Detection circuit and power supply device for three-phase alternating current system

Abstract

The invention discloses a detection circuit and a power supply device for a three-phase alternating current system. The detection circuit used for the three-phase AC system comprises a driving circuit used for receiving an enable signal and generating a driving signal based on the enable signal; comprising a null line signal input end and a plurality of live line signal input ends, and is coupled with a null line relay of the AC system through the null line signal input end to receive a null line output signal of an output end of the null line relay; and a plurality of live line signal inputs coupled to a plurality of live line relays of the AC system to receive live line output signals of output terminals of the plurality of live line relays. The detection signal generation circuit is electrically coupled with the driving circuit through a plurality of live wire signal input ends, and generates a detection signal based on the live wire output signal and the zero wire output signal or the driving signal to indicate whether the AC system has a fault or not; the detection signals comprise a plurality of live wire detection signals corresponding to the plurality of live wire relays and a null line detection signal corresponding to the null line relay.

Description

Technical Field

[0001] This application relates to the field of three-phase AC systems, and more particularly, to a detection circuit and a power supply device for a three-phase AC system. Background Art

[0002] In the application of three-phase alternating current (AC) charging piles, the start or end of the charging process from the AC charging pile to an electric device such as an electric vehicle can be achieved by controlling the closing or opening of a relay in the three-phase AC system. Such a control method controls the high-voltage circuit by using a low-voltage signal to control the operation of the relay, ensuring safe, accurate, and efficient charging operations. However, there may be faults in the three-phase AC system. For example, when attempting to open multiple live wire relays or neutral wire relays to stop the charging process, the relay may not fully open (e.g., adhesion occurs). This may cause the AC charging pile to fail to switch the working state normally, thus affecting the stability and reliability of the charging pile. Another example is that there may be short-circuit faults between the output terminals of the live wire relays with each other, between the output terminal of the live wire relay and the output terminal of the neutral wire relay, and between the output terminal of the live wire relay and the ground. This may damage or burn the electronic components inside the charging pile, and even cause safety hazards such as electric shock and burns. Summary of the Invention

[0003] It should be understood that the above general description and the following detailed description of the present invention are both exemplary and explanatory, and are intended to provide further explanation of the present invention as claimed.

[0004] According to one aspect of the present invention, there is provided a detection circuit for a three-phase AC system, including a driving circuit configured to receive an enabling signal and generate a driving signal based on the enabling signal; and a detection signal generation circuit including a neutral wire signal input terminal and a plurality of live wire signal input terminals. The detection signal generation circuit is electrically coupled to the output terminal of the neutral wire relay of the AC system through the neutral wire signal input terminal to receive a neutral wire output signal from the output terminal of the neutral wire relay, and is electrically coupled to the output terminals of a plurality of live wire relays of the AC system through the plurality of live wire signal input terminals to receive live wire output signals from the output terminals of the plurality of live wire relays. Wherein, the detection signal generation circuit is electrically coupled to the output terminal of the driving circuit through the plurality of live wire signal input terminals, and is configured to generate a detection signal based on the live wire output signal and the neutral wire output signal, or based on the driving signal, to indicate whether there is a fault in the AC system. The detection signal includes a plurality of live wire detection signals corresponding to the plurality of live wire relays and a neutral wire detection signal corresponding to the neutral wire relay.

[0005] In the above detection circuit, a control circuit is further included, and the control circuit is configured to: deactivate the drive circuit and indicate whether there is a first fault in the AC system based on a detection signal, wherein the detection signal generation circuit is configured to generate the detection signal based on the live wire output signal and the neutral wire output signal; or activate the drive circuit and indicate whether there is a second fault in the AC system based on the detection signal, wherein the detection signal generation circuit is configured to generate the detection signal based on the drive signal.

[0006] In the above detection circuit, the drive circuit includes: a drive signal generation circuit configured to receive an enable signal and generate a drive signal based on the enable signal; and a first isolation circuit including a plurality of isolation switches, one ends of the plurality of isolation switches are respectively electrically coupled to an output end of the drive signal generation circuit, and the detection signal generation circuit is respectively electrically coupled to the other ends of the plurality of isolation switches via the plurality of live wire signal input ends.

[0007] In the above detection circuit, the drive circuit includes: a plurality of drive signal generation circuits, each of the plurality of drive signal generation circuits is respectively configured to receive an enable signal and generate a drive signal based on the enable signal; and a second isolation circuit including a plurality of isolation capacitors, one ends of the plurality of isolation capacitors are respectively electrically coupled to output ends of the plurality of drive signal generation circuits, and the detection signal generation circuit is respectively electrically coupled to the other ends of the plurality of isolation capacitors via the plurality of live wire signal input ends.

[0008] In the above detection circuit, the detection circuit further includes an isolated power supply module configured to isolate a power supply signal to generate an isolated power supply signal, and the plurality of drive signal generation circuits are configured to be powered by the isolated power supply signal.

[0009] In the above detection circuit, the control circuit is configured to: open all of the plurality of isolation switches to deactivate the drive circuit; or provide an enable signal to the drive signal generation circuit and close a selected one of the plurality of isolation switches to activate the drive circuit.

[0010] In the above detection circuit, the control circuit is configured to: isolate output signals of the plurality of drive signal generation circuits by the second isolation circuit to deactivate the drive circuit; or provide an enable signal to a selected one of the plurality of drive signal generation circuits to activate the drive circuit.

[0011] In the above detection circuit, the control circuit is configured to: place the drive circuit in the deactivation mode; determine whether the level of each of the detection signals is a first level; if it is determined that the level of each of the detection signals is the first level, indicate that the first fault does not exist in the AC system; if it is determined that the level of at least one of the detection signals is a second level, indicate that the first fault exists in the AC system.

[0012] In the above detection circuit, the control circuit is configured to: place the drive circuit in the activation mode; determine whether the level of the selected detection signal corresponding to the selected isolation switch among the detection signals is a second level and the levels of the remaining detection signals are first levels; if it is determined that the level of the selected detection signal is the second level and the levels of the remaining detection signals among the detection signals are the first levels, indicate that the second fault does not exist at the output end of the live wire relay corresponding to the selected detection signal.

[0013] In the above detection circuit, the control circuit is configured to: place the drive circuit in the activation mode; determine whether the level of the selected detection signal corresponding to the selected drive signal generation circuit among the detection signals is a second level and the levels of the remaining detection signals are first levels; if it is determined that the level of the selected detection signal is the second level and the levels of the remaining detection signals among the detection signals are the first levels, indicate that the second fault does not exist at the output end of the live wire relay corresponding to the selected detection signal.

[0014] In the above detection circuit, the control circuit is configured to: if it is determined that the level of the selected detection signal is the first level, or if it is determined that the level of the selected detection signal is the second level and the level of any one of the remaining detection signals among the detection signals is the second level, indicate that the second fault exists in the AC system.

[0015] In the above detection circuit, the control circuit is configured to: if it is determined that the level of the selected detection signal is the first level, indicate that there is a live-to-ground short circuit at the output end of the live wire relay corresponding to the selected detection signal; if it is determined that the level of the selected detection signal is the second level and the level of any one of the remaining detection signals among the detection signals is the second level, indicate that there is a phase-to-phase short circuit between the output end of the live wire relay corresponding to the selected detection signal and the relay corresponding to the remaining detection signal having the second level.

[0016] In the above detection circuit, the enable signal is a pulse width modulation (PWM) signal.

[0017] According to another aspect of the present invention, there is provided a power supply device, comprising: a plurality of live wire relays and neutral wire relays disposed on the live wire and the neutral wire in a three-phase AC system; and a detection circuit as described in any one of the above detection circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention can be better understood by describing exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0019] Figure 1 A schematic diagram showing the connection of a plurality of live wire relays and neutral wire relays for a three-phase AC system is shown;

[0020] Figure 2 A block diagram of a detection circuit for a three-phase AC system according to an embodiment of the present invention is shown;

[0021] Figure 3 A block diagram of a detection circuit for a three-phase AC system according to another embodiment of the present invention is shown;

[0022] Figure 4 A schematic connection diagram of a detection circuit for a three-phase AC system according to an embodiment of the present invention is shown;

[0023] Figure 5A A flowchart of operations performed by a control circuit according to an embodiment of the present invention is shown;

[0024] Figure 5B A flowchart of operations performed by a control circuit according to another embodiment of the present invention is shown;

[0025] Figure 6 A block diagram of a detection circuit for a three-phase AC system according to yet another embodiment of the present invention is shown;

[0026] Figure 7 A schematic connection diagram of a detection circuit for a three-phase AC system according to another embodiment of the present invention is shown;

[0027] Figure 8 A schematic connection diagram of a detection circuit for a three-phase AC system according to yet another embodiment of the present invention is shown;

[0028] Figure 9A A flowchart of operations performed by a control circuit according to yet another embodiment of the present invention is shown;

[0029] Figure 9B A flowchart of operations performed by a control circuit according to still another embodiment of the present invention is shown; and

[0030] Figure 10 The block diagram of a power supply device according to an embodiment of the present invention is shown. Detailed implementation manners

[0031] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, the present invention is not limited thereto but is only defined by the claims. In the drawings, for illustrative purposes, the dimensions of some of the elements may be enlarged and not drawn to scale. Whenever possible, the same reference numerals will be used throughout all the drawings to represent the same or similar parts.

