / or parasitic capacitance of the commutation resonant circuit associated with the semiconductor switch 121, C eff2 an effective capacitance of the commutation resonant circuit assigned to the freewheeling element and L p an effective electrical inductance of the commutation circuit. n is a natural number. At least one of the conditions that n = 2i + 1, i ∈ ℕ is fulfilled. Alternatively or additionally, it is fulfilled that C eff1 ≠ C eff2 for n = 2i + 1, i ∈ ℕ0. In other words, the parameter n is a natural odd number > 1 and / or the two capacities differ.

[0029] Each of the two conditions a) n > 1 on the one hand and b) C eff1 ≠ C eff2 on the other hand, they can be implemented independently and offer corresponding advantages.

[0030] For increasing values ​​of the parameter n, it can be obtained that the breaking current at the increasing commutation time associated with increasing values ​​of n ZOS,n decreases. This can result in decreasing output power when used in a DC-DC converter, for example.

[0031] Furthermore, the Fig. 1 a switching arrangement possibly occurring in practice with an intermediate circuit capacitance C DC and a phase inductance L ph A switching cell comprises, for example, the switching element 121 and 122 and the respective freewheeling element 141 or 142, as well as an effective commutation inductance Lp, which may each comprise parasitic and / or discrete inductances. Furthermore, the switching cell may comprise a parallel capacitance C acting on the switching elements 121, 122 and freewheeling elements 141, 142. eff1 (161) and C eff2 (162). The voltage v mpdenotes the voltage drop across the switched switching element 121. The Fig. 1 shown voltages v mp and v T2 refer to the voltages dropping across the switching elements 121 and 122, respectively, of which v mp in connection with the Fig. 7b will be discussed in more detail.

[0032] The voltages V DC and V LS in conjunction with the switch control lead to a changing current flow in the phase inductance L ph . In the switch-off process, the respective switching element, here the semiconductor switch 121, is required to supply a current I TO,n (Turn-Off), the switching-off current, which corresponds to the instantaneous current flow through L phcorresponds to. Switching off changes the current path from the switching element to the freewheeling element. This change can be referred to as a commutation process. The exemplary embodiments described herein describe an advantageous method and corresponding devices for implementing this commutation.

[0033] Fig. Figure 2 shows a schematic block diagram of the topology of the device 10, highlighting the active components of the resonant circuit. Fig. 2 is valid, for example, for a state after switching off the channel of the transistor T1, but during the commutation period t ZOS,n . The phase inductance L ph can be replaced by a current source 26. The resonant circuit or commutation circuit receives the parasitic inductance L p , the freewheel element 142 and the capacities 161 and 162 or C eff1 and C eff2 with one.

[0034] In other words, the resonant circuit, which includes the parasitic elements, is excited by a certain cut-off current, which will be discussed below. Fig. 1 and Fig. 2 a half-bridge topology is used, however, the described ZOS (Zero Overvoltage Switching, overvoltage-free or overvoltage-avoiding switching) according to the embodiments described herein can be used for a variety of hard-switching topologies.

[0035] The resonant circuit includes, for example, the parasitic capacitances C eff1 and C eff2 of the two power semiconductors T1 and T2 as well as the parasitic inductance L p While in EP 3 512 085 A1 the resonant circuit is excited such that commutation is completed after half a period of the resonant frequency, the embodiments described herein allow different settings of the switch-off process.

[0036] The well-known concept achieves a cut-off current for n=1. The following formula shows the relationship between the period of the resonant circuit and the time in which commutation can be completed: tZOS,n=12n tres where t res the period of the resonance oscillation and t ZOS,n describes the commutation duration or the time in which the commutation can be completed.

[0037] However, based on the known concept, if the resonant circuit is excited with a low current, i.e. a lower breaking current is present during switching, it is possible that the commutation time is extended.

[0038] The inventive concept makes it possible to calculate the required breaking current compared to known concepts for other breaking currents. Unlike the known concept, this not only considers identical values ​​of the effective capacitances, but also designs in which these values ​​differ. Fig. 2 is a Fig. 1 shows an at least partially equivalent circuit comprising a minimum number of required components. The breaking current I TO,n is modeled by an ideal current source 26. The diode D2, 142 terminates the commutation.

[0039] Coming back to the Fig. 1, the control device 18 can be designed to control the switching current through the switching element, i.e. the current I TO,nto adjust or control. The control device 18 can be configured to determine the shutdown current based on at least one of reading a database entry, a calculation, an analog circuit, or an approximation. An analog circuit can, for example, comprise one or more transistors, operational amplifiers, and / or other components capable of mapping the above-mentioned dependency for the shutdown current. This means that the control device can directly or indirectly obtain knowledge of the existing shutdown current in order to determine when the correct or at least approximate current for the shutdown process is present.

[0040] The control device 18 can be designed to control the cut-off current by selecting a value corresponding to the cut-off current I TO,n assigned switching time, in particular a switching time within a clock period.

