Patent Description:
At present, an electronic energy conversion device usually includes multiple power units that have a same topology and that are connected in parallel to each other for performing power conversion. The multiple power units, each of which is individually packaged, are connected in parallel with each other, to form the electronic energy conversion device, so as to save costs and facilitate maintenance of the electronic energy conversion device.

Under a certain power, it is more cost-effective to form the power module in the electronic energy conversion device by a larger number of parallel-connected low-power power units as compared with a smaller number of parallel-connected high-power power units. In addition, the low-power power units are technically mature, and can be packaged in a wide variety of methods.

However, an inverter having a three-level topology is not suitable for the small-sized (for example, <NUM>) low-power power unit package structure, resulting in a higher overall cost of the inverter.

<CIT> discloses an inverter system, so that currents respectively flowing through inverter modules are substantially equal. The inverter system includes multiple inverter modules connected in parallel. Input terminals of all the inverter modules are connected to a same DC input bus, and output terminals of all the inverter modules are connected to the same AC output bus. An input contact S1 of the DC input bus and an output contact S2 of the AC output bus are designed so that an impedance difference between any two branches between S <NUM> and S2 does not exceed a preset value.

<CIT> discloses a power semiconductor module. First and second element pairs formed by connecting FWDs and MOSFETs in antiparallel are connected in series and sealed by resin to configure a core module. In the core module, a first drain electrode, a first source electrode, a second drain electrode, and a second source electrode are exposed to the surface. A cover with terminals is put on the core module. At this time, each of the direct-current positive electrode terminal, the direct-current negative electrode terminal, and the alternating-current terminal of the cover with terminals is electrically connected to each of the first drain electrode, the second source electrode, and the first source electrode and the second drain electrode.

<CIT> discloses a power module comprising two elements, and a three-level power conversion device using same. A first electrode M1 that is connected to a higher-side potential portion of a first element pair <NUM>, a second electrode M2 that is connected to a connection portion between a lower-side potential portion of the first element pair <NUM> and a higher-side potential portion of a second element pair <NUM>, and a third electrode M3 that is connected to a lower-side potential portion of the second element pair <NUM>, are provided on one of the main-surface sides of a module casing. The first electrode M1 and the third electrode M3 are arrayed in a direction orthogonal to a longitudinal direction of the module casing on one of the end sides in the longitudinal direction. The second electrode M2 is arranged on the other end side in the longitudinal direction of the module casing. Three dual-element triple-terminal power modules with the same configuration, configured as described above, are used to configure a three-level power converter of one phase.

The invention is defined by independent apparatus claim <NUM>. Preferred embodiments are described by the dependent claims.

For clearer illustration of the technical solutions according to embodiments of the present disclosure or conventional techniques, hereinafter are briefly described the drawings to be applied in embodiments of the present disclosure or conventional techniques. Apparently, the drawings in the following descriptions are only some embodiments of the present disclosure, and other drawings may be obtained by those skilled in the art based on the provided drawings without creative efforts.

The technical solutions in the embodiments of the present disclosure will be described clearly and completely hereinafter in conjunction with the drawings in the embodiments of the present disclosure. Apparently, the described embodiments are only some rather than all of the embodiments of the present disclosure. Any other embodiments obtained based on the embodiments of the present disclosure by those skilled in the art without any creative effort fall within the scope of protection of the present disclosure.

In the present disclosure, the term "include", "comprise" or any variant thereof is intended to encompass nonexclusive inclusion so that a process, method, article or device including a series of elements includes not only those elements but also other elements which have not been listed definitely or an element(s) inherent to the process, method, article or device. Moreover, the expression "comprising a(n). " in which an element is defined will not preclude presence of an additional identical element(s) in a process, method, article or device comprising the defined element(s) unless further defined.

A conventional inverter is produced at a high cost. In order to reduce the cost of the inverter, a power unit <NUM> applied to an inverter is provided according to an embodiment of the present disclosure. The structure of the power unit <NUM> is shown in the dashed box in <FIG>. The power unit <NUM> includes: a first package module <NUM>, a second package module <NUM> and a third package module <NUM>. Each of the first package module <NUM>, the second package module <NUM> and the third package module <NUM> is provided with two switch transistors that are complementary to each other.

