Power conversion device

Abstract

The embodiment of the invention provides a power conversion device. The power conversion device includes: a power conversion circuit connected to a bus; the bus comprises a direct current bus and / or an alternating current bus; the current protection unit is arranged in at least one bus; wherein the current protection unit comprises a current detection device and an excitation fuse which are connected in series, the current detection device is used for detecting current in the bus, and the excitation fuse is used for cutting off the current in the bus. The current protection unit formed by the excitation fuse and the current detection device is integrated with the power conversion circuit to form the power conversion device, so that the applicability of the power conversion device to different circuit protection requirements can be improved to a certain extent.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of electrical engineering, and specifically to a power conversion device. Background Art

[0002] Renewable energy power generation systems or energy storage systems have made significant progress and been widely used in recent years.

[0003] However, in some cases, short-circuit current or overcurrent may be generated in the renewable energy power generation system or the energy storage system, thereby causing damage to components in the renewable energy power generation system or the energy storage system.

[0004] To this end, in the prior art, fuses are provided in renewable energy power generation systems or energy storage systems to reduce the risk of components being damaged when short circuit current or overcurrent occurs.

[0005] However, designers or other engineers of renewable energy power generation systems or energy storage systems need to spend a lot of time and energy when selecting appropriate fuses. Summary of the invention

[0006] Multiple embodiments in this specification provide a power conversion device that has high applicability to different protection requirements of energy systems such as renewable energy power generation systems or energy storage systems.

[0007] An embodiment of the present specification provides a power conversion device, which includes: a power conversion circuit connected to a bus; the bus includes a DC bus and / or an AC bus; a current protection unit is arranged in at least one bus; wherein the current protection unit includes a current detection device and an excitation fuse connected in series; wherein the current detection device is used to detect the current value of the bus, and the excitation fuse is used to cut off the current in the bus.

[0008] In some embodiments, the power conversion device further includes a controller connected to the excitation fuse and the current detection device.

[0009] In some embodiments, the excitation fuse has an excitation signal input terminal, the power conversion device also includes a power supply unit, and the current protection unit also includes a switch unit connected between the excitation signal input terminal and the power supply unit, and the switch unit is controlled by the controller.

[0010] In some embodiments, the DC bus includes a DC positive bus and a DC negative bus; at least one of the DC positive bus and the DC negative bus is provided with the current protection unit; or, at least one of the DC positive bus and the DC negative bus is provided with the current protection unit and a basic fuse.

[0011] In some embodiments, a DC bus that is not provided with the current protection unit is provided with a basic fuse.

[0012] In some embodiments, the DC bus includes a DC positive bus and a DC negative bus; the DC positive bus and the DC negative bus are respectively provided with the current protection unit and share the same controller.

[0013] In some embodiments, the AC bus includes an AC A-phase bus, an AC B-phase bus and an AC C-phase bus; at least one of the AC A-phase bus, the AC B-phase bus and the AC C-phase bus is provided with the current protection unit; or, at least one of the AC A-phase bus, the AC B-phase bus and the AC C-phase bus is provided with the current protection unit and a basic fuse.

[0014] In some embodiments, the AC busbar that is not provided with the current protection unit is provided with a basic fuse.

[0015] In some embodiments, the AC bus includes an AC A-phase bus, an AC B-phase bus and an AC C-phase bus; at least two of the AC A-phase bus, the AC B-phase bus and the AC C-phase bus are respectively provided with the current protection unit and share the same controller.

[0016] In some embodiments, the fusing current strength of the base fuse is less than the fusing current strength of the excitation fuse.

[0017] In the multiple embodiments provided in this specification, the power conversion device may include a power conversion circuit and a current protection unit. Among them, the current protection unit may include a current detection device and an excitation fuse connected in series. The power conversion circuit may be connected to a bus. The bus may include a DC bus and / or an AC bus. The current protection unit may be arranged in any bus. Therefore, according to the different protection requirements of different energy systems, when the current detection device detects that the bus current provided with the current protection unit is large, the excitation fuse may respond to the protection requirements of the energy system and fuse to disconnect the current. Thus, it can be applicable to energy systems such as renewable energy power generation systems or energy storage systems with different protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments in this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments in this specification. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0019] Figure 1 A schematic diagram of the topological structure of a power conversion device with a current protection unit provided on a DC bus is provided for one embodiment of the present specification.

