Claims:1. A method for active discharge of a charged source of an automotive Electronic Control Unit (ECU) comprising a full bridge rectifier electrically coupled with the charged source, and having a first leg with a pair of switches M1 and M2, and a second leg with a pair of switches M3 and M4, wherein the full bridge rectifier is electrically coupled with a power supply through a transformer, said method comprising:
switching, by a control unit operatively coupled with the full bridge rectifier, the switch M2 of the first leg to the ON state and the switch M4 of the second leg to the OFF state, at a fixed duty cycle; and switching the switch M2 of the first leg to the OFF state and the switch M4 of the second leg to the ON state, at a fixed duty cycle; and
switching, by the control unit, the switch M1 of the first leg and the switch M3 of the second leg between the ON state and the OFF state, wherein the switching of the switch M1 and the switch M3 is performed at a fixed frequency during the fixed duty cycle;
wherein during the switching of the switch M1 and the switch M3, overlapping of the ON state of the switch M1 with the ON state of the switch M2, and the OFF state of the switch M3 with the OFF state of the switch M4, creates a short-circuit across the charged source resulting in discharging of the charged source; and
wherein during the switching of the switch M1 and the switch M3, overlapping of the OFF state of the switch M1 with the OFF state of the switch M2, and the ON state of the switch M3 with the ON state of the switch M4, creates a short-circuit across the charged source resulting in discharging of the charged source; and
wherein, the control unit is configured to facilitate supply of electric power stored in the charged source to each of the switches M1 and M2 of the first leg and the switches M3 and M4 of the second leg to enable switching of the pair of switches M1 and M2 of the first leg and the pair of switches M3 and M4 of the second leg between the ON state and the OFF state, leading to gate switching losses that also results in discharging of the charged source.
2. The method as claimed in claim 1, wherein the ECU includes any or a combination of automotive DC-DC converter, Inverter, On Board Charger (OBC), or integrated DCDC-OBC with high voltage safety.
3. The method as claimed in claim 1, wherein a nominal parasitic inductance of the ECU and the duty cycle facilitates to limit a current flow through each of the pair of switches at a predefined value during discharging of the charged source, and wherein the duty cycle is determined based on the nominal parasitic inductance of the ECU and voltage of a DC bus through which the first leg, the second leg, and the charged source are connected to each other.
4. The method as claimed in claim 1, wherein when the switching is performed at a fixed frequency during the fixed duty cycle, a current flow through each of the pair of switches at a predefined level that is within a predefined maximum rated current of each of the pair of switches.
5. The method as claimed in claim 1, wherein the control unit is configured to facilitate switching of the switch M1 of the first leg and the switch M4 of the second leg to the ON state, and the switch M2 of the first leg and the switch M3 of the second leg to the OFF state at a predefined duty cycle during a normal converter operation of the charger.
6. The method as claimed in claim 1, wherein the control unit is configured to facilitate switching of the switch M2 of the first leg and the switch M3 of the second leg to the ON state, and the switch M1 of the first leg and the switch M4 of the second leg to the OFF state at a predefined duty cycle during a normal converter operation of the charger.
7. The method as claimed in claim 1, wherein the ECU is electrically coupled to a high voltage battery through a set of switches S1 and S2, and wherein the control unit is configured to facilitate simultaneous switching of each of the switch S1 and the switch S2.
