Charging device and charging operation method thereof

Abstract

A charging device is used to charge an electric vehicle, and the charging device includes a first end, a second end, a switch unit, a control unit and a communication unit. The first end receives a power source, and the second end is coupled to the electric vehicle. The switch unit is used to be controlled to be turned on or turned off to control whether the first end is coupled to the second end. The control unit sets a first time at which the switch unit receives a control signal to actually actuate to be turned off or turned on, and transmits a communication signal with the electric vehicle through the communication unit. The control unit calculates a second time at which a current reaches zero based on the communication signal indicating an abnormal state, and calculates a time at which the switch unit is actuated at zero based on the first time and the second time to control the switch unit to be turned off at zero. The present application also relates to a charging operation method.

Description

Technical Field

[0001] The present invention relates to a charging device and a charging operation method thereof, and more particularly to a charging device with a zero current switching function and a charging operation method thereof. Background Art

[0002] As environmental awareness improves, more and more users are abandoning traditional fuel-powered vehicles and switching to rechargeable electric vehicles. As a result, the use of electric vehicles is becoming increasingly popular. Because of this, people's demand for charging stations is also increasing. Usually, a charging station is equipped with at least one charging device (commonly known as a charging pile) to provide users with charging needs to charge their electric vehicles. When an electric vehicle wants to charge, the charging device will confirm that there is an electric vehicle connected before controlling the internal relay to conduct, so as to avoid risks such as power leakage when not charging.

[0003] However, if Figures 1A and 1B As shown, current applications of charging devices lack optimized control over the timing of relay connection and switching. This can lead to relay switching occurring at the phase angle of maximum current I. Because the relay contains an internal coil, it is inherently an inductive load. If current I is present when the relay switches (i.e., during times tx and ty), the inductance resists the change in current I, generating a back electromotive force in the relay. This can cause sparking when the relay is connected, and the heat generated by this spark can easily cause the relay to stick.

[0004] Therefore, how to design a charging device and a charging operation method thereof to extend the life of the switch unit and prevent sparks from causing dangerous events is a major research topic that the inventors of the present disclosure want to conduct. Summary of the Invention

[0005] To solve the above problems, the present application provides a charging device with zero current switching function to overcome the problems of the prior art. Therefore, the charging device of the present application charges an electric vehicle, and the charging device includes a first end, a second end, a switching unit, a control unit and a communication unit. The first end receives a power source, and the second end is coupled to the electric vehicle. The switching unit is coupled to the first end and the second end, and is used to be controlled to turn on or turn off to control whether the first end is coupled to the second end. The control unit is coupled to the switching unit, and sets a first time at which the switching unit receives a control signal to actually actuate to turn off or turn on. The communication unit is coupled to the control unit and the second end, and the control unit transmits communication signals with the electric vehicle through the communication unit. Wherein, the control unit detects the phase of the current of the power source, and based on the communication signal indicating an abnormal state, calculates a second time at which the current reaches zero point through the phase. The control unit calculates a third time at which the switching unit is actuated at zero point based on the first time and the second time, and provides a control signal to control the switching unit to turn off at the third time.

[0006] To solve the above problems, the present application provides a charging device with zero current switching function to overcome the problems of the prior art. Therefore, the charging device of the present application charges an electric vehicle, and the charging device includes a first end, a second end, a switching unit, a control unit and a communication unit. The first end receives a power source, and the second end is coupled to the electric vehicle. The switching unit is coupled to the first end and the second end, and is used to be controlled to turn on or turn off to control whether the first end is coupled to the second end. The control unit is coupled to the switching unit, and sets a first time at which the switching unit receives a control signal to actually actuate to turn off or turn on. The communication unit is coupled to the control unit and the second end, and the control unit transmits communication signals with the electric vehicle through the communication unit. Wherein, the control unit detects the phase of the current of the power source, and based on the communication signal indicating an abnormal state, calculates a second time at which the current reaches zero point through the phase. The control unit calculates a third time at which the switching unit is actuated at zero point based on the first time and the second time, and provides a control signal to control the switching unit to turn off at the third time.

