Description:Complete specification: The following specification particularly describes the invention and the manner in which it is to be performed.

Field of the invention:
[0001] The present disclosure relates to an electric vehicle, and particularly to a charging control unit for the electric vehicle.

Background of the invention:
[0002] An electric vehicle throughout its life cycle undergoes multiple charging/discharging cycles. The charging/discharging function for an electric vehicle happens at different current requirements for various charging/discharging standards. To identify these charging/discharging standards, detect their respective current requirements and control the charging/discharging function, a charging control unit (CCU) is employed in an electric vehicle. To identify the charging/discharging standards and the current requirements, the CCU measures proximity pilot (PP) pin resistance of an Electric Vehicle Supply Equipment (EVSE)/electric load connected for the charging/discharging function respectively. In case of charging, the CCU measures proximity pilot (PP) pin resistance of the EVSE. Whereas, in the case of discharging, the CCU measures proximity pin (PP) pin resistance of the electric load.

[0003] A standard CCU comprises two microcontrollers, a standby microcontroller and a primary microcontroller, and some protection and switching elements. The problem with the present CCU architecture is that they have a high voltage drop at the protection circuit for the standby microcontroller which results in incorrect resistance measurement. This incorrect resistance measurement leads to incorrect detection of the charging/discharging standards and respective current requirements which directly impacts the operation of the CCU and the electric vehicle.

[0004] CN113442745A discloses a control pilot wake-up circuit for an in-board charger. An on-board charger (OBC) for an electric vehicle includes a charge unit, a controller, and a control pilot (CP) wake-up circuit. The charge unit is operable for receiving energy from an EVSE for charging a traction battery of the vehicle. The controller while awake can control the charge unit to charge the battery with energy from the EVSE. The CP wake-up circuit receives a control pilot (CP) signal from the EVSE, detects for a change in a current state of the CP signal while the controller is asleep, and generates a wake-up signal for waking up the controller in response to the current state of the CP signal changing to a new state. The CP wake-up circuit includes first/second detector circuits usable for detecting for a change in the current state of the CP signal to a first/second new state.

[0005] The present invention solves all the above-mentioned problems in a manner as described in the claims.

Brief description of the accompanying drawings:
[0006] An embodiment of the disclosure is described with reference to the following accompanying drawings.
[0007] Fig. 1 illustrates a first block diagram (A) of a charging control unit (CCU) for an electric vehicle, according to an embodiment of the present invention and a second block diagram (B) of a pre-existing charging control unit (CCU) architecture, already known in the art, and
[0008] Fig. 2 illustrates block diagram of a switching circuit of the charging control unit (CCU), according to an embodiment of the present invention.

Detailed description of the embodiments:
[0009] Fig. 1 illustrates a first block diagram (A) of a charging control unit (CCU) for an electric vehicle, according to an embodiment of the present invention and a second block diagram (B) of a pre-existing charging control unit (CCU) architecture, already known in the art. The first block diagram A illustrates the block circuit diagram of the charging control unit (CCU) 102 for the electric vehicle, according to the present invention. The CCU 102 comprises a primary microcontroller 104 to control at least one of a charging function and a discharging function of the electric vehicle, a standby microcontroller 106 to monitor at least one of a current charging condition and a current discharging condition and wake up the primary microcontroller 104 for at least one of the charging function and the discharging function. The standby microcontroller 106 monitors and detects a charging standard/discharging standard and the current charging condition and the current discharging condition for the detected charging standard and the detected discharging standard respectively. The primary microcontroller 104 and the standby microcontroller 106 are powered by a low voltage power source 108. The standby microcontroller 106 is powered by the low voltage power source 108 through a first power supply circuit 110, a primary protection circuit 112 connecting the first power supply circuit 110 to the standby microcontroller 106, characterized in that, a switching circuit 114 positioned after the first power supply circuit 110 and before the primary protection circuit 112, the switching circuit 114 aids the standby microcontroller 106 to measure proximity pilot (PP) pin resistance of an electric equipment 116.

[0010] A signal processing circuit 126, placed between the switching circuit 114 and the standby microcontroller 106, enables the switching circuit 114 to aid in measuring of proximity pilot (PP) pin resistance of the electric equipment 116. The signal processing circuit 126 could be a voltage divider circuit, a chopper circuit, a chopping circuit and the like. The signal processing circuit 126 and the voltage divider circuit 126 are the same and used interchangeably.