In an embodiment, in a case that the power unit <NUM> is arranged in an inverter, two input terminals of the first package module <NUM> are respectively connected to a positive electrode and a neutral point of the inverter on a DC side of the inverter. Two input terminals of the second package module <NUM> are respectively connected to a negative electrode and the neutral point of the inverter on the DC side of the inverter. An output terminal of the first package module <NUM> and an output terminal of the second package module <NUM> are respectively connected to two input terminals of the third package module <NUM>. An output terminal of the third package module <NUM> is connected to an AC side of the inverter. The first package module <NUM>, the second package module <NUM> and the third package module <NUM> form the power unit <NUM> having a three-level topology, thereby improving the efficiency and quality of the inverter.

The output terminal of the first package module <NUM> and the output terminal of the second package module <NUM> may be respectively connected to the two input terminals of the third package module <NUM> through copper bars or cables.

It should be noted that, when the inverter operates under a large current, package modules in each power unit generates heat at different times, thus the heat generated by each power unit is in a safe range, so as to prevent the inverter from being damaged by great heat. Therefore, by connecting the three package modules in the aforementioned manner, the power unit <NUM> including the three package modules and having the three-level topology ensures that the inverter is capable of operating under a large current.

In the power unit <NUM>, the first package module <NUM> and the second package module <NUM> are arranged in one half of an inner space of the power module <NUM>, and the third package module <NUM> is arranged in the other half of the inner space of the power module <NUM>.

In an embodiment, the power unit <NUM>, when packaged, has a rectangular shape, and the inner space of the power unit <NUM> may be divided into two halves by a middle line perpendicular to a longer side of the power unit <NUM>, as shown by the dot dash line in <FIG>, where the third package module <NUM> being arranged in a lower half is shown as an example, and the third package module <NUM> may alternatively be arranged in an upper half in practice. Alternatively, the inner space of the power unit <NUM> may be divided into two halves by a middle line perpendicular to a shorter side of the power unit <NUM>, as shown by the dot dash line in <FIG>, where the third package module <NUM> being arranged in a right half is shown as an example, and the third package module <NUM> may alternatively be arranged in a left half in practice. The manner in which the inner space is divided and in which the package modules are arranged is not limited in the present disclosure, and may be set according to actual conditions.

It should be noted that, since each package module in the packaged power unit <NUM> also has a rectangular shape, a longer side of each package module is required to be parallel to the longer side of the power unit <NUM> when the inner space of the power unit <NUM> is divided in any one of the two above manners.

In a preferred embodiment, the three package modules in the power unit <NUM> have a Y-shaped arrangement. However, the arrangement of the three package modules in the power unit <NUM> includes but is not limited to the aforementioned arrangement. The first package module <NUM>, the second package module <NUM>, and the third package module <NUM> may have another arrangement, such as an inverted Y-shape, a horizontal Y-shape or may be arranged in sequence, which may be selected according to actual conditions and is not limited in the present disclosure, all of which falls within the scope of the present disclosure.

In a case that the inner space of the power unit <NUM> is divided by the middle line perpendicular to the longer side of the power unit <NUM>, as shown in <FIG>, the three package modules in the power unit <NUM> having the Y-shaped arrangement indicates that the third package module <NUM> is arranged in the lower half of the inner space of the power unit <NUM>, with a symmetry axis of the third package module <NUM> that is parallel to the longer side of the package module <NUM> being in the middle of the lower half, that is, the third package module <NUM> is located in the middle of the lower half; and the first package module <NUM> and the second package module <NUM> are arranged in the upper half of the inner space of the power unit <NUM> and are symmetrical to each other with respect to the symmetry axis of the third package module <NUM>.

