TWI819920B - Power module with dispersed staggered conductive parts and low parasitic inductance - Google Patents

Abstract

A power module with dispersed staggered conductive elements and low parasitic inductance includes at least a base, a first unit and a second unit. The base is provided with at least one current input bus and at least one current output bus. The first and second units respectively include a circuit base provided with a plurality of power components, each power component having a parallel current input terminal and a parallel current output terminal connected to the respective circuit base. The first and second units are respectively connected in series with each other through a plurality of series-connected conductive elements, and are respectively connected in series to the current input bus and the current output bus through a plurality of input and output conductive elements. The series conductive elements, the input conductive elements and the output conductive elements overlap in projection in the length direction, are staggered and dispersed in the projection in the width direction, and/or overlap in projection in the height direction.

Description

Power module with dispersed staggered conductive parts and low parasitic inductance

The invention relates to a power module, in particular to a power module with dispersed staggered conductive parts and low parasitic inductance.

Third-generation semiconductors are currently a popular high-tech field and play a pivotal role in the development of 5G, electric vehicles, and renewable energy. The so-called third-generation semiconductor, also known as "wide bandgap semiconductor", generally refers to silicon carbide (SiC) or gallium nitride (GaN). Its energy gap is about three times that of traditional semiconductors silicon (Si) and gallium arsenide (GaAs). times, it can be used in high-frequency, high-temperature, high-current and high-voltage operating environments, and overall has excellent performance and stability.

Among the many application fields of third-generation semiconductors, the demand for electric vehicles is undoubtedly the main driving force for power semiconductor components. The core technology of electric vehicles lies in "battery, motor and electronic control". Here is a brief explanation: First of all, the three-phase motor is the heart of the electric vehicle. It generates a rotating magnetic field (RMF, Rotating Magnetic Field) to drive the rotor in the motor, and then drives the electric vehicle. axle; in order to generate a rotating magnetic field, the three-phase motor needs to use alternating current with a phase difference as power; however, the battery pack such as lithium battery equipped with the electric vehicle is a direct current power supply, which means that a direct current and a DC current are required between the battery and the motor. Conversion of alternating current; this conversion is achieved by the inverter, the brain of the electric vehicle.

The function of the inverter is not only to convert the input current into an AC signal, but also to control the three-phase motor through technologies such as Pulse Width Modulation (PWM). Essentially, an inverter is a power module that contains the above-mentioned power semiconductors and realizes electronic control of the motor through circuit design. For example, the faster the rotation speed of the rotating magnetic field, the faster the rotor in the motor. The rotation speed of the rotating magnetic field is determined by the frequency of the AC signal. In other words, electric vehicles can directly change the frequency of the input current by controlling the frequency of the input current. Motor speed provides a more reliable, linear control method compared to traditional internal combustion engine mechanisms. In addition, the input current of the motor also directly affects the strength of the generated magnetic field. For electric vehicles with high power output, power modules that can handle large currents are inevitably needed.

In AC circuits, current flowing through wires or components will produce a time-varying magnetic field according to Ampere's law. According to Faraday's law of induction and Cold's law, the time-varying magnetic field will produce a countervailing induced electromotive force, which affects the current signal. The above effect is similar to that of inductance, so it is generally called "parasitic inductance" or "miscellaneous inductance". This unintended parasitic inductance is undesirable in practice because it blocks the rapid transformation of current signals. Usually, this effect can be ignored when the frequency is not high. However, under high-frequency and high-current operating conditions, the influence of noise becomes more serious, which may cause the phase delay or lead of the signal, distort the overall signal, and affect the transmission and Conversion efficiency and reduced stability will significantly affect the efficiency of the motor in converting electrical energy into mechanical energy.

US Patent No. 10405450 discloses the problems caused by parasitic inductance in high-power modules, such as voltage overshoot (Voltage shooting), ringing (Ringing) and other phenomena. In addition, for power modules installed in parallel, it also includes Temperature unevenness caused by current imbalance. All the above factors will cause circuit system instability, reduce conversion efficiency, and even limit the maximum switching frequency. Therefore, as shown in Figure 1, this case proposes to reduce the circuit length, increase the conductor cross-sectional area, generate a destructive magnetic field, and reduce the height of the module to bring the power module closer to the endpoint. Among them, the current flows along the current direction 8 through After passing through the two power components 7, a recirculation area 9 is formed at the output bus, which can reduce the locally generated parasitic inductance. However, this layout method can only be connected to the local area in the center due to the output bus located in the upper center of the figure. The circuit below is close to each other, but the part on the right side of the figure must avoid the wiring area and must keep a distance, which limits its ability to reduce parasitic inductance. As shown in Figure 2, US Patent No. 8637964 also attempts to disclose a power module with low stray inductance. By placing the return current as close as possible to the original current path in the circuit design, the current direction 8 is also in the power module. A return flow path is formed in the module. However, under large current and high-frequency transformation, this horizontal double-loop layout will cause uneven current flow due to the different distances traveled by the inner and outer rings of each loop, and the distance between the outer rings will be Far away, the effect of mutual cancellation of noise is limited.

