阅读说明：本技术 用于车辆的车载充电器控制装置和方法及包括该控制装置的系统 (On-board charger control device and method for vehicle and system including the same ) 是由 李祥圭 林珍圭 郑胜勉 于 2020-10-20 设计创作，主要内容包括：本发明涉及用于车辆的车载充电器控制装置和方法及包括该控制装置的系统。所述车载充电器控制装置包括：测量器,其测量三相OBC的各相的电压；以及控制器,其利用各相的电压来计算各相的阻抗。在三相OBC开始进行充电之前测量所述电压。控制器还计算各相的充电量,所述各相的充电量与各相的阻抗相对应,并基于计算出的各相的充电量来调整充电。(The invention relates to an on-board charger control device and method for a vehicle and a system including the control device. The on-vehicle charger control device includes: a measuring device that measures voltages of respective phases of the three-phase OBC; and a controller that calculates an impedance of each phase using the voltage of each phase. The voltage is measured before the three-phase OBC starts charging. The controller also calculates a charge amount of each phase corresponding to the impedance of each phase, and adjusts the charging based on the calculated charge amount of each phase.)

1. An on-board charger control device for a vehicle, comprising:

a measurer configured to measure voltages of respective phases of the three-phase vehicle-mounted charger; and

a controller configured to:

calculating impedance of each phase using voltage of each phase measured before a three-phase vehicle-mounted charger starts charging;

calculating a charge amount of each phase, the charge amount of each phase corresponding to an impedance of each phase;

the charging is adjusted based on the calculated amount of charge of each phase.

2. The on-board charger control device for a vehicle according to claim 1, wherein the controller is configured to: the current supplied to each phase is increased after the voltage of each phase is measured before the charging is started.

3. The on-board charger control device for a vehicle according to claim 2, wherein the controller is configured to: after the current is increased, the measurer is operated to measure the voltages of the phases of the three-phase vehicle-mounted charger.

4. The on-board charger control device for a vehicle according to claim 3, wherein the controller is configured to: calculating a voltage drop value, which is a difference between the voltage of each phase measured before starting charging and the voltage of each phase measured after increasing the current.

5. The on-board charger control device for a vehicle according to claim 4, wherein the controller is configured to: a phase difference between the voltage of each phase and the current of each phase is calculated.

6. The on-board charger control device for a vehicle according to claim 5, wherein the controller is configured to: calculating impedances of respective phases of the three-phase vehicle-mounted charger based on the voltage drop value and a phase difference between the voltage and the current.

7. The on-board charger control device for a vehicle according to claim 1, wherein the controller is configured to: an amount of charge is calculated, which is inversely proportional to the impedance.

8. The on-board charger control device for a vehicle according to claim 7, wherein the controller is configured to: the amount of charge of each phase is calculated using the voltage of each phase measured before the start of charging and the impedance of each phase.

9. The on-board charger control device for a vehicle according to claim 8, wherein the controller is configured to:

in response to determining that the voltage of a first phase among the three phases measured before the start of charging is less than a predetermined reference value, a value obtained by dividing the voltage of the first phase measured before the start of charging by the impedance of the first phase is subtracted from the amount of current uniformly distributed to the total amount of supplied charge to calculate the amount of charge supplied to the first phase.

10. The on-board charger control device for a vehicle according to claim 8, wherein the controller is configured to:

in response to determining that the voltage of the second phase among the three phases measured before the start of charging is greater than a predetermined reference value, the amount of current obtained by evenly dividing the total supplied amount of charge is added to a value obtained by dividing the voltage of the second phase measured before the start of charging by the impedance of the second phase to calculate the amount of charge supplied to the second phase.

11. The on-board charger control device for a vehicle according to claim 8, wherein the controller is configured to: an intermediate value among the three-phase voltage values measured before the start of charging is set as a reference value for calculating the amount of charge.

12. A vehicle system, comprising:

a three-phase vehicle-mounted charger; and

and an in-vehicle charger control device configured to calculate an impedance of each phase using a voltage of each phase measured before the three-phase in-vehicle charger starts charging, calculate a charge amount of each phase corresponding to the impedance of each phase, and adjust charging based on the calculated charge amount of each phase.

