Cooling control system and method for an on-board charger of a plug-in vehicle

Abstract

A cooling control system and method for an on-board charger of a plug-in vehicle, when the temperature of the on-board charger installed in the plug-in vehicle is equal to or higher than the overheating prevention temperature, drives an electric water pump using a cooling control map. When the temperature of the on-board charger is lower than the overheating prevention temperature, the cooling control system and method determine to enter an optimal cooling control mode to cool the on-board charger to a temperature at which the charging operation efficiency is maximized. As a result, the on-board charger is cooled, and the standard charging efficiency and charge-depleted fuel economy of the plug-in vehicle are maximized.

Description

Technical Field

[0001] The present invention relates to a cooling control system and method for an on-board charger of a plug-in vehicle. More specifically, the present invention relates to a cooling control system and method for an on-board charger of an environmentally friendly vehicle. The system and method are used to cool an on-board charger assembled in a plug-in vehicle to allow the on-board charger to charge at maximum operating efficiency, thereby improving the standard charging efficiency of the on-board charger. Background Art

[0002] A plug-in vehicle is a vehicle to which an external power source and an onboard charger are connected via a plug to charge a high-voltage battery in the vehicle. A plug-in vehicle may be primarily a hybrid vehicle or an electric vehicle equipped with a high-voltage battery.

[0003] Figure 1 A charging system and a power conversion system for a plug-in vehicle are shown.

[0004] An external alternating current (AC) power source 10 and an on-board charger (OBC) 20 mounted on a vehicle are connected to each other via a plug (not shown) for charging a plug-in vehicle.

[0005] A high voltage battery 30 to be charged and a low voltage direct current (DC) or DC-DC converter (LDC) 40 are connected to the output side of the OBC 20 .

[0006] Furthermore, an auxiliary battery 50 to be charged, an electric water pump (EWP) 60 , and other electric loads are connected to the output side of the LDC 40 .

[0007] In this example, the OBC 20 converts AC power of the external AC power source 10 into DC power and charges the high voltage battery 30 at a standard charging rate.

[0008] After obtaining DC power through conversion by the OBC 20, the LDC 40 converts the DC power into low voltage power. Then, the auxiliary battery 50 or the like used as a power source for the electrical loads is charged using the low voltage power. The electric water pump EWP 60 and other electrical loads are supplied with low voltage power.

[0009] The standard charging efficiency of the high voltage battery by using the OBC 20 is expressed by the following Formula 1. The fuel economy label of the plug-in vehicle, that is, the charge depletion (CD) fuel economy of the plug-in vehicle is expressed by the following Formula 2.

[0010] Formula 1

[0011]

[0012] Formula 2

[0013]

[0014] In equations 1 and 2, P1 represents the AC power output from the external AC power source, P2 represents the DC power output from the OBC, P3 represents the DC power charged by the high-voltage battery, P4 represents the DC power input to the LDC, P5 represents the DC power converted from the LDC to a low voltage, and η OBC Indicates the operating efficiency of OBC.

[0015] From the above equations 1 and 2, it can be seen that the standard charging efficiency and CD fuel economy of plug-in vehicles increase with the operating efficiency (η) used to charge the OBC. OBC ) increases and increases as the power consumption of the electrical load decreases.

[0016] Considering that the heat generated during charging may reduce the operating efficiency of the OBC, the OBC should be cooled to improve the efficiency of the OBC.

[0017] The coolant is circulated by the driving of the EWP 60 and flows to the OBC 20 to cool the OBC 20 .

[0018] As the driving revolutions per minute (RPM) of the EWP 60 increases, the consumed power increases. However, the coolant can be quickly circulated and flowed to the OBC, thereby quickly lowering the temperature of the OBC.

[0019] The conventional EWP control method for cooling the OBC does not consider the charging operation efficiency and power load of the OBC, etc. The conventional method only considers whether the current temperature of the OBC is equal to or greater than the temperature for preventing the OBC from overheating (hereinafter referred to as the overheating prevention temperature) by driving the EWP.

[0020] That is, the conventional method is performed by using cooling control map data in which the RPM of the EWP is set for each temperature of the OBC.

