Charging control method and charging control device for electric vehicle

Abstract

The present invention relates to a charging control method and a charging control device for an electric vehicle, the method boosting a charging voltage using a motor and an inverter and including the steps of determining whether a current imbalance control is normally operated based on a current input to a three-phase input of the inverter from the motor during charging; when the current imbalance control is normally operated, determining whether a current sensor is deteriorated based on a result of temperature sensing inside the inverter; and when the determined result is that the current sensor is detected to be deteriorated, adjusting a scale of the current sensor to maintain charging.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2020-0175697, filed on December 15, 2020, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the charging of electric vehicles, and more specifically, to a charging control method and charging control device for electric vehicles that boosts the charging voltage through a motor and an inverter. When current sensor degradation is detected in the electric vehicle, the method optimizes current imbalance control by adjusting the sensor scale to maintain charging. Background Technology

[0004] A high-voltage battery installed in an electric vehicle is a high-output, high-capacity battery system used to drive a drive motor to power the electric vehicle.

[0005] Figure 1 (Related Technology) illustrates various electric vehicle charging methods utilizing high-voltage batteries.

[0006] like Figure 1 As shown in the attached figure 1a, the output energy of the high-voltage battery is converted into DC / AC by an inverter and then transmitted to the drive motor to drive the electric vehicle.

[0007] The methods for charging high-voltage batteries can be broadly divided into slow charging methods and fast charging methods.

[0008] like Figure 1 As shown in Figure 1b, the fast charging method utilizes direct current converted from external charging infrastructure to directly charge the battery at high power through Electric Vehicle Supply Equipment (EVSE). Currently, fast charging infrastructures such as 50kW-500V / 100A, 100kW-500V / 200A, 200kW-500V / 400A, and 400kW-1000V / 400A are available both domestically and internationally.

[0009] In the case of an 800V-class electric vehicle battery system, using a 1000V-class fast charging infrastructure without issue allows for normal fast charging. However, when using a 500V-class fast charging infrastructure, the output voltage of the fast charging equipment only reaches up to 500V (controlled to a maximum of 450V for margin), thus requiring a voltage boosting process. Traditional electric vehicles utilize the motor's coils and the inverter's power conversion switch to boost the voltage, such as... Figure 1As shown by reference numeral 1c in the attached figure. Therefore, a method for fast charging in a 500 / 1000V infrastructure can be provided by controlling the output of the motor and inverter.

[0010] The main control unit (MCU) of a conventional power converter used for boost charging provides internal control of current imbalance. The MCU recalculates the actual current based on the voltage sensed by the current sensor and a preset current sensor ratio, then executes feedback control to update the duty cycle of each phase according to the current identified by the MCU. However, under deterioration conditions, the actual current is incorrectly identified from the start of operation, making it difficult to control the actual phase current imbalance. Summary of the Invention

[0011] One aspect of the present invention provides a charging control method and a charging control device for electric vehicles.

[0012] Another aspect of the present invention provides a charging control method and charging control device for electric vehicles. The method can prevent the temperature of the IGBT from rising further due to phase current imbalance, thereby preventing output limitation or charging interruption caused by device overheating.

[0013] Another aspect of the present invention provides a charging control method and charging control device for electric vehicles. The method can use the difference in the temperature sensing values ​​of each phase's IGBT to determine the difference between the actual current of each phase's current sensor and the current recognized by the MCU to determine the degradation of the current sensor of each phase. When degradation is determined, the current sensor ratio is changed in real time to minimize the difference between the actual current and the current recognized by the MCU.

[0014] The technical problems to be solved by the present invention are not limited to those described above. Those skilled in the art will clearly understand from the following description any other technical problems not mentioned herein.

[0015] According to one aspect of the present invention, a charging control method for an electric vehicle that uses a motor and an inverter to boost the charging voltage includes the following steps: during charging, determining whether current imbalance control is operating normally based on the current from the motor input to the three-phase input terminal of the inverter; when the current imbalance control is operating normally, determining whether the current sensor is degraded based on the result of temperature sensing inside the inverter; when the determination result is that the current sensor is detected to be degraded, adjusting the ratio of the current sensor to maintain charging.

[0016] In an embodiment, the current sensor can include three-phase current sensors operating as a U-phase current sensor, a V-phase current sensor, and a W-phase current sensor, and the current imbalance control can be performed based on three-phase currents varied in proportion to the adjusted current sensor.

[0017] In an embodiment, determining whether the current sensor is deteriorated can be determined based on a difference in temperature sensing values of IGBTs (Insulated Gate Bipolar Transistors) of each phase.

[0018] In an embodiment, when the current imbalance control is normally operated, determining whether the current sensor is deteriorated can include comparing the difference in temperature sensing values of the IGBTs of each phase with a predetermined reference value to identify the deteriorated current sensor and a deterioration situation.

[0019] In an embodiment, the proportion of the current sensor can be adjusted up or down based on the identified deterioration situation.

[0020] In an embodiment, each phase can include two IGBTs, and the reference value can be applied differently for the two IGBTs.

[0021] In an embodiment, the reference value of the two IGBTs can have different signs according to the deterioration situation.

[0022] In an embodiment, the reference value can be determined considering at least one of a load condition, a temperature sensor position deviation, a temperature sensing error, or a current sensor sensing error.

