Electric vehicle

An electric vehicle includes: a battery configured to be charged with a first voltage; and a converter configured to boost, when power of a second voltage that is lower than the first voltage is received, the power of the second voltage to the first voltage, and to transfer the first voltage to the battery, so that the battery is charged with power of the first voltage, wherein when the power of the first voltage is received, the power of the first voltage is transferred to the battery to charge the battery.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Korean Patent Application No. 10-2017-0092450, filed on Jul. 21, 2017 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a vehicle, and more particularly, to an electric vehicle of traveling using power of a motor.

BACKGROUND

An electric vehicle uses electrical energy as a main energy source, unlike an internal-combustion engine vehicle using fossil fuel as a main energy source. Accordingly, the electric vehicle essentially needs a high-voltage battery to store electrical energy, a motor as a power source, and an inverter to drive the motor. In order to increase a driving distance and efficiency of power consumption of the electric vehicle, use of a large-capacity battery is increasing. Further, efforts for increasing the efficiency of the inverter and the motor are actively conducted.

One of methods for improving the efficiency of the inverter and the motor is to raise a battery voltage. For example, doubling a battery voltage can reduce current flowing to the inverter and the motor to ½ to obtain the same output power since P=VI, and can reduce conduction loss (I2R) to ¼. Accordingly, the efficiency of the inverter and the motor can increase by the amount of reduction of the conduction loss. If a power element and a conductor having high conduction resistance are used, the sizes of connection connectors connecting the battery, the inverter, and the motor, as well as the sizes of the inverter and the motor can be reduced, which leads to a reduction of cost.

However, increasing a battery voltage has one limitation. Most of commercialized rapid chargers charge batteries having a charging voltage of about 200V to 500V. Accordingly, a battery having a high charging voltage of 800V or more for high efficiency cannot be charged by typical rapid chargers that charge batteries having a charging voltage of 200V to 500V. That is, compatibility with the typical rapid chargers acts as a limiting factor in raising the battery voltage of the electric vehicle. For this reason, a rapid charger capable of outputting (charging) a high voltage should be developed and installed in order to raise the battery voltage of the electric vehicle.

SUMMARY

An aspect of the present disclosure provides a converter for converting power between a charger installed in a charging facility and a battery of an electric vehicle so as to achieve the compatibility between a rapid charger and a high-voltage battery.

In accordance with one aspect of the present disclosure, an electric vehicle includes: a battery configured to be charged with a first voltage; and a converter configured to boost, when power of a second voltage that is lower than the first voltage is received, the power of the second voltage to the first voltage, and to transfer the first voltage to the battery so that the battery is charged with power of the first voltage, wherein when the power of the first voltage is received, the power of the first voltage is transferred to the battery to charge the battery.

The electric vehicle may further include a switch disposed at an input side of the converter, and configured to open or close a path through which the power of the second voltage received is transferred to the converter and the battery.

The switch includes: a first switch configured to be turned on when the power of the first voltage is received so that the power of the first voltage is transferred to the battery; and a second switch and a third switch configured to be turned on when the power of the second voltage is received so that the power of the second voltage is boosted by the converter and then transferred to the battery.

The switch includes: a diode configured to directly transfer the power of the first voltage received to the battery; and a second switch and a third switch configured to be turned on when the power of the second voltage is received so that the power of the second voltage is boosted by the converter and then transferred to the battery.

In the electric vehicle, the switch may be selectively turned on and off in a charging mode, and in a driving mode, the switch may be turned off.

The switch is disposed inside the converter.

The switch is disposed outside the converter.

In accordance with another aspect of the present disclosure, an electric vehicle includes: a battery configured to be charged with a first voltage; a motor configured to drive a driving wheel; and an inverter configured to convert power of the battery, and to provide the power of the battery to the motor, wherein when power of a second voltage that is lower than the first voltage is received, the motor and the inverter operate as a converter to boost the power of the second voltage to the first voltage, and to transfer the first voltage to the battery so that the battery is charged with power of the first voltage, and when power of the first voltage is received, the power of the first voltage is transferred to the battery so that the battery is charged with the power of the first voltage.