[0007] The main purpose and technical effect of the present application is that no matter whether the electric vehicle needs to be charged or fed or one of them occurs an abnormal state, the control unit will control the switching unit to actuate as close to zero point of the current of the power source as possible, so that when the switching unit is actuated, the current is low and is not easy to generate sparks or sticking problems, and the service life of the switching unit is prolonged and the danger of sparks is prevented.

[0008] In order to further understand the technology, means and technical effects adopted by the present application to achieve the predetermined purpose, please refer to the following detailed description and drawings of the present application. It is believed that the purpose, features and characteristics of the present application can be understood in depth and specifically from the above, however, the drawings are provided for reference and explanation only, and are not used to limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1AWaveform diagram of the on-time point of the existing relay;

[0010] Figure 1B Waveform diagram of the off-time point of the existing relay;

[0011] Figure 2 Circuit block diagram of the charging device with zero-current switching function of the present application;

[0012] Figure 3 Waveform diagram of the communication signal of the charging device of the present application;

[0013] Figure 4A Waveform diagram of the communication signal of the first embodiment of the charging device of the present application in the normal charging state;

[0014] Figure 4B Waveform diagram of the communication signal of the second embodiment of the charging device of the present application in the normal charging state;

[0015] Figure 5A Flowchart of the charging operation method of the charging device of the present application in the normal state; and

[0016] Figure 5B Flowchart of the protection operation method of the charging device of the present application in the abnormal state.

[0017] Explanation of reference numerals:

[0018] 100…charging device

[0019] 100A…first end

[0020] 100B…second end

[0021] 1…switching unit

[0022] L1…first path

[0023] L2…second path

[0024] 2…control unit

[0025] 22…controller

[0026] 24…detection unit

[0027] 242…first voltage detection unit

[0028] 244…current detection unit

[0029] 246…temperature detection unit

[0030] 248…second voltage detection unit

[0031] 252…leakage current detection unit

[0032] 254…Ground detection unit

[0033] 3…Communication unit

[0034] 200…Electric vehicle

[0035] Pin…Power source

[0036] V…voltage

[0037] I…current

[0038] Sc…control signal

[0039] Scom...communication signal

[0040] Sv1…first voltage signal

[0041] Sv2…second voltage signal

[0042] Si…current signal

[0043] St…temperature signal

[0044] Slc…leakage current signal

[0045] Ss…Detection signal

[0046] A1…first positive potential

[0047] A2…Pulse width modulation signal

[0048] B1…Second positive potential

[0049] B2…first pulse width modulation signal

[0050] C2…second pulse width modulation signal

[0051] C1…third positive potential

[0052] E…Zero potential

[0053] F…Negative potential

[0054] t1~t8、tx、ty…time

[0055] S100~S560…Steps DETAILED DESCRIPTION

[0056] The technical content and detailed description of the present invention are described as follows with reference to the accompanying drawings:

[0057] See also Figure 2This is a circuit block diagram of a charging device with a zero-current switching function according to the present invention. The charging device 100 receives a power source Pin to provide the power source Pin to an electric vehicle 200 (for example, but not limited to, a charging vehicle such as an electric car) to charge the electric vehicle 200. The charging device 100 includes a first end 100A and a second end 100B. The first end 100A receives the power source Pin, and the second end 100B is coupled to the electric vehicle 200. The second end 100B can be a charging gun for the charging device 100 to dock with the electric vehicle 200. The charging device 100 also includes a switch unit 1, a control unit 2, and a communication unit 3. One end of the switch unit 1 is coupled to the first end 100A, and the other end of the switch unit 1 is coupled to the second end 100B. The switch unit 1 is used to be controlled to be turned on or off to control whether the first end 100A is coupled to the second end 100B, so that the power source Pin is connected to the electric vehicle 200. When the switch unit 1 is controlled to be on, the power source Pin charges the electric vehicle 200 through the switch unit 1. Otherwise, the electric vehicle 200 cannot be charged. It is worth noting that in one embodiment of the present invention, the switch unit 1 may be a relay, and the charging device 100 may be a bidirectional charging device. In addition to providing the power source Pin to charge the electric vehicle 200, the electric vehicle 200 can also feed power to the charging device 100.