[0032] Although the terms used in the present invention are selected from well-known and commonly used terms, some of the terms mentioned in the specification of the present invention may be selected by the applicant according to his or her judgment, and their detailed meanings are described in the relevant parts of the description herein. In addition, it is required to understand the present invention not only by the actual terms used, but also by the meaning implied by each term.

[0033] In the description provided herein, numerous specific details are set forth. However, it should be understood that embodiments of the present invention may be practiced without these specific details. In other instances, well-known methods, structures, and technologies have not been shown in detail so as not to obscure the understanding of the present invention.

[0034] Figure 1 A schematic diagram showing the connection of a plurality of line relays and neutral line relays for a three-phase alternating current (AC) system is shown. The plurality of line relays and neutral line relays are arranged in the main circuit of the AC charging pile. The input ends of the plurality of line relays and neutral line relays receive L1_IN, L2_IN, L3_IN, and N_IN signals from the live wire and the neutral line respectively. When it is necessary to start the charging process, the plurality of line relays and neutral line relays are closed, so that the L1_IN, L2_IN, L3_IN, and N_IN signals can flow through each of the plurality of line relays and neutral line relays respectively, and are output as L1_OUT, L2_OUT, L3_OUT, and N_OUT signals at the corresponding output ends; when it is necessary to stop the charging process, the plurality of line relays and neutral line relays are disconnected, so that the L1_IN, L2_IN, L3_IN, and N_IN signals cannot flow through.

[0035] However, if faults such as adhesion occur in the line relays and neutral line relays, it may cause the device including the above-mentioned relays to be energized, posing safety hazards such as electric shock, and even accelerating the aging and performance degradation of the components associated with the device, affecting the service life of the device. Moreover, during the charging process for the device to be charged, excessive impact may be generated, thereby causing damage to the device to be charged, etc.

[0036] In addition, if faults such as short circuits occur between the output terminals of the live wire relay, between the output terminal of the live wire relay and the output terminal of the neutral wire relay, or between the output terminal of the live wire relay and the ground, it may cause a sharp increase in current. When faults such as short circuits occur, the large current generated releases a large amount of heat in a short time, and even causes arc sparks, further leading to greater electrical safety risks.

[0037] Therefore, it is necessary to detect whether there are faults (such as relay adhesion, short circuits, etc.) in the three-phase AC system under appropriate scenarios.

[0038] In view of the above problems, the present application proposes a detection circuit for a three-phase AC system.

[0039] Figure 2 The block diagram of a detection circuit 200 for a three-phase AC system according to an embodiment of the present invention is shown. The detection circuit 200 may include a drive circuit 202 and a detection signal generation circuit 204.

[0040] The drive circuit 202 may be configured to receive an enable signal and generate a drive signal based on the enable signal.

[0041] In one embodiment, the enable signal may be a Pulse Width Modulation (PWM) signal. For example, the PWM signal may have a level such as 5V, 3.3V, etc. Again, for example, the PWM signal may have a frequency such as 5kHz, 10kHz, etc.

[0042] In one embodiment, the drive signal may be a PWM signal generated by the drive circuit adjusting the above enable signal. For example, the drive signal may have a level such as 24V, 12V, etc. Again, for example, the drive signal may have a frequency such as 5kHz, 10kHz, etc.

[0043] The detection signal generation circuit 204 may include a neutral line signal input terminal and a plurality of live line signal input terminals. The detection signal generation circuit 204 may be electrically coupled to the output terminal of the neutral line relay of the AC system via the neutral line signal input terminal to receive the neutral line output signal N_OUT from the output terminal of the neutral line relay. The detection signal generation circuit 204 may be electrically coupled to the output terminals of a plurality of live line relays of the AC system via the plurality of live line signal input terminals respectively to receive the live line output signals L1_OUT, L2_OUT, and L3_OUT from the output terminals of the plurality of live line relays. The detection signal generation circuit 204 may be electrically coupled to the output terminal of the drive circuit 202 via the plurality of live line signal input terminals, and is configured to generate a detection signal based on the live line output signals L1_OUT, L2_OUT, L3_OUT and the neutral line output signal N_OUT, or based on the drive signal to indicate whether there is a fault in the AC system. The detection signal may include a plurality of live line detection signals corresponding to the plurality of live line relays and a neutral line detection signal corresponding to the neutral line relay.

[0044] By adopting the above-described manner in which the detection signal generation circuit is electrically coupled to the output terminals of the plurality of live line relays, the neutral line relay, and the drive circuit, the detection signal generation circuit can not only indicate whether there is a fault in the AC system based on the live line output signal and the neutral line output signal, but also indicate whether there is a fault in the AC system based on the drive signal, thereby realizing the multiplexing of the detection signal generation circuit. In addition, this meets the detection requirements for various fault types without designing an independent detection circuit for each fault type, significantly improving the versatility of the circuit and enabling it to flexibly handle various fault types that may occur in a three-phase AC system. Further, such a design effectively simplifies the circuit structure, reduces the occupied space and manufacturing cost, and avoids the complex connection and potential interference problems between multiple independent circuits, improving the robustness and reliability of the system.

[0045] In one embodiment, the faults existing in the AC system may include a first fault and a second fault. The first fault may include a fault caused by the adhesion of the live line relay and / or the neutral line relay. The second fault may include a fault caused by a short circuit between the output terminals of the live line relays, between the output terminal of the live line relay and the output terminal of the neutral line relay, or between the output terminal of the live line relay and the ground.

[0046] In one embodiment, when the drive circuit 202 is in the deactivated mode, the detection signal generation circuit 204 may be configured to generate a detection signal based on the live line output signals L1_OUT, L2_OUT, L3_OUT and the neutral line output signal N_OUT to indicate whether there is a first fault in the AC system.

[0047] In one embodiment, when the drive circuit 202 is in the active mode, the detection signal generation circuit 204 may be configured to generate a detection signal based on the drive signal to indicate whether there is a second fault in the AC system.

[0048] In one embodiment, the detection circuit 200 may further include a control circuit (not shown). For example, in some cases, the control circuit may be configured to deactivate the drive circuit 202 and indicate whether there is a first fault in the AC system based on the detection signal. For another example, in some cases, the control circuit may be configured to activate the drive circuit 202 and indicate whether there is a second fault in the AC system based on the detection signal. In one embodiment, the control circuit may include a microcontroller and its peripheral circuits.

[0049] Figure 3 A block diagram of a detection circuit 300 for a three-phase AC system according to another embodiment of the present invention is shown. For example, the detection circuit 300 may be Figure 2 the detection circuit 200 in. The detection circuit 300 may include a drive circuit 302 and a detection signal generation circuit 304. For example, the drive circuit 302 may be Figure 2 the drive circuit 202 in, and the detection signal generation circuit 304 may be Figure 2 the detection signal generation circuit 204 in. The drive circuit 302 may include a drive signal generation circuit 306 and a first isolation circuit 308.

[0050] The drive signal generation circuit 306 may be configured to receive an enable signal and generate a drive signal based on the enable signal.

[0051] The first isolation circuit 308 may include a plurality of isolation switches. One ends of the plurality of isolation switches may be electrically coupled to the output terminal of the drive signal generation circuit 306 respectively, and the detection signal generation circuit 304 may be electrically coupled to the other ends of the plurality of isolation switches via a plurality of live wire signal input terminals respectively.

[0052] By using the first isolation circuit, isolation between the strong and weak electricity is achieved, and the safety and reliability of the system are improved with a relatively low increase in cost.

[0053] In one embodiment, the detection circuit 300 may further include a control circuit (not shown). For example, in some cases, the control circuit may be configured to turn off all of the plurality of isolation switches to deactivate the drive circuit 302. Also for example, in some cases, the control circuit may be configured to provide an enable signal to the drive signal generation circuit 306 and close a selected isolation switch among the plurality of isolation switches to activate the drive circuit 302. In one embodiment, the selected isolation switch may be any one of the plurality of isolation switches. In one embodiment, the control circuit may include a microcontroller and its peripheral circuits.

