Switch cooling system for inverters

Abstract

Switch cooling system that includes: a coolant channel (604); a switch (316) of an inverter module (256) disposed in the coolant channel (604), configured to be immersed in the coolant in the coolant channel (604), and including: a first terminal arranged on a first level and configured to be connected to a direct current (DC) reference potential; a second terminal disposed on a second plane and configured to be connected to an alternating current (AC) reference potential; a gate (524), an emitter (528) and a collector (532) arranged between the first and second levels; first cooling features (516) extending from the first and second planes, in direct contact with the first port, and configured to permit coolant flow therethrough; and second cooling features (516) extending from the first cooling features (516), the first level, and the second level, which are in direct contact with the second port, and which are configured to allow coolant flow therethrough; characterized in that the switch cooling system further comprises a second switch (320) of the inverter module (256) disposed in the coolant channel (604), configured to be immersed in the coolant in the coolant channel (604), and including: a third terminal arranged on a third level and configured to be connected to a second DC reference potential; a second gate (536), a second emitter (540), and a second collector (544) disposed between the second and third levels; and third cooling features (516) extending from the second and third levels, in direct contact with the third port, and configured to permit coolant flow therethrough.

Description

INTRODUCTION

[0001] The present invention relates to vehicle drive systems and, in particular, to a switch cooling system according to the preamble of claim 1 of an inverter module, as is essentially known from JP 2009 - 159 815 A.

[0002] Some vehicle types contain only an internal combustion engine that generates drive torque. Electric vehicles may not contain an internal combustion engine and may rely on one or more electric motors for propulsion.

[0003] Hybrid vehicles contain both an internal combustion engine and one or more electric motors. Some types of hybrid vehicles use the electric motor and internal combustion engine in an effort to achieve greater fuel efficiency than using only the internal combustion engine. Some types of hybrid vehicles use the electric motor and internal combustion engine to achieve greater torque output than the internal combustion engine could achieve alone.

[0004] Some example types of hybrid vehicles include parallel hybrid vehicles, series hybrid vehicles, and other types of hybrid vehicles. In a parallel hybrid vehicle, the electric motor operates in parallel with the prime mover to combine the power and range advantages of the prime mover with the efficiency and regenerative braking advantages of the electric motors. In a series hybrid vehicle, the prime mover drives a generator to produce electricity for the electric motor, while the electric motor drives a transmission. This allows the electric motor to assume some of the power responsibilities of the prime mover, allowing the use of a smaller and potentially more efficient prime mover. SUMMARY

[0005] According to the invention, a switch cooling system is presented which is characterized by the features of claim 1.

[0006] The switch cooling system comprises: a coolant channel; a switch of an inverter module disposed in the coolant channel, configured to be immersed in the coolant in the coolant channel, and including: a first terminal disposed at a first level and configured to be connected to a direct current (DC) reference potential; a second terminal disposed at a second level and configured to be connected to an alternating current (AC) reference potential; a gate, an emitter, and a collector; first cooling features extending from the first and second levels, in direct contact with the first terminal, and configured to allow coolant flow therethrough;and second cooling features extending from the first cooling features, the first level, and the second level, that are in direct contact with the second terminal, and that are configured to allow coolant flow therethrough. The switch cooling system further comprises a second switch of the inverter module disposed in the coolant channel, configured to be immersed in the coolant in the coolant channel, and including: a third terminal disposed on a third level and configured to be connected to a second DC reference potential; a second gate, a second emitter, and a second collector disposed between the second and third levels;and third cooling features extending from the second and third levels, in direct contact with the third port, and configured to permit coolant flow therethrough;

[0007] In other features, the first and second levels are parallel.

[0008] In further features, the first cooling features extend perpendicularly from the first and second planes.

[0009] In further features, the second cooling features extend perpendicularly from the first and second planes.

[0010] In further features, an electrical insulator is disposed between (a) the gate, the emitter, and the collector and (b) the second gate, the second emitter, and the second collector.

[0011] In further features, first, second, and third electrical conductors are electrically connected to the first, second, and third terminals, extending through the coolant channel to the exterior of the coolant channel.

[0012] In further features, the first cooling features include elements extending perpendicular to the first and second planes.

[0013] In further features, the first features include: several parallel plates; and posts that separate the plates from each other.

