Bidirectional ac charging device and method of operating the same

Abstract

A bidirectional alternating current charging device is coupled with a commercial power and an electric vehicle, and includes a power transmission path, a switch, a first controller, a communication unit, and a second controller. One end of the power transmission path is coupled with the commercial power through a first connection end, and the other end is coupled with the electric vehicle through a second connection end. The switch is configured on the power transmission path; the communication unit is coupled with the second connection end; and the first controller is coupled with the power transmission path, the switch, the second controller, and the communication unit. When the second controller receives a power demand request, the first controller is notified, the first controller switches from a first signal to a second signal to communicate with the electric vehicle and control the switch to be non-conductive, and after receiving a notification of allowing power feeding provided by the electric vehicle, the switch is controlled to be conductive. The present application also relates to an operating method of a bidirectional alternating current charging device.

Description

TECHNICAL FIELD

[0001] The present application relates to an alternating current charging device, and in particular to an alternating current charging device capable of bidirectional power supply and an operating method thereof. BACKGROUND

[0002] In recent years, due to the increasing awareness of environmental protection, government agencies actively promote energy-saving and carbon reduction policies, and the electric vehicle industry, which can significantly reduce air pollution, has therefore developed rapidly. With the increasing popularity of electric vehicles, the charging technology of electric vehicles has also gained increasing attention. For example Figure 1 As shown in the circuit block diagram of the conventional alternating current charging device, the conventional charging method of the electric vehicle using alternating current is to couple the commercial power 2 through the alternating current charging device 1', and physically couple the charging gun with the electric vehicle 3 to charge the electric vehicle 3. The conventional alternating current charging device 1' can usually only provide the commercial power P1 through the commercial power 2 to charge the electric vehicle 3 in one direction. During the charging process, the controller 16' communicates with the electric vehicle 3 using the communication unit 14 and controls the switch 20 to be turned on to provide a power transmission path for charging. However, due to the increasing demand for electricity, power companies are under pressure to balance the supply and demand of the power grid. In addition, the diversification of energy applications such as smart grids, renewable energy, and distributed energy has made the supply and demand of electricity no longer limited to one-way supply from the power generation end to the load end. Therefore, power companies must make more dynamic and flexible power dispatching according to the actual load demand, power cost and its cost performance. Therefore, the conventional one-way charging architecture of the commercial power 2 to the electric vehicle 3 cannot meet the demand of the above-mentioned flexible application of the power system.

[0003] Therefore, how to design a bidirectional alternating current charging device and an operating method thereof to provide a solution for bidirectional power supply between the commercial power and the alternating current charging type electric vehicle according to the actual power dispatching demand of the power system is a major research topic for the present inventors. SUMMARY

[0004] To solve the above problems, the present application provides a bidirectional AC charging device, which is coupled with a commercial power and an electric vehicle, and comprises: a power transmission path, one end of which is coupled with the commercial power through a first connection end, and the other end of which is coupled with the electric vehicle through a second connection end; a switch, which is arranged on the power transmission path; a first controller, which is coupled with the power transmission path and the switch; a second controller, which is coupled with the first controller and receives a power demand request; and a communication unit, which is coupled with the first controller and the second connection end. When the second controller receives the power demand request, the first controller is provided with a first notification, and the first controller communicates with the electric vehicle and controls the switch to be non-conductive after switching from a first signal to a second signal through the communication unit according to the first notification, and controls the switch to be conductive when the first controller receives a power feeding permission notification provided by the electric vehicle; and when the second controller receives a demand suspension request and correspondingly provides a second notification to the first controller, or when the first controller receives a power feeding suspension notification, the first controller controls the switch to be non-conductive and communicates with the electric vehicle after switching from the second signal to the first signal through the communication unit.

[0005] To solve the above problems, the present application provides a bidirectional AC charging device, which is coupled with a commercial power and an electric vehicle, and comprises: a power transmission path, one end of which is coupled with the commercial power through a first connection end, and the other end of which is coupled with the electric vehicle through a second connection end; a switch, which is arranged on the power transmission path; a first controller, which is coupled with the power transmission path and the switch; a second controller, which is coupled with the first controller and receives a power demand request; and a communication unit, which is coupled with the first controller and the second connection end. When the second controller receives the power demand request, the first controller is provided with a first notification, and the first controller communicates with the electric vehicle and controls the switch to be non-conductive after switching from a first signal to a second signal through the communication unit according to the first notification, and controls the switch to be conductive when the first controller receives a power feeding permission notification provided by the electric vehicle; and when the second controller receives a demand suspension request and correspondingly provides a second notification to the first controller, or when the first controller receives a power feeding suspension notification, the first controller controls the switch to be non-conductive and communicates with the electric vehicle after switching from the second signal to the first signal through the communication unit.

