KR101974506B1 - Hybrid charging system for electric car - Google Patents

Abstract

The present invention relates to a hybrid charging system for an electric vehicle capable of reducing the load time for a system power supply and reducing the charging time. The hybrid charging system includes an AC power supply for supplying AC power from the grid power supply, An ESS for receiving and storing the DC power supplied from the DC power supply unit or the DC power converted from the PCS; An inverter receiving at least one DC power from at least one of a DC power source converted from the PCS, a DC power source supplied from the DC power source, and a DC power source stored in the ESS to convert the AC power into an AC voltage and outputting the AC voltage; A transformer for receiving and outputting an AC voltage and for outputting an AC voltage; an AC voltage output from the transformer as D A smoothing circuit for smoothing and DC-outputting the DC voltage outputted from the rectifier, and a rectifier for receiving and outputting an AC voltage outputted from the transformer and forming a resonance with an external power supply coil A resonance capacitor, first and second switches respectively formed between the transformer and the rectifier and between the transformer and the resonance capacitor, and a control unit for controlling the wired or wireless charging system by selectively turning on / off the first and second switches And a control unit.

Description

[0001] Hybrid charging system for electric car [0002]

The present invention relates to a hybrid charging system for an electric vehicle, and more particularly, to a hybrid charging system for an electric vehicle, in which charging time is shortened by using a renewable energy source and an energy storage device (ESS) And more particularly to a hybrid charging system for an electric vehicle.

Generally, automobiles use gasoline or diesel as a fuel. Gasoline or diesel generates harmful gas when it is burned, causing not only air pollution but also crude oil which makes gasoline or diesel. The development of the electric vehicle is completed and is in operation as a solution.

An electric vehicle needs to be charged with electric power for operation, and the electric charging method can be classified into a constant charge charging stand and a rapid charging charger.

First, the charging stand, which is a full charging type, converts electric energy of AC 220V or 380V supplied from a commercial AC power system into a DC power using a charger mounted in the vehicle and then charges the battery.

On the other hand, the rapid charging method is a charging method in which a charger for charging a vehicle without installing a charger in the vehicle itself is connected to an AC-DC converter that converts an AC power source to a DC power source, DC converter is used to output a DC voltage corresponding to the charging power of the electric vehicle battery in the charger.

Therefore, the battery can be charged in a short time because a large current can be supplied as compared with the charger mounted in the vehicle, but a DC-DC converter is included in the charger, which is bulky and heavy.

Therefore, in the case of using electric power in a home for charging a battery in an electric vehicle, it is a slow charge type, but it takes a long time and the battery must be charged frequently due to the limit of the travel distance which can be moved by one charge of the battery.

Also, as electric vehicles become more common, there is a growing need for battery charging stations such as existing gas stations. In the construction of such a charging station, in order to charge a large number of electric vehicles in a large-scale place such as an apartment and apartment house parking lot, a company building parking lot, a public facility parking lot, etc. in the existing downtown, a large amount of electric power is required to charge the electric vehicle do.

In order to obtain such electric power, it is necessary to install additional transmission and distribution lines, management facilities for managing and controlling electric power supply, and expensive installation cost due to securing a place for building a plurality of charging stations, .

FIG. 1 is a diagram showing a system for supplying electric power and a method for charging an electric vehicle to form a charging infrastructure.

As shown in FIG. 1, a large-scale charging infrastructure is required to be built in the urban area because of a large amount of vehicle traffic. For this purpose, it is essential to provide stable electric power for charging and secure site for electric vehicle charging.

Therefore, in order to build a large-scale charging infrastructure in the existing downtown area, an electric vehicle charging infrastructure implementation technique that enables stable large-capacity electric power supply by linking the electric power supply network of the railway infrastructure already built and operated in the city, have.

In order to supply 22.9kV AC with electric power from Korea Electric Power Corporation (KEPCO), Urban Railway Substation uses a rectifier to supply electric power for 1,500V of electric power for direct electric vehicles, electric power for general electric facilities such as lighting, AC three phase 6,600V (22,900V) power is converted and supplied.

