Multi-port protection device

Abstract

A multi-port protection device (10) comprises: a first DC link grid line (11); a plurality of protection switching units, each protection switching unit having a control input (60 to 63); a plurality of ports (20 to 29); and a controller (13) coupled on its output side to the control inputs (60-63) of the plurality of protection switching units. Each of the plurality of protection switching units couples a port of the plurality of ports (20 to 29) to the first DC link grid line (11).

Description

Technical Field

[0001] The present disclosure relates to a multi-port protection device. Background Art

[0002] Today, DC microgrids include storage systems (such as batteries) as prosumers, renewable energy sources (such as photovoltaic devices, wind turbines, etc.) as producers, active front ends for AC to DC and AC to AC conversion as producers, and finally AC and DC loads as consumers. All these consumers, producers, and prosumers are connected to the DC link grid line through an interface power electronic converter. There may be long cables between the interface power electronic converter and the DC link grid line. In order to protect the cables in the event of a fault event, circuit breakers and fuses are installed. Due to the low short-circuit current generating capability of the DC microgrid, solid-state circuit breakers (abbreviated as SSCB) are the fastest protection method. However, due to the high power losses and bidirectional current requirements, SSCBs are bulky and very expensive, and show relatively low efficiency.

[0003] The object is to provide a multi-port protection device with increased safety.

[0004] This object is achieved by the subject-matter of the independent claims. Further developments and embodiments are described in the dependent claims. Summary of the invention

[0005] A multi-port protection device is provided, which includes a first DC link grid line, a plurality of protection switch units, a plurality of ports and a controller. Each protection switch unit includes a control input terminal. The controller is coupled to the control input terminals of the plurality of protection switch units at its output side. Each protection switch unit in the plurality of protection switch units couples a port in the plurality of ports to the first DC link grid line.

[0006] Advantageously, the coupling of a port of the plurality of ports to the first DC link grid line may be interrupted by a protection switch unit controlled by the controller, for example in case of a fault.

[0007] In an embodiment of the multi-port protection device, the number of ports is equal to or greater than the number of protection switch units. The number of protection switch units is greater than 1 or greater than 2 or greater than 3.

[0008] In an embodiment of the multi-port protection device, the port may be an input port, an output port or an input / output port.

[0009] In an embodiment, the multi-port protection device comprises a heat sink, which is thermally coupled to each of the plurality of protection switch units. The heat sink is a common heat sink for the plurality of protection switch units. The heat sink comprises, for example, at least a fan or a cooling liquid.

[0010] In an embodiment, the multi-port protection device comprises a housing. A first DC link grid line, a plurality of protection switch units and a controller are located inside the housing.

[0011] In an embodiment of the multi-port protection device, a protection switch unit in the plurality of protection switch units is one of a DC load switch unit, a storage switch unit, a DC grid switch unit and a DC receiving switch unit. The protection switch unit is configured to provide and / or receive a DC voltage or a DC current at a port in the plurality of ports.

[0012] In an embodiment of the multi-port protection device, the DC load switch unit is configured to provide a DC voltage or a DC current at a port of the plurality of ports. The DC load switch unit comprises a first load switch. In the case of the DC load switch unit, a port of the plurality of ports is coupled to a DC load, for example via a cable, or to an external DC / AC converter. The DC / AC converter is an abbreviation for a direct current / alternating current converter. The DC / AC converter is, for example, coupled to an alternating current load (abbreviated as AC load).

[0013] In an embodiment of the multi-port protection device, the first load switch is implemented as a semi-controllable semiconductor switch. The first load switch is coupled to a port of the plurality of ports and to a first DC link grid line. The first DC link grid line may be abbreviated as a first grid line. The first load switch is a bidirectional or unidirectional switch.

[0014] In an embodiment of the multi-port protection device, the storage switch unit is configured to provide and / or receive a DC voltage or a DC current at a port of the plurality of ports. In the case of the storage switch unit, a port of the plurality of ports is for example coupled to a battery or a supercapacitor.

[0015] In an embodiment of the multi-port protection device, the storage switch unit comprises a first storage switch. The first storage switch is implemented as a semi-controllable semiconductor switch, for example. The first storage switch is coupled to a port of the plurality of ports and to the first grid line. The first storage switch is, for example, a bidirectional switch.

[0016] In an embodiment of the multi-port protection device, the DC grid switch unit is configured to provide and / or receive a DC voltage or a DC current at a port of the plurality of ports. In the case of the DC grid switch unit, a port of the plurality of ports is for example coupled to a DC grid or to an AC / DC bidirectional converter. The AC / DC bidirectional converter is for example coupled to an AC grid.

[0017] In an embodiment of the multi-port protection device, the DC grid switch unit comprises a first grid switch. The first grid switch is implemented as a semi-controllable semiconductor switch, for example. The first grid switch is coupled to a port of the plurality of ports and to a first grid line. The first grid switch is a bidirectional or unidirectional switch.

[0018] In an embodiment of the multi-port protection device, the semi-controllable semiconductor switch comprises:

[0019] - Field Effect Transistor, abbreviated as FET, or

[0020] -Anti-parallel circuit of a diode and an insulated gate bipolar transistor (abbreviated as IGBT).

[0021] In the case where the semi-controllable semiconductor switch is an anti-parallel circuit of a diode and an IGBT, the diode protects the IGBT from the reverse voltage. Since the IGBT only works in the first quadrant and cannot conduct current in the second quadrant, the protection of the IGBT is achieved. The IGBT can handle a reverse voltage of up to 20V to 30V. The IGBT can be implemented as a reverse conducting IGBT or a reverse blocking IGBT.

[0022] In an embodiment of the multi-port protection device, the FET is implemented, for example, as a metal oxide semiconductor FET (abbreviated as MOSFET), a metal insulator semiconductor FET (abbreviated as MISFET), or a high electron mobility transistor (abbreviated as HEMT). The FET includes an intrinsic body diode or reverse conduction. FETs using silicon as a substrate are generally manufactured as MOSFETs or MISFETs and have an intrinsic body diode. FETs using gallium nitride as a substrate are generally manufactured as HEMTs and have no body diode, but exhibit reverse conduction.

[0023] In the case where the semi-controllable semiconductor switch is a MOSFET, the monolithic body diode is incorporated in the MOSFET. Therefore, no additional diode is required. In addition, the MOSFET can be driven in the on-state so that the current flows through the third quadrant region. The body diode conducts only when the MOSFET is in the off-state.

