A detection circuit for detecting sticking of a relay and a power adapter

Abstract

The application provides a detection circuit for sticking of a relay and a power adapter, and relates to the technical field of circuits.The detection circuit is connected with two ends of a first relay and two ends of a second relay, and whether the first relay sticks can be judged by comparing the voltage detected by one detection branch in the detection circuit with the output voltage of a power supply; whether the second relay sticks can be judged by comparing the voltage detected by another detection branch in the detection circuit with the output voltage of the power supply. The detection method for sticking does not need to change the structure of the relay, can avoid increasing the manufacturing cost and volume of the relay, and thus realizes the detection of sticking on the basis of keeping the original structure unchanged.

Description

Technical Field

[0001] This application relates to the field of circuit technology, and in particular to a detection circuit for relay sticking and a power adapter. Background Technology

[0002] When the AC power grid supplies power to the converter, the AC power grid and the converter are connected via neutral and live wires, each equipped with a relay to control the switching on and off of the neutral and live wires. A relay is a switching device that maintains a certain insulation distance when disconnected. Although the contacts in a relay have a certain withstand capability against overcurrent, they can stick together under special circumstances, affecting electrical safety. Therefore, for safety and reliability, it is necessary to detect relay sticking. Current sticking detection methods generally involve adding auxiliary contacts to the relay. While this method achieves the purpose of sticking detection, it increases the manufacturing cost and size of the relay. Summary of the Invention

[0003] This application provides a detection circuit and power adapter for relay sticking, which can detect whether the relay is stuck, while avoiding increasing the manufacturing cost and size of the relay.

[0004] In a first aspect, embodiments of this application provide a detection circuit. In two lines between a power source and a load, one line has a first relay and the other line has a second relay. The detection circuit may include two detection branches. If the end of the first relay facing the power source is designated as the first node, the end of the first relay facing the load is designated as the second node, the end of the second relay facing the power source is designated as the third node, and the end of the second relay facing the load is designated as the fourth node, one detection branch (which may be called the first detection branch) is connected to the first node, the second node, and the third node respectively, and the other detection branch (which may be called the second detection branch) is connected to the third node, the fourth node, and the first node respectively.

[0005] When both the first and second relays are open and the power supply outputs a signal, current can flow through the first and second detection branches. At this time, the first detection branch can: detect the voltage between the first and second nodes, or the voltage between the second and third nodes, or the voltage between the first and second nodes and the voltage between the second and third nodes. The second detection branch can: detect the voltage between the third and fourth nodes, or the voltage between the first and fourth nodes, or the voltage between the third and fourth nodes and the voltage between the first and fourth nodes. Thus, each detection branch can detect at least one of the following: the voltage between the two ends of the corresponding relay, and the voltage between one end of the first relay and the other end of the second relay. One end of the first relay and the other end of the second relay face the power supply, and the other faces the load.

[0006] Based on this, when determining the output voltage of the power supply, the first relay can be determined to be stuck by comparing the voltage detected by the first detection branch with the output voltage. Similarly, the second relay can be determined to be stuck by comparing the voltage detected by the second detection branch with the output voltage. This allows for the detection of the sticking status of each relay. Furthermore, in this application, the sticking status of each relay can be detected through the detection circuit without changing the structure of the relay itself. Therefore, it avoids increasing the manufacturing cost and size of the relays, achieving sticking detection while maintaining the original structure.

[0007] Furthermore, when detecting voltage, detection can be performed according to the set acquisition period, or detection can be triggered at any time as needed. Since voltage detection is not limited by the energizing sequence and interval of the two relays, the detection efficiency can be improved, thereby improving the efficiency of relay judgment.

[0008] In some embodiments, the first detection branch includes a first impedance unit, a second impedance unit, and a first voltage acquisition unit. The first impedance unit is connected to a first node and a second node, respectively, and the second impedance unit is connected to a second node and a third node, respectively.

[0009] When the first detection branch is used to detect the voltage between the first and second nodes but not the voltage between the second and third nodes, one first voltage acquisition unit can be provided, and this first voltage acquisition unit is connected to the first impedance unit. Alternatively, when the first detection branch is used to detect the voltage between the second and third nodes but not the voltage between the first and second nodes, one first voltage acquisition unit can also be provided, and this first voltage acquisition unit is connected to the second impedance unit. Or, when the first detection branch is used to detect both the voltage between the first and second nodes and the voltage between the second and third nodes, two first voltage acquisition units can be provided, one of which is connected to the first impedance unit, and the other is connected to the second impedance unit.

[0010] Thus, when the first relay sticks, the first and second nodes are short-circuited, making their potentials the same or nearly the same. Therefore, the current will not flow through the first impedance unit but will flow directly from the first node to the second node. If the first voltage acquisition unit is connected to the first impedance unit, the acquired voltage will be zero, close to zero, or a value very small compared to the output voltage. In this case, it can be determined that the first relay has stuck. If the first voltage acquisition unit is connected to the second impedance unit, since the second impedance unit is connected to both the second and third nodes, and the potentials of the second and first nodes are almost the same, the voltage acquired by the first voltage acquisition unit is close to the power supply's output voltage. When compared with the output voltage, if the acquired voltage is very close to the output voltage, it can be determined that the first relay has stuck.

[0011] When the first relay is normally disconnected, the first and second nodes are completely disconnected, so the impedance between them is very large, and current will flow through the first impedance unit. If the first voltage acquisition unit is connected to the first impedance unit, the voltage acquired is the voltage drop generated by the first impedance unit. If the first voltage acquisition unit is connected to the second impedance unit, the voltage acquired is the voltage drop generated by the second impedance unit. By comparing this voltage with the output voltage, it can be determined that the first relay is normally disconnected.

[0012] In some embodiments, the second detection branch includes a third impedance unit, a fourth impedance unit, and a second voltage acquisition unit. The third impedance unit is connected to the third node and the fourth node, respectively, and the fourth impedance unit is connected to the fourth node and the first node, respectively.

[0013] When the second detection branch is used to detect the voltage between the third and fourth nodes but not the voltage between the fourth and first nodes, one second voltage acquisition unit may be provided, and this second voltage acquisition unit is connected to the third impedance unit. Alternatively, when the second detection branch is used to detect the voltage between the fourth and first nodes but not the voltage between the third and fourth nodes, one second voltage acquisition unit may be provided, and this second voltage acquisition unit is connected to the fourth impedance unit. Or, when the second detection branch is used to detect both the voltage between the third and fourth nodes and the voltage between the fourth and first nodes, two second voltage acquisition units may be provided, one of which is connected to the third impedance unit, and the other is connected to the fourth impedance unit.