Also, in case the electric power supply company can not supply electric power, the urban railway substation establishes the communication system between the substation and the nearby substation, and between the electricity room and the neighboring electricity room to provide stable power supply. .

In addition, a centralized remote monitoring and control system is installed and integrated management is performed to comprehensively manage and operate the monitoring and control of each facility and the power consumption.

The method of supplying electric power for charging an electric vehicle utilizing the DC power supply system can be largely configured in two ways. The first method is a method of drawing electric power from the DC 1500V feeding bus of the secondary side of the rectifier and converting the voltage to various DC voltages required for rapid charging of the electric vehicle by using a DC-DC converter. In the high-voltage power distribution system that supplies electric power to the electric equipment, it converts power to 6,600 (22,900) / 380V or 6,600 (22,900) / 220V voltage by using a distribution transformer to supply power to the existing rapid charger and slow charger.

While electric cars take a long time to charge, the distance that they can travel on a single charge is short. Therefore, an electric vehicle needs to charge frequently, and it takes a lot of time to charge the battery to operate the vehicle once.

In addition, a large-capacity feeder inverter is required to increase the capacity of the battery and to shorten the charging time. As the capacity of the feeder inverter increases, the load increases and a large-capacity system power source is required.

On the other hand, the feeder inverter does not always operate as a constant load, but acts as a large-capacity load only when there is a charge demand, and the grid power must be able to feed the maximum load even if it is not a constant load.

In addition, if a large load is intermittently applied, it may affect the system power source, and the power supply may be difficult depending on the local environment in which the feeder inverter is installed.

[Patent Document 1] Registered Patent Publication No. 10-1219284 (filed on Mar. 01, 201, entitled "Multifunction Charging Device for Electric Vehicle for DC Distribution Using a Large Capacity DC-DC Converter)

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an electric vehicle capable of reducing a load on a system power source and reducing a charging time by using a renewable energy source and an energy storage device, And to provide a hybrid charging system.

According to another aspect of the present invention, there is provided a hybrid charging system for an electric vehicle, comprising: an AC power supply unit for supplying AC power from a system power source; a DC power supply unit for generating and supplying DC power from a renewable energy source; An ESS for receiving and storing the DC power supplied from the DC power supply unit or the DC power converted from the PCS, and a DC power supply unit for converting the DC power supplied from the PCS, An inverter for receiving at least one of DC power supplied from a supply unit and DC power stored in the ESS into an AC voltage and outputting the AC voltage; and a transformer for receiving and outputting 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 a DC voltage output from the transformer, a resonance capacitor for receiving an AC voltage output from the transformer, forming a resonance with an external power supply coil, and outputting a resonance capacitor between the transformer and the rectifier, And a control unit for controlling the wired or wireless charging system by selectively turning on and off the first and second switches.

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

That is, by using a renewable energy source and an energy storage device together with the system power supply, it is possible to reduce the load on the system power supply and reduce the charging time.

FIG. 1 is a diagram that classifies a system for supplying power to constitute a charging infrastructure and a charging system for an electric vehicle
2 is a block diagram schematically showing a hybrid charging system for an electric vehicle according to the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

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

2, the hybrid charging system for an electric vehicle according to the present invention includes an AC power supply 110 for supplying AC power, a DC power supply 120 for supplying DC power from a renewable energy source, A PCS 130 that receives AC power from the AC power supply unit 110 and converts the AC power into DC power and outputs the converted DC power, a DC power supply unit 120, At least one of DC power converted from the PCS 130 or DC power supplied from the DC power supply unit 120 and DC power stored in the ESS 140, A transformer 160 for receiving and outputting an AC voltage outputted from the inverter 150 and outputting the dropped AC voltage; and a transformer 160 for converting the AC voltage outputted from the transformer 160 into an AC voltage, AC voltage to be A smoothing circuit 180 for smoothing and DC-outputting the DC voltage output from the rectifier 170; a smoothing circuit 180 for converting the AC voltage output from the transformer 160 into a DC voltage, And a resonance capacitor 190 connected between the transformer 160 and the resonator 170 and between the transformer 160 and the resonance capacitor 190. The resonance capacitor 190 is connected between the resonance capacitor 190 and the external power supply coil 190, And a control unit 210 for controlling the wired or wireless charging system by selectively turning on and off the first and second switches 201 and 202. The first and second switches 201 and 202 are connected to the first and second switches 201 and 202,

