Capacitive energy storage device for switchgear with energy flow control, a drive with such an energy storage device, and a switchgear with such a drive.

Abstract

Energy storage device (10) for an electromagnetic drive of a low, medium or high voltage switch, wherein - the energy storage device (10) comprises one or more capacitors (201, 202, 203) of a first type of capacitor and one or more further capacitors (301, 302, 303, 304, 305) of a second type of capacitor, - wherein the first capacitor type comprises ceramic, film and / or electrolytic capacitors and the second capacitor type is a supercapacitor, and characterized in that the at least one capacitor (201, 202, 203) of the first capacitor type and the at least one further capacitor (301, 302, 303, 304, 305) of the second capacitor type are connected in parallel to each other via an energy flow control (100) and the energy flow control is designed to regulate the energy flow between the capacitors of the first capacitor type and the further capacitors of a second capacitor type and also the auxiliary voltage supply and initially only charge the capacitors of the first capacitor type and only afterwards the capacitors of the second capacitor type.

Description

[0001] The invention relates to a capacitive energy storage device with energy flow control for switchgear, a drive with such an energy storage device and a switchgear device with such a drive.

[0002] Switching devices for low, medium or high voltage systems, such as circuit breakers with electric drives, i.e. magnetic drives, require a certain amount of energy for a switching operation, which is usually stored in capacitors, since the auxiliary voltage supply of the switching device cannot provide the high power, i.e. the amount of energy, required for a switching operation in a very short time.

[0003] Furthermore, the requirement must be regularly met that in the event of an auxiliary voltage failure, i.e. a failure of the auxiliary voltage supply, a switching operation to the safe switching position OPEN, i.e. open or opened, must be guaranteed for at least 5 minutes after the auxiliary voltage supply failure.

[0004] These two requirements necessitate the design of the energy storage device in such a way that, on the one hand, a low internal electrical resistance is provided for the switching energy, and on the other hand, a high storage capacity is provided for the bridging time in the event of an auxiliary power supply failure.

[0005] Electrolytic capacitors are known from the prior art as energy storage devices for electromagnetic drives. They are used because, with appropriate dimensioning, electrolytic capacitors can fulfill both requirements: low internal resistance for high short-term power during switching operations and sufficient specific capacitance for the necessary bridging times in the event of an auxiliary power supply failure.

[0006] From DE 100 27 007 A1 a combination of double-layer capacitors and an electrolytic capacitor for a protective device for vehicle occupants is known.

[0007] US patent 2002 / 0017822A1 discloses an energy control system for a power supply for powering a load with energy storage devices, which includes double-layer capacitors and an electrolytic capacitor.

[0008] A power supply with double-layer capacitors and an electrolytic capacitor connected in parallel with the double-layer capacitors is disclosed in JP 2004 - 364 422 A.

[0009] From CN 2 08 077 869 U, a power supply for a vacuum circuit breaker is known in which supercapacitors supply energy to the drive of the vacuum circuit breaker.

[0010] DE 197 08 842 A1 relates to a switching arrangement for charge equalization of capacitors.

[0011] A balancing circuit for energy storage elements connected in series is known from DE 103 26 934 A1.

[0012] Since a sufficiently high number of electrolytic capacitors must be provided to ensure a sufficiently long bridging time in the event of an auxiliary power supply failure, the costs for such an electrolytic capacitor assembly are high, as is the required installation space.

[0013] The object of the invention is now to provide an alternative design of the energy storage device that eliminates the disadvantages of the prior art.

[0014] The problem is solved by independent claim 1 and by the dependent claims.

[0015] One embodiment relates to an energy storage device for an electromagnetic drive of a low-, medium- or high-voltage switch, wherein the energy storage device comprises one or more capacitors of a first capacitor type and one or more further capacitors of a second capacitor type, wherein the first capacitor type comprises ceramic, film and / or electrolytic capacitors and the second capacitor type is a supercapacitor, and wherein where at least one capacitor of the first capacitor type and at least one further capacitor of the second capacitor type are connected in parallel to each other via an energy flow control.