[0023] In an embodiment, the proportion adjustment of the current sensor can be performed for a phase corresponding to the deteriorated current sensor.

[0024] In an embodiment, the method can further include, when the result of the determination is that the current sensor deterioration is not detected, determining that the current sensor is normally operated and maintaining charging.

[0025] According to another aspect of the present application, a charging control apparatus of an electric vehicle that boosts a charging voltage by using a motor and an inverter includes a sensing apparatus that senses an internal temperature of the inverter and a current input to three-phase input terminals of the inverter from the motor, a deterioration determiner that determines whether a current imbalance control is normally operated based on a current sensing result during charging, and when the current imbalance control is normally operated, determines whether a current sensor is deteriorated based on a temperature sensing result, and a sensor proportion optimizer that adjusts a proportion of the current sensor when the result of the determination is that the current sensor deterioration is detected.

[0026] In an embodiment, the current sensor can include three-phase current sensors operating as a U-phase current sensor, a V-phase current sensor, and a W-phase current sensor, and the charging control device of the electric vehicle can further include a three-phase current imbalance controller configured to perform current imbalance control based on three-phase currents varied in proportion to the adjusted current sensor.

[0027] In an embodiment, the deterioration determiner can determine whether the current sensor is deteriorated based on a difference in temperature sensing values of the insulated gate bipolar transistors of each phase received from the sensing device.

[0028] In an embodiment, when the current imbalance control is normally operated, the deterioration determiner can compare the difference in temperature sensing values of the IGBTs of each phase with a predetermined reference value to identify the current sensor in which deterioration occurs and a deterioration situation.

[0029] In an embodiment, the sensor proportion optimizer can adjust the proportions of the current sensors up or down based on the identified deterioration situation.

[0030] In an embodiment, each phase can include two IGBTs, and the reference value can be differently applied to the two IGBTs.

[0031] In an embodiment, the reference values of the two IGBTs can have different signs based on the deterioration situation.

[0032] In an embodiment, the reference value can be determined considering at least one of a load condition, a temperature sensor position deviation, a temperature sensing error, or a current sensor sensing error.

[0033] In an embodiment, the sensor proportion optimizer can adjust the proportions of the current sensors with respect to the phase corresponding to the current sensor in which deterioration occurs.

[0034] In an embodiment, when the result of the determination is that it is detected that the current sensor is not deteriorated, it can be determined that the current sensor is normally operated to maintain charging. BRIEF DESCRIPTION OF DRAWINGS

[0035] The above and other objects, features and advantages of the present application will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0036] Figure 1 (Related Art) is a schematic diagram showing various electric vehicle charging methods using a high-voltage battery;

[0037] Figure 2 is a circuit structure diagram of a power conversion device for charging an electric vehicle according to an embodiment of the present application;

[0038] Figures 3A-3D is a schematic diagram describing a power conversion process when an electric vehicle according to an embodiment of the present application is charged;

[0039] Figure 4 is a schematic diagram describing a current control method applied when a conventional electric vehicle is charged;

[0040] Figure 5 is a schematic diagram describing a case where a power conversion device deteriorates;

[0041] Figure 6 is a block diagram describing a configuration of an electric vehicle charging control device according to an embodiment of the present application;

[0042] Figure 7 is a flowchart describing a charging control method in an electric vehicle charging control device according to an exemplary embodiment of the present application, in which IGBT1 indicates a top IGBT device per phase, IGBT2 indicates a bottom IGBT device per phase, Tu1 indicates a temperature of the IGBT1 device of the U phase, Tu2 indicates a temperature of the IGBT2 device of the U phase, Tv1 indicates a temperature of the IGBT1 device of the V phase, Tv2 indicates a temperature of the IGBT2 device of the V phase, Tw1 indicates a temperature of the IGBT1 device of the W phase, and Tw2 indicates a temperature of the IGBT2 device of the W phase;

[0043] Figure 8 is a flowchart describing a charging control method in an electric vehicle charging control device according to another embodiment of the present application, in which IGBT1 indicates a top IGBT device per phase, IGBT2 indicates a bottom IGBT device per phase, Tu1 indicates a temperature of the IGBT1 device of the U phase, Tu2 indicates a temperature of the IGBT2 device of the U phase, Tv1 indicates a temperature of the IGBT1 device of the V phase, Tv2 indicates a temperature of the IGBT2 device of the V phase, Tw1 indicates a temperature of the IGBT1 device of the W phase, and Tw2 indicates a temperature of the IGBT2 device of the W phase; and

[0044] Figure 9 is a flowchart describing a charging control method in an electric vehicle charging control device according to another embodiment of the present application. DETAILED DESCRIPTION

[0045] It should be understood that the terms "vehicle" or "vehicular" or other similar terms used herein generally include motor vehicles, such as passenger vehicles including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, passenger vehicles including various boats, ships, aircraft, etc., and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuel from non- fossil sources). As referred to herein, a hybrid vehicle is a vehicle having two or more sources of power, such as both gasoline power and electric power.

[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Throughout this specification, the word "comprise," or variations such as "comprises" or "comprising," will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. In addition, the terms "unit", "device", "part", and "module" described in the specification mean a unit for processing at least one function and operation, and can be implemented by hardware components or software components, and combinations thereof.

