DESC:ARRANGEMENT FOR PREVENTING SHOOT-THROUGH CONDITIONS IN TRACTION INVERTERS
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority from Indian Provisional Patent Application No. 202221044121 filed on 02/08/2022, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
The present disclosure generally relates to an arrangement for preventing MOSFET damage in traction inverters. Particularly, the present disclosure relates to an arrangement for preventing shoot-through conditions in a traction inverter. Furthermore, the present disclosure relates to a system for preventing shoot-through conditions in a traction inverter. Furthermore, the present disclosure relates to a method for preventing shoot-through conditions in a traction inverter.
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. A traction inverter is utilized to convert the energy stored in the battery pack into a suitable form for supplying to the traction motor. Generally, the DC power stored in the battery pack is converted into AC power using a traction inverter.
Generally, the traction inverter comprises a DC link capacitor and phase inverter legs. The phase inverter legs of the traction inverter convert the DC power into AC power. Conventionally, each phase inverter leg comprises a pair of MOSFETs acting as switches where the individual MOSFETs of the pair switch alternatively to convert the DC power into AC power. It is required that the individual MOSFETs of the phase inverter leg switch precisely maintaining only one switch in a closed position allowing flow of current at any instant of time. In the conventional phase inverters, a fault can occur causing both the MOSFETs of the phase inverter leg to close simultaneously, leading to a short circuit which causes permanent damage to the phase inverter leg. Such simultaneous opening of the adjacent MOSFETs in the phase inverter legs is called a shoot-through condition. The shoot-through condition may occur due to multiple reasons such as Gate driver failure, faulty operation instructions, faulty snubber circuit, and so forth.
In conventional arrangements, the battery management systems are designed to disconnect from the traction inverter in case of any short circuit. However, such disconnection of the battery power via the battery management system does not prevent the shoot-through condition but rather prevents further damage to the components of the powertrain after the MOSFETs of the phase inverter legs are damaged. Furthermore, conventional traction inverters use dead band control to prevent shoot-through conditions. The dead band control introduces a small delay between the turn-on of the two adjacent MOSFETs ensuring the switches cannot be turned on simultaneously. However, the dead band control reduces the efficiency of the traction inverter, increases the switching losses, and causes a delay in the response of the traction inverter. Furthermore, desaturation protection is also used in combination with the dead band control to prevent shoot-through conditions. However, the desaturation protection reduces the efficiency of the inverter as the switches are turned off prematurely. Thus, such shoot-through prevention methodologies are not feasible for high-frequency switching applications. Moreover, any of the available methods does not disconnect the DC link capacitor from the phase inverter legs which may damage the MOSFETs as the high amount of electrical energy stored in the DC link capacitor remains connected with the phase inverter legs of the traction inverter.
Therefore, there exists a need for a mechanism that prevents shoot-through conditions in the phase inverter legs of the traction inverter and overcomes the one or more problems associated as set forth above.
SUMMARY
An object of the present disclosure is to provide an arrangement for preventing shoot-through condition in a traction inverter.
Another object of the present disclosure is to provide a system for preventing shoot-through condition in a traction inverter.
Yet another object of the present disclosure is to provide a method of preventing shoot-through condition in a traction inverter.
In accordance with the first aspect of the present disclosure, there is provided an arrangement for preventing shoot-through condition in a traction inverter. The arrangement comprises a power source, the traction inverter, a microcontroller, and a traction motor. The traction inverter comprises a DC link capacitor bank, a high frequency disconnect switch, and a plurality of phase inverter legs. The microcontroller is configured to control functioning of the traction inverter. The high frequency disconnect switch is installed between the DC link capacitor bank and the plurality of phase inverter legs. The high frequency disconnect switch is configured to disconnect the plurality of phase inverter legs from the DC link capacitor bank to prevent shoot-through condition.
