Electric vehicle and its control method

Abstract

This invention provides an electric vehicle and a control method thereof that enable efficient charging and discharging of batteries based on a V2H device using DC power. [Solution] An electric vehicle and a method for controlling the same are introduced, comprising: a battery; DC charging / discharging terminals and AC charging / discharging terminals electrically connectable to an external device; a motor drive system including a drive motor and an inverter; a bidirectional power exchange device selectively connected to the DC charging / discharging terminals and AC charging / discharging terminals and performing bidirectional voltage control for power exchange between the connected charging / discharging terminals and the battery; and a controller that, when a DC-based external device is connected to the DC charging / discharging terminal, controls the motor drive system to perform power exchange between the connected external device and the battery based on the result of communication with the connected external device, or controls the bidirectional power exchange device to perform power exchange between the connected external device and the battery.

Description

Technical Field

[0001] The present invention relates to an electric vehicle capable of efficiently charging and discharging a battery based on a V2H (Vehicle to Home) device using direct current power, and a control method thereof.

Background Art

[0002] In recent years, as interest in the environment has increased, environmentally friendly vehicles equipped with an electric motor as a power source have been increasing. Environmentally friendly vehicles are also called electric vehicles, and a typical example is an electric vehicle (EV: Electric Vehicle).

[0003] At this time, the electric vehicle can be provided with a bidirectional power conversion device (or OBC, On Board Charger) that charges the battery from the grid power. Generally, the bidirectional power conversion device (OBC) can be composed of a power factor correction circuit (PFC, Power Factor Correction Circuit) that converts an external AC voltage into a DC voltage, and a DC-DC converter that adjusts the converted DC voltage to the voltage required by the battery.

[0004] Based on such power exchange technology of electric vehicles, a V2H (Vehicle-to-Home) system that enables power exchange between an electric vehicle and a home has attracted attention. At this time, by connecting a V2H device that converts and exchanges power between the electric vehicle and the home, bidirectional power exchange of the V2H system can be performed.

[0005] The matters described as the above background art are only for enhancing the understanding of the background of the present invention, and it should not be accepted as admitting that they correspond to the prior art already known to those having ordinary knowledge in the technical field.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention provides an electric vehicle and a control method thereof that enable DC power conversion between an external device and the electric vehicle, based on the configuration of a bidirectional power converter, when a V2H device using DC power is connected.

[0007] Furthermore, this invention provides an electric vehicle and its control method that have increased power conversion efficiency when a V2H device using DC power is connected.

[0008] The problems addressed by the present invention are not limited to those described above, and other problems not mentioned above will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0009] An electric vehicle according to one embodiment of the present invention for achieving the above objective may include: a battery; DC charging / discharging terminals and AC charging / discharging terminals that can be electrically connected to an external device; a motor drive system including a drive motor and an inverter; a bidirectional power exchange device selectively connected to the DC charging / discharging terminals and the AC charging / discharging terminals and performing bidirectional voltage control for power exchange between the connected charging / discharging terminals and the battery; and a controller that, when a DC-based external device is connected to the DC charging / discharging terminals, controls power exchange between the connected external device and the battery via the motor drive system based on the result of communication with the connected external device, or controls power exchange between the connected external device and the battery via the bidirectional power exchange device.

[0010] According to one embodiment, the bidirectional power exchange device may include a power factor correction circuit including a plurality of switches and a DC-DC converter including a plurality of switches.

[0011] According to one embodiment, when power is applied to the battery from the external device, the controller controls the power factor correction circuit in a boost converter topology that increases the voltage of the power applied from the external device, and when power is applied to the external device from the battery, the controller controls the power factor correction circuit in a buck converter topology that decreases the voltage of the power applied from the battery, thereby enabling power exchange between the external device and the battery via the bidirectional power exchange device.

[0012] According to one embodiment, the DC-DC converter can be configured as a bidirectional LLC resonant converter.

[0013] According to one embodiment, the controller can control the power factor correction circuit to convert the applied AC power to DC power when an external device is connected to the AC charging / discharging terminal and AC power is applied to the battery from the external device, and can control the power factor correction circuit to convert the DC power applied from the battery to AC power when an external device is connected to the AC charging / discharging terminal and power is applied to the external device from the battery.

[0014] According to one embodiment, when an external device is connected to the AC charging / discharging terminal, the controller can control the power factor correction circuit based on a totem pole topology or a push-pull topology.

[0015] According to one embodiment, the controller can keep the bidirectional power exchange device in the off state when it is controlled to perform power exchange between the connected external device and the battery via the motor drive system.

