FR3068545B1 - VOLTAGE CONVERTER, ELECTRICAL SYSTEM, MOTOR VEHICLE, AND MANUFACTURING METHOD THEREOF - Google Patents

Abstract

The voltage converter (104) includes first and second bus bars (106, 108), at least one power module (110) having at least one pair of first and second controllable switches (112, 114). There is provided a capacitor for each power module (110), this capacitor having a value of at least 500 micro Farad, preferably at least 560 micro Farad, and being located sufficiently close to the controllable switches (112, 114) so that the bus bars (106, 108, 122) define, for each pair of controllable switches (112, 114), a conduction path (408) starting from the first terminal of the capacitor, passing successively through each of these two switches controllable (112, 114) and terminating at the second capacitor terminal, this conduction path (408) having an inductance of at most 40 Henry nano, preferably at most 30 Henry nano.

Description

TITLE

VOLTAGE CONVERTER, ELECTRICAL SYSTEM, MOTOR VEHICLE, AND MANUFACTURING METHOD THEREOF

TECHNICAL AREA

The present invention relates to a voltage converter, as well as an electrical system, a motor vehicle and a manufacturing method thereof.

TECHNOLOGICAL BACKGROUND

It is known to use a voltage converter of the type comprising: - first and second bus bars, - at least one power module comprising: - at least one pair of first and second controllable switches, each controllable switch having two main terminals and a control terminal for selectively opening and closing the controllable switch between its two main terminals, the first main terminal of the first controllable switch being connected to the first bus bar and the second main terminal of the second controllable switch being connected to the second bus bar, - for each pair of controllable switches, a third busbar, the second main terminal of the first controllable switch and the first main terminal of the second controllable switch being connected to the third busbar, at least one capacitor having first andsecond terminals connected respectively to the first and second bus bars.

The first and second bus bars are designed to receive a high DC supply voltage. The capacitor or capacitors have the function of filtering this supply voltage. For the filtering to be effective, this or these capacitors have a high capacity, at least equal to 500 micro Farad and are placed in a capacitor block located near the ends of the first and second busbar where the supply voltage is applied. The object of the invention is to propose a voltage converter having improved filtering of the supply voltage.

SUMMARY OF THE INVENTION For this purpose, it is proposed a voltage converter of the aforementioned type, characterized in that there is provided a capacitor for each power module, this capacitor having a value of at least 500 micro Farad, of preferably at least 560 micro Farad, and being located sufficiently close to the controllable switches for the bus bars define, for each pair of controllable switches, a conduction path from the first terminal of the capacitor, passing successively by each of these two switches controllable and ending at the second terminal of the capacitor, this conduction path having an inductance of at most 40 nano Henry, preferably at most 30 nano Henry.

Thanks to the invention, a capacitor is placed as close as possible to the controllable switches of each power module, which makes it possible to improve the filtering. This solution is also more interesting than that which would have been to add, in addition to the capacitor block, small capacitors, for example ceramic capacitors, near the power modules. Indeed, the solution proposed by the invention makes it possible to obtain the same result while limiting the number of electronic components and therefore the cost and bulk of the voltage converter.

Optionally, each conduction path has a length of at most 100 mm, preferably at most 70 mm.

Also optionally, each of the controllable switches of each power module is located at a distance from an axis on which the capacitor is centered between 10 and 30 mm, preferably between 15 and 25 mm.

Optionally also, the voltage converter further comprises a heat sink housing having a horizontal periphery surrounding the power module or modules and the associated capacitors, the heat sink housing having, on this horizontal periphery, openings of an air inlet and, at a center, a downward air outlet opening, the at least one capacitor being located closer to a vertical axis passing through the air outlet opening, than the controllable switches .

Optionally also, the controllable switches of each pair are arranged to form a hash arm.

Also optionally, the voltage converter comprises three power modules each having two pairs of controllable switches.

