FR2590005A1 - System of power semiconductor components cooled by circulation of a liquid - Google Patents

Abstract

System of power semiconductor components cooled by circulation of a liquid. Each component comprises two faces applied respectively against two metal blocks 53, 63 each equipped 56 with two internal channels 57, 60 through which a cooling liquid flows. The system comprises hydraulic ducting 68, 71, 72, 73, 69 linking these channels, in such a way that the liquid firstly passes through all the blocks of a first face of the components, then those of the second face, then sets off again in the opposite direction to again pass through all the blocks of the second face and all the blocks of the first face. Application to reactive energy compensation in high voltage stations.

Description

System of power semiconductor components cooled by circulation of a liquid
The present invention relates to a system of power semiconductor components cooled by the circulation of a liquid.

 The power semiconductor components are in the form of cylindrical disks, the diameter of which can be of the order of 100 mm. They include silicon junctions which can be crossed in operation by currents of between 1000 and 2000 A means, the heat losses reaching 2 to 5 KW per unit.

The performance of these components is highly dependent on the junction temperature, which must not exceed 100 to 1250C under steady conditions.

 In an operating system, it is necessary to cool these components efficiently while consuming as little energy as possible.

 For this, it is known to apply strongly on the flat faces of these components metal blocks each comprising internal channels through which a coolant flows.

 The blocks are hydraulically connected to each other using pipes, the connection being able to be made in series or in parallel.

 Connection in series is simple to implement and inexpensive because the number of pipes is relatively small. On the other hand, the liquid heats up with each passage through a block, so that the components operate at increasingly higher temperatures from the inlet to the outlet of the coolant. The parallel connection is more complex because of the large number of taps, but the temperature is uniform for the different components.

 Different types of hydraulic connection have been proposed to achieve a compromise between equalizing the temperatures of the various components and the cost of the installation. In one of these types of connection, known as counter-current, the components provided with their blocks being arranged in any order, the coolant successively passes through one of the blocks of the different components in one direction, then is returned in the opposite direction to through these same blocks, then crosses the other block of these components in the initial direction to be returned in the opposite direction through these same blocks. We can see that the temperature of the junction of the different components is established, during the operation of the system, at an average value which varies very little from one component to another. However, there appears a significant difference in average temperature between the two blocks applied to the two flat faces of the same component.

 This temperature difference causes an asymmetric heat exchange and therefore poor overall thermal efficiency.

 The present invention aims to overcome this drawback.

It relates to a system of power semiconductor components cooled by circulation of a liquid, comprising - N semiconductor components, each component having externally first and second opposite flat metal faces, electrically insulated one with respect to to the other and corresponding respectively to two electrodes of the component, N being an integer, - metal blocks each having a planar surface applied to a planar face of at least one component, these blocks comprising M first blocks B1, B2 B whose flat surfaces are applied
m on the first plane faces of the components, and P second blocks b1, b2 bp whose plane surfaces are applied on the second
p plane faces of the components, M and P being whole numbers less than or equal to N, each block comprising two internal channels passing right through it, one of these channels extending from a first to a second opposite openings situated on the surface of the block, the other channel extending from a third to a fourth opposite openings located on the surface of the block, the first and third openings being located on the same side of the block, - electrical connections connecting together the different blocks, the system thus formed being able to be supplied by an electric current source, - M-1 hydraulic pipes connecting the second opening of each first block to the first opening of the first block of immediately higher order, - M-1 pipes hydraulic connecting the fourth opening of each first block to the third opening of the first block of immediately higher order, - P-1 hydraulic lines connecting the second opening of each a second block at the first opening of the second block of immediately higher order, - Pl hydraulic pipes connecting the fourth opening of each second block to the third opening of the second block of immediately higher order - and a hydraulic pipe, one end of which is connected at the first opening of the first block B1 to introduce said liquid into this block, characterized in that it further comprises - a hydraulic pipe connecting the second opening of the first block Bm to the fourth opening of the second block bp, - a hydraulic pipe connecting the fourth opening of the first block B to the second opening of the second block b
m P - a hydraulic pipe connecting the first opening of the second block b1 to the third opening of the second block b1 - and a hydraulic pipe, one end of which is connected to the third opening of the first block B1 to collect said liquid.

