Control method for improving charging efficiency of vehicle-mounted charger, vehicle controller and electric vehicle

Abstract

The invention provides a control method for improving the charging efficiency of a vehicle-mounted charger, a vehicle controller and an electric vehicle, and is applied to the field of power supply and distribution of electric vehicles. The control method is used for adjusting the magnitude of direct current output by a vehicle-mounted charger according to the impedance of a transmission line so as to improve the charging efficiency of the vehicle-mounted charger, and comprises the following steps: after an alternating current charging pile is connected with an electric vehicle, receiving a charging request signal sent by the vehicle-mounted charger, the charging request signal indicates that the connection between the vehicle-mounted charger and the AC charging pile is completed; after the charging request signal is received, the vehicle-mounted charger is controlled to receive alternating current output by the alternating current charging pile and convert the alternating current into direct current; in the process that the vehicle-mounted charger charges the power battery, the magnitude of the direct current output by the vehicle-mounted charger is controlled according to the impedance of the transmission line, and the larger the impedance of the transmission line is, the smaller the direct current output by the vehicle-mounted charger is. Therefore, the comprehensive charging efficiency of the vehicle-mounted charger is improved.

Description

Technical Field

[0001] The present application relates to the field of power supply and distribution for electric vehicles, and in particular to a control method for improving the charging efficiency of an on-board charger, a vehicle controller, and an electric vehicle. Background Art

[0002] With the continuous development of the electric vehicle industry, electric vehicles are usually charged through on-board chargers (OBCs) and charging piles. Some charging piles require transmission lines tens or even hundreds of meters long to connect to the distribution box. Therefore, when charging electric vehicles on a daily basis, there is some power loss in the transmission line between the distribution box and the charging pile, resulting in low overall charging efficiency of the on-board charger (OBC), and the user is responsible for the power loss of the transmission line. Summary of the Invention

[0003] Embodiments of the present application provide a control method, a vehicle controller, and an electric vehicle for improving the charging efficiency of an on-board charger, which adjusts the magnitude of the direct current output by the on-board charger according to the impedance of a transmission line to improve the charging efficiency of the on-board charger.

[0004] In a first aspect, an embodiment of the present application provides a control method for improving the charging efficiency of an on-board charger, wherein the on-board charger is used to receive alternating current (AC) power output from an AC charging pile through a transmission line and convert the AC power into DC power to charge a power battery. The control method is used to adjust the magnitude of the DC power output by the on-board charger according to the impedance of the transmission line to improve the charging efficiency of the on-board charger. The control method includes: after the plug of the AC charging pile and the charging socket of the electric vehicle are connected, receiving a charging request signal sent by the on-board charger, the charging request signal being used to indicate that the connection between the on-board charger and the AC charging pile is complete; after receiving the charging request signal, controlling the on-board charger to receive the AC power output from the AC charging pile and converting the AC power into DC power to charge the power battery; during the process of the on-board charger charging the power battery, controlling the magnitude of the DC power output by the on-board charger according to the impedance of the transmission line, wherein the greater the impedance of the transmission line, the smaller the DC power output by the on-board charger is controlled.

[0005] According to the analysis: under the condition of constant DC power, the greater the impedance of the transmission line, the more power is consumed on the transmission line, and the lower the overall charging efficiency.

[0006] In this embodiment, the connection between the on-board charger and the AC charging pile is detected by automatically detecting a charging request signal. After confirming that the connection between the on-board charger and the AC charging pile is complete, the on-board charger is controlled to convert the AC power output from the AC charging pile into DC power to charge the power battery, thereby preventing damage to the electric vehicle's hardware and software due to poor contact, excessive output voltage from the AC charging pile, etc. During the process of charging the power battery, the amount of DC power output by the on-board charger is controlled according to the impedance of the transmission line. This allows for flexible control of the amount of DC power output by the on-board charger under different impedance levels. The greater the impedance of the transmission line, the smaller the DC power output by the on-board charger. This reduces the amount of power consumed in the transmission line during the process of charging the power battery, improves the overall charging efficiency of the on-board charger, and saves power consumption and electricity costs.

[0007] In an embodiment of the first aspect, the control method further includes: when the impedance of the transmission line is a first impedance, controlling the DC power output by the on-board charger to be a first DC power; when the impedance of the transmission line is a second impedance greater than the first impedance, controlling the DC power output by the on-board charger to be a second DC power less than the first DC power.

[0008] In this embodiment, when the on-board charger is charging the power battery, the on-board charger is controlled to output a larger first DC power when the impedance of the transmission line is a smaller first impedance, and is controlled to output a smaller second DC power when the impedance of the transmission line is a larger second impedance. The DC power output by the on-board charger is flexibly controlled under different impedance sizes, thereby reducing the amount of power consumed on the transmission line during the process of charging the power battery by the on-board charger, improving the overall charging efficiency of the on-board charger, and saving power consumption and electricity costs.

[0009] In an embodiment of the first aspect, the control method further includes: during the process of the on-board charger charging the power battery, controlling the magnitude of the direct current output by the on-board charger according to a preset charging time set by a user.

[0010] In this embodiment, the preset charging time is set by the user, and the preset charging time can reflect the user's charging needs. By controlling the amount of DC power output by the on-board charger according to the preset charging time, the amount of DC power output by the on-board charger can be flexibly controlled under different preset charging time values, so as to fully charge the power battery within the preset charging time, thereby meeting the user's charging needs.

[0011] In an embodiment of the first aspect, the control method further includes: the longer the preset charging time is, the smaller the DC power output by the on-board charger is controlled.

[0012] The longer the preset charging time is, the weaker the user's demand for high charging power and fast full charging is, and the smaller the DC power output of the on-board charger can be to fully charge the power battery within the preset charging time.

[0013] According to the analysis: when the impedance of the transmission line is constant, the smaller the DC power, the less power is consumed on the transmission line, and the greater the overall charging efficiency.

[0014] In this embodiment, when the on-board charger is charging the power battery, the longer the preset charging time is, that is, the weaker the user's demand for high charging power and fast full charging, the DC power output of the on-board charger is controlled to be smaller, so that the power battery can be fully charged within the preset charging time while reducing the power consumption on the transmission line, thereby meeting the user's charging needs while improving the overall charging efficiency of the on-board charger.

