DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
STARTING AND CHARGING MECHANISM FOR INTERNAL COMBUSTION ENGINES
APPLICANT:
Varroc Engineering Limited
An Indian entity having address as:
L-4, MIDC Waluj,
Aurangabad 431136,
Maharashtra, India

The following specification particularly describes the invention, and the manner in which it is to be performed.
TECHNICAL FIELD
The present disclosure relates to the field of automobiles. More particularly, the present disclosure relates to a mechanism for starting an engine of a vehicle and charging a battery of the vehicle.
BACKGROUND
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed technology.
In the existing art, an integrated starter generator has been utilized for performing dual functions of starting or cranking an internal combustion engine (hereinafter referred to as ICE) and charging a battery or supplying power to electrical appliances of the vehicle during operation of the ICE. Typically, the integrated starter generator comprises a three-phase electrical machine. Further, the three-phase electrical machine is connected to an engine shaft either through direct mounting on the engine shaft or connected to the engine shaft using a belt-pulley/chain sprocket type arrangement. Further, the three-phase electrical machine is configured to act as a motor during cranking or starting of ICE, and as a generator once the ICE is in operation. Further, the motoring and charging operation of the three-phase electrical machine are controlled by various techniques, in combination with at least one electrical circuit. However, the conventional methodologies for controlling motoring and charging operation for the ICE suffers from several limitations/drawbacks as described below.
The state-of-the-art control methods for motoring and charging operation for ICE using three phase electrical machine comprises two types of circuit and control topologies. One of the known methods includes usage of an inverter circuit and phase lag/advancing type of techniques for generating a regulated DC voltage from alternating back-EMF (hereinafter referred to as BEMF) generated by the three-phase electrical machine. When the BEMF generated is lower than that required output voltage, the techniques use the three-phase electrical machine winding inductance to boost the output voltage using phase lagging control. Alternatively, when the BEMF generated is higher than the regulated output voltage, these techniques work on the principle of dissipating the excess power, other than that required by load, at the source itself (three phase electrical machine in this case). Hence, this method is inefficient especially at low loads, and ultimately affects the fuel economy of the engine.
Further, the aforementioned method can also have a potential disadvantage of large amplitude of circulating currents flowing through the windings of the three-phase electrical machine. This can result in excessive heating of windings, which may lead to effects such as insulation degradation and/or deterioration of the properties of permanent magnets used in rotor of three phase electrical machine. This in turn leads to use of copper wires with higher grade of insulation and magnets with higher grade of magnetization for ensuring the mission life of the three-phase electrical machine. This approach being inefficient, consequently also requires larger heat dissipation mechanisms in the controller and three phase electrical machine, which can potentially nullify the size and cost advantage gained by implementing a simpler circuit & control topology.
Further, another known method includes utilizing separate circuits, i.e., inverter and rectification-regulation circuit, with a combination of phase advance/lag and series regulation (phase angle-controlled rectification) techniques. In this method, based on the characteristics of the generated BEMF with respect to speed, the three-phase electrical machine may generate BEMF less than battery voltage up to a certain speed. Till this speed point, phase lagging or PWM rectification type techniques are used to boost and regulate the output DC voltage at a value above the battery voltage so that battery can be charged. Once the engine speed (and in turn, the speed of three phase electrical machine) goes above a certain threshold, the three-phase electrical machine starts generating BEMF more than the battery voltage. In this condition, series regulation techniques such as, but not limited to, phase angle-controlled rectification is used. In the series regulation techniques, the source is disconnected from the load when the power demand of the load is met, which results into higher efficiency of regulation. Also, it does not involve any adverse effects of phase advancing/shunting type of techniques on the three-phase electrical machine. The three-phase electrical machine can be designed such that the range of engine speed in which phase lagging/advancing techniques are used, is outside the most commonly used range of engine speed, while series regulation techniques are used in the most commonly used range of engine speed, in order to achieve higher efficiency. Hence, this approach turns out to be more efficient and gentler on the three-phase electrical machine. However, this approach is more complicated in terms of control implementation and involves greater number of electronic components which results in bigger size of controller for the same level of power of three phase electrical machine.
Therefore, there is a long felt need for an improved compact circuit topology containing lesser number of parts to support multiple regulation techniques depending on the design of electrical machine for providing higher efficiency regulation of output voltage and better fuel economy of the engine.