[0024] In an embodiment of the multi-port protection device, the protection switch unit comprises a relay. The relay is, for example, a galvanic separation relay. The series circuit comprises the relay and a semi-controllable semiconductor switch. The series circuit is coupled to a port of the plurality of ports and is coupled to the first grid line.

[0025] In an embodiment of the multi-port protection device, the DC receiving switch unit is configured to receive a DC voltage or a DC current at a port of the plurality of ports. In the case of the DC receiving switch unit, a port of the plurality of ports is for example coupled to a photovoltaic device, a fuel cell or an AC / DC converter coupled to a wind turbine.

[0026] In an embodiment of the multi-port protection device, the DC receiving switch unit comprises a series circuit of a first diode and a first relay. The first relay is, for example, a current separation relay. The series circuit is coupled to a port of the plurality of ports and is coupled to the first grid line. Alternatively, the DC receiving switch unit comprises a series circuit of a first receiving switch and a first relay. The first receiving switch is, for example, a semi-controllable semiconductor switch.

[0027] In an embodiment of the multi-port protection device, a protection switch unit of the plurality of protection switch units comprises a current sensor, an output end of which is coupled to a controller. The controller is configured to set the protection switch unit to a non-conducting state when a current flowing through the current sensor of the protection switch unit is higher than a first threshold.

[0028] In an embodiment, the multi-port protection device has no DC / DC converter, no AC / DC converter, no AC / AC converter and no DC / AC converter.

[0029] In an embodiment, the controller comprises a communication circuit, for example configured for analog communication. The communication circuit provides communication between converters connected to the multi-port protection device.

[0030] For example, the communication circuit is configured to send at least one trigger signal to the converters.

[0031] In an embodiment, the multi-port protection device has no fully controllable semiconductor switches. Therefore, the multi-port protection device can keep the space and cost low.

[0032] In an example, the multi-port protection device is implemented as a multi-port DC link protection apparatus.

[0033] In an example, a multi-port protection device does not require fully controllable bidirectional solid-state circuit breakers for bidirectional current required for integrated battery storage and active feed AC to DC conversion. With the multi-port protection device, only semi-controllable semiconductor switches and diodes are implemented, which reduces semiconductor losses, cooling requirements and prices by approximately 50%. The multi-port protection device integrates all of these semi-controllable semiconductor switches in one device and places these switches on the same cooling medium. The power of the cooling medium is sized according to the maximum current flowing in the multi-port protection device. The semi-controllable semiconductor switches are controlled by a central controller. The central controller is also capable of communicating with power electronic converters interfaced between the DC link and consumers (loads), producers (photovoltaic devices, wind turbines, fuel cells, etc.) and prosumers (active feed converters, also known as active front ends and storage devices) through analog and / or digital communication media.

[0034] In an example, the semiconductor switch (such as a semi-controllable semiconductor switch) further comprises a local controller. If the current through the semiconductor switch reaches a predetermined limit value, the local controller is configured to turn off the semiconductor switch. The predetermined limit value may be a maximum hardware current. The local controller is, for example, an analog controller.

[0035] In an example, a multi-port DC link protection device eliminates the need for fully controllable semiconductor circuit breakers. The protection switch unit coordinates the fault event procedure inside the device and coordinates with other interface power electronic converters and / or semi-controllable semiconductor switches installed on the converter side of consumers, prosumers and producers. System volume, cost and power loss are reduced by, for example, 50%.

[0036] The following description of the drawings of the embodiments can further illustrate and explain various aspects of the multi-port protection device. Components, structures and devices having the same structure and the same effect are shown with equivalent reference symbols, respectively. As long as the components, structures and devices correspond to each other in terms of their functions in different drawings, their description will not be repeated for each of the following drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1A and Figure 1B An embodiment of an arrangement having a multi-port device and having a multi-port protection device is shown,

[0038] FIG. 2A to FIG. 2D shows an embodiment of a switch of a multi-port protection device,

[0039] FIG. 3A to FIG. 3D shows an embodiment of a protection switch unit of a multi-port protection device,

[0040] Figure 4A and Figure 4Bshows another embodiment of a multi-port protection device and apparatus,

[0041] FIG. 5A to FIG. 5E Embodiments of a multi-port protection device with a cooling device are shown in different views, and

[0042] FIG. 6A to FIG. 6D Embodiments of a multi-port protection device having a housing and a cooling device are shown in different views. DETAILED DESCRIPTION

[0043] Figure 1A An embodiment of an apparatus 1 having a multi-port device 2 is shown. The apparatus 1 is implemented as a microgrid device, for example. The multi-port device 2 comprises a first DC link grid line 11 (abbreviated as first grid line) and a second DC link grid line 12 (abbreviated as second grid line). The multi-port device 2 comprises a housing 3. The first grid line 11 and the second grid line 12 are arranged inside the housing 3.

[0044] In addition, the multi-port device 2 includes a plurality of ports 20 to 29. The ports 20 to 29 may be input ports, output ports, or input / output ports. Each of the plurality of ports 20 to 29 is coupled or connected to the first grid line 11 or the second grid line 12. Therefore, a subset of the ports 20, 22, 24, 26, 28 of the plurality of ports 20 to 29 is coupled or connected to the first grid line 11. Another subset of the ports 21, 23, 25, 27, 29 of the plurality of ports 20 to 29 is coupled or connected to the second grid line 12.

[0045] Furthermore, the device 1 comprises a plurality of cables 30 to 39. Each cable is connected to a port. Typically, the number of cables 30 to 39 is equal to the number of ports 20 to 29 or less than the number of ports 20 to 29. Figure 1A In FIG. 4 , a cable typically comprises a parasitic resistance 4 and a parasitic inductance 5 , both of which may be variable and depend on the length of the cable.

[0046] The device 1 includes a photovoltaic device 40, which is coupled to a first port 20 and a second port 21 of a plurality of ports 20 to 29. A DC / DC photovoltaic converter 45 of the device 1 couples the photovoltaic device 40 to the first port 20 and the second port 21. The DC / DC photovoltaic converter 45 can be implemented as a DC / DC converter 45, which is configured to convert a photovoltaic voltage VP provided by the photovoltaic device into a DC grid voltage VDC. The DC grid voltage VDC is tapped between a first grid line 11 and a second grid line 12. The photovoltaic device 40 includes a photovoltaic cell string or array.

