CN116760305B

CN116760305B - Three-level converter system

Info

Publication number: CN116760305B
Application number: CN202310639474.XA
Authority: CN
Inventors: 张东胜; 韩永; 包梦宇; 姜淳琳; 许玉林
Original assignee: New Dynamic Beijing Smart Energy Technology Co ltd
Current assignee: New Dynamic Beijing Smart Energy Technology Co ltd
Priority date: 2023-05-31
Filing date: 2023-05-31
Publication date: 2024-01-26
Anticipated expiration: 2043-05-31
Also published as: CN116760305A

Abstract

Embodiments of the present disclosure provide a three-level converter system, including: a first printed circuit board; a plurality of heat sinks arranged perpendicular to the first surface of the first printed circuit board; and a multiphase three level active neutral point clamped converter circuit. Each heat sink extends in a first direction. The plurality of heat sinks are arranged in parallel along the second direction. Every two adjacent radiators form a radiator pair. Each phase leg includes at least two single-phase three-level active neutral point clamped converter circuits. Each single-phase three-level active neutral point clamped converter circuit includes an upper leg and a lower leg. The power devices in the upper leg are disposed in parallel on the first printed circuit board in a first direction against a first side of a first heat sink in the pair of heat sinks. The power devices in the lower leg are arranged in parallel on the first printed circuit board in the first direction against the second side of the second heat sink in the pair of heat sinks.

Description

Three-level converter system

Technical Field

Embodiments of the present disclosure relate to the field of circuit technology, and in particular, to a three-level converter system.

Background

Active neutral point clamped (active neutral point clamped, ANPC) converter circuits are widely used in electronic power converters. The ANPC converter circuit may be implemented as an integrated circuit or as a discrete device. In high power applications, the integrated circuit type ANPC converter is relatively concentrated in heat, is prone to damage to power devices, and has a higher cost than a discrete device type ANPC converter. The arrangement of the discrete device ANPC converter is more flexible, but the volume of the discrete device ANPC converter is larger relative to the integrated circuit type ANPC converter. If it is desired to reduce the volume of the discrete-device ANPC converter, its heat dissipation may be affected. Therefore, how to rationally design a discrete device type ANPC converter is a direction of research.

Disclosure of Invention

Embodiments described herein provide a three level converter system.

According to a first aspect of the present disclosure, a three-level converter system is provided. The three-level converter system includes: a first Printed Circuit Board (PCB); a plurality of heat sinks arranged perpendicular to the first surface of the first printed circuit board; and a multiphase three level active neutral point clamped converter circuit. Wherein each heat sink extends in a first direction. The plurality of heat sinks are arranged in parallel along the second direction. Every two adjacent radiators form a radiator pair. The second direction is perpendicular to the first direction. The plane formed by the first direction and the second direction is parallel to the first surface of the first printed circuit board. Each phase leg of the multiphase three level active neutral point clamped converter circuit includes at least two single phase three level active neutral point clamped converter circuits. Each single-phase three-level active neutral point clamped converter circuit includes an upper leg and a lower leg. The power devices in the upper leg are disposed in parallel on the first printed circuit board in a first direction against a first side of a first heat sink in the pair of heat sinks. The power devices in the lower leg are arranged in parallel on the first printed circuit board in the first direction against the second side of the second heat sink in the pair of heat sinks. The first side is disposed opposite the second side.

In some embodiments of the present disclosure, each phase leg in the multiphase three level active neutral point clamped converter circuit further comprises at least two first inductors. The output of each single-phase three-level active neutral point clamped converter circuit is coupled to a first end of a first inductor. The second ends of the at least two first inductors are coupled to each other. The first inductor is disposed on an extension of the first heat sink in the first direction and near a first end of the first heat sink.

In some embodiments of the present disclosure, the three-level converter system further comprises: and a second printed circuit board. The second printed circuit board has a filter circuit disposed thereon. The filtering circuit is configured to filter the current output from the first inductor. Wherein the first inductor is arranged between the first printed circuit board and the second printed circuit board.