SUMMARY
This summary is provided to introduce concepts related to a mechanism for starting an engine of a vehicle and charging a battery of the vehicle. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
In one embodiment, a system for starting and charging in a motor vehicle is disclosed. The system may comprise a battery and a multi-phase electrical machine connected to the battery. Further, the multi-phase electrical machine may be configured to start an engine of the motor vehicle and charge battery of the motor vehicle, by operating in one of a starting mode and a charging mode. Further, the system may comprise a processing unit, a series control switch which may comprise a first set of power switching devices, an inverter control switch which may comprise a second set of power switching devices. Further, the system may comprise one or more current sensing means, a first driving circuit and a second driving circuit. Further, the first driving circuit may be configured to drive the series control switch, and the second driving switch may be configured to drive the inverter control switch. Further, during the starting mode, the processing unit may be configured to start the multi-phase electrical machine by triggering the first driving circuit and the second driving circuit to switch ON the first set of power switching devices and switching ON one or more power switching devices from the second set of power switching devices. Further, during the charging mode, the processing unit may be configured to determine whether to perform boosting or step-down regulation operation based on at least one of speed of the multi-phase electrical machine and current measured by the one or more current sensing mean. Further, the processing unit may be configured to perform the boosting or the step-down regulation operation using one of: a boost mode, a series regulation mode, and a shunt regulation mode. Further, the boost mode, the series regulating mode, or the shunt regulation mode may be enabled by triggering the first driving circuit and the second driving circuit. Further, the first driving circuit and the second driving circuit may be triggered to switch ON one or more power switching devices from the first set of power switching devices and one or more power switching devices from the second set of power switching devices.
In another embodiment, a method for starting and charging in a motor vehicle is disclosed. Further, the method comprises operating, via a processing unit, a multi-phase electrical machine in a starting mode to start the engine of the motor vehicle. Further, the motor vehicle is started by triggering the first driving circuit and the second driving circuit, to switch ON the first set of power switching devices and also switching ON one or more power switching devices from the second set of power switching devices. Further, the multi-phase electrical machine enters a charging mode when the multi-phase electrical machine starts operating above a pre-determined speed. Further, the method comprises determining, by the processing unit, whether to perform boosting or step-down regulation operation based on at least one of speed of the multi-phase electrical machine and current measured by one or more current sensing means. Further, the method comprises performing, by the processing unit, the boosting or the step-down regulation operation using one of: a boost mode, a series regulating mode, and a shunt regulation mode. It must be noted herein that the boost mode, the series regulating mode, or the shunt regulation mode may be enabled by triggering the first driving circuit and the second driving circuit to switch ON one or more power switching devices and one or more power switching devices from the second set of power switching devices.
In one embodiment, the multi-phase electrical machine during motoring may be controlled using multiple techniques such as 120° commutation, field-oriented-control (FOC) etc. with or without rotor position sensors.
In one embodiment, when the engine is successfully cranked, the system may enter into a generation mode. In an embodiment, the multi-phase electrical machine may start generating a Back-emf (BEMF), which varies in a fixed proportion with respect to the speed of the engine. Further, if the generated BEMF is less than the battery voltage after rectification, the system enters ‘boost’ mode. Further, in the boost mode, Pulse Width Modulation (PWM) rectification or phase lag type of techniques may be used to boost and regulate the voltage above battery voltage in order to charge the battery. Further, when the generated BEMF is above the battery voltage and within the voltage handling capability of the power switching devices, the system may enter ‘series regulation’ mode. Further, in the series regulation mode, the power switching devices are controlled such that the multi-phase electrical machine output may be connected and disconnected from the battery depending on the rotor position and the load requirements.
In one embodiment, when the BEMF from the multi-phase electrical machine output exceeds the voltage handling capability of the power switching devices, it becomes necessary to limit the voltage appeared across the power switching devices and regulate the output voltage at the same time. Further, to regulate such voltage, the system may enter ‘shunt’ mode. In this case, shunting or phase advance type of techniques may be used to regulate the output voltage. In this shunt mode, the excess power, which is more than that required by the load, generated by the multi-phase electrical machine may be dissipated in the windings of the multi-phase electrical machine, in order to regulate the output voltage. The shunt mode is operated at a multi-phase electrical machine speed range which typically lies outside of the operating cycle of the engine. Further, such controlling of the multi- phase electrical machine output ensures generation of smooth and regulated DC voltage at the output from BEMF of the multi-phase electrical machine.