[0016] According to one embodiment, the controller can keep the inverter of the motor drive system in the off state when it is controlled to exchange power between the connected external device and the battery via the bidirectional power exchange device.

[0017] According to one embodiment, the communication result may include voltage information, current information, or power information output from the external device.

[0018] According to one embodiment, the DC charging / discharging terminal may include a busbar connecting the DC charging / discharging terminal to the bidirectional power exchange device.

[0019] A control method for an electric vehicle according to one embodiment of the present invention may include the steps of: determining whether a DC-based external device is connected to the DC charging / discharging terminal among the DC charging / discharging terminals and AC charging / discharging terminals to which the external device can be electrically connected; if the external device is connected to the DC charging / discharging terminal, the controller communicating with the connected external device; and, based on the result of communication with the connected external device, the controller controlling the motor drive system to perform power exchange between the connected external device and the battery, or controlling the bidirectional power exchange device to perform power exchange between the connected external device and the battery.

[0020] According to one embodiment, the bidirectional power exchange device may include a power factor correction circuit including a plurality of switches and a DC-DC converter including a plurality of switches.

[0021] According to one embodiment, the step of the controller performing power exchange between the external device and the battery via the bidirectional power exchange device is as follows: when power is applied from the external device to the battery, the controller controls the power factor correction circuit in a boost converter topology that increases the voltage of the power applied from the external device; and when power is applied from the battery to the external device, the controller controls the power factor correction circuit in a buck converter topology that decreases the voltage of the power applied from the battery.

[0022] According to one embodiment, the DC-DC converter can be constituted by a bidirectional LLC resonant converter.

[0023] According to one embodiment, it further includes a step of determining whether the external device is connected to the AC charging and discharging terminal, and a step of the controller controlling, based on the communication result with the external device, the AC power exchange between the external device and the battery through the bidirectional power exchange device. The step of controlling the AC power exchange between the external device and the battery is as follows: when the external device receives the application of AC power from the AC charging and discharging terminal to the battery, the controller controls the power factor improvement circuit to convert the received AC power into DC power; when power is applied from the battery to the external device, the controller can control the power factor improvement circuit to convert the DC power applied from the battery into AC power.

[0024] According to one embodiment, the step of controlling the AC power exchange between the external device and the battery can include the step of the controller controlling based on the totem pole topology or the push-pull topology of the power factor improvement device.

[0025] According to one embodiment, the step of controlling the power exchange between the connected external device and the battery through the motor drive system can further include the step of the controller maintaining the bidirectional power exchange device in an off state.

[0026] According to one embodiment, the step of controlling the power exchange between the connected external device and the battery through the bidirectional power exchange device can further include the step of maintaining the inverter of the motor drive system in an off state.

[0027] According to one embodiment, the communication result can include voltage information, current information, or power information output from the external device.

[0028] According to one embodiment, the DC charge / discharge terminal can include a bus bar connecting the DC charge / discharge terminal and the bidirectional power conversion device.

Effects of the Invention

[0029] For the electrified vehicle and its control method according to various embodiments of the present invention described above, when a V2H device using DC power is connected, power conversion is possible based on the configuration of the bidirectional power conversion device.

[0030] In addition, when a V2H device using DC power is connected, an electrified vehicle having increased power conversion efficiency and its control method can be provided.

[0031] The effects obtained by the present invention are not limited to the above-described effects, and other effects not described above will be clearly understood by those having ordinary knowledge in the technical field to which the present invention pertains from the following description.

Brief Description of the Drawings

[0032] [Figure 1] An electrified vehicle according to an embodiment of the present invention is shown. [Figure 2] It is a diagram for explaining a process in which a signal is transmitted when a V2H device using DC power according to an embodiment of the present invention is connected to a DC terminal. [Figure 3] It is a diagram (1 / 2) for explaining a bidirectional power conversion device according to an embodiment of the present invention. ​​​​​​​​ [Figure 7] The PWM signal, output voltage, and output power graph output to the third and sixth switches during second-mode DC power conversion according to one embodiment of the present invention are shown (3 / 3). [Figure 8] This is a flowchart illustrating the control process of an electric vehicle according to one embodiment of the present invention. [Modes for carrying out the invention]

[0033] With respect to embodiments of the present invention disclosed herein or in the application, any specific structural or functional description is merely illustrative to illustrate embodiments of the present invention, and embodiments of the present invention can be carried out in various forms and should not be construed as being limited to embodiments described herein or in the application.

