Patent Description:
Power converters require that the temperature of the components, especially semi-conductors, capacitors, and busbar, are kept under specified limits in order to achieve good reliability. In addition, parasitic inductance in the commutation path must be minimized in order to achieve the proper operation of the semi-conductors. <CIT> discloses a power converter assembly according to the preamble of claim <NUM>. <CIT> discloses another power converter assembly.

The conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for assemblies that provide increased reliability and stability, and reduced size, weight, complexity, and/or cost. The present disclosure may provide a solution for at least one of these remaining challenges.

According to a first aspect, there is provided a power converter assembly according to claim <NUM>.

The assembly can include a first capacitor on a first side of the heat sink and a second capacitor on the second side of the heat sink. The first and second busbar assemblies can each be connected to both the first capacitor and the second capacitor.

The assembly can include multiple phases, e.g. six phases, each phase can include one or more semi-conductor modules. For example, each phase can include two semi-conductor modules. A first set of semi-conductor modules can be on the first side of the heat sink and a second set of the semi-conductor modules can be on a second side of the heat sink. The assembly can include a first capacitor on a first side of the heat sink and a second capacitor on the second side of the heat sink. The first capacitor and the second capacitor can be electrically connected to both the first and second sets of semi-conductor modules. The first capacitor can be electrically connected to the first set of semi-conductor modules through the first busbar assembly. The second capacitor can be electrically connected to the second set of semi-conductor modules through the second busbar assembly.

The assembly can include a first AC connector electrically connected to the first set of semi-conductor modules and a second AC connector electrically connected to the second set of semi-conductor modules. The first set of semi-conductor modules can be electrically connected to the first busbar assembly. The second set of semi-conductor modules can be electrically connected to the second busbar assembly.

The DC positive layer of the first busbar assembly can be electrically connected to the DC positive layer of the second busbar assembly. The DC negative layer of the first busbar assembly can be electrically connected to the DC negative layer of the second busbar assembly. The DC neutral layer of the first busbar assembly can be electrically connected to the DC neutral layer of the second busbar assembly.

The assembly can include three first AC connectors on the first side of the heat sink and three second AC connectors on the second side of the heat sink. The first and second busbar assemblies can be electrically connected to one another through the heat sink with a set of bushings. The set of bushings can include five bushings. Four of the bushings are periphery bushings and can be electrically connected to DC positive layers and/or the DC negative layers of the first busbar assembly and the second busbar assembly. A fifth of the five bushings can be a central bushing electrically connected to the DC neutral layers of the first busbar assembly and the second busbar assembly. The first, second, third and fourth bushings can have equivalent cross-sectional areas. The fifth bushing can have a cross-sectional area equal to the cross-sectional areas of the first and second bushing combined. The periphery bushings are equidistant from a longitudinal axis defined by the central bushing.

In accordance with another aspect, a power converter assembly includes a plurality of sets of semi-conductor modules, a common heat sink mechanically connected to each semi-conductor module, a first busbar assembly on a first side of the common heat sink, and a second busbar assembly on a second side of the common heat sink opposite from the first side. The first and second busbar assemblies are electrically connected to one another.

The first and second busbar assemblies can be similar to those described above. The assembly can include a plurality of first capacitors on a first side of the common heat sink and a plurality of second capacitors on the second side of the common heat sink. The first and second busbar assemblies can each be connected to both the plurality of first capacitors and the plurality of second capacitors. Each set of semi-conductor modules in each phase can include a plurality of semi-conductor modules. A first set of semi-conductor modules can be on the first side of the common heat sink and a second set of the semi-conductor modules can be on a second side of the common heat sink. Each semi-conductor module can include two semi-conductor switches. The assembly can include a first AC connector electrically connected to the first set of semi-conductor modules and a second AC connector electrically connected to the second set of semi-conductor modules.

So that those skilled in the art to which the subject invention appertains will readily understand how to make and use the devices and methods of the subject invention without undue experimentation, preferred embodiments thereof will be described in detail herein below, by way of example only and with reference to certain figures, wherein:.