[0014] Thus, when the second relay sticks, the third and fourth nodes are short-circuited, making their potentials the same or nearly the same. Therefore, the current will not flow through the third impedance unit but will flow directly from the fourth node to the third node. If the second voltage acquisition unit is connected to the third impedance unit, the acquired voltage will be zero, close to zero, or a value very small compared to the output voltage. In this case, it can be determined that the second relay has stuck. If the second voltage acquisition unit is connected to the fourth impedance unit, since the fourth impedance unit is connected to both the first and fourth nodes, and the potentials of the fourth and third nodes are almost the same, the voltage acquired by the second voltage acquisition unit is close to the power supply's output voltage. When compared with the output voltage, if the acquired voltage is very close to the output voltage, it can be determined that the second relay has stuck.

[0015] When the second relay is normally disconnected, the third and fourth nodes are completely disconnected, so the impedance between them is very large, and current will flow through the third impedance unit. If the second voltage acquisition unit is connected to the third impedance unit, the voltage acquired is the voltage drop generated by the third impedance unit. If the second voltage acquisition unit is connected to the fourth impedance unit, the voltage acquired is the voltage drop generated by the fourth impedance unit. At this point, it can be determined that the second relay is normally disconnected.

[0016] In some embodiments, a filter capacitor is typically installed between the two lines. This filter capacitor has the characteristic of passing AC signals and blocking DC signals. Therefore, when the power supply outputs an AC signal, the AC signal can pass through the filter capacitor, and the impedance value of the filter capacitor is generally not very large, or in other words, the impedance value of the filter capacitor is generally much smaller than the impedance values ​​of the first impedance unit, the second impedance unit, the third impedance unit, and the fourth impedance unit. When the power supply outputs a DC signal, the filter capacitor can be regarded as a very large impedance, and the DC signal generally will not pass through the filter capacitor. Therefore, when the type of signal output by the power supply is different, there will be differences in the adhesion judgment based on the voltages collected by the first voltage acquisition unit and the second voltage acquisition unit, as detailed below:

[0017] Taking the connection between the first voltage acquisition unit and the second impedance unit, and the connection between the second voltage acquisition unit and the third impedance unit as an example:

[0018] 1. Power supply outputs AC signal.

[0019] 1.1 The first relay disconnects normally, while the second relay sticks.

[0020] If the first relay is normally disconnected and the second relay is stuck, because the filter capacitor is connected in parallel with the second impedance unit, and the impedance of the filter capacitor is much smaller than that of the second impedance unit, the AC signal will return to the power supply after passing through the first impedance unit and the filter capacitor. Very little AC signal will flow through the second impedance unit, making the current flowing through it relatively small and close to zero. Therefore, the voltage drop across the second impedance unit measured by the first voltage acquisition unit is very small or close to zero compared to the output voltage. When the second voltage acquisition unit is connected to the third impedance unit, because the second relay is stuck, the voltage measured is also very small or close to zero compared to the output voltage. Therefore, when the voltages measured by both the first and second voltage acquisition units are very small or close to zero compared to the output voltage, it can be determined that the first relay is normally disconnected and the second relay is stuck.

[0021] 1.2 The first relay is stuck together, while the second relay disconnects normally.

[0022] If the first relay is stuck and the second relay is normally open, since the second impedance unit is connected to both the second and third nodes, when the potentials of the first and second nodes are the same, the voltage divided by the second impedance unit is the voltage between the first and third nodes. Since the voltage between the first and third nodes is the output voltage, the voltage divided by the second impedance unit is also the output voltage. When the first voltage acquisition unit is connected to the second impedance unit, the acquired voltage is close to the output voltage. Because the first relay is stuck, the fourth impedance unit and the filter capacitor are connected in parallel. When the impedance of the filter capacitor is much smaller than the impedance of the fourth impedance unit, the current flowing through the fourth impedance unit is very small. We can temporarily assume that the current flowing through the fourth impedance unit is zero, and therefore, we can temporarily assume that the voltage divided by the fourth impedance unit is zero. When the second relay is normally open, the power supply, filter capacitor, and third impedance unit can form a current loop. When the impedance of the filter capacitor is much smaller than the impedance of the fourth impedance unit, the voltage divided by the third impedance unit is close to the output voltage. Therefore, when the second voltage acquisition unit is connected to the third impedance unit, the acquired voltage is close to the output voltage. Therefore, when the voltages acquired by the first voltage acquisition unit and the second voltage acquisition unit are both close to the output voltage, it can be determined that the first relay is stuck and the second relay is normally disconnected.

[0023] 1.3 The first relay is stuck together, and the second relay is stuck together.

[0024] If the first relay is stuck, and the second relay is stuck, similarly, if the voltage collected by the first voltage acquisition unit is close to the output voltage, and the voltage collected by the second voltage acquisition unit is very small or close to zero compared to the output voltage, then it can be determined that the first relay is stuck and the second relay is stuck.

[0025] 1.4 The first relay disconnects normally, and the second relay disconnects normally.

[0026] If both the first and second relays open normally, the AC signal will pass through the first and second detection branches respectively. Therefore, when the first voltage acquisition unit is connected to the second impedance unit, the acquired voltage is the voltage division between the first and second impedance units. If the impedance of the first impedance unit is represented by R1, the impedance of the second impedance unit by R2, and the output voltage by Vs, the acquired voltage is approximately R2*Vs / (R1+R2). When the second voltage acquisition unit is connected to the third impedance unit, the acquired voltage is the voltage division between the third and fourth impedance units. If the impedance of the third impedance unit is represented by R3, and the impedance of the fourth impedance unit by R4, the acquired voltage is approximately R3*Vs / (R3+R4). Therefore, when the voltage acquired by the first voltage acquisition unit is approximately R2*Vs / (R1+R2) and the voltage acquired by the second voltage acquisition unit is approximately R3*Vs / (R3+R4), it can be determined that both the first and second relays are open normally.

[0027] 2. The power supply outputs a DC signal.

[0028] 2.1 The first relay disconnects normally, while the second relay sticks.

[0029] If the first relay is normally disconnected and the second relay is stuck, although the filter capacitor is connected in parallel with the second impedance unit, the impedance of the filter capacitor is much larger than that of the second impedance unit. Therefore, the DC signal passes through the first impedance unit and then through the second impedance unit back to the power supply. Thus, the voltage acquired by the first voltage acquisition unit is the voltage division between the first and second impedance units. When the impedance of the first impedance unit is represented by R1, the impedance of the second impedance unit by R2, and the output voltage by Vs, the acquired voltage is close to R2*Vs / (R1+R2). When the second voltage acquisition unit is connected to the third impedance unit, due to the second relay being stuck, the acquired voltage is very small or close to zero compared to the output voltage. Therefore, when the voltage acquired by the first voltage acquisition unit is close to R2*Vs / (R1+R2), and the voltage acquired by the second voltage acquisition unit is very small or close to zero compared to the output voltage, it can be determined that the first relay is normally disconnected and the second relay is stuck.

[0030] 2.2 The first relay is stuck together, while the second relay disconnects normally.

