A cascade high-voltage isolation heat dissipation integrated power unit module

Abstract

This invention relates to the field of power electronics technology and discloses a cascaded high-voltage isolated heat dissipation integrated power unit module. It includes a housing, a high-voltage region containing high-voltage components, an isolation region containing isolation components, and a low-voltage region containing low-voltage components. The high-voltage region, isolation region, and low-voltage region are sequentially arranged within the housing. A first circuit board is mounted in the high-voltage region, and its surface is used to mount the high-voltage components. The isolation region is used to mount the isolation components. A second circuit board is mounted in the low-voltage region, and its surface is used to mount the low-voltage components. A main cooling channel is formed in the area between the bottom plate of the housing and the lower part of the first circuit board, inside the isolation region, and between the bottom plate of the housing and the lower part of the second circuit board, for the flow of cooling gas to dissipate heat from the high-voltage components, isolation components, and low-voltage components. By installing a heat sink in the main cooling channel and isolating the isolation components in the isolation region, isolation and heat dissipation of the power unit are achieved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of power electronics technology, and in particular to a cascaded high-voltage isolated heat dissipation integrated power unit module. Background Technology

[0002] In recent years, with the rapid development of power electronics technology, the integration of traditional cascaded high-voltage frequency conversion technology and high-frequency isolated DC-DC power conversion schemes has formed a new type of cascaded isolated high-voltage power supply technology represented by power electronic transformers. It has advantages such as high efficiency, high power density, easy expansion, and flexible power supply. It has been gradually introduced to the market and has become an important development direction in the field of power electronics.

[0003] However, cascaded power units include high-voltage terminals, isolation circuits, and low-voltage terminals, making them complex in function and requiring high voltage isolation. Furthermore, the high-voltage and low-voltage terminals integrate multiple circuits, resulting in multiple heat sources. The isolation circuits also generate heat, making heat dissipation a crucial consideration. Moreover, the integrated design of magnetic components in the isolation circuits introduces more complex electromagnetic interference issues. Therefore, the design of cascaded power unit modules faces key challenges such as high circuit functional integration, high voltage isolation requirements, the difficulty of heat dissipation design for multiple heat sources, and electromagnetic compatibility.

[0004] How to design cascaded power unit modules while ensuring effective heat dissipation and electromagnetic isolation is a problem that urgently needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide at least one cascaded high-voltage isolated heat dissipation integrated power unit module. By setting up a main cooling channel and an auxiliary cooling channel, the heat dissipation problem of the cascaded high-voltage power module can be solved. By setting up different components in different areas to shield electromagnetic components, the electromagnetic interference problem can be solved. At least the technical effects of effective heat dissipation and electromagnetic isolation can be achieved.

[0006] To address the aforementioned technical problems, at least one embodiment of this application provides a cascaded high-voltage isolated heat dissipation integrated power unit module, comprising: a housing, a high-voltage region containing high-voltage components, an isolation region containing isolation components, and a low-voltage region containing low-voltage components. The high-voltage region, isolation region, and low-voltage region are sequentially disposed within the housing. The high-voltage region includes a first circuit board, the surface of which is used to mount the high-voltage components. The isolation region is used to mount the isolation components. The low-voltage region includes a second circuit board, the surface of which is used to mount the low-voltage components. A main cooling channel is formed in the region between the bottom plate of the housing and the lower part of the first circuit board, inside the isolation region, and between the bottom plate of the housing and the lower part of the second circuit board, for the flow of cooling gas to dissipate heat from the high-voltage components, isolation components, and low-voltage components.

[0007] The embodiments of this application provide a cascaded high-voltage isolated heat dissipation integrated power unit module. Compared with the prior art, it adopts a method of isolating magnetic components and dissipating heat from power components. Due to the isolation, the interference problem between the equipotential of high-voltage components and the equipotential of low-voltage components is solved. It adopts a main cooling channel and an auxiliary cooling channel to dissipate heat from power components and control components respectively, thus solving the heat dissipation problem of the power unit and realizing the modularization of the power unit.

[0008] A cascaded high-voltage isolated heat dissipation integrated power unit module includes: a housing, a high-voltage region containing high-voltage components, an isolation region containing isolation components, and a low-voltage region containing low-voltage components. The high-voltage region, isolation region, and low-voltage region are sequentially arranged within the housing. A first circuit board is mounted in the high-voltage region, and its surface is used to mount the high-voltage components. The isolation region is used to mount the isolation components. A second circuit board is mounted in the low-voltage region, and its surface is used to mount the low-voltage components. A main cooling channel is formed in the area between the bottom plate of the housing and the lower part of the first circuit board, inside the isolation region, and between the bottom plate of the housing and the lower part of the second circuit board, for the flow of cooling gas to dissipate heat from the high-voltage components, isolation components, and low-voltage components. Using a main cooling channel to dissipate heat from each component solves the module's heat dissipation problem.

[0009] In addition, the integrated isolation and heat dissipation power unit module also includes auxiliary cooling channels. These auxiliary cooling channels are formed in the area between the top plate of the outer casing and the upper part of the first circuit board, the area between the outside of the isolation area and the top plate of the outer casing, and the area between the top plate of the outer casing and the upper part of the second circuit board. These channels facilitate the flow of cooling gas to dissipate heat from the high-voltage components, the isolation components, and the low-voltage components. By employing both main and auxiliary cooling channels to dissipate heat from each component, the module's heat dissipation problem is further solved.

[0010] In addition, the isolation area is equipped with an isolation frame, which, together with the bottom plate of the outer casing, the first side plate of the outer casing, and the third side plate of the outer casing, forms an isolation space. The isolation components are disposed within this isolation space, and the isolation frame is positioned between the high-voltage and low-voltage areas for insulation isolation between the high-voltage components, the isolation components, and the low-voltage components. A main cooling channel is formed in the area between the bottom plate of the outer casing and the lower part of the first circuit board, the area inside the isolation frame, and the area between the bottom plate of the outer casing and the lower part of the second circuit board. The top of the isolation frame is at a predetermined distance from the top plate of the outer casing, forming a gap area between the top of the isolation frame and the top plate of the outer casing. Auxiliary cooling channels are formed in the area between the top plate of the outer casing and the upper surface of the first circuit board, the gap area, and the area between the top plate of the outer casing and the upper surface of the second circuit board. The first side plate and the third side plate of the outer casing are positioned opposite each other. The isolation frame isolates the magnetic isolation components from the high-voltage and low-voltage components, reducing mutual interference between the high-voltage components, the low-voltage components, and the isolation components.

