阅读说明：本技术 用于电动车辆的dc-dc转换器 (DC-DC converter for electric vehicle ) 是由 朴哲佑 金佑燮 于 2019-12-30 设计创作，主要内容包括：用于电动车辆的DC-DC转换器。提供了一种用于电动车辆的直流-直流(DC-DC)转换器。该DC-DC转换器被配置为用作电动车辆中的谐振转换器或PWM转换器。例如,DC-DC转换器可以作为谐振转换器进行操作,在该谐振转换器中,依次通过第一转换单元、谐振槽、变换单元和第二转换单元施加电流。DC-DC转换器还可以作为脉冲宽度调制PWM转换器进行操作,在该PWM转换器中,依次通过第二转换单元、变换单元和第三转换单元施加电流。(A DC-DC converter for an electric vehicle. A direct current-direct current (DC-DC) converter for an electric vehicle is provided. The DC-DC converter is configured to be used as a resonant converter or a PWM converter in an electric vehicle. For example, the DC-DC converter may operate as a resonant converter in which a current is applied through the first converting unit, the resonant tank, the transforming unit, and the second converting unit in this order. The DC-DC converter may also operate as a pulse width modulation PWM converter in which a current is applied through the second converting unit, the transforming unit, and the third converting unit in this order.)

1. A DC-DC converter, the DC-DC converter comprising:

a first converter;

a resonant tank coupled to the first converter;

a second converter;

a third converter; and

a transducer having a first side coupled to the resonant tank and the third transducer and a second side connected to the second transducer,

wherein, based on inputting a first direct current DC to the DC-DC converter:

the first converter is configured to receive the first DC and convert the received first DC to a first Alternating Current (AC);

the resonant tank is configured to receive the first AC from the first converter and adjust a frequency of the first AC;

the inverter is configured to receive a first AC having an adjusted frequency and convert the first AC into a second AC having a charging voltage for a main battery of an electric vehicle, and output the second AC to the second converter; and is

The second converter is configured to convert the second AC having a charging voltage for the main battery into a second DC for charging the main battery; and is

Wherein based on the third DC input from the main battery:

the second converter is configured to receive the third DC from the main battery and convert the third DC to a third AC;

the converter is configured to receive the third AC and convert the third AC into a fourth AC having a specific voltage, and output the fourth AC to the third converter; and is

The third converter is configured to receive the fourth AC and convert the fourth AC to a fourth DC to be supplied to one or more devices located in the electric vehicle.

2. The converter of claim 1, wherein the transformer comprises:

an insulator having a first insulator side and a second insulator side;

a first inductor and a third inductor provided on the first insulator side of the insulator, the first inductor being connected to the first converter, and the third inductor being connected to the third converter; and

a second inductor provided on the second insulator side of the insulator and connected to the second converter;

wherein, based on the first AC being input through the first inductor, the converter is configured to convert the first AC into a second AC having a charging voltage for the main battery according to a turn ratio between the first inductor and the second inductor,

wherein, based on the third AC being input through the second inductor, the converter is configured to convert the third AC into a fourth AC having the specific voltage according to a turn ratio between the second inductor and the third inductor,

wherein the inductance of the second inductor is determined from the inductance of the first inductor, and

determining an inductance of the third inductor from an inductance of the second inductor.

3. The converter of claim 2, wherein the resonant tank comprises:

an auxiliary inductor having both ends connected to both ends of the first inductor of the converter, respectively; and

at least one switch each disposed between one end of the first inductor and one end of the auxiliary inductor to selectively connect the one end of the auxiliary inductor and the one end of the first inductor,

wherein the at least one switch is each configured to be closed to connect an end of the auxiliary inductor and an end of the first inductor, respectively, based on inputting the first DC to the DC-DC converter, and to be opened to release a connection between the end of the auxiliary inductor and the end of the first inductor, based on not inputting the first DC to the DC-DC converter.

4. The converter of claim 3, wherein the auxiliary inductor of the resonant tank is configured to be connected in parallel with the first inductor based on the at least one switch being closed to produce an inductance that allows the converter to convert the first AC to a second AC having a charging voltage for the main battery, and

wherein an inductance of the first inductor is predetermined to be greater than an inductance of the auxiliary inductor.