8. The method as claimed in claim 1, wherein the charged source of the ECU is a Direct Current (DC) Link capacitor.
9. A system for active discharge of a charged source of an automotive ECU charger comprising a full bridge rectifier electrically coupled with the charged source, and having a first leg with a pair of switches M1 and M2, and a second leg with a pair of switches M3 and M4, wherein the full bridge rectifier is electrically coupled with a power supply through a transformer, the system comprising:
a control unit comprising one or more processors, and electrically coupled with the full bridge rectifier, said control unit configured to:
switch the switch M2 of the first leg to the ON state and the switch M4 of the second leg to the OFF state at a fixed cycle; and switch the switch M2 of the first leg to the OFF state and the switch M4 of the second leg to the ON state, at a fixed duty cycle; and
switch the switch M1 of the first leg and the switch M3 of the second leg, between the ON state and the OFF state, wherein the switching of the switch M1 and the switch M3 is performed at a fixed frequency during the fixed duty cycle;
wherein during the switching of the switch M1 and the switch M3, overlapping of the ON state of the switch M1 with the ON state of the switch M2, and the OFF state of the switch M3 with the OFF state of the switch M4, creates a short-circuit across the charged source resulting in discharging of the charged source; and
wherein during the switching of the switch M1 and the switch M3, overlapping of the OFF state of the switch M1 with the OFF state of the switch M2, and the ON state of the switch M3 with the ON state of the witch M4, creates a short-circuit across the charged source resulting in discharging of the charged source; and
wherein, the control unit is configured to facilitate supply of electric power stored in the charged source to each of the switches M1 and M2 of the first leg and the switches M3 and M4 of the second leg to enable switching of the pair of switches M1 and M2 of the first leg and the pair of switches M3 and M4 of the second leg between the ON state and the OFF state, leading to gate switching losses that also results in discharging of the charged source.
, Description:FIELD OF DISCLOSURE
[0001] The present disclosure relates to the field of automotive chargers. More particularly, the present disclosure relates to system and method for discharging a charged source in the automotive chargers for high voltage safety.

BACKGROUND OF THE DISCLOSURE
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] With the development of technology, vehicles are employed with a lot of electrical accessories. However, such vehicles encounters some problems, among which high driving mileage and fast charging technology has become a major challenge in the development of electric vehicles. For implementing fast charging technology in the vehicle, the vehicles are generally employed with power electronic circuits. In the power electronic circuits, charging and discharging of a source are required to be done within the minimum time. In an example, the high voltage (HV) net should be discharged from maximum high voltage (HV) to less than 60V (HV safety limit) within 5s in an event of failure. But OEMs could have stringent requirements than 5s for ex: 1s discharge time based on their vehicle architecture.
[0004] Presently, existing automotive chargers uses discharge resistors or PTC (Positive Temperature Coefficient) thermistor in conjunction with switches for discharging purpose. However, the discharge resistor increases cost and size of the overall system. In addition, the discharge resistor, requires more time for discharging. Further, the use of high voltage (HV) to low voltage (LV) DC-DC converter for discharging the capacitor poses a risk in an event where the LV battery is disconnected, which is a primary trigger for active discharge.
[0005] There is therefore a need in the art for system and method, which overcome above-mentioned and other limitations of existing approaches.
[0006] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0007] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

OBJECTS OF THE INVENTION
[0008] A general object of the present disclosure is to provide method and system for discharging a charged source for high voltage safety without additional components.
[0009] An object of the present disclosure is to provide a cost-effective system that is easy to implement and compact in size.
[00010] An object of the present disclosure is to provide a system that requires a minimal number of components.
[00011] Another object of the present disclosure is to provide method and system that limit temperature rise of the components, thereby eliminating requirements of any additional thermal interfaces.

SUMMARY
[00012] The present disclosure relates to the field of automotive chargers. More particularly, the present disclosure relates to system and method for discharging a charged source in the automotive chargers for high voltage safety.
[00013] An aspect of the present disclosure relates to a method for active discharge of a charged source of an automotive Electronic Control Unit (ECU). The ECU comprises a full bridge rectifier electrically coupled with the charged source, and having a first leg with a pair of switches M1 and M2, and a second leg with a pair of switches M3 and M4. The full bridge rectifier is electrically coupled with a power supply through a transformer. The method comprising: switching, by a control unit operatively coupled with the full bridge rectifier, the switch M2 of the first leg to the ON state and the switch M4 of the second leg to the OFF state, at a fixed duty cycle; and switching the switch M2 of the first leg to the OFF state and the switch M4 of the second leg to the ON state, at a fixed duty cycle; and switching, by the control unit, the switch M1 of the first leg and the switch M3 of the second leg between the ON state and the OFF state, wherein the switching of the switch M1 and the switch M3 is performed at a fixed frequency during the fixed duty cycle. During the switching of the switch M1 and the switch M3, overlapping of the ON state of the switch M1 with the ON state of the switch M2, and the OFF state of the switch M3 with the OFF state of the switch M4, creates a short-circuit across the charged source resulting in discharging of the charged source. During the switching of the switch M1 and the switch M3, overlapping of the OFF state of the switch M1 with the OFF state of the switch M2, and the ON state of the switch M3 with the ON state of the switch M4, creates a short-circuit across the charged source resulting in discharging of the charged source. The control unit is configured to facilitate supply of electric power stored in the charged source to each of the switches M1 and M2 of the first leg and the switches M3 and M4 of the second leg to enable switching of the pair of switches M1 and M2 of the first leg and the pair of switches M3 and M4 of the second leg between the ON state and the OFF state, leading to gate switching losses that also results in discharging of the charged source.