It is also proposed an electrical system comprising: - a voltage converter according to the invention, - an electric motor having phases respectively associated with the power modules, each phase of the electric motor having two ends respectively connected to the two third bus bars of the module associated power.

Optionally, the electric motor is adapted to drive wheels of a motor vehicle.

It is also proposed a motor vehicle comprising an electrical system according to the invention. There is also provided a method for manufacturing a voltage converter according to the invention, comprising: for each power module, the determination of a position of the associated capacitor sufficiently close to the controllable switches for the busbars to define, for each pair of controllable switches, a conduction path from the first terminal of the capacitor, passing successively through each of these two controllable switches and ending at the second terminal of the capacitor having an inductance of at most 40 nano Henry, preferably of at most 30 nano Henry, - the manufacture of the voltage converter by placing, for each power module, the capacitor associated with the determined position.

DESCRIPTION OF THE FIGURES

Figure 1 is an electrical diagram of an electrical system comprising a voltage converter implementing the invention.

Figure 2 is a three-dimensional view of a power module and associated capacitor located in the voltage converter.

Figure 3 is a three-dimensional view of the capacitor alone.

Figure 4 is a three-dimensional view of the power module without the capacitor.

Figure 5 is a three-dimensional view of the voltage converter. Fig. 6 is a block diagram illustrating steps of a method of manufacturing the voltage converter.

DETAILED DESCRIPTION

With reference to FIG. 1, an electrical system 100 embodying the invention will now be described.

The electrical system 100 is for example intended to be implanted in a motor vehicle.

The electrical system 100 firstly comprises a power supply source 102 designed to deliver a DC voltage U, for example between 20 V and 100 V, for example 48 V. The power source 102 comprises for example a drums.

The electrical system 100 further comprises an electric machine 130 having a plurality of phases (not shown) for presenting respective phase voltages.

The electrical system 100 further comprises a voltage converter 104 connected between the power source 102 and the electrical machine 130 to convert between the DC voltage U and the phase voltages.

The voltage converter 104 firstly comprises a positive busbar 106 and a negative busbar 108 intended to be connected to the power source 102 to receive the DC voltage U, the positive busbar 106 receiving a high electrical potential. and the negative bus bar 108 receiving a low electrical potential.

The voltage converter 104 further comprises at least one power module 110 having one or more phase bus bars 122 for respectively being connected to one or more phases of the electrical machine 130, to provide their respective phase voltages.

In the example described, the voltage converter 104 comprises three power modules 110 each comprising two phase bus bars 122 connected to two phases of the electrical machine 130.

More specifically, in the example described, the electrical machine 130 comprises two three-phase systems each having three phases, and intended to be electrically out of phase by 120 ° relative to each other. Preferably, the first phase busbars 122 of the power modules 110 are respectively connected to the three phases of the first three-phase system, while the second phase busbars 122 of the power modules 110 are respectively connected to the three phases of the second three-phase system. .

Each power module 110 includes, for each phase bus 122, a high side switch 112 connected between the positive bus bar 106 and the phase bus 122 and a low side switch 114 connected between the phase bus 122. and the negative busbar 108. Thus, the switches 112, 114 are arranged to form a hash arm, wherein the phase busbar 122 forms a midpoint.

Each switch 112, 114 comprises first and second main terminals 116, 118 and a control terminal 120 for selectively opening and closing the switch 112, 114 between its two main terminals 116, 118 as a function of a control signal which it is applied to him. The switches 112, 114 are preferably transistors, for example metal-oxide-semiconductor ("Metal Oxide Semiconductor Field Effect Transistor") field-effect transistors having a gate forming the control terminal. 120, and a drain and a source respectively forming the main terminals 116,118.

In the example described, the switches 112, 114 each have the form of a plate, for example substantially rectangular, having an upper face and a lower face. The first main terminal 116 extends on the lower face, while the second main terminal 118 extends on the upper face. In addition, the lower face forms a heat dissipation face.

