DESC:PROTECTION CIRCUIT FOR TRACTION INVERTER
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority from Indian Provisional Patent Application No. 202221056420 filed on 30/09/2022, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
The present disclosure generally relates to a powertrain unit of an electric vehicle. The present disclosure particularly relates to a powertrain unit of an electric vehicle with a primary protection unit.
BACKGROUND
Recently, there has been a rapid development in electric vehicles because of their ability to resolve pollution-related problems and serve as a clean mode of transportation. Generally, electric vehicles include a battery pack, power pack, and/or combination of electric cells for storing electricity required for the propulsion of the vehicles. The electrical power stored in the battery pack of the electric vehicle is supplied to the traction motor for moving the electric vehicle. The traction inverter converts the power stored in the battery pack to supply to the traction motor.
At present, the powertrain includes a protection circuit that serves to allow the forward flow of current from a battery pack to a motor of the vehicle when the electrical vehicle is working in a driving mode such that the working/operation of the motor is not affected due to flow of the forward current. The driving mode corresponds to a mode in which a vehicle is driven either manually or automatically. Similarly, a separate circuit is used to allow the flow of regenerative current from the motor to the battery pack when the electrical vehicle is working in a regenerative mode such that the working/operation of the battery pack is not affected due to the flow of the regenerative current (i.e. reverse current).
In regenerative braking, the back emf of the motor is greater than the supply voltage, which reverses the direction of the motor armature current. The motor now begins to operate as a generator and the energy generated is supplied to the source. However, when high back EMF is generated in the motor during the regenerative braking, the protection circuit and the regenerative circuit are unable to protect the battery pack from high currents generated due spike of the high back EMF.
Thus, there exists a need for a system that is capable of protecting the battery pack from the high current generated due to the spike of the back EMF during the regenerative braking and overcomes one or more problems associated as set forth above.
SUMMARY
An object of the present disclosure is to provide a powertrain unit of an electric vehicle with a primary protection unit.
Another object of the present disclosure is to provide a primary protection unit for a powertrain unit of an electric vehicle.
In accordance with an embodiment of the present disclosure, there is provided a powertrain unit of an electric vehicle. The powertrain unit comprises a motor drive, a power pack, and a primary protection unit. The motor drive comprises a motor, an inverter and a DC link capacitor. The primary protection unit is configured to allow a forward flow of current in a driving mode, a reverse flow of current in a regenerative mode and block the reverse flow of current in a fault mode.
The present disclosure provides the powertrain unit of an electric vehicle. The powertrain unit of the electric vehicle, as disclosed in the present disclosure, is advantageous in terms of protecting a traction inverter and the power pack from a high back emf generated during the regenerative braking. Moreover, the powertrain unit, as disclosed by the present disclosure is advantageous in terms of preventing traction inverter failure and power pack failure by controlling excessive current generated during the regenerative mode.
In accordance with another embodiment of the present disclosure, there is provided a primary protection unit for a powertrain unit of an electric vehicle. The primary protection unit comprises a MOSFET configured to allow a forward flow of current in a driving mode and a reverse flow of current in a regenerative mode, a resistor and a switch connected in series configured to allow the reverse flow of current in the regenerative mode, and a capacitor and a diode connected in series configured to absorb a back emf spike in the fault mode.
Additional aspects, advantages, features, and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments constructed in conjunction with the appended claims that follow.
It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
Figure 1 illustrates a block diagram of a powertrain unit of an electric vehicle, in accordance with an aspect of the present disclosure.
Figure 2 illustrates a circuit diagram of a powertrain unit of an electric vehicle, in accordance with an embodiment of the present disclosure.
In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
DETAILED DESCRIPTION
The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.
The description set forth below in connection with the appended drawings is intended as a description of certain embodiments of powertrain unit of an electric vehicle and is not intended to represent the only forms that may be developed or utilized. The description sets forth the various structures and/or functions in connection with the illustrated embodiments; however, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
The terms “comprise”, “comprises”, “comprising”, “include(s)”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, or system that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or system. In other words, one or more elements in a system or apparatus preceded by “comprises... a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings which are shown by way of illustration-specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
The present disclosure will be described herein below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the description with unnecessary detail.