[00014] In an embodiment, the ECU includes any or a combination of automotive DC-DC converter, Inverter, On Board Charger (OBC), or integrated DCDC-OBC with high voltage safety.
[00015] In an embodiment, a nominal parasitic inductance of the ECU and the duty cycle facilitates to limit a current flow through each of the pair of switches at a predefined value during discharging of the charged source, and wherein the duty cycle is determined based on the nominal parasitic inductance of the ECU and voltage of a DC bus through which the first leg, the second leg, and the charged source are connected to each other.
[00016] In an embodiment, when the switching is performed at a fixed frequency during the fixed duty cycle, a current flows through each of the pair of switches at a predefined level that is within a predefined maximum rated current of each of the pair of switches.
[00017] In an embodiment, the control unit is configured to facilitate switching of the switch M1 of the first leg and the switch M4 of the second leg to the ON state, and the switch M2 of the first leg and the switch M3 of the second leg to the OFF state at a predefined duty cycle during a normal converter operation of the charger.
[00018] In an embodiment, the control unit is configured to facilitate switching of the switch M2 of the first leg and the switch M3 of the second leg to the ON state, and the switch M1 of the first leg and the switch M4 of the second leg to the OFF state at a predefined duty cycle during a normal converter operation of the charger.
[00019] In an embodiment, the ECU is electrically coupled to a high voltage battery through a set of switches S1 and S2, and wherein the control unit is configured to facilitate simultaneous switching of each of the switch S1 and the switch S2.
[00020] In an embodiment, the charged source of the ECU is a Direct Current (DC) Link capacitor.
[00021] Another aspect of the present disclosure a system for active discharge of a charged source of an automotive ECU charger. The ECU charger comprises a full bridge rectifier electrically coupled with the charged source, and having a first leg with a pair of switches M1 and M2, and a second leg with a pair of switches M3 and M4, wherein the full bridge rectifier is electrically coupled with a power supply through a transformer. The system comprising: a control unit comprising one or more processors, and electrically coupled with the full bridge rectifier, said control unit configured to: switch the switch M2 of the first leg to the ON state and the switch M4 of the second leg to the OFF state at a fixed cycle; and switch the switch M2 of the first leg to the OFF state and the switch M4 of the second leg to the ON state, at a fixed duty cycle; and switch the switch M1 of the first leg and the switch M3 of the second leg, between the ON state and the OFF state, wherein the switching of the switch M1 and the switch M3 is performed at a fixed frequency during the fixed duty cycle. During the switching of the switch M1 and the switch M3, overlapping of the ON state of the switch M1 with the ON state of the switch M2, and the OFF state of the switch M3 with the OFF state of the switch M4, creates a short-circuit across the charged source resulting in discharging of the charged source. During the switching of the switch M1 and the switch M3, overlapping of the OFF state of the switch M1 with the OFF state of the switch M2, and the ON state of the switch M3 with the ON state of the witch M4, creates a short-circuit across the charged source resulting in discharging of the charged source. The control unit is configured to facilitate supply of electric power stored in the charged source to each of the switches M1 and M2 of the first leg and the switches M3 and M4 of the second leg to enable switching of the pair of switches M1 and M2 of the first leg and the pair of switches M3 and M4 of the second leg between the ON state and the OFF state, leading to gate switching losses that also results in discharging of the charged source.
[00022] Various objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like features.

BRIEF DESCRIPTION OF DRAWINGS
[00023] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The diagrams are for illustration only, which thus is not a limitation of the present disclosure.
[00024] FIG. 1 illustrates an exemplary representation of system for discharging a charged source, in accordance with an embodiment of the present disclosure.
[00025] FIG. 2 illustrates block diagram of switching circuit of the control unit, in accordance with embodiments of the present disclosure.
