Intelligent switching device

Abstract

Switching device comprising at least one mechanical switch and / or semiconductor switch, at least one device for measuring the current flowing through the switching device and at least one first device for measuring the voltage, wherein at least one second device for measuring the voltage is provided and the first device for measuring the voltage, the at least one mechanical switch and / or semiconductor switch and the at least one second device for measuring the voltage are connected in series.

Description

[0001] The present invention relates to a switching device comprising at least one mechanical switch and / or semiconductor switch, at least one device for measuring the current flowing through the switching device and at least one first device for measuring the voltage.

[0002] A generic switching device with at least one mechanical switch and / or at least one semiconductor switch is typically used as a secondary switch. The switching device is typically controlled by an external system. For safe and reliable operation of the switch or contactor, the recording of physical variables such as voltage, current, power, power factor, or temperature in and around the switch is necessary. Previously, this data was recorded using additional measuring devices. The disadvantage of such known switching devices is that they require the use of external systems and require additional installation space.

[0003] It is therefore the object of the present invention to provide an improved switching device which eliminates the problems known from the prior art, which in particular dispenses with external systems and has only a small installation space requirement, as well as generally the provision of an energy management system in power supply systems and the provision of fast protection devices in DC systems.

[0004] The object is achieved by the features of independent claim 1. Accordingly, in a switching device according to the preamble of independent claim 1, the object is achieved according to the invention if at least one second device for measuring the voltage is provided, wherein the first device for measuring the voltage, the at least one mechanical switch and / or semiconductor switch and the at least one second device for measuring the voltage are connected in series.

[0005] In the solution according to the invention, both a device for measuring current, such as a current sensor, and at least a first and a second device for measuring voltage are integrated into the switching device. This provides intelligence within the system and allows for local decisions. Therefore, additional external measuring devices are not required. This results in a compact design with minimal installation space requirements.

[0006] Advantageous embodiments of the present invention are the subject of the subclaims.

[0007] In a preferred embodiment of the present invention, the switching device is designed for direct current applications. This allows for the provision of a fast protection device for a direct current system. This is particularly necessary for direct current systems, as these systems tend to operate capacitively, requiring a significantly rapid current rise to be switched off. In direct current networks, these components are essential for sector protection and monitoring.

[0008] In a further preferred embodiment of the present invention, the switching device is bidirectional. The switching device can therefore be used in all applications requiring bidirectionality. This is the case when the sector to be protected functions not only as an energy consumer but also as an energy producer.

[0009] In a particularly compact embodiment, it can be provided that the at least one mechanical switch and / or semiconductor switch, the device for measuring the current, the first device for measuring the voltage and the second device for measuring the voltage are arranged in a common housing.

[0010] Yet another preferred embodiment of the present invention may provide for an evaluation unit to be arranged in the common housing. This allows faults or special events to be directly detected locally and treated preventively.

[0011] Preferably, a communications unit can also be arranged in the common housing. This allows for monitoring of local variables as well as direct external communication, particularly in the event of errors or special events.

[0012] A further preferred embodiment of the present invention provides that a first semiconductor module with a first semiconductor switch, a mechanical switch and a second semiconductor module with a second semiconductor switch are arranged in series one behind the other, wherein the two semiconductor modules are arranged anti-serially due to the unidirectional switching capacity so that the complete switch has bidirectional switching capacity. In this case, the switching device therefore comprises two semiconductor switches, a mechanical switch, the device for measuring the current, i.e. a current sensor, and a first and a second device for measuring the voltage. This provides a hybrid switch, i.e. a switch which comprises both semiconductor-based switching elements and electromechanical switching elements, such as a contactor, with the associated advantages. This hybrid switch is characterized in that thethe semiconductor-based switching element(s) and the electromechanical switching element are in series.

[0013] Preferably, the semiconductor modules are designed as identical parts. The associated advantages include, in particular, reduced costs.

[0014] Advantageously, it can also be provided that the semiconductor modules are bidirectional. For this purpose, each of the semiconductor modules can have a semiconductor switch and a freewheeling diode or body diode arranged in parallel. This body diode is typically an intrinsic component of the semiconductor switch. The current can then flow bidirectionally through the semiconductor modules, depending on the current direction via the semiconductor switch or the corresponding freewheeling diode or body diode. Consequently, the semiconductor module only has unidirectional switching capacity.