The present disclosure provides an arrangement that beneficially prevents shoot-through condition in a traction inverter. The present disclosure provides a novel combination of the microcontroller and the high frequency disconnect switch that prevents the shoot-through condition by disconnecting the DC link capacitor from the plurality of phase inverter legs. Beneficially, the microcontroller of the arrangement, as disclosed in the present disclosure, continuously monitors the plurality of phase inverter legs and immediately disconnects the phase inverter leg from the DC link capacitor if a condition leading to shoot-through is detected by the microcontroller. Beneficially, the arrangement for preventing the shoot-through condition of the present disclosure is suitable for operating in high-frequency switching applications such as high-speed electric vehicles. More beneficially, the present arrangement for preventing shoot-through condition does not reduce the efficiency of the traction inverter. More beneficially, the present arrangement for preventing shoot-through condition does not create any switching losses in the traction inverter. More beneficially, the present arrangement for preventing the shoot-through condition is highly efficient in terms of response time resulting in faster switching to prevent the shoot-through condition in the traction inverter. Beneficially, the present arrangement for preventing shoot-through condition simultaneously disconnects the DC link capacitor bank and power source ensuring that no power is supplied to the plurality of phase inverter legs preventing the shoot-through condition and protecting switches of the plurality of phase inverter legs from any damage. Beneficially, the present arrangement is effective in protecting the switches of the plurality of phase inverter legs from shoot-through condition about to happen due to any cause. In other words, the present arrangement is effective in preventing shoot-through condition occurring due to any fault in the traction inverter or other associated components.
In accordance with the second aspect of the present disclosure, there is provided a system for preventing shoot-through condition in a traction inverter. The system comprises a high frequency disconnect switch installed in the traction inverter and a microcontroller communicably coupled to the traction inverter. The microcontroller is configured to continuously monitor a voltage between drain to source of a plurality of switches of the traction inverter, continuously monitor a voltage between gate to source of the plurality of switches of the traction inverter, detect if the voltage between drain to source falls below a predefined threshold when the voltage between gate to source is zero, and instruct the high frequency disconnect switch to open in response to the detected condition.
In accordance with the third aspect of the present disclosure, there is provided a method of preventing shoot-through condition in a traction inverter. The method comprises continuously monitoring a voltage between drain to source of a plurality of switches of the traction inverter, continuously monitoring a voltage between gate to source of the plurality of switches of the traction inverter, detecting if the voltage between drain to source falls below a predefined threshold when the voltage between gate to source is zero, and instructing a high frequency disconnect switch to open in response to the detected condition.
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:
FIG. 1 illustrates a block diagram of an arrangement for preventing shoot-through condition in a traction inverter, in accordance with an aspect of the present disclosure.
FIG. 2 illustrates a circuit diagram of an arrangement for preventing shoot-through condition in a traction inverter comprising high frequency disconnect switch, in accordance with an embodiment of the present disclosure.
FIG. 3 illustrates a block diagram of a system for preventing shoot-through condition in a traction inverter event, in accordance with an embodiment of the present disclosure.
FIG. 4 illustrates a flow chart of a method for calculating electrical energy consumed by an electric vehicle during a charging event, in accordance with another aspect 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 an arrangement for preventing shoot-through conditions in a traction inverter 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 term “traction 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 “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 battery pack is designed to store electrical energy and supply it as needed to various devices or systems. Battery pack, as referred herein may be used for various purposes such as power electric vehicles and other energy storage applications. Furthermore, the battery 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 battery pack comprises a plurality of cell arrays which in turn comprises a plurality of battery cells.
As used herein, the terms “DC link capacitor bank”, “DC link capacitor”, “DC bus capacitor”, and “capacitor” are used interchangeably and refer to a plurality of capacitors that are used to smooth out the fluctuating DC voltage coming from the battery of the electric vehicle before it is converted into AC voltage to power the electric motor. The DC link capacitor bank functions to smooth out the power between the battery of the electric vehicle and the traction inverter, stabilize the DC bus voltage, and act as energy storage for transient loads.
As used herein, the term “high frequency disconnect switch” refers to a switching circuit that is capable of switching at a very high frequency. It is to be understood that the switching time of the high frequency disconnect switch is less than half the switching time of switches present in the traction inverter. It would be appreciated that the high frequency disconnect switch would beneficially cut off the power supply to the switches present in the traction inverter to prevent shoot-through conditions.
As used herein, the terms “plurality of phase inverter legs”, “phase inverter leg”, “inverter legs”, and “phase legs” are used interchangeably and refer to individual circuit blocks of the traction inverter which are responsible for converting the DC power from the DC link capacitor (or the battery) into three-phase AC power to drive the electric motor. It is to be understood that each circuit block converts DC power into one phase of AC power, thus, based on the phases of the electric motor, the traction inverter comprises a number of phase inverter legs.
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 “shoot-through condition” refers to a situation where both upper and lower switches of a specific phase inverter leg are simultaneously turned on, creating a direct short circuit between the positive and negative voltage rails. It is to be understood that the shoot-through condition permanently damages the switches and malfunctions the traction inverter.