[0016] In other words, the energy storage device for an electromagnetic drive is a hybrid energy storage system consisting of capacitors and supercapacitors, with the capacitors connected to the supercapacitors via an energy flow controller. The capacitors are designed for rapid energy delivery, i.e., high power output, to the electromagnetic drive to operate the drive, while the supercapacitors serve as energy storage in the event of a failure of the auxiliary power supply to a switchgear. In the event of a failure of the auxiliary power supply, the supercapacitors are designed to take over the function of the auxiliary power supply and preferably provide a sufficient operating voltage to charge the capacitors, and thus to switch the switching device, for a period of at least 5 minutes, enabling at least one opening operation.

[0017] The energy flow control is designed to regulate the energy flow between the capacitors of the first capacitor type and the further capacitors of a second capacitor type, as well as the auxiliary voltage supply.

[0018] The energy flow control reduces the charging time for the capacitors of the first capacitor type compared to the total charging time of the hybrid energy storage system, especially since it is possible to initially charge only the capacitors of the first capacitor type and only later charge the capacitors of the second capacitor type.

[0019] Supercapacitors are also known as electrochemical capacitors or ultracapacitors and are characterized by the fact that they generally do not have a dielectric in the conventional sense, but rather the energy is stored in double layers on the electrodes, with storage occurring both in the form of charge separation in the double layers and in the form of electrochemical storage.

[0020] In particular, a short charging time until the system is ready for switching operations is achieved first by charging the capacitors of the first type, followed by charging the capacitors of the second type. The bridging time in the event of an auxiliary power failure is therefore only reached after the capacitors of the first type have been charged and after a short waiting period, which, however, does not negatively affect operation.

[0021] Additionally, the use of supercapacitors ensures a longer bridging time in the event of an auxiliary voltage failure, without increasing the charging times of the capacitors of the first capacitor type.

[0022] At the same time, a longer bridging time in the event of an auxiliary power failure is also achieved with the same installation space.

[0023] It is preferred that the first type of capacitor is an electrolytic capacitor.

[0024] It is also preferred that the first capacitor type has an energy density of at most 0.5 Wh / l and the second capacitor type has an energy density of at least 3 Wh / l, and / or that the second capacitor type has an energy density that is at least 5 times higher than that of the first capacitor type, and wherein the first capacitor type has a lower internal resistance than the second capacitor type.

[0025] Furthermore, it is preferred that more than one capacitor of the first capacitor type is connected in parallel with each other.

[0026] It is preferred that more than one additional capacitor of the second capacitor type is connected in series with each other.

[0027] It is particularly preferred that the energy storage device further comprises a charge balancing circuit, wherein the charge balancing circuit is configured to transfer excess charges from higher-voltage supercapacitors to lower-voltage supercapacitors and / or to prevent excess charging and / or to dissipate excess charge. The charge balancing circuit is also referred to as a voltage equalization device. The charge balancing circuit prevents overcharging and thus damage to the individual supercapacitors, especially when the cell voltages of the individual supercapacitors differ.

[0028] An active charge balancing circuit is particularly preferred.

[0029] Furthermore, it is particularly preferred that each supercapacitor is connected in parallel to the charge balancing device.

[0030] It is particularly preferred that the charge balancing circuit of the energy storage device be constructed without highly integrated inductive or capacitive components, especially without coils and capacitors. Such a construction can be achieved, for example, by means of a series connection of one or more Zener diodes and one or more resistors. Alternatively, such a construction can be achieved using a resistor network in combination with operational amplifiers as voltage followers.

[0031] It is also preferred that the energy flow control is formed by one or more bidirectional DC-DC converters.

[0032] It is also preferred that the energy flow control is formed by at least one unidirectional DC-DC converter for each flow direction.

[0033] Another embodiment relates to an electromagnetic drive for a vacuum interrupter of a low-, medium- or high-voltage switchgear, wherein the electromagnetic drive has an energy storage device according to one or more of the above embodiments.

[0034] Another embodiment relates to a low-, medium- or high-voltage switchgear, wherein the low-, medium- or high-voltage switchgear has an electromagnetic drive according to the preceding descriptions.

[0035] It is preferred that one or more additional capacitors of the second capacitor type of the energy storage device store sufficient energy to serve as an auxiliary voltage source for one or more capacitors of the first capacitor type for 5 minutes or more after a failure of an auxiliary voltage source.

