Patent Description:
In recent times, as environmental awareness rises, developing electric vehicles powered by electricity to replace traditional automobiles powered by fossil-based fuels has gradually becoming an important target of automobile industry.

However, in order to reduce charging time, an electric vehicle supply equipment nowadays requires high power to charge the electric vehicles. As a result, a charging socket is easily damaged and burnout due to high temperature, thus raising safety concerns.

Therefore, how to design a charge gun and an EVSE with an over-temperature protecting function is an important research topic in the field.

<CIT> & <CIT> discloses a temperature sensor connected between a ground conductor and a high voltage conductor L1 in the charging handle, wherein the charging handle includes a return conductor L2/N and the temperature sensor includes a thermistor R1-NTC.

<CIT> discloses a charging system for an electric or hybrid vehicle comprising an alternating current charging connector capable of being connected to a domestic electricity distribution network via an electrical connection socket provided with a temperature-sensitive device, and processing means for determining the use or not of a domestic charging mode.

<CIT> discloses a secure electrical socket comprising power contacts capable of cooperating with complementary power contacts of a complementary electrical socket, the electrical socket comprising a first temperature sensor mounted near the power contacts of the electrical outlet, the electrical outlet comprising a second temperature sensor remote from the power contacts of the electrical outlet.

<CIT> discloses an electric vehicle supply equipment (EVSE) for charging the on-board battery pack of an electric vehicle.

<CIT> discloses an electric vehicle support equipment (EVSE) system that includes a nozzle configured to couple to an electric vehicle, the nozzle including a first microcontroller (MCU), wherein the EVSE also includes a charging circuit interrupt device (CCID) configured to couple to a power source, the CCID including a second MCU and a cable that is coupled between the CCID and the nozzle.

<CIT> discloses a circuit for temperature measurement in a charging handle of an electric vehicle charging station, comprising: a temperature sensor connected between a control pilot line and a ground line in a charging handle of an electric vehicle charging station.

Preferred embodiments are included as dependent claims.

It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the disclosure as claimed.

The disclosure can be more fully understood by reading the following detailed description of the embodiments, with reference made to the accompanying drawings as follows:.

Reference will now be made in detail to embodiments of the present disclosure, examples of which are described herein and illustrated in the accompanying drawings. While the disclosure will be described in conjunction with embodiments, it will be understood that they are not intended to limit the disclosure to these embodiments. On the contrary, the disclosure is intended to cover alternatives, modifications and equivalents, which may be included within the scope of the disclosure as defined by the appended claims. It is noted that, in accordance with the standard practice in the industry, the drawings are only used for understanding and are not drawn to scale. Hence, the drawings are not meant to limit the actual embodiments of the present disclosure. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts for better understanding.

The terms used in this specification and claims, unless otherwise stated, generally have their ordinary meanings in the art, within the context of the disclosure, and in the specific context where each term is used. Certain terms that are used to describe the disclosure are discussed below, or elsewhere in the specification, to provide additional guidance to the practitioner skilled in the art regarding the description of the disclosure.

The terms "about" and "approximately" in the disclosure are used as equivalents. Any numerals used in this disclosure with or without "about," "approximately," etc. are meant to cover any normal fluctuations appreciated by one of ordinary skill in the relevant art. In certain embodiments, the term "approximately" or "about" refers to a range of values that fall within <NUM>%, <NUM>%, <NUM>%, or less in either direction (greater or less than) of the stated reference value unless otherwise stated or otherwise evident from the context.

In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to.

In this document, the term "coupled" may also be termed "electrically coupled," and the term "connected" may be termed "electrically connected. " "Coupled" and "connected" may also be used to indicate that two or more elements cooperate or interact with each other. It will be understood that, although the terms "first," "second," etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the embodiments.

Reference is made to <FIG> is a diagram illustrating charging of an electric vehicle according to some embodiments of the present disclosure. As shown in <FIG>, a charging device 100a is configured to charge an electric vehicle (EV) <NUM>. In some embodiments, the charging device 100a may be an Electric Vehicle Supply Equipment (EVSE), which includes a charging module <NUM>, a charging wire <NUM> and a charge gun <NUM>. The charge gun <NUM> is connected to the charging module <NUM> through the charging wire <NUM>, and is configured to transmit electricity power through the charging wire <NUM>. Thus, the charge gun <NUM> may be configured to charge the electric vehicle <NUM> when being connected to the electric vehicle <NUM>.