[0047] In addition, the apparatus 1 includes an energy storage device 41. The energy storage device 41 is, for example, a battery or a supercapacitor. The energy storage device 41 is coupled to the third port 22 and the fourth port 23 of the plurality of ports 20 to 29. The DC / DC storage converter 46 of the apparatus 1 couples the energy storage device 41 to the third port 22 and the fourth port 23. The DC / DC storage converter 46 can be implemented as a DC / DC converter configured to convert the storage voltage VB provided by the energy storage device 41 into a DC grid voltage VDC, and vice versa.

[0048] The device 1 includes a load 42. The load 42 is implemented as a DC load, for example. The load 42 is coupled to the fifth port 24 and the sixth port 25 of the plurality of ports 20 to 29. The DC / DC converter 47 of the device 1 couples the load 42 to the fifth port 24 and the sixth port 25. The DC / DC converter 47 is configured to convert the DC grid voltage VDC into a DC power supply voltage VL supplied to the load 42.

[0049] In addition, the device 1 includes a terminal to the AC grid 43. The AC grid 43 is coupled to the seventh port 26 and the eighth port 27 of the plurality of ports 20 to 29. The AC / DC converter 48 of the device 1 couples the AC grid 43 to the seventh port 26 and the eighth port 27. The AC / DC converter 48 is implemented, for example, as a bidirectional converter or an AC / DC analog front end (abbreviated as AC / DC AFE). The active front end (abbreviated as AFE) may also be referred to as an active feed converter (abbreviated as AIC). The AC / DC converter 48 is configured to convert the DC grid voltage VDC into an AC voltage VAC supplied to the AC grid 43, and / or to convert the AC voltage VAC provided by the AC grid 43 into a DC grid voltage VDC.

[0050] The device 1 includes an additional load 44. The additional load 44 is implemented as an AC load. The additional load 44 is coupled to the ninth port 28 and the tenth port 29 of the plurality of ports 20 to 29. The device 1 includes a DC / AC converter 49, which couples the additional load 44 to the ninth port 28 and the tenth port 29. The DC / AC converter 49 is configured to convert the DC grid voltage VDC into an AC power supply voltage VLL supplied to the additional load 44.

[0051] In an alternative embodiment not shown, the device 1 comprises a fuel cell or a flywheel coupled to a first grid line 11 and a second grid line 12 similar to the photovoltaic device 40 .

[0052] Figure 1AThe device 1 shown is only an example. In another example, the device 1 includes, for example, only two or only three or only four of the group including the photovoltaic device 40, the energy storage device 41, the load 42, the AC grid 43 and the further load 44. The device 1 includes, for example, at least two or at least four of the group.

[0053] Figure 1B A further embodiment of an apparatus 1 having a multi-port protection device 10 is shown. The multi-port protection device 10 is Figure 1A The multiport protection device 10 is a further development of the multiport device 2. The multiport protection device 10 comprises a first grid line 11, a plurality of protection switch units 50 to 54 and a plurality of ports 20 to 29. Each of the plurality of protection switch units 50 to 54 couples a port of the plurality of ports 20 to 29 to the first grid line 11.

[0054] The multi-port protection device 10 includes a second grid line 12. For example, each of the plurality of protection switch units 50 to 53 couples a port of the plurality of ports 20 to 29 to the first grid line 11, and couples another port of the plurality of ports 20 to 29 to the second grid line 12. The number of ports 20 to 29 is equal to or greater than the number of protection switch units 50 to 53. The number of protection switch units 50 to 53 is greater than 1.

[0055] The protection switch unit of the plurality of protection switch units is one of the DC receiving switch unit 50, the storage switch unit 51, the DC load switch unit 52, the DC grid switch unit 53, and the additional load switch unit 54. Each protection switch unit is configured to provide and / or receive a DC voltage or a DC current at a port of the plurality of ports 20 to 29.

[0056] The DC receiving switch unit 50 connects the first port 20 and the second port 21 to the first grid line 11 and the second grid line 12. The storage switch unit 51 couples the third port 22 and the fourth port 23 to the first grid line 11 and the second grid line 12. In addition, the DC load switch unit 52 couples the fifth port 24 and the sixth port 25 to the first grid line 11 and the second grid line 12. In addition, the DC grid switch unit 53 couples the seventh port 26 and the eighth port 27 to the first grid line 11 and the second grid line 12. Correspondingly, the additional load switch unit 54 couples the ninth port 28 and the tenth port 29 to the first grid line 11 and the second grid line 12.

[0057] In the example, the device 1 comprises a DC / DC photovoltaic converter 45, a DC / DC storage converter 46, a DC / DC converter 47, an AC / DC converter 48 and a DC / AC converter 49. These converters are located outside the multi-port protection device 10. These converters 45 to 49 can be implemented as interface power electronic converters. These converters 45 to 49 are provided with fault current protection in the converters 54 to 49, because the converters 45 to 49 include controllable power electronic switches. In the event of a fault in one of the cables 30 to 39 or the first grid line 11 or the second grid line 12, the power electronic switch is immediately closed.

[0058] Figure 1B The apparatus 1 and the multi-port protection device 10 shown are only examples. In another example, the multi-port protection device 10 comprises, for example, only two or only three or only four of the group comprising a DC receiving switch unit 50, a storage switch unit 51, a DC load switch unit 52, a DC grid switch unit 53 and a further load switch unit 54. The apparatus 1 comprises, for example, at least two, at least three or at least four of the group.

[0059] like Figure 1B The multi-port protection device 10 shown is implemented as a two-wire system.

[0060] In an alternative embodiment not shown, the multi-port protection device 10 is implemented as a three-wire system. Therefore, the multi-port protection device 10 includes a third grid line. Each protection switch unit of the plurality of protection switch units 50 to 53 couples another port of the plurality of ports to the third grid line.

[0061] FIG. 2A to FIG. 2D An embodiment of a switch 70 is shown, which may be used for one or more of the above-mentioned protection switch units 50 to 54. The plurality of protection switch units comprises a DC receiving switch unit 50, a storage switch unit 51, a DC load switch unit 52, a DC grid switch unit 53 and a further load switch unit 54.

[0062] exist Figure 2A and Figure 2B , an embodiment of a semi-controllable semiconductor switch 70 is shown. The semi-controllable semiconductor switch 70 is implemented as a bidirectional switch or a semi-controllable bidirectional switch. Figure 2A As shown, the semi-controllable semiconductor switch 70 includes a diode 72 and an insulated gate bipolar transistor 71 (abbreviated as IGBT). The diode 72 and the IGBT 71 form an anti-parallel circuit. The collector of the IGBT 71 is, for example, connected to the cathode of the diode 72. The emitter of the IGBT 71 is, for example, connected to the anode of the diode 72. The IGBT 71 is an n-channel IGBT or a p-channel IGBT. The IGBT 71 is, for example, an enhancement type IGBT.