The DC power supply unit 120 includes a solar cell 121 for producing DC power from solar light and an MPPT control unit 122 for receiving DC power produced from the solar cell 121 and controlling and outputting MPPT .

The MPPT control unit 122 converts the voltage of the solar cell 121 into a DC bus voltage of the feed inverter and supplies the DC bus voltage to the feed inverter and has an MPPT function for each of the solar cells 121.

When the solar cell 121 generates electricity, the ESS 140 is charged in the ESS 140 when the ESS 140 is not in the full charge state. When the ESS 140 is in the full charge state, It is also possible to sell the produced power by outputting the power.

The PCS 120, the inverter 150, the transformer 160, the rectifier 170, the smoothing circuit 180, the resonant capacitor 190, and the first and second switches 201 and 202 constitute one feeder inverter .

The power supply inverter controls the power stored in the DC power supply unit 120 and the ESS 140 to be supplied to the electric vehicle in preference to the grid power so as to reduce the load on the system when charging is requested from the electric vehicle.

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 supplied from the AC power supply unit 110 supplies electric power of 22,900 V or 6,600 V to the electric room and converts it into 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.

The ESS 140 is made of a lithium battery and is generally environmentally friendly because it is made of a lead acid battery and has no harmful substance. The ESS 140 has a high efficiency characteristic that can be rapidly charged, and can solve the danger such as ignitability and explosion.

Here, the ESS 140 is not limited to a lithium battery, but may be a nickel metal hydride battery (NiMH).

The ESS 140 can receive and store electrical energy generated from the solar cell 110 and electricity supplied from the PCS 130 that converts the AC power supplied from the AC power supply unit 110 into DC power at midnight .

The ESS 140 includes a battery management unit (not shown) for ensuring safety with high efficiency charging and discharging through control of the ESS 140. The battery management technology can be roughly divided into two types .

First, it can be divided into heat management control which enables equal performance of the weak battery by uniform cooling and second state of charge (SOC) control which determines the state of the battery and operates at the optimum efficiency point.

Meanwhile, the ESS 140 is composed of a plurality of batteries. When the batteries are not fully charged, the ESS 140 charges the battery from the system power supply at a time when the electric vehicle is not charged, thereby maintaining the full charge state. Especially, the battery is fully charged in the night time zone by using the cheap electricity rate in the night time zone.

The battery management unit checks the SOC (State Of Charge) of the battery according to external control and controls the battery charging / discharging operation.

Meanwhile, the AC power supplied through the AC 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 AC 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 200 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 secured.

The rectifier 170 includes a plurality of thyristor elements. The rectifier 170 receives a DC voltage from the transformer 160, converts the DC voltage into an AC voltage, and outputs the AC voltage.

The smoothing circuit 180 serves to smoothly receive the 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. Meanwhile, when the vehicle is stopped at a predetermined position, that is, at a place where the power supply coil 200 is installed, charging is performed by a wireless charging method. When a connector is connected to an automobile, the first and second switches 201, 202 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 201 and 202, but also the entire power supply inverter, and controls the operation of the feeder inverter It is possible.

A measuring module (not shown) is provided at the output terminals of the smoothing circuit 180 and the resonance capacitor 190 to measure the amount of power output. And the amount of power consumed by the battery is measured together.

The transformer 160 reduces the AC power supplied from the energy source to a predetermined value and supplies AC voltage to the load by boosting the AC voltage output from the inverter 150 to a predetermined value.

