TECHNICAL FIELD

[0001] The present subject matter relates to a high voltage system. More particularly, to an isolation of a power supply in the high voltage system for safety of electrical loads in the high voltage system.

BACKGROUND

[0002] Existing high voltage systems include a high voltage power source, an inverter, a low voltage DC-DC converter, and a high voltage electrical load, such as a motor. Such high voltage systems find applications in electric vehicles, hybrid electric vehicles, ships, etc. In the design of the high voltage systems, the high voltage power source, such as, batteries represent multiple challenges for safety. Fuses are provided within the batteries on one or both of the positive terminal and the negative terminal of the batteries to protect them from excessive currents. The interconnecting wires between the batteries and the motor witness high currents and voltage spikes. A protection device that breaks the circuit, in case of occurrence of a fault in the interconnecting wires is needed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.

[0004] Fig. 1 exemplarily illustrates a schematic diagram of a high voltage system in an embodiment of the present invention;

[0005] Fig. 2 exemplarily illustrates an exploded partial perspective view of a few systems of a vehicle showing mounting locations of components of the high voltage system onto a vehicle frame;

[0006] Fig. 3 exemplarily illustrates a partial perspective view of a relay mounting bracket mounted on the vehicle frame showing positioning of a relay assembly proximal to an electronic component; [0007] Fig. 4 exemplarily illustrates a perspective view of a relay mounting bracket of the relay assembly, in an embodiment of the present invention;

[0008] Figs. 5A-5B exemplarily illustrates a perspective view and an exploded view of a relay unit, respectively; and

[0009] Fig. 6 exemplarily illustrates a flowchart depicting a logic of controlling operation of each of the relay units of the relay assembly by the electronic component.

DETAILED DESCRIPTION OF THE INVENTION

[00010] One of the protection devices used in the interconnecting wires of the high voltage systems is a contactor switch that is designed for isolating the power supply, that is, the battery from loads in the high-power line. The contactor switch can withstand high amount of current and high arcing voltage spikes, while providing separation of contacts in them. However, the life expectancy of the contactors is reduced due to frequent operation of the contacts in them and opening and closing of the contacts creates electric arc which generates additional heat. Also, the contactors are larger and heavier, making their mounting in the high voltage systems e.g. an electric vehicle with space constraint; difficult in terms of packaging and assembly. If mounted using mounting screws in a desired location in the product, device or a vehicle, manufacturability and serviceability of the product will be difficult.

[00011] In the high voltage system used to power a product or a device, voltage levels of about 400 volts and 800 volts generate sufficient power to run the product. The high voltage systems include multiple batteries, traction motors, controllers, interconnecting wiring, etc. In order to mount the high voltage systems on to a dynamic or mobile product e.g. an electric vehicle to achieve better vehicle handling characteristics, compact packaging of the high voltage systems is needed. However, the compact packaging of the high voltage system in transportation product like a two or three-wheeled electric vehicle may pose a threat to the rider of the vehicle, such as, short circuit, arcing between the terminals of the batteries, overcurrent in electronic components associated with the batteries, causing frequent failures. There exists a need for one or more protection devices with reduced size and weight that can withstand high currents and voltage spikes for isolating the power supply from the loads, in case of a fault, while permitting compact packaging of components in the high voltage systems.

[00012] With the above objective in view, this invention discloses a relay assembly that addressed all problems cited above & other problems of known art.

[00013] Another objective of the present invention is to provide a relay assembly that can be mounted in proximity to an electronic component, for example, a controller in manner to facilitate easy manufacturability, assembly, and serviceability of the high voltage system in applications, such as, a vehicle. Another objective of the present invention is to provide a relay assembly that is lighter in weight, cost-effective, and accessible in installation in applications, such as, a vehicle.

