Description:FIELD OF THE INVENTION:

[0001] The present invention generally relates to electronic controller modules used in electric vehicles. More specifically, the present invention relates to gas filled electronic controller modules for enhancing its thermal performance.

BACKGROUND:

[0002] The automobile industry is encountering a new evolution in this era and electric vehicle (EV) motors have become a mandate. Therefore, the power requirements of electric vehicle automobiles have become substantial which demands efficient electronic controller modules.

[0003] The electronic controller module in the electric vehicle operates between the batteries and the motor to control the electric vehicle's speed and acceleration. The conventional electronic controller modules used in EV motors have 10 – 30 MOSFETs approximately with each MOSFET producing 30W of heat. i.e., on an average, the MOSFETs in the electronic controller module produces 200W to 700W of heat. Apart from the MOSFETs, Capacitors also produce approximately 50W to 100W of heat. These Electronic controller modules are specifically used in BSG motors, BLDC motors and occupy a space volume of 300 cm3 - 500 cm3 approximately and are prone to thermal failure. Further, in the existing products, the air present inside the sealed modules does not conduct much heat.

[0004] The controller modules are sealed and air tight to prevent dust and other foreign particles from entering the printed circuit board (PCB)/MOSFET area. The volume occupied by air in an electronic controller module is 100 cm3 - 300 cm3. This means that the mass of the air occupied in this volume at sea level conditions is 122 mg - 367 mg exerting a pressure of 1 atm (101325 Pa) on the surrounding components. This greatly affects the thermal performance of the electronic controller.

[0005] In order to overcome the aforementioned drawbacks, the present invention proposes a relatively cool electronic controller module using helium gas for better thermal performance of the controller. The air inside the controller module is replaced by helium gas since helium is naturally less dense than air. The helium gas has a density of 0.164 kg/m3 and thermal conductivity of 0.1906 W/mK. This makes it a better thermal conductor and thereby helps to improve convection of heat.

OBJECTIVES OF THE INVENTION:

[0006] The primary objective of the present invention is to provide a relatively cool electronic controller module using helium gas for better thermal performance of the controller.

[0007] Another objective of the present invention is to enhance convection of heat around the electronic controller module.

[0008] Yet another objective of the present invention is to improve reliability of the electronic controller module.

[0009] Further another objective of the present invention is to include a one-way pressure valve in the bottom of the controller for holding the helium gas inside the housing and preventing it from escaping to the environment. Also, the one-way pressure valve is used to fill the helium gas inside the controller housing, when it gets depleted over the time.

[0010] Moreover another objective of the present invention is to include a pressure sensor or pressure gauge to monitor the helium gas pressure inside the controller housing.

[0011] Furthermore another objective of the present invention is to include a display and alert system comprising a visual or audio indication regarding the current static pressure of the helium gas inside the housing, and provides visual or audio indication to alert when the pressure is dropped below the predetermined value.

[0012] Other objects and advantages of the present invention will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the invention.

SUMMARY:

[0013] To achieve the aforementioned objectives, the present invention provides a relatively cool electronic controller module of an electric vehicle, comprising: an enclosure including: PCB, plurality of MOSFETs, capacitors, heat fins, wires and solder legs, wherein the enclosure is filled with helium gas to improve the thermal performance of the controller; a one-way pressure valve mounted on the bottom of the enclosure for holding and filling the helium gas in the enclosure; and a pressure gauge with an alert system to measure the static pressure of the gas inside the enclosure.

[0014] In accordance with the present invention, the enclosure includes a display system for displaying pressure values of gas inside. Further, the controller includes a sensor for sensing the pressure of the gas inside the enclosure.

[0015] Furthermore, the alert system includes a visual indication or audio indication to alert when the pressure is dropped below the predetermined value and indicates when the time to refill the gas inside the enclosure arrives.

[0016] Since helium gas is relatively lighter than air and thermally more conductive than air, it makes more viable for usage in electronic controller module and also improves the reliability of the module.

[0017] The arrangement of the present invention has other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following brief description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0018] The present invention will be better understood fully from the detailed description that is given herein below with reference to the accompanying drawings of the preferred embodiments of the present invention, which, however should not be deemed to be a limitation to the invention to the specific embodiments, but are for the purpose of explanation and understanding only.

[0019] FIG 1. illustrates the electronic controller module;
[0020] FIG. 2 (a) illustrates the perspective view of the controller;
[0021] FIG. 2 (b) shows the side view of mid plane cut section of the controller filled with helium gas;
[0022] FIG. 3 shows the graphical representation of thermal performance comparing air and helium; and
[0023] FIG. 4 shows the pressure sensor in the electronic controller.

REFERENCE NUMERALS:

1 – Controller housing
1a – Power PCB
1b – Controller PCB
2 – MOSFET
2a – MOSFET legs
3 – Heat fins
4 – TIM (Thermal interface material)
5 – Pressure gauge
6 – One way valve
8 – Power Terminals
200 – PCBs in Controller
202 – Pressure sensor
204 – Helium filling valve under the controller

DETAILED DESCRIPTION OF THE INVENTION:

[0024] The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0025] The present invention provides a relatively cool electronic controller module of an electric vehicle for better thermal performance.