[0031] If the first relay is stuck, the second relay will normally disconnect. Since the second impedance unit is connected to both the second and third nodes, when the potentials of the first and second nodes are the same, the voltage division of the second impedance unit is the voltage between the first and third nodes. Because the voltage between the first and third nodes is the output voltage, the voltage division of the second impedance unit is also the output voltage. When the first voltage acquisition unit is connected to the second impedance unit, the acquired voltage is close to the output voltage. Due to the first relay being stuck, the fourth impedance unit and the filter capacitor are connected in parallel. When the impedance value of the filter capacitor is much greater than the impedance value of the fourth impedance unit, the current flowing through the filter capacitor is very small and close to zero. Therefore, the fourth impedance unit, the third impedance unit, and the power supply can form a current loop. When the second voltage acquisition unit is connected to the third impedance unit, the acquired voltage is close to the voltage division of the third impedance unit between the third and fourth impedance units. When the impedance of the third impedance unit is represented by R3 and the impedance of the fourth impedance unit is represented by R4, the acquired voltage is close to R3*Vs / (R3+R4). Therefore, if the voltage acquired by the first voltage acquisition unit is close to the output voltage, and the voltage acquired by the second voltage acquisition unit is close to R3*Vs / (R3+R4), it can be determined that the first relay is stuck and the second relay is normally disconnected.

[0032] 2.3 The first relay is stuck together, and the second relay is stuck together.

[0033] If the first relay is stuck, and the second relay is stuck, similarly, if the voltage collected by the first voltage acquisition unit is close to the output voltage, and the voltage collected by the second voltage acquisition unit is very small or close to zero compared to the output voltage, then it can be determined that the first relay is stuck and the second relay is stuck.

[0034] 2.4 The first relay disconnects normally, and the second relay disconnects normally.

[0035] If both the first and second relays open normally, similarly, when the first voltage acquisition unit is connected to the second impedance unit, the acquired voltage is the voltage division between the first and second impedance units, i.e., R2*Vs / (R1+R2). When the second voltage acquisition unit is connected to the third impedance unit, the acquired voltage is close to the voltage division between the third and fourth impedance units, i.e., R3*Vs / (R3+R4). Therefore, if the voltage acquired by the first voltage acquisition unit is close to R2*Vs / (R1+R2) and the voltage acquired by the second voltage acquisition unit is close to R3*Vs / (R3+R4), it can be determined that both the first and second relays are open normally.

[0036] Therefore, the detection circuit provided in this application embodiment can be applied not only to AC scenarios but also to DC scenarios. Moreover, especially in scenarios where the input fluctuates frequently, the detection circuit can adjust the potential of the contacts of the two relays to ground to avoid the influence of the Y capacitor, thereby ensuring the normal operation of the two relays.

[0037] In some embodiments, the impedance values ​​of the first, second, third, and fourth impedance units can be set to be the same. In this case, it is sufficient to directly determine whether the voltages acquired by the first and second voltage acquisition units are close to zero, or whether the output voltage is half of the output voltage, thereby simplifying the calculation and improving the judgment efficiency. Of course, the impedance values ​​of the first, second, third, and fourth impedance units can also be set to be at least partially different. This allows the impedance values ​​of each impedance unit to be adjusted according to actual needs to meet the requirements of different application scenarios and improve the design flexibility.

[0038] In some embodiments, when the power supply is used to output an AC signal, at least one of the first impedance unit, the second impedance unit, the third impedance unit, and the fourth impedance unit may include at least one of an inductor, a resistor, and a capacitor; when the power supply is used to output a DC signal, at least one of the first impedance unit, the second impedance unit, the third impedance unit, and the fourth impedance unit may include at least one of a resistor and a capacitor. This allows the structure of each impedance unit to be configured for different application scenarios, thereby improving design flexibility.

[0039] Furthermore, the structures of the first impedance unit, the second impedance unit, the third impedance unit, and the fourth impedance unit can all be set to be the same to simplify the structure of the detection circuit and reduce the manufacturing difficulty and cost of the detection circuit. Of course, the structures of the first impedance unit, the second impedance unit, the third impedance unit, and the fourth impedance unit can also be set to be at least partially different to meet the needs of different application scenarios and improve the flexibility of the design.

[0040] In some embodiments, the output voltage of the power supply can be obtained from the power supplier, or a third voltage acquisition unit can be connected between the two lines to acquire the output voltage. Furthermore, the first, second, and third voltage acquisition units can all be identical in structure to simplify the detection circuit structure and reduce its fabrication difficulty and cost. Alternatively, their structures can be at least partially different to meet the needs of different application scenarios and improve design flexibility. It should be understood that when the third voltage acquisition unit is not provided, the first and second voltage acquisition units can have identical or different structures.

[0041] In some embodiments, when the first voltage acquisition unit is connected to the first impedance unit, the first impedance unit can be a part of the first voltage acquisition unit, that is, the first impedance unit and the first voltage acquisition unit belong to the same independent device; or, when the first voltage acquisition unit is connected to the second impedance unit, the second impedance unit can be a part of the first voltage acquisition unit, that is, the second impedance unit and the first voltage acquisition unit belong to the same independent device. Similarly, when the second voltage acquisition unit is connected to the third impedance unit, the third impedance unit can be a part of the second voltage acquisition unit, that is, the third impedance unit and the second voltage acquisition unit belong to the same independent device; or, when the second voltage acquisition unit is connected to the fourth impedance unit, the fourth impedance unit can be a part of the second voltage acquisition unit, that is, the fourth impedance unit and the second voltage acquisition unit belong to the same independent device.

[0042] In some embodiments, the specific structures of the first voltage acquisition unit, the second voltage acquisition unit, and the third voltage acquisition unit are not limited herein, and any structure that can realize voltage acquisition is within the protection scope of the embodiments of this application.

[0043] Secondly, embodiments of this application also provide a power adapter, including: a first relay, a second relay, a detection circuit, a converter, and a processor; one of the two lines connected to the converter has a first relay and the other has a second relay; the detection circuit is connected to a first terminal and a second terminal of the first relay, a first terminal and a second terminal of the second relay, and the processor; wherein, the detection circuit can be used to: detect at least one of the voltage between the two terminals of the first relay and the voltage between the first terminal of the first relay and the second terminal of the second relay when both the first relay and the second relay are disconnected and current flows through both lines and the detection circuit; detect at least one of the voltage between the two terminals of the second relay and the voltage between the first terminal of the second relay and the second terminal of the first relay; and transmit the detected voltage to the processor, which can be used to determine whether the first relay and the second relay are stuck together based on the voltage detected by the detection circuit and the voltage between the two lines.

[0044] Wherein, when the first terminal of the first relay and the first terminal of the second relay are both located on the side facing the converter, the second terminal of the first relay and the second terminal of the second relay are both located on the side away from the converter; or, when the first terminal of the first relay and the first terminal of the second relay are both located on the side away from the converter, the second terminal of the first relay and the second terminal of the second relay are both located on the side facing the converter.