[00026] FIGs. 3A and 3B illustrate exemplary representations of switching pattern 1 and corresponding current through switches, in accordance with embodiments of present disclosure.
[00027] FIG. 4 illustrates an exemplary representation of switching pattern 2, in accordance with embodiments of present disclosure.
[00028] FIG. 5 illustrates an exemplary representation showing a relation between discharge time vs HV voltage, in accordance with embodiments of present disclosure.

DETAILED DESCRIPTION
[00029] In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.
[00030] Various methods described herein may be practiced by combining one or more machine-readable storage media containing the code according to the present invention with appropriate standard computer hardware to execute the code contained therein. An apparatus for practicing various embodiments of the present invention may involve one or more computers (or one or more processors within a single computer) and storage systems containing or having network access to computer program(s) coded in accordance with various methods described herein, and the method steps of the invention could be accomplished by modules, routines, subroutines, or subparts of a computer program product.
[00031] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[00032] Embodiments of the present invention may be provided as a computer program product, which may include a machine-readable storage medium tangibly embodying thereon instructions, which may be used to program a computer (or other electronic devices) to perform a process. The term “machine-readable storage medium” or “computer-readable storage medium” includes, but is not limited to, fixed (hard) drives, magnetic tape, floppy diskettes, optical disks, compact disc read-only memories (CD-ROMs), and magneto-optical disks, semiconductor memories, such as ROMs, PROMs, random access memories (RAMs), programmable read-only memories (PROMs), erasable PROMs (EPROMs), electrically erasable PROMs (EEPROMs), flash memory, magnetic or optical cards, or other type of media/machine-readable medium suitable for storing electronic instructions (e.g., computer programming code, such as software or firmware).A machine-readable medium may include a non-transitory medium in which data may be stored and that does not include carrier waves and/or transitory electronic signals propagating wirelessly or over wired connections. Examples of a non-transitory medium may include, but are not limited to, a magnetic disk or tape, optical storage media such as compact disk (CD) or digital versatile disk (DVD), flash memory, memory or memory devices. A computer-program product may include code and/or machine-executable instructions that may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment may be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted via any suitable means including memory sharing, message passing, token passing, network transmission, etc.
[00033] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[00034] The present disclosure relates to the field of automotive chargers. More particularly, the present disclosure relates to system and method for discharging a charged source in the automotive chargers for high voltage safety.
[00035] An aspect of the present disclosure relates to a method for active discharge of a charged source of an automotive Electronic Control Unit (ECU). The ECU comprises a full bridge rectifier electrically coupled with the charged source, and having a first leg with a pair of switches M1 and M2, and a second leg with a pair of switches M3 and M4. The full bridge rectifier is electrically coupled with a power supply through a transformer. The method comprises: switching, by a control unit operatively coupled with the full bridge rectifier, the switch M2 of the first leg to the ON state and the switch M4 of the second leg to the OFF state, at a fixed duty cycle; and switching the switch M2 of the first leg to the OFF state and the switch M4 of the second leg to the ON state, at a fixed duty cycle; and switching, by the control unit, the switch M1 of the first leg and the switch M3 of the second leg between the ON state and the OFF state, wherein the switching of the switch M1 and the switch M3 is performed at a fixed frequency during the fixed duty cycle. During the switching of the switch M1 and the switch M3, overlapping of the ON state of the switch M1 with the ON state of the switch M2, and the OFF state of the switch M3 with the OFF state of the switch M4, creates a short-circuit across the charged source resulting in discharging of the charged source. During the switching of the switch M1 and the switch M3, overlapping of the OFF state of the switch M1 with the OFF state of the switch M2, and the ON state of the switch M3 with the ON state of the switch M4, creates a short-circuit across the charged source resulting in discharging of the charged source. The control unit is configured to facilitate supply of electric power stored in the charged source to each of the switches M1 and M2 of the first leg and the switches M3 and M4 of the second leg to enable switching of the pair of switches M1 and M2 of the first leg and the pair of switches M3 and M4 of the second leg between the ON state and the OFF state, leading to gate switching losses that also results in discharging of the charged source.
[00036] In an embodiment, the ECU may include any or a combination of automotive DC-DC converter, Inverter, On Board Charger (OBC), or integrated DCDC-OBC with high voltage safety.
