Charging equipment and procedures

Abstract

Charging device comprising: a battery (106) suitable and configured to store DC voltage; first and second motors (101, 102) suitable and configured to operate as a motor or a generator; first and second inverters (103, 104) suitable and configured to operate the first and second motors (101, 102); a voltage transformer (105) suitable and configured to increase the DC voltage of the battery (106) to supply it to the first and second inverters (103, 104) and to increase the DC voltage of the inverter to supply it to the battery (106); and a charging controller (200) suitable and configured to operate the first and second inverters (103, 104) as a booster or generator.to operate voltage amplifiers or to operate the voltage transformer (105) as a step-down converter, according to a voltage which is input via a neutral point of the first and second motors (101, 102) and the voltage of the battery (106), wherein the charging control element (200) is configured to switch off the voltage transformer (105) so that the voltage which is increased by the first inverter (103) or the second inverter (104) charges the battery (106) when the voltage which is input via the neutral point of the first and second motors (101, 102) is less than the battery voltage.

Description

AREA OF INVENTION The present invention relates to charging devices and methods. More specifically, the present invention relates to charging devices and methods for an environmentally friendly vehicle which uses a commercial external energy source connected via a power network formed in the environmentally friendly vehicle to charge a battery, and a method for doing so. BACKGROUND OF THE INVENTION An environmentally friendly vehicle, which includes an electric vehicle, which is a connectable electric vehicle, which offers an improvement in fuel consumption and gas emission stabilization, includes a high voltage / high current power network. The environmentally friendly vehicle uses a connection method that utilizes commercial external electrical power or energy to charge a battery. A charging element is provided on board the environmentally friendly vehicle, which rectifies the commercial external electrical power to provide slow charging via plug-in charging. The on-board charging element, which is located in the environmentally friendly vehicle, includes a high-voltage switch, a choke, a capacitor, an insulation-type transformer, and a cooling system, and housing these components in fixed assemblies is necessary. Furthermore, each component of the on-board charging system is expensive and heavy, resulting in overall increased costs and reduced fuel efficiency. Specifically, the price of the charging element is similar to that of the operating inverter, which has approximately ten times the capacity, in order to increase the cost of the environmentally friendly vehicle, and this weakens its competitiveness. Publication JP 2009 - 120 154 A describes a hybrid vehicle that charges a battery without using a high current-carrying switch in the driving circuit. German patent application DE 10 2009 044 281 A1 describes a device for transmitting energy using power electronics and machine inductance, and a method for manufacturing the same. A drive inverter circuit further includes a charging bus having a first conductor connected to several windings of a first electromechanical device, the charging bus being configured to transmit a charging current to the first electromechanical device or to receive a charging current from it in order to charge a first energy storage device via the first electromechanical device and via a first bidirectional DC-AC inverter. The above information, published in this background section, is intended only to enhance understanding of the background of the invention and may therefore contain information that does not represent the prior art, which is already known to a person skilled in the art in this country. SUMMARY OF THE INVENTION The present invention was carried out with the effort to provide a charging device for an environmentally friendly vehicle which has the advantages of using commercial electrical power or energy supplied via a connection and using a power or energy network within a vehicle, without a separate charging element in an environmentally friendly vehicle. The present invention also offers advantages for minimizing the switching loss of a voltage transformer and an inverter by operating the voltage transformer or the inverter according to a state of input voltage and battery voltage. The present invention also has advantages in providing a charging efficiency by adding a power factor correction (PFC) to the charging control of the inverter and the voltage transformer. A charging device according to an embodiment of the present invention comprises: a battery which is suitable and configured to store a DC voltage, first and second motors which are operated as a motor or a generator, first and second inverters which are suitable and configured to operate the first and second motors, a voltage transformer which is suitable and configured to increase the DC voltage of the battery in order to supply it to the first and second inverters, and to increase the DC voltage of the inverter in order to supply it to the battery, and a charging control element which is suitable and configured to operate the first and second inverters as a booster or a generator.to operate voltage amplifiers, or to operate the voltage transformer as a step-down converter corresponding to a voltage which is input via a neutral point of the first and second motors and the voltage of the battery, wherein the charging control element is configured to switch off the voltage transformer so that the voltage which is increased by the first inverter or the second inverter charges the battery when the voltage which is input via the neutral point of the first and second motors is less than the battery voltage. The charging control unit can control the first and second inverters to be switched off, and can control the voltage transformer to become a step-down converter when the voltage input via the neutral point of the first and second motors exceeds a battery voltage. The charging control unit can forward the voltage, which is input via the neutral point of the first and second motors, to the voltage transformer while the first and second inverters are switched off. The charging control element can control the first and second inverters according to the input voltage of the neutral point, so that the first and second inverters are the voltage amplifiers, and can continuously switch on an upper switching element of the voltage transformer when the battery voltage exceeds the voltage which is input via the neutral point of the first and second motors. The charging control element can control the voltage transformer to increase the voltage and perform the DC voltage transformation to charge the battery when the input voltage of the neutral point of the first and second motors exceeds a battery voltage. The charging control unit can only use the first and second inverters to perform the voltage boost and DC voltage transformation, so that the boosted and DC-transformed voltage is supplied to the battery as a charging voltage when the input voltage, which is entered via the neutral point of the first and second motors, is lower than the battery voltage. The charging control unit can cut off the voltage applied to the neutral point of the first and second motors when it is determined that the battery is fully charged. The charging control unit can operate the first inverter as a booster or voltage amplifier if the battery voltage exceeds the input voltage of the neutral point of the first and second motors and the phase of the input voltage has a positive value (Vin> 0). The charging control element can operate the second inverter as a booster element if the battery voltage exceeds the input voltage of the neutral point of the first and second motors and the phase of the input voltage has a negative value (Vin< 0). A charging method according to an embodiment of the present invention comprises detecting a connection of a charging plug, detecting a voltage input via a neutral point of the first and second motors, and a battery voltage when the connection of the charging plug is detected, and charging a battery by operating the first and second inverters as voltage amplifiers or by operating a voltage transformer as a buck converter, depending on a relationship between a voltage input signal via the neutral point of the first and second motors and a battery voltage, and switching off the voltage transformer so that the voltage increased by the first inverter or the second inverter charges the battery (106) when the voltage input via the neutral point of the first and second motorslower than the battery voltage. According to further training, the input voltage can only be increased by the voltage transformer to charge the battery if the voltage input signal through the neutral point of the first and second motors exceeds the battery voltage. According to further training, the input voltage can only be increased by the first and second inverters to charge the battery if the voltage input signal through the neutral point of the first and second motors is lower than the battery voltage. According to further training, the first and second inverters can maintain a switched-off state, and the voltage input signal through the neutral point of the first and second motors is forwarded to the voltage transformer when the voltage input through the neutral point of the first and second motors exceeds the battery voltage. According to a further development, the first and second inverters can be switched depending on the phase of the input voltage, so that the first and second inverters are operated as boosters or voltage amplifiers, and an upper switching element of the voltage transformer can be controlled to be continuously switched on when the voltage input signal through the neutral point of the first and second motors is lower than the battery voltage. In a state where the voltage input signal through the neutral point of the first and second motors