[0015] In an embodiment of the first aspect, the control method further includes: at a first moment, the preset charging time is a first preset time, and the DC power output by the on-board charger is controlled to be a third DC power; at a second moment after the first moment, the preset charging time is a second preset time greater than the first preset time, and during the process of the on-board charger being used to charge the power battery, the DC power output by the on-board charger is controlled to be reduced to a fourth DC power less than the third DC power.

[0016] In this embodiment, during the process of the on-board charger charging the power battery, after the preset charging time is changed from the first preset time to a larger second preset time, the DC power output by the on-board charger is controlled to be reduced to a fourth DC power that is smaller than the third DC power, so that the DC power output by the on-board charger is more in line with the user's weaker demand for high charging power and fast full charging after the change. In the scenario involving the change of the preset charging time, the power battery can be fully charged within the changed preset charging time while the overall charging efficiency of the on-board charger is improved.

[0017] In an embodiment of the first aspect, the control method further includes: when the preset charging time is greater than or equal to a preset value, controlling the DC power output by the on-board charger not to decrease as the preset charging time increases.

[0018] The preset value refers to the time it takes for the on-board charger to output direct current with high comprehensive charging efficiency to fully charge the power battery when supplying power to the low-voltage load in the electric vehicle.

[0019] In this embodiment, during the process of the on-board charger charging the power battery, by setting a preset value, when the preset charging time is greater than or equal to the preset value, the DC power output by the on-board charger is controlled not to decrease as the preset charging time increases. This comprehensively considers the scenario where the on-board charger simultaneously supplies power to the low-voltage load in the electric vehicle during the process of charging the power battery, and limits the DC power output of the on-board charger to not change with the change of the preset charging time. This avoids the situation where the on-board charger cannot meet the requirements of charging the power battery with high comprehensive charging efficiency while supplying power to the low-voltage load due to too little DC power, thereby ensuring the high comprehensive charging efficiency of the on-board charger.

[0020] In an embodiment of the first aspect, the control method further includes: during the process of the on-board charger charging the power battery, controlling the direct current output by the on-board charger to be greater than or equal to a preset current.

[0021] Among them, the preset current is the minimum DC current allowed to fully charge the power battery with high comprehensive charging efficiency when powering the low-voltage load in the electric vehicle. It can be considered as the DC current corresponding to the preset charging time being the preset value.

[0022] In this embodiment, during the process of the on-board charger charging the power battery, comprehensive consideration is given to the scenario of simultaneously powering the low-voltage loads in the electric vehicle while the on-board charger is charging the power battery. By controlling the DC power output by the on-board charger to be greater than or equal to the preset current, the charging current output by the on-board charger is limited to not be too small, thereby avoiding the situation where the on-board charger cannot meet the requirements of charging the power battery with high comprehensive charging efficiency while powering the low-voltage loads due to the charging current being too small, thereby ensuring the high comprehensive charging efficiency of the on-board charger.

[0023] In an embodiment of the first aspect, the control method further includes: when the on-board charger charges the power battery and supplies power to the load of the electric vehicle at the same time, controlling the on-board charger to output DC power greater than the power supplied to the load of the electric vehicle.

[0024] In this embodiment, while the on-board charger is charging the power battery and supplying power to the load of the electric vehicle at the same time, by controlling the power of the DC power output by the on-board charger to be greater than the power supplying power to the load of the electric vehicle, the on-board charger can effectively charge the power battery while supplying power to the load.

[0025] In an embodiment of the first aspect, the control method further includes: when the on-board charger is charging the power battery, the longer the length of the transmission line is, the smaller the DC power output by the on-board charger is controlled.

[0026] Among them, the length of the transmission line determines the impedance of the transmission line.

[0027] In this embodiment, when the on-board charger is charging the power battery, the longer the transmission line is, the smaller the DC power output by the on-board charger is controlled, thereby reducing the power loss on the transmission line and improving the overall charging efficiency of the on-board charger.

[0028] In an embodiment of the first aspect, the control method further includes: when the on-board charger is charging the power battery, the higher the ambient temperature is, the smaller the DC power output by the on-board charger is controlled.

[0029] Among them, the impedance of the transmission line will increase with the increase of ambient temperature.

[0030] In this embodiment, when the on-board charger is charging the power battery, the higher the ambient temperature is, the smaller the DC power output by the on-board charger is controlled to be, thereby reducing the power loss on the transmission line and improving the overall charging efficiency of the on-board charger.

[0031] In an embodiment of the first aspect, in response to receiving a trigger instruction, the on-board charger is controlled to output direct current according to information indicated by the trigger instruction.

[0032] In this embodiment, when the on-board charger is used to charge the power battery, the on-board charger is controlled to output direct current in response to receiving a trigger instruction and according to the information indicated by the trigger instruction, thereby realizing automatic detection of instructions and control of output current, thereby improving the control speed and response speed of the on-board charger.

[0033] In a second aspect, an embodiment of the present application provides a vehicle controller, which is used to: receive a charging request signal sent by an on-board charger after the plug of the AC charging pile is connected to the charging socket of the electric vehicle, wherein the charging request signal is used to indicate that the connection between the on-board charger and the AC charging pile is complete; after receiving the charging request signal, control the on-board charger to receive the AC power output by the AC charging pile and convert the AC power into DC power to charge the power battery; during the process of the on-board charger charging the power battery, control the size of the DC power output by the on-board charger according to the impedance of the transmission line, wherein the greater the impedance of the transmission line, the smaller the DC power output by the on-board charger is controlled.

[0034] In a third aspect, an embodiment of the present application provides an electric vehicle, which includes an on-board charger, a vehicle controller and a power battery. The on-board charger is used to receive AC power output from an AC charging pile through a transmission line and convert the AC power into DC power to charge the power battery.

[0035] The vehicle controller is used to: after the plug of the AC charging pile is connected to the charging socket of the electric vehicle, receive the charging request signal sent by the on-board charger, and the charging request signal is used to indicate that the connection between the on-board charger and the AC charging pile is complete; after receiving the charging request signal, control the on-board charger to receive the AC power output by the AC charging pile and convert the AC power into DC power to charge the power battery; in the process of the on-board charger charging the power battery, control the size of the DC power output by the on-board charger according to the impedance of the transmission line, wherein the greater the impedance of the transmission line, the smaller the DC power output by the on-board charger is controlled.