[00014] The relay assembly as per an aspect of the present invention connects a power source to an electronic component in the high voltage system. The relay assembly comprises a first relay unit, a second relay unit positioned perpendicular to the first relay unit, and a relay mounting bracket with at least one locator for positioning the first relay unit and the second relay unit proximal to the electronic component. The first relay unit and the second relay unit comprise a locking pin proximal to a mounting end for positioning the first relay unit and the second relay unit in the locators. The first relay unit and the second relay unit are electrically connected in parallel sharing equal input current. The mounting end of each of the first relay unit and the second relay unit is connected to a positive terminal of the power source and the mounting end of the each of the first relay unit and the second relay unit is connected to the electronic component. [00015] The locking pin is rotated by a predetermined angle, inserted into the locators of the relay mounting bracket, and rotated in a reverse direction by the predetermined angle to lock the first relay unit and the second relay unit in the locators of the relay mounting bracket. The first relay unit and the second relay unit comprise a first cap, a second cap, and a relay enclosed between the first cap and the second cap. The electronic component determines occurrence of a pre charge in the high voltage system and controls timing of making and breaking of each of the first relay unit and the second relay unit.

[00016] In an embodiment of the present invention, a relay mounting bracket is disclosed. The relay mounting bracket comprises a first surface comprising at least one guide hole for mounting an electronic component and a second surface, perpendicular to the first surface, comprising at least one locator and at least one raised flange for positioning at least one relay unit proximal to the electronic component.

[00017] Summary provided above explains the basic features of the invention and does not limit the scope of the invention. The nature and further characteristic features of the present invention will be made clearer from the following description made with reference to the accompanying drawings.

[00018] Fig. 1 exemplarily illustrates a schematic diagram of a high voltage system 100 in an embodiment of the present invention. The high voltage system 100 includes a power source, for example, a battery 101 that sources power to high voltage loads, such as, a motor 103, and an electronic component, such as, a controller 102. The controller 102 controls the operation of the motor 103. A relay assembly 104 is provided connecting the power source, that is, the battery 101 to the controller 102 in the high voltage system 100. The relay assembly 104 comprises a first relay unit 105, a second relay unit 106, and a relay mounting bracket (not shown in Fig. 1) with locators for positioning the first relay unit 105 and the second relay unit 106 proximal to the controller 102. The first relay unit 105 and the second relay unit 106 separate the battery 101 from the motor 103 and the controller 102.

[00019] As exemplarily illustrated, power supply from the battery 101 is split into two paths and connects to the two identical relay units. 105 and 106 The incoming current from the battery 101 is split equally between the relay units 105 and 106 with the same electrical specification, such as, switching voltage, switching current, carry current, resistance, etc. The first relay unit 105 and the second relay unit 106 are connected in parallel sharing equal input current. Using such relay units 105 and 106 connected in parallel, the relay assembly 104 is capable of catering to the high currents and high voltages of the high voltage systems, such as, 100. The two relay units 105 and 106 carry large currents that a high voltage system 100 is expected to carry. Each of the relay units 105 and 106 includes a relay enclosed within a first cap 505 and a second cap 506 as exemplarily illustrated in Fig. 5. The relay is a 4-pin relay or a 5-pin relay. The pins of the relay pierce through the second cap to form contacts of the relay units. Each relay unit 105 and 106 has coil contacts and switch contacts. In a 4-pin relay unit, there are 2 coil contacts and 2 switch contacts. In the 5-pin relay unit, there are 2 coil contacts and 3 switch contacts. The coil contacts energize the coil of the relay. One of the coil contacts can be connected to power supply and the other coil contact is connected to ground. The switch contacts are connected to the battery 101 and the controller 102.

[00020] The switch contacts of the relay units 105 and 106 are connected to each other, and in turn connected to the controller 102. One of the switch contacts of each of the first relay unit 105 and the second relay unit 106 is connected to a positive terminal of the battery 101 and the other switch contact of each of the first relay unit 105 and the second relay unit 106 is connected to the controller 102. The controller 102 controls the timing of making and breaking of contact between the switch contacts of the relay units 105 and 106 as shown by dashed lines. The power lines to source power to the motor 103 are connected to the controller 102. An inverter (not shown) of the controller 102 converts the DC voltage supplied to the controller 102 from the relay units 105 and 106 to AC voltage and the AC voltage drives the motor 103. The controller 102 regenerates DC power back to the battery 101, in case of regenerative operation of the motor 103. In an embodiment, the controller 102 determines occurrence of a pre-charge in the high voltage system 100 and then, controls timing of making and breaking of contact of the switch contacts of each of the first relay unit 105 and the second relay unit 106. The first relay unit 105 and the second relay unit 106 act as a pair of isolation switches between the power source and the electrical load, such as, battery 101 and the motor 103, in case of occurrence of a fault in the high voltage system 100.