[0011] Furthermore, the isolation frame includes a first isolation plate, a second isolation plate, and a third isolation plate. The first side of the first isolation plate is connected to the first circuit board, the first side of the second isolation plate is connected to the second circuit board, and the third side of the first isolation plate is connected to the first side of the third isolation plate. The third side of the second isolation plate is connected to the third side of the third isolation plate. The first, second, and third isolation plates, the bottom plate of the outer casing, the first side plate of the outer casing, and the third side plate of the outer casing form an isolation space for housing the isolation components. The third isolation plate is the top plate of the isolation frame. The first and third sides of the same plate are arranged opposite to each other, and the first and third side plates of the outer casing are also arranged opposite to each other. The sealed, insulated isolation frame surrounds the magnetic components, preventing electromagnetic interference from the magnetic components to the high-voltage and low-voltage components.

[0012] Additionally, a shielding plate is included. A first shielding plate is disposed between a first isolation plate and an isolation assembly, and a second shielding plate is disposed between a second isolation plate and an isolation assembly. The first side edges of the first and second shielding plates are connected to a third isolation plate. The first shielding plate is fixedly connected to the first isolation plate, and the third side edge of the first shielding plate does not extend beyond the first side edge of the first isolation plate. The second shielding plate is fixedly connected to the second isolation plate, and the third side edge of the second shielding plate does not extend beyond the first side edge of the second isolation plate. The shielding plates further provide electromagnetic shielding for the magnetic components, further isolating mutual interference between the high-voltage components, low-voltage components, and isolation components.

[0013] In addition, a first heat sink is provided at the bottom of the first circuit board to dissipate heat from the power devices in the high-voltage assembly. A second heat sink is provided at the bottom of the second circuit board to dissipate heat from the power devices in the low-voltage assembly. The first and second heat sinks are located in the main cooling channel. The use of heat sinks for heat dissipation, combined with airflow in the main cooling channel to remove heat, ensures timely heat dissipation.

[0014] Furthermore, the first heat sink is sealed to the side panel of the housing, dividing the high-pressure area into upper and lower sections that are not interconnected, preventing gas from the main cooling channel from entering the auxiliary cooling channel. Similarly, the second heat sink is sealed to the side panel of the housing, dividing the low-pressure area into upper and lower sections that are not interconnected, preventing gas from the main cooling channel from entering the auxiliary cooling channel. By separating the heat dissipation of the power devices and the control devices, it is ensured that the heat generated by the power devices does not affect the control devices.

[0015] In addition, a baffle is installed in the main cooling channel. The first baffle is located on the bottom plate of the outer casing below the first isolation plate, and the second baffle is located on the bottom plate of the outer casing below the second isolation plate. The first and second baffles are symmetrically arranged, and the distance between them meets the creepage requirements. An isolation pad is installed between the first and second baffles, and an isolation component is fixedly installed on the isolation pad. By installing the baffles, the airflow in the main cooling channel is smooth, improving the heat dissipation effect.

[0016] In addition, the first and second spoilers have the same structure, with a right-angled triangle cross-section. The hypotenuse of the right-angled triangle of the first spoiler faces the first radiator in the main cooling channel. A first distance is provided between the highest point of the cross-section of the first spoiler and the first side of the first isolation plate. A first distance is also provided between the highest point of the cross-section of the second spoiler and the first side of the second isolation plate. The spoilers are provided to ensure smooth airflow in the main cooling channel.

[0017] Furthermore, the outer casing is insulated and includes a bottom plate, a top plate, and first to fourth side plates. The bottom plate has a first, second, third, and fourth side plate on each of its four sides. The top plate is opposite to the bottom plate, the first and third side plates are opposite to each other, and the second and fourth side plates are opposite to each other. The second side plate is located on the high-voltage component side, and the fourth side plate is located on the low-voltage component side. A first opening for the main cooling channel is located on the second side plate near the main cooling channel. A first opening for the auxiliary cooling channel is located on the second side plate near the top plate of the casing. A second opening for the main cooling channel is located on the fourth side plate near the main cooling channel. A second opening for the auxiliary cooling channel is located on the second side plate near the top plate. The use of an insulated casing ensures electrical isolation between the power unit module and the casing. Ventilation holes are provided on the casing to facilitate airflow.

[0018] In addition, a grid is installed on the first opening of the auxiliary cooling channel to control the air intake of the auxiliary cooling channel. A first sealing strip is installed on the second opening of the main cooling channel, and a second sealing strip is installed on the second opening of the auxiliary cooling channel for sealing connection with external equipment. The air flow in the cooling channel is controlled by the grid. The air flow is increased when the heat is high and decreased when the heat is low, thus ensuring the heat dissipation effect.

[0019] In addition, the power unit circuit includes a high-voltage component, an isolation component, and a low-voltage component connected in sequence. The high-voltage component includes an NPC three-level circuit, a discharge resistor, and a series half-bridge topology for cascade rectification and high-voltage high-frequency conversion. The isolation component includes magnetic elements for high-voltage and low-voltage isolation. The low-voltage component includes an H-bridge topology for low-voltage high-frequency conversion and output DC voltage. Through the isolation component, the conversion from high voltage to low voltage and the conversion from AC to DC are realized.

[0020] In addition, a third shielding plate is provided on the top plate of the housing corresponding to the position of the discharge resistor, and is fixedly connected to the top plate of the housing. A fourth shielding plate is provided on the top plate of the housing corresponding to the position of the low-voltage component, and is fixedly connected to the top plate of the housing. By providing shielding plates, mutual interference between the external environment and the device is prevented.