[0021] For example, Figure 2 As shown, when the temperature of the OBC reaches a first reference temperature T1 equal to or greater than a predetermined temperature, the EWP is driven to a first set RPM (A). When the temperature of the OBC reaches a second reference temperature T2, the EWP is driven to a second set RPM (B) higher than the first set RPM (A). When the temperature of the OBC reaches a third reference temperature T3, the EWP is driven to a third set RPM (C) higher than the second set RPM (B).

[0022] In addition, when the temperature of the OBC reaches the first reference temperature T1, the EWP is continuously operated until the temperature of the OBC decreases to the temperature T1-α.

[0023] As described above, according to the conventional EWP control method for cooling the OBC, the EWP is operated considering only the condition of the current temperature of the OBC without considering the charging operation efficiency and the power load of the OBC. By this method, the shortening of the life of the OBC due to the higher temperature can be prevented. However, the operating efficiency of the OBC may vary with the temperature. Therefore, the charging operation efficiency of the OBC may be reduced by the conventional control method.

[0024] In addition, as the driving RPM of the EWP increases, the cooling rate of the OBC increases. However, the power consumption (electric load) of the EWP increases rapidly in the form of a quadratic function. In particular, the temperature of the coolant gradually increases due to the heat of the OBC, so even if the RPM of the EWP increases, the cooling effect of the OBC decreases. Summary of the invention

[0025] Therefore, the present invention takes into account the above-mentioned problems arising in the prior art. The present invention aims to provide a cooling control system and method for an on-board charger of a plug-in vehicle. When the temperature of the on-board charger assembled in the plug-in vehicle is equal to or higher than the anti-overheating temperature, the system and method drive the electric water pump using a basic cooling control map. When the temperature of the on-board charger is lower than the anti-overheating temperature, the system and method further determine the entry into the optimal cooling control mode to cool the on-board charger to a temperature at which the charging operation efficiency is maximized. Therefore, the system and method can easily cool the on-board charger and maximize the standard charging efficiency and CD fuel economy of the plug-in vehicle.

[0026] In order to achieve the above-mentioned object, according to an embodiment of the present invention, a cooling control method for an on-board charger (OBC) for a plug-in vehicle is provided. The method includes determining the entry of an optimal cooling control mode for cooling the OBC to a temperature that maximizes the operating efficiency of the OBC charged by the OBC. The method also includes calculating the operating efficiency of the OBC at the current temperature. The method also includes comparing the operating efficiency of the OBC at the current temperature with the maximum operating efficiency, and determining whether the current temperature of the OBC is the maximum operating efficiency temperature of the OBC. The method also includes controlling the current temperature of the OBC to a temperature range corresponding to the maximum operating efficiency by controlling an electric water pump (EWP) to be driven, based on the result of determining whether the current temperature of the OBC is the maximum operating efficiency temperature of the OBC.

[0027] Determining entry into an optimal cooling control mode may include: receiving a standard charging relay on signal from a main controller at the OBC controller; receiving a current temperature of the OBC provided by a temperature sensor at the OBC controller; and determining entry into an optimal cooling control mode in the OBC controller based on the received current temperature.

[0028] When determining the entry of the optimal cooling control mode, the basic cooling control mode may be entered when the current temperature of the OBC is equal to or higher than the overheating prevention temperature. When the current temperature of the OBC is lower than the overheating prevention temperature, the optimal cooling control mode may be entered.

[0029] The calculation unit may calculate the operation efficiency of the OBC at the current temperature based on the temperature signal provided from the temperature sensor, the input voltage and input current signals provided from the input voltage and input current sensor, and the output voltage and output current signals provided from the output voltage and output current sensor.

[0030] The calculation unit can calculate the operating efficiency of the OBC at the current temperature by the following formula:

[0031]

[0032] The operating efficiency of the OBC at the current temperature calculated by the calculation unit may be provided to the OBC controller as data for determining entry of the optimal cooling control mode.

[0033] In determining whether the current temperature of the OBC is the maximum operating efficiency temperature of the OBC, when the operating efficiency of the OBC at the current temperature is equal to or greater than the maximum operating efficiency of the OBC as a result of comparison by the OBC controller between the operating efficiency of the OBC at the current temperature and the maximum operating efficiency of the OBC, the OBC controller may store the maximum operating efficiency temperature of the OBC as the current temperature of the OBC. The OBC controller may further store the maximum operating efficiency of the OBC as the current operating efficiency of the OBC.