[00037] In an embodiment, a nominal parasitic inductance of the ECU and the duty cycle facilitates to limit a current flow through each of the pair of switches at a predefined value during discharging of the charged source, and wherein the duty cycle is determined based on the nominal parasitic inductance of the ECU and voltage of a DC bus through which the first leg, the second leg, and the charged source are connected to each other.
[00038] In an embodiment, when the switching is performed at a fixed frequency during the fixed duty cycle, a current flows through each of the pair of switches at a predefined level that is within a predefined maximum rated current of each of the pair of switches.
[00039] In an embodiment, the control unit is configured to facilitate switching of the switch M1 of the first leg and the switch M4 of the second leg to the ON state, and the switch M2 of the first leg and the switch M3 of the second leg to the OFF state at a predefined duty cycle during a normal converter operation of the charger.
[00040] In an embodiment, the control unit is configured to facilitate switching of the switch M2 of the first leg and the switch M3 of the second leg to the ON state, and the switch M1 of the first leg and the switch M4 of the second leg to the OFF state at a predefined duty cycle during a normal converter operation of the charger.
[00041] In an embodiment, the ECU is electrically coupled to a high voltage battery through a set of switches S1 and S2, and wherein the control unit is configured to facilitate simultaneous switching of each of the switch S1 and the switch S2.
[00042] In an embodiment, the charged source of the ECU is a Direct Current (DC) Link capacitor.
[00043] Another aspect of the present disclosure a system for active discharge of a charged source of an automotive ECU charger. The ECU charger is a full bridge rectifier electrically coupled with the charged source, and having a first leg with a pair of switches M1 and M2, and a second leg with a pair of switches M3 and M4, wherein the full bridge rectifier is electrically coupled with a power supply through a transformer. The system comprises: a control unit comprising one or more processors, and electrically coupled with the full bridge rectifier, said control unit configured to: switch the switch M2 of the first leg to the ON state and the switch M4 of the second leg to the OFF state at a fixed cycle; and switch the switch M2 of the first leg to the OFF state and the switch M4 of the second leg to the ON state, at a fixed duty cycle; and switch the switch M1 of the first leg and the switch M3 of the second leg, between the ON state and the OFF state, wherein the switching of the switch M1 and the switch M3 is performed at a fixed frequency during the fixed duty cycle. During the switching of the switch M1 and the switch M3, overlapping of the ON state of the switch M1 with the ON state of the switch M2, and the OFF state of the switch M3 with the OFF state of the switch M4, creates a short-circuit across the charged source resulting in discharging of the charged source. During the switching of the switch M1 and the switch M3, overlapping of the OFF state of the switch M1 with the OFF state of the switch M2, and the ON state of the switch M3 with the ON state of the witch M4, creates a short-circuit across the charged source resulting in discharging of the charged source. The control unit is configured to facilitate supply of electric power stored in the charged source to each of the switches M1 and M2 of the first leg and the switches M3 and M4 of the second leg to enable switching of the pair of switches M1 and M2 of the first leg and the pair of switches M3 and M4 of the second leg between the ON state and the OFF state, leading to gate switching losses that also results in discharging of the charged source.
[00044] FIG. 1 illustrates an exemplary representation of system for discharging a charged source, in accordance with an embodiment of the present disclosure.
[00045] As illustrated, the system 100 comprises a full bridge rectifier 2 that comprises a first leg 3 and a second leg 4. The first leg 3 and the second leg 4 are parallelly connected to each other. The first leg 3 includes switches M1 and M2 being connected in series, whereas the second leg 4 includes switches M3 and M4 being connected in series. The system 100 includes a charged source 6 configured parallel to both the first leg 3 and the second leg 4. The first leg 3, the second leg 4, and the source 6 are connected parallel to each other through a DC bus. The system 100 is implemented for active discharge of a charged source of an automatic Electronic Control Unit (ECU) charger.
[00046] In an embodiment, each of the switches M1, M2, M3, and M4 includes an input terminal and an output terminal. The output terminal of M1 is connected to the input terminal of the switch M2. The input terminal of switch M1 and the output terminal of switch M2 forms two ends of the first leg 3. Similarly, the output terminal of M3 is connected to the input terminal of the switch M4. The input terminal of switch M3 and the output terminal of switch M4 forms two ends of the second leg 4. In an embodiment, each of the switches M1, M2, M3, M4 includes a gate terminal connected to the control unit, where the switching of the switches M1, M2, M3, M4 is controlled through the gate terminal.