The electric vehicle further includes a switch configured to open or close a path through which the power of the second voltage received is transferred to the inverter and the motor.

The switch includes a first switch configured to be turned on when the power of the first voltage is received so that the power of the first voltage is transferred to the battery through the inverter; and a second switch and a third switch configured to be turned on when the power of the second voltage is received so that the power of the second voltage is boosted by the inverter and the motor and then transferred to the battery.

The switch includes a diode configured to transfer the power of the first voltage received to the inverter; and a second switch and a third switch configured to be turned on when the power of the second voltage is received so that the power of the second voltage is boosted by the inverter and the motor and then transferred to the battery.

In the electric vehicle, the switch may be selectively turned on and off in a charging mode, and in a driving mode, the switch may be turned off.

In accordance with another aspect of the present disclosure, an electric vehicle includes: a battery configured to be charged with a first voltage; a motor configured to drive a driving wheel; an inverter configured to convert power of the battery, and to provide the power of the battery to the motor; a switch configured to open or close a path through which power received is transferred to the inverter and the motor; and an external inductor configured to connect the switch to the motor, wherein when power of a second voltage that is lower than the first voltage is received, the motor and the inverter operate as a converter to boost the power of the second voltage to the first voltage, and to transfer the first voltage to the battery so that the battery is charged with power of the first voltage, and when power of the first voltage is received, the power of the first voltage is transferred to the battery so that the battery is charged with the power of the first voltage.

The switch includes a first switch configured to be turned on when the power of the first voltage is received so that the power of the first voltage is transferred to the battery through the inverter; and a second switch and a third switch configured to be turned on when the power of the second voltage is received so that the power of the second voltage is boosted by the inverter and the motor and then transferred to the battery.

The switch includes a diode configured to transfer the power of the first voltage received to the inverter; and a second switch and a third switch configured to be turned on when the power of the second voltage is received so that the power of the second voltage is boosted by the inverter and the motor and then transferred to the battery.

In the electric vehicle, the switch may be selectively turned on and off in a charging mode, and in a driving mode, the switch may be turned off.

The external inductor is connected to a neutral terminal of the motor.

In accordance with another aspect of the present disclosure, an electric vehicle includes: a battery configured to be charged with a first voltage; a motor configured to drive a driving wheel; an inverter configured to convert power of the battery, and to provide the power of the battery to the motor; and a switch disposed in the inverter to be integrated into the inverter, and configured to open or close a path through which power received is transferred to the inverter and the motor, wherein when power of a second voltage that is lower than the first voltage is received, the motor and the inverter operate as a converter to boost the power of the second voltage to the first voltage, and to transfer the first voltage to the battery so that the battery is charged with power of the first voltage, and when power of the first voltage is received, the power of the first voltage is transferred to the battery so that the battery is charged with the power of the first voltage.

In accordance with another aspect of the present disclosure, an electric vehicle includes: a battery configured to be charged with a first voltage; and a converter configured to boost, when power of a second voltage that is lower than the first voltage is received, the power of the second voltage to the first voltage, and to transfer the first voltage to the battery.

In accordance with another aspect of the present disclosure, an electric vehicle includes: a battery configured to be charged with a first voltage; a motor configured to drive a driving wheel; and an inverter configured to convert power of the battery, and to provide the power of the battery to the motor, wherein when power of a second voltage that is lower than the first voltage is received, the motor and the inverter operate as a converter to boost the power of the second voltage to the first voltage and to transfer the first voltage to the battery.

DETAILED DESCRIPTION

FIG. 1shows an electric vehicle according to an embodiment of the present disclosure.