Specifically, in some embodiments, the charge gun <NUM> includes multiple terminals corresponding to a socket <NUM> of the electric vehicle <NUM>, such that the charge gun <NUM> and the electric vehicle <NUM> may be electrically coupled to each other. For example, in the embodiment shown in <FIG>, the charge gun <NUM> includes charging terminals P1-P3 and PN, a ground terminal PE, a control pilot terminal CP and a connection confirming terminal CC.

When the charge gun <NUM> is connected to the electric vehicle <NUM>, the charging terminals P1-P3 in the charge gun <NUM> are configured to be electrically coupled to a power storage system <NUM> in the electric vehicle <NUM> through the corresponding terminals on the socket <NUM> in the electric vehicle <NUM>, thereby charging the electric vehicle <NUM>. For example, the power storage system <NUM> may be an EV onboard charger system. As shown in <FIG>, in some embodiments, the charging device 100a may be an AC type charging device, and the charging terminals P1-P3 are configured to provide three-phase AC power, and the charging terminal PN may be a neutral point of the three-phase electricity system, but the present disclosure is not limited thereto. For example, in some other embodiments, the charging device 100a may also be a DC type charging device, and is configured to provide DC power to the electric vehicle <NUM> through corresponding charging terminals.

The ground terminal PE in the charge gun <NUM> is electrically coupled to an equipment ground GND1 in the charging device 100a through the charging wire <NUM>, and corresponds to the terminal electrically coupled to an EV ground GND2 on the socket <NUM> in the electric vehicle <NUM>. Thus, when the charge gun <NUM> is connected to the electric vehicle <NUM>, both sides of the charging device 100a and the electric vehicle <NUM> may have the same reference levels.

The connection confirming terminal CC in the charge gun <NUM> is configured to be electrically coupled to the electric vehicle <NUM>, and is configured to enable the control circuit in the electric vehicle <NUM> to detect whether a user is connecting the charge gun <NUM> to the socket <NUM> of the electric vehicle <NUM>, or is plugging out the charge gun <NUM> from the socket <NUM> of the electric vehicle <NUM>, so as to switch off the electricity path immediately to prevent accidents from happening.

The control pilot terminal CP in the charge gun <NUM> is configured to transmit a control pilot signal Vcp1 between the charge gun <NUM> and the electric vehicle <NUM>, such that the control circuit in the charging device 100a and the electric vehicle <NUM> may detect charging information such as whether the charge gun <NUM> is connected to or detached from the electric vehicle <NUM>, whether the charging preparation is completed, the amount of the charging current required by the electric vehicle <NUM>, and whether the charging process is completed, according to a voltage level and a duty cycle of the control pilot signal Vcp1, in which specific operations will be explained in details in the following paragraphs.

As shown in <FIG>, the charging module <NUM> in the charging device 100a includes a control circuit <NUM> electrically coupled to the control pilot terminal CP through the charging wire <NUM>, and is configured to control the charge gun <NUM> to charge the electric vehicle <NUM> through the charging terminals P1-P3 and PN according to the control pilot signal Vcp1.

Specifically, in some embodiments, when the charge gun <NUM> is not connected to the electric vehicle <NUM>, the switching unit S1 in the charging module <NUM> is configured to be switched to the node a, such that the first terminal of the resistance unit R1 receives a predetermined voltage V1 of a first level (e.g., about <NUM> Volts). Meanwhile, the control pilot signal Vcp1 received by the control circuit <NUM> from the second terminal of the resistance unit R1 is also at the first level.

When the charge gun <NUM> and the electric vehicle <NUM> are connected, since the charging device 100a and the electric vehicle <NUM> are commonly grounded via the ground terminal PE, the resistance unit R1 in the charging module <NUM> and the diode unit D1 and the resistance unit R3 in the electric vehicle <NUM> are electrically coupled in series, and form an electricity path such that the voltage level of the control pilot signal Vcp1 is voltage divided to a second level (e.g., about <NUM> volts) that is lower than the first level.