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 “switches” and “plurality of switch” are used interchangeably and refers to power electronics devices that control the flow of electrical current to the electric motor. The switches are responsible for converting the DC voltage from the DC link capacitor or battery into an AC waveform to drive the motor. Beneficially, MOSFETs are used as switches in traction inverter as the MOSFETs have low on-state resistance that helps in reducing power losses and increasing the overall efficiency of the traction inverter.
As used herein, the term “electromagnetic interference filters” refers to specialized components designed to reduce or mitigate the electromagnetic noise generated by the traction inverter's power electronics during operation. It is to be understood that electromagnetic interference filters or EMI filters may comprise conducted electromagnetic interference filters, radiated electromagnetic interference filters, or a combination thereof.
As used herein, the term “snubber circuit” refers to an auxiliary circuit that is designed to protect the power electronics switches from voltage spikes and high-frequency transients that can occur during switching operations. The snubber circuit comprises a resistor, capacitor, diode, or a combination thereof. Beneficially, the snubber circuit is designed to match the characteristics of power electronics switches and the switching frequency of the traction inverter.
As used herein, the term “control module” refers to a software module residing in the microprocessor and executed by the microprocessor to control the high-frequency disconnect switch. It is to be understood that the control module may comprise algorithms and control instructions to control the operation of the high frequency disconnect switch.
As used herein, the term “cooling system” refers to a combination of heat sink and cooling chambers used for cooling down the power electronics components and microcontroller of the traction inverter. The cooling system may comprise a cooling fan, vapor cooling chamber, liquid cooling chamber, or a combination thereof.
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 drive the system. Optionally, the microprocessor may be a micro-controller, a complex instruction set computing (CISC) microprocessor, a reduced instruction set (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, or any other type of processing unit. Furthermore, the term “microprocessor” 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 microprocessor may be designed to handle real-time tasks with high performance and low power consumption. Furthermore, the microprocessor may comprise custom and/or proprietary processors.
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.
As used herein, the terms “plurality of sensors” “sensor arrangement” and “sensors” are used interchangeably and refer to a configuration of sensors in the system and/or arrangement to measure, monitor, or detect specific parameters, conditions, and/or events. The plurality of sensors may comprise current sensors, voltage sensors, hall effect sensors, insulation monitoring sensors, or a combination thereof.
Figure 1, in accordance with an embodiment, describes an arrangement 100 for preventing shoot-through condition in a traction inverter 102, in accordance with an embodiment of the present disclosure. The arrangement 100 comprises a power source 104, the traction inverter 102, a microcontroller 112, and a traction motor 114. The traction inverter 102 comprises a DC link capacitor bank 106, a high frequency disconnect switch 108, and a plurality of phase inverter legs 110a, 110b, 110c. The microcontroller 112 is configured to control the functioning of the traction inverter 102. The high frequency disconnect switch 108 is installed between the DC link capacitor bank 106 and the plurality of phase inverter legs 110a, 110b, 110c, and the high frequency disconnect switch 108 is configured to disconnect the plurality of phase inverter legs 110a, 110b, 110c from the DC link capacitor bank 106 to prevent the shoot-through condition.
The present arrangement 100 beneficially prevents shoot-through condition in a traction inverter 102. The arrangement 100 is a novel combination of the microcontroller 112 and the high frequency disconnect switch 108 that prevents the shoot-through condition by disconnecting the DC link capacitor bank 106 from the plurality of phase inverter legs 110a, 110b, 110c. Beneficially, the microcontroller 112 of the arrangement 100, continuously monitors the plurality of phase inverter legs 110a, 110b, 110c and immediately disconnects the phase inverter legs 110a, 110b, 110c from the DC link capacitor bank 106 if a condition leading to shoot-through is detected by the microcontroller 112. Beneficially, the arrangement 100 for preventing shoot-through condition is suitable for operating in high-frequency switching applications such as high-speed electric vehicles. More beneficially, the arrangement 100 for preventing shoot-through condition does not reduce the efficiency of the traction inverter 102. More beneficially, the arrangement 100 for preventing shoot-through condition does not create any switching losses in the traction inverter 102. More beneficially, the arrangement 100 for preventing shoot-through condition is highly efficient in terms of response time resulting in faster switching to prevent the shoot-through condition in the traction inverter 102. Beneficially, the arrangement 100 for preventing shoot-through condition simultaneously disconnects the DC link capacitor bank 106 and the power source 104 ensuring that no power is supplied to the plurality of phase inverter legs 110a, 110b, 110c preventing the shoot-through condition and protecting switches of the plurality of phase inverter legs 110a, 110b, 110c from any damage. Beneficially, the arrangement 100 is effective in protecting the switches of the plurality of phase inverter legs 110a, 110b, 110c from shoot-through condition about to happen due to any cause. In other words, the arrangement 100 is effective in preventing shoot-through condition from occurring due to any fault in the traction inverter 102 or other associated components.