[0014] In further features, the posts extend perpendicular to the parallel plates.

[0015] In other features, the posts are cylindrical.

[0016] In other features, the posts all have the same diameter.

[0017] In other features, the posts all have the same spacing.

[0018] In further features, the posts include first posts having a first diameter and second posts having a second diameter.

[0019] In further features, the first posts have a first spacing and the second posts have a second spacing, wherein the first spacing is different than the second spacing.

[0020] In further features, the first cooling features include: a first layer including an inlet, an outlet, a first portion fluidly connected to the inlet, and a second portion fluidly connected to the outlet; a second layer including a third portion fluidly connected to the first and second portions of the first layer; and a third layer including a fourth portion fluidly connected to the first and second portions.

[0021] In further features, the first cooling comprises: two parallel plates; and a helical element having a first direction of rotation and arranged between the two parallel plates.

[0022] In further features, the first cooling features further include: a second helical element having a second direction of rotation and disposed between the two parallel plates.

[0023] In other features, the second direction of rotation is different from the first direction of rotation.

[0024] In further features, the first cooling features include: a first material having uniform openings configured to allow coolant flow therethrough; and a second material having non-uniform openings configured to allow coolant flow therethrough.

[0025] Further areas of applicability of the present invention will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are provided for purposes of illustration only. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be more fully understood from the detailed description and the accompanying drawings, in which: Fig. 1 shows a functional block diagram of an exemplary vehicle system; Fig. 2 shows a functional block diagram of an exemplary drive control system; Fig. 3 is a schematic diagram including an exemplary implementation of an inverter module and a battery; Fig. 4 is a perspective view of an exemplary implementation of switches of a branch of the inverter module; Fig. 5 is an exploded perspective view of the exemplary switches of the branch according to Fig. 4; Fig. 6 is a side cross-sectional view of an exemplary implementation of a coolant channel and the switches of the branch; Fig. 7 a three-dimensional perspective view of the exemplary coolant channel and the switches of the branch according to Fig. 6; Fig. 8 and Fig. 9 are perspective views of exemplary cooling features and a bottom view of an exemplary plate of a cooling feature; Fig. 10-14 perspective views of exemplary cooling features; and Fig. 15 and Fig. 16 functional block diagrams of exemplary cooling systems.

[0027] In the drawings, reference numerals may be used multiple times to identify similar and / or identical elements. The dimensions of features in the drawings may not be to scale. DETAILED DESCRIPTION

[0028] A vehicle's internal combustion engine combusts air and fuel within cylinders to produce drive torque. The engine may deliver torque to the vehicle's wheels via a transmission. Some vehicle types may not contain an internal combustion engine, or the engine may not be mechanically coupled to the vehicle's drivetrain.

[0029] An electric motor may be mechanically coupled to a transmission shaft. Under some circumstances, a vehicle control module may input power from a battery to the electric motor to cause the electric motor to output torque for vehicle propulsion. Under other circumstances, the control module may disable power flow to the electric motor and allow the transmission to drive the rotation of the electric motor. The electric motor generates power when driven by the transmission. The power generated by the electric motor may be used to charge the battery if a voltage generated across the electric motor is greater than a voltage of the battery. The control module switches one or more switches of an inverter module to input power from the battery to the electric motor.

[0030] The switches (e.g., the terminals) become relatively hot during switching. According to the present invention, the switches are immersed in a cooling fluid (e.g., a dielectric fluid) to cool the switches. The switches include cooling features in contact with the terminals to increase heat transfer away from the terminals and the switches.

[0031] In Fig. 1 illustrates a functional block diagram of an exemplary vehicle system. While a vehicle system for a hybrid vehicle is shown and described, the present invention is also applicable to electric vehicles that do not include an internal combustion engine, fuel cell vehicles, autonomous vehicles, and other vehicle types. Furthermore, while the example of a vehicle is provided, the present application is also applicable to non-vehicle implementations that include one or more switches.

[0032] An engine 102 may combust an air / fuel mixture to produce drive torque. An engine control module (ECM) 114 controls the engine 102. The ECM 114 may, for example, control the actuation of engine actuators, such as a throttle valve, one or more spark plugs, one or more fuel injectors, valve actuators, cam phasers, an exhaust gas recirculation (EGR) valve, one or more boost devices, and other suitable engine actuators. In some vehicle types (e.g., electric vehicles), the engine 102 may be omitted.