[0036] For the supplementary and technical effects of the solutions provided in the second and third aspects above, please refer to the corresponding description of the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram of an application scenario is shown;

[0038] Figure 2 A schematic diagram of an electric vehicle provided in an embodiment of the present application is shown;

[0039] Figure 3 A schematic structural diagram of a vehicle charger provided in an embodiment of the present application is shown;

[0040] Figure 4 A schematic diagram of a circuit structure of a power conversion circuit provided in an embodiment of the present application is shown;

[0041] Figure 5 A schematic structural diagram of another on-board charger provided in an embodiment of the present application is shown;

[0042] Figure 6 A schematic diagram of an AC charging pile and an electric vehicle provided in an embodiment of the present application is shown;

[0043] Figure 7 A schematic diagram showing the relationship between the impedance of a transmission line and the comprehensive charging efficiency provided by an embodiment of the present application is shown;

[0044] Figure 8 A schematic diagram showing the relationship between direct current and the impedance of a transmission line provided in an embodiment of the present application is shown;

[0045] Figure 9 A schematic diagram showing the relationship between direct current and comprehensive charging efficiency provided in an embodiment of the present application is shown;

[0046] Figure 10 A schematic diagram showing the relationship between direct current and preset charging time provided in an embodiment of the present application is shown;

[0047] Figure 11A timing diagram of direct current provided by an embodiment of the present application is shown;

[0048] Figure 12 A schematic diagram showing the relationship between another direct current and comprehensive charging efficiency provided in an embodiment of the present application is shown;

[0049] Figure 13 A schematic diagram showing another relationship between direct current and preset charging time provided in an embodiment of the present application is shown;

[0050] Figure 14 A schematic diagram of a vehicle controller provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0052] In the embodiments of this application, prefixes such as "first" and "second" are used only to distinguish different description objects and have no limiting effect on the position, order, priority, quantity, or content of the described objects. The use of prefixes such as ordinal numbers in the embodiments of this application to distinguish description objects does not constitute a limitation on the described objects. For a statement of the described objects, please refer to the description in the context of the claims or embodiments, and the use of such prefixes should not constitute an unnecessary limitation.

[0053] With the continuous development of the electric vehicle industry, electric vehicles are usually charged through on-board chargers (OBC) and charging piles. Some charging piles require transmission lines of tens or even hundreds of meters to connect to the distribution box. Figure 1 When charging electric vehicles on a daily basis, there is some power loss in the transmission line between the distribution box and the charging pile, which makes the overall charging efficiency of the on-board charger (OBC) low. Since the electric meter is usually installed in the distribution box, the power loss of the transmission line needs to be borne by the user.

[0054] In view of this, embodiments of the present application provide a control method, a vehicle controller, and an electric vehicle for improving the charging efficiency of an on-board charger, which adjusts the magnitude of the DC power output by the on-board charger according to the impedance of the transmission line to improve the charging efficiency of the on-board charger.

[0055] Among them, the direct current output by the on-board charger is the charging current for charging the power battery.

[0056] See Figure 2 , Figure 2 A schematic diagram of an electric vehicle is shown. Figure 2 As shown, the electric vehicle 100 includes at least an on-board charger 110 , a power battery 120 and a vehicle controller 130 .

[0057] When the onboard charger 110 is used to charge the power battery 120 , the onboard charger 110 is connected to the AC charging pile 140 , and the onboard charger 110 converts the AC power from the AC charging pile 140 into DC power to charge the power battery 120 .

[0058] The maximum current value of the DC power used to charge the power battery 120 is determined by the vehicle controller 130 and can be the minimum value among the maximum current of the power battery 120 , the maximum current of the onboard charger 110 , and the maximum current of the AC charging pile 140 .

[0059] The on-board charger 110 is also used to supply power to an external load. When the on-board charger 110 supplies power to an external load, the on-board charger 110 is used to connect to an external load 150 outside the vehicle. The on-board charger 110 is used to convert direct current from the power battery 120 into alternating current to supply power to the external load 150 .

[0060] See Figure 3 , Figure 3 The schematic diagram of the structure of an on-board charger is shown. The on-board charger 110 includes a control circuit 111, a power conversion circuit 112, and an insulating housing 113. The control circuit 111 and the power conversion circuit 112 are housed in the insulating housing 113. The control circuit 111 is used to control the operation of the power conversion circuit 112. The power conversion circuit 112 includes a power factor correction circuit 1121 and a bidirectional DC conversion circuit 1122. The insulating housing 113 includes a power battery interface 1131 and an external power supply interface 1132.

[0061] When the onboard charger 110 is used to charge the power battery 120, Figure 3 As shown in (a) of FIG. 1 , the external power supply interface 1132 is used to connect to the charging plug of the AC charging station 140, and the power battery interface 1131 is used to connect to the power battery 120 of the electric vehicle 100. The power factor correction circuit 1121 is now operating in rectification mode, converting the AC power from the AC charging station 140 into DC power. The bidirectional DC conversion circuit 1122 steps down the DC power output by the power factor correction circuit 1121 and outputs it to charge the power battery 120.

[0062] When the onboard charger 110 is used to supply power to the outside, Figure 3As shown in (b), the external power supply interface 1132 is used to connect the external load 150, the power battery interface 1131 is used to connect the power battery 120, the bidirectional DC conversion circuit 1122 is used to adjust the voltage of the DC power from the power battery 120, and the power factor correction circuit 1121 operates in the inverter mode at this time. The power factor correction circuit 1121 is used to convert the DC power output by the DC conversion circuit into AC power to power the external load 150.

[0063] See Figure 4 , Figure 4 The power conversion circuit 112 includes a power factor correction circuit 1121 and a bidirectional DC conversion circuit 1122 .

[0064] like Figure 4 As shown in (a) of FIG. 1 , the bidirectional DC conversion circuit 1122 includes a primary power circuit 1123 , a transformer 1124 and a secondary power circuit 1125 .

[0065] When the on-board charger 110 is used to charge the power battery 120 , the primary power circuit 1123 of the bidirectional DC conversion circuit 1122 transfers electrical energy to the secondary power circuit 1125 through the transformer 1124 .

[0066] When the on-board charger 110 is used to supply power externally, the secondary power circuit 1125 of the bidirectional DC conversion circuit 1122 transfers electrical energy to the primary power circuit 1123 through the transformer 1124 .