BRIEF DESCRIPTION OF FIGURES
The detailed description is described with reference to the accompanying Figures. In the Figures, the left-most digit(s) of a reference number identifies the Figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.
Figure 1 illustrates a circuit 100 utilized in starting and charging system, in accordance with an embodiment of the present subject matter.
Figure 2 illustrates an exemplary operating state 200 of the circuit 100 when the starting and charging system is operating in a motoring mode, in accordance with an embodiment of the present subject matter.
Figure 3 illustrates a circuit waveform 300 when the starting and charging system is in the motoring mode, in accordance with an embodiment of the present subject matter.
Figure 4 illustrates a BEMF waveform 400, in accordance with an embodiment of the present subject matter.
Figure 5 illustrates an exemplary operating state 500 of the circuit 100 when the system operates in a boost mode, in accordance with an embodiment of the present subject matter.
Figure 6 illustrates a circuit waveform 600 when the system operates in the boost mode, in accordance with an embodiment of the present subject matter.
Figure 7 illustrates an exemplary operating state 700 of the circuit 100 when the system operates in a series regulation mode, in accordance with an embodiment of the present subject matter.
Figure 8 illustrates a circuit waveform 800 when the system operates in the series regulation mode, in accordance with an embodiment of the present subject matter.
Figure 9 illustrates a circuit waveform 900 when the system operates in the shunt regulation mode, in accordance with an embodiment of the present subject matter.
Figure 10 illustrates a flowchart 1000 of a starting and charging mechanism for starting an engine of a vehicle and charging a battery of the vehicle, in accordance with an embodiment of the present subject matter.
Figure 11 illustrates a method 1100 for the starting and charging mechanism for starting an engine of a vehicle and charging a battery of the vehicle, in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION
Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment” in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
The present disclosure relates to a starting and charging system for starting the ICE and charging the battery and powering other DC electrical and electronic loads. Further, the system comprises a multi-phase electrical machine or ISG. The multi-phase electrical machine may be connected to and controlled by a compact circuit topology. Further, the compact circuit topology may enable multiple regulation techniques for achieving higher efficiency regulation of output voltage and better fuel economy of the engine.
Referring to figure 1, a circuit (100) utilized in starting and charging system is illustrated, in accordance with an embodiment of the present subject matter. As shown, the system may comprise a processing unit (101), a series control switch (102), an inverter control switch (103), one or more current sensing means (104) and (106), a multi-phase electrical machine (105), a plurality of driving circuits (107), (108) and (109), a DC bus link capacitor (110), a DC bus link capacitor protection switch (111), and a battery (112).
In one embodiment, the series control switch (102) and the inverter control switch (103) may be configured to connect the multi-phase electrical machine (105) with the battery (112). Further, the series control switch (102) and the inverter control switch (103) may comprise a first set of power switching devices and a second set of power switching devices. In an exemplary embodiment, the first set of power switching devices and the second set of power switching devices include semiconductor power switching devices selected from, but are not limited to, MOSFETs, IGBTs, power BJTs, and the like.
In one embodiment, the one or more current sensing means (104) and (106) may be selected from, but are not limited to, a series element based current sensors such as current sensing resistors coupled with analog signal amplification circuits or contactless current sensing mechanisms such as Hall-effect based sensors, and the like.
In one embodiment, the multi-phase electrical machine (105) may be an integrated starter generator (ISG). The ISG may be selected from, but is not limited to, a Brushless type DC motor (BLDC) or permanent magnet synchronous machine, and the like.
In one embodiment, the system may comprise a plurality of driving circuits (107), (108), and (109). The plurality of driving circuits may be configured to trigger the DC bus link capacitor protection switch (111), the series control switch (102) and the inverter control switch (103).
In one embodiment, the DC link bus capacitor (110) may be connected to the multi-phase electrical machine control unit (102 and 103) and the battery (112). In one embodiment, the DC link bus capacitor (110), may be configured to be used during motoring operation and generation operation thereby reducing the size and number of capacitors. Further, the DC link bus capacitor (110) may be selected from, but not limited to, aluminium electrolytic capacitors, ceramic capacitors, film capacitors, and the like.