[00047] In an embodiment, the system 100 includes an ac power supply 1 connected to the full bridge rectifier such that the ac power supply 1 is connected between a common terminal of M1 and M2, and a common terminal of switches M3 and M4. In another embodiment, the ac power supply 1 is connected to the full bridge rectifier through a transformer 5, in this case, the terminals of the ac power supply 1 is connected to input terminals of the transformer, whereas output terminals of the transformer are connected between the common terminal of the switches M1 and M2, and the common terminal of switches M3 and M4.
[00048] In an embodiment, the switches M1, M2, M3, and M4 may be either current controlled switches or voltage controlled switches or combination of both. In an embodiment, the switches may include, by way of example but not limited to, any or a combination of transistor, mosfet, thyristor, diode, triac, and so on. In an embodiment, each of the switches M1, M2, M3 and M4 are configured to switch between an ON state and an OFF state , whereas during the ON state, the switch allows current through the switch; and during the OFF state, switch does not allow current through the switch. In other words, the ON state provides low resistance path and the OFF state provides high resistance path.
[00049] In an embodiment, the system 100 comprises a control unit that is configured to switch each of the switches M1, M2, M3 and M4 between an ON state and OFF state. In an embodiment, the control unit may be implemented as a hardware component. In another embodiments, the control unit may be implemented as a computer program product, which may include a computer-readable storage medium employing a set of instructions. The control unit may include one or more processor(s). The one or more processor(s) may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, logic circuitries, and/or any devices that manipulate data based on operational instructions. Among other capabilities, the one or more processor(s) are configured to fetch and execute computer-readable instructions stored in a memory of the control unit. The memory may store one or more computer-readable instructions or routines, which may be fetched and executed to create or share the data units over a network service. The memory may comprise any non-transitory storage device including, for example, volatile memory such as RAM, or non-volatile memory such as EPROM, flash memory, and the like.
[00050] In an embodiment, the charged source 6 is configured parallel to the first leg 3 and the second leg 4. In an embodiment, the charged source 6 may include, by way of example but not limited to, a capacitor. In a preferred embodiment, the charged source includes, a Direct Current (DC) Link capacitor. The source 6 is connected to a high voltage battery 7 through one or more switches such as switches S1 and S2. In an embodiment, the ECU is electrically coupled to a high voltage battery 7 through a set of switches S1 and S2. In some embodiments, the control unit is configured to facilitate switching of each of the switch S1 and the switch S2 simultaneously. In some other embodiments, the control unit may be configured to facilitate switching of the switch S1 and the switch S2 alternatively.
[00051] In an embodiment, the source 6 is configured to charge when the switch S1 and S2 are in ON state. In other words, the switches S1 and S2 allows the high voltage source 7 to get connected to the source 6. When the switches S1 and S2 are in open position i.e. the high voltage source 7 not being connected to the source 6, the source 6 is discharged with switching of one or more switches of switches M1, M2, M3, and M4.
[00052] In an embodiment, based on switching of the switches M1, M2, M3, and M4, operation of the switches can be realized through four modes of operation, which can be understood through following description.
[00053] Mode 1: when the switches M1 and M2 are in ON state and M3 and M4 are in OFF state, the first leg 3 gets short-circuited and the second leg 4 becomes open circuited. In this mode of operation, the source 6 gets discharged through first leg 3, whereas there is no current flow in the second leg 4.
[00054] Mode 2: when the switches M1 and M2 are in OFF state and M3 and M4 are in ON state, the second leg 4 gets short-circuited and the first leg 3 becomes open circuited. In this mode of operation, the source 6 gets discharged through second leg 4, whereas there is no current flow in the first leg 3.
[00055] Mode 3: when the switches M1 and M4 are in ON state and M2 and M3 are in OFF state, the configuration of the switches M1, M2, M3, and M4 acts as an AC-DC converter, where operation of the AC- DC converter may be easily understood by a person skilled in the art. In an embodiment, the source 6 gets charged thorough the power supply received from the source 1.
[00056] Mode 4: Mode 4 is similar to the Mode 3. When the switches M1 and M4 are in OFF state and M2 and M3 are in ON state, the configuration of the switches M1, M2, M3, and M4 acts as an AC-DC converter. In an embodiment, the source 6 gets charged through the power received from the source 1.