In some embodiments of the present disclosure, the three-level converter system further comprises: and a second printed circuit board. The second printed circuit board has a filter circuit disposed thereon. The filtering circuit is configured to filter the current output from the first inductor. Wherein the first inductor is arranged below the second printed circuit board.

In some embodiments of the present disclosure, the three-level converter system further comprises: a main control board arranged perpendicular to the first surface of the first printed circuit board. The main control board is disposed at a first edge of the first printed circuit board. The main control board is used for controlling the output current and the output voltage of the multiphase three-level active neutral point clamping type converter circuit and controlling the working state of the three-level converter system.

In some embodiments of the present disclosure, the multiphase three level active neutral point clamped converter circuit further comprises: at least one first dc bus capacitor and at least one second dc bus capacitor disposed on the first printed circuit board. The first DC bus capacitor is coupled between the positive voltage potential terminal and the neutral voltage potential terminal. The second DC bus capacitor is coupled between the negative voltage potential terminal and the neutral voltage potential terminal.

In some embodiments of the present disclosure, a capacitor having a large capacitance value of the first and second dc bus capacitors is disposed on an extension of the first heat sink in the first direction and near the second end of the first heat sink.

In some embodiments of the present disclosure, a capacitor of the first and second dc bus capacitors having a small capacitance value is disposed in a gap between the first and second heat sinks and near the second end of the first heat sink.

In some embodiments of the present disclosure, the three-level converter system further comprises a cooling air input port. The cooling air input port is arranged such that externally input cooling air flows in a first direction from the second end of the first heat sink to the first end of the first heat sink.

In some embodiments of the present disclosure, the three-level converter system further comprises a snubber circuit disposed on the first printed circuit board. The snubber circuit includes a capacitor bank and a resistor bank connected in series with each other. The capacitor bank includes a plurality of capacitors connected in series and parallel to each other. The resistor group includes a plurality of resistors connected in series and parallel to each other. The absorption circuit is coupled between the midpoint of the upper bridge arm and the midpoint of the lower bridge arm. The snubber circuit is configured to suppress overvoltage occurrence in power devices in the multiphase three level active neutral point clamped converter circuit. The absorption circuit is disposed in a gap between the first heat sink and the second heat sink and near a first end of the first heat sink.

In some embodiments of the present disclosure, the three-level converter system further comprises a drive circuit. The driving circuit is disposed on a second surface of the first printed circuit board opposite to the first surface. The drive circuit is configured to drive power devices in the multiphase three level active neutral point clamped converter circuit.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following brief description of the drawings of the embodiments will be given, it being understood that the drawings described below relate only to some embodiments of the present disclosure, not to limitations of the present disclosure, in which:

FIG. 1 is an exemplary circuit diagram of a single phase leg in a multiphase three level active neutral point clamped converter circuit in accordance with an embodiment of the present disclosure;

FIG. 2 is an exemplary circuit diagram of an absorption circuit for the upper leg shown in FIG. 1;

FIG. 3 is a top view of a three-level converter system according to an embodiment of the disclosure; and

fig. 4 is a cross-sectional view of a three-level converter system according to an embodiment of the disclosure.

It is noted that the elements in the drawings are schematic and are not drawn to scale.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings. It will be apparent that the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments, which can be made by those skilled in the art based on the described embodiments of the present disclosure without the need for creative efforts, are also within the scope of the protection of the present disclosure.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the presently disclosed subject matter belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. As used herein, a statement that two or more parts are "connected" or "coupled" together shall mean that the parts are joined together either directly or joined through one or more intermediate parts.

Spatially relative terms, such as "upper," "lower," "left," "right," "top," "bottom," and the like, may be used herein for ease of description to describe one device or element's spatial location relative to another device or element as illustrated in the figures. For example, the terms "on … …", "over … …", "over … …", "on … … upper surface", "above", "positioned on … …" or "positioned on top of … …" and the like mean that a first element, such as a first structure, is present on a second element, such as a second structure, wherein intermediate elements may or may not be present between the first element and the second element. The term "contacting" means connecting a first element, such as a first structure, and a second element, such as a second structure, with or without other elements at the interface of the two elements. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may also be oriented 90 degrees or at other orientations and the spatially relative descriptors used herein interpreted accordingly.