Parasitic inductance has a huge impact on the performance of high-frequency circuits. In order to overcome this problem, the present invention discloses a power module that can effectively and significantly reduce the parasitic inductance of the overall power module through a special circuit conductor layout that is shunted in parallel and dispersed and interleaved.

One object of the present invention is to provide a power module with low parasitic inductance, which can significantly reduce the parasitic inductance generated by connecting large current signals in parallel and using a conductor structure that is dispersed and interlaced with each other.

Another object of the present invention is to provide a power module with low parasitic inductance, in which the source bus bar and the drain bus bar are arranged on the side to facilitate circuit derivation.

Another object of the present invention is to provide a power module with low parasitic inductance, which makes the circuit structure design of the low parasitic inductance power module more selective and flexible through the staggered and dispersed configuration of the horizontal and vertical directions.

According to the above-mentioned case, a power module with dispersed staggered conductive elements and low parasitic inductance is disclosed, including: at least one base extending along a length direction, and having two opposite side edges in the length direction, corresponding to the two opposite sides. At least one current input bus and at least one current output bus insulated from each other are provided at one of the side edges; a first unit includes a first circuit arranged on the base along a width direction perpendicular to the length direction The base part, the first circuit base part is provided with a plurality of first power elements, each of the first power elements has a first current input end connected in parallel with each other and a first current output end connected in parallel with each other; wherein the first current input end terminal or one of the above-mentioned first current output terminals is conductively mounted to the above-mentioned first circuit base; and

A second unit including a second circuit base arranged on the base along the width direction perpendicular to the length direction, and the second circuit base is spaced apart from the first circuit base in the length direction, and the second circuit base is A plurality of second power components are provided on the circuit base, and each of the above-mentioned second power components has a second current input terminal connected in parallel with each other and a second current output terminal connected in parallel with each other; wherein the above-mentioned second current input terminal or the above-mentioned second One of the current output terminals is conductively installed to the above-mentioned second circuit base; wherein, the above-mentioned first unit and the above-mentioned second unit respectively have one end along the above-mentioned length direction and are connected in series with each other through a plurality of series-connected conductive members that are dispersedly arranged with each other. , and the far ends of the first unit and the second unit opposite to the one end connected in series are respectively connected in series to the above-mentioned current input bus through a plurality of mutually dispersed input conductive elements and a plurality of mutually dispersed output conductive elements. rows and the above-mentioned current output busbars, and when the above-mentioned series conductive elements, the above-mentioned input conductive elements and the above-mentioned output conductive elements correspond to the positions in the above-mentioned length direction, the projections constituting a plane in the above-mentioned length direction and width direction are staggered and dispersedly arranged with each other, and the above-mentioned Projections of a plane formed by a length direction and a height direction perpendicular to the above-mentioned length direction and the above-mentioned width direction intersect with each other; thereby, the above-mentioned dispersed series conductive elements, the above-mentioned dispersed input conductive elements, and the above-mentioned The dispersed output conductive parts will form individual inductances that cancel each other when the current passes through, so that the overall parasitic inductance is reduced.

Through the low parasitic inductance power module disclosed in this case, the large current signal input to the module is shared by power semiconductors such as SiC and GaN connected in parallel. Each of the power semiconductors is equipped with a plurality of wires distributed in the above-mentioned width direction. Provides large currents to the connection for dispersed and stable input and output; the induced magnetic fields generated by a wire will cancel each other within a short range. The wires are dispersed and staggered to and from the design, effectively reducing the parasitic inductance effect generated by high-frequency currents; especially whether Staggering in the width direction or height direction, or even staggering in the width and height directions at the same time, can flexibly meet the height or width restrictions of users with different structural needs, creating a product with excellent high-frequency response and electrical performance. The high-power module can effectively reduce the adverse effects of parasitic inductance; and the source busbar and drain busbar are configured on the side to facilitate circuit export and meet usage needs, solving the above problems in one fell swoop.