[0034] Embodiments of the present invention can be modified in various ways and may take on various forms. Therefore, specific embodiments are illustrated in the drawings and described in detail in this specification or application. However, this should not be understood as limiting embodiments of the concept of the present invention to any particular disclosure, but rather as including all modifications, equivalents, or substitutions that fall within the spirit and technical scope of the present invention.

[0035] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as those generally understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted in the sense that they have in the context of the relevant art, and not in an ideal or overly formal sense unless expressly defined herein.

[0036] The embodiments disclosed herein will be described in detail below with reference to the attached drawings, however, Regardless of the designation, identical or similar components are assigned the same reference numeral, and redundant explanations regarding them are omitted.

[0037] In the following descriptions of embodiments, the term “already set” means that the numerical value of the parameter is predetermined when the parameter is used in a process or algorithm. The numerical value of the parameter may be set when the process or algorithm starts according to the embodiment, or during the interval in which the process or algorithm is performed.

[0038] The suffixes "module" and "part" used with respect to the constituent elements in the following description are added or mixed solely for the sake of ease of specification preparation and do not have any distinct meaning or role in themselves.

[0039] In describing the embodiments disclosed herein, if it is determined that a specific description of relevant known technology would obscure the gist of the embodiments disclosed herein, such detailed description will be omitted. Furthermore, the accompanying drawings are merely for the purpose of facilitating the understanding of the embodiments disclosed herein, and should be understood not as limiting the technical ideas disclosed herein, but as including all modifications, equivalents, or substitutions that fall within the concept and technical scope of the present invention.

[0040] Terms containing ordinal numbers, such as "first," "second," etc., can be used to describe various components, but these components are not limited by these terms. The aforementioned terms are used solely for the purpose of distinguishing one component from others.

[0041] When it is stated that one component is “connected” or “linked” to another component, it should be understood that it may be directly connected or linked to that other component, or that another component may be interposed between them. On the other hand, when it is stated that one component is “directly connected” or “directly linked” to another component, it should be understood that there is no other component interposed between them.

[0042] A singular expression includes plural expressions unless the context clearly indicates a different meaning.

[0043] In this specification, terms such as “includes” or “have” are intended to specify the presence of features, figures, stages, operations, components, parts, or combinations thereof as described in the specification, and should be understood not to preemptively exclude the possibility of the presence or addition of one or more other features, figures, stages, operations, components, parts, or combinations thereof.

[0044] Furthermore, the terms "Unit" or "Control Unit" included in names such as Motor Control Unit (MCU) and Hybrid Control Unit (HCU) are merely widely used terms for naming control devices that control vehicle-specific functions, and do not mean a generic function unit.

[0045] Figure 1 shows an electric vehicle according to an embodiment of the present invention.

[0046] Referring to Figure 1, the electric vehicle may include a DC charge / discharge terminal 110, an AC charge / discharge terminal 120, a motor drive system 200, a bidirectional power exchange device 300, and a battery 400.

[0047] The DC charging / discharging terminal 110 can connect an external device that uses DC power to the electric vehicle.

[0048] In this configuration, the first busbar 111 can be connected between the DC charge / discharge terminal 110 and the motor drive system 200. Here, external devices using DC power and the battery 400 can exchange power via the DC charge / discharge terminal 110, the first busbar 111, and the motor drive system 200.

[0049] Furthermore, the second busbar 112 can be connected between the DC charge / discharge terminal 110 and the bidirectional power exchange device 300. Here, an external device using DC power and the battery 400 can exchange power via the DC charge / discharge terminal 110, the second busbar 112, and the bidirectional power exchange device 300.

[0050] In this case, the DC power charging and discharging process in which an external device using DC power and the battery 400 exchange power via the motor drive system 200 through the first busbar 111 is defined as "first-mode DC power conversion," and the DC power charging and discharging process in which an external device using DC power and the battery 400 exchange power via the bidirectional power exchange device 300 through the second busbar 112 is defined as "second-mode DC power conversion."

[0051] The AC charging / discharging terminal 120 can connect an external device that uses AC power to an electric vehicle. In this case, the process in which the external device that uses AC power is connected to the AC charging / discharging terminal 120 and the external device and the battery 400 exchange power via the bidirectional power exchange device 300 is defined as "AC power conversion". For example, AC power conversion may include a charging process in which AC power is converted to DC power via the bidirectional power exchange device 300 and charged in the battery 400, and a discharge process in which the DC power of the battery 400 is converted to AC power and transmitted to an external device that uses AC power.