[0063] At the first node 73, the first node voltage V1 is tapped. At the second node 74, the second node voltage V2 is tapped. In the case of V1>V2, the current flows from the first node 73 to the second node 74 via the diode 72. More precisely, since the diode 72 has a forward voltage VFB, the current flows in the case of V1>V2+VFB. In the case of V1<V2, the current from the second node 74 to the first node 73 is controlled by the control signal applied to the control terminal of the IGBT 71. Therefore, in the case of applying an appropriate control signal to the IGBT 71, the current flows from the first node 73 to the second node 74 via the diode 72, and from the second node 74 to the first node 73 via the IGBT 71. Therefore, the semi-controllable semiconductor switch 70 is bidirectional.

[0064] like Figure 2B As shown, the semi-controllable semiconductor switch 70 is implemented as a field effect transistor 75 (abbreviated as FET). FET 75 includes an intrinsic body diode 76. In the case of V1>V2, the current flows from the first node 73 to the second node 74 via FET 75. FET 75 is set to an on state. FET 75 operates in the third quadrant. Alternatively, the current can flow through the intrinsic body diode 76 having a forward voltage VFB. Advantageously, the loss is lower when the current flows through FET 75 instead of flowing through the intrinsic body diode 76. In the case of V1<V2, the current from the second node 74 to the first node 73 is controlled by a control signal applied to the control terminal of FET 75.

[0065] FET 75 can be implemented, for example, as a silicon FET (abbreviated as Si FET) or a gallium nitride FET (abbreviated as GaN FET). GaN FETs generally do not contain an intrinsic body diode, but show "reverse conduction" from the first node 75 to the second node 74. FET 75 is an n-channel FET or a p-channel FET. FET 75 is, for example, an enhancement FET.

[0066] Alternatively, the semi-controllable semiconductor switch 70 includes a FET 75 and a diode 76. The FET 75 and the diode 76 form an anti-parallel circuit. The diode 76 is located outside the FET 75. Such a diode 76 can be designed so that the diode 76 has excellent characteristics compared with an intrinsic body diode.

[0067] In an alternative embodiment not shown, the semi-controllable semiconductor switch 70 includes an overvoltage protection device (abbreviated as OVP). The OVP couples the first node 73 to the second node 74. For example, the OVP couples the collector of the IGBT 71 to the emitter of the IGBT 71. Alternatively, the OVP couples the source of the FET 75 to the drain of the FET 75. Therefore, the semi-controllable semiconductor switch 70 has overvoltage protection. An example of the OVP is described below.

[0068] exist Figure 2C and Figure 2D , an embodiment of a fully controllable semiconductor switch 80 is shown. Figure 2C As shown, the fully controllable semiconductor switch 80 includes a diode 72, an IGBT 71, a further diode 82 and a further IGBT 81. The diode 72 and the IGBT 71 form an anti-parallel circuit. The further diode 82 and the further IGBT 81 form a further anti-parallel circuit. The collector of the IGBT 71 is connected to the cathode of the diode 72. The emitter of the IGBT 71 is connected to the anode of the diode 72. In the same way, the collector of the further IGBT 81 is connected to the cathode of the further diode 82. The emitter of the further IGBT 81 is connected to the anode of the further diode 82.

[0069] The anti-parallel circuit and the further anti-parallel circuit are connected in series. The further anti-parallel circuit and the anti-parallel circuit are oriented in anti-series. The emitter of the further IGBT 81 is connected to the emitter of the IGBT 71. Therefore, the anode of the further diode 82 is connected to the anode of the diode 72.

[0070] In addition, the fully controllable semiconductor switch 80 includes an overvoltage protection device 87 (abbreviated as OVP). The OVP 87 is implemented, for example, as a transient voltage suppressor diode (abbreviated as TVS diode), a varistor, a varistor, a metal oxide varistor (abbreviated as MOV), an RC snubber network or a Zener diode. The OVP 87 is connected in parallel to the series circuit of the anti-parallel circuit and the further anti-parallel circuit.

[0071] Furthermore, the fully controllable semiconductor switch 80 comprises a relay 88. The relay 88 is implemented, for example, as a galvanic separation relay (abbreviated as GSR). The relay 88 is connected in series to the anti-parallel circuit and the further anti-parallel circuit.

[0072] In an alternative embodiment not shown, the collector of the further IGBT 81 is connected to the collector of the IGBT 71. The cathode of the further diode 82 is therefore connected to the cathode of the diode 72. In this configuration, the further antiparallel circuit and the antiparallel circuit are also oriented in anti-series.

[0073] like Figure 2DAs shown, the fully controllable semiconductor switch 80 comprises a FET 75 and a further FET 85. The FET 75 comprises an intrinsic body diode 76, and the further FET 85 comprises an additional intrinsic body diode 86. The controlled part of the FET 75 and the controlled part of the further FET 85 are connected in series. The FET 75 and the further FET 85 are oriented in anti-series. Therefore, the source of the FET is connected to the source of the further FET 85. Correspondingly, the intrinsic body diode 76 and the further intrinsic body diode 86 are oriented in anti-series. The anode of the intrinsic body diode 76 is connected to the anode of the further intrinsic body diode 86. The OVP 87 is connected in parallel to the series circuit of the FET 75 and the further FET 85. The relay 88 is connected in series to the FET 75 and the further FET 85. The MOSFETs forming the FET 75 and the further FET 85 operate only in the first quadrant and the third quadrant.

[0074] In an alternative embodiment not shown, the drain of FET 75 is connected to the drain of a further FET 85. The cathode of intrinsic body diode 76 is connected to the cathode of a further intrinsic body diode 86. Also in this case, FET 75 and further FET 85 are oriented in anti-series, and intrinsic body diode 76 and further intrinsic body diode 86 are oriented in anti-series.

[0075] In order to reduce cost, heat loss and space, the multi-port protection device 10 is arranged with semi-controllable semiconductor switches 70 instead of fully controllable semiconductor switches 70 . FIG. 2A to FIG. 2D A fully controllable semiconductor switch and a semi-controllable semiconductor switch are shown.