1, 1’, 1”: power module

2. 2’: base

20, 20’, 20”: Current input bus

22, 22’, 22”: current output bus

3:Unit 2

30, 30’, 30”: Second circuit base

32: Second power component

34: Second current input terminal

36: Second current output terminal

4:Unit 1

40, 40’, 40”: first circuit base

42:First power component

44: First current input terminal

46: First current output terminal

5: Elevated board

50, 50’, 50”: series conductive parts

52, 52’, 52”: output conductive parts

54, 54’: Input conductive parts

60: Magnetic field integral path

7: Power components

8: Current direction

9:Reflow area

X: length direction

Y: width direction

Z: Height direction

Figure 1 is a schematic diagram of a conventional technology.

Figure 2 is a schematic diagram of another conventional technology.

Figure 3 is a schematic top view of the first preferred embodiment of the present invention, illustrating how the input conductive elements, the output conductive elements and the series conductive elements are dispersed and staggered in the length and width planar projection directions.

FIG. 4 is a schematic side view of the embodiment of FIG. 3 , illustrating how to bring the wires closer in the height direction and cancel the noise during the round trip process of the circuit.

FIG. 5 is a schematic projection diagram of the current path of the embodiment of FIG. 3 , illustrating the principle of parasitic inductance cancellation.

Figure 6 is a schematic top view of the second preferred embodiment of this case.

FIG. 7 is a schematic side view of the embodiment of FIG. 6 .

Figure 8 is a schematic top view of the third preferred embodiment of this case.

The relevant technical contents, features and functions of this case will be clearly presented in the following detailed description of the preferred embodiments with reference to the drawings. The same components in each embodiment are marked with similar numbers.

The first preferred embodiment of the low parasitic inductance power module 1 of this case, as shown in Figures 3 to 5, includes a base 2 provided with a current input bus 20 and a current output bus 22 to provide an overall large current. Signal (tens to hundreds of amps) input module. For the convenience of explanation, the up and down direction in Figure 3 is defined as a length direction X, the width direction in the figure is defined as Y, and the direction perpendicular to the paper surface is the height direction Z. The base 2 in this example uses a ceramic substrate made of dielectric material, whereby a heat dissipation device (not shown) can be disposed below the power component.

In this example, the second unit 3 is connected to the current input bus 20 , and the first unit 4 includes a first circuit base 40 extending along the width direction Y, and is provided with, for example, five first power elements 42 . 42 is exemplified here as a power transistor made of SiC. Of course, in other embodiments, other power transistors can also be selected according to application requirements, and the number can also be adjusted, so the example in this case should not be a limiting condition. The first circuit base 40 in this example is exemplified as a direct-clad copper (DBC) circuit board insulated and mounted on the base 2. When the input current enters from the current input bus 20, it will pass through a plurality of input conductive elements connected in parallel. 54 is input to the first power component 42. For the convenience of explanation, it is defined that the bottom of the first power component 42 is welded and connected to the first circuit base 40 and is connected to The electrode of the input conductive member 54 is the first current input terminal 44 . The input current flows through the first power element 42 and proceeds along the X direction as shown in the figure, and then reaches the top electrode of the first power element 42 as the first current output terminal 46 to be connected to the series conductive member 50 . In this example, the input conductive members 54 are twenty wires connected in parallel and dispersedly welded through a section of the elevated plate 5 in the middle to lead to each first current input terminal 44. Therefore, large input currents of tens to hundreds of amperes can be input. Share it evenly to effectively alleviate the current heating effect of each conductive part. Especially in this embodiment, an aluminum wire is used as an example to bear a large amount of current.

In the first unit 4 of this example, each first power element 42 is controlled synchronously by a first gate signal. When the gate signal acts, the source and drain of each power transistor are connected, and the input current signal is connected to the series conductive member 50 through a plurality of first current output terminals 46 connected in parallel with each other. Conducted to the second current input terminal 34 of the second power element 32 on the second circuit base 30 . It is worth noting that the current signal enters and exits the first unit 4 mainly through the input conductive member 54, which in this example is a total of 20 wires parallel to each other along the length direction X. For the convenience of explanation, this part The loop with the current direction in the -X direction is called the "current input half" and covers the range from the current input bus 20 to the first power element 42 .