In all embodiments of the present disclosure, since the source and drain of a Metal Oxide Semiconductor (MOS) transistor are symmetrical and the on-current directions between the source and drain of an N-type transistor and a P-type transistor are opposite, in embodiments of the present disclosure, the controlled middle terminal of the MOS transistor is referred to as the control pole and the remaining two terminals of the MOS transistor are referred to as the first pole and the second pole, respectively. In addition, for convenience of unified expression, in the context, the base of a bipolar transistor (BJT) is referred to as a control electrode, the emitter of the BJT is referred to as a first electrode, and the collector of the BJT is referred to as a second electrode. In addition, terms such as "first" and "second" are used merely to distinguish one component (or portion of a component) from another component (or another portion of a component).

Fig. 1 illustrates an exemplary circuit diagram of a single-phase leg 100 in a multiphase three level Active Neutral Point Clamped (ANPC) converter circuit in accordance with an embodiment of the present disclosure. Single-phase leg 100 includes: at least two single-phase three-level ANPC converter circuits 110 (only two single-phase three-level ANPC converter circuits 110 are shown in the example of fig. 1). Each single-phase three-level ANPC converter circuit 110 includes an upper leg 111 and a lower leg 112. The output terminals PHUA1 of the upper leg 111 and the lower leg 112 are commonly coupled to a first end of a first inductor L1. The second ends of each first inductor L1 are coupled to each other and to the output end AOUT of the single-phase leg 100 in common.

The circuit configuration of the upper arm 111 and the lower arm 112 is symmetrical. The upper bridge arm 111 includes a plurality of power device units Q1, … …, Q6. Each power device cell Q1, … …, Q6 includes a transistor. A diode in parallel with the transistor is also shown in the example of fig. 1. The diode may be a body diode of a transistor. The power device units Q1 and Q2 (as a power device unit group) are connected in series between the positive voltage potential terminal dc+ and the neutral voltage potential terminal NP. The power device cells Q3 and Q4 (as another power device cell group) are also connected in series between the positive voltage potential terminal dc+ and the neutral voltage potential terminal NP. The plurality of power device unit groups are arranged between the positive voltage potential end DC+ and the neutral voltage potential end NP, so that the current of each power device unit group is smaller, and the power consumption is reduced. The power device cells Q2 and Q4 are connected in parallel. The power device cells Q2, Q4, Q5 and Q6 are commonly coupled to the node EPHA1. The power device units Q5 and Q6 are connected in parallel between the node EPHA1 and the output PHUA1 of the upper arm 111. Providing a plurality of power device units between node EPHA1 and output terminal PHUA1 of upper bridge arm 111 may enable the current of each power device unit to be smaller, thereby reducing power consumption. The transistors in the power device cells Q1, Q2, Q3, and Q4 may be Insulated Gate Bipolar Transistors (IGBTs). The transistors in the power device cells Q5 and Q6 may be implemented by third generation semiconductor materials.

In some embodiments of the present disclosure, the multiphase three level ANPC converter circuit further comprises: at least one first dc bus capacitor and at least one second dc bus capacitor. The at least one first dc bus capacitor and the at least one second dc bus capacitor are common to each phase leg in the multi-phase three-level ANPC converter circuit. In fig. 1, a first dc bus capacitor C1 and a second dc bus capacitor C2 are shown coupled to a single phase leg 100. The first DC bus capacitor C1 is coupled between the positive voltage potential terminal dc+ and the neutral voltage potential terminal NP. The second DC bus capacitor C2 is coupled between the negative voltage potential terminal DC-and the neutral voltage potential terminal NP. Only one first dc bus capacitor C1 and one second dc bus capacitor C2 are shown as examples in fig. 1. In some embodiments of the present disclosure, a plurality of first DC bus capacitors C1 may be connected in parallel between the positive voltage potential terminal dc+ and the neutral voltage potential terminal NP. A plurality of second DC bus capacitors C2 may be connected in parallel between the negative voltage potential terminal DC-and the neutral voltage potential terminal NP. The number of the first dc bus capacitor C1 and the second dc bus capacitor C2 may be set according to practical applications.