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject invention. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of a power converter assembly in accordance with the invention is shown in <FIG> and is designated generally by reference character <NUM>. Other embodiments of the power converter assembly in accordance with the disclosure are provided in <FIG>, as will be described. The methods and systems of the present disclosure provide a busbar geometry and overall power converter assembly that result in compact cooling for semi-conductors and capacitors, and symmetry, thereby achieving a low parasitic inductance in the commutation loop. The power converter assembly structure of the present disclosure is very suitable for aerospace power electronic applications; or all type of applications requiring lightweight, compact power converters.

As shown in <FIG>, a power converter assembly <NUM> includes multiple phases, e.g. phases A1, B1, C1, A2, B2, and C2. Each phase includes a set of one or more semi-conductor modules, e.g. two semi-conductor modules. At least one of the top phases, e.g. one of phases A1, B1, C1, includes a first set 103a of two top semi-conductor modules 102a. At least one of the bottom phases, e.g. one of phases A2, B2, C2, includes a second set 103b of two bottom semi-conductor modules 102b. The assembly <NUM> includes a heat sink <NUM> mechanically connected to each semi-conductor module 102a and 102b. Heat sink <NUM> is a common heat sink <NUM>, meaning that multiple phases (e.g. phases A1-C2) of the power converter electronics are part of a single assembly <NUM>. Because power converter assembly <NUM> utilizes both sides of heat sink <NUM>, the usage of available cooling is maximized, direct cooling of the busbars (described below) is enabled, and the capacitors, e.g. capacitors 108a and 108b, described below, are kept below temperature limits, thereby enabling increased life. The heat-sink <NUM> mechanically connects and refrigerates semi-conductor modules 102a and 102b and capacitors, e.g. capacitors 108a and 108b, described below.

As shown in <FIG>, the first set 103a of semi-conductor modules 102a is on the first side 105a of the heat sink <NUM> and a second set 103b of semi-conductor modules 102b is on a second side 105b of the heat sink <NUM>. Each of the semi-conductor modules 102a and/or 102b includes two semi-conductor switches <NUM>. Each switch <NUM> is shown with a single semi-conductor. However, it is contemplated that a given switch <NUM> can include multiple semiconductors. By having semi-conductor modules 102a and 102b on both sides of heat sink <NUM>, power converter assembly <NUM> has a highly compact design that allows achieving high power density by using the two sides of the heat sink <NUM>, e.g. a cold plate, to allocate for the heat generated in power semi-conductor switches <NUM>.

As shown in <FIG>, assembly <NUM> includes a first busbar assembly 106a on a first side 105a of the heat sink <NUM>, and a second busbar assembly 106b on a second side 105b of the heat sink <NUM> opposite from the first side 105a. This busbar arrangement provides a compact design. The first and second bus bar assemblies 106a and 106b are cooled by the heat sink <NUM> in such a way that the capacitors, described below, are kept within their required thermal boundaries. The first set 103a of semi-conductor modules 102a are electrically connected to the first busbar assembly 106a. The second set 103b of semi-conductor modules 102b are electrically connected to the second busbar assembly 106b. The first and second busbar assemblies 106a and 106b, respectively, are electrically connected to one another through the heat sink <NUM> by way of two sets of bushings <NUM> and <NUM>', which are described in more detail below. In this way, the busbar assemblies 106a and 106b connect the semi-conductor modules 102a and 102b on both sides of the heat sink <NUM>.