[0047] Further, the control logic of the present application can be implemented as non-transitory computer readable media on a computer readable medium, which contains executable program instructions executed by a processor, a controller, etc. Examples of the computer readable medium include, but are not limited to, ROM, RAM, compact disc (CD)-ROM, tape, floppy disk, flash memory, smart card, and optical data storage device. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable medium is stored and executed in a distributed fashion, e.g., as being stored and executed in the remote information processing server or the controller area network (CAN).

[0048] Some embodiments of the present application will be described below in detail with reference to the accompanying drawings. When adding reference numerals to components in each drawing, it should be noted that the same or equivalent components are denoted by the same reference numerals even though they are shown in other drawings. Also, in describing embodiments of the present application, detailed description of known related configurations or functions incorporated herein will be omitted when it is determined that such a detailed description can unnecessarily obscure the understanding of embodiments of the present application.

[0049] In describing components of embodiments according to the present application, terms such as first, second, A, B, (a), (b), etc. can be used. These terms are used only to distinguish one component from another component, and the terms do not limit the nature, sequence, or order of the components. Unless otherwise defined, all terms used herein, including technical terms and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined in the present application.

[0050] Hereinafter, reference will be made to Figures 2-9 Embodiments of the present application are described in detail.

[0051] Figure 2 is a circuit configuration diagram of a power conversion device for charging an electric vehicle according to an embodiment of the present application.

[0052] Referring to Figure 2 The power conversion device 200 can include a fast EVSE 210, an inverter neutral side relay 220, a drive motor 230, a power conversion switch 240, a current sensor 250, a temperature sensor 260, and a main controller 270.

[0053] The fast EVSE 210 can receive vehicle information (e.g., whether the vehicle is stopped, whether the charging plug is engaged, etc.) by communicating with an internal controller of the vehicle, and can transmit EVSE information (e.g., whether the EVSE relay is engaged, etc.) to the internal controller of the vehicle.

[0054] The inverter neutral side relay 220 can control electrical connection between the fast EVSE 210 and the drive motor 230 / inverter before a plurality of charging starts.

[0055] The drive motor 230 can repeatedly store and transmit electric power during switching of an Insulated Gate Bipolar Transistor (IGBT) as a motor inductance component.

[0056] The power conversion switch 240 can control the flow of power to a high-voltage battery by performing on / off control of a plurality of IGBTs provided. As an example, the power conversion switch 240 can include a total of six IGBTs.

[0057] The current sensor 250 can sense the intensity of three-phase (U-phase / V-phase / W-phase) current applied from the drive motor 230 to the power conversion switch 240. For example, the current sensor 250 can be a Hall-type current sensor.

[0058] The temperature sensor 260 can be provided in the IGBTs of the power conversion switch 240 to sense the temperature of the IGBTs. For example, the temperature sensor 260 can be provided in each IGBT. For example, the temperature sensor 260 can be a chip-type temperature sensor.

[0059] The main controller 270 can perform pulse width modulation signal control, fault diagnosis, cooperative control with other controllers, etc. required for the operation of the inverter based on the sensed values such as current and temperature.

[0060] Figures 3A-3D is a schematic diagram describing a power conversion process when an electric vehicle according to an embodiment of the present application is charged.

[0061] Referring to Figure 3A When the electric vehicle is charged, the power conversion device 200 can perform PWM control to alternately switch the IGBT 1 and the IGBT 2 of each phase (U, V, W) of the inverter, thereby performing step-up.

[0062] Figure 3A Reference numeral 310 of is a current when the IGBT 1 is off and the IGBT 2 is on, and reference numeral 320 is a current when the IGBT 2 is off and the IGBT 1 is on.

[0063] Vin is a voltage of the neutral point of the inverter (i.e., the EVSE output side), and Vout is a voltage of the battery side.

[0064] The energy applied from the external power source to the inductor is stored in the inductor and then transmitted to the battery.

[0065] Figure 3B The variation of the phase current of the motor according to the on / off of the IGBT 2 is shown.

[0066] In this case, the step-up ratio (Vout / Vin) is determined by the duty ratio of the IGBT 2, which is the ratio of the voltage Vin applied from the external power source to the inverter output voltage Vout.

[0067] In this case, the duty ratio is the on (ON) time "A" of each switching period "T", which is the sum of the on time "A" and the off (OFF) time "B".

[0068] As Figure 3C shown, the power conversion device 200 can perform three-phase interleaved control with one-third "A / 3" of the on time "A" to reduce the ripple of the input current.

[0069] The output of the inverter can be controlled by the U-phase duty ratio, the V-phase duty ratio, and the W-phase duty ratio.

[0070] As shown in reference numeral 330, the power conversion device 200 can minimize the ripple by summing up and outputting the current of each phase per "A / 3".

[0071] In Figure 3C In an embodiment of the disclosure, the summing period of the current of each phase for minimizing the ripple of the inverter output current is "A / 3", but this is only one embodiment, and the summing period can be set to be shorter or longer according to the design of those skilled in the art.

[0072] Referring to Figure 3D , the IGBT temperature increases as the external air temperature, the cooling water temperature, and the amount of power conversion loss increase.