In some embodiments of the present disclosure, the multiphase three-level ANPC converter circuit is a three-phase three-level ANPC converter circuit.

In some embodiments of the present disclosure, the multiphase three level ANPC converter circuit further includes an snubber circuit. The snubber circuit is configured to suppress an overvoltage from occurring in a power device in the multiphase three level ANPC converter circuit. Fig. 2 shows an exemplary circuit diagram of a tank circuit for the single-phase three-level ANPC converter circuit 110 shown in fig. 1. The snubber circuit includes a capacitor bank and a resistor bank connected in series with each other. The capacitor bank includes a plurality of capacitors connected in series and parallel to each other. The resistor group includes a plurality of resistors connected in series and parallel to each other. The two ends of the absorption circuit are respectively coupled with the midpoint of the upper bridge arm (node EPHA 1) and the midpoint of the lower bridge arm (node EPLA 1). Node EPHA1 and node epaa 1 may also be coupled to a plurality of sink circuits as shown in fig. 2. The capacitor in the snubber circuit has a small capacitance value. In some embodiments of the present disclosure, each phase leg in a multiphase three level ANPC converter circuit may include an snubber circuit. In other embodiments of the present disclosure, a portion of the legs in a multiphase three level ANPC converter circuit may include an snubber circuit. In the example of fig. 1, node EPHA2 and node epaa 2 may also be coupled to one or more sink circuits.

In high power applications, the power consumption of the multiphase three level ANPC converter circuit is high and therefore the heat dissipation requirements are high. The use of discrete device type multiphase three-level ANPC converter circuits allows heat to be dissipated, but how to improve heat dissipation efficiency and reduce size is still a need for research.

Embodiments of the present disclosure propose a three-level converter system capable of efficiently dissipating heat and realizing a compact structure. In some embodiments of the present disclosure, the three-level converter system may be a multiphase three-level active neutral point clamped converter system. Fig. 3 illustrates a top view of a three-level converter system according to an embodiment of the disclosure. The three-level converter system includes: the multi-phase three-level ANPC converter circuit comprises a first printed circuit board PCB1, a plurality of heat sinks S arranged perpendicular to a first surface of the first printed circuit board PCB1, and a multi-phase three-level ANPC converter circuit. The three-level converter system may be arranged in a cabinet CAB.

Wherein each heat sink S extends in a first direction D1. The plurality of heat sinks S are arranged in parallel along the second direction D2 (in other words, the plurality of heat sinks S are arranged in a row in the second direction D2). The second direction D2 is perpendicular to the first direction D1. The plane formed by the first direction D1 and the second direction D2 is parallel to the first surface of the first printed circuit board PCB 1. Every two adjacent heat sinks S constitute a heat sink pair. For example, a first radiator S and a second radiator S from left to right constitute one radiator pair. The third radiator S and the fourth radiator S from left to right constitute another radiator pair. And so on. Each radiator pair includes a first radiator S and a second radiator S. The first side of the first heat sink S is arranged opposite (facing) the second side of the second heat sink S. A gap is left between the first radiator S and the second radiator S.

As shown in fig. 1, each phase leg 100 of the multiphase three-level ANPC converter circuit includes at least two single-phase three-level ANPC converter circuits 110. Each single-phase three-level ANPC converter circuit 110 includes an upper leg 111 and a lower leg 112. Each single-phase three-level ANPC converter circuit 110 corresponds to a radiator pair. The power devices (transistors in the power device units Q1, … …, Q6) in the upper leg 111 are arranged in parallel on the first printed circuit board PCB1 in the first direction D1 against the first side of the first heat sink S in the corresponding pair of heat sinks. The power devices in the lower leg 112 are arranged in parallel on the first printed circuit board PCB1 against the second side of the second heat sink S in the corresponding pair of heat sinks and along the first direction D1.