[0067] like Figure 4 As shown in (b), Figure 4 (b) in FIG. 1 shows a schematic diagram of a circuit structure of a power factor correction circuit. The working modes of the power factor correction circuit 1121 include a rectification mode and an inverter mode.

[0068] When the power factor correction circuit 1121 operates in rectification mode, it converts AC power into DC power. The bidirectional DC conversion circuit 1122 steps down the DC power output from the power factor correction circuit 1121 and outputs it to charge the power battery 120.

[0069] When the power factor correction circuit 1121 operates in the inverter mode, the power factor correction circuit 1121 is used to convert AC power into DC power. The power factor correction circuit 1121 is used to receive DC power from the bidirectional DC conversion circuit 1122 and convert it into AC power to power the external load 150.

[0070] See Figure 5 , Figure 5 Shows a structural diagram of another on-board charger. Figure 5In the vehicle, the onboard charger 110 is Figure 3 In addition to the structure shown in (a), the DC conversion circuit 114 is further included, and the insulating housing 113 further includes an internal power supply interface 1133. The DC conversion circuit 114 can be accommodated inside the insulating housing 113 or outside the insulating housing.

[0071] like Figure 5 As shown in (a) of FIG. 1 , the internal power supply interface 1133 is used to connect to a low-voltage load 160. The DC converter circuit 114 is used to step down the DC power output by the power battery 120 to power the low-voltage load 160 on the electric vehicle 100. The low-voltage load 160 includes a low-voltage battery and other low-voltage electrical appliances, such as windshield wipers and an air conditioning compressor.

[0072] In one embodiment, the DC conversion circuit 114 may also receive DC power from the bidirectional DC conversion circuit 1122 and step down the DC power to supply power to the low-voltage load 160 on the electric vehicle 100 .

[0073] like Figure 5 As shown in (b), Figure 5 (b) in FIG. 1 shows a schematic diagram of the circuit structure of the on-board charger 110. Figure 4 The circuit structure diagram of the power conversion circuit 112 shown in FIG. 1 is newly added with a DC conversion circuit 114 .

[0074] in, Figure 5 The on-board charger shown is a two-in-one design of on-board charger and on-board DCDC converter, that is, Figure 5 The on-board charger 110 shown integrates Figure 3 The on-board charger and on-board DCDC converter are shown.

[0075] The architecture of the embodiment of the present application is described above. The control method for improving the charging efficiency of the on-board charger provided by the present application is described below in conjunction with specific embodiments.

[0076] A control method for improving the charging efficiency of an on-board charger provided in an embodiment of the present application is used to adjust the magnitude of the direct current output by the on-board charger according to the impedance of a transmission line to improve the charging efficiency of the on-board charger.

[0077] Among them, the comprehensive charging efficiency of the on-board charger P battery Refers to the charging power of the power battery, P total Refers to the output power at the distribution box.

[0078] P battery =U obc In obc , U obcRefers to the charging voltage of the on-board charger, I refers to the DC power of the on-board charger, η obc Refers to the charging efficiency of the on-board charger, which is usually around 95%. The lower the input voltage, η obc The lower; P total =U obc I+I 2 R, R is the impedance of the transmission line that inputs current to the on-board charger.

[0079] The control method for improving the charging efficiency of a vehicle charger provided in an embodiment of the present application includes the following steps.

[0080] After the plug of the AC charging pile is connected to the charging socket of the electric vehicle, a charging request signal sent by the on-board charger is received, where the charging request signal is used to indicate that the connection between the on-board charger and the AC charging pile is complete.

[0081] After the on-board charger and the AC charging pile are connected, the electric vehicle is in a non-driving state.

[0082] See also Figure 6 , Figure 6 A schematic diagram of an AC charging pile and an electric vehicle is shown.

[0083] After the AC charging pile plug is connected to the charging socket of the electric vehicle, the AC charging pile is started to start charging. Figure 6 As shown in the figure, the AC charging station sends a pulse width modulation (PWM) signal to the electric vehicle. After detecting the PWM signal and performing a self-test, the onboard charger sends a charging request signal to the vehicle controller and supplies power to the vehicle controller. The vehicle controller can be considered an external load. The PWM signal carries the maximum charging current of the AC charging station.

[0084] After receiving the charging request signal, the on-board charger is controlled to receive the AC power output by the AC charging pile and convert the AC power into DC power to charge the power battery.

[0085] The specific process of the on-board charger receiving the AC power output by the AC charging pile and converting the AC power into DC power to charge the power battery can be found in Figures 3 to 5 And the related descriptions will not be repeated here.

[0086] When the on-board charger is charging the power battery, the DC power output by the on-board charger is controlled according to the impedance of the transmission line. The greater the impedance of the transmission line, the smaller the DC power output by the on-board charger.

[0087] Analyze the comprehensive charging efficiency η of the on-board charger. U refers to the voltage at the AC charging station, and R is the impedance of the transmission line.

[0088] According to the calculation formula (1), we know that: U and η obc It is usually a certain value. The comprehensive charging efficiency η is mainly determined by I and R. When I is constant, the larger R is, the more power is consumed on the transmission line, and the smaller the comprehensive charging efficiency η is.

[0089] For easier understanding, see Figure 7 , Figure 7 A schematic diagram showing the relationship between the impedance of a transmission line and the comprehensive charging efficiency is shown.

[0090] like Figure 7 As shown in Figure 2, the comprehensive charging efficiency decreases as the impedance of the transmission line increases.

[0091] In this case, the greater the impedance of the transmission line, the smaller the DC power output of the on-board charger can be controlled, thereby reducing the power consumed on the transmission line during the process of the on-board charger charging the power battery, improving the overall charging efficiency of the on-board charger, and saving power consumption and electricity costs.

[0092] For easier understanding, see Figure 8 , Figure 8 A schematic diagram showing the relationship between direct current and the impedance of a transmission line is shown.

[0093] like Figure 8 As shown in Figure 3, the DC power output by the on-board charger decreases as the impedance of the transmission line increases.

[0094] In one embodiment, the correspondence between the impedance of the transmission line and the magnitude of the DC power output by the on-board charger can be calibrated in advance based on the comprehensive charging efficiency.