[0073] As the external temperature increases, the natural heat dissipation speed of the cooling water heated by the heat generated by the IGBT slows down, so the device temperature increases during charging.

[0074] As the cooling water temperature increases, the speed at which the heat generated by the IGBT escapes slows down, so the device temperature increases during charging.

[0075] The amount of power conversion loss can include conduction loss and switching loss. The conduction loss is proportional to the amount of current at the time of conduction and the conduction resistance, and the switching loss is proportional to the amount of current, voltage, and switching frequency at the time of switching. That is, as the current flowing through the IGBT increases, the IGBT temperature increases.

[0076] Figure 4 is a schematic diagram illustrating a conventional current control method applied when a conventional electric vehicle is charged.

[0077] The conventional power conversion device converts three-phase (U, V, W) currents sensed through a Hall-type current sensor into voltage values proportional to the respective currents and transmits the converted voltage values to an MCU.

[0078] The power conversion device converts the received voltage values by applying the ratio "α" of the current sensor stored in the ROM inside the MCU and then re-converts them into current values for controlling the phase current feedback in the MCU.

[0079] In this case, the ratio "α" of the current sensor is calculated by dividing the voltage received by the MCU by the voltage recognized by the MCU, and the three-phase general current sensor ratio can be applied when converting the current.

[0080] The power conversion device performs inter-phase current imbalance control through closed-loop control, and applies the changed individual duty ratios Du, Dv, Dw of each phase to the IGBT U phase / IGBT V phase / IGBT W phase of the power conversion switch.

[0081] The three-phase current imbalance controller performs feedback control on the sensed values of Iu, Iv and Iw by using "D" and "Iin", and generates individual duty ratios Du, Dv and Dw such that Iin = Iu + Iv + Iw, and Iu = Iv = Iw.

[0082] In this case, in order to maintain neutral point voltage control, the duty ratio "D" maintains the average value of individual duty ratios Du, Dv and Dw of each phase, as shown in the following equation.

[0083] D = Avg(Du + Dv + Dw)

[0084] In this case, Iin is the command current input to the neutral point of the inverter, Iu, Iv and Iw are three-phase sensed currents, and 'D' is a duty ratio value common to three phases generated for neutral point voltage control.

[0085] Figure 5 is a diagram describing a case of deterioration of the power conversion device.

[0086] Referring to reference numeral 510, during charging, when the current sensor of one phase deteriorates, the sensed voltage (i.e., the sensed voltage) can be measured as higher or lower with respect to the current actually flowing in the corresponding phase (i.e., the actual current). Case 1 is a case where the sensed voltage is higher than the actual current, and Case 2 is a case where the sensed voltage is lower than the actual current.

[0087] Reference numeral 520 is a table summarizing the main change control and the measured value change of each deterioration case.

[0088] Due to the difference between the current recognized by the MCU and the actual current, the MCU 270 can recognize the currents of the three phases as being equally controlled by the imbalance control in the MCU 270. However, under normal control, the U-phase actual current can decrease in Case 1 and can increase in Case 2. In this case, since the V-phase current Iv and the W-phase current Iw are the same even when the input current Iin deteriorates, the remaining phase currents increase in Case 1 and decrease in Case 2.

[0089] Even if the V-phase or (and) W-phase current sensor deteriorates, the phase current of the corresponding deteriorated current sensor decreases in Case 1 and increases in Case 2, and the remaining phase currents increase in Case 1 and decrease in Case 2.

[0090] Since the conduction loss and the switching loss increase as the magnitude of the actual current flowing through the IGBT increases, the temperature of the IGBT decreases in Case 1 and increases in Case 2 compared to the normal case, and the temperature of the IGBT of the V-phase and the W-phase increases in Case 1 and decreases in Case 2 compared to the normal case. When the internal temperature increases, the MCU 270 sets an output limit higher than a certain temperature to perform over-temperature protection or stops charging by PWM OFF. For example, when the temperature of the external air or the cooling water is high or the charging conditions are poor (e.g., charging is performed with excessively high current), the temperature of the IGBT further increases due to phase current imbalance caused by deterioration of the current sensor, and thus the probability of output limitation or interruption of charging can increase.

[0091] As described above, in the conventional charging system, the MCU has a current imbalance controller inside, but the controller recalculates the actual current by the current sensor ratio based on the voltage sensed by the normal current sensor, and then updates the duty of each phase by performing feedback control to follow the current recognized by the MCU. However, since the actual current is incorrectly recognized from the beginning when deterioration occurs, there is a problem that the actual phase current imbalance cannot be controlled.

[0092] Therefore, in order to achieve the purpose of controlling imbalance based on the actual current in the case of deterioration, and to prevent the IGBT temperature from additionally increasing due to phase current imbalance even in the worst charging conditions in which the temperature of the external air or the cooling water is high or large current charging is performed, a charging system capable of preventing output limitation or interruption of charging due to device over-temperature is required.

[0093] Figure 6 is a block diagram describing the configuration of an electric vehicle charging control device according to an embodiment of the present application.

[0094] Hereinafter, for convenience of description, the electric vehicle charging control device 600 will be simply referred to as "device 600" and described.

[0095] The device 600 according to the present embodiment can be implemented on the MCU 270 of the above-described Figure 2 , but this is only one embodiment, and the device 600 of the present embodiment can be implemented as a device separate from the MCU 270 and can intercommunicate with the MCU 270.