13. A control method for an on-board charger of a vehicle, comprising:

measuring, by a control device, voltages of respective phases of a three-phase vehicle-mounted charger;

calculating, by the control device, an impedance of each phase using the voltage of each phase;

the control device calculates a charge amount of each phase corresponding to the impedance of each phase and adjusts the charging based on the calculated charge amount of each phase.

14. The control method of claim 13, wherein measuring voltages of the phases of the three-phase onboard charger comprises:

before the three-phase vehicle-mounted charger starts charging, measuring the voltage of each phase by the control device;

before the three-phase vehicle-mounted charger starts charging, the control device adjusts the magnitude of the current supplied to each phase according to the voltage unbalance degree of each phase.

15. The control method of claim 14, wherein calculating the impedance of each phase comprises:

the current supplied to each phase is increased by the control means.

16. The control method of claim 15, wherein calculating the impedance of each phase further comprises:

after the current is increased, the voltage of each phase of the three-phase vehicle-mounted charger is measured by the control device.

17. The control method of claim 16, wherein calculating the impedance of each phase further comprises:

calculating, by the control device, a voltage drop value that is a difference between the voltage of each phase measured before the start of charging and the voltage of each phase measured after the current is increased.

18. The control method of claim 17, wherein calculating the impedance of each phase further comprises:

the phase difference between the voltage of each phase and the current of each phase is calculated by the control device.

19. The control method of claim 18, wherein calculating the impedance of each phase further comprises:

calculating, by the control device, impedances of respective phases of the three-phase vehicle-mounted charger based on the voltage drop value and the phase difference between the voltage and the current.

20. The control method of claim 19, wherein adjusting charging comprises:

an amount of charge is calculated by the control device, the amount of charge being inversely proportional to the impedance.

Technical Field

The present invention relates to an On Board Charger (OBC) control apparatus and method for a vehicle and a system including the same, and more particularly, to a technique of solving a power imbalance of a three-phase OBC.

Background

Due to environmental regulations in north america and europe, there is an increasing demand for environmentally friendly vehicles, such as plug-in hybrid vehicles (PHEVs)/Electric Vehicles (EVs), and thus the PHEVs and EVs are the focus of attention. One of the consumers' concerns about such environmentally friendly vehicles is the charging travel distance for long distance travel. The capacity of the high voltage battery needs to be increased to increase the travel distance. It is also necessary to consider increasing the capacity of an on-board charger (OBC) for charging the high-voltage battery together with increasing the capacity of the high-voltage battery to maintain any degree of charging time before the increase after increasing the capacity of the high-voltage battery.

However, increasing the capacity of an OBC by a factor of 2 to 4 results in increased size and cost. High power OBCs are currently being developed to charge batteries using three phases of electricity, since increasing the capacity of an OBC using single phase electricity can result in power imbalance. Specifically, for an OBC that utilizes three-phase power, the individual phase power should be equalized and controlled separately.

However, when control is performed to uniformly supply each phase of electricity in a state where the supplied electricity is unbalanced, the electricity imbalance may become more serious. Further, when the power unbalance becomes more serious, the three-phase transformer may be overloaded, and a wrong operation of the electric load using three-phase power may occur. In particular, when the three-phase OBC operates in a state where a single-phase load on one side is excessively used, since the three phases are expected to equally receive power, the phase imbalance may become more serious.

Disclosure of Invention

The invention provides an OBC control device and method for a vehicle and a system comprising the control device, wherein the OBC control device is used for: when three-phase power of the three-phase OBC is charged in an unbalanced state, the unbalance is solved by calculating three-phase unbalance and differently supplying power consumed by each phase, thereby improving safety of the used power.

The technical problems to be solved by the inventive concept are not limited to the above-described problems, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art to which the present invention pertains from the following description.

According to an aspect of the present invention, an OBC control apparatus for a vehicle may include: a measurer configured to measure voltages of respective phases of the three-phase OBC; and a controller configured to calculate an impedance of each phase using a voltage of each phase measured before the three-phase OBC starts charging, calculate a charge amount of each phase corresponding to the impedance of each phase, and adjust charging based on the calculated charge amount of each phase.

In an exemplary embodiment, the controller may be configured to increase the current supplied to each phase after measuring the voltage of each phase before starting charging. In addition, the controller may be configured to operate the measurer to measure voltages of the phases of the three-phase OBC after increasing the current, and may be configured to calculate a voltage drop value, which is a difference between the voltage of each phase measured before starting charging and the voltage of each phase measured after increasing the current.