Referring toFIG. 1, an electric vehicle100may include a motor (see212ofFIG. 2). Accordingly, the electric vehicle100may need a high-voltage battery to store power for driving the motor212. An internal-combustion engine vehicle also includes an auxiliary battery (see208ofFIG. 2) in an engine room. However, the electric vehicle100may require a large-capacity high-voltage battery102having a large size. In the electric vehicle100according to the present disclosure, the high-voltage battery102may be installed in space under a passenger seat of a second row. Electricity stored in the high-voltage battery102may drive the motor212to generate power. The high-voltage battery102according to the present disclosure may be a lithium battery.

The electric vehicle100may include a charging socket104. The charging socket104may connect to a charging connector152installed in an external charging facility to charge the high-voltage battery102. That is, the high-voltage battery102of the electric vehicle100may be charged by connecting the charging connector152installed in the external charging facility to the charging socket104of the electric vehicle100.

FIG. 2is a block diagram of a power supply apparatus of an electric vehicle according to an embodiment of the present disclosure. The power supply apparatus shown inFIG. 2may be used to supply power to the motor212and an electric field load214.

As shown inFIG. 2, the power supply apparatus of the electric vehicle100according to an embodiment of the present disclosure may include the high-voltage battery102, a Low Voltage DC-DC Converter (LDC)204, an inverter206, an auxiliary battery208, and a controller210.

The LDC204may convert a high DC voltage of the high-voltage battery102into a lower DC voltage. More specifically, the LDC204may convert a high DC voltage of the high-voltage battery102into an AC voltage, step down the AC voltage through a coil, a transformer, a capacitor, etc., and then rectify the step-down voltage, thereby converting the high DC voltage to a lower DC voltage. The DC voltage stepped down by the LDC204may be supplied to the electric field load214that requires a low voltage.

A DC voltage from the high-voltage battery102may be converted into an AC voltage having a predetermined phase and a predetermined frequency by the inverter206, and then supplied to the motor212. Torque and rotational speed of the motor212may depend on an output voltage of the inverter206. The controller210may control overall operations of the power supply apparatus.

FIG. 3is a block diagram of a charging apparatus of an electric vehicle according to an embodiment of the present disclosure.

In order to charge the high-voltage battery102of the electric vehicle100, various kinds of external chargers including a first rapid charger352, a second rapid charger354, and a slow charger356may be used. The high-voltage battery102may have a charging voltage of 500V to 800V.

The first rapid charger352may charge the high-voltage battery102with a first voltage (for example, a high DC voltage of 800V). The first rapid charger352may convert commercial AC power into a DC voltage of 800V, and supply the DC voltage of 800V to the electric vehicle100.

The second rapid charger354may charge the high-voltage battery102with a second voltage (for example, a DC voltage of 400V) that is lower than the first voltage of 800V. The second rapid charger354may convert the commercial AC power into a DC voltage of 400V, and supply the DC voltage of 400V to the electric vehicle100.

The slow charger356may supply the commercial AC power as it is to the electric vehicle100. The AC power supplied through the slow charger356may be converted into a DC voltage of a predetermined level in the electric vehicle100.

In the electric vehicle100, an on-board charger (OBC)302and a converter304may be involved in charging the high-voltage battery102.

The on-board charger302called OBC may convert the commercial AC power supplied from the slow charger356into a DC voltage of 800V so as to charge the high-voltage battery102. While the first rapid charger352and the second rapid charger354convert an AC voltage into a DC voltage and supply the DC voltage to the electric vehicle100, the slow charger356may supply commercial AC power as it is to the electric vehicle100. The AC voltage supplied from the slow charger356may be converted into a DC voltage by the on-board charger302in the electric vehicle100, and then used to charge the high-voltage battery102.

When a voltage supplied from an external charger is too low to charge the high-voltage battery102, the converter304may boost the voltage supplied from the external charger to a high level enough to charge the high-voltage battery102. As shown inFIG. 3, if the high-voltage battery102has a very high charging voltage of 500V to 800V, the second rapid charger354of providing a DC voltage of 400V cannot charge the high-voltage battery102of the electric vehicle100. In this case, according to the present disclosure, the converter304(that is, a boosting converter) for boosting a DC voltage of 400V to 800V may be used to boost the voltage of 400V supplied from the second rapid charger354to 800V. The voltage boosted by the converter304may be used to charge the high-voltage battery102.

