Electric vehicle charging apparatus

Abstract

An electric vehicle charging apparatus according to an embodiment of the present invention includes: a voltage detection unit which detects the voltage of a control pilot (CP) signal in the form of pulse width modulation (PWM) input from the outside; a duty cycle detection unit which detects the duty cycle of the CP signal; and a control unit which controls the voltage detection unit and the duty cycle detection unit and determines a charging state according to the detection value of the voltage detection unit and the detection value of the duty cycle detection unit. The control unit activates the duty cycle detection unit according to the detection value of the voltage detection unit.

Description

Charging device for electric vehicles

[0001] The present invention relates to electric vehicles, and more particularly to charging of electric vehicles.

[0002] Eco-friendly vehicles such as electric vehicles (EVs) or plug-in hybrid electric vehicles (PHEVs) use electric vehicle supply equipment (EVSE) installed at charging stations to charge their batteries.

[0003] To charge an EV, the EV and EVSE communicate via a charging connector connected between them. Once the charging connector is connected, charging begins after signaling is performed between the EVSE and EV.

[0004] The charging connector has a CP (control pilot) pin, through which a CP signal in the form of Pulse Wide Modulation (PWM) is transmitted from the EVSE to the EV. The interaction between the EVSE and the EV can be monitored and controlled through the CP signal, and the charging status can vary depending on the voltage level and duty ratio of the CP signal. Accordingly, the EV charging device detects the voltage level and duty ratio of the CP signal in sleep mode and determines whether to wake up the device based on the detected voltage level and duty ratio. A method for the EV charging device to accurately and efficiently detect the voltage level and duty ratio of the CP signal is required.

[0005] The technical problem to be solved by the present invention is to provide a charging device for charging an electric vehicle (EV).

[0006] The technical problem to be achieved by the present invention is to enable a charging device for charging an electric vehicle to accurately and efficiently detect the voltage magnitude and duty ratio of a CP signal.

[0007] A charging device for an electric vehicle according to one embodiment of the present invention includes a voltage detection unit that detects a voltage of a CP (control pilot) signal in the form of PWM (Pulse Wide Modulation) input from the outside, a duty cycle detection unit that detects a duty cycle of the CP signal, and a control unit that controls the voltage detection unit and the duty cycle detection unit and determines a charging state according to a detection value of the voltage detection unit and a detection value of the duty cycle detection unit, and the control unit activates the duty cycle detection unit according to the detection value of the voltage detection unit.

[0008] In sleep mode, the voltage detection unit is always in operation, the control unit is connected to the duty ratio detection unit, and when the detection value of the voltage detection unit is +8 V to +10 V, the duty ratio detection unit can be activated.

[0009] The control unit may operate in a sleep mode when the activated duty ratio detection unit detects a detection value of 3% or less or 97% or more, and may operate in a wake-up mode when the activated duty ratio detection unit detects a detection value of 3% to 97%.

[0010] The above control unit can operate in wake-up mode when the activated duty ratio detection unit detects a detection value of 100%.

[0011] The above duty cycle detection unit may include a comparator, and the comparator may include a first input terminal for receiving the CP signal, a second input terminal for receiving a reference voltage, a power terminal for receiving power, and an output terminal for outputting a comparison result of the CP signal and the reference voltage.

[0012] The above duty cycle detection unit may further include a comparator driving unit that drives the comparator.

[0013] The above comparator driving unit is connected to the control unit, and when the detection value of the voltage detection unit is +8 V to +10 V, the control unit can control the comparator driving unit to supply power to the comparator through the power terminal.

[0014] The above comparator driving unit includes a dual bias register transistor, and when the detection value of the voltage detection unit is +8 V to +10 V, the dual bias register transistor can be conducted.

[0015] The above comparator may further include a voltage dividing resistor connected to the first input terminal.

[0016] The voltage detection unit may include a voltage distribution resistor unit and an OP Amp connected to the voltage distribution resistor unit.

[0017] A charging control method of a charging device for an electric vehicle according to an embodiment of the present invention includes the steps of receiving a CP (control pilot) signal in the form of a PWM (Pulse Wide Modulation) input from the outside, the step of detecting a voltage of the CP signal, the step of detecting a duty ratio of the CP signal based on a detected value of the voltage of the CP signal, and the step of determining a charging state based on the detected value of the voltage of the CP signal and the detected value of the duty ratio of the CP signal.