[0021] In addition, the transformer core, first heat sink, second heat sink, and all shielding plates in the isolation assembly are connected to the intermediate ground terminal of the high-voltage assembly as a clamping grounding point. The setting of the floating ground point ensures that the floating grounds of the power units of multiple branches can be connected to achieve cascading. Attached Figure Description

[0022] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0023] Figure 1 This is a schematic diagram of the module housing structure according to an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the module's front sectional view structure according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of a module side sectional view structure provided according to an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the circuit principle structure of a power module according to an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the principle structure of a power module cascade circuit according to an embodiment of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of the present invention to enable the reader to better understand the present invention. However, the technical solutions claimed in the present invention can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0029] Example 1:

[0030] The embodiments of the present invention relate to a cascaded high-voltage isolated heat dissipation integrated power unit module.

[0031] Compared with the prior art, the embodiments of the present invention solve the mutual interference between high-voltage components and low-voltage components by adopting isolation settings, integrating heat dissipation with the housing, and using cooling channels to dissipate heat from components, thus solving the heat dissipation problem of the power unit.

[0032] The following is a detailed description of the implementation details of a cascaded high-voltage isolated heat dissipation integrated power unit module of this embodiment. The following content is only for the convenience of understanding and is not necessary for implementing this solution.

[0033] The present invention provides a cascaded high-voltage isolated heat dissipation integrated power unit module, comprising: a housing, a high-voltage region where a high-voltage component is located, an isolation region where an isolation component is located, and a low-voltage region where a low-voltage component is located. The high-voltage region, the isolation region, and the low-voltage region are sequentially arranged in the housing along a first direction, dividing the interior of the housing into three parts. A first circuit board is arranged in the high-voltage region, and a second circuit board is arranged in the low-voltage region. Components in the high-voltage component are arranged on the surface of the first circuit board, and components in the low-voltage component are arranged on the surface of the second circuit board.

[0034] The first circuit board and the second circuit board are parallel to the bottom plate of the housing and have a first predetermined distance between them.

[0035] The outer casing includes a bottom plate, a top plate, a first side plate, a second side plate, a third side plate, and a fourth side plate. The first side plate, the second side plate, the third side plate, and the fourth side plate are arranged sequentially on the four sides of the bottom plate. The first side plate and the third side plate are arranged opposite each other, the second side plate and the fourth side plate are arranged opposite each other, and the top plate and the bottom plate are arranged opposite each other. The bottom plate, the top plate, the first side plate, the second side plate, the third side plate, and the fourth side plate form a sealed space for sequentially placing the high-voltage component, the isolation component, and the low-voltage component.

[0036] In one specific embodiment of this application, the length of the first circuit board along the second direction is equal to the length of the enclosed space along the second direction, the length of the second circuit board along the second direction is equal to the length of the enclosed space along the second direction, and the second direction is perpendicular to the first direction.

[0037] In another specific embodiment of this application, a power element is disposed on the lower surface of the first circuit board, and a first heat sink is disposed on the power element. The first heat sink isolates the high-voltage area into an upper part and a lower part, and the upper part and the lower part are sealed and isolated to ensure that the main cooling channel and the auxiliary cooling channel are not connected. A power element is disposed on the lower surface of the second circuit board, and a second heat sink is disposed on the power element. The second heat sink isolates the low-voltage area into an upper part and a lower part, and the upper part and the lower part are sealed and isolated to ensure that the main cooling channel and the auxiliary cooling channel are not connected.

[0038] The first and second radiators are located in the main cooling channel.

[0039] The main cooling channel is formed in the area between the bottom plate of the outer casing and the lower part of the first heat sink, inside the isolation area, and in the area between the bottom plate of the outer casing and the lower part of the second heat sink.

[0040] Auxiliary cooling channels are formed in the area between the top plate of the outer casing and the upper part of the first heat sink, the area between the outside of the isolation area and the top plate, and the area between the top plate of the outer casing and the upper part of the second heat sink.

[0041] The surface of the first circuit board is used to house high-voltage components, the isolation area is used to house isolation components, the surface of the second circuit board is used to house low-voltage components, and the main cooling channel and auxiliary cooling channel are used for cooling gas flow. When the cooling gas flows through the channels, it carries away the heat generated by the high-voltage components, isolation components and low-voltage components during operation.

[0042] A high-pressure space is formed between the high-pressure area and the first part of the outer shell; an isolation space is formed between the isolation area and the bottom plate and two opposite side plates of the second part of the outer shell; and a low-pressure space is formed between the low-pressure area and the third part of the outer shell.

[0043] An isolation component is installed inside the isolation area. The isolation area includes an isolation frame and a shielding plate. The isolation frame is used to isolate the isolation component from the high-voltage component and the low-voltage component. The isolation frame includes three isolation plates. The first isolation plate is located between the high-voltage component and the isolation component. The second isolation plate is located between the low-voltage component and the isolation component. The third isolation plate is located above the first and second isolation plates and is used to connect the first and second isolation plates to form the isolation frame. An isolation space is formed between the isolation frame and the bottom plate of the outer shell of the isolation area, the first side plate, and the third side plate.

[0044] The lengths of the first, second, and third isolation plates along the second direction are equal to the lengths of the interior of the outer shell along the second direction.

[0045] There is a second predetermined distance between the third isolation plate and the top plate of the outer casing. The second predetermined distance creates a gap between the third isolation plate and the top plate of the outer casing to form an auxiliary cooling channel.

[0046] The first isolation plate is fixedly connected to the first circuit board and is perpendicular to the first circuit board; the second isolation plate is fixedly connected to the second circuit board and is perpendicular to the second circuit board.

[0047] A first shielding plate is provided between the first isolation plate and the isolation assembly. The first shielding plate is perpendicular to and parallel to the third isolation plate, and is fixedly connected to the first isolation plate. The first edge of the first shielding plate is fixed to the third isolation plate, and its third edge does not extend beyond the first circuit board. A second shielding plate is provided between the second isolation plate and the isolation assembly. The second shielding plate is perpendicular to and parallel to the third isolation plate, and is fixedly connected to the second isolation plate. The first edge of the second shielding plate is fixed to the third isolation plate, and its third edge does not extend beyond the second circuit board.