Fig. 4 illustrates a cross-sectional view of a three-level converter system along line AA' in accordance with an embodiment of the present disclosure. As can be seen from fig. 4, the power device units Q1, … …, Q6 are arranged in a row in the first direction D1 and are arranged on the first printed circuit board PCB 1. The arrangement of the power device units in fig. 4 is merely illustrative, and the embodiments of the present disclosure do not limit the arrangement sequence of the power device units Q1, … …, Q6. A gap may be provided between the first printed circuit board PCB1 and the cabinet CAB to facilitate heat dissipation.

As shown in fig. 1, each phase leg 100 in the multiphase three level ANPC converter circuit further comprises at least two first inductors L1. The output of each single-phase three-level ANPC converter circuit is coupled to a first end of a first inductor L1. The second ends of the at least two first inductors L1 are coupled to each other. In the example of fig. 3, the first inductor L1 is arranged on an extension line of the first heat sink S in the first direction D1 and near a first end (an upper one of both ends of the first heat sink S) of the first heat sink S.

In some embodiments of the present disclosure, the three-level converter system further comprises: a second printed circuit board PCB2. A filter circuit is arranged on the second printed circuit board PCB2. The filter circuit is configured to filter the current output from the first inductor L1. The filter circuit may be a conventional filter circuit. In some embodiments of the present disclosure, the first inductor L1 is arranged between the first printed circuit board PCB1 and the second printed circuit board PCB2. Considering that the first inductor L1 is heavy in weight, the first inductor L1 is not disposed on the first printed circuit board PCB1 or the second printed circuit board PCB2. Referring to fig. 4, the first inductor L1 may be directly fixed on the cabinet CAB. The first inductor L1 is connected with the single-phase three-level ANPC converter circuit through a jumper wire. The first inductor L1 is also connected to the filter circuit by a jumper. In other embodiments of the present disclosure, the first inductor L1 may be disposed under the second printed circuit board PCB2. In other words, the first inductor L1 and the second printed circuit board PCB2 are stacked in the third direction D3 shown in fig. 4, and the second printed circuit board PCB2 is stacked above the first inductor L1.

The filter circuit may include a second inductor L2, a capacitor, and a resistor. In the example of fig. 3, the three second inductors L2 on the left are ac filter inductors, and the two second inductors L2 on the right are dc filter inductors. The capacitors in the filter circuit are arranged at the locations marked C in the second printed circuit board PCB2 in fig. 3 and 4. The resistor in the filter circuit is too small and is therefore not shown in fig. 3 and 4. And a fuse F is arranged between the filter circuit and the direct current input ends IN1 and IN2 and between the filter circuit and the alternating current output ends OUT1, OUT2 and OUT3 respectively, and is used for carrying OUT overheat protection on the three-level converter system.

Referring to fig. 3, in some embodiments of the present disclosure, the three-level converter system may further include: a main control board 330 arranged perpendicular to the first surface of the first printed circuit board PCB 1. The main control board 330 is disposed at a first edge (right edge) of the first printed circuit board PCB 1. The main control board 330 is used to control the magnitude of the output current and output voltage of the multiphase three level active neutral point clamped converter circuit and to control the operating state (start and stop) of the three level converter system. A first socket 340 is also arranged at the first edge of the first printed circuit board PCB 1. The first socket 340 includes a plurality of pins coupled with a main control circuit on the main control board 330. A second socket 350 is arranged on the second printed circuit board PCB2. The second receptacle 350 includes a plurality of pins coupled to the filter circuit. The second receptacle 350 is aligned with the first receptacle 340 in the first direction D1. The second socket 350 is close to the dc input terminals IN1 and IN2 and far from the ac output terminals OUT1, OUT2 and OUT3, and thus the main control circuit is correspondingly far from the ac output terminals OUT1, OUT2 and OUT3, so that the interference can be reduced. The first socket 340 and the second socket 350 are connected in a docking manner through an external connection so that the main control circuit can control the filter circuit to work.