A DC voltage of 800V supplied from the first rapid charger352may be provided as it is to the high-voltage battery102. Since the high-voltage battery102has a charging voltage of 500V to 800V, the DC voltage of 800V supplied from the first rapid charger352can be used to charge the high-voltage battery102without having to be boosted.

FIG. 4shows a first embodiment of a charging apparatus of an electric vehicle according to the present disclosure. A converter304shown inFIG. 4may boost, like the converter304ofFIG. 3, a DC voltage of 400V supplied from the second rapid charger354outside the electric vehicle100to 800V so as to charge the high-voltage battery102.

A capacitor C connected in parallel to input terminals of the converter304may remove ripples of a DC voltage that is input to the converter304.

A combination of inverters L1, L2, and L3, diodes D1, D2, and D3, and switches S1, S2, and S3may constitute a boost circuit to boost an input voltage of 400V to generate an output voltage of 800V. The inverter L1, the diode D1, and the switch S1may form a first group to boost an input voltage. That is, when the switch S1is in a turned-off state, current may flow to the inductor L1to store energy. In this state, if the switch S1is turned on, current may no longer flow to the inductor L1so that the energy stored in the inductor L1is transferred to the high-voltage battery102through the diode D1. An output voltage of the converter304may be always higher than an input voltage of the converter304. Further, the inverter L2, the diode D2, and the switch S2may form a second group, and the inverter L3, and the diode D3, and the switch S3may form a third group. The second and third groups may operate in the same manner as the first group of the inverter L1, the diode D1, and the switch S1.

The characteristics of the converter304are shown inFIGS. 5A-5D.

FIGS. 5A-5Dare graphs showing electrical characteristics of a converter according to an embodiment of the present disclosure.FIGS. 5A-5Crepresent signals for controlling on/off operations of the switches S1, S2, and S3, respectively, andFIG. 5Drepresents current flowing through the inductors L1, L2, and L3. When the switches S1, S2, and S3are turned on/off according to the control signals shown inFIGS. 5A-5C, the inductors L1, L2, and L3may show current characteristics shown inFIG. 5D. Due to the current characteristics of the inductors L1, L2, and L3as shown inFIG. 5D, the converter304may boost an input voltage.

FIG. 6is a graph showing a relation of efficiency to power of the converter shown inFIG. 4.

It has been described above with reference toFIG. 4that the first group of the inductor L1, the diode D1, and the switch S1, the second group of the inductor L2, the diode D2, and the switch S2, and the third group of the inductor L3, the diode D3, and the switch S3are involved in boosting. That is, the three groups connected in parallel to each other may be involved in boosting. By selectively operating some or all of the three groups connected in parallel to each other according to desired power, it is possible to operate the converter304with high efficiency from low output power to high output power. Since the converter304ofFIG. 4corresponds to a three-parallel structure, one-parallel to three-parallel structures can be implemented by selectively turning on/off the switches S1, S2, and S3.

FIG. 7shows a second embodiment of a charging apparatus of an electric vehicle according to the present disclosure.

A basic configuration and operation of a converter304shown inFIG. 7are the same as those of the converter304ofFIG. 4as described above. Like the converter304ofFIG. 4, the converter304ofFIG. 7may boost a DC voltage of 400V supplied from the second rapid charger354outside the electric vehicle100to 800V so as to charge the high-voltage battery102.

However, the converter304ofFIG. 7may further include a rapid charging switch702as switching means at the input side. The rapid charging switch702may be configured with three relays R1, R2, and R3. The rapid charging switch702may enable the high-voltage battery102to be charged, regardless of which one of the first rapid charger352and the second rapid charger354is connected to the electric vehicle100.

For example, when the second rapid charger354is connected to the converter304, the second relay R2and the third relay R3of the rapid charging switch702may be turned on, the first relay R1of the rapid charging switch702may be turned off, and the converter304may operate. In this case, the converter304ofFIG. 7may operate in the same manner as the converter304ofFIG. 4as described above to charge the high-voltage battery102.