[0041] According to one embodiment, the control device 18 can be configured to adjust the turn-off current through the semiconductor switch 121 based on a reference current. This can be done, for example, by a so-called peak current mode control, from which the control device 18 can detect that a correct value of the turn-off current is present.

[0042] According to one embodiment, the control device 18 can be configured to evaluate the switching operation for the occurrence of a circuit-induced overvoltage at the semiconductor switch in order to obtain an evaluation result. The evaluation result can indicate a deviation of the switching parameter from a parameter target value, and the control device 18 can be configured to adjust the shutdown current through the semiconductor switch for a future switching operation in order to reduce the circuit-induced overvoltage. This means that the control device 18 can monitor the intended switching results and / or overvoltages. The control device 18 can then adjust the shutdown current to compensate for control errors that may occur, for example, due to deviations, such as when read database entries or other estimated values ​​or reference values ​​are not met due to real conditions.This makes it possible to avoid adverse effects in the circuit.

[0043] One way to enable the control device to adapt operation can be achieved alternatively or by designing the control device to control the semiconductor switch 121 based on a reference current value, meaning that when the reference current value is reached, the switching operation is triggered. Alternatively or additionally, a pulse width can be adjusted, wherein the pulse width can be associated with an associated turn-off current, for example, a larger pulse width is associated with a higher current. Alternatively or additionally, the control device can switch the semiconductor switch based on a time specification for a switching time.

[0044] A further, particularly advantageous embodiment of the control device can be achieved based on the knowledge that additional low-overvoltage states exist in the circuit under which the shutdown processes can be triggered. Thus, one of a plurality of predefined output powers can be called up by an appropriately aligned circuit, such as a DC-DC converter or another type of converter. By selecting the shutdown current, the required output power can be called up and, for example, for several or even all of the adjustable required powers, a good, ideal, or even optimal shutdown current can be determined or stored in a data memory accessible to the control device 18. This means that a corresponding shutdown current can be determined by the control device or can be communicated to the control device, or a combination thereof.

[0045] In a further advantageous embodiment of such a concept, it is also possible for the required average output power or the average target output power to deviate from the predefined reference values. In such a case, in which the required target output power, for example, moves between two predefined output powers, the control device can be configured to control operation of the device based on a combination of different predefined values ​​of the cut-off current in order to at least approximate the target output power. A combination can, for example, be a temporal alternation between different operating modes, i.e., cut-off currents, and / or can relate to the determination of a mixed value.This means that if the device is placed in a situation where a power level is required from the device for which the control device does not know a cut-off current according to the invention, it can derive the applicable cut-off current from the cut-off current values ​​of other power levels, for example, by alternating them over time or by combining them. Alternatively or additionally, the control device can also be designed to calculate or determine the respective optimal cut-off current and adjust it accordingly.

[0046] Alternatively or additionally, the device can be controlled by the control device using a predefined cut-off current, wherein the control device can be configured to select the predefined cut-off current for output powers deviating from predefined average target output powers that exhibits the smallest deviation between the obtained predefined output power and the average required target output power. This can at least limit the negative effects caused by possible overvoltages.

[0047] According to one embodiment, the control device is designed to provide the average target output power, which deviates from the different predefined output powers, based on a temporal alternation between different predefined values ​​of the cut-off current, for example cut-off currents that are each associated with predefined output powers, based on valley skipping and / or based on a burst mode. Burst mode can be advantageous when a low or very low load range exists, as it opens up the possibility of only sporadically transferring load at all. This can, for example, enable operation of a converter down to 0% of the load. Valley skipping can, for example, be implemented such that the converter varies the power by shifting the switch-on time, thereby creating periods without effective power transfer.This enables power control by a factor of, for example, approximately 2.

[0048] If, for example, the control device is configured to provide the average target output power that deviates from the various predefined average output powers, the device can be controlled in a mixed operating state to dynamically switch, for example, jump back and forth, between at least a first predefined value of the cut-off current and a second predefined value of the cut-off current. This makes it possible to obtain the average target output power, averaged over time, from the different values ​​of the individual output powers obtained by the predefined values ​​of the cut-off currents.The control device can be configured to adapt a clock period of the shutdown process associated with a predefined value of the shutdown current of a predefined average output power in order to obtain a shutdown current that differs from the predefined value of the shutdown current and / or to change a target value for the shutdown current compared to a predefined value of the shutdown current in order to change an average output current for the output power while accepting increasing overvoltages. Each of these steps—the dynamic change, the adaptation of the clock period, and / or the adaptation of a target value for the shutdown current—can enable an adaptation of the operating state and / or enable additional operating states compared to predefined operating states.

[0049] The control device can be configured to adjust the advantageous cut-off current in order to obtain intermediate circuit voltage information, which can be achieved, for example, through prior knowledge from measurements and / or other information presentations. The intermediate circuit voltage information can be an intermediate circuit voltage of the commutation circuit, the voltage V DC , for example, coded or as an immediate value. The control device can be configured to determine the cut-off current based on the intermediate circuit voltage information. The intermediate circuit voltage can, for example, be variable or adjusted due to different operating states of the device and / or the switch arrangement and lead to changes in the cut-off current, which is taken into account by the control device.