In one embodiment, the DC bus link capacitor protection switch (111) may be a semiconductor power switching device selected from, but is not limited to, MOSFETs, IGBTs, power BJTs, and the like. Further, the DC bus link capacitor protection switch (111) may be configured to disconnect the DC bus link capacitor (110) from the battery (112) in case the battery (112) is inadvertently connected in the reverse polarity.
In one embodiment, the processing unit (101) may be configured to control the series control switch (102) and the inverter control switch (103) using continuous ON/OFF type control or PWM control, based on at least one of: the current measured by the one or more current sensing means (104) or (106), and the speed of the multi-phase electrical machine (105), the details of which are hereinafter explained below.
In an embodiment, the multi-phase electrical machine (105), or ISG may be configured for the starting and charging system for ICE. The multi-phase electrical machine may be configured to crank the ICE during starting. In an embodiment, the multi-phase electrical machine may be configured to act as a motor to start the ICE up to a predetermined speed. Further, after attaining the predetermined speed the multi-phase electrical machine (105) may act as a generator to generate Back-emf or BEMF as an output voltage. In an embodiment, the generated BEMF may be converted to regulated DC voltage to charge the battery (112) or provide power to other appliances associated to the vehicle. However, the generated BEMF may vary according to the speed of a rotor in the multi-phase electrical machine (105), which may result in instances. In one non-limiting embodiment, the rectified value of BEMF generated may be higher or lower than a predetermined value of regulated DC voltage. Therefore, to control the regulated DC output voltage, various control methods are used, which are described in detail in the following paragraphs.
Now, referring to figure 2, an exemplary operating state 200 of the circuit 100 is depicted when the starting and charging system is operating in a motoring mode, in accordance with an embodiment of the present subject matter. Further, the starting and charging system may enter the motoring mode during the cranking of the engine. As shown in figure 2, a plurality of inductors represent the inductance offered by the phase windings of the multi-phase electrical machine (105) and arrows indicate direction of current flow. Further, the circuit may comprise a series control switch (102). In one embodiment, the series control switch (102) may comprise a first set of power switching devices M1, M2 and M3. Further, the inverter control switch (103) may comprise a second set of power switching devices M4, M5, M6, M7, M8, and M9. It should be noted to one skilled in the art that the arrangement of the first set of power switching devices and the second set of power switching devices is such that the body diodes of both are connected to oppose the current flow from one another. This arrangement provides the reverse polarity protection for the power stage (first set of power switching devices and second set of power switching devices together) of the circuit.
During motoring, switches M1 to M3 may be fully turned ON in order to connect the inverter control switch (103) with the battery (112). Further, a switch M10 may be also turned ON for connecting the DC bus link capacitor (110) with the battery (112). Further, the switches M4 to M9 may be controlled on the basis of motor control technique used, the rotor position and speed of the ISG. In an exemplary embodiment, the switches M4 to M6 may be controlled with a Pulse width Modulation (PWM) type of control system from the processing unit (101) (not shown in the figure). Further, again referring to figure 2, the current may flow through switches M1 and M4 to L1 phase of the motor and returns through phase L2 and switch M8, back to the battery and DC bus link capacitors (110).
Now, referring to Figure 3, a waveform 300 of one of the phases of the multi-phase electrical machine when the starting and charging system is operating in a motoring mode is illustrated, in accordance with an embodiment of the present subject matter. As can be seen from the figure 3, the plot of line voltage represents the BEMF generated during motoring, which may be lesser than the battery voltage. Further, referring to figure 3, it may be noted that during motoring, switch M1 may be continuously turned ON, and switches M4 and M7 may be operated in complementary (ON/OFF) mode with PWM type of signals.
Now, referring to Figure 4, an alternating BEMF waveform 400 is illustrated, in accordance with an embodiment of the present subject matter. The starting and charging system may enter generator mode herein, which may result in high alternating BEMF generations as compared to motoring. Now, referring to figure 4, it can be observed that BEMF waveforms of 3 phases may be shifted by 120°, which means that different phases will have the maximum positive and negative voltages respectively at different electrical angle of the rotor of the multi-phase electrical machine (105).
In one embodiment, referring to Figure 4, Phase 1 may have a maximum voltage in positive magnitude while Phase 2 may have maximum voltage in negative magnitude between electrical angle of 30° to 90°. Further, this also means that during this angle or rotor position, only phase 1 and phase 2 of the multi-phase electrical machine (105) are capable of supplying power back to the battery and hence, only they should be connected to the battery through the series control switches. This variation of BEMF in each phase of the multi-phase electrical machine, with respect to other phases as well as with respect to the speed of rotation of the multi-phase electrical machine, forms the very basis of voltage control during generation mode. In accordance with embodiments of the present disclosure, the voltage control may be enabled via one of: a boost mode, a series regulation mode, and a shunt mode, which are explained hereinafter in the following paragraphs.