is less than the battery voltage, if the phase of the input voltage is a positive value (Vin< 0), the first inverter can be operated as a voltage amplifier, and if the phase of the input voltage is a negative value (Vin< 0), the second inverter can be operated as a voltage amplifier. A charging method according to an embodiment of the present invention comprises: detecting a connection of a charging plug, detecting a voltage input through a neutral point of the first and second motors, and a battery voltage when the connection of the charging plug is detected, charging a battery by increasing the input voltage by a voltage transformer when the voltage input signal through the neutral point of the first and second motors exceeds the battery voltage, and charging a battery by increasing the input voltage by the first and second inverters, depending on the input voltage, when the voltage input signal through the neutral point of the first and second motors is lower than the battery voltage, and switching off the voltage transformer so that the voltagewhich is increased by the first inverter or the second inverter, charges the battery when the voltage input via the neutral point of the first and second motors is lower than the battery voltage. According to further training, the first and second inverters can be maintained in a switched-off state so that the switching loss does not occur while the input voltage is increased by the voltage transformer. If the first and second inverters increase the input voltage, according to a further development, an upper switching element of the voltage transformer can be controlled to be continuously switched on, so that a switching loss of the voltage transformer does not occur. If the voltage input signal through the neutral point of the first and second motors is lower than the battery voltage, if the phase of the input voltage is a positive value (Vin> 0), then according to a further development, the first inverter can be controlled to increase the input voltage, and if the phase of the input voltage is a negative value (Vin< 0), the second inverter is controlled to increase the input voltage. A charging method according to an embodiment of the present invention comprises: detecting a connection of a charging plug, detecting a voltage input through a neutral point of the first and second motors and a battery voltage when the connection of the charging plug is detected, increasing an input voltage by operating a first inverter or a second inverter as a voltage amplifier, depending on a phase of the voltage signal through the neutral point of the first and second motors, and charging a battery by operating a voltage transformer as a buck converter or to maintain its off state, depending on a relationship between the voltage input signal through the neutral point of the first and second motors and the battery voltage, and switching off the voltage transformer so that the voltage,which is increased by the first inverter or the second inverter, charges the battery when the voltage input via the neutral point of the first and second motors is lower than the battery voltage. If the voltage input through the neutral point of the first and second motors has a positive value (Vin> 0), according to a further development the first inverter can be operated as a voltage amplifier, and if the phase of the input voltage is a negative value (Vin< 0), according to a further development the second inverter can be operated as a voltage amplifier. The voltage transformer can be controlled according to a further development to be a step-down converter, so that the input voltage, which is increased by the first inverter or the second inverter, is suppressed in order to charge the battery when the voltage which is input via the neutral point of the first and second motors exceeds the battery voltage. According to a further development, the voltage transformer can be switched off, and the voltage increased by the first inverter or the second inverter can charge the battery if the voltage input through the neutral point of the first and second motors is lower than the battery voltage. According to a further development, the voltage transformer can forward the voltage, which is increased by the first inverter or the second inverter, to the battery in order to charge the battery if the voltage which is input via the neutral point of the first and second motors is lower than the battery voltage. A charging method according to an embodiment of the present invention comprises: detecting a voltage input through a neutral point of the first and second motors and a battery voltage when a charging plug connection is detected, wherein a first inverter is operated as a voltage amplifier, in a phase of the voltage input through the neutral point of the first and second motors having a positive value (Vin> 0), and operating the second inverter as a voltage amplifier to increase the voltage when the phase of the voltage has a negative value (Vin< 0), wherein the voltage transformer is operated as a buck converter so that the input voltage increased by the first inverter or by the second inverter is suppressed in order to charge the battery when the voltagewhich is input through the neutral point of the first and second motors, exceeds the battery voltage, and the switching off of the voltage transformer, so that the voltage which is increased by the first inverter or the second inverter charges the battery when the voltage which is input through the neutral point of the first and second motors is less than the battery voltage. A charging device according to an embodiment of the present invention comprises: a battery suitable and configured to store a DC voltage; first and second motors suitable and configured to operate as a motor or a generator; an inverter suitable and configured to operate a motor and to boost a voltage supplied to a plug-in device; a rectifier suitable and configured to rectify an AC voltage supplied by the plug-in device to supply it to a neutral point of a motor; and a voltage transformer suitable and configured to boost the DC voltage of the battery to supply it to the inverter, and which supplies the voltage boosted by the inverter to supply it to the battery as a charging voltage, or suppresses the voltage.to supply it to the battery as a charging voltage, and a charging control element which is suitable and configured to operate the inverter as a voltage amplifier, or to operate the voltage transformer as a step-down converter, to supply the battery with a charging voltage depending on the voltage which is input to the neutral point of the motor via the plug-in element and the voltage of the battery, and switching off the voltage transformer so that the voltage which is increased by the inverter charges the battery when the voltage which is input via the neutral point of the motor is lower than the battery voltage. The charging device may also include a switch which disconnects a commercial voltage supplied to a rectifier via a plug-in element, according to the control signal of the charging control element, when it is detected that the charging of the battery is complete. The charging control unit can switch off the inverter to forward the input voltage to the voltage transformer, and can operate the voltage transformer as a buck converter to suppress the input voltage when the voltage input through the neutral point of the motor exceeds the battery voltage. The charging control element can operate the inverter as a voltage amplifier to increase the input voltage and can continuously switch on an upper side power switching element of the voltage transformer so that the voltage increased by the inverter is supplied to the battery to charge it when the voltage input through the neutral point of the motor is lower than the battery voltage. A charging method according to an embodiment of the present invention comprises: detecting a battery voltage and an input voltage, which is transformed to a DC current by a rectifier to be applied through a motor's neutral point when a charging plug is connected; controlling the inverter to be switched off; operating a voltage transformer as a buck converter to suppress the input voltage; supplying the suppressed voltage to the battery to charge it when the input voltage exceeds the battery voltage; increasing the input voltage by operating the inverter as a voltage amplifier; and continuously switching on an upper-side power switching element of a voltage transformer to supply a battery with the increased voltage as a charging voltage.If the input voltage is lower than the battery voltage, the voltage transformer is switched off so that the voltage increased by the inverter charges the battery when the voltage input via the neutral point of the motor (401) is lower than the battery voltage, and, when charging is complete, the transmission of a commercial voltage to the neutral point is prevented. A charging method according to an embodiment of the present invention comprises: detecting a battery voltage and an input voltage, which is transformed to a DC voltage by a rectifier to be applied through a motor's neutral point when a charging plug is connected; increasing the input voltage by operating an inverter as a voltage amplifier; operating the voltage transformer as a buck converter to suppress the input voltage increased by the inverter; supplying the suppressed voltage to the battery to charge it when the input voltage exceeds the battery voltage by comparing the input voltage with the battery voltage; and switching off the voltage transformer to supply the increased voltage to the battery as a charging voltage when the input voltage is lower than the battery voltage.The switching off of the voltage transformer so that the voltage increased by the inverter charges the battery when the voltage input via the neutral point of the motor (401) is less than the battery voltage, and, when charging is complete, preventing the transmission of a commercial voltage to the neutral point. In an environmentally friendly vehicle according to the present invention, a power network arranged therein uses commercial electrical power to charge a battery, so that an on-board charging