In a case that the inner space of the power unit <NUM> is divided by the middle line perpendicular to the shorter side of the power unit <NUM>, as shown in <FIG>, the three package modules in the power unit <NUM> having the Y-shaped arrangement indicates that the third package module <NUM> is arranged in the right half of the inner space of the power unit <NUM>, with a symmetry axis of the third package module <NUM> that is perpendicular to the longer side of the package module <NUM> being in the middle of the right half, that is, the third package module <NUM> is located in the middle of the right half of the inner space of the power unit <NUM>; and the first package module <NUM> and the second package module <NUM> are arranged in the left half of the inner space of the power unit <NUM> and are symmetrical to each other with respect to the symmetry axis of the third package module <NUM>.

In the power unit <NUM>, a control terminal of the first package module <NUM> and a control terminal of the second package module <NUM> are located on a first side of the power unit <NUM> that is away from the half of the inner space for arranging the third package module <NUM>, and a control terminal of the third package module <NUM> is located on a second side of the power unit <NUM> that is away from the half of the inner space for arranging the first package module <NUM> and the second package module <NUM>, thereby facilitating connection with an driver board inside the inverter.

In a case that the inner space of the power unit <NUM> is divided in the manner shown in <FIG>, the first package module <NUM> and the second package module <NUM> are arranged in the upper half of the inner space of the power unit <NUM>, the control terminals of the first package module <NUM> and the second package module <NUM> are located on the upper side of the power unit <NUM>. Referring to the upper left part of <FIG>, the upper side of the power unit <NUM> is the first side of the power unit <NUM>. The third package module <NUM> is arranged in the lower half of the inner space of the power unit <NUM>, and the control terminal of the third package module <NUM> is located on the lower side of the power unit <NUM>, referring to the lower left part of <FIG>, the lower side of the power unit <NUM> is the second side of the power unit <NUM>.

Similarly, in a case that the inner space of the power unit <NUM> is divided in the manner shown in <FIG>, the first package module <NUM> and the second package module <NUM> are arranged in the left half of the inner space of the power unit <NUM>, the control terminals of the first package module <NUM> and the second package module <NUM> are located on the left side of the power unit <NUM>, and the left side of the power unit <NUM> is the first side of the power unit <NUM>. The third package module <NUM> is arranged in the right half of the inner space of the power unit <NUM>, and the control terminal of the third package module <NUM> is located on the right side of the power unit <NUM>, and the right side of the power unit <NUM> is the second side of the power unit <NUM>.

In a case that the three package modules are arranged in the aforementioned manners, a small-sized package structure may be adopted for the power unit <NUM>, for example, a <NUM> series IGBT module as shown in <FIG> may be adopted, thereby reducing the cost of the power unit.

It can be seen from the above that, each of the first package module <NUM>, the second package module <NUM> and the third package module <NUM> includes two switch transistors that are complementary to each other. The first package module <NUM> and the second package module <NUM> are arranged in one half of the inner space of the power unit <NUM>, and the third package module <NUM> is arranged in the other half of the inner space of the power unit <NUM>. The control terminal of each of the package modules is arranged on a side of the half for arranging the package module that is away from the other half. Thus, the power unit can adopt a small-sized packaging structure, such as a <NUM> series IGBT module, without changing a layout of driver boards, thereby reducing the cost of the power unit <NUM> and the inverter. In addition, driver boards for the power unit <NUM> according to the embodiment may have a simple layout. Moreover, since the two input terminals of the first package module <NUM> and the two input terminals of the second package module <NUM> are on the same side, a structure design of a DC input bus <NUM> is facilitated. In other words, the DC input bus <NUM> can have a simple structure.

Referring to <FIG>, a power module <NUM> applied to an inverter is provided according to an embodiment of the present disclosure. The power module <NUM> includes at least two power units <NUM> according to the aforementioned embodiment of the present disclosure. A power module including four power units <NUM> is shown in <FIG> as an example.

In the power module <NUM>, DC sides of all of the at least two power units <NUM> are connected with each other in parallel, and AC sides of all of the at least two power units <NUM> are connected with each other in parallel. The DC side of the power unit <NUM> refers to the input terminals of the first package module and the input terminals of the second package module described in the aforementioned embodiment. The AC side of the power unit <NUM> refers to the output terminal of the third package module described in the aforementioned embodiment.