[0020] Figure 2 A schematic diagram of the topological structure of a power conversion device with a current protection unit provided on a DC bus is provided for one embodiment of the present specification.

[0021] Figure 3 A schematic diagram of the topological structure of a power conversion device in which an AC bus is provided with a current protection unit is provided for one embodiment of the present specification.

[0022] Figure 4 A schematic diagram of the topological structure of a power conversion device in which an AC bus is provided with a current protection unit is provided for one embodiment of the present specification.

[0023] Figure 5 A schematic diagram of the topological structure of a power conversion device in which a DC bus and an AC bus are provided with a current protection unit is provided for one embodiment of the present specification.

[0024] Figure 6 A schematic diagram of the topological structure of a power conversion device provided with an energy conversion module is provided for one embodiment of the present specification.

[0025] Figure 7 A schematic diagram of the topological structure of a power conversion device provided in which a DC bus is provided with a current protection unit and a basic fuse according to an embodiment of the present specification.

[0026] Figure 8 A schematic diagram of the topological structure of a power conversion device in which an AC bus is provided with a current protection unit is provided for one embodiment of the present specification.

[0027] Fig. 9 A schematic diagram of the topological structure of a power conversion device provided in an embodiment of the present specification, in which a DC bus and an AC bus are provided with a current protection unit and a basic fuse.

[0028] Fig.10 A schematic diagram of the topological structure of a power conversion device provided in an embodiment of the present specification, in which a busbar without a current protection unit is provided with a basic fuse.

[0029] Fig.11 A schematic diagram of the topological structure of a power conversion device provided in an embodiment of the present specification, in which a busbar without a current protection unit is provided with a basic fuse.

[0030] Fig.12 A schematic diagram of the operation process of a power conversion device provided for one embodiment of the present specification.

[0031] Fig.13 A schematic diagram of a topological structure of a power conversion circuit of a converter provided in accordance with an embodiment of the present specification.

[0032] Fig.14 A schematic diagram of a topological structure of a power conversion circuit of an inverter provided for one embodiment of the present specification.

[0033] Figure numerals: 1, power conversion device; 10, converter; 20, inverter; 100, power conversion circuit; 101, DC switch; 102, voltage stabilizing circuit; 103, electric energy conversion circuit; 104, filtering circuit; 105, AC switch; 110, DC bus; 112, DC positive bus; 114, DC negative bus; 120, AC bus; 122, A phase bus; 124, B phase bus; 126, C phase bus; 130, current protection unit; 132, current detection device; 134, excitation fuse; 136, switch unit; 140, controller; 150, power supply unit; 160, basic fuse; 170, energy conversion module. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0035] In the description of the embodiments of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0036] For some renewable energy power generation systems or energy storage systems, due to different topological structures or different parameters of components used, the current values ​​of short-circuit currents appearing in these renewable energy power generation systems or energy storage systems may be different.

[0037] In order to reduce the risk of damage to components when short-circuit current occurs in renewable energy power generation systems or energy storage systems to a certain extent, designers or other engineers of renewable energy power generation systems or energy storage systems need to pre-calculate the current value of short-circuit current that may occur in renewable energy power generation systems or energy storage systems based on the circuit characteristics such as the topology of each system and component parameters. Furthermore, designers or other engineers can determine the specifications of fuses applicable to each system based on the pre-calculated short-circuit current value, and purchase and install applicable fuses in the corresponding renewable energy power generation systems or energy storage systems.

[0038] However, when the topology or component parameters of a renewable energy power generation system or energy storage system change, designers or other engineers need to recalculate the current value of the short-circuit current that may occur and replace the corresponding fuse. For example, when the battery type of the battery pack in the energy storage system is changed, the current value of the short-circuit current that may occur in the energy storage system may also change. At this time, designers or other engineers need to recalculate the current value of the short-circuit current and replace the fuse with a corresponding specification. This increases the workload of designers to a certain extent, and also reduces the operating efficiency of the renewable energy power generation system or energy storage system to a certain extent.

[0039] In order to solve the above technical problems, a circuit protection device that can adapt to different current values ​​can be added to the renewable energy power generation system or energy storage system. Specifically, the circuit protection device may include a current detection device and an excitation fuse connected in series. Thus, when faced with different circuit protection requirements, the current value of the circuit in the renewable energy power generation system or energy storage system can be monitored by the current detection device, and when the current value exceeds the set threshold, the excitation fuse is controlled to melt, so as to reduce the risk of damage to components.