[0052] The motor drive system 200 may include an inverter (not shown) with multiple switches, and a drive motor (not shown). The motor drive system 200 is also connected to a battery 400 and can exchange power with an external device that uses DC power. For example, during first-mode DC power conversion, if the voltage of the DC power transmitted from an external device via the DC charge / discharge terminal 110 and the first busbar 111 (e.g., 400V) is lower than the charging voltage of the battery 400 (e.g., 800V), the motor drive system 200 can be controlled so that the drive motor and inverter are configured in a boost converter topology, thereby boosting the voltage of the transmitted DC power to match the charging voltage of the battery 400.

[0053] The bidirectional power exchange device 300, also called a bidirectional on-board charger (OBC), may include a power factor correction circuit (310) and a DC-DC converter (320). In this case, the bidirectional power exchange device 300 can be selectively connected to either a DC charge / discharge terminal (110) or an AC charge / discharge terminal (120), and can perform bidirectional voltage control for power exchange between the connected charge / discharge terminal and the battery (400).

[0054] The power factor correction circuit 310 may include multiple switches.

[0055] Here, when an external device using AC power is connected to the AC charge / discharge terminal 120, the multiple switches included in the power factor correction circuit 310 can convert AC power to DC power or DC power to AC power. For example, when connected to the AC charge / discharge terminal 120 as an external device using AC power, the circuit can be controlled to convert AC power applied from the external device to DC power, or to convert DC power applied from the battery 400 to AC power. In this case, the power factor correction circuit 310 can be controlled based on a totem pole topology or a push-pull topology.

[0056] Furthermore, when an external device using DC power is connected to the DC charge / discharge terminal 110 and second-mode DC power conversion is performed, the multiple switches included in the power factor correction circuit 310 can be controlled based on a step-down converter topology or a boost converter topology. The specific configuration of the power factor correction circuit 310 and its operation when second-mode DC power conversion is performed will be described later in Figures 3 and 4.

[0057] The DC-DC converter 320 is connected to the power factor correction circuit 310 and the battery 400, and can adjust the voltage of the power applied to the battery 400 or the voltage of the power applied to an external device. In this case, the DC-DC converter 320 can be implemented as a bidirectional LLC resonant converter including multiple switches, multiple capacitors, and multiple inductors.

[0058] Battery 400 can store the power necessary for driving electric vehicles and for power exchange with external devices.

[0059] When a DC-based external device is connected to the DC charge / discharge terminal 110, the controller 500 can control the motor drive system 200 to perform power exchange between the connected external device and the battery 400 based on the results of communication with the connected external device, or it can control the motor drive system 200 to perform power exchange between the connected external device and the battery 400 via the bidirectional power exchange device 300.

[0060] The operation of the controller 500 when an external V2H device using DC power is connected will be explained in more detail below with reference to Figure 2.

[0061] Figure 2 is a diagram illustrating the process by which a signal is transmitted when a V2H device using DC power according to one embodiment of the present invention is connected to a DC terminal.

[0062] Referring to Figure 2, the electric vehicle 1 and the V2H device 2 are connected, illustrating the situation in which power is exchanged between the home 3 and the electric vehicle 1. Here, the controller 500 may include a Vehicle Charging Management System (VCMS) 510 that manages the voltage imbalance between the charger and the battery and adjusts the charging voltage, a Vehicle Control Unit (VCU) 520 that is responsible for the overall control of the vehicle and monitors the charging status, a Battery Management System (BMS) 530 that manages the battery temperature, voltage, and current during charging, a Motor Control Unit (MCU) 540 that controls the motor drive system 200, and an On-Board Charger Controller (OBC) 550 that controls the bidirectional power converter 300.

[0063] The V2H device 2 can perform power exchange between the home 3 and the electric vehicle 1. In this case, the V2H device 2 can be considered a device that performs DC power exchange between the V2H device 2 and the electric vehicle 1, and power exchange between the V2H device 2 and the home, based on the CHADEMO standard, which is the charging standard in Japan.

[0064] When the V2H device 2 is connected to the DC charge / discharge terminal 110 of the electric vehicle 1, the VCMS510 can communicate with the V2H device 2 and exchange information. In this case, the communication method between the VCMS510 and the V2H device 2 can be the CAN (Controller Area Network) communication technique. Here, the VCMS510 can transmit voltage information, current information, or power information from the V2H device 2, which has been transmitted via communication with the V2H device 2, to the VCU520.