[0096] Referring to Figure 6 , the device 600 can include a sensing device 610, an operating device 620, and a controller 630.

[0097] The sensing device 610 can be configured to include a temperature sensor 611 and a current sensor 612.

[0098] The temperature sensor 611 can receive a voltage of an IGBT temperature sensor output, and can convert the received voltage value into an IGBT temperature value by using a temperature / voltage conversion table stored in advance.

[0099] The current sensor 612 can receive a voltage of a Hall-type current sensor output, and convert the received voltage value into a current value by using a current sensor ratio.

[0100] The operation device 620 can include a deterioration determiner 621 and a sensor ratio optimizer 622.

[0101] During normal operation of the current imbalance controller, the deterioration determiner 621 can compare the temperature of the IGBT of each phase received from the temperature sensor 611. In this case, the deterioration determiner 621 can determine whether the current sensor is deteriorated by comparing the temperature difference between the phases with a preset reference value, and can identify the type of phase in which the current sensor is deteriorated and the deterioration situation. For example, the deterioration determiner 621 can measure the temperature difference of IGBT 1 and IGBT 2 with respect to the U phase, the V phase, and the W phase. For the robustness of logic, only when the temperature difference between the phases of both IGBT 1 and IGBT 2 deviates from a predetermined reference value, the deterioration determiner 621 can determine that the current sensor deterioration has occurred.

[0102] The sensor ratio optimizer 622 can change the current sensor ratio in units of a certain value based on the deterioration phase type information and / or the deterioration situation received from the deterioration determiner 621, and can transmit the changed ratio value to the current sensor 612.

[0103] The controller 630 can include a three-phase current imbalance controller 631. The three-phase current imbalance controller 631 according to the present embodiment can be implemented in the same manner as the conventional structure.

[0104] The three-phase current imbalance controller 631 can receive three-phase current values from the sensor 610, and can update the existing duty ratio of each phase by using feedback control of the command of the neutral point current, thereby controlling the sensed current value to be balanced.

[0105] Figure 7 FIG. 1 is a flowchart describing a charging control method in an electric vehicle charging control device according to an exemplary embodiment of the present application.

[0106] Specifically, Figure 7 FIG. 2 is a schematic diagram for describing Figure 6 FIG. 3 is a schematic diagram of deterioration determination logic in case 1 of the deterioration determiner 621.

[0107] Referring to Figure 7When charging begins, device 600 can receive a command for neutral point voltage Vin (S701).

[0108] Device 600 can determine a common duty cycle "D" based on the instruction of neutral point voltage Vin, and can generate a PWM signal corresponding to the determined common duty cycle and provide it to the inverter (S702 and S703).

[0109] Device 600 can perform three-phase (U-phase, V-phase and W-phase) current sensing (S704 and S705) based on the command of neutral point current Iin.

[0110] The device 600 can compare the difference between the three-phase current sensing values ​​Iu, Iv and Iw with a predetermined reference value “B” (S706).

[0111] When the comparison result shows that the difference between the three-phase current sensing values ​​is less than the reference value 'B', the device 600 can perform normal current imbalance control operation (S707).

[0112] Subsequently, device 600 can initiate a degradation determination procedure (S708).

[0113] The following operations can be performed by Figure 6 The degradation determiner 621 performs the operation.

[0114] Device 600 can perform temperature sensing of three-phase IGBT 1 and IGBT 2 (S709). In the following text, the temperature of the U-phase IGBT 1 device is named "Tu1", the temperature of the U-phase IGBT 2 device is named "Tu2", the temperature of the V-phase IGBT 1 device is named "Tv1", the temperature of the V-phase IGBT 2 device is named "Tv2", the temperature of the W-phase IGBT 1 device is named "Tw1", and the temperature of the W-phase IGBT 2 device is named "Tw2", and these will be described.

[0115] The device 600 can determine whether the difference between Tu1 and Tv1 and the difference between Tu1 and Tw1 are both less than a first threshold "-C" (S710).

[0116] When the result determined in S710 is that both differences are less than the first threshold, the device 600 can determine whether the difference between Tu2 and Tv2 and the difference between Tu2 and Tw2 are both less than the second threshold "-D" (S711).

[0117] When the result determined in S711 is that both differences are less than the second threshold, the device 600 can determine that the U-phase current sensor is degraded and can adjust the ratio of the U-phase current sensor (S711 to S713).

[0118] When the result of the determination in S710 is that both of the difference values are not less than the first threshold value, the device 600 can determine whether both of the difference between Tv1 and Tu1 and the difference between Tv1 and Tw1 are less than the first threshold value "-C" (S714).

[0119] When the result of the determination in S714 is that both of the difference values are less than the first threshold value, the device 600 can determine whether both of the difference between Tv2 and Tu2 and the difference between Tv2 and Tw2 are less than the second threshold value "-D" (S715).

[0120] When the result of the determination in S715 is that both of the difference values are less than the second threshold value, the device 600 can determine that the V-phase current sensor is deteriorated, and can adjust the scale of the V-phase current sensor (S716 and S717).