[0040] However, adding circuit protection equipment may increase the circuit design difficulty for designers of renewable energy power generation systems or energy storage systems to a certain extent, and may also increase the workload of maintenance personnel to a certain extent.

[0041] Considering that the power conversion device is a key component of the energy storage system or the renewable energy power generation system, and the short-circuit current is more likely to appear in the busbar of the power conversion device or the line connected to the busbar. For this reason, a power conversion device that can realize the function of a current protection device is proposed in the embodiment of this specification. Among them, a current protection unit is integrated in the power conversion device. The current protection unit can be set at any busbar of the power conversion device to realize the function of the current protection device.

[0042] By integrating the current protection unit with the power converter, the complexity of external wiring can be reduced to a certain extent, and the compactness and reliability of the system as a whole can be enhanced, which is conducive to simplifying the equipment layout and reducing the risk of failure caused by wiring errors. In addition, when the power conversion device in the embodiment of this specification is used to design an energy storage system or a renewable energy power generation system, the design difficulty of the designer will not be greatly increased.

[0043] In some embodiments, the current protection unit can be used to replace the traditional fuse provided in the power conversion device in the related art. Therefore, after the fuse in the power conversion device provided in the embodiment of this specification is blown, the maintenance personnel perform the steps of replacing the fuse, which is roughly similar to the steps of replacing the fuse in the power conversion device in the related art, which is also more friendly to the maintenance personnel.

[0044] See also Figure 1 One embodiment of the present specification provides a power conversion device 1. The power conversion device 1 includes a power conversion circuit 100, a DC bus 110, an AC bus 120, a current protection unit 130, a controller 140 and a power supply unit 150.

[0045] The power conversion circuit 100 is used to convert the form of electric energy. For example, the power conversion circuit 100 can realize the conversion between direct current and alternating current through the switch control of power electronic devices (such as IGBT, MOSFET, etc.). Alternatively, the power conversion circuit 100 can also realize the conversion between direct current and direct current. The embodiments of this specification are not specifically limited here.

[0046] The power conversion circuit 100 is connected to the bus. The bus is a trunk line for collecting or distributing electric energy. Specifically, the bus may include a DC bus 110 and an AC bus 120. Of course, the bus may also include only one of the DC bus 110 or the AC bus 120. For example, when the power conversion circuit 100 is used to realize the conversion between DC power and DC power, the bus may only include the DC bus 110.

[0047] The DC bus 110 is a main line for collecting or distributing DC power and includes a DC positive bus 112 and a DC negative bus 114 .

[0048] The AC bus 120 is a trunk line for collecting or distributing AC power. Taking three-phase power as an example, the AC bus 120 includes an AC A-phase bus 122 , an AC B-phase bus 124 , and an AC C-phase bus 126 .

[0049] The current protection unit 130 is used to protect the components in the power conversion circuit 100 and reduce the risk of damage to the components due to overcurrent or short-circuit current. Specifically, when the current protection unit 130 detects abnormal current (such as overcurrent or short circuit) in the bus, it can cut off the current path to protect the components in the circuit from being damaged or reduce the risk of damage to the components in the circuit.

[0050] Specifically, the current protection unit 130 includes a current detection device 132 and an excitation fuse 134 connected in series. The current detection device 132 is used to monitor the magnitude of the current in the busbar in real time. For example, the current detection device 132 can be a Hall current sensor. Of course, the current detection device 132 can also be an eddy current sensor. The embodiments of this specification are not specifically limited here.

[0051] The excitation fuse 134 is a type of fuse. The excitation fuse 134 is used to cut off the current when the current value in the busbar in which it is located exceeds a specified threshold. Specifically, the excitation fuse 134 is provided with an electronic control element, which can activate the fusing mechanism of the excitation fuse through electronic control means, thereby disconnecting the circuit, so as to reduce the risk of damage to components caused by excessive short-circuit current to a certain extent.

[0052] In this embodiment, the excitation fuse 134 may be an active excitation fuse 134 or a passive excitation fuse 134. This embodiment of the specification does not specifically limit this.