Meanwhile, the control circuit <NUM> detects changes of the control pilot signal Vcp1, and controls the switching unit S1 to be switched to the node b, such that the first terminal of the resistance unit R1 receives a pulse width modulation signal PWM (e.g., a switching signal having a high level of about <NUM> Volts and a low level of about -<NUM> Volts). Thus, since the diode unit D1 is turned on in the forward period, such that the resistance unit R1 and the resistance unit R3 are electrically coupled in series for dividing voltage, and the diode unit D1 is turned off in the reversed period, the control pilot signal Vcp1 is configured to be switching between the second level (e.g., about <NUM> volts) and the low level (e.g., about -<NUM> volts).

Thus, the control circuit <NUM> in the electric vehicle <NUM> may be configured to check a state of the charging device 100a by detecting the control pilot signal Vcp1, and to perform charging preparation. For example, the control circuit <NUM> may output a corresponding signal to turn on the switching unit S2, such that the resistance unit R2 and the resistance unit R3 are electrically coupled in parallel. Accordingly, the control pilot signal Vcp1 will switch between a third level (e.g., about <NUM> volts) that is lower than the second level and the low level (e.g., about -<NUM> volts) due to the electricity path formed by the resistance unit R2. Meanwhile, the control circuit <NUM> may control the power line L1-L3 and LN of the charging device 100a to start supplying power correspondingly after detecting the change of the control pilot signal Vcp1, and to charge the power storage system <NUM> in the electric vehicle <NUM> through the charging terminal P1-P3 and PN of the charge gun <NUM>.

When the charging of the electric vehicle <NUM> is completed or desired to be terminated, the control circuit <NUM> may be used to correspondingly control the on and off of the switching unit S2, and the control circuit <NUM> may be used to correspondingly control the switching of the switching unit S1, thereby enabling the control pilot signal Vcp1 to have specific levels to notify the charging device 100a to stop supplying power, in which such specific operations may be achieved by executing the aforementioned operations reversely, and thus further explanation is omitted for the sake of brevity.

Reference is again made to <FIG>. In some embodiments, the charge gun <NUM> further includes an over temperature detecting circuit 142a and a connection confirming circuit <NUM>, in addition to the multiple terminals. Specifically, the over temperature detecting circuit 142a is electrically coupled between the ground terminal PE (i.e., the equipment ground GND1) and the control pilot terminal CP.

The connection confirming circuit <NUM> is electrically coupled between the connection confirming terminal CC and the ground terminal PE, and is configured to output a connection confirming signal Vcc to the control circuit <NUM> in the electric vehicle <NUM>, so as to control the charging of the electric vehicle <NUM> performed by the charge gun <NUM>.

Specifically, in some embodiments, the connection confirming circuit <NUM> includes resistance units R4 and RC, and a switching unit S3. The resistance unit R4 and the switching unit S3 are electrically coupled in parallel, and then are electrically coupled to the resistance unit RC in series. The switching unit S3 may be a normally closed switch which is conductive and bypasses the resistance unit R4 terminal at normal time. When the user is about to plug out the charge gun <NUM> and presses an operating button on the charge gun <NUM>, the switching unit S3 is turned off correspondingly and the overall resistance value of the connection confirming circuit <NUM> is changed, and then the voltage level of the connection confirming signal Vcc is further changed. Therefore, the control circuit <NUM> may perform corresponding control to stop the power transmission between the charging device 100a and the electric vehicle <NUM> when detecting the change of the voltage level of the connection confirming signal Vcc, thereby ensuring the safety of the user and the charging system.

The over temperature detecting circuit 142a includes a temperature sensor ST1, and the temperature sensor ST1 changes correspondingly when the temperature sensor ST1 detects that a temperature of the charge gun <NUM> exceeds a safety limit value. Specifically, the temperature sensor ST1 is realized by various circuit elements such as temperature switches. According to the present invention, the temperature sensor ST1 includes a temperature switch. The temperature switch is turned off when the temperature of the charge gun <NUM> is lower than the safety limit value. On the other hand, the temperature switch is turned on when the temperature of the charge gun <NUM> exceeds the safety limit value. In another example not being part of the present invention, the over temperature detecting circuit 142a may change the overall resistance value of the over temperature detecting circuit 142a by changing the resistance of the temperature sensor ST1 to different states, and then may change the waveform characteristics of the control pilot signal Vcp1.

For example, as shown in <FIG>, in some embodiments, the over temperature detecting circuit 142a includes a resistance unit RT1 electrically coupled to the temperature sensor ST1 in series.