The voltage converter 104 further comprises, for each power module 110, a capacitor 124 having a positive terminal 126 and a negative terminal 128 respectively connected to the positive bus bar 106 and the negative bus bar 108.

It will be appreciated that the positive bus bar 106, the negative bus bar 108 and the bus bars 122 are rigid elements designed to withstand electrical currents of at least 1 A. They preferably have a thickness of at least 1 mm.

In addition, in the example described, the electric machine 130 has both an alternator and an electric motor function. More specifically, the motor vehicle further comprises a heat engine (not shown) having an output axis to which the electric machine 130 is connected by a belt (not shown). The heat engine is intended to drive wheels of the motor vehicle through its output axis. Thus, in operation as an alternator, the electric machine provides electrical energy towards the power source 102 from the rotation of the output axis. The voltage converter 104 then operates as a rectifier. In operation as an electric motor, the electric machine drives the output shaft (in addition to or in place of the engine). The voltage converter 104 then functions as an inverter.

The electric machine 130 is for example located in a gearbox or in a clutch of the motor vehicle or instead of the alternator.

In the following description, the structure and arrangement of the elements of the voltage converter 104 will be described in more detail, with reference to a vertical direction H-B, "H" representing the top and "B" representing the bottom.

With reference to FIG. 2, in the example described, the busbars 106, 108, 122 respectively comprise planar portions 202, 204, 206 that are horizontal and coplanar, and that extend side by side.

Furthermore, each controllable switch 112, 114 is in the form of a substantially rectangular plate and its first main terminal 116 extends over at least part of a lower face (not visible in the figures), while its second main terminal 118 extends on an upper face.

For each pair of controllable switches 112, 114, the rear face of the first switch 112 is pressed against one of the planar portion 202 of the first bus bar 106 and the flat portion 206 of the third bus bar 122, so as to connect its first main terminal 116 to the first busbar 106 or to the third busbar 122. In the example described, the rear face of the first controllable switch 112 is pressed against the planar portion 202 of the first busbar 106. , the upper face of the first switch 112 is connected via at least one conductive tab 208 to the other of the planar portion 202 of the first bus bar 106 and the flat portion 206 of the third bus bar 122, so as to connect its second main terminal 116 to the first bus bar 106 or to the third bus bar 122. In the example described, the upper face of the first switch 112 is connected via three tabs 208 the flat portion 206 of the third bus bar 122.

Furthermore, for each pair of controllable switches 112, 114, the rear face of the second controllable switch 114 is pressed against one of the flat portion 204 of the second bus bar 108 and the flat portion 206 of the third bus bar 122 so as to connect its first main terminal 116 to the second bus bar 108 or to the third bus bar 122. In the example described, the rear face of the second switch 114 is pressed against the flat portion 206 of the third bus bar 122 In addition, the upper face of the second switch 114 is connected via at least one tab 210 to the other of the plane portion 204 of the second bus bar 108 and the flat portion 206 of the third bus bar 122, so as to connect its second main terminal 118 to the second bus bar 108 or the third bus bar 122. In the example described, the upper face of the second bus Uptor 114 is connected via at least one conductive tab 210 to the planar portion 204 of the second bus bar 108.

Thus, because of the arrangement of the busbars 106, 108, 122 which extend next to each other instead of being stacked, it is possible to limit the vertical bulk of the power module 110.

Furthermore, the control terminals 120 of the controllable switches 112, 114 extend in the example described on their upper face and are connected to control pins 212.

With reference to FIG. 3, each capacitor 124 has a value of at least 500 Farad micro, preferably at least 560 Farad micro. Each capacitor 124 is for example a chemical capacitor.

Capacitors 124 are large. For example, the largest dimension of each capacitor 124 is at least 15 mm. Generally, this larger dimension is at least 30 mm. For example, each capacitor 124 is generally cylindrical in shape with a radius of between 5 and 15 mm and a height of between 18 mm and 40 mm, preferably between 20 mm and 35 mm.

