System and method for charging a battery of a vehicle

Abstract

The present disclosure relates to a charging system and a charging method for charging a main battery of a vehicle. A DC-DC converter of an on-board computer (OBC) can be used to charge the main battery using the voltage of replaceable batteries without installing additional converters for the replaceable batteries by connecting the replaceable batteries to the input terminals of the plurality of DC-DC converters of the OBC charging the main battery, thereby increasing the driving distance of the vehicle and improving the efficiency of the motor and the inverter.

Description

Technical Field

[0001] This disclosure relates to a system and method for charging the main battery of a vehicle, and more specifically, to a system and method for charging the main battery of a vehicle that can use not only external AC power but also a replaceable battery built into the vehicle to charge the main battery of the vehicle. Background Technology

[0002] Environmentally friendly vehicles (e.g., electric vehicles or plug-in hybrid electric vehicles) that use batteries as the energy source for the drive motor in the vehicle have an onboard charger for converting external AC power to DC power and using DC power to charge the battery.

[0003] On the other hand, the price of high-voltage batteries affects the cost competitiveness of environmentally friendly vehicles. To minimize the price of these batteries, technological development has focused on reducing battery capacity and voltage. However, reducing the capacity of these high-voltage batteries results in reduced vehicle range and decreased motor / inverter output.

[0004] To address the aforementioned issues, a scheme is proposed that involves installing one or more replaceable batteries within a vehicle and using one or more replaceable batteries to charge the main battery.

[0005] The main battery and the replaceable battery can have the same maximum voltage, but their voltages vary within a variable range depending on their state of charge (SOC). Therefore, if they are connected with a simple short-circuit connection, there is a risk of fire and component burnout due to voltage differences. Consequently, to charge the main battery using the replaceable battery, an additional DC-DC converter is typically required for each replaceable battery, which increases battery cost and size and reduces efficiency. Therefore, a converter control device is needed to improve their performance.

[0006] The foregoing background information is intended only to help understand the context of this disclosure and is not intended to imply that this disclosure falls within the scope of prior art known to those skilled in the art. Summary of the Invention

[0007] One aspect of this disclosure is to provide a system and method for charging a vehicle battery, which can use the DC-DC converter of an on-board computer (OBC) to charge the main battery using the voltage of the replaceable batteries by connecting multiple replaceable batteries to the input terminals of multiple DC-DC converters of the OBC that charge the main battery, without the need to install additional converters for the multiple replaceable batteries. This disclosure is not limited to the foregoing subject matter, and other subjects can be derived from the following description.

[0008] In one aspect of this disclosure, a vehicle charging system includes: a power factor correction unit that receives applied commercial AC power and corrects the power factor of the AC power; a plurality of link capacitors connected to the output terminals of the power factor correction unit; a plurality of converters having input terminals correspondingly connected to the link capacitors and converting voltages applied to the input terminals; a main battery that is charged using power converted by the plurality of converters; a plurality of replaceable batteries that are connected to the input terminals of the converters using switches; and a controller that applies voltages from the plurality of replaceable batteries to the input terminals of the plurality of converters by controlling the switches of the plurality of replaceable batteries according to whether commercial AC power is applied.

[0009] Multiple converters can be DC-DC converters whose topology can be modified in the form of a full bridge or a half bridge under the control of the controller.

[0010] When commercial AC power is applied to multiple converters, the controller can control multiple converters to operate as half-bridge converters.

[0011] With the voltage of multiple replaceable batteries applied to multiple converters, the controller can control multiple converters to operate as full-bridge converters.

[0012] The power factor correction unit can have the structure of a boost converter, and multiple link capacitors can be connected in series with each other at the output terminal of the boost converter.

[0013] The power factor correction unit can have a structure with multiple buck converters, and the link capacitor can be connected to the output terminal of the buck converter.

[0014] When commercial AC power is applied to the vehicle, the controller can control the switch to disconnect so that the main battery can be charged using commercial AC power.

[0015] When commercial AC power is not applied to the vehicle, the controller can control the switch to close to charge the main battery through multiple replaceable batteries.