[0026] Referring to FIG. 1, the electronic controller module comprises: a controller housing (1) where controllers for electric vehicle (EV) motors usually are contained in a ADC12 housing heat fins casted on the same housing and PA66 cover on the other side; The controller housing (1) or enclosure is filled with helium gas; a power PCB (1a) which mounts the MOSFETs and other pins where the actual switching of DC to AC and AC to motor suitable current / voltage combination takes place; a controller PCB (1b) which contains the DC power input lines from the battery and a microcontroller which holds the software required to run / control the motor; heat fins (3) to improve convection as MOSFETs (2) undergo its full function, enormous amounts of switching loss takes place leading to high power loss density. i.e., MOSFET losses certain Watts of power to the TIM paste and heat sink; Thermal interface material (TIM) (4) conductive paste is thermally conductive and forms as an electrical insulation barrier; a one way pressure valve (6) mounted on the bottom of the housing, so that the gas does not have the tendency to flow downwards and leave the system and this one way valve (6) ensures that the gas flow is arrested to flow only in upward direction; and pressure gauge (5) measures the static pressure and consistency of the helium gas inside the system and there is an indicator to ensure the value of pressure inside. The power terminals (8) are provided to operate the controller by connecting it to the power source or battery of the electric vehicle.

[0027] In the present invention, the air inside the housing of the controller is replaced by helium gas which is 7.5 times lighter than air and 6 times more conductive than air. In this invention, a one way pressure valve and pressure gauge with visual aid to monitor the pressure, are all added to ensure the intent of engineering.

[0028] FIG. 2 (a) and FIG. 2 (b) illustrate the perspective view and side view of mid plane cut section of the controller.

[0029] Curvatures in the terminals and pins are removed. All fasteners are removed and the holes are filled with same adjacent material. Pins on the PCB boards and busbars are removed for simplicity of the model. Curvatures of the external part of the duct is simplified without compromising the intended air flow. 95 % of the geometric similarity is maintained. Peak Load is considered for thermal simulation where the MOSFETS are producing the heat as shown in FIG. 3. By referring to FIG. 3, it is evident that there is 25oC drop in MOSFET temperature with helium filled controllers thus improving convective heat transfer. The graph and tabular column mathematically prove that helium filled electronic controllers have better thermal performance than conventional air-filled controllers.

[0030] The heat produced by MOSFETs, solder legs, capacitors are transferred by convective heat transfer. Helium is better compared to air in terms of convective heat transfer properties.

[0031] In accordance with the present invention, the pressure gauge includes an indicator for monitoring the gas pressure. As shown in FIG. 4, the electronic controller with PCBs (200) includes a pressure sensor (202) sensor for sensing the pressure and also includes an alert system for providing a visual/light indication or audible/speaker alert when the pressure is dropped below the predetermined value. The pressure sensor (202) or pressure guage may also displays the pressure of the gas inside the controller housing (1). The one-way valve (204) in the controller is responsible for holding gas inside the housing and allows to refill again when required. The controller also includes a display system for displaying pressure values of gas inside. The one-way pressure valve (204) is present in the bottom of the controller for holding the helium gas inside the controller housing (1) and preventing it from escaping to the environment. The display and alert system comprising a visual and/or audio indication regarding the current static pressure of the helium gas inside the housing, and the time to refill the helium gas, when the pressure is dropped below the predetermined value.

[0032] In the present invention, since the air is being replaced by helium, the helium gas will occupy the same volume of 100 cm3 - 300 cm3 but the mass of helium will be 16.4 mg – 49.2 mg exerting a pressure of almost 1 atm (101507 Pa) on the surrounding components.

[0033] Both the gases “Air” and “Pure Helium” follow ideal gas laws (PV = nRT or P = ?RT). At room temperature 25 °C or 298 K, the gas constant of Air is 287 J/kg-K and the gas constant of helium is 2077 J/kg-K. Advantageously, the density of helium is 0.164 kg/m3 which makes it better for thermal performance and thereby improves reliability of the electronic controller modules.

[0034] After carrying out several Computational Fluid Dynamics (CFD) simulations, it is found that helium filled controllers are commercially viable solution for increasing the thermal performance of the electronic controllers of electric vehicles since there is precisely 25°C drop in temperature if conventional electronic controller modules are filled with helium instead of air.

[0035] Hence, the present invention can extend the thermal spectrum of the current functional limits and also extend the range of operation of the controller as the MOSFET heats drop down by 25% compared to the conventional air-filled controller design.

[0036] While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope of the invention as claimed. , Claims:WE CLAIM:

1. An electronic controller of an electric vehicle, comprising:
a. a controller housing (1) includes one or more PCB assemblies (1a, 1b);
b. said atleast one PCB assembly comprises plurality of MOSFET’s (2) mounted on it;
c. a one-way pressure valve (6);
d. a pressure guage (5);
e. wherein said controller housing (1) is filled with helium gas to improve thermal performance of the controller;
f. wherein said one-way pressure valve (6) is mounted on the bottom of the controller housing (1) for holding and filling the helium gas inside the controller housing (1); and
g. wherein said pressure guage (5) is to measure the static pressure of the helium gas inside the controller housing (1).

2. The electronic controller as claimed in claim 1, wherein the controller housing (1) includes plurality of heat fins (3) mounted outside the controller housing.

3. The electronic controller as claimed in claim 1, wherein the controller housing (1) includes a display system for displaying pressure values of gas inside.

4. The electronic controller as claimed in claim 1, includes a pressure sensor (202) for sensing and displaying the pressure of the gas inside the controller housing (1).

5. The electronic controller as claimed in claim 1, wherein the alert system includes a visual indication and/or audio indication to alert when the pressure is dropped below the predetermined value and indicates the time to refill the gas inside the controller housing.