[0058] The control unit 2 is coupled to the switch unit 1 and provides a control signal Sc to control the switch unit 1 to be turned on or off. The communication unit 3 is coupled to the control unit 2 and the second end 100B, and the control unit 2 transmits a communication signal Scom to the electric vehicle 200 through the communication unit 3 to communicate with the electric vehicle 200. The communication unit 3 can be a control pilot circuit. The control unit 2 mainly communicates with the electric vehicle 200 through the control pilot circuit using a handshake protocol to learn each other's status and needs. Furthermore, the main purpose and technical effect of the present invention is that, regardless of whether the electric vehicle 200 needs to be charged / fed or one of them has an abnormal state, the control unit 2 will control the switch unit 1 to operate as close to zero as possible when the current I of the power source Pin is close to zero, so that when the switch unit 1 is operated, the current I is low and it is not easy to cause sparks or sticking problems, thereby extending the life of the switch unit 1 and preventing sparks from causing dangerous events.

[0059] In particular, the control unit 2 is configured to set a time (hereinafter referred to as a first time) for the mechanical delay action of the switching unit 1, which is mainly the time from when the switching unit 1 receives the control signal Sc to when the switching unit 1 actually acts to turn off or turn on. The first time can be preset based on the model of the switching unit 1 before the charging device 100 is shipped, or the first time can be set after the charging device 100 is shipped. Then, when the charging device 100 is running (including when the electric vehicle 200 has not been connected to the charging device 100 and is in a standby state, or when the electric vehicle 200 has been connected to the second end 100B), the control unit 2 detects the phase of the current I of the power source Pin to determine the time when the current I reaches zero. When one of the charging device 100 or the electric vehicle 200 is in an abnormal state, the other party is notified of the abnormal state through the communication signal Scom, so when the control unit 2 detects the abnormal state based on the communication signal Scom, the control unit 2 calculates the time when the current I reaches the nearest zero point from the current current (hereinafter referred to as a second time) based on the phase.

[0060] Then, the control unit 2 calculates the time (hereinafter referred to as a third time) when the switching unit 1 acts at zero based on the first time and the second time. The third time is mainly the time when the control unit 2 knows the second time when the current I reaches zero, and the time when the control unit 2 provides the control signal Sc in advance by the first time. In this way, the control unit 2 provides the control signal Sc to the switching unit 1 at the third time, so that the switching unit 1 can act (i.e., turn off in response to the abnormal state) when the switching unit 1 receives the control signal Sc and the mechanical delay after the switching unit 1 acts at the second time when the current I is close to zero. It is worth mentioning that the abnormal state will be further described below.

[0061] Similarly, when neither the charging device 100 nor the electric vehicle 200 is in an abnormal state, the communication signal indicates a normal state or indicates that the electric vehicle 200 is fully charged, the control unit 2 also controls the switching unit 1 to act at the second time. In particular, after the control unit 2 couples the second end 100B of the charging device 100 to the electric vehicle 200, and the communication signal Scom indicates a normal state, the control unit 2 can start to provide the power source Pin to charge the electric vehicle 200, the control unit 2 calculates the second time when the current I reaches the nearest zero point from the current current, and calculates the third time based on the first time and the second time to provide the control signal Sc to control the switching unit 1 at the third time, so that the switching unit 1 can turn on at the time when the current I is close to zero. On the other hand, when the control unit 2 indicates that the electric vehicle 200 is fully charged based on the communication signal Scom, the switching unit 1 can also be turned off at the time when the current I is close to zero. The details of the operation are not described here.