[00021] In an embodiment, the high voltage system 100 constitutes a propulsion system of a vehicle. In an embodiment, the vehicle is an electric vehicle or a hybrid electric vehicle. In an embodiment, the vehicle may be a saddle type vehicle. In the electric vehicle, one or more power sources, such as, batteries 101 supply voltage and current to high power consuming loads and to one or more electronic components, such as, controllers. A high-power consuming load is, for example, a traction motor that draws about 30V AC from the batteries. One of the controllers, for example, a motor control unit, controls the operation of the traction motor. The controller is thus connected between the batteries and the traction motor. The interconnecting wires between the batteries, the controller, and the traction motor form a part of a high voltage wiring harness running along the length of the vehicle. The present subject matter, in this embodiment, discloses a relay assembly positioned between the batteries, such as, 101 and the controller 102 to isolate the controller 102 and subsequently the traction motor, such as, the motor 103 from the batteries 101, in case of occurrence of a fault. The high voltage wiring harness and the components such as 101, 102, and 103 connected by the high voltage wiring harness constitutes the high voltage system 100.

[00022] Fig. 2 exemplarily illustrates an exploded partial perspective view of a few systems of a vehicle 200 showing mounting locations of the components such as 102, 105, and 106 of the high voltage systems onto a vehicle frame 201. As exemplarily illustrated, a wiring harness 203 of the vehicle 200 catering to high voltage loads and low voltage loads extends from the head pipe of the vehicle 200 towards the tail lamp of the vehicle 200 along the length of the vehicle 200. The part of the wiring harness 203 that caters to the high voltage loads constitutes the interconnecting wires of the high voltage system 100 of the vehicle 200. The relay units 105 and 106 of the relay assembly 104, shown in Fig. 1, form a part of the high voltage system 100. The relay units 105 and 106 are connected between the battery 101 and the controller 102. Multiple brackets 202 and 204 are provided to mount the batteries 101 and the relay units 105 and 106 are mounted onto the vehicle frame 201. Such mounting brackets are centrally located to maintain the center of gravity of the vehicle 200. The traction motor as per an embodiment may be mounted onto the rear wheel of the vehicle 200. In an embodiment, the relay mounting bracket 204 is centrally located in the vehicle 200 and mounted over the battery mounting bracket 202. The relay units 105 and 106 are positioned in the relay mounting bracket 204. The relay assembly 104 is located proximal to the controller 102. In an embodiment, the controller 102 may be positioned in a separate mounting bracket. As exemplarily illustrated, the controller 102 may be mounted on the same relay mounting bracket 204 as the mounting brackets used for mounting relay units 105 and 106. The relay units 105 and 106 are positioned in locators (not shown) of the relay mounting bracket 204, as will be described in Fig. 4. The controller 102 is also mounted to a vertical planar surface of the relay mounting bracket 204. The relay units 105 and 106 are in close proximity of the controller 102. The relay units 105 and 106 are assembled along with the high voltage wiring harness 203 of the high voltage system 100.

[00023] Fig. 3 exemplarily illustrates a partial perspective view of a relay mounting bracket 204 mounted on the vehicle frame 201, showing positioning of the relay assembly 104 proximal to the controller 102. The first relay unit 105 and the second relay unit 106 are positioned perpendicular to each other. That is, the major length dimensions of the two relay units 105 and 106 are substantially orthogonally disposed with respect to each other. At a mounting end of the relay units 105 and 106, the coil contacts and the switch contacts are located. The mounting end may be a top end or a bottom end of the relay units 105 and 106. As exemplarily illustrated, in an embodiment, the mounting end is the bottom end of the relay units 105 and 106. The bottom end is one end surface of each of the relay units 105 and 106 which is orthogonal to the major length dimension of the relay units 105 and 106 respectively. A power line 301 originating from a positive terminal of the battery 101 is split into two lines 302a and 303a and fed at the mounting end of the first relay unit 105 and the second relay unit 106. The power lines 302a and 303a are connected to a coil contact and a switch contact of each of the first relay unit 105 and the second relay unit 106. That is, the power line 302a is connected to a coil contact and a switch contact of the first relay unit 105. The power line 303a is connected to a coil contact and a switch contact of the second relay unit 106. Another power line 302b and 303b originating from the mounting end of the first relay unit 105 and the second relay unit 106 respectively is joined together into a power line 304 and connected to a positive terminal 305 of the controller 102.