As shown in <FIG>, the assembly <NUM> includes a plurality of first capacitors 108a, e.g. positive capacitors, on a first side 105a of the heat sink <NUM> and a plurality of second capacitors 108b, e.g. negative capacitors, on the second side 105b of the heat sink <NUM>. The busbar assembly arrangement enables the integration of the capacitors 108a and 108b on busbar assemblies 106a and 106b, thereby reducing parasitic inductance and increasing the heat transmission out of the capacitors 108a and 108b. This capacitor distribution allows for even distribution of currents among commutating semi-conductor modules 102a and 102b, and for optimization of the total capacitance. Positive capacitors 108a and negative capacitors 108b all together form a DC link for power converter assembly <NUM> of a six-phase power converter. There could be different number of capacitors than phases, e.g. you could have a single positive capacitor 108a and a single negative capacitor 108b for all six phases A1-C2, or each phase could have a respective capacitor 108a or 108b, which is how it is depicted in <FIG>. Because the DC link is split between the two sides of the heat sink <NUM>, the semi-conductor modules 102a on the first side 105a must connect to the capacitors 108a and 108b on both sides of the heat-sink <NUM>. To connect to the capacitors 108a and 108b on the opposite side of the heat sink <NUM>, two sets of bushings <NUM> and <NUM>' are used, where each set <NUM> and <NUM>' has five bushings. The connection of the capacitors 108a and 108b across heat sink <NUM> allows reduction in the total amount of capacitance required for the complete converter assembly <NUM> because each half of the DC link, Cvdc/<NUM>+ (108a) and Cvdc/<NUM>- (108b), are shared by the two busbar assemblies 106a and 106b. Moreover, positioning capacitors 108a and 108b on opposing sides of the heat sink <NUM> achieves a compact design, high power density, and equal current sharing, but, in turn, it may increase the challenge in terms of achieving low parasitic inductance. DC busbar assemblies 106a and 106b connect the semi-conductor modules 102a and 102b to respective DC capacitors 108a and 108b (short time energy storage). In a given phase pair, e.g. A1 and A2, each busbar assembly 106a and 106b electrically connects to each of capacitors 108a and 108b.

As shown in <FIG>, first and second busbar assemblies 106a and 106b, respectively, each include a DC positive layer <NUM>, a DC negative layer <NUM> and a DC neutral layer <NUM>. In other words, the DC-link capacitors 108a and 108b are split in positive and negative sets. Assembly <NUM> includes at least a first capacitor 108a and at least a second capacitor 108b electrically connected to respective first and second sets of semi-conductor modules 102a and 102b. The first capacitor 108a is electrically connected to the first set 103a of semi-conductor modules 102a through the first busbar assembly 106a. The second capacitor 108b is electrically connected to the second set 103b of semi-conductor modules 102b through the second busbar assembly 106b. The assembly <NUM> results in a compact construction that allows high power density values, high electrical performance and enabling fast switching, wide band gap semi-conductors.

With reference now to <FIG>, the assembly <NUM> includes a first AC connector, e.g. an AC input/output 110a, electrically connected to the first set 103a of semi-conductor modules 102a and a second AC connector, e.g. an AC input/output 110b, electrically connected to the second set 103b of semi-conductor modules 102b. The first AC input/output 110a, its respective semi-conductor modules 102a, and capacitors 108a, make up a single phase, e.g. phase A1, and the second AC input/output 110b, its respective semi-conductor modules 102b, and capacitors 108b, make up a single phase, e.g. phase A2, of a six phase power converter assembly <NUM>. The six phases are schematically shown in <FIG>. For six phase assembly <NUM>, the assembly <NUM> includes three AC inputs/outputs 110a on the first side 105a of the heat sink <NUM> and three AC inputs/outputs 110b on the second side 105b of the heat sink <NUM>. Heat sink <NUM> is common for all phases, while busbar assembly 106a is common to top phases A1, B1 and C1, and busbar assembly 106b is common to bottom phases A2, B2, and C2.