In an embodiment, the power source 104 is a power pack. It is to be understood that the power pack stores DC power and supplies the same to the traction inverter 102. The traction inverter 102 converts the supplied DC power into AC power to drive the traction motor 114. Advantageously, the power pack is a high-density and high-efficiency power pack. Beneficially, the power pack is configured to provide stable power output to the traction inverter 102.
In an embodiment, the DC link capacitor bank 106 of the traction inverter 102 is connected to the power source 104 at one end to minimize voltage ripple between the power source 104 and the traction inverter 102. Beneficially, the DC link capacitor bank 106 absorbs the periodic voltage and/or current spikes between the power source 104 and the traction inverter 102. It would be appreciated that the DC link capacitor bank 106 would absorb the excess amount of voltage and/or current between the power source 104 and the traction inverter 102, and would supply the same to the traction inverter 102 when there is a drop in voltage and/or current between the power source 104 and the traction inverter 102.
In an embodiment, the traction inverter 102 comprises a plurality of gate drivers to control the plurality of phase inverter legs 110a, 110b, 110c. Beneficially, the gate drivers provide high-voltage and high-current signals needed to control the switching of MOSFETs. Beneficially, the gate drivers allow the plurality of phase inverter legs 110a, 110b, 110c to generate the variable voltages and currents needed to control the speed and torque of the traction motor 114.
In an embodiment, the plurality of phase inverter legs 110a, 110b, 110c comprises three phase inverter legs. Beneficially, the three phases of the plurality of phase inverter legs 110a, 110b, 110c generate a three phase AC power output. It is to be understood that the one phase inverter leg generates one phase of AC power, thus, the number of phase inverter legs may vary according to the requirement of phases in power output of the traction inverter 102. In another embodiment, the traction inverter 102 may comprise six phase inverter legs in the plurality of phase inverter legs 110a, 110b, 110c. In yet another embodiment, the traction inverter 102 may comprise phase inverter legs equal to the phases of the traction motor 114.
In an embodiment, each of the phase inverter leg 110a, 110b, 110c comprises a pair of switches, and wherein the pair of switches switch alternatively to convert a DC power received from the power source 104 into an AC power for supplying to the traction motor 114. Beneficially, the pair of switches comprises MOSFETs configured to switch at high frequency for converting the DC power received from the power source 104 into AC power for supplying to the traction motor 114.
In an embodiment, the arrangement 100 comprises a plurality of electromagnetic interference filters configured to filter noise emission from the traction inverter 102. In a specific embodiment, the plurality of electromagnetic interference filters comprises a combination of conducted electromagnetic interference filters and radiated electromagnetic interference filters. Beneficially, the conducted electromagnetic interference filters suppress electromagnetic interference filters that are conducted through electrical conductors. Similarly, the radiated electromagnetic interference filters suppress electromagnetic interference filters that are radiated as radio waves.
In an embodiment, the high frequency disconnect switch 108 comprises a combination of a MOSFET switch and a snubber circuit. Beneficially, the MOSFET switch of the high frequency disconnect switch 108 has a faster switching speed compared to the switches of the plurality of phase inverter legs 110a, 110b, 110c. In a specific embodiment, the switching time of the MOSFET switch of the high frequency disconnect switch 108 has a switching time of less than half of the switching time of the switches of the plurality of phase inverter legs 110a, 110b, 110c. It is to be understood that to prevent the shoot-through condition, the MOSFET switch of the high frequency disconnect switch 108 opens up to disconnect the plurality of phase inverter legs 110a, 110b, 110c from the DC link capacitor bank 106 before the switches of the phase inverter legs 110a, 110b, 110c closes simultaneously, based on the instructions received from the microcontroller 112. Beneficially, the snubber circuit of the high frequency disconnect switch 108 provides additional protection to the switches of the plurality of phase inverter legs 110a, 110b, 110c.
In an embodiment, the microcontroller 112 comprises a control module configured to control the high frequency disconnect switch 108. Beneficially, the control module is configured to act faster than the switches of the plurality of phase inverter legs 110a, 110b, 110c to prevent the shoot-through condition.