[0048] In this application, the first and third edges of the same board are arranged opposite each other, and the second and fourth edges are arranged opposite each other.

[0049] A third shielding plate and a fourth shielding plate are installed on the top plate near the isolation area. The third shielding plate is fixed on the top plate of the outer shell of the high-voltage area near the isolation area. A discharge resistor of the high-voltage component is installed on the first circuit board below the third shielding plate. The fourth shielding plate is fixed on the top plate of the outer shell of the low-voltage area. A low-voltage component is installed on the second circuit board below the fourth shielding plate.

[0050] The lengths of the first, second, third, and fourth shielding plates along the second direction are equal to the length of the interior of the outer shell along the second direction.

[0051] In one specific embodiment of this application, the isolation frame and the outer shell are made of insulating material to achieve electrical insulation isolation between the high-voltage component and the low-voltage component.

[0052] In another specific embodiment of this application, the isolation frame is the insulating shell of the transformer body. The transformer is encapsulated in the isolation frame and installed between the high-voltage component and the low-voltage component to isolate the high-voltage potential from the low-voltage potential.

[0053] In the main cooling channel, a first spoiler is provided on the bottom plate of the outer shell corresponding to the position below the first isolation plate, and a second spoiler is provided on the bottom plate of the outer shell corresponding to the position below the second isolation plate. The first spoiler and the second spoiler are symmetrically arranged.

[0054] Both the first and second spoilers have right-angled triangles in cross-section. The hypotenuse of the right-angled triangle of the first spoiler faces the first radiator, one right-angled side of the right-angled triangle of the first spoiler is close to the bottom plate of the outer casing, and the other right-angled side is aligned with the first isolation plate. The hypotenuse of the right-angled triangle of the second spoiler faces the second radiator, one right-angled side of the right-angled triangle of the second spoiler is close to the bottom plate of the outer casing, and the other right-angled side is aligned with the second isolation plate.

[0055] On the second side panel of the outer casing near the high-voltage area, an AC power input interface, a first outlet of the main cooling channel, and a first outlet of the auxiliary cooling channel are provided. The first outlet of the main cooling channel is close to the first radiator, and the first outlet of the auxiliary cooling channel is close to the top plate of the outer casing. An air intake grille is provided at the first outlet of the auxiliary cooling channel to regulate the airflow of the auxiliary cooling channel. On the fourth side panel of the outer casing near the low-voltage area, a DC power output interface, a second outlet of the main cooling channel, and a second outlet of the auxiliary cooling channel are provided. The second outlet of the main cooling channel is close to the second radiator, and the second outlet of the auxiliary cooling channel is close to the top plate of the outer casing. Sealing strips are provided on the second outlets of the main cooling channel and the second outlet of the auxiliary cooling channel for sealing connection with the air duct compartment of the converter cabinet.

[0056] In this application, the outlet is used for gas entry or exit, and the import can be converted into an outlet, and the outlet can be converted into an import.

[0057] Along the first direction of the arrangement of the high-voltage region, the isolation region, and the low-voltage region, the length of the isolation region on the base plate in the first direction meets the creepage distance requirements, ensuring that the equipotential of the high-voltage component and the equipotential of the low-voltage component are isolated from each other, and avoiding mutual influence between the two.

[0058] The high-voltage component adopts an NPC three-level and series half-bridge topology to realize cascade rectification and high-voltage high-frequency conversion of the input AC power. The isolation component uses magnetic elements to realize high-voltage and low-voltage isolation. The low-voltage component adopts an H-bridge topology to realize low-voltage high-frequency conversion and output adjustable DC power.

[0059] Specifically, the isolation component uses a transformer assembly.

[0060] In one specific embodiment of this application, the first heat sink, the transformer core lead wire, and each shielding plate are connected to the middle ground of the high-voltage component as the clamping grounding point of the cascaded power unit module, thereby reducing the floating voltage amplitude of the cascaded module and achieving electromagnetic field shielding and isolation.

[0061] In another specific embodiment of this application, a series resistor is connected in parallel between the two output terminals of the high-voltage component, and the midpoint of the series resistor is used as the midpoint clamping ground point to reduce the floating voltage amplitude and the isolation voltage level of the control circuit.

[0062] In a cascaded high-voltage isolated heat dissipation integrated power unit module of this application, a main cooling channel and an auxiliary cooling channel are provided. The main cooling channel is located at the bottom of the module and adopts a series channel design. Due to the high-voltage and high-frequency operating parameters, the high-voltage components have large heat losses. The first heat sink for dissipating heat from the high-voltage components is located at the front of the main cooling channel. The transformer itself has a high temperature resistance and is located in the middle of the main cooling channel. Due to the low-voltage output, the low-voltage components have small heat losses. The second heat sink for dissipating heat from the high-voltage components is located at the rear of the main cooling channel. At the same time, considering that the insulated encapsulated transformer can only dissipate heat through the surface, resulting in low heat dissipation efficiency, a first baffle and a second baffle are designed at the channel position of the isolation area where the isolation components are located in the main channel to improve the heat dissipation efficiency of the transformer. The design of the main cooling channel can ensure the heat dissipation of the power circuit heat source and the gradient control of temperature. The power supply and driver chips located in the control circuit inside the power unit will also generate a certain amount of heat loss. The auxiliary cooling channel designed on the basis of the main cooling channel is located on the top of the module. An adjustable air intake grid is set at the inlet of the auxiliary cooling channel, which can adjust the flow rate according to the temperature detection of the control circuit, thereby controlling the heat dissipation and temperature control of the circuit. The main cooling channel and the auxiliary cooling channel are sealed and isolated to avoid mutual temperature influence.

[0063] The air outlet of the integrated cooling channel is equipped with a sealing strip for the main cooling channel and auxiliary cooling channel inside the module, which are sealed to the air duct compartment of the converter cabinet.

[0064] The electromagnetic field shielding and suspension potential clamping design in this application allows for the configuration of different shielding materials according to the interference spectrum.

[0065] Example 2

[0066] The embodiments of the present invention are a detailed description of the above-described Embodiment 1, see [link to Embodiment 1]. Figures 1 to 3 .

