Electric vehicle charging apparatus

Abstract

An electric vehicle charging apparatus according to an embodiment of the present invention includes: a connection unit for receiving a pulse wide modulation (PWM) type control pilot (CP) signal; a first voltage detection unit for detecting a first voltage of the CP signal; a second voltage detection unit for detecting a second voltage of the CP signal; a control unit for calculating a third voltage which is a difference between the first voltage and the second voltage, and determines the charging state of the charging apparatus by using the detected first voltage and the calculated third voltage, wherein the first voltage is the maximum voltage of the CP signal, the second voltage is the difference between the maximum voltage and the minimum voltage of the CP signal, and the third voltage is the minimum voltage of the CP signal.

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 features a CP (control pilot) pin, through which a PWM (Pulse Wide Modulation) CP signal is transmitted from the EVSE to the EV. The interaction between the EVSE and the EV can be monitored and controlled through this CP signal, and the voltage level of the CP signal can vary depending on the charging state. Accordingly, the EV's charging device must detect the voltage level of the CP signal. A method for accurately and efficiently detecting the voltage level of the CP signal is needed.

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

[0006] According to one embodiment of the present invention, a charging device for an electric vehicle includes a connection unit for receiving a CP (Control Pilot) signal in the form of PWM (Pulse Wide Modulation), a first voltage detection unit for detecting a first voltage of the CP signal, a second voltage detection unit for detecting a second voltage of the CP signal, a control unit for calculating a third voltage which is a difference between the first voltage and the second voltage, and determining a charging state of the charging device using the detected first voltage and the calculated third voltage, wherein the first voltage is a maximum voltage of the CP signal, the second voltage is a difference between a maximum voltage and a minimum voltage of the CP signal, and the third voltage is a minimum voltage of the CP signal.

[0007] The charging status of the above charging device may be one of a charger not connected state, a charger connected state, a charging state, and an error state.

[0008] If the first voltage detected by the first voltage detection unit is +11 V to +13 V and the second voltage detected by the second voltage detection unit is +23 V to +25 V, it is determined that the charger is not connected, if the first voltage detected by the first voltage detection unit is +8 V to +10 V and the second voltage detected by the second voltage detection unit is +20 V to +22 V, it is determined that the charger is connected, if the first voltage detected by the first voltage detection unit is +5 V to +7 V and the second voltage detected by the second voltage detection unit is +17 V to +19 V, or if the first voltage detected by the first voltage detection unit is +2 V to +4 V and the second voltage detected by the second voltage detection unit is +14 V to +16 V, it is determined that the charging state, and if the first voltage detected by the first voltage detection unit is -1 V to +1 V and the second voltage detected by the second voltage detection unit is +11 V to If the first voltage detected by the first voltage detection unit is +13V or the first voltage detected by the first voltage detection unit is -13V to -11V and the second voltage detected by the second voltage detection unit is -1V to +1V, it can be determined as an error state.

[0009] The second voltage detection unit may include a first capacitor having one end connected to a first node between the connection unit and the first voltage detection unit, a first diode having one end connected to the other end of the first capacitor and the other end connected to ground, a second diode having one end connected to one end of the first diode, and a second capacitor having one end connected to the other end of the second diode and the other end connected to ground.

[0010] The second voltage detection unit may further include a resistor connected between the other end of the second diode and one end of the second capacitor.

[0011] The first voltage detection unit may include a third diode having one end connected to the first node and a third capacitor having one end connected to the other end of the third diode and the other end connected to ground.

[0012] The second node between the second diode and the second capacitor of the second voltage detection unit and the third node between the third diode and the third capacitor of the first voltage detection unit may each be connected to the control unit.

[0013] It may further include a filter unit disposed between the above connecting unit and the first node.

[0014] A method for controlling a charging device of an electric vehicle according to one embodiment of the present invention includes the steps of receiving a CP (Control Pilot) signal in a PWM (Pulse Wide Modulation) form, detecting a first voltage of the CP signal, detecting a second voltage of the CP signal, calculating a third voltage which is a difference between the first voltage and the second voltage, and determining a charging state of the charging device using the detected first voltage and the calculated third voltage, wherein the first voltage is a maximum voltage of the CP signal, the second voltage is a difference between a maximum voltage and a minimum voltage of the CP signal, and the third voltage is a minimum voltage of the CP signal.