[0065] Based on the communication results with the V2H device 2, the VCU 520 can determine whether a first-mode DC power exchange is applicable, in which the V2H device 2 and the battery 400 exchange power via the control of the motor drive system 200 of the MCU 540, or whether a second-mode DC power exchange is applicable, in which the V2H device 2 and the battery 400 exchange power via the control of the bidirectional power exchange device 300 of the OBC controller 550. For example, the VCU 520 can determine how to control the motor drive system 200 by first-mode DC power exchange or how to control the bidirectional power exchange device 300 by second-mode DC power exchange based on whether or not it has received information from the V2H device 2 indicating that it is the V2H device 2.

[0066] The BMS530 can acquire information from the motor drive system 200, the bidirectional power exchange device 300, and the battery 400, and transmit the acquired information to the VCU520. For example, when second-mode charge / discharge control is being performed, the BMS530 can acquire information such as voltage, current, and temperature of multiple switching elements included in the motor drive system 200 and transmit it to the VCU520.

[0067] Furthermore, when the OBC controller 550 receives a second-mode DC power exchange control command from the VCU 520, it can perform either charge control, which controls the bidirectional power exchange device 300 so that power is applied from the V2H device 2 to the battery 400, or discharge control, which controls the bidirectional power exchange device 300 so that power is applied from the battery 400 to the external V2H device 2.

[0068] The operation of the bidirectional power exchange device 300 during second-mode DC power exchange will be explained below with reference to Figures 3 and 4.

[0069] Figures 3 and 4 illustrate a bidirectional power exchange according to one embodiment of the present invention.

[0070] Referring to Figures 3 and 4, the bidirectional power exchange 300 may include a power factor correction circuit 310 including first to sixth switches Q1, Q2, Q3, Q4, Q5, and Q6; a bidirectional DC-DC converter 320 including seventh to tenth switches Q7, Q8, Q9, and Q10, and eleventh to fourteenth switches Q11, Q12, Q13, and Q14; an EMI filter 330 including first to third windings L1, L2, and L3, first relay RlyA, and second relay RlyB; and a link capacitor Clink.

[0071] The second-mode DC power exchange may include second-mode charging, in which power is applied to the battery 400 from the V2H device 2 connected to the electric vehicle 1, and second-mode discharging, in which power is applied to the V2H device 2 from the battery 400.

[0072] In the second mode of charging, the power from the V2H device 2 can be applied to the battery 400 via the EMI filter 330, the power factor correction circuit 310, and the DC-DC converter 320.

[0073] Here, the power factor correction circuit 310 can boost the DC voltage of the power output from the V2H device 2 and apply it to the link capacitor Clink. More specifically, the third switch Q3 of the power factor correction circuit 310 is kept in the off state, the sixth switch Q6 is kept in the on state, and the first relay RlyA and the second relay RlyB of the EMI filter 330 are both kept in the off state, thereby ensuring that the phase of the Clink voltage is not changed. In addition, the first switch Q1, second switch Q2, fourth switch Q4, and fifth switch Q5 of the power factor correction circuit 310 are controlled by a boost converter topology, which can boost the magnitude of the DC voltage output to the link capacitor Clink. At this time, the OBC controller 550 can adjust the magnitude of the DC voltage output to the link capacitor Clink by adjusting the duty cycle of the PWM signals transmitted to the first switch Q1, second switch Q2, fourth switch Q4, and fifth switch Q5.

[0074] Furthermore, the bidirectional DC-DC converter 320 can boost the voltage of the link capacitor Clink output from the power factor correction circuit 310 and apply power to the battery 400. At this time, the 7th to 10th switches Q7, Q8, Q9, and Q10, and the 11th to 14th switches Q11, Q12, Q13, and Q14 of the bidirectional DC-DC converter 320 are controlled based on the bidirectional LLC resonant circuit topology, thereby enabling the boosted power to be applied to the battery 400.

[0075] On the other hand, in the second mode discharge, the power of the battery 400 can be applied to the V2H device 2 via the DC-DC converter 320, the power factor correction circuit 310, and the EMI filter 330.

[0076] Here, the bidirectional DC-DC converter 320 can apply voltage-dropped power to the link capacitor Clink. At this time, the 7th to 10th switches Q7, Q8, Q9, and Q10 and the 11th to 14th switches Q11, Q12, Q13, and Q14 of the bidirectional DC-DC converter 320 are controlled based on the bidirectional LLC resonant circuit topology, thereby enabling the dropped Clink voltage to be applied to the link coffee sitter Clink.