It should be noted that, the power module <NUM> formed by the multiple power units <NUM> that are connected with each other in parallel may have a small parasitic inductance and a high power level, resulting in an inverter having a high power level. Further, the driver boards and the DC input bus <NUM> can have simple layout and configuration.

In a preferred embodiment, the power module <NUM> includes four power units <NUM> according to the aforementioned embodiment of the present disclosure.

In applications, if the power module <NUM> includes a large number of power units <NUM>, currents through the power units <NUM> are different since the actual accuracy in the packaging process of each power unit <NUM> is different from the ideal accuracy. As a result, some power units <NUM> may bear higher currents, and are more easily damaged.

In order to solve the above problem, two circulation buses are provided in the power module <NUM>, that is, a first circulation bus <NUM> and a second circulation bus <NUM> as shown in <FIG>. In an embodiment, output terminals of first package modules <NUM> in all power units <NUM> are connected with each other through the first circulation bus <NUM>, and output terminals of second package modules <NUM> in all power units <NUM> are connected with each other through the second circulation bus <NUM>.

Due to the first circulation bus <NUM> and the second circulation bus <NUM>, the output terminals of the first package modules <NUM> in all power unit <NUM> have a same potential, and the output terminals of the second package modules <NUM> in all power units <NUM> have a same potential. That is, potentials of the output terminals of the first package modules <NUM> in all power units <NUM> are made equal to each other, and potentials of the output terminals of the second package modules <NUM> in all power units <NUM> are made equal to each other, thereby avoiding the unequal currents that cause overload of some power units <NUM>, so as to prevent the power units from being damaged.

Referring to <FIG>, an inverter is provided according to an embodiment of the present disclosure. The inverter includes: a DC input bus <NUM>, an AC bus bar <NUM>, an AC output copper bar <NUM>, and the power module <NUM> according to the aforementioned embodiment of the present disclosure.

In the power module <NUM>, terminals serving as DC sides of all of the at least two power units <NUM>, that is, the input terminals of the first package modules <NUM> and the input terminals of the second package modules <NUM> are connected to respective electrodes of the DC input bus <NUM>.

The DC input bus <NUM> includes a DC input positive bus P+, a DC input neutral bus N, and a DC input negative bus P-. In the power module <NUM>, positive input terminals of the first package modules <NUM> in all power units <NUM> are connected to the DC input positive bus P+. Negative input terminals of the first package modules <NUM> in all power units <NUM> are connected to the DC input neutral bus N. Positive input terminals of the second package modules <NUM> in all power units <NUM> are connected to the DC input neutral bus N. Negative input terminals of the second package modules <NUM> in all power units <NUM> are connected to the DC input negative bus P-.

The inverter adopts the power module <NUM> according to the aforementioned embodiments, such that the DC input bus <NUM> of the inverter can have a simple configuration.

In the power module <NUM>, terminals serving as AC sides of all power units <NUM>, that is, output terminals of the third package modules <NUM>, are connected to the AC output copper bar <NUM> through the AC bus bar <NUM>.

A structure of the AC bus bar <NUM> will be described hereinafter by taking the power module <NUM> including four power units <NUM> as an example. As shown in <FIG>, the AC bus bar <NUM> includes a first parallel copper bar <NUM>, a second parallel copper bar <NUM> and a parallel confluence copper bar <NUM>.

Two ends of the first parallel copper bar <NUM> are respectively connected to terminals serving as AC sides of two power units <NUM> on a left side of the power module, and two ends of the second parallel copper bar <NUM> are connected to terminals serving as AC sides of another two power units <NUM> on a right side of the power module respectively. A left end of the parallel confluence copper bar <NUM> is connected to a middle point of the first parallel copper bar <NUM>, and a right end of the parallel confluence copper bar <NUM> is connected to a left end of the second parallel copper bar <NUM>. The left end of the parallel confluence copper bar <NUM> is connected to the AC output copper bar <NUM>. A DC input point is arranged at an upper right corner of the power module <NUM>.