[0015] According to an embodiment of the present invention, the voltage level of a CP signal between an EVSE and an EV can be efficiently detected. According to an embodiment of the present invention, a circuit for detecting the voltage level of a CP signal within a charging device of an EV can be implemented in a simple, inexpensive manner while maintaining accurate performance.

[0016] Figures 1 and 2 are drawings showing a charging system for an electric vehicle according to one embodiment of the present invention.

[0017] Figures 3 and 4 illustrate electrical equivalent circuits of a CP circuit.

[0018] Figure 5 shows a CP signal in PWM form output by EVSE.

[0019] FIG. 6 is a block diagram of a charging device for an EV according to one embodiment of the present invention.

[0020] Figure 7 is a flowchart of a control method of a charging device of an EV according to one embodiment of the present invention.

[0021] Figure 8 is a CP signal detection circuit according to one embodiment of the present invention.

[0022] Figures 9 to 13 are simulation results when various CP signals are input to a circuit according to an embodiment of the present invention.

[0023] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] Figures 1 and 2 are drawings showing a charging system for an electric vehicle according to one embodiment of the present invention.

[0034] 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. While this specification focuses on an EV (10), it is apparent that the description can also be applied to a plug-in hybrid electric road vehicle (PHEV).

[0035] 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.

[0036] 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.

[0037] Here, the charging device (100) can communicate with the EV (10) and EVSE (20), respectively.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] In mode 2, mode 3 and mode 4, the CP function is performed through a CP circuit using PWM (pulse wide modulation).

[0042] Figures 3 and 4 illustrate electrical equivalent circuits of a CP circuit.

[0043] Referring to FIGS. 3 and 4, if the EV (10) draws a current higher than the CP function (duty cycle), the EVSE (20) may open its switching device. At this time, the EVSE (20) will follow the conditions of the allowed response time of the EV (10), the current tolerance with respect to the duty cycle generated by the EVSE (20), and the tolerance of the current measurement in the EVSE (20) itself.

[0044] Referring to FIG. 3, 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.

[0045] Referring to Fig. 4, the EV (10) using the simplified CP circuit will be limited to single-phase charging and will not exceed a current of 10 A. The EVSE (20) can support the EV (10) using the simplified CP circuit. In this case, the EVSE (20) will modulate the PWM signal in the same manner as the EV (10) using the general CP circuit of Fig. 3. The EV (10) using the simplified CP circuit can measure the duty cycle.

[0046] Figure 5 shows a CP signal in PWM form output by EVSE.

[0047] Referring to Fig. 5, EVSE (20) outputs a CP signal in PWM form with a maximum voltage of +12 V and a minimum voltage of -12 V. EVCC (100), which is a charging device of EV (10), detects the CP signal to monitor and control the status.

[0048] 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 when the peak of the CP signal is +12 V ± 1 V, it is determined to be state A. 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 state in which charging is ready. 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 state in which charging is in progress, that is, a charging state, and in particular, state D may mean a state in which ventilation is required 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.

[0049] Interaction between the EVSE (20) and the EV (10) can be monitored and controlled through the CP signal, and as described above, the voltage level of the CP signal can vary depending on the charging state. Accordingly, the charging device (100) of the EV (10) must detect the voltage level of the CP signal.

[0050] In general, the charging device (100) can detect the positive voltage, which is the maximum voltage, and the negative voltage, which is the minimum voltage, of the CP signal, and determine the status between the EVSE (20) and the EV (10) based on the detected maximum and minimum voltages. According to an embodiment of the present invention, the charging device (100) aims to efficiently monitor the charging status between the EVSE (20) and the EV (10) based on the CP signal.

[0051] 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.

[0052] 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 first voltage detection unit (120), a second voltage 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.

[0053] 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).

[0054] 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).

[0055] 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).