Reference is made to <FIG> together with <FIG>. <FIG> is a waveform diagram illustrating the control pilot signal Vcp1 shown in <FIG> according to some embodiments of the present disclosure. As shown in <FIG>, in a period T1, the temperature switch is turned off when the temperature of the charge gun <NUM> is lower than the safety limit value, and thus the control pilot signal Vcp1 switches between the high level VH1 and the low level VL1. For example, the high level VH1 may be about <NUM> volts and the low level VL1 may be about -<NUM> volts.

When the temperature of the charge gun <NUM> exceeds the safety limit value and the temperature switch is turned on to cause the resistance of the over temperature detecting circuit 142a to be changed, since the temperature sensor ST1 and the resistance unit R1 are electrically coupled in series between the control pilot terminal CP and the equipment ground GND1, the control pilot signal Vcp1 switches between the high level VH2 and the low level VL2 after being voltage divided at this time, as shown in the period T2 in <FIG>.

In some embodiments, the high level VH2 is lower than the high level VH1, and the low level VL2 is higher than the low level VL1. For example, in some embodiments, the high level VH2 may be about <NUM> volts, and the low level VL2 may be about -<NUM> volts, but the present disclosure is not limited thereto. One skilled in the art may arrange the resistance value of the resistance unit R1-R3 and the resistance unit RT1 based on actual needs, so as to adjust the voltage waveform of the control pilot signal Vcp1. In addition, as stated in the above paragraphs, the temperature sensor ST1 may be implemented by various circuit elements such as thermistors, such that the over temperature detecting circuit 142a has different resistance values under a normal operation and an over temperature operation, and then the waveform characteristics of the control pilot signal Vcp1 can be further realized, as illustrated in <FIG>.

Therefore, the control circuit <NUM> in the charging module <NUM> determines whether the temperature of the charge gun <NUM> exceeds the safety limit value by detecting the control pilot signal Vcp1, and performs protection operations accordingly. For example, in some embodiments, the control circuit <NUM> controls the charging module <NUM> to lower the output to the electric vehicle <NUM> when the control circuit <NUM> determines that over temperature occurs in the charge gun <NUM>. In some other embodiments, the control circuit <NUM> may also control the charging module <NUM> to stop charging the electric vehicle <NUM>, or to output a warning signal. For example, the control circuit <NUM> may collaborate with an audio module, a lighting module, or a display module etc. to warn the user with sound or light that charging is abnormal.

Accordingly, there is no need to design extra signal lines for transmitting the temperature detection signal in the charging wire <NUM>, and the abnormal temperature information may be provided to the control circuit <NUM> in the charging device 100a by the control pilot signal Vcp1. Therefore, the charging wire <NUM> may be simplified and the design cost of the charging wire <NUM> may be reduced. In some embodiments, the control circuit <NUM> of the electric vehicle <NUM> may also receive the abnormal temperature information by the control pilot signal Vcp1 and stop the charging operations from the electric vehicle <NUM> side to protect the electric vehicle <NUM>.

Reference is made to <FIG> is a diagram illustrating a charging device 100b according to some examples not being part of the present invention. With respect to <FIG>, in which like elements in <FIG> are designated with the same reference numbers for ease of understanding. As shown in <FIG>, in another example not being part of the present invention, the over temperature detecting circuit 142b may include the temperature sensor ST1 and a diode unit DT1. In the embodiment shown in <FIG>, the diode unit DT1 is electrically coupled to the temperature sensor ST1 in series. Specifically, the anode terminal of the diode unit DT1 is electrically coupled to the temperature sensor ST1, and the cathode terminal of the diode unit DT1 is electrically coupled to the control pilot terminal CP.

Reference is made to <FIG> together with <FIG>. <FIG> is a waveform diagram illustrating a control pilot signal Vcp2 shown in <FIG>. As shown in <FIG>, in a period T1, the temperature sensor ST1 is turned off when the temperature of the charge gun <NUM> is lower than the safety limit value, and thus the control pilot signal Vcp2 switches between the high level VH1 and the low level VL1. For example, the high level VH1 may be about <NUM> volts and the low level VL1 may be about -<NUM> volts.