[0054] In one embodiment, the control circuit may be configured to: deactivate the drive circuit 302; determine whether the level of each of the detection signals is a first level; if it is determined that the level of each of the detection signals is the first level, indicate that there is no first fault in the AC system; if it is determined that the level of at least one of the detection signals is a second level, indicate that there is a first fault in the AC system. For example, the first level may be a high level, and the second level may be a low level. It should be understood that when using different circuit structures, the first level and the second level may also be a low level and a high level, respectively.

[0055] In one embodiment, the control circuit may be configured to: activate the drive circuit 302; determine whether the level of the selected detection signal corresponding to the selected isolation switch among the detection signals is a second level and the levels of the remaining detection signals are a first level; if it is determined that the level of the selected detection signal is a second level and the levels of the remaining detection signals among the detection signals are a first level, indicate that there is no second fault at the output terminal of the live wire relay corresponding to the selected detection signal.

[0056] In one embodiment, the control circuit may be further configured to: if it is determined that the level of the selected detection signal is a first level, or if it is determined that the level of the selected detection signal is a second level and the level of any one of the remaining detection signals among the detection signals is a second level, indicate that there is a second fault in the AC system.

[0057] In one embodiment, the control circuit may be further configured to: if it is determined that the level of the selected detection signal is a first level, indicate that there is a live-to-ground short circuit at the output terminal of the live wire relay corresponding to the selected detection signal; if it is determined that the level of the selected detection signal is a second level and the level of any one of the remaining detection signals among the detection signals is a second level, indicate that there is a phase-to-phase short circuit between the output terminal of the live wire relay corresponding to the selected detection signal and the relay corresponding to the remaining detection signal having the second level.

[0058] Figure 4Fig. 0 shows a schematic connection diagram of a detection circuit 400 for a three-phase AC system according to an embodiment of the present invention. For example, the detection circuit 400 can be the detection circuit 300 in Figure 3 As shown in the figure, the detection circuit 400 includes a driving circuit and a detection signal generation circuit. The driving circuit includes a driving signal generation circuit and a first isolation circuit.

[0059] The driving signal generation circuit includes resistors R1, R2, R3, MOS transistor Q1, bipolar transistor Q2, and diode D1. One end of resistor R1 is electrically coupled to the source of MOS transistor Q1, and the other end is electrically coupled to the gate of MOS transistor Q1. One end of resistor R2 is electrically coupled to the gate of MOS transistor Q1, and the other end is electrically coupled to the collector of bipolar transistor Q2. The drain of MOS transistor Q1 is electrically coupled to the anode of diode D1. One end of resistor R3 is electrically coupled to the cathode of diode D1, and the other end is electrically coupled to ground. The driving signal generation circuit receives an enable signal PWM from the base of bipolar transistor Q2 and generates a driving signal VCC_PWM at the cathode of diode D1 based on the PWM signal.

[0060] The first isolation circuit includes a plurality of isolation switches K1, K2, K3. One ends of the plurality of isolation switches K1, K2, K3 can be electrically coupled to the output terminal of the driving signal generation circuit respectively, and the detection signal generation circuit is electrically coupled to the other ends of the plurality of isolation switches K1, K2, K3 via a plurality of live wire signal input terminals respectively.

[0061] The detection signal generation circuit includes a first circuit, a second circuit, a third circuit, and a fourth circuit.

[0062] The first circuit includes capacitors C1, C5, resistors R4, R5, R12, and optocoupler U1. In the first circuit, one end of capacitor C1 is electrically coupled to the output terminal of the first live wire relay among a plurality of live wire relays and is electrically coupled to isolation switch K1, and the other end is sequentially connected to R4, the primary side of U1, R5 and then electrically coupled to ground. One end of resistor R12 is electrically coupled to the DC voltage 3.3V, and the other end is electrically coupled to the collector of the transistor on the secondary side of U1. A capacitor C5 is connected in parallel between the collector and the emitter of the transistor on the secondary side of U1. The emitter of the transistor on the secondary side of U1 is electrically coupled to GND. The first circuit outputs a first live wire detection signal V_IN1 at the collector of the transistor on the secondary side of U1.

[0063] The second circuit includes capacitors C2, C6, resistors R6, R7, R13, and optocoupler U2. In the second circuit, one end of capacitor C2 is electrically coupled to the output terminal of the second live wire relay among the multiple live wire relays, and is also electrically coupled to disconnect switch K2. The other end is sequentially connected to R6, the primary side of U2, R7, and then electrically coupled to ground. One end of resistor R13 is electrically coupled to the DC voltage 3.3V, and the other end is electrically coupled to the collector of the triode on the secondary side of U2. A capacitor C6 is connected in parallel between the collector and the emitter of the triode on the secondary side of U2. The emitter of the triode on the secondary side of U2 is electrically coupled to GND. The second circuit outputs a second live wire detection signal V_IN2 at the collector of the triode on the secondary side of U2.

[0064] The third circuit includes capacitors C3, C7, resistors R8, R9, R14, and optocoupler U3. In the third circuit, one end of capacitor C3 is electrically coupled to the output terminal of the third live wire relay among the multiple live wire relays, and is also electrically coupled to disconnect switch K3. The other end is sequentially connected to R8, the primary side of U3, R9, and then electrically coupled to ground. One end of resistor R14 is electrically coupled to the DC voltage 3.3V, and the other end is electrically coupled to the collector of the triode on the secondary side of U3. A capacitor C7 is connected in parallel between the collector and the emitter of the triode on the secondary side of U3. The emitter of the triode on the secondary side of U3 is electrically coupled to GND. The third circuit outputs a third live wire detection signal V_IN3 at the collector of the triode on the secondary side of U3.

[0065] The fourth circuit includes capacitors C4, C8, resistors R10, R11, R15, and optocoupler U4. In the fourth circuit, one end of capacitor C4 is electrically coupled to the output terminal of the neutral wire relay. The other end is sequentially connected to R10, the primary side of U4, R11, and then electrically coupled to ground. One end of resistor R15 is electrically coupled to the DC voltage 3.3V, and the other end is electrically coupled to the collector of the triode on the secondary side of U4. A capacitor C8 is connected in parallel between the collector and the emitter of the triode on the secondary side of U4. The emitter of the triode on the secondary side of U4 is electrically coupled to GND. The fourth circuit outputs a neutral wire detection signal V_IN4 at the collector of the triode on the secondary side of U4.

[0066] In one embodiment, capacitors C1, C2, C3, and C4 can all be high-voltage ceramic capacitors for withstanding high voltages.

[0067] In one embodiment, the detection circuit 400 may further include a control circuit (not shown). For example, in some cases, the control circuit may be configured to disconnect all of the plurality of isolation switches K1, K2, and K3 to deactivate the drive circuit. For another example, in some cases, the control circuit may be configured to provide an enable signal to the drive signal generation circuit and close a selected one of the plurality of isolation switches K1, K2, and K3 to activate the drive circuit. In one embodiment, the selected isolation switch may be any one of the plurality of isolation switches K1, K2, and K3. In one embodiment, the control circuit may include a microcontroller and its peripheral circuits.

[0068] In one embodiment, the control circuit may be configured to: deactivate the drive circuit; determine whether the level of each of the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is a first level; if it is determined that the level of each of the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is the first level, indicate that there is no first fault in the AC system; if it is determined that the level of at least one of the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is a second level, indicate that there is a first fault in the AC system. For example, the first level may be a high level, and the second level may be a low level. It should be understood that in the case of using different circuit structures, the first level and the second level may also be a low level and a high level, respectively.

[0069] In one embodiment, the control circuit may be configured to: activate the drive circuit; determine whether the level of the selected detection signal corresponding to the selected isolation switch among the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is a second level and the levels of the remaining detection signals are a first level; if it is determined that the level of the selected detection signal is a second level and the levels of the remaining detection signals among the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 are a first level, indicate that there is no second fault at the output end of the line relay corresponding to the selected detection signal.

[0070] In one embodiment, the control circuit may further be configured to: if it is determined that the level of the selected detection signal is a first level, or if it is determined that the level of the selected detection signal is a second level and the level of any one of the remaining detection signals among the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is a second level, indicate that there is a second fault in the AC system.