[0006] The main purpose and technical effect of the present application is that the first controller automatically controls the switch to be conductive or non-conductive according to whether the second controller receives the power demand request, the demand suspension request, and whether the first controller receives the power feeding permission notification and the power feeding suspension notification, so as to provide corresponding power supply directions according to the demand of the commercial power and the state of the electric vehicle, and thus the AC charging device of the present application achieves the technical effect of bidirectional power supply.

[0007] In order to further understand the technology, means and technical effects taken 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, and the drawings are provided for reference and illustration only, and are not used to limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 It is a circuit block diagram of a conventional charging device.

[0009] Figure 2 Circuit block diagram of the bidirectional AC charging device of the present invention;

[0010] Figure 3 Mode switching block diagram of the bidirectional AC charging device of the present invention;

[0011] Figure 4A Block diagram of the controller operating in the charging mode of the present invention;

[0012] Figure 4B Block diagram of the controller operating in the feeding mode of the present invention;

[0013] Figure 5A Flowchart of the mode setting operation method of the bidirectional AC charging device of the present invention; and

[0014] Figure 5B Flowchart of the protection mechanism method of the bidirectional AC charging device of the present invention.

[0015] Explanation of reference numerals:

[0016] 1’…charging device

[0017] 1…bidirectional AC charging device

[0018] 1A…first connection terminal

[0019] 1B…second connection terminal

[0020] 12…power transmission path

[0021] 14…communication unit

[0022] 16’…controller

[0023] 16A…first controller

[0024] 16B…second controller

[0025] 18…detection circuit

[0026] 182…first voltage detection unit

[0027] 184…current detection unit

[0028] 186…frequency detection unit

[0029] 188…residual current detection unit

[0030] 190…second voltage detection unit

[0031] 20…switch

[0032] 30…auxiliary power supply circuit

[0033] 30A first conversion circuit

[0034] 30B second conversion circuit

[0035] 2 mains

[0036] 2A mains management system

[0037] 3 electric vehicle

[0038] P1 mains power

[0039] T1 mains power transmission direction

[0040] P2 feed power

[0041] T2 feed power transmission direction

[0042] Vcc auxiliary power

[0043] Sc1 first signal

[0044] Sc2 second signal

[0045] N1 first notification

[0046] N2 second notification

[0047] NB feed allowed notification

[0048] NS feed aborted notification

[0049] NA charge allowed notification

[0050] RP power demand request

[0051] RS demand aborted request

[0052] CM charge mode

[0053] SM standby mode

[0054] BM feed mode

[0055] Sp power information signal

[0056] Sv1 first voltage signal

[0057] Sv2 second voltage signal

[0058] Si current signal

[0059] Sf frequency signal

[0060] Sir residual current signal

[0061] S100-S320 steps DETAILED DESCRIPTION

[0062] The technical content and detailed description of the present application are described as follows in conjunction with the accompanying drawings:

[0063] Please refer to Figure 2 The circuit block diagram of the bidirectional AC charging device is shown in FIG. 1. The bidirectional AC charging device 1 is coupled with the utility power 2, and is used to provide a power transmission path for charging the electric vehicle 3 by the utility power 2 or feeding the utility power 2 by the electric vehicle 3 according to the requirements of the electric vehicle 3 and the utility power 2 when the electric vehicle 3 is coupled with the bidirectional AC charging device 1. The electric vehicle 3 can be an electric vehicle, an electric motorcycle or other electrically driven vehicle. The bidirectional AC charging device 1 includes a power transmission path 12, a switch 20, a communication unit 14, a second controller 16B and a first controller 16A. The switch 20 is arranged on the power transmission path 12, and the switch 20 is controlled to be on or off to achieve the effect of turning on or cutting off the power transmission path 12. Moreover, one end of the power transmission path 12 is coupled with the utility power 2 through the power interface of the first connection end 1A, and the other end is coupled with the electric vehicle 3 through the power interface of the second connection end 1B. The coupling relationship makes the power transmission path 12 have a utility power transmission direction T1 from the first connection end 1A to the second connection end 1B for transmitting power (charging), and a feeding power transmission direction T2 from the second connection end 1B to the first connection end 1A for transmitting power (feeding).