[0045] In this way, by comparing the voltage detected by the detection circuit with the voltage between the two lines, it can be determined whether the relays have stuck together. This method of detecting sticking does not require changing the structure of the relays themselves, thus avoiding increasing the manufacturing cost and size of the relays, achieving sticking detection while maintaining the original structure. Furthermore, when detecting voltage, detection can be performed according to a set sampling period, or it can be triggered at any time as needed. Since voltage detection is not limited by the energizing sequence or interval of the two relays, the detection efficiency can be improved, thereby improving the efficiency of relay judgment.

[0046] The specific implementation principle of the detection circuit in this power adapter is similar to that of the aforementioned detection circuit. For the specific implementation method of the detection circuit in this power adapter, please refer to the specific embodiment of the aforementioned detection circuit. Repeated details will not be repeated.

[0047] In some embodiments, when the power adapter is located between the power source and the load, the converter is connected to both the power source and the load. In this case, the converter can perform voltage and power conversion processing on the signal output from the power source before transmitting it to the load for use and to drive the load to operate. The power source can be an AC source providing AC signals or a DC source providing DC signals. The AC source can be, but is not limited to, an AC power grid or an AC charging station, while the DC source can be, but is not limited to, a photovoltaic power source or a DC charging station. Furthermore, if a first relay and a second relay are respectively provided in the two lines between the converter and the power source, the detection circuit can be connected to each of the two lines between the converter and the power source. In this case, the voltage between the two lines can be considered the output voltage of the power source. Similarly, if a first relay and a second relay are respectively provided in the two lines between the converter and the load, the detection circuit can be connected to each of the two lines between the converter and the load. In this case, the voltage between the two lines can be considered the output voltage of the converter.

[0048] In some embodiments, when the detection circuit includes two detection branches, each detection branch can detect voltage. One detection branch is used to detect at least one of the voltage between the first and second terminals of the first relay and the voltage between the first and second terminals of the first relay; the other detection branch is used to detect at least one of the voltage between the first and second terminals of the second relay and the voltage between the first and second terminals of the second relay. The processor can then calculate the difference between the voltages detected by the two detection branches, and based on the difference and the voltage between the two lines, further determine whether the first and second relays are stuck together. This allows for further determination of whether they are stuck together, improving the accuracy of the determination result. Attached Figure Description

[0049] Figure 1 This is a structural diagram of an electricity consumption scenario provided in an embodiment of this application;

[0050] Figure 2 This is a schematic diagram of a detection circuit provided in an embodiment of this application;

[0051] Figure 3 This is a schematic diagram of another detection circuit provided in an embodiment of this application;

[0052] Figure 4 A flowchart of the detection method provided in the embodiments of this application;

[0053] Figure 5 This is a schematic diagram of the structure of a power adapter provided in an embodiment of this application;

[0054] Figure 6 This is a schematic diagram of another power adapter provided in an embodiment of this application.

[0055] Figure label:

[0056] m1-Power supply, m2-Load, m3-Power adapter, k0-Relay, k1-First relay, k2-Second relay, L-Neutral wire, N-Live wire, x+-Positive busbar, x--Negative busbar, 100-Detection circuit, 10-First detection branch, 11-First impedance unit, 12-Second impedance unit, 13-First voltage acquisition unit, 20-Second detection branch, 21-Third impedance unit, 22-Fourth impedance unit, 23-Second voltage acquisition unit, 30-Third voltage acquisition unit, 200-Processor, 300-Converter. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0058] It should be noted that the same reference numerals in the accompanying drawings of this application denote the same or similar structures, and therefore repeated descriptions of them will be omitted. Terms expressing position and direction described in this application are illustrative based on the accompanying drawings, but may be modified as needed, and all such modifications are included within the scope of protection of this application. The accompanying drawings of this application are for illustrating relative positional relationships only and do not represent actual scale.

[0059] First, the application scenarios of this application will be introduced.

[0060] like Figure 1The schematic diagram of the power consumption scenario shown illustrates that when power source m1 is an AC source, it can be connected to converter 300 via neutral wire L and live wire N. Converter 300 can be connected to load m2 via positive bus x+ and negative bus x-. Converter 300 is used to perform voltage and power conversion on the AC signal provided by the AC source to obtain a DC signal for driving load m2. Of course, power source m1 can also be a DC source, in which case power source m1 is connected to converter 300 via positive and negative buses. It should be understood that neutral wire L and live wire N, as well as positive bus x+ and negative bus x-, can all be collectively referred to as two lines.

[0061] Relays k0 are installed in the neutral line L, live line N, positive bus x+, and negative bus x-. When both relays k0 in the neutral line L and live line N are open, if at least one of these two relays k0 becomes stuck, the power supply m1 cannot be effectively disconnected from the converter 300. When both relays k0 in the positive bus x+ and negative bus x- are open, if at least one of these two relays k0 becomes stuck, the AC converter 300 cannot be effectively disconnected from the load m2, which will affect electrical safety. Therefore, from a safety and reliability perspective, it is necessary to detect relay sticking. Current sticking detection methods generally use auxiliary contacts added to the relays to achieve sticking detection. While this method can achieve the purpose of sticking detection, it increases the manufacturing cost and size of the relays.

[0062] This application provides a detection circuit that can be positioned between a power supply and a converter to detect whether two relays between the power supply and the converter have become stuck together. Alternatively, the detection circuit can be positioned between the converter and the load to detect whether two relays between the converter and the load have become stuck together. This method of detecting sticking does not require changing the structure of the relays themselves, thus avoiding increasing the manufacturing cost and size of the relays, and achieving sticking detection while maintaining the original structure.

[0063] The detection circuit is described in detail below.

[0064] This application can be applied to, for example... Figure 2 and Figure 3 In the schematic diagram of the detection circuit shown, as Figure 2 and Figure 3As shown, in the two lines between the power source m1 and the load m2, one line has a first relay (denoted as k1), and the other line has a second relay (denoted as k2). The end of the first relay k1 facing the power source m1 is designated as the first node P1, the end of the first relay k1 facing the load m2 is designated as the second node P2, the end of the second relay k2 facing the power source m1 is designated as the third node P3, and the end of the second relay k2 facing the load m2 is designated as the fourth node P4. One detection branch (which can be called the first detection branch) 10 in the detection circuit 100 is connected to the first node P1, the second node P2, and the third node P3 respectively. The other detection branch (which can be called the second circuit detection branch) 20 in the detection circuit 100 is connected to the third node P3, the fourth node P4, and the first node P1 respectively.