[0033] The engine 102 may output torque to a transmission 195. A transmission control module (TCM) 194 controls the operation of the transmission 195. For example, the TCM 194 may control gear selection within the transmission 195 and one or more torque-transmitting devices (e.g., a torque converter, one or more clutches, etc.).

[0034] The vehicle system includes one or more electric motors, such as electric motor 198. An electric motor can act either as a generator or as a motor at a given time. When acting as a generator, an electric motor converts mechanical energy into electrical energy. The electrical energy can be used, for example, to charge a battery 199. When acting as a motor, an electric motor generates torque that can be used, for example, for vehicle propulsion. While the example of one electric motor is provided, the vehicle may include more than one electric motor.

[0035] An engine control module 196 controls the flow of power from the battery 199 to the electric motor 198 and from the electric motor 198 to the battery 199. The engine control module 196 supplies the electrical power from the battery 199 to the electric motor 198 to cause the electric motor 198 to output positive torque, such as for vehicle propulsion. The battery 199 may include, for example, one or more batteries and / or battery packs.

[0036] The electric motor 198 may output torque, for example, to an input shaft of the transmission 195 or to an output shaft of the transmission 195. A clutch 200 may be engaged to couple the electric motor 198 to the transmission 195 and disengaged to decouple the electric motor 198 from the transmission 195. One or more gearing devices may be implemented between an output of the clutch 200 and an input of the transmission 195 to provide a predetermined relationship between the rotation of the electric motor 198 and the rotation of the input of the transmission 195.

[0037] The engine control module 196 may also selectively convert mechanical energy of the vehicle into electrical energy. Specifically, the electric motor 198 generates and outputs power via back EMF when the electric motor 198 is driven by the transmission 195 and the engine control module 196 is not supplying power from the battery 199 to the electric motor 198. The engine control module 196 may charge the battery 199 via the power output by the electric motor 198.

[0038] In Fig. 2, a functional block diagram of an example propulsion control system is shown. A driver torque module 204 determines a driver torque request 208 based on a driver input 212. The driver input 212 may include, for example, an accelerator pedal position (APP), a brake pedal position (BPP), a cruise control input, and / or an autonomous input. In various implementations, the cruise control input may be provided by an adaptive cruise control system that attempts to maintain at least a predetermined distance between the vehicle and objects in a path of the vehicle. The autonomous input may be provided by an autonomous driving system that controls the movement of a vehicle from location to location while avoiding objects and other vehicles.The driver torque module 204 determines the driver torque request 208 based on one or more lookup tables that relate the driver inputs to the driver torque requests. The APP and BPP may be measured using one or more APP sensors and BPP sensors, respectively.

[0039] The driver torque request 208 may be an axle torque request. Axle torques (including axle torque requests) refer to torque at the wheels. As discussed further below, drive torques (including drive torque requests) are different from axle torques in that drive torques may refer to torque at a transmission input shaft.

[0040] An axle torque arbitration module 216 arbitrates between the driver torque request 208 and other axle torque requests 220. Axle torque (torque at the wheels) may be generated by various sources, including the engine 102 and / or one or more electric motors, such as the electric motor 198.Examples of other axle torque requests 220 include a torque reduction requested by a traction control system when positive wheel slip is detected, a torque increase request to counteract negative wheel slip, brake management requests to reduce axle torque to ensure that the axle torque does not exceed the ability of the brakes to hold the vehicle when the vehicle is stopped, and vehicle overspeed torque requests to reduce axle torque to prevent the vehicle from exceeding a predetermined speed. The axle torque arbitration module 216 outputs one or more axle torque requests 224 based on the results of arbitrating between the received axle torque requests 208 and 220.

[0041] In hybrid vehicles, a hybrid module 228 may determine how much of the one or more axle torque requests 224 should be generated by the engine 102 and how much of the one or more axle torque requests 224 should be generated by the electric motor 198. For simplicity, the example of the electric motor 198 is continued, but multiple electric motors may be used. The hybrid module 228 outputs one or more engine torque requests 232 to a propulsion torque arbitration module 236. The engine torque requests 232 indicate a requested torque output of the engine 102.