[0077] Furthermore, in the second mode discharge, the power factor correction circuit 310 can reduce the Clink voltage output from the DC-DC converter back to the DC voltage output to the V2H device 2. More specifically, the third switch Q3 of the power factor correction circuit 310 is kept in the off state, the sixth switch Q6 is kept in the on state, and the first relay RlyA and the second relay RlyB of the EMI filter 330 are both kept in the off state, thereby preventing the phase of the Clink voltage from changing. In addition, the first switch Q1, second switch Q2, fourth switch Q4, and fifth switch Q5 of the power factor correction circuit 310 are controlled in a step-down converter topology, thereby reducing the magnitude of the DC voltage output to the EMI filter 330. At this time, the OBC controller 550 can control the magnitude of the DC voltage output to the EMI filter 330 to correspond to the voltage of the V2H device 2 by adjusting the duty cycle of the PWM signals transmitted to the first switch Q1, second switch Q2, fourth switch Q4, and fifth switch Q5.

[0078] Figures 5 to 7 show the PWM signals, output voltage, and output power graphs, respectively, output to the third and sixth switches during second-mode DC power conversion according to one embodiment of the present invention.

[0079] Referring to Figure 5, the voltage graphs of the PWM3 signal output to the third switch Q3 and the PWM6 signal output to the sixth switch Q6 during second-mode DC power exchange, which exchanges power based on the bidirectional power exchange device 300, are shown.

[0080] At the start of the second-mode DC power exchange, the PWM3 signal output to the third switch Q3 can remain in the off state, while the PWM6 signal output to the sixth switch Q6 can remain in the on state.

[0081] Referring to Figure 6, the input voltage input from the external V2H device 2 to the bidirectional power exchange device 300 can be 400V from the time the second-mode DC power exchange starts, and referring to Figure 7, the input power input from the external V2H device 2 to the bidirectional power exchange device 300 can be 5kW from the time the second-mode DC power exchange starts.

[0082] In this case, when power is exchanged with an external device that uses low power, such as the V2H device 2, based on the bidirectional power exchange device 300, compared to when power exchange is performed in the motor drive system 200, switching operations can be performed in the low-power section, enabling switching operations close to ZVS (Zero Voltage Switching) and ZCS (Zero Current Switching), and switching losses can be greatly reduced in the process.

[0083] More specifically, when exchanging power between a V2H device 2 and a battery 400 that uses 5kW to 10kW of power via a motor drive system 200 designed for power in the 300kW range, the power conversion efficiency is only about 50%.

[0084] On the other hand, when power is exchanged between the V2H device 2 and the battery 400 via the bidirectional power exchange device 300, the power conversion efficiency is approximately 90% or more, which is an improvement of approximately 40% or more compared to when power conversion is performed via the existing motor drive system 200.

[0085] The following describes a more specific control process when a V2H device 2 using 5kW to 10kW of power is connected to an electric vehicle 1, with reference to Figures 8 and 9.

[0086] Figure 8 is a flowchart illustrating the control process of an electric vehicle according to one embodiment of the present invention.

[0087] Referring to Figure 8, when an external device is connected to an electric vehicle, the controller 500 can determine the electric vehicle model (S810). At this time, the controller 500 can determine whether the electric vehicle is an 800V model, a 400V model, or any other model based on pre-stored settings corresponding to the electric vehicle model.

[0088] If it is determined that the electric vehicle does not fall under the category of a model using an 800V battery (No. S811), the controller 500 can determine whether the electric vehicle falls under the category of a model using a 400V battery (S812), or whether it falls under the category of an FCEV model (S813). However, the above-described method for determining the model of the electric vehicle is illustrative, and the controller 500 may be designed to determine the model of the electric vehicle based on other information such as the voltage of the battery 400, or to have a different order of determination for each model.

[0089] On the other hand, if it is determined that the electric vehicle is a model using an 800V battery (Yes in S811), the controller 500 can determine the model of the external device connected to the electric vehicle (S820).

[0090] Specifically, the charger model can be determined to be a domestic model (e.g., CCS1 or 220V) (S821), a North American model (e.g., CCS1 or 120V) (S822), a European model (e.g., CCS2 or 230V) (S823), a Japanese model (e.g., CHAdeMO) (S824), or another model (e.g., China (GBT)) (S825). Here, the controller 500 can determine the charger model based on whether the charge / discharge terminal to which the external device is connected corresponds to the charge / discharge terminal for each model.

