Power conversion device and power generation system

Abstract

The invention provides a power conversion device and a power generation system, the power conversion device comprises a power board and an arc detection board, and the arc detection board is vertically arranged on the surface of the power board. A first through hole in the arc detection plate penetrates through the arc detection plate in the thickness direction of the arc detection plate, and the Rogowski coil surrounds the first through hole and is laid on the arc detection plate. A power conversion circuit is arranged on the power board, a connecting wire between the power conversion circuit and the direct current input of the power conversion device comprises a U-shaped wire, the U-shaped wire penetrates through the first through hole in the thickness direction of the arc detection board, and the two sides of the U-shaped wire are located on the two sides of the arc detection board respectively. The Rogowski coil is used for sensing alternating current on the connecting wire and generating an arc sensing signal for arc fault detection of the power conversion device. According to the invention, the cost of the power conversion device is effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of power supplies, and in particular, to a power conversion device and a power generation system. Background Art

[0002] To prevent DC arcing caused by problems such as poor contact of PV terminals in the DC side loop of a photovoltaic system, a photovoltaic inverter is required to have an arcing detection function. Specifically, the photovoltaic inverter accurately obtains the characteristic signal of the arc through a current transformer located on the DC side. Then, the photovoltaic inverter processes the characteristic signal of the arc through filtering, amplification, etc., and then analyzes the processed characteristic signal to determine whether there is arcing on the DC side. Although the photovoltaic inverter can achieve arcing detection through a current transformer, since the current transformer is composed of a closed iron core and windings and has a large volume, the cost of the photovoltaic inverter will be too high. Summary of the Invention

[0003] The present application provides a power conversion device and a power generation system, which can reduce the volume of the power conversion device, thereby effectively reducing the cost of the power conversion device.

[0004] In a first aspect, the present application provides a power conversion device, which includes a power board and an arc detection board. The arc detection board is vertically arranged on the surface of the power board. Among them, the arc detection board includes a first through hole, and the first through hole penetrates the arc detection board along the thickness direction of the arc detection board. A Rogowski coil is laid around the first through hole on the arc detection board. A power conversion circuit is arranged on the power board, and the connecting wire between the power conversion circuit and the DC input of the power conversion device includes a U-shaped wire. The U-shaped wire penetrates the first through hole along the thickness direction of the arc detection board, and both sides of the U-shaped wire are located on both sides of the arc detection board. The Rogowski coil is used to sense the alternating current on the connecting wire and generate an arc induction signal for arc fault detection of the power conversion device.

[0005] In this embodiment, the Rogowski coil laid on the arc detection board can be understood as a PCB Rogowski coil. The power conversion device performs arc fault detection through the PCB Rogowski coil. Since the PCB Rogowski coil is a coil printed on a printed circuit board (PCB) and belongs to an air-core coil, obviously, the PCB Rogowski coil does not contain an iron core. Therefore, the volume of the power conversion device can be reduced, thereby effectively reducing the cost of the power conversion device. In addition, the arc detection board is vertically arranged on the surface of the power board, so that the occupied board area of the arc detection board in the power board is small, which is beneficial to the miniaturization design of the power conversion device to further effectively reduce the cost of the power conversion device.

[0006] Combined with the first aspect, in a first possible implementation manner, the arc detection board includes a first layer board and a second layer board arranged in a stacked manner, and multiple groups of vias that surround the first through hole and penetrate the first layer board and the second layer board along the thickness direction of the arc detection board. Each group of vias in the multiple groups of vias includes a conductive first via, second via, third via, and fourth via. The first via and the second via are on the same side of the straight line where the third via and the fourth via are located, and the first via and the fourth via are on the same side of the straight line where the second via and the third via are located. The Rogowski coil includes a conductive coating applied to the inner wall of each via in each group of vias, a first connecting wire between the first via and the second via in each group of vias, a second connecting wire between the third via and the fourth via, a third connecting wire between the second via and the fourth via, and a fourth connecting wire between the first via of one group of vias and the third via of another group of any adjacent two groups of vias. Moreover, the first connecting wire and the second connecting wire are both printed on the first layer board, and the third connecting wire and the fourth connecting wire are both printed on the second layer board.

[0007] In this implementation manner, the Rogowski coil is composed of the conductive coatings applied to the inner walls of the vias in multiple groups of vias on the arc detection board and the connecting wires printed on the arc detection board, and it will not additionally increase the volume of the arc detection board. Therefore, it is beneficial to the miniaturized design of the power conversion device. In addition, when the interior angles of the quadrilateral formed by the first via, the second via, the third via, the fourth via, and the connecting lines between two adjacent vias do not include right angles, that is, when the first via, the second via are misaligned with the third via and the fourth via, the number of turns of the Rogowski coil can be increased, thereby increasing the mutual inductance coefficient. Furthermore, the induced electromotive force gain of the Rogowski coil is greater within the frequency range of a preset frequency band (such as 10 kHz to 60 kHz), and the arc can be accurately detected to achieve reliable arc detection.

[0008] Combined with the first possible implementation manner of the first aspect, in a second possible implementation manner, the number of layers of the arc detection board is odd, then the arc detection board further includes a third layer board, the third layer board is located between the first layer board and the second layer board, and the multiple groups of vias also penetrate the third layer board along the thickness direction of the arc detection board. The power conversion device further includes a return wire of the Rogowski coil, and the return wire is printed on the third layer board. After connecting one end of the Rogowski coil, the return wire passes through the channel formed by the Rogowski coil and the arc detection board to generate an induced electromotive force on the return wire that is opposite to the direction of the induced electromotive force generated by the ripple current in the inductive connecting wire of the Rogowski coil.

[0009] In this embodiment, since the arc fault detection provided by the present application simultaneously detects multiple connecting wires between the power conversion device and the DC input of the power conversion circuit, and all of the above-mentioned multiple connecting wires pass through the Rogowski coil and are all current-carrying conductors to be measured. Therefore, when an arc occurs in one of the above-mentioned multiple connecting wires, the ripple current in other connecting wires is equivalent to interference current, which affects the arc detection accuracy. Based on this, a return wire can be added to the Rogowski coil, and the vertical component of the interfering magnetic field generates an induced electromotive force in the return wire that is equal in magnitude and opposite in direction to the additional electromotive force, so that the influence of the vertical component on the Rogowski coil can be cancelled, thereby improving the detection accuracy of the Rogowski coil.

[0010] In combination with the first possible implementation manner of the first aspect, among the three possible implementation manners, the number of layers of the arc detection board is an even number. Then, the arc detection board further includes a third layer board and a fourth layer board arranged in a stacked manner. The third layer board and the fourth layer board are located between the first layer board and the second layer board, and multiple groups of vias also penetrate through the third layer board and the fourth layer board along the thickness direction of the arc detection board. The power conversion device further includes two return wires of the Rogowski coil, and the two return wires are respectively printed on the third layer board and the fourth layer board. After any one of the two return wires is connected to one end of the Rogowski coil, it passes through the channel formed by the Rogowski coil and the arc detection board, so as to generate an induced electromotive force on the two return wires that is opposite in direction to the induced electromotive force generated by the Rogowski coil inducing the ripple current in the connecting wire.