[0034] When determining whether the current temperature of the OBC is the maximum operating efficiency temperature of the OBC, when, as a result of comparison by the OBC controller between the operating efficiency of the OBC at the current temperature and the maximum operating efficiency of the OBC, the operating efficiency of the OBC at the current temperature is lower than the maximum operating efficiency of the OBC, the OBC controller can control the current temperature of the OBC to a temperature range corresponding to the maximum operating efficiency of the OBC by means of switching control of an electric water pump (EWP).

[0035] Controlling the current temperature of the OBC to a temperature range corresponding to the maximum operating efficiency of the OBC may include: sending a drive command signal from the OBC controller to the motor controller to drive the EWP; driving the EWP under the control of the motor controller; controlling the current temperature of the OBC to a maximum operating efficiency temperature by means of cooling by operation of the EWP; and checking whether the current temperature of the OBC reaches the maximum operating efficiency temperature by operation of the EWP.

[0036] Controlling the current temperature of the OBC to the maximum operating efficiency temperature of the OBC may include comparing the current temperature of the OBC with a value (maximum operating efficiency temperature+hysteresis B) by the OBC controller before the OBC controller sends a drive command signal to the motor controller. Controlling the current temperature may also include: when the current temperature of the OBC is equal to the value (maximum operating efficiency temperature+B) as a result of the comparison, sending a drive command signal from the OBC controller to the motor controller to drive the EWP. Controlling the current temperature may also include: driving the EWP by the motor controller based on an optimized cooling control map that sets the RPM of the EWP for each temperature of the OBC.

[0037] Checking whether the current temperature of the OBC reaches the maximum operating efficiency temperature of the OBC may include: comparing the current temperature of the OBC with a value (maximum operating efficiency temperature-B) by the OBC controller during operation of the EWP. Checking whether the current temperature of the OBC reaches the maximum operating efficiency temperature of the OBC may also include: as a result of the comparison, closing the EWP when the current temperature of the OBC is equal to the value (maximum operating efficiency temperature-B).

[0038] In order to achieve the above object, according to another embodiment of the present invention, a cooling control system for an OBC of a plug-in vehicle is provided. The system includes: a temperature sensor for measuring the temperature of the OBC; an input voltage and input current sensor for measuring the voltage and current input to the OBC; an output voltage and output current sensor for measuring the voltage and current output from the OBC; an OBC controller for determining the entry of an optimal cooling control mode for cooling the OBC; and a calculation unit for providing the OBC controller with an operating efficiency at each temperature as data for determining the entry of the optimal cooling control mode.

[0039] The OBC controller may determine whether the temperature of the OBC is equal to or higher than the overheat prevention temperature based on the current temperature signal of the OBC provided from the temperature sensor. The OBC controller may further determine entry of an optimal cooling control mode to cool the OBC to a temperature that maximizes the operating efficiency of the OBC charging.

[0040] The calculation unit may calculate the operation efficiency of each temperature of the OBC based on the temperature signal provided from the temperature sensor, the input voltage and input current signals provided from the input voltage and input current sensors, and the output voltage and output current signals provided from the output voltage and output current sensors. The calculation unit may also provide the operation efficiency calculated for each temperature to the OBC controller as data for determining entry of the optimal cooling control mode.

[0041] The system may further include the main controller transmitting a standard charging relay ON signal to the OBC controller as a starting point for determining entry of the optimal cooling control mode.

[0042] The system may further include a motor controller that drives the EWP based on a cooling control map that sets revolutions per minute (RPM) of the EWP for each temperature of the OBC when the drive command signal is present.

[0043] The present invention provides the following effects according to the above technical solution.

[0044] According to the present invention, when the temperature of the on-board charger installed in the plug-in vehicle is lower than the overheating prevention temperature, the optimal cooling control mode is entered to cool the on-board charger to a temperature at which the operating efficiency of the on-board charger charging is maximized. Therefore, the on-board charger is easy to cool, and the standard charging efficiency and CD fuel economy of the plug-in vehicle can be maximized.