[0095] The specific calibration method may include: for an impedance, obtaining the comprehensive charging efficiency of charging the power battery with multiple DC currents of different sizes under the impedance; obtaining the DC current corresponding to the maximum comprehensive charging efficiency among the multiple comprehensive charging efficiencies or the comprehensive charging efficiency greater than a specified value as the DC current corresponding to the impedance, thereby obtaining the DC current corresponding to each of the multiple impedances, and obtaining the corresponding relationship between the impedance of the transmission line and the size of the DC current output by the on-board charger.

[0096] In this embodiment, the connection between the on-board charger and the AC charging pile is detected by automatically detecting a charging request signal. After confirming that the connection between the on-board charger and the AC charging pile is complete, the on-board charger is controlled to convert the AC power output from the AC charging pile into DC power to charge the power battery, thereby preventing damage to the electric vehicle's hardware and software due to poor contact, excessive output voltage from the AC charging pile, etc. During the process of charging the power battery, the amount of DC power output by the on-board charger is controlled according to the impedance of the transmission line. This allows for flexible control of the amount of DC power output by the on-board charger under different impedance levels. Furthermore, the greater the impedance of the transmission line, the smaller the DC power output by the on-board charger. This reduces the amount of power consumed in the transmission line during the process of charging the power battery, improves the overall charging efficiency of the on-board charger, and saves power consumption and electricity costs.

[0097] In one embodiment, the control method specifically includes: when the impedance of the transmission line is a first impedance, controlling the DC power output by the on-board charger to be a first DC power; when the impedance of the transmission line is a second impedance greater than the first impedance, controlling the DC power output by the on-board charger to be a second DC power less than the first DC power.

[0098] In the embodiment of the present application, there is no limitation on the specific values of the first impedance, the second impedance, the first direct current, and the second direct current, wherein the first impedance is smaller than the second impedance, and the first direct current is greater than the second direct current.

[0099] In this embodiment, when the on-board charger is charging the power battery, the on-board charger is controlled to output a larger first DC power when the impedance of the transmission line is a smaller first impedance, and is controlled to output a smaller second DC power when the impedance of the transmission line is a larger second impedance. The DC power output by the on-board charger is flexibly controlled under different impedance sizes, thereby reducing the amount of power consumed on the transmission line during the process of charging the power battery by the on-board charger, improving the overall charging efficiency of the on-board charger, and saving power consumption and electricity costs.

[0100] In some cases, the lower the DC power output of the onboard charger, the longer it takes to fully charge the power battery. If the full charge time is too long and the user expects a high charging power to quickly charge the power battery, the DC power output of the onboard charger may not meet the user's needs, resulting in a poor user experience.

[0101] Thus, in one embodiment, the control method further includes: during the process of the on-board charger charging the power battery, controlling the magnitude of the DC power output by the on-board charger according to a preset charging time set by the user.

[0102] Among them, the preset charging time can indicate the user's charging needs. The longer the preset charging time, the weaker the user's demand for high charging power and fast full charging; the shorter the preset charging time, the stronger the user's demand for high charging power and fast full charging.

[0103] The preset charging time can be the charging time set by the user through the vehicle display screen, or the charging time set by the user through a terminal device such as a mobile phone or computer that is connected to the electric vehicle.

[0104] The preset charging time may also be the charging time corresponding to an operation triggered by the user, for example, the charging time corresponding to a charging mode selected by the user, or the charging time corresponding to a charging time interval selected by the user.

[0105] In this embodiment, the preset charging time is set by the user, and the preset charging time can reflect the user's charging needs. By controlling the amount of DC power output by the on-board charger according to the preset charging time, the amount of DC power output by the on-board charger can be flexibly controlled under different preset charging time values, so as to fully charge the power battery within the preset charging time, thereby meeting the user's charging needs and improving the user experience.

[0106] In an embodiment of the present application, when the on-board charger is charging the power battery, the amount of DC power output by the on-board charger is controlled according to the impedance of the transmission line and the preset charging time, so as to fully charge the power battery within the preset charging time to meet the user's charging needs while reducing the power consumption on the transmission line.

[0107] Among them, the correspondence between the impedance of the transmission line, the preset charging time and the amount of DC power output by the on-board charger can be calibrated in advance based on the comprehensive charging efficiency.

[0108] In one embodiment, the control method specifically includes: the longer the preset charging time is, the smaller the DC power output by the on-board charger is controlled.

[0109] The longer the preset charging time is, the weaker the user's demand for high charging power and fast full charging is, and the smaller the DC power output of the on-board charger can be to fully charge the power battery within the preset charging time.

[0110] According to the calculation formula (1), when R is constant, the smaller I is, the less power is consumed on the transmission line, and the greater the comprehensive charging efficiency η is.

[0111] For easier understanding, see Figure 9 , Figure 9 A schematic diagram showing the relationship between direct current and comprehensive charging efficiency is shown.

[0112] like Figure 9As shown in Figure 2, the comprehensive charging efficiency increases with the decrease of DC current.

[0113] When the preset charging time is longer, that is, the user's demand for high charging power and fast full charging is weaker, the DC power output of the on-board charger can be controlled to be smaller, so as to reduce the power consumed on the transmission line during the process of the on-board charger charging the power battery, improve the overall charging efficiency of the on-board charger, and save power consumption and electricity costs.

[0114] For easier understanding, see Figure 10 , Figure 10 A schematic diagram showing the relationship between direct current and preset charging time is shown.

[0115] like Figure 10 As shown in FIG, the DC power output by the on-board charger decreases as the preset charging time increases.

[0116] In one embodiment, the correspondence between the preset charging time and the amount of direct current output by the on-board charger can be calibrated in advance.

[0117] The specific calibration method may include: for a preset charging time, obtaining the DC power that just fully charges the power battery within the preset charging time; obtaining the DC power corresponding to multiple preset charging times, and then obtaining the corresponding relationship between the preset charging time and the size of the DC power output by the on-board charger.

[0118] It can be understood that the DC power that fully charges the power battery within a preset charging time is the minimum DC power corresponding to the preset charging time, and at this time the comprehensive charging efficiency of the on-board charger is the highest.

[0119] In one embodiment, the power battery is charged with DC power that is greater than the minimum DC power and has a difference with the minimum DC power by a preset difference, thereby reducing the power consumed on the transmission line during the process of the on-board charger charging the power battery.

[0120] In this embodiment, when the on-board charger is charging the power battery, the longer the preset charging time is, that is, the weaker the user's demand for high charging power and fast full charging, the DC power output of the on-board charger is controlled to be smaller, so that the power battery can be fully charged within the preset charging time while reducing the power consumption on the transmission line, thereby meeting the user's charging needs while improving the overall charging efficiency of the on-board charger.