[0015] A further preferred embodiment of the present invention provides that the semiconductor switches of the semiconductor modules are designed as field-effect transistors, e.g., MOSFETs. This enables scalability of the on-resistance or the minimum on-resistance r DS,on in parallel connection of semiconductor modules, which leads to a reduction in the power loss of the semiconductor module during operation. In comparison, IGBTs as semiconductor modules have a minimum saturation voltage V CE(SAT) , which means that parallelization does not lead to a reduction in power loss.

[0016] Yet another preferred embodiment of the present invention provides that the source terminals of the semiconductor modules are connected to one another via the at least one mechanical switch. This is thus an anti-serial circuit, with the source terminals of the semiconductor switches being connected to one another.

[0017] A simple design of the switching device can be achieved by connecting each of the semiconductor modules to one of the busbars by means of a connection element and to external terminals of the switching device by means of a further connection element. The connection elements can preferably be designed as solid terminal blocks and enable the conduction of high currents.

[0018] An additional cost reduction can be achieved by designing the connecting elements as identical parts.

[0019] Yet another preferred embodiment of the present invention provides that the switching device comprises busbars for contacting the at least one mechanical switch and / or the at least one semiconductor switch, wherein a receptacle is formed in at least one of the busbars in which the device for measuring the current is arranged. This enables simple implementation of the current measurement. The solution can also be integrated into existing switches and contactors.

[0020] Embodiments of the present invention are explained in more detail below with reference to the drawings. They show: Fig. 1 Schematic representation of a first embodiment of a switching device according to the invention; Fig. 2 Circuit diagram of the switching device from Fig. 1; Fig. 3 Circuit diagram of a second embodiment of a switching device according to the invention; Fig. 4 Circuit diagram of a third embodiment of a switching device according to the invention; Fig. 5 perspective view of a further embodiment of a switching device according to the invention; Fig. 6 perspective view of a further embodiment of a switching device according to the invention; Fig. 7 schematic representation of the switching device from Fig. 6; Fig. 8 Simplified circuit diagram of the switching device from Fig. 6; Fig. 9 Overview of the functions of the evaluation of a switching device according to the invention; Fig. 10 Overview of further functions of the evaluation of a switching device according to the invention;

[0021] In the following explanations, identical parts are designated by identical reference numerals. Where a figure contains reference numerals that are not further explained in the corresponding figure description, reference is made to preceding or subsequent figure descriptions.

[0022] Fig. 1 shows a schematic representation of a first embodiment of a switching device 1 according to the invention. The switching device 1 comprises at least one switch 2, which can be designed as a mechanical switch, for example as a contactor, and / or as a semiconductor switch. A first measuring device 3 is arranged upstream of the switch 2. The first measuring device 3 comprises a device for measuring the current, e.g. a current sensor, and a first device for measuring the voltage. A second measuring device is arranged downstream of the switch 2. The second measuring device comprises a device for measuring the voltage 4. The switch 2, the first measuring device 3 and the second measuring device 4 are designed to enable a bidirectional current flow.

[0023] The switching device 1 further comprises an evaluation unit 5. The first measuring device 3 and the second measuring device 4 transmit the measured values ​​to the evaluation unit 5. The evaluation unit 5 communicates with the switch 2. The evaluation unit 5 is designed to carry out protection and monitoring functions of the switching device 1 or the switch 2. The evaluation unit can be designed in digital and / or analog form. In digital form, the evaluation unit can comprise microcontrollers or programmable logic units, e.g. FPGAs. The evaluation unit 5 further communicates with a communication unit 6. The communication unit 6 is likewise integrated into the switching device 1. The switching device 1 preferably has a common housing (not shown) in which the switch 2, the first measuring device 3, the second measuring device 4, the evaluation unit 5 and the communication unit 6 are arranged.External communication, for example via Ethernet, USB and / or other fieldbus systems, is possible via the communication unit 6.

[0024] Typically, switch 2 is used as a secondary switch. The inventive design enables a combination of the secondary switch 2 with measurement, evaluation, and communication technology. An intelligent switching device 1 is provided. Real-time information, such as current and voltage, can be evaluated through measurement. Based on rules, the evaluation unit 5 can determine whether a fault has occurred. In the event of a fault, protection of switch 2 and the load or source is possible. Monitoring functions can be implemented in the switching device 1. For example, real-time data monitoring and forwarding via interfaces can be implemented.