In an embodiment, the arrangement 100 comprises a plurality of sensors, and wherein the plurality of sensors are configured to provide sensed information to the microcontroller 112. In a specific embodiment, the plurality of sensors may comprise a combination of voltage sensors, current sensors, hall effect sensors, and so forth. It is to be understood that the plurality of sensors would sense the information related to current and voltage in the phase inverter legs 110a, 110b, 110c and provide the sensed information to the microcontroller 112. Once the sensed information is received by the microcontroller 112, the information is processed by the microcontroller 112 to generate control instructions for the operation and functioning of the traction inverter 102.
In an embodiment, the arrangement 100 comprises power management integrated circuits configured to supply power to the microcontroller 112 and the plurality of sensors. Beneficially, the power management integrated circuits are configured to maintain a calibrated supply of power to the critical components including microcontroller 112 and the plurality of sensors.
In an embodiment, the arrangement 100 comprises a cooling system configured to maintain an optimum temperature of the traction inverter 102 and the microcontroller 112. Beneficially, the cooling system ensures optimal functioning of the electronic components by maintaining the optimum temperature of the traction inverter 102 and the microcontroller 112.
In an exemplary embodiment, the traction inverter 102 is functioning normally driving the traction motor 114 by converting the DC power received from the power source 104 into AC power. The switches of the plurality of phase inverter legs 110a, 110b, 110c are switching alternatively to convert the received DC into AC for supplying to the traction motor 114. The microcontroller 112 would continuously monitor the switches of the plurality of phase inverter legs 110a, 110b, 110c such that when the pair of switches of any phase inverter leg e.g., phase inverter leg 110a, is about to close simultaneously creating shoot-through condition, the microcontroller 112 would sense the same through the plurality of sensors and instruct the high frequency disconnect switch 108 to open, thus, preventing the shoot-through condition. Such prevention of shoot-through condition would protect the switches of the plurality of phase inverter legs 110a, 110b, 110c from any damage.
Figure 2, in accordance with an embodiment, describes a circuit diagram of the traction inverter 102 with high frequency disconnect switch 108. The power source 104 is connected to the traction inverter 102 for supplying DC power. The power supply from the power source 104 is managed by the battery management system which is configured to cut off the power supply to the traction inverter 102 in case of any short-circuit or power supply 104 related faults. The power supplied from the power source 104 reaches the traction inverter 102 through the DC link capacitor bank 106. The DC link capacitor bank 106 minimizes any voltage ripple between the power source 104 and the traction inverter 102. The high frequency disconnect switch 108 is installed between the DC link capacitor bank and the plurality of phase inverter legs 110a, 110b, 110c. The high frequency disconnect switch 108 disconnects the DC link capacitor bank 106 and the plurality of phase inverter legs 110a, 110b, 110c to prevent the shoot-through condition.
Figure 3, in accordance with an embodiment, describes system 300 for preventing shoot-through condition in a traction inverter 302. The system comprises a high frequency disconnect switch 308 installed in the traction inverter 302 and a microcontroller 312 communicably coupled to the traction inverter 302. The microcontroller 312 is configured to continuously monitor a voltage between drain to source of a plurality of switches of the traction inverter 302, continuously monitor a voltage between gate to source of the plurality of switches of the traction inverter 302, detect if the voltage between drain to source falls below a predefined threshold when the voltage between gate to the source is zero, and instruct the high frequency disconnect switch 308 to open in response to the detected condition.
In an embodiment, the system 300 comprises a plurality of sensors, wherein the microcontroller 312 receives the voltage between the drain to the source of the plurality of switches and the voltage between the gate to the source of the plurality of switches from the plurality of sensors. In a specific embodiment, the plurality of sensors may comprise a combination of voltage sensors, current sensors, hall effect sensors, and so forth. It is to be understood that the plurality of sensors would sense the information related to current and voltage in the phase inverter legs and provide the sensed information to the microcontroller 312. Once the sensed information is received by the microcontroller 312, the information is processed by the microcontroller 312 to generate control instructions for the operation and functioning of the traction inverter 302.
In an embodiment, the system 300 is connected to a power source, wherein the power source is a power pack supplying DC power to the system 300. It is to be understood that the power pack stores DC power and supplies the same to the traction inverter 302. The traction inverter 302 converts the supplied DC power into AC power to drive the traction motor. Advantageously, the power pack is a high-density and high-efficiency power pack. Beneficially, the power pack is configured to provide stable power output to the traction inverter 302.
In an embodiment, the system 300 is coupled to a traction motor and configured to supply AC power to the traction motor. Beneficially, the traction motor drives the wheels of electric vehicles.
