KR102335226B1 - Selective converter device for electric vehicle obc, and power conversion method of selective converter device for electric vehicle obc - Google Patents

Abstract

Disclosed are a selective converter device for an electric vehicle OBC and a power conversion method of the selective converter device for an electric vehicle OBC. According to an embodiment of the present invention, the selective converter device for an electric vehicle OBC comprises: a first switch for selectively conducting any one of an inductor (L_MPPT) for MPPT control and an inductor (L_PFC) for PFC control by identifying a type of charging mode; and a second switch for selectively applying a pulse width modulation (PWM) pulse corresponding to the type of charging mode to a MOSFET.

Description

Selective converter device for electric vehicle OBC, and power conversion method of selective converter device for electric vehicle OBC

The present invention provides an optional converter for an electric vehicle OBC (On Board Charger) comprising a selective inductor supporting both the PFC (Power Factor Correction) control mode of electric charging and the MPPT (Maximum power point tracking) control mode of solar charging It relates to an apparatus, and a power conversion method of a selective converter device for an electric vehicle OBC.

In particular, the present invention provides a technology of a selective inductor capable of obtaining high power conversion efficiency in both the PFC control mode and the MPPT control mode.

An electric vehicle is a vehicle that operates using electricity as a power source.

The electric vehicle does not use petroleum fuel and an engine, but uses an electric battery and an electric motor to rotate the motor with electricity accumulated in the battery to drive the vehicle. Electricity generated through heat or a chemical reaction, such as a fuel cell or a solar cell, can be utilized for the accumulation of electricity in the battery.

In the accumulation of electricity in the electric vehicle, the PFC (Power Factor Correction) circuit controls a series of processes of accumulating power to the battery inside the electric vehicle through a grid input from the power battery through a charging gun, etc. circuit can be referred to.

Also, in recent years, a photovoltaic (PV) circuit involved in charging a battery of an electric vehicle through solar power generation is also attracting attention.

However, there are many patents and research results on the PFC circuit itself, but there are not many cases of applying the circuit structure and control method that allows the PFC circuit and the PV circuit to be used together.

The power capacity of a typical commercial electric vehicle OBC may be at least 3 kW.

On the other hand, considering the current PV semiconductor manufacturing technology, the cross-sectional area of the PV semiconductor that can be attached to the outside of the vehicle, and the PV material, the power capacity of the MPPT control circuit for solar power generation can be up to 500W.

In other words, in the hardware designed for the active and passive elements of the boost converter to match the 3kW power capacity of the electric vehicle OBC, in the mode where the PV output is connected and MPPT control is performed, only the amount of power corresponding to 20% of the load is converted. supplied as output.

In general, since the DC-DC converter is designed to have maximum efficiency only in a specific load amount, the efficiency may be lowered in the section below the designed load.

That is, the power conversion efficiency of the MPPT control mode, which corresponds to about 20% of the load of 3kW electric vehicle OBC, is inevitably relatively low.

Therefore, while both PFC control for the electric vehicle charger input and MPPT control for the solar panel input are possible, a new technique is urgently required to obtain high power conversion efficiency in the PFC control mode and the MPPT control mode. .

An embodiment of the present invention is a selective converter device for an electric vehicle OBC, which can obtain high power conversion efficiency not only in the PFC control mode but also in the MPPT control mode by optimally selecting the inductor by distinguishing whether it is PFC control or MPPT control , and an object of the present invention is to provide a power conversion method of a selective converter device for an electric vehicle OBC.

In addition, the embodiment of the present invention selects an optimally designed inductor according to each input capacity even when there is an input of PV, which is a renewable energy source, sharing a grid source such as an EV charger. The purpose of this is to maximize the power conversion efficiency.

According to an embodiment of the present invention, a selective converter device for an electric vehicle OBC identifies a type of charging mode, and selectively conducts any one of _{an inductor L MPPT} for MPPT control and an inductor L _{PFC for PFC control.} 1 switch; and a second switch for selectively applying a PWM (Pulse Width Modulation) pulse corresponding to the type of the charging mode to the MOSFET.

In addition, the power conversion method of the selective converter device for an electric vehicle OBC according to an embodiment of the present invention, by identifying the type of charging mode in the first switch, an inductor L _MPPT for MPPT control, and an inductor for PFC control selectively conducting any one of the L _PFCs; and in the second switch, selectively applying a PWM pulse corresponding to the type of the charging mode to the MOSFET.