[0067] This application discloses a cascaded high-voltage isolated heat dissipation integrated power unit module, comprising: a high-voltage component, an isolation component, a low-voltage component, and a housing. The upper surface of a first circuit board houses the control element of the high-voltage component, and its lower surface houses the power element of the high-voltage component. The power element is connected to a first heat sink for heat dissipation. The interior area of ​​the housing containing the high-voltage component is the high-voltage region. The upper surface of a second circuit board houses the control element of the low-voltage component, and its lower surface houses the power element of the low-voltage component. A second heat sink is connected to the power element for heat dissipation. The interior area of ​​the housing containing the low-voltage component is the low-voltage region. The housing encloses the power unit.

[0068] An isolation frame, including a first isolation plate, a second isolation plate, and a third isolation plate, is set around the isolation component. A first shielding plate is set between the first isolation plate and the isolation component, and a second shielding plate is set between the second isolation plate and the isolation component. The first isolation plate, the first shielding plate, the second shielding plate, and the second isolation plate are arranged sequentially and parallel to each other. The bottom edge of the first shielding plate is higher than the first circuit board, and the bottom edge of the second shielding plate is higher than the second circuit board.

[0069] The first shielding plate is fixed to the first isolation plate, and the second shielding plate is fixed to the second isolation plate.

[0070] The top edges of the first and second isolation plates are connected to a third isolation plate. The first isolation plate, the second isolation plate, the third isolation plate, the first side plate of the outer shell, the third side plate of the outer shell, and the bottom plate of the outer shell form an isolation space, and the isolation components are set in the isolation space.

[0071] There is a set distance between the third isolation plate and the top plate of the outer casing. The existence of this distance creates a gap between the third isolation plate and the top plate of the outer casing, which is used to form part of the auxiliary cooling channel.

[0072] A first spoiler is provided on the bottom plate of the outer casing at the position corresponding to the first isolation plate, and the first spoiler extends from the first side of the outer casing to the second side of the outer casing; a second spoiler is provided on the bottom plate of the outer casing at the position corresponding to the second isolation plate, and the second spoiler extends from the first side of the outer casing to the second side of the outer casing.

[0073] The first spoiler and the second spoiler have the same structure and are arranged opposite to each other. The arrangement of them opposite to each other is that a vertical line is set in the middle of the line connecting the cross-section of the first spoiler and the cross-section of the second spoiler, and the first spoiler and the second spoiler are mirror images of each other with the vertical line as the center.

[0074] The first spoiler has a right-angled triangle cross-section, with the hypotenuse facing the first radiator and the first right-angled side in close contact with the bottom plate of the outer casing. The hypotenuse of the second spoiler cross-section faces the second radiator.

[0075] A fourth isolation plate is set between the first spoiler and the second spoiler, close to the bottom plate of the outer shell, and the isolation component is fixedly set on the fourth isolation plate.

[0076] The second side panel of the housing is located on the side closer to the first circuit board, and the fourth side panel of the housing is located on the side closer to the second circuit board.

[0077] The first side panel of the outer shell is opposite to the third side panel, and the second side panel is opposite to the fourth side panel.

[0078] The main cooling inlet is located on the second side panel of the outer casing, near the first radiator. The main cooling outlet is located on the fourth side panel of the outer casing, near the second radiator. An auxiliary cooling inlet is located on the second side panel of the outer casing, near the top panel. An auxiliary cooling outlet is located on the fourth side panel of the outer casing, near the top panel. The terms "inlet" and "outlet" are relative and interchangeable, but the main cooling inlet and auxiliary cooling inlet are located on the same side panel of the outer casing, which will not be elaborated further.

[0079] The first radiator divides the high-pressure area into an upper and lower section, which are sealed and isolated from each other; the second radiator divides the low-pressure area into an upper and lower section, which are sealed and isolated from each other.

[0080] The space below the high-pressure area where the first radiator is located, the isolation space, and the space below the low-pressure area where the second radiator is located form the main cooling channel. The main cooling inlet and the main cooling outlet are located at both ends of the main cooling channel.

[0081] The space above the high-voltage area where the first circuit board is located, the space between the first side plate, the third side plate, and the top plate of the outer casing forms the first auxiliary cooling space. The space above the low-voltage area where the second circuit board is located, the space between the first side plate, the third side plate, and the top plate of the outer casing forms the second auxiliary cooling space. The first auxiliary cooling space, the gap between the outside of the isolation space and the top plate of the outer casing, and the second auxiliary cooling space form an auxiliary cooling channel. The auxiliary cooling inlet and the auxiliary cooling outlet are located at both ends of the auxiliary cooling channel.

[0082] An intake grille is installed on the auxiliary cooling inlet to regulate the airflow in the auxiliary cooling channel.

[0083] Specifically, the insulating shell structure is as follows: Figure 1 As shown, it is a cuboid, and the outer shell includes a bottom plate, a top plate, and a first side plate, a second side plate, a third side plate, and a fourth side plate. The first side plate, the second side plate, the third side plate, and the fourth side plate are arranged sequentially on the four sides of the bottom plate, and also on the four sides of the top plate. The first side plate and the third side plate are arranged opposite each other, the second side plate and the fourth side plate are arranged opposite each other, and the top plate and the bottom plate are arranged opposite each other, forming a space. The high-voltage component, the isolation component, and the low-voltage component are arranged in the space.

[0084] In this diagram, 1 is a front view of the casing, corresponding to the top plate of the casing; 2 is a side view of the casing, corresponding to the first side plate of the casing; 3 is a left view of the casing, corresponding to the second side plate of the casing. A main cooling inlet 31 is provided on the second side plate at the position corresponding to the first radiator, and an auxiliary cooling inlet 32 ​​is provided on the second side plate near the top plate of the casing. A high-voltage input interface 33 is also provided on the second side plate. 4 is a right view of the casing, corresponding to the fourth side plate of the casing. A main cooling outlet 41 is provided on the fourth side plate at the position corresponding to the second radiator, and an auxiliary cooling outlet 42 is provided on the fourth side plate near the top plate of the casing. A low-voltage output interface 43 is also provided on the fourth side plate.