[00057] In an embodiment, switching of switches M1 and M3 is carried out at a fixed frequency in all the four modes of operation, whereas the switching of switches M2 and M4 is carried out at a fixed duty cycle in all the four modes of operation.
[00058] In an embodiment, the time required to discharge the source 6 is considered as discharge time. The discharge time may depend on one or more parameters of the at least one of switches M1, M2, M3, and M4. The one or more parameters may include, by way of example but not limited to, duty cycle, switching frequency, and so on. In an example, discharge time can be reduced by controlling the duty cycle and switching frequency of one or more switches M1, M2, M3, and M4. The controlling of duty cycle and switching frequency may facilitate the smooth operation of the overall system.
[00059] In an embodiment, switching of switches between ON state and OFF state may allow change in the current passing though the switches. In an embodiment, when the switching is performed at a fixed frequency during the fixed duty cycle, a current flows through each of the pair of switches may limit to a predefined level that is within a predefined maximum rated current of each of the pair of switches. In other words, with the switching at high frequency and very small duty cycle, the current passing through the switches may be limited within the permissible range of the current. In addition, switching at high frequency and very low duty cycle also limits a rise in temperature of the components of the system 100, thereby eliminating the requirement of any additional thermal interfaces/cooling systems.
[00060] In an embodiment, the system 100 is configured in an automotive electronic control unit (ECU). The system 100 may include a nominal parasitic inductance 8 as shown in FIG. 1. The parasitic inductance 8 and the duty cycle may facilitate to limit a current flow through each of the pair of switches at a predefined value during discharging of the charged source. The duty cycle is determined based on the nominal parasitic inductance 8 and voltage of a DC bus through which the first leg, the second leg, and the charged source are connected to each other. In an example, the ECU may include any or a combination of automotive DC-DC converter, Inverter, On Board Charger (OBC), or integrated DC DC-OBC with high voltage safety.
[00061] FIG. 2 illustrates a block diagram of switching circuit 200 of the control unit, in accordance with embodiments of the present disclosure.
[00062] As illustrated, the control unit comprises a switching circuit 200 configured to facilitate switching of switches M1, M2, M3, and M4 between an ON state and OFF state. In an exemplary embodiment, switching of M1, M2, M3, and M4 may follow a particular sequence in order to execute four modes of operation. In FIG. 2, the block 201 represents HV supply to be supplied to block 203. The HV supply is received from either the source 1 or the source 7. The block 203 represents the charged source that includes, a dc link capacitor. The charged source supplies electric power to block 205. The block 205 represents power circuits for gate drivers. Such power circuits may include any or a combination of flyback converter, forward converter, push pull dc-dc converter and the like. The power circuits 205 supplies power to block 207. The block 207 represents gate drivers circuits, where the gate driving circuits provides one or more command for switching of at least one of switches M1, M2, M3, and M4. Such commands includes pulse width modulation (PWM) command that is provided to gate terminals of at least one of switches M1, M2, M3, and M4. The block 209 represents a controller that is configured to provide PWM command to gate drivers. As can be seen that the power supply for the gate driver are received from the charged source. Therefore, switching circuits can be effectively utilized for switching of the charged source. In this manner, discharge of the charged source can be achieved in two ways –
a) switching of switches M1, M2, M3, and M4
b) short circuiting the DC link capacitor
[00063] FIGs. 3A and 3B illustrate exemplary representations of switching pattern 1 and corresponding current through switches, in accordance with embodiments of present disclosure. As shown in FIG. 3A, there are two pulse that are applied to switches M1, M2, M3, and M4. The upper pulse waveform is applied to either/both of M1 and M3; and lower pulse waveform is applied to either/both of M2 and M4; and vice versa. In an example, the upper waveform is applied to M1; and lower pulse waveform is applied to M2. In another example, the upper pulse waveform is applied to M3 and the lower pulse waveform is applied to M4.. As shown in FIG. 3A, the duty cycle of the upper pulse waveform is lower than the duty cycle of the lower pulse waveform, however, in some case, the duty cycle of the upper pulse waveform may be greater than the duty cycle of the lower pulse waveform. In the duration for which any of the switches M1, M2, M3, and M4 are switched to ON/ OFF state, the charged source gets discharged due to switching loss occured in switches M1, M2, M3, and M4, also considered as gate switching losses.