[0121] In one embodiment, the control method further includes: at a first moment t1, the preset charging time is a first preset time, and the DC power output by the on-board charger is controlled to be a third DC power; at a second moment t2 after the first moment t1, the preset charging time is a second preset time that is greater than the first preset time, and during the process of the on-board charger being used to charge the power battery, the DC power output by the on-board charger is controlled to be reduced to a fourth DC power that is less than the third DC power.

[0122] In the embodiment of the present application, there is no restriction on the specific values of the first preset time, the second preset time, the third direct current and the fourth direct current, wherein the first preset time is less than the second preset time, and the third direct current is greater than the fourth direct current.

[0123] For easier understanding, see Figure 11 , Figure 11 A timing diagram of direct current is shown.

[0124] At the first moment t1, the preset charging time is the first preset time, and the DC power output by the on-board charger is the third DC power I1; at the second moment t2 after the first moment t1, the preset charging time is changed to the second preset time, and the DC power output by the on-board charger is reduced to the fourth DC power I2 which is less than the third DC power I1.

[0125] In this embodiment, during the process of the on-board charger charging the power battery, after the preset charging time is changed from the first preset time to a larger second preset time, the DC power output by the on-board charger is controlled to be reduced to a fourth DC power that is smaller than the third DC power, so that the DC power output by the on-board charger is more in line with the user's weaker demand for high charging power and fast full charging after the change. In the scenario involving the change of the preset charging time, the power battery can be fully charged within the changed preset charging time while the overall charging efficiency of the on-board charger is improved.

[0126] However, when the on-board charger is charging the power battery, low-voltage loads (such as air conditioners, multimedia players, etc.) are generally running in the electric vehicle, and the on-board charger or power battery also needs to supply power to these low-voltage loads. In this case, the comprehensive charging efficiency η of the on-board charger also needs to consider the output power P of the DCDC converter or DC conversion circuit. DCDC , comprehensive charging efficiency

[0127] When I is too small, it is not possible to supply power to the low-voltage load while charging the power battery with high comprehensive charging efficiency. At this time, the comprehensive charging efficiency of the on-board charger will not increase but will decrease.

[0128] For easier understanding, see Figure 12 , Figure 12 Another schematic diagram showing the relationship between DC power and comprehensive charging efficiency is shown.

[0129] like Figure 12 As shown in FIG, before the DC current decreases to a certain value, the comprehensive charging efficiency increases as the DC current decreases. After the DC current decreases to a certain value, the comprehensive charging efficiency decreases as the DC current decreases.

[0130] In one embodiment, the control method specifically includes: when a preset charging time is greater than or equal to a preset value, controlling the DC power output by the on-board charger not to decrease as the preset charging time increases.

[0131] In the embodiments of the present application, there is no limitation on the specific numerical value of the preset value.

[0132] Among them, the preset value refers to the time it takes for the on-board charger to output direct current with high comprehensive charging efficiency to charge the power battery just to fully charge the power battery when powering the low-voltage load in the electric vehicle. When the preset charging time is the preset value, the direct current output by the on-board charger is controlled to be the minimum direct current allowed for fully charging the power battery when powering the low-voltage load in the electric vehicle.

[0133] When the preset charging time is longer than the preset value, reducing the DC power will make it impossible for the DC power to supply power to the low-voltage load while charging the power battery with high comprehensive charging efficiency. The DC power may even be unable to supply power to the low-voltage load, thereby reducing the comprehensive charging efficiency of the on-board charger.

[0134] In one embodiment, the high comprehensive charging efficiency of the on-board charger can be pre-calibrated. For example, if the comprehensive charging efficiency of the on-board charger is greater than a specified percentage (e.g., 88%, 85%, 83%, etc.), the comprehensive charging efficiency is considered high. Electric vehicles of the same model or configuration will have the same high comprehensive charging efficiency. Furthermore, the high comprehensive charging efficiency can be adjusted over the life of the on-board charger.

[0135] When the preset charging time is less than the preset value, the DC power output by the on-board charger is controlled to decrease as the preset charging time increases, and the comprehensive charging efficiency of the on-board charger increases as the DC power decreases.

[0136] For easier understanding, see Figure 13 , Figure 13 A schematic diagram showing another relationship between direct current and preset charging time is shown.

[0137] like Figure 13 As shown, when the preset charging time is less than the preset value, the DC power output by the on-board charger decreases as the preset charging time increases, and the comprehensive charging efficiency of the on-board charger increases as the DC power decreases.

[0138] When the preset charging time is greater than or equal to the preset value, the DC power output by the on-board charger does not decrease as the preset charging time increases.

[0139] In this embodiment, during the process of the on-board charger charging the power battery, by setting a preset value, when the preset charging time is greater than or equal to the preset value, the DC power output by the on-board charger is controlled not to decrease as the preset charging time increases. This comprehensively considers the scenario where the on-board charger simultaneously supplies power to the low-voltage load in the electric vehicle during the process of charging the power battery, and limits the DC power output of the on-board charger to not change with the change of the preset charging time. This avoids the situation where the on-board charger cannot meet the requirements of charging the power battery with high comprehensive charging efficiency while supplying power to the low-voltage load due to too little DC power, thereby ensuring the high comprehensive charging efficiency of the on-board charger.

[0140] In one embodiment, the control method specifically includes: during the process of the on-board charger charging the power battery, controlling the direct current output by the on-board charger to be greater than or equal to a preset current.

[0141] Among them, the preset current is the minimum DC current allowed to fully charge the power battery with high comprehensive charging efficiency when powering the low-voltage load in the electric vehicle. It can be considered to be the DC current corresponding to the preset value during the preset charging time.

[0142] like Figure 13 As shown, when the preset charging time is greater than or equal to the preset value, the charging current output by the on-board charger remains unchanged, which is the preset current I3, and the comprehensive charging efficiency of the on-board charger remains unchanged and is the highest.

[0143] In this embodiment, during the process of the on-board charger charging the power battery, comprehensive consideration is given to the scenario of simultaneously powering the low-voltage loads in the electric vehicle while the on-board charger is charging the power battery. By controlling the DC power output by the on-board charger to be greater than or equal to the preset current, the charging current output by the on-board charger is limited to not be too small, thereby avoiding the situation where the on-board charger cannot meet the requirements of charging the power battery with high comprehensive charging efficiency while powering the low-voltage loads due to the charging current being too small, thereby ensuring the high comprehensive charging efficiency of the on-board charger.