[0045] Furthermore, when the temperature of the on-board charger is equal to or higher than the overheating prevention temperature, the on-board charger can be easily protected from overheating by quickly increasing the RPM of the electric water pump using the basic cooling control map. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0047] Figure 1 is a configuration diagram showing a charging system and a power conversion system for a plug-in vehicle according to the prior art;

[0048] Figure 2 is a graph showing a method of controlling an electric water pump for cooling an on-board charger according to the prior art;

[0049] Figure 3 is a system configuration diagram of a cooling control method for an on-board charger for a plug-in vehicle according to the present invention; and

[0050] Figure 4 is a flowchart illustrating a cooling control method of an on-board charger for a plug-in vehicle according to the present invention. DETAILED DESCRIPTION

[0051] Hereinafter, various embodiments of the present invention are described in detail with reference to the accompanying drawings.

[0052] Figure 3 2 is a system configuration diagram of a cooling control method of an on-board charger (OBC) for a plug-in vehicle according to the present invention, wherein reference numeral 20 denotes an OBC equipped in the plug-in vehicle.

[0053] The OBC 20 includes a power circuit 21 that converts alternating current (AC) power supplied from an external AC power source into direct current (DC) power. The OBC 20 also includes a temperature sensor 23 for measuring the temperature of the OBC 20. The OBC 20 also includes an input voltage and input current sensor 22 for measuring a voltage and a current input to the OBC 20, and an output voltage and output current sensor 24 for measuring a voltage and a current output from the OBC 20.

[0054] In addition, the OBC 20 may further include a calculation unit 25 and an OBC controller 26 .

[0055] The OBC controller 26 determines whether the current temperature of the OBC 20 is equal to or higher than the overheating prevention temperature based on the current temperature signal of the OBC 20 provided from the temperature sensor 23. In particular, the OBC controller 26 determines whether to enter the optimal cooling control mode to cool the OBC 20 to a temperature at which the operating efficiency of the OBC 20 charging is maximized.

[0056] The calculation unit 25 calculates the operation efficiency value for each temperature of the OBC 20 based on the temperature signal provided from the temperature sensor 23, the input voltage and input current signals provided from the input voltage and input current sensor 22, and the output voltage and output current signals provided from the output voltage and output current sensor 24. Then, the calculation unit 25 provides the operation efficiency value for each temperature calculated as above to the OBC controller 26 as data for determining whether to enter the optimal cooling control mode.

[0057] A main controller 70 such as a hybrid control unit (HCU) and a motor controller 80 such as a motor control unit (MCU) are connected to the input side and the output side of the OBC controller 26, respectively.

[0058] The main controller 70 sends a standard charging relay ON signal to the OBC controller 26 as a starting point for determining whether to enter the optimum cooling control mode.

[0059] When having a driving command signal of the OBC controller 26 , the motor controller 80 drives the electric water pump (EWP) 60 based on a cooling control map that sets the revolutions per minute (RPM) of the EWP 60 for each temperature of the OBC 20 .

[0060] Hereinafter, a cooling control method of an OBC based on the above-mentioned configuration according to the present invention is described.

[0061] Figure 4 Detailed description is given in FIG. 4 and FIG. 5 is a flowchart of a cooling control method for an OBC of a plug-in vehicle according to the present invention.

[0062] The OBC controller 26 determines whether the plug-in vehicle is in a standard charging state ( S101 ).

[0063] That is, when the OBC controller 26 receives and confirms the standard charging relay on signal transmitted from the main controller 70 , the OBC controller 26 recognizes that the plug-in vehicle is in the standard charging state.

[0064] Then, when the OBC controller 26 recognizes that the plug-in vehicle is in the standard charging state, the OBC controller 26 determines whether to enter the optimal cooling control mode. As a starting step, the OBC controller 26 compares the current temperature of the OBC 20 with the overheating prevention temperature (S102).

[0065] That is, when the temperature signal of the on-vehicle charger measured by the temperature sensor 23 is transmitted to the OBC controller 26 , the OBC controller 26 determines whether the current temperature of the OBC 20 is equal to or higher than the overheating prevention temperature.