 According to a particular embodiment of the system according to the present invention, at least one first block has a flat surface applied at the same time on two first flat faces of two different components. Likewise, at least one second block may comprise a flat surface applied at the same time to two second square faces of two different components.

 When the system comprises an electrical protection circuit comprising at least one branch in which a resistor is connected in series, the two ends of this branch being respectively connected to the two electrodes of a component, the resistor comprises a metal casing connected to a terminal of the resistor and provided with a flat face applied to another flat external surface of a metal block, the latter being itself applied to a flat face of said component.

 Finally, the system may also include - a heat exchanger capable of cooling the liquid leaving the system, the inlet of this exchanger being connected to the other end of the hydraulic pipe, one end of which is connected to the third opening of the first block B1 , the outlet of this exchanger being connected to the other end of the hydraulic pipe, one end of which is connected to the first opening of the block B1 - and a pump connected in series with said exchanger, in order to circulate the liquid, from the exchanger to block B1.

 Several particular embodiments of the object of the present invention are described below, by way of example, with reference to the appended drawings in which - FIG. 1 represents a system of known type comprising three power diodes connected electrically in series, these diodes being provided with cooling blocks crossed in series by a liquid, - Figure 2 shows a hydraulic connection mode against the current, of known type, in a system of six power diodes, - Figure 3 represents a hydraulic connection mode, according to the invention, in a system of six power diodes, - Figure 4 is an electrical diagram of a system of six thyristors connected in series, this system being provided with a protection circuit electric, - Figure 5 partially shows a system according to the invention, corresponding to the diagram of Figure 4, in which certain cooling blocks are common to two thyristors, the resistors of c electrical protection circuit being fixed on these common blocks, - figure 6 is a diagram of electrical connection of a system of six antiparallel thyristors two by two, this system being provided with an electrical protection circuit - and figure 7 represents partially a system according to the invention, corresponding to the diagram of FIG. 6, in which each of the six cooling blocks is common to two thyristors, the resistances of the electrical protection circuit being fixed on three of these blocks.

 The known system represented in FIG. 1 comprises three identical elements 1, 2 and 3 each comprising a semiconductor component constituted by a cylindrical disc 4 in which is housed a silicon wafer forming a semiconductor junction p-n. The two flat metal faces 5 and 6 of the disc 4 correspond respectively to the anode and to the cathode of a power diode. Between the faces 5 and 6 is disposed an insulating ceramic sleeve surrounding the silicon wafer. Each element further comprises two metal blocks 7 and 8 made of copper or aluminum. These blocks of parallelepiped shape are applied strongly respectively on the faces 5 and 6 of the disc by mechanical members not shown in order to ensure good thermal and electrical contact between the blocks and the faces of the disc. block is formed an internal channel such as 9 passing through block 7, right through. In FIG. 1, the channels 9 are rectilinear and substantially parallel to the contact surfaces between the blocks and the disc.

 Each channel opens out through two openings on the surface of the block.

The openings of the different blocks are connected together by flexible hydraulic lines 10 made of an electrically insulating material. These pipes allow a coolant to circulate in the channels. This can advantageously consist of treated water to obtain good electrical insulation and avoid corrosion phenomena.

 The connection of the hydraulic lines, shown in FIG. 1, makes it possible to circulate the cooling water in series successively in the blocks 7 and 8 of the element 1, then in the blocks 11 and 12 of the element 2, and finally in blocks 13 and 14 of element 3.

 The water having passed through the block 14 is led by a pipe 15 to the inlet of a heat exchanger 16, the outlet of which is connected, through a circulation pump 17, to the inlet opening of the channel 9 by lines 18 and 19.

 A conductive strip 20 electrically connects the block 8 to the block 11 which is applied to the anode face of the disc of the element 2. Similarly a conductive strip 21 connects the block 12 to the block 13 which is applied to the anode face of the disc of element 3. The two plus and minus terminals of an electric current source 22 are electrically connected to blocks 9 and 14 respectively.