element is not necessary, costs and weight are reduced, fuel consumption efficiency is improved, and the space utilization efficiency of the vehicle is improved. The present invention also controls the operation of the voltage transformer and the inverter according to the relationship between the input voltage and the battery voltage in order to minimize switching losses and improve the power factor for the input voltage, and therefore the charging efficiency is improved. DEFINITIONS The terminology used herein serves only to describe specific embodiments and is not intended to limit the invention. As used herein, the singular forms "a," "an," and "the" are to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, it is to be understood that the terms "includes" and / or "include" when used in this specification specify the presence of certain features, integers, steps, workflows, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, workflows, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the items listed herein. It is understood that the term "vehicle" or "vehicle-like" or any other similar term as used herein refers to motor vehicles in general, such as passenger cars, including sports vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft (including a variety of boats and ships), aircraft, and the like, as well as hybrid vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other vehicles powered by alternative fuels (e.g., fuels derived from resources other than petroleum). As referenced herein, a hybrid vehicle is a vehicle that has two or more power sources, e.g., both gasoline-powered and electric-powered vehicles. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 schematically shows a charging device of an environmentally friendly vehicle, according to a first exemplary embodiment of the present invention. Fig. 2 is a flowchart schematically showing a first charging process of an environmentally friendly vehicle, according to a first exemplary embodiment of the present invention. Fig. 3 is a flowchart schematically showing a second charging process in a charging device of an environmentally friendly vehicle, according to a first exemplary embodiment of the present invention. Fig. 4 schematically shows a charging device of an environmentally friendly vehicle, according to a first exemplary embodiment of the present invention. Fig. 5 is a flowchart schematically showing a first charging process in a charging device of an environmentally friendly vehicle, according to a first exemplary embodiment of the present invention.Figure 6 is a flowchart which schematically shows a second charging process in a charging device of an environmentally friendly vehicle, according to a first exemplary embodiment of the present invention. The following list of reference symbols is provided for the reader's convenience: 101, 102 first and second motor; 103, 104 first and second inverter; 105, 403 voltage transformer; 106, 404 battery; 200, 500 charging control element; 300, 600 commercial electrical power or energy; 405 relay; 407 rectifier DETAILED DESCRIPTION OF THE EXECUTION FORMS The present invention is described in more detail below with reference to the accompanying drawings, which show exemplary embodiments of the invention. As experts will realize, the described embodiments can be modified in various different ways, all of which do not deviate from the spirit or scope of the present invention. To explain the present invention, parts which are not related to the description are omitted, and the same elements or equivalents are designated by the same reference numerals throughout the specification. The dimensions and thickness of each element are also shown arbitrarily in the drawings; however, the present invention is not necessarily limited to this, and the thickness of the layers, films, build-up areas, regions, etc., has been enlarged in the drawings for clarity. Fig. 1 schematically shows a charging device of an environmentally friendly vehicle, according to a first exemplary embodiment of the present invention. Fig. 1 shows a charging device of an environmentally friendly vehicle, in which two motors are used. With reference to Fig. 1, the first exemplary embodiment of the present invention includes a first motor 101, a second motor 102, a first inverter 103, a second inverter 104, a voltage transformer 105, a battery 106 and a charging control element 200. The first motor 101 is a three-phase AC motor, which is used to start the machine (not shown) and which is operated as a generator while the machine is running. The first motor 101 is operated by a three-phase AC voltage supplied via the first inverter 103 and generates an AC voltage via a torque of the machine to output it to the first inverter 103. The second motor 102 is a three-phase AC motor to rotate a wheel of a vehicle and generates a drive torque via a three-phase AC voltage supplied by the second inverter 104. The second motor 102 is also operated as a generator while the vehicle is in a regenerative braking state to generate a three-phase AC voltage for the second inverter 104. The first motor 101 includes a Y-connection line of the type of a three-phase coil as a stator coil, wherein one side of the U, V, W phase coil forming the three-phase coil is connected to form a neutral point N1, and the other side of it is connected to the arms according to the first inverter 103. The neutral point N1 of the first motor 101 is connected to the commercial electrical power 300, which is input from outside. The second motor 102 includes a Y-connection line of three-phase coil type as a stator coil, with one side of the U, V, W phase coil connected to form a neutral point N2, and the other side of it connected to the arms corresponding to the second inverter 104. The neutral point N2 of the first motor 102 is connected to the commercial electrical power 300, which is input from outside. The first inverter 103 transforms the DC voltage of the battery 106, which is supplied via the voltage transformer 105 to a three-phase AC voltage, accordingly to a PWM control signal, which is supplied by the charging control element 200 in order to supply it to the first motor 101 as a driver voltage. The second inverter 194 transforms the DC voltage of the battery 106, which is supplied via the voltage transformer 105 to a three-phase AC voltage, accordingly to a PWM control signal, which is supplied by the charging control element 200 in order to supply it to the second motor 102 as a driver voltage. The first inverter 103 includes a power switching element which is arranged on a top side and on a bottom side to be connected in series, and includes a U-phase arm (Sau, Sau'), a V-phase arm (Sav, Sav') and a W-phase arm (Saw, Saw'). The second inverter 104 includes a power switching element which is arranged on a top side and on a bottom side to be connected in series and includes a U-phase arm (Sbu, Sbu'), a V-phase arm (Sbv, Sbv') and a W-phase arm (Sbw, Sbw'). The power switching element can include an NPN-type transistor, an IHBT (isolated gate bipolar transistor), and a MOSFET. When the commercial electrical power 300 is input via a plug connection, the first inverter 103 and the second inverter 104 increase or pass on the voltage, which is supplied via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102 according to a PWM control signal supplied by the charging control element 200 to supply it to the voltage transformer 105. The voltage transformer 105, which is a DC / DC converter, increases or reduces the DC voltage supplied by the battery 106 to a predetermined voltage level, corresponding to a PWM control signal supplied by the charging control element 200, for output to the first inverter 103 or the second inverter 104. The voltage transformer 105 also increases or suppresses the DC voltage supplied via the first inverter 103 and the second inverter 104, according to a PWM control signal supplied by the charging control element 200, in order to supply it to the battery 106 as a charging voltage. The voltage transformer 105 is connected to the two terminals of the battery 106 and includes a first power switching element S1 and a second power switching element S2, which are connected in series to a DC terminal capacitor (Cdc), and a smoothing capacitor (Cbc), which smooths a voltage change between terminals of the battery 106. When the external commercial electrical power 300, which is supplied to a neutral point N1 of the first motor 101 and a neutral point N2 of the second motor M102, can be charged into the DC connection capacitor (Vcs), in which a circulating path for the first inverter 103 and the second inverter 104 is formed, according to a control signal supplied by the charging control element 200, the voltage transformer 105 charges the battery 106 by switching the first power switching element S1 and the second power switching element S2. The battery 106 may include at least one of the following: a nickel-hydrogen battery, a lithium-ion rechargeable battery, and a large capacity capacitor as a DC power source to store a high voltage for operating an environmentally friendly vehicle. The battery 106 can also be charged by the external commercial electrical power 300, which is increased or suppressed by the voltage transformer 105. The commercial electrical power 300 can be connected via a plug connection or a connector connection. It is desirable that the commercial electrical power 300 is an AC power, however, the DC power can be used as the power 300 in the present invention. When the commercial electrical power 300 is connected via a plug connection, the charging control element 200 detects an AC voltage (Vin) input via a neutral point N1 of the first motor 101 and a neutral point N2 of the second motor 102, a voltage (Vdc) of a DC terminal capacitor (Cdc) in which a circuit is formed, a voltage (Vbatt) of a battery 106, a voltage (Vbc) of a smoothing capacitor (Cbc) connected to both ends of the battery 106, and a current (IL) of an inductor to determine a charging mode. The charging control element 200 determines a charging control value according to the specified charging mode and determines a PWM control signal to switch the first inverter 103, the second