[0076] Figure 3A An embodiment showing details of an apparatus 1 having a multi-port protection device 10 is shown. Figure 1A , Figure 1B and FIG. 2A to FIG. 2D A further development of the embodiment shown. The protection switch unit is implemented as a DC receiving switch unit 50. The DC receiving switch unit 50 is configured to receive a DC voltage or a DC current at the first port 20 and / or the second port 21. The DC receiving switch unit 50 includes a series circuit of a first diode 90 and a first relay 92. The series circuit is coupled to the first port 20 and the first grid line 11. The DC receiving switch unit 50 includes an additional series circuit of a second diode 91 and a second relay 93. The additional series circuit is coupled to the second port 21 and the second grid line 12. The first relay 92 and the second relay 93 are, for example, manufactured as a current separation relay (abbreviated as GSR). Alternatively, the first diode 90 and the second diode 91 are replaced by a first receiving switch and a second receiving switch. The first receiving switch and the second receiving switch are implemented as semi-controllable semiconductor switches 70.

[0077] The two connections between the photovoltaic device 40 and the DC / DC photovoltaic converter 45 include two fuses 96, 97. The two connections between the DC / DC photovoltaic converter 45 and the first cable 30 and the second cable 31 include two fuses 98, 99. The first cable 30 and the second cable 31 are combined in a cable shield. The cable shield is connected to the ground potential GND.

[0078] In renewable energy producers (photovoltaic, wind power, etc.), current always flows from the source to the first grid line 11. Therefore, semiconductor switches are possible, but not necessary. The semiconductor switches can be replaced by blocking diodes 90, 91. In the event of a fault in the cables 30, 31, the blocking diodes 90, 91 will block the short-circuit current flowing from the first grid line 11 and / or the second grid line 12 to the fault point. At the same time, the DC / DC photovoltaic converter 45 detects the fault by overcurrent detection and immediately shuts down the pulse width modulation (abbreviated as PWM) performed by the DC / DC photovoltaic converter 45. Once the current is cut off, the relays 92, 93 are set to the disconnected state to isolate the fault point, for example, from the rest of the DC link. Figure 3A Blocking diodes 90 , 91 are shown instead of semiconductor switches in the case of renewable energy producers such as photovoltaic installations, wind turbines.

[0079] Figure 3B An embodiment showing details of an apparatus 1 having a multi-port protection device 10 is shown. Figure 1A , Figure 1B , FIG. 2A to FIG. 2D and Figure 3A A further development of the embodiment shown. The protection switch unit is implemented as a storage switch unit 51. The storage switch unit 51 is configured to provide and / or receive a DC voltage or a DC current at the third port 22 or alternatively at another port.

[0080] The storage switch unit 51 comprises a first storage switch 100 which is implemented as a semi-controllable semiconductor switch 70, such as Figure 2A and Figure 2B As shown. The first storage switch 100 is coupled to the third port 22 and the first grid line 11. The storage switch unit 51 includes a first relay 102. The series circuit includes the first relay 102 and the first storage switch 100. The series circuit is coupled to the third port 22 and the first grid line 11.

[0081] Similarly, the storage switch unit 51 comprises a second storage switch 101 which is implemented as a semi-controllable semiconductor switch 70, such as for example Figure 2A and Figure 2BAs shown. The second storage switch 101 is coupled to the fourth port 23 and the second grid line 12. The storage switch unit 51 includes a second relay 103. The series circuit includes the second relay 103 and the second storage switch 101. The series circuit is coupled to the fourth port 23 and the second grid line 12. The first relay 102 and / or the second relay 103 are, for example, current separation relays.

[0082] like Figure 3B As shown, the first storage switch 100 and the second storage switch 101 have the same orientation towards the first grid line 11 and the second grid line 12 .

[0083] The two connections between the energy storage device 41 and the DC / DC storage converter 46 include two fuses 96, 97. The apparatus 1 includes a third storage switch 104, which is coupled to the third cable 32 and the DC / DC storage converter 46. The apparatus 1 includes a fourth storage switch 105, which is coupled to the fourth cable 33 and the DC / DC storage converter 46. The third storage switch 104 and the fourth storage switch 105 are implemented as semi-controllable semiconductor switches 70. The first storage switch 100 and the third storage switch 101 have a relative orientation towards the first grid line 11. The second storage switch 102 and the fourth storage switch 103 have a relative orientation towards the second grid line 12. The DC / DC storage converter 46 can be referred to as a battery converter.

[0084] For a battery system, there is only a semi-controllable semiconductor switch 70 on one line inside the storage switch unit 51. The current flow from the DC / DC storage converter 46 to the first grid line 11 is through the diode of the first storage switch 100. The current flow from the second grid line 12 to the DC / DC storage converter 46 is through the IGBT or MOSFET of the second storage switch 101.

[0085] In case of a cable 32, 33 fault, the DC / DC storage converter 46 detects the fault and immediately shuts down the DC / DC storage converter 46. The DC / DC storage converter 46 includes a pulse width modulation module (abbreviated as PWM module). At the same time, the IGBT or MOSFET is immediately turned off. The anti-parallel diode for the IGBT and the monolithic body diode of the MOSFET prevent the current from flowing from the DC link (such as the first grid line 11) to the fault point. In the case of a DC or other branch fault, the DC / DC storage converter 46 detects the fault and switches the PWM modulation after a certain time delay. Therefore, Figure 3B Instead of a fully controllable semiconductor switch, a semi-controllable semiconductor switch 70 is shown for storage.

[0086] Optionally, the second grid line 12 is grounded. The multi-port protection device 10 is implemented as a negative grounding device. In this case, the second storage switch 101 is optional. The second storage switch 101 is replaced by a connecting line, for example.

[0087] Figure 3C An embodiment showing details of an apparatus 1 having a multi-port protection device 10 is shown. Figure 1A , Figure 1B , FIG. 2A to FIG. 2D , Figure 3A and Figure 3B A further development of the embodiment shown. The protection switch unit is implemented as a DC load switch unit 52 . The DC load switch unit 52 is configured to provide a DC voltage or a DC current at the fifth port 24 .

[0088] The DC load switch unit 52 includes a first load switch 110. The fifth port 24 is coupled to a DC / DC converter 47, a DC / AC converter (such as a DC / AC converter 49) or directly to a DC load, for example, via a cable 34. The DC / AC converter is coupled to an AC load, for example. The first load switch 110 is implemented as a semi-controllable semiconductor switch 70 and is coupled to the fifth port 24 and to the first grid line 11. The DC load switch unit 52 includes a first load relay 112. The series circuit includes the first load relay 112 and the first load switch 110. The series circuit is coupled to the fifth port 24 and the first grid line 11.