[00024] A power line 306 originating from a negative terminal of the battery 101 is directly connected to the negative terminal 307 of the controller 102. The signal wires for controlling the operation of the first relay unit 105 and the second relay unit 106 are output from the controller 102. The power lines 302b and the 303b to the controller 102 are bundled together using a hole clip 308. The signal lines (not shown) are also bundled together using another hole clip (not shown). The signal lines and the power lines 309 are connected to the high voltage wiring harness 203 of the vehicle 200 using components such as couplers 310. In an embodiment, an additional controller in communication with the controller 102 provides the signal to control the first relay unit 105 and the second relay unit 106.

[00025] Fig. 4 exemplarily illustrates a perspective view of a relay mounting bracket 204 of the relay assembly 104, in an embodiment of the present invention. As exemplarily illustrated, the relay mounting bracket 204 has a first planar surface 401 with guide holes 409 for mounting the controller 102 and an extension portion 406 with guide holes 406a for mounting the interconnecting wire connected to the traction motor, such as, 103. Further, the relay mounting bracket 204 has a second surface 402 with locators 404 for positioning the first relay unit 105 and the second relay unit 106.

[00026] The controller 102 is fastened to the first planar surface 401 with fasteners inserted through the guide holes 409. The second surface 402 has raised flanges 403 and 408 with a locator 405 each for each relay unit 105 and 106 at predetermined locations. Apart from the locators 405, the raised flanges 403 and 408 have guide holes 403a for mounting a protective device, such as, a fuse for the protection of the controller 102. A raised flange 403 for positioning the first relay unit 105 is perpendicular to a raised flange 408 for positioning the second relay unit 106. The locators 404 on the second surface 402 are depressions with a predetermined depth corresponding to the contour of the mounting end of the first relay unit 105 and the second relay unit 106. The second surface 402 is mounted to the vehicle frame 201 using fasteners engaging with an extension member 407.

[00027] The locators 405 on the raised flanges 403 and 408 receive a locking pin of the first relay unit 105 and the second relay unit 106 respectively. The locators 404 and 405 on the second surface 402 and the raised flanges 403 may be circular, rectangular, square, etc., in shape. Correspondingly, the shape of the mounting end of the first relay unit 105 and the second relay unit 106 and the locking pin of the relay units 105 and 106 are circular, rectangular, square, etc. The dimensions of the locators 404 on the second surface 402, such as, length, width, diameter, etc., are corresponding to the dimensions of the mounting end of the first relay unit 105 and the second relay unit 106. The placing of the first relay unit 105 and the second relay unit 106 at substantially 90 degrees to each other results in compact assembly of the relay units 105 and 106 in the vehicle 200. The mounting of the relay assembly 104 above the battery mounting bracket 202 utilizes space efficiently in the vehicle 200 and reduces the length of interconnecting wires running between the battery 101, the relay units 105 and 106, and the controller 102. The fastening of the relay mounting bracket 204 using fasteners is a sturdy mounting and is not susceptible to failure due to vibrations.

[00028] Figs. 5A-5B exemplarily illustrates a perspective view and an exploded perspective view of a relay unit, for example, a first relay unit 105 respectively. The first relay unit 105 comprises a locking pin 501 extending from a side surface 502 proximal to the mounting end 503. The locking pin 501 is a protrusion that engages with the locator 405. To place the first relay unit 105 on the second surface 402 of the relay mounting bracket 204, the mounting end 503 of the first relay unit 105 is positioned in the locator 404 of the second surface 402. Further, the locking pin 501 engages with the locator 405 in the raised flange 408. The locking pin 501 is rotated by a predetermined angle, inserted into the locator 405 of the raised flange 408, and rotated in a reverse direction by the same predetermined angle to lock the first relay unit 105.