According to an embodiment of the present invention, by optimally selecting an inductor by distinguishing whether it is PFC control or MPPT control, high power conversion efficiency can be obtained not only in PFC control mode but also in MPPT control mode, selective type for electric vehicle OBC It is possible to provide a converter device and a method for converting power of a selective converter device for an electric vehicle OBC.

In addition, according to the present invention, even when there is an input of PV, which is a renewable energy source, which shares a grid source such as an EV charger, an optimal design inductor is selected according to each input capacity. Power conversion efficiency can be maximized.

1 is a block diagram showing the configuration of a selective converter device for an electric vehicle OBC according to an embodiment of the present invention.
FIG. 2 is a graph showing the efficiency of general power conversion according to a load factor when an electric vehicle OBC operates as a PFC control.
3 is a view for explaining an inductor-selective DC-DC converter according to the OBC (PFC) mode and the PV (MPPT) mode of the present invention.
4 is a diagram illustrating an inductor selection configuration in a solar cell charging mode and a grid charging mode according to an embodiment of the present invention.
5 is a flowchart illustrating a power conversion method of a selective converter device for an electric vehicle OBC according to an embodiment of the present invention.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, since various changes may be made to the embodiments, the scope of the patent application is not limited or limited by these embodiments. It should be understood that all modifications, equivalents and substitutes for the embodiments are included in the scope of the rights.

The terms used in the examples are used for the purpose of description only, and should not be construed as limiting. The singular expression includes the plural expression unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiment belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

In addition, in the description with reference to the accompanying drawings, the same components are given the same reference numerals regardless of the reference numerals, and the overlapping description thereof will be omitted. In describing the embodiment, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the embodiment, the detailed description thereof will be omitted.

1 is a block diagram showing the configuration of a selective converter device for an electric vehicle OBC according to an embodiment of the present invention.

Referring to FIG. 1 , a selective converter device 100 for an electric vehicle OBC (hereinafter abbreviated as 'selective converter device') according to an embodiment of the present invention includes a first switch 110 and a second switch It can be configured to include (120).

First, the first switch 110 selectively conducts any one of _{an inductor L MPPT} for MPPT control and an inductor L _{PFC for PFC control by identifying the type of charging mode.} That is, the first switch 110 may check the type of mode in which the electric vehicle is charged, and may serve to determine an inductor for optimal charging according to the checked mode.

_{Basically, the first switch 110 selects and conducts the inductor L PFC} for PFC control when the electric vehicle is charging electricity, and only when the electric vehicle is charged by solar power, MPPT control It can be conducted by selecting the inductor L for _MPPT.

According to an embodiment, when the solar power (PV) is input from the solar cell, the first switch 110 may identify the charging mode as the solar cell charging mode and select the _{inductor L MPPT for controlling the MPPT.} That is, the first switch 110 may select and conduct the _{inductor L MPPT} on the premise that photovoltaic power generation is being performed during the usual daytime when the sun is shining.

Also, when a grid is input from the power battery, the first switch 110 may identify the charging mode as the grid charging mode and select the _{inductor L PFC for controlling the PFC.} That is, the first switch 110 may select and conduct the _{inductor L PFC} while the charging gun is inserted into the charging port of the electric vehicle and electric charging is performed from the power battery of the charging station. If the charging gun insertion is released, the first switch 110 may be changed from the inductor L _{PFC to the inductor L MPPT} and reselected to conduct.

In another embodiment, when an input signal from the outside is input without going through a rectifier located at the tip, the first switch 110 may identify the charging mode as the solar cell charging mode. That is, the first switch 110 may select and conduct the _{inductor L MPPT} when it is determined that the solar power of the DC series output by the solar cell is input as an input signal and processing in the rectifier is unnecessary.

In addition, when the input signal is input via the rectifier, the first switch 110 may identify the charging mode as a grid charging mode. That is, the first switch 110 selects the _{inductor L PFC} by confirming that the AC grid is input as an input signal, and the AC grid is rectified through the rectifier, thereby confirming that electric charging is being performed. so that it can be conducted.

In addition, the second switch 120 selectively applies a PWM (Pulse Width Modulation) pulse corresponding to the type of the charging mode to the MOSFET. That is, the second switch 120 may serve to determine the PWM pulse by the MOSFET according to the type of mode in which the electric vehicle is charged.