[0053] By connecting the excitation fuse 134 and the current detection device 132 in series, the current flowing through the excitation fuse 134 can be detected in real time by the current detection device 132. That is, the current detection device 132 can detect the current in the circuit to be protected in real time. When the current flowing through the current detection device 132 and the excitation fuse 134 connected in series is greater than the specified threshold, the controller 140 can activate the fusing mechanism of the excitation fuse 134 to cut off the current of the circuit where the excitation fuse 134 is located. It can be seen that the fusing of the excitation fuse 134 no longer depends on its own properties, but is blown according to the control strategy of the controller 140. Therefore, the current detection device 132 and the excitation fuse 134 are arranged in series in the circuit to be protected, which can realize full-range protection of the current, has high applicability for different circuit protection requirements, and is easy to transplant to other devices.

[0054] In the current protection unit 130 , the excitation fuse 134 and the current detection device 132 may be disposed on any one busbar or any plurality of busbars.

[0055] For example, see Figure 1The DC positive bus 112 and the DC negative bus 114 are both provided with an excitation fuse 134 and a current detection device 132 connected in series. Alternatively, please refer to Figure 2 The DC positive bus 112 is provided with an excitation fuse 134 and a current detection device 132 connected in series. The DC negative bus 114 is not provided with an excitation fuse 134 and a current detection device 132 connected in series.

[0056] Alternatively, see Figure 3 The AC A-phase busbar 122, the AC B-phase busbar 124 and the AC C-phase busbar 126 are all provided with an excitation fuse 134 and a current detection device 132 connected in series. Alternatively, please refer to Figure 4 The AC A-phase busbar 122 is provided with an excitation fuse 134 and a current detection device 132 connected in series. The AC B-phase busbar 124 and the AC C-phase busbar 126 are not provided with an excitation fuse 134 and a current detection device 132 connected in series.

[0057] In some embodiments, see Figure 5 The AC A-phase busbar 122, the AC B-phase busbar 124, and the AC C-phase busbar 126 may all be provided with an excitation fuse 134 and a current detection device 132 connected in series. The DC positive busbar 112 and the DC negative busbar 114 may only be provided with an excitation fuse 134 and a current detection device 132 connected in series. Specifically, Figure 5 In the figure, the DC positive bus 114 is provided with an excitation fuse 134 and a current detection device 132 as an example. The power supply unit 150 is used to provide power to the current protection unit 130. Specifically, the power supply unit 150 can be an uninterruptible power supply system (UPS). Of course, the power supply unit 150 can also be a battery pack in an energy storage system or a renewable energy power generation device in a renewable energy power generation system. This embodiment is not specifically limited here.

[0058] In some cases, the excitation fuse 134 may not work properly when the power supply unit 150 is low on power. Figure 6 In some embodiments, the power supply unit 150 can be connected to the busbar through the energy conversion module 170. The energy conversion module 170 is used to provide the power supply unit 150 with the power of the busbar. By setting the energy conversion module 170, the power supply unit can automatically draw power from the busbar. This avoids the problem of reduced operating efficiency of the power conversion device caused by the need to shut down the power conversion device when the staff manually replaces the power supply unit to a certain extent.

[0059] In this embodiment, the energy conversion module 170 is a DC-DC converter. The DC-DC converter can convert the bus voltage into a charging voltage for charging the power supply unit. The charging voltage is greater than the current output voltage of the power supply unit. Of course, the energy conversion module 170 can also be a modular component integrated with one or more DC-DC converters or other control circuits. For example, the energy conversion module 170 is a power board or a battery box, etc. This embodiment is not specifically limited here.

[0060] In some embodiments, when the DC positive bus 112 and the DC negative bus 114 are both provided with an excitation fuse 134 and a current detection device 132 connected in series, the excitation fuse 134 and the current detection device 132 connected in series in the DC positive bus 112 and the DC negative bus 114 share the same power supply unit 150. Of course, the excitation fuse 134 and the current detection device 132 connected in series may also share the same controller 140. For example, see Figure 1 . Figure 1 In the exemplary power conversion device 1 , both the DC positive bus 112 and the DC negative bus 114 are provided with an excitation fuse 134 and a current detection device 132 connected in series, and the two current protection units 130 share a controller 140 and a power supply unit 150 .