[0016] The switch connected to the replaceable battery may include multiple relays, wherein the multiple relays include: a pre-charge relay, one end of which is connected to the positive terminal of the replaceable battery and initially charges multiple link capacitors; a first main relay, one end of which is connected to the positive terminal of the replaceable battery; and a second main relay, one end of which is connected to the negative terminal of the replaceable battery, and the first and second main relays, under the control of the controller, apply the voltage of the replaceable battery to the input terminal of the converter.

[0017] The converter's output can be connected in parallel to the main battery.

[0018] Multiple replaceable batteries may include multiple replaceable battery pairs, and the replaceable batteries in the multiple replaceable battery pairs may have output terminals that are connected to each other, and the output terminals that are connected to each other may be connected to the input terminals of the converter.

[0019] The controller can cause the two replaceable batteries to alternately charge the main battery by alternately opening and closing the switches of the two replaceable batteries in the replaceable battery pair.

[0020] In another aspect of this disclosure, a method for charging the main battery of a vehicle includes: determining, by a controller, whether commercial AC power is applied to the vehicle; when it is determined that commercial AC power has been applied to the vehicle, applying commercial AC power to the multiple converters by disconnecting switches connecting multiple replaceable batteries to multiple converters, the multiple converters converting the commercial AC power into a voltage for charging the main battery; and when it is determined that commercial AC power has not been applied to the vehicle, applying the voltage of the replaceable batteries to the multiple converters by closing switches.

[0021] Multiple converters can be DC-DC converters whose topology can be modified in the form of a full bridge or a half bridge under the control of a controller. Applying commercial AC power to multiple converters can include controlling multiple converters to operate as half bridge converters by the controller. Applying the voltage of a replaceable battery to multiple converters can include controlling multiple converters to operate as full bridge converters by the controller.

[0022] Because the OBC's DC-DC converters can be used, the main battery can be charged using the voltage of the replaceable batteries by connecting multiple replaceable batteries to the input terminals of the OBC's multiple DC-DC converters that charge the main battery, without the need to install additional converters for multiple replaceable batteries. This increases the vehicle's driving range and improves the efficiency of the motor and inverter. Attached Figure Description

[0023] The above and other objects, features and advantages of this disclosure will become clearer from the following detailed description taken in conjunction with the accompanying drawings, wherein:

[0024] Figure 1 This is an overall block diagram of a charging system according to an embodiment of the present disclosure;

[0025] Figure 2 This is a diagram illustrating a charging system according to an embodiment of the present disclosure;

[0026] Figure 3 This is a diagram illustrating a charging system according to another embodiment of the present disclosure;

[0027] Figure 4A and Figure 4BThis is a diagram illustrating the operation of a charging system according to an embodiment of the present disclosure;

[0028] Figure 5 This is a diagram illustrating a charging system according to another embodiment of the present disclosure; and

[0029] Figure 6 This is a flowchart illustrating a charging method according to an embodiment of the present disclosure. Detailed Implementation

[0030] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0031] This disclosure relates to a charging system and charging method for charging the main battery of a vehicle using a replaceable battery, which will be referred to as the “charging system” and the “charging method” in the following text.

[0032] Figure 1 This is an overall block diagram of a charging system according to an embodiment of the present disclosure.

[0033] Reference Figure 1 A charging system 100 according to an embodiment of the present disclosure includes: a power factor correction unit 120 that receives commercial AC power 110 applied from an external source and corrects the power factor of the AC power; a link capacitor unit 130 connected to the output terminal of the power factor correction unit 120; a DC-DC converter unit 140 having an input terminal connected to the link capacitor unit 130 and converting the voltage applied to its input terminal; a main battery 150 that is charged using the voltage converted by the DC-DC converter unit 140; a replaceable battery unit 170 connected between the link capacitor unit 130 and the DC-DC converter unit 140 via a switching unit 160; and a controller that controls the DC-DC converter unit 140 and the switching unit 160 depending on whether commercial AC power 110 is applied.

[0034] The power factor correction unit 120 is configured to correct the power factor of an externally applied commercial AC power supply 110 and output a corrected voltage. It can consist of one or more converters and can also be configured as a bridgeless topology if needed.

[0035] Link capacitor unit 130 is configured such that multiple link capacitors 131, 132, and 133 are connected to the output terminals of one or more converters of power factor correction unit 120. In this case, in order to connect DC-DC converter unit 140, which consists of multiple DC-DC converters, to the back end of power factor correction unit 120, the multiple link capacitors 131, 132, and 133 preferably have the same size.