[0011] In this embodiment, since the arc fault detection provided by the present application simultaneously detects multiple connecting wires between the power conversion device and the DC input of the power conversion circuit, and all of the above-mentioned multiple connecting wires pass through the Rogowski coil and are all current-carrying conductors to be measured. Therefore, when an arc occurs in one of the above-mentioned multiple connecting wires, the ripple current in other connecting wires is equivalent to interference current, which affects the arc detection accuracy. Based on this, a return wire can be added to the Rogowski coil, and the vertical component of the interfering magnetic field generates an induced electromotive force in the return wire that is equal in magnitude and opposite in direction to the additional electromotive force, so that the influence of the vertical component on the Rogowski coil can be cancelled, thereby improving the detection accuracy of the Rogowski coil.

[0012] In combination with any one of the first aspect to the third possible implementation manners of the first aspect, among the four possible implementation manners, the gap formed by the Rogowski coil surrounding the first through hole is smaller than the diameter of the first through hole.

[0013] In this embodiment, the structure formed by surrounding the Rogowski coil around the first through hole is set to be an approximately closed structure. For the Rogowski coil with an approximately closed structure, the position of the conductor under test has little effect on the mutual inductance value, that is, the output voltage is not affected by the distance between the conductor under test and the center of the Rogowski coil. When the conductor under test deviates from the center of the Rogowski coil, compared with the ideal situation without deviation, the magnetic flux of each turn of the coil will change. However, on the side close to the current under test, the magnetic flux increases, and on the side far from the current under test, the magnetic flux decreases, and the total magnetic flux hardly changes. Therefore, in this application, no special setting is required for the distance between the connecting wire and the center of the Rogowski coil, and the accuracy of the induced electromotive force generated by the Rogowski coil can be ensured, thus realizing reliable arc detection.

[0014] Combined with any one of the first aspect to the fourth possible embodiments of the first aspect, in the fifth possible embodiment, the U-shaped wire is a copper bar.

[0015] In this embodiment, the U-shaped wire is a copper bar, which has good heat dissipation effect and good corrosion resistance. Therefore, it can not only be applied to large current application scenarios, but also improve the accuracy of arc detection results.

[0016] Combined with any one of the first aspect to the fifth possible embodiments of the first aspect, in the sixth possible embodiment, the power conversion device further includes a signal conditioning circuit and a controller. Among them, the signal conditioning circuit is connected to the Rogowski coil and is used to filter and amplify the arc induction signal to generate an arc detection signal. The controller is used to control the power conversion device to shut down when the sum of the gains of the signals corresponding to the arc detection signal after fast Fourier transform within a preset frequency band is greater than a threshold.

[0017] Combined with the sixth possible embodiment of the first aspect, in the seventh possible embodiment, the power conversion device further includes a self-check winding. Among them, the controller is further used to output an alternating current to the self-check winding before the power conversion circuit starts to work. The Rogowski coil is further used to sense the alternating current flowing through the self-check winding and generate a self-check induction signal. The signal conditioning circuit is further used to filter and amplify the self-check induction signal to generate a self-check detection signal. The controller is further used to indicate that there is an arc on the self-check winding, that is, to indicate that the arc fault detection function of the power conversion device is normal, and then control the power conversion circuit to start working when the sum of the gains of the signals corresponding to the self-check detection signal after fast Fourier transform within a preset frequency band is greater than a threshold.

[0018] In this embodiment, during each startup process of the power conversion device, the arc fault detection function of the power conversion device is judged through the self-check winding. After it is determined that the arc fault detection function of the power conversion device is normal, the power conversion circuit is controlled to start working, and then the arc detection signal is obtained through the Rogowski coil for arc fault detection. Therefore, the arc detection result can be made more reliable and accurate.

[0019] Combined with the seventh possible embodiment of the first aspect, in the eighth possible embodiment, the arc detection board further includes a second through hole, which penetrates the arc detection board along the thickness direction of the arc detection board. The second through hole is located between the first through hole and the Rogowski coil, and the distance between the second through hole and the first through hole is greater than the safety distance. The self-check winding is laid on the arc detection board and passes through the second through hole.

[0020] Exemplarily, the self-check winding is printed on the arc detection board in the form of copper foil. This setting method will not additionally increase the volume of the arc detection board, thus facilitating the miniaturized design of the power conversion device.

[0021] Combined with any one of the sixth to eighth possible embodiments of the first aspect, in the ninth possible embodiment, the signal conditioning circuit is arranged on the surface of the arc detection board and is located on the periphery of the Rogowski coil.

[0022] In this embodiment, the signal conditioning circuit is arranged on the surface of the arc detection board and is located on the periphery of the Rogowski coil to prevent the signal conditioning circuit from having adverse effects such as interfering with the normal operation of the Rogowski coil, thereby effectively ensuring the detection effect of the Rogowski coil. In addition, the Rogowski coil is located between the signal conditioning circuit and the above-mentioned connecting wire, so that the Rogowski coil can form an effective electromagnetic shielding effect, and can prevent the alternating magnetic field generated near the above-mentioned connecting wire from interfering with the signal conditioning circuit and other adverse effects.

[0023] Combined with any one of the first aspect to the ninth possible embodiment of the first aspect, in the tenth possible embodiment, the arc detection board includes a plurality of first through holes, the Rogowski coil surrounds the plurality of first through holes, and the plurality of first through holes correspond one by one to multiple connecting wires between the power conversion circuit and the DC input of the power conversion device. The U-shaped wire in one connecting wire penetrates through one first through hole along the thickness direction of the arc detection board, and both sides of the U-shaped wire in one connecting wire are located on both sides of the arc detection board respectively.

[0024] In this embodiment, the manner in which multiple connection wires between the power conversion circuit and the DC input of the power conversion device pass through the through-holes may include, in addition to the manner in which all the multiple connection wires pass through a single first through-hole (such as a rectangular through-hole with a smaller width), the manner in which the multiple connection wires pass through multiple first through-holes respectively, so that the structure of the arc detection board is diverse, and thus the structure of the power conversion device is diverse and highly flexible.

[0025] In a second aspect, the present application provides a power generation system, which includes a power conversion device and a photovoltaic module or an energy storage battery, and the DC input of the power conversion device is connected to the photovoltaic module or the energy storage battery. The power conversion device includes a power board and an arc detection board, and the arc detection board is vertically arranged on the surface of the power board. Among them, the arc detection board includes a first through-hole that penetrates the arc detection board along the thickness direction of the arc detection board, and a Rogowski coil is laid around the first through-hole on the arc detection board. A power conversion circuit is arranged on the power board, and the connection wire between the power conversion circuit and the DC input of the power conversion device includes a U-shaped wire that penetrates the first through-hole along the thickness direction of the arc detection board, and both sides of the U-shaped wire are located on both sides of the arc detection board respectively. The Rogowski coil is used to sense the alternating current on the connection wire and generate an arc induction signal for arc fault detection of the power conversion device.

