KR20180130246A - Charging system for electric car - Google Patents

Abstract

The present invention relates to a charging system for an electric vehicle in which a wired charging method and a wireless charging method can be selectively used in one power feeding inverter so as to provide convenience in use. The system comprises: a power supply unit supplying AC power; a PCS receiving the AC power and converting the AC power into DC power so as to output the DC power; an inverter receiving the DC power converted in the PCS, converting the DC power into an AC voltage and outputting the AC voltage; a transformer receiving the AC voltage output from the inverter, and insulating, dropping, and outputting the AC voltage; a rectifier converting the AC voltage output from the transformer into a DC voltage and outputting the DC voltage; a smoothing circuit receiving and smoothing the DC voltage output from the rectifier so as to output the DC voltage; a resonant capacitor receiving the AC voltage output from the transformer, forming a resonance with an external power supply coil and outputting the resonance; first and second switches respectively formed between the transformer and the rectifier and between the transformer and the resonant capacitor; and a control unit controlling the wired or wireless charging method by selectively turning on/off the first and second switches.

Description

[0001] Charging system for electric car [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging system for an electric vehicle, and more particularly, to a charging system for an electric vehicle which is capable of charging by wire or wirelessly.

Today, electric vehicles are attracting attention as new means of transportation. Electric energy is an eco-friendly energy source that can replace existing fossil fuels that cause environmental pollution. Electric vehicles use such electricity as fuel, Does not occur. Therefore, electric vehicles are expected to play an increasing role as eco-friendly vehicles.

Various charging methods are used to charge the battery of an electric vehicle. The charging method is a method in which a cable of a charger installed in a charging station is directly connected to a vehicle (a wired charging method), an electromagnetic induction generated by a primary coil and a secondary coil And a non-contact charging method (wireless charging method) using the phenomenon.

This wire charging method is a method of charging a battery by connecting a feed cable of a direct charger to a connector of an automobile. The wireless charging method is a method using electromagnetic induction of a power feeding and a current collecting coil. When a high frequency current is supplied to a power feeding coil, And rectifies the induced alternating current into direct current to charge the battery.

1 is a view for explaining a charging method of a general electric vehicle.

Referring to FIG. 1, an electric vehicle 10 may be charged at a charging station in which electric vehicle supply equipment (EVSE) 20 is disposed. To this end, a charging cable connected to the electric vehicle charging facility 20 may be connected to the inlet of the electric vehicle 10.

On the other hand, it takes about 7 hours to complete charging the electric vehicle 10, and about 30 minutes in the case of the fast charging method. When multiple electric vehicles enter the charging station, there is a possibility of collision between vehicles. There is a risk of electric shock if another vehicle crashes into an electric vehicle being charged with a high voltage (e.g., several hundred volts) and a high current (e.g., a few hundred amperes).

[Patent Document 1] Registration No. 10-1221041 (Date of Registration: 2013. 01.04)

[Patent Document 2] Japanese Patent Application Laid-Open No. 10-1610397 (Date of Registration: 2016.04.01)

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a charging system for an electric vehicle in which a wired charging method and a wireless charging method can be selectively used in one power feeding inverter, There is a purpose.

According to another aspect of the present invention, there is provided an electric vehicle charging system including a power supply unit for supplying AC power, a PCS for receiving the AC power and converting the AC power into DC power, A rectifier for converting an AC voltage output from the transformer into a DC voltage and outputting the converted AC voltage; a transformer for converting the AC voltage output from the transformer into a DC voltage and outputting the AC voltage; A smoothing circuit for smoothing and DC-outputting the DC voltage output from the rectifier, a resonance capacitor for receiving an AC voltage output from the transformer, forming a resonance with an external power supply coil and outputting the rectified voltage, And first and second switches respectively provided between the transformer and the resonant capacitor, And a control unit for controlling the wired or wireless charging system by selectively turning on / off the second switch.

The electric vehicle charging system according to the embodiment of the present invention has the following effects.

That is, the wired charging method and the wireless charging method can be selectively used for one power supply inverter, thereby making it convenient to use.

1 is a view for explaining a charging method of a general electric vehicle;
2 is a block diagram schematically showing a charging system of an electric vehicle according to the present invention;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, detailed description of well-known functions or constructions that may obscure the subject matter of the present invention will be omitted. It should be noted that the same constituent elements are denoted by the same reference numerals as possible throughout the drawings.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and the inventor is not limited to the meaning of the terms in order to describe his invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention, and not all of the technical ideas of the present invention are described. Therefore, It is to be understood that equivalents and modifications are possible.

2 is a schematic diagram showing a charging system of an electric vehicle according to the present invention.