[0066] When the current temperature of the OBC is equal to or higher than the overheat prevention temperature A, the OBC controller 26 enters the basic cooling control mode (S103). The OBC controller 26 drives the EWP 60 based on the basic cooling control map data that sets the RPM of the EWP 60 for each temperature of the OBC 20 (S104 and S105).

[0067] More specifically, when the current temperature of the on-board charger is equal to or higher than the overheat prevention temperature A, the OBC controller 26 transmits a command signal to the motor controller 80 that drives the EWP 60. Accordingly, the motor controller 80 drives the EWP 60 based on the basic cooling control map data that sets the RPM of the EWP 60 for each temperature of the OBC 20.

[0068] For example, as referenced above Figure 2As described above, when the temperature of the OBC 20 reaches the first reference temperature T1 equal to or greater than the predetermined temperature, the motor controller 80 controls the driving of the EWP 60 based on the basic cooling control map data that the EWP 60 is driven to the first set RPM (A). When the temperature of the OBC 20 reaches the second reference temperature T2, the EWP 60 is driven to the second set RPM (B) higher than the first set RPM (A). When the temperature of the OBC 20 reaches the third reference temperature T3, the EWP 60 is driven to the third set RPM (C) higher than the second set RPM (B).

[0069] Therefore, when the temperature of the OBC 20 is equal to or higher than the overheat prevention temperature A, the RPM of the EWP 60 increases according to the temperature so that the coolant quickly circulates to the OBC, thereby protecting the OBC from overheating and preventing the life of the OBC from being shortened due to overheating.

[0070] In contrast, when it is determined in S102 that the current temperature of the OBC 20 is lower than the overheat prevention temperature A, the OBC controller 26 enters an optimal cooling control mode ( S106 ) for cooling the OBC to a temperature that maximizes the operating efficiency of the OBC, taking into account the charging operating efficiency and the power load at each temperature of the OBC.

[0071] After entering the optimal cooling control mode, the OBC controller 26 stores the current temperature of the OBC 20 and calculates the operating efficiency of the OBC at the current temperature ( S107 ).

[0072] More specifically, the OBC controller 26 stores the current temperature of the OBC 20 transmitted from the temperature sensor 23. The calculation unit 25 calculates the operation efficiency based on the temperature signal provided from the temperature sensor 23, the input voltage and input current signals provided from the input voltage and input current sensor 22, and the output voltage and output current signals provided from the output voltage and output current sensor 24.

[0073] Preferably, the calculation unit 25 calculates the operating efficiency of the OBC 20 at the current temperature by the following equation 3.

[0074] Formula 3

[0075]

[0076] In Equation 3, the power factor is replaced by 0.99.

[0077] The operation efficiency for each temperature of the OBC 20 calculated by the calculation unit 25 is provided to the OBC controller 26 as data for determining whether to enter the optimum cooling control mode.

[0078] In addition, after the operating efficiency of the OBC 20 at the current temperature calculated by the calculation unit 25 is provided to the OBC controller 26, the operating efficiency of the OBC is used as data for comparing with the maximum operating efficiency and determining whether the current temperature of the OBC is a temperature corresponding to the maximum operating efficiency of the OBC.

[0079] Next, the OBC controller 26 compares the current operating efficiency of the OBC 20 transmitted from the calculation unit 25 , that is, the operating efficiency of the OBC at the current temperature, with the maximum operating efficiency.

[0080] That is, the OBC controller 26 compares the operating efficiency of the OBC 20 at the current temperature with the maximum operating efficiency of the OBC, which has been set when the OBC product is manufactured.

[0081] According to the result of determining whether the current temperature of the OBC 20 is the temperature corresponding to the maximum operating efficiency of the OBC, or in other words, according to the result of comparing the operating efficiency of the OBC at the current temperature with the maximum operating efficiency of the OBC, the step of controlling the current temperature of the OBC to the temperature corresponding to the maximum operating efficiency can be performed by controlling the EWP 60 to be driven (hereinafter referred to as driving control for the EWP).