[0026] In this embodiment, the Rogowski coil laid on the arc detection board can be understood as a PCB Rogowski coil. The power conversion device performs arc fault detection through the PCB Rogowski coil. Since the PCB Rogowski coil is a coil printed on the PCB and belongs to an air-core coil, obviously, the PCB Rogowski coil does not contain an iron core. Therefore, the volume of the power conversion device can be reduced, thereby effectively reducing the cost of the power conversion device, and further effectively reducing the cost of the power generation system. In addition, the arc detection board is vertically arranged on the surface of the power board, so that the occupied board area of the arc detection board in the power board is small, which is beneficial to the miniaturization design of the power conversion device, so as to further effectively reduce the cost of the power conversion device, and thus further effectively reduce the cost of the power generation system. Description of the Drawings

[0027] Figure 1 is a schematic diagram of an application scenario of the power generation system provided by the present application;

[0028] Figure 2a is a schematic circuit diagram of the inverter provided by the present application;

[0029] Figure 2b is a schematic internal structure diagram of the inverter provided by the present application;

[0030] Figure 2c is another schematic internal structure diagram of the inverter provided by the present application;

[0031] Figure 2d is another schematic diagram of the internal structure of the inverter provided by this application;

[0032] Figure 3 is another schematic diagram of an application scenario of the power generation system provided by this application;

[0033] Figure 4 is a schematic diagram of the structure of the power generation system provided by this application;

[0034] Figure 5a is a schematic diagram of the structure of the power conversion device provided by this application;

[0035] Figure 5b is another schematic diagram of the structure of the power conversion device provided by this application;

[0036] Figure 5c is yet another schematic diagram of the structure of the power conversion device provided by this application;

[0037] Figure 6 is a wiring schematic diagram of the Rogowski coil provided by this application;

[0038] Figure 7 is a schematic diagram of the position of the self-checking winding provided by this application. Detailed implementation manners

[0039] The power conversion device and the power generation system provided by this application can be applied to various application fields such as the photovoltaic power generation field, the energy storage power generation field, the new energy intelligent microgrid field, and the power transmission and distribution field. The power conversion device provided by this application can be an inverter, a power conversion system (PCS), an uninterruptible power supply (UPS), etc., and is applicable to different application scenarios, such as a photovoltaic power supply scenario, an energy storage power supply scenario, a hybrid photovoltaic and energy storage power supply scenario, a UPS power supply scenario, etc. The following will be described by taking the photovoltaic power supply scenario and the energy storage power supply scenario as examples.

[0040] Refer to Figure 1 , Figure 1 is a schematic diagram of an application scenario of the power generation system provided by this application. In the photovoltaic power supply scenario, the power generation system provided by this application is Figure 1 the photovoltaic power generation system shown, and the power conversion device provided by this application is Figure 1Any one of the inverters 11 to 1n shown. The photovoltaic power generation system includes inverters 11, ……, 1n, photovoltaic modules PV111, PV112, ……, PV1n1, and PV1n2. The DC input i111 of inverter 11 is connected to the positive electrode of photovoltaic module PV111, the DC input i112 is connected to the negative electrodes of photovoltaic modules PV111 and PV112, and the DC input i113 is connected to the positive electrode of photovoltaic module PV112; ……; the DC input i1n1 of inverter 1n is connected to the positive electrode of photovoltaic module PV1n1, the DC input i1n2 is connected to the negative electrodes of photovoltaic modules PV1n1 and PV1n2, and the DC input i1n3 is connected to the positive electrode of photovoltaic module PV1n2. The AC outputs o11 of inverter 11, ……, o1n of inverter 1n are connected in parallel and then connected to the AC grid or household appliances.

[0041] The structures of each of the inverters 11 to 1n are the same. Here, inverter 11 will be taken as an example for introduction. As Figure 2a shown, inverter 11 includes an arc detection module, a DC / DC conversion circuit, a DC / AC conversion circuit, and a controller. Among them, the DC input i111 of inverter 11 is connected to the DC input i111a of the DC / DC conversion circuit, the DC input i112 of inverter 11 is connected to the DC input i111b of the DC / DC conversion circuit, and the DC input i113 of inverter 11 is connected to the DC input i111c of the DC / DC conversion circuit. The DC output of the DC / DC conversion circuit is connected to the DC input of the DC / AC conversion circuit, and the AC output of the DC / AC conversion circuit is connected to the AC output of inverter 11. The arc detection module is arranged between the DC input (including i111, i112, and i113) of inverter 11 and the DC input (including i111a, i111b, and i111c) of the DC / DC conversion circuit, and is used to sense the alternating current on the connection wire a between the DC input i111 of inverter 11 and the DC input i111a of the DC / DC conversion circuit, the connection wire b between the DC input i112 of inverter 11 and the DC input i111b of the DC / DC conversion circuit, and the connection wire c between the DC input i113 of inverter 11 and the DC input i111c of the DC / DC conversion circuit, and generate an arc induction signal.

[0042] To better understand the relative positional relationship among the arc detection module, connection wires a to c, and the DC / DC conversion circuit in inverter 11, here, the arc detection module is a Rogowski coil, and in combination with Figures 2b to 2d the structural schematic diagram of inverter 11 shown, inverter 11 will be introduced. As Figure 2bAs shown, the inverter 11 includes a power board 111 and an arc detection board 112, and the arc detection board 112 is vertically disposed on the surface of the power board 111. Among them, the arc detection board 112 includes a first through hole 1121 in a bow shape, and the first through hole 1121 penetrates the arc detection board 112 along the thickness direction of the arc detection board 112. The Rogowski coil 1122 is laid around the first through hole 1121 on the arc detection board 112. A power conversion circuit 1111 is provided on the power board 111, that is Figure 2a the DC / DC conversion circuit and the DC / AC conversion circuit in. A connection wire a between the DC input of the power conversion circuit 1111 (i.e., the DC input of the DC / DC conversion circuit) and the DC input of the inverter 11, a connection wire b between the DC input i 111b of the power conversion circuit 1111 and the DC input i 112 of the inverter 11, and a connection wire c between the DC input i 111c of the power conversion circuit 1111 and the DC input i 113 of the inverter 11 are provided, corresponding to Figure 2c the three wires passing through the first through hole 1121 in. Taking the connection wire a as an example, the connection wire a includes a U-shaped wire, and the U-shaped wire penetrates the first through hole along the thickness direction of the arc detection board, and both sides of the U-shaped wire are located on both sides of the arc detection board respectively. For the convenience of understanding, the U-shaped wire is divided into three parts here, which are respectively Figure 2d the first connection wire segment a1, the second connection wire segment a2, and the third connection wire segment a3 shown in. Specifically, the arched first connection wire segment a1 penetrates through the first through hole 1121 along the thickness direction of the arc detection board 112. The second connection wire segment a2 and the third connection wire segment a3 are respectively connected to both ends of the first connection wire segment a1, extend along the thickness direction of the power board 111, and are arranged on both sides of the arc detection board 112.