[0121] When the result of the determination in S714 is that both of the difference values are not less than the first threshold value, the device 600 can determine whether both of the difference between Tw1 and Tu1 and the difference between Tw1 and Tv1 are less than the first threshold value "-C" (S718).

[0122] When the result of the determination in S718 is that both of the difference values are less than the first threshold value, the device 600 can determine whether both of the difference between Tw2 and Tu2 and the difference between Tw2 and Tv2 are less than the second threshold value "-D" (S719).

[0123] When the result of the determination in S719 is that both of the difference values are less than the second threshold value, the device 600 can determine that the W-phase current sensor is deteriorated, and can adjust the scale of the W-phase current sensor (S720 and S721).

[0124] When the result of the determination in S718 is that both of the difference values are not less than the first threshold value, the device 600 can determine that the current sensor is not deteriorated (S722).

[0125] When the result of the determination in S711, S715, or S719 is that the difference values are not less than the second threshold value, the device 600 can perform S709.

[0126] In the above-described embodiment, the threshold values "-C" and "-D" for determining whether the current sensor is deteriorated can be determined in consideration of a load condition, a temperature sensor position deviation, a sensing error, and a current sensor sensing error, etc. and in consideration of logic robustness.

[0127] Figure 8 is a flowchart describing a charging control method in an electric vehicle charging control device according to another embodiment of the present application.

[0128] Specifically, Figure 8is a schematic view of the deterioration determination logic for case 2 in the deterioration determiner 621 for describing Figure 6

[0129] Referring to Figure 8 When the charging is started, the device 600 can receive an instruction of the neutral point voltage Vin (S801).

[0130] The device 600 can determine a common duty ratio "D" based on the instruction of the neutral point voltage Vin, generate a PWM signal corresponding to the determined common duty ratio, and provide the same to the inverter (S802 and S803).

[0131] The device 600 can perform three-phase (U-phase, V-phase, and W-phase) current sensing based on the instruction of the neutral point current Iin (S804 and S805).

[0132] The device 600 can compare a difference between the three-phase current sensing values Iu, Iv, and Iw with a predetermined reference value "B" (S806).

[0133] When the result of the comparison is that the differences between the three-phase current sensing values are all less than the reference value "B", the device 600 can perform a normal current imbalance control operation (S807).

[0134] Thereafter, the device 600 can start a deterioration determination procedure (S808).

[0135] The following operations can be operations performed by the deterioration determiner 621 of the deterioration determination apparatus 600. Figure 6

[0136] The device 600 can perform temperature sensing of the IGBTs 1 and 2 of the three phases (S809). Hereinafter, the temperature of the U-phase IGBT 1 device is named "Tu1", the temperature of the U-phase IGBT 2 device is named "Tu2", the temperature of the V-phase IGBT 1 device is named "Tv1", the temperature of the V-phase IGBT 2 device is named "Tv2", the temperature of the W-phase IGBT 1 device is named "Tw1", the temperature of the W-phase IGBT 2 device is named "Tw2", and will be described.

[0137] The device 600 can determine whether both of a difference between Tu1 and Tv1 and a difference between Tu1 and Tw1 are greater than a first threshold value "C" (S810).

[0138] When the result determined in S810 is that both of the two differences are greater than the first threshold value "C", the device 600 can determine whether both of a difference between Tu2 and Tv2 and a difference between Tu2 and Tw2 are greater than a second threshold value "D" (S811).

[0139] ​​When the result of the determination in S811 is that both of the differences are greater than the second threshold "D", the device 600 can determine that the U-phase current sensor is deteriorated, and can adjust the scale of the U-phase current sensor (S812 and S813).

[0140] When the result of the determination in S810 is that both of the differences are not greater than the first threshold "C", the device 600 can determine whether both of the difference between Tv1 and Tu1 and the difference between Tv1 and Tw1 are greater than the first threshold "C" (S814).

[0141] When the result of the determination in S814 is that both of the differences are greater than the first threshold "C", the device 600 can determine whether both of the difference between Tv2 and Tu2 and the difference between Tv2 and Tw2 are greater than the second threshold "D" (S815).

[0142] When the result of the determination in S815 is that both of the differences are greater than the second threshold "D", the device 600 can determine that the V-phase current sensor is deteriorated, and can adjust the scale of the V-phase current sensor (S816 and S817).

[0143] When the result of the determination in S814 is that both of the differences are not greater than the first threshold "C", the device 600 can determine whether both of the difference between Tw1 and Tu1 and the difference between Tw1 and Tv1 are greater than the first threshold "C" (S818).

[0144] When the result of the determination in S818 is that both of the differences are greater than the first threshold "C", the device 600 can determine whether both of the difference between Tw2 and Tu2 and the difference between Tw2 and Tv2 are greater than the second threshold "D" (S819).

[0145] When the result of the determination in S819 is that both of the differences are greater than the second threshold "D", the device 600 can determine that the W-phase current sensor is deteriorated, and can adjust the scale of the W-phase current sensor (S820 and S821).

[0146] When the result of the determination in S818 is that both of the differences are not greater than the first threshold "C", the device 600 can determine that the current sensor is not deteriorated (S822).

[0147] When the result of the determination in S811, S815, or S819 is that the differences are not all greater than the second threshold, the device 600 can perform S809.