[0071] In one embodiment, the control circuit may further be configured to: if it is determined that the level of the selected detection signal is a first level, indicate that there is a line-to-ground short circuit at the output terminal of the live wire relay corresponding to the selected detection signal; if it is determined that the level of the selected detection signal is a second level and the level of any one of the remaining detection signals among the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is a second level, indicate that there is a phase-to-phase short circuit between the output terminal of the live wire relay corresponding to the selected detection signal and the relay corresponding to the remaining detection signal having the second level.

[0072] Figure 5A FIG. 500 shows a flowchart of operations 500 performed by a control circuit according to an embodiment of the present invention.

[0073] At step 502, the drive circuit is placed in a deactivated mode.

[0074] At step 504, it is determined whether the level of each of the detection signals is a first level.

[0075] If it is determined at step 504 that the level of each of the detection signals is a first level, then at step 506 it is indicated that there is no first fault in the three-phase AC system.

[0076] If it is determined at step 504 that the level of at least one of the detection signals is a second level, then at step 508 it is indicated that there is a first fault in the three-phase AC system.

[0077] For example, in some cases, with reference to Figure 4, the control circuit can be configured to: completely disconnect multiple isolation switches K1, K2, and K3 to deactivate the drive circuit. Then, it is determined whether the level of each of the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is the first level (e.g., high level). If the levels of each of the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 are all the first level, it indicates that there is no first fault in the three-phase AC system. If the first live wire detection signal V_IN1 is the second level (e.g., low level), it indicates that there is a first fault in the three-phase AC system, for example, the first live wire relay corresponding to V_IN1 has a sticking fault. If the second live wire detection signal V_IN2 is the second level (e.g., low level), it indicates that there is a first fault in the three-phase AC system, for example, the second live wire relay corresponding to V_IN2 has a sticking fault. If the third live wire detection signal V_IN3 is the second level (e.g., low level), it indicates that there is a first fault in the three-phase AC system, for example, the third live wire relay corresponding to V_IN3 has a sticking fault. If the neutral wire detection signal V_IN4 is the second level (e.g., low level), it indicates that there is a first fault in the three-phase AC system, for example, the neutral wire relay corresponding to V_IN4 has a sticking fault.

[0078] Figure 5B The flowchart of operation 510 performed by the control circuit according to another embodiment of the present invention is shown.

[0079] At step 512, the drive circuit is placed in the active mode.

[0080] At step 514, it is determined whether the level of the selected detection signal corresponding to the selected isolation switch among the detection signals is the second level and the levels of the remaining detection signals are the first level.

[0081] If it is determined at step 514 that the level of the selected detection signal is the second level and the levels of the remaining detection signals among the detection signals are the first level, then at step 516, it is indicated that there is no second fault in the three-phase AC system.

[0082] If it is determined at step 514 that the level of the selected detection signal is the first level, or if it is determined that the level of the selected detection signal is the second level and the level of any one of the remaining detection signals among the detection signals is the second level, then at step 518, it is indicated that there is a second fault in the three-phase AC system.

[0083] For example, in some cases, referring to Figure 4, the control circuit can be configured to: provide an enable signal to the base of the triode Q2 of the drive signal generation circuit in the drive circuit, and close K1 among the plurality of isolation switches K1, K2, and K3, so that the drive circuit is in an active mode. Then, judge the levels of the first live wire detection signal V_IN1 corresponding to the isolation switch K1 and the levels of the remaining detection signals V_IN2, V_IN3, and V_IN4 in the detection signal. If it is determined that the level of the first live wire detection signal V_IN1 is the second level and the levels of V_IN2, V_IN3, and V_IN4 are all the first level, it indicates that there is no second fault in the three-phase AC system. If it is determined that the level of the first live wire detection signal V_IN1 is the first level, it indicates that there is a second fault in the three-phase AC system. For example, there is a live wire to ground short circuit fault at the output end of the first live wire relay. If it is determined that the level of the first live wire detection signal V_IN1 is the second level and the level of any one of V_IN2, V_IN3, and V_IN4 is the second level, it indicates that there is a second fault in the three-phase AC system. For example, if it is determined that the level of the first live wire detection signal V_IN1 is the second level and the level of V_IN2 is the second level, there is a phase-to-phase short circuit fault between the output end of the first live wire relay and the output end of the second live wire relay. For example, if it is determined that the level of the first live wire detection signal V_IN1 is the second level and the level of V_IN3 is the second level, there is a phase-to-phase short circuit fault between the output end of the first live wire relay and the output end of the third live wire relay. For example, if it is determined that the level of the first live wire detection signal V_IN1 is the second level and the level of V_IN4 is the second level, there is a phase-to-phase short circuit (live wire to neutral short circuit) fault between the output end of the first live wire relay and the output end of the neutral wire relay.

[0084] For example, in some cases, referring to Figure 4, the control circuit can be configured to: provide an enabling signal to the base of the triode Q2 of the drive signal generation circuit in the drive circuit, and close K2 among the plurality of isolation switches K1, K2, and K3, so that the drive circuit is in an active mode. Then, judge the levels of the second live wire detection signal V_IN2 corresponding to the isolation switch K2 and the levels of the remaining detection signals V_IN1, V_IN3, and V_IN4 in the detection signal. If it is determined that the second live wire detection signal V_IN2 is at the second level and the levels of V_IN1, V_IN3, and V_IN4 are all at the first level, it indicates that there is no second fault in the three-phase AC system. If it is determined that the level of the second live wire detection signal V_IN2 is at the first level, it indicates that there is a second fault in the three-phase AC system. For example, there is a live-ground short circuit fault at the output end of the second live wire relay. If it is determined that the level of the second live wire detection signal V_IN2 is at the second level and the level of any one of V_IN1, V_IN3, and V_IN4 is at the second level, it indicates that there is a second fault in the three-phase AC system. For example, if it is determined that the level of the second live wire detection signal V_IN2 is at the second level and the level of V_IN1 is at the second level, there is a phase-to-phase short circuit fault between the output end of the second live wire relay and the output end of the first live wire relay. For example, if it is determined that the level of the second live wire detection signal V_IN2 is at the second level and the level of V_IN3 is at the second level, there is a phase-to-phase short circuit fault between the output end of the second live wire relay and the output end of the third live wire relay. For example, if it is determined that the level of the second live wire detection signal V_IN2 is at the second level and the level of V_IN4 is at the second level, there is a phase-to-phase short circuit (live-neutral short circuit) fault between the output end of the second live wire relay and the output end of the neutral wire relay.

[0085] For example, in some cases, referring to Figure 4, the control circuit can be configured to: provide an enable signal to the base of the triode Q2 of the drive signal generation circuit in the drive circuit, and close K3 among the plurality of isolation switches K1, K2, K3, so that the drive circuit is in an active mode. Then, it determines the level of the third live wire detection signal V_IN3 corresponding to the isolation switch K3 and the levels of the remaining detection signals V_IN1, V_IN2, and V_IN4 in the detection signal. If it is determined that the level of the third live wire detection signal V_IN3 is the second level and the levels of V_IN1, V_IN2, and V_IN4 are all the first level, it indicates that there is no second fault in the three-phase AC system. If it is determined that the level of the third live wire detection signal V_IN3 is the first level, it indicates that there is a second fault in the three-phase AC system. For example, there is a live-to-ground short circuit fault at the output end of the third live wire relay. If it is determined that the level of the third live wire detection signal V_IN3 is the second level and the level of any one of V_IN1, V_IN2, and V_IN4 is the second level, it indicates that there is a second fault in the three-phase AC system. For example, if it is determined that the level of the third live wire detection signal V_IN3 is the second level and the level of V_IN1 is the second level, there is a phase-to-phase short circuit fault between the output end of the third live wire relay and the output end of the first live wire relay. For example, if it is determined that the level of the third live wire detection signal V_IN3 is the second level and the level of V_IN2 is the second level, there is a phase-to-phase short circuit fault between the output end of the third live wire relay and the output end of the second live wire relay. For example, if it is determined that the level of the third live wire detection signal V_IN3 is the second level and the level of V_IN4 is the second level, there is a phase-to-phase short circuit (live-to-neutral short circuit) fault between the output end of the third live wire relay and the output end of the neutral wire relay.

[0086] Figure 6 FIG. shows a block diagram of a detection circuit 600 for a three-phase AC system according to another embodiment of the present invention. For example, the detection circuit 600 can be Figure 2 the detection circuit 200 in Figure 2 The detection circuit 600 can include a drive circuit 602 and a detection signal generation circuit 604. For example, the drive circuit 602 can be Figure 2 the drive circuit 202 in

[0087] and the detection signal generation circuit 604 can be

[0088] The second isolation circuit 608 may include a plurality of isolation capacitors. One ends of the plurality of isolation capacitors are electrically coupled to the plurality of drive signal generation circuits 606_1, 606_2, 606_3 respectively, and the detection signal generation circuit 604 is electrically coupled to the other ends of the plurality of isolation capacitors via the plurality of live wire signal input terminals.