As used herein, the terms ‘electric vehicle’, ‘EV’, and ‘EVs’ are used interchangeably and refer to any vehicle having stored electrical energy, including the vehicle capable of being charged from an external electrical power source. This may include vehicles having batteries that are exclusively charged from an external power source, as well as hybrid vehicles which may include batteries capable of being at least partially recharged via an external power source. Additionally, it is to be understood that the ‘electric vehicle’ as used herein includes electric two-wheelers, electric three-wheelers, electric four-wheelers, electric pickup trucks, electric trucks, and so forth.
As used herein, the terms “power source” “battery pack”, “battery”, and “power pack” are used interchangeably and refer to multiple individual battery cells connected to provide a higher combined voltage or capacity than what a single battery can offer. The power pack is designed to store electrical energy and supply it as needed to various devices or systems. Power packs, as referred herein may be used for various purposes such as power electric vehicles and other energy storage applications. Furthermore, the power pack may include additional circuitry, such as a battery management system (BMS), to ensure the safe and efficient charging and discharging of the battery cells. The power pack comprises a plurality of cell arrays which in turn comprises a plurality of battery cells.
As used herein, the term “powertrain unit” refers to a system that converts the electrical energy from the power pack into mechanical energy that drives the wheels of the electric vehicle.
As used herein, the term “inverter”, “drive-train unit” and “DTU” are used interchangeably and refer to a component of the powertrain of an electric vehicle that is responsible for converting direct current (DC) from the battery pack of the electric vehicle into alternating current (AC) to power the electric motor that drives the wheels of the electric vehicle. It is to be understood that the traction inverter is utilized in power conversion, motor control, and regenerative braking of the electric vehicle. The traction inverter comprises advanced power electronics to ensure the smooth and efficient operation of the electric vehicle.
As used herein, the terms “traction motor”, “electric motor”, and “motor” are used interchangeably and refer to a motor specifically designed and employed for the purpose of propelling a vehicle, such as an electric vehicle. It is to be understood that the traction motors rely on electric power to generate motion and provide the necessary torque to drive the wheels of the electric vehicle.
As used herein, the term “motor drive” refers to a system that controls the speed and torque of the electric motor. The motor drive does this by converting the high-voltage DC power from the battery to a low-voltage AC power that is suitable for the electric motor. The motor drive also controls the amount of current that flows to the motor, which determines the motor's speed and torque.
As used herein, the term “gate drivers” refers to electronic components responsible for controlling the switching of Metal Oxide Semiconductor Field Effect Transistor (MOSFET) which forms switches in the traction inverter. It is to be understood that the gate drivers convert the control signal into precise voltage and current pulses required to turn the power electronics switches on and off rapidly. These switches control the flow of electrical current to the electric motor, ultimately determining its speed, torque, and direction of rotation.
As used herein, the term “MOSFET” refers to the Metal-Oxide-Semiconductor Field-Effect Transistor. It is a type of transistor that uses an electric field to control the flow of current through the device. MOSFETs have three terminals: source, gate, and drain. The source and drain terminals are connected to the circuit that the MOSFET is controlling, while the gate terminal is used to control the flow of current through the device. When a voltage is applied to the gate terminal, it creates an electric field that attracts or repels charge carriers in the semiconductor material. This electric field can be used to create a conductive channel between the source and drain terminals, which allows current to flow through the device.
As used herein, the term “forward flow” of current refers to the flow of current from the power pack to the traction motor. This current causes the traction motor to rotate its rotor, which in turn drives the wheels of the electric vehicle.
As used herein, the term “reverse flow” of current refers to the flow of current from the traction motor to the power pack. This current causes the power pack to recharge and extend the range of the electric vehicle.
As used herein, the term “primary protection unit” refers to a safety circuit that protects the electrical and electronic components of the electric vehicle from different forms of electrical damages such as overcharging, overcurrent, overvoltage and so forth.