Also shown in the example of fig. 3 are two first DC terminals 360 (corresponding to the positive voltage potential end dc+ and the negative voltage potential end DC-) in fig. 1, respectively) located on the first printed circuit board PCB1 and two second DC terminals 370 located on the second printed circuit board PCB2. The two first dc terminals 360 and the two second dc terminals 370 may be correspondingly coupled by jumpers. The two second dc terminals 370 and the dc input terminals IN1 and IN2 may be coupled through wiring on the second printed circuit board PCB2, respectively.

As shown in fig. 1, the multiphase three level ANPC converter circuit further includes: at least one first dc bus capacitor C1 and at least one second dc bus capacitor C2. In some embodiments of the present disclosure, a capacitor having a large capacitance value among the first and second dc bus capacitors is disposed on an extension line of the first heat sink S in the first direction D1 and near the second end (lower one of both ends of the first heat sink S) of the first heat sink S. In the example of fig. 3, a capacitor having a large capacitance value among the first and second dc bus capacitors may be arranged at a position marked C on the first printed circuit board PCB 1. On the right side of the heat sink S, a first dc bus capacitor and a second dc bus capacitor may also be arranged. The capacitor having a small capacitance value among the first and second dc bus capacitors is disposed in a gap between the first and second heat sinks S and near the second end of the first heat sink S. In the example of fig. 4, a capacitor having a large capacitance value among the first and second dc bus capacitors may be arranged at positions marked as C1 and C2 on the first printed circuit board PCB 1. The capacitor having a small capacitance value among the first and second dc bus capacitors is arranged at a position aligned parallel to the power device units Q1, … …, Q4 perpendicular to the paper surface.

In some embodiments of the present disclosure, the three-level converter system further comprises a cooling air input port. The cooling air input port is arranged such that externally input cooling air flows in a first direction D1 from the second end of the first radiator S to the first end of the first radiator S (i.e., in the direction a' a in the example of fig. 4). Therefore, the cooling air firstly passes through the radiator and then passes through the first inductor L1, so that the power device can be cooled preferentially.

As described above, in some embodiments of the present disclosure, the three-level converter system may further include a snubber circuit. The absorption circuit is arranged on the first printed circuit board PCB 1. Referring to fig. 3, the absorption circuit may be disposed in a gap between the first and second heat sinks S and near the first end of the first heat sink S. In the example of fig. 3, the snubber circuit may be arranged in the area shown by hatching. In the example of fig. 4, the snubber circuit may be arranged, for example, at a position aligned parallel to the power device cells Q5 and Q6 perpendicular to the paper surface.

In some embodiments of the present disclosure, the three-level converter system may further include a driving circuit. The driving circuit is configured to drive power devices in the multiphase three-level ANPC converter circuit to operate. The driving circuit is arranged on a second surface of the first printed circuit board PCB1 opposite to the first surface. In the example of fig. 4, in the third direction D3, the power device units Q1, … …, Q6 are located above the first printed circuit board PCB1 and the driving circuit is located below the first printed circuit board PCB 1.

In summary, the three-level converter system according to the embodiments of the present disclosure is capable of efficiently and reasonably dissipating heat and realizing a compact physical structure.

As used herein and in the appended claims, the singular forms of words include the plural and vice versa, unless the context clearly dictates otherwise. Thus, when referring to the singular, the plural of the corresponding term is generally included. Similarly, the terms "comprising" and "including" are to be construed as being inclusive rather than exclusive. Likewise, the terms "comprising" and "or" should be interpreted as inclusive, unless such an interpretation is expressly prohibited herein. Where the term "example" is used herein, particularly when it follows a set of terms, the "example" is merely exemplary and illustrative and should not be considered exclusive or broad.