[0018] If the detection value of the voltage of the CP signal is +8 V to +10 V, a step of detecting the duty ratio of the CP signal can be performed.

[0019] In the step of determining the charging state, if the duty ratio of the CP signal is 3% or less or 97% or more, the charging state may be determined to be a sleep mode, and if the duty ratio of the CP signal is 3% to 97%, the charging state may be determined to be an active mode.

[0020] According to an embodiment of the present invention, an EV charging device can efficiently detect the voltage magnitude and duty ratio of a CP signal. According to an embodiment of the present invention, the voltage magnitude and duty ratio of a CP signal can be quickly and accurately detected while minimizing the current consumption of an EV charging device in sleep mode.

[0021] FIGS. 1 and 2 are drawings showing a charging system for an electric vehicle according to one embodiment of the present invention.

[0022] Figures 3 and 4 are examples of electrical equivalent circuits for charging between an EVSE and an EV.

[0023] Figure 5 shows a CP signal in PWM form output by EVSE.

[0024] FIG. 6 is a block diagram of a charging device for an EV according to one embodiment of the present invention, and FIG. 7 is a flowchart of a control method for a charging device for an EV according to one embodiment of the present invention.

[0025] FIG. 8 is a block diagram centered on a duty ratio detection unit of a charging device for an electric vehicle according to an embodiment of the present invention.

[0026] FIG. 9 is an example of a circuit diagram of a charging device for an electric vehicle according to an embodiment of the present invention. FIG. 8 is an example of a circuit diagram of a charging device for an electric vehicle according to an embodiment of the present invention.

[0027] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0028] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0029] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0030] Additionally, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0031] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0032] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

[0033] These terms are intended only to distinguish one component from another, and are not intended to limit the nature, order, or sequence of the component.

[0034] And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, it may include not only cases where the component is directly connected, coupled or connected to the other component, but also cases where the component is 'connected', 'coupled' or 'connected' by another component between the component and the other component.

[0035] Additionally, when described as being formed or arranged "above or below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below", it can include the meaning of a downward direction as well as an upward direction based on one component.

[0036] Hereinafter, embodiments will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or corresponding components are given the same reference numbers, and redundant descriptions thereof will be omitted.

[0037] FIGS. 1 and 2 are drawings showing a charging system for an electric vehicle according to one embodiment of the present invention.

[0038] Referring to FIGS. 1 and 2, an electric vehicle (EV) 10 can be charged from an electric vehicle supply equipment (EVSE) 20. In this specification, an EV (10) refers to a vehicle propelled by an electric motor that draws current from a rechargeable storage battery or other portable energy storage device. Although this specification focuses on an EV (10), it is self-evident that the description can also be applied to a plug-in hybrid electric road vehicle (PHEV).

[0039] For this purpose, a charging cable (22) connected to the EVSE (20) can be connected to the inlet of the EV (10). Here, the EVSE (20) is a facility that supplies AC or DC, and can be placed at a charging station, placed in a home, or implemented to be portable. The EVSE (20) can be used interchangeably with a charging station (supply), an AC charging station (AC supply), a DC charging station (DC supply), a socket-outlet, etc.

[0040] A charging device (Electric Vehicle Charging Controller, EVCC, 100) is mounted within the EV (10) and connected to the EV (10). For example, the charging device (100) may be installed within the trunk of the EV (10), but is not limited thereto.

[0041] Here, the charging device (100) can communicate with the EV (10) and EVSE (20), respectively.

[0042] The method of connecting the EV (10) to the EVSE (20) can be divided into four modes and three cases. Mode 1 is to connect the EV (10) to the AC supply network using a cable and a plug, which is connected to a standard socket outlet. Mode 2 is to connect the EV (10) to the AC supply network using a cable and a plug connected to a standard socket outlet, which has a protection system and CP function to prevent electric shock between the EV and the socket outlet. Mode 3 is to connect the EV (10) using an EVSE (20) permanently connected to the AC supply network, and the CP function is extended to control the devices within the EVSE (20). Mode 4 is to connect the EV (10) to the AC or DC supply network using a dc EVSE or a dc EV charging station using the CP function. Case A is to connect the EV (10) to the AC supply using a cable and plug assembly permanently attached to the EV. Case B connects the EV (10) to the supply using a detachable cable assembly at both ends. Case C connects the EV (10) to the supply using a supply cable and vehicle connector permanently attached to the EV charging station.