[0062] Referring again to Figure 2The control unit 2 includes a controller 22 and a detection unit 24, and the controller 22 can be a microcontroller unit (MCU). The controller 22 is coupled to the switching unit 1 and the communication unit 3, and the detection unit 24 is coupled to the controller 22. The controller 22 detects whether the charging device 100 is in an abnormal state through the detection unit 24, and communicates with the electric vehicle 200 through the communication unit 3 to know the status and requirements of each other. The controller 22 can also set a first time to provide a control signal Sc to control the switching unit 1 to act at an appropriate time (i.e. a third time) based on the overall status of the power source Pin, the charging device 100 and the electric vehicle 200 at present.

[0063] Further, the detection unit 24 includes a first voltage detection unit 242, a current detection unit 244, a temperature detection unit 246, a second voltage detection unit 248, a leakage current detection unit 252 and a ground detection unit 254. The first voltage detection unit 242 is coupled to the first path L1 between the first end 100A and the switching unit 1, and detects the voltage V of the power source Pin on the first path L1 to provide a first voltage signal Sv1 to the controller 22. The controller 22 knows the size of the voltage V on the first path L1 based on the first voltage signal Sv1, and judges whether an abnormal state of low voltage or overvoltage occurs. The current detection unit 244 is coupled to the first path L1, and detects the current I to provide a current signal Si to the controller 22. The controller 22 knows the size of the current I on the first path L1 based on the current signal Si, and judges whether an abnormal state of overcurrent occurs. The temperature detection unit 246 detects the temperature of the charging device 100 to provide a temperature signal St to the controller 22, and the controller 22 knows the high and low of the temperature based on the temperature signal St, and judges whether an abnormal state of overtemperature occurs. The temperature detection unit 246 can be usually configured on important elements such as but not limited to the controller 22 which are easy to heat, to monitor whether the elements such as the controller 22 are overheated.

[0064] The leakage current detection unit 252 is coupled to the first path L1 between the first terminal 100A and the switch unit 1, and detects the current I and provides a leakage current signal Slc to the controller 22, so that the controller 22 can determine whether an abnormal leakage current state has occurred based on the leakage current signal Slc. The leakage current detection unit 252 can be a residual current device (RCD), but is not limited to this. The ground detection unit 254 is coupled to the ground terminal GND of the charging device 100, and detects the ground terminal GND and provides a detection signal Ss to the controller 22, so that the controller 22 can determine whether an abnormal ground fault state has occurred based on the detection signal Ss. When the controller 22 determines that any of the abnormal states of low voltage, overvoltage, overcurrent, overtemperature, leakage current, and ground fault has occurred in the charging device 100 by receiving the signal provided by the detection unit 24, the controller 22 provides a positive potential communication signal Scom through the communication unit 3 to notify the electric vehicle 200, so that the electric vehicle 200 can perform corresponding actions.

[0065] The second voltage detection unit 248 is coupled to the second path L2 between the switch unit 1 and the second end 100B. It detects the voltage V of the power source Pin on the second path L2 and provides a second voltage signal Sv2 to the controller 22. The controller 22 determines the magnitude of the voltage V on the second path L2 based on the second voltage signal Sv2 and determines whether the switch unit 1 has experienced an abnormal state such as switch sticking or switch drive failure based on the first voltage signal Sv1 and the second voltage signal Sv2. The controller 22 primarily uses the first voltage signal Sv1 and the second voltage signal Sv2 to determine the voltage V on the front and rear paths of the switch unit 1 and whether the current operation of the switch unit 1 complies with the control signal Sc1. When the controller 22 determines that the switch unit 1 has experienced either an abnormal state such as switch sticking or switch drive failure by receiving the first voltage signal Sv1 and the second voltage signal Sv2, it notifies the electric vehicle 200 via the communication unit 3 with a negative communication signal Scom, causing the electric vehicle 200 to perform the corresponding operation. On the other hand, when an abnormal state occurs at the electric vehicle 200 end (for example, but not limited to, overvoltage, overcurrent, etc.), the electric vehicle 200 adjusts the communication signal Scom to zero potential to inform the charging device 100 of the abnormal state at the electric vehicle 200 end through the communication unit 3.