[0089] The DC load switch unit 52 includes a second load switch 111. The sixth port 25 is coupled to a DC / DC converter 47, a DC / AC converter (such as a DC / AC converter 49) or directly to a DC load, for example, via a cable 35. The second load switch 111 is implemented as a semi-controllable semiconductor switch 70 and is coupled to the sixth port 25 and to the second grid line 12. The DC load switch unit 52 includes a second load relay 113. The series circuit includes the second load relay 113 and the second load switch 111. The series circuit is coupled to the sixth port 25 and the second grid line 12. The first load relay 112 and / or the second load relay 113 are, for example, current separation relays.

[0090] like Figure 3C As shown, the first load switch 110 and the second load switch 111 have the same orientation towards the first grid line 11 and the second grid line 12 .

[0091] In the case of the DC / DC converter 47, the current flow from the first grid line 11 and the second grid line 12 to the DC / DC converter 47 is through the IGBT. The anti-parallel diode is configured to protect the IGBT from a reverse voltage applied from the emitter to the collector. In the event of a load 42 failure, the DC / DC converter 47 or the DC / AC converter 49 detects the failure and immediately cuts off the current.

[0092] Alternatively, the load 42 (for example, implemented as a DC load) is directly connected to the fifth port 24 and the sixth port 25 via the cables 34, 35 (but without the DC / DC converter 47). The DC / DC converter 47 is implemented as an interface converter. The DC / DC converter 47 includes, for example, an overcurrent (abbreviated as OC) protection function and / or a short circuit (abbreviated as SC) protection function.

[0093] In alternative embodiments (such as Figure 4A ), the DC load switch unit 52 includes a first OVD 126 connected to a terminal of the first load switch 110. The DC load switch unit 52 includes a second OVD 127 connected to a terminal of the second load switch 111.

[0094] Figure 3D An embodiment showing details of an apparatus 1 having a multi-port protection device 10 is shown. Figure 1A , Figure 1B , FIG. 2A to FIG. 2D as well as FIG. 3A to FIG. 3C A further development of the embodiment shown. The protection switch unit is implemented as a DC grid switch unit 53. The DC grid switch unit 53 is configured to provide and / or receive a DC voltage or a DC current at the seventh port 26 and the eighth port 27.

[0095] The DC grid switch unit 53 includes a first grid switch 114. The first grid switch 114 is coupled to the seventh port 26 and the first grid line 11. The seventh port 26 is coupled to the AC / DC converter 48, for example via the cable 36. The AC / DC converter 48 is coupled to the AC grid 43, for example. The first grid switch 114 is implemented as a semi-controllable semiconductor switch 70. The DC load switch unit 52 includes a first grid relay 116. The series circuit includes the first grid relay 116 and the first grid switch 114. The series circuit is coupled to the seventh port 26 and the first grid line 11. The first grid relay 116 is, for example, a galvanic separation relay.

[0096] The DC grid switch unit 53 includes a second grid switch 115. The eighth port 27 is coupled to the AC / DC converter 48, for example, via a cable 37. The second grid switch 115 is implemented as a semi-controllable semiconductor switch 70. The second grid switch 115 is coupled to the eighth port 27 and the second grid line 12. The DC grid switch unit 53 includes a second grid relay 117. The second grid relay 117 is, for example, a current separation relay. The series circuit includes the second grid relay 117 and the second grid switch 115. The series circuit is coupled to the eighth port 27 and the second grid line 12.

[0097] like Figure 3D As shown, the first grid switch 114 and the second load switch 115 have the same orientation towards the first grid line 11 and the second grid line 12 .

[0098] The device 1 comprises a third grid switch 118, which is coupled to the cable 36 and the AC / DC converter 48. The device 1 comprises a fourth grid switch 119, which is coupled to the cable 37 and the AC / DC converter 48. The third grid switch 118 and the fourth grid switch 119 are implemented as semi-controllable semiconductor switches 70. The first grid switch 114 and the third grid switch 118 have a relative orientation towards the first grid line 11. The second grid switch 115 and the fourth grid switch 119 have a relative orientation towards the second grid line 12.

[0099] The AC to DC conversion is done by an active fed converter, also known as an active front end (abbreviated as AFE). The current flow can be from the AC side to the first grid line 11 and the second grid line 12, or vice versa. The current flow from the AC side to the DC link is through the IGBT, and vice versa through the diode. In the event of a fault in the grid lines 11, 12, the IGBT is immediately turned off. In the event of a fault in the cables 36, 37 placed between the first grid line 11 and the second grid line 12 and the AC / DC converter 48, the third grid switch 118 and the fourth grid switch 119 are set to a non-conducting state so that the rest of the DC grid can still provide power to the loads 42, 44. Optionally, in the event of a fault in the cables 36, 37, the first grid switch 114 and the second grid switch 115 are also set to a non-conducting state. The DC grid switch unit 53 can be referred to as a solid state circuit breaker (abbreviated as SSCB).

[0100] Figure 4AA further embodiment of a multi-port protection device 10 is shown, which is a further development of the above-mentioned embodiment. The multi-port protection device 10 comprises a controller 13. Each protection switch unit 50 to 54 comprises a control input 60 to 63. The controller 13 has at least one output coupled to the control inputs 60 to 63 of the plurality of protection switch units 50 to 53. The controller 13 is implemented, for example, as a microcontroller, a microprocessor, a state machine and / or a device of logic gates. The controller 13 comprises, for example, a power supply. The control inputs 60 to 63 are coupled to the control terminals of each switch.

[0101] The storage switch unit 51 includes a first OVP 124 connected to a terminal of the first storage switch 100. The storage switch unit 51 includes a second OVP 125 connected to a terminal of the second storage switch 101. In addition, the DC load switch unit 52 includes a first OVP 126 connected to a terminal of the first load switch 110. The DC load switch unit 52 includes a second OVP 127 connected to a terminal of the second load switch 111. In addition, the DC grid switch unit 53 includes a first OVD 128 connected to a terminal of the first grid switch 114. The DC grid switch unit 53 includes a second OVD 129 connected to a terminal of the second grid switch 115. The OVDs 124 to 129 may be implemented as, for example, OVD 87.

[0102] Furthermore, the multi-port protection device 10 incorporates a plurality of communication ports 120 to 123 connected to the controller 13. The communication ports 120 to 123 are configured for analog or digital communication with the converters 45 to 49 (shown above).