[0091] If the external device is determined to be a Japanese model (e.g., CHAdeMO) (Yes in S824), the controller 500 communicates with the external device to exchange information (S830) and determines whether the external device is a V2H device 2 based on the results of the communication with the external device (S840). At this time, the V2H device 2 transmits information to the controller 500 via CAN communication indicating that it is a V2H device 2, and the controller 500 can determine whether the connected external device is a V2H device 2 based on the results of the CAN communication. Here, the results of the communication with the external device may include information such as whether the device is a V2H device 2 and the voltage and current output from the external device.

[0092] If the external device is determined to be V2H device 2 (Yes in S840), the controller 500 can turn on the bidirectional power exchange device 300 and keep the inverter of the motor drive system 200 in the off state (S851). At this time, the controller 500 can control the first relay RlyA and the second relay RlyB included in the EMI filter 330 to remain in the off state (S852).

[0093] Furthermore, the controller 500 can determine whether it is in charging mode or discharging mode (S853). Here, whether it is in charging mode or discharging mode can be determined based on whether current is applied from the V2H device 2 to the battery 400 or from the battery 400 to the V2H device 2.

[0094] If it is determined that the device is in charging mode (Yes in S853), the VCU (not shown) of the controller 500 sends a charging current command for the battery 400 to the OBC controller (not shown) of the bidirectional power exchange device 300 (S854A), and the OBC controller (not shown) can start controlling the power exchange device 300 to charge the battery 400 based on the transmitted charging current command (S855A). At this time, the OBC controller (not shown) can control a plurality of switches included in the power factor correction circuit 310 in a boost converter topology that increases the voltage of the power applied from an external device.

[0095] On the other hand, if discharge mode is determined (No. in S853), the VCU (not shown) of the controller 500 transmits a DC output voltage command to the OBC controller (not shown) of the bidirectional power exchange device 300 (S854B), and the OBC controller (not shown) can start discharge control to apply power from the battery 400 to the external device based on the transmitted DC output voltage command. At this time, the OBC controller (not shown) can control the multiple switches included in the power factor correction circuit 310 in a step-down converter topology that reduces the voltage of the power applied from the battery 400.

[0096] Furthermore, if it is determined that the external device is not V2H device 2 (No. in S840), the controller 500 can keep the bidirectional power exchange device 300 in the off state and turn on the inverter of the motor drive system 200 (S861). At this point, the VCU (not shown) of the controller 500 transmits a neutral terminal voltage command (S862) and a charging current command for the battery 400 to the MCU (not shown) that controls the inverter of the motor drive system 200 (S863), and the MCU (not shown) can start controlling the motor drive system 200 to charge the battery 400 based on the transmitted neutral terminal voltage command and charging current command for the battery 400 (S864).

[0097] Based on the electric vehicle and its control method according to one embodiment of the present invention, power conversion between the V2H device and the electric vehicle can be performed using the configuration of a bidirectional power converter.

[0098] Furthermore, based on the electric vehicle and its control method according to one embodiment of the present invention, it is possible to significantly increase the power conversion efficiency compared to power conversion using a conventional motor drive system while minimizing the number of components added to the configuration of a conventional electric vehicle.

[0099] On the other hand, the present invention described above can be realized as computer-readable code on a medium on which a program is recorded. Computer-readable media include all kinds of recording devices that store data that can be read by a computer system. Examples of computer-readable media include HDDs (Hard Disk Drives), SSDs (Solid State Disks), SDDs (Silicon Disk Drives), ROMs, RAMs, CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and the like. Therefore, the above detailed description should not be interpreted restrictively in any way, but should be considered illustrative. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included within the scope of the present invention.

Claims

1. Battery and DC charging / discharging terminals and AC charging / discharging terminals that can be electrically connected to external devices, A motor drive system including a drive motor and inverter, A bidirectional power exchange device is selectively connected to the DC charging / discharging terminal and the AC charging / discharging terminal, and performs bidirectional voltage conversion control for power exchange between the connected charging / discharging terminal and the battery. An electric vehicle comprising: a controller that, when a DC-based external device is connected to the DC charging / discharging terminal, controls, based on the result of communication with the connected external device, to perform power exchange between the connected external device and the battery via the motor drive system, or controls, to perform power exchange between the connected external device and the battery via the bidirectional power exchange device.

2. The aforementioned bidirectional power exchange device is A power factor correction circuit having multiple switches, An electric vehicle according to claim 1, comprising a DC-DC converter having a plurality of switches.

3. The controller is, When power is applied to the battery from the external device, the power factor correction circuit is controlled in a boost converter topology that increases the voltage of the power applied from the external device. The electric vehicle according to claim 2, wherein when power is applied from the battery to the external device, the power factor correction circuit is controlled in a step-down converter topology that reduces the voltage of the power applied from the battery, thereby performing power exchange between the external device and the battery via the bidirectional power exchange device.