Furthermore, each capacitor 124 has, on a lower circular face, a central pin forming its first terminal 126 and two lugs forming its second terminal 128.

With reference to FIG. 4, for each power module 110, the associated capacitor 124 is intended to be centered on an axis 402. Furthermore, the first busbar 106 has a perforation 404 intended to receive the pin forming the first terminal 126 of the capacitor 124 and the second busbar 108 has two perforations 406 for respectively receiving the two lugs forming its second terminal 128.

The busbars 106, 108, 122 define, for each pair of controllable switches 112, 114, a conduction path 408 starting from the first terminal 126 of the capacitor 124 (shown in FIG. 4, through the perforation 404), passing successively through each one. of these two controllable switches 112, 114 and terminating at the second terminal of the capacitor 124 (shown in Figure 4, by one of the perforations 406). In FIG. 4, only the conduction path 408 of one of the two pairs of controllable switches 112, 114 is shown. Another similar conduction path of course also exists for the other pair of controllable switches 112, 114. The axis 402, and therefore the capacitor 124, is located sufficiently close to the controllable switches 112, 114 for each conduction path 408 to have an inductance of at most 40 nano hen, preferably at most 30 nano hen. To obtain such a small inductance, the conduction path 408 preferably has a length of at most 100 mm, more preferably at most 70 mm. In addition, always to obtain such a small inductance, each controllable switch 112, 114 is preferably located at a distance of between 10 and 30 mm from the axis 402, more preferably between 15 and 25 mm. Thus, the controllable switches 112, 114 are both, on the one hand, sufficiently far from the axis 402 to allow the capacitor 124 to be installed and, on the other hand, close enough so that each induction path 408 can be short enough to present the desired inductance. In the example described, the controllable switches 112, 114 are located at the four corners of a trapezium having a small base (distance between the two high-side switches 112) and a large base (distance between the two low-side switches). . The axis 402 is located less than 10 mm from the middle of the large base. Thus, the switches 112, 114 surround the capacitor 124, which allows them to be placed near the capacitor 124.

With reference to FIG. 5, the voltage converter 104 furthermore comprises a heat dissipating box 502 comprising a horizontal periphery surrounding the power modules 110 and the capacitors 124. This horizontal periphery is provided with fins 504 delimiting between them openings. In addition, the heat dissipating casing 502 has, in one center, an air outlet opening 508 downwards, this air being for cooling the electric machine 130.

The capacitors 124 are preferably positioned closer to the air outlet opening 508 than the power modules 110, and in particular the controllable switches 112, 114. Thus, the capacitors 124 are located in the center and the power 110 at the periphery of the voltage converter 104.

In the example described, the voltage converter 104 is mounted on the electric motor 130, the latter having a rotor (not shown) forming a fan sucking the air through the air outlet opening 508, so as to establish air flows extending from the air inlet openings 506 to the air outlet opening 508 and cooling the power modules 110, and in particular the controllable switches 112, 114.

Due to their arrangement in the center of the voltage converter 104, the capacitors 124 do not prevent these air flows from passing through the power modules 110, whereas they are placed respectively closer to the power modules 110.

With reference to FIG. 6, a method of manufacturing the voltage converter 104 will now be described.

For each power module 110, during a step 602, a position of the capacitor 124 associated sufficiently close to the controllable switches 112, 114 is determined so that the busbars 106, 108, 122 define, for each pair of controllable switches 112, 114, a conduction path 408 starting from the first terminal 126 of the capacitor 124, passing successively through each of these two controllable switches 112, 114 and terminating at the second terminal 128 of the capacitor 124 having an inductance of at most 40 nano Henry, preferably at most 30 Henry nano. This determination can for example be carried out by means of a computer simulation.

During a step 604, the voltage converter 104 is manufactured by placing, for each power module 110, the capacitor 124 associated with the determined position that was determined in step 602.