[0036] The DC-DC converter unit 140 may consist of multiple DC-DC converters that convert the voltage applied to the input terminals into a voltage for charging the main battery 150 to output the converted voltage. In this case, preferably, an isolated converter is used as the DC-DC converter.

[0037] Furthermore, in embodiments of this disclosure, if the DC-DC converter unit 140 consists of a DC-DC converter whose topology can be modified in the form of a full bridge or a half bridge, the main battery 150 can be charged more efficiently by modifying the topology according to the type of charging source that charges the main battery 150 (i.e., external commercial AC power supply 110 or replaceable batteries 171, 172 and 173).

[0038] The replaceable battery unit 170 may consist of multiple replaceable batteries 171, 172, and 173, and is connected between the link capacitor unit 130 and the DC-DC converter unit 140 via a switching unit 160. The replaceable battery unit 170 is a voltage source for charging the main battery 150 when it is not being charged by the commercial AC power supply 110. The voltage supply from the replaceable battery unit 170 is controlled by controlling the switching unit 160 connected to it.

[0039] The controller 180 can change the topology of the DC-DC converter unit 140 by controlling the on / off state of the switches constituting the DC-DC converter unit 140 according to whether commercial AC power supply 110 is applied, and can control the voltage supply from the replaceable battery unit 170 by controlling the on / off state of the switching unit 160 of the replaceable battery unit 170.

[0040] The controller 180 described above can be implemented in the form of a microcomputer, which includes a processor for performing algorithmic processing and calculations required for control, and a memory for storing the information required by the processor for algorithmic processing and calculations.

[0041] According to embodiments of this disclosure, the replaceable battery cell 170 that charges the main battery 150 is not connected to the main battery 150 via a separate converter, but is connected to the main battery 150 via a DC-DC converter unit 140 that converts existing commercial AC power 110. When no commercial AC power 110 is applied, the DC-DC converter unit 140 converts the voltage from the replaceable battery cell 170 and supplies the converted voltage to the main battery 150, making the charging system economical and having excellent charging efficiency.

[0042] In the following, various configurations of the charging system according to the present disclosure will be described in detail through various embodiments.

[0043] Example 1

[0044] Example 1 is Figure 1 An embodiment of the power factor correction unit 120 consisting of a single converter. Figure 2 This is a diagram showing the charging system according to Embodiment 1.

[0045] Reference Figure 2 The charging system according to an embodiment of the present disclosure comprises a power factor correction converter 121, a plurality of link capacitors 131, 132 and 133, a plurality of DC-DC converters 141, 142 and 143, a main battery 150, a plurality of switches 161, 162 and 163 and a plurality of replaceable batteries 171, 172 and 173.

[0046] The power factor correction converter 121 is configured as a single boost converter topology. In embodiments of this disclosure, the power factor correction converter 121 may be configured as a bridgeless topology. This boost converter topology is advantageous because it can improve the power factor (PF) and reduce total harmonic distortion (THD).

[0047] Multiple link capacitors 131, 132, and 133 are of the same size and are connected in series to the output terminal of the power factor correction converter 121. The link capacitors 131, 132, and 133 connected in series with each other can provide a stable voltage supply to match the voltage of replaceable batteries 171, 172, and 173, respectively.

[0048] Multiple DC-DC converters 141, 142, and 143 are connected one-to-one with link capacitors 131, 132, and 133 to receive the voltage input from the multiple link capacitors 131, 132, and 133 connected in series with each other. (Refer to...) Figure 3 Since the first DC-DC converter 141 is connected to receive the input voltage applied to the first link capacitor 131, the second DC-DC converter 142 is connected to receive the input voltage applied to the second link capacitor 132, and the third DC-DC converter 143 is connected to receive the input voltage applied to the third link capacitor 133, the link capacitors 131, 132, and 133 correspond one-to-one with the DC-DC converters 141, 142, and 143. The outputs of the multiple DC-DC converters 141, 142, and 143 are connected in parallel with each other and input to the input terminal of the main battery 150.