The rectifier (170) is an electric circuit element or device made by focusing on a rectifying action to obtain DC power from AC power. The rectifier (170) has a function of passing current only in one direction, and has an AC power Is rectified to convert it into a DC power source.

That is, the rectifier 170 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 170 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 170 may be composed of one element such as a diode. However, in order to effectively rectify the rectifier 170, 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 provided between the rectifier 170 and the smoothing circuit 180. The DC / DC converter performs DC / DC conversion of the rectified power by the rectifier 170 Can be supplied to the smoothing circuit (180). 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 180 is transferred 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 (150) has three inverter modules each composed of two switching elements when the connected driving motor is of three phases. The inverter 150 converts the DC power converted by the PCS 130 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.

And may further include an input filter (not shown) for removing noise at an input terminal of the rectifier 170. Here, the input filter is an EMI (Electro-Magnetic Interference Filter) composed of an inductor and / or a capacitor.

The rectifier 170 may include full-bridge diodes. That is, the rectifier 170 preferably constitutes a full-wave rectification circuit. Of course, the rectifier 170 may constitute a half-wave rectifying circuit with several diodes. The rectifier (170) supplies the smoothing circuit (180) for smoothing the AC power rectified by the full-bridge diode. The smoothing circuit 180 may be replaced by one capacitor.

Meanwhile, when charging the battery of the electric vehicle with the wireless charging system, the AC power output through the resonance capacitor 190 is supplied to the power supply coil 200. The power supplied to the power supply coil 200 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 200 can be embedded in a predetermined space such as a parking lot for an electric car or a garage. In this embodiment, the power supply coil 200 is buried in the ground, but the present invention is not limited to this, and the power supply coil 200 may be embedded in a space such as a side wall or the like.

The power supply coil 200 may have a structure in which a Litz cable is wound around 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 switch gear 203 is provided between the AC power supply unit 110 and the PCS 130. The switchgear 203 serves to cut off power from the outside and to apply power to the outside.

The switch gear 203 may be one or more of a relay, an electromagnetic switch (MS), and an insulated gate bipolar transistor (IGBT).

Meanwhile, in the embodiment of the present invention, it is explained that the solar cell 121, that is, electricity is produced using light energy, but the present invention is not limited to this, and electricity can be produced using geothermal heat or solar heat. In addition, DC power can be produced using wind, tidal and hydraulic power.

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: AC power supply unit 120: DC power supply unit
130: PCS 140: ESS
150: inverter 160: transformer
170: rectifier 180: smoothing circuit
190: Resonant capacitor 200: Power supply coil

Claims (6)

An AC power supply for supplying AC power from the system power supply,
A DC power supply unit for producing and supplying DC power from a renewable energy source,
A PCS which receives the AC power and converts the DC power into DC power,
An ESS for receiving and storing the DC power supplied from the DC power supply unit or the DC power converted from the PCS,
An inverter receiving at least one DC power from at least one of a DC power source converted from the PCS, a DC power source supplied from the DC power source, and a DC power source stored in the ESS,
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,
A control unit for controlling the wired or wireless charging system by selectively turning on / off the first and second switches;
A switchgear provided between the power supply unit and the PCS for interrupting power flowing from the outside and for inputting power to the outside;
And a DC / DC converter configured between the rectifier and the smoothing circuit,
When the vehicle stops at the place where the power supply coil is installed, charging is performed by a wireless charging method. When a connector is connected to the automobile, the first and second switches are automatically turned on or off to charge the battery Wherein the controller controls the entire power feed inverter and controls the operation of the feed inverter by receiving information transmitted from outside through communication during charging. delete  The hybrid charging system of an electric vehicle according to claim 1, further comprising a measurement module configured to measure an amount of power output to the output terminals of the smoothing circuit and the resonance capacitor. delete delete [2] The apparatus of claim 1, wherein the DC power supply unit comprises a solar cell for generating DC power from sunlight, and an MPPT control unit for receiving DC power produced from the solar cell, Hybrid charging system for cars.

Images