5. The converter of claim 1, further comprising:

a switch provided between the first converter and the resonance tank or between the resonance tank and the converter,

wherein the switch is configured to close based on the first DC input being to the DC-DC converter or to open based on the first DC input not being to the DC-DC converter.

6. The converter of claim 3, further comprising:

a Power Factor Correction (PFC) converter configured to convert commercial AC to the first DC, the PFC converter configured to control the at least one switch to close based on converting the commercial AC to the first DC.

7. The converter of claim 5, further comprising:

a Power Factor Correction (PFC) converter configured to convert commercial AC to the first DC, the PFC converter configured to control the switch to close based on converting the commercial AC to the first DC.

8. The converter of claim 3 wherein the DC-DC converter operates as a resonant converter in which the at least one switch is closed and current is applied in sequence through the first converter, the resonant tank, the inverter, and the second converter, and operates as a Pulse Width Modulation (PWM) converter in which the at least one switch is open and current is applied in sequence through the second converter, the inverter, and the third converter.

9. The converter of claim 5 wherein the DC-DC converter operates as a resonant converter in which the switch is closed and current is applied in sequence through the first converter, the resonant tank, the inverter, and the second converter, and operates as a Pulse Width Modulation (PWM) converter in which the switch is open and current is applied in sequence through the second converter, the inverter, and the third converter.

10. A method of operating a DC-DC-DC converter in reverse, the method comprising the steps of:

based on inputting a first direct current DC to the DC-DC converter in a first direction,

converting the first direct current DC to a first alternating current AC using a first converter;

adjusting a frequency of the first AC using a resonant tank;

using a converter to convert the first AC having the adjusted frequency to a second AC; and

using a second converter to convert the second AC to a second DC, an

Based on inputting a third DC to the DC-DC converter in a second direction opposite to the first direction,

converting the third DC to a third AC using the second converter;

using the converter to convert the third AC to a fourth AC; and

converting the fourth AC to a fourth DC using a third converter.

Technical Field

The present disclosure relates to a DC-DC converter used in an electric vehicle.

Background

In general, an electric vehicle may refer to a vehicle that is driven by using electric energy charged from a commercial power supply. An electric vehicle may include a main battery that is charged with electric power from a commercial power supply, and a plurality of vehicle devices that are operated by the main battery.

The current supplied from a commercial power supply for charging an electric vehicle generally has a very high voltage for rapid charging. Therefore, the electric vehicle converts the current of the commercial power source into a charging voltage for the main battery, and inputs the converted charging current into the main battery, so that the main battery is charged. For this purpose, the electric vehicle requires a DC-DC converter that converts an input DC current into a DC current having a different voltage. For example, a resonant converter that converts electric power in a manner of changing frequency is mainly used.

Further, the electric power charged into the main battery may be supplied as a power source for various additional devices provided in the electric vehicle. However, the main battery supplies a voltage of 48V to drive the electric vehicle, and the attachment of the electric vehicle generally uses a current of a voltage level of 12V. Therefore, in order to use the electric power of the main battery as the power source of the attachment, an additional DC-DC converter is required. Also, in such a case that the conversion of the voltage level is not performed in a large range, a Pulse Width Modulation (PWM) converter of a PWM method that converts a current according to a time at which power is transmitted at a fixed frequency is mainly used.

Normally, the DC current cannot be converted. Therefore, the DC-DC converter has the following configuration: to perform the conversion, an input direct current (first DC)100 is converted into an Alternating Current (AC), the AC current is converted, and the converted AC current is converted into a DC current again. Therefore, as illustrated in fig. 1, in general, a DC-DC converter may include: a first current converting unit 110, the first current converting unit 110 converting an input DC current (first DC)100 into an AC current; a transforming unit 120, the transforming unit 120 transforming the AC current transformed in the first current transforming unit 110 into an AC current of another voltage level; and a second current converting unit 130, the second current converting unit 130 converting the AC current converted in the converting unit 120 into a DC current (second DC)150 again.

Since the converter is configured and used to convert electric power in different ways according to the range of voltage to be converted as described above, electric vehicles generally use a resonance converter and a PWM converter that are respectively connected to a main battery. Therefore, the resonant converter and the PWM converter require their own installation space in the interior device of the electric vehicle, which makes it difficult to efficiently utilize the interior space of the electric vehicle.