[0049] Multiple DC-DC converters 141, 142, and 143 can be composed of DC-DC converters whose topology can be modified in full-bridge or half-bridge form, and can be correctly selected and used by a person of ordinary skill if the detailed circuit configuration can be modified in full-bridge or half-bridge form under the control of the controller.

[0050] Figure 4A and Figure 4B This is a diagram illustrating examples of DC-DC converters 141, 142, and 143, where the topology can be modified in either a full-bridge or half-bridge configuration. (See also...) Figure 4A According to this embodiment, the converter may be a converter including a full-bridge structure, wherein the input terminals of the converter have first to fourth switches 410, 420, 430 and 440.

[0051] According to the converter including this full-bridge structure, the operation of the first to fourth switches 410, 420, 430 and 440 is controlled by the controller 180, so the topology can be modified in the form of a full-bridge or half-bridge.

[0052] Figure 4A This illustrates a scenario where a DC-DC converter operates as a full-bridge converter via conventional full-bridge switch control (first switch / fourth switch control and second switch / third switch control). Figure 4B The diagram illustrates a scenario where the DC-DC converter operates as a half-bridge converter in such a manner that the second switch 420 is always turned off by the controller to disconnect the connection of the second switch 420, and the fourth switch 440 is always turned on to short-circuit the connection of the fourth switch 440.

[0053] Multiple replaceable batteries 171, 172, and 173 are connected to DC-DC converters 141, 142, and 143 via switches 161, 162, and 163, respectively. More specifically, see [reference needed]. Figure 2 Since the first replaceable battery 171 is connected to the input terminal of the first DC-DC converter 141 via the first switch 161, the second replaceable battery 172 is connected to the input terminal of the second DC-DC converter 142 via the second switch 162, and the third replaceable battery 173 is connected to the input terminal of the third DC-DC converter 143 via the third switch 163, the voltages from the replaceable batteries 171, 172, and 173 can be applied to the DC-DC converters 141, 142, and 143, respectively.

[0054] Multiple switches 161, 162, and 163 can be disconnected or short-circuited under the control of controller 180 to apply or not apply voltages from multiple replaceable batteries 171, 172, and 173 to multiple DC-DC converters 141, 142, and 143, respectively.

[0055] If switches 161, 162, and 163 can control the application of voltage from replaceable batteries 171, 172, and 173, they can be properly selected and used by a person of ordinary skill.

[0056] According to embodiments of this disclosure, switches 161, 162, and 163 may consist of multiple relays. (See also...) Figure 2 According to embodiments of the present disclosure, switches 161, 162, and 163 may consist of three relays. Each relay may be a pre-charge relay with one end connected to the positive terminal (anode) of replaceable batteries 171, 172, and 173 and initially charging link capacitors 131, 132, and 133 connected to the other end of the relay; a first main relay with one end connected to the positive terminal of replaceable batteries 171, 172, and 173; and a second main relay with one end connected to the negative terminal (cathode) of replaceable batteries.

[0057] When replaceable batteries 171, 172, and 173 begin charging the main battery 150, a pre-charge relay first closes to initially charge the link capacitors 131, 132, and 133 connected to them. Subsequently, if charging of the connected link capacitors 131, 132, and 133 is complete, the pre-charge relay opens and the first main relay closes, so that the voltage from replaceable batteries 171, 172, and 173 is applied to DC-DC converters 141, 142, and 143.

[0058] The following will describe according to Figure 2 The operation of the charging system in the illustrated embodiment.

[0059] If the vehicle is currently being charged by commercial AC power 110 applied from the outside, multiple switches 161, 162 and 163 are disconnected under the control of controller 180.

[0060] When multiple switches 161, 162, and 163 are open, the circuit between multiple replaceable batteries 171, 172, and 173 and multiple DC-DC converters 141, 142, and 143 is disconnected. Therefore, the voltage from the multiple replaceable batteries 171, 172, and 173 is not applied to the multiple DC-DC converters 141, 142, and 143, and the vehicle's main battery 150 is charged by an external commercial AC power supply 110 that is converted by the multiple DC-DC converters 141, 142, and 143.

[0061] On the other hand, if the main battery 150 needs to be charged when there is no external commercial AC power supply 110, multiple switches 161, 162 and 163 are closed by the controller 180.