[0043] A cable assembly between an EV (10) and an EVSE (20) may be provided with a CP conductor, which is an insulated conductor that creates a CP circuit, together with a PE (protective conductor). Here, the CP circuit is a circuit designed for signal transmission or communication between the EV (10) and the EVSE (20), and the CP function may be used to monitor and control the interaction between the EV (10) and the EVSE (20). A CPF controller (control pilot function controller), which is a device that manages the CP signal and the CP function, may be provided in the EVSE (20). The proximity function may be an electrical or mechanical means that indicates a state in which a connector is inserted into an inlet of an EV (10), or a state in which a plug is inserted into a socket outlet at a charging station.

[0044] In Mode 2, Mode 3 and Mode 4, the EVSE (20) has the function of checking continuous continuity of the protective earthing conductor, verifying that the EV (10) is properly connected to the EVSE (20), supplying power to the EV (10), cutting off power supplied to the EV (10), and transmitting maximum current information. Here, in order to supply power to the EV (10), the CP function between the EVSE (20) and the EV (10) must be accurately set to a signal state that allows power supply.

[0045] In mode 2, mode 3 and mode 4, the CP function is performed through a CP circuit using PWM (pulse wide modulation).

[0046] Figures 3 and 4 are examples of electrical equivalent circuits for charging between an EVSE and an EV.

[0047] Referring to FIGS. 3 and 4, the EVSE (20) includes an oscillator that generates an AC voltage for charging, and the EV (10) includes a resistor and a switch. Here, Va is a pilot wire voltage measured at the output terminal of the EVSE (20), Vg is an internal voltage of the oscillator, and Vb is a voltage, duty cycle, and frequency measured by the EV (10). The EVSE (20) communicates by setting the duty cycle of a PWM signal or a continuous DC voltage signal. The EVSE (20) can change the duty cycle of the PWM signal. The EV (10) responds by applying a resistive load to the positive half-wave of the CP circuit. If the EV (10) draws a current higher than the CP function (duty cycle), the EVSE (20) can open its switching device. At this time, the EVSE (20) will follow the conditions for the allowed response time of the EV (10), the current tolerance with respect to the duty ratio generated by the EVSE (20), and the tolerance of the current measurement in the EVSE (20) itself. The amount of voltage charged to the battery can be controlled by turning on and off the switch connected to the resistor on the EV (10) side.

[0048] Figure 5 shows a CP signal in PWM form output by EVSE.

[0049] Referring to Fig. 5, the EVSE (20) outputs a CP signal in the form of a PWM having a maximum voltage of +12 V and a minimum voltage of -12 V. The charging device (100) of the EV (10) detects the duty ratio and voltage size of the CP signal to monitor and control the charging status.

[0050] The states according to the CP signal can be divided into state A, state B, state C, state D, state E, and state F. State A means a state in which the charger is not connected between the EVSE (20) and the EV (10), that is, an unplugged state, and the peak of the CP signal in state A is +12 V ± 1 V. State B means a state in which the charger is connected between the EVSE (20) and the EV (10), that is, a plugged state, and may mean a charging preparation state. When the maximum voltage of the CP signal is +9 V ± 1 V and the minimum voltage is -12 V ± 1 V, it is determined to be state B. State C and state D mean a charging state, that is, a charging state, and in particular, state D may mean a ventilation-required state during charging. When the maximum voltage of the CP signal is +6V±1V and the minimum voltage is -12V±1V, it is determined to be in the C state, and when the maximum voltage of the CP signal is +3V±1V and the minimum voltage is -12V±1V, it is determined to be in the D state. The E state and the F state may indicate error states. For example, the E state may indicate a state in which power is not supplied to the EVSE (20), and the F state may indicate a state in which the EVSE (20) is unavailable. When the maximum voltage of the CP signal is +0V±1V and the minimum voltage is -12V±1V, it is determined to be in the E state, and when the maximum voltage of the CP signal is -12V±1V and the minimum voltage is -12V±1V, it is determined to be in the F state.

[0051] Meanwhile, the sleep mode is a mode for energy saving, and the charging device (100) of the EV (10) and the EVSE (20) can enter the sleep mode after negotiating a pause through the HLC protocol. On the EVSE (20) side, the sleep mode means that the oscillator is turned off, the +12 V supply of the pilot line is maintained, and the power of the lower layer communication module is turned off. On the EV (10) side, the sleep mode means the B state, and the power of the lower layer communication module can be turned off. The wake-up mechanism may also be used after the charging session has already ended so that the counterpart station can reset the HLC.