Disclosure of Invention

An aspect of the present disclosure provides a DC-DC converter that can employ both resonance type power conversion and PWM type power conversion.

Another aspect of the present disclosure provides a DC-DC converter capable of functioning as a resonant converter while a main battery is being charged and as a PWM converter while the main battery is being discharged by changing an inductance characteristic.

To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, there is provided a DC-DC converter including: a first conversion unit configured to receive direct current converted from commercial alternating current and convert the received direct current into alternating current; a resonant tank having a resonant inductor and a capacitor and configured to convert a frequency of a current input from the first conversion unit; a second conversion unit configured to convert an alternating current having a charging voltage for a main battery of an electric vehicle into a direct current for charging the main battery when the alternating current is input, or convert the direct current into the alternating current when the direct current is input from the main battery; a third conversion unit configured to receive alternating current converted into current having a specific voltage and convert the received alternating current into direct current to be supplied to a device provided in the electric vehicle; and a conversion unit having one side connected to the resonance tank and the third conversion unit and the other side connected to the second conversion unit, and configured to convert the alternating current having the converted frequency into an alternating current having a charging voltage for the main battery when the alternating current having the converted frequency is input, so as to output the converted alternating current to the second conversion unit, and convert the alternating current converted in the second conversion unit into an alternating current having the specific voltage, so as to output the converted alternating current to the third conversion unit when the alternating current converted in the second conversion unit is input.

In an embodiment, the transformation unit comprises: an insulator; a first inductor and a third inductor provided at one side of the insulator, the first inductor being connected to the first converter unit, and the third inductor being connected to the third converter; and a second inductor disposed at the other side of the insulator and connected to the second conversion unit, wherein when the alternating current converted in the first conversion unit is input through the first inductor, the conversion unit converts the input alternating current into an alternating current having a charging voltage for the main battery according to a turn ratio between the first inductor and the second inductor, and wherein when the alternating current converted in the second conversion unit is input through the second inductor, the conversion unit converts the input alternating current into an alternating current having the specific voltage according to a turn ratio between the second inductor and the third inductor.

In an embodiment, the inductance of the second inductor is determined from the inductance of the first inductor and the inductance of the third inductor is determined from the inductance of the second inductor.

In an embodiment, the third inductor is configured wherein a plurality of inductors are connected in series.

In an embodiment, the resonance tank includes: a resonant inductor; an auxiliary inductor having both ends connected to both ends of the first inductor of the transforming unit, respectively; and at least one switch provided between at least one of both ends of the first inductor and at least one of both ends of the auxiliary inductor to connect at least one end of the auxiliary inductor and at least one end of the first inductor, wherein when a direct current converted from a commercial alternating current is input to the direct current-direct current converter, the at least one switch is closed such that at least one end of the auxiliary inductor and at least one end of the first inductor are connected, and when a direct current converted from the commercial alternating current is not input to the direct current-direct current converter, the at least one switch is opened such that a connection between at least one end of the auxiliary inductor and at least one end of the first inductor is released.

In one embodiment, the resonance tank is configured such that the auxiliary inductor and the first inductor are connected in parallel with each other according to whether the at least one switch is closed, to generate an inductance that allows the conversion unit to convert the alternating current converted in the first conversion unit into an alternating current having a charging voltage for the main battery.

In an embodiment, the inductance of the first inductor is a predetermined magnitude greater than the inductance of the auxiliary inductor.

In one embodiment, the DC-DC converter further includes a switch provided between the first conversion unit and the resonance tank or between the resonance tank and the conversion unit, wherein when the direct current converted from the commercial alternating current is input to the DC-DC converter, the switch is closed such that both ends of the switch are connected to each other, and when the direct current converted from the commercial alternating current is not input to the DC-DC converter, the switch is opened and both ends of the switch are disconnected from each other.

In an embodiment, the DC-DC converter further includes a Power Factor Correction (PFC) conversion unit configured to convert commercial alternating current into direct current, wherein the PFC conversion unit controls the switch to be closed when commercial alternating current is converted into the direct current.