[0064] The communication unit 14 is coupled with the first controller 16A, and is coupled with the electric vehicle 3 through the communication interface of the second connection end 1B. The communication unit 14 is used to provide a communication channel for the first controller 16A and the electric vehicle 3 to handshake information to know the current state and power requirement of each other. After the electric vehicle 3 is physically coupled with the bidirectional AC charging device 1, the first controller 16A and the electric vehicle 3 know the current state and power requirement of each other through the communication unit 14, so that the first controller 16A controls the bidirectional AC charging device 1 according to the decision after the communication with the electric vehicle 3 (provides the path for charging or feeding). The second controller 16B is connected with the utility management system 2A and the first controller 16A, and the second controller 16B can be a grid specification controller. The second controller 16B is used to communicate with the utility management system 2A to obtain the related information of the utility power, such as but not limited to the state of the utility power, such as voltage, current, frequency and power requirement of the utility power. When the utility management system 2A provides a power requirement request RP or a requirement suspension request to the second controller 16B according to the current utility peak load, supply and demand balance or the requirement of maintaining the quality of the grid, the second controller 16B provides a first notification to the first controller 16A according to the power requirement request RP, or provides a second notification to the first controller 16A according to the requirement suspension request, and the first controller 16A judges the switching of the switch 20 according to the type of the received notification.

[0065] In particular, the system behavior of the power flow being either from the utility 2 to the electric vehicle 3 for charging or from the electric vehicle 3 to the utility 2 for feeding can be generally distinguished by operation modes for the convenience of description, depending on the demand control of the switch 20 switching. According to an embodiment of the present application, the operation modes include a charging mode of turning on the switch 20 to provide the utility power PI from the first connection terminal 1A to the second connection terminal 1B through the power transmission path 12 (i.e. the utility power transmission direction Tl). The operation modes also include a feeding mode of turning on the switch 20 to provide the feeding power P2 from the second connection terminal 1B to the first connection terminal 1A through the power transmission path 12 (i.e. the feeding power transmission direction T2). In addition, the operation modes also include a standby mode of turning off the switch 20 to interrupt the power transmission path 12, resulting in no power transmission at present. The first controller 16A selects to operate in the feeding mode, the charging mode or the standby mode according to the decision of the first controller 16A after the handshake communication with the electric vehicle 3 in addition to the aforementioned notification types.

[0066] Further, when the electric vehicle 3 is physically coupled to the second connection terminal 1B, the first controller 16A is preset to transmit a first signal Sc1 to the electric vehicle 3 coupled to the second connection terminal 1B through the communication unit 14, which is a pulse width modulation (PWM) signal with a frequency of about 1 kHz according to the standard of the electric vehicle conductive charging specification (IEC 61851). When the electric vehicle 3 is physically coupled to the second connection terminal 1B, in addition to the preset transmission of the first signal Sc1 between the first controller 16A and the electric vehicle 3, if the second controller 16B receives a power demand request RP from the utility management system and provides a first notification to the first controller 16A, the first controller 16A and the electric vehicle 3 will use a second signal Sc2 different from the first signal Sc1 to communicate, such as but not limited to a pulse, a packet or a signal with a frequency different from the first signal Sc1. The first controller 16A transmits the information related to the power demand request RP (such as but not limited to the power demand power size of the current utility, the real power compensation demand value or the frequency correction demand value of the current utility, etc.) to the electric vehicle 3 through the second signal Sc2, and after the information handshake between the two parties on the power demand request RP is completed, the first controller 16A sets the operation mode to the standby mode and controls the switch 20 to be off to avoid any power transmission behavior at the moment. During the communication using the second signal Sc2, if the electric vehicle 3 judges that its own state and the state of the battery configured by it are normal and the power is sufficient to meet the demand content of the power demand request RP, it provides a feeding permission notification to the first controller 16A, which represents that the electric vehicle 3 allows to feed the power stored in itself back to the utility 2.

[0067] The aforementioned power feeding permission notification is provided to the first controller 16A by the communication interface and the communication unit 14 of the second connection 1B, so that the first controller 16A determines, according to the signal, that the electric vehicle 3 is allowed to feed the power stored therein back to the power grid 2, and sets the operation mode to the power feeding mode. Since the first controller 16A communicates with the electric vehicle 3 in the charging mode by using a PWM signal with a frequency of substantially 1 kHz, a signal with a frequency different from that of the first signal Sc1 is easy to implement in the communication application in the power feeding mode. For example, according to an embodiment of the present application, the second signal Sc2 is preferably a signal with a frequency higher than that of the first signal Sc1. In order to be obviously distinguished from the signal with a frequency of 1 kHz and easy to implement, the second signal Sc2 is preferably a signal with a frequency of 10 kHz. On the other hand, when the electric vehicle 3 is physically coupled to the second connection 1B, if the first controller 16A does not receive the power demand request RP from the power grid management system 2A, it means that the electric vehicle 3 does not need to operate in the power feeding mode. If the electric vehicle 3 has a charging demand and transmits the power feeding permission notification to the first controller 16A, the first controller 16A determines that the electric vehicle 3 has a charging demand and sets the operation mode to the charging mode.