 A large current flows through the diodes of elements 1, 2 and 3 connected in series. The heat released by the passage of this current is transmitted by conduction to the different blocks. The circulation of water caused by the pump 17 allows the heat energy of the blocks to be removed, the water leaving the block 14 being cooled in the heat exchanger 16.

 As already indicated, the mode of hydraulic connection in series, illustrated by FIG. 1, has the drawback of causing different operating temperatures for the three diodes, the temperature increasing from element 1 to element 3.

 FIG. 2 schematically shows a known hydraulic connection, said to be against the current, in a system with six elements 23, 24, 25, 26, 27 and 28 similar to those of FIG. 1, each element each comprising a semiconductor component 75 and two cooling blocks.

To make the figure clearer, the electrical connection between blocks as well as the hydraulic and electrical supply of the system have not been shown. Each block 29, 3Q associated with an element 23 comprises two substantially parallel channels 31-32 and 33-34.

 One end of an inlet pipe 35 is connected to an opening of the channel 31. Then hydraulic pipes are arranged so that the cooling water leaving the channel 31 passes successively in series from blocks 36 to 40 belonging to the elements 24 to 28 along one of the channels of these different blocks.

 The water leaving the block 40 is brought by a pipe 41 in the other pipe of the block 40, in the opposite direction to the previous direction, then successively crosses the blocks 40, 39, 38, 37, 36 and 29. A pipe 42 leads the water leaving the block 29 in the pipe 33 of the element 23. Then pipes are provided so that the cooling water passes in series through the other blocks 43 to 47 in the initial direction along one of the channels of these blocks. The water leaving the block 47 is brought back into this block by a pipe 48 and crosses these blocks in the opposite direction to exit the channel 34 along a pipe 49.

 If the temperature of the water entering the block 29 via the line 35 is equal to 400C, it can be seen that the water leaving the block 29 via the line 42 is at a temperature of 580C while the water leaving the block 30 is at a temperature of 760C in line 49.

 This gives an average temperature for block 29 of 490C, which is also observed on blocks 36 to 40. The average temperature for block 30 is 670C, as well as for blocks 43 to 47.

 The temperature of the junction of each of the components, which is substantially equal to the average of the temperatures of the adjacent blocks, is equal to 580C for each of the six components.

 However, the temperature difference of 180C which exists between the two faces of each component creates an asymmetry of heat exchange which is detrimental to the overall cooling efficiency.

 FIG. 3 is a diagram of the hydraulic connection of a system according to the invention comprising six elements shown one above the other, each comprising a power semiconductor component 76. One of the blocks of each element, called the first block , is located to the left of the figure, and the other block, called the second block, is located to the right of the figure. As in the case of FIG. 2, the electrical connections between the blocks, as well as the means of electrical and hydraulic supply of the system, quite similar to those of FIG. 1, have not been shown.

 Each block has two rectilinear internal channels substantially parallel to each other, each extending vertically between two opposite openings located on the surface of the block. Thus the first block 56 of the element 50 comprises a channel 57 extending from a first opening 58 to a second opening 59, this block 56 also comprising another channel 60 extending from a third opening 61 to a fourth opening 62. The first and third openings of each block are located on the same side of the block, while the second and fourth openings are located on the other side.

 Similarly, the second block 63 of the element 50 comprises an internal channel extending from a first opening 64 to a second opening 65, and another internal channel extending from a third opening 6 to a fourth opening 67 .

 We see that the system shown in Figure 3 includes hydraulic lines such as 68 connecting the second opening of each first block of the element 51 to the first opening of the first block of the element 52 immediately above. This system also includes hydraulic lines such as 69 connecting the fourth opening or each first block of the element 51 to the third opening of the first block of the element 52 immediately above.