[00029] The relay unit, for example, the first relay unit 105 is constituted by a first cap 505, a relay 504, and second cap 506 as exemplarily illustrated in Fig. 5B The first cap 505 and the second cap 506 enclose the relay 504. The relay 504 is an electromechanical switch or a solid state based. The first cap 505 and the second cap 506 are fastened together by fastening means, such as, a snap fit or attached by a suitable attachment means. On a first side 507 of the first relay unit 105, the fastening mean is an external locking element inserted between the extensions 508a and 508b from the first cap 505 and the second cap 506. On a second side 508, the fastening mean is a tongue 509 extending from the second cap 506 that locks with the slot 509 in the first cap 505. As exemplarily illustrated, the locking pin 501 is located on the second cap 506 of the first relay unit 105. The first cap 505 is hollow while the second cap 506 is solid. The first cap 505 has a vent for venting of heat generated while making or breaking the contacts of the relay 504. The second cap 506 has internal electrical connections that connect the contacts of the relay 504 to the mounting end 503 of the first relay unit 105. The switch contacts and the coil contacts of the relay 504 end at the mounting end 503 of the first relay unit 105. A power line extends from a switch contact of the relay 504 to the positive terminal of the battery 101 through the mounting end 503 of the first relay unit 105. Another power line extends from another switch contact of the relay 504 to the controller 102 through the mounting end 503 of the first relay unit 105.

[00030] Fig. 6 exemplarily illustrates a flow chart depicting a logic of controlling operation of each of the relay units, such as, 105 and 106 implemented & executed by the controller 102. As exemplarily illustrated, the controller 102 determines if ignition of the vehicle 200 is turned ON at step 601. In case the ignition is turned ON, during power up procedure, the high voltage system 100 of the vehicle 200 may be exposed to high inrush current. This inrush current may cause damage to the electronic components and high voltage loads in the vehicle 200. A pre-charge circuit is provided as a part of the high voltage system 100. The pre-charge circuit limits the magnitude of the in-rush current in the high voltage system 100, during power up procedure. The controller 102, at step 602, determines if the pre-charge circuit is in operation prior to making or breaking the contacts in the relay units 105 and 106. Based on the input from the pre-charge circuit, the controller 102 sends control signals to the relay units 105 and 106 on the signal wires. If pre-charge is performed, the controller 102, at step 604, actuates the relay units 105 and 106 to make a contact. If the controller 102 determines that pre-charge is not performed, the controller 102, at step 603, does not actuate the relay units 105 and 106 to make a contact. The controller 102 waits for pre-charging to happen before actuating the relay units 105 and 106.

[00031] The relay assembly 104 provides a technical advancement in functioning as a protection device in a high voltage system as follows: The relay assembly comprising the two relay units, such as the first relay unit and the second relay unit replaces contactors that are typically used in high voltage systems. The two relay units function in parallel and receive equal currents from the power source. The relay units are lighter in weight and can be both mounted on the relay mounting bracket. The relay units are positioned substantially perpendicular to each other in the relay mounting bracket, allowing compact packaging of relay units in different applications, such as, in a vehicle. The locking pin on the relay unit aids in tight locking and easy positioning of the relay units in the relay mounting bracket. The manhours of manufacturing and assembly are reduced due to the simple mechanism of mounting the relay units to the relay mounting bracket. Also, the structure of the relay mounting bracket allows for the mounting of the controller to it. Thus, the relay units are in close proximity to the controller, thereby resulting in same resistance to the current flowing from the relay units to the controller. In vehicles, mounting of the relay assembly in the centre of the vehicle maintains the center of gravity of the vehicle substantially in the centre of the vehicle and closer to ground. The hole clips in the relay mounting brackets allows neat, clean, and easily accessible routing of the power lines and signal lines in the high voltage system.