[0068] Please refer to Figure 3 The mode switching block diagram of the bidirectional AC charging device of the present application is shown in FIG. 4, and please refer to Figure 2 According to an embodiment of the present application, the switching between the above-mentioned various modes, such as the switching from the charging mode CM to the power feeding mode BM, or between the power feeding mode BM and the charging mode CM, there is a standby mode SM. In the standby mode SM, the first controller 16A controls the switch 20 to be non-conductive, so that the power transmission path 12 is interrupted. In this way, the current flowing in an improper direction between the mode switching can be prevented, which can cause damage to the bidirectional AC charging device 1, the electric vehicle 3 or personnel. For example, when operating in the charging mode CM, the first controller 16A communicates with the electric vehicle 3 by using the first signal Sc1. If the power demand request RP is received from the power grid management system 2A, the second controller 16B provides the first notification N1 to the first controller 16A. The first controller 16A will first suspend the communication of the first signal Sc1, and use the second signal Sc2 to communicate with the electric vehicle 3. The information related to the power demand request RP is exchanged with the electric vehicle 3. When the information exchange related to the power demand request RP is completed, the first controller 12 switches the operation mode to the standby mode SM, and controls the switch 20 to be non-conductive, so that the power transmission path 12 is interrupted. After the first controller 16A confirms that the power transmission path 12 is interrupted, the first controller 16A switches to the power feeding mode BM only after the electric vehicle 3 provides the power feeding permission notification NB (in the format of the second signal Sc2), and controls the switch 20 to be conductive, so that the power feeding power P2 of the electric vehicle 3 is transmitted to the first connection 1A through the power transmission path 12 via the second connection 1B, and is supplied to the power grid 2.

[0069] On the contrary, when operating in the feeding mode BM, the first controller 16A communicates with the electric vehicle 3 via the second signal Sc2, if receiving a request of suspension of demand RS from the power management system 2A (the second controller 16B provides a second notification N2 to the first controller 16A), or receiving a notification of suspension of feeding NS from the electric vehicle 3 due to internal events (for example, but not limited to, electric vehicle system failure, battery failure or battery power shortage) (in the format of the second signal Sc2), the first controller 16A will first suspend the communication of the second signal Sc2, and switch the operation mode to the standby mode SM, and control the switch 20 to be non-conductive to interrupt the power transmission path 12, when confirming that the power transmission path 12 is interrupted, the first controller 16A will use the first signal Sc1 to communicate with the electric vehicle 3, and after the electric vehicle 3 provides a notification of permission of charging NA (in the format of the first signal Sc1), the first controller 16A will switch to the charging mode CM, and control the switch 20 to be conductive, so that the power P1 of the power supply 2 is transmitted from the first connection end 1A to the second connection end 1B via the power transmission path 12 to supply the electric vehicle 3.

[0070] Therefore, the first controller 16A can automatically switch to the feeding mode BM, the charging mode CM or the standby mode SM by receiving different power demand requests of the power management system 2A and judging the type of signals communicated with the electric vehicle 3, so that the first controller 16A can automatically switch to the feeding mode BM, the charging mode CM or the standby mode SM, instead of the prior art which only has a one-way charging control mode. Therefore, the corresponding power supply direction can be provided according to the demand of the electric vehicle 3, so that the alternating current charging device of the present application achieves the technical effect of bidirectional power supply. Figure 1

[0071] Referring to Figure 2 , the bidirectional alternating current charging device 1 further comprises a detection circuit 18 and a switch 20, and the detection circuit 18 and the switch 20 are coupled to the power transmission path 12 and the first controller 16A. The detection circuit 18 detects the power of the power transmission path 12 to generate a power information signal Sp, and the first controller 16A controls the switch 20 to be conductive or non-conductive according to the power information signal Sp to turn on or turn off the power transmission path 12. Specifically, the detection circuit 18 comprises a plurality of detection units, which can comprise a first voltage detection unit 182, a current detection unit 184, a frequency detection unit 186, a residual current detection unit 188 and a second voltage detection unit 190, etc. for detecting the power parameters on the power transmission path 12, and the detection units 182-190 are respectively coupled to the first controller 16A.