[0042] The hybrid module 228 also outputs a motor torque request 234 to the engine control module 196. The motor torque request 234 indicates a requested torque output (positive or negative) of the electric motor 198. In vehicles where the engine 102 is omitted (e.g., electric vehicles) or is not connected to output drive torque for the vehicle, the axle torque arbitration module 216 may output an axle torque request, where the motor torque request 234 may be equal to this axle torque request. In the example of an electric vehicle, the ECM 114 may be omitted, and the driver torque module 204 and the axle torque arbitration module 216 may be implemented within the engine control module 196.

[0043] In electric vehicles, the driver torque module 204 may input the driver torque request 208 to the engine control module 196, wherein the components related to controlling the engine actuators may be omitted.

[0044] The drive torque arbitration module 236 translates the engine torque requests 232 from an axle torque range (torque at the wheels) to a drive torque range (e.g., torque at a transmission input shaft). The drive torque arbitration module 236 arbitrates the translated torque requests with other drive torque requests 240. Examples of the other drive torque requests 240 include torque reductions requested for engine overspeed protection and torque increases requested to prevent stalling. The drive torque arbitration module 236 may output one or more drive torque requests 244 as a result of the arbitration.

[0045] An actuator control module 248 controls the actuators 252 of the engine 102 based on the drive torque requests 244. Based on the drive torque requests 244, the actuator control module 248 may, for example, control the opening of a throttle valve, the timing of the spark provided by the spark plugs, the timing and amount of fuel injected by the fuel injectors, the actuation / deactivation of cylinders, the phasing of the intake and exhaust valves, the output of one or more boost devices (e.g., turbocharger, supercharger, etc.), the opening of an EGR valve, and / or one or more other actuators of the engine. In various implementations, the drive torque requests 244 may be set or modified prior to use by the actuator control module 248, such as to create a torque reserve.

[0046] The motor control module 196 controls the switching of the switches of an inverter module 256 based on the motor torque request 234. The switching of the inverter module 256 controls the flow of power from the battery 199 to the electric motor 198. As such, the switching of the inverter module 256 controls the torque of the electric motor 198. The inverter module 256 also converts the power generated by the electric motor 198 and outputs the power to the battery 199, e.g., to charge the battery 199.

[0047] The inverter module 256 includes a plurality of switches. The motor control module 196 switches the switches to convert DC power from the battery 199 to alternating current (AC) power and feed the AC power to the electric motor 198 to drive the electric motor 198. For example, the inverter module 256 may convert the DC power from the battery 199 to n-phase AC power and feed the n-phase AC power to n (e.g., a, b, and c or u, v, and w) stator windings of the electric motor 198. In various implementations, n is equal to 3. The magnetic flux generated via the current flow through the stator windings drives a rotor of the electric motor 198. The rotor is connected to an output shaft of the electric motor 198 and drives the rotation of the output shaft of the electric motor 198.

[0048] In various implementations, one or more filters may be electrically connected between the inverter module 256 and the battery 199. The one or more filters may be implemented, for example, to filter the flow of power to and from the battery 199. A filter including one or more capacitors and resistors may be electrically connected in parallel with the inverter module 256 and the battery 199, as one example.

[0049] Fig. Figure 3 contains a schematic illustrating an example implementation of the inverter module 256 and the battery 199. The high (positive, DC+) and low (negative, DC-) sides 304 and 308 are connected to the positive and negative terminals of the battery 199, respectively. Additionally, the inverter module 256 is connected between the high and low sides 304 and 308.

[0050] The inverter module 256 includes three branches, one branch connected to each phase of the electric motor 198. A first branch 312 includes first and second switches 316 and 320. The switches 316 and 320 each include a first terminal, a second terminal, and a control terminal. Each of the switches 316 and 320 may be an insulated gate bipolar transistor (IGBT), a field effect transistor (FET), such as a metal oxide semiconductor FET (MOSFET), or another suitable type of switch. In the example of IGBTs and FETs, the control terminal is referred to as a gate.

[0051] The first terminal of the first switch 316 is connected to the high side 304. The second terminal of the first switch 316 is connected to the first terminal of the second switch 320. The second terminal of the second switch 320 may be connected to the low side 308. A node connected to the second terminal of the first switch 316 and the first terminal of the second switch 320 is connected to a first phase (e.g., a) of the electric motor 198.