[0043] After the photovoltaic power generation system starts to operate, the inverters 11 to 1n sequentially perform DC conversion and inversion on the direct current output by the respective connected photovoltaic modules, and then obtain alternating current that meets the requirements of the AC power grid, thereby realizing the power supply to the AC power grid or household settings. During the operation of each inverter, the Rogowski coil on the arc detection board of each inverter senses the alternating current on the connection wire between the inverter and the DC input of the DC / DC conversion circuit, and generates an arc induction signal. Then, the controller in each inverter performs arc fault detection based on the arc induction signal generated by the Rogowski coil.

[0044] It can be understood that the Rogowski coil laid on the arc detection board can be regarded as a PCB Rogowski coil. The inverter detects arc faults through the PCB Rogowski coil. Since the PCB Rogowski coil prints the coil on the PCB and belongs to an air-core coil, obviously, the PCB Rogowski coil does not contain an iron core. Therefore, the volume of the inverter can be reduced, thereby effectively reducing the cost of the inverter.

[0045] See Figure 3 , Figure 3 which is another schematic diagram of the application scenario of the power generation system provided by this application. In the energy storage power supply scenario, the power generation system provided by this application is Figure 3 the energy storage power generation system shown in Figure 3 any one of the DC / DC converters 11 to 1n shown in Figure 3 or any one of the energy storage inverters shown in

[0046] Here, the internal structure of any one of the above n DC / DC converters is different from that of the inverter 11 in Figure 1 only in that: the power conversion circuit in any one of the DC / DC converters is a DC / DC conversion circuit. For the description of the structure of other parts in any one of the DC / DC converters except the power conversion circuit, please refer to Figure 1 the description of the corresponding part of the inverter 11 in the embodiment shown in

[0047] After the energy storage power generation system starts to operate, the DC / DC converters 11 to 1n perform DC conversion on the direct current output by the battery clusters they are respectively connected to, and then output it to the energy storage inverters they are respectively connected to. The above-mentioned n energy storage inverters invert the direct current they receive respectively to obtain alternating current that meets the requirements of the AC power grid, thereby realizing power supply to the AC power grid or household settings. During the operation of each DC / DC converter, Rogowski coils on the arc detection boards of the DC / DC converters sense the alternating current on the wires connecting the DC / DC converter and the DC input of the DC / DC conversion circuit, and generate arc induction signals. Then, each DC / DC converter performs arc fault detection based on the arc induction signals generated by the Rogowski coils.

[0048] It can be understood that the Rogowski coils laid on the arc detection board can be understood as PCB Rogowski coils. The DC / DC converter performs arc fault detection through the PCB Rogowski coil. Since the PCB Rogowski coil prints the coil on the PCB and belongs to an air-core coil, obviously, the PCB Rogowski coil does not contain an iron core. Therefore, the volume of the DC / DC converter can be reduced, thereby effectively reducing the cost of the DC / DC converter.

[0049] The above is only an example of the application scenario of the power generation system provided by this application, rather than an exhaustive list. This application does not limit the application scenario.

[0050] The following combines Figures 4 to 7 to give an example and explanation of the working principles of the power conversion device and the power generation system provided by this application.

[0051] See Figure 4 , Figure 4 is a schematic structural diagram of the power generation system provided by this application. As Figure 4 shown, the power generation system includes power conversion devices 11, ……, 1n, DC power supplies 21, ……, and DC power supplies 2n, where n is a positive integer. The DC input i11 of the power conversion device 11 is connected to the DC power supply 21, ……, the DC input i1n of the power conversion device 1n is connected to the DC power supply 2n, and the outputs o11, ……, and o1n of the power conversion devices 11, ……, 1n are connected in parallel and then connected to the power grid. The above-mentioned n DC power supplies can be photovoltaic modules or energy storage batteries.

[0052] Since the structures of each power conversion device in the power generation system are the same, for the convenience of introduction, therefore, the power conversion device 11 will be taken as an example for explanation below. As Figure 5aAs shown, the power conversion device 11 includes a housing 110, a power board 111, an arc detection board 112, a DC input i 11, and an output o11. Among them, the power board 111 and the arc detection board 112 are both located inside the housing 110, and the arc detection board 112 is vertically arranged on the surface of the power board 111. The arc detection board 112 includes a first through hole 1121, and the first through hole 1121 penetrates the arc detection board 112 along the thickness direction of the arc detection board 112. Since Figure 5a is a schematic structural diagram of the power board 111 and the arc detection board 112 at an angle. In order to more clearly describe the positional relationship between the power board 111 and the arc detection board 112, the following will be combined with Figure 5b and Figure 5c the schematic structural diagrams of the power board 111 and the arc detection board 112 at two other angles shown, and an introduction will be made. As Figure 5b and Figure 5c shown, the Rogowski coil 1122 is laid around the first through hole 1121 on the arc detection board 112; a power conversion circuit 1111 (including a DC / DC conversion circuit and / or a DC / AC conversion circuit) is provided on the power board 111, and a connecting wire a, a connecting wire b, and a connecting wire c are sequentially arranged between the DC input of the power conversion circuit 1111 and the DC input of the power conversion device 11. In practical applications, the number of connecting wires between the DC input of the power conversion circuit 1111 and the DC input of the power conversion device 11 is multiple, and the distance between any two adjacent connecting wires is greater than the safety distance.

[0053] Taking the connecting wire a as an example below, the connecting wires between the DC input of the power conversion circuit 1111 and the DC input of the power conversion device 11 will be introduced. The connecting wire a includes a U-shaped wire and a wire located on the power board 111. For the convenience of understanding, here the U-shaped wire is regarded as a combination of three parts, which are respectively Figure 5a and Figure 5b the combination of the first connecting wire segment a1, the second connecting wire segment a2, and the third connecting wire segment a3 shown, and the wire of the connecting wire a located on the power board 111 is regarded as two parts, which are respectively Figure 5a and Figure 5bThe fourth connecting wire segment a4 and the fifth connecting wire segment a5 shown. Among them, the first connecting wire segment a1 passes through the first through hole 1121 along the thickness direction of the arc detection plate 112. The second connecting wire segment a2 and the third connecting wire segment a3 are respectively connected to both ends of the first connecting wire segment a1, extend along the thickness direction of the power board 111, and are respectively connected to one end of the fourth connecting wire segment a4 and one end of the fifth connecting wire segment a5, and are arranged on both sides of the arc detection plate 112. The other ends of the fourth connecting wire segment a4 and the fifth connecting wire segment a5 are respectively connected to the DC input i 11 of the power conversion device 11 and the DC input of the power conversion circuit 1111, and the fourth connecting wire segment a4 and the fifth connecting wire segment a5 are both laid on the power board 111.