[0061] In some embodiments, when two or three of the AC A-phase busbar 122, the AC B-phase busbar 124, and the AC C-phase busbar 126 are provided with the excitation fuse 134 and the current detection device 132 connected in series, the excitation fuse 134 and the current detection device 132 connected in series share the same power supply unit 150. Of course, the excitation fuse 134 and the current detection device connected in series may also share the same controller 140. For example, see Figure 3 . Figure 3 In the exemplary power conversion device 1 , the AC A-phase bus 122 , the AC B-phase bus 124 , and the AC C-phase bus 126 are all provided with an excitation fuse 134 and a current detection device 132 connected in series, and share a controller 140 and a power supply unit 150 .

[0062] In some embodiments, when at least two of the DC positive bus 112, the DC negative bus 114, the AC A-phase bus 122, the AC B-phase bus 124, and the AC C-phase bus 126 are provided with an excitation fuse 134 and a current detection device 132 connected in series, the excitation fuse 134 and the current detection device 132 connected in series share the same power supply unit 150. Of course, the excitation fuse 134 and the current detection device 132 connected in series may also share the same controller 140.

[0063] In some embodiments, the excitation fuse 134 and the current detection device 132 arranged in series on the DC side and the AC side may also use different controllers 140 and power supply units 150, respectively. This specification does not specifically limit the embodiments herein.

[0064] According to the protection requirements of different application scenarios, the excitation fuse 134 has different setting methods.

[0065] In some embodiments, the excitation signal of the excitation fuse 134 may be derived from the excitation fuse 134 itself or the current detection device 132. That is, the excitation fuse 134 is set based on itself. Specifically, the excitation fuse 134 may be provided with a plurality of setting gears. When the current detection device 132 or the ammeter built into the excitation fuse 134 detects that the current value reaches or exceeds the current threshold value corresponding to the set setting gear, the excitation fuse 134 triggers the fuse mechanism. Of course, the excitation fuse 134 may also determine whether the current value reaches or exceeds the current threshold value corresponding to the set setting gear by heat accumulation.

[0066] Exemplarily, the excitation fuse 134 is provided with three setting positions. The setting positions are determined as follows.

[0067] The rated current of the excitation fuse 134 is set to I n , the current that can be safely disconnected is I cu Safely disconnectable current I cu With rated current I n The ratio is m.

[0068] Correspondingly, the current range of the first setting gear is as follows.

[0069]

[0070] The current range of the second setting gear is as follows.

[0071]

[0072] The current range of the third setting gear is as follows.

[0073]

[0074] For different application scenarios, the number of setting positions of the excitation fuse 134 and the current range of the setting positions can be adjusted, which is not specifically limited in this embodiment.

[0075] In some embodiments, the excitation fuse 134 can also be set based on the control strategy of the system using the power conversion device 1. Specifically, the excitation fuse 134 and the current detection device 132 are connected to the controller 140. The excitation signal of the excitation fuse 134 comes from the controller 140 of the energy storage system. For example, a current threshold is set in the controller 140. When the controller 140 receives the current value detected by the current detection device 132 and determines that the current current value is greater than the current threshold, the excitation signal is sent to the excitation fuse 134 to control the excitation fuse 134 to melt.

[0076] In some embodiments, the excitation fuse 134 is controlled by the electric energy provided by the power supply unit 150 to excite the fuse mechanism. Specifically, the excitation fuse 134 has an excitation signal input terminal, and the current protection unit 130 further includes a switch unit 136 connected between the excitation signal input terminal and the power supply unit 150. The switch unit 136 is controlled by the controller 140 to be closed or opened.

[0077] The excitation signal input terminal is used to receive an excitation signal for indicating that the excitation fuse 134 is blown.

[0078] The switch unit 136 is used to control the conduction or disconnection between the excitation signal input terminal and the power supply unit 150. The switch unit 136 can be a semiconductor switch, such as MOSFET, IGBT, etc. Of course, the switch unit 136 can also be a mechanical switch. This embodiment is not specifically limited here.