[0144] In one embodiment, the control method specifically includes: when the on-board charger is charging the power battery and supplying power to the load of the electric vehicle at the same time, controlling the on-board charger to output DC power greater than the power supplying power to the load of the electric vehicle.

[0145] The load here refers to the load inside the electric vehicle, that is, the low-voltage load mentioned above. The higher the power of the load, the more electricity the load consumes, and the lower the overall charging efficiency.

[0146] If the DC power output by the on-board charger is greater than the power supplied to the load of the electric vehicle, it means that the on-board charger is effectively charging the power battery; if the DC power output by the on-board charger is less than or equal to the power supplied to the load of the electric vehicle, it means that the DC power output by the on-board charger is all used to supply power to the load of the electric vehicle, and the power battery is not effectively charged, or even consumed in reverse.

[0147] In this embodiment, while the on-board charger is charging the power battery and supplying power to the load of the electric vehicle at the same time, by controlling the power of the DC power output by the on-board charger to be greater than the power supplying power to the load of the electric vehicle, the on-board charger can effectively charge the power battery while supplying power to the load.

[0148] In one embodiment, the predetermined current increases as the power of the load of the electric vehicle increases.

[0149] The greater the power of the electric vehicle's load, the larger the branch of the direct current output by the on-board charger used to power the load.

[0150] From the foregoing, it can be seen that the preset current is the minimum DC current allowed to fully charge the power battery with a high overall charging efficiency when powering the low-voltage load in the electric vehicle. When the load increases, the preset current increases with the increase in the power of the electric vehicle's load, ensuring that the on-board charger still charges the power battery with a high overall charging efficiency.

[0151] The following describes in detail the changes in the DC power output by the on-board charger during the process of the on-board charger being used to charge the power battery.

[0152] In one embodiment, the control method specifically includes: when the on-board charger is charging the power battery, the longer the length of the transmission line is, the smaller the DC power output by the on-board charger is controlled.

[0153] Among them, the length of the transmission line determines the impedance of the transmission line.

[0154] The length of the transmission line can be the length of the transmission line from the AC charging pile to the distribution box, or it can be the sum of the length of the transmission line from the on-board charger to the AC charging pile and the length of the transmission line from the AC charging pile to the distribution box.

[0155] From the calculation formula (1), we can see that the larger R is, the greater the power loss on the transmission line is, and the lower the comprehensive charging efficiency of the on-board charger is.

[0156] According to tests, when the length of the transmission line is 100 meters, that is, the impedance is about 1Ω, when the DC current is reduced from 32A to 12A, the total amount and charging efficiency are improved by about 9%. Charging 30 degrees can save 4.7 degrees of electricity. Based on an annual charging mileage of 20,000 kilometers and 15 degrees of electricity per 100 kilometers, 3,000 degrees of electricity consumption can save 470 degrees of electricity, which is equivalent to an electricity bill of about 300 yuan.

[0157] In this embodiment, when the on-board charger is charging the power battery, the longer the transmission line is, the smaller the DC power output by the on-board charger is controlled, thereby reducing the power loss on the transmission line and improving the overall charging efficiency of the on-board charger.

[0158] In one embodiment, the control method specifically includes: when the on-board charger is charging the power battery, the higher the ambient temperature is, the smaller the DC power output by the on-board charger is controlled.

[0159] It is understandable that the impedance of the transmission line increases with the increase of the ambient temperature. For example, the impedance of a 100-meter copper wire is 0.287Ω at 20°C and 0.2926Ω at 26°C.

[0160] The higher the ambient temperature, the greater the impedance of the transmission line.

[0161] From the calculation formula (1), we can see that the larger R is, the greater the power loss on the transmission line is, and the lower the comprehensive charging efficiency of the on-board charger is.

[0162] In this embodiment, when the on-board charger is charging the power battery, the higher the ambient temperature is, the smaller the DC power output by the on-board charger is controlled to be, thereby reducing the power loss on the transmission line and improving the overall charging efficiency of the on-board charger.

[0163] In one embodiment, the control method specifically includes: when the on-board charger is charging the power battery, the lower the remaining power of the power battery is, the smaller the DC power output by the on-board charger is controlled.

[0164] The more remaining power in the power battery, the less power the power battery needs to be charged. When the preset charging time is known, the DC power output of the on-board charger for a fully charged power battery can be smaller, and the overall charging efficiency of the on-board charger is greater.

[0165] During the charging process of the power battery, if the remaining power of the power battery is low, it is very likely that the power battery will not be able to maintain the operation of the low-voltage load in the electric vehicle or the external load. The power demand of this scenario can be met by outputting a larger amount of DC power.

[0166] In this embodiment, when the on-board charger is charging the power battery, the lower the remaining power of the power battery is, the smaller the DC power output of the on-board charger is controlled, thereby meeting the power demand in the low remaining power scenario while improving the overall charging efficiency of the on-board charger.

[0167] In one embodiment, in response to receiving a trigger instruction, the on-board charger is controlled to output direct current according to information indicated by the trigger instruction.

[0168] The trigger instruction may be a command triggered by a user selecting a charging mode on an onboard display screen or a terminal device connected to the electric vehicle. The charging modes include at least a high efficiency mode and a high power mode.

[0169] When the trigger instruction indicates that the charging mode is the high-efficiency mode, the DC power output by the on-board charger is controlled to be a preset current so that the comprehensive charging efficiency of the on-board charger is the highest.

[0170] In this embodiment, when the on-board charger is used to charge the power battery, the on-board charger is controlled to output direct current in response to receiving a trigger instruction and according to the information indicated by the trigger instruction, thereby realizing automatic detection of instructions and control of output current, thereby improving the control speed and response speed of the on-board charger.

[0171] An embodiment of the present application provides a vehicle controller, which is used to: after the plug of the AC charging pile is connected to the charging socket of the electric vehicle, receive a charging request signal sent by the on-board charger, and the charging request signal is used to indicate that the connection between the on-board charger and the AC charging pile is complete; after receiving the charging request signal, control the on-board charger to receive the AC power output by the AC charging pile and convert the AC power into DC power to charge the power battery; during the process of the on-board charger charging the power battery, control the size of the DC power output by the on-board charger according to the impedance of the transmission line, wherein the greater the impedance of the transmission line, the smaller the DC power output by the on-board charger is controlled.