[0054] Exemplarily, the first connecting wire segment a1, the second connecting wire segment a2, and the third connecting wire segment a3 are all copper bars, which have good heat dissipation effect and good corrosion resistance. Therefore, they can not only be applied to large-current application scenarios, but also improve the accuracy of arc detection results. The fourth connecting wire segment a4 and the fifth connecting wire segment a5 are both copper foils printed on the power board 111, and will not additionally increase the volume of the power board 111, which is beneficial to the miniaturized design of the power conversion device 11. In addition, when the first connecting wire segment a1 to the third connecting wire segment a3 are made of copper bars and the fourth connecting wire segment a4 and the fifth connecting wire segment a5 are made of copper foils, the power board 111 also includes two conductive holes, which are respectively connected to one end of the fourth connecting wire segment a4 and one end of the fifth connecting wire segment a5. The second connecting wire segment a2 and the third connecting wire segment a3 made of copper bars are respectively inserted into the above two conductive holes, and a reliable electrical connection between the second connecting wire segment a2 and the fourth connecting wire segment a4, and a reliable electrical connection between the third connecting wire segment a3 and the fifth connecting wire segment a5 are achieved by welding. Optionally, the fourth connecting wire segment a4 and the fifth connecting wire segment a5 can also be made of copper bars. In practical applications, the materials of the first connecting wire segment to the fifth connecting wire segment can be reasonably set according to actual needs, and the present application does not limit this.

[0055] The output of the power conversion circuit 1111 is connected to the output o11 of the power conversion device 11, and a part of the connecting wire d between the output of the power conversion circuit 1111 and the output o11 of the power conversion device 11 is laid on the power board 111. The DC input i 11 and the output o11 of the power conversion device 11 both pass through the housing 110 to facilitate the connection between the power conversion device 11 and other external power supply devices or electrical equipment. The direct current output by the DC power supply 21 can be transmitted from the DC input i11 to the power conversion device 11 and then output from the output o11.

[0056] It should be noted that Figures 5a to 5cThe first through-hole 1121 shown is exemplified by a quantity of 1 and a shape of an arc. That is, regardless of whether the number of connecting wires between the power conversion circuit 1111 and the DC input of the power conversion device 11 is one or multiple, all the connecting wires between the power conversion circuit 1111 and the DC input of the power conversion device 11 pass through the same first through-hole. Optionally, when the number of connecting wires between the power conversion circuit 1111 and the DC input of the power conversion device 11 is multiple, the number of first through-holes can also be multiple. Specifically, the arc detection board 112 includes multiple first through-holes, and the distance between any two adjacent first through-holes among the multiple first through-holes is greater than the safety distance; the Rogowski coil 1122 surrounds the multiple first through-holes, and the multiple first through-holes correspond one-to-one to the multiple connecting wires between the power conversion circuit 1111 and the DC input of the power conversion device 11. Taking Figure 5b the connecting wires between the power conversion circuit 1111 and the DC input of the power conversion device 11 shown as connecting wire a, connecting wire b, and connecting wire c as an example, the arc detection board 112 includes 3 first through-holes, namely first through-hole 1121a, first through-hole 1121b, and first through-hole 1121c. And, connecting wire a passes through its corresponding first through-hole 1121a, connecting wire b passes through its corresponding first through-hole 1121b, and connecting wire c passes through its corresponding first through-hole 1121c. Here, for the specific implementation manner in which each of the connecting wires a, b, and c passes through its corresponding first through-hole, please refer to Figure 5a and Figure 5b the position descriptions of the first to fifth connecting wire segments of connecting wire a in the embodiments shown, which will not be elaborated here.

[0057] In addition, the power conversion device 11 further includes a controller 1112 and a signal conditioning circuit 1123 connected to both ends of the Rogowski coil 1122. Exemplarily, as Figure 5cAs shown in the figure, the controller 1112 is disposed on the surface of the power board 111; the signal conditioning circuit 1123 is disposed on the surface of the arc detection board 112 and is located outside the Rogowski coil 1122, so as to prevent the signal conditioning circuit 1123 from having adverse effects on the normal operation of the Rogowski coil 1122, such as interference, thereby effectively ensuring the detection effect of the Rogowski coil 1122. In addition, the Rogowski coil 1122 is located between the signal conditioning circuit 1123 and the above-mentioned connecting wire, so that the Rogowski coil 1122 can form an effective electromagnetic shielding effect, and can prevent the alternating magnetic field generated near the above-mentioned connecting wire from interfering with the signal conditioning circuit 1123 and other adverse effects. In practical applications, the signal conditioning circuit 1123 can be any circuit with filtering and amplifying functions. The input end of the signal conditioning circuit 1123 is used to be connected to both ends of the Rogowski coil 1122 to receive the arc induction signal generated by the Rogowski coil 1122; the output end of the signal conditioning circuit 1123 is used to be connected to the controller 1112 to output an arc detection signal to the controller 1112. Optionally, the signal conditioning circuit 1123 and the controller 1112 can also be located on the same circuit board, such as the power board 111 or the arc detection board 112. It can be understood that, in specific settings, the relative positions between the signal conditioning circuit 1123 and the Rogowski coil 1122 can be reasonably set according to actual needs to ensure the stable operation of the signal conditioning circuit 1123 and the Rogowski coil 1122, which will not be elaborated here.

[0058] Among them, the pattern formed by the Rogowski coil 1122 surrounding the first through hole 1121 can be a closed pattern (such as a ring shape, including a circular ring or a rectangular ring), or an approximately closed pattern. Here, the approximately closed pattern means that the gap (such as Figure 5c the L in) formed by the Rogowski coil 1122 surrounding the first through hole 1121 is greater than 0 and less than the diameter of the first through hole 1121. Here, taking the pattern formed by the Rogowski coil 1122 surrounding the first through hole 1121 as a circular ring as an example, the wiring method of the Rogowski coil 1122 will be introduced in combination with Figure 6 As shown in the figure. Suppose the arc detection board 112 is composed of n stacked boards, and the n boards include a first layer board and a second layer board. As Figure 6 shown in the figure, the arc detection board 112 further includes a plurality of groups of vias that surround the first through hole 1121 and penetrate through the first layer board and the second layer board along the thickness direction of the arc detection board 112. The first group of vias in the plurality of groups of vias includes a conductive first via e11, a second via e21, a third via e31, and a fourth via e41, and the second group of vias in the plurality of groups of vias includes a conductive first via e12, a second via e22, a third via e32, and a fourth via e42. Since the relative positions and the relationships between the vias in each group of vias are the same, for the convenience of introduction, the first group of vias will be taken as an example for description below. As Figure 6As shown, the first via hole e11 and the second via hole e21 are on the same side of the straight line where the third via hole e31 and the fourth via hole e41 are located. Moreover, the first via hole e12 and the fourth via hole e42 are on the same side of the straight line where the second via hole e21 and the third via hole e31 are located. In other words, the positional relationship among the first via hole e11, the second via hole e21, the third via hole e31, and the fourth via hole e41 can be simply regarded as that the first via hole e11, the second via hole e21, the third via hole e31, and the fourth via hole e41 are respectively located at the four vertices of a quadrilateral. The Rogowski coil 1122 includes conductive coatings applied on the inner walls of each via hole in each group, a first connecting wire between the first via hole and the second via hole in each group of via holes, a second connecting wire between the third via hole and the fourth via hole, a third connecting wire between the second via hole and the fourth via hole, and a fourth connecting wire between the first via hole of one group of via holes and the third via hole of another group of adjacent via holes. And the above-mentioned first connecting wire and the above-mentioned second connecting wire are both printed on the first layer board, and the above-mentioned third connecting wire and the above-mentioned fourth connecting wire are both printed on the second layer board. Taking the first group of via holes as an example, the first connecting wire is Figure 6 f11 in Figure 6 the second connecting wire is Figure 6 f12 in Figure 6 the third connecting wire is f13 in Figure 6 and the fourth connecting wire between the first via hole e11 in the first group of via holes and the third via hole e32 in the second group of via holes is Figure 6 f14 in. Here Figure 6 the first via hole to the fourth via hole in each group of via holes are arranged in a clockwise direction. In practical applications, the first via hole to the fourth via hole in each group of via holes can also be arranged in a counterclockwise direction.