When the first rapid charger352is connected to the converter304, the second relay R2and the third relay R3of the rapid charging switch702may be turned off, the first relay R1of the rapid charging switch702may be turned on, and the converter304may not operate. In this case, charging current may flow to the high-voltage battery102through the first relay R1. In the converter304ofFIG. 4, current may flow through the inductors L1, L2, and L3and the diodes D1, D2, and D3, whereas in the converter304ofFIG. 7, current may flow to the high-voltage battery102directly through the first relay R1that is turned on. Accordingly, the converter304ofFIG. 7can obtain higher efficiency than the converter304ofFIG. 4(due to a smaller number of resistor elements).

The relays R1, R2, and R3shown inFIG. 7may be selectively turned on and off when the vehicle100is in a charging mode to be involved in charging the high-voltage battery102, and when the vehicle100is in a driving mode, all of the relays R1, R2, and R3may be turned off.

FIG. 8shows a third embodiment of a charging apparatus of an electric vehicle according to the present disclosure.

A basic configuration and operation of a converter304shown inFIG. 8are the same as those of the converter304ofFIG. 7as described above. Like the converter304ofFIG. 7, the converter304ofFIG. 8may boost a DC voltage of 400V supplied from the second rapid charger354outside the electric vehicle100to 800V so as to charge the high-voltage battery102, wherein a rapid charging switch802provided at an input side of the converter304enables the high-voltage battery102to be charged, regardless of which one of the first rapid charger352and the second rapid charger354is connected to the electric vehicle100.

The rapid charging switch802provided in the converter304ofFIG. 8may be configured with a diode D4, a second relay R2, and a third relay R3. Compared to the rapid charging switch702ofFIG. 7, the rapid charging switch802may include the diode D4, instead of the first relay R1.

When the second rapid charger354is connected to the converter304, the second relay R2and the third relay R3of the rapid charging switch802may be turned on, and then the converter304may operate. In this case, the converter304ofFIG. 8may operate in the same manner as the converter304ofFIG. 4described above to charge the high-voltage battery102.

Meanwhile, when the first rapid charger352is connected to the converter304, the second relay R2and the third relay R3of the rapid charging switch802may be turned off, and the converter304may not operate. In this case, charging current may flow to the high-voltage battery102through the diode D4. In the converter304ofFIG. 4, current may flow through the inductors L1, L2, and L3and the diodes D1, D2, and D3, whereas in the converter304ofFIG. 8, current may flow to the high-voltage battery102directly through the first relay R1that is turned on. Accordingly, the converter304ofFIG. 8can obtain higher efficiency than the converter304ofFIG. 4(due to a smaller number of resistor elements).

Particularly, since the converter304ofFIG. 8uses the diode D4instead of the first relay R1, it is unnecessary to control the first relay R1, resulting in simplification of control logics.

FIG. 9is a block diagram of another type of a charging apparatus of an electric vehicle according to an embodiment of the present disclosure.

The charging apparatus shown inFIG. 9may have characteristics that are different from those of the charging apparatus shown inFIG. 3, as follows. That is, the charging apparatus ofFIG. 3may boost a DC voltage of 400V provided from the second rapid charger354through the separate converter304so as to charge the high-voltage battery102. In contrast, the charging apparatus ofFIG. 9may boost a DC voltage of 400V to 800V by using the motor212and the inverter206installed in the electric vehicle100as a converter, without including the converter304.

As shown inFIG. 9, if the motor212and the inverter206are used as if they are a converter, the motor212may operate as an inductor, and the inverter206may operate as a diode and a switch. A DC voltage of 400V provided from the second rapid charger354may be provided to the inverter206and the motor212. In this case, a neutral terminal of the motor212may be connected to the second rapid charger354. Through a structure of the second rapid charger354, the motor212, and the inverter206, as shown inFIG. 9, a DC voltage of 400V provided from the second rapid charger354may be boosted to a DC voltage of 800V, and the DC voltage of 800V may be used to charge the high-voltage battery102.