In an embodiment, the DC-DC converter operates as a resonant converter in which a current is applied sequentially through the first converting unit, the resonant tank, the converting unit, and the second converting unit when the switch is closed, and operates as a Pulse Width Modulation (PWM) converter in which a current is applied sequentially through the second converting unit, the converting unit, and the third converting unit when the switch is open.

Systems, devices, methods, and techniques according to embodiments of the present disclosure can provide a number of advantages.

For example, according to at least one embodiment of the present disclosure, the electric vehicle can use one DC-DC converter as a resonant converter or a PWM converter, thereby more efficiently utilizing the space inside the electric vehicle.

In addition, some embodiments of the present disclosure satisfy inductance characteristics required to charge and discharge the main battery, so that one DC-DC converter can provide both the function of the resonant converter and the function of the PWM converter.

In addition, some embodiments of the present disclosure efficiently block the inflow of a reflected voltage that may occur during the discharge of the main battery, thereby preventing a leakage current generated when the DC-DC converter operates as a PWM converter and preventing element burning due to voltage stress or current stress.

Drawings

Fig. 1 is a block diagram illustrating a typical structure of a DC-DC converter.

Fig. 2 is a block diagram and a circuit diagram illustrating a structure of a DC-DC converter according to an embodiment of the present disclosure.

Fig. 3 is a conceptual diagram illustrating current flow during charging and discharging of a main battery in a DC-DC converter according to an embodiment of the present disclosure.

Fig. 4 is a block diagram illustrating a structure of a DC-DC converter having a switch according to an embodiment of the present disclosure.

Fig. 5 is a diagram illustrating two examples of switches provided in a resonance tank among examples of a DC-DC converter including a switch according to an embodiment of the present disclosure.

Fig. 6 is a block diagram illustrating an example DC-DC converter according to an embodiment of the present disclosure, in contrast to a typical example circuit including both a resonant converter and a PWM converter.

Detailed Description

A description will now be given in detail according to embodiments disclosed herein with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or similar reference numerals will be provided for the same or equivalent components, and the description thereof will not be repeated. In general, suffixes such as "module" and "unit" may be used to refer to an element or component. Such suffixes are used herein merely to facilitate the description of the specification and are not intended to impart any particular meaning or function to the suffix itself. In describing the present disclosure, a detailed description of related known functions or configurations may be omitted for the sake of brevity, but will be understood by those skilled in the art. The drawings are used to help easily understand the technical concepts of the present disclosure, and it should be understood that the concepts of the present disclosure are not limited by the drawings. The concepts of the present disclosure should be understood to extend to any modifications, equivalents, and alternatives other than the drawings.

Fig. 2 is a block diagram (a) and a circuit diagram (b) illustrating an example structure of a DC-DC converter according to an embodiment of the present disclosure.

Referring to block diagram (a) of fig. 2, the DC-DC converter according to an embodiment of the present disclosure may include a first current conversion unit 210, a resonance tank 220, a transformation unit 230, a second current conversion unit 240, a main battery 250, and a third current conversion unit 260.

The first current converting unit 210 may be configured to receive a DC current and convert the input DC current into an AC current for conversion. In some implementations, the DC current may be a DC current input for charging the main battery. For example, the DC current input to the first current converting unit 210 may be a DC current into which an AC current supplied from a commercial power supply has been converted by Power Factor Correction (PFC). In some implementations, the DC current input to the first current converting unit 210 may be a current according to a voltage of a commercial power source, and may be a current having a voltage of about 400V.

After converting the DC current into an AC current having a certain frequency in the first current converting unit 210, the converted AC current may be input to the resonance tank 220. The resonance tank 220 may include a resonance circuit having a resonance inductor and a capacitor, and may convert a frequency of the AC current input from the first current converting unit 210 according to a resonance frequency of the resonance circuit. Then, the AC current having the converted frequency may be supplied to the transforming unit 230.

The transformation unit 230 may be connected to the resonance tank 220, and may transform an AC current applied from the resonance tank 220 into an AC current having a different voltage. For example, the transformation unit 230 may transform the AC current supplied from the resonance tank 220 into an AC current of a charging voltage (e.g., a voltage corresponding to 48V) for the main battery 250. Then, the converted AC current may be output to the second current converting unit 240.