2, the charging system for an electric vehicle according to the present invention includes a power supply unit 110 for supplying AC power, an AC power supply unit 110 for converting AC power to DC power, An inverter 130 for converting an AC voltage output from the inverter 130 into an AC voltage and converting the AC voltage into an AC voltage, A rectifier 150 for converting the AC voltage output from the transformer 140 into a DC voltage and outputting the DC voltage and a rectifier 150 for smoothing and DC outputting the DC voltage outputted from the rectifier 150, A resonant capacitor 170 receiving AC voltage output from the transformer 140 and forming a resonance with the external power supply coil 180 and outputting the AC voltage to the transformer 140 and the rectifier 150; And transformers (1 The first and second switches 191 and 192 are selectively turned on and off between the first and second switches 191 and 192 and the resonant capacitor 170, And a control unit 200 for controlling the control unit 200.

The PCS 120, the inverter 130, the transformer 140, the rectifier 150, the smoothing circuit 160, the resonant capacitor 170, and the first and second switches 191 and 192 are connected to one power supply Configure the inverter.

Meanwhile, an electric vehicle is parked in an adjacent area where a power supply inverter is installed, and is connected to a connector of an automobile to connect a power cable to a vehicle, thereby charging the battery installed therein. And the like.

The AC power supply of the power supply unit 110 supplies electric power of 22,900 V or 6,600 V to the electric room and converts the electric power to 380 V or 220 V, which is a voltage for a general electric facility in the electric room to supply electric power. In addition, in order to prevent the electric power supply to the corresponding electric room from being interrupted, an extension electric power distribution line capable of receiving electric power from a neighboring electric room is constructed, so that the electric power can be stably supplied without power failure.

Meanwhile, the AC power supplied through the power supply unit 110 may have a different voltage depending on the facilities of the power supply inverter, and the magnitude of the voltage may be sufficiently increased for rapid charging.

The capacity of the power supply inverter is a capacity capable of charging one or a plurality of vehicles at the same time, and is usually about 50 kW based on a vehicle of about ten cars, and may have a capacity higher than that of the technology.

Generally, the power supply unit 110 draws a power supply line from a power supply bus installed along a line to supply electric power. The voltage level of the power supply bus can be changed from time to time according to electric power consumption of the electric vehicle.

Meanwhile, the power supply coil 180 is installed in the running zone of the road so that the electric vehicle can receive power while driving. Preferably close to the intersection of the road. In the intersection, when the vehicle stops or slows down to the signal waiting area and the signal waiting time is long, the vehicle leaves the intersection by repeating the stopping and slowing down. Therefore, Time can be increased.

The rectifier 150 includes a plurality of thyristor elements. The rectifier 150 receives a DC voltage from the transformer 140, converts the DC voltage into an AC voltage, and outputs the AC voltage.

The smoothing circuit 160 serves to smoothly receive a rectified voltage of the thyristor rectifying circuit.

The control unit includes a function of controlling the amount of charge according to the voltage of the battery mounted on the vehicle. On the other hand, when the vehicle is stopped at a predetermined position, that is, at a place where the power supply coil 180 is installed, charging is performed using a wireless charging method. When a connector is connected to a vehicle, the first and second switches 191, 192) is automatically turned ON or OFF to charge the battery of the vehicle.

In addition, the control unit controls not only the operation of the first and second switches 191 and 192 but also the entire power feed inverter, and controls the operation of the power feed inverter by receiving information transmitted from the outside during charging It is possible.

A measuring module (not shown) is configured to measure the amount of power output from the output terminals of the smoothing circuit 160 and the resonance capacitor 170. The measuring module supplies a high-voltage direct current or alternating- And the amount of power consumed by the battery is measured together.

The transformer 140 serves to reduce the AC power supplied from the energy source to a predetermined value and to supply the alternating voltage output from the inverter 130 to a predetermined value to provide a load.

The rectifier (150) is an electric circuit element or device made to focus on a rectifying operation to obtain DC power in AC power. The rectifier (150) has a function of passing a current in only one direction, and an AC power Is rectified to convert it into a DC power source.

That is, the rectifier 150 is a device or device that periodically converts alternating currents that change in both positive and negative directions into direct current having only one direction. The rectifier 150 has a small forward resistance and a large reverse resistance, And a forward direction in which the current flows smoothly and a reverse direction in which the current hardly flows are distinguished from each other in accordance with the direction of the applied voltage.

The rectifier 150 may be composed of one element such as a diode. However, in order to effectively rectify the rectifier 150, a plurality of elements are arranged in a specific arrangement on a normal circuit. Silicon diodes are used in most power supplies and thyristors are widely used in control rectifier applications.

Thyristors are sometimes referred to as Silicon Controlled Rectifiers (SCRs), and are seen as a type of silicon controlled rectifier. The thyristor is composed of three terminals, anode, cathode and gate. When a signal is applied to the gate, a reverse current is applied to the main circuit without supplying a continuous gate current, currrent).

Here, the three-phase AC power source is an AC power source generated by a three-phase alternating-current generator having the same voltage and the same frequency and amplitude as the current and having a phase difference of 120 ° from each other. The weight of the necessary wires is small and the number of jets consumed in the line is small and the electric motor using the three-phase alternating current is much better than the single phase in the case of the electric motor.