[0148] In the above-described embodiments, the thresholds "C" and "D" for determining whether the current sensor is deteriorated can be determined in consideration of a load condition, a temperature sensor position deviation, a sensing error, and a current sensor sensing error, etc. and in consideration of logic robustness.

[0149] In Figures 7-8 an embodiment of the present application, in case of deterioration case 1 / 2, since the case where the temperature is lower than that of the other phase is case 1 (MCU recognizes that the current is high due to the MCU sensing voltage rise), and the case where the temperature is higher than that of the other phase is case 2, it can be determined whether deterioration occurs by comparing the temperature difference with the other phase and the threshold value of different signs.

[0150] In Figures 7-8 an embodiment of the present application, when it is determined that the sensor is normal even when deterioration re-determination is performed, the device 600 can end the deterioration determination logic, and can maintain the charging operation.

[0151] Figure 9 is a flowchart describing a charging control method in an electric vehicle charging control device according to another embodiment of the present application.

[0152] Specifically, Figure 9 is a schematic diagram for describing a current sensor proportional control operation in the sensor proportional optimizer 622 of Figure 6

[0153] Referring to Figure 9 , the device 600 can receive the result of the current sensor deterioration determination from the deterioration determiner 621 (S901). In this case, the result of the current sensor deterioration determination can include deterioration phase type information and / or deterioration type information, i.e., deterioration case recognition information. In this case, the deterioration determiner 621 can determine whether deterioration occurs when the three-phase current imbalance controller 631 is in a normal operation condition. The deterioration determiner 621 can determine whether each phase is deteriorated by sensing the temperature of the top IGBT and the bottom IGBT (i.e., IGBT 1 and IGBT 2) of each phase, and then comparing the temperature between the top IGBTs and the temperature between the bottom IGBTs. Since such an operation effectively reflects the case where the RMS (Root Mean Square) current value of one cycle of the top IGBT and the bottom IGBT in one phase varies depending on the duty ratio, it is possible to more accurately determine whether deterioration exists. In addition, in order to secure the robustness of the logic from the influence of measurement errors due to sensing noise, etc., deterioration of the current sensor is determined only when the sensed temperature difference with the other phase is greater than or equal to a certain value for both the top and the bottom, and thus it is possible to secure the reliability of determining whether deterioration occurs.

[0154] The device 600 can determine whether the deterioration type is case 1 based on the received deterioration determination result of the current sensor (S902).

[0155] When the result of the determination of S902 is that the deterioration type is case 1, the device 600 can adjust the current sensor proportion "a" upward by a certain level "T" (S903).​

[0156] The device 600 can perform three-phase (U-phase, V-phase, and W-phase) current sensing (S904).

[0157] The device 600 can compare the difference between the three-phase current sensing values Iu, Iv, and Iw with a predetermined reference value "B" (S905).

[0158] When the result of the comparison is that the difference between the three-phase current sensing values is less than the reference value "B", the device 600 can perform a normal current imbalance control operation (S906).

[0159] Thereafter, the device 600 can perform a deterioration determination procedure (S907).

[0160] When the deterioration type is not Case 1, i.e., is Case 2, based on the received current sensor deterioration determination result in S902, the device 600 can adjust the current sensor ratio "a" downward by a certain level "T" (S908). Thereafter, the device 600 can perform S904 described above.

[0161] Accordingly, the steps of methods or algorithms described in connection with the embodiments disclosed herein can be effected by hardware embodied in a processor, software modules executed by a processor, or combinations thereof. The software modules can be stored on a storage medium, such as a RAM, a flash memory, a ROM, an EPROM, an EEPROM, a register, a hard disk, a removable disk, and a CD-ROM.

[0162] The storage medium is coupled to the processor, and the processor can read information from and write information to the storage medium. Alternatively, the storage medium can be integrated into the processor. The processor and the storage medium can be existing in an application specific integrated circuit (ASIC). The ASIC can exist in the user terminal. Alternatively, the processor and the storage medium can exist as separate components within the user terminal.

[0163] According to embodiments, the present application can provide a charging control method and a charging control device of an electric vehicle.

[0164] Further, according to embodiments, the present application can provide a charging control method and a charging control device of an electric vehicle, which can prevent an output restriction or a charging interruption due to a device over-temperature in advance by preventing a further temperature rise of an IGBT due to a phase current imbalance.

[0165] Further, according to embodiments, the present application can provide an electric vehicle charging control method and charging control device, which can determine the deterioration of a current sensor of each phase using a difference value of an IGBT temperature sensing value of each phase, and dynamically change a current sensor ratio when the deterioration is determined, thereby minimizing a difference value between an actual current and a current recognized by an MCU.

[0166] Further, according to embodiments, the present application can provide an electric vehicle charging control method and charging control device, which can perform imbalance control based on an actual current by optimizing a current sensor ratio according to deterioration and a deterioration degree, reduce a maximum operating temperature of an IGBT device, and thereby improve the durability of the device.

[0167] Further, according to embodiments, the present application can prevent an additional increase in the temperature of an IGBT due to current imbalance between phases, and prevent output limitation or charging interruption due to overheating, even in adverse conditions such as high temperature of external air and / or coolant or large current charging, thereby minimizing consumer complaints during charging.

[0168] Further, according to embodiments, the present application can increase output through the same IGBT device using a temperature margin obtained by preventing an additional increase in the temperature of an IGBT.