[0103] The multi-port protection device 10 includes, for example, at least one voltage measurement circuit 130 to 132. At least one voltage measurement circuit 130 to 132 is coupled to at least one input terminal of the controller 13. The first voltage measurement circuit 130 is connected to the first grid line 11 and the second grid line 12. The first voltage measurement circuit 130 is configured to measure a DC grid voltage VDC. The DC grid voltage VDC is provided between the first grid line 11 and the second grid line 12. The second voltage measurement circuit 131 is configured to measure a voltage between the first grid line 11 and the ground potential GND. The third voltage measurement circuit 132 is configured to measure a voltage between the second grid line 12 and the ground potential GND.

[0104] The multi-port protection device 10 comprises an overvoltage protection device 135 (abbreviated as OVD). The OVD 135 is implemented, for example, as a multi-quantum well diode (abbreviated as MOV diode), a transient voltage suppression diode (abbreviated as TVS diode), a varistor, a varistor or a Zener diode. The OVP 135 couples the first grid line 11 to the second grid line 12. Optionally, the multi-port protection device 10 is combined with an additional OVP 136 that couples the first grid line 11 to the second grid line 12.

[0105] In addition, the multi-port protection device 10 includes an arc extinguishing circuit (crowbar circuit) 139. The arc extinguishing circuit 139 includes a discharge switch 137 and a discharge load 138. The discharge switch 137 is manufactured as a semi-controllable semiconductor switch 70. The diode or intrinsic diode of the discharge switch 137 has an anode coupled to the second grid line 12 and a cathode coupled to the first grid line 11. Therefore, in the case where the voltage at the first grid line 11 is higher than the voltage at the second grid line 12, the diode is blocked. In the case where the voltage at the first grid line 11 is lower than the voltage at the second grid line 12, the diode is turned on. The discharge load 138 is implemented as a resistor, for example. The arc extinguishing circuit 139 is configured to limit the continuous overvoltage of the DC grid voltage VDC. The arc extinguishing circuit 139 is controlled by the controller 13. The arc extinguishing circuit 139 is also configured to discharge the first grid line 11 and the second grid line 12 in the case of maintenance work.

[0106] The plurality of protection switch units 50 to 54 include current sensors 140 to 147. Typically, each of the plurality of protection switch units 50 to 54 includes at least one of the current sensors 140 to 147. The current sensors 140 to 147 are coupled to at least one input terminal of the controller 13.

[0107] The first fuse 148 is arranged between the seventh port 26 and the first grid switch 114 . The second fuse 149 is arranged between the eighth port 27 and the second grid switch 115 .

[0108] The multi-port protection device 10 has no DC / DC converter, no AC / DC converter, no AC / AC converter and no DC / AC converter. The multi-port protection device 10 has no fully controllable bidirectional semiconductor switches.

[0109] The multi-port protection device places all semi-bidirectional and unidirectional switches and diodes in a single device. Each power line includes a current separation relay and a current measurement unit. The DC link is protected by overvoltage protection devices 135, 136. The controller 13 is implemented as a central microcontroller unit, for example. The controller 13 is used for measurement and control purposes. The controller 13 is also configured to communicate with the interface power electronic converters 45 to 49 by means of digital and / or analog signals. For normal switch on and off and fault conditions, the controller 13 sends a trip signal to the interface converters 45 to 49. The multi-port protection device 10 also performs voltage measurements in the DC link and from the DC link to the ground GND so as to detect faults also by voltage measurements.

[0110] In an alternative embodiment not shown, the multi-port protection device 10 comprises at least one further voltage measurement circuit. At least one further voltage measurement circuit is coupled or connected to a port of the plurality of ports 20 to 29. At least one further voltage measurement circuit is coupled or connected to each port of the plurality of ports 20 to 29, for example.

[0111] In an alternative embodiment not shown, the multi-port protection device 10 comprises at least one additional OVD at a port of the plurality of ports 20 to 29. In the example, the at least one additional OVP couples the first port 20 to the second port 21, the third port 22 to the fourth port 23, the fifth port 24 to the sixth port 25, the seventh port 26 to the eighth port 27 and / or the ninth port 28 to the tenth port 29. Thus, there is also an OVP at the terminal exterior.

[0112] Figure 4B A further embodiment of an apparatus 1 with a multi-port protection device 10 is shown, which is a further development of the above-described embodiment. The apparatus 1 comprises a further multi-port protection device 15. The first grid line 11 and the second grid line 12 of the multi-port protection device 10 are directly connected or coupled to the first grid line 11' and the first grid line 12' of the further multi-port protection device 15. Thus, the further multi-port protection device 15 and the multi-port protection device 10 can be connected together on the same DC link. Figure 4B As shown, the further multi-port protection device 15 is identical to the multi-port protection device 10 .

[0113] Alternatively, the further multi-port protection device 15 and the multi-port protection device 10 are different. The further multi-port protection device 15 and the multi-port protection device 10 comprise, for example, different selections of the protection switch units 50 to 54 .

[0114] As indicated by the points, the arrangement 1 optionally comprises one or more additional multi-port protection devices having a first grid line and a second grid line connected to the first grid line 11 and the second grid line 12 of the multi-port protection device 10. Thus, more than one or more than two multi-port protection devices 10, 15 may be connected on the same DC link.

[0115] FIG. 5A to FIG. 5E In different figures, an embodiment of a multi-port protection device 10 is shown, which is a further development of the above-mentioned embodiment. The multi-port protection device 10 comprises a cooling device. The multi-port protection device 10 comprises a heat sink 152, which is thermally coupled to each of the plurality of protection switch units 50 to 53. The heat sink 152 comprises at least one fan. FIG. 5A to FIG. 5E In the example shown, six fans are used.

[0116] In an alternative embodiment not shown, the heat sink 152 is cooled using liquid. Heat is transferred away from the heat sink 152 via the liquid.

[0117] FIG. 6A to FIG. 6D In different figures, an embodiment of a multi-port protection device 10 is shown, which is a further development of the above-mentioned embodiment. The multi-port protection device 10 comprises a housing 3. A plurality of protection switch units 50 to 53, a first grid line 11 and a second grid line 12 and a controller 13 are located inside the housing 3. The housing 3 is made of a polymer or a metal. The housing 3 has at least one opening for an airflow driven by at least one fan. The housing 3 has at least one further opening for cables 30 to 37.

[0118] The multi-port protection device 10 places all solid-state semiconductor switches on the same cooling medium, such as a heat sink or cold plate. The main purpose of the DC link is to provide the power requirements of the loads 42 , 44 .