[0056] The first voltage detection unit (120) detects the first voltage of the CP signal (S710), the second voltage detection unit (130) detects the second voltage of the CP signal (S720), and the control unit (140) calculates the third voltage, which is the difference between the first voltage and the second voltage (S730).

[0057] Here, the first voltage is the maximum voltage of the CP signal in PWM form, the second voltage is the difference between the maximum voltage and the minimum voltage of the CP signal in PWM form, i.e., the amplitude, and the third voltage may be the minimum voltage of the CP signal in PWM form. Here, the maximum voltage may be mixed with a positive voltage peak, the minimum voltage may be mixed with a negative voltage peak, and the amplitude may be mixed with peak-to-peak.

[0058] That is, the first voltage detection unit (120) detects the maximum voltage of the CP signal, the second voltage detection unit (130) detects the difference between the maximum voltage and the minimum voltage of the CP signal, that is, the amplitude, and the control unit (140) calculates the minimum voltage of the CP signal, that is, the negative voltage peak of the CP signal, by using the maximum voltage of the CP signal detected by the first voltage detection unit (120) and the difference between the maximum voltage and the minimum voltage of the CP signal detected by the second voltage detection unit (130). For example, when the control unit (140) subtracts the difference between the maximum voltage and the minimum voltage of the CP signal detected by the second voltage detection unit (130) from the maximum voltage of the CP signal detected by the first voltage detection unit (120), the minimum voltage of the CP signal, that is, the negative voltage peak of the CP signal, can be calculated. For example, if the positive voltage peak of the CP signal is +9 V and the negative voltage peak is -12 V, the first voltage detection unit (120) detects +9 V, the second voltage detection unit (120) detects +21 V (=+9 V-(-12 V)), which is the difference between the positive voltage peak (+9 V) and the negative voltage peak (-12 V), and the control unit (140) can calculate -12 V (=+9 V-(+21 V)), which is the negative voltage peak, by using the difference between +9 V detected by the first voltage detection unit (120) and +21 V detected by the second voltage detection unit (130).

[0059] Accordingly, circuit implementation is easy because there is no need to directly detect the negative voltage peak.

[0060] According to an embodiment of the present invention, the control unit (140) determines the charging state of the charging device (100) using the first voltage detected by the first voltage detection unit (120) and the third voltage calculated by the control unit (140) (S740). Here, the charging state of the charging device (100) may be one of a charger not connected state, a charger connected state, a charging state, and an error state. The charger connected state may mean a state in which the charger is connected but not charging. The charging state may be determined according to Table 1.

[0061] State 1st voltage 2nd voltage 3rd voltage Description A state +11V~+13V+23V~+25V-13V~-11V Charger not connected B state +8V~+10V+20V~+22V-13V~-11V Charger connected C state +5V~+7V+17V~+19V-13V~-11V Charging D state +2V~+4V+14V~+16V-13V~-11V Charging (ventilation required) E state -1V~+1V+11V~+13V-13V~-11V Error F state -13V~-11V-1V~+1V-13V~-11V Error

[0062] That is, if the first voltage detected by the first voltage detection unit (120) is +11 V to +13 V and the second voltage detected by the second voltage detection unit (130) is +23 V to +25 V, the third voltage may be calculated by the control unit (140) to be -13 V to -11 V and may be determined as the A state, which is a charger-disconnected state. In addition, if the first voltage detected by the first voltage detection unit (120) is +8 V to +10 V and the second voltage detected by the second voltage detection unit (130) is +20 V to +22 V, the third voltage may be calculated by the control unit (140) to be -13 V to -11 V and may be determined as the B state, which is a charger-connected state. In addition, if the first voltage detected by the first voltage detection unit (120) is +5 V to +7 V and the second voltage detected by the second voltage detection unit (130) is +17 V to +19 V, the third voltage may be calculated as -13 V to -11 V by the control unit (140) and determined as the C state, which is a charging state. In addition, if the first voltage detected by the first voltage detection unit (120) is +2 V to +4 V and the second voltage detected by the second voltage detection unit (130) is +14 V to +16 V, the third voltage may be calculated as -13 V to -11 V by the control unit (140) and determined as the D state, which is a charging state (ventilation required). In addition, if the first voltage detected by the first voltage detection unit (120) is -1 V to +1 V and the second voltage detected by the second voltage detection unit (130) is +11 V to +13 V, the third voltage may be calculated as -13 V to -11 V by the control unit (140) and determined as an E state, which is an error state. In addition, if the first voltage detected by the first voltage detection unit (120) is -13 V to -11 V and the second voltage detected by the second voltage detection unit (130) is -1 V to +1 V, the third voltage may be calculated as -13 V to -11 V by the control unit (140) and determined as an F state, which is an error state.