For ease of explanation, each first power element 42 is used as a boundary here. As shown in Figures 3 and 4, the current flows from each first current output terminal 46 to the second circuit base 30 through 20 series-connected conductive members 50, and The stage in which the current is allowed to pass from the second current input terminal 34 through each of the second power components 32 and the second current output terminal 36 and finally conduct from the output conductive member 52 to the current output bus 22 is called "current output half process". A plurality of second power components 32 connected in parallel are synchronously controlled by an AC signal of a second gate signal to drive conduction between the source and drain of each power transistor.

If the three-dimensional coordinates of each circuit or wire are gradually defined in the length direction Looking down at the projection of the X-Y plane, during the current input half-way, the 20 aluminum strips input to the conductive parts 54 are arranged in a manner of two on each outermost part and four in each middle part; while during the current output half-way, the conductive parts 50 are connected in series. The aluminum strips and the output conductive member 52 are each in a group of four strips. During the current input half process and the current output half process, the lines between the input conductive members 54 and the series conductive members 50 adjacent to each other are staggered and scattered, and the lines between the input conductive members 54 and the output conductive members 52 are staggered. Distributed arrangement. From the projection of the side view on the X-Z plane formed from the length direction There will be crossovers between the lines.

Based on the present invention almost completely traveling through the same path along the length direction In the above example, the sum of the current closed loops including four circuits is zero, achieving the effect that the local parasitic inductances cancel each other. It is worth noting that although this case adopts a staggered and dispersed method of input and output in groups of two or four, the number of wires in each conductive component should not be a limitation. In this example, although the conductive element does not completely extend along the length direction The full and even distribution of the overall current, while maintaining a very close reciprocating circuit structure in three-dimensional space, allows the overall power module's stray inductance to be reduced to less than 5nH, or even less than 2nH. Compared with the long-distance loop design disclosed in the previous technology in Figures 1 and 2, the module disclosed in this case not only has a more uniform current distribution, but also has a much smaller integral zeroing path according to Ampere's law analysis. In other words, even though the above-mentioned previous proposal proposed a theoretical concept for reducing stray inductances, the round-trip current distribution area is too large, which not only causes uneven currents, but also makes the calculated cross-sectional area for cancellation of stray inductances very wide. wide, the actual effect of eliminating the induced magnetic field cancellation in each local small area is limited. In comparison, the decentralized and staggered design in this case has a very excellent effect in eliminating parasitic inductance.

Even though the first circuit base 40 and the second circuit base 30 of the above embodiment are two independent circuit boards as an example, the circuit configuration of this case is not limited to the above solution. The power module 1 of the second preferred embodiment of the present invention 'As shown in Figures 6 and 7, the same parts as those in the first preferred embodiment, such as the current input bus 20' and the current output bus 22', will not be described further. In this embodiment, the input conductive member 54' and the output conductive member 52' may be metal clip bonding/copper clip bonding (Clip Bond) sheets (for example, copper sheets), but are not limited thereto. The main difference between this embodiment and the previous embodiment is that the base 2' of this embodiment is a substrate of a single dielectric layer, and the first circuit base 40' and the second circuit base 30' are both on this dielectric layer. The metal circuit layers that are insulated from each other allow the copper sheets to be closer to each other in terms of structural arrangement through lithography technology. This example is the same as the previous embodiment. When the input current path and the output current path correspond to the same coordinate position in the length direction The output conductive members 52' will also be arranged staggered and scattered with each other in the projection on the X-Y plane formed by the length direction X-width direction Y in Figure 6 based on the distinction between the current input half range and the current output half range; The projections on the X-Z plane formed by the direction X-height direction Z are interlaced. Of course, the conductive member in this example is not limited to a simple aluminum strip, but can be other conductive metal strips. Although the overall circuit is different from the first embodiment, it still has an excellent back-and-forth staggered path to minimize the parasitic inductance effect, and the current flows evenly and dispersedly, which is completely in line with the ideal design.

The power module 1" of the third preferred embodiment of the present invention is shown in Figure 8. The same parts as the first two preferred embodiments will not be described further. In this example, the first circuit base 40" and the second The circuit base 30" is a conductive copper layer insulated from each other; the input current is input from the current input bus 20", After passing through the first power element and the series-connected conductive member 50", it reaches the second power element; and then flows back to the current output bus 22" through the output conductive member 52".