[0079] In some cases, a large short-circuit current may appear in the busbar of the power conversion device 1 in a short time. Since the process of activating the fuse mechanism by the excitation fuse 134 includes at least two control processes: the current detection device 132 detects that the current exceeds the specified threshold value, and the controller 140 determines that the current exceeds the specified threshold value and sends an excitation signal to the excitation fuse 134 or provides an excitation signal to the excitation fuse 134 by closing the switch unit 136. This makes the entire process of activating the fuse mechanism by the excitation fuse 134 take a certain amount of time. Therefore, if the circuit is protected only by the excitation fuse 134 in the current protection unit 130, some components in the circuit are still facing a certain risk of damage due to the fact that it takes a certain amount of time for the excitation fuse 134 to fuse in response to the excitation signal.

[0080] To this end, in the embodiment provided in this specification, a basic fuse 160 is also provided on the busbar of the power conversion device 1 while a current protection unit is provided. The basic fuse 160 may be a one-time fuse or a self-recovering fuse. This embodiment does not specifically limit this. Compared with the excitation fuse 134, the basic fuse 160 is a passive protection element, which can automatically blow when the current flowing through the basic fuse 160 exceeds its set value, and does not depend on the fuse signal. Therefore, the response time of the basic fuse 160 in response to the current exceeding the threshold value and blowing is shorter than the response time of the excitation fuse 134 in response to the current exceeding the threshold value and blowing. By providing the basic fuse 160, the short-circuit current can be cut off in time when a large short-circuit current occurs, which can further reduce the risk of damage to components to a certain extent.

[0081] In some embodiments, the basic fuse 160 may be directly connected in series with the current protection unit 130 in the busbar. That is, the basic fuse 160 may be connected in series with the excitation fuse 134 and the current detection device 132 in the current protection unit 130 .

[0082] Specifically, in the power conversion device 1, at least one of the DC positive bus 112 and the DC negative bus 114 may be provided with a current protection unit 130 and a basic fuse 160. Also, in the power conversion device 1, at least one of the AC A-phase bus 122, the AC B-phase bus 124, and the AC C-phase bus 126 may be provided with a current protection unit 130 and a basic fuse 160. Of course, only one of the DC bus 110 and the AC bus 120 may be provided with a basic fuse 160 in series. This embodiment is not specifically limited here.

[0083] For example, see Figure 7 . Figure 7 In the exemplary power conversion device 1, a current protection unit 130 and a basic fuse 160 are provided on the DC positive bus 112 and the DC negative bus 114. Therefore, when the current protection unit 130 cannot cut off the current in the DC positive bus 112 or the DC negative bus 114 in time, the basic fuse 160 can cut off the current.

[0084] Alternatively, see Figure 8 The AC A-phase busbar 122, the AC B-phase busbar 124, and the AC C-phase busbar 126 are provided with a current protection unit 130 and a basic fuse 160. Therefore, when the current protection unit 130 cannot cut off the current in the AC A-phase busbar 122, the AC B-phase busbar 124, and the AC C-phase busbar 126 in time, the basic fuse 160 can cut off the current.

[0085] Alternatively, see Fig. 9 . Fig. 9In the exemplary power conversion device 1 , the DC positive bus 112 , the DC negative bus 114 , the AC A-phase bus 122 , the AC B-phase bus 124 , and the AC C-phase bus 126 are all provided with a current protection unit 130 and a basic fuse 160 in series.

[0086] In some embodiments, part of the DC busbar 110 or part of the AC busbar 120 is provided with a current protection unit 130. Another part of the DC busbar 110 or the AC busbar 120 is not provided with a current protection unit 130. Accordingly, the busbar not provided with the current protection unit 130 may be provided with a basic fuse 160. Thus, when the current in the busbar not provided with the current protection unit 130 is too large, the basic fuse 160 may be used to protect the components in the circuit.

[0087] For example, see Fig.10 . Fig.10 In the exemplary power conversion device 1 , the DC negative bus 114 is provided with a current protection unit 130 . The DC positive bus 112 , which is not provided with the current protection unit 130 , is provided with a basic fuse 160 .

[0088] Alternatively, see Fig.11 . Fig.11 In the exemplary power conversion device 1 , the AC C-phase bus 126 is provided with a current protection unit 130 connected in series. The AC B-phase bus 124 and the AC A-phase bus 122 , which are not provided with the current protection unit 130 , are provided with basic fuses 160 .