[0066] See also Figure 3 Schematic diagram of the waveform of the communication signal of the charging device of the present invention at each stage, please refer to Figure 2 .exist Figure 3In the figure, the time axis coordinates are only for the convenience of describing the waveform implementation of each stage of the communication signal Scom, and are not a complete charging process. At time t0~t1, the charging device 100 is in a standby state after being turned on. The charging device 100 provides a communication signal Scom of the first positive potential A1 to the second end 100B through the communication unit 3 to detect whether there is an electric vehicle 200 connected to the second end 100B. Among them, the first positive potential A1 can be a DC voltage of 12V. At time t1~t2, after the electric vehicle 200 is pulled out, the charging device 100 confirms the removal of the electric vehicle 200. The charging device 100 provides a pulse width modulation signal A2 (i.e., communication signal Scom) corresponding to the first positive potential A1 to the second end 100B through the communication unit 3. After confirming that the electric vehicle 200 has been pulled out, the charging device 100 adjusts the communication signal Scom back to the first positive potential A1 to return to the standby state. Among them, the pulse width modulation signal A2 can be a pulse of 12V plus 1Khz. At time t2~t3, the physical connection between the charging device 100 and the electric vehicle 200 is completed (that is, the charging gun has been inserted into the electric vehicle 200). The charging device 100 provides a communication signal Scom of a second positive potential B1 to the second end 100B through the communication unit 3 to inform the electric vehicle 200 that it is ready to establish a communication mechanism for the handshake agreement. The second positive potential B1 can be a DC voltage of 9V. At time t3~t4, the communication mechanism between the charging device 100 and the electric vehicle 200 has been established. The charging device 100 provides a first pulse width modulation signal B2 in response to the second positive potential B1 to the second end 100B through the communication unit 3 to learn about each other's status and needs. The first pulse width modulation signal B2 can be a pulse of 9V plus 1Khz.

[0067] At time t4 to t5, an abnormal state occurs at the end of the electric vehicle 200. The electric vehicle 200 adjusts the communication signal Scom to zero potential E to inform the charging device 100 of the abnormal state at the end of the electric vehicle 200 through the communication unit 3. The zero potential E can be a DC voltage of 0V. At time t5 to t6, the charging device 100 learns that the switch unit 1 has an abnormal state of switch sticking or switch drive failure. The controller 22 provides a communication signal Scom with a negative potential F through the communication unit 3 to notify the electric vehicle 200, so that the electric vehicle 200 performs corresponding actions. The negative potential F can be a DC voltage of negative 12V. At time t6 to t7, the charging device 100 determines the occurrence of any one of the abnormal states of low voltage, overvoltage, overcurrent, overtemperature, leakage current and ground fault by receiving the signal provided by the detection unit 24. The charging device 100 provides a communication signal Scom of a third positive potential C1 through the communication unit 3 to notify the electric vehicle 200, so that the electric vehicle 200 performs corresponding actions. The third positive potential C1 can be a DC voltage of 6V.

[0068] At time t7, the charging device 100 provides the power source Pin to the electric vehicle 200, and the electric vehicle 200 waits for the state of receiving the power source Pin. At time t7-t8, the charging device 100 provides the power source Pin to the electric vehicle 200. The charging device 100 provides the second pulse width modulation signal C2 in response to the third positive potential C1 to the second end 100B through the communication unit 3, and when the charging device 100 and the electric vehicle 200 do not have abnormal states during the charging process, the communication signal Scom is maintained at the second pulse width modulation signal B2. The second pulse width modulation signal C2 can be 6V plus 1Khz pulse. It is worth mentioning that in an embodiment of the present application, the potentials and the pulse width modulation signal frequencies described in the drawings are only illustrative, and the potentials and the frequencies will change according to the different models of the charging device 100 and the different brands of the electric vehicle 200, so the above values are not limited.