inverter 104 and the voltage transformer 105 to charge the battery 106. The charging control element 200 compares the input voltage (Vin), which is input via the commercial electrical power 300, with the voltage (Vbatt) of the input voltage (Vin), and if it is determined that the input voltage (Vin) exceeds the voltage (Vbatt) of the battery 106, it controls the switching of the voltage transformer 105 to operate as a buck voltage amplifier. Accordingly, the voltage of the DC terminal capacitor (Cdc) is reduced to a predetermined constant voltage by switching the voltage transformer 105, which is operated as a buck voltage amplifier, and the reduced voltage is supplied to the battery 106 to charge it. At this time, the charging control element 200 switches off the switching of the first inverter 103 and the second inverter 104 in order to prevent an unnecessary switching loss of the first inverter 103 and the second inverter 104. The charging control element 200 also compares the input voltage (Vin) of the commercial electrical power 300, which is input with the voltage (Vbatt) of the battery 106, and if the voltage of the battery 106 exceeds the input voltage (Vin), it operates the switching of the first inverter 103 and the second inverter 104 as a voltage amplifier to transform the input voltage (Vin) to a DC voltage, and at the same time to increase it to a constant voltage so that it is stored in a DC terminal capacitor (Cdc) of the voltage transformer 105. In this process, when the phase of the AC voltage (Vin) which is input via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102 is a positive value (Vin> 0), the charging control element 200 passes the electricity through an upper side U-phase arm (Sau), a V-phase arm (Sav) and a W-phase arm (Saw) of a power switching element which forms the first inverter 103, and switches off a power switching element which forms the second inverter 104. Accordingly, a loop of the commercial electrical power 300 is formed to the neutral point N1 of the first motor 101, to the upper side arm of the first inverter 103, to the DC terminal capacitor (Cdc) of the voltage transformer 105, to a free-running diode formed on a lower side arm of the second inverter 104, to the neutral point of the second motor 102, to the commercial electrical power 300. In this process, the AC voltage (Vin), which is input via the neutral point N1 of the first motor 101, is transformed into a DC voltage by the switching operation of the upper-side U-phase arm (Sau), V-phase arm (Sav) and W-phase arm (Saw) of the first inverter 103 and is simultaneously increased to a previously defined constant, which is to be stored in the DC connection capacitor (Cdc) in the voltage transformer 105. Furthermore, if the phase of the AC voltage (Vin) which is input via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102 is a negative value (Vin< 0), the charging control element 200 directs the electricity through a top-side U-phase arm (Sbu), a V-phase arm (Sbv) and a W-phase arm (Sbw) of a power switching element which forms the second inverter 104, and continuously switches off the power switching element which forms the first inverter 103. Accordingly, a circuit of the commercial electrical power 300 is formed to the neutral point N2 of the second motor 102, to an upper side arm of the second inverter 104, to the DC connection capacitor (Cdc) of the voltage transformer 105, to a free-running diode formed on a lower side arm of the first inverter 103, to the neutral point of the first motor 101, to the commercial electrical power 300. In this process, the AC voltage (Vin), which is input via the neutral point N2 of the second motor 102, is transformed into a DC voltage and is simultaneously increased to a predetermined constant voltage by the switching operation of an upper side U-phase arm (Sbu), a V-phase arm (Sbv) and a W-phase arm (Sbw) of the second inverter 104, which is operated as a voltage amplifier, in order to be stored in the DC terminal capacitor (Cdc) of the voltage transformer 105. When the voltage of battery 106 exceeds the input voltage (Vin) and the first inverter 103 and the second inverter 104 are operated as a voltage amplifier, the charging control element 200 only switches on an upper side power switching element S1 of the voltage transformer 105, so that the voltage which is increased by the first inverter 103 and the second inverter 104 is supplied to the battery to charge it. The charging control element 200 also operates the first inverter 104 or the second inverter 104 as a voltage amplifier to increase the input voltage (Vin) according to the phase of the input voltage (Vin), and when the input voltage (Vin) exceeds the battery 106 voltage (Vbatt), the control element 200 operates the voltage transformer 105 as a buck voltage amplifier, so that the input voltage (Vin), which is increased by the first inverter 103 or the second inverter 104, is pushed down to charge the battery 106. The charging control element 200 also operates the first inverter 103 or the second inverter 104 as a voltage amplifier to increase the input voltage (Vin) according to the phase of the input voltage (Vin), and when the battery 106 voltage (Vbatt) exceeds the input voltage (Vin), the charging control element 200 switches off the voltage transformer 105, so that the input voltage (Vin), which is increased by the first inverter 103 or the second inverter 104, is supplied to the battery 106 as a charging voltage. The charging control element 200 uses the commercial electrical power 300 to charge the battery 106 according to the processes or operations above, and when the battery 106 is fully charged, a relay 107 is switched off to cut off the commercial electrical power 300 so that the battery 106 is not overcharged. Fig. 2 is a flowchart which schematically shows a first charging process in a charging device of an environmentally friendly vehicle, according to a first exemplary embodiment of the present invention. With reference to Fig. 2, the environmentally friendly vehicle according to the present invention is in standby (S101), and the charging control element 200 detects whether a plug for charging is connected to the outside of the commercial electrical power 300 (S102). When the charging plug is detected in step S102, it enters a charging mode in step S103, and the charging control element 200 detects a battery 106 voltage (Vbatt) and an input voltage (Vin) of the commercial electrical power 300, which is input via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102, in step S104. And the charging control element 200 compares the battery 106 voltage (Vbatt) with the input voltage (Vin) detected in step S104 and determines whether the input voltage (Vin) entered via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102 exceeds the battery 106 voltage (Vbatt) in step S105. If the input voltage (Vin), which is entered via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102, exceeds the battery 106 voltage (Vbatt) in step S105, the charging control element 200 switches off the first inverter 103 and the second inverter 104, so that the input voltage (Vin) is passed on in step S106. That is, the first inverter 103 and the second inverter 104 are controlled so that they are configured, and the unnecessary switching operation for increasing the voltage does not occur in order to save the switching loss in a state in which a high voltage is applied. In this process, the charging control element 200 controls an upper side power switching element S1 and a lower side power switching element S2, which form the voltage transformer 105, to operate as a buck voltage amplifier, so that the input voltage (Vin), which is input via the first inverter 103 and the second inverter 104, is reduced to a predetermined voltage in step S107, in order to supply it to the battery 106 as a charging voltage in step S113. If it is determined that the battery 106 voltage (Vbatt) exceeds the input voltage (Vin) which is entered via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102 in step S105, the charging control element 200 determines whether the phase of the input voltage (Vin) is a positive value (Vin> 0) in step S108. If the phase of the input voltage (Vin), which has a positive value (Vin> 0) through the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102, is in step S108, the charging control element 200 switches the first inverter 103 via a PWM control signal to convert the input voltage (Vin), which is input via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102, into a DC voltage, and simultaneously performs a voltage amplifier function so that it is increased to a previously defined level in step S109. For example, the charging control element 200 passes the electricity through an upper side U-phase arm (Sau), V-phase arm (Sav) and W-phase arm (Saw) of the power switching element, which forms the first inverter 103, and switches off the power switching element, which forms the second inverter 104. Accordingly, a loop of commercial electrical power 300 is formed to the neutral point N1 of the first motor 101, to an upper side arm of the first inverter 103, to a DC connection capacitor (Cdc) of the voltage transformer 105, to a free-running diode formed on a lower side arm of the second inverter 104, to the neutral point N2 of the second motor 102, to a commercial electrical power 300. In this process, the AC voltage (Vin), which is input via the neutral point N1 of the first motor 101, is transformed into a DC voltage by the switching operation of one upper-side U-phase arm (Sau), one V-phase arm (Sav) and one W-phase arm (Saw) of the first inverter 103, which is operated as a voltage amplifier, and is simultaneously increased to a predetermined voltage and supplied to the voltage transformer 105 to form S111. If the phase of the input voltage (Vin), which is input via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102, has a negative value (Vin< 0) in step S108, the charging control element 200 switches the second inverter 104 via a PWM control signal to convert the input signal (Vin), which is input via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102, into a DC voltage and simultaneously performs