Capacitive energy store for switchgear assemblies with energy flow control, drive having an energy store of this type, and switchgear assembly having a drive of this type

Abstract

The invention relates to an energy store (10) for an electromagnetic drive of a low-, medium- or high-voltage switch, the energy store (10) comprising one or more capacitors (201, 202, 203) of a first capacitor type and one or more additional capacitors (301, 302, 303, 304, 305) of a second capacitor type, the first capacitor type comprising ceramic capacitors, film capacitors and / or electrolytic capacitors and the second capacitor type being a supercapacitor, and the at least one capacitor (201, 202, 203) of the first capacitor type and the at least one additional capacitor (301, 302, 303, 304, 305) of the second capacitor type being connected to each other in parallel by means of an energy flow regulator (100).

Description

[0001] 2023P19234 DE 1 Description 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. 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 with such a drive. Switchgear for low-, medium-, or high-voltage systems, such as circuit breakers with electrical drives, for example magnetic drives, require a quantity of energy for a switching operation, which is usually stored in capacitors, since the high power required for a switching operation, i.e. the quantity of energy, cannot be provided in a very short time from the auxiliary voltage supply of the switching device.Furthermore, in the event of an auxiliary voltage failure, i.e., a failure of the auxiliary power supply, a switching operation to the safe OPEN position, i.e., open, must be ensured for at least 5 minutes after the auxiliary power supply failure. These two requirements result in the need to design the energy storage device in such a way that, on the one hand, a low electrical internal resistance for the switching energy and, on the other hand, a high storage capacity for the bridging time in the event of an auxiliary power supply failure are provided. Electrolytic capacitors are known from the state of the art as energy storage devices for electromagnetic drives. These are used because, with appropriate dimensioning, electrolytic capacitors can meet both requirements.Both low internal resistance for high short-term power for switching operation and sufficient specific capacitance for the required bridging times in the event of an auxiliary power supply failure are required. Since a correspondingly 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. The object of the invention is to provide an alternative embodiment of the energy storage device that eliminates the disadvantages of the prior art. This object is achieved by independent claim 1 and by the claims dependent thereon.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 has 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 the at least one capacitor of the first capacitor type and the at least one further capacitor of the second capacitor type are connected in parallel to one another via an energy flow controller. In other words, the energy storage device for an electromagnetic drive is a hybrid energy storage device comprising capacitors and supercapacitors, wherein the capacitors are connected to the supercapacitors via an energy flow controller.The capacitors are designed for rapid energy delivery, i.e. high power delivery, to the electromagnetic drive to operate the drive, and the supercapacitors serve as energy storage devices if the auxiliary power supply of a switchgear fails. 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, over a period of at least 5 minutes and thus to be able to carry out at least one opening operation. 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 preferably also the auxiliary power supply.Energy flow control reduces the charging time for the capacitors of the first capacitor type compared to the overall charging time of the hybrid energy storage system, particularly since it is possible to charge only the capacitors of the first capacitor type first and then the capacitors of the second capacitor type. 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 traditional sense; instead, the energy is stored in double layers on the electrodes. Storage occurs both in the form of charge separation in the double layers and in the form of electrochemical storage.In particular, a short charging time until operational readiness for switching operations is achieved by charging the capacitors of the first capacitor type first, followed by charging the capacitors of the second capacitor type. The bridging time in the event of an auxiliary voltage failure is therefore only achieved after the capacitors of the first capacitor type have been charged and after a short waiting period, which, however, is not detrimental to operational management. In addition, 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. At the same time, a longer bridging time in the event of an auxiliary voltage failure is also achieved with the same installation space. It is preferred that the first capacitor type be an electrolytic capacitor.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. It is further preferred that more than one capacitor of the first capacitor type is connected in parallel with one another. It is preferred that more than one further capacitor of the second capacitor type is connected in series with one another.In particular, it is preferred that the energy storage device further comprises a charge balancing circuit, wherein the charge balancing circuit is designed to transfer excess charge from supercapacitors with higher voltage to supercapacitors with lower voltage and / or to prevent the excess charge and / or to discharge the excess charge. The charge balancing circuit is also referred to as a voltage balancing device. The charge balancing circuit prevents overcharging and thus damage to the individual supercapacitors, in particular when the cell voltages of the individual supercapacitors differ. An active charge balancing circuit is particularly preferred. Furthermore, it is particularly preferred that each supercapacitor is connected in parallel to the charge balancing device.It is also particularly preferred that the charge balancing circuit of the energy storage device is constructed without highly integrated, inductive or capacitive components, in particular without coils and capacitors. Such a construction can be implemented, for example, by means of a series connection of one or more Zener diodes and one or more resistors. Alternatively, such a construction is implemented by means of a resistor network in combination with operational amplifiers as voltage