[0052] Interaction between EVSE (20) and EV (10) can be monitored and controlled through CP signal, and the charging state can vary depending on the voltage size and duty ratio of the CP signal.

[0053] Table 1 shows the maximum current drawn by the EV (10) for each duty cycle detected by the charging device (100) of the EV (10).

[0054] Nominal duty cycle interpretation by vehicleMaximum current to be drawn by vehicleDuty cycle<3%Charging not allowed3%≤duty cycle≤7%Indicates that digital communication will be used to control an off-board DC charger or communicate available line current for an on-board charger. Digital communication may also be used with other duty cycles.Charging is not allowed without digital communication.5% duty cycle shall be used if the pilot function wire is used for digital communication7%<duty cycle<8%Charging not allowed8%≤duty cycle<10%6A10%≤duty cycle≤85%Available current=(% duty cycle)x0,6A85%<duty cycle≤96%Available current=(% duty cycle-64)x2,5A96%<duty cycle≤97%80ADuty cycle>97%Charging not allowedIf the PWM signal is between 8% and 97%, the maximum current may not exceed the values indicated by the PWM even if the digital signal indicates a higher current.

[0055] The charging device (100) of the EV (10) detects the voltage magnitude and duty ratio of the CP signal when connected to the EVSE (20) to determine whether to operate in sleep mode or wake-up mode. For example, when the voltage magnitude of the CP signal is 9 V ± 1 V and the duty ratio is less than 3% or more than 97%, the charging device (100) operates in sleep mode, when the duty ratio is 3% or more and 97% or less, the charging device (100) operates in wake-up mode, and when a CP signal with a duty ratio of 100% is input in sleep mode, the charging device (100) operates in wake-up mode. In this specification, the sleep mode may be used interchangeably with the standby mode, and the wake-up mode may be used interchangeably with the active mode.

[0056] In this way, whether the charging device (100) is in sleep mode or wake-up mode is determined by considering both the voltage magnitude and duty ratio of the CP signal. However, if the charging device (100) of the EV (10) constantly detects both the voltage magnitude and duty ratio of the CP signal in sleep mode, there is a problem that the current consumption of the charging device (100) of the EV (10) is high.

[0057] According to an embodiment of the present invention, it is intended to accurately detect the voltage magnitude and duty ratio of a CP signal while minimizing the current consumption of a charging device for charging an electric vehicle.

[0058] FIG. 6 is a block diagram of a charging device for an EV according to one embodiment of the present invention, and FIG. 7 is a flowchart of a control method for a charging device for an EV according to one embodiment of the present invention.

[0059] Referring to FIG. 6, a charging device (100) of an EV (10) can be mounted on the EV (10). The charging device (100) includes a connection unit (110), a voltage detection unit (120), a duty ratio detection unit (130), and a control unit (140). Since the embodiment of the present invention relates to a method and device for detecting a CP signal, for the convenience of explanation, the description will focus on the CP signal detection of the charging device (100). Except for the CP signal detection, known technologies related to the charging device (100) can be applied to other contents.

[0060] The control unit (140) generates a control signal for charging between the EV (10) and the EVSE (20). The control signal for charging generated by the control unit (140) can be transmitted to the EVSE (20) through the connection unit (110) or to the ECU (12) in the EV (10). To this end, the control unit (140) controls the voltage detection unit (120) and the duty ratio detection unit (130), and determines the charging status based on the detection value of the voltage detection unit (120) and the detection value of the duty ratio detection unit (130).

[0061] The connection unit (110) is connected to the EVSE (20) and transmits signals between the control unit (140) and the EVSE (20). For example, the connection unit (110) may transmit a charging-related signal received from the EVSE (20) to the control unit (140) and transmit a control signal for charging generated by the control unit (140) to the EVSE (20). In addition, the connection unit (110) transmits power received from the EVSE (20) to the battery (14) in the EV (10) according to the control signal for charging generated by the control unit (140).