The power module disclosed in the present invention uses circuits and power components connected in parallel to evenly share the input large current to ensure uniform distribution of the current flow process; and the circuits form paths inside the module that are dispersed, overlapping and corresponding to each other. Close to overlapping decentralized circuits, this decentralized and staggered conduction method clearly reduces the parasitic inductance effect. In this way, the parasitic inductance can be reduced to less than 5nH by using the module of the present invention. In particular, the source bus bar and the drain bus bar are arranged on the side to facilitate circuit derivation. As for the description of the above embodiments, they are only for the convenience of understanding and are not limiting. Any equivalent effects and other changes and modifications produced in accordance with the structure of the following claims in this case fall within the scope of the patent covered by this case.

1: Power module

2: base

20:Current input bus

22:Current output bus

3:Unit 2

30: Second circuit base

32: Second power component

34: Second current input terminal

36: Second current output terminal

4:Unit 1

40:First circuit base

42:First power component

44: First current input terminal

46: First current output terminal

5: Elevated board

50: Series connection of conductive parts

52: Output conductive parts

54:Input conductive parts

X: length direction

Y: width direction

Claims (5)

A power module with dispersed staggered conductive parts and low parasitic inductance, include: At least one base extends along a length direction and has two opposite side edges in the length direction. At least one current input bus and at least one current output bus insulated from each other are provided at one of the two opposite side edges. Row; A first unit, including a first circuit base disposed on the base along a width direction perpendicular to the length direction, a plurality of first power components disposed on the first circuit base, each of the first power components having A first current input terminal connected in parallel with each other and a first current output terminal connected in parallel with each other; wherein one of the above-mentioned first current input terminal or the above-mentioned first current output terminal is conductively mounted to the above-mentioned first circuit base; and A second unit including a second circuit base arranged on the base along the width direction perpendicular to the length direction, and the second circuit base is spaced apart from the first circuit base in the length direction, and the second circuit base is A plurality of second power components are provided on the circuit base, and each of the above-mentioned second power components has a second current input terminal connected in parallel with each other and a second current output terminal connected in parallel with each other; wherein the above-mentioned second current input terminal or the above-mentioned second One of the current output terminals is conductively mounted to the base of the second circuit; Wherein, the above-mentioned first unit and the above-mentioned second unit respectively have one end along the above-mentioned length direction. The distal ends of the first unit and the second unit opposite to the one end connected in series are respectively connected to each other through a plurality of input conductive members dispersedly arranged to each other and a plurality of mutually dispersed input conductive members. The dispersedly arranged output conductive members are respectively connected in series to the above-mentioned current input bus and the above-mentioned current output bus, and when the above-mentioned series-connected conductive members, the above-mentioned input conductive members and the above-mentioned output conductive members correspond to the positions in the above-mentioned length direction, in the above-mentioned length The projections of the plane formed by the direction and the width direction are interlaced and dispersed with each other, and the projections of the plane formed by the above-mentioned length direction and a height direction perpendicular to the above-mentioned length direction and the above-mentioned width direction are interleaved with each other; thereby, the above-mentioned scattered series-connected conductive elements, The above-mentioned dispersed input conductive elements and the above-mentioned dispersed output conductive elements will form individual inductances that cancel each other when current passes through, so that the overall parasitic inductance is reduced. The power module with dispersed staggered conductive elements and low parasitic inductance as claimed in claim 1, wherein the base is a dielectric layer, and the first circuit base and the second circuit base are two pieces formed on the dielectric. Metal circuit layers on electrical layers that are insulated from each other. The power module with dispersed staggered conductive elements and low parasitic inductance as described in claim 2, wherein when the series conductive elements, the input conductive elements and the output conductive elements are at corresponding positions in the length direction, the dispersed series conductive elements are Connect conductive parts, The above-mentioned dispersed input conductive elements and the above-mentioned dispersed output conductive elements are arranged in a staggered and dispersed manner with each other in projections forming a plane in the above-mentioned length direction and width direction. The power module with dispersed staggered conductive elements and low parasitic inductance as claimed in claim 1, wherein the base is an insulating base, and the first circuit base and the second circuit base are two pieces respectively disposed on the insulating base. Circuit board on the base. The power module with dispersed staggered conductive elements and low parasitic inductance as described in claim 4, wherein when the above-mentioned series conductive elements, the above-mentioned input conductive element and the above-mentioned output conductive element correspond to the positions in the above-mentioned length direction, the above-mentioned dispersed series conductive elements Projections of the connecting conductive members, the dispersed input conductive members, and the dispersed output conductive members forming planes in the length direction and the height direction are interlaced with each other.

Images