[0065] When both the first relay k1 and the second relay k2 are disconnected and the power supply m1 outputs a signal, current can flow through the first detection branch 10 and the second detection branch 20. At this time, the first detection branch 10 can: detect the voltage between the first node P1 and the second node P2, or detect the voltage between the second node P2 and the third node P3 (i.e., detect the voltage between two lines), or detect the voltage between the first node P1 and the second node P2, as well as the voltage between the second node P2 and the third node P3. The second detection branch 20 can: detect the voltage between the third node P3 and the fourth node P4, or detect the voltage between the first node P1 and the fourth node P4 (i.e., detect the voltage between two lines), or detect the voltage between the third node P3 and the fourth node P4, as well as the voltage between the first node P1 and the fourth node P4.

[0066] Based on this, when determining the output voltage of power supply m1, the voltage detected by the first detection branch 10 is compared with the output voltage to determine whether the first relay k1 is stuck. Similarly, the voltage detected by the second detection branch 20 is compared with the output voltage to determine whether the second relay k2 is stuck, thus enabling the detection of the sticking status of each relay. Furthermore, in this application, the sticking status of each relay can be detected through the detection circuit without altering the relay's structure, thereby avoiding increased manufacturing costs and size. Sticking detection is achieved while maintaining the original structure. Additionally, voltage detection can be performed according to a set acquisition period or triggered at any time as needed. Since voltage detection is not limited by the energizing sequence or interval of the two relays, detection efficiency is improved, thereby enhancing the efficiency of relay judgment.

[0067] In some embodiments, such as Figure 2 and Figure 3 As shown, the first detection branch 10 includes a first impedance unit 11, a second impedance unit 12 and a first voltage acquisition unit 13. The first impedance unit 11 is connected to the first node P1 and the second node P2 respectively, and the second impedance unit 12 is connected to the second node P2 and the third node P3 respectively.

[0068] When the first detection branch 10 is used to detect the voltage between the first node P1 and the second node P2 without detecting the voltage between the second node P2 and the third node P3, a first voltage acquisition unit 13 can be provided, and this first voltage acquisition unit 13 is connected to the first impedance unit 11, such as... Figure 2 As shown. Alternatively, when the first detection branch 10 is used to detect the voltage between the second node P2 and the third node P3 without detecting the voltage between the first node P1 and the second node P2, a first voltage acquisition unit 13 can also be provided, and this first voltage acquisition unit 13 is connected to the second impedance unit 12, as shown. Figure 3 As shown. Alternatively, when the first detection branch 10 is used to detect the voltage between the first node P1 and the second node P2, as well as the voltage between the second node P2 and the third node P3, two first voltage acquisition units 13 can be provided. One first voltage acquisition unit 13 is connected to the first impedance unit 11, and the other first voltage acquisition unit 13 is connected to the second impedance unit 12, which is not shown in the figure.

[0069] Thus, when the first relay k1 sticks together, the first node P1 and the second node P2 are short-circuited, making their potentials the same or approximately the same. Therefore, the current will not flow through the first impedance unit 11 but will flow directly from the first node P1 to the second node P2. If the first voltage acquisition unit 13 is connected to the first impedance unit 11, such as... Figure 2 As shown, the voltage collected at this time will be zero, close to zero, or a value very small compared to the output voltage. In this case, it can be determined that the first relay k1 has become stuck. If the first voltage acquisition unit 13 is connected to the second impedance unit 12, as shown... Figure 3 As shown, since the second impedance unit 12 is connected to the second node P2 and the third node P3 respectively, and the potentials of the second node P2 and the first node P1 are almost the same, the voltage collected by the first voltage acquisition unit 13 is close to the output voltage of the power supply m1. Then, it is compared with the output voltage. If the collected voltage is close to the output voltage, it can be determined that the first relay k1 has stuck.

[0070] When the first relay k1 is normally disconnected, the first node P1 and the second node P2 are completely disconnected, so the impedance between them is very large, and current will flow through the first impedance unit 11. If the first voltage acquisition unit 13 is connected to the first impedance unit 11, such as... Figure 2 As shown, the voltage collected at this time is the voltage drop generated by the first impedance unit 11. If the first voltage acquisition unit 13 is connected to the second impedance unit 12, as shown... Figure 3 As shown, the voltage collected at this time is the voltage drop generated by the second impedance unit 12. By comparing it with the output voltage, it can be determined that the first relay k1 is normally disconnected.

[0071] In some embodiments, such as Figure 2 and Figure 3 As shown, the second detection branch 20 includes a third impedance unit 21, a fourth impedance unit 22, and a second voltage acquisition unit 23. The third impedance unit 21 is connected to the third node P3 and the fourth node P4, respectively, and the fourth impedance unit 22 is connected to the fourth node P4 and the first node P1, respectively.

[0072] When the second detection branch 20 is used to detect the voltage between the third node P3 and the fourth node P4 without detecting the voltage between the fourth node P4 and the first node P1, a second voltage acquisition unit 23 can be provided, and this second voltage acquisition unit 23 is connected to the third impedance unit 21, such as... Figure 3 As shown. Alternatively, when the second detection branch 20 is used to detect the voltage between the fourth node P4 and the first node P1 without detecting the voltage between the third node P3 and the fourth node P4, a second voltage acquisition unit 23 can be provided, and this second voltage acquisition unit 23 is connected to the fourth impedance unit 22, as shown. Figure 2 As shown. Alternatively, when the second detection branch 20 is used to detect the voltage between the third node P3 and the fourth node P4, as well as the voltage between the fourth node P4 and the first node P1, two second voltage acquisition units 23 are provided. One second voltage acquisition unit 23 is connected to the third impedance unit 21, and the other second voltage acquisition unit 23 is connected to the fourth impedance unit 22, which is not shown in the figure.

[0073] Thus, when the second relay k2 sticks, the third node P3 and the fourth node P4 are short-circuited, making their potentials the same or approximately the same. Therefore, the current will not flow through the third impedance unit 21 but will flow directly from the fourth node P4 to the third node P3. If the second voltage acquisition unit 23 is connected to the third impedance unit 21, as shown in the example... Figure 3 As shown, the voltage collected at this time will be zero, close to zero, or a value very small compared to the output voltage. In this case, it can be determined that the second relay k2 has become stuck. If the second voltage acquisition unit 23 is connected to the fourth impedance unit 22, as shown... Figure 2As shown, since the fourth impedance unit 22 is connected to the first node P1 and the fourth node P4 respectively, and the potentials of the fourth node P4 and the third node P3 are almost the same, the voltage collected by the second voltage acquisition unit 23 is close to the output voltage of the power supply m1. Then, it is compared with the output voltage. If the collected voltage is close to the output voltage, it can be determined that the second relay k2 has stuck.

[0074] When the second relay k2 is normally disconnected, the third node P3 and the fourth node P4 are completely disconnected, so the impedance between them is very large, and current will flow through the third impedance unit 21. If the second voltage acquisition unit 23 is connected to the third impedance unit 21, such as... Figure 3 As shown, the voltage collected at this time is the voltage drop generated by the third impedance unit 21. If the second voltage acquisition unit 23 is connected to the fourth impedance unit 22, as shown... Figure 2 As shown, the voltage collected at this time is the voltage drop generated by the fourth impedance unit 22, and it can be determined that the second relay k2 is normally disconnected.