The controller may be configured to calculate a phase difference between the voltage of each phase and the current of each phase. In addition, the controller may be configured to calculate impedances of the phases of the three-phase OBC based on the voltage droop and a phase difference between the voltage and the current. The controller may be configured to calculate an amount of charge that is inversely proportional to the impedance.

Further, the controller may be configured to calculate the amount of charge of each phase using the voltage of each phase measured before starting charging and the impedance of each phase. The controller may be configured to subtract a value obtained by dividing the voltage of the first phase measured before the start of charging by the impedance of the first phase from an amount of current uniformly distributed to a total supplied amount of charge when the voltage of the first phase measured before the start of charging is less than a predetermined reference value to calculate the amount of charge supplied to the first phase.

In an exemplary embodiment, the controller may be configured to add an amount of current obtained by uniformly distributing a total supplied charge amount to a value obtained by dividing a voltage of the second phase measured before starting the charging by an impedance of the second phase to calculate a charged amount supplied to the second phase, when the voltage of the second phase among the three phases measured before starting the charging is greater than a predetermined reference value. The controller may be configured to: the middle value among the voltage values of the three phases measured before the start of charging is set as a reference value for calculating the amount of charge.

According to another aspect of the present invention, a vehicle system may include a three-phase OBC and an OBC control device configured to calculate an impedance of each phase using a voltage of each phase before a three-phase on-board charger starts charging, calculate a charge amount of each phase corresponding to the impedance of each phase, and adjust charging based on the calculated charge amount of each phase. According to another aspect of the present invention, a method of operating an OBC for a vehicle may include: the voltage of each phase of the three-phase OBC is measured, the impedance of each phase is calculated using the voltage of each phase, the charge amount of each phase is calculated, the charge amount of each phase corresponds to the impedance of each phase, and the charging is adjusted based on the calculated charge amount of each phase.

In an exemplary embodiment, measuring the voltage may include: measuring the voltage of each phase before the three-phase OBC starts to charge; and adjusting the magnitude of the current supplied to each phase based on the voltage imbalance of each phase before the three-phase OBC starts charging. Additionally, calculating the impedance of each phase may include increasing the current supplied to each phase. Calculating the impedance of each phase may further comprise: after increasing the current, the voltage of each phase of the three-phase OBC is measured.

Further, calculating the impedance of each phase may include: calculating a voltage drop value, which is a difference between the voltage of each phase measured before starting charging and the voltage of each phase measured after increasing the current. Calculating the impedance of each phase may further include calculating a phase difference between the voltage of each phase and the current of each phase.

In an exemplary embodiment, calculating the impedance of each phase may further include: calculating impedances of respective phases of a three-phase OBC based on the voltage drop value and a phase difference between the voltage and the current. Adjusting the charging may include calculating an amount of charge that is inversely proportional to the impedance.

Drawings

The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which:

fig. 1 is a block diagram showing a configuration of an OBC system for a vehicle according to an exemplary embodiment of the present invention;

fig. 2 is a block diagram illustrating an example of connecting an electrical load of an OBC system for a vehicle according to an exemplary embodiment of the present invention;

fig. 3 is a block diagram showing a configuration of an OBC control apparatus for a vehicle according to an exemplary embodiment of the present invention;

FIG. 4 is a graph illustrating variations in voltage and current for a three-phase OBC for a vehicle according to an exemplary embodiment of the present invention;

fig. 5 is a graph illustrating phase differences between voltages and currents of a three-phase OBC for a vehicle according to an exemplary embodiment of the present invention; and

fig. 6 is a flowchart illustrating a control method of an OBC for a vehicle according to an exemplary embodiment of the present invention.

Detailed Description

It should be understood that the term "vehicle" or "vehicular" or other similar terms as used herein generally includes motor vehicles such as passenger automobiles including Sport Utility Vehicles (SUVs), buses, vans, various commercial vehicles, watercraft including various boats, ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from non-petroleum sources). As referred to herein, a hybrid vehicle is a vehicle having two or more power sources, such as both gasoline-powered and electric-powered vehicles.

While the exemplary embodiments are described as utilizing multiple units to perform the exemplary processes, it should be understood that the exemplary processes may also be performed by one or more modules. Further, it should be understood that the term controller/control unit refers to a hardware device that includes a memory and a processor, and is specifically programmed to perform the processes described herein. The memory is configured to store modules, and the processor is specifically configured to execute the modules to perform one or more processes described further below.