[0059] The Rogowski coil 1122 is used to sense the alternating current on the connecting wire between the DC input i11 of the power conversion device 11 and the DC input of the power conversion circuit 1111 for arc fault detection of the power conversion device 11.

[0060] Specifically, the Rogowski coil 1122 in this application is a PCB Rogowski coil. According to the electromagnetic induction law, the alternating current in the above-mentioned connecting wire generates a mutual inductance electromotive force in the coil: V = M*(d i / dt), where M is the mutual inductance coefficient of the PCB Rogowski coil. That is, when the above-mentioned connecting wire is located at the center of the PCB Rogowski coil, the alternating current on the above-mentioned connecting wire will generate a proportional alternating voltage on the PCB Rogowski coil, that is, the arc induction signal. After that, the signal conditioning circuit 1123 filters and amplifies the arc induction signal to generate an arc detection signal. When the sum of the gains of the signal corresponding to the arc detection signal after fast Fourier transform within the preset frequency band is greater than the threshold Kth, it indicates that there is an arc on the above-mentioned connecting wire, and then the controller 1112 controls the power conversion device 11 to shut down. Among them, since the noise frequency band is mainly concentrated in 10 kHz to 60 kHz when an arc occurs on the DC side of the inverter, the preset frequency band can be taken as 10 kHz to 60 kHz. K1 < Kth < K2, and K1 and K2 are determined by the data obtained from multiple experimental tests and statistics. K1 is determined by k1 at multiple different times. For example, K1 is the average value or mode of multiple k1, and k1 is the sum of the gains of the signal corresponding to the arc detection signal after fast Fourier transform within the preset frequency band when there is no arc on the above-mentioned connecting wire; K2 is determined by k2 at multiple different times. For example, K2 is the average value, median, etc. of multiple k2, and k2 is the sum of the gains of the signal corresponding to the arc detection signal after fast Fourier transform within the preset frequency band when there is an arc on the above-mentioned connecting wire. Exemplarily, Kth is taken as 18.

[0061] In addition, according to the electromagnetic induction law, the interference current perpendicular or parallel to the current-carrying conductor will generate an interference magnetic field in the Rogowski coil, affecting the mutual inductance and inducing an additional electromotive force in the PCB Rogowski coil, which affects the accuracy of current measurement. Since the arc fault detection provided in this application simultaneously detects multiple connecting wires between the power conversion device 11 and the DC input of the power conversion circuit, and all of the above-mentioned multiple connecting wires pass through the PCB Rogowski coil and are all current-carrying conductors to be measured. Therefore, when an arc occurs in one of the above-mentioned multiple connecting wires, the ripple current in the other connecting wires is equivalent to an interference current, affecting the arc detection accuracy. Based on this, one or two return wires can be added to the PCB Rogowski coil. The vertical component of the interference magnetic field generates an induced electromotive force in the return wire that is equal in magnitude and opposite in direction to the additional electromotive force, so that the influence of the vertical component on the Rogowski coil can be offset, thereby improving the detection accuracy of the PCB Rogowski coil.

[0062] Here, the number of return wires set in the PCB Rogowski coil depends on whether the number of layers n of the arc detection board 112 is odd or even, specifically as follows:

[0063] In the case where n is odd, the n-layer board further includes a third layer board, and the power conversion device 11 further includes a return wire of the Rogowski coil 1122. Among them, the third layer board is located between the first layer board and the second layer board, and multiple vias of the Rogowski coil 1122 also penetrate the third layer board along the thickness direction of the arc detection board 112. A return wire of the Rogowski coil 1122 is printed on the third layer board. After connecting one end (i.e., the outgoing end) of the Rogowski coil 1122, it passes through the channel formed by the Rogowski coil 1122 and the arc detection board 112, so as to generate an induced electromotive force on the return wire that is opposite to the direction of the induced electromotive force generated by the Rogowski coil 1122 inducing the ripple current (interference current) in the above other connecting wires, thereby reducing or even canceling the influence of the vertical component of the interference magnetic field generated by the interference current in the Rogowski coil 1122 on the Rogowski coil 1122. Exemplarily, a return wire of the Rogowski coil 1122 is, for example, Figure 6 a trace that winds around the first through hole 1121 for one week and is approximately circular and located within the circular ring area formed by the Rogowski coil 1122. Preferably, in order to minimize the influence of the interference magnetic field on the Rogowski coil 1122, it is necessary to set the direction of the induced electromotive force generated on the return wire to be opposite to the direction of the induced electromotive force generated by the interference current, and the magnitude of the induced electromotive force generated on the return wire is the same as the magnitude of the induced electromotive force generated by the interference current, so as to cancel the influence of the vertical component of the interference magnetic field generated by the interference current in the Rogowski coil 1122 on the Rogowski coil 1122.

[0064] Exemplarily, when n = 5, the arc detection board 112 further includes a top layer board and a bottom layer board. The first layer board, the third layer board, and the second layer board are sequentially stacked between the top layer board and the bottom layer board. Both the top layer board and the bottom layer board are coated with copper as shielding. The first layer board and the second layer board serve as the wiring layers of the Rogowski coil 1122, and the third layer board serves as the wiring layer of a return wire of the Rogowski coil 1122. Obviously, with such a setting, a return wire of the Rogowski coil 1122 can be located in the central layer of the arc detection board 112 with a 5-layer board structure, so as to minimize the influence of the vertical component of the interference magnetic field on the Rogowski coil 1122.