[0075] It should be understood that the setting of the second detection branch is not limited by the setting method of the first detection branch, and similarly, the setting of the first detection branch is not limited by the setting method of the second detection branch. The first and second detection branches can be set independently according to actual needs.

[0076] by Figure 3 Taking the structure shown as an example, a filter capacitor C0 can also be provided between the two lines. This filter capacitor C0 has the characteristic of passing AC signals and blocking DC signals. Therefore, when power supply m1 outputs an AC signal, the AC signal can pass through the filter capacitor C0, and the impedance value of the filter capacitor C0 is generally not very large, or in other words, the impedance value of the filter capacitor C0 is generally much smaller than the impedance values ​​of the first impedance unit 11, the second impedance unit 12, the third impedance unit 21, and the fourth impedance unit 22. When power supply m1 outputs a DC signal, the filter capacitor C0 can be considered as a very large impedance, and the DC signal generally will not pass through this filter capacitor C0. Therefore, when the type of signal output by power supply m1 is different, there will be differences in the adhesion judgment based on the voltages collected by the first voltage acquisition unit 13 and the second voltage acquisition unit 23, as detailed below:

[0077] 1. Power supply m1 outputs AC signal.

[0078] If the first relay k1 is normally disconnected and the second relay k2 is stuck, because the filter capacitor C0 is connected in parallel with the second impedance unit 12, and the impedance value of the filter capacitor C0 is much smaller than that of the second impedance unit 12, the AC signal will return to the power supply m1 after passing through the first impedance unit 11 and the filter capacitor C0. Very little AC signal will flow through the second impedance unit 12, making the current flowing through the second impedance unit 12 relatively small and close to zero. Therefore, when the first voltage acquisition unit 13 is connected to the second impedance unit 12, the voltage division of the second impedance unit 12 acquired is very small or close to zero compared to the output voltage. When the second voltage acquisition unit 23 is connected to the third impedance unit 21, because the second relay k2 is stuck, the acquired voltage is also very small or close to zero compared to the output voltage.

[0079] If the first relay k1 is stuck and the second relay k2 is normally disconnected, since the second impedance unit 12 is connected to the second node P2 and the third node P3 respectively, when the potentials of the first node P1 and the second node P2 are the same, the voltage division of the second impedance unit 12 is the voltage between the first node P1 and the third node P3. Since the voltage between the first node P1 and the third node P3 is the output voltage, the voltage division of the second impedance unit 12 is the output voltage. When the first voltage acquisition unit 13 is connected to the second impedance unit 12, the acquired voltage is close to the output voltage. Because the first relay k1 is stuck, the fourth impedance unit 22 and the filter capacitor C0 are connected in parallel. When the impedance value of the filter capacitor C0 is much smaller than the impedance value of the fourth impedance unit 22, the current flowing through the fourth impedance unit 22 is very small. At this time, it is temporarily assumed that the current flowing through the fourth impedance unit 22 is zero, and thus the voltage division of the fourth impedance unit 22 is temporarily assumed to be zero. When the second relay k2 is normally disconnected, the power supply, the filter capacitor C0 and the third impedance unit 21 can form a current loop. When the impedance value of the filter capacitor C0 is much smaller than the impedance value of the fourth impedance unit 22, the voltage division of the third impedance unit 21 is close to the output voltage. Therefore, when the second voltage acquisition unit 23 is connected to the third impedance unit 21, the acquired voltage is close to the output voltage.

[0080] If the first relay k1 is stuck and the second relay k2 is stuck, similarly, if the voltage collected by the first voltage acquisition unit 13 is close to the output voltage, and the voltage collected by the second voltage acquisition unit 23 is very small or close to zero compared with the output voltage, then it can be determined that the first relay k1 is stuck and the second relay k2 is stuck.

[0081] If the first relay k1 and the second relay k2 are normally disconnected, the AC signal will pass through the first detection branch 10 and the second detection branch 20 respectively. Therefore, when the first voltage acquisition unit 13 is connected to the second impedance unit 12, the acquired voltage is the voltage division between the second impedance unit 12 and the first impedance unit 11 and the second impedance unit 12. When the impedance of the first impedance unit 11 is represented by R1, the impedance of the second impedance unit 12 is represented by R2, and the output voltage is represented by Vs, the acquired voltage is close to R2*Vs / (R1+R2). When the second voltage acquisition unit 23 is connected to the third impedance unit 21, the acquired voltage is the voltage division between the third impedance unit 21 and the fourth impedance unit 22. When the impedance of the third impedance unit 21 is represented by R3 and the impedance of the fourth impedance unit 22 is represented by R4, the acquired voltage is close to R3*Vs / (R3+R4).

[0082] Based on this, when power supply m1 outputs an AC signal, and the first relay k1 and the second relay k2 are in different states, the voltages collected by the first voltage acquisition unit 13 and the second voltage acquisition unit 23 are shown in Table 1 below. Wherein, V1 represents the voltage collected when the first voltage acquisition unit 13 is connected to the second impedance unit 12, V2 represents the voltage collected when the second voltage acquisition unit 23 is connected to the third impedance unit 21, and Vs represents the output voltage of power supply m1.

[0083] Table 1

[0084]

[0085] Based on the results given in Table 1 above, when power supply m1 outputs an AC signal, the voltages acquired by the first voltage acquisition unit 13 and the second voltage acquisition unit 23 can be used to determine whether the first relay k1 and the second relay k2 are stuck together. Furthermore, if this determination is referred to as the initial determination, the difference between the voltages acquired by the first voltage acquisition unit 13 and the second voltage acquisition unit 23 (i.e., V1-V2 in Table 1 above) can be calculated. Based on this difference, another determination can be made as to whether the first relay k1 and the second relay k2 are stuck together, or the result of the difference can be used to verify the accuracy of the initial determination, thereby further improving the accuracy of the determination and reducing misjudgments.

[0086] 2. Power supply m1 outputs a DC signal.

[0087] If the first relay k1 is normally disconnected and the second relay k2 is stuck, although the filter capacitor C0 is connected in parallel with the second impedance unit 12, the impedance value of the filter capacitor C0 is much larger than that of the second impedance unit 12. Therefore, the DC signal passes through the first impedance unit 11 and then through the second impedance unit 12 back to the power supply m1. Thus, the voltage collected by the first voltage acquisition unit 13 is the voltage division between the first impedance unit 11 and the second impedance unit 12. When the impedance of the first impedance unit 11 is represented by R1, the impedance of the second impedance unit 12 is represented by R2, and the output voltage is represented by Vs, the collected voltage is close to R2*Vs / (R1+R2). When the second voltage acquisition unit 23 is connected to the third impedance unit 21, the collected voltage is very small or close to zero compared to the output voltage because the second relay k2 is stuck.