When the AC current converted by the conversion unit 230 is input to the second current conversion unit 240, the second current conversion unit 240 may convert the input AC current into a DC current. In an embodiment where the input AC current has a charging voltage for the main battery 250, the current conversion unit 240 may generate a DC current of the charging voltage capable of charging the main battery 250. The generated DC current may be supplied to the main battery 250 to charge the main battery 250.

In some implementations, the second current conversion unit 240 may operate to receive a DC current from the main battery 250 when the electric power charged into the main battery 250 is discharged. For example, the second current conversion unit 240 may receive a DC current of 48V equal to an operating voltage of the main battery 250. As such, when a current is input from the main battery 250, the second current conversion unit 240 may convert the input DC current into an AC current of 48V and output the converted current to the conversion unit 230.

In some implementations, the transforming unit 230 may operate to transform the input AC current into a current according to an operating voltage of the auxiliary battery to supply or charge power to an additional device or various additional devices provided in the electric vehicle. For example, when the operating voltage of the accessory device and the auxiliary battery is 12V, the transforming unit 230 may operate to transform the 48V AC current into the 12V AC current and output the transformed AC current to the third current converting unit 260.

In some implementations, the third current conversion unit 260 may be connected to an auxiliary battery to supply or charge power to an additional device or various additional devices provided in the electric vehicle. When an AC current having an operation voltage of the auxiliary battery and the additional device is applied, the third current converting unit 260 may operate to convert the AC current into a DC current. The converted DC current may be supplied to a connected accessory device or auxiliary battery. In the illustrated example, the auxiliary battery 270 is illustrated as being connected to the third current converting unit 260.

As described herein, the transformation unit 230 of the DC-DC converter according to the embodiment of the present disclosure may be connected to both the resonance tank 220 and the third current conversion unit 260, and also connected to the second current conversion unit 240. When a current is input from any one side, the transformation unit 230 may convert the input current into a current having a different voltage according to electromagnetic induction and output the converted current. That is, when a current is applied from the resonant tank 220, the conversion unit 230 of the DC-DC converter according to the embodiment may be configured to convert the input current and output the converted current to the second current conversion unit 240. On the other hand, when a current is applied from the second current converting unit 240, the transforming unit 230 may be configured to output the applied current to the third current converting unit 260.

Therefore, when commercial power converted into DC current by the PFC converter is applied, the first current conversion unit 210, the resonance tank 220, the conversion unit 230, and the second current conversion unit 240 may be connected (280) in the DC-DC converter so as to change the frequency of the current of the commercial power, convert the voltage of the current having the changed frequency, and supply the current having the converted voltage as charging power to the main battery 250. That is, when commercial power is applied, the DC-DC converter may operate as a resonant converter.

On the other hand, when power is applied from the main battery 250, the second current conversion unit 240, the transformation unit 230, and the third current conversion unit 260 may be connected (290) in the DC-DC converter so as to transform the current supplied from the main battery 250 and supply the transformed current to the auxiliary battery 270. That is, when power is applied from the main battery 250, the DC-DC converter may operate as a PWM converter.

Fig. 2 (b) illustrates an example circuit structure of the resonant tank 220 and the transforming unit 230 in the DC-DC converter according to the embodiment of the present disclosure.

Referring to diagram (b) of fig. 2, the transforming unit 230 may be provided at one side of the insulator 231 with a first inductor 232 connected to the resonance tank 220 and a third inductor connected to the third current converting unit 260 and at the other side of the insulator 231 with a second inductor 233 connected to the second current converting unit 240. For example, the third inductor may be configured by connecting multiple inductors 234, 235 in series.

In some implementations, the resonant tank 220 can include a resonant inductor 221 and a capacitor 222. In addition, the first inductor 232 of the transforming unit 230 may include an auxiliary inductor 225 such that both ends of the auxiliary inductor 225 are connected to both ends of the first inductor 232, respectively. That is, the first inductor 232 and the auxiliary inductor 225 may be connected in parallel to each other, and thus, an inductance value required for the resonant converter may be generated according to the parallel connection of the first inductor 232 and the auxiliary inductor 225, as shown in the following equation 1.

[ formula 1]

Here, L1 denotes the inductance of the first inductor, L e denotes the inductance of the auxiliary inductor, and L1 | | L e denotes the inductance when L1 is connected in parallel with L e.