[0025] Fig. 2 shows a circuit diagram of the switching device 1 from Fig. 1. As already described, the switching device 1 has a first measuring device 3. The first measuring device 3 comprises a first device for measuring the voltage 3.1 and a device for measuring the current 3.2. The switch 2 is arranged in series behind it. Fig. 2, the switch is designed as a mechanical switch, in particular as a contactor 2.1. The second device for measuring the voltage 4 is arranged in series behind the contactor 2.1. The first device for measuring the voltage 3.1, the device for measuring the current 3.2 and the second device for measuring the voltage 4 communicate with the evaluation unit 5. In the embodiment shown, the devices for measuring current and voltage, i.e. the first device for measuring the voltage 3.1, the second device for measuring the voltage 4 and the device for measuring the current 3.2, have an analog / digital converter. Since the measured variables are recorded in analog form, they can also be processed purely in analog form. This means that the evaluation can also be carried out entirely without an analog / digital converter and without digital logic in the form of FPGAs, microcontrollers, etc.The output values ​​of all measuring devices can be analog / digital or purely analog.

[0026] The evaluation unit 5, in turn, communicates with the communication unit 6, which enables external communication. Measurement, evaluation, and communication interfaces are thus integrated into the switching device 1.

[0027] Fig. 3 shows a circuit diagram of a further embodiment of a switching device 1 according to the invention. This embodiment of the switching device 1 differs from that in Fig. 2 in that a semiconductor switch 2.2 is arranged instead of a mechanical switch, i.e., the contactor. The switching device 1 also has a first measuring device 3, which comprises a first device for measuring the voltage 3.1 and a device for measuring the current 3.2. The switch 2 is arranged in series behind it. Fig. 3, the switch is designed as a semiconductor switch 2.2. The second device for measuring the voltage 4 is arranged in series behind the semiconductor switch 2.2. The first device for measuring the voltage 3.1, the device for measuring the current 3.2 and the second device for measuring the voltage 4 communicate with the evaluation unit 5. As described above with regard to Fig. As described in Figure 2, the output values ​​of all measurement devices can be analog / digital or purely analog. The evaluation unit 5, in turn, communicates with the communication unit 6, which enables external communication. Measurement, evaluation, and communication interfaces are thus integrated into the switching device 1.

[0028] Fig. 4 shows a circuit diagram of yet another embodiment of a switching device 1 according to the invention. This embodiment of the switching device 1 differs from the Fig. 2 and Fig. 3 in that both a mechanical switch, i.e. a contactor 2.1, and a semiconductor switch 2.2 are provided. The switching device 1 in turn has a first measuring device 3, which comprises a first device for measuring the voltage 3.1 and a device for measuring the current 3.2. The contactor 2.1 and the semiconductor switch 2.2 are arranged in series behind them. The second device for measuring the voltage 4 is arranged in series behind the contactor 2.1 and the semiconductor switch 2.2. The first device for measuring the voltage 3.1, the device for measuring the current 3.2 and the second device for measuring the voltage 4 communicate with the evaluation unit 5. As described above with regard to Fig. As described in Figure 2, the output values ​​of all measurement devices can be analog / digital or purely analog. The evaluation unit 5, in turn, communicates with the communication unit 6, which enables external communication. Measurement, evaluation, and communication interfaces are thus integrated into the switching device 1.

[0029] Fig. 5 shows yet another embodiment of a switching device 1 according to the invention. In this embodiment, the concept of an intelligent switch with integrated current and voltage measurement as well as integrated evaluation is integrated into an existing contactor 2.1. The switching device 1 thus comprises a contactor 2.1 provided with busbars 7. A slot 10 is formed in at least one of the busbars 7, in which a device for measuring the current 3.2, in particular a current sensor, is arranged. The current sensor can be designed in the form of a Hall-effect-based sensor. This enables contactless measurement of the current intensity flowing through the busbar 7. The switching device 1 also has an evaluation unit 5 and a communication unit 6. Both the evaluation unit and the communication unit can be designed in digital and / or analog form.In digital form, the evaluation unit and the communication unit can include microcontrollers or programmable logic units, e.g. FPGAs.

[0030] An extension of existing or existing products can be achieved by adding the measuring devices and the evaluation and communication unit. This is exemplified in Fig. 5. Both the current sensor and the evaluation and communication units 5, 6 are located outside the housing of the contactor 2.1. Preferably, however, all components of the switching device S1 can also be integrated into a common housing.