[0050] According to one exemplary embodiment, the control device can be coupled to a data memory in which at least one associated cut-off current information item is stored for a plurality of intermediate circuit voltage information items. The control device 18 can be configured to read the cut-off current information associated with the intermediate circuit voltage information and to set the cut-off current for the switching operation based on the cut-off current information. This means that the control device can read information from the data memory that indicates the level of the cut-off current to be set.For a specific value or value range of the intermediate circuit voltage information, at least one value for the cut-off current information may be present, wherein this information may, for example, relate to the current itself, a time point, or other associated information from which the control device 18 can derive and adjust the corresponding current according to the present invention.

[0051] The control device 18 can thus be coupled to the data memory, in which at least one associated cut-off current information item is stored for a plurality of values ​​of an operating parameter, such as the intermediate circuit voltage information and / or currents, voltages, or the like in the device, which indicates a target value for the cut-off current. The control device 18 can be configured to control or adjust the current through the semiconductor switch based on the target value.

[0052] According to an advantageous embodiment, however, it is provided that not only one value of the shutdown current information is stored, but rather, depending on the implementation in the data memory, multiple shutdown current information items are stored depending on at least one further operating parameter and / or a dependency of the shutdown current information with respect to the at least second operating parameter. Operating parameters can be understood, for example, as different temperatures of the device or various other parameters that can influence the operation of the device, for example, time information that indicates aging or other changes in the operating state.The control device can be designed to read the cut-off current information associated with the operating parameter (for example intermediate circuit voltage information) from the data memory based on the first operating parameter and the at least second operating parameter and to determine the target value for the cut-off current therefrom.

[0053] According to one embodiment, the control device can measure the required information in whole or in part, estimate it in whole or in part, or receive it in some other way, for example via data signals. The control device can, for example, be configured to receive measured value information associated with a value of an operating state, i.e., directly or indirectly indicating it, and can be configured to calculate a target value for the shutdown current based on the measured value information. Thus, the control device can directly derive the shutdown current to be applied or set based on the measured value information.

[0054] According to one embodiment, the commutation resonant circuit described in connection with embodiments discussed herein may comprise a discrete inductive or discrete capacitive component connected to act combinatorially with a parasitic capacitance value or a parasitic inductance value of the commutation resonant circuit and to influence the resonant oscillation.

[0055] Although a gate series resistor can be used to control or switch a semiconductor switch of a switch arrangement described herein, this is not required, which is why the use of a discrete resistance element can be omitted. The control device can be designed or configured to perform the switching operation with a channel turn-off time as described below. The performance of the driver should be designed such that the driver is capable of setting the channel turn-off time to a value lower than the resonant frequency t res . Advantageous with a time of maximum 1 / 2 t res , especially preferred 1 / 4 t res The shorter the channel turn-off time, the lower the resulting overvoltage can be. The switching time is the time period during which the current in the active region of the semiconductor switch is 90% of the turn-off current ITO,n drops to 10% of the breaking current.

[0056] According to one embodiment, the semiconductor switch 121 is designed to operate in a hard-switching mode during normal operation. Alternatively or additionally, the control device is configured to hard-switch the semiconductor switch 121. Hard shutdown means that the shutdown occurs simultaneously at high current and high voltage.

[0057] According to one embodiment, the commutation resonant circuit is part of a commutation cell of a power electronic energy converter, such as a DC-DC converter, a charger, such as an on-board charger, and / or a brushless DC motor, BLDC motor, and / or in a lighting application such as an LED driver. This enables the advantageous application of the principle described herein in such a DC-DC converter.

[0058] According to one embodiment, a device described herein, such as device 10, is configured as a DC-DC converter comprising one of a boost converter, a buck converter, a half-bridge converter, a full-bridge converter, an inverting converter, and a flyback converter. This enables the application of the described advantageous concept in different configurations of a DC-DC converter, although other implementations beyond a DC-DC converter are also possible.

[0059] Regardless of the use of the control device 18 in the device 10, the control device 18 can be preconfigured such that it is designed to switch a semiconductor switch to carry out a switch-off process, for example the semiconductor switch 121 during a later connection. The control device 18 can be designed to determine, based on a property of the semiconductor switch, that a switch-off current flowing through the semiconductor switch within a tolerance range satisfies the condition that IT0,n=VDC(Ceff1+Ceff2)Ceff1Ceff2Lpn π where I TO,n the breaking current, V DC an intermediate circuit voltage of a commutation circuit comprising the semiconductor switch, C eff1 an effective capacitance of the commutation resonant circuit associated with the semiconductor switch 121, C eff2an effective capacitance, L, associated with a freewheeling element 142 connected to the semiconductor switch 121 in the commutation circuit p an effective electrical inductance of the commutation circuit and n is a natural number; and at least one of the conditions is met: n=2i+1,i∈ℕ; Ceff1≠Ceff2 for=2i+1,i∈ℕ0 and to switch the semiconductor switch (121) based on the result.