As an example, when the inductor L _MPPT is selected by the first switch 110 to conduct, the second switch 120 _{selects a PWM MPPT} pulse for MPPT control and applies it to the MOSFET, thereby generating solar power (PV) The MOSFET for accumulating a circuit is configured in parallel with _{the inductor L MPPT . That is, the second switch 120 selects the PWM MPPT} pulse for MPPT control and applies it to the MOSFET when charging the battery according to the solar power generation, so that the MOSFET and the inductor L _MPPT are configured in parallel to accumulate solar power. let there be

As another example, when the inductor L _PFC is selected and conducted by the first switch 110 , the second switch 120 _{selects a PWM PFC} pulse for PFC control and applies it to the MOSFET. ), a circuit is configured in parallel with _{the inductor L PFC.} That is, the second switch 120 is applied to the MOSFET for PFC control when the battery is charged according to the grid, so that the MOSFET and the inductor L _PFC are configured in parallel to accumulate the grid.

According to an embodiment of the present invention, by optimally selecting an inductor by distinguishing whether it is PFC control or MPPT control, high power conversion efficiency can be obtained not only in PFC control mode but also in MPPT control mode, selective type for electric vehicle OBC It is possible to provide a converter device and a method for converting power of a selective converter device for an electric vehicle OBC.

In addition, according to the present invention, even when there is an input of PV, which is a renewable energy source, which shares a grid source such as an EV charger, an optimal design inductor is selected according to each input capacity. Power conversion efficiency can be maximized.

FIG. 2 is a graph showing the efficiency of general power conversion according to a load factor when an electric vehicle OBC operates as a PFC control.

If the PFC circuit of OBC is directly connected to the PV circuit and used as an MPPT control circuit, the power generated from the PV circuit is 20% of that of the PFC circuit of OBC, so the expected power conversion efficiency is 80~86 on average. % level.

In FIG. 2 , the shaded portion 210 of the graph may be a substantial efficiency section during the MPPT operation of the PV circuit.

As shown in FIG. 2 , the shaded portion 210 has a load factor of 10 to 20% and a power conversion efficiency of about 82 to 87%, which can be referred to as a practical efficiency section during MPPT operation of the PV circuit. have.

In order to maximize the relatively low power conversion efficiency in the MPPT mode of the PV circuit, an inductor selection type circuit configuration for each mode is proposed.

When operating as PFC control of OBC circuit or MPPT control of PV circuit, the factor that has the greatest influence on power conversion efficiency is the inductor.

The peak value and average value of the inductor current when operating under the PFC control of the OBC circuit or the MPPT control of the PV circuit may be determined according to the inductance value of the inductor. These current values have a great influence on the amount of power lost through conduction of other devices (eg, FETs, diodes, and caps).

In particular, when the PFC control of the OBC circuit or the MPPT control of the PV circuit is operated, the difference in power conversion efficiency for each mode according to the inductance value of the inductor is inevitably different because the power capacity differs by up to 8~90%. .

3 is a view for explaining an inductor selection type DC-DC converter according to the OBC (PFC) mode and the PV (MPPT) mode of the present invention.

The circuit diagram of FIG. 3 shows an inductor designed to optimize inductance value, magnetic material type, number of turns, etc. according to each mode in OBC (PFC) mode and PV (MPPT) mode to maximize power conversion efficiency. It is a controlled circuit.

As shown in FIG. 3 , the selective converter device 100 includes a first switch 310 and a second switch 320 .

When the solar power (PV) is input from the solar cell, the first switch 310 may identify the charging mode as the solar cell charging mode and select the _{inductor L MPPT for MPPT control.}

In addition, the first switch 310 may select the _{inductor L PFC} for PFC control by identifying the charging mode as the grid charging mode when a grid is input from the power battery.

_{When the inductor L MPPT} is selected and conducted by the first switch 310, the second switch 320 _{selects a PWM MPPT} pulse for MPPT control and applies it to the MOSFET, thereby accumulating solar power (PV). A MOSFET can be circuited in parallel with the _{inductor L MPPT .}

In addition, when the inductor L _PFC is selected by the first switch 310 to conduct, the second switch 320 _{selects a PWM PFC} pulse for PFC control and applies it to the MOSFET, thereby accumulating a grid. A MOSFET can be circuit configured in parallel with the _{inductor L PFC .}

Through this, according to this patent, it is possible to achieve an average power conversion efficiency of 95% or more in both the OBC (PFC) mode and the PV (MPPT) mode.

In FIG. 3 , a boost converter is shown as an example of the part other than the inductor selection circuit. If it is replaced with a circuit of a different structure from the boost converter, for example, buck, buck-boost, sepic, zeta, flyback, etc., the inductor selection circuit part of FIG. 3 and the part outside the inductor selection circuit are in the circuit to be replaced Correspondingly, the location and structure in the circuit may be changed differently.