[0082] In this embodiment, as a result of the comparison in step S108, if the operating efficiency of the OBC 20 at the current temperature is equal to or greater than the maximum operating efficiency of the OBC, the temperature corresponding to the maximum operating efficiency of the OBC is stored as the current temperature of the OBC, and the maximum operating efficiency of the OBC is stored as the current operating efficiency of the OBC (S109).

[0083] More specifically, as a result of the comparison in S108, if the operating efficiency of the OBC 20 at the current temperature is equal to or greater than the maximum operating efficiency of the OBC, the OBC controller 26 determines that the current temperature of the OBC is a temperature corresponding to the maximum operating efficiency of the OBC (hereinafter referred to as the maximum operating efficiency temperature), and stores the maximum operating efficiency temperature of the OBC as the current temperature of the OBC. At the same time, the OBC controller 26 determines that the current operating efficiency of the OBC 20 is an efficiency corresponding to the maximum operating efficiency of the OBC, and stores the maximum operating efficiency of the OBC as the current operating efficiency of the OBC.

[0084] In this way, through steps S108 and S109, the temperature of the OBC 20 corresponding to the maximum operating efficiency of the OBC can be found, and the OBC is controlled to be cooled to a temperature range corresponding to the maximum operating efficiency of the OBC.

[0085] In contrast, as a result of the comparison in S108 , if the current temperature of the OBC 20 is lower than the maximum operating efficiency temperature, the temperature of the OBC is controlled to the maximum operating efficiency temperature by means of the drive control for the EWP 60 .

[0086] That is, when it is determined in S108 that the current operating efficiency of the OBC is lower than the maximum operating efficiency of the OBC 20 , the OBC controller 26 performs cooling control of controlling the temperature of the OBC to a temperature range corresponding to the maximum operating efficiency by means of the opening-closing control of the EWP 60 .

[0087] Therefore, when it is determined that the operating efficiency of the OBC 20 at the current temperature is lower than the maximum operating efficiency of the OBC, the OBC controller 26 enters a control mode for operating the EWP 60 ( S110 ).

[0088] In this embodiment, when it is determined that the current operating efficiency of the OBC 20 is lower than the maximum operating efficiency of the OBC, the OBC controller 26 controls to drive the EWP 60 so that the OBC performs a standard charging operation at the maximum operating efficiency temperature.

[0089] More specifically, when it is determined that the current operating efficiency of the OBC 20 is lower than the maximum operating efficiency of the OBC, the OBC controller 26 sends a drive command signal to the motor controller 80 to drive the EWP 60 so that the current temperature of the OBC becomes the maximum operating efficiency temperature. Therefore, the EWP 60 is driven under the control of the motor controller 80 to cool the OBC 20 by means of coolant circulation, so that the current temperature of the OBC can be easily controlled to the maximum operating efficiency temperature stored in step S109.

[0090] When controlling the current temperature of the OBC 20 to the maximum operation efficiency temperature, it is preferable to set hysteresis B to have a control range as shown in the following Equation 4 so that the current temperature of the OBC is easily controlled to the maximum operation efficiency temperature.

[0091] Formula 4

[0092] (maximum operating efficiency temperature - B) < (current temperature) < (maximum operating efficiency temperature + B)

[0093] To this end, before the OBC controller 26 transmits a drive command signal to the motor controller 80 to drive the EWP 60 , the OBC controller 26 compares the current temperature of the OBC 20 with (maximum operating efficiency temperature+B) ( S111 ).

[0094] As a result of the comparison, when the current temperature of the OBC 20 is equal to the value (maximum operating efficiency temperature+B), the OBC controller 26 sends a drive command signal to the motor controller 80 to drive the EWP 60 so as to reduce the current temperature of the OBC to the maximum operating efficiency temperature.

[0095] Then, the motor controller 80 performs control based on the optimum cooling control map that sets the RPM of the EWP 60 for each temperature of the OBC 20 to drive the EWP 60 ( S112 and S113 ).

[0096] Therefore, the EWP 60 is operated, thereby cooling the OBC 20 through the coolant circulation. Thus, the current temperature of the OBC 20 can be easily controlled to the maximum operating efficiency temperature stored in S109.