Now, referring to Figure 5, an exemplary operating state 500 of the circuit 100 for operating the system in a boost mode is illustrated, in accordance with an embodiment of the present subject matter. It must be noted that, when the BEMF generated is less than the battery voltage, the system may be configured to activate the boost mode during the generation mode. In one embodiment, in the boost mode, the switches M1- M10 may be controlled in such a way that the windings of the multi-phase electrical machine (105) may be used as inductors to store energy which may be used to boost output voltage using PWM rectification or phase lagging type techniques. Now, still referring to figure 5, for operating the system in the boost mode using PWM rectification technique, the switches M1 to M3 and M10 may be kept continuously ON and are configured to connect the multi-phase electrical machine (105) to the battery (112). Further, the switches M4 to M9 may be controlled based on the load requirement and the electrical position of the rotor. Further, in an embodiment, while controlling combination of switches from M4 to M6 and M7 to M9, one of the switches from M7 to M9 is kept continuously ON while one of the switches from M4 to M6 is operated with PWM control, complementary to the corresponding switch from M7 to M9, depending on the electrical angle or the rotor position.
In an embodiment, the switches M4 and M7 may be controlled with complementary PWM Control and M8 may be kept ON. Further, when M7 and M8 are both ON, the phase windings L1 and L2 may get short circuited and store energy. Further, when the switch M7 may be turned OFF, and M4 may be turned ON, this stored energy may be released as boosted output voltage.
Now, referring to Figure 6, a circuit waveform 600, when the circuit may be operated in the boost mode is depicted, in accordance with an embodiment of the present subject matter. Further, with reference to the embodiment illustrated above, the complementary PWM operation of M4 and M7 and continuous operation of M1 and M8 results into boosting and regulating the output voltage to a desired value.
Now, referring to Figure 7, an exemplary operating state 700 of the circuit 100, when the system may be operating in a series regulation mode is depicted, in accordance with an embodiment of the present subject matter. Further, when the BEMF generated in the system is higher than the battery voltage, and also less than the voltage rating of the power switching devices, the system may activate series regulation mode during the generation mode. Further, in the series regulation mode, the switch combination of M1 and M4, M2 and M5, and M3 and M6 from the upper part of the circuit may be operated in tandem with switches M7, M8 and M9 from the lower part. Further, the appropriate operation may depend on the electrical position of the rotor and load requirements from current as sensed by the one or more current sensing means 104 and 106 and the value of regulated DC output voltage. Further, in the series regulation mode, the control of the firing or conduction period of the switches during each phase is such that 2 phases with the highest BEMF at that moment in time are connected to the battery and ground, respectively.
In an embodiment, referring to Figure 7, switches M1 and M4 may be turned ON along with switch M7, thus connecting the multi-phase electrical machine (105) to the battery and thereafter establishing a current flow thereto. Now, referring to Figure 8, which illustrates a circuit waveform 800, when the circuit may be operated in the series regulation mode, in accordance with an embodiment of the present subject matter. Further, it may be seen the combination of turning ON switches M1, M4 and M7 during high BEMF generation in a single phase, resulting in a connection between the multi-phase electrical machine 105 to the battery. Further, the connection between multi-phase electrical machine 105 to the battery during series regulation mode may charge the battery and may prevent power dissipation on the switches M1-M10.
Now, referring to Figure 9, a circuit waveform 900, when the system may be operated in the shunt regulation mode is depicted, in accordance with an embodiment of the present subject matter. Whenever the generated BEMF exceeds the battery voltage, and even beyond the voltage rating of the power switches, the system activates shunt control mode during the generation mode. Further, in one embodiment, the switches M1 to M3 and M10 (shown in Figure 7) may be continuously ON, in order to connect the multi-phase electrical machine 105 to the battery. Further, the way M4 to M6 and M7 to M9 (shown in Figure 7) are controlled may be different and may be done in multiple ways. For example, in shunting mode, a technique like phase advance control may be used. Further, in this method, the switches M4 to M6 (depending on the exact electrical angle of the rotor) may be turned ON and OFF in such a way that a switch corresponding to a particular phase is turned ON much before the phase voltage reaches the maximum positive or negative magnitude point (as described in Figure 4, for example 30° point for Phase 1), to obtain a lower output voltage. Further, in this case shunting or phase advance type of techniques may be used to regulate the output voltage. Further, the excess power generated during advancing the phase, which may be more than that required by the load, may be dissipated in the windings of the multi-phase electrical machine 105, in order to regulate the output voltage. Though these techniques are inefficient in nature, the multi-phase electrical machine 105 may be designed such that the speed range which belongs to shunt mode may lie outside that in typical operating cycle of the engine.