Since the charging apparatus shown inFIG. 9requires no converter, the charging apparatus can have a simple structure, and accordingly, a manufacturing cost can be reduced.

Charging by the slow charger356and charging by the first rapid charger352may be performed in the same manner as the embodiment ofFIG. 3described above. That is, commercial AC power provided from the slow charger356may be converted and boosted to a DC voltage of 800V by the on-board charger302, and then used to charge the high-voltage battery102. A DC voltage of 800V supplied from the first rapid charger352may be supplied as it is to the high-voltage battery102. Since the high-voltage battery102has a charging voltage of 500V to 800V, a DC voltage of 800V supplied from the first rapid charger352can charge the high-voltage battery102without having to be boosted.

FIG. 10shows a fourth embodiment of a charging apparatus of an electric vehicle according to the present disclosure. The motor212and the inverter206ofFIG. 10may operate as the converter304to boost a DC voltage of 400V provided from the second rapid charger354outside the electric vehicle100to 800V so as to charge the high-voltage battery102.

InFIG. 10, inductors L1, L2, and L3may be coils of the motor212. InFIG. 10, switches S1, S2, S3, S4, S5, and S6may be components of the inverter206. A combination of the inductors L1, L2, and L3of the motor212and the switches S1, S2, S3, S4, S5, and S6of the inverter206may constitute a boost circuit to boost an input voltage of 400V to generate an output voltage of 800V. The inverter L1and the switches S1and S4may form a group to boost an input voltage. The inverter L2and the switches S2and S5may form another group, and the inverter L3and the switches S3and S6may form another group to operate in the same manner as the group of the inverter L1and the switches S1and S4. A pair of the switches S1, S2, and S3and a pair of the switches S4, S5, and S6may be turned on/off alternately. The switching operation will be described in detail with reference toFIGS. 11A-11D, below.

FIGS. 11A-11Dare graphs showing electrical characteristics of the motor and the inverter according to an embodiment of the present disclosure.

FIGS. 11A-11Drepresent control signals for controlling on/off operations of the switches S1, S2, S3, S4, S5, and S6, andFIG. 11Drepresents current flowing through the inductors L1, L2, and L3. If the switches S1, S2, S3, S4, S5, and S6are turned on/off according to the control signals as shown inFIGS. 11A-11D, the inductors L1, L2, and L3may show current characteristics as shown inFIG. 11D. Due to the current characteristics of the inductors L1, L2, and L3as shown inFIG. 11D, an input voltage may be boosted.

FIG. 12is a block diagram of another type of a charging apparatus of an electric vehicle according to an embodiment of the present disclosure.

The charging apparatus shown inFIG. 12may have characteristics which are different from those of the charging apparatus shown inFIG. 9, as follows. The charging apparatus ofFIG. 9may use no rapid charging switch, whereas the charging apparatus ofFIG. 12may use a rapid charging switch1202.

The rapid charging switch1202ofFIG. 12may operate in the same manner as the rapid charging switch702ofFIG. 7or the rapid charging switch802ofFIG. 8. However, unlike the embodiments ofFIG. 7 or 8, the rapid charging switch1202may be provided as a separate component outside the inverter206.

If the rapid charging switch1202is added as shown inFIG. 12, the electric vehicle100can obtain the same operation and effect as in the embodiments ofFIGS. 7 and 8, even when the motor212and the inverter206installed in the electric vehicle100are used as if they are a converter.

FIG. 13shows a fifth embodiment of a charging apparatus of an electric vehicle according to the present disclosure. The motor212and the inverter206ofFIG. 13may operate as the converter304to boost a DC voltage of 400V provided from the second rapid charger354outside the electric vehicle100to 800V so as to charge the high-voltage battery102.

InFIG. 13, inductors L1, L2, and L3may be coils of the motor212. InFIG. 13, switches S1, S2, S3, S4, S5, and S6may be components of the inverter206. A combination of the inverters L1, L2, and L3of the motor212and the switches S1, S2, S3, S4, S5, and S6of the inverter206may constitute a boost circuit to boost an input voltage of 400V to generate an output voltage of 800V.