[0072] ​The first voltage detection unit 182 detects the voltage of the first path from the first connection terminal 1A to the switch 20 to generate a first voltage signal Sv1, and the second voltage detection unit 190 detects the voltage of the second path from the switch 20 to the second connection terminal 1B to generate a second voltage signal Sv2, wherein the first voltage signal Sv1 corresponds to the voltage of the power supply side and the second voltage signal Sv2 corresponds to the voltage of the electric vehicle side when the switch 20 is not conducting. The current detection unit 184 detects the current of the power transmission path 12 to generate a current signal Si, and the frequency detection unit 186 detects the frequency of the voltage and current of the power transmission path 12 to generate a frequency signal Sf. The residual current detection unit 188 detects the residual current of the power transmission path 12 to provide a residual current signal Sir. The power information signal Sp can include at least the first voltage signal Sv1, the second voltage signal Sv2, the current signal Si, the frequency signal Sf and the residual current signal Sir, and the first controller 16A determines whether to control the switch 20 to conduct or not to conduct the power transmission path 12 according to the above signals. Further, the first controller 16A can determine whether the power on the power transmission path 12 has overvoltage / undervoltage (OV / UV), overcurrent (OC), overfrequency / underfrequency (OF / UF) according to the first voltage signal Sv1, the second voltage signal Sv2, the current signal Si and the frequency signal Sf, and the residual current signal Sir can determine whether the leakage current between the power transmission path 12 and the ground terminal N occurs. When the above conditions do not occur, the first controller 16A controls the switch 20 to conduct, so that the power transmission path 12 is conducted. Otherwise, the switch 20 is controlled not to conduct, so that the power transmission path 12 is not conducted. The switch 20 can be a switch with two transistors in series or a relay, and can be a bidirectional on / off switch element.

[0073] Referring again to Figure 2The bidirectional AC charging device 1 further comprises an auxiliary power supply circuit 30 coupled to the internal system loads of the bidirectional AC charging device 1, such as but not limited to the first controller 16A, the communication unit 14, the switch 20, and other peripheral circuits or electronic components that need auxiliary power to operate, and the auxiliary power supply circuit 30 comprises a first conversion circuit 30A and a second conversion circuit 30B. The first conversion circuit 30A is coupled to two phases (for three-phase system or single-phase system) of the power transmission path 12, and the specific coupling position is preferably close to the first connection end 1A. The first conversion circuit 30A can be an existing AC-DC conversion circuit, such as but not limited to a flyback conversion circuit, a forward conversion circuit, etc. The first conversion circuit 30A converts the power on the power transmission path 12 into auxiliary power Vcc required for the internal system loads to operate, wherein the auxiliary power Vcc can be +15V, +12V, +5V and / or +3V, but is not limited thereto. The second conversion circuit 30B is coupled to two phases (for three-phase system or single-phase system) of the power transmission path 12, and the specific coupling position is preferably close to the second connection end 1B. The second conversion circuit 30B can also be an existing AC-DC conversion circuit, which converts the power on the power transmission path 12 into auxiliary power Vcc required for the internal system loads to operate, and the output end of the second conversion circuit 30B is connected in parallel with the output end of the first conversion circuit 30A.

[0074] In particular, one of the features of the bidirectional AC charging device 1 of the present application is that the auxiliary power Vcc required for the operation of the internal loads of the system can be supplied by the first conversion circuit 30A and / or the second conversion circuit 30B in different operation modes. When the first controller 16A operates in the charging mode CM, the mains power Pl can be converted into the auxiliary power Vcc required for the operation of the internal loads of the system by the first conversion circuit 30A or the second conversion circuit 30A due to the switch 20 being turned on, so that the first controller 16A can stably control the bidirectional AC charging device 1 in the charging mode CM. Similarly, when the bidirectional AC charging device 1 operates in the power feeding mode BM, the power feeding power P2 can be converted into the auxiliary power Vcc required for the operation of the internal loads of the system by the first conversion circuit 30A or the second conversion circuit 30A. However, when the first controller 16A operates in the standby mode SM, the switch 20 is not turned on, so that only one side of the mains 2 or the electric vehicle 3 can provide power. However, due to the design of the auxiliary power supply circuit 30 of the present application having double conversion circuits, the corresponding conversion circuit can convert the power provided by the side into the auxiliary power Vcc required for the operation of the internal loads of the system. Therefore, assuming that only the first conversion circuit 30A is available, and when the mains 2 fails and the first controller 16A operates in the power feeding mode, or when the standby mode SM enters the power feeding mode BM, but the switch 20 has not been turned on, the first controller 16A cannot obtain the auxiliary power Vcc required for operation, resulting in the failure of the bidirectional AC charging device 1 (and vice versa). Therefore, the addition of the second conversion circuit 30B enables the first controller 16A to successfully obtain the auxiliary power Vcc required for operation even when one side of the power fails.