4 is a diagram illustrating an inductor selection configuration in a solar cell charging mode and a grid charging mode according to an embodiment of the present invention.

4A is a diagram illustrating a selection configuration of an inductor when PV generated power is applied.

As shown in FIG. 4A , on the premise that photovoltaic power generation is being performed during the normal daytime when the sun is shining, the first switch 410 may select and conduct the _{inductor L MPPT .}

At this time, the input signal 'solar power (PV)' input through the photovoltaic power generation is input without going through the Rectifier 420, and the PV Controller identifies it as the PV Charge Mode, and the inductor L _{MPPT in the first switch 410} can be controlled to select

In FIG. 4A , a relay or other switch may be applied to the connection point between the PV and the circuit on the roof of the vehicle so that the PV and the circuit can be more stably connected.

4B is a diagram illustrating an inductor selection configuration when an EV charger power is applied.

As shown in FIG. 4B , as the charging gun is inserted into the charging port of the electric vehicle, the first switch 410 may select and conduct the _{inductor L PFC.}

At this time, the input signal 'Grid' input from the charging gun is an AC series, and is rectified into a rectified series through a Rectifier 420 and is input, and the OBC Controller identifies it as a Grid Charge Mode, and the first switch 410 ) can be controlled to select the inductor L _PFC.

If the charging gun insertion is released, the first switch 410 may be reselected by changing the _{inductor L PFC} to the inductor L _MPPT.

In FIG. 4B, a relay or other switch may be applied to the connection contact of the charging gun and the rectifier circuit to more stably connect the charging gun and the rectifier circuit.

When there is an input through a renewable energy source such as PV and an input through a grid source such as an EV charger, the selective converter device 100 of the present invention selects an optimal design inductor according to each input capacity to maximize power conversion efficiency. can

Hereinafter, a work flow for designing the selective converter device 100 for an electric vehicle OBC according to embodiments of the present invention will be described in detail with reference to FIG. 5 .

5 is a flowchart illustrating a power conversion method of a selective converter device for an electric vehicle OBC according to an embodiment of the present invention.

First, in the first switch, which is a component of the selective converter device 100, the type of charging mode is identified _{, and any one of an inductor L MPPT} for MPPT control and an inductor L _PFC for PFC control is selectively conducted ( 510). This step 510 may be a process in which the first switch determines the type of mode in which the electric vehicle is charged, and determines an inductor for optimal charging according to the checked mode.

_{Basically, the first switch selects and conducts the inductor L PFC} for PFC control when the electric vehicle is charging electricity, and only when the electric vehicle is charged by solar power, the inductor for MPPT control It can be conducted by selecting _{L MPPT.}

According to an embodiment, when solar power (PV) is input from the solar cell, the first switch may identify the charging mode as the solar cell charging mode and select the _{inductor L MPPT for controlling the MPPT.} That is, the first switch may select and conduct _{inductor L MPPT} on the premise that solar power generation is being performed during normal daytime when the sun is shining.

In addition, when a grid is input from the power battery, the first switch may identify the charging mode as the grid charging mode and select the _{inductor L PFC for controlling the PFC.} That is, the first switch may select and conduct the _{inductor L PFC} while the charging gun is inserted into the charging port of the electric vehicle and electric charging is performed from the power battery of the charging station. If the charging gun insertion is released, the first switch may be changed from the inductor L _{PFC to the inductor L MPPT} and reselected to conduct.

In another embodiment, the first switch may identify the charging mode as the solar cell charging mode when an input signal from the outside is input without passing through the rectifier located at the front end. That is, the first switch may select and conduct the _{inductor L MPPT} when it is determined that the solar power of the DC series output by the solar cell is input as an input signal and processing in the rectifier is unnecessary.

In addition, when the input signal is input via the rectifier, the first switch may identify the charging mode as a grid charging mode. That is, the first switch determines that an AC grid is input as an input signal, and as the AC grid is rectified through a rectifier, it is confirmed that electrical charging is being made, and the inductor L _PFC is selected to conduct can

Also, in the second switch, which is another component of the selective converter device 100, a PWM (Pulse Width Modulation) pulse corresponding to the type of the charging mode is selectively applied to the MOSFET ( 520 ). This step 520 may be a process in which the second switch determines a PWM pulse with a MOSFET according to the type of mode in which the electric vehicle is charged.