[0069] Please refer to Figure 4A the communication signal waveform diagram of the first embodiment of the charging device of the present application in the normal charging state, Figure 4B the communication signal waveform diagram of the second embodiment of the charging device of the present application in the normal charging state, please also refer to Figures 2-3 In Figure 4A , the electric vehicle 200 informs the charging device 100 through the communication unit 3 that the charging is completed. At time t0-t1, the charging device 100 is in standby state and provides the communication signal Scom of the first positive potential A1 to the second end 100B. When the electric vehicle 200 is connected and the physical connection between the charging device 100 and the electric vehicle 200 is completed (time t1), the charging device 100 starts to provide the communication signal Scom of the second positive potential B1 to the second end 100B. After the communication mechanism is established (time t2), the charging device 100 provides the first pulse width modulation signal B2 to the second end 100B to communicate with the electric vehicle 200 to know the state and demand of each other.

[0070] After the charging device 100 and the electric vehicle 200 complete the communication with each other (time t3), the charging device 100 can start charging the electric vehicle 200, so the charging device 100 provides a second pulse width modulation signal C2 to the second end 100B. At this time, the control unit 2 calculates the second time when the current I reaches the nearest zero point from the current current, and calculates the third time through the second time and the preset first time, so as to provide a control signal Sc at the third time to control the switch unit 1 so that the switch unit 1 can be turned on just when it is close to zero point (i.e. time tx). Among them, time t3~t4 is the standard connection time of the switch unit 1. The switch unit 1 must be connected within 3 seconds of the electric vehicle standard of, for example but not limited to, IEC 61851-1. After calculating the third time, the charging device 100 can control the switch unit 1 to connect within this standard time.

[0071] After the electric vehicle 200 confirms that charging is complete (time t5), the electric vehicle 200 adjusts the second pulse width modulation signal C2 to the first pulse width modulation signal B2 to inform the charging device 100 that charging is complete. At this time, the control unit 2 also calculates the third time to provide the control signal Sc at the third time to control the switch unit 1 so that the switch unit 1 can be turned off just when it is close to zero (i.e., time ty). Among them, time t5~t6 is also the standard disconnection time of the switch unit 1. Then, after the electric vehicle 200 is physically disconnected from the charging device 100 (time t7), the charging device 100 confirms the withdrawal of the electric vehicle 200 and provides the pulse width modulation signal A2 to the second end 100B (time t7~t8), and returns to the standby state after confirming the withdrawal and provides the communication signal Scom of the first positive potential A1 (time t8).

[0072] exist Figure 4B In the embodiment, the electric vehicle 200 is directly withdrawn without informing the charging device 100 that charging is complete (ie, it is withdrawn before being fully charged). Figure 4A , Figure 4B and Figure 4A The difference is that there is no stage from time t5 to t7. After the charging device 100 detects that the electric vehicle 200 is physically disconnected at time t7, the charging device 100 begins to confirm the removal of the electric vehicle 200 and provides a pulse-width modulation signal A2 to the second end 100B, and provides a control signal Sc to control the switch unit 1 at a third time, so that the switch unit 1 can be turned off just at a time close to zero (real time ty). Among them, time t7 to t8 is also the standard disconnection time of the switch unit 1. After time t8, the charging device 100 confirms the removal of the electric vehicle 200 and provides a pulse-width modulation signal A2 to the second end 100B.