[0036] It is also preferred that one or more additional capacitors of the second capacitor type of the energy storage device store sufficient energy to serve as an auxiliary voltage source for one or more capacitors of the first capacitor type for 5 minutes or more after a failure of an auxiliary voltage source, and to enable a switching cycle of opening - closing - and reopening.

[0037] Another embodiment relates to a method for operating a low-, medium- or high-voltage switchgear, wherein the low-, medium- or high-voltage switchgear has an electromagnetic drive according to one of the preceding embodiments, and one or more capacitors of the first capacitor type serve as an energy source for performing switching operations, and one or more further capacitors of the second capacitor type replace the failed auxiliary voltage source for 5 minutes or more in the event of a failure of an auxiliary voltage source.

[0038] It is also preferred that the one or more capacitors of the first capacitor type are charged by a controllable DC-DC converter present in the energy flow control and that the energy storage device does not have an additional charging device for the one or more capacitors of the first capacitor type.

[0039] With regard to the apparatus according to the invention, all descriptions given above and below concerning the method according to the invention apply accordingly, and vice versa. In particular, the apparatus according to the invention is configured to carry out the method according to the invention in any embodiment or combination of embodiments. Reference is also made to the advantages described in relation to the method according to the invention with regard to the apparatus according to the invention.

[0040] The invention is explained in more detail below with reference to an exemplary embodiment. The specific design of the exemplary embodiment is in no way to be understood as restrictive for the general design of the method and the device according to the invention; rather, individual features of the exemplary embodiment can be freely combined with each other and with the features described above in any way.

[0041] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

[0042] The invention will be explained in more detail below using figures. Fig. 1: Schematic representation of a switchgear; Fig. 2: Exemplary equivalent circuit diagram of an energy storage device according to the invention; Fig. 3: Example of an equivalent circuit diagram of a charge equalization circuit.

[0043] The Fig. Figure 1 shows a schematic representation of a switchgear 1 with displays 4 and a user interface 6. The displays 4 and the user interface 6 are implemented analogously and / or digitally.

[0044] The Fig. Figure 2 shows an exemplary equivalent circuit diagram of an energy storage device 10 according to the invention. The energy storage device 10 has an energy flow control 100 for connecting the energy storage device 10 to an electromagnetic drive and an auxiliary voltage source of a switchgear 1, wherein the energy flow control 100 is further designed to regulate, i.e. control, the energy flow between the capacitors 201, 202, 203 of a first capacitor type and the further capacitors 301, 302, 303, 304, 305 of a second capacitor type.

[0045] Furthermore, the Fig. Two capacitors of the first capacitor type 201, 202, 203, shown here as an example of three electrolytic capacitors, are connected in parallel and are designed to supply the electromagnetic drive with electrical energy for at least one switching operation. The energy flow controller 100 is connected to the parallel connection of the capacitors of the first capacitor type 201, 202, 203, specifically to the last electrolytic capacitor 203. Supercapacitors 301, 302, 303, 304, 305, shown here as an example of five supercapacitors, are connected in parallel via the energy flow controller 100. The supercapacitors are connected in series with each other. A charge equalization circuit 400 is optionally arranged in parallel with each capacitor.

[0046] The Fig. Figure 3 shows an exemplary equivalent circuit diagram of a charge balancing circuit 400 for five supercapacitors 301, 302, 303, 304, 305 as examples.

[0047] The charge equalization circuit 400 has a voltage divider, here exemplified by a resistor network with five resistors 410, 420, 430, 440, 450, as a voltage divider between a first potential 401, here exemplified by a ground potential, and a second potential 402, here exemplified by a positive voltage V +, on. Furthermore, the charge balancing circuit 400 features, for example, four operational amplifiers 415, 425, 435, 445. The voltage difference between the first potential 401 and the second potential 402 corresponds to the theoretical charging voltage of the supercapacitors 301, 302, 303, 304, 305. Since the actual capacitances of capacitors can deviate from their nominal capacitances (deviations of ±5% to ±20% are possible), the charge equalization circuit 400 is designed such that the theoretical charging voltage is divided by means of the resistor network consisting of resistors 410, 420, 430, 440, 450 as a voltage divider. In the case of differing capacitances of the supercapacitors 301, 302, 303, 304, 305, the operational amplifiers 415, 425, 435, 445 act as voltage followers to equalize the voltage according to the respective capacitances of the respective supercapacitors 301, 302, 303, 304, 305. 303, 304, 305 lead.The inverting input of each operational amplifier 415, 425, 435, 445 is directly connected to its output. The operational amplifiers 415, 425, 435, 445 are each powered by two cells, in this case supercapacitors 301, 302, 303, 304, 305.