In applications, the AC bus bar <NUM> may include at least one parallel copper bar and one parallel confluence copper bar <NUM>. Alternatively, the AC bus bar <NUM> may include only the parallel confluence copper bar <NUM>. The number of the parallel copper bars, and whether the parallel copper bar is included are not limited in the present disclosure and may be selected according to actual conditions.

In a case that the AC bus bar <NUM> has one level, the AC bus bar <NUM> includes only the parallel confluence copper bar <NUM>, and the parallel confluence copper bar <NUM> is connected to terminals serving as the AC sides of all power units <NUM>.

In a case that the AC bus bar <NUM> has two levels, the AC bus bar <NUM> includes at least one parallel copper bar and one parallel confluence copper bar <NUM>. The at least one parallel copper bar forms the first level, and each of the at least one parallel copper bar is connected to terminals serving as AC sides of at least two corresponding power units <NUM>. In this case, there may be one or more power units <NUM> that are not connected to the parallel copper bar, or all power units <NUM> may be connected to corresponding parallel copper bars, which depends on actual conditions and is not limited herein, all of which falls within the protection scope of the present disclosure. The parallel confluence copper bar <NUM> forms the second level. The parallel confluence copper bar <NUM> may be connected to all power units via all parallel copper bars, or the parallel confluence copper bar <NUM> may be connected to all parallel copper bars and terminals serving as the AC sides of the one or more power units <NUM> that are not connected to the parallel copper bar, which depends on actual conditions and is not limited herein, all of which falls within the protection scope of the present disclosure.

In a case that the AC bus bar <NUM> has multiple levels, the AC bus bar <NUM> includes at least two parallel copper bars and one parallel confluence copper bar <NUM>. All parallel copper bars are divided into multiple levels. A lowest-level parallel copper bar is connected to terminals serving as AC sides of at least two corresponding power units <NUM>. In this case, there may be one or more power units <NUM> that are not connected to the parallel copper bar, or all power units <NUM> may be connected to corresponding parallel copper bars, which depends on actual conditions and is not limited herein, all of which falls within the protection scope of the present disclosure. Except for the lowest-level parallel copper bar, a higher-level parallel copper bar may be connected to a parallel copper bar that has a level lower than the higher-level parallel copper bar and is not connected to a parallel copper bar having a level higher than the higher-level parallel copper bar. That is, the higher-level parallel copper bar may be connected to only at least two parallel copper bars that have a level lower than the higher-level parallel copper bar and are not connected to a parallel copper bar having a level higher than the higher-level parallel copper bar, or the higher-level parallel copper bar may be connected to the parallel copper bar that has a level lower than the higher-level parallel copper bar and is not connected to a parallel copper bar having a level higher than the higher-level parallel copper bar, and terminals serving as AC sides of a part or all of the one or more power units <NUM> that are not connected to a parallel copper bar, which may be determined according to actual conditions and is not limited herein, all of which falls within the protection scope of the present disclosure. A last-level of the AC bus bar is the parallel confluence copper bar <NUM>. The parallel confluence copper bar <NUM> may be connected to all highest-level parallel copper bars, or may be connected to all highest-level parallel copper bars and terminals serving as AC sides of all power units <NUM> that are not connected to a parallel copper bar, which depends on actual conditions and is not limited herein, all of which falls within the protection scope of the present disclosure.

In the aforementioned two implementations of the AC bus bar <NUM>, each lowest-level parallel copper bar may be connected to a terminal serving as the AC side of the power unit through a connection point at any position on the lowest-level parallel copper bar. A parallel copper bar other than the lowest-level parallel copper bar may be connected to a next-level parallel copper bar through a connection point at any position of the parallel copper bar. The parallel confluence copper bar <NUM> may be connected to the highest-level parallel copper bar through a connection point at any position of the parallel confluence copper bar <NUM>. The parallel confluence copper bar <NUM> may be connected to the AC output copper bar <NUM> through a connection point any position of the parallel confluence copper bar <NUM>. The arrangement of the connection point is not limited to the above implementation, and may be selected according to actual conditions, all of which falls within the protection scope of the present disclosure.