Furthermore, the control logic of the present invention may be embodied as a non-transitory computer readable medium on a computer readable medium containing executable program instructions executed by a processor, controller/control unit, or the like. Examples of computer readable media include, but are not limited to, ROM, RAM, Compact Disc (CD) -ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage. The computer readable recording medium CAN also be distributed over network coupled computer systems so that the computer readable medium is stored and executed in a distributed fashion, for example, by a telematics server or a Controller Area Network (CAN).

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. 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, values, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, values, 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.

Unless specifically stated or otherwise apparent from the context, the term "about" as used herein is understood to be within the normal tolerance of the art, e.g., within an average of 2 standard deviations. "about" can be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless the context clearly dictates otherwise, all numbers provided herein are modified by the term "about".

Some exemplary embodiments of the present invention will be described in detail below with reference to exemplary drawings. When a reference numeral is added to a component of each figure, it should be noted that the same reference numeral is assigned even when the same or equivalent component is shown on other figures. In addition, in describing embodiments of the present invention, detailed descriptions of well-known features or functions are excluded so as not to unnecessarily obscure the gist of the present invention.

In describing components according to embodiments of the present invention, terms such as first, second, "A", "B", "a", "B", and the like may be utilized. These terms are only used to distinguish one component from another component, and do not limit the nature, order, or sequence of the constituent components. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms defined in commonly used dictionaries should be interpreted as having a meaning that is equivalent to their contextual meaning in the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Exemplary embodiments of the present invention will be described in detail below with reference to fig. 1 to 6. Fig. 1 is a block diagram showing a configuration of a vehicle system including an on-board charger (OBC) control apparatus for a vehicle according to an exemplary embodiment of the present invention. Fig. 2 is a block diagram illustrating an example of connecting an electrical load of an OBC system for a vehicle according to an exemplary embodiment of the present invention.

Referring to fig. 1 and 2, an OBC system for a vehicle according to an exemplary embodiment of the present invention may include: an OBC control device 100 for a vehicle, a three-phase OBC 200 and a three-phase transformer 300. The three-phase OBC 200 may be implemented as a three-phase circuit for large capacity charging. Although not shown in fig. 1 and 2, the three-phase OBC 200 may include: transformers, switching devices, etc. for each phase. Specifically, the three-phase OBC 200 may be connected in parallel for each phase, or may be composed by connecting a three-phase Power Factor Corrector (PFC) in parallel with three direct current-direct current (DC-DC) converters. Here, the DC-DC converter may be connected in a single phase.

The three-phase transformer 300 may be configured to convert power of each phase supplied from the three-phase OBC 200 and transmit the converted power to the high-voltage battery. Fig. 1 discloses a configuration in which a three-phase OBC 200 has an electrical load A, B or C connected to each phase. Fig. 2 discloses a configuration with additional single-phase loads E, F or G and electrical loads D connected to each phase for a three-phase OBC 200.

As shown in fig. 2, the single-phase loads E and F may be connected to a first phase of the three phases, the single-phase load G may be connected to a second phase, and the additional single-phase load is not connected to a third phase. Specifically, a power imbalance of each phase may occur. Therefore, the OBC control device 100 for a vehicle according to an exemplary embodiment of the present invention may be configured to calculate the difference between the voltages of the three phases, and may be configured to differently apply the amount of power supplied to each phase to control uniform power supply, despite the difference in the number or size of the electrical loads connected to each phase.

The OBC control apparatus 100 for a vehicle according to an exemplary embodiment of the present invention may be implemented in a vehicle. Specifically, the OBC control device 100 may be integrally configured with a controller in the vehicle, or may be implemented as a separate device to be connected with the controller of the vehicle through a separate connection device. When the three-phase power is charged in an unbalanced state, the OBC control apparatus 100 for a vehicle may be configured to calculate an unbalance degree of each phase, and may be configured to differently apply power consumed by each phase, thereby preventing the power unbalance.