[0060] This can be understood as meaning that the control device has knowledge of the cut-off current to be set and sets the cut-off current accordingly and / or selects the times of cut-off accordingly.

[0061] The control device can be configured to determine the property of the semiconductor switch itself, for example by measuring, approximating, or estimating, and / or storing corresponding values, for example in a data storage device. The control device can have an interface configured to receive the corresponding information from a data storage device and / or a sensor.

[0062] The control device can be configured to control the semiconductor switch based on a reference current value, for example, such that a switching operation occurs when the reference current value is reached. Alternatively or additionally, the control device can be implemented to set a pulse width. For this purpose, a topology and the respective components used can be taken into account. By varying the pulse width, a current value can be impressed by an inductance over a wide range or almost arbitrarily. Alternatively or additionally, the control device can use a time specification for a switching instant in order to switch the semiconductor switch based on this.

[0063] In connection with the function for determining the optimal switching currents in the device 10 and / or the control device 18, the optimal switching currents can be determined according to the specified formula depending on the voltage, the parasitic inductance, and the parasitic capacitances, optionally supplemented by discrete components. The switching currents can thus be determined, for example, by calculating the corresponding formula or by reading from a table or by independently determining the optimal currents. If the optimal switching currents are known, the control device or control device can optionally adjust the switching current to control the transistor or semiconductor switch. This can be done by controlling the transistor to be switched off.The control device can achieve the optimum current, for example, by specifying a reference value, specifying a suitable pulse width, and / or specifying a suitable switching time. Another optional function is power control. This can be used for applications requiring different power levels that may not result in the average current of the circuit resulting from the cut-off current. To regulate the desired power, the control device can select the most suitable cut-off current according to the relationship disclosed here. Alternatively or additionally, the control device can choose between two or more cut-off currents I. T0,n alternate to obtain or approximate the desired current on average.

[0064] A method, for example, for controlling the device 10, may thus comprise controlling the semiconductor switch for switching off and for executing a switching operation. The method is carried out such that, for the switching operation, the semiconductor switch is switched with a channel switch-off time that is shorter than a period of a resonant oscillation of the commutation circuit in order to excite an oscillation in the commutation circuit. The switching operation is carried out based on the switch-off current to be switched off, by ensuring, within a tolerance range, that IT0,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π where I TO,n the switching-off current to be switched off by the semiconductor switch (121), V DC an intermediate circuit voltage of the commutation circuit, C eff1 an effective capacitance of the commutation resonant circuit associated with the semiconductor switch (121), C eff2an effective capacitance of the commutation resonant circuit associated with the freewheel element (142), L p an effective electrical inductance of the commutation circuit and n is a natural number; and so that at least one of the conditions is met: n=2i+1,i∈ℕ; Ceff1≠Ceff2 for=2i+1,i∈ℕ0.

[0065] Corresponding to the method for controlling the device, a method for controlling a semiconductor switch to carry out a switch-off process, for example with the aid of a control device described herein, may comprise determining, based on a property of the semiconductor switch and obtaining a result, that a switch-off current flowing through the semiconductor switch fulfills or has to fulfill the condition within a tolerance range that IT0,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π where I TO,n the breaking current, VDC an intermediate circuit voltage of a commutation circuit comprising the semiconductor switch, C eff1 an effective capacitance of the commutation resonant circuit associated with the semiconductor switch (121), C eff2 an effective capacitance associated with a freewheeling element (142) connected to the semiconductor switch (121) in the commutation circuit, L p an effective electrical inductance of the commutation circuit and n is a natural number; and at least one of the conditions is met: n=2i+1,i∈ℕ; Ceff1≠Ceff2 for=2i+1,i∈ℕ0.

[0066] This ensures that shutdown occurs when the appropriate shutdown current is present. This can be achieved by intervening in the shutdown process and / or by adjusting the current.

[0067] Fig. Figure 3 shows a schematic comparison of two diagrams 341 and 342 on a common time axis t. While diagram 341 shows the current i T1 through the switching element 121 or T1, diagram 342 shows corresponding curves for the current i T2 through the switching element 122 or T2. Schematic curves for different breaking currents I are shown. TO,1 , I TO,3 , I TO,5 , from series I TO,n , where the amplitude of the breaking current decreases for increasing index n. Note that the index n can also have larger values, e.g., 7, 9, 11, or even higher.

[0068] The channel shutdown time t off is shown comparatively long in the schematic representation to allow a clear distinction between curves 321 to 323 in diagram 341. In fact, the channel switch-off time t offbe very short, which would lead to almost overlapping and almost vertical curves in a graphical representation, as is the case, for example, in Fig. 6b. With decreasing current I TO,n the corresponding commutation time t increases ZOS,n as shown in curves 331 to 333 of diagram 342.

[0069] The Fig. 4a to 4c show exemplary voltages v mp via an exemplary semiconductor switch 121 of the device 10 in different operating states.