[0031] Yet another embodiment of a switching device 1 according to the invention is shown in Fig. 6 and Fig. 7. Fig. 6 a perspective view, Fig. 7 shows a schematic representation of the switching device 1. This embodiment shows a switching device 1 with a combination of a mechanical switch, in this case a contactor 2.1, with two semiconductor switches 2.2. It is therefore a hybrid switch. Fig. Figure 6 shows the interior of the switching device 1; the common housing is not shown. The switching device 1 comprises a contactor 2.1 with a mechanical contact. The contactor 2.1 is arranged centrally in the switching device 1. The contacts of the contactor 2.1 are connected to busbars 7. This is shown in Fig. 7, the mechanical contact is shown in the open position. A current sensor or the device for measuring the current 3.2 is arranged on one of the busbars 7 (in Fig. 7 not shown). Preferably, the current sensor or the device for measuring the current 3.2 is inserted into a slot in the busbar 7 (see Fig. 6). The device for measuring the current 3.2 is then preferably designed as with respect to Fig. 5. A semiconductor module 8 is arranged on each side of the contactor 2.1. The semiconductor modules 8 each form a semiconductor switch 2.2. Each semiconductor module 8 comprises a field effect transistor, e.g. MOSFET with a control, which is arranged on a circuit board. Both semiconductor modules 8, i.e. both circuit boards, are identical except for the position of the connectors for the control. The two semiconductor modules 8 are therefore designed as identical parts. Both semiconductor modules 8 are connected to the contactor 2.1, or the busbars 7 and external connections (not shown) via suitable connection elements. In the embodiment shown, the connection elements are designed as connection blocks 9. On each side, one of these connection blocks 9 connects the respective busbar 7 with the associated semiconductor module 8. The Fig. The terminal blocks 9 shown in Figure 6 each have a solid body 11 with integrally formed press-in contacts 12. The terminal blocks 9 are plugged into the semiconductor modules 8 or into the circuit boards of the semiconductor modules 8 with the press-in contacts 12. By means of the solid bodies 11 of the terminal blocks 9, a connection to busbars is possible, for example a connection to the busbars 7, which are connected to the contacts of the contactor 2.1, or also to external connections. However, other configurations of the connection elements, i.e. the connection of the semiconductor modules to the contactor or external connections, are also possible. The devices for voltage measurement, the evaluation unit and the communication unit are in Fig. 6 and Fig. 7 are not shown, but are also components of the switching device according to the invention according to this embodiment.

[0032] Fig. Figure 8 shows a simplified circuit diagram of the switching device 1 according to the embodiment of Fig. 6 and Fig. 7, in which only the contactor 2.1 and the semiconductor modules 8 are shown. As already described, the contactor 2.1 is arranged centrally. A semiconductor module 8 is arranged on both sides of the contactor 2.1. Each semiconductor module 8 comprises a semiconductor switch 2.2, which is preferably designed as a field-effect transistor, e.g., MOSFET, and a freewheeling diode or body diode 13 arranged parallel to the semiconductor switch 2.2. The source terminals of the semiconductor switches 2.2 are connected to each other via the mechanical contact, i.e., the contactor 2.1. The current can flow bidirectionally between the two terminals, depending on the current direction via the semiconductor switch 2.2 or the corresponding freewheeling diode or body diode 13. The measuring devices for current and voltage measurement are in Fig. 7 and Fig. 8 not shown.

[0033] Fig. 9 and Fig. 10 show functions of the evaluation by means of the evaluation unit 5. General protection and monitoring functions are possible for the three variants shown, ie a switching device with a mechanical switch, a switching device with a semiconductor switch and a switching device with a mechanical switch and a semiconductor switch.

[0034] Fig. Figure 9 shows basic functions based on the measurement of the first measuring device 3 (current, measurement 1, and voltage, measurement 2), i.e., the current measuring device 3.2 and the first voltage measuring device 3.1, and the second voltage measuring device 4 (measurement 3, voltage only). General threshold-based protection is possible, with analog or digital configurations.

[0035] Based on the measured values ​​from the first current measuring device 3.2, i.e., the current sensor, an overcurrent can be detected. If the overcurrent threshold is reached, switch or switching device 1 is immediately tripped. Furthermore, the limit load integral can be calculated. The limit load integral also causes switch or switching device 1 to trip if the current exceeds the rated current over a period of time X.

[0036] As already described, a first voltage measuring device 3.2 is integrated into the first measuring device 3. The voltage is also measured using the second voltage measuring device 4. This allows the indication of overvoltage and undervoltage at terminal 1 (first voltage measuring device) and at terminal 2 (second voltage measuring device). Information is output, for example, via the communication unit 6, indicating whether the voltage is OK or not.