A rapid charging switch1302may be configured with three relays R1, R2, and R3. The rapid charging switch1302may enable the high-voltage battery102to be charged, regardless of which one of the first rapid charger352and the second rapid charger354is connected to the electric vehicle100.

For example, when the second rapid charger354is connected to the rapid charging switch1302, the second relay R2and the third relay R3of the rapid charging switch1302may be turned on, the first relay R1of the rapid charging switch1302may be turned off, and the motor212and the inverter206may operate. In this case, the motor212and the inverter206ofFIG. 13may operate in the same manner as the converter304ofFIG. 4as described above to charge the high-voltage battery102.

When the first rapid charger352is connected to the rapid charging switch1302, the second relay R2and the third relay R3of the rapid charging switch1302may be turned off, the first relay R1of the rapid charging switch1302may be turned on, and the motor212and the inverter206may not operate. In this case, charging current may flow to the high-voltage battery102through the first relay R1. In the embodiment ofFIG. 10, current may flow through the inductors L1, L2, and L3and the diodes D1, D2, D3, D4, D5, and D6, whereas in the embodiment ofFIG. 13, current may flow directly to the high-voltage battery102through the first relay R1that is turned on. Accordingly, the embodiment ofFIG. 13can obtain higher efficiency than the embodiment ofFIG. 10(due to a smaller number of resistor elements).

The relays R1, R2, and R3shown inFIG. 13may be selectively turned on and off when the vehicle100is in a charging mode to be involved in charging the high-voltage battery102, and when the vehicle100is in a driving mode, all of the relays R1, R2, and R3may be turned off.

FIG. 14shows a sixth embodiment of a charging apparatus of an electric vehicle according to the present disclosure.

A basic configuration and operation of the embodiment shown inFIG. 14are the same as those of the embodiment ofFIG. 4as described above. Like the embodiment ofFIG. 13, a DC voltage of 400V supplied from the second rapid charger354outside the electric vehicle100may be booted to 800V so as to charge the high-voltage battery102, wherein a rapid charging switch1402enables the high-voltage battery102to be charged, regardless of which one of the first rapid charger352and the second rapid charger354is connected to the electric vehicle100.

The rapid charging switch1402ofFIG. 14may be configured with a diode D4, a second relay R3, and a third relay R3. Compared to the rapid charging switch1302ofFIG. 13, the rapid charging switch1402ofFIG. 14may include the diode D4, instead of the first relay R1.

When the second rapid charger354is connected to the rapid charging switch1402, the second relay R2and the third relay R3of the rapid charging switch1402may be turned on, and then, the motor212and the inverter206may operate. In this case, the motor212and the inverter206ofFIG. 14may operate in the same manner as the embodiment ofFIG. 10as described above to charge the high-voltage battery102.

When the first rapid charger352is connected to the rapid charging switch1402, the second relay R2and the third relay R3of the rapid charging switch1402may be turned off, and then, the motor212and the inverter206may not operate. In this case, the charging current may flow to the high-voltage battery102through the diode D4. In the embodiment ofFIG. 10, the current may flow through the inductors L1, L2, and L3and the diodes D1, D2, and D3, whereas in the inverter206ofFIG. 14, current may flow directly to the high-voltage battery102through the first relay R1that is turned on. Accordingly, the inverter206ofFIG. 14can obtain higher efficiency than the inverter206ofFIG. 10(due to a smaller number of resistor elements).

Particularly, since the rapid charging switch1402ofFIG. 14uses the diode D4instead of the first relay R1, it is unnecessary to control the first relay R1, resulting in simplification of control logics.

The relays R1, R2, and R3shown inFIG. 13may be selectively turned on and off when the vehicle100is in a charging mode to be involved in charging the high-voltage battery102, and when the vehicle100is in a driving mode, all of the relays R1, R2, and R3may be turned off.