 This # system further includes - an inlet hydraulic line 70 leading to the first opening 58 of the block 56 of the element 50, - a hydraulic line 71 connecting the second opening of the first block of the element 55 to the fourth opening of the second block of the element 55, - a hydraulic pipe 72 connecting the third opening 66 of the block 63 of the element 50 to the first opening 64 of this block 63, - a hydraulic pipe 73 connecting the second opening of the second block of the element 55 at the fourth opening of the first block of the element 55 - and a pipe 74 starting from the opening 61 of the first block 56 of the element 50 and leading to a heat exchanger not shown.

 It can be seen in FIG. 3 that the cooling water first crosses all the first blocks of the elements 50 to 55, then all the second blocks of the elements 55 to 50; after passing through the pipe 72, the water then leaves in the opposite direction to pass through again successively all the second blocks of the elements 50 to 55 and all the first blocks of the elements 55 to 50.

 It is then found that the average temperature of each first or second block is established at an identical average value, even if the amount of heat to be removed varies from one block to another and from one element to another.

 As an indication, if the temperature of the water entering line 70 and 400C, the temperature of the water leaving line 74 is 760 C, and the average temperature of each of the first or second blocks is 580C .

 The diagram in FIG. 4 represents six thyristors (77 to 82) electrically connected in series. In parallel to each thyristor is connected a branch comprising in series a resistor (83 to 88) and a capacitor (89 to 94). These branches form an electrical protection circuit against overvoltages. The supply circuits of the auxiliary electrodes of these thyristors have not been shown to simplify the figure.

 FIG. 5 partially represents a system of power semiconductor components according to the invention, corresponding to the diagram of FIG. 4.

 This system is also formed of elements each comprising two metal blocks associated with a semiconductor component. This system comprises six second blocks 95 to 100 similar to those of FIG. 3; but the first blocks are grouped two by two so as to form three first elongated blocks 101 to 103, each of these blocks bearing at the same time on two semiconductor components electrically connected in series.

Thus, the block 101 relates both to the component 77, on the cathode side, and to the component 78, on the anode side. This arrangement simplifies the electrical connections of the system. In fact, these only have two bars 104 and 105 for connecting the strong current, the two terminals of the electric power source being able to be connected to blocks 95 and 100 respectively.

 We also see in Figure 3 that the hydraulic connection diagram is similar to that of Figure 3, but is also simplified as a result of the removal of six hydraulic lines, this removal resulting directly from the grouping two by two of the first blocks.

 It also appears in FIG. 3 that the resistors 83 to 88 of the protection circuit are fixed on the external surface of the blocks 101 to 103.

These resistors are subjected during operation to a relatively significant heating
They each comprise an external metal casing capable of conducting heat, this casing being electrically connected to a terminal of the resistor.

 The envelope has a flat surface which is applied to a flat surface of the block, so as to make both good electrical contact and good thermal contact. This arrangement simplifies the electrical connections of the system. The metal blocks on which these resistors are fixed ensure efficient cooling of the resistors.

 To simplify FIG. 5, the capacitors which do not heat up significantly in operation have not been shown.

 We see that the device shown in Figure 5 has the same advantages as that of Figure 3: the average operating temperatures of the different components are equal to each other, and for each component, the average temperatures of the two adjacent blocks of the same element are also substantially identical.

 FIG. 6 is a diagram showing three groups of two antiparallel thyristors 106-107, 108-109, 110-111, these groups being connected in series. In parallel to each group is connected a branch comprising in series a resistor 112 to 114 and a capacitor 115 to 117, these branches forming an electrical protection circuit for the thyristors.

 FIG. 7 partially represents a system of power semiconductor components according to the invention, corresponding to the diagram of FIG. 6, the capacitors not having been shown.

 This system comprises six elongated blocks 118 to 123. Each of these blocks is applied at the same time to two faces of two different semiconductor components, electrically connected in series. Thus, the block 121 is applied both to the anode face of the thyristor 106 and to the cathode face of the thyristor 107. Each assembly such as 108-109-119-122, formed of two blocks applied to the faces of two components, corresponds to a group of two antiparallel thyristors. The electrical connections between the groups are made by a strip 124 connecting the blocks 121 and 122 and a strip 125 connecting the blocks 119 and 120. The electrical supply of the system can be carried out by connection of the two terminals of a source of electric current at blocks 121 and 123.