[0070] The time, current, and voltage specifications of the example measurements shown are merely exemplary and not limiting for the design of the embodiments described herein. Furthermore, for the respective exemplary measurements of I TO,1 , I TO,3 and I TO,5 a representation of the effect of the tolerance range of the breaking current for deviations of e.g. + / -10% is shown.

[0071] The representations of the Fig. 4a, Fig. 4b and Fig. The exemplary measurements shown in Figure 4c differ in the choice of the breaking current I TO,n for n = 1, n = 3 and n = 5, where the case n = 1 serves as a reference and is not within the scope of the embodiments described herein, as long as the capacities C eff1 and C eff2 are identical, but in the event that there are differences in the capacity values.

[0072] First of all, it can be seen that starting from time t start for increasing n, thus decreasing breaking currents of 197 A in Fig. 4a, Fig. 79, Fig. 5 A in Fig. 4b to 50.6 A in Fig. 4c, later times t1, t2, and t3 are reached, respectively, until the voltage reaches an average maximum of 800 V. It is clear to the person skilled in the art that the concept of zero-overvoltage switching is qualitative and that actual freedom from any overshoots or oscillating overvoltages is not achieved in real operation, but that the inventive design keeps the oscillating overvoltages within a range that can be considered interference-free for other elements of the assembly.

[0073] That the selected breaking current I TO,1 ( Fig. 4a), I TO,3 ( Fig. 4b) or I TO,5 ( Fig. 4c) can be an optimal value in each case, is shown in that for the corresponding curves 361, 36'1 and 36", deviations of -10% (curves 362, 36'2 and 36"2) compared to the breaking current and a deviation of +10% (curves 363, 36'3 and 36''3) are shown. These show that a deviation from the respective breaking currents shown in curves 361, 36', and 36''1 can lead to an increase in the oscillating overvoltages and thus to voltage increases. It can be seen that, starting from the respective breaking current, a deviation both towards higher currents and towards lower currents leads to an increase in the oscillating overvoltages, wherein the latter in particular, an increase in the oscillating overvoltages when switching a lower current, is surprising to the person skilled in the art.

[0074] Fig. 5 shows a schematic representation of two curves 381 and 382 over time t and on the ordinate the voltage v mp via the semiconductor switch 121. The curve 382 for the value of n = 2 represents the highest expected overvoltage below the breaking current I TO,1 and explains the advantageous boundary condition of using odd values ​​for the parameter n. The breaking current at which the highest expected overvoltage occurs is I TO,2 reached.

[0075] By using Zero Overvoltage Switching (ZOS), it is possible to switch power semiconductors at maximum switching speed without the occurrence of high turn-off overvoltages. According to the invention, this effect can be adjusted for different turn-off currents. The optimal turn-off currents I discussed herein are TO,Ncan be set within tolerance ranges of + / -30%, + / -20% or + / -10% in order to obtain the advantages according to the invention, an accuracy of + / -10%, + / -5% or + / -2% or less is preferred.

[0076] The cut-off current I to be set TO / I TO,n can be determined from the intermediate circuit voltage V DC , the parasitic inductance L p as well as the parasitic capacitances, which are represented as C in the following formula.

[0077] Compared to a view according to which Iph=2UZK2CLπ where U ZK the intermediate circuit voltage, C the parasitic capacitance and L the parasitic inductance to determine the cut-off current I ph for a single ZOS point, the breaking current is now calculated as follows: IT0,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π

[0078] Compared to applying ZOS at only a specific cut-off current, a larger number of cut-off currents can now be set. This also means that, instead of just one current value, a larger number of current values ​​can be used according to the present invention. This allows for a high degree of freedom in varying the power of the converter system, especially during operation in the partial load range.

[0079] According to the invention, additional advantages are thus obtained, for example compared to a known ZOS in which only one cut-off current can be set and a partial load range would only be possible, for example, when using valley skipping or a burst mode. Although these operating states are also compatible with the exemplary embodiments described here, partial load operation can already be achieved by selecting different cut-off currents, which is advantageous. This also enables advantages over conventional multi-phase converter systems in which individual phases are switched on or off in the partial load range. Paralleling individual phases results in a higher component outlay and thus increased costs, which is avoided by the invention.In these concepts for setting varying power, it is intended that the already known cut-off current is reached in order to be able to apply the ZOS, which is avoided according to the invention by a large number of values ​​for the cut-off current.

[0080] According to the invention, the application range of ZOS is expanded by introducing additional breaking currents. For this purpose, a corresponding number of breaking currents are switched, each with low or minimal switching losses and at least almost no breaking overvoltages. With additional breaking currents, a power electronic converter system can now vary the power range with ZOS. The apt name "extended ZOS area," or eZOSa for short, describes the inventive concept, which enables the power variation of the converter system to be easily implemented.

[0081] When operating power electronic energy converters in the partial load range using only I TO,1 Comparatively large currents may be required. With the inventive introduction of eZOSa, significantly lower currents can be used to provide the required power, especially in the partial load range.