[0062] Referring to FIGS. 6 and 7, the connection unit (110) receives a CP (Control Pilot) signal in the form of PWM (Pulse Wide Modulation) from the EVSE (20) (S700). Here, the CP signal is a PWM signal having a predetermined duty cycle, and may be in the form exemplified in FIG. 5. The CP signal is a signal for monitoring and controlling the interaction between the EV (10) and the EVSE (20).

[0063] The voltage detection unit (120) detects the voltage of the CP signal (S710). Here, the voltage may be the maximum voltage of the CP signal in PWM form. Here, the maximum voltage of the CP signal may be used interchangeably with the positive voltage peak. For this purpose, the voltage detection unit (120) may include a positive voltage detection circuit. Alternatively, the voltage may be the maximum voltage and minimum voltage of the CP signal in PWM form. Here, the minimum voltage may be used interchangeably with the negative voltage peak. For this purpose, the voltage detection unit (120) may include a positive voltage detection circuit and a negative voltage detection circuit. Alternatively, the voltage detection unit (120) may include a positive voltage detection circuit and an amplitude detection circuit, and may calculate the minimum voltage using the maximum voltage detected by the positive voltage detection circuit and the amplitude detected by the amplitude detection circuit. For example, if the positive voltage peak of the CP signal is +9 V and the negative voltage peak is -12 V, the voltage detection unit (120) detects that the maximum voltage of the CP signal is +9 V, and as a result of detecting that the amplitude of the CP signal is +21 V (=+9 V - (-12 V)), it can also calculate that the minimum voltage is -12 V (=+9 V - (+21 V)).

[0064] Next, the control unit (140) activates the duty ratio detection unit (130) according to the detected voltage value in step S710 (S720). For example, if the detected voltage value in step S710 is +9 V ± 1 V, i.e., +8 V to +10 V, the control unit (140) can activate the duty ratio detection unit (130). To this end, in the sleep mode, the voltage detection unit (120) is always in operation, and the control unit (140) is connected to the voltage detection unit (120) and the duty ratio detection unit (130), respectively, and activates the duty ratio detection unit (130) according to the detected value of the voltage detection unit (120).

[0065] Next, the duty ratio detection unit (130) detects the duty ratio of the CP signal (S730). The duty ratio detection unit (130) is activated when the detected voltage value of the CP signal in the sleep mode is +9 V ± 1 V, i.e., +8 V to +10 V, and detects the duty ratio of the CP signal. That is, step S730 can be performed when the detected voltage value of the CP signal is +9 V ± 1 V, i.e., +8 V to +10 V. The duty ratio of the CP signal means the ratio of the time that the CP signal is turned on within one cycle in the PWM form.

[0066] Next, the control unit (140) determines the charging state according to the detected value of the voltage of the CP signal detected by the voltage detection unit (120) and the detected value of the duty ratio of the CP signal detected by the duty ratio detection unit (130) (S740). At this time, the control unit (140) can determine that the sleep mode is in case the detected value of the voltage of the CP signal is +9V±1V, that is, +8V to +10V, and the duty ratio of the CP signal is 3% or less or 97% or more, and that the wake-up mode is in case the detected value of the voltage of the CP signal is +9V±1V, that is, +8V to +10V, and the duty ratio of the CP signal is 3% to 97%. In addition, the control unit (140) can determine that the sleep mode is in case the detected value of the voltage of the CP signal is +9V±1V, that is, +8V to +10V, and the duty ratio is 100%.

[0067] Below, the operating principle of the duty cycle detection unit is explained in more detail.

[0068] FIG. 8 is a block diagram centered on a duty ratio detection unit of a charging device for an electric vehicle according to an embodiment of the present invention, and FIG. 9 is an example of a circuit diagram of a charging device for an electric vehicle according to an embodiment of the present invention.

[0069] Referring to FIGS. 8 and 9, a charging device (100) for charging an electric vehicle (10) includes a connection unit (110), a voltage detection unit (120), a duty ratio detection unit (130), and a control unit (140). The charging device (100) may further include a filter (150) and a protection unit (160) disposed between the EVSE (20) and the voltage detection unit (120) and the duty ratio detection unit (130). Here, the filter (150) may have a function of blocking external noise. The protection unit (160) may include a surge protection element. The connection unit (110) of the charging device (100) is connected to an external EVSE (20) and receives a CP signal of a PWM waveform from the EVSE (20). The voltage detection unit (120) detects the voltage of the CP signal, and the duty ratio detection unit (130) detects the duty ratio of the CP signal.