followers. It is also preferred that the energy flow control is formed by one or more bidirectional DC-DC converters. It is also preferred that the energy flow control is formed by at least one unidirectional DC-DC converter for each flow direction.A further exemplary embodiment relates to an electromagnetic drive for a vacuum interrupter of a low-, medium-, or high-voltage switchgear, wherein the 2023P19234 DE 6 electromagnetic drive has an energy store according to one or more of the preceding embodiments. Another exemplary 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 embodiments. It is preferred that the one or more further capacitors of the second capacitor type of the energy store store sufficient energy to serve as an auxiliary voltage source for the one or more capacitors of the first capacitor type for 5 minutes or more after a failure of an auxiliary voltage source.It is also preferred that the one or more further capacitors of the second capacitor type of the energy storage device store sufficient energy to serve as an auxiliary voltage source for the 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.A further 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 the one or more capacitors of the first capacitor type serve as an energy source for performing switching operations, and the 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 an auxiliary voltage source failure. 2023P19234 DE 7 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 the energy storage device does not have an additional charging device for the one or more capacitors of the first capacitor type.With regard to the device according to the invention, all statements made above and below regarding the method according to the invention apply correspondingly, and vice versa. In particular, the device according to the invention is designed to carry out the method according to the invention in any desired embodiment or a combination of desired embodiments. With regard to the advantages of the device according to the invention, reference is also made to the advantages described for the method according to the invention. The invention is explained in more detail below using an exemplary embodiment.The specific design of the exemplary embodiment is in no way intended to limit the general design of the method and device according to the invention; rather, individual design features of the exemplary embodiment can be freely combined with one another and with the features described above in any way. Regardless of the grammatical gender of a particular term, persons with male, female, or other gender identities are included. The invention is explained in more detail below with reference to figures. Figure 1: Schematic representation of a switchgear; Figure 2: Exemplary equivalent circuit diagram of an energy storage device according to the invention; 2023P19234 DE 8 Figure 3: Exemplary equivalent circuit diagram of a charge equalization circuit. 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 designed to be analog and / or digital. 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 controller 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 controller 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. Figure 2 also shows capacitors of a first capacitor type 201, 202, 203 connected in parallel, here by way of example three electrolytic capacitors, which 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 circuit of the capacitors of the first capacitor type 201, 202, 203, specifically to the last electrolytic capacitor 203, and supercapacitors 301, 302, 303, 304, 305 are connected in parallel via the energy flow controller 100. Five supercapacitors are connected in series. A charge balancing circuit 400 is optionally arranged in parallel with each capacitor. Figure 3 shows an example equivalent circuit diagram of a charge balancing circuit 400 for five supercapacitors 301, 302, 303, 304, 305.2023P19234 DE 9 The charge equalization circuit 400 has a voltage divider, here for example a resistor network with five resistors 410, 420, 430, 440, 450 as a voltage divider between a first potential 401, here for example a ground potential, and a second potential 402, here for example a positive voltage V. +,. Furthermore, the charge balancing circuit 400 has, 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. However, since the actual capacitances of capacitors can deviate from the nominal capacitances, deviations in the range of ±5% to ±20% are possible, the charge equalization circuit 400 is constructed in such a way that the theoretical charge voltage is divided by means of the resistor network of resistors 410, 420, 430, 440, 450 as a voltage divider, and 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 achieve a voltage equalization according to the respective Capacitances of the respective supercapacitors 301, 302, 303, 304, 305.For this purpose, the inverting input of each operational amplifier 415, 425, 435, 445 is directly connected to the output of the respective operational amplifier 415, 425, 435, 445. The operational amplifiers 415, 425, 435, 445 are each supplied with voltage by two cells, in this case supercapacitors 301, 302, 303, 304, 305. The operational amplifier 445, referred to here as the lowest operational amplifier 445, is supplied with voltage by ground contact 401 and the cell above it, i.e., at the output of the operational amplifier 435, in this case supercapacitor 302. The overlying operational amplifier 435 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.The operational amplifier 425 is powered by the cell containing the output of operational amplifier 435, here supercapacitor 302, and the cell containing the output of operational amplifier 415, here supercapacitor 304. The top operational amplifier 415 is powered by the cell containing the output of operational amplifier 425, here 303, and the cell with the input voltage 402, here supercapacitor 305. If 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 charge required for this is then taken from one of the neighboring supercapacitors 301, 302, 303, 304, 305.If one or more supercapacitors 301, 302, 303, 304, 305 have 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 neighboring supercapacitors 301, 302, 303, 304, 305. The charge balancing circuit 400 thus reduces the voltages of supercapacitors 301, 302, 303, 304, 305 with too high a voltage and increases the voltages of supercapacitors 301, 302, 303, 304, 305 with too low a voltage. In this way, charge equalization is achieved. In particular, such a charge equalization circuit 400 does not have any highly integrated, inductive or capacitive components, in particular no coils or other capacitors.