[0088] If the first relay k1 is stuck and the second relay k2 is normally disconnected, since the second impedance unit 12 is connected to the second node P2 and the third node P3 respectively, when the potentials of the first node P1 and the second node P2 are the same, the voltage division of the second impedance unit 12 is the voltage between the first node P1 and the third node P3. Since the voltage between the first node P1 and the third node P3 is the output voltage, the voltage division of the second impedance unit 12 is the output voltage. When the first voltage acquisition unit 13 is connected to the second impedance unit 12, the acquired voltage is close to the output voltage. Because the first relay k1 is stuck, the fourth impedance unit 22 and the filter capacitor C0 are connected in parallel. When the impedance value of the filter capacitor C0 is much greater than the impedance value of the fourth impedance unit 22, the current flowing through the filter capacitor C0 is very small and close to zero. Therefore, the fourth impedance unit 22, the third impedance unit 21 and the power supply m1 can form a current loop. When the second voltage acquisition unit 23 is connected to the third impedance unit 21, the acquired voltage is close to the voltage division of the third impedance unit 21 between the third impedance unit 21 and the fourth impedance unit 22. When the impedance of the third impedance unit 21 is represented by R3 and the impedance of the fourth impedance unit 22 is represented by R4, the acquired voltage is close to R3*Vs / (R3+R4).

[0089] If the first relay k1 is stuck and the second relay k2 is stuck, similarly, if the voltage collected by the first voltage acquisition unit 13 is close to the output voltage, and the voltage collected by the second voltage acquisition unit 23 is very small or close to zero compared with the output voltage, then it can be determined that the first relay k1 is stuck and the second relay k2 is stuck.

[0090] If the first relay k1 and the second relay k2 are normally disconnected, similarly, when the first voltage acquisition unit 13 is connected to the second impedance unit 12, the acquired voltage is close to the voltage division of the second impedance unit 12 between the first impedance unit 11 and the second impedance unit 12, i.e., R2*Vs / (R1+R2); when the second voltage acquisition unit 23 is connected to the third impedance unit 21, the acquired voltage is close to the voltage division of the third impedance unit 21 between the third impedance unit 21 and the fourth impedance unit 22, i.e., R3*Vs / (R3+R4).

[0091] Based on this, when the power supply m1 outputs a DC signal, and the first relay k1 and the second relay k2 are in different states, the voltages collected by the first voltage acquisition unit 13 and the second voltage acquisition unit 23 are shown in Table 2 below. Wherein, V1 represents the voltage collected when the first voltage acquisition unit 13 is connected to the second impedance unit 12, V2 represents the voltage collected when the second voltage acquisition unit 23 is connected to the third impedance unit 21, and Vs represents the output voltage of the power supply m1.

[0092] Table 2

[0093]

[0094] Based on the results given in Table 2 above, when power supply m1 outputs a DC signal, the voltages acquired by the first voltage acquisition unit 13 and the second voltage acquisition unit 23 can be used to determine whether the first relay k1 and the second relay k2 are stuck together. Furthermore, if this determination is referred to as the initial determination, the difference between the voltages acquired by the first voltage acquisition unit 13 and the second voltage acquisition unit 23 (i.e., V1-V2 in Table 2 above) can be calculated. Based on this difference, another determination can be made as to whether the first relay k1 and the second relay k2 are stuck together, or the result of the difference can be used to verify the accuracy of the initial determination, thereby further improving the accuracy of the determination and reducing misjudgments.

[0095] Therefore, the detection circuit provided in this application embodiment can be applied not only to AC scenarios but also to DC scenarios. Moreover, especially in scenarios where the input fluctuates frequently, the detection circuit can adjust the potential of the contacts of the two relays to ground to avoid the influence of the Y capacitor, thereby ensuring the normal operation of the two relays.

[0096] In some embodiments, the impedance values ​​of the first, second, third, and fourth impedance units can be set to be the same. In this case, it is sufficient to directly determine whether the voltages acquired by the first and second voltage acquisition units are close to zero, or whether the output voltage is half of the output voltage, thereby simplifying the calculation and improving the judgment efficiency. Of course, the impedance values ​​of the first, second, third, and fourth impedance units can also be set to be at least partially different. This allows the impedance values ​​of each impedance unit to be adjusted according to actual needs to meet the requirements of different application scenarios and improve the design flexibility.

[0097] In some embodiments, when the power supply is used to output an AC signal, at least one of the first impedance unit, the second impedance unit, the third impedance unit, and the fourth impedance unit may include at least one of an inductor, a resistor, and a capacitor; when the power supply is used to output a DC signal, at least one of the first impedance unit, the second impedance unit, the third impedance unit, and the fourth impedance unit may include at least one of a resistor and a capacitor. This allows the structure of each impedance unit to be configured for different application scenarios, thereby improving design flexibility.

[0098] Furthermore, the structures of the first impedance unit, the second impedance unit, the third impedance unit, and the fourth impedance unit can all be set to be the same to simplify the structure of the detection circuit and reduce the manufacturing difficulty and cost of the detection circuit. Of course, the structures of the first impedance unit, the second impedance unit, the third impedance unit, and the fourth impedance unit can also be set to be at least partially different to meet the needs of different application scenarios and improve the flexibility of the design.

[0099] In some embodiments, the output voltage of power supply m1 can be obtained from the power supplier, or a third voltage acquisition unit 30 connected between the two lines can be set up to acquire the output voltage, such as... Figure 2 As shown. Furthermore, the structures of the first voltage acquisition unit 13, the second voltage acquisition unit 23, and the third voltage acquisition unit 30 can all be identical to simplify the detection circuit structure and reduce the manufacturing difficulty and cost. Of course, the structures of the first voltage acquisition unit 13, the second voltage acquisition unit 23, and the third voltage acquisition unit 30 can also be at least partially different to meet the needs of different application scenarios and improve design flexibility. It should be understood that when the third voltage acquisition unit 30 is not provided, the structures of the first voltage acquisition unit 13 and the second voltage acquisition unit 23 can be identical or different.

[0100] In some embodiments, when the first voltage acquisition unit is connected to the first impedance unit, the first impedance unit can be a part of the first voltage acquisition unit, that is, the first impedance unit and the first voltage acquisition unit belong to the same independent device; or, when the first voltage acquisition unit is connected to the second impedance unit, the second impedance unit can be a part of the first voltage acquisition unit, that is, the second impedance unit and the first voltage acquisition unit belong to the same independent device. Similarly, when the second voltage acquisition unit is connected to the third impedance unit, the third impedance unit can be a part of the second voltage acquisition unit, that is, the third impedance unit and the second voltage acquisition unit belong to the same independent device; or, when the second voltage acquisition unit is connected to the fourth impedance unit, the fourth impedance unit can be a part of the second voltage acquisition unit, that is, the fourth impedance unit and the second voltage acquisition unit belong to the same independent device.