In an embodiment, the traction inverter 302 comprises a plurality of phase inverter legs, wherein each of the phase inverter leg comprises a pair of switches, and wherein the pair of switches switch alternatively to convert the DC power received from the power source into the AC power for supplying to the traction motor. Beneficially, the pair of switches comprises MOSFETs configured to switch at high frequency for converting the DC power received from the power source into AC power for supplying to the traction motor. In a specific embodiment, the plurality of phase inverter legs comprises three phase inverter legs. Beneficially, the three phases of the plurality of phase inverter legs generate a three phase AC power output. It is to be understood that the one phase inverter leg generates one phase of AC power, thus, the number of phase inverter legs may vary according to the requirement of phases in power output of the traction inverter 302. In another embodiment, the traction inverter 302 may comprise six phase inverter legs in the plurality of phase inverter legs. In yet another embodiment, the traction inverter 302 may comprise phase inverter legs equal to the phases of the traction motor.
In an embodiment, the traction inverter 302 comprises a DC link capacitor bank, wherein the DC link capacitor bank is connected to the power source at one end to minimize voltage ripple between the power source and the traction inverter 302. Beneficially, the DC link capacitor bank absorbs the periodic voltage and/or current spikes between the power source and the traction inverter 302. It would be appreciated that the DC link capacitor bank would absorb the excess amount of voltage and/or current between the power source and the traction inverter 302, and would supply the same to the traction inverter 302 when there is a drop in voltage and/or current between the power source and the traction inverter 302.
In an embodiment, the traction inverter 302 comprises a plurality of gate drivers to control the plurality of phase inverter legs. Beneficially, the gate drivers provide high-voltage and high-current signals needed to control the switching of MOSFETs. Beneficially, the gate drivers allow the plurality of phase inverter legs to generate the variable voltages and currents needed to control the speed and torque of the traction motor.
In an embodiment, the system 300 comprises a plurality of electromagnetic interference filters configured to filter noise emission from the traction inverter 302. In a specific embodiment, the plurality of electromagnetic interference filters comprises a combination of conducted electromagnetic interference filters and radiated electromagnetic interference filters. Beneficially, the conducted electromagnetic interference filters suppress electromagnetic interference filters that are conducted through electrical conductors. Similarly, the radiated electromagnetic interference filters suppress electromagnetic interference filters that are radiated as radio waves.
In an embodiment, the high frequency disconnect switch 308 comprises a combination of MOSFET switch and a snubber circuit. Beneficially, the MOSFET switch of the high frequency disconnect switch 108 has a faster switching speed compared to the switches of the plurality of phase inverter legs 110a, 110b, 110c. In a specific embodiment, the switching time of the MOSFET switch of the high frequency disconnect switch 308 has a switching time of less than half of the switching time of the switches of the plurality of phase inverter legs. It is to be understood that to prevent the shoot-through condition, the MOSFET switch of the high frequency disconnect switch 308 opens up to disconnect the plurality of phase inverter legs from the DC link capacitor bank before the switches of the phase inverter legs close simultaneously, based on the instructions received from the microcontroller 312. Beneficially, the snubber circuit of the high frequency disconnect switch 308 provides additional protection to the switches of the plurality of phase inverter legs.
In an embodiment, the microcontroller 312 comprises a control module configured to control the high frequency disconnect switch 308, wherein the microcontroller 312 instructs the high frequency disconnect switch 308 via the control module. Beneficially, the control module is configured to act faster than the switches of the plurality of phase inverter legs to prevent the shoot-through condition.
In an embodiment, the system 300 comprises power management integrated circuits configured to supply power to the microcontroller 312 and the plurality of sensors. Beneficially, the power management integrated circuits are configured to maintain a calibrated supply of power to the critical components including microcontroller 312 and the plurality of sensors.
In an embodiment, the system 300 comprises a cooling system configured to maintain an optimum temperature of the traction inverter 302 and the microcontroller 312. Beneficially, the cooling system ensures optimal functioning of the electronic components by maintaining the optimum temperature of the traction inverter 302 and the microcontroller 312.
In an embodiment, the high frequency disconnect switch 308 is installed between the DC link capacitor bank and the plurality of phase inverter legs, and wherein the high frequency disconnect switch 308 opens to disconnect the plurality of phase inverter legs from the DC link capacitor bank to prevent shoot-through condition.