[0089] By utilizing the second isolation circuit, isolation between the strong and weak electricity is achieved, and the safety and reliability of the system are improved with a relatively low increase in cost.

[0090] In one embodiment, the detection circuit 600 may further include an isolated power supply module (not shown). The isolated power supply module may be configured to isolate the power supply signal to generate an isolated power supply signal. The plurality of drive signal generation circuits 606_1, 606_2, 606_3 may be configured to be powered by the isolated power supply signal. For example, if the power supply signal is a DC voltage of 12V, the isolated power supply module may isolate it to generate an isolated power supply signal with a DC voltage of 12V. Another example, if the power supply signal is a DC voltage of 24V, the isolated power supply module may isolate it to generate an isolated power supply signal with a DC voltage of 24V.

[0091] In one embodiment, the detection circuit 600 may further include a control circuit (not shown). For example, in some cases, the control circuit may be configured to cause the output signals of the plurality of drive signal generation circuits 606_1, 606_2, 606_3 to be isolated by the second isolation circuit 608, so that the drive circuit 602 is in a deactivated mode. As an example, no signal may be provided to any one of the plurality of drive signal generation circuits 606_1, 606_2, 606_3. As another example, the signal provided to any one of the plurality of drive signal generation circuits 606_1, 606_2, 606_3 may be made unable to flow through the second isolation circuit. For example, the provided signal is a low-frequency signal. Another example, in some cases, the control circuit may be configured to provide an enable signal to a selected drive signal generation circuit among the plurality of drive signal generation circuits 606_1, 606_2, 606_3, so that the drive circuit 602 is in an activated mode. In one embodiment, the selected drive signal generation circuit may be any one of the plurality of drive signal generation circuits 606_1, 606_2, 606_3. In one embodiment, the control circuit may include a microcontroller and its peripheral circuits.

[0092] In one embodiment, the control circuit may be configured to: deactivate the drive circuit 602; determine whether the level of each of the detection signals is a first level; if it is determined that the level of each of the detection signals is the first level, indicate that there is no first fault in the AC system; if it is determined that the level of at least one of the detection signals is a second level, indicate that there is a first fault in the AC system. For example, the first level may be a high level, and the second level may be a low level. It should be understood that when different circuit structures are used, the first level and the second level may also be a low level and a high level, respectively.

[0093] In one embodiment, the control circuit may be configured to: activate the drive circuit 602; determine whether the level of the selected detection signal corresponding to the selected drive signal generation circuit in the detection signals is a second level and the levels of the remaining detection signals are a first level; if it is determined that the level of the selected detection signal is a second level and the levels of the remaining detection signals in the detection signals are a first level, indicate that there is no second fault at the output end of the live wire relay corresponding to the selected detection signal.

[0094] In one embodiment, the control circuit may be further configured to: if it is determined that the level of the selected detection signal is a first level, or if it is determined that the level of the selected detection signal is a second level and the level of any one of the remaining detection signals in the detection signals is a second level, indicate that there is a second fault in the AC system.

[0095] In one embodiment, the control circuit may be further configured to: if it is determined that the level of the selected detection signal is a first level, indicate that there is a live-to-ground short circuit at the output end of the live wire relay corresponding to the selected detection signal; if it is determined that the level of the selected detection signal is a second level and the level of any one of the remaining detection signals in the detection signals is a second level, indicate that there is a phase-to-phase short circuit between the output end of the live wire relay corresponding to the selected detection signal and the relay corresponding to the remaining detection signal having the second level.

[0096] Figure 7 FIG. shows a schematic connection diagram of a detection circuit 700 for a three-phase AC system according to another embodiment of the present invention. For example, the detection circuit 700 may be the detection circuit 600 in Figure 6 As shown in the figure, the detection circuit 600 includes a drive circuit and a detection signal generation circuit. The drive circuit includes a plurality of drive signal generation circuits and a second isolation circuit.

[0097] One of the multiple drive signal generation circuits includes resistors R1, R2, R3, R4, optocoupler U1, MOS transistor Q1, and diode D1. VCC is electrically coupled to the source of MOS transistor Q1, and the drain of MOS transistor Q1 is electrically coupled to the anode of diode D1. The cathode of diode D1 is electrically coupled to resistor R4. Resistors R1, R2, R3, and U1 form the drive circuit of MOS transistor Q1. Resistor R1 is electrically coupled across the gate-source of MOS transistor Q1. One end of resistor R2 is electrically coupled to the gate of MOS transistor Q1, and the other end is electrically coupled to the collector of the secondary transistor of optocoupler U1. The emitter of the secondary transistor of optocoupler U1 is electrically coupled to ground. One end of resistor R3 is electrically coupled to one end of the primary side of optocoupler U1, and the other end is used to receive the enable signal PWM_1. The other end of the primary side of optocoupler U1 is electrically coupled to ground. The drive signal VCC_PWM_1 is output at the cathode of diode D1.

[0098] Another one of the multiple drive signal generation circuits includes resistors R5, R6, R7, R8, optocoupler U2, MOS transistor Q2, and diode D2. VCC is electrically coupled to the source of MOS transistor Q2, and the drain of MOS transistor Q2 is electrically coupled to the anode of diode D2. The cathode of diode D2 is electrically coupled to resistor R8. Resistors R5, R6, R7, and U2 form the drive circuit of MOS transistor Q2. Resistor R5 is electrically coupled across the gate-source of MOS transistor Q2. One end of resistor R6 is electrically coupled to the gate of MOS transistor Q2, and the other end is electrically coupled to the collector of the secondary transistor of optocoupler U2. The emitter of the secondary transistor of optocoupler U2 is electrically coupled to ground. One end of resistor R7 is electrically coupled to one end of the primary side of optocoupler U2, and the other end is used to receive the enable signal PWM_2. The other end of the primary side of optocoupler U2 is electrically coupled to ground. The drive signal VCC_PWM_2 is output at the cathode of diode D2.

[0099] Another one of the multiple drive signal generation circuits includes resistors R9, R10, R11, R12, optocoupler U3, MOS transistor Q3, and diode D3. VCC is electrically coupled to the source of MOS transistor Q3, and the drain of MOS transistor Q3 is electrically coupled to the anode of diode D3. The cathode of diode D3 is electrically coupled to resistor R12. Resistors R9, R10, R11, and U3 form the drive circuit of MOS transistor Q3. Resistor R9 is electrically coupled across the gate-source of MOS transistor Q3. One end of resistor R10 is electrically coupled to the gate of MOS transistor Q3, and the other end is electrically coupled to the collector of the secondary transistor of optocoupler U3. The emitter of the secondary transistor of optocoupler U3 is electrically coupled to ground. One end of resistor R11 is electrically coupled to one end of the primary side of optocoupler U3, and the other end is used to receive the enable signal PWM_3. The other end of the primary side of optocoupler U3 is electrically coupled to ground. The drive signal VCC_PWM_3 is output at the cathode of diode D3.

[0100] The second isolation circuit includes a plurality of isolation capacitors C5, C6, and C7. One ends of the plurality of isolation capacitors C5, C6, and C7 are respectively electrically coupled to the output ends of the plurality of driving signal generation circuits, and the detection signal generation circuit is electrically coupled to the other ends of the plurality of isolation capacitors C5, C6, and C7 via the plurality of live wire signal input ends.

[0101] Since the topology of the detection signal generation circuit has been described above in conjunction with Figure 4 it will not be repeated here to avoid redundancy.

[0102] Regarding the coupling manner of the detection signal generation circuit and Figure 7 the driving circuit described in is set as follows: One end of capacitor C1 is electrically coupled to the output end of the first live wire relay among the plurality of live wire relays and is electrically coupled to isolation capacitor C5, and the other end is sequentially connected to R13 and the primary side of U4 and then electrically coupled to ground, where R14 is connected across both ends of the primary side of U4. One end of capacitor C2 is electrically coupled to the output end of the second live wire relay among the plurality of live wire relays and is electrically coupled to isolation capacitor C6, and the other end is sequentially connected to R16, the primary side of U5 and electrically coupled to ground, where R17 is connected across both ends of the primary side of U5. One end of capacitor C3 is electrically coupled to the output end of the third live wire relay among the plurality of live wire relays and is electrically coupled to isolation capacitor C7, and the other end is sequentially connected to R19, the primary side of U6 and electrically coupled to ground, where R20 is connected across both ends of the primary side of U6.