As used herein, the terms ‘microcontroller’ and ‘processor’ are used interchangeably and refer to a computational element that is operable to respond to and process instructions that control the system. Optionally, the microcontroller may comprise a complex instruction set computing (CISC) microprocessor, a reduced instruction set (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a digital signal processor, or any other type of processing unit or microcontroller. Furthermore, the term “microcontroller” may refer to one or more individual processors, processing devices, and various elements associated with a processing device that may be shared by other processing devices. Furthermore, the microcontroller may be designed to handle real-time tasks with high performance and low power consumption. Furthermore, the microcontroller may comprise custom and/or proprietary processors.
As used herein, the terms “DC link capacitor”, “DC bus capacitor”, and “capacitor” are used interchangeably and refer to a capacitor that is used to smooth out the fluctuating DC voltage between the power pack and the inverter. The DC link capacitor functions to smooth out the power between the two components, stabilize the DC bus voltage, and act as energy storage for transient loads.
As used herein, the term “gate drivers” refers to electronic components responsible for controlling the switching of switches including Metal Oxide Semiconductor Field Effect Transistors (MOSFET), Insulated Gate Bipolar Transistors (IGBT) that may be used as switches. It is to be understood that the gate drivers convert the control signal into precise voltage and current pulses required to turn the power electronics switches on and off rapidly.
As used herein, the term “switch” and “plurality of switch” are used interchangeably and refers to an electronic or mechanical device that controls the flow of electrical current.
As used herein, the term ‘communicably coupled’ refers to a bi-directional connection between the various components of the system. The bi-directional connection between the various components of the system enables the exchange of data between two or more components of the system. Similarly, the bi-directional connection between the system and other elements/modules enables the exchange of data between the system and the other elements/modules.
Figure 1, in accordance with an embodiment, describes a powertrain unit 100 of an electric vehicle. The powertrain unit 100 comprises a motor drive 102, a power pack 104, and a primary protection unit 106. The motor drive 102 comprises a motor 102a, an inverter 102b and a DC link capacitor 102c. The primary protection unit 106 is configured to allow a forward flow of current in a driving mode, a reverse flow of current in a regenerative mode and block the reverse flow of current in a fault mode.
The powertrain unit 100 of an electric vehicle is disclosed. The powertrain unit 100 of the electric vehicle, as disclosed in the present disclosure, is advantageous in terms of protecting the inverter 102b and the power pack 104 from a high back emf generated during the regenerative braking. Moreover, the powertrain unit 100, as disclosed by the present disclosure, is advantageous in terms of preventing failure of the inverter 102b and failure of the power pack 104 by controlling excessive current generated during the regenerative mode. Furthermore, the powertrain unit 100, as disclosed by the present disclosure, is advantageous in terms of preventing failure of the inverter 102b and failure of the power pack 104 by controlling excessive voltage generated during the regenerative mode. Moreover, the powertrain unit 100, as disclosed by the present disclosure, is advantageous in terms of preventing failure of the inverter 102b and failure of the power pack 104 by preventing excessive heat generation during the regenerative mode.
In an embodiment, the driving mode corresponds to normal operating condition of the electric vehicle in which power is delivered from the power pack 104 to the motor 102a. It is to be understood that the driving mode may comprise different dynamics and levels of power delivery from the power pack 104 to the motor 102a. In an example, the driving mode may comprise economy mode, city mode, sport mode, and so forth with different levels of power delivery from the power pack 104 to the motor 102a.
In an embodiment, the regenerative mode corresponds to regenerative braking condition of the electric vehicle in which power is delivered from the motor 102a to the power pack 104. It is to be understood that the power generated at the motor 102a in the regenerative mode corresponds to speed of the motor 102a. Beneficially, the power is delivered from the motor 102a to the power pack 104 recharges the power pack 104 extending the range of the electric vehicle.