It is to be understood that the voltage between the drain to the source of a plurality of switches of the traction inverter 302 would fall below a certain threshold when the switches are about to close resulting in flowing of current through the switch. Similarly, the voltage between gate to source of the plurality of switches of the traction inverter 302 would be tending towards zero when the switch is open. In the normal functioning switch, a voltage is applied between the gate to source to create a current flow path between the drain to source of the switch. Therefore, in an exemplary embodiment, the switches of the plurality of phase inverter legs are switching alternatively to convert the received DC into AC for supplying to the traction motor. The microcontroller 312 would continuously monitor the switches of the plurality of phase inverter legs such that when the pair of switches of any phase inverter leg is about to close simultaneously creating shoot-through condition, the microcontroller 312 would sense the same through the plurality of sensors and instruct the high frequency disconnect switch 308 to open, thus, preventing the shoot-through condition. Specifically, the microcontroller 312 would continuously monitor the voltage between drain to source of the plurality of switches of the traction inverter 302 to track the functioning of the switch. Simultaneously, the microcontroller 312 would continuously monitor a voltage between gate to source of the plurality of switches of the traction inverter 302 to track the control of the switch. If the microcontroller 312 detects that the voltage between the drain to the source falls below a predefined threshold, indicating closing of the switch to pass the current, and the voltage between the gate to the source is zero indicating that the switch has not been instructed by the microcontroller 312 to close normally for performing a normal function, the microcontroller 312 would instruct the high-frequency disconnect switch 308 to open preventing the g shoot-through condition.
Figure 4, describes a method 400 of preventing shoot-through condition in a traction inverter 302. The method 400 starts at step 402 and completes at step 408. At step 402, the method 400 comprises continuously monitoring a voltage between drain to source of a plurality of switches of the traction inverter 302. At step 404, the method 400 comprises continuously monitoring a voltage between gate to source of the plurality of switches of the traction inverter 302. At step 406, the method 400 comprises detecting if the voltage between drain to source falls below a predefined threshold when the voltage between gate to source is zero. At step 408, the method 400 comprises instructing a high frequency disconnect switch 308 to open in response to the detected condition.
In an embodiment, the method 400 comprises receiving the voltage between drain to source of the plurality of switches and the voltage between gate to source of the plurality of switches from a plurality of sensors.
In an embodiment, the method 400 comprises opening the high frequency disconnect switch 308 for disconnecting a plurality of phase inverter legs from a DC link capacitor bank to prevent shoot-through condition.
It would be appreciated that all the explanations and embodiments of the arrangement 100 and system 300 also apply mutatis-mutandis to the method 400.
In another aspect of the present disclosure, there is disclosed a computer program product comprising a non-transitory computer-readable storage medium having computer-readable instructions stored thereon, the computer-readable instructions being executable by a computerized device comprising processing hardware to execute method 400.
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. An arrangement (100) for preventing shoot-through condition in a traction inverter (102), wherein the arrangement (100) comprises:
- a power source (104);
- the traction inverter (102) comprising a DC link capacitor bank (106), a high frequency disconnect switch (108) and a plurality of phase inverter legs (110a, 110b, 110c);
- a microcontroller (112) configured to control functioning of the traction inverter (102); and
- a traction motor (114),
wherein the high frequency disconnect switch (108) is installed between the DC link capacitor bank (106) and the plurality of phase inverter legs (110a, 110b, 110c), and wherein the high frequency disconnect switch (108) is configured to disconnect the plurality of phase inverter legs (110a, 110b, 110c) from the DC link capacitor bank (106) to prevent shoot-through condition.
2. The arrangement (100) as claimed in claim 1, wherein the power source (104) is a power pack.
3. The arrangement (100) as claimed in claims 1 and 2, wherein the DC link capacitor bank (106) of the traction inverter (102) is connected to the power source (104) at one end to minimize voltage ripple between the power source (104) and the traction inverter (102).
4. The arrangement (100) as claimed in claims 1 to 3, wherein the traction inverter (102) comprises a plurality of gate drivers to control the plurality of phase inverter legs (110a, 110b, 110c).
5. The arrangement (100) as claimed in claims 1 to 4, wherein the plurality of phase inverter legs (110a, 110b, 110c) comprises three phase inverter legs.
6. The arrangement (100) as claimed in claims 1 to 5, wherein each of the phase inverter leg (110a, 110b, 110c) comprises a pair of switches, and wherein the pair of switches switch alternatively to convert a DC power received from the power source (104) into an AC power for supplying to the traction motor (114).
7. The arrangement (100) as claimed in claims 1 to 6, wherein the arrangement (100) comprises a plurality of electromagnetic interference filters configured to filter noise emission from the traction inverter (102).
8. The arrangement (100) as claimed in claims 1 to 7, wherein the high frequency disconnect switch (108) comprises a combination of MOSFET switch and a snubber circuit.
9. The arrangement (100) as claimed in claims 1 to 8, wherein the microcontroller (112) comprises a control module configured to control the high frequency disconnect switch (108).