a voltage amplifier function to increase it to a previously defined level in step S110. For example, the charging control element 200 directs the electricity via an upper side U-phase arm (Sbu), a V-phase arm (Sbv) and a W-phase arm (Sbw) of the power switching element, which forms the second inverter 104, and maintains the off state of the power switching element, which forms the first inverter 103. Accordingly, a loop of the commercial electrical power 300 is formed to the neutral point of the second motor 102 N2, to an upper side arm of the second inverter 104, to a DC connection capacitor (Cdc) of the voltage transformer 105, to a free-running diode formed on a lower side arm of the first inverter 103, to a neutral point of the first motor 101, to the commercial electrical power 300. In this process, the AC voltage (Vin) which is input via the neutral N2 of the second motor 102 is transformed to a DC voltage by the switching operation of an upper side U-phase arm (Sbu), a V-phase arm (Sbv) and a W-phase arm (Sbw) of the second inverter 104 and is simultaneously increased to a predetermined constant voltage which is supplied to the voltage transformer 105 (S111). Furthermore, the charging control element 200 transforms the AC voltage, which is input via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor M2, into a DC voltage, simultaneously increases the DC voltage to supply it to the voltage transformer 105, and continuously switches on an upper side power switching element S1 of the voltage transformer 105 (S112). Accordingly, the voltage, which is increased by the first inverter 103 and the second inverter 104, is supplied to the battery 106 in order to charge the battery 106 (S113). At this moment, the unnecessary switching operation of the first inverter 103 and the second inverter 104 is not generated on the voltage transformer 105, and therefore no switching loss is formed. The charging control element 200 uses the external commercial electrical power 300 to charge the battery 106 during the above operations, and when it is determined that the battery 106 is fully charged (S114), the relay 107 is switched off to disconnect the commercial electrical power 300 in order to prevent the battery 106 from being overcharged, and the charging process ends (S115). Fig. 3 is a flowchart which schematically shows a second charging process in a charging device of an environmentally friendly vehicle, according to a first exemplary embodiment of the present invention. With reference to Fig. 3, in a standby mode in which the environmentally friendly vehicle is waiting for the battery 106 to be charged (S201), the charging control element 200 determines whether a charging plug which connects the commercial electrical power 300 is plugged in (S202). In step S202, when it is determined that the charging plug is attached, the charging control element 200 enters a charging mode (S203) and detects the input voltage (Vin) of the commercial electrical power 300, which is input via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102, and the voltage (Vbatt) of the battery 106 (S204). The charging control element 200 then determines whether the phase of the input voltage (Vin), which is entered via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102, has a positive value (Vin> 0) (S205). In step S205, when the phase of the input voltage (Vin), which has a positive value (Vin> 0) via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102, the charging control element 200 uses a PWM control signal to perform the switching of the first inverter 103, so that the input voltage (Vin), which is input via the neutral point N1 of the first motor 101, is transformed into a DC voltage and simultaneously increased to a previously defined level (S206). For example, the charging control element 200 directs the electricity via an upper side U-phase arm (Sau), a V-phase arm (Sav) and a W-phase arm (Saw) of a power switching element, which forms the first inverter 103, and maintains the off state of the power switching element, which forms the second inverter 104. Accordingly, a loop of the commercial electrical power 300 is formed to the neutral point N1 of the first motor 101, to an upper side arm of the first inverter 103, to a DC connection capacitor (Cdc) of the voltage transformer 105, to a free-running diode formed on a lower side arm of the second inverter, to the neutral point of the second motor 102, to the commercial electrical power 300. In this process, an AC voltage (Vin), which is input via the neutral point N1 of the first motor 101, is transformed into a DC voltage by the switching operation of an upper side U-phase arm (Sau), a V-phase arm (Sav) and a W-phase arm (Saw) of the first inverter 103, which is operated as a voltage amplifier, and is simultaneously increased to a previously determined uniform voltage, which is to be supplied to the DC connection capacitor (Cdc), which is formed in the voltage transformer 105 (S208). In step S205, when the phase of the input voltage (Vin), which is input via the neutral point N1 of the first motor 101 and the neutral point N2 of the second motor 102, has a negative value (Vin< 0), the charging control element 200 uses a PWM control signal to operate the switching of the second inverter 104 in order to transform the input voltage (Vin), which is input via the neutral point N2 of the second motor 102, into a DC voltage and simultaneously increase it to a previously defined level (S207). For example, the charging control element 200 carries electricity from an upper side U-phase arm (Sbu), a V-phase arm (Sbv) and a W-phase arm (Sbw) of the power switching element that forms the second inverter 104, and maintains the off state of the power switching element that forms the first inverter 103. Accordingly, a loop of the commercial electrical power 300 is formed to the neutral point N2 of the second motor 102, to an upper side arm of the second inverter 104, to a DC terminal capacitor (CCD) of the voltage transformer 105, to a free-running diode formed on a lower side arm of the first inverter 103, to a neutral point of the first motor 101 to the commercial electrical power 300. In this process, the AC voltage (Vin), which is input via the neutral point N2 of the second motor 102, is transformed into a DC voltage by the switching operation of an upper side U-phase arm (Sbu), a V-phase arm (Sbv) and a W-phase arm (Sbw) of the second inverter 104 and is simultaneously increased to a previously determined constant voltage, which is to be supplied to the DC connection capacitor (Cdc) formed in the voltage transformer 105 (S208). As described above, in a state where the input voltage (Vin) is increased by the first inverter 103 and the second inverter 104 to be stored in the DC terminal capacitor (Cdc) formed in the voltage transformer 105, the charging control element determines whether the input voltage (Vin) exceeds the voltage (Vbatt) of the battery 106 (S209). In step S209, when it is determined that the input voltage (Vin) exceeds the voltage (Vbatt) of battery 106, the charging control element 200 controls the switching of an upper-side power switching element S1 and a lower-side power switching element S2, which form the voltage transformer 105, so that they are operated as a buck voltage amplifier, and the charging control element 200 reduces the input voltage (Vin), which is increased by the first inverter 103 and the second inverter 104, back to a predetermined voltage (S210) in order to supply it to battery 106 as a charging voltage (S212). That is, since the input voltage (Vin), which is increased by the first inverter 103 and the second inverter 104, exceeds a nominal voltage for charging the battery 105, the voltage is reduced to the nominal voltage to be supplied to the battery 106. However, if the input voltage (Vin) in step S209 is less than the voltage (Vbatt) of battery 106, the input voltage (Vin), which is increased by the first inverter 103 and the second inverter 104, does not exceed the nominal voltage for charging battery 105, and therefore the control element 200 keeps the voltage transformer 105 in an off state (S211). Accordingly, the input voltage (Vin), which is increased by the first inverter 103 and the second inverter 104, is supplied to the battery 106 stably as a charging voltage, and the switching loss of the voltage transformer 105 is not generated (S212). In a state where the battery 106 can be charged by the commercial electrical power 300, the charging control element 200 determines whether the charging of the battery 106 is complete (S213). When it is determined that the battery 106 is fully charged in step S213, the charging control element 200 switches off the relay 107 to disconnect the input of the commercial electrical power 300 and terminates the charging operation so that the battery 106 is not overcharged (S214). Fig. 4 schematically shows a charging device of an environmentally friendly vehicle according to a first exemplary embodiment of the present invention. Fig. 4 is a drawing showing a charging device of an environmentally friendly vehicle in which an engine is used. With reference to Fig. 4, the exemplary embodiment of the present invention includes a motor 401, an inverter 402, a voltage transformer 403, a battery 404, a relay 405, a rectifier 406 and a charging control element 500. The motor 401 is a three-phase AC type to rotate a wheel and uses a three-phase AC voltage supplied by the inverter 402 to generate a drive torque. Likewise, the motor 401 is operated for the regenerative braking of a vehicle to output a three-phase AC voltage which is transferred to the inverter 402. The motor 401 includes a three-phase coil of the Y-connection line type, as a stator coil, wherein one side of the U, V, W phase coil, which forms a three-phase coil, is connected to form a neutral point N1, and the other side of it is connected to the arms belonging to the inverter 402. The neutral point N1 of the motor 401 is connected to a commercial electrical power 600, which is input from outside. The inverter 402 transforms the DC voltage of the battery 404, which is supplied via the voltage transformer 403, into a three-phase AC voltage corresponding to a PWM