In some implementations, depending on the inductance L1 of the first inductor 232, the inductance of the second inductor 233 may be determined from the turn ratio between the side to which current is applied (the first inductor 232) and the side to which current is received (the second inductor 233).

[ formula 2]

Here, L1 denotes the inductance of the first inductor, L2 denotes the inductance of the second inductor, Np denotes the number of turns of the inductor on the side where the current is applied, and Ns denotes the number of turns of the inductor on the side where the current is received.

Therefore, when the inductance (first inductance) of the first inductor 232 is determined, the inductance (second inductance) of the second inductor 233 may be determined. In some implementations of the present disclosure, when the power from the main battery 250 is discharged, the side supplying the current and the side receiving the current may be changed at the transformation unit 230. For example, the side supplying the current may be the second inductor 233 and the side receiving the current may be the third inductors 234, 235. In addition, as shown in equation 2, since the inductance of the side receiving the current is determined according to the inductance of the side supplying the current, when the second inductance of the second inductor 233 is determined, the third inductance of the third inductors 234, 235 may also be determined in a similar manner to equation 2. For example, the third inductance may be larger as the first inductance is larger, because the second inductance may be larger as the first inductance is larger.

In some implementations, unlike operation as a resonant converter, when the main battery 250 is discharged, the transforming unit 230 may operate as a PWM converter transforming the currents supplied by the second and third inductors 233, 234, 235. Therefore, the larger the magnitude of the third inductance, the more efficiently the transformation unit 230 operates. On the other hand, for a resonant converter that converts a current input from commercial power through the first inductor 232 and the second inductor 233, the size of the first inductor 232 may be limited because a specific inductance value is required.

However, as shown in diagram (b) of fig. 2, in an embodiment in which the auxiliary inductor 225 is connected in parallel with the first inductor 232, when the inductance value of the first inductor 232 is sufficiently greater than the inductance value of the auxiliary inductor 225 (i.e., the value of the first inductor 232 has a preset size greater than the value of the auxiliary inductor 225), the inductance value of the parallel-connected inductor (e.g., the inductance value of the auxiliary inductor 225) may be converged to a smaller value.

Therefore, regardless of the size of the first inductor 232, the inductance value of the auxiliary inductor 225 may be the inductance value of the first inductor 232 and the auxiliary inductor 225 connected in parallel. Therefore, when the inductance of the auxiliary inductor 225 is determined according to the inductance value required in the resonant converter, the size of the first inductor 232 can be sufficiently increased.

Fig. 3 shows graphs (a) and (b) for illustrating respective current flows when the main battery 250 is charged and discharged in the DC-DC converter having the resonance tank 220 and the conversion unit 230 according to an embodiment of the present disclosure.

First, diagram (a) of fig. 3 illustrates an example process in which a PFC converts an AC current of a commercial power supply into a DC current and inputs the DC current to a DC-DC converter according to an embodiment of the present disclosure. For example, the input current may be input 300 to the transformation unit 230 through the first current transformation unit 210 and the resonance tank 220, and the current transformed by the transformation unit 230 may be supplied to the main battery 250 through the second current transformation unit 240.

In some implementations, as illustrated in fig. 2, the transformation unit 230 according to an embodiment of the present disclosure may also be connected to a third current conversion unit 260. Accordingly, the reflected current 320 may be supplied to the third current converting unit 260 due to the voltage reflection phenomenon. For example, the reflected current 320 may be converted back to a DC current by the third current converting unit 260, and the converted reflected current 320 may be supplied as a charging current of the auxiliary battery 270. This is because the reflected current is slightly reflected and the voltage thereof is not high according to the characteristics of the conversion unit 230. Therefore, the reflected current may be used as a charging current of the auxiliary battery 270. In addition, since the path in which the reflected current flows is also the path of the output current, there is no problem even when the reflected current is output and is rather usable.

On the other hand, diagram (b) of fig. 3 illustrates an example process in which the current charged into the main battery is input to the DC-DC converter according to an embodiment of the present disclosure. For example, the inputted current may be inputted 350 to the transforming unit 230 through the second current transforming unit 240, and the current transformed by the transforming unit 230 may be supplied 360 to the auxiliary battery 270 through the third current transforming unit 260.