[0070] According to an embodiment of the present invention, the voltage detection unit (120) of the charging device (100) is always in operation even in sleep mode, and the duty ratio detection unit (130) is activated according to the detection value of the voltage detection unit (120). That is, the duty ratio detection unit (130) is not always in operation in sleep mode, and is driven by the control unit (140) only when the detection value of the voltage detection unit (120) satisfies a predetermined range.

[0071] According to an embodiment of the present invention, the voltage detection unit (120) of the charging device (100) always operates in a sleep mode and detects the voltage of the CP signal. To this end, the voltage detection unit (120) may include a voltage-dividing resistor unit and an operational amplifier (OP Amp). Here, the voltage-dividing resistor unit may be arranged between the first node (N1) of the CP line and the OP Amp to distribute the voltage input to the OP Amp. For example, the voltage-dividing resistor unit may include a first resistor (Ra) and a second resistor (Rb), one end of the first resistor (Ra) may be connected to the first node (N1) of the CP line, and the other end of the first resistor (Ra) may be connected to one end of the second resistor (Rb) and the OP Amp. Accordingly, since the voltage input to the OP Amp can be lowered below 12 V, the burden on the OP Amp can be reduced.

[0072] Meanwhile, according to an embodiment of the present invention, the duty ratio detection unit (130) of the charging device (100) includes a comparator (131). The comparator (131) includes a first input terminal (In+) for receiving a CP signal of a PWM waveform, a second input terminal (In-) for receiving a reference voltage, a power terminal (V+ / V-) for supplying power, and an output terminal (Out) for outputting a comparison result between the CP signal and the reference voltage. The duty ratio detection unit (130) may also include a voltage distribution resistor. Here, the voltage distribution resistor may be arranged between the first node (N1) of the CP line and the first input terminal (In+) of the comparator (131) to distribute the voltage input to the first input terminal (In+) of the comparator (131). For example, the resistor unit for voltage distribution includes a third resistor (Rc) and a fourth resistor (Rd), one end of the third resistor (Rc) is connected to a first node (N1) of the CP line, and the other end of the third resistor (Rc) can be connected to one end of the fourth resistor (Rd) and a first input terminal (In+) of the comparator (131). Accordingly, since the voltage input to the comparator (131) can be lowered to less than 12 V, the burden on the comparator (131) can be reduced.

[0073] According to an embodiment of the present invention, if the voltage of the CP signal of the PWM waveform input through the first input terminal (In+) is greater than the reference voltage input through the second input terminal (In-), the output terminal (Out) can output a high signal, and if the voltage of the CP signal of the PWM waveform input through the first input terminal (In+) is less than the reference voltage input through the second input terminal (In-), the output terminal (Out) can output a low signal. The output terminal (Out) of the comparator (131) is connected to the control unit (140), and the control unit (140) calculates the duty ratio using the signal output through the output terminal (Out) of the comparator (131). In this way, when the comparator (131) is used to calculate the duty ratio, ideally, the input impedance of the comparator (131) is infinite, so it is possible to obtain an accurate comparison result without affecting the peripheral circuit.

[0074] At this time, the comparator (131) is driven using power supplied through the power terminal (V+ / V-).

[0075] Meanwhile, according to an embodiment of the present invention, the detected voltage value of the CP signal detected by the voltage detection unit (120) is input to the control unit (140). When the detected voltage value of the CP signal detected by the voltage detection unit (120) is +9 V ± 1 V, i.e., +8 V to +10 V, the control unit (140) activates the duty ratio detection unit (130).

[0076] To this end, according to an embodiment of the present invention, the duty cycle detection unit (130) further includes a comparator driving unit (132) that drives a comparator (131).

[0077] The comparator driving unit (132) is connected to the control unit (140), and when the voltage detection value of the CP signal detected by the voltage detection unit (120) in the sleep mode is +8 V to +10 V, the control unit (140) supplies power to the power terminal (V+ / V-) of the comparator (131) so that the comparator driving unit (132) drives the comparator (131).