[0011] The second block diagram B of the Fig.1 illustrates the block diagram of a pre-existing charging control unit (CCU) architecture 1021, already known in the art. In the CCU 1021, a switching circuit 1141 is positioned after the primary protection circuit 112. For the CCU 1021, a high voltage drop is observed at the primary protection circuit 112. This high voltage drop at the primary protection circuit 112 reduces voltage measurement capability after the signal processing circuit 126 causing incorrect measurement of proximity pilot (PP) pin resistance of the electric equipment 116. To overcome this, the switching circuit 114 of the present invention illustrated in the first block diagram A of the Fig. 1, is placed before the primary protection circuit 112 and provided with protection capabilities against electrical faults, like short-circuit to battery (SCB) and short-circuit to ground (SCG).

Charging/Discharging conditions detected by the CCU 1021 Voltage measured after the signal processing circuit 126
Min (Volts) Max (Volts)
Open load 4.3 5.1
Plug Not Connected 3.1 3.7
S3 Open 2.5 3.1
R1: 16A Discharging 2.2 2.8
R2: 10A Charging 2.0 2.5
R3: 16A Charging 1.5 1.8
R4: 32A Charging 0.7 0.9
R5: 63A Charging 0.4 0.5
Table 1

[0012] The Table 1 illustrates voltage values measured after the signal processing circuit 126 for various charging and discharging conditions detected by the CCU 1021. It can be observed in the Table 1 for “Plug Not Connected” and “S3 Open” that there is an overlap, 3.1 Volts lies within the range of voltage measured after the signal processing circuit 126 for both the conditions. Similarly, for “S3 Open” and “R1: 16A Discharging” in Table 1 there is an overlap between the range for voltage measured after the signal processing circuit 126 for both the conditions. Further, for “R1: 16A Discharging” and “R2: 10A Charging” there is an overlap between the range for voltage measured after the signal processing circuit 126 for both the conditions. The overlap for the above conditions leads to incorrect resistance measurement by the CCU 1021 which further results in incorrect detection of the current charging condition and the current discharging condition.

Charging/Discharging conditions detected by the CCU 102
Voltage measured after the signal processing circuit 126

Min (Volts) Max (Volts)
Open load 4.8 5.1
Plug Not Connected 3.5 3.7
S3 Open 2.8 3.1
R1: 16A Discharging 2.5 2.7
R2: 10A Charging 2.2 2.4
R3: 16A Charging 1.6 1.8
R4: 32A Charging 0.8 0.9
R5: 63A Charging 0.4 0.5
Table 2

[0013] The Table 2 illustrates voltage values measured after the signal processing circuit 126 for various charging and discharging conditions detected by the CCU 102. It can be observed in the Table 2 that there is no overlap between the voltage ranges for voltage measured after the signal processing circuit 126 for various charging and discharging conditions detected by the CCU 102. The above values in the Table 1 and Table 2 are sample values and not accurate. The Table 1 and the Table 2 are provided as an example to explain the present invention in detail, but they in no manner limit the scope of this invention. The R1, R2, R3, R4, R5 represent various proximity pilot (PP) pin resistance values of the electric equipment 116.

[0014] In an embodiment of the present invention, the electric equipment 116 is at least one of an Electric Vehicle Supply Equipment (EVSE) and an electric load connector connected to a charging/discharging socket of the electric vehicle. In another embodiment of the present invention, the electric load connector is a V2L (Vehicle to Load) connector for various charging/discharging standards. The electric load is any equipment consuming electric power. In a non-limiting manner, the electric load is at least one of an electronic equipment, a household appliance, a power tool, a mobile phone, a laptop, a battery, a discharged electric vehicle, a battery and the like.

[0015] When the electric vehicle is connected to the EVSE for charging, the standby microcontroller 106 measures proximity pilot (PP) pin resistance of the EVSE using the switching circuit 114 and the signal processing circuit 126 to detect the current charging condition and wake up the primary microcontroller 104 if one of a predetermined charging conditions is met. Similarly, when the electric load is connected to the electric vehicle for discharging, the standby microcontroller 106 measures proximity pilot (PP) pin resistance of the electric load connector using the switching circuit 114 and the signal processing circuit 126 to detect the current discharging condition and wake up the primary microcontroller 104 if one of a predetermined discharging conditions is met. The standby microcontroller 106 wakes up the primary microcontroller 104 by turning ON the power supply to the primary microcontroller 104.

[0016] In an embodiment of the present invention, the standby microcontroller 106 measures proximity pilot (PP) pin resistance of the EVSE connected to the electric vehicle using the switching circuit 114 and the signal processing circuit 126 to monitor and detect the charging standard, the current charging condition and wake up the primary microcontroller 104 if the current charging condition is one of the pre-determined charging conditions for the detected charging standard. In another embodiment of the present invention, the standby microcontroller 106 measures proximity pilot (PP) pin resistance of the electric load connector connected to the electric vehicle using the switching circuit 114 and the signal processing circuit 126 to monitor and detect the discharging standard, the current discharging condition and wake up the primary microcontroller 104 if the current discharging condition is one of the pre-determined discharging conditions for the detected discharging standard. In yet another embodiment of the present invention, the monitored current charging condition is for the detected charging standard and the monitored current discharging condition is for the detected discharging standard.