[0097] Thereafter, in order to check whether the current temperature of the OBC 20 reaches the maximum operating efficiency temperature through the operation of the EWP 60 , the OBC controller 26 compares the current temperature of the OBC with a value (maximum operating efficiency temperature-B) during the operation of the EWP 60 ( S114 ).

[0098] When the current temperature of the OBC 20 is equal to the value (maximum operating efficiency temperature-B) as a result of the comparison, the EWP 80 is turned off (S115).

[0099] That is, when the current temperature of the OBC 20 is equal to the value (maximum operating efficiency temperature-B), the OBC controller 26 sends a command signal to the motor controller 80 to stop the EWP 60 so that the current temperature of the OBC does not further decrease.

[0100] As described above, the current temperature of the OBC 20 is controlled to the maximum operating efficiency temperature, preferably, to a range between a value (maximum operating efficiency temperature - B) and a value (maximum operating efficiency temperature + B). Therefore, not only can the OBC 20 be easily cooled, but the OBC can also maintain the maximum operating efficiency of charging, thereby maximizing the standard charging efficiency and CD fuel economy.

[0101] During the step of controlling the current temperature of the OBC 20 to the maximum operating efficiency temperature by the operation of the EWP 60, regardless of the operation of the electric water pump, when it is determined that the temperature of the OBC increases to be higher than the overheating prevention temperature due to external factors (S116), the basic cooling control mode (S103) is entered to quickly cool the OBC as described above.

Claims

1. A cooling control method for an on-board charger (OBC) of a plug-in vehicle, the method comprising the following steps: Determining to enter an optimal cooling control mode to cool the OBC to a temperature that maximizes the OBC operating efficiency of the OBC charging, wherein in the step of determining to enter the optimal cooling control mode: when the current temperature of the OBC is lower than the overheating prevention temperature, entering the optimal cooling control mode; Calculating the operating efficiency of the OBC at the current temperature; comparing the operating efficiency of the OBC at a current temperature with a maximum operating efficiency, and determining whether the current temperature of the OBC is a maximum operating efficiency temperature of the OBC; and According to the result of determining whether the current temperature of the OBC is the maximum operating efficiency temperature of the OBC, the current temperature of the OBC is controlled to a temperature range corresponding to the maximum operating efficiency of (maximum operating efficiency temperature - hysteresis B) < current temperature < (maximum operating efficiency temperature + hysteresis B) by controlling the electric water pump EWP to be driven, Wherein, in the step of determining whether the current temperature of the OBC is the maximum operating efficiency temperature of the OBC, when, as a result of a comparison between the operating efficiency of the OBC at the current temperature and the maximum operating efficiency of the OBC performed by the OBC controller, the operating efficiency of the OBC at the current temperature is equal to or greater than the maximum operating efficiency of the OBC, the OBC controller stores the maximum operating efficiency temperature of the OBC as the current temperature of the OBC.

2. The method according to claim 1, wherein: The step of determining to enter the optimal cooling control mode comprises the following steps: receiving a standard charging relay on signal from a main controller on the OBC controller; receiving a current temperature of the OBC provided by a temperature sensor on the OBC controller; and According to the received current temperature, it is determined in the OBC controller whether to enter the optimal cooling control mode.

3. The method according to claim 2, wherein: In the step of determining to enter the optimal cooling control mode, When the current temperature of the OBC is equal to or higher than the overheating prevention temperature, the basic cooling control mode is entered. The basic cooling control mode drives the EWP based on basic cooling control map data in which RPM of the EWP is set for each temperature of the OBC.

4. The method according to claim 1, wherein: The operation efficiency of the OBC at the current temperature is calculated by a calculation unit based on a temperature signal provided by a temperature sensor, input voltage and input current signals provided by an input voltage and input current sensor, and output voltage and output current signals provided by an output voltage and output current sensor.

5. The method according to claim 4, wherein: The calculation unit calculates the operating efficiency of the OBC at the current temperature by the following formula:

6. The method according to claim 4, wherein: The operation efficiency of the OBC at the current temperature calculated by the calculation unit is provided to the OBC controller as data for determining whether to enter the optimum cooling control mode.