control signal, which is supplied by the charging control element 500, in order to supply it to the motor 401 as a driver voltage. When the commercial electrical power 600 is input via a plug connection, the inverter 402 increases or passes on the voltage supplied via the neutral point N of the motor 401, according to a PWM control signal supplied by the charging control element 500 to deliver it to the voltage transformer 403. The inverter 402 includes a power switching element which is arranged on a top side and a bottom side to be connected in series, and includes a U-phase arm (Sbu, Sbu'), a V-phase arm (Sbv, Sbv') and a W-phase arm (Sbw, Sbw'). The power switching element can include an NPN-type transistor, an IGBT (isolated gate bipolar transistor), and a MOSFET. The voltage transformer 403, which is a DC / DC converter, increases the DC voltage supplied by the battery 404 to a predetermined voltage level or reduces it to this level, according to a PWM control signal supplied by the charging control element 500, to output it to the inverter 402. The voltage transformer 403 also increases or decreases the DC voltage supplied by the inverter 402, according to a PWM control signal supplied by the charging control element 500, in order to supply it to the battery 404 as a charging voltage. The voltage transformer 403 is connected to both ends of the battery 404 and includes a first power switching element S1 and a second power switching element S2, which are connected in series to a DC terminal capacitor (Cdc), and a smoothing capacitor (Cbc), which smooths out a voltage variation between both ends of the battery 404. When the external commercial electrical power 600, which is supplied to a neutral point N of the motor M, can be changed in the DC terminal capacitor (Cdc) in which a loop path is formed through the inverter 402, according to a control signal supplied by the charging control element 500, the voltage transformer 403 charges the battery 404 by switching the first power switching element S1 and the second power switching element S2. The battery 404 may contain at least one of the following: a nickel-hydrogen battery, a lithium-ion rechargeable battery, and a large capacity capacitor as a DC power source to store a high voltage for operating an environmentally friendly vehicle. The battery 404 can also be charged by the electrical power supplied by the voltage transformer 403. When the charging of battery 404 is complete, relay 405 is switched by a control signal transmitted by the charging control element 500 to disconnect the input of commercial electrical power 600. The rectifier 406 transforms the AC type of commercial electrical power 600 into a DC voltage to supply it to the neutral point (N) of the motor 401. When the commercial electrical power 600 is connected via a plug, the charging control element 500 detects an AC voltage (Vin) input via a neutral point N of the motor 401, a voltage (Vdc) of a DC connection capacitor (Cdc) in which a loop is formed, a voltage (Vbatt) of a battery 404, a voltage (Vbc) of a smoothing capacitor (Cbc) connected to both ends of the battery 404, and a current (IL) of an inductor to determine a charging mode. The charging control element 500 uses a PWM control signal to switch the inverter 402 and the voltage transformer 403 to charge the battery 404 in a charging mode. When the external voltage is input via the rectifier 406, the charging control element 500 compares the input voltage (Vin) and the battery 404 voltage (Vbatt) and switches off the inverter 402 if the input voltage (Vin) exceeds the battery 404 voltage (Vbatt). Accordingly, the inverter 402 forwards the input voltage (Vin) which is input via a neutral point N of the motor 401, so that the voltage is stored in the DC terminal capacitor (Cdc) of the voltage transformer 403. In this process, the charging control element 500 controls the switching of the voltage transformer 403, which is to be operated as a buck voltage amplifier, so that the voltage stored in the DC connection capacitor (Cdc) is reduced to a nominal voltage, which is to be supplied to the battery 404 as a charging voltage. The charging control element 500 also compares the input voltage (Vin) with the battery 404 voltage (Vbatt), and if the battery 404 voltage exceeds the input voltage (Vin), the control element 500 operates the inverter 402 as a voltage amplifier to increase the input voltage (Vin) and stores the increased voltage in the DC terminal capacitor (Cdc) of the voltage transformer 403. In this process, the charging control element 500 continuously switches on an upper-side power switching element S1 of the voltage transformer 403, so that the voltage, which is increased by the inverter 402, is supplied to the battery 404 stably as a charging voltage. Even when the external voltage, which is rectified by the rectifier 406, is input via the plug, the charging control element 500 operates the inverter 402 as a voltage amplifier to increase the input voltage (Vin), and the increased voltage is stored in the DC terminal capacitor (Cdc) of the voltage transformer 403. Furthermore, the charging control element 500 compares the input voltage (Vin) with the battery 404 voltage (Vbatt), and if the input voltage (Vin) exceeds the battery 404 voltage (Vbatt), the control element 500 controls the switching of the voltage transformer 403 to operate as a buck voltage amplifier, so that the voltage stored in the DC terminal capacitor (Cdc) is reduced to be supplied to the battery 404 as a charging voltage. The charging control element 500 also compares the input voltage (Vin) with the battery 404 voltage (Vbatt), and if the battery 404 voltage exceeds the input voltage (Vin), the charging control element 500 maintains the switched-off state of the voltage transformer 403, so that the voltage, which is increased by the inverter 402, is supplied to the battery 404 as a charging voltage. According to the above processes or operations, the charging control element 500 uses the external commercial electrical power 600 to charge the battery 404, and when the battery 404 is fully charged, the control element 500 switches off the relay 405 to disconnect the input of the commercial electrical power 600 so that the battery 404 is not overcharged. The commercial electrical power 600 can be connected via a plug connection or a connector connection. It is desirable that the commercial electrical power 600 is an AC power, however, the DC power can be used as the power 600 in the present invention. Fig. 5 is a flowchart which schematically shows a first charging process in a charging device of an environmentally friendly vehicle, according to a first exemplary embodiment of the present invention. With reference to Fig. 5, the environmentally friendly vehicle according to the present invention is in standby (S301), and the charging control unit 500 detects whether a plug for charging is connected to the external commercial electrical power 600 (S302). When the commercial electrical power 600 is connected as a plug in step S302, the charging control element 500 enters a charging mode (S303) and detects the battery 404 voltage (Vbatt) and the input voltage (Vin) which is entered via the neutral point (N) of the motor 401, which is transformed into a DC voltage via the rectifier 406 (S304). Furthermore, the charging control unit 500 compares the input voltage (Vin) and the battery 404 voltage, which is detected in step S304, and determines whether the input voltage (Vin) is greater than the battery 404 voltage (Vbatt) (S305). If the input voltage (Vin) exceeds the battery 404 voltage (Vbatt) in step S305, the charging control element 500 switches off the inverter 402 to pass on the input voltage (Vin) so that the voltage is stored in the DC terminal capacitor (Cdc) which is formed in the voltage transformer 403 (S306). That is, since the inverter 402 is controlled or operated in an off state, the switching operation for increasing the voltage is not generated, and the switching loss is not created. In this process, the charging control element 500 controls the switching of an upper-side power switching element S1 and a lower-side power switching element S2, which form the voltage transformer 403, to be operated as a buck voltage amplifier (S307), so that the nominal charging voltage is suppressed in order to be supplied to the battery 404 as a charging voltage (S311). When it is determined that the battery 404 voltage (Vbatt) exceeds the input voltage (Vin) in step S305, the charging control element 500 switches the inverter 402 to operate as a voltage amplifier via a PWM control signal (S308) so that the input voltage (Vin) is increased to a nominal charging voltage (S309). In this process, the voltage, which is increased by the inverter 402, is stored in the DC connection capacitor (Cdc) inside the voltage transformer 403. In addition, the charging control element 500 controls an upper-side power switching element S1 of the voltage transformer 403 to be continuously switched on (S310). Accordingly, the voltage, which is increased by the inverter 402, is supplied to the battery 404 as a charging voltage (S311). In this process, the voltage transformer 402 does not generate any unnecessary switching operation for increasing or decreasing the voltage, and therefore the switching loss does not occur. The charging control element 500 uses the commercial electrical power 600 to charge the battery 404 according to the above operations; when the battery 404 is fully charged (S312), the relay 405 is switched off to disconnect the input of the commercial electrical power 600 so that the battery 404 is not overcharged, and then the charging ends (S313). Fig. 6 is a flowchart which schematically shows a second charging process in a charging device of an environmentally friendly vehicle, according to a first exemplary embodiment of the present invention. With reference to Fig. 5, the environmentally friendly vehicle according to the present invention is in standby (S401), and the charging control unit 500 detects whether a plug for charging is connected to the external commercial electrical power 600 (S402). When the charging plug is detected by the commercial electrical power 600 in