[0065] When n is an even number, the n-layer board further includes a third layer board and a fourth layer board which are stacked, and the power conversion device 11 further includes two return wires of the Rogowski coil 1122. Among them, both the third layer board and the fourth layer board are located between the first layer board and the second layer board, and multiple groups of vias of the Rogowski coil 1122 also penetrate the third layer board and the fourth layer board along the thickness direction of the arc detection board 112. The two return wires of the Rogowski coil 1122 are respectively printed on the third layer board and the fourth layer board, and after any one of the two return wires is connected to one end (i.e., the outgoing end) of the Rogowski coil 1122, it passes through the channel formed by the Rogowski coil 1122 and the arc detection board 112, so as to generate an induced electromotive force on the two return wires that is opposite to the direction of the induced electromotive force generated by the Rogowski coil 1122 inducing the ripple current (interference current) in the above other connecting wires, thereby reducing or even canceling the influence of the vertical component of the interference magnetic field generated by the interference current in the Rogowski coil 1122 on the Rogowski coil 1122. Preferably, in order to minimize the influence of the interference magnetic field on the Rogowski coil 1122, it is necessary to set the direction of the induced electromotive force generated on the two return wires to be opposite to the direction of the induced electromotive force generated by the interference current, and the magnitude of the induced electromotive force generated on the two return wires is the same as the magnitude of the induced electromotive force generated by the interference current, so as to cancel the influence of the vertical component of the interference magnetic field generated by the interference current in the Rogowski coil 1122 on the Rogowski coil 1122.

[0066] Exemplarily, when n = 6, the arc detection board 112 further includes a top layer board and a bottom layer board, and the first layer board, the third layer board, the fourth layer board and the second layer board are sequentially stacked between the top layer board and the bottom layer board. Both the top layer board and the bottom layer board are coated with copper as shielding, the first layer board and the second layer board serve as the wiring layers of the Rogowski coil 1122, and the third layer board and the fourth layer board serve as the wiring layers of the two return wires of the Rogowski coil 1122. Obviously, with such a setting, the two return wires of the Rogowski coil 1122 can be located in the central layer of the arc detection board 112 with a 6-layer board structure, so as to minimize the influence of the vertical component of the interference magnetic field on the Rogowski coil 1122.

[0067] Furthermore, to ensure more reliable arc detection results, a self-check winding is also provided in the power conversion device 11. During each startup process of the power conversion device 11, it will judge whether the arc fault detection function of the power conversion device 11 is normal through the self-check winding.

[0068] Specifically, as Figure 7As shown, the arc detection board 112 further includes a second through hole 1124, and the power conversion device 11 further includes a self-check winding 1125. Among them, the second through hole 1124 penetrates the arc detection board 112 along the thickness direction of the arc detection board 112. The second through hole 1124 is located between the first through hole 1121 and the Rogowski coil 1122. Moreover, the distance between the second through hole 1124 and the first through hole 1121 is greater than the safety distance. The self-check winding 1125 is laid (such as printed) on the arc detection board 112 and passes through the second through hole 1124. The self-check winding 1125 is located outside the wiring area of the Rogowski coil 1122.

[0069] Before the power conversion circuit 1111 starts to work, the controller 1112 outputs an alternating current (i.e., a high-frequency PWM signal) to the self-check winding 1125. The Rogowski coil 1122 senses the alternating current flowing through the self-check winding 1125 and generates a proportional alternating voltage, that is, the self-check induction signal. Then, after the signal conditioning circuit 1123 filters and amplifies the self-check induction signal, a self-check detection signal is generated. When the sum of the gains of the signals corresponding to the self-check detection signal after fast Fourier transform within a preset frequency band by the controller 1112 is greater than the threshold, it indicates that there is an arc on the above self-check winding, that is, it indicates that the arc fault detection function of the power conversion device 11 is normal, and then controls the power conversion circuit 1111 to start working.

[0070] In addition, the following settings can be made between the power board 111 and the arc detection board 112 to make the arc detection board 112 vertically arranged on the surface of the power board 111: such as Figure 7 As shown, the edge of the arc detection board 112 includes a conductive protrusion 1126 and a conductive protrusion 1127. The signal conditioning circuit 1123 is electrically connected to the conductive protrusion 1126 and the conductive protrusion 1127. The power board 111 includes two conductive holes (not shown in the figure). The conductive protrusion 1126 and the conductive protrusion 1127 are respectively inserted into the two conductive holes, and the electrical connection between the above two conductive protrusions and the above two conductive holes is realized. Generally speaking, the signal transmission function can be realized between the power board 111 and the arc detection board 112 through the electrical connection between the conductive hole and the conductive protrusion. The arc detection signal or the self-check detection signal generated by the signal conditioning circuit 1123 in the arc detection board 112 can be transmitted to the controller 1112 in the power board 111 through the conduction path between the above conductive hole and the above conductive protrusion. To sum up, in the present application, through the plug-in connection between the conductive protrusion and the conductive hole, not only the fixed connection between the power board 111 and the arc detection board 112 can be realized, but also the signal connection between the signal conditioning circuit 1123 and the controller 1112 can be realized.

[0071] In practical applications, the conductive protrusions can specifically be tin fingers. After the conductive protrusions are inserted into the conductive holes, reliable connection between the conductive protrusions and the conductive holes can be achieved by welding. Additionally, the conductive holes can specifically be metallized holes, or through-holes or blind holes with conductive materials on their inner walls, etc. In specific settings, the specific structural shapes of the conductive holes and the conductive protrusions can be flexibly adjusted according to actual requirements, and the present application places no restrictions thereon.

[0072] Furthermore, the way that the first connecting wire segment passes through the first through-hole along the thickness direction of the arc detection plate 112 in the present application is illustrated by the arched first connecting wire segment a1 in Figure 5a . In practical applications, the first connecting wire segment can also pass through the first through-hole along the thickness direction of the arc detection plate 112 in the form of a semi-rectangle, and the present application places no restrictions thereon. The extending directions of the second connecting wire segment and the third connecting wire segment along the thickness direction of the power board in the present application are illustrated by the direction perpendicular to the power board 111 shown in Figure 5a . In practical applications, directions with an angular error (such as within 27 degrees) from the direction perpendicular to the power board 111 also belong to the above-mentioned extending directions. In addition, the shapes and sizes of the first through-hole to the second through-hole, and the first via to the fourth via in the present application can be reasonably set according to actual needs, and the present application places no restrictions thereon.

[0073] In the present application, the Rogowski coil 1122 laid on the arc detection plate 112 can be understood as a PCB Rogowski coil. The power conversion device performs arc fault detection through the PCB Rogowski coil. Since the PCB Rogowski coil prints the coil on the PCB and belongs to an air-core coil, obviously, the PCB Rogowski coil does not contain an iron core. Therefore, the volume of the power conversion device can be reduced, thereby effectively reducing the cost of the power conversion device. In addition, the mutual inductance coefficient M of the PCB Rogowski coil is related to the number of turns, the thickness of the board, the inner diameter and the outer diameter of the coil, and other body structure parameters. The PCB Rogowski coil provided in the present application for arc fault detection is a closed structure or an approximately closed structure. For the PCB Rogowski coil with a closed structure or an approximately closed structure, the position of the measured conductor has almost no influence on the mutual inductance value, that is, the output voltage is not affected by the distance between the measured conductor and the center of the PCB Rogowski coil. When the measured conductor deviates from the center of the PCB Rogowski coil, compared with the ideal situation without deviation, the magnetic flux of each turn of the coil will change. However, on the side close to the measured current, the magnetic flux increases, and on the side far from the measured current, the magnetic flux decreases, and the total magnetic flux hardly changes. Therefore, the present application does not make special settings on the distance between the above-mentioned connecting wire and the center of the PCB Rogowski coil, and can also ensure the accuracy of the induced electromotive force generated by the PCB Rogowski coil, thereby realizing reliable arc detection.