[0103] In one embodiment, capacitors C1, C2, C3, C4, and capacitors C5, C6, C7 in the detection signal generation circuit can all be high-voltage ceramic capacitors for withstanding high voltage.

[0104] In one embodiment, the detection circuit 700 may further include a control circuit (not shown). For example, in some cases, the control circuit may be configured to isolate the output signals of the plurality of driving signal generation circuits by the second isolation circuit so that the driving circuit is in a deactivated mode. As an example, no signal may be provided to any one of the plurality of driving signal generation circuits. As another example, the signal provided to any one of the plurality of driving signal generation circuits may be made unable to flow through the second isolation circuit. For example, the provided signal is a low-frequency signal. Also for example, in some cases, the control circuit may be configured to provide an enable signal to a selected driving signal generation circuit of the plurality of driving signal generation circuits so that the driving circuit is in an activated mode. In one embodiment, the selected driving signal generation circuit may be any one of the plurality of driving signal generation circuits. In one embodiment, the control circuit may include a microcontroller and its peripheral circuits.

[0105] In one embodiment, the control circuit may be configured to: deactivate the drive circuit; determine whether the levels of each of the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 are all a first level; if it is determined that the levels of each of the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 are all the first level, indicate that there is no first fault in the AC system; if it is determined that the level of at least one of the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is a second level, indicate that there is a first fault in the AC system. For example, the first level may be a high level, and the second level may be a low level. It should be understood that in the case of using different circuit structures, the first level and the second level may also be a low level and a high level, respectively.

[0106] In one embodiment, the control circuit may be configured to: activate the drive circuit; determine whether the level of the selected detection signal corresponding to the selected drive signal generation circuit among the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is a second level and the levels of the remaining detection signals are a first level; if it is determined that the level of the selected detection signal is a second level and the levels of the remaining detection signals among the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 are a first level, indicate that there is no second fault at the output terminal of the line relay corresponding to the selected detection signal.

[0107] In one embodiment, the control circuit may be further configured to: if it is determined that the level of the selected detection signal is a first level, or if it is determined that the level of the selected detection signal is a second level and the level of any one of the remaining detection signals among the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is a second level, indicate that there is a second fault in the AC system.

[0108] In one embodiment, the control circuit may be further configured to: if it is determined that the level of the selected detection signal is a first level, indicate that there is a line-to-ground short circuit at the output terminal of the line relay corresponding to the selected detection signal; if it is determined that the level of the selected detection signal is a second level and the level of any one of the remaining detection signals among the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is a second level, indicate that there is a phase-to-phase short circuit between the output terminal of the line relay corresponding to the selected detection signal and the relay corresponding to the remaining detection signal having the second level.

[0109] Figure 8 FIG. shows a schematic connection diagram of a detection circuit 800 for a three-phase AC system according to still another embodiment of the present invention. For example, the detection circuit 800 may be Figure 7The detection circuit 700 therein. The detection circuit 800 may further include an isolated power supply module U8. The isolated power supply module U8 may be configured to isolate the power supply signal VCC to generate an isolated power supply signal ISO_VCC.

[0110] As shown in the figure, the isolated power supply module U8 is electrically coupled to the capacitor C13 at its input side and is electrically coupled to the capacitor C14 at its output terminal. One end of the capacitor C13 is used to receive the power supply signal VCC, and the other end is electrically coupled to the digital ground. One end of the capacitor C14 is used to output the isolated power supply signal ISO_VCC, and the other end is electrically coupled to the power ground. The digital ground is electrically coupled to the power ground through the capacitor C12, and the digital ground is electrically coupled to the ground PE through the bead L1.

[0111] By using a combination of capacitors and beads, the electromagnetic compatibility of the circuit can be significantly improved, the interference of the circuit to external devices can be reduced, and at the same time, its own anti-interference ability can be improved. By appropriately selecting the parameters of the capacitors and beads, a good grounding effect can be achieved while maintaining the stability and reliability of the circuit operation.

[0112] A plurality of drive signal generation circuits 606_1, 606_2, 606_3 are configured to be powered by the isolated power supply signal ISO_VCC and respectively output drive signals ISO_PWM_1, ISO_PWM_2, and ISO_PWM_3. For example, if the power supply signal VCC is a DC voltage of 12V, the isolated power supply module U8 can isolate it to generate an isolated power supply signal ISO_VCC with a DC voltage of 12V. Another example is that if the power supply signal VCC is a DC voltage of 24V, the isolated power supply module U8 can isolate it to generate an isolated power supply signal ISO_VCC with a DC voltage of 24V.

[0113] By using the isolated power supply module to supply power to a plurality of drive signal generation circuits, relevant electrical safety standards can be met, isolation between strong and weak electricity can be achieved, the circuit can be protected from surge voltage and transient high voltage impacts, and the safety and robustness of the circuit can be improved.

[0114] Other devices of the detection circuit 800 are similar to those of the detection circuit 700. To avoid ambiguity, the description of similar devices is omitted here.

[0115] Since the operation steps of the detection circuit have been described above in conjunction with Figure 7 For the sake of avoiding redundancy, they will not be elaborated here.

[0116] It should be understood that when using Figure 8When the detection circuit in it detects a line-to-ground short circuit in the AC system, the capacitor C12 is electrically coupled between the output of the line relay and both ends of the power ground. Therefore, the voltage across the capacitor C12 depends on the input of the drive signal and the voltage division with the capacitors C5, C6, and C7 in the second isolation circuit. By appropriately adjusting the values of the capacitors C5, C6, and C7 and the values of the resistors R13, R14, R16, R17, R19, R20, R22, and R23, it can be ensured that the primary side voltages of the optocouplers U4, U5, U6, and U7 are always lower than the startup threshold when a line-to-ground short circuit occurs, ensuring that the optocouplers are not turned on in this case, thereby realizing the detection of the line-to-ground short circuit.

[0117] Figure 9A FIG. shows a flowchart of operation 900 performed by a control circuit according to another embodiment of the present invention.

[0118] At step 902, the drive circuit is placed in a deactivated mode.

[0119] At step 904, it is determined whether the level of each of the detection signals is the first level.

[0120] If it is determined at step 904 that the level of each of the detection signals is the first level, then at step 906 it is indicated that there is no first fault in the three-phase AC system.

[0121] If it is determined at step 904 that the level of at least one of the detection signals is the second level, then at step 908 it is indicated that there is a first fault in the three-phase AC system.

[0122] For example, in some cases, with reference to Figure 7 or Figure 8, the control circuit can be configured to: isolate the output signals of multiple drive signal generation circuits in the drive circuit by a second isolation circuit, so that the drive circuit is in a deactivated mode. Then, it is determined whether the level of each of the detection signals V_IN1, V_IN2, V_IN3, and V_IN4 is a first level (e.g., high level). If the levels of V_IN1, V_IN2, V_IN3, and V_IN4 are all the first level, it indicates that there is no first fault in the three-phase AC system. If V_IN1 is a second level (e.g., low level), it indicates that there is a first fault in the three-phase AC system, for example, the first live wire relay corresponding to V_IN1 has a sticking fault. If V_IN2 is a second level (e.g., low level), it indicates that there is a first fault in the three-phase AC system, for example, the second live wire relay corresponding to V_IN2 has a sticking fault. If V_IN3 is a second level (e.g., low level), it indicates that there is a first fault in the three-phase AC system, for example, the third live wire relay corresponding to V_IN3 has a sticking fault. If V_IN4 is a second level (e.g., low level), it indicates that there is a first fault in the three-phase AC system, for example, the neutral wire relay corresponding to V_IN4 has a sticking fault.

[0123] Figure 9B FIG. shows a flowchart of operation 910 performed by a control circuit according to another embodiment of the present invention.

[0124] At step 912, the drive circuit is placed in an active mode.

[0125] At step 914, it is determined whether the level of the selected detection signal corresponding to the selected drive signal generation circuit among the detection signals is a second level and the levels of the remaining detection signals are a first level.

[0126] If it is determined at step 914 that the level of the selected detection signal is a second level and the levels of the remaining detection signals among the detection signals are a first level, then at step 916 it is indicated that there is no second fault in the three-phase AC system.

[0127] If it is determined at step 914 that the level of the selected detection signal is a first level, or if it is determined that the level of the selected detection signal is a second level and any one of the remaining detection signals among the detection signals is a second level, then at step 918 it is indicated that there is a second fault in the three-phase AC system.