[0037] The current and voltage measurements at the input and output of the switch allow the condition of the switching path to be monitored. The switch resistance can be determined. For DC applications, R Schalter = |I Messung1 · (U Messung1 - U Messung2 )|. For AC applications, the complex impedance Z SchalterThis makes it possible to determine the maintenance interval or whether the switch needs to be replaced.

[0038] Using an insulation / impedance measurement, information about the insulation and impedance in the load circuit can be determined, which enables fault analysis.

[0039] Fig. Figure 10 shows further functions for evaluating the measured values ​​of the current measuring device 3.2 (Measurement 1, Current), the first voltage measuring device 3.1 (Measurement 1, Voltage), and the second voltage measuring device 4 (Voltage). The evaluation unit 5 enables analysis of the measured variables before and after the occurrence of an event (pre- and post-event error analysis). Reading out for diagnostic purposes is possible using the communication unit 6. The measured current is stored for subsequent analysis in the event of a trip or error for diagnostic purposes.

[0040] The integrated sensors, i.e., the devices for measuring current and voltage, enable arc detection. Arc detection is performed using an FFT of the current; if necessary, an additional voltage analysis is required. The current is filtered in the range of approximately 30 kHz to 100 kHz. An arc creates a Gaussian distribution in the current spectrum. The center frequency of the distribution depends on the cable lengths. List of reference symbols 1 switching device 2 switches 2.1 Contactor 2.2 Semiconductor switches 3 first measuring device 3.1 first device for measuring the voltage 3.2 Device for measuring the current 4 second device for measuring the voltage 5 Evaluation unit 6 Communication unit 7 Busbar 8 semiconductor module 9 Terminal block 10 slots 11 massive body 12 press-in contact 13 Freewheeling diode, body diode

Claims

[1] Switching device (1) comprising at least one mechanical switch (2.1) and / or semiconductor switch (2.2), at least one current measuring device (3.2) and at least one first voltage measuring device (3.1), characterized by , that at least one second device for measuring the voltage (4) is provided, wherein the first device for measuring the voltage (3.1), the at least one mechanical switch (2.1) and / or semiconductor switch (2.2) and the at least one second device for measuring the voltage (4) are connected in series. [2] Switching device (1) according to claim 1, characterized by , that the switching device (1) is designed for direct current applications. [3] Switching device (1) according to claim 1 or 2, characterized by , that the switching device (1) is bidirectional. [4] Switching device (1) according to one of the preceding claims, characterized by, that the at least one mechanical switch (2.1) and / or semiconductor switch (2.2), the current measuring device (3.2), the first voltage measuring device (3.1) and the second voltage measuring device (4) are arranged in a common housing. [5] Switching device (1) according to claim 4, further comprising an evaluation unit (5) which is arranged in the common housing. [6] Switching device (1) according to one of claims 4 or 5, further comprising a communication unit (6) arranged in the common housing. [7] Switching device (1) according to claims 1 to 6, comprising a first semiconductor module (8) with a first semiconductor switch (2.2), a mechanical switch (2.1) and a second semiconductor module (8) with a second semiconductor switch (2.2) arranged in series one behind the other, wherein the two semiconductor modules (8) are arranged anti-series. [8] Switching device (1) according to claim 7, characterized by , that the semiconductor modules (8) are designed as identical parts. [9] Switching device (1) according to claim 7 or 8 characterized by , that the semiconductor modules (8) are bidirectional. [10] Switching device (1) according to claims 7 to 9, characterized by , that each of the semiconductor modules (8) has one of the semiconductor switches (2.2) and a freewheeling diode or body diode (13) arranged in parallel thereto. [11] Switching device (1) according to at least one of the preceding claims, characterized by , that the semiconductor switches (2.2) are designed as field-effect transistors, e.g. MOSFETs. [12] Switching device (1) according to any one of claims 7 to 11, characterized by , that the source terminals of the semiconductor modules (8) are connected to each other via the at least one mechanical switch (2.1). [13] Switching device (1) according to at least one of the preceding claims, further comprising busbars (7) for contacting the at least mechanical switch (2.1) and / or the at least one semiconductor switch (2.2), wherein a receptacle is formed in at least one of the busbars (7) in which the device for measuring the current (3.2) is arranged. [14] Switching device (1) according to claim 13, characterized by , that each of the semiconductor modules (8) is connected to a busbar (7) of the mechanical switch (2.1) by means of a connection element (9) and is connected to external terminals of the switching device (1) by means of a further connection element (9). [15] Switching device (1) according to claim 13, characterized by , that the connecting elements (9) are designed as identical parts.

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