[0082] Embodiments advantageously enable the use of additional possible shutdown currents, for example, to enable the adjustment of the required power of a device in multiple stages. For a specific intermediate circuit voltage, the invention makes it possible to set several discrete current values ​​for a converter system. Utilizing the additional shutdown currents incorporates the advantage of ZOS, which means that operation is possible even in the partial load range at maximum switching speed with minimal resulting shutdown overvoltage. This increases the overall efficiency of the power electronic system. By reducing losses, it is possible to reduce the required cooling, which can have a positive impact on weight, volume, and costs.

[0083] The use of embodiments described herein as eZOSa can make it possible to reduce voltage oscillations in the partial load range, thereby reducing the effort required for filters to continue to ensure compliance with EMC guidelines. Reduced filter effort means that the filter unit can be designed smaller and lighter, which is advantageous.

[0084] The embodiments described herein can be used, for example, in the field of DC / DC converters, including in the field of fuel cell applications, as well as power electronics applications for photovoltaic and storage systems. Alternatively or additionally, applications in power electronics are possible, for example, in electromobility, including on-board chargers and / or in the field of brushless DC motors and BLDC motors.

[0085] Alternatively or additionally, the clock period can be changed so that a given I TO,n leads to different average currents. Suitable means for this are, for example, valley skipping (DCM - Discontinuous Current Mode operation) or burst mode (switching off one or more clock pulses). Alternatively or additionally, the switch-off current can be increased by the value I TO,n within a tolerance range of, for example, + / -20%, + / -10%, or + / -5%. This may cause the device to deviate from the optimal ZOS cut-off current, but it can change the average current accordingly, even if this involves accepting slight overvoltages.

[0086] The embodiments described herein relate to both the Extended ZOS Area, where n > 1 and / or C eff1 ≠ C eff2 A control device described herein can control the cut-off current I TO,nTo do so, it can set the correct switching time within the clock period, for example, using a table, a calculation, an analog circuit, or an approximation. Alternatively or additionally, a control device described herein can set the current using a reference current (such as peak current control), for which purpose a table, a calculation, an analog circuit, or an approximation can be used.

[0087] According to embodiments, a control device may be adaptively configured and / or designed to evaluate the switching process in order to possibly independently readjust the current value, such as in the case of MPP (Maximum Power Point) tracking and / or detection of the overvoltage by a suitable device, such as a diode and an RC memory.

[0088] Embodiments also relate to a control device designed such that its switching speed, current carrying capacity, and / or effective total resistance / total impedance enables the discharging of the gate and the associated switching off of the transistor channel in a shorter time than the period of the commutation resonant circuit. This can be defined as a time t off which describes the duration of the transistor's channel turn-off process. This means that the transistor's channel turn-off time can be set as short as possible, and the transistor turns off as quickly as possible. The duration of the commutation process can vary within the eZOSa, depending on the choice of n. Depending on which n and which turn-off current are chosen, different results can be obtained. In any case, however, the choice of the transistor's channel turn-off time is still very short.

[0089] In the Fig. 6a and Fig. 6b shows exemplary temporal relationships between the different parameters of the embodiments described herein. Reference is made to the block diagram of Fig. 1 and the exemplary equivalent circuit diagram of the Fig. 2. In Fig. 6a shows on a common time axis t a curve 441 which leads to a determined breaking current I TO,n a comparison of the current i Lph (t). The breaking current I TO,n a constant value and when this value is reached by the current I Lph (t) the switching of the semiconductor switch is carried out in accordance with the embodiments described herein. Furthermore, in Fig. 6a a comparison of currents i T1 (t) in curve 442 and the current i T2 (t) shown in curve 443, which within the commutation period t ZOS,nchange accordingly due to the switching process. The current I TO,n The switching operation performed is preferably repeated. The rising curve 441 can be accompanied by a further repeated switching operation when the breaking current is reached again, as is the case with curve 443.

[0090] Fig. Figure 6b shows a more detailed representation of the time interval t ZOS,n out of Fig. 6a, wherein in a transition region 46, the change between an initial value and a final value of curve 443 can be arbitrary and depends on the specific implementation of the circuit. The course of curve 442 indicating the current through semiconductor switch 121 can preferably be steep based on the set turn-off behavior.

[0091] While at the beginning of the time interval t ZOS,n the current i T1(t) in curve 442 at least approximately corresponds to the cut-off current, this is after the end of the switching process for curve 443, which shows the current i T2 (t) is the case. Within the channel shutdown period t off the current falls i T1 (t) to a value associated with the disconnected state of a switch, for example 0. Within the transition region 46 Fig. 6b also shows the increase in voltage v mp via switch 121.

[0092] Although some aspects have been described in connection with a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or component of a device can also be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also represent a description of a corresponding block, detail, or feature of a corresponding device.

[0093] Depending on specific implementation requirements, embodiments of the invention may be implemented in hardware or software. The implementation may be performed using digital signal processing circuits such as microcontrollers, application-specific integrated circuits (ASICs), and / or field-programmable gate arrays (FPGAs), and / or using a digital storage medium.