In an embodiment, the fault mode corresponds to abnormal condition when a back emf spike capable of damaging the motor drive 102 is generated at the motor 102a. It is to be understood that in the fault mode, the back emf generated at the motor 102a is high enough to damage the components of the inverter, power pack 104 and the DC link capacitor 102c.
In an embodiment, the primary protection unit 106 comprises a MOSFET G configured to allow the forward flow of current through a body diode. It is to be understood that in the normal operating condition the forward flow of current is maintained from the body diode of the MOSFET G maintaining a regular supply of power from the power pack 104 to the motor 102a.
In an embodiment, the MOSFET G is configured to allow reverse flow of current between drain and source. It is to be understood that the MOSFET G does not allow the reverse flow of current between drain to source enabling supply of power from the motor 102a to the power pack 104. A gate driver controls gate of the MOSFET G to enable reverse flow of current between drain and source to allow flow of power from the motor 102a to the power pack 104.
In an embodiment, the MOSFET G blocks the reverse flow of current in the fault mode. It is to be understood that the gate driver opens the gate of the MOSFET G to disable reverse flow of current between drain and source blocking the reverse flow of current in the fault mode.
In an embodiment, the primary protection unit 106 comprises a resistor R and a switch S connected in series, and wherein the switch S is configured to close during the regenerative mode to allow the reverse flow of current through the resistor R along with the MOSFET G connected in parallel. It is to be understood that when the electric vehicle is in regenerative mode, the MOSFET G allows the reverse flow of current from the motor 102a to the power pack 104. Along with the MOSFET G, the switch S is controlled to allow the reverse flow of current through the resistor R along with the MOSFET G connected in parallel. Beneficially, the resistor R would reduce the current reaching the power pack 104 to prevent any potential damage.
In an embodiment, the primary protection unit 106 comprises a capacitor C and a diode D connected in series, and wherein the capacitor C is configured to absorb the back emf spike in the fault mode. Beneficially, the capacitor C absorbs the back emf spike to protect the inverter 102b, the power pack 104 and the DC link capacitor 102c from any potential damage.
In an embodiment, the powertrain unit 100 comprises a microcontroller. In a specific embodiment, the microcontroller is configured to control components of the primary protection unit 106. It is to be understood that the microcontroller is communicably coupled to the components of the primary protection unit 106. In another specific embodiment, the microcontroller is configured to control the gate driver of the MOSFET G to allow the reverse flow of current in the regenerative mode and block the flow of current in the fault mode. In yet another specific embodiment, the microcontroller is configured to control the switch S to allow the reverse flow of current through the resistor R during the regenerative mode.
Figure 2, in accordance with an embodiment, describes a circuit diagram of a powertrain unit 100 of an electric vehicle. The powertrain unit 100 comprises a motor drive 102, a power pack 104, and a primary protection unit 106. The motor drive 102 comprises a motor 102a, an inverter 102b and a DC link capacitor 102c. The primary protection unit 106 is configured to allow a forward flow of current in a driving mode, a reverse flow of current in a regenerative mode and block the reverse flow of current in a fault mode. Furthermore, the driving mode corresponds to normal operating condition of the electric vehicle in which power is delivered from the power pack 104 to the motor 102a. Furthermore, the regenerative mode corresponds to regenerative braking condition of the electric vehicle in which power is delivered from the motor 102a to the power pack 104. Furthermore, the fault mode corresponds to abnormal condition when a back emf spike capable of damaging the motor drive 102 is generated at the motor 102a. Furthermore, the primary protection unit 106 comprises a MOSFET G configured to allow the forward flow of current through a body diode. Furthermore, the MOSFET G is configured to allow reverse flow of current between drain and source. Furthermore, the MOSFET G blocks the reverse flow of current in the fault mode. Furthermore, the primary protection unit 106 comprises a resistor R and a switch S connected in series, and wherein the switch S is configured to close during the regenerative mode to allow the reverse flow of current through the resistor R along with the MOSFET G connected in parallel. Furthermore, the primary protection unit 106 comprises a capacitor C and a diode D connected in series, and wherein the capacitor C is configured to absorb the back emf spike in the fault mode.