A DC / DC converter (not shown) may be formed between the rectifier 150 and the smoothing circuit 160. The DC / DC converter converts the power rectified by the rectifier 150 into DC / DC Can be supplied to the smoothing circuit (160). The DC / DC converter is an electronic circuit device that converts a DC voltage of a certain voltage to a DC voltage of a different voltage. The DC / DC converter uses a current control of a buck converter, which is a DC / DC converter, charge relay function and main relay function.

The DC power outputted through the smoothing circuit 160 is transmitted to a battery mounted on the vehicle through a feed cable to be charged. The battery supplies DC power to the motor of the vehicle. A battery generally forms a set in which a plurality of unit cells are connected in series and / or in parallel. The plurality of unit cells are managed to maintain a constant voltage by a battery management system (BMS).

That is, the battery management system causes the battery to emit a constant voltage. The battery is preferably a secondary battery capable of charging and discharging, but is not limited thereto. As the battery, a nickel metal hydride (Ni-MH) battery or a lithium ion (Li-ion) battery is generally used.

The inverter 130 includes three inverter modules each having two switching elements when the driving motor connected is three-phase. The inverter 130 converts the DC power converted by the PCS 120 into a three-phase AC power according to a control signal. Free-wheeling diodes are connected in parallel to the switching elements. MOSFETs, IGBTs, and the like are mainly used as the switching elements. The switching elements receive the control signal from the control unit and are turned on or off according to the control signal. The control signal is a signal for controlling the duty ratio of the switching elements.

The freewheeling diodes are connected in parallel to each of the switching elements to form current paths when they are turned off by switching to consume the residual current.

The rectifier 150 may further include an input filter (not shown) for removing noise. Here, the input filter is an EMI (Electro-Magnetic Interference Filter) composed of an inductor and / or a capacitor.

The rectifier 150 may include full-bridge diodes. That is, the rectifier 150 preferably constitutes a full-wave rectification circuit. Of course, the rectifier 150 may constitute a half-wave rectifying circuit with several diodes. The rectifier (150) supplies the smoothing circuit (160) for smoothing the AC power rectified by the full-bridge diode. The smoothing circuit 160 may be replaced by one capacitor.

Meanwhile, when the battery of the electric vehicle is charged by the wireless charging method, the AC power output through the resonant capacitor 170 is supplied to the power supply coil 180. The electricity supplied to the power supply coil 180 is AC, Can be converted into high-frequency power and supplied by the high-frequency power conversion device. High-frequency power is high in energy efficiency and is suitable for supplying electricity by magnetic induction. The power supply coil 180 may be embedded in a predetermined space such as a parking lot for an electric vehicle or a garage. In this embodiment, the power supply coil 180 is buried in the ground, but the present invention is not limited to this, and the power supply coil 180 may be buried in a space such as a side wall or the like.

The inside of the power supply coil 180 may be a structure in which a Litz cable is wound on a core formed of ferrite. The RITZ cable is a wire which is coated with a special insulator, such as thin enamel wire or polyurethane wire having a diameter of about 0.1 mm, several tens to several hundreds of strands one by one, or wound with a silk thread. The Ritz cable is intended to physically increase the surface area, and electrically reduces the skin effect to improve the frequency characteristics.

A switchgear 193 is provided between the power supply unit 110 and the PCS 120. The switchgear 193 functions to cut off power flowing from the outside and to supply power to the outside.

The switch gear 193 may be one or more of a relay, an electromagnetic switch (MS), and an insulated gate bipolar transistor (IGBT).

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or essential characteristics thereof. . Therefore, the embodiments disclosed in the present invention are not intended to limit the scope of the present invention but to limit the scope of the technical idea of the present invention by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

110: Power supply unit 120: PCS
130: inverter 140: transformer
150: rectifier 160: smoothing circuit
170: Resonant capacitor 180: Power supply coil
191, 192: first and second switches 193: switch gear

Claims (5)

A power supply for supplying AC power,
A PCS which receives the AC power and converts the DC power into DC power,
An inverter for receiving the converted DC power from the PCS and converting it into an AC voltage and outputting the AC voltage;
A transformer for receiving an AC voltage output from the inverter,
A rectifier for converting an AC voltage output from the transformer into a DC voltage and outputting the DC voltage,
A smoothing circuit for smoothing and DC outputting the DC voltage output from the rectifier,
A resonance capacitor receiving an AC voltage output from the transformer and forming a resonance with an external power supply coil,
First and second switches respectively provided between the transformer and the rectifier, and between the transformer and the resonant capacitor,
And a control unit for controlling the wired or wireless charging system by selectively turning on / off the first and second switches. The charging system of an electric vehicle according to claim 1, further comprising: a switchgear configured between the power supply unit and the PCS, for interrupting power flowing from the outside and for supplying power to the outside. The charging system of an electric vehicle according to claim 1, further comprising a measuring module configured to measure an amount of power output to the output terminals of the smoothing circuit and the resonance capacitor. The charging system of an electric vehicle according to claim 1, further comprising a DC / DC converter configured between the rectifier and the smoothing circuit. 2. The charging system of an electric vehicle according to claim 1, wherein the controller controls the entire power feed inverter and controls the operation of the power feed inverter by receiving information transmitted from outside through communication during charging.

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