Now, referring to Figure 10, a flowchart 1000 of a starting and charging mechanism for starting an engine of a vehicle and charging a battery of the vehicle is illustrated, in accordance with an embodiment of the present subject matter.
In one embodiment, to start the ICE, the multi-phase electrical machine 105 may enter a starting or a motoring mode. Further, during the motoring mode, the multi-phase electrical machine 105 may be configured to act as a motor to crank the ICE. The multi-phase electrical machine 105 may be controlled using multitudes of techniques such as 120° commutation, field-oriented-control (FOC) etc., with or without rotor position sensors.
Once the engine is started, either using the multi-phase electrical machine 105 or using any other means, the system may enter a generation mode. Further, on the basis of the engine speed, the BEMF generated by the multi-phase electrical machine 105 may vary in a fixed proportion. Further, if the BEMF is less than battery voltage after rectification, the system may activate ‘boost’ mode. In the boost mode, PWM rectification or phase lag type of techniques may be used to boost and regulate the voltage above the battery voltage in order to charge the battery. Further, if the BEMF is higher than the battery voltage and lesser the voltage handling capability of power switching devices, the system may activate ‘series regulation’ mode. In the series regulation mode, the power switches may be triggered by the first driving circuit 108 and the second driving circuit 109 such that the phase of the multi-phase electrical machine 105 output which produces maximum voltage output may be connected to the battery 112. Further, the connection of multi-phase electrical machine 105 to the battery 112 depends on the rotor position and the load requirement for generating smooth and regulated DC voltage at the output. Further, if the BEMF from the multi-phase electrical machine 105 exceeds the voltage handling capability of the battery 112 and the power switching devices, it becomes necessary to limit the voltage appeared across the power switching devices and regulate the output voltage at the same time. Therefore, the system may activate ‘shunt’ mode. Further, in this case shunting or phase advance type of techniques may be used to regulate the output voltage. In these control techniques, the excess power, which is more than that required by the load, generated by the multi-phase electrical machine 105 may be dissipated in the windings of the multi-phase electrical machine 105) in order to regulate the output voltage. This way, functional requirements of the system may be met, while keeping overall efficiency of the system within acceptable range during typical operating cycle of the engine. This also helps in selecting power devices with relatively lower voltage ratings, which results in smaller controller size and lesser cost.
Now, referring to Figure 11, a method 1100 of starting and charging mechanism for starting an engine of a vehicle and charging a battery of the vehicle is depicted, in accordance with an embodiment of the present subject matter. Further, the method comprises a first step of starting (1102) the motor vehicle using a multi-phase electrical machine 105 in a starting mode. In the starting mode, the processing unit 101 is configured to start the multi-phase electrical machine 105 by switching ON the first set of power switching devices, and also switching ON one or more power switching devices from the second set of power switching devices. Further, the first set of power switching devices and the second set of power switching devices are triggered by the plurality of driving circuits 108, 109. Further, after starting, when the multi-phase electrical machine 105 operates above a pre-determined speed, the multi-phase electrical machine 105 may enter a charging mode. Further, after entering charging mode, the multi-phase electrical machine10 may produce an alternating BEMF. Further, the method comprises determining (1104), by the processing unit 101, whether to perform boosting or step-down regulation operation based on at least one of speed of the multi-phase electrical machine 105 and current measured by one or more current sensing means 104, 106. Further, the method may comprise performing (1106), by the processing unit (101), the boosting or step-down regulation operation using one of: a boost mode, a series regulation mode, and a shunt regulation mode, based on the feedback signal. Further, the boost mode, the series regulating mode, or the shunt regulation mode are enabled by switching ON one or more power switching devices from the first set of power switching devices and one or more power switching devices from the second set of power switching devices via the plurality of driving circuits 108), 109.
The embodiments, examples and alternatives of the preceding paragraphs or the description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.
Although implementations for the starting and charging mechanism for internal combustion engines have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations for the starting and charging mechanism for internal combustion engines.
,CLAIMS:WE CLAIM:

1. A system for starting and charging in a motor vehicle, the system comprising:
a battery (112);
a multi-phase electrical machine (105) configured to start an engine of the motor vehicle and charge the battery (112) of the motor vehicle, by operating in one of a starting mode and a charging mode;
a processing unit (101);
a series control switch (102) comprising a first set of power switching devices;
an inverter control switch (103) comprising a second set of power switching devices;
one or more current sensing means ((104), (106));
a first driving circuit (108) configured to drive the series control switch (102), and a second driving circuit (109) configured to drive the inverter control switch (103);
wherein
during the starting mode,
the processing unit (101) is configured to start the multi-phase electrical machine (105) by triggering the first driving circuit (108) and the second driving circuit (109), respectively, to switch ON the first set of power switching devices, and one or more power switching devices from the second set of power switching devices;
during the charging mode,
the processing unit (101) is configured to:
determine whether to perform boosting or step-down regulation operation based on at least one of speed of the multi-phase electrical machine (105) and current measured by the one or more current sensing means ((104), (106)), and
perform the boosting or the step-down regulation operation using one of: a boost mode, a series regulation mode, and a shunt regulation mode, wherein
the boost mode, the series regulating mode, or the shunt regulation mode are enabled by triggering the first driving circuit (108) and the second driving circuit (109), to switch ON one or more power switching devices from the first set of power switching devices and one or more power switching devices from the second set of power switching devices.