In an exemplary embodiment, when the electric vehicle is operating in the driving mode, the power is delivered from the power pack 104 to the motor 102a. When the user of the electric vehicle starts to decelerate performing regenerative braking, the microcontroller detects the same and instructs the gate driver to close MOSFET G allowing reverse flow of current from the motor 102a to the power pack 104. The microcontroller also closes the switch S to allow the reverse flow of current through the resistor R along with the MOSFET G connected in parallel. If the back emf generated in the regenerative mode is higher than a predefined threshold, the microcontroller would switch from the regenerative mode to the fault mode and opens the MOSFET G to restrict the flow of power from the motor 102a to the power pack 104.
In accordance with another embodiment, there is described a primary protection unit 106 for a powertrain unit 100 of an electric vehicle. The primary protection unit 106 comprises a MOSFET G configured to allow a forward flow of current in a driving mode and a reverse flow of current in a regenerative mode, a resistor R and a switch S connected in series configured to allow the reverse flow of current in the regenerative mode, and a capacitor C and a diode D connected in series configured to absorb a back emf spike in the fault mode.
In the description of the present invention, it is also to be noted that, unless otherwise explicitly specified or limited, the terms “disposed,” “mounted,” and “connected” are to be construed broadly, and may for example be fixedly connected, detachably connected, or integrally connected, either mechanically or electrically. They may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Modifications to embodiments and combinations of different embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating”, “have”, and “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural where appropriate.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the present disclosure, the drawings, and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.
,CLAIMS:WE CLAIM:
1. A powertrain unit (100) of an electric vehicle, the powertrain unit (100) comprises:
- a motor drive (102) comprising a motor (102a), an inverter (102b) and a DC link capacitor (102c);
- a power pack (104); and
- a primary protection unit (106);
wherein the primary protection unit (106) is configured to allow a forward flow of current in a driving mode, a reverse flow of current in a regenerative mode and block the reverse flow of current in a fault mode.
2. The powertrain unit (100) as claimed in claim 1, wherein the driving mode corresponds to normal operating condition of the electric vehicle in which power is delivered from the power pack (104) to the motor (102a).
3. The powertrain unit (100) as claimed in claim 1, wherein the regenerative mode corresponds to regenerative braking condition of the electric vehicle in which power is delivered from the motor (102a) to the power pack (104).
4. The powertrain unit (100) as claimed in claim 1, wherein the fault mode corresponds to abnormal condition when a back emf spike capable of damaging the motor drive (102) is generated at the motor (102a).
5. The powertrain unit (100) as claimed in claim 1, wherein the primary protection unit (106) comprises a MOSFET (G) configured to allow the forward flow of current through a body diode.
6. The powertrain unit (100) as claimed in claim 5, wherein the MOSFET (G) is configured to allow reverse flow of current between drain and source.
7. The powertrain unit (100) as claimed in claim 5, wherein the MOSFET (G) blocks the reverse flow of current in the fault mode.
8. The powertrain unit (100) as claimed in claim 1, wherein the primary protection unit (106) comprises a resistor (R) and a switch (S) connected in series, and wherein the switch (S) is configured to close during the regenerative mode to allow the reverse flow of current through the resistor (R) along with the MOSFET (G) connected in parallel.
9. The powertrain unit (100) as claimed in claim 1, wherein the primary protection unit (106) comprises a capacitor (C) and a diode (D) connected in series, and wherein the capacitor (C) is configured to absorb the back emf spike in the fault mode.
10. A primary protection unit (106) for a powertrain unit (100) of an electric vehicle, the primary protection unit (106) comprises:
- a MOSFET (G) configured to allow a forward flow of current in a driving mode and a reverse flow of current in a regenerative mode;
- a resistor (R) and a switch (S) connected in series configured to allow the reverse flow of current in the regenerative mode; and
- a capacitor (C) and a diode (D) connected in series configured to absorb a back emf spike in the fault mode.