Further aspects and scope of applicability will become apparent from the description provided herein. It should be understood that various aspects of the present application may be implemented alone or in combination with one or more other aspects. It should also be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

While several embodiments of the present disclosure have been described in detail, it will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present disclosure without departing from the spirit and scope of the disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A three-level converter system, comprising:

a first printed circuit board;

a plurality of heat sinks arranged perpendicular to a first surface of the first printed circuit board, wherein each heat sink extends along a first direction, the plurality of heat sinks are arranged in parallel along a second direction, each two adjacent heat sinks form a heat sink pair, the second direction is perpendicular to the first direction, and a plane formed by the first direction and the second direction is parallel to the first surface of the first printed circuit board; and

a multiphase three level active neutral point clamped converter circuit, wherein each phase leg of the multiphase three level active neutral point clamped converter circuit comprises at least two single phase three level active neutral point clamped converter circuits, each single phase three level active neutral point clamped converter circuit comprising an upper leg and a lower leg, power devices in the upper leg being disposed in close proximity to a first side of a first heat sink of the heat sink pair and in parallel along the first direction on the first printed circuit board, and power devices in the lower leg being disposed in close proximity to a second side of a second heat sink of the heat sink pair and in parallel along the first direction on the first printed circuit board, the first side being disposed opposite the second side.

2. The three level converter system of claim 1, wherein each phase leg of the multi-phase three level active neutral point clamped converter circuit further comprises at least two first inductors, an output of each single phase three level active neutral point clamped converter circuit coupled to a first end of one first inductor, second ends of the at least two first inductors coupled to each other, the first inductors disposed on an extension of the first heat sink in the first direction and proximate to the first end of the first heat sink.

3. The three-level converter system of claim 2, further comprising: a second printed circuit board on which a filter circuit is arranged, the filter circuit being configured to filter a current output from the first inductor;

wherein the first inductor is arranged between the first printed circuit board and the second printed circuit board or the first inductor is arranged below the second printed circuit board.

4. A three-level converter system according to claim 3, characterized in that the three-level converter system further comprises: a main control board arranged perpendicular to the first surface of the first printed circuit board, the main control board being arranged at a first edge of the first printed circuit board, the main control board being for controlling an output current and an output voltage of the multiphase three level active neutral point clamped converter circuit and for controlling an operating state of the three level converter system.

5. The three level converter system of claim 2, wherein the multiphase three level active neutral point clamped converter circuit further comprises: at least one first dc bus capacitor and at least one second dc bus capacitor disposed on the first printed circuit board, the first dc bus capacitor coupled between a positive voltage potential end and a neutral voltage potential end, the second dc bus capacitor coupled between a negative voltage potential end and the neutral voltage potential end.

6. The three level converter system of claim 5, wherein a capacitor of the first dc bus capacitor and the second dc bus capacitor having a large capacitance value is disposed on an extension of the first heat sink in the first direction and near a second end of the first heat sink.

7. The three level converter system of claim 6, wherein a capacitor of the first and second dc bus capacitors having a small capacitance value is disposed in a gap between the first and second heat sinks and proximate the second end of the first heat sink.

8. The three-level converter system of claim 6 or 7, further comprising a cooling air input port arranged such that externally input cooling air flows in the first direction from the second end of the first heat sink to the first end of the first heat sink.

9. The three-level converter system of any one of claims 2-7, further comprising an snubber circuit disposed on the first printed circuit board, the snubber circuit comprising a capacitor bank and a resistor bank in series with each other, the capacitor bank comprising a plurality of capacitors in series-parallel with each other, the resistor bank comprising a plurality of resistors in series-parallel with each other, the snubber circuit coupled between a midpoint of the upper leg and a midpoint of the lower leg, the snubber circuit configured to suppress overvoltage from the power device in the multi-phase three-level active neutral point clamped converter circuit, the snubber circuit disposed in a gap between the first heat sink and the second heat sink and proximate the first end of the first heat sink.

10. The three-level converter system of any one of claims 1-7, further comprising a drive circuit disposed on a second surface of the first printed circuit board opposite the first surface, the drive circuit configured to drive power devices in the multiphase three-level active neutral point clamped converter circuit to operate.