[0048] The operational amplifier 445, referred to here as the lowest operational amplifier 445, is supplied with voltage via the earth contact 401 and the cell above it, i.e. at the output of the operational amplifier 435, here supercapacitor 302.

[0049] The operational amplifier 435 above is supplied with voltage by the cell with the output of the operational amplifier 445, here supercapacitor 301, and the cell with the output of the operational amplifier 425, here supercapacitor 303.

[0050] The operational amplifier 425 is supplied with voltage by the cell with the output of the operational amplifier 435, here supercapacitor 302, and the cell with the output of the operational amplifier 415, here supercapacitor 304.

[0051] The top operational amplifier 415 is supplied with voltage by the cell with the output of the operational amplifier 425, here 303, and the cell with the input voltage 402, here supercapacitor 305.

[0052] Should one or more supercapacitors 301, 302, 303, 304, 305 have a lower voltage than the desired capacitor voltage, the respective operational amplifier 415, 425, 435, 445 acts as a current source and charges the respective supercapacitor 301, 302, 303, 304, 305. The required charge is then taken from one of the adjacent supercapacitors 301, 302, 303, 304, 305.

[0053] Should one or more supercapacitors 301, 302, 303, 304, 305 exhibit a higher voltage than the desired capacitor voltage, the operational amplifier 415, 425, 435, 445 acts as a current sink and discharges the respective supercapacitor 301, 302, 303, 304, 305. The excess charge is then absorbed by one of the adjacent supercapacitors 301, 302, 303, 304, 305.

[0054] The charge balancing circuit 400 reduces voltages of supercapacitors 301, 302, 303, 304, 305 that are too high and increases voltages of supercapacitors 301, 302, 303, 304, 305 that are too low. This achieves charge equalization. In particular, such a charge balancing circuit 400 does not contain any highly integrated, inductive, or capacitive components, especially no coils or additional capacitors. Reference symbol list 1 Switchgear; 4 Display on switchgear 1; 6 User interface of switchgear 1; 10 Energy storage devices; 100 Energy flow control for connecting the energy storage device 10 to an electromagnetic drive and an auxiliary voltage source of a switchgear 1 and for controlling the energy flow between the capacitors of a first capacitor type and the further capacitors of a second capacitor type; 201 Capacitor of a first type of capacitor, e.g. electrolytic capacitor; 202 Capacitor of a first type of capacitor, e.g. electrolytic capacitor; 203 Capacitor of a first type of capacitor, e.g. electrolytic capacitor; 301 Capacitor of a second type of capacitor, a supercapacitor; 302 Capacitor of a second type of capacitor, a supercapacitor; 303 Capacitor of a second type of capacitor, a supercapacitor; 304 Capacitor of a second type of capacitor, a supercapacitor; 305 Capacitor of a second type of capacitor, a supercapacitor; 400 charge balancing circuit; 401 first potential, for example Earth potential; 402 second potential, for example positive voltage V + ; 410 Resistance of the voltage divider; 415 operational amplifiers; 420 Resistance of the voltage divider; 425 operational amplifiers; 430 Resistance of the voltage divider; 435 operational amplifiers; 440 Resistance of the voltage divider; 445 operational amplifiers; 450 resistance of the voltage divider.