[0128] For example, in some cases, referring to Figure 7 or Figure 8, the control circuit can be configured to: provide an enable signal to one end of a resistor R3 of a drive signal generation circuit in the drive circuit to enable the drive circuit to be in an active mode. Then, the levels of a first live wire detection signal V_IN1 corresponding to the drive signal generation circuit in the detection signal and the levels of the remaining detection signals V_IN2, V_IN3, and V_IN4 are determined. If it is determined that the level of the first live wire detection signal V_IN1 is a second level and the levels of V_IN2, V_IN3, and V_IN4 are all the first level, it indicates that there is no second fault in the three-phase AC system. If it is determined that the level of the first live wire detection signal V_IN1 is the first level, it indicates that there is a second fault in the three-phase AC system. For example, there is a live wire to ground short circuit fault at the output end of the first live wire relay. If it is determined that the level of the first live wire detection signal V_IN1 is the second level and the level of any one of V_IN2, V_IN3, and V_IN4 is the second level, it indicates that there is a second fault in the three-phase AC system. For example, if it is determined that the level of the first live wire detection signal V_IN1 is the second level and the level of V_IN2 is the second level, there is a phase-to-phase short circuit fault between the output end of the first live wire relay and the output end of the second live wire relay. For example, if it is determined that the level of the first live wire detection signal V_IN1 is the second level and the level of V_IN3 is the second level, there is a phase-to-phase short circuit fault between the output end of the first live wire relay and the output end of the third live wire relay. For example, if it is determined that the level of the first live wire detection signal V_IN1 is the second level and the level of V_IN4 is the second level, there is a phase-to-phase short circuit (live wire to neutral short circuit) fault between the output end of the first live wire relay and the output end of the neutral wire relay.

[0129] For example, in some cases, referring to Figure 7 or Figure 8, the control circuit can be configured to: provide an enable signal to one end of a resistor R7 of another drive signal generation circuit in the drive circuit to make the drive circuit in an active mode. Then, judge the levels of a second live wire detection signal V_IN2 corresponding to the drive signal generation circuit in the detection signal and the levels of the remaining detection signals V_IN1, V_IN3 and V_IN4. If it is determined that the level of the second live wire detection signal V_IN2 is a second level and the levels of V_IN1, V_IN3 and V_IN4 are all a first level, it indicates that there is no second fault in the three-phase AC system. If it is determined that the level of the second live wire detection signal V_IN2 is a first level, it indicates that there is a second fault in the three-phase AC system. For example, there is a live wire to ground short circuit fault at the output end of the second live wire relay. If it is determined that the level of the second live wire detection signal V_IN2 is a second level and the level of any one of V_IN1, V_IN3 and V_IN4 is a second level, it indicates that there is a second fault in the three-phase AC system. For example, if it is determined that the level of the second live wire detection signal V_IN2 is a second level and the level of V_IN1 is a second level, there is a phase-to-phase short circuit fault between the output end of the second live wire relay and the output end of the first live wire relay. For example, if it is determined that the level of the second live wire detection signal V_IN2 is a second level and the level of V_IN3 is a second level, there is a phase-to-phase short circuit fault between the output end of the second live wire relay and the output end of the third live wire relay. For example, if it is determined that the level of the second live wire detection signal V_IN2 is a second level and the level of V_IN4 is a second level, there is a phase-to-phase short circuit (live wire to neutral short circuit) fault between the output end of the second live wire relay and the output end of the neutral wire relay.

[0130] For example, in some cases, refer to Figure 7 or Figure 8, the control circuit can be configured to: provide an enable signal to one end of a resistor R11 of another drive signal generation circuit in the drive circuit to make the drive circuit in an active mode. Then, it determines the level of a third line detection signal V_IN3 corresponding to this drive signal generation circuit in the detection signal and the levels of the remaining detection signals V_IN1, V_IN2, and V_IN4. If it is determined that the level of the third line detection signal V_IN3 is a second level and the levels of V_IN1, V_IN2, and V_IN4 are all the first level, it indicates that there is no second fault in the three-phase AC system. If it is determined that the level of the third line detection signal V_IN3 is the first level, it indicates that there is a second fault in the three-phase AC system. For example, there is a line-to-ground short circuit fault at the output end of the third line relay. If it is determined that the level of the third line detection signal V_IN3 is the second level and the level of any one of V_IN1, V_IN2, and V_IN4 is the second level, it indicates that there is a second fault in the three-phase AC system. For example, if it is determined that the level of the third line detection signal V_IN3 is the second level and the level of V_IN1 is the second level, there is a phase-to-phase short circuit fault between the output end of the third line relay and the output end of the first line relay. For example, if it is determined that the level of the third line detection signal V_IN3 is the second level and the level of V_IN2 is the second level, there is a phase-to-phase short circuit fault between the output end of the third line relay and the output end of the second line relay. For example, if it is determined that the level of the third line detection signal V_IN3 is the second level and the level of V_IN4 is the second level, there is a phase-to-phase short circuit (line-to-neutral short circuit) fault between the output end of the third line relay and the output end of the neutral line relay.

[0131] Figure 10 The block diagram of a power supply device 1000 according to an embodiment of the present invention is shown. The power supply device 1000 may include: a plurality of line relays (a first line relay, a second line relay, a third line relay) and a neutral line relay provided on the lines and the neutral line in the three-phase AC system; and a detection circuit 1002. The detection circuit 1002 may be Figure 2 , Figure 3 , Figure 4 , Figure 6 , Figure 7 , Figure 8Any one of the detection circuits 200, 300, 400, 600, 700, 800 in the figure. The input ends of multiple live wire relays and neutral wire relays are used to receive L1_IN, L2_IN, L3_IN, and N_IN signals from the live wire and the neutral wire respectively. In a suitable scenario, the L1_OUT, L2_OUT, L3_OUT, and N_OUT signals at the output ends of multiple live wire relays and neutral wire relays are used to detect whether the live wire relays and / or neutral wire relays are stuck, and / or whether there are short circuit faults between the output ends of the live wire relays, between the output end of the live wire relay and the output end of the neutral wire relay, and between the output end of the live wire relay and the ground. For example, if any one of the above faults or any combination thereof exists, it indicates that there is a fault in the three-phase AC system, thereby deactivating the power supply device 1000. Another example is that if none of the above faults exist, the power supply device 1000 can be enabled to charge the device to be charged. In one embodiment, the device to be charged can be an electric vehicle. In one embodiment, the power supply device 1000 can be a charging pile.

[0132] By deactivating the power supply device 1000 in the event of the above faults, potential safety hazards during the charging process are avoided, ensuring the safety of the power supply device for power supply.

[0133] In one embodiment, when the device to be charged is disconnected from the power supply device 1000, the detection circuit can be configured to detect whether there is a fault in the three-phase AC system. For example, when the power supply device is installed, the detection circuit can be configured to detect whether there is a fault in the three-phase AC system. Another example is that before electrically coupling the device to be charged to the power supply device to start the charging process, the detection circuit can be configured to detect whether there is a fault in the three-phase AC system. Another example is that after electrolytically decoupling the device to be charged that has completed charging from the power supply device to stop the charging process, the detection circuit can be configured to detect whether there is a fault in the three-phase AC system.

[0134] In one embodiment, the detection circuit can be configured to periodically detect whether there is a fault in the three-phase AC system. The detection period and the number of detections can be set by the control circuit. For example, if the detection period is set to seven days and the number of detections is set to three times, then the three-phase AC system is detected three times every seven days for whether there is a fault.

[0135] In another embodiment, the detection circuit can be configured to perform detections as required, such as before and after charging.

[0136] By detecting whether there is a fault in the three-phase AC system as needed or in a suitable scenario, the activation or deactivation of the detection circuit can be actively controlled, reducing the system power consumption and extending the service life of the system. By setting the detection timing, detection period, detection times, etc. as needed, the flexibility of the system is greatly enhanced.

[0137] The above describes the detection circuit and power supply device for three-phase AC according to the exemplary embodiments of the present application. By adopting the above-described manner in which the detection signal generation circuit is electrically coupled to the output terminals of multiple live wire relays and neutral wire relays and the drive circuit, the detection signal generation circuit can both indicate whether there is a fault in the AC system based on the live wire output signal and the neutral wire output signal, and can also indicate whether there is a fault in the AC system based on the drive signal, thus realizing the multiplexing of the detection signal generation circuit. In addition, this meets the detection requirements for various fault types without designing independent detection circuits for each fault type, significantly improving the generality of the circuit and enabling it to flexibly handle various fault types that may occur in the three-phase AC system. Further, such a design effectively simplifies the circuit structure, reduces the occupied space and manufacturing cost, and avoids the complex connection and potential interference problems between multiple independent circuits, improving the robustness and reliability of the system.