10. The arrangement (100) as claimed in claims 1 to 9, wherein the arrangement (100) comprises a plurality of sensors, and wherein the plurality of sensors are configured to provide sensed information to the microcontroller (112).
11. The arrangement (100) as claimed in claims 1 to 10, wherein the arrangement (100) comprises power management integrated circuits configured to supply power to the microcontroller (112) and the plurality of sensors.
12. The arrangement (100) as claimed in claims 1 to 11, wherein the arrangement (100) comprises a cooling system configured to maintain an optimum temperature of the traction inverter (102) and the microcontroller (112).
13. A system (300) for preventing shoot-through condition in a traction inverter (302), wherein the system comprises:
- a high frequency disconnect switch (308) installed in the traction inverter (302);
- a microcontroller (312) communicably coupled to the traction inverter (302) and configured to:
- continuously monitor a voltage between drain to source of a plurality of switches of the traction inverter (302);
- continuously monitor a voltage between gate to source of the plurality of switches of the traction inverter (302);
- detect if the voltage between drain to source falls below a predefined threshold when the voltage between gate to source is zero; and
- instruct the high frequency disconnect switch (308) to open in response to the detected condition.
14. The system (300) as claimed in claim 13, wherein the system (300) comprises a plurality of sensors, wherein the microcontroller (312) receives the voltage between drain to source of the plurality of switches and the voltage between gate to source of the plurality of switches from the plurality of sensors.
15. The system (300) as claimed in claims 13 and 14, wherein the system (300) is connected to a power source, wherein the power source is a power pack supplying DC power to the system (300).
16. The system (300) as claimed in claims 13 to 15, wherein the system (300) is coupled to a traction motor and configured to supply AC power to the traction motor.
17. The system (300) as claimed in claims 13 to 16, wherein the traction inverter (302) comprises a plurality of phase inverter legs, wherein each of the phase inverter leg comprises a pair of switches, and wherein the pair of switches switch alternatively to convert the DC power received from the power source into the AC power for supplying to the traction motor.
18. The system (300) as claimed in claims 13 to 17, wherein the traction inverter (302) comprises a DC link capacitor bank, wherein the DC link capacitor bank is connected to the power source at one end to minimize voltage ripple between the power source and the traction inverter (302).
19. The system (300) as claimed in claims 13 to 18, wherein the traction inverter (302) comprises a plurality of gate drivers to control the plurality of phase inverter legs.
20. The system (300) as claimed in claims 13 to 19, wherein the system (300) comprises a plurality of electromagnetic interference filters configured to filter noise emission from the traction inverter (302).
21. The system (300) as claimed in claims 13 to 20, wherein the high frequency disconnect switch (308) comprises a combination of MOSFET switch and a snubber circuit.
22. The system (300) as claimed in claims 13 to 21, wherein the microcontroller (312) comprises a control module configured to control the high frequency disconnect switch (308), wherein the microcontroller (312) instructs the high frequency disconnect switch (308) via the control module.
23. The system (300) as claimed in claims 13 to 22, wherein the system (300) comprises power management integrated circuits configured to supply power to the microcontroller (312) and the plurality of sensors.
24. The system (300) as claimed in claims 13 to 23, wherein the system (300) comprises a cooling system configured to maintain an optimum temperature of the traction inverter (302) and the microcontroller (312).
25. The system (300) as claimed in claims 13 to 24, wherein the high frequency disconnect switch (308) is installed between the DC link capacitor bank and the plurality of phase inverter legs, and wherein the high frequency disconnect switch (308) opens to disconnect the plurality of phase inverter legs from the DC link capacitor bank to prevent shoot-through condition.
26. A method (400) of preventing shoot-through condition in a traction inverter (302), comprising:
- continuously monitoring a voltage between drain to source of a plurality of switches of the traction inverter (302);
- continuously monitoring a voltage between gate to source of the plurality of switches of the traction inverter (302);
- detecting if the voltage between drain to source falls below a predefined threshold when the voltage between gate to source is zero; and
- instructing a high frequency disconnect switch (308) to open in response to the detected condition.
27. The method (400) as claimed in claim 26, wherein the method (400) comprises receiving the voltage between drain to source of the plurality of switches and the voltage between gate to source of the plurality of switches from a plurality of sensors.
28. The method (400) as claimed in claims 26 and 27, wherein the method (400) comprises opening the high frequency disconnect switch (308) for disconnecting a plurality of phase inverter legs from a DC link capacitor bank to prevent shoot-through condition.