[0075] Please refer to Figure 4A the block diagram of the controller of the present application operating in the charging mode, Figure 4B the block diagram of the controller of the present application operating in the power feeding mode, and please refer to Figures 2-3 . In Figure 4A the first controller 16A is preset to communicate with the electric vehicle 3 coupled to the second connection end IB through the communication unit 14 with the first signal Sc1, and after obtaining the permission to charge notification provided by the electric vehicle 3 through information handshake, the first controller 16A operates in the charging mode CM. Then, the first controller 16A controls the switch 20 of the bidirectional AC charging device 1 to be turned on, so that the mains power Pl provided by the mains 2 in the mains power transmission direction T1 can be transmitted from the first connection end 1A, the switch 20, and the second connection end IB to the electric vehicle 3.

[0076] In Figure 4BIn the embodiment, after the electric vehicle 3 physically couples the second connection terminal 1B, the controller 16A is preset to communicate with the electric vehicle 3 coupled to the second connection terminal 1B through the communication unit 14 with the first signal Sc1, wherein the second controller 16B is coupled to the power management system 2A to obtain the information of the power 2 through the power management system 2A, such as but not limited to the current voltage, current, frequency state of the power 2, and the power demand. If the second controller 16B receives the power demand request RP from the power management system 2A, and provides the first notification to the first controller 16A according to the power demand request RP, the first controller 16A will stop transmitting the first signal Sc1 with the electric vehicle 3, and instead communicate with the electric vehicle 3 with the second signal Sc2, and exchange the information related to the power demand request RP with the electric vehicle 3. After the information related to the power demand request RP is exchanged, the first controller operates in the standby mode SM, and the switch 20 is turned off to interrupt the power transmission path 12. If the first controller 16A receives the power feeding permission notification NB provided by the electric vehicle 3 through the communication unit 14, the first controller 16A switches to operate in the feeding mode BM. Wherein, Figure 3 The power feeding permission notification NB and the power feeding suspension notification NS are notified in the format of the second signal Sc2. Then, the first controller 16A determines the optimal time point for turning on the switch 20 according to the current power information provided by the second controller 16B; or the first controller 16A provides the current power information to the electric vehicle, and the electric vehicle determines the voltage and phase of the feeding power according to the power information, outputs the feeding power and notifies the first controller 16A, and then the first controller 16A controls the switch 20 to be turned on, so that the feeding power P2 in the transmission direction T2 provided by the electric vehicle 3 is transmitted from the second connection terminal 1B, the switch 20, the first connection terminal 1A to the power 2. Wherein, if the first signal Sc1 and the second signal Sc2 are different types of signals, different signal transmission lines can be used for transmission (as shown in Figure 4B When the first signal Sc1 and the second signal Sc2 are the same type of signal (for example, both are PWM signals, and the difference is only in the frequency), the same signal transmission line can be used for transmission, which can be adjusted according to the actual needs.

[0077] Please refer to Figure 5A The operation method flowchart for setting the mode of the bidirectional alternating current charging device of the present application, and in combination with Figures 2-4BThe method of operating the bidirectional AC charging device 1 comprises receiving a power demand request by the second controller (S100). The second controller 16B is connected between the utility management system 2A and the first controller 16A, and is configured to communicate with the utility management system 2A to obtain information related to the utility, such as but not limited to, the status of the utility and the power demand of the utility. Then, when the second controller receives the power demand request from the utility management system, the second controller notifies the first controller, so that the first controller communicates with the electric vehicle via the communication unit using a second signal different from the first signal after switching from the first signal to the second signal, and controls the power transmission path to be non-conductive (S120). When the utility management system 2A provides a power demand request RP to the second controller 16B according to the current balance of supply and demand of the utility, the second controller 16B provides a first notification to the first controller 16A according to the power demand request RP. After the first controller 16A receives the first notification, the first controller 16A and the electric vehicle 3 will use a second signal Sc2 different from the first signal Sc1 to communicate, such as but not limited to, a signal with a different pulse, packet or frequency from the first signal Sc1. After the first controller 16A communicates the information related to the power demand request RP with the electric vehicle, the first controller 16A controls the switch 12 on the power transmission path 12 to be non-conductive, so as to interrupt the power transmission path 12.