[0073] See also Figure 5AThis is a charging flow chart of the charging operation method of the charging device of the present invention under normal conditions, Figure 5B This is a protection flow chart of the charging operation method of the charging device of the present invention under abnormal conditions, and is also referred to in conjunction with Figures 2-4B .exist Figure 5A The steps S100 to S280 described in Figure 4A , I will not elaborate on this. Figure 5B Steps S300 to S460 described above represent implementations for various abnormal conditions. When each abnormal condition occurs, the communication signal Scom is adjusted to a signal corresponding to the abnormal condition. Therefore, in step S240, upon confirming the occurrence of any of the abnormal conditions in steps S300 to S460, the control unit 2 of the charging device 100 calculates a second time (S500) for the current I to reach the nearest zero point from the current current. The control unit 2 calculates a third time (S520) based on the second time and the predetermined first time. At the third time, the control signal Sc is provided to control the switch unit 1 (S540), enabling the switch unit 1 to be turned off precisely when the current is near zero. After the control unit 2 controls the switch unit 1 to turn off, the abnormality is corrected (S560), and the process returns to step S100.

[0074] However, the above description is only a detailed description and drawings of the preferred specific embodiments of the present invention, and the features of the present invention are not limited thereto and are not intended to limit the present invention. The full scope of the present invention should be based on the claims. All embodiments that are consistent with the concepts of the claims of the present invention and similar variations thereof should be included in the scope of the present invention. Any changes or modifications that can be easily thought of by any person skilled in the art within the field of the present invention can be covered by the claims of this disclosure.

Claims

1. A charging device for charging an electric vehicle, the charging device comprising: a first end receiving a power source; a second end coupled to the electric vehicle; a switch unit coupled to the first end and the second end, and configured to be controlled to be turned on or off to control whether the first end is coupled to the second end; a control unit coupled to the switch unit and configured to set a first time period from when the switch unit receives a control signal to when it is actually actuated to be turned off or on; and a communication unit coupled to the control unit and the second end, and the control unit transmits a communication signal to the electric vehicle via the communication unit; The control unit detects a phase of a current of the power source and indicates an abnormal state based on the communication signal, and calculates a second time when the current reaches a zero point through the phase; the control unit calculates a third time when the switch unit is actuated at the zero point based on the first time and the second time, and provides the control signal at the third time to control the switch unit to be turned off.

2. The charging device as described in claim 1, wherein the control unit calculates the second time through the phase based on the electric vehicle being coupled to the second end and the communication signal indicating a normal state, and calculates the third time based on the first time and the second time, so as to provide the control signal at the third time to control the switching unit to be turned on.

3. The charging device as claimed in claim 1 , wherein the control unit calculates the second time according to the phase based on the communication signal indicating that charging is complete, and calculates the third time based on the first time and the second time, so as to provide the control signal at the third time to control the switch unit to turn off.

4. The charging device as claimed in claim 1, wherein the control unit comprises: a controller coupled to the switch unit and the communication unit and configured to set the first time; and a detection unit coupled to the controller, and the controller detects whether the charging device has the abnormal state through the detection unit; The controller is configured to provide the control signal to control the switch unit at the third time based on the communication signal.

5. The charging device as claimed in claim 4, wherein the detection unit comprises: a first voltage detection unit coupled to the first end and between the switch unit, and detecting a voltage of the power source to provide a first voltage signal; a current detection unit coupled to the first terminal and between the switch units, and detecting the current to provide a current signal; and a temperature detection unit for detecting a temperature of the charging device and providing a temperature signal; In which, the controller determines whether an abnormal state of low voltage or overvoltage occurs based on the first voltage signal, determines whether an abnormal state of overcurrent occurs based on the current signal, and determines whether an abnormal state of overtemperature occurs based on the temperature signal; the controller provides a communication signal with a positive potential through the communication unit based on the abnormal state of any one of the low voltage, the overvoltage, the overcurrent and the overtemperature.

6. The charging device as claimed in claim 5, wherein the detection unit comprises: a second voltage detection unit coupled between the switch unit and the second end, and detecting the voltage to provide a second voltage signal; The controller determines whether the switch unit has an abnormal state of switch sticking or switch drive failure based on the first voltage signal and the second voltage signal, and provides a communication signal with a negative potential through the communication unit based on the abnormal state of either switch sticking or switch drive failure.