FIG. 15is a block diagram of another type of a charging apparatus of an electric vehicle according to an embodiment of the present disclosure.

The charging apparatus shown inFIG. 15may have characteristics which are different from those of the charging apparatus shown inFIG. 12, as follows. That is, the charging apparatus ofFIG. 15may add an external inductor L4between a rapid charging switch1502and the motor212. The external inductor L4may be different from the inductors L1, L2, and L3of the motor212.

The rapid charging switch1502ofFIG. 15may operate in the same manner as the rapid charging switch1202ofFIG. 12as described above. However, ripples of current flowing to the rapid charging switch1502may be reduced by the external inductor L4added between the rapid charging switch1502and the motor212.

FIG. 16shows a seventh embodiment of a charging apparatus of an electric vehicle according to the present disclosure. The motor212and the inverter206ofFIG. 16may operate as the converter304to boost a DC voltage of 400V provided from the second rapid charger354to 800V so as to charge the high-voltage battery102.

InFIG. 16, inductors L1, L2, and L3may be coils of the motor212. InFIG. 16, switches S1, S2, S3, S4, S5, and S6may be components of the inverter206. A combination of the inductors L1, L2, and L3of the motor212and the switches S1, S2, S3, S4, S5, and S6of the inverter206may constitute a boost circuit to boost an input voltage of 400V to generate an output voltage of 800V.

The rapid charging switch1502may be configured with three relays R1, R2, and R3. The rapid charging switch1502may enable the high-voltage battery102to be charged, regardless of which one of the first rapid charger352and the second rapid charger354is connected to the electric vehicle100. The rapid charging switch1502may include the two relays R2and R3and the single diode D4, instead of the three relays R1, R2, and R3.

The relays R1, R2, and R3shown inFIG. 16may be selectively turned on and off when the vehicle100is in a charging mode to be involved in charging the high-voltage battery102, and when the vehicle100is in a driving mode, all of the relays R1, R2, and R3may be turned off.

The external inductor L4may be connected between the second relay R2and a neutral terminal of the motor211. Operation of the external inductor L4is shown inFIG. 17.

FIG. 17is a graph for describing operation of the external inductor L4shown inFIG. 16.

It can be seen fromFIG. 17that ripples of switch current of when the external inductor L4exists are relatively smaller than those of switch current of when no external inductor L4exists.

If the external inductor L4is added, the external inductor L4may be connected in series to the inductors L1, L2, and L3of the motor212to increase total inductance. Accordingly, ripples (peak to peak) of current flowing to the switches S1, S2, S3, S4, S5, and S6may be reduced. Reduction of ripples by the external inductor L4may reduce conduction loss due to a reduction of Root Mean Square (RMS) current, as well as on/off switching loss of the switches S1, S2, S3, S4, S5, and S6, resulting in an improvement of power conversion efficiency and a reduction of heating of the switches S1, S2, S3, S4, S5, and S6.

FIG. 18is a block diagram of another type of a charging apparatus of an electric vehicle according to an embodiment of the present disclosure.

The charging apparatus shown inFIG. 18may have characteristics that are different from those of the charging apparatus shown inFIG. 12, as follows. That is, the charging apparatus ofFIG. 12may include the rapid charging switch1202outside the inverter206, whereas the charging apparatus ofFIG. 18may include a rapid charging switch1802inside an inverter1806.

The rapid charging switch1802ofFIG. 18may operate in the same manner as the rapid charging switch1202ofFIG. 12as described above. However, unlike the embodiment ofFIG. 12, since the rapid charging switch1802according to the embodiment ofFIG. 18is disposed inside the inverter1806, the inverter1806and the rapid charging switch1802can be implemented as a single integrated module so that switching of the rapid charging switch1802and the inverter1806can be controlled by one controller (simplification of control logics).

According to an aspect of the present disclosure, by providing a converter for converting power between a charger installed in a charging facility and a battery of an electric vehicle, it is possible to achieve the compatibility between a rapid charger and a high-voltage battery.