In <FIG>, a circuit schematic showing the connection for two phases, A1 and A2, one phase located on the first side of the heat-sink and a second phase located on the second side of the heat-sink is provided. As shown in <FIG>, the DC positive layer <NUM> of the first busbar assembly 106a is electrically connected to the DC positive layer <NUM> of the second busbar assembly 106b. The DC negative layer <NUM> of the first busbar assembly 106a is electrically connected to the DC negative layer <NUM> of the second busbar assembly 106b. The DC neutral layer <NUM> of the first busbar assembly 106a is electrically connected to the DC neutral layer <NUM> of the second busbar assembly 106b. Because the DC-link is split in half, e.g. a positive capacitor 108a on one side of the heat sink <NUM> and negative capacitor 108b on the other side, the semi-conductor modules 102a on one side must connect to the capacitors 108a and 108b on both sides of the heat-sink <NUM>. To connect the semi-conductor modules 102a to the capacitors 108b on the opposite side of the heat sink <NUM>, two sets of bushings <NUM> and <NUM>' are placed connecting the busbar assemblies 106a and 106b. The first and second busbar assemblies 106a and 106b are electrically connected to one another through the heat sink <NUM> with each set of bushings <NUM> and <NUM>', thereby also electrically connecting semi-conductor modules 102a and 102b to both the positive and negative capacitors 108a and 108b, respectively.

Each set of bushings <NUM> and <NUM>' includes a set of five cylindrical bushings 120a-120e, and is used to connect either the positive or negative busbar layers <NUM> and <NUM>, respectively. In order to minimize the parasitic inductance in the commutation loop it is convenient that this, either positive or negative conduction path, is physically close to a neutral conduction path. Therefore, each set of bushings <NUM> and <NUM>' has the four peripheral cylindrical bushings 102a-d connecting either the positive or negative busbar layers <NUM> and <NUM>, respectively, across the heat sink, and a central cylindrical bushing 102e connecting the opposing DC neutral layers <NUM> to one another. For a positive set of bushings <NUM>, the cylindrical peripheral bushings 120a-d, are in electrical connection with DC positive busbar layers <NUM> of the first busbar assembly 106a and the second busbar assembly 106b, e.g. as shown in <FIG>. For a negative set of bushings <NUM>', the cylindrical peripheral bushings 120a-d are electrically connected to DC negative busbar layers <NUM> of the first busbar assembly 106a and the second busbar assembly 106b. Those skilled in the art will readily appreciate that the connection for negative set of bushings <NUM>' to negative busbar layers <NUM> would be depicted in a similar to the connection for the positive set of bushings <NUM> in <FIG>. For negative set of bushings <NUM>', the cross-sectional view of <FIG> would be mirrored about an axis perpendicular to the axis A of <FIG>. In both cases, the fifth central bushing 120e is in electrical connection with DC neutral layers <NUM> of the first busbar assembly 106a and the second busbar assembly 106b. For each set of bushings <NUM> and <NUM>', the first, second, third and fourth bushings 120a-120d have equivalent cross-sectional areas to one another, and the fifth bushing 120e has a cross-sectional area approximately equal to two-times the cross-sectional area of one of the bushings 120a-120d. The cross-sectional areas are the circular cross-sections taken in a plane perpendicular to the longitudinal axes of bushings 120a-d. For each set of bushings <NUM> and <NUM>', bushings 120a-120d are positioned equidistant from longitudinal axis A of bushing 120e, such that bushings 120a-120d are positioned along a circle that is concentric with bushing 120e. The arrangement of bushings 120a-120e result in low parasitic inductance in the various commutation loops for all possible paths.

Claim 1:
A power converter assembly (<NUM>), comprising:
a semi-conductor module (102a, 102b);
a heat sink (<NUM>) mechanically connected to the semi-conductor module;
a first busbar assembly (106a) on a first side (105a) of the heat sink; and
a second busbar assembly (106b) on a second side (105b) of the heat sink opposite from the first side, wherein the first and second busbar assemblies are electrically connected to one another; the assembly characterized in that:
the first busbar assembly includes a DC positive layer (<NUM>), a DC negative layer (<NUM>) and a DC neutral layer (<NUM>), and
the second busbar assembly includes a DC positive layer (<NUM>), a DC negative layer (<NUM>) and a DC neutral layer (<NUM>).