4. The electric vehicle according to claim 2, wherein the DC-DC converter is composed of a bidirectional LLC resonant converter.

5. The controller is, When an external device is connected to the AC charging / discharging terminal and AC power is applied to the battery from the external device, the power factor correction circuit is controlled to convert the applied AC power into DC power. The electric vehicle according to claim 2, wherein when an external device is connected to the AC charging / discharging terminal and power is applied from the battery to the external device, the power factor correction circuit is controlled to convert the DC power applied from the battery to AC power.

6. The controller is, The electric vehicle according to claim 5, wherein when an external device is connected to the AC charging / discharging terminal, the power factor correction circuit is controlled based on a totem pole topology or a push-pull topology.

7. The controller is, The electric vehicle according to claim 1, wherein the motor drive system is controlled to perform power exchange between the connected external device and the battery, and the bidirectional power exchange device is kept in the off state.

8. The controller is, The electric vehicle according to claim 1, wherein the inverter of the motor drive system is kept in the off state when the system is controlled to perform power exchange between the connected external device and the battery via the bidirectional power exchange device.

9. The controller is, The electric vehicle according to claim 1, wherein, as a result of communication with the connected external device, if the connected external device is determined to be a V2H device, the system controls the bidirectional power exchange device to perform power exchange between the connected external device and the battery.

10. The aforementioned DC charging / discharging terminal is The electric vehicle according to claim 1, further comprising a busbar connecting the DC charging / discharging terminal and the bidirectional power exchange device.

11. A step of determining whether a DC-based external device is connected to the DC charging / discharging terminal of the DC charging / discharging terminal and AC charging / discharging terminal that can be electrically connected to the external device, When the external device is connected to the DC charging / discharging terminal, the controller communicates with the connected external device. A method for controlling an electric vehicle, comprising the steps of: a controller controlling, based on the result of communication with the connected external device, to perform power exchange between the connected external device and the battery via the motor drive system, or to perform power exchange between the connected external device and the battery via the bidirectional power exchange device.

12. The aforementioned bidirectional power exchange device is A power factor correction circuit having multiple switches, A control method for an electric vehicle according to claim 11, comprising a DC-DC converter having a plurality of switches.

13. The step of performing power exchange between the external device and the battery via the bidirectional power exchange device is: A control method for an electric vehicle according to claim 12, wherein when power is applied to the battery from the external device, the controller controls the power factor correction circuit in a boost converter topology that increases the voltage of the power applied from the external device, and when power is applied to the external device from the battery, the controller controls the power factor correction circuit in a step-down converter topology that decreases the voltage of the power applied from the battery.

14. The DC-DC converter is A control method for an electric vehicle according to claim 12, comprising a bidirectional LLC resonant converter.

15. The steps include determining whether the external device is connected to the AC charging / discharging terminal, The controller further includes the step of controlling the exchange of AC power between the external device and the battery via the bidirectional power exchange device, based on the result of communication with the external device, The control step in which AC power exchange between the external device and the battery is performed is: A control method for an electric vehicle according to claim 12, wherein when the external device receives AC power from the AC charging / discharging terminal to the battery, the controller controls the power factor correction circuit to convert the received AC power to DC power, and when power is applied from the battery to the external device, the controller controls the power factor correction circuit to convert the DC power applied from the battery to AC power.

16. The step of controlling the exchange of AC power between the external device and the battery is: A method for controlling an electric vehicle according to claim 15, wherein the controller controls the power factor correction device based on a totem pole topology or a push-pull topology.

17. The step of controlling the motor drive system to perform power exchange between the connected external device and the battery is: The method for controlling an electric vehicle according to claim 11, further comprising the step of the controller keeping the bidirectional power exchange device in an off state.

18. The step of controlling the exchange of power between the connected external device and the battery via the bidirectional power exchange device is: The method for controlling an electric vehicle according to claim 11, further comprising the step of keeping the inverter of the motor drive system in an off state.

19. The controller is, A control method for an electric vehicle according to claim 11, wherein, as a result of communication with the connected external device, if the connected external device is determined to be a V2H device, the control is performed so that power is exchanged between the connected external device and the battery via the bidirectional power exchange device.

20. The control method for an electric vehicle according to claim 11, wherein the DC charging / discharging terminal includes a busbar connecting the DC charging / discharging terminal to the bidirectional power exchange device.

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