[0119] In the case where the AC voltage VAC is not available, the power demand is supplied from the battery of the energy storage device 41, or if the photovoltaic voltage VP of the photovoltaic device 40 is available, the power demand is supplied from both the battery and the photovoltaic device 40. In the case where the AC voltage VAC is available and there is a load demand but the battery is discharged, the active front end first provides the power demand of the loads 43 and 44. During this period, the photovoltaic voltage VP can provide the full power demand of the loads 42 and 44 if the photovoltaic voltage VP is also available. The loads 42 and 44 can also be shared between the photovoltaic voltage VP and the active front end. In other words, the current that will circulate in the first grid line 11 and the second grid line 12 will always be equal to the nominal current demand of the loads 42 and 44. Since the current demand will only come from one source or a combination of all sources, there is no need to determine the size of the cooling medium power for a single source. Taking into account the maximum load current, the cooling medium will be significantly reduced when the power semiconductor switch is placed on a single common cooling system. The housing can be constructed as a heat sink or a cold plate.

[0120] The multi-port protection device 10 can also trip a semi-controllable semiconductor switch 70 placed just after the battery converter 46. In the event of a double fault, where a semiconductor switch fails in the converter, the semi-controllable semiconductor switch can shut down the current. With this configuration, the need for fuses is eliminated by distributing the fully controllable semiconductor switch in two separate semi-controllable semiconductor switches. In addition, the multi-port protection device 10 is optionally configured to coordinate fault events with other multi-port protection devices or multi-port DC link protection devices installed in different locations.

[0121] like FIG. 1A to FIG. 6D The illustrated embodiments represent examples of the improved multi-port protection device, but they do not constitute a complete list of all embodiments according to the improved multi-port protection device. For example, the actual multi-port protection device may differ from the illustrated embodiments in terms of components, structure and shape.

[0122] Reference Mark

[0123]

Claims

1. A multi-port protection device (10), comprising: - a first DC link grid line (11), - a plurality of protection switch units, each protection switch unit having a control input (60 to 63), - Multiple ports (20 to 29), and a controller (13) coupled at its output side to the control inputs (60 to 63) of the plurality of protection switch units, Each of the plurality of protection switch units couples a port of the plurality of ports (20 to 29) to the first DC link grid line (11).

2. The multi-port protection device (10) according to claim 1, wherein: The number of ports (20 to 29) is equal to or greater than the number of protection switch units, and wherein the number of protection switch units is greater than one.

3. The multi-port protection device (10) according to claim 1 or 2, wherein: The multi-port protection device (10) includes a heat sink (152) thermally coupled to each protection switch unit of the plurality of protection switch units.

4. The multi-port protection device (10) according to one of claims 1 to 3, in, The multi-port protection device (10) comprises a housing (3), and The first DC link grid line (11), the plurality of protection switch units and the controller (13) are located inside the housing (3).

5. The multi-port protection device (10) according to one of claims 1 to 4, in, The protection switch unit of the plurality of protection switch units is one of a DC receiving switch unit (50), a storage switch unit (51), a DC load switch unit (52), a DC grid switch unit (53), and another load switch unit (54), and Each of the plurality of protection switch units is configured to provide and / or receive a DC voltage or a DC current at a port among the plurality of ports (20 to 29).

6. The multi-port protection device (10) according to claim 5, wherein: The DC load switch unit (52) is configured to provide a DC voltage or a DC current at a port (24) among the plurality of ports (20 to 29), and the DC load switch unit (52) includes a first load switch (110).

7. The multi-port protection device (10) according to claim 6, wherein: The first load switch (110) is implemented as a semi-controllable semiconductor switch (70) and is coupled to the port (24) of the plurality of ports (20 to 29) and to the first DC link grid line (11).

8. The multi-port protection device (10) according to claim 5, wherein: The storage switch unit (51) is configured to provide and / or receive a DC voltage or a DC current at a port (22) among the plurality of ports (20 to 29).

9. The multi-port protection device (10) according to claim 8, wherein: The storage switch unit (51) comprises a first storage switch (100) which is implemented as a semi-controllable semiconductor switch (70) and is coupled to the port (22) of the plurality of ports (20 to 29) and to the first DC link grid line (11).

10. The multi-port protection device (10) according to claim 5, wherein: The DC grid switch unit (53) is configured to provide and / or receive a DC voltage or a DC current at a port (26) among the plurality of ports (20 to 29).

11. The multi-port protection device (10) according to claim 10, wherein: The DC grid switch unit (53) comprises a first grid switch (114) which is implemented as a semi-controllable semiconductor switch (70) and is coupled to the port (26) of the plurality of ports (20 to 29) and to the first DC link grid line (11).

12. The multi-port protection device (10) according to one of claims 7, 9 or 11, in, The semi-controllable semiconductor switch (70) comprises: - a field effect transistor (75), or -An anti-parallel circuit of a diode (72) and an insulated gate bipolar transistor (71).

13. The multi-port protection device (10) according to one of claims 7, 9, 11 or 12, in, The protection switch unit includes relays (88, 102, 112, 116), wherein the series circuit comprises the relay (88, 102, 112, 116) and the semi-controllable semiconductor switch (70), and wherein the series circuit is coupled to a port (22, 24, 26) of the plurality of ports (20 to 29) and to the first DC link grid line (11).

14. The multi-port protection device (10) according to claim 5, wherein: The DC receiving switch unit (50) is configured to receive a DC voltage or a DC current at a port (20) among the plurality of ports (20 to 29).

15. The multi-port protection device (10) according to claim 14, wherein: The DC receiving switch unit (50) comprises a series circuit of a first diode (90) and a first relay (88, 92), and wherein the series circuit is coupled to the port (20) of the plurality of ports (20 to 29) and to the first DC link grid line (11).

16. Multi-port protection device (10) according to one of claims 1 to 15, in, A protection switch unit among the plurality of protection switch units comprises a current sensor (140 to 147), an output end of the current sensor being coupled to the controller (13), and wherein the controller (13) is configured to set the protection switch unit to a non-conducting state when a current flowing through the current sensor (140 to 147) is higher than a first threshold value.

17. The multi-port protection device (10) according to one of claims 1 to 16, in, The multi-port protection device (10) has no DC / DC converter, no AC / DC converter, no AC / AC converter and no DC / AC converter.

18. Multi-port protection device (10) according to one of claims 1 to 17, in, The multi-port protection device (10) has no fully controllable semiconductor switches (80).

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