[0085] like Figure 2 , Figure 3 As shown, where, Figure 2 The front sectional view of the module is shown below. After removing the top plate of the outer casing, the front section AA is visible. A first isolation plate 8 is set between the first circuit board 7 and the isolation assembly, and a second isolation plate 9 is set between the isolation assembly and the second circuit board 10. The first isolation plate 8 is vertically fixed to the first circuit board 7 and connected to the first side plate 2 and the third side plate 5 of the outer casing. The second isolation plate 9 is vertically fixed to the second circuit board 10 and connected to the first side plate 2 and the third side plate 5 of the outer casing. The first side plate 2 and the third side plate 5 are arranged opposite each other.

[0086] In one specific embodiment of this application, the length of the first circuit board 7 in the width direction of the outer casing is equal to the width of the inner casing, and the length of the second circuit board 10 in the width direction of the outer casing is equal to the width of the inner casing. That is, the first circuit board 7 is in close contact with the first side and the third side of the outer casing, respectively, and the second circuit board 10 is in close contact with the first side and the third side of the outer casing, respectively.

[0087] A high-voltage component is disposed on the surface of the first circuit board 7, including: power transistors Q1 to Q8, power transistors T1 to T4, and diodes D1 to D4. The power transistors Q1 to Q8 and diodes D1 to D4 are disposed near the third side plate of the outer casing, and the power transistors T1 to T4 are disposed near the isolation area. A discharge resistor is disposed at the position closest to the isolation area, which is not shown in the figure.

[0088] Low-voltage components, including rectifier power transistors V1 to V4, are disposed on the surface of the second circuit board 10.

[0089] The length of the isolation zone along the long side of the outer casing meets the creepage distance requirements.

[0090] Section BB perpendicular to section AA, such as Figure 3As shown, the first heat sink 19 is located in the main cooling channel, the first circuit board 7 is located above the first heat sink 19, the high voltage component is disposed on the surface of the first circuit board 7, and the area of ​​the first heat sink 19 and the top plate 1 of the outer casing forms an auxiliary cooling channel.

[0091] A first isolation plate 8 is fixedly connected to the first circuit board 7 near the isolation area. The first isolation plate 8 is perpendicular to the first circuit board 7. A first baffle 14 is provided on the bottom plate 6 of the outer casing at a position corresponding to the first isolation plate 8. The cross-section of the first baffle 14 is a right-angled triangle, with the hypotenuse of the right-angled triangle facing the first heat sink 19. One right-angled side is in close contact with the bottom plate of the outer casing, and the other right-angled side is aligned with the first isolation plate 8. A first distance is provided between the highest point of the cross-section of the first baffle 14 and the first side of the first isolation plate 8 to ensure unobstructed airflow in the main cooling channel.

[0092] The first shielding plate 12 is fixed on the first isolation plate 8. The first edge of the first shielding plate 12 is fixedly connected to the third isolation plate 21. The third edge of the first shielding plate 12 is opposite to the first edge. The third edge of the first shielding plate 12 does not extend beyond the first isolation plate. That is, the length of the first shielding plate 12 in the width direction of the outer shell is less than or equal to the length of the first isolation plate in the same direction.

[0093] Similarly, the second shielding plate 13 is fixed on the second isolation plate 9. The first edge of the second shielding plate 13 is fixedly connected to the third isolation plate 21. The third edge of the second shielding plate 13 is opposite to the first edge. The third edge of the second shielding plate 13 does not extend beyond the second isolation plate 9. That is, the length of the second shielding plate 13 in the width direction of the outer shell is less than or equal to the length of the second isolation plate in the same direction.

[0094] A second baffle 15 is provided at the position corresponding to the bottom plate 6 of the outer casing and the second isolation plate 9. The cross-section of the second baffle 15 is a right-angled triangle, with the hypotenuse of the right-angled triangle facing the second heat sink 11. One right-angled side is in close contact with the bottom plate of the outer casing, and the other right-angled side is aligned with the second isolation plate 9. A first distance is provided between the highest point of the cross-section of the second baffle 15 and the first side of the second isolation plate 9 to ensure unobstructed airflow in the main cooling channel.

[0095] An isolation pad 20 is provided between the first spoiler 14 and the second spoiler 15, and an isolation transformer is fixed on the isolation pad 20. The distance between the first spoiler 14 and the second spoiler 15 meets the creepage requirements and is used to isolate the electrical requirements between the high-voltage components and the low-voltage components.

[0096] The first edge of the third isolation plate 21 is fixedly connected to the first isolation plate 8. The third edge of the third isolation plate 21, which is opposite to the first edge, is fixedly connected to the second isolation plate 9. There is a set distance between the third isolation plate 21 and the top plate 1 of the outer shell, forming a gap 16, which is used to form part of the auxiliary cooling channel.

[0097] An isolation component—a transformer assembly—is installed in the isolation space formed by the third isolation plate 21, the first isolation plate 8, and the second isolation plate 9.

[0098] A third shielding plate 17 is provided on the top plate 1 of the outer casing near the isolation area in the high-voltage area. A discharge resistor is provided on the first circuit board 7 below the third shielding plate 17. A fourth shielding plate 18 is provided on the top plate 1 of the outer casing near the isolation area in the low-voltage area. A low-voltage component is provided on the second circuit board 10 below the fourth shielding plate 18.

[0099] The high-voltage component equipotential region is placed on the left side of the module, and the low-voltage component equipotential region is placed on the right side of the module. The outer shell of the transformer body adopts the insulating material mold opening and potting process and is installed in the magnetic element isolation area between the high-voltage and low-voltage component equipotential regions. The high-voltage component equipotential region and the low-voltage component equipotential region are ensured by the insulating shell of the transformer component isolation area to ensure the corresponding electrical and creepage distances, thereby realizing the insulation design of the high-voltage and low-voltage components of the module on the potential difference.

[0100] Example 3

[0101] The embodiments of the present invention are a detailed description of the above-described Example 1.

[0102] The power unit circuit topology of a cascaded high-voltage isolation and heat dissipation integrated power unit module of this application is as follows: Figure 4 As shown.