[0138] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" throughout this specification are not necessarily all referring to the same embodiment, but may refer to the same embodiment. Moreover, in one or more embodiments, as will be apparent to those of ordinary skill in the art from this disclosure, the particular features, structures, or characteristics may be combined in any suitable manner.

[0139] Similarly, it should be appreciated that in the description of the exemplary embodiments of the present invention, for the purpose of streamlining the present disclosure and assisting in the understanding of one or more of the various inventive aspects, the various features of the present invention are sometimes grouped together in a single embodiment, drawing, or description thereof. However, this method of disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. On the contrary, as reflected by the appended claims, the inventive aspects lie in less than all of the features of a single foregoing disclosed embodiment. Accordingly, the appended claims of the present invention are hereby expressly incorporated into this detailed description, where each claim itself represents a separate embodiment of the present invention.

[0140] Moreover, although some embodiments described herein include some features included in other embodiments but not other features included in other embodiments, the combination of features of different embodiments is intended to fall within the scope of the present invention and form different embodiments as would be understood by those skilled in the art. For example, in the appended claims, any of the claimed embodiments can be used in any combination.

[0141] In the specification and claims, the terms "coupled" and "connected" and their derivatives may be used. It should be understood that these terms are not intended as synonyms for each other. Instead, in a particular embodiment, "connected" may be used to indicate that two or more elements are in direct physical or electrical contact with each other. "Coupled" may mean that two or more elements are in direct physical or electrical contact. However, "coupled" may also mean that two or more elements are not in direct contact with each other but still cooperate or interact with each other.

[0142] As used herein, a module refers to any combination of hardware, software, and / or firmware. As an example, a module includes hardware such as a microcontroller associated with a non-transitory medium for storing code adapted to be executed by the microcontroller. Thus, in one implementation, a reference to a module refers to hardware that is specifically configured to identify and / or execute code to be stored on a non-transitory medium. Additionally, in another implementation, the use of a module refers to a non-transitory medium that includes code specifically adapted to be executed by a microcontroller to perform a predetermined operation. And as can be inferred, in yet another implementation, the term module may refer to a combination of a microcontroller and a non-transitory medium. Generally, the boundaries of modules illustrated as separate may vary and potentially overlap. For example, a first module and a second module may share hardware, software, firmware, or a combination thereof while potentially retaining some separate hardware, software, or firmware.

[0143] Embodiments of the mechanisms disclosed herein may be implemented in hardware, software, firmware, or a combination of such implementations. Embodiments of the present invention may be implemented as a computer program or program code executed on a programmable system that includes at least one processor, a storage system (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device.

[0144] It will be apparent to those skilled in the art that various modifications and variations can be made to the above exemplary embodiments of the present invention without departing from the spirit and scope of the present invention. Accordingly, it is intended that the present invention cover modifications and variations of the present invention that fall within the scope of the appended claims and their equivalent technical solutions.

Claims

1. A detection circuit for a three-phase AC system, comprising: A drive circuit configured to receive an enable signal and generate a drive signal based on the enable signal; And A detection signal generation circuit including a neutral line signal input terminal and a plurality of live line signal input terminals. The detection signal generation circuit is electrically coupled to the output terminal of the neutral line relay of the AC system via the neutral line signal input terminal to receive a neutral line output signal from the output terminal of the neutral line relay, and is electrically coupled to the output terminals of a plurality of live line relays of the AC system via the plurality of live line signal input terminals to receive live line output signals from the output terminals of the plurality of live line relays. Wherein, the detection signal generation circuit is electrically coupled to the output terminal of the drive circuit via the plurality of live line signal input terminals, and is configured to generate a detection signal based on the live line output signal and the neutral line output signal, or based on the drive signal to indicate whether a fault exists in the AC system. The detection signal includes a plurality of live line detection signals corresponding to the plurality of live line relays and a neutral line detection signal corresponding to the neutral line relay.

2. The detection circuit according to claim 1, further comprising a control circuit configured to: Deactivate the drive circuit and indicate whether a first fault exists in the AC system based on the detection signal, wherein The detection signal generation circuit is configured to generate a detection signal based on the live line output signal and the neutral line output signal; Or Put the drive circuit in an active mode and indicate whether a second fault exists in the AC system based on the detection signal. Wherein, the detection signal generation circuit is configured to generate a detection signal based on the drive signal.

3. The detection circuit according to claim 2, wherein, The drive circuit includes: A drive signal generation circuit configured to receive an enable signal and generate a drive signal based on the enable signal; and A first isolation circuit including a plurality of disconnect switches. One ends of the plurality of disconnect switches are electrically coupled to the output terminal of the drive signal generation circuit respectively, and the detection signal generation circuit is electrically coupled to the other ends of the plurality of disconnect switches respectively via the plurality of live line signal input terminals.

4. The detection circuit according to claim 2, wherein, The drive circuit includes: A plurality of drive signal generation circuits, each of the plurality of drive signal generation circuits is configured to receive an enable signal and generate a drive signal based on the enable signal; and A second isolation circuit including a plurality of isolation capacitors. One ends of the plurality of isolation capacitors are electrically coupled to the output terminals of the plurality of drive signal generation circuits respectively, and the detection signal generation circuit is electrically coupled to the other ends of the plurality of isolation capacitors respectively via the plurality of live line signal input terminals.

5. The detection circuit according to claim 4, wherein, The detection circuit further includes an isolated power supply module configured to isolate a power supply signal to generate an isolated power supply signal, and the plurality of drive signal generation circuits are configured to be powered by the isolated power supply signal.

6. The detection circuit according to claim 3, wherein, The control circuit is configured to: Disconnect all the plurality of disconnect switches to put the drive circuit in the deactivated mode; Or An enable signal is provided to the drive signal generation circuit, and a selected one of the plurality of isolation switches is closed to place the drive circuit in the active mode.

7. The detection circuit according to claim 4, wherein, The control circuit is configured to: isolate the output signals of the plurality of drive signal generation circuits by the second isolation circuit to place the drive circuit in the deactivated mode; or provide an enable signal to a selected one of the plurality of drive signal generation circuits to place the drive circuit in the active mode.

8. The detection circuit according to any one of claims 6-7, wherein, The control circuit is configured to: place the drive circuit in the deactivated mode; determine whether the level of each of the detection signals is a first level; if it is determined that the level of each of the detection signals is the first level, indicate that the first fault does not exist in the AC system; if it is determined that the level of at least one of the detection signals is a second level, indicate that the first fault exists in the AC system.

9. The detection circuit according to claim 6, wherein The control circuit is configured to: place the drive circuit in the active mode; determine whether the level of the selected detection signal corresponding to the selected isolation switch among the detection signals is a second level and the levels of the remaining detection signals are first levels; if it is determined that the level of the selected detection signal is the second level and the levels of the remaining detection signals among the detection signals are the first levels, indicate that the second fault does not exist at the output terminal of the live wire relay corresponding to the selected detection signal.

10. The detection circuit according to claim 7, wherein, The control circuit is configured to: place the drive circuit in the active mode; determine whether the level of the selected detection signal corresponding to the selected drive signal generation circuit among the detection signals is a second level and the levels of the remaining detection signals are first levels; if it is determined that the level of the selected detection signal is the second level and the levels of the remaining detection signals among the detection signals are the first levels, indicate that the second fault does not exist at the output terminal of the live wire relay corresponding to the selected detection signal.

11. The detection circuit according to any one of claims 9-10, wherein, The control circuit is configured to: if it is determined that the level of the selected detection signal is the first level, or if it is determined that the level of the selected detection signal is the second level and the level of any one of the remaining detection signals among the detection signals is the second level, indicate that the second fault exists in the AC system.

12. The detection circuit according to claim 11, wherein, The control circuit is configured to: if it is determined that the level of the selected detection signal is the first level, indicate that there is a short circuit between the live wire and the ground at the output terminal of the live wire relay corresponding to the selected detection signal; if it is determined that the level of the selected detection signal is the second level and the level of any one of the remaining detection signals among the detection signals is the second level, indicate that there is a phase-to-phase short circuit between the output terminal of the live wire relay corresponding to the selected detection signal and the relay corresponding to the remaining detection signal having the second level.

13. The detection circuit according to claim 1, wherein, The enable signal is a pulse width modulation (PWM) signal.

14. A power supply device, comprising: A plurality of live wire relays and neutral wire relays disposed on the live wire and the neutral wire in a three-phase AC system; And The detection circuit according to any one of claims 1-13.

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