[0089] In some cases, when the current in the busbar of the power conversion device 1 is large, the basic fuse 160 can be used to quickly cut off the current to reduce the risk of component damage. At the same time, in order to prevent the basic fuse 160 from melting when a short-circuit current or overcurrent that can be safely cut off by the excitation fuse 134 occurs. In some embodiments, the melting current intensity of the basic fuse 160 is greater than the melting current intensity of the excitation fuse 134. Thus, when the current in the busbar is within the current range that the excitation fuse 134 can safely cut off, the current can be cut off by the excitation fuse 134. When the current in the busbar exceeds the current range that the excitation fuse 134 can safely cut off, the basic fuse 160 can be used to quickly cut off the current. This can also reduce the replacement frequency of the basic fuse 160 to a certain extent. And, in some embodiments, since the basic fuse 160 can be used to cut off a larger current. The specification parameters of the excitation fuse 134 can also be appropriately reduced.

[0090] The working process of the power conversion device 1 integrated with the current protection unit 130 proposed in the embodiments of this specification can be referred to in Fig.12 .

[0091] Step S110: A current threshold may be set in the power conversion device 1. The current threshold may be determined according to circuit characteristics of a system to which the power conversion device 1 is applied. A current exceeding the current threshold in the circuit may indicate that components may be damaged.

[0092] Step S120 : obtaining the current value detected by the current detection device 132 . The current detection device 132 can detect the current value in the circuit in real time or at a specific frequency. The power conversion device 1 can obtain the current value through the current detection device 132 .

[0093] Step S130: Determine whether the current value is greater than the current threshold. When the current value detected by the current detection device 132 is less than the current threshold, the power conversion device 1 can operate normally. When the current value detected by the current detection device 132 is greater than the current threshold, the power conversion device 1 can perform further operations.

[0094] Step S140: the power conversion device 1 may control the switch unit 136 to be closed.

[0095] Step S150 : after the power conversion device 1 controls the switch unit 136 to close, the power supply unit 150 supplies power to the excitation fuse 134 .

[0096] Step S160: the excitation fuse 134 may be blown to extinguish the arc. Specifically, the excitation fuse 134 may respond to the voltage or current connected to the power supply unit 150 and activate the fusing mechanism to cut off the current.

[0097] In summary, by setting the current protection unit 130 in the busbar of the power conversion device 1, the protection of the circuit can be achieved. Specifically, by setting the current protection unit 130 in the busbar of the power conversion device 1, it is possible to adapt to different circuit protection requirements and achieve arc extinguishing and circuit cutting in the full current range. The fuse is set from the minimum current that can be safely cut off to the maximum current that can be safely cut off according to system requirements, and the design strategy of short-circuit or overcurrent protection can be easily transplanted to other devices with different requirements, thereby reducing the requirements for fuse selection and achieving flexible configuration.

[0098] In the multiple embodiments provided in this specification, the power conversion device 1 can be a converter. For example, the power conversion device is a power storage converter (Power Conversion System, PCS). The converter is a device used to convert the electrical energy stored in an energy storage device such as a battery into alternating current or direct current.

[0099] In some embodiments, the power conversion circuit 100 of the converter 10 includes a DC switch 101 , a voltage stabilizing circuit 102 , an electric energy conversion circuit 103 , a filtering circuit 104 and an AC switch 105 .

[0100] See also Fig.13 The DC load switch in the converter 10 is the DC switch 101 of the converter 10. The capacitor pool is the voltage stabilizing circuit 102 of the converter 10. The converter module is the power conversion circuit 103 of the converter 10. The LC filter unit is the filter circuit 104 of the converter 10. The AC circuit breaker is the AC switch 105 of the converter 10.

[0101] Of course, see Fig.14 . The power conversion device 1 can also be an inverter 20. The power conversion circuit 100 in the inverter 20 includes modules such as a DC load switch, a capacitor pool, an inverter bridge, an LC filter unit and an AC circuit breaker. The DC load switch is the DC switch 101 of the inverter 20. The capacitor pool is the voltage stabilizing circuit 102 of the inverter 20. The inverter bridge is the power conversion circuit 103 of the inverter 20. The LC filter unit is the filter circuit 104 of the inverter 20. The AC circuit breaker is the AC switch 105 of the inverter 20. The embodiments of this specification are not specifically limited here.

[0102] The description of the inverter 20 may refer to the description of the power conversion device 1 or the converter 10. This embodiment will not be described in detail here.

[0103] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. can transmit electrical signals or data to each other.