It is to be noted that, the present disclosure is not limited to using copper bars to implement the parallel connection of the AC sides of power modules <NUM>, and buses may alternatively be used to implement the parallel connection of the AC sides of power modules, which may be selected according to actual situations, all of which falls within the protection scope of the present disclosure.

In the power module <NUM>, the power units <NUM> may be connected in parallel with each other by using any of the aforementioned connection manners, as long as it is ensured that paths passing through the power units <NUM> between the DC input bus <NUM> and the AC bus bar <NUM> have a same impedance, that is, paths between the DC input point DCin and an AC output point ACout have a same impedance, such that currents through the power units are the same, thereby reducing the difference between the currents and achieving the same current through the power units.

Hereinafter, the power module <NUM> including four power units <NUM> is taken as an example to illustrate the impedance between the DC input bus <NUM> and the AC bus <NUM> in detail.

As shown in <FIG>, it is assumed that the DC side of the rightmost power unit <NUM> is closest to the DC input point DCin, and the AC side of the leftmost power unit <NUM> is closest to the AC output point ACout. Further, equivalent impedances between DC sides of a power unit <NUM> and a power unit <NUM>, a power unit <NUM> and a power unit <NUM>, a power unit <NUM> and a power unit <NUM> are defined as a first impedance R1, a second impedance R2, and a third impedance R3 respectively. Equivalent impedances between AC sides of the power unit <NUM> and the power unit <NUM>, the power unit <NUM> and the power unit <NUM>, the power unit <NUM> and the power unit <NUM> are defined as a fourth impedance R4, a fifth impedance R5, and a sixth impedance R6 respectively.

In this case, there are four paths from the DC input point DCin to the AC output point ACout, which are described in the following.

A first path is from the DC input point DCin, through the power unit <NUM>, the sixth impedance R6, the fifth impedance R5, the fourth impedance R4, and to the AC output point ACout.

A second path is from the DC input point DCin, through the third impedance R3, the power unit <NUM>, the fifth impedance R5, the fourth impedance R4, and to the AC output point Acout.

A third path is from the DC input point DCin, through the third impedance R3, the second impedance R2, the power unit <NUM>, the fourth impedance R4, and to the AC output point Acout.

A fourth path is from the DC input point DCin, through the third impedance R3, the second impedance R2, the first impedance R1, the power unit <NUM>, and to the AC output point Acout.

In order to ensure that the same current flows through the four paths, it is required that a sum of the impedances R4, R5, and R6, a sum of the impedances R3, R4, and R5, a sum of the impedances R2, R3, and R4, and a sum of the impedances R1, R2, and R3 are equal to each other. That is, R4+R5+R6=R3+R4+R5=R2+R3+R4=R1+R2+R3, or a difference between any two of the above four sums is within an error range.

By arranging the parallel confluence copper bar <NUM> and the parallel copper bars in the aforementioned manner, the DC input point DCin of the DC input bus <NUM> and the AC output point ACout of the AC output copper bar <NUM> are respectively arranged at positions that are symmetrical to each other with respect to a central point of the power module <NUM>, such as diagonal positions, such that the DC input point Dcin is away from the AC output point ACout as far as possible, thereby ensuring that the DC input bus <NUM> and the AC bus <NUM> have the same impedance in paths passing through all power units.

The DC input point DCin of the DC input bus <NUM> and the AC output point ACout of the AC output copper bar <NUM> may be respectively located at two corners of the power module <NUM> that are opposite to each other in a diagonal direction. For example, referring to <FIG>, the parallel confluence copper bar <NUM> is connected to the first parallel copper bar <NUM> and the second parallel copper bar <NUM>, such that the AC output point ACout is arranged at the lower left corner, and the DC input point DCin is arranged at the upper right corner. Of course, the positions of the AC output point ACout of the AC output copper bar <NUM> and the DC input point DCin of the DC input bus <NUM> may also be asymmetrical, as long as they are away from each other as far as possible and paths passing through all power units have the same impedance.