[0101] In some embodiments, the specific structures of the first voltage acquisition unit, the second voltage acquisition unit, and the third voltage acquisition unit are not limited herein, and any structure that can realize voltage acquisition is within the protection scope of the embodiments of this application.

[0102] Therefore, when using the above-mentioned detection circuit to detect the sticking condition of the relay, such as Figure 4 As shown, the following processes may be included:

[0103] S401. When the first relay is disconnected and the power supply outputs a signal, and the first detection branch detects at least one of the voltage between the two ends of the first relay and the voltage between the end of the first relay facing the load and the end of the second relay facing the power supply, it is determined whether the first relay has become stuck based on the voltage detected by the first detection branch and the output voltage of the power supply.

[0104] S402, when the second relay is disconnected and the power supply outputs a signal, and at least one of the voltage between the two ends of the second relay and the voltage between the end of the second relay facing the load and the end of the first relay facing the power supply is detected by the second detection branch, it is determined whether the second relay has become stuck based on the voltage detected by the second detection branch and the output voltage.

[0105] Thus, by comparing the voltage detected by the first detection branch with the output voltage, it can be determined whether the first relay is stuck. Similarly, by comparing the voltage detected by the second detection branch with the output voltage, it can be determined whether the second relay is stuck. This allows for the detection of the sticking status of each relay. Furthermore, voltage detection can be performed according to a set acquisition period or triggered at any time as needed. Since voltage detection is not limited by the energizing sequence or interval of the two relays, detection efficiency is improved, thereby enhancing the efficiency of relay judgment.

[0106] In some embodiments, performing S401 as described above may specifically include:

[0107] With the first relay disconnected:

[0108] If a first voltage is detected between the two ends of the first relay (i.e., the voltage between the first node P1 and the second node P2), then... Figure 2 As shown, if the first voltage is not greater than the first preset value, it can be determined that the first relay is stuck; if the first voltage meets the first condition, and the first condition includes: when the power supply is used to output AC signal, the first voltage is located at the output voltage ± the first preset value, or when the power supply is used to output DC signal, the first voltage is located at the voltage division of the first impedance unit in the first impedance unit and the second impedance unit ± the first preset value, it can be determined that the first relay is normally disconnected and is not stuck.

[0109] If a first voltage is detected between the end of the first relay facing the load (i.e., the second node P2) and the end of the second relay facing the power source (the third node P3), such as Figure 3 As shown, if the first voltage is within the range of the output voltage ± the first preset value, it can be determined that the first relay is stuck. If the first voltage meets the second condition, and the second condition includes: when the power supply is used to output an AC signal, the first voltage is not less than the first preset value; when the power supply is used to output a DC signal, the first voltage is within the voltage division of the second impedance unit in the first impedance unit ± the first preset value, it can be determined that the first relay is normally disconnected and is not stuck.

[0110] The first preset value is not less than 0 and not greater than 15% of the output voltage. For example, but not limited to, the first preset value is 0, 5% of the output voltage, 8% of the output voltage, or 10% of the output voltage, etc. Other values ​​are not limited here.

[0111] Thus, based on the above process, it can be determined whether the first relay has become stuck.

[0112] In some embodiments, performing S402 as described above may specifically include:

[0113] When the second relay is disconnected:

[0114] If a second voltage is detected between the two ends of the second relay (i.e., the voltage between the third node P3 and the fourth node P4), such as Figure 3 As shown, if the second voltage is not less than the second preset value, it can be determined that the second relay is stuck; if the second voltage meets the third condition, and the third condition includes: when the power supply is used to output AC signal, the second voltage is located at the output voltage ± the second preset value, or when the power supply is used to output DC signal, the second voltage is located at the voltage division of the third impedance unit between the third impedance unit and the fourth impedance unit ± the second preset value, it can be determined that the second relay is normally disconnected and is not stuck.

[0115] If a second voltage is detected between the end of the second relay facing the load (i.e., the fourth node P4) and the end of the first relay facing the power supply (i.e., the first node P1), such as Figure 2 As shown, if the second voltage is within the range of the output voltage ± the second preset value, it can be determined that the second relay is stuck. If the second voltage meets the fourth condition, and the fourth condition includes: when the power supply is used to output an AC signal, the second voltage is not less than the second preset value, or when the power supply is used to output a DC signal, the second voltage is within the voltage division of the fourth impedance unit between the third impedance unit and the fourth impedance unit ± the second preset value, it can be determined that the second relay is normally disconnected and is not stuck.

[0116] The second preset value is not less than 0 and not greater than 15% of the output voltage. For example, but not limited to, the second preset value is 0, 5% of the output voltage, 8% of the output voltage, or 10% of the output voltage, etc., and is not limited here. Furthermore, the first preset value and the second preset value can be set to be the same or different, depending on the actual situation.

[0117] Thus, based on the above process, it can be determined whether the second relay has become stuck.

[0118] In some embodiments, in addition to directly determining whether each relay is stuck based on the first voltage detected by the first detection branch and the second voltage detected by the second detection branch, the difference between the first voltage and the second voltage can also be calculated, and then based on the difference and the output voltage, it can be determined again whether each relay is stuck, thereby realizing the re-verification of the judgment result and improving the accuracy of the judgment result.

[0119] Based on the above solution, this application also provides a power adapter, such as... Figure 5 and Figure 6As shown, the power adapter m3 may include: a first relay k1, a second relay k2, a detection circuit 100, a converter 300, and a processor 200; of the two lines connected to the converter 300, one line contains the first relay k1, and the other line contains the second relay k2. Furthermore, the two lines connected to the converter 300 can be two lines connecting the converter 300 and the power supply m1, such as... Figure 6 As shown, when the two lines are equipped with a first relay k1 and a second relay k2 respectively, a detection circuit 100 needs to be connected to these two lines; of course, the two lines connected to the converter 300 can also be two lines connecting the converter 300 and the load m2, such as... Figure 5 As shown, when the first relay k1 and the second relay k2 are respectively provided in these two lines, a detection circuit 100 needs to be set up and connected to these two lines; therefore, the detection circuit 100 can be set in the two lines between the converter 300 and the load m2, or it can be set in the two lines between the converter 300 and the power supply m1.

[0120] The detection circuit 100 is connected to both ends of the first relay k1, both ends of the second relay k2, and the processor 200, respectively; for example... Figure 5 As shown, when the detection circuit 100 and the two lines between the converter 300 and the load m2 are connected, since the converter 300 provides electrical energy to the load m2, the converter 300 can be regarded as... Figure 2 and Figure 3 When the power supply in the circuit is open, the detection circuit 100 can be used to detect at least one of the following when both the first relay k1 and the second relay k2 are open and current flows through both lines and the detection circuit 100: the voltage between the two ends of the first relay k1 and the voltage between the end of the first relay k1 away from the converter 300 and the end of the second relay k2 facing the converter 300; and the voltage between