step S402, the charging control element 500 enters a charging mode (S403) and detects the battery 404 voltage (Vbatt) and the input voltage (Vin) which is input via the neutral point (N) of the motor 401, which is transformed to a DC voltage via the rectifier 406 (S404). Next, the charging control element 500 switches the inverter 402 to be operated as a voltage amplifier via the PWM control signal switching (S405). Accordingly, the inverter 402 increases the input voltage (Vin), which is transformed to a DC voltage by the rectifier 406 in order to be output through the neutral point (N) of the motor 401, to a predetermined voltage, and stores the voltage in the DC terminal capacitor (Cdc) of the voltage transformer 403 (S406). Furthermore, the charging control unit 500 compares the input voltage (Vin) and the battery 404 voltage, which are detected in step S404, and determines whether the input voltage (Vin) exceeds the battery 404 voltage (Vbatt) (S407). When the input voltage (Vin) exceeds the battery 404 voltage (Vbatt) in step S407, the charging control element 500 controls the switching of an upper-side power switching element S1 and a lower-side switching element S2, which form the voltage transformer 403, to be operated as a buck voltage amplifier (S408). Accordingly, the voltage transformer 403 reduces the input voltage (Vin) to a nominal charging voltage of the battery 404 (S408) in order to supply it to the battery 404 as a charging voltage (S410). When it is determined that the battery 404 voltage (Vbatt) exceeds the input voltage (Vin) in step S407, the charging control element 500 switches off the switching of the voltage transformer 403 (S409). In this process, the output current of the voltage transformer 403 is free-running via an inductor of the voltage transformer 403 and a diode of the bottom-side switch S2. The voltage increased by the inverter for this period is stored in the DC terminal capacitor (Cdc) to be supplied to the battery 404 via a buck voltage amplifier operation of the voltage transformer 403 when the input voltage (Vin) exceeds the battery 404 voltage (Vbatt) (S410). In this process, when the battery 404 voltage (Vbatt) exceeds the input voltage (Vin), the voltage transformer 403 does not generate unnecessary switching operation to increase or decrease the voltage, and therefore the switching loss does not occur. The charging control element 500 uses the external commercial electrical power 600 to charge the battery 404 during the above processes or operations, and when it is determined that the battery 404 is fully charged (S414), the relay 405 is switched off to disconnect from the commercial electrical power 600 in order to avoid overcharging the battery 404, and the charging process ends (S412). While this invention has been described in connection with what are currently considered practical exemplary embodiments, it is to be assumed that the invention is not limited to the published embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements which are within the spirit and scope of the attached claims. Furthermore, the control logic of the present invention can be embedded as computer-readable media on a computer-readable medium, which is executed by a processor, a controller, or the like. Examples of computer-readable media include, but are not limited to, ROM, RAM, compact disc (CD) ROMs, magnetic tapes, floppy disks, flash drives, smart cards, and optical storage devices. The computer-readable recording medium can also be distributed across networked computer systems, so that the computer-readable media are stored and executed in a distributed manner, such as by a telematics server or a controller area network (CAN).

Claims

Charging device comprising: a battery (106) suitable and configured to store DC voltage; first and second motors (101, 102) suitable and configured to operate as a motor or a generator; first and second inverters (103, 104) suitable and configured to operate the first and second motors (101, 102); a voltage transformer (105) suitable and configured to increase the DC voltage of the battery (106) to supply it to the first and second inverters (103, 104) and to increase the DC voltage of the inverter to supply it to the battery (106); and a charging controller (200) suitable and configured to operate the first and second inverters (103, 104) as a booster or generator.to operate voltage amplifiers or to operate the voltage transformer (105) as a step-down converter, according to a voltage which is input via a neutral point of the first and second motors (101, 102) and the voltage of the battery (106), wherein the charging control element (200) is configured to switch off the voltage transformer (105) so that the voltage which is increased by the first inverter (103) or the second inverter (104) charges the battery (106) when the voltage which is input via the neutral point of the first and second motors (101, 102) is less than the battery voltage. Charging device according to claim 1, wherein the charging control element (200) controls the first and second inverters (103, 104) to be switched off and controls the voltage transformer (105) to be a step-down converter when the voltage which is input via the neutral point of the first and second motors (101, 102) exceeds a battery voltage. Charging device according to claim 2, wherein the charging control element (200) forwards the voltage which is input via the neutral point through the first and second motors (101, 102) to the voltage transformer (105) while the first and second inverters (103, 104) are switched off. Charging device according to claim 1, wherein the charging control element (200) switches the first and second inverters (103, 104) according to the input voltage of the neutral point such that the first and second inverters (103, 104) are voltage amplifiers and continuously switches on an upper switching element of the voltage transformer (105) when the battery voltage exceeds the voltage which is input via the neutral point of the first and second motors (101, 102). Charging device according to claim 1, wherein the charging control element (200) controls the voltage transformer (105) to increase the voltage and perform a DC voltage transformation to charge the battery (106) when the input voltage of the neutral point of the first and second motors (101, 102) exceeds a battery voltage. Charging device according to claim 1, wherein the charging control element (200) uses only the first and second inverters (103, 104) to perform the voltage increase and utilizes the DC voltage transformation, so that the increased and the DC-transformed voltage is supplied to the battery (106) as a charging voltage when the input voltage which is applied via the neutral point of the first and second motors (101, 102) is less than the battery voltage. Charging device according to claim 1, wherein the charging control element (200) disconnects the voltage which is applied to the neutral point of the first and second motors (101, 102) when it is determined that the battery (106) is fully charged. Charging device according to claim 4, wherein the charging control element (200) operates the first inverter (103) as a voltage amplifier when the battery voltage exceeds the input voltage of the neutral point of the first and second motors (101, 102) and the phase of the input voltage has a positive value (Vin> 0). Charging device according to claim 4, wherein the charging control element (200) operates the second inverter (104) as a voltage amplifier when the battery voltage exceeds the input voltage of the neutral point of the first and second motors (101, 102) and the phase of the input voltage has a negative value (Vin< 0). Charging method comprising: detecting a connection to a charging plug; detecting a voltage input via a neutral point of the first and second motors (101, 102) and a voltage of a battery (106) when the connection of the charging plug is detected; charging a battery (106) by operating the first and second inverters (103, 104) as voltage amplifiers or by operating a voltage transformer (105) as a step-down converter, depending on a relationship between a voltage input via the neutral point of the first and second motors (101, 102) and a battery voltage;and switching off the voltage transformer (105) so that the voltage increased by the first inverter (103) or the second inverter (104) charges the battery (106) when the voltage applied via the neutral point of the first and second motors (101, 102) is less than the battery voltage. Charging method according to claim 10, wherein the input voltage is increased only by the voltage transformer (105) to charge the battery (106) when the voltage which is input via the neutral point of the first and second motors (101, 102) exceeds the battery voltage. Charging method according to claim 10, wherein the input voltage is increased only by the first and second inverters (103, 104) to charge the battery (106) when the voltage which is input via the neutral point of the first and second motors (101, 102) is less than the battery voltage. Charging method according to claim 11, wherein the first and second inverters (103, 104) maintain an off state and the voltage input via the neutral point of the first and second motors (101, 102) is passed to the voltage transformer (105) when the voltage input via the neutral point of the first and second motors (101, 102) exceeds the battery voltage. Charging method according to claim 12, wherein the first and second inverters (103, 104) are switched depending on the phase of the input voltage, so that the first and second inverters (103, 104) are operated as voltage amplifiers, and an upper switching element of the voltage transformer (105) is controlled to be continuously switched on when the voltage which is input via the neutral point of the first and second motors (101, 102) is lower than the battery voltage. Charging method according to claim 14, wherein in a state where the voltage input via the neutral point of the first and second motors (101, 102) is less than the battery voltage, when the phase of the input voltage is a positive value (Vin> 0), the first inverter (103) is operated as a voltage amplifier and when the phase of