[0052] The first branch 312 also includes first and second diodes 324 and 328 connected in anti-parallel to the switches 316 and 320, respectively. In other words, an anode of the first diode 324 is connected to the second terminal of the first switch 316, while a cathode of the first diode 324 is connected to the first terminal of the first switch 316. An anode of the second diode 328 is connected to the second terminal of the second switch 320, while a cathode of the second diode 328 is connected to the first terminal of the second switch 320. When the switches 316 and 320 are off (and open), the power generated by the electric motor 198 is transferred through the diodes 324 and 328 when the output voltage of the electric motor 198 is greater than the voltage of the battery 199. This charges battery 199. Diodes 324 and 328 form one phase of a three-phase rectifier.

[0053] The inverter module 256 also includes second and third branches 332 and 336. The second and third branches 332 and 336 may be identical or similar (in terms of circuit arrangement) to the first branch 312. In other words, the second and third branches 332 and 336 may each include corresponding switches and diodes, such as switches 316 and 320 and diodes 324 and 328, connected in the same manner as the first branch 312. For example, the second branch 332 includes switches 340 and 344 and anti-parallel diodes 348 and 352. A node connected to the second terminal of switch 340 and the first terminal of switch 344 is connected to a second stator winding (e.g., b) of the electric motor 198. The third branch 336 contains the switches 356 and 360 and the antiparallel diodes 364 and 368.A node connected to the second terminal of switch 356 and the first terminal of switch 360 is connected to a third stator winding (e.g., c) of electric motor 198.

[0054] Fig. 4 is an exemplary perspective view of the switches of the first branch 312 of the inverter module 256. Fig. 5 is an exploded perspective view of the switches of the first branch 312. The switches of the second and third branches 332 and 336 may be identical to the switches of the first branch 312.

[0055] An AC terminal 504 is connected to one phase of the electric motor 198. A positive DC terminal 508 is connected to the high side 304. A negative DC terminal 512 is connected to the low side 308. The AC terminal 504, the positive DC terminal 508, and the negative DC terminal 512 each include cooling features 516 extending vertically away from the switches, with a coolant flowing through the cooling features 516 to cool the switches of the first branch 312. While the positive and negative DC terminals 508 and 512 are illustrated relatively close to each other, the positive and negative DC terminals 508 and 512 are separated from each other and electrically insulated. In various implementations, an (electrical) insulator may be disposed between the positive and negative DC terminals 508 and 512.The AC terminal 504, the positive DC terminal 508, and the negative DC terminal 512 are made of an electrically conductive material, such as aluminum, copper, or another suitable type of electrically conductive material.

[0056] The diodes 324 and 328 are in the example according to Fig. 5. An insulator 520 is disposed between the first switch 316 and the second switch 320 and electrically isolates the first switch 316 from the second switch 320. The first switch 316 includes a gate 524, an emitter 528, and a collector 532. The second switch 320 includes a gate 536, an emitter 540, and a collector 544. As illustrated, the emitters 528 and 540 may include multiple emitter sections. The first and second switches 316 and 320 may be silicon switches, silicon carbide (SiC) switches, gallium nitride (GaN) switches, or another suitable switch type.

[0057] Fig. Figure 6 includes a side cross-sectional view of a coolant channel 604 and the first branch switches 312. Fig. Figure 7 includes a three-dimensional perspective view of the coolant channel 604 and the first branch switches 312. As shown, an assembly 608 containing the first branch switches 312 is disposed within the coolant channel 604. One or more spacers 612 may be implemented on an exterior side of the assembly and in contact with the interior walls of the coolant channel 604. Coolant flows through the coolant channel 604 and the cooling features 516 of the AC, positive DC, and negative DC terminals 504, 508, and 512.

[0058] As in Fig. 5, the switches may be arranged on planes. For example, the first switch 316 and the first diode 324 may be arranged on a first plane, while the second switch 320 and the second diode 328 may be arranged on a second plane. The first and second planes may be parallel. The cooling features 516 of the AC, positive DC, and negative DC terminals 504, 508, and 512 may each extend perpendicular to (normal to) the first and second planes. As shown in the Fig. 6 and Fig. 7, the leads 704 connected to the AC, positive DC, and negative DC terminals 504, 508, and 512 may extend through the coolant channel 604 to electrically connect to other components outside the coolant channel 604.