[0063] In this way, according to an embodiment of the present invention, the charging state of the charging device (100) can be accurately and efficiently detected without directly detecting the negative voltage peak of the CP signal.

[0064] Figure 8 is a CP signal detection circuit according to one embodiment of the present invention.

[0065] Referring to Fig. 8, the EVSE (20) side circuit and the EV (10) side circuit are arranged with a connection node (Nc) between them. The EVSE (20) side circuit outputs a CP signal in the form of PWM, and the CP signal in the form of PWM is input to the EV (10) side circuit through the connection node (Nc). The EVSE (20) side circuit is illustrated as including a resistor (R31) and a filter unit (21), and the resistor (R31) can be designed to be 1 kΩ, but is not limited thereto.

[0066] The EV (10) side circuit may include a filter unit (11) and an EVCC standard resistor (12) arranged between the connection node (Nc) and the first node (N1). Here, the filter unit (11) may include at least one of an ESD (electrostatic discharge) filter, a surge filter, an EMC (electromagnetic compatibility) filter, and an EMI (electromagnetic interference) filter. The voltage of the CP signal for each charging state may be sequentially changed by the voltage division of the resistor (R31) of the EVSE (20) side circuit and the EVCC standard resistor (12).

[0067] In the EV (10) side circuit, the connection node (Nc) may be included in the connection portion (110) of Fig. 6. The connection portion (110), the first voltage detection portion (120), and the second voltage detection portion (130) are connected to the first node (N1).

[0068] According to an embodiment of the present invention, the second voltage detection unit (130) may include a first capacitor (C1), a second capacitor (C2), a first diode (D1), and a second diode (D2). One end of the first capacitor (C1) may be connected to a first node (N1) between the connection unit (110) and the first voltage detection unit (120), and the other end of the first capacitor (C1) may be connected to the first diode (D1) and the second diode (D2). One end of the first diode (D1) may be connected to the first capacitor (C1), and the other end of the first diode (D1) may be connected to ground. One end of the second diode (D2) may be connected to the other end of the first capacitor (C1) and one end of the first diode (D1), and the other end of the second diode (D2) may be connected to the second capacitor (C2). One end of the second capacitor (C2) may be connected to the other end of the second diode (D2), and the other end of the second capacitor (C2) may be connected to ground. The second voltage detection unit (130) may further include a resistor (R1) connected between the other end of the second diode (D2) and one end of the second capacitor (C2). Here, the resistor (R1) may be designed to be 1 kΩ, but is not limited thereto. When a CP signal in the form of PWM is input to the second voltage detection unit (130), the positive voltage component and the negative voltage component of the CP signal are synthesized to detect the overall voltage, i.e., the amplitude of the PWM. For example, when a negative voltage component and a positive voltage component are alternately input through a CP signal in the form of PWM, the negative voltage component is charged into a positive voltage component through the first capacitor (C1) and the first diode (D1) of the second voltage detection unit (130), and is then synthesized with the input positive voltage component through the first capacitor (C1), the first diode (D1), and the second diode (D2), and the entire voltage can be detected due to the smoothing effect of the second capacitor (C2).For example, when -12 V and +12 V are alternately input to the second voltage detection unit (130), -12 V is charged to +12 V by the first capacitor (C1) and the first diode (D1), and then synthesized with the input +12 V, and a voltage of +24 V can be continuously detected due to the smoothing effect of the second capacitor (C2). For this purpose, the first diode (D1) and the second diode (D2) can be arranged in opposite directions. For example, among the terminals of the first diode (D1), one terminal connected between the first capacitor (C1) and the second diode (D2) may be a cathode, and the other terminal connected to the ground may be an anode. Among the terminals of the second diode (D2), one terminal connected to the first capacitor (C1) and the first diode (D1) may be an anode, and the other terminal connected to the second capacitor (C2) may be a cathode. In addition, the capacitance of the first capacitor (C1) may be larger than the capacitance of the second capacitor (C2). Here, the first diode (D1) and the second diode (D2) may be Schottky barrier diodes. Accordingly, a fast switching characteristic can be obtained.