the input voltage is a negative value (Vin< 0), the second inverter (104) is operated as a voltage amplifier. A charging method comprising: detecting a charging plug connection; detecting a voltage input via a neutral point of the first and second motors (101, 102) and a battery voltage (106) when the charging plug connection is detected; charging a battery (106) by increasing the input voltage via a voltage transformer (105) when the voltage input via the neutral point of the first and second motors (101, 102) exceeds the battery voltage; charging a battery (106) by increasing the input voltage via first and second inverters (103, 104), depending on the input voltage, when the voltage input via the neutral point of the first and second motors (101, 102) is lower than the battery voltage;and switching off the voltage transformer (105) so that the voltage increased by the first inverter (103) or the second inverter (104) charges the battery (106) when the voltage applied via the neutral point of the first and second motors (101, 102) is less than the battery voltage. Charging method according to claim 16, wherein the first and second inverters (103, 104) are maintained in a switched-off state so that no switching loss occurs while the input voltage is increased by the voltage transformer (105). Charging method according to claim 16, wherein when the first and second inverters (103, 104) increase the input voltage, an upper switching element of the voltage transformer (105) is controlled to be continuously switched on, so that a switching loss of the voltage transformer (105) does not occur. Charging method according to claim 16, wherein, if the voltage input via the neutral point of the first and second motors (101, 102) is less than the battery voltage, if the phase of the input voltage has a positive value (Vin> 0), the first inverter (103) is controlled to increase the input voltage, and if the phase of the input voltage is a negative value (Vin< 0), the second inverter (104) is controlled to increase the input voltage. Charging method comprising: detecting a charging plug connection; detecting a voltage input via a neutral point of the first and second motors (101, 102) and a battery voltage (106) when the charging plug connection is detected; increasing an input voltage by operating a first inverter (103) or a second inverter (104) as a voltage amplifier, depending on a phase of the voltage input via the neutral point of the first and second motors (101, 102); charging a battery (106) by operating a voltage transformer (105) as a step-down converter or to maintain its off state, depending on a relationship between the voltage input via the neutral point of the first and second motors (101, 102) and the battery voltage;and switching off the voltage transformer (105) so that the voltage increased by the first inverter (103) or the second inverter (104) charges the battery (106) when the voltage applied via the neutral point of the first and second motors (101, 102) is less than the battery voltage. Charging method according to claim 20, wherein, if the voltage input via the neutral point of the first and second motors (101, 102) is a positive value (Vin> 0), the first inverter (103) is operated as a voltage amplifier, and if the phase of the input voltage is a negative value (Vin< 0), the second inverter (104) is operated as a voltage amplifier. Charging method according to claim 20, wherein the voltage transformer (105) is controlled to be a step-down converter such that the input voltage, which is increased by the first inverter (103) or the second inverter (104), is pushed down to charge the battery (106) when the voltage which is input via the neutral point of the first and second motors (101, 102) exceeds the battery voltage. Charging method according to claim 20, wherein the voltage transformer (105) is switched off and the voltage increased by the first inverter (103) or the second inverter (104) charges the battery (106) when the voltage applied through the neutral point of the first and second motors (101, 102) is less than the battery voltage. Charging method according to claim 23, wherein the voltage transformer (105) passes the voltage, which is increased by the first inverter (103) or the second inverter (104), to the battery (106) in order to charge the battery (106) when the voltage which is applied via the neutral point of the first and second motors (101, 102) is less than the battery voltage. Charging method comprising: detecting a voltage input via a neutral point of the first and second motors (101, 102) and a battery voltage (106) when a charging plug connection is detected; operating a first inverter (103) as a voltage amplifier when one phase of the voltage input via the neutral point of the first and second motors (101, 102) is a positive value (Vin> 0), and operating a second inverter (104) as a voltage amplifier to increase the voltage when the phase of the voltage is a negative value (Vin< 0);Operating the voltage transformer (105) as a buck converter, such that the input voltage increased by the first inverter (103) or the second inverter (104) is suppressed to charge the battery (106) when the voltage input across the neutral point of the first and second motors (101, 102) exceeds the battery voltage; and switching off the voltage transformer (105) so that the voltage increased by the first inverter (103) or the second inverter (104) charges the battery (106) when the voltage input across the neutral point of the first and second motors (101, 102) is less than the battery voltage. Charging device comprising: a battery (404) suitable and configured to store DC voltage; first and second motors suitable and configured to operate as a motor or a generator; an inverter (402) suitable and configured to operate a motor (401) and to increase a voltage supplied to a plug; a rectifier (406) suitable and configured to smooth an AC voltage supplied via the plug to deliver it to a neutral point of a motor (401);a voltage transformer (403) which is suitable and configured to increase the DC voltage of the battery (404) to supply it to the inverter (402), and to supply the voltage increased by the inverter (402) to the battery (404) as a charging voltage, or to reduce the voltage to supply it to the battery (404) as a charging voltage; a charging control element (500) which is suitable and configured to operate the inverter (402) as a voltage amplifier or to operate the voltage transformer (403) as a step-down converter to supply the battery voltage with a charging voltage, depending on the voltage input to the neutral point of the motor (401) via the connector and the voltage of the battery (404);Switching off the voltage transformer (403) so that the voltage increased by the inverter (402) charges the battery (404) when the voltage applied via the neutral point of the motor (401) is lower than the battery voltage. Charging device according to claim 26, which further comprises a switch which cuts off a commercial voltage supplied to a rectifier (406) via a plug, corresponding to the control signal of the charging control element (500) when it is detected that the charging of the battery (404) is complete. Charging device according to claim 26, wherein the charging control element (500) switches off the inverter (402) to forward the input voltage to the voltage transformer (403) and operates the voltage transformer (403) as a step-down converter to suppress the input voltage when the voltage input via the neutral point of the motor (401) exceeds the battery voltage. Charging device according to claim 26, wherein the charging control element (500) operates the inverter (402) as a voltage amplifier to increase the input voltage and continuously switches on a top-side power switching element of the voltage transformer (403) so that the voltage increased by the inverter (402) is supplied to the battery (404) to charge it when the voltage input via the neutral point of the motor (401) is less than the battery voltage. A charging method comprising: detecting a battery voltage and an input voltage, which is transformed to a DC voltage by a rectifier (406) to be input via a neutral point of a motor (401) when a charging plug is connected; controlling the inverter (402) to be switched off, operating a voltage transformer (403) as a buck converter to suppress the input voltage, and supplying the suppressed voltage to the battery (404) to charge it when the input voltage exceeds the battery voltage; increasing the input voltage by operating the inverter (402) as a voltage amplifier and continuously switching on a top-side power switching element of a voltage transformer (403) to supply a battery (404) with the increased voltage as a charging voltage when the input voltage is less than the battery voltage;Switching off the voltage transformer (403) so that the voltage increased by the inverter (402) charges the battery (404) when the voltage input via the neutral point of the motor (401) is less than the battery voltage; and when charging is complete, preventing the transmission of a commercial voltage to the neutral point. A charging method comprising: detecting a battery voltage and an input voltage, which is transformed to a DC voltage by a rectifier (406) to be input via a neutral point of a motor (401) when a charging plug is connected; increasing the input voltage by operating an inverter (402) as a voltage amplifier; operating the voltage transformer (403) as a buck converter to suppress the input voltage, which is increased by the inverter (402), and supplying the suppressed voltage to the battery (404) to charge it when the input voltage exceeds the battery voltage by comparing the input voltage with the battery voltage; switching off the voltage transformer (403) to supply the increased voltage to the battery (404) as a charging voltage when the input voltage is less than the battery voltage;Switching off the voltage transformer (403) so that the voltage increased by the inverter (402) charges the battery (404) when the voltage input via the neutral point of the motor (401) is less than the battery voltage; and when charging is complete, preventing the transmission of a commercial voltage at the neutral point.

Images