[0104] It should be understood that the specific examples in this document are only intended to help those skilled in the art better understand the embodiments of this specification, rather than to limit the scope of the present invention.

[0105] It can be understood that in the various embodiments in this specification, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this specification.

[0106] It can be understood that the various embodiments described in this specification can be implemented individually or in combination, and the embodiments of this specification are not limited to this.

[0107] Unless otherwise stated, all technical and scientific terms used in the embodiments of this specification have the same meaning as those generally understood by those skilled in the art of the technical field of this specification. The terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the scope of this specification. The term "and / or" used in this specification includes any and all combinations of one or more related listed items. The singular forms of "a kind of", "above" and "the" used in the embodiments of this specification and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0108] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this specification.

[0109] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0110] In the several embodiments provided in this specification, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0111] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0112] The above is only a specific embodiment of this specification, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in this specification, which should be included in the protection scope of this specification. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A power conversion device (1), characterized in that: The power conversion device (1) comprises: A power conversion circuit (100) connected to a bus; the bus comprises a DC bus (110) and / or an AC bus (120); A current protection unit (130) is arranged in at least one busbar; wherein the current protection unit (130) comprises a current detection device (132) and an excitation fuse (134) connected in series; wherein the current detection device (132) is used to detect the current in the busbar, and the excitation fuse (134) is used to cut off the current in the busbar.

2. The power conversion device (1) according to claim 1, characterized in that: The power conversion device (1) further comprises a controller (140) connected to the excitation fuse (134) and the current detection device (132).

3. The power conversion device (1) according to claim 2, characterized in that: The excitation fuse (134) has an excitation signal input terminal, the power conversion device (1) further includes a power supply unit (150), and the current protection unit (130) further includes a switch unit (136) connected between the excitation signal input terminal and the power supply unit (150), and the switch unit (136) is controlled by the controller (140).

4. The power conversion device (1) according to claim 3, characterized in that: The power supply unit (150) is connected to the busbar via an energy conversion module (170); the energy conversion module (170) is used to provide the power supply unit (150) with the electrical energy of the busbar.

5. The power conversion device (1) according to claim 1, characterized in that: The DC bus (110) comprises a DC positive bus (112) and a DC negative bus (114); At least one of the DC positive busbar (112) and the DC negative busbar (114) is provided with the current protection unit (130); or, At least one of the DC positive busbar (112) and the DC negative busbar (114) is provided with the current protection unit (130) and the basic fuse (160).

6. The power conversion device (1) according to claim 5, characterized in that: The DC busbar (110) not provided with the current protection unit (130) is provided with a basic fuse (160).

7. The power conversion device (1) according to claim 2, characterized in that: The DC bus (110) comprises a DC positive bus (112) and a DC negative bus (114); the DC positive bus (112) and the DC negative bus (114) are respectively provided with the current protection unit (130), and share the same controller (140).

8. The power conversion device (1) according to claim 1, characterized in that: The AC busbar (120) comprises an AC A-phase busbar (122), an AC B-phase busbar (124) and an AC C-phase busbar (126); At least one of the AC A-phase busbar (122), the AC B-phase busbar (124), and the AC C-phase busbar (126) is provided with the current protection unit (130); or, At least one of the AC A-phase busbar (122), the AC B-phase busbar (124), and the AC C-phase busbar (126) is provided with the current protection unit (130) and the basic fuse (160).

9. The power conversion device (1) according to claim 8, characterized in that: The AC busbar (120) not provided with the current protection unit (130) is provided with a basic fuse (160).

10. The power conversion device (1) according to claim 2, characterized in that: The AC busbar (120) comprises an AC A-phase busbar (122), an AC B-phase busbar (124) and an AC C-phase busbar (126); At least two of the AC A-phase busbar (122), the AC B-phase busbar (124), and the AC C-phase busbar (126) are respectively provided with the current protection unit (130), and share the same controller (140).

11. The power conversion device (1) according to any one of claims 5, 6, 8 and 9, characterized in that: The fusing current strength of the basic fuse (160) is greater than the fusing current strength of the excitation fuse (134).

12. The power conversion device (1) according to any one of claims 1 to 10, characterized in that: The power conversion circuit comprises a DC switch (101), a voltage stabilizing circuit (102), an electric energy conversion circuit (103), a filter circuit (104) and an AC switch (105).

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