In applications, the power units may be connected in other manners, as long as it is ensured that the paths passing through all of the power units between the DC input bus <NUM> and the AC bus <NUM> have the same impedance, which is not described in detail herein.

In applications, the inverter further includes: a controller, a first driver board and a second driver board. One side of the first driver board is connected to control terminals on the first side of each of the at least two power units; one side of the second driver board is connected to the control terminal on the second side of each of the at least two power units; and another side of the first driver board and another side of the second driver board are connected to the controller.

The above configuration does not affects an original layout of driver boards in the inverter, and the power units share the two driver boards, thereby facilitating layout design of the driver boards. In applications, each power unit may be connected to a separate driver board.

As shown in <FIG>, an inverter is provided according to an embodiment of the present application, based on the aforementioned embodiment, the inverter further includes a radiator.

In the inverter, the at least two power units <NUM> in the power module <NUM> are sequentially arranged on the radiator.

In applications, the first package module <NUM> and the second package module <NUM> in each of the power units <NUM> are arranged at a cold air end of the radiator, and the third package module <NUM> in each of the power units <NUM> is arranged at a hot air end of the radiator. That is, the area where the package modules are densely arranged in each power unit <NUM> is arranged at the cold air end of the radiator, and the area where the package modules are sparsely arranged in each power unit <NUM> is arranged at the hot air end of the radiator. Thus, the heat dissipation speed of the area where the package modules are densely arranged in each power unit <NUM> is improved, and every part of each power unit <NUM> is properly dissipated, such that the temperature distribution on the radiator is more even, and heat accumulation in some areas is avoided. Each power unit <NUM> can make full use of the heat dissipation capacity of the radiator, thereby improving the heat dissipation efficiency of the inverter.

In an optional embodiment, in a case that the radiator adopts an air duct with an air inlet at an upper end and an air outlet at a lower end as shown in <FIG>, the upper end of the air duct is the cold air end, and the lower end of the air duct is the hot air end. In a case that the radiator adopts an air duct with the air outlet at the upper end and the air inlet at the lower end as shown in <FIG>, the upper end of the air duct is the hot air end, and the lower end of the air duct is the cold air end. In a case that the radiator adopts an air duct with the air inlet at a left end and the air outlet at a right end as shown in <FIG>, the left end of the air duct is the cold air end, and the right end of the air duct is the hot air end. In a case that the radiator adopts an air duct with the air outlet at the left end and the air inlet at the right end as shown in <FIG>, the left end of the air duct is the hot air end, and the right end of the air duct is the cold air end. The configuration of the air duct is not limited in the present disclosure, may be selected according to actual situations, all of which falls within the protection scope of the present disclosure.

As shown in <FIG>, <FIG> and <FIG>, an inverter is provided according to an embodiment of the present application, based on the aforementioned embodiment, the inverter further includes at least one first heat pipe <NUM>, and/or, at least one second heat pipe <NUM>.

The number of the first heat pipe <NUM> and the second heat pipe <NUM> is not limited herein, and may be determined according to actual conditions.

In a case that the inverter includes the first heat pipe <NUM>, each first heat pipe <NUM> passes across two or more of the at least two power units <NUM>, and is arranged on a same cross section of halves of inner spaces for arranging the third package module of the power units, such as the cross-section A shown in <FIG>, to transfer heat from high temperature places to low temperature places.

For example, as shown in <FIG> and <FIG>, the inverter includes two first heat pipes <NUM>. The two first heat pipes <NUM> pass across four power units <NUM>, and are arranged close to bottoms of the third package modules <NUM>. The two first heat pipes <NUM> are arranged side by side with a certain distance apart, to give full play to their heat dissipation capacity.

For example, as shown in <FIG> and <FIG>, the inverter includes two first heat pipes <NUM>. One of the first heat pipes <NUM> passes across two adjacent power units <NUM>, and is arranged close to bottoms of the third package modules <NUM>. The other one of the first heat pipes <NUM> passes across another two adjacent power units <NUM>, and is arranged close to bottoms of the third package modules <NUM>.