Claims

[1] Energy storage device (10) for an electromagnetic drive of a low, medium or high voltage switch, wherein - the energy storage device (10) comprises one or more capacitors (201, 202, 203) of a first type of capacitor and one or more further capacitors (301, 302, 303, 304, 305) of a second type of capacitor, - where the first capacitor type includes ceramic, film and / or electrolytic capacitors and the second capacitor type is a supercapacitor, and characterized by, that the at least one capacitor (201, 202, 203) of the first capacitor type and the at least one further capacitor (301, 302, 303, 304, 305) of the second capacitor type are connected in parallel to each other via an energy flow control (100) and the energy flow control is designed to regulate the energy flow between the capacitors of the first capacitor type and the further capacitors of a second capacitor type and also the auxiliary voltage supply and initially only charge the capacitors of the first capacitor type and only afterwards the capacitors of the second capacitor type. [2] Energy storage device (10) according to claim 1, characterized by , that the first type of capacitor is an electrolytic capacitor. [3] Energy storage device (10) according to any one of the preceding claims, characterized by , that • the first capacitor type has a maximum energy density of 0.5 Wh / l and the second capacitor type has a power density of at least 3 Wh / l, and / or • the second type of capacitor has an energy density that is at least 5 times higher than that of the first type of capacitor, and wherein the first type of capacitor has a lower internal resistance than the second type of capacitor. [4] Energy storage device (10) according to any one of the preceding claims, characterized by , that more than one capacitor (201, 202, 203) of the first capacitor type are connected in parallel with each other. [5] Energy storage device (10) according to any one of the preceding claims, characterized by , that more than one capacitor (301, 302, 303, 304, 305) of the second capacitor type are connected in series. [6] Energy storage device (10) according to claim 5, characterized by, that the energy storage device (10) further comprises a charge balancing circuit (400), wherein the charge balancing circuit (400) is designed to transfer excess charges from higher voltage supercapacitors to lower voltage supercapacitors and / or to prevent excess charge and / or to dissipate excess charge. [7] Energy storage device (10) according to claim 6, characterized by , that the charge balancing circuit (400) of the energy storage device is constructed without highly integrated, inductive or capacitive components, in particular without coils and capacitors. [8] Energy storage device (10) according to any one of the preceding claims, characterized by , that the energy flow control (100) is formed by one or more bidirectional DC-DC converters. [9] Energy storage device (10) according to any one of the preceding claims, characterized by, that the energy flow control (100) is formed by at least one unidirectional DC-DC converter for each flow direction. [10] Electromagnetic actuator for a vacuum switching tube of a low, medium or high voltage switchgear (1), characterized by , that the electromagnetic drive has an energy storage device (10) according to one of the preceding claims. [11] Low, medium or high voltage switchgear (1), characterized by , that the low, medium or high voltage switchgear (1) has an electromagnetic drive according to the preceding claim. [12] Low, medium or high voltage switchgear (1) according to claim 11, characterized by, that one or more additional capacitors (301, 302, 303, 304, 305) of the second capacitor type of the energy storage device (10) store sufficient energy to serve as an auxiliary voltage source for one or more capacitors (201, 202, 203) of the first capacitor type for 5 minutes or more after a failure of an auxiliary voltage source. [13] Low, medium or high voltage switchgear (1) according to claim 11, characterized by , that one or more additional capacitors (301, 302, 303, 304, 305) of the second capacitor type of the energy storage device (10) store sufficient energy to serve as an auxiliary voltage source for one or more capacitors (201, 202, 203) of the first capacitor type for 5 minutes or more after a failure of an auxiliary voltage source and to enable one switching cycle of the vacuum switching tube of opening - closing - and reopening. [14] Method for operating a low, medium or high voltage switchgear (1), characterized by , that the low-, medium- or high-voltage switchgear (1) has an electromagnetic drive according to claim 10, and one or more capacitors (201, 202, 203) of the first type serve as an energy source for performing switching operations, and one or more additional capacitors (301, 203, 303, 304, 305) of the second capacitor type replace the failed auxiliary voltage source for 5 minutes or more in the event of a failure of an auxiliary voltage source. [15] Method for operating a low-, medium- or high-voltage switchgear according to claim 14, characterized by, that the one or more capacitors (201, 202, 203) of the first capacitor type are charged by a controllable DC-DC converter present in the energy flow control (100) and the energy storage device (10) does not have an additional charging device for the one or more capacitors (201, 202, 203) of the first capacitor type.

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