The present invention is not limited to the embodiment described above, but is instead defined by the following claims. It will indeed be apparent to those skilled in the art that modifications can be made thereto.

Moreover, the terms used in the claims should not be understood as limited to the elements of the embodiment described above, but should instead be understood as covering all the equivalent elements that a person skilled in the art can deduce from his knowledge. General.

Claims (10)

A voltage converter (104) comprising: - first and second bus bars (106, 108), - at least one power module (110) comprising: - at least one pair of first and second controllable switches (112, 114), each controllable switch (112, 114) having two main terminals (116, 118) and a control terminal (120) for selectively opening and closing the controllable switch (112, 114) between its two main terminals (116, 118) the first main terminal (116) of the first controllable switch (112) being connected to the first bus bar (106) and the second main terminal (118) of the second controllable switch (114) being connected to the second bus bar (108). for each pair of controllable switches (112, 114), a third bus bar (122), the second main terminal (118) of the first controllable switch (112) and the first main terminal (116) of the second interrupte 90, 128) connected to the third bus bar (122), at least one capacitor (124) having first and second terminals (126, 128) respectively connected to the first and second bus bars (106, 108), characterized in that there is provided a capacitor (124) for each power module (110), this capacitor (124) having a value of at least 500 micro Farad, preferably at least 560 micro Farad, and being located sufficiently close to controllable switches (112, 114) for the bus bars (106, 108, 122) to define, for each pair of controllable switches (112, 114), a conduction path (408) from the first terminal (126) of the capacitor (124) passing successively through each of these two controllable switches (112, 114) and terminating at the second terminal (128) of the capacitor (124), this conduction path (408) having an inductance of at most 40 nano Henry , preferably nce of not more than 30 nano Henry. The voltage converter (104) according to claim 1, wherein each conduction path (408) has a length of at most 100 mm, preferably at most 70 mm. The voltage converter (104) according to claim 1 or 2, wherein each of the controllable switches (112, 114) of each power module (110) is located at a distance from an axis (402) on which the capacitor (124) is centered between 10 and 30 mm, preferably between 15 and 25 mm. The voltage converter (104) according to any of claims 1 to 3, further comprising a heat sink package (502) having a horizontal periphery surrounding the power module (s) (110) and the at least one capacitor ( 124) associated, the heat dissipating housing (502) having, on this horizontal periphery, air inlet openings (506) and, at a center, an air outlet opening (508) towards the bottom, the capacitor or capacitors (124) being located closer to a vertical axis (510) passing through the air outlet opening (508) than the controllable switches (112, 114). The voltage converter (104) according to any one of claims 1 to 4, wherein the controllable switches (112, 114) of each pair are arranged to form a hash arm. The voltage converter (104) according to any one of claims 1 to 5, comprising three power modules (110) each having two pairs of controllable switches (112, 114). 7. Electrical system (100) comprising: - a voltage converter (104) according to any one of claims 1 to 6, - an electric motor (130) having phases respectively associated with the power modules (110), each phase an electric motor (130) having two ends respectively connected to the two third bus bars (122) of the associated power module (110). The electrical system (100) of claim 7, wherein the electric motor (130) is adapted to drive wheels of a motor vehicle. 9. Motor vehicle comprising an electrical system (100) according to claim 7 or 8. The method (600) for manufacturing a voltage converter (104) according to any one of claims 1 to 6, comprising: - for each power module (110), determining (602) a position of the a capacitor (124) associated sufficiently close to the controllable switches (112, 114) for the busbars (106, 108, 122) to define, for each pair of controllable switches (112, 114), a conduction path (408) departing the first terminal (126) of the capacitor (124), passing successively through each of these two controllable switches (112, 114) and terminating at the second terminal (128) of the capacitor (124) having an inductance of at most 40 nano Henry preferably, at most Henry nano, - the manufacture (604) of the voltage converter (104) by placing, for each power module (110), the capacitor (124) associated with the determined position.