[0017] The CCU 102 monitors and detects the current charging condition and wakes up the primary microcontroller 104 for CCS Type-1, CCS Type-2, NACS, GB-T, CHAdeMO, ChaoJi, and other available/future charging standards. Further, the CCU 102 monitors and detects the current discharging condition and wakes up the primary microcontroller 104 for GB-T, EVPOSSA and other available/future discharging standards. The charging information and the discharging information is exchanged between the electric vehicle and the electric equipment 116 using control signals, control pilot (CP) and proximity pilot (PP). For charging, the proximity pilot (PP) communicates whether the EVSE charging cable is connected to the electric vehicle. The EVSE for different charging standards will have different PP pin resistance for different charging current requirements. Similarly, different electric load connectors have different PP pin resistance for different discharging standards and different discharging current requirements.

[0018] In an embodiment of the present invention, the primary microcontroller 104 is powered by the low voltage power source 108 through a second power supply circuit 124. In another embodiment of the present invention, the low voltage power source 108 is a low/high voltage battery. In yet another embodiment of the present invention, the low voltage battery 108 is one of a twelve volts battery, a twenty-four volts battery, a forty-eights volts battery or the like. The standby current for the first power supply circuit 110 is less compared to the second power supply circuit 124.

[0019] Fig. 2 illustrates block diagram of the switching circuit of the CCU, according to an embodiment of the present invention. The switching circuit 114 comprises at least one switching element 202, 204 and a driver circuit 208 for protection against short-circuit to battery (SCB) and short-circuit to ground (SCG). The switching element 202, 204 is a MOSFET based circuit (other switches and semiconductor-based switches are also usable) and the driver circuit 208 is a transistor circuit (other switches and semiconductor-based switches like FET, MOSFET, IGFET, IGBT are also usable). The switching circuit 114 further comprises a pull-up resistor 206 to aid the standby microcontroller 106 to measure proximity pilot (PP) pin resistance of the electric equipment 116. The MOSFET 202 and the MOSFET 204 are back-to-back connected in opposite direction as switching elements to block reverse current flow when the MOSFETs 202, 204 are OFF. The switching elements 202, 204 and MOSFETs 202, 204 are the same and used interchangeably. The transistor circuit 208 drives the MOSFETs 202, 204 for a particular interval to aid the standby microcontroller 106 in measuring proximity pilot (PP) pin resistance of the electric equipment 116. Both the MOSFETs 202, 204 and the transistor circuit 208 provide SCB and SCG protection to the CCU 102 and its components mentioned above.

[0020] For SCB fault, the switching element 204 blocks voltage from the low voltage power source 108 and protect the standby microcontroller 106. For SCG fault, the switching element 202 will be reverse biased and protect the standby microcontroller 106.

[0021] According to the present invention, a working of the CCU 102 is explained. Whenever the electric vehicle is connected to the electric equipment 116 for the charging function or the discharging function. The standby microcontroller 106 of the CCU 102 monitors and detects the charging standard or the discharging standard and the current charging condition or the current discharging condition based on the user desired charging function or the user desired discharging function. To monitor the current charging condition or the current discharging condition, the standby microcontroller 106 measures proximity pilot (PP) pin resistance of the EVSE or the electric load connector respectively using the switching circuit 114 and the signal processing circuit 126. The driver circuit 208 of the switching circuit 114 turns ON the switching element 202, 204 for a particular interval and thus the pull-up resistor 206 comes in contact with proximity pilot (PP) pin resistance of the connected electric equipment 116. When the pull-up resistor 206 comes in contact with proximity pilot (PP) pin resistance of the EVSE or the electric load connector, a voltage value is observed after the signal processing circuit 126 which is monitored by the standby microcontroller 106. Based on the voltage value observed after the signal processing circuit 126, the standby microcontroller 106 calculates the proximity pilot (PP) pin resistance of the EVSE and the electric load connector. Further, based on the calculated proximity pilot (PP) pin resistance of the EVSE and the electric load connector, the standby microcontroller determines the current charging condition and the current discharging condition. Then finally the standby microcontroller 106 wakes up the primary microcontroller 104 if the current charging condition and the current discharging condition is one of the predetermined charging conditions and the predetermined discharging conditions for the detected charging standard and the detected discharging standard respectively. The current values for the predetermined charging conditions and the predetermined discharging conditions could be ten ampere, sixteen ampere, thirty-two ampere, sixty-three ampere, sixty-four ampere or the like.