As an example, when the inductor L _MPPT is selected by the first switch to conduct, the second switch selects a PWM _MPPT pulse for MPPT control and applies it to the MOSFET, thereby accumulating the solar power (PV) of the MOSFET , and construct a circuit in parallel with the inductor L _{MPPT . That is, the second switch selects the PWM MPPT} pulse for MPPT control and applies it to the MOSFET when the battery is charged according to solar power generation, so that the MOSFET and the inductor L _MPPT are configured in parallel to accumulate solar power.

As another example, when the inductor L _PFC is selected and conducted by the first switch, the second switch selects a PWM _PFC pulse for PFC control and applies it to the MOSFET, thereby accumulating a grid. to form a circuit in parallel with the inductor L _PFC. That is, when the second switch is applied to the MOSFET for PFC control when the battery is charged according to the grid, the MOSFET and the inductor L _PFC are configured in parallel to accumulate the grid.

According to an embodiment of the present invention, by optimally selecting an inductor by distinguishing whether it is PFC control or MPPT control, high power conversion efficiency can be obtained not only in PFC control mode but also in MPPT control mode, selective type for electric vehicle OBC It is possible to provide a converter device and a method for converting power of a selective converter device for an electric vehicle OBC.

In addition, according to the present invention, even when there is an input of PV, which is a new power source that shares a grid source such as an EV charger, an optimal design inductor is selected according to each input capacity to maximize power conversion efficiency. can do it

The power conversion method of the optional converter device for an electric vehicle OBC according to the embodiment is implemented in the form of a program command that can be executed through various computer means and can be recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiment, or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floppy disks. - includes magneto-optical media, and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Software may comprise a computer program, code, instructions, or a combination of one or more thereof, which configures a processing device to operate as desired or is independently or collectively processed You can command the device. The software and/or data may be any kind of machine, component, physical device, virtual equipment, computer storage medium or apparatus, to be interpreted by or to provide instructions or data to the processing device. , or may be permanently or temporarily embody in a transmitted signal wave. The software may be distributed on a networked computer system, and may be stored or executed as a power conversion method of an optional converter device for distributed electric vehicle OBC. Software and data may be stored in one or more computer-readable recording media.

As described above, although the embodiments have been described with reference to the limited drawings, those skilled in the art may apply various technical modifications and variations based on the above. For example, the described techniques are performed in an order different from the power conversion method of the optional converter device for an electric vehicle OBC described, and/or the described components of the system, structure, device, circuit, etc. are described in the electric vehicle OBC Appropriate results may be achieved even if combined or combined in a different form with the power conversion method of the optional converter device for use, or replaced or substituted by other components or equivalents.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

100: Selective converter device for electric vehicle OBC
110: first switch 120: second switch

Claims (11)

Claim that the solar power to the direct current series output by a solar cell, when the input without passing through a rectifier (Rectifier) which is located at the front end, to identify the charging mode to the solar cell charging mode, conducting the inductor L _MPPT for the MPPT control 1 switch; and
_{A second switch that selects a PWM MPPT} pulse for MPPT control and applies it to a MOSFET so that the MOSFET for accumulating solar power (PV) is circuited in parallel with _{the inductor L MPPT}
including,
The first switch is
When the AC-series grid is input via the rectifier, the charging mode is identified as the grid charging mode, and the inductor L _PFC for PFC control is conducted,
The second switch is
_{By selecting a PWM PFC} pulse for PFC control and applying it to a MOSFET, the MOSFET accumulating a grid is configured as a circuit in parallel with _{the inductor L PFC}
Optional converter device for electric vehicle OBC. delete delete delete delete (i-1) In the first switch, when the solar power of the DC series output by the solar cell is input without passing through the rectifier located at the tip, the charging mode is identified as the solar cell charging mode, and MPPT conducting an inductor L _{MPPT for control;}
(i-2) in a second switch, _{selecting a PWM MPPT} pulse for MPPT control and applying it to a MOSFET, thereby configuring the MOSFET for accumulating solar power (PV) in parallel with _{the inductor L MPPT;}
(ii-1) in the first switch, when an AC grid is input via the rectifier, identifying a charging mode as a grid charging mode and conducting an _{inductor L PFC for PFC control;} and
(ii-2) in the second switch, _{selecting a PWM PFC} pulse for PFC control and applying it to a MOSFET, thereby accumulating a grid, and configuring a circuit in parallel with _{the inductor L PFC}
Power conversion method of an optional converter device for electric vehicle OBC comprising a. delete delete delete delete A computer-readable recording medium recording a program for executing the method of claim 6 .

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