[0103] It includes: a high-voltage component section, a magnetic component section, and a low-voltage component section connected in sequence. The high-voltage component section includes an NPC three-level circuit and a series half-bridge circuit. The NPC three-level circuit includes power transistors Q1 to Q8 and diodes D1 to D4. Power transistors Q1, Q2, Q3, and Q4 are connected in series in sequence, as are power transistors Q5, Q6, Q7, and Q8. The output terminals of power transistors Q1 and Q5 are connected together as the positive output terminal of the NPC three-level circuit. The output terminals of power transistors Q4 and Q8 are connected together as the negative output terminal of the NPC three-level circuit. The connection point between the input terminals of power transistors Q2 and Q3 is connected to one input terminal of the AC power supply, and the connection point between the input terminals of power transistors Q6 and Q7 is connected to the other input terminal of the AC power supply.

[0104] The cathode of diode D1 is connected to the anode of diode D2 and serves as the intermediate ground terminal; the connection point between the output terminal of power transistor Q3 and the input terminal of power transistor Q4 is connected to the anode of diode D2, and the connection point between the output terminal of power transistor Q2 and the input terminal of power transistor Q2 is connected to the cathode of diode D1.

[0105] The cathode of diode D4 is connected to the anode of diode D3 and serves as the intermediate ground terminal; the connection point between the output terminal of power transistor Q7 and the input terminal of power transistor Q8 is connected to the anode of diode D4, and the connection point between the output terminal of power transistor Q6 and the input terminal of power transistor Q5 is connected to the cathode of diode D3.

[0106] A capacitor C1 is connected in parallel between the positive output terminal and the intermediate ground terminal of the NPC three-level circuit for filtering. A capacitor C2 is connected in parallel between the negative output terminal and the intermediate ground terminal of the NPC three-level circuit for filtering. The discharge resistor R1 is connected in parallel with the capacitor C1, and the discharge resistor R2 is connected in parallel with the capacitor C2.

[0107] The series half-bridge circuit includes: power transistors T1 to T4 connected in series. The input terminal of power transistor T1 is connected to the positive output terminal of the NPC three-level circuit. The output terminal of power transistor T1 is connected to the input terminal of power transistor T2 and one end of capacitor Cr. The other end of capacitor Cr serves as one output terminal of the series half-bridge circuit and is connected to one input terminal of the magnetic element.

[0108] The output terminal of power transistor T2 is connected to the input terminal and intermediate ground terminal of power transistor T3. The output terminal of power transistor T3 is connected to the input terminal of power transistor T4, and serves as the other output terminal of the series half-bridge circuit, which is connected to the other input terminal of the magnetic component. The output terminal of power transistor T3 is connected to the negative output terminal of the NPC three-level circuit.

[0109] The magnetic core of the magnetic component is connected to the intermediate ground terminal. At the same time, the first heat sink, the second heat sink, and all shielding plates are also connected to the intermediate ground terminal.

[0110] The magnetic components include a transformer and an LLC circuit. An inductor Lm is connected in parallel between the two leads of the primary coil of the transformer. One lead of the transformer is connected to one end of the inductor Lr, and the other end of the inductor Lr is connected to the other end of the capacitor Cr. The other lead of the transformer is connected to the output terminal of the power transistor T3 and the input terminal of the power transistor T4.

[0111] One lead of the transformer secondary coil is connected to one input terminal of the H-bridge rectifier circuit, and its other lead is connected to the other input terminal of the H-bridge rectifier circuit through capacitor C4. The input terminal of power terminal V1 in the H-bridge rectifier circuit is connected to the input terminal of power terminal V2 and serves as one input terminal of the H-bridge rectifier circuit. The input terminal of power terminal V3 is connected to the input terminal of power terminal V4 and serves as the other input terminal of the H-bridge rectifier circuit. The output terminal of power terminal V1 is connected to the output terminal of power terminal V3 and one end of filter capacitor Cb and serves as one output terminal of the H-bridge rectifier circuit. The output terminal of power terminal V2 is connected to the output terminal of power terminal V4 and the other end of filter capacitor Cb and serves as the other output terminal of the H-bridge rectifier circuit.

[0112] Isolation transformers are installed between high-voltage and low-voltage components to achieve the isolation requirements of high voltage in the power grid.

[0113] In this embodiment, the power unit module is treated as a branch, and multiple branches are cascaded, such as... Figure 5 As shown, the AC input terminals of the high-voltage components are connected in series to match different AC input voltages, while the DC output terminals of the low-voltage components can be connected in parallel to output different DC currents, thus expanding the output power. This enables grid connection of three-phase or single-phase power grids with different voltage levels. The low-voltage DC side is output from multiple branches in parallel. Each cascaded branch is internally constructed with rectifier and high-frequency DC-DC isolation conversion circuits. The cascaded high-voltage isolation and integrated heat dissipation power unit module is based on the cascaded branch functional circuits, further integrating key components such as heat sinks, magnetic components, and controllers into a standardized power unit module design.

[0114] It should be understood that the terms "mechanism," "device," "component," etc., used in this application are merely one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they can be replaced by other expressions.

[0115] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention. In practical applications, the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification, and various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A cascaded high-voltage isolated heat dissipation integrated power unit module, characterized in that, include: The housing, the high-voltage area containing the high-voltage components, the isolation area containing the isolation components, and the low-voltage area containing the low-voltage components are arranged sequentially within the housing. The high-voltage area is equipped with a first circuit board, the surface of which is used to mount the high-voltage components. The isolation area is used to mount the isolation components. The low-voltage area is equipped with a second circuit board, the surface of which is used to mount the low-voltage components. A main cooling channel is formed in the area between the bottom plate of the housing and the lower part of the first circuit board, inside the isolation area, and between the bottom plate of the housing and the lower part of the second circuit board, for the flow of cooling gas to dissipate heat from the high-voltage components, the isolation components, and the low-voltage components.

2. The cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 1, characterized in that, It also includes auxiliary cooling channels, which are formed in the area between the top plate of the housing and the upper part of the first circuit board, the area between the outside of the isolation area and the top plate of the housing, and the area between the top plate of the housing and the upper part of the second circuit board, for the flow of cooling gas to dissipate heat from the high-voltage components, the isolation components and the low-voltage components.