[00064] In an embodiment, time for which both the lower pulse waveform and the upper pulse waveform get overlapped to each other, then the switches M1, M2, M3, and M4 are operated in either in Mode 1 or in Mode 2. In this mode of operation, the charged source is short-circuited also known as dead short. As shown in FIG. 3A, the overlapping area represents the discharge of the charged source due to dead short.
[00065] FIG. 3B shows the current passing through the switches M1, M2, M3, and M4 during the switching pattern 1. As shown in FIG. 3B, during the overlapping period, the current through the switches increases, and when the overlapping period ends, current starts to decrease.
[00066] FIG. 4 illustrates an exemplary representation of switching pattern 2, in accordance with embodiments of present disclosure. In FIG. 4, pulses P1, P2, P3, and P4 may correspond to pulses for switching of switches M1, M2, M3, and M4, respectively. In this switching pattern, the overlapping period may be same as of the overlapping period of the switching patten 1, however, the switching frequency of the switching pattern 2 is greater than switching frequency of the switching pattern 1. In other words, the overlapping period or the duration for which dead short occurs, is same as of the switching pattern 1, however, the transition from one state to another (ON to OFF or OFF to ON) is increased. Due to increase in transitions of switches between ON state and OFF state, switching loss for the switching gets increased. In an example, compared to switching pattern 1, switching pattern 2 have additional switching intervals P1, P3 during which the switch M1 alone is switched to ON state and M2 is switched to OFF state & the intervals P2, P4 during which M2 alone is switched to ON state and M1 is switched to OFF state. Since the switching intervals P1, P2, P3, and P4 do not have common overlapping, therefore there is no dead short/ short circuit occurs for the charged source. However, to switch M1 and M2 to ON state and to OFF state during these intervals at a cyclical frequency, there is considerable power consumption required from the power circuits of the gate drivers which is received from the charged source as indicated in FIG. 2. Although the majority of discharge of charged source occurs during the overlapping period where both the switches i.e. M1 and M2 are ON, intervals P1 to P4 aid in discharging the charged source through switching losses.
[00067] Therefore, the charged source discharges more rapidly in switching pattern 2 compared to switching pattern 1. Therefore, the discharge time for the switching pattern 2 may be lower than the discharge time of the switching pattern 1.
[00068] FIG. 5 illustrates an exemplary representation showing a relation between discharge time vs HV voltage, in accordance with embodiments of present disclosure.
[00069] FIG. 5 shows a relation between discharge time and HV voltage at different frequencies. As shown in FIG. 5, slopes 1, 2, 3, 4 may correspond to different frequencies f1, f2, f3, f4, respectively, where f1>f2>f3>f4. In this manner, FIG. 5 indicates how the slope varies with variation of frequencies.
[00070] Those skilled in the art would appreciate that the embodiments of the present disclosure provides a system for discharging the charged resource. Embodiments herein deal with discharging mechanism with dead short and the switching losses, which provides dual ways for discharging the charged source. In this manner, time required for discharging the charged source, also known as discharge time, get reduced. Further, with the higher switching frequency, switching losses increase which further reduces the discharge time for the charged source.
[00071] Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refer to at least one of something selected from the group consisting of A, B, C ….and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.
[00072] While some embodiments of the present disclosure have been illustrated and described, those are completely exemplary in nature. The disclosure is not limited to the embodiments as elaborated herein only and it would be apparent to those skilled in the art that numerous modifications besides those already described are possible without departing from the inventive concepts herein. All such modifications, changes, variations, substitutions, and equivalents are completely within the scope of the present disclosure. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims.

ADVANTAGES OF THE INVENTION
[00073] The present disclosure provides method and system for discharging a charged source for high voltage safety without additional components.
[00074] The present disclosure provides a cost-effective system that is easy to implement and compact in size.
[00075] The present disclosure provides a system that requires a minimal number of components.
[00076] The present disclosure provides method and system that limit temperature rise of the components and thereby eliminating requirements of any additional thermal interfaces.
[00077] The present disclosure provides method and system that discharge a charged source with a lesser time compared to conventional methods and systems.