2. The system as claimed in claim 1, further comprising a DC link bus capacitor (110) connected to the battery (112) through a power switching device, wherein the DC link bus capacitor (110) is configured to reduce DC bus ripple voltage during motoring, the boosting operation, the series regulation operation, and the shunt regulation operation.

3. The system as claimed in claim 2, wherein the DC bus link capacitor (110) is connected to a DC bus link capacitor protection switch (111) driven by a driving circuit (107), and wherein the DC bus link capacitor protection switch (111) is configured to disconnect the DC bus link capacitor (110) from the battery (112) in case the battery (112) is inadvertently connected in reverse polarity.

4. The system as claimed in claim 1, wherein the multi-phase electrical machine (105) comprises multi-phase windings configured to offer inductance through a plurality of inductors.

5. The system as claimed in claim 1, wherein the processing unit (101) is further configured to determine an induced voltage based at least on one of: speed of the multi-phase electrical machine (105) and the DC current.

6. The system as claimed in claim 5, wherein the processing unit (101) is configured to:
enable the boost mode when the induced voltage is lower than the battery voltage and boost the induced voltage using the multi-phase windings inductors by switching ON one or more power switches from the first set of power switching devices and one or more power switches from the second set of power switching devices using PWM rectification or phase lagging type techniques.

7. The system as claimed in claim 5, wherein the processing unit (101) is configured to:
enable the series regulation mode, when the induced voltage is higher than the required battery voltage, but lower than the voltage rating of the one or more of the first set of power switching devices and the second set of power switching devices, and regulate the induced voltage by switching ON one or more power switches from the first set of power switching devices and one or more power switches from the second set of power switching devices such that the phases with the highest induced voltage during operation are connected to the battery and ground.

8. The system as claimed in claim 5, wherein the processing unit (101) is configured to:
enable the shunt regulation mode when the induced voltage is higher than the required battery voltage as well as the voltage rating of the one or more of the first set of power switching devices and the second set of power switching devices, and regulate the induced voltage by switching ON one or more power switches from the first set of power switching devices and one or more power switches from the second set of power switching devices using a phase advance control technique.

9. The system as claimed in claim 1, wherein the power switching devices of the series control switch (102) or the inverter control switch (103) are selected from a group comprising MOSFETs, IGBTs, power BJTs, and combinations thereof, and wherein the series control switch (102) comprises a plurality of diodes connected in reverse polarity with respect to the inverter control switch (103).

10. A method (1100) for starting and charging in a motor vehicle, the method comprising:
operating (1102), via a processing unit (101), a multi-phase electrical machine (105) in a starting mode by triggering the first driving circuit (108) and the second driving circuit (109), respectively, to switch ON the first set of power switching devices, and one or more power switching devices from the second set of power switching devices and entering the multi-phase electrical machine (105) into a charging mode when the multi-phase electrical machine (105) starts operating above a pre-determined speed;
determining (1104), by the processing unit (101), whether to perform boosting or step-down regulation operation based on at least one of speed of the multi-phase electrical machine (105) and the current measured by one or more current sensing means ((104), (106)); and
performing (1106), by the processing unit (101), the boosting or the step-down regulation operation using one of: a boost mode, a series regulation mode, and a shunt regulation mode, wherein
the boost mode, the series regulating mode, or the shunt regulation mode are enabled by triggering the first driving circuit (108) and the second driving circuit (109) to switch ON one or more power switching devices from the first set of power switching devices and one or more power switching devices from the second set of power switching devices.

11. The method as claimed in claim 10, further comprising determining, by the processing unit (101), an induced voltage based at least on one of multi-phase electrical machine (105) and DC current.

12. The method as claimed in claim 11, further comprising:
enabling the boost mode when the induced voltage is lower than the battery voltage; and
boosting the induced voltage using the multi-phase windings inductors by switching ON one or more power switches from the first set of power switching devices and one or more power switches from the second set of power switching devices using PWM rectification or phase lagging type techniques.

13. The method as claimed in claim 11, further comprising:
enabling the series regulation mode when the induced voltage is higher than the required battery voltage, but lower than the voltage rating of the one or more of the first set of power switching devices and the second set of power switching devices; and
regulating the induced voltage by switching ON one or more power switches from the first set of power switching devices and one or more power switches from the second set of power switching devices such that the phases with the highest induced voltage during operation are connected to the battery and ground.

14. The method as claimed in claim 11, further comprising:
enabling the shunt regulation mode is enabled by the processing unit (101) when the induced voltage is higher than the required battery voltage as well as the voltage rating of the one or more of the first set of power switching devices and the second set of power switching devices, and
regulating the induced voltage by switching ON one or more power switches from the first set of power switching devices and one or more power switches from the second set of power switching devices using a phase advance control technique.
Dated this 27th Day of November 2020

Priyank Gupta
Agent for the Applicant
IN/PA-1454