[0059] Fig. 8 is a perspective view of exemplary features 804 of the negative DC terminal 512 and a bottom view of an exemplary plate 808. The cooling features of the AC terminal 504 and the positive DC terminal 508 may be identical to the cooling features 804.

[0060] A first plate 806 is electrically conductive and may be in contact with one or more portions of one or more of the switches. The plate 806 is arranged in a plane that is horizontal to the planes of the switches.

[0061] The cooling features 804 include a plurality of plates, such as plates 808-1, 808-2, ..., 808-N, (collectively referred to as plates 808). The plates 808 are arranged on different horizontal planes that are parallel to the planes of the switches and parallel to the plane of the plate 806.

[0062] The posts 812 are formed on a bottom surface 816 of each of the plates 808 and extend away from the bottom surface 816 of each of the plates 808. The plates 808 and the posts 812 may be made of an electrically conductive material. The posts 812 of the plates 808 may extend perpendicular to the plates 808. The posts 812 may be cylindrical, such as in the example of Fig. 8. While the example of cylindrical posts is provided, the posts 812 may have any other suitable shape. The posts 812 may be formed as shown in the example of Fig. 8 have the same diameter, the same spacing, and the same distance. In various implementations, posts with two or more different diameters may be used, with two or more different post spacings and / or distances being used. Fig. 9 includes, for example, a perspective view of example features 804 of the negative DC terminal 512 and a bottom view of the example plate 808. In the example of Fig. 9, each of the plates 808 includes first posts 904 having a first diameter and second posts 908 having a second diameter. A first distance exists between the centers of the first posts 904, while a second distance, different from the first distance, exists between the centers of the second posts 908.

[0063] In the examples after the Fig. 8 and Fig. 9, a coolant can flow between the plates and between the posts to cool the switches.

[0064] In various implementations, the plates 804 and 808 may be replaced by features configured to move through several different planes parallel to the switches.

[0065] Fig. For example, Figure 10 is a perspective view of an example cooling feature 1004 of the negative DC terminal 512. The cooling features of the AC terminal 504 and the positive DC terminal 508 may be identical to feature 804.

[0066] The feature 1004 includes at least three layers arranged on different planes parallel to the planes of the switches. While the example according to Fig. 10 involves three layers, two or more layers may be used.

[0067] Fig. 10 also includes views of example upper and lower layers 1008 and an example middle layer 1012. The middle layer 1012 is disposed between the upper and lower layers 1008, such as at level 1016. The upper and lower layers 1008 are disposed above and below the middle layer 1012. The upper layer 1008 may be disposed, for example, at level 1020. The upper and lower layers 1008 may be identical. Cross-section 1024 is taken along level 1028.

[0068] The middle layer 1012 may include the inlets 1032 and the outlets 1036, a first section 1040, and a second section 1044. The coolant flows through the inlets 1032 to the first section 1040. The upper and lower layers 1008 include a third section 1048 that receives the coolant from the first section 1040 and that allows the coolant to flow to the second section 1044. The second section 1044 is fluidly connected to the outlets 1036, with the coolant flowing out through the outlets 1036. Example coolant flow paths are provided in cross-section 1024.

[0069] Fig. 11 includes a perspective view of an exemplary cooling feature 1104 of the negative DC terminal 512. The cooling features of the AC terminal 504 and the positive DC terminal 508 may be identical to the feature 1104.

[0070] Feature 1104 includes a plate 1108 disposed on a plane parallel to the planes of the switches. A support 1112 extends away from plate 1108, such as perpendicular to the plane of plate 1108. Other plates 1116 extend away from support 1112, such as perpendicular to support 1112, such that plates 1116 and support 1112 form T-shapes. Plates 1116 may be disposed along planes parallel to the plane of plate 1108. Coolant flows through the cavities between adjacent ones of the plates 1116.

[0071] One or more rotation generating elements 1120 are arranged in the cavities between adjacent plates 1116. The rotation generating elements 1120 may be spiral-shaped. As in the example according to Fig. 11, for example, two rotation-generating elements 1120 may be arranged in each cavity. The two rotation-generating elements 1120 may, for example, include a right-hand spiral and a left-hand spiral to generate a counter-rotating coolant flow, as illustrated by 1124. Alternatively, the two rotation-generating elements 1120 may include two right-hand spirals or two left-hand spirals to generate a co-rotating coolant flow, as illustrated by 1128 and 1132.