[0022] In accordance with an embodiment of the present invention, the CCU 102 is provided with necessary signal detection, acquisition, and processing circuits. The CCU 102 is the one which comprises input interface, output interfaces having pins or ports, the memory element (not shown) such as Random Access Memory (RAM) and/or Read Only Memory (ROM), Analog-to-Digital Converter (ADC) and a Digital-to-Analog Convertor (DAC), clocks, timers, counters and at least one processor (capable of implementing machine learning) connected with each other and to other components through communication bus channels. The memory element is pre-stored with logics or instructions or programs or applications or modules/models and/or threshold values/ranges, reference values, predefined/predetermined criteria/conditions, which is/are accessed by the at least one processor as per the defined routines. The CCU 102 may also comprise communication units such as transceivers to communicate through wireless or wired means such as Global System for Mobile Communications (GSM), 3G, 4G, 5G, Wi-Fi, Bluetooth, Ethernet, serial networks, and the like. The CCU 102 is implementable in the form of System-in-Package (SiP) or System-on-Chip (SOC) or any other known types.

[0023] According to the present invention, the CCU 102 for the electric vehicle is disclosed. The present invention solves the problem of incorrect resistance measurement due to high voltage drop at the primary protection circuit 112. The above problem is solved by changing the position and the circuitry of the switching circuit 114 in the CCU 102. By moving the switching circuit 114 before the primary protection circuit 112 the complete voltage range, zero to five volts, is available after the signal processing circuit 126 for proximity pilot (PP) pin resistance measurement of the electric equipment 116. But moving the switching circuit 114 before the primary protection circuit 112 makes the switching circuit 114 vulnerable to various electric faults. Therefore, the switching circuit 114 is comprised with at least one switching element 202, 204 and the driver circuit 208 for providing protection against the short-circuit to battery (SCB) and the short-circuit to ground (SCG). Thus, the present invention provides a novel CCU 102 with minimal voltage drop at the electric equipment 116 proximity pilot (PP) pin resistance measurement circuits resulting in accurate detection of the charging/discharging standard, the current charging condition and the current discharging condition.

[0024] It should be understood that the embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modification and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims
, Claims:We claim:

1. A charging control unit (CCU) (102) for an electric vehicle, said CCU (102) comprises:
? a primary microcontroller (104) to control at least one of a charging function and a discharging function of said electric vehicle;
? a standby microcontroller (106) to monitor at least one of a current charging condition and a current discharging condition and wake up said primary microcontroller (104) for at least one of said charging function and said discharging function, said primary microcontroller (104) and said standby microcontroller (106) are powered by a low voltage power source (108), said standby microcontroller (106) is powered by said low voltage power source (108) through a first power supply circuit (110);
? a primary protection circuit (112) connecting said first power supply circuit (110) to said standby microcontroller (106), characterized in that, a switching circuit (114) positioned after said first power supply circuit (110) and before said primary protection circuit (112), said switching circuit (114) aids said standby microcontroller (106) to measure proximity pilot (PP) pin resistance of an electric equipment (116).

2. The CCU (102) as claimed in claim 1, wherein said electric equipment (116) is at least one of an Electric Vehicle Supply Equipment (EVSE) and an electric load connector connected to said electric vehicle.

3. The CCU (102) as claimed in claim 2, wherein said standby microcontroller (106) measures proximity pilot (PP) pin resistance of said Electric Vehicle Supply Equipment (EVSE) connected to said electric vehicle using said switching circuit (114) and a signal processing circuit (126) to monitor said current charging condition and wake up said primary microcontroller (104) if said current charging condition is one of a pre-determined charging conditions.

4. The CCU (102) as claimed in claim 2, wherein said standby microcontroller (106) measures proximity pilot (PP) pin resistance of said electric load connector connected to said electric vehicle using said switching circuit (114) and said signal processing circuit (126) to monitor said current discharging condition and wake up said primary microcontroller (104) if said current discharging condition is one of a pre-determined discharging conditions.

5. The CCU (102) as claimed in claim 1, wherein said switching circuit (114) comprises at least one switching element (202, 204) and a driver circuit (208) for protection against short-circuit to battery (SCB) and short-circuit to ground (SCG).

6. The CCU (102) as claimed in claim 5, wherein said switching circuit (114)
comprises a pull-up resistor (206) to aid said standby microcontroller (106) to measure proximity pilot (PP) pin resistance of said electric equipment (116).

7. The CCU (102) as claimed in claim 5, wherein said switching element (202, 204) is a MOSFET and said driver circuit (208) is a transistor circuit.

8. The CCU (102) as claimed in claim 1, wherein said current charging condition is for a charging standard and said current discharging condition is for a discharging standard.

9. The CCU (102) as claimed in claim 1, wherein said primary microcontroller (104) is powered by said low voltage power source (108) through a second power supply circuit (124).

10. The CCU (102) as claimed in claim 1, wherein said low voltage power source (108) is a low voltage battery.