When the temperature of the charge gun <NUM> exceeds the safety limit value, the temperature sensor ST1 is turned on to enable the diode unit DT1 to be coupled between the control pilot terminal CP and the equipment ground GND1. Thus, in the forward period, the diode unit DT1 is off and the level of the control pilot signal Vcp2 remains unchanged. On the other hand, in the reversed period, the diode unit DT1 is on and the low level of the control pilot signal Vcp2 is clamped at the low level VL2, as shown in the period T2 in <FIG>. For example, in some embodiments, the high level VH1 may be about <NUM> volts, the low level VL1 may be about -<NUM> volts, and the low level VL2 may be about -<NUM> volts, but the present disclosure is not limited thereto. One skilled in the art may arrange the diode unit DT1 based on actual needs to adjust the voltage waveform of the control pilot signal Vcp2. In addition, in some embodiments, the over temperature detecting circuit 142b may further include a resistance unit electrically coupled to the diode unit DT1 in series to further adjust the voltage level of the control pilot signal Vcp2, in which the operations are discussed in the aforementioned embodiments, and thus are omitted herein for the sake of brevity.

Reference is made to <FIG> is a diagram illustrating a charging device 100c according to some other embodiments of the present disclosure. With respect to <FIG> and <FIG>, like elements in <FIG> are designated with the same reference numbers for ease of understanding. Compared to the embodiment shown in <FIG>, in the embodiment shown in <FIG>, the over temperature detecting circuit 142b also includes the temperature sensor ST1 and the diode unit DT1, but the cathode terminal of the diode unit DT1 is electrically coupled to the temperature sensor ST1, and the anode terminal of the diode unit DT1 is electrically coupled to the control pilot terminal CP.

Reference is made to <FIG> together with <FIG>. <FIG> is a waveform diagram illustrating a control pilot signal Vcp3 shown in <FIG> according to some embodiments of the present disclosure. As shown in <FIG>, similar to the aforementioned embodiments, in a period T1, the temperature sensor ST1 is turned off when the temperature of the charge gun <NUM> is lower than the safety limit value, and thus the control pilot signal Vcp3 switches between the high level VH1 and the low level VL1. For example, the high level VH1 may be about <NUM> volts and the low level VL1 may be about -<NUM> volts.

When the temperature of the charge gun <NUM> exceeds the safety limit value, the temperature sensor ST1 is turned on such that the diode unit DT1 is coupled between the control pilot terminal CP and the equipment ground GND1. Thus, in the reversed period, the diode unit DT1 is off and the level of the control pilot signal Vcp3 remains unchanged. On the other hand, in the forward period, the diode unit DT1 is on and the high level of the control pilot signal Vcp3 is clamped at the high level VH2, as shown in the period T2 in <FIG>. For example, in some embodiments, the low level VL1 may be about -<NUM> volts, the high level VH1 may be about <NUM> volts, and the high level VH2 may be about <NUM> volts, but the present disclosure is not limited thereto. One skilled in the art may arrange the diode unit DT1 based on actual needs to adjust the voltage waveform of the control pilot signal Vcp3. In addition, in some embodiments, the over temperature detecting circuit 142c may further include a resistance unit electrically coupled to the diode unit DT1 in series to further adjust the voltage level of the control pilot signal Vcp3, in which the operations are clearly discussed in the aforementioned embodiments, and thus are omitted herein for the sake of brevity.

Alternatively stated, as discussed in the various embodiments mentioned above, the over temperature detecting circuits 142a-142c may be implemented in various ways. When the temperature of the charge gun <NUM> exceeds the safety limit value, the over temperature detecting circuits 142a-142c control a positive level and/or a negative level of the control pilot signals Vcp1-Vcp3 to be switched from a first level to a second level that is different from the first level. Therefore, the control circuit <NUM> may perform over temperature protection according to the level changes of the control pilot signal Vcp1-Vcp3. Specifically, when the positive level or the negative level of the control pilot signal Vcp1-Vcp3 is at the second level, the control circuit <NUM> is configured to control the charge gun <NUM> to stop charging the electric vehicle <NUM> according to the control pilot signal Vcp1-Vcp3. In addition, in some embodiments, the control circuit <NUM> may also control the charging device 100a-100c to lower the output or to output the warning signal.

It is noted that, in some embodiments, the temperature sensor ST1 in the charge gun <NUM> may be arranged adjacent to each terminal of the charge gun <NUM> to sense the temperature of the charge gun <NUM>. In some embodiments, plural temperature sensors may be arranged in the over temperature detecting circuit to increase the sensitivity of the temperature sensing.