[0078] According to an embodiment of the present invention, the comparator driving unit (132) may include a switching unit and a power source (Vd). When the detected voltage value of the CP signal detected by the voltage detection unit (120) in the sleep mode is +8 V to +10 V, the control unit (140) causes the switching unit of the comparator driving unit (132) to conduct, so that the power source (Vd) can supply power to the power terminals (V+ / V-) of the comparator (131). For example, the switching unit of the comparator driving unit (132) may include dual bias resistor transistors (Q1, Q2). The dual bias resistor transistors (Q1, Q2) are NPN / PNP silicon surface-mount transistors having a monolithic bias resistor network. The BRT (bias resistor transistor) includes a single transistor having a monolithic bias network consisting of a base-connected resistor and a base-emitter resistor. The dual bias resistor transistors (Q1, Q2) include two complementary BRT devices. When the detected voltage value of the CP signal detected by the voltage detection unit (120) in the sleep mode is +8 V to +10 V, the control unit (140) can apply power to Ve of the comparator driving unit (132) to conduct the dual bias resistor transistors (Q1, Q2). Accordingly, the power source (Vd) can supply power to the power terminals (V+ / V-) of the comparator (131).

[0079] In this way, the duty ratio detection unit (130) can perform the duty ratio detection operation of the CP signal only when the voltage detection value of the CP signal detected by the voltage detection unit (120) in the sleep mode is between +8 V and +10 V. Accordingly, since the duty ratio detection unit (130) does not operate constantly, the current consumption of the charging device (100) can be reduced.

[0080] If the value detected after the duty cycle detection unit (130) is activated is less than 3% or more than 97%, the duty cycle detection unit (130) is deactivated or disabled again, and can be activated again depending on the detected value of the voltage detection unit (120).

[0081] Here, although one control unit (140) is illustrated as being connected to the voltage detection unit (120) and the duty ratio detection unit (130), it is not limited thereto. The sub-MCU that receives the detection value of the voltage detection unit (120), the sub-MCU that activates the comparator driving unit (132) of the duty ratio detection unit (130), and the sub-MCU that receives the detection value of the duty ratio detection unit (130) may each be implemented independently.

[0082] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

[0083] [Explanation of symbols]

[0084] 10: Electric cars

[0085] 20: Electric vehicle charging facilities

[0086] 22: Charging cable

[0087] 100: Charging device

[0088] 110: Connector

[0089] 120: Voltage detection unit

[0090] 130: Duty cycle detection unit

[0091] 140: Control Unit

Claims

1. In a charging device for an electric vehicle, A voltage detection unit that detects the voltage of a CP (control pilot) signal in the form of PWM (Pulse Wide Modulation) input from the outside. A duty cycle detection unit that detects the duty cycle of the CP signal, and It includes a control unit that controls the voltage detection unit and the duty ratio detection unit, and determines the charging state according to the detection value of the voltage detection unit and the detection value of the duty ratio detection unit. A charging device in which the control unit activates the duty ratio detection unit according to the detection value of the voltage detection unit.

2. In paragraph 1, In sleep mode, the voltage detection unit is always in operation, The above control unit is connected to the duty ratio detection unit, A charging device that activates the duty ratio detection unit when the detection value of the voltage detection unit is +8 V to +10 V.

3. In paragraph 2, A charging device in which the control unit operates in a sleep mode when the activated duty ratio detection unit detects a detection value of 3% or less or 97% or more, and operates in a wake-up mode when the activated duty ratio detection unit detects a detection value of 3% to 97%.

4. In paragraph 3, The above control unit is a charging device that operates in wake-up mode when the activated duty ratio detection unit detects a detection value of 100%.

5. In paragraph 2, The above duty cycle detection unit includes a comparator, A charging device comprising a first input terminal for receiving the CP signal, a second input terminal for receiving a reference voltage, a power terminal for receiving power, and an output terminal for outputting a comparison result of the CP signal and the reference voltage.

6. In paragraph 5, A charging device wherein the duty ratio detection unit further includes a comparator driving unit that drives the comparator.

7. In paragraph 6, The above comparator driving unit is connected to the above control unit, A charging device in which, when the detection value of the voltage detection unit is +8 V to +10 V, the control unit controls the comparator driving unit to supply power to the comparator through the power terminal.

8. In paragraph 7, A charging device in which the comparator driving unit includes a dual bias register transistor, and the dual bias register transistor is turned on when the detection value of the voltage detection unit is +8 V to +10 V.

9. In paragraph 5, A charging device wherein the comparator further includes a voltage dividing resistor connected to the first input terminal.

10. In paragraph 1, A charging device including a voltage detection unit, a voltage distribution resistor unit, and an OP Amp connected to the voltage distribution resistor unit.

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