[0094] In some embodiments, a programmable logic device, such as the aforementioned FPGA, may be used to perform some or all of the functionalities of the methods described herein. In some embodiments, a field-programmable gate array may interact with a microprocessor to perform any of the methods described herein. In general, in some embodiments, the methods are performed by any hardware device. This may be general-purpose hardware, such as a computer processor (CPU), or method-specific hardware, such as an ASIC.

[0095] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein.

Claims

[1] Device with: a switch arrangement with a switching element (121) which is designed to switch off an electrical current path of a commutation circuit, wherein the commutation circuit has a freewheeling element (142) with a parallel-acting capacitance; a control device (18) configured to control the switching element (121) for switching off and for carrying out a switching operation; wherein the control device (18) is designed to provide the switching element (121) with a channel switch-off time (t off ) which is shorter than a period (t res ) a resonant oscillation of the commutation circuit to excite an oscillation in the commutation circuit; wherein the control device (18) is configured for an operating state in which the switching operation is based on a switch-off current (I T0,n) is carried out if, within a tolerance range, it is fulfilled that: IT0,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π where I TO,n the breaking current to be switched off by the switching element (121), V DC an intermediate circuit voltage of the commutation circuit, C eff1 an effective capacitance of the commutation resonant circuit associated with the switching element (121), C eff2 an effective capacitance of the commutation resonant circuit associated with the freewheel element (142), L p an effective electrical inductance of the commutation circuit and n describes a natural number; where at least one of the conditions is met: n=2i+1,i∈ℕ; Ceff1≠Ceff2 for=2i+1,i∈ℕ0. [2] Device according to claim 1, wherein the condition is met that n=2i+1,i∈ℕ. [3] Device according to claim 1 or 2, wherein the condition is met that Ceff1≠Ceff2. [4] Device according to one of the preceding claims, in which the control device (18) is designed to control the cut-off current (I T0,n ) by means of the switching element (121). [5] Device according to claim 4, wherein the control device (18) is designed to control the cut-off current (I T0,n ) based on at least one of reading a database entry, a calculation, an analog circuit, or an approximation. [6] Device according to claim 4 or 5, wherein the control device (18) is designed to control the cut-off current (I T0,n ) by selecting a cut-off current (I T0,n ) assigned switching time. [7] Device according to one of claims 4 to 6, wherein the control device (18) is designed to adjust the cut-off current through the switching element (121) based on a reference current. [8] Device according to one of claims 4 to 7, wherein the control device (18) is designed to evaluate the switching operation for the occurrence of a circuit-induced overvoltage at the switching element (121) in order to obtain an evaluation result which indicates a deviation of the switching parameter from a parameter target value; wherein the control device (18) is designed to determine the switch-off current (I T0,n ) by the switching element (121) to reduce the circuit-induced overvoltage. [9] Device according to one of the preceding claims, wherein the control device (18) is designed to control the switching element (121) based on a reference current value, a setting of a pulse width, or based on a time specification for a switching time. [10] Device according to one of the preceding claims, which is arranged in different operating states to provide a respective predefined average output power, wherein with each of the predefined average output powers a predefined value of the cut-off current (l T0,n ) is associated; wherein the control device (18) is designed to operate the device based on a combination of different predefined values ​​of the cut-off current (I T0,n ) to at least approximate the target output power; or the device using a predefined breaking current (I T0,n ) that has the smallest deviation between the obtained predefined output power and the mean target output power. [11] Device according to claim 10, wherein the control device (18) is designed to determine the average target output power deviating from the different predefined output powers based on at least one of • a temporal change between different predefined values ​​of the breaking current (I TO,n ); • a valley skipping; and • provide a burst mode. [12] Device according to claim 10 or 11, which is designed to provide the mean target output power deviating from the different predefined mean output powers by controlling the device into a mixed operating state in order to switch at least between a first predefined value of the cut-off current (I T0,n ) and a second predefined value of the breaking current (I T0,n ) to change dynamically in order to obtain the mean target output power on average over time; one with a predefined value of the breaking current (I T0,n ) of a predefined average output power associated clock period of the shutdown process in order to achieve a value of the shutdown current (I T0,n ) to obtain a different breaking current; and / or a target value for the breaking current compared to a predefined value of the breaking current (I T0,n ) in order to change an average output current for the output power, accepting increasing overvoltages. [13] Device according to one of the preceding claims, in which the control device (18) is designed to receive intermediate circuit voltage information which indicates an intermediate circuit voltage of the commutation circuit, wherein the control device (18) is designed to determine the cut-off current (I T0,n ) based on the DC link voltage information. [14] Device according to claim 13, wherein the control device (18) is coupled to a data memory in which at least one associated cut-off current information item is stored for a plurality of intermediate circuit voltage information items, wherein the control device (18) is designed to read the cut-off current information item associated with the intermediate circuit voltage information and to determine the cut-off current (I T0,n ) for the switching operation based on the cut-off current information. [15] Device according to one of the preceding claims, wherein the control device (18) is coupled