7. The charging device as claimed in claim 4, wherein the detection unit comprises: a leakage current detection unit coupled to the first terminal and between the switch units, and detecting the current to provide a leakage current signal; and a ground detection unit for detecting a ground terminal of the charging device and providing a detection signal; The controller determines whether an abnormal state of leakage current occurs based on the leakage current signal, and determines whether an abnormal state of ground fault occurs based on the detection signal; the controller provides a communication signal with a positive potential through the communication unit based on the abnormal state of either the leakage current or the ground fault.

8. The charging device as claimed in claim 1, wherein the control unit is aware that the electric vehicle has the abnormal state based on the communication signal being at a zero potential.

9. A charging method, wherein a charging device provides a power source to charge an electric vehicle, wherein the charging device includes a switch unit and a communication unit; the switch unit is controlled to be turned on or off to control whether the power source is coupled to the electric vehicle, and the charging method includes the following steps: Setting a first time from when the switch unit receives a control signal to when it is actually actuated to be turned off or on, and detecting a phase of a current of the power source; Transmitting a communication signal between the communication unit and the electric vehicle, and confirming whether the communication signal indicates an abnormal state; Calculating a second time when the current reaches a zero point through the phase based on the abnormal state; and A third time for the switch unit to be actuated at the zero point is calculated based on the first time and the second time, and the control signal is provided at the third time to control the switch unit to be turned off.

10. The charging operation method according to claim 9, further comprising the following steps: Calculating the second time using the phase based on the electric vehicle being physically coupled and the communication signal indicating a normal state; and The third time is calculated based on the first time and the second time, so as to provide the control signal at the third time to control the switch unit to be turned on.

11. The charging operation method according to claim 10, further comprising the following steps: Setting the communication signal to a first positive potential based on a standby state; confirming that the electric vehicle is physically coupled, setting the communication signal to a second positive potential, and providing the second positive potential to the electric vehicle; Adjusting the second positive potential to a first pulse width modulation signal responsive to the second positive potential based on establishing a communication relationship between the electric vehicle and the communication unit; and The first pulse width modulation signal is adjusted to a second pulse width modulation signal responsive to a third positive voltage based on the electric vehicle waiting to receive the power source to indicate a normal state.

12. The charging operation method according to claim 11, further comprising the following steps: Based on the communication signal being set from the second pulse width modulation signal to the first pulse width modulation signal to indicate a charging completion, calculating the second time by the phase; and Calculating the third time based on the first time and the second time, and providing the control signal at the third time to control the switch unit to be turned off; The communication signal is set to a first positive potential signal to adjust back to the standby state.

13. The charging operation method according to claim 9, further comprising the following steps: detecting a voltage provided by the power source to the switch unit path and providing a first voltage signal; detecting the current and providing a current signal; detecting a temperature of the charging device and providing a temperature signal; determining whether an abnormal state of low voltage or overvoltage occurs based on the first voltage signal, determining whether an abnormal state of overcurrent occurs based on the current signal, and determining whether an abnormal state of overtemperature occurs based on the temperature signal; and The communication signal is set to a third positive potential based on the abnormal state of any one of the low voltage, the overvoltage, the overcurrent and the overtemperature.

14. The charging operation method according to claim 13, further comprising the following steps: detecting the voltage of the path from the switch unit to the electric vehicle and providing a second voltage signal; Determining whether the switch unit has an abnormal state of switch sticking or switch drive failure based on the first voltage signal and the second voltage signal; and The communication signal is set to a first negative potential based on the abnormal state of either the switch sticking or the switch driving failure.

15. The charging operation method according to claim 9, further comprising the following steps: detecting the current and providing a leakage current signal; detecting a ground terminal of the charging device and providing a detection signal; Determining whether the abnormal state of a leakage current occurs based on the leakage current signal, and determining whether the abnormal state of a ground fault occurs based on the detection signal; and The communication signal is set to a third positive potential based on the abnormal state of either the leakage current or the ground fault.

16. The charging operation method according to claim 9, further comprising the following steps: The abnormal state of the electric vehicle is known based on the communication signal being set to a zero potential.

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