It should be noted that, the aforementioned two arrangements of the first heat pipe <NUM> are merely illustrative, and the arrangement of the first heat pipe <NUM> includes but is not limited to the aforementioned two arrangements.

In a case that the inverter includes the second heat pipe <NUM>, each second heat pipe <NUM> passes across two or more of the at least two power units <NUM>, and is arranged on a same cross section of halves of the inner space of the power units where the first package module <NUM> and the second package module <NUM> are arranged, such as the cross-section area B shown in <FIG>, to transfer heat from high temperature places to low temperature places.

For example, as shown in <FIG> and <FIG>, the inverter includes two second heat pipes <NUM>. The two second heat pipes <NUM> pass across four power units <NUM>, and are arranged close to bottoms of the first package modules <NUM> and second package modules <NUM>. The two second heat pipes <NUM> are arranged side by side with a certain distance apart, to give full play to their heat dissipation capacity.

For example, as shown in <FIG> and <FIG>, the inverter includes two second heat pipes <NUM>. One of the second heat pipes <NUM> passes across two adjacent power units <NUM>, and is arranged close to bottoms of the first package modules <NUM> and the second package modules <NUM>. The other one of the second heat pipes <NUM> passes across another two adjacent power units <NUM>, and is arranged close to bottoms of the first package modules <NUM> and the second package modules <NUM>.

It should be noted that, the aforementioned two arrangements of the second heat pipe <NUM> are merely illustrative, and the arrangement of the second heat pipe <NUM> includes but is not limited to the aforementioned two arrangements.

Due to the first heat pipe <NUM> and/or the second heat pipe <NUM>, the heat may be transferred from places with a high temperature to places with a low temperature. The temperature at a same cross section (such as the cross section A and the cross section B) may be maintained to be the same to the greatest extent, that is, different power units <NUM> have the same temperature at the same cross section, thereby realizing overall uniform temperature of the power module <NUM>.

The embodiments in this specification are described in a progressive manner. For the same or similar parts between the embodiments, one may refer to the description of other embodiments. Each embodiment lays emphasis on differences from other embodiments. Since the system embodiment is similar to the method embodiment, the description for the system embodiment is relatively simple. For related parts, reference may be made to description in the method embodiment. The system embodiment described above are merely illustrative, and units described as separate components may or may not be physically separated. The components shown as units may be or not be physical units, i.e., the units may be located at the same place or may be distributed onto multiple network units. All or a part of the modules may be selected based on actual needs to realize the objective of the solutions according to the embodiments. The solutions according to the embodiments can be understood and implemented by those skilled in the art without creative work.

The person skilled in the art can further appreciate that the elements and algorithm steps of each embodiment described in connection with the embodiments disclosed herein can be implemented in electronic hardware, computer software or a combination of both, in order to clearly illustrate the interchangeability of the hardware and software, the composition and steps of the various examples have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. The person skilled in the art can use different methods for implementing the described functions for each particular application; such implementation should not be considered to be beyond the scope of the present disclosure.

Claim 1:
An active neutral point clamped, ANPC, three-level inverter comprising a power unit (<NUM>), wherein the power unit comprises: a first package module (<NUM>), a second package module (<NUM>), and a third package module (<NUM>), wherein:
each of the first package module (<NUM>), the second package module (<NUM>) and the third package module (<NUM>) is provided with two switch transistors that are complementary to each other;
the first package module (<NUM>) and the second package module (<NUM>) are arranged in a first half of an inner space of the power unit (<NUM>), and the third package module (<NUM>) is arranged in a second half of the inner space of the power unit (<NUM>);
characterized in that
a control terminal of the first package module (<NUM>) and a control terminal of the second package module (<NUM>) are arranged on a first side of the power unit (<NUM>) that is away from the second half of the inner space for arranging the third package module (<NUM>), and a control terminal of the third package module (<NUM>) is arranged on a second side of the power unit (<NUM>) that is away from the first half of the inner space for arranging the first package module (<NUM>) and second package module (<NUM>).