[0078] Then, when the first controller receives a power feeding permission notification provided by the electric vehicle, the power transmission path is controlled to be conductive (S140). During the communication using the second signal Sc2, if the electric vehicle 3 judges that its own state and the state of the battery configured by it are normal and the power is sufficient to allow power feeding, the electric vehicle 3 provides a power feeding permission notification to the first controller 16A, which represents that the electric vehicle 3 allows the power stored in itself to be fed back to the utility 2. The power feeding permission notification is provided to the first controller 16A through the communication interface of the second connection end 1B and the communication unit 14, so that the first controller 16A judges according to the signal that the electric vehicle 3 allows the power stored in itself to be fed back to the utility 2, sets the operation mode to the power feeding mode, and controls the switch 20 on the power transmission path 12 to be conductive, so as to conduct the power transmission path 20 and provide a path for the power to be transmitted from the electric vehicle to the utility.

[0079] Then, in the feeding mode, when the second controller receives a request for suspension of demand from the power management system, it notifies the first controller, so that the first controller communicates with the electric vehicle after switching from the second signal to the first signal through the communication unit, and controls the power transmission path to be non-conductive (S160); or in the feeding mode, when the first controller receives a notification of suspension of feeding from the electric vehicle, it communicates with the electric vehicle after switching from the second signal to the first signal through the communication unit, and controls the power transmission path to be non-conductive (S180). In step (S140), when operating in the feeding mode BM, the first controller 16A communicates with the electric vehicle 3 in the second signal Sc2, if the second controller 16B receives a request for suspension of demand RS from the power management system 2A, or the first controller 16A receives a notification of suspension of feeding NS from the electric vehicle 3, the first controller 16A switches from the second signal Sc2 to the first signal Sc1 to communicate with the electric vehicle 3, and enters the standby mode SM, controls the switch 20 on the power transmission path 12 to be non-conductive, to cut off the power transmission path 12.

[0080] Finally, in the standby mode, when the first controller receives a notification of permission to charge provided by the electric vehicle, it operates in the charging mode in which the power supply is provided from the power grid to the electric vehicle through the power transmission path (S200). After steps (S160) and (S180), when the first controller 16A enters the standby mode and confirms that the power transmission path 12 is interrupted, it continues to communicate with the electric vehicle 3 in the first signal Sc1, and after the electric vehicle 3 provides a notification of permission to charge NA, it switches to the charging mode CM, controls the switch 20 to be conductive, so that the power grid power PI of the power grid 2 is transmitted from the first connection end 1A to the second connection end 1B through the power transmission path 12 and supplied to the electric vehicle 3.

[0081] Please refer to Figure 5B For the flowchart of the protection mechanism method of the bidirectional alternating current charging device of the present application, please also refer to Figures 2-5AIn steps (S100) to (S200), the protection mechanism of the bidirectional AC charging device 1 is included, and the steps include detecting the power of the power transmission path to generate a power information signal (S300). The detection line 18 includes a plurality of detection units, which can include a first voltage detection unit 182, a current detection unit 184, a frequency detection unit 186, a residual current detection unit 188, and a second voltage detection unit 190, and other detection units for detecting power parameters on the power transmission path 12. The detection line 18 detects the power of the power transmission path 12 to generate a power information signal Sp, and the power information signal Sp can include at least a first voltage signal Sv1, a second voltage signal Sv2, a current signal Si, a frequency signal Sf, and a residual current signal Sir. Then, the first controller controls the power transmission path to be on or off according to the power information signal (S320). The first controller 16A can determine whether the power on the power transmission path 12 has an overvoltage / undervoltage (OV / UV), overcurrent (OC), and overfrequency / underfrequency (OF / UF) condition according to the first voltage signal Sv1, the second voltage signal Sv2, the current signal Si, and the frequency signal Sf, and the residual current signal Sir can determine whether the condition of the leakage current between the power transmission path 12 and the ground N occurs. When the above conditions do not occur, the first controller 16A controls the switch 20 to be on, so that the power transmission path 12 is on. Otherwise, the switch 20 is controlled to be off, so that the power transmission path 12 is off.

[0082] However, the above is only a detailed description of the preferred embodiments of the application and the accompanying drawings, and the features of the application are not limited thereto, and are not intended to limit the application. The scope of the application should be based on the following claims, and any embodiments that are similar to the concept of the claims and similar changes of the application should be included in the scope of the application. Any changes or modifications that can be easily thought of by those skilled in the art in the field of the application can be covered by the claims of the present disclosure.