[0072] Fig. 12 includes a perspective view of an exemplary cooling feature 1204 of the negative DC terminal 512. The cooling features of the AC terminal 504 and the positive DC terminal 508 may be identical to the feature 1204.

[0073] The feature 1204 may include a plate 1206 arranged on a plane parallel to the planes of the switches. Alternating rectangular blocks of structured material 1208 and unstructured material 1212 may be arranged in rows and columns on the plate 1206. Example illustrations of the structured material 1208 are shown on the right in Fig. 12. The structured material 1208 has the same openings throughout. An exemplary illustration of the unstructured material 1212 is shown below in Fig. 12. An example of the unstructured material 1212 includes metal foam. The coolant flows through the structured material 1208 and the unstructured material 1212 to cool the switches.

[0074] Fig. 13 is a perspective view of exemplary features 1304 of the negative DC terminal 512. Fig. 13 also includes a top view of example features 1304. The cooling features of AC terminal 504 and positive DC terminal 508 may be identical to cooling features 1304.

[0075] A plate 1308 is electrically conductive and may be in contact with one or more portions of one or more of the switches. The plate 1308 is disposed on a plane that is horizontal to the planes of the switches.

[0076] The extensions 1312 are formed on the plate 1308 and extend away from the plate 1308, such as perpendicular (normal) to the plate 1308. The extensions 1312 may be made of an electrically conductive material. As shown in the plan view, the extensions 1312 form the channels 1316 when viewed from above. The coolant flows through the channels 1316 and between adjacent ones of the extensions 1312. The channels 1316 and the extensions 1312 may be wave-shaped when viewed from above, such as a semicircular wave, as in the example of Fig. 13. Alternatively, the channels 1316 and the extensions 1312 may have any other suitable shape, including any other waveform (e.g., solid wave, sawtooth wave, square wave, etc.).

[0077] In the examples after the Fig. 8 and Fig. 9 allows the coolant to flow between the plates and between the posts to cool the switches.

[0078] Fig. Figure 14 illustrates various example arrangements of switches of the inverter module 256 in the path of the coolant. As shown in the upper left, the switches may be arranged so that the switches receive the coolant sequentially. As shown in the upper right, half of the switches may receive the coolant flow in a first direction, while the other half of the switches may receive the coolant flow in a second direction. In the upper right example, the switches receive the coolant sequentially.

[0079] The example in the center left illustrates that the switches can be arranged so that each receives the coolant simultaneously. The example in the center right illustrates that half of the switches can be arranged to receive the coolant flowing in a first direction simultaneously, while the other half of the switches can be arranged to receive the coolant flowing in a second direction simultaneously.

[0080] The example below left illustrates that groups of two or more switches can be arranged to receive the coolant simultaneously, with the groups receiving the coolant at different times. The example below right illustrates that the switches can be arranged near a center wall of the coolant channel, and that the coolant can flow toward the center wall.

[0081] Fig. 15 contains a functional block diagram of an example cooling system. Heat exchanger 1504 transfers heat away from (and cools) coolant 1508 flowing through switches 1512 of inverter module 256. Coolant 1508 may be, for example, a liquid dielectric coolant or another suitable type of coolant. Heat exchanger 1504 may cool coolant 1508 using a liquid 1516 and / or a gas, such as air 1520.

[0082] The coolant 1508 may flow from the heat exchanger 1504 to one or more components 1516 or the electric motor 198. The coolant 1508 may then flow to the battery 199. The coolant 1508 may flow from the battery to one or more components 1516 or to the electric motor 198.

[0083] The coolant 1508 may then flow to the switches 1512 of the inverter module 256. The coolant may then flow to one or more components 1516 or to the electric motor 198 before returning to the heat exchanger 1504.

[0084] Fig. 16 is a functional block diagram of an example cooling system. A pump 1604 pumps the coolant when the pump 1604 is turned on. A coolant control module 1608 controls whether the pump 1604 is turned on or off. The coolant control module 1608 may also control a speed of the pump 1604.