Fig. 3 is a block diagram showing a configuration of an OBC control apparatus for a vehicle according to an exemplary embodiment of the present invention. The OBC control device 100 may include: measurer 110, memory 120, and controller 130. The measurer 110 may be configured to measure voltages of the phases of the three-phase OBC 200, currents of the phases, and phase differences between the currents and the voltages, and may be configured to transmit the measured values to the controller 130. In particular, the measurer 110 may include separate or integrated sensors to measure voltage, current, and phase difference between current and voltage. The voltage of each phase, the current of each phase, and the position of the phase difference between the current and the voltage may be D1, D2, D3, D4, D5, or D6 of fig. 1 and 2.

The memory 120 may be configured to store sensing results of the measurer 110 and data, algorithms, etc. required for the operation of the controller 130. As an example, the memory 120 may be configured to store voltage measurements for the phases and values calculated by the controller 130. The memory 120 may include at least one type of storage medium, such as a flash memory type memory, a hard disk type memory, a micro memory, a card type memory (e.g., a Secure Digital (SD) card or an eXtreme digital card), a Random Access Memory (RAM), a static RAM (sram), a Read Only Memory (ROM), a programmable ROM (prom), an electrically erasable prom (eeprom), a magnetic RAM (mram), a magnetic disk, and an optical disk.

The controller 130 may be electrically connected to the measurer 110, the memory 120, and the like, and may electrically control the respective components. The controller 130 may be circuitry configured to execute software instructions and may be configured to perform various data processing and calculations described below. The controller 130 may be configured to process signals communicated between various components of the OBC controller 100 for a vehicle. The controller 130 may be, for example, an Electronic Control Unit (ECU), a microcontroller unit (MCU), or another sub-controller loaded into the vehicle. Specifically, the controller 130 may be configured to determine the impedance unbalance of each phase using a voltage drop value (which is a difference between three-phase voltages measured before the three-phase OBC 200 starts charging and three-phase voltages measured after increasing currents supplied to the three phases), may be configured to calculate a charged amount of each phase corresponding to the impedance unbalance of each phase, and may be configured to adjust charging based on the calculated charged amount of each phase.

After measuring the voltages of the respective phases before starting charging to calculate voltage drop values of the respective phases of the three-phase OBC 200, the controller 130 may be configured to equally increase the currents supplied to the three phases and measure the voltages of the respective phases to calculate the voltage drop values. For example, when the voltages Va1, Vb1, and Vc1 of the three phases are 210V, 220V, and 230V, respectively, the controller 130 may be configured to determine that an imbalance of 10V occurs because the voltage of the a-phase (e.g., the first phase) is 10V smaller than the voltage of the b-phase (e.g., the second phase) based on the voltage of the b-phase (210V) (the intermediate value), and because the voltage of the c-phase (e.g., the third phase) is 10V larger than the voltage of the second phase. The controller 130 may be configured to equally increase the current supplied to each phase, measure voltages Va2, Vb2, and Vc2 of the three phases, and calculate values obtained by subtracting Va2, Vb2, and Vc2 from Va1, Vb1, and Vc1 as voltage drop values.

Fig. 4 is a graph illustrating changes in voltage and current of a three-phase OBC for a vehicle according to an exemplary embodiment of the present invention. As shown in fig. 4, the degree of voltage drop of each phase according to the increase in current supplied to each phase can be identified. In other words, when the current I1 increases to the current I2 after a certain period of time, the voltage V1 drops to the voltage V2, and V2-V1 may be voltage drop values. At this time, the saturation current amount may be a reference current amount for measurement. The controller 130 of fig. 3 may be configured to calculate the three-phase impedance using the increased voltage drop value according to the three-phase current and the phase difference between the three-phase voltage and the three-phase current.

Fig. 5 is a graph illustrating phase differences between voltages and currents of a three-phase OBC for a vehicle according to an exemplary embodiment of the present invention. As shown in fig. 5, the controller 130 of fig. 3 may be configured to measure a time when each of the values of the voltage and the current is "0" to obtain a time difference, and calculate a phase difference between the voltage and the current. The controller 130 may utilize various general schemes for calculating the phase difference between the voltage and the current.

After the current increases, the voltage of each phase is Va2, Vb2 or Vc 2. Here, the voltage drop value according to the increase in current is a value obtained by subtracting the voltage values Va2, Vb2, and Vc2 after the supply current is adjusted from the voltage values Va1, Vb1, and Vc1 before the start of charging. The controller 130 may be configured to calculate impedances Za, Zb, or Zc of the respective phases using the voltage drop values and the phase differences (as shown in equation 1 below), and determine an impedance unbalance of the respective phases, which is a difference between impedance values of the three phases.