As described above, the transforming unit 230 according to the embodiment of the present disclosure may also be connected to the resonance tank 220. Therefore, the reflected current 320 may also be supplied to the resonance tank 220 due to the voltage reflection phenomenon. For example, a current may be input in a direction opposite to a direction in which power is output from the resonant tank 220, and the input current may be output through the first current converting unit 210.

The first current conversion unit 210 and the resonant tank 220 may form a path for supplying a charging current to the main battery 250. In some cases, current may be output in the opposite direction of the supply current, and the output current may become a leakage current or burn out an element or cause voltage stress or current stress due to the current. In order to control the current supplied in the opposite direction when the power is supplied from the main battery 250, some embodiments of the present disclosure may include at least one switch.

Fig. 4 and 5 illustrate an example in which at least one switch is provided in a DC-DC converter according to an embodiment of the present disclosure.

Fig. 4 illustrates an example in which a switching unit 400 is provided between the first current converting unit 210 and the transforming unit 230. For example, the switching unit 400 may be disposed between the first current conversion unit 210 and the resonance tank 220 (as illustrated in diagram (a) of fig. 4) or between the resonance tank 220 and the transformation unit 230 (as illustrated in diagram (b) of fig. 4). In addition, the switching unit 400 may disconnect the circuit by opening the circuit while supplying power from the main battery 250 to prevent the reflected current supplied from the conversion unit 230 from flowing in.

Alternatively or additionally, the switching unit 400 may be controlled by the PFC. For example, when the PFC converts a commercial AD current into a DC current, the PFC may control the switching unit 400 such that the first current conversion unit 210 and the resonance tank 220 (diagram (a) of fig. 4) or the resonance tank 220 and the conversion unit 230 (diagram (b) of fig. 4) are connected.

On the other hand, when the commercial AD current is not converted into the DC current, the PFC allows the switching unit 400 to be disconnected, whereby the first current conversion unit 210 and the resonance tank 220 (diagram (a) of fig. 4) or the resonance tank 220 and the conversion unit 230 (diagram (b) of fig. 4) may be disconnected. For example, the first current conversion unit 210, the resonance tank 220, and the transformation unit 230 may be connected to each other only while electric power for charging the main battery 250 is being supplied.

In some implementations, at least one switch may be disposed in the resonant tank 220. Fig. 5 illustrates an example in which a switch is provided in the resonance tank.

Diagram (a) of fig. 5 illustrates an example process in which a switch 510 is provided between one end of the auxiliary inductor 225 and one end of the first inductor 232 in order to connect or disconnect the two inductors 225 and 232. For example, when a DC current for charging the main battery 250 is input to the first current conversion unit 210, the switch 510 is closed so that one end of the auxiliary inductor 225 and one end of the first inductor 232 may be connected to each other.

For example, when the switch 510 is closed, the auxiliary inductor 225 and the first inductor 232 may be connected in parallel, and accordingly, power conversion may be performed according to an inductance value when the auxiliary inductor 225 and the first inductor 232 are connected in parallel. That is, the first current converting unit 210, the resonant tank 220, the transforming unit 230 and the second current converting unit 240 may be connected to operate as a resonant converter.

On the other hand, when the DC current is not supplied to the first current converting unit 210, the switch 510 maintains an off state so that the connection between one end of the auxiliary inductor 225 and one end of the first inductor 232 may be disconnected. For example, since the connection between the auxiliary inductor 225 and the first inductor 232 is disconnected, the connection between the transforming unit 230 and the resonant tank 220 may also be disconnected.

Accordingly, when a current is input from the main battery 250 through the second current conversion unit 240, the current may be converted through the third inductors 234 and 235 and the second inductor 233 since the circuit of the first inductor 232 is cut off. The converted current may be output to the third current converting unit 260. Accordingly, the second current converting unit 240, the transforming unit 230 and the third current converting unit 260 are connected so that the DC-DC converter according to the embodiment of the present disclosure may operate as a PWM converter.

In an alternative implementation, as illustrated in diagram (b) of fig. 5, a plurality of switches 510 may be provided at an end of the first inductor and an end of the auxiliary inductor, respectively. For example, the switches 510, 520 may operate in synchronization with each other and may be opened or closed simultaneously.