[0085] The pump 1604 pumps the coolant to a heater 1612. The heater 1612 can be turned on to heat the coolant under certain circumstances. The coolant control module 1608 can control whether the heater 1612 is on or off. The coolant output from the heater 1608 flows to a first valve 1616. When the first valve 1616 is in a first position (0), the first valve 1616 outputs coolant to a first coolant path 1620. When the first valve 1616 is in a second position (1), the first valve 1616 outputs coolant to a second coolant path 1624.

[0086] While the example of one branch of switches is provided, the present application is also applicable to a single switch disposed in the coolant.

[0087] The coolant in the first coolant path 1620 flows through a radiator 1628 before flowing to a second valve 1632. A heat exchanger 1636 of a heating, ventilation, and air conditioning (HVAC) system of the vehicle may be used to cool the radiator. The radiator 1628 cools the coolant flowing through the radiator 1628. The coolant in the second coolant path 1624 flows through the battery 199 and the inverter switches 1512 before flowing to the heat exchanger 1504. While the example of an air-to-liquid heat exchanger is provided, the heat exchanger 1504 may be a liquid-to-liquid heat exchanger, as discussed above.

[0088] The second valve 1632 splits the coolant flow to the battery 199 and a third valve 1640. The third valve 1640 controls whether the coolant output from the second valve 1632 flows to the inverter switches 1512. The coolant control module 1608 may control the opening of the third valve 1640. The coolant output from the battery 199 may be lower than a temperature of the inverter switches 1512. Excess coolant may be stored in a tank 1644.

[0089] For a cold start of the vehicle, the coolant control module 1608 may turn on the heater 1612, move the first valve 1616 to the second (1) position, and close the third valve 1640. During normal operation, the coolant control module 1608 may turn off or leave the heater 1612 off, move the first valve 1616 to the second (1) position, and close the third valve 1640. For cooling (the battery 199 and the inverter switch 1512), the coolant control module 1608 may turn off or leave the heater 1612 off, move the first valve 1616 to the first (0) position, and close the third valve 1640. To cool the inverter switches 1512 (and not the battery 199), the coolant control module 1608 may turn off or keep the heater 1612 off, move the first valve 1616 to the first (0) position, and open or vary an opening of the third valve 1640.

Claims

[1] Switch cooling system, which includes: a coolant channel (604); a switch (316) of an inverter module (256) disposed in the coolant channel (604), configured to be immersed in the coolant in the coolant channel (604), and including: a first terminal arranged on a first level and configured to be connected to a direct current (DC) reference potential; a second terminal disposed on a second plane and configured to be connected to an alternating current (AC) reference potential; a gate (524), an emitter (528) and a collector (532) arranged between the first and second levels; first cooling features (516) extending from the first and second planes, in direct contact with the first port, and configured to permit coolant flow therethrough; and second cooling features (516) extending from the first cooling features (516), the first level, and the second level, which are in direct contact with the second port, and which are configured to allow coolant flow therethrough; characterized by , that the switch cooling system further comprises a second switch (320) of the inverter module (256) disposed in the coolant channel (604), configured to be immersed in the coolant in the coolant channel (604), and including: a third terminal arranged on a third level and configured to be connected to a second DC reference potential; a second gate (536), a second emitter (540), and a second collector (544) disposed between the second and third levels; and third cooling features (516) extending from the second and third levels, in direct contact with the third port, and configured to permit coolant flow therethrough. [2] The switch cooling system of claim 1, wherein the first and second planes are parallel. [3] The switch cooling system of claim 1, wherein the first cooling features (516) extend perpendicularly from the first and second planes. [4] The switch cooling system of claim 1, wherein the second cooling features (516) extend perpendicularly from the first and second planes. [5] The switch cooling system of claim 1, further comprising an electrical insulator (520) disposed between (a) the gate (524), the emitter (528), and the collector (532), and (b) the second gate (536), the second emitter (540), and the second collector (544). [6] The switch cooling system of claim 1, further comprising first, second, and third electrical conductors electrically connected to the first, second, and third terminals and extending through the coolant channel (604) to the outside of the coolant channel (604). [7] The switch cooling system of claim 1, wherein the first cooling features (516) include elements extending perpendicular to the first and second planes. [8] The switch cooling system of claim 1, wherein the first cooling features include: several parallel plates (808); and Posts (812) separating the plates (808) from each other. [9] The switch cooling system of claim 8, wherein the posts (812) extend perpendicular to the parallel plates (808).

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