Equation 1

Za＝(Va1<0°-Va2<0°)/Ia<θ

Zb＝(Vb1<0°-Vb2<0°)/Ib<θ

Zc＝(Vc1<0°-Vc2<0°)/Ic<θ

The controller 130 may be configured to calculate the amount of charge of each phase using the voltage of each phase measured before starting charging and the impedance of each phase. Specifically, the charge amount Ca, Cb, or Cc of each phase may be calculated as in equation 2 below.

Equation 2

Ca＝(Iideal–Va/Za)

Cb＝(Iideal+Vb/Zb)

Cc＝(Iideal+Vc/Zc)

Specifically, Iideal refers to equalizing the amount of current supplied to each phase under ideal conditions. When the supplied power is 6.6Kw, 2.2Kw (220V × 10A) should be supplied for each phase, and the amount of current supplied for equalization is 10A. Each charge amount in the above equation 2 refers to an amount of current. Accordingly, the controller 130 may be configured to calculate an amount of charge inversely proportional to the magnitude of the three-phase impedance. As in the above equation 2, the OBC control device 100 for a vehicle may be configured to calculate, as the charge amount of the a-phase, a value obtained by subtracting a value obtained by dividing the voltage (210V) of the a-phase by the impedance Za of the a-phase from the amount of current distributed in equilibrium, which is the amount of current supplied to each phase in an ideal state, and may be configured to calculate the charge amount supplied to the b-phase or the c-phase.

In response to determining that the voltage of the first phase among the three phases measured before the start of charging is less than the predetermined reference value, the controller 130 may be configured to calculate the amount of charge supplied to the first phase by subtracting a value obtained by dividing the voltage of the first phase measured before the start of charging by the impedance of the first phase from the amount of current obtained by uniformly distributing the total amount of supplied charge. In response to determining that the voltage of the second phase among the three phases measured before the start of the charging is greater than the predetermined reference value, the controller 130 may be configured to calculate the amount of charge supplied to the second phase by adding a value obtained by dividing the voltage of the second phase measured before the start of the charging by the impedance of the second phase to an amount of current obtained by uniformly distributing the total amount of supplied charge.

The controller 130 may be configured to set an intermediate value among voltage values measured before the start of charging for each phase as a reference value for calculating the amount of charge. In other words, it can be seen that the charge amounts of the a-phase and the c-phase can be calculated based on the voltage value of the b-phase in the above equation 2. Accordingly, the controller 130 may be configured to adjust the amount of supplied current according to the amount of charge of each phase, thereby solving the voltage imbalance.

Hereinafter, an operation method of an OBC for a vehicle according to an exemplary embodiment of the present invention will be described in detail with reference to fig. 6. Fig. 6 is a flowchart illustrating a control method of an OBC for a vehicle according to an exemplary embodiment of the present invention. Hereinafter, it may be assumed that the OBC control device 100 for a vehicle in fig. 1 performs the process of fig. 6. Further, in the description of fig. 6, the operations described as being performed by the device may be understood as being operated by the controller 130 of the OBC control device 100 for a vehicle.

Referring to fig. 6, at S101, the device may be configured to measure individual voltages of the phases of a three-phase OBC 200 before starting charging. In particular, the apparatus may be configured to measure the individual voltages of the phases at the positions D1, D2, or D3 of fig. 1. The voltage of each phase is Va1, Vb1 or Vc 1. At S102, the apparatus may be configured to determine a degree of voltage unbalance of each phase using the measured difference between the voltages of the three phases. When the voltages Va1, Vb1, and Vc1 of the three phases are 210V, 220V, and 230V, respectively, the device may be configured to determine that an imbalance of 10V occurs because the voltage of the first phase is 10V smaller than the voltage of the second phase based on the voltage (210V) of the second phase (intermediate value), and because the voltage of the third phase is 10V larger than the voltage of the second phase.

At S103, the device may be configured to measure three-phase voltages while equally increasing the current supplied to each phase of the OBC. At S104, the device may be configured to calculate a voltage drop value using the voltage of each phase measured after increasing the current supplied to the OBC and the voltage of each phase measured at S101, and may be configured to measure a phase difference between the voltage and the current.