[0172] For easier understanding, see Figure 14 , Figure 14 A schematic diagram of a vehicle controller is shown.

[0173] like Figure 14 As shown, after the plug of the AC charging pile is connected to the charging socket of the electric vehicle, the on-board charger sends a charging request signal to the vehicle controller. After receiving the charging request signal, the vehicle controller sends a control signal to the on-board charger according to the impedance of the transmission line to control the amount of DC power output by the on-board charger.

[0174] In one embodiment, the vehicle controller may be a vehicle controller of an electric vehicle, or may be another vehicle controller to achieve redundancy backup.

[0175] In another embodiment of the present application, an electric vehicle is also provided, which includes an on-board charger, a vehicle controller and a power battery. The on-board charger is used to receive AC power output from an AC charging pile through a transmission line and convert the AC power into DC power to charge the power battery.

[0176] The vehicle controller is used to: after the plug of the AC charging pile is connected to the charging socket of the electric vehicle, receive the charging request signal sent by the on-board charger, and the charging request signal is used to indicate that the connection between the on-board charger and the AC charging pile is complete; after receiving the charging request signal, control the on-board charger to receive the AC power output by the AC charging pile and convert the AC power into DC power to charge the power battery; in the process of the on-board charger charging the power battery, control the size of the DC power output by the on-board charger according to the impedance of the transmission line, wherein the greater the impedance of the transmission line, the smaller the DC power output by the on-board charger is controlled.

[0177] It can be understood that all relevant contents involved in the above method embodiments can be referred to the embodiments of the vehicle controller and the embodiments of the electric vehicle, and the embodiments of the present application will not be repeated here.

[0178] Finally, it should be noted that the above are only specific embodiments of this application, but the scope of protection of this application is not limited to them. Any changes or substitutions within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A control method for improving the charging efficiency of a vehicle charger, characterized in that: The on-board charger is used to receive AC power output from an AC charging pile through a transmission line and convert the AC power into DC power to charge the power battery. The control method is used to adjust the magnitude of the DC power output by the on-board charger according to the impedance of the transmission line to improve the charging efficiency of the on-board charger. The control method includes: After the plug of the AC charging pile is connected to the charging socket of the electric vehicle, a charging request signal is received from the on-board charger, where the charging request signal is used to indicate that the connection between the on-board charger and the AC charging pile is completed; After receiving the charging request signal, controlling the on-board charger to receive the AC power output by the AC charging pile and converting the AC power into DC power to charge the power battery; During the process of the on-board charger charging the power battery, the magnitude of the direct current output by the on-board charger is controlled according to the impedance of the transmission line, wherein the greater the impedance of the transmission line, the smaller the direct current output by the on-board charger is controlled.

2. The control method according to claim 1, characterized in that: The control method specifically includes: When the impedance of the transmission line is a first impedance, controlling the direct current output by the on-board charger to be a first direct current; When the impedance of the transmission line is a second impedance greater than the first impedance, the direct current output by the on-board charger is controlled to be a second direct current less than the first direct current.

3. The control method according to claim 1, wherein: The control method further includes: During the process of the on-board charger charging the power battery, the magnitude of the direct current output by the on-board charger is controlled according to a preset charging time set by a user.

4. The control method according to claim 3, characterized in that: The control method specifically includes: The longer the preset charging time is, the smaller the DC power output by the on-board charger is.

5. The control method according to claim 3, characterized in that: The control method specifically includes: The preset charging time is greater than or equal to a preset value, and the DC power output by the on-board charger is controlled not to decrease as the preset charging time increases.

6. The control method according to any one of claims 1 to 5, characterized in that: The control method specifically includes: During the process of the on-board charger charging the power battery, the direct current output by the on-board charger is controlled to be greater than or equal to a preset current.

7. The control method according to any one of claims 1 to 5, characterized in that: The control method specifically includes: In the process of the on-board charger charging the power battery and supplying power to the load of the electric vehicle at the same time, the on-board charger is controlled to output the DC power greater than the power supplying power to the load of the electric vehicle.

8. The control method according to any one of claims 1 to 5, characterized in that: The control method specifically includes: During the process of the on-board charger charging the power battery, the longer the length of the transmission line is, the smaller the DC power output by the on-board charger is controlled.

9. The control method according to any one of claims 1 to 5, characterized in that: The control method specifically includes: During the process of the on-board charger charging the power battery, the higher the ambient temperature is, the smaller the DC power output by the on-board charger is controlled.

10. The control method according to any one of claims 1 to 5, characterized in that: The control method specifically includes: During the process of the on-board charger charging the power battery, the lower the remaining power of the power battery is, the smaller the DC power output by the on-board charger is controlled.

11. A vehicle controller, characterized in that: The vehicle controller is used to: After the plug of the AC charging pile is connected to the charging socket of the electric vehicle, a charging request signal is received from the on-board charger, where the charging request signal indicates that the connection between the on-board charger and the AC charging pile is complete; After receiving the charging request signal, controlling the on-board charger to receive the AC power output by the AC charging pile and converting the AC power into DC power to charge the power battery; During the process of the on-board charger charging the power battery, the magnitude of the direct current output by the on-board charger is controlled according to the impedance of the transmission line, wherein the greater the impedance of the transmission line, the smaller the direct current output by the on-board charger is controlled.

12. An electric vehicle, characterized in that: The electric vehicle includes an on-board charger, a vehicle controller, and a power battery. The on-board charger is used to receive AC power output from an AC charging pile through a transmission line and convert the AC power into DC power to charge the power battery. The vehicle controller is used to: After the plug of the AC charging pile is connected to the charging socket of the electric vehicle, a charging request signal is received from the on-board charger, where the charging request signal is used to indicate that the connection between the on-board charger and the AC charging pile is completed; After receiving the charging request signal, controlling the on-board charger to receive the AC power output by the AC charging pile and converting the AC power into DC power to charge the power battery; During the process of the on-board charger charging the power battery, the magnitude of the direct current output by the on-board charger is controlled according to the impedance of the transmission line, wherein the greater the impedance of the transmission line, the smaller the direct current output by the on-board charger is controlled.

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