[0069] According to an embodiment of the present invention, the first voltage detection unit (120) may include a third capacitor (C3) and a third diode (D3). One end of the third diode (D3) may be connected to the first node (N1), and the other end of the third diode (D3) may be connected to one end of the third capacitor (C3). The other end of the third capacitor (C3) may be connected to ground. When a CP signal in the form of PWM is input to the first voltage detection unit (120), the third diode (D3) and the third capacitor (C3) may function as a smoothing circuit to detect a positive voltage component of the CP signal. For example, when the highest voltage of the CP signal in the form of PWM is +12 V, a continuous voltage of +12 V may be detected due to the smoothing effect of the third capacitor (C3). Here, the third diode (D3) may be a Schottky barrier diode. According to this, fast switching characteristics can be obtained.

[0070] At this time, the second node (N2) between the second diode (D2) and the second capacitor (C2) of the second voltage detection unit (130) and the third node (N3) between the third diode (D3) and the third capacitor (C3) of the first voltage detection unit (120) may be connected to an MCU included in the control unit (140), respectively. Accordingly, the first voltage detected by the first voltage detection unit (120) and the second voltage detected by the second voltage detection unit (130) are each input to the control unit (140), the third voltage is calculated by the control unit (140), and the charging state of the charging device (100) may be detected.

[0071] In this way, according to an embodiment of the present invention, the charging device (100) can calculate the negative voltage component of the CP signal without implementing a circuit for directly detecting the negative voltage component of the CP signal. Accordingly, the circuit complexity is significantly reduced. In particular, according to an embodiment of the present invention, since neither the first voltage detection unit (120) nor the second voltage extraction unit (130) includes active elements, low-cost implementation is possible, the circuit complexity is reduced, so the defect rate can be reduced, and the area of ​​the PCB for implementing the circuit can be reduced, so space utilization can also be improved.

[0072] Figures 9 to 13 are simulation results when various CP signals are input to a circuit according to an embodiment of the present invention.

[0073] Referring to FIG. 9, when a PWM signal having a maximum voltage of +12 V and a minimum voltage of -12 V is input, it can be seen that a voltage of about 24 V is detected by the second voltage detection unit (130), a voltage of about 12 V is detected by the first voltage detection unit (120), and a negative voltage component of about -12 V is calculated by the MCU.

[0074] Referring to FIG. 10, when a PWM signal having a maximum voltage of +9 V and a minimum voltage of -12 V is input, it can be seen that a voltage of about 21 V is detected by the second voltage detection unit (130), a voltage of about 9 V is detected by the first voltage detection unit (120), and a negative voltage component of about -12 V is calculated by the MCU.

[0075] Referring to FIG. 11, when a PWM signal having a maximum voltage of +6 V and a minimum voltage of -12 V is input, it can be seen that a voltage of about 18 V is detected by the second voltage detection unit (130), a voltage of about 6 V is detected by the first voltage detection unit (120), and a negative voltage component of about -12 V is calculated by the MCU.

[0076] Referring to FIG. 12, when a PWM signal having a maximum voltage of +3 V and a minimum voltage of -12 V is input, it can be seen that a voltage of about 15 V is detected by the second voltage detection unit (130), a voltage of about 3 V is detected by the first voltage detection unit (120), and a negative voltage component of about -12 V is calculated by the MCU.

[0077] Referring to FIG. 13, when a PWM signal having a maximum voltage of +0 V and a minimum voltage of -12 V is input, it can be seen that a voltage of about 12 V is detected by the second voltage detection unit (130), a voltage of about 0 V is detected by the first voltage detection unit (120), and a negative voltage component of about -12 V is calculated by the MCU.