Claims

1. A bidirectional alternating current charging device coupled with a power grid and an electric vehicle, comprising: a power transmission path having one end coupled with the power grid through a first connection terminal and the other end coupled with the electric vehicle through a second connection terminal; a switch disposed on the power transmission path; a first controller coupled with the power transmission path and the switch; a second controller coupled with the first controller and receiving a power demand request; and a communication unit coupled with the first controller and the second connection terminal; wherein when the second controller receives the power demand request, a first notification is provided to the first controller, the first controller correspondingly communicates with the electric vehicle through the communication unit and controls the switch to be non-conductive, and when the first controller receives an allowed power feeding notification, the first controller controls the switch to be conductive, wherein when the second controller receives a demand suspension request and correspondingly provides a second notification to the first controller, or when the first controller receives a suspension power feeding notification, the first controller controls the switch to be non-conductive, wherein when the first controller receives the first notification, the communication unit uses a second signal for communication, and when the first controller receives the second notification or the suspension power feeding notification, the communication unit uses a first signal different from the second signal for communication, and wherein the bidirectional alternating current charging device further comprises: an auxiliary power supply circuit including a first conversion circuit near the first connection terminal and a second conversion circuit near the second connection terminal, the first conversion circuit and / or the second conversion circuit converting a power on the power transmission path into an auxiliary power supply to the first controller, the auxiliary power supply being used for system internal load operation.

2. The bidirectional alternating current charging device of claim 1, further comprising: a detection circuit coupled with the power transmission path and the first controller and detecting a power on the power transmission path to generate a power information signal; wherein the first controller controls the switch to be conductive or non-conductive according to the power information signal.

3. The bidirectional alternating current charging device of claim 2, wherein the power transmission path includes a first path from the first connection terminal to the switch and a second path from the switch to the second connection terminal, and the detection circuit includes: a first voltage detection unit detecting a voltage of the first path to provide a first voltage signal; a frequency detection unit detecting a frequency of the power transmission path to provide a frequency signal; a current detection unit detecting a current of the power transmission path to provide a current signal; a residual current detection unit detecting a residual current of the power transmission path to provide a residual current signal; and a second voltage detection unit detecting a voltage of the second path to provide a second voltage signal; wherein the power information signal includes the first voltage signal, the frequency signal, the current signal, the residual current signal, and the second voltage signal. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 4. The bidirectional AC charging device of claim 3, wherein the first controller determines whether an overvoltage or an undervoltage occurs in the AC power supply according to the first voltage signal, and determines whether the overvoltage or the undervoltage occurs in the electric vehicle according to the second voltage signal; the first controller determines whether an overcurrent occurs in the power transmission path according to the current signal, and determines whether an overfrequency or an underfrequency occurs in the power transmission path according to the frequency signal, and determines whether a leakage current occurs in the power transmission path according to the residual current signal; when the overvoltage, the undervoltage, the overcurrent, the overfrequency, the underfrequency, or the leakage current occurs, the first controller controls the switch to be non-conductive.

5. An operating method of a bidirectional AC charging device, comprising the steps of: (a) receiving a power demand request by a second controller; (b) when the second controller receives the power demand request, notifying a first controller, so that the first controller communicates with an electric vehicle through a communication unit after switching from a first signal to a second signal different from the first signal, and controls a power transmission path to be non-conductive; (c) when the first controller receives a power feeding permission notification, controlling the power transmission path to be conductive; (d) when the second controller receives a demand suspension request, notifying the first controller, so that the first controller communicates with the electric vehicle through the communication unit after switching from the second signal to the first signal, and controls the power transmission path to be non-conductive; (d) when the first controller receives a power feeding suspension notification, communicating with the electric vehicle through the communication unit after switching from the second signal to the first signal, and controlling the power transmission path to be non-conductive, wherein the operating method further comprises: (e) converting a power on the power transmission path to an auxiliary power for the first controller through a first conversion circuit close to a first connection end of the power transmission path and / or a second conversion circuit close to a second connection end of the power transmission path, the auxiliary power being used for system internal load operation.

6. The operating method of claim 5, further comprising: detecting a power of the power transmission path to generate a power information signal; and the first controller controlling the power transmission path to be conductive or non-conductive according to the power information signal.

7. The operating method of claim 6, further comprising: when the first controller determines that the power occurs an overvoltage, an undervoltage, an overcurrent, an overfrequency, an underfrequency, or a leakage current according to the power information signal, controlling the power transmission path to be non-conductive. ​

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