[0169] Further, according to embodiments, the present application can provide a safer and better power conversion device by adding deterioration determination logic and current sensor ratio optimization logic, without increasing costs due to additional hardware.

[0170] Further, various effects directly or indirectly recognized through the present document can be provided.

[0171] The above description is merely an explanation of the technical idea of the present application, and those of ordinary skill in the art to which the present application pertains will be able to make various modifications and changes without departing from the essential characteristics of the present application. Therefore, the embodiments disclosed in the present application are intended to explain the technical idea of the present application, not to limit the technical idea, and the scope of the technical idea of the present application is not limited by these embodiments. The scope of protection of the present application should be interpreted by the appended claims, and all technical ideas within the equivalent scope thereof should be understood to be included in the scope of the present application.

Claims

1. A charging control method of an electric vehicle that boosts a charging voltage using a motor and an inverter, the charging control method comprising: determining, by a deterioration determiner, whether a current imbalance control is normally operated based on a current input to a three-phase input of the inverter from the motor during charging; when the current imbalance control is normally operated, determining, by the deterioration determiner, whether a current sensor is deteriorated based on a result of sensing an internal temperature of the inverter; when a result of the determination is that the current sensor is detected to be deteriorated, adjusting, by a sensor ratio optimizer, a ratio of the current sensor to maintain charging, wherein the current sensor includes three-phase current sensors, and a voltage value as an input value is converted to a current value by using a ratio of the current sensor, when the current imbalance control is normally operated, determining whether the current sensor is deteriorated includes: sensing a temperature of an insulated gate bipolar transistor of each phase; comparing a difference value of the temperature sensing values of the insulated gate bipolar transistor of each phase with a predetermined reference value to identify a deteriorated current sensor and a deterioration situation.

2. The charge control method according to claim 1, wherein, the current sensor includes a U-phase current sensor, a V-phase current sensor, and a W-phase current sensor, and the current imbalance control is performed based on three-phase currents varied according to the adjusted ratio of the current sensor.

3. The charge control method according to claim 1, wherein, the ratio of the current sensor is adjusted up or down based on the identified deterioration situation.

4. The charge control method according to claim 1, wherein each phase includes two insulated gate bipolar transistors, and the reference value is applied differently for the two insulated gate bipolar transistors.

5. The charge control method according to claim 4, wherein, the reference values of the two insulated gate bipolar transistors have different signs according to the deterioration situation.

6. The charge control method according to claim 1, wherein the reference value is determined considering at least one of a load condition, a temperature sensor position deviation, a temperature sensing error, or a current sensor sensing error.

7. The charge control method according to claim 1, wherein the ratio adjustment of the current sensor is performed for a phase corresponding to the deteriorated current sensor. 8.The charging control method of claim 1, further comprising: when a result of the determination is that the current sensor is not detected to be deteriorated, determining that the current sensor is normally operated and maintaining charging. 9.A charging control apparatus of an electric vehicle that boosts a charging voltage using a motor and an inverter, the charging control apparatus comprising: a sensing apparatus configured to sense an internal temperature of the inverter and a current input to a three-phase input of the inverter from the motor; a deterioration determiner configured to determine whether a current imbalance control is normally operated based on a result of the current sensing during charging, and when the current imbalance control is normally operated, determine whether a current sensor is deteriorated based on a result of the temperature sensing; and a sensor ratio optimizer configured to adjust a ratio of the current sensor when a result of the determination is that the current sensor is detected to be deteriorated, wherein the current sensor includes three-phase current sensors, and a voltage value as an input value is converted to a current value by using a ratio of the current sensor, the deterioration determiner is configured to: sense a temperature of an insulated gate bipolar transistor of each phase; compare a difference value of the temperature sensing values of the insulated gate bipolar transistor of each phase with a predetermined reference value to identify a deteriorated current sensor and a deterioration situation.

10. The charging control device of an electric vehicle according to claim 9, wherein The current sensor includes a U-phase current sensor, a V-phase current sensor, and a W-phase current sensor, and the charging control device further includes a three-phase current imbalance controller configured to perform current imbalance control based on three-phase currents varied in proportion to the adjusted current sensor.

11. The charging control device of an electric vehicle according to claim 9, wherein The sensor proportion optimizer adjusts the proportion of the current sensor up or down based on the identified deterioration.

12. The charging control device of an electric vehicle according to claim 9, wherein Each phase includes two insulated gate bipolar transistors, and the reference value is applied differently for the two insulated gate bipolar transistors.

13. The charging control device of an electric vehicle according to claim 12, wherein The reference values of the two insulated gate bipolar transistors have different signs according to the deterioration.

14. The charging control device of an electric vehicle according to claim 9, wherein The reference value is determined considering at least one of a load condition, a temperature sensor position deviation, a temperature sensing error, or a current sensor sensing error.

15. The charging control device of an electric vehicle according to claim 9, wherein The sensor proportion optimizer adjusts the proportion of the current sensor for a phase corresponding to the current sensor in which the deterioration occurs.

16. The charging control device of an electric vehicle according to claim 9, wherein When the determined result is that no current sensor deterioration is detected, it is determined that the current sensor is operating normally, thereby maintaining charging.

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