Reference is made to <FIG> is a diagram illustrating a charging device 100d according to some examples not being part of the present invention. As shown in the figure, in another example not being part of the present invention, the over temperature detecting circuit 142d includes the temperature sensors ST1 and ST2 electrically coupled in parallel, the diode unit DT1 and the resistance unit RT1. Therefore, when any one of the temperature sensors ST1 and ST2 detects that temperature exceeds the safety limit value and turned on, the diode unit DT1 and the resistance unit RT1 electrically coupled in series are coupled between the equipment ground GND1 and the control pilot terminal CP along with the temperature sensor ST1 or ST2 that is turned on, and then the high level and/or the low level of the control pilot signal Vcp4 is changed.

It is noted that the temperature sensor ST1, ST2 may be arranged in proper locations of the charge gun <NUM> to increase the sensitivity based on actual needs. In addition, the amounts of the temperature sensors, diode units, and resistance units are merely illustrated as examples to simplify the explanation, and do not intend to limit the present disclosure.

Reference is made to <FIG> is a flowchart illustrating an electric vehicle charging method <NUM> according to some embodiments of the present disclosure. For better understanding of the present disclosure, an electric vehicle charging method <NUM> is discussed in relation to the embodiments shown in <FIG>, but is not limited thereto. It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope of the disclosure. As shown in <FIG>, the electric vehicle charging method <NUM> includes steps S810, S820, S830, and S840.

At first, in step S810, the control circuit <NUM> controls the charge gun <NUM> to charge the electric vehicle <NUM> through the charging terminal P1-P3, PN according to the control pilot signal Vcp1. Next, in step S820, the temperature sensor ST1 is used to detect temperature of the charge gun <NUM>.

Next, in step S830, when the temperature sensor ST1 detects that the temperature of the charge gun <NUM> exceeds the safety limit value, the state of the temperature sensor is changed correspondingly, such that a positive level and/or a negative level of the control pilot signal c is switched from the first level to the second level. According to the present invention, the temperature sensor ST1 includes a temperature switch, and the temperature switch is turned off when the temperature of the charge gun <NUM> is lower than the safety limit value, and the temperature switch is turned on when the temperature of the charge gun <NUM> exceeds the safety limit value.

Next, in step S840, the control circuit <NUM> controls the charging device 100a to activate an over temperature protection according to the control pilot signal Vcp1 when the positive level or the negative level of the control pilot signal Vcp1 is at the second level. For example, in some embodiments, the control circuit <NUM> controls the charge gun <NUM> of the charging device 100a to stop charging the electric vehicle <NUM>. In some other embodiments, the control circuit <NUM> may also control the charging device 100a to lower the output to the electric vehicle <NUM>, or to output a warning signal, but the present disclosure is not limited thereto. One skilled in the art may perform various over temperature protections by properly arranging the control circuit <NUM>, in order to prevent the burnout of the elements and circuits in the system under high temperature and ensure the safety of the users.

Claim 1:
A charge gun (<NUM>) controlled by a control circuit (<NUM>), comprising:
at least one charging terminal (P1, P2, P3, PN) configured to be electrically coupled to an electric vehicle (<NUM>) to charge the electric vehicle;
a ground terminal (PE) electrically coupled to an equipment ground (GND2);
a control pilot terminal (CP) configured to transmit a control pilot signal (Vcp3) between the charge gun and the electric vehicle; and
an over temperature detecting circuit (142c) electrically coupled between the ground terminal and the control pilot terminal (CP), characterized in that:
wherein the over temperature detecting circuit (142c) comprises a temperature sensor (ST1) and a diode unit (DT1) connected in series, and the temperature sensor (ST1) is a temperature switch that is turned off when the temperature of the charge gun (<NUM>) is lower than the safety limit value, and is turned on when the temperature of the charge gun (<NUM>) exceeds the safety limit value, and
when the temperature of the charge gun (<NUM>) exceeds the safety limit value, the temperature sensor (ST1) is turned on and the diode unit (DT1) is in a forward period during a positive voltage level of the control pilot signal (Vcp3) to control the positive voltage level of the control pilot signal (Vcp3) to be switched from a first voltage level (VH1) to a second voltage level (VH2) different from the first voltage level (VH1), and
when the positive voltage level of the control pilot signal (Vcp3) is at the second voltage level (VH2), the control circuit (<NUM>) is configured to perform over temperature protections according to the control pilot signal (Vcp3).