7. The method according to claim 1, wherein: In the step of determining whether the current temperature of the OBC is the maximum operating efficiency temperature of the OBC, According to a result of a comparison between the operating efficiency of the OBC at a current temperature and the maximum operating efficiency of the OBC performed by the OBC controller, when the operating efficiency of the OBC at the current temperature is equal to or greater than the maximum operating efficiency of the OBC, the OBC controller stores the maximum operating efficiency temperature of the OBC as the current temperature of the OBC, and stores the maximum operating efficiency of the OBC as the current operating efficiency of the OBC.

8. The method according to claim 1, wherein: In the step of determining whether the current temperature of the OBC is the maximum operating efficiency temperature of the OBC, According to a result of comparison between the operating efficiency of the OBC at a current temperature and the maximum operating efficiency of the OBC performed by the OBC controller, when the operating efficiency of the OBC at the current temperature is lower than the maximum operating efficiency of the OBC, the OBC controller controls the current temperature of the OBC to a temperature range corresponding to the maximum operating efficiency of the OBC by means of opening-closing control of the EWP.

9. The method according to claim 8, wherein: The step of controlling the current temperature of the OBC to a temperature range corresponding to the maximum operating efficiency of the OBC comprises the following steps: sending a drive command signal from the OBC controller to a motor controller to drive the EWP; driving the EWP under control of the motor controller; Controlling the current temperature of the OBC to the maximum operating efficiency temperature by operating the EWP for cooling; and It is checked whether the current temperature of the OBC reaches the maximum operating efficiency temperature through the operation of the EWP.

10. The method according to claim 9, wherein: The step of controlling the current temperature of the OBC to the maximum operating efficiency temperature of the OBC comprises the following steps: Before the OBC controller sends a drive command signal to the motor controller, the OBC controller compares the current temperature of the OBC with the value "maximum operating efficiency temperature + hysteresis B"; According to the comparison result, when the current temperature of the OBC is equal to the value "maximum operating efficiency temperature+hysteresis B", the drive command signal is sent from the OBC controller to the motor controller to drive the EWP; and The EWP is driven by the motor controller based on an optimum cooling control map that sets the RPM of the EWP for each temperature of the OBC.

11. The method according to claim 9, wherein: The step of checking whether the current temperature of the OBC reaches the maximum operating efficiency temperature of the OBC comprises the following steps: During operation of the EWP, the current temperature of the OBC is compared by the OBC controller with a value of "maximum operating efficiency temperature - hysteresis B"; and According to the comparison result, when the current temperature of the OBC is equal to the value "maximum operating efficiency temperature-hysteresis B", the EWP is closed.

12. A cooling control system for an on-board charger (OBC) for a plug-in vehicle for executing the cooling control method according to any one of claims 1 to 11, the system comprising: A temperature sensor, used to measure the temperature of the OBC; Input voltage and input current sensors, used to measure the voltage and current input to the OBC; Output voltage and output current sensors for measuring voltage and current output from the OBC; An OBC controller, configured to determine whether to enter an optimal cooling control mode for cooling the OBC; and A calculation unit is used to provide the OBC controller with the operation efficiency of the OBC for each temperature as data for determining whether to enter an optimal cooling control mode.

13. The system according to claim 12, wherein: The OBC controller determines whether the temperature of the OBC is equal to or higher than an overheating prevention temperature based on a current temperature signal of the OBC provided by the temperature sensor, and determines whether to enter an optimal cooling control mode for cooling the OBC to a temperature that maximizes operating efficiency of charging the OBC.

14. The system according to claim 12, wherein: The calculation unit calculates the operating efficiency of the OBC at each temperature based on the temperature signal provided from the temperature sensor, the input voltage and input current signals provided by the input voltage and input current sensors, and the output voltage and output current signals provided by the output voltage and output current sensors, and provides the calculated operating efficiency at each temperature to the OBC controller as data for determining whether to enter the optimal cooling control mode.

15. The system of claim 12, further comprising: The main controller is used to send a standard charging relay turn-on signal to the OBC controller as a starting point for determining whether to enter the optimal cooling control mode.

16. The system of claim 12, further comprising: A motor controller for driving the electric water pump EWP based on a cooling control map that sets the RPM of the EWP for each temperature of the OBC when there is a drive command signal of the OBC controller.

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