[0002] 2023P19234 DE 12 List of reference symbols 1 Switchgear; 4 Display on the switchgear 1; 6 User interface of the switchgear 1; 10 Energy storage device; 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 capacitor type, e.g. electrolytic capacitor; 202 Capacitor of a first capacitor type, e.g. electrolytic capacitor; 203 Capacitor of a first capacitor type, e.g.Electrolytic capacitor; 301 Capacitor of a second capacitor type, a supercapacitor; 302 Capacitor of a second capacitor type, a supercapacitor; 303 Capacitor of a second capacitor type, a supercapacitor; 304 Capacitor of a second capacitor type, a supercapacitor; 305 Capacitor of a second capacitor type, a supercapacitor; 400 Charge balancing circuit; 401 First potential, for example ground potential; 402 Second potential, for example positive voltage V. + ; 410 resistance of the voltage divider; 415 operational amplifier; 420 resistance of the voltage divider; 425 operational amplifier; 2023P19234 DE 13 430 resistance of the voltage divider; 435 operational amplifier; 440 resistance of the voltage divider; 445 operational amplifier; 450 resistance of the voltage divider.

Claims

2023P19234 DE 14 Patent claims 1. Energy storage device (10) for an electromagnetic drive of a low-, medium- or high-voltage switch, characterized in that - the energy storage device (10) has one or more capacitors (201, 202, 203) of a first capacitor type and one or more further capacitors (301, 302, 303, 304, 305) 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 - 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 one another via an energy flow control (100). are interconnected.

2. Energy storage device (10) according to claim 1, characterized in that the first capacitor type is an electrolytic capacitor. 3.Energy storage device (10) according to one of the preceding claims, characterized in that ^ the first capacitor type has an energy density of a maximum of 0.5 Wh / l and the second capacitor type has a power density of at least 3 Wh / l, and / or ^ the second capacitor type has an energy density which 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. 2023P19234 DE 15 4. Energy storage device (10) according to one of the preceding claims, characterized in that more than one capacitor (201, 202, 203) of the first capacitor type are connected in parallel with one another.

5. Energy storage device (10) according to one of the preceding claims, characterized in that more than one capacitor (301, 302, 303, 304, 305) of the second capacitor type are connected in series with one another.

6. Energy storage device (10) according to claim 5, characterized in that the energy storage device (10) further comprises a charge balancing circuit (400), wherein the charge balancing circuit (400) is configured to transfer excess charges from higher-voltage supercapacitors to lower-voltage supercapacitors and / or to prevent the excess charge and / or to dissipate the excess charge. 7.Energy storage device (10) according to claim 6, characterized in 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 one of the preceding claims, characterized in that the energy flow control (100) is formed by one or more bidirectional DC-DC converters. 2023P19234 DE 16 9. Energy storage device (10) according to one of the preceding claims, characterized in that the energy flow control (100) is formed by at least one unidirectional DC-DC converter for each flow direction.

10. Electromagnetic drive for a vacuum interrupter of a low-, medium-, or high-voltage switchgear (1), characterized in 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 in 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 in that the one or more further 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 the 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 in that the one or more further capacitors (301, 302, 303, 304, 305) of the second capacitor type of the energy storage device (10) store sufficient energy to. 2023P19234 DE 17 to serve as an auxiliary voltage source for the 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 a switching cycle of the vacuum interrupter from opening - closing - and reopening.

14. Method for operating a low-, medium- or high-voltage switchgear (1), characterized in that the low-, medium- or high-voltage switchgear (1) has an electromagnetic drive according to one of the preceding claims, and the one or more capacitors (201, 202, 203) of the first capacitor type serve as an energy source for carrying out switching operations, and the one or more further 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. A method for operating a low-, medium- or high-voltage switchgear according to claim 14, characterized in 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 store (10) has no additional charging device for the one or more capacitors (201, 202, 203) of the first capacitor type.

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