[0074] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A power conversion device, characterized in that: The power conversion device comprises a power board and an arc detection board, wherein the arc detection board is vertically arranged on the surface of the power board, wherein: The arc detection plate comprises a first through hole, the first through hole penetrates the arc detection plate along the thickness direction of the arc detection plate, and the Rogowski coil is laid on the arc detection plate around the first through hole; The power board is provided with a power conversion circuit, and the connecting wire between the power conversion circuit and the DC input of the power conversion device comprises a U-shaped wire, the U-shaped wire passes through the first through hole along the thickness direction of the arc detection board, and the two sides of the U-shaped wire are respectively located at the two sides of the arc detection board; The Rogowski coil is used to sense the alternating current on the connecting wire and generate an arc induction signal for arc fault detection of the power conversion device.

2. The power conversion device according to claim 1, characterized in that: The arc detection board comprises a first layer board and a second layer board which are stacked, and a plurality of groups of via holes which surround the first through hole and penetrate the first layer board and the second layer board along the thickness direction of the arc detection board; Each group of vias in the plurality of groups of vias includes a conductive first via, a second via, a third via and a fourth via, the first via and the second via are located on the same side of a straight line where the third via and the fourth via are located, and the first via and the fourth via are located on the same side of a straight line where the second via and the third via are located; The Rogowski coil includes a conductive coating applied to the inner wall of each via in each group of vias, a first connecting wire between the first via and the second via in each group of vias, a second connecting wire between the third via and the fourth via, a third connecting wire between the second via and the fourth via, and a fourth connecting wire between the first via of one group of vias in any two adjacent groups of vias and the third via of the other group of vias, and the first connecting wire and the second connecting wire are both printed on the first layer board, and the third connecting wire and the fourth connecting wire are both printed on the second layer board.

3. The power conversion device according to claim 2, characterized in that: If the number of layers of the arc detection board is an odd number, the arc detection board further includes a third layer board, the third layer board is located between the first layer board and the second layer board, and the plurality of groups of vias also penetrate the third layer board along the thickness direction of the arc detection board; The power conversion device also includes a return wire of the Rogowski coil, which is printed on the third layer board; after the return wire is connected to one end of the Rogowski coil, it passes through a channel surrounded by the Rogowski coil and the arc detection board to generate an induced electromotive force on the return wire in the opposite direction to the induced electromotive force generated by the Rogowski coil inducing the ripple current in the connecting wire.

4. The power conversion device according to claim 2, characterized in that: The number of layers of the arc detection board is an even number, then the arc detection board further comprises a third layer board and a fourth layer board which are stacked, the third layer board and the fourth layer board are located between the first layer board and the second layer board, and the plurality of groups of vias also penetrate the third layer board and the fourth layer board along the thickness direction of the arc detection board; The power conversion device also includes two return wires of the Rogowski coil, and the two return wires are printed on the third layer board and the fourth layer board respectively; after any one of the two return wires is connected to one end of the Rogowski coil, it passes through the channel surrounded by the Rogowski coil and the arc detection board to generate an induced electromotive force on the two return wires in the opposite direction to the induced electromotive force generated by the Rogowski coil inducing the ripple current in the connecting wire.

5. The power conversion device according to any one of claims 1 to 4, characterized in that: A gap formed by the Rogowski coil surrounding the first through hole is smaller than a diameter of the first through hole.

6. The power conversion device according to any one of claims 1 to 5, characterized in that: The U-shaped conductor is a copper busbar.

7. The power conversion device according to any one of claims 1 to 6, characterized in that: The power conversion device also includes a signal conditioning circuit and a controller, wherein: The signal conditioning circuit is connected to the Rogowski coil and is used to filter and amplify the arc induction signal to generate an arc detection signal; The controller is used to control the power conversion device to shut down when the sum of gains corresponding to the signals after the arc detection signal is fast Fourier transformed within a preset frequency band is greater than a threshold.

8. The power conversion device according to claim 7, characterized in that: The power conversion device also includes a self-test winding, wherein: The controller is also used to output an alternating current to the self-test winding before the power conversion circuit starts working; The Rogowski coil is also used to sense the alternating current flowing through the self-test winding and generate a self-test sensing signal; The signal conditioning circuit is also used to generate a self-test detection signal after filtering and amplifying the self-test sensing signal; The controller is also used to control the power conversion circuit to start working when the sum of gains corresponding to the signals after the fast Fourier transform of the self-test detection signal in the preset frequency band is greater than the threshold.

9. The power conversion device according to claim 8, characterized in that: The arc detection board also includes a second through hole, which penetrates the arc detection board along the thickness direction of the arc detection board, and the second through hole is located between the first through hole and the Rogowski coil, and the distance between the second through hole and the first through hole is greater than the safety distance, and the self-test winding is laid on the arc detection board and passes through the second through hole.

10. The power conversion device according to any one of claims 7 to 9, characterized in that: The signal conditioning circuit is arranged on the surface of the arc detection board and is located outside the Rogowski coil.

11. The power conversion device according to any one of claims 1 to 10, characterized in that: The arc detection board includes a plurality of the first through holes, the Rogowski coil surrounds the plurality of the first through holes, the plurality of the first through holes correspond one-to-one to a plurality of the connecting wires between the power conversion circuit and the DC input of the power conversion device, a U-shaped wire in one of the connecting wires passes through one of the first through holes along the thickness direction of the arc detection board, and two sides of the U-shaped wire in one of the connecting wires are respectively located on two sides of the arc detection board.

12. A power generation system, characterized in that: The power generation system comprises a power conversion device and a photovoltaic module or an energy storage battery, wherein the DC input of the power conversion device is connected to the photovoltaic module or the energy storage battery, wherein: The power conversion device comprises a power board and an arc detection board, wherein the arc detection board is vertically arranged on the surface of the power board; The arc detection plate comprises a first through hole, the first through hole penetrates the arc detection plate along the thickness direction of the arc detection plate, and the Rogowski coil is laid on the arc detection plate around the first through hole; The power board is provided with a power conversion circuit, and the connecting wire between the power conversion circuit and the DC input of the power conversion device comprises a U-shaped wire, the U-shaped wire passes through the first through hole along the thickness direction of the arc detection board, and the two sides of the U-shaped wire are respectively located at the two sides of the arc detection board; The Rogowski coil is used to sense the alternating current on the connecting wire and generate an arc induction signal for arc fault detection of the power conversion device.

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