3. A cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 1 or 2, characterized in that, The isolation area is provided with an isolation frame. The isolation frame, together with the bottom plate of the outer shell, the first side plate of the outer shell, and the third side plate of the outer shell, forms an isolation space. The isolation component is set in the isolation space, and the isolation frame is set between the high-voltage area and the low-voltage area for insulation isolation between the high-voltage component, the isolation component, and the low-voltage component. A main cooling channel is formed in the area between the bottom plate of the outer casing and the lower part of the first circuit board, the area inside the isolation frame, and the area between the bottom plate of the outer casing and the lower part of the second circuit board. The top of the isolation frame is at a set distance from the top plate of the outer casing, forming a gap area between the top of the isolation frame and the top plate of the outer casing, and forming an auxiliary cooling channel between the area between the top plate of the outer casing and the upper surface of the first circuit board, the gap area, and the area between the top plate of the outer casing and the upper surface of the second circuit board. The first side panel of the outer casing is positioned opposite to the third side panel of the outer casing.

4. The cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 3, characterized in that, The isolation frame includes a first isolation plate, a second isolation plate, and a third isolation plate. The first side of the first isolation plate is connected to a first circuit board, the first side of the second isolation plate is connected to a second circuit board, the third side of the first isolation plate is connected to the first side of the third isolation plate, and the third side of the second isolation plate is connected to the third side of the third isolation plate. The first isolation plate, the second isolation plate, the third isolation plate, the bottom plate of the outer shell, the first side plate of the outer shell, and the third side plate of the outer shell form an isolation space. The isolation space is used to set up isolation components. The third isolation plate is the top plate of the isolation frame. The first side and the third side of the same plate are arranged opposite to each other, and the first side plate and the third side plate of the outer shell are arranged opposite to each other.

5. A cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 4, characterized in that, The isolation area is also provided with a shielding plate. The first shielding plate is disposed between the first isolation plate and the isolation component, and the second shielding plate is disposed between the second isolation plate and the isolation component. The first side of the first shielding plate and the first side of the second shielding plate are connected to the third isolation plate. The first shielding plate is fixedly connected to the first isolation plate, and the third side of the first shielding plate does not extend beyond the first side of the first isolation plate. The second shielding plate is fixedly connected to the second isolation plate, and the third side of the second shielding plate does not extend beyond the first side of the second isolation plate.

6. A cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 1, characterized in that, The first circuit board has a first heat sink at its lower part, which is used to dissipate heat from the power devices in the high-voltage component. The second circuit board has a second heat sink at its lower part, which is used to dissipate heat from the power devices in the low-voltage component. The first heat sink and the second heat sink are located in the main cooling channel.

7. A cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 1, characterized in that, The first radiator is sealed to the side panel of the outer casing, which is used to separate the high-pressure area into an upper and lower part, and the upper and lower parts are not connected. The gas in the main cooling channel does not enter the auxiliary cooling channel. The second radiator is sealed to the side panel of the outer casing, which is used to separate the low-pressure area into an upper and lower part, and the upper and lower parts are not connected. The gas in the main cooling channel does not enter the auxiliary cooling channel.

8. A cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 1, characterized in that, The main cooling channel is equipped with a baffle plate. The first baffle plate is located on the bottom plate of the outer shell below the first isolation plate, and the second baffle plate is located on the bottom plate of the outer shell below the second isolation plate. The first baffle plate and the second baffle plate are symmetrically arranged. The distance between the first baffle plate and the second baffle plate can meet the creepage requirements. An isolation pad is set between the first baffle plate and the second baffle plate, and the isolation component is fixedly set on the isolation pad.

9. A cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 8, characterized in that, The first and second spoilers have the same structure, with a right-angled triangle cross-section. The hypotenuse of the right-angled triangle of the first spoiler faces the first radiator in the main cooling channel. A first distance is provided between the highest point of the cross-section of the first spoiler and the first side of the first isolation plate. A first distance is also provided between the highest point of the cross-section of the second spoiler and the first side of the second isolation plate.

10. A cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 1, characterized in that, The outer casing is insulated and includes a bottom plate, a top plate, and first to fourth side plates. The bottom plate has a first side plate, a second side plate, a third side plate, and a fourth side plate on its four sides. The top plate is opposite to the bottom plate, the first side plate is opposite to the third side plate, and the second side plate is opposite to the fourth side plate. The second side plate is located on the high-voltage component side, and the fourth side plate is located on the low-voltage component side. A first opening of the main cooling channel is provided on the second side plate near the main cooling channel. A first opening of the auxiliary cooling channel is provided on the second side plate near the top plate of the casing. A second opening of the main cooling channel is provided on the fourth side plate near the main cooling channel. A second opening of the auxiliary cooling channel is provided on the second side plate near the top plate.

11. A cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 10, characterized in that, The first opening of the auxiliary cooling channel is provided with a grid to control the air intake of the auxiliary cooling channel. The second opening of the main cooling channel is provided with a first sealing strip, and the second opening of the auxiliary cooling channel is provided with a second sealing strip for sealing connection with external equipment.

12. A cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 1, characterized in that, The power unit circuit includes a high-voltage component, an isolation component, and a low-voltage component connected in sequence. The high-voltage component includes an NPC three-level circuit, a discharge resistor, and a series half-bridge topology for cascade rectification and high-voltage high-frequency conversion. The isolation component includes magnetic elements for high-voltage and low-voltage isolation. The low-voltage component includes an H-bridge topology for low-voltage high-frequency conversion and output DC voltage.

13. A cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 12, characterized in that, A third shielding plate is provided on the top plate of the housing corresponding to the position of the discharge resistor, and is fixedly connected to the top plate of the housing. A fourth shielding plate is provided on the top plate of the housing corresponding to the position of the low-voltage component, and is fixedly connected to the top plate of the housing.

14. A cascaded high-voltage isolated heat dissipation integrated power unit module according to claim 12, characterized in that, The transformer core, first heat sink, second heat sink, and all shielding plates in the isolation assembly are connected to the intermediate ground terminal of the high-voltage assembly as a clamping grounding point.

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