to a data memory in which at least one associated cut-off current information is stored for a plurality of values ​​of an operating parameter, which indicates a target value for the cut-off current, wherein the control device (18) is designed to control the current through the switching element (121) based on the target value. [16] Device according to claim 15, wherein the operating parameter is a first operating parameter and the respectively assigned cut-off current information is first cut-off current information which is assigned to a first value of a second operating parameter; wherein second cut-off current information for the plurality of values ​​of the first operating parameter is stored in the data memory, which is assigned to a second value of the second operating parameter, wherein the control device (18) is designed to read the cut-off current information assigned to the first operating parameter from the data memory based on the first operating parameter and the second operating parameter and to determine therefrom the target value for the cut-off current (I T0,n ) to determine. [17] Device according to one of the preceding claims, in which the control device (18) is designed to receive measured value information associated with a value of an operating state, and in which the control device is designed to determine a target value for the cut-off current (I T0,n ) based on the measured value information. [18] Device according to one of the preceding claims, in which the commutation resonant circuit comprises a discrete inductive or discrete capacitive component which is connected in such a way as to act combinatorially with a parasitic capacitance value or a parasitic inductance value of the commutation resonant circuit and to influence the resonant oscillation. [19] Device according to one of the preceding claims, in which the switching element (121) is designed to be operated in a hard-switching manner during normal operation; and / or in which the control device (18) is designed to hard-switch the switching element (121). [20] Device according to one of the preceding claims, in which the commutation resonant circuit is part of a commutation cell of a power electronic energy converter. [21] A device according to any one of the preceding claims, which is formed as a DC-DC converter comprising one of a boost converter, a buck converter, a half-bridge converter, a full-bridge converter, an inverting converter and a flyback converter. [22] Control device (18) which is designed to switch a switching element (121) to carry out a switch-off process, comprising: wherein the control device (18) is designed to determine, based on a property of the switching element (121), a result which indicates a switch-off current (I T0,n ) flowing through the switching element (121) for the switching process, which, within a tolerance range, satisfies the condition that: IT0,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π where I TO,n the breaking current, V DC an intermediate circuit voltage of a commutation circuit comprising the semiconductor switch, C eff1 an effective capacitance of the commutation resonant circuit associated with the switching element (121), C eff2 an effective capacitance associated with a freewheel element (142) connected to the switching element (121) in the commutation circuit, L pan effective electrical inductance of the commutation circuit and n is a natural number; and at least one of the conditions is met: n=2i+1,i∈ℕ; Ceff1≠Ceff2 for=2i+1,i∈ℕ0 and to switch the switching element (121) based on the result. [23] Control device (18) according to claim 22, wherein the interface is designed to receive the information from a data memory and / or a sensor. [24] Control device (18) according to claim 22 or 23, wherein the control device (18) is designed to control the semiconductor switch based on a reference current value, a setting of a pulse width, or based on a time specification for a switching time. [25] Method for controlling a device with a switch arrangement having a switching element (121) which is designed to switch off an electrical current path of a commutation circuit, wherein the commutation circuit has a freewheeling element (142) with a parallel-acting capacitance; comprising the following steps: Controlling the switching element (121) for switching off and for carrying out a switching operation; so that for the switching operation of the switching element (121) switching is carried out with a channel turn-off time duration which is shorter than a period duration of a resonant oscillation of the commutation circuit in order to excite an oscillation in the commutation circuit; so that the switching operation is based on the breaking current to be switched off (I T0,n ) is carried out if, within a tolerance range, it is fulfilled that: IT0,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π where I TO,nthe breaking current to be switched off by the switching element (121), V DC an intermediate circuit voltage of the commutation circuit, C eff1 an effective capacitance of the commutation resonant circuit associated with the switching element (121), C eff2 an effective capacitance of the commutation resonant circuit associated with the freewheel element (142), L p an effective electrical inductance of the commutation circuit and n is a natural number; and so that at least one of the conditions is met: n=2i+1,i∈ℕ; Ceff1≠Ceff2 for=2i+1,i∈ℕ0. [26] Method for controlling a switching element (121) to carry out a switching-off process, comprising the following steps: based on a property of the switching element (121) and to obtain a result which represents a cut-off current (I T0,n) flowing through the switching element (121) for the switching process, which, within a tolerance range, satisfies the condition that: IT0,n=VDC(Ceff1+Ceff2)3Ceff1Ceff2Lpn π where I TO,n the breaking current, V DC an intermediate circuit voltage of a commutation circuit comprising the semiconductor switch, C eff1 an effective capacitance of the commutation resonant circuit associated with the switching element (121), C eff2 an effective capacitance associated with a freewheel element (142) connected to the switching element (121) in the commutation circuit, L p an effective electrical inductance of the commutation circuit and n is a natural number; and at least one of the conditions is met: n=2i+1,i∈ℕ; Ceff1≠Ceff2 for=2i+1,i∈ℕ0. [27] A computer program comprising a program code for carrying out the method according to claim 25 or 26 when the program runs on a computing device.

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