In addition, the switch 510 or the switches 510, 520 may be controlled by the PFC in the same or similar manner as the switching unit 400. That is, the PFC may control the switch 510 or the switches 510, 520 to be closed when converting the commercial AC current into the DC current. For example, while the electric power that charges the main battery 250 is being supplied, the switch 510 or the switches 510, 520 may be closed to operate as a resonant converter. When operating as a resonant converter as described above, a current may be sequentially applied to the first current converting unit 210, the resonant tank 500, the transforming unit 230, and the second current converting unit 240.

On the other hand, the PFC may control the switch 510 or the switches 510, 520 to be turned off when the commercial AC current is not converted into the DC current. For example, since the circuit of the first inductor 232 of the transforming unit 230 is turned off (e.g., interrupted), the current may be transformed by the third inductors 234 and 235 and the second inductor 233, and the transformed current may be output to the third current converting unit 260. That is, the second current converting unit 240, the transforming unit 230 and the third current converting unit 260 may be connected to operate as a PWM converter. As such, when operating as a PWM converter, current may be sequentially applied to the second current converting unit 240, the transforming unit 230, and the third current converting unit 260.

Fig. 6 is a block diagram illustrating an example process of providing a DC-DC converter according to an embodiment of the present disclosure, in contrast to providing a typical example circuit that includes both a resonant converter and a PWM converter.

Diagram (a) of fig. 6 illustrates an example process in which the main battery 250 includes both a resonant converter and a PWM converter.

Referring to diagram (a) of fig. 6, the resonant converter includes a first DC-AC converting unit 600, a resonant tank 601, a first converting unit 602, and a first AC-DC converting unit 604, and is connected to the main battery 250. In addition, the PWM converter includes a second DC-AC conversion unit 605, a second conversion unit 606, and a second AC-DC conversion unit 607, and is connected to the main battery 250.

In this case, when a commercial AC current is converted into a DC current in the PFC, the converted DC current 200 may be converted into an AC current by the first DC-AC converting unit 600. In addition, the frequency of the current converted in the first DC-AC converting unit 600 may be changed by the resonance tank 601, and the AC current having the changed frequency may be converted into a voltage by the first converting unit 230 to charge the main battery 250. The converted AC current may be input to the first AC-DC conversion unit 604, converted into a DC current, and the converted DC current may be supplied to the main battery 250 to charge the main battery 250.

In addition, the current of the main battery 250 may be converted into an AC current by the second DC-AC conversion unit 605. The converted AC current may be converted into an operating voltage for the auxiliary battery 270 and accessories of the vehicle. And, the converted AC current may be converted into a DC current by the second AC-DC conversion unit 607 and supplied as a power source of the auxiliary battery 270 and the additional devices of the vehicle.

However, as illustrated in diagram (a) of fig. 6, when both the resonant converter and the PWM converter are provided, a plurality of DC-AC converting units and AC-DC converting units are provided and a plurality of converting units are also provided. Therefore, an internal space for mounting the DC-DC converter is required.

In contrast, diagram (b) of fig. 6 illustrates a DC-DC converter in which the main battery 250 is provided to be operable as both a resonant converter and a PWM converter according to an embodiment of the present disclosure.

Referring to diagram (b) of fig. 6, the DC-DC converter according to the embodiment of the present disclosure may be provided with only the first current converting unit 210, the resonant tank 220, the transforming unit 230, the second current converting unit 240, and the third current converting unit 260. Therefore, in the DC-DC converter according to the embodiment of the present disclosure, the number of the conversion units and the current conversion units can be further reduced, and the internal space of the electric vehicle required to mount the DC-DC converter can be reduced. As a result, the interior space of the electric vehicle can be more efficiently utilized.

In addition, a plurality of embodiments have been described herein, but various modifications may be made without departing from the scope of the present disclosure. Accordingly, it will be understood by those skilled in the art to which the present disclosure pertains that various modifications and changes may be made without departing from the essential characteristics of the present disclosure. Therefore, the embodiments disclosed herein are not intended to limit the technical concept of the present disclosure, and the scope of the technical concept of the present disclosure is not limited by these embodiments. The scope of some implementations of the present disclosure is to be construed by the appended claims, and all technical concepts within the equivalent scope should be construed as being included in the scope of the present disclosure.