 The hydraulic connection of the system is similar to that of FIG. 3. Of course, each grouping of two blocks in a single block allows the elimination of two hydraulic lines. The diagram in FIG. 7 therefore contains 12 fewer hydraulic pipes than that in FIG. 3. The hydraulic inlet 126 and outlet 127 pipes can be connected to a hydraulic supply assembly comprising in series a pump and a heat exchanger .

 Finally the resistors 112 to 114, of a type analogous to that of the resistors 83 to 88 of FIG. 4, are fixed respectively on plane surfaces of the blocks 118 to 120.

 Despite the presence of these resistors, it can be seen that the average temperature of the blocks during operation does not vary from one block to another.

 It can therefore be seen that the system according to the invention makes it possible to reduce the cost price by facilitating the hydraulic and electrical connection between the blocks.

 These can be simple copper parallelepipeds pierced with two straight holes right through for the passage of water. The system according to the invention also makes it possible to make the cooling of the power semiconductor components more homogeneous.

 The system according to the present invention can be applied for example to the production of reactive energy compensation systems in high-voltage substations.

Claims (4)

1 / System of power semiconductor components cooled by circulation of a liquid, comprising - N semiconductor components, each component having externally first and second opposite flat metal faces, electrically insulated from one another and corresponding respectively to two electrodes of the component, N being an integer, - metal blocks each having a planar surface applied to a planar face of at least one component, these blocks comprising M first blocks B1, B2 Bm whose planar surfaces are applied to the first plane faces of the components, and P second blocks b1, b2 bp whose plane surfaces are applied to the second plane faces of the components, M and P being whole numbers less than or equal to N, each block comprising two channels internal through it right through, one of these channels extending from a first to a second opposite openings located on the surface of the block , the other channel extending from a third to a fourth opposite openings located on the surface of the block, the first and third openings being located on the same side of the block, - electrical connections connecting the different blocks together, the system thus formed being able to be supplied by a source of electric current, - M-1 hydraulic pipes connecting the second opening of each first block to the first opening of the first block of immediately higher order, - M-1 hydraulic pipes connecting the fourth opening of each first block at the third opening of the first block of immediately higher order, - P-1 hydraulic pipes connecting the second opening of each second block to the first opening of the second block of immediately higher order, - P-1 pipes hydraulic connecting the fourth opening of each second block to the third opening of the second block of immediately higher order - and a pipeline on hydraulic one end of which is connected to the first opening of the first block B1 to introduce said liquid into this block, characterized in that it further comprises - a hydraulic pipe (71) connecting the second opening of the first block Bm to the fourth opening of the second block bp, - a hydraulic line (73) connecting the fourth opening of the first block Bm to the second opening of the second block bp, - a hydraulic line (72) connecting the first opening of the second block b1 (63) to the third opening of the second block b1 - and a hydraulic pipe (74) one end of which is connected to the third opening of the first block B1 (56) to collect said liquid. 2 / System according to claim 1, characterized in that at least a first block (101) has a flat surface applied at the same time on two first flat faces of two different components (77, 78). 3 / System according to claim 1, characterized in that at least a second block (122) has a flat surface applied at the same time on two second flat faces of two different components (108, 109).  h / system according to claim 1, characterized in that, this system comprising an electrical protection circuit comprising at least one branch in which a resistor (113) is connected in series, the two ends of this branch being connected respectively to the two electrodes of a component (108), the resistor comprises a metal casing connected to a terminal of the resistor and provided with a flat face applied to another flat external surface of a metal block (119), the latter being applied to it even on a flat face of said component (108).  5 / System according to claim 1, characterized in that it further comprises - a heat exchanger (16) capable of cooling the liquid leaving the system, the inlet of this exchanger being connected to the other end of the hydraulic pipe one end of which is connected to the third opening of the first block B1, the outlet of this exchanger being connected to the other end of the hydraulic pipe, one end of which is connected to the first opening of the block B1 - and a pump (17) connected in series with said exchanger, in order to circulate the liquid, from the exchanger (16) to the block B1.