[0078] In this way, according to an embodiment of the present invention, it can be seen that the negative voltage of a CP signal can be calculated using a low-cost, low-complexity circuit, and thus, the charging state of the charging device (100) can be easily detected.

[0079] 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.

[0080] [Explanation of symbols]

[0081] 10: Electric cars

[0082] 20: Electric vehicle charging facilities

[0083] 22: Charging cable

[0084] 100: Charging device

[0085] 110: Connector

[0086] 120: First voltage detection unit

[0087] 130: Second voltage detection unit

[0088] 140: Control Unit

Claims

1. In a charging device for an electric vehicle, A connection that receives a CP (Control Pilot) signal in the form of PWM (Pulse Wide Modulation). A first voltage detection unit that detects the first voltage of the CP signal; A second voltage detection unit that detects the second voltage of the CP signal; A control unit is included that calculates a third voltage which is a difference between the first voltage and the second voltage, and determines the charging state of the charging device using the detected first voltage and the calculated third voltage. A charging device wherein the first voltage is the maximum voltage of the CP signal, the second voltage is the difference between the maximum voltage and the minimum voltage of the CP signal, and the third voltage is the minimum voltage of the CP signal.

2. In paragraph 1, The charging status of the above charging device is one of the following: charger not connected, charger connected, charging, and error.

3. In paragraph 1, If the first voltage detected by the first voltage detection unit is +11 V to +13 V and the second voltage detected by the second voltage detection unit is +23 V to +25 V, the charger is determined to be unconnected. If the first voltage detected by the first voltage detection unit is +8 V to +10 V and the second voltage detected by the second voltage detection unit is +20 V to +22 V, it is determined that the charger is connected. If the first voltage detected by the first voltage detection unit is +5 V to +7 V and the second voltage detected by the second voltage detection unit is +17 V to +19 V, or the first voltage detected by the first voltage detection unit is +2 V to +4 V and the second voltage detected by the second voltage detection unit is +14 V to +16 V, it is determined that the charging state is in progress. A charging device that is determined to be in an error state when the first voltage detected by the first voltage detection unit is -1 V to +1 V and the second voltage detected by the second voltage detection unit is +11 V to +13 V, or when the first voltage detected by the first voltage detection unit is -13 V to -11 V and the second voltage detected by the second voltage detection unit is -1 V to +1 V.

4. In paragraph 1, A charging device comprising: a first capacitor having one end connected to a first node between the connecting portion and the first voltage detecting portion; a first diode having one end connected to the other end of the first capacitor and the other end connected to ground; a second diode having one end connected to one end of the first diode; and a second capacitor having one end connected to the other end of the second diode and the other end connected to ground.

5. In paragraph 4, A charging device wherein the second voltage detection unit further includes a resistor connected between the other end of the second diode and one end of the second capacitor.

6. In paragraph 4, A charging device in which the first voltage detection unit includes a third diode having one end connected to the first node and a third capacitor having one end connected to the other end of the third diode and the other end connected to ground.

7. In paragraph 6, A charging device in which the second node between the second diode and the second capacitor of the second voltage detection unit and the third node between the third diode and the third capacitor of the first voltage detection unit are each connected to the control unit.

8. In paragraph 1, A charging device further comprising a filter unit disposed between the connecting unit and the first node.

9. In a method for controlling a charging device for an electric vehicle, A step for receiving a CP (Control Pilot) signal in the form of PWM (Pulse Wide Modulation), A step of detecting the first voltage of the CP signal, A step of detecting the second voltage of the CP signal, a step of calculating a third voltage which is the difference between the first voltage and the second voltage, and A step of determining the charging state of the charging device using the detected first voltage and the calculated third voltage, A control method wherein the first voltage is the maximum voltage of the CP signal, the second voltage is the difference between the maximum voltage and the minimum voltage of the CP signal, and the third voltage is the minimum voltage of the CP signal.

10. In paragraph 9, A control method in which the charging status of the above charging device is one of a charger unconnected state, a charger connected state, a charging state, and an error state.

Images