For example, when the voltage of each phase after increasing the current supplied to the OBC is Va2, Vb2, or Vc2, the voltage drop value of each phase according to the increase in the current supplied to the OBC may be a value obtained by: the voltage values Va2, Vb2 and Vc2 after the current supplied to the OBC is adjusted are subtracted from the voltage values Va1, Vb1 and Vc1 before the start of charging. Specifically, the position for measuring the phase difference between the voltage and the current may be D1, D2, or D3 of fig. 1.

Further, at S105, the apparatus may be configured to calculate impedances Za, Zb, or Zc of the phases using the voltage drop values of the phases and the phase differences between the voltages and the currents, thereby calculating the impedance unbalance. Specifically, the impedances Za, Zb, or Zc of the respective phases may be calculated using the above equation 1, and the impedance unbalance degree of the respective phases, which is the difference between the impedance values of the three phases, may be calculated. At S106, the apparatus may be configured to calculate the amount of charge to be supplied for charging using equation 2 above based on the three-phase voltages Va, Vb1, or Vc1 and the three-phase impedances Za, Zb, or Zc before starting charging. Specifically, the apparatus may be configured to calculate the three-phase charge amount as a value inversely proportional to the three-phase impedance.

For example, assuming that the voltage and impedance of the a-phase among the three phases are 210V and Za, the voltage and impedance of the b-phase among the three phases are 220V and Zb, and the voltage and impedance of the c-phase among the three phases are 230V and Zc, and charging is performed with a power of 6.6Kw, when the power is equally distributed to each of the a, b, or c-phases, each phase should supply 2.2Kw (═ 220V × 10A). However, when unbalance of each phase occurs, the apparatus may be configured to calculate a charged amount of each phase for power balance based on a predetermined reference value or an intermediate value (for example, 220V) among voltage values of three phases before each phase starts to be charged.

The apparatus may be configured to calculate a value obtained by subtracting a value obtained by dividing a voltage (210V) of the a-phase by an impedance Za of the a-phase from an amount of current distributed in equilibrium, which is an amount of current supplied to each phase in an ideal state, as the amount of charge of the a-phase, and may be configured to calculate the amount of charge supplied to the phase b or the phase c. Specifically, the charge amount of the phase where the voltage is low and the impedance is high may be calculated to be relatively low. For example, when charging is performed at an operating power of 10Kw, it may be allocated to a-phase 3Kw, b-phase 4.5Kw, and c-phase 2.5 Kw.

At S107, the device may be configured to differently supply the amount of supplied current according to the calculated amount of charge of each phase, thereby performing charging while solving the voltage imbalance. Accordingly, exemplary embodiments of the present invention may improve stability of each phase power and may perform charging when each phase power of an OBC using three-phase power is unbalanced, thereby preventing a plurality of devices (e.g., a three-phase power transformer, a load group, etc.) of a power supply from being damaged due to ignition.

Thus, the operations of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in a hardware or software module executed by a controller, or in a combination of the two. A software module may reside on a storage medium (i.e., memory and/or storage device) such as RAM, flash memory, ROM memory, EPROM, EEPROM, registers, hard disk, a removable disk, and a CD-ROM.

An exemplary storage medium may be coupled to the controller, and the controller may read information output from the storage medium and may record the information in the storage medium. Alternatively, the storage medium may be integrated with the controller. The controller and the storage medium may reside in an Application Specific Integrated Circuit (ASIC). The ASIC may reside in a user terminal. In other instances, the controller and the storage medium may reside as separate components in a user terminal.

The present technology improves safety of power used by calculating a three-phase unbalance degree when three-phase power of a three-phase OBC is charged in an unbalanced state, and differently supplying power consumed by each phase to solve the unbalance. In addition, various effects directly or indirectly determined by the present invention can be provided.

In the foregoing, although the present invention has been described with reference to the exemplary embodiments and the accompanying drawings, the present invention is not limited thereto, and various changes and modifications may be made by those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention as claimed in the appended claims.

Accordingly, the exemplary embodiments of the present invention are provided to explain the spirit and scope of the present invention and not to limit the spirit and scope of the present invention, so that the spirit and scope of the present invention are not limited by the exemplary embodiments. The scope of the invention should be construed based on the appended claims, and all technical ideas within the range equivalent to the claims should be included in the scope of the invention.