[0062] When multiple switches 161, 162, and 163 are closed, the circuit between multiple replaceable batteries 171, 172, and 173 and multiple DC-DC converters 141, 142, and 143 is short-circuited. Therefore, the voltage of the replaceable batteries 171, 172, and 173 is applied as input to the DC-DC converters 141, 172, and 173 connected to the replaceable batteries 171, 172, and 173, and the vehicle's main battery 150 is charged by the voltage of the multiple replaceable batteries 171, 172, and 173 that has been converted by the multiple DC-DC converters 141, 142, and 143.

[0063] In embodiments of this disclosure, multiple DC-DC converters 141, 142, and 143 can be controlled by controller 180 to operate as half-bridge converters when the main battery 150 is charged by commercial AC power supply 110, and can also be controlled by controller 180 to operate as full-bridge converters when the main battery 150 is charged by multiple replaceable batteries 171, 172, and 173. As described above, since the operation of the DC-DC converters is modified according to the charging source for charging the main battery 150, charging of the main battery by different charging sources can be stably performed.

[0064] According to the charging system 100 of this embodiment, since the replaceable batteries 171, 172, and 173 used to charge the main battery 150 charge the main battery 150 through a DC-DC converter unit 140 that converts existing commercial AC power 110, the charging system is economical and has excellent charging efficiency. Furthermore, since the power factor correction converter 121 with a boost converter structure performs power factor correction on the external commercial AC power 110, the power factor can be improved and total harmonic distortion can be reduced.

[0065] Furthermore, since DC-DC converters 141, 142, and 143 are respectively connected to multiple link capacitors 131, 132, and 133 connected in series to the output terminals of power factor correction converter 121, they have the technical effect of allowing the voltages of the matching replaceable batteries 171, 172, and 173 to be applied to DC-DC converters 141, 142, and 143, respectively.

[0066] Example 2

[0067] Example 2 is Figure 1 An embodiment of the power factor correction unit 120 is composed of multiple converters. Figure 3 This is a diagram illustrating a charging system according to Embodiment 2 of the present disclosure.

[0068] Reference Figure 3The charging system according to an embodiment of the present disclosure comprises a plurality of power factor correction converters 122, 123 and 124, a plurality of link capacitors 131, 132 and 133, a plurality of DC-DC converters 141, 142 and 143, a main battery 150, a plurality of switches 161, 162 and 163 and a plurality of replaceable batteries 171, 172 and 173.

[0069] Multiple power factor correction converters 122, 123, and 124 consist of multiple buck converters connected in parallel with each other. In embodiments of this disclosure, the multiple power factor correction converters 122, 123, and 124 can be configured in a bridgeless topology.

[0070] When the buck converter is used as a power factor correction converter 122, 123 and 124, the multiple link capacitors 131, 132 and 133 connected to the output terminals of the buck converter can be used as film capacitors, which can increase the life of the charging system 100 and improve the power density.

[0071] Multiple link capacitors 131, 132 and 133 are connected to the output terminals of power factor correction converters 122, 123 and 124 in a one-to-one correspondence.

[0072] The controller 180 can control the voltage applied to the link capacitors 131, 132, and 133 to match the voltages of the multiple replaceable batteries 171, 172, and 173. For example, in an embodiment of this disclosure, if the voltage of the replaceable batteries 171, 172, and 173 is 48V, the controller 180 can control the voltage applied to the link capacitors 131, 132, and 133 to be between 50V and 80V.

[0073] Multiple DC-DC converters 141, 142, and 143 are connected to link capacitors 131, 132, and 133 in a one-to-one correspondence, and the voltage applied to the two terminals of each of the link capacitors 131, 132, and 133 is applied to the input terminals of the DC-DC converters 141, 142, and 143.

[0074] Reference Figure 3 Since the first DC-DC converter 141 is connected to receive the input voltage of the first link capacitor 131 applied to the first power factor correction converter 122, the second DC-DC converter 142 is connected to receive the input voltage of the second link capacitor 132 applied to the second power factor correction converter 123, and the third DC-DC converter 143 is connected to receive the input voltage of the third link capacitor 133 applied to the third power factor correction converter 124, the link capacitors 131, 132, and 133 correspond to the DC-DC converters 141, 142, and 143 in a one-to-one manner.

[0075] The outputs of multiple DC-DC converters 141, 142, and 143 are connected in parallel and input to the input terminal of the main battery 150.

[0076] Multiple DC-DC converters 141, 142, and 143 can be composed of DC-DC converters whose topology can be modified in full-bridge or half-bridge form, and can be correctly selected and used by a person of ordinary skill if the detailed circuit configuration can be modified in full-bridge or half-bridge form under the control of the controller.

[0077] Multiple replaceable batteries 171, 172, and 173 are connected to DC-DC converters 141, 142, and 143 via switches 161, 162, and 163, respectively. More specifically, see [reference needed]. Figure 3 Since the first replaceable battery 171 is connected to the input terminal of the first DC-DC converter 141 via the first switch 161, the second replaceable battery 172 is connected to the input terminal of the second DC-DC converter 142 via the second switch 162, and the third replaceable battery 173 is connected to the input terminal of the third DC-DC converter 143 via the third switch 163, the voltages from the replaceable batteries 171, 172, and 173 can be applied to the DC-DC converters 141, 142, and 143, respectively.

[0078] Multiple switches 161, 162, and 163 can be disconnected or short-circuited under the control of controller 180 to apply or not apply voltages from multiple replaceable batteries 171, 172, and 173 to multiple DC-DC converters 141, 142, and 143, respectively.

[0079] If the vehicle is currently being charged by commercial AC power 110 applied from the outside, multiple switches 161, 162 and 163 are disconnected under the control of controller 180.

[0080] When multiple switches 161, 162, and 163 are open, the circuit between multiple replaceable batteries 171, 172, and 173 and multiple DC-DC converters 141, 142, and 143 is disconnected. Therefore, the voltage from the multiple replaceable batteries 171, 172, and 173 is not applied to the multiple DC-DC converters 141, 142, and 143, and the vehicle's main battery 150 is charged by an external commercial AC power supply 110 converted by the multiple DC-DC converters 141, 142, and 143.

[0081] On the other hand, if the main battery 150 needs to be charged when there is no external commercial AC power supply 110, multiple switches 161, 162 and 163 are closed by the controller 180.

[0082] When multiple switches 161, 162, and 163 are closed, the circuit between multiple replaceable batteries 171, 172, and 173 and multiple DC-DC converters 141, 142, and 143 is short-circuited. Therefore, the voltage of the replaceable batteries 171, 172, and 173 is applied as input to the DC-DC converters 141, 142, and 143 connected to the replaceable batteries 171, 172, and 173, and the vehicle's main battery 150 is charged by the voltage of the multiple replaceable batteries 171, 172, and 173 that has been converted by the multiple DC-DC converters 141, 142, and 143.

[0083] According to the charging system 100 of this embodiment, since the replaceable batteries 171, 172, and 173 used to charge the main battery 150 charge the main battery 150 through a DC-DC converter unit 140 that converts existing commercial AC power 110, the charging system is economical and has excellent charging efficiency. Furthermore, since multiple power factor correction converters 122, 123, and 124 with buck converter structures perform power factor correction for the external commercial AC power 110, the lifespan of the charging system can be increased.

[0084] Example 3

[0085] Example 3 illustrates a charging system 100 in which a greater number of replaceable batteries 171, 172, 173, 174, 175, and 176 are installed than the number of DC-DC converters 141, 142, and 143.

[0086] Figure 5 The configuration of the charging system according to Embodiment 3 is shown. In Embodiment 3, the number of replaceable batteries 171, 172, 173, 174, 175 and 176 is increased in the charging system according to Embodiment 1. The configuration of the charging system is the same as that according to Embodiment 1, except that the number of replaceable batteries 171, 172, 173, 174, 175 and 176 is different.

[0087] Although the power factor correction unit 120 in Embodiment 3 is Figure 5 While shown as a single power factor correction converter 121, it will be apparent to those skilled in the art that the same effect can be achieved even if the power factor correction unit 120 consists of multiple power factor correction converters 122, 123, and 124 as in Embodiment 2.

[0088] Reference Figure 5The output terminals of the first replaceable battery 171 and the fourth replaceable battery 174, the output terminals of the second replaceable battery 172 and the fifth replaceable battery 175, and the output terminals of the third replaceable battery 173 and the sixth replaceable battery 176 are connected to each other. The input terminals of the DC-DC converters 141, 142, and 143 are connected to the output terminals of the replaceable batteries 171, 172, 173, 174, 175, and 176.

[0089] When the main battery 150 is charged by multiple replaceable batteries 171, 172, and 173, the controller 180 can operate to close switches 161, 162, and 163 connected to some of the replaceable battery pairs (e.g., the first, second, and third replaceable batteries) and open switches 164, 165, and 166 connected to other replaceable batteries (e.g., the fourth, fifth, and sixth replaceable batteries) to alternately charge the main battery 150 among the replaceable battery pairs 171, 172, 173, 174, 175, and 176.

[0090] As described above, when a greater number of replaceable batteries 171, 172, 173, 174, 175, and 176 than the number of DC-DC converters 141, 142, and 143 are connected to multiple DC-DC converters 141, 142, and 143, after connecting the output terminals of the replaceable battery pairs 171, 172, 173, 174, 175, and 176 to each other and connecting the connected output terminals to the input terminals of multiple DC-DC converters 141, 142, and 143, the main battery is charged by alternately opening and closing the switches of the replaceable battery pairs 171, 172, 173, 174, 175, and 176. Therefore, replaceable batteries can be added without any separation of the multiple DC-DC converters 141, 142, and 143, thereby increasing the vehicle's driving time economically and easily.

[0091] Figure 6 This is a flowchart illustrating a method for charging a vehicle battery according to an embodiment of the present disclosure.

[0092] Reference Figure 6 In step 610, the controller 180 determines whether an external commercial AC power supply 110 is applied to the vehicle.

[0093] If the controller determines in step 610 that an external commercial AC power source 110 is applied to the vehicle, then in step 620, the controller 180 controls a plurality of switches 161, 162 and 163 connected to a plurality of replaceable batteries 171, 172 and 173 to apply power from the commercial AC power source 110 to the main battery 150.

[0094] In embodiments of this disclosure, controller 180 can control the application of commercial AC power to multiple converters 141, 142, 143, and 144 by disconnecting the connection between multiple replaceable batteries 171, 172, and 173 and multiple DC-DC converters 141, 142, and 143 via a disconnect switch, wherein the multiple replaceable batteries are connected to the multiple DC-DC converters 141, 142, and 143 via the switch, and the multiple DC-DC converters 141, 142, and 143 convert commercial AC power 110 into a voltage for charging main battery 150.

[0095] In this configuration, the controller can control the DC-DC converters 141, 142, and 143 to operate as half-bridge converters by controlling multiple switches configured on the input terminals of the DC-DC converters 141, 142, and 143.

[0096] If the controller determines in step 610 that external commercial AC power 110 is not being applied to the vehicle, then in step 630, the controller 180 can apply the voltages of the multiple replaceable batteries 171, 172, and 173 to the multiple DC-DC converters 141, 142, and 143 by connecting the multiple replaceable batteries 171, 172, and 173 to the multiple DC-DC converters 141, 142, and 143 via closing multiple switches connected to the multiple replaceable batteries 171, 172, and 173. The voltages of the multiple replaceable batteries 171, 172, and 173 applied to the multiple DC-DC converters 141, 142, and 143 are converted to charge the main battery 150.

[0097] In this configuration, the controller can control the DC-DC converters 141, 142, and 143 to operate as full-bridge converters by controlling multiple switches configured on the input terminals of the DC-DC converters 141, 142, and 143.

[0098] The system and method for charging a vehicle battery according to embodiments of the present disclosure increase the vehicle's driving range and improve the efficiency of the motor and inverter because the main battery can be charged using the voltage of the replaceable batteries by connecting multiple replaceable batteries to the input terminals of multiple DC-DC converters of the OBC that charge the main battery, without the need to install additional converters for multiple replaceable batteries.

[0099] The present disclosure has been described so far with regard to preferred embodiments. Those skilled in the art will understand that the present disclosure can be implemented in modified forms without departing from the inherent characteristics of the present disclosure. Therefore, the disclosed embodiments should not be considered as limiting, but rather as interpretive. The scope of the present disclosure is not set forth in the foregoing description, but rather in the appended claims, and all variations within the equivalent scope should be understood to be included in this disclosure.

[0100] While many exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize that further modifications, substitutions, additions, and sub-combinations of the features of the disclosed embodiments are still possible. Therefore, the appended and introduced claims are intended to be construed as including all such modifications, substitutions, additions, and sub-combinations within their true spirit and scope.

Claims

1. A system for charging a vehicle battery, the system comprising: A power factor correction unit is configured to receive an applied commercial AC power supply and to correct the power factor of the AC power supply. Multiple link capacitors are connected to the output terminals of the power factor correction unit; Multiple converters, each converter having its input terminal connected one-to-one to each of the multiple link capacitors, and configured to convert the voltage applied to the input terminal; The main battery is configured to be charged using power converted by the plurality of converters; Multiple replaceable batteries are connected to the input terminals of the converter using a switch; as well as The controller applies the commercial AC power or the voltage of the multiple replaceable batteries to the input terminals of the multiple converters by controlling the switching of the multiple replaceable batteries based on whether the commercial AC power is applied.

2. The system of claim 1, wherein the plurality of converters are DC-DC converters whose topology can be modified in the form of a full bridge or a half bridge under the control of the controller.

3. The system of claim 2, wherein the controller is configured to control the plurality of converters to operate as half-bridge converters when the commercial AC power supply is applied to the plurality of converters.

4. The system of claim 2, wherein the controller is configured to control the plurality of converters to operate as full-bridge converters when the voltage of the plurality of replaceable batteries is applied to the plurality of converters.

5. The system of claim 1, wherein the power factor correction unit has the structure of a boost converter, and The multiple link capacitors are connected in series with each other at the output terminal of the boost converter.

6. The system of claim 1, wherein the power factor correction unit has a structure of multiple buck converters, and Each of the multiple link capacitors is connected to the output terminal of the buck converter.

7. The system of claim 1, wherein the controller is configured to control the switch to disconnect to charge the main battery using the commercial AC power when the commercial AC power is applied to the vehicle.

8. The system of claim 1, wherein the controller is configured to control the switch to close to charge the main battery through the plurality of replaceable batteries when the commercial AC power is not applied to the vehicle.

9. The system of claim 1, wherein each switch connected to the replaceable battery comprises a plurality of relays. The plurality of relays mentioned above include: A pre-charge relay, one end of which is connected to the positive terminal of the replaceable battery, and initially charges the plurality of link capacitors; The first main relay has one end connected to the positive terminal of the replaceable battery; And a second main relay, one end of which is connected to the negative terminal of the replaceable battery, and The first main relay and the second main relay, under the control of the controller, apply the voltage of the replaceable battery to the input terminal of the converter.

10. The system of claim 1, wherein the output of the converter is connected in parallel to the main battery.

11. The system of claim 1, wherein the plurality of replaceable batteries comprises a plurality of replaceable battery pairs, and The replaceable batteries in the plurality of replaceable battery pairs have output terminals that are connected to each other, and the output terminals that are connected to each other are connected to the input terminals of the converter.

12. The system of claim 11, wherein the controller causes the two replaceable batteries to alternately charge the main battery by alternately opening and closing the switches of two of the plurality of replaceable battery pairs.

13. A method for charging the main battery of a vehicle, the method comprising: The controller determines whether commercial AC power is applied to the vehicle; When it is determined that the commercial AC power has been applied to the vehicle, the controller applies the commercial AC power to the multiple converters by disconnecting the switches connecting the multiple replaceable batteries to the multiple converters. The multiple converters then convert the commercial AC power into a voltage for charging the main battery. When it is determined that the commercial AC power has not yet been applied to the vehicle, the controller applies the voltage of the replaceable battery to the plurality of converters by closing the switch.

14. The method of claim 13, wherein the plurality of converters are DC-DC converters whose topology can be modified in a full-bridge or half-bridge configuration under the control of the controller. Applying the commercial AC power to the plurality of converters includes the controller controlling the plurality of converters to operate as half-bridge converters, and Applying the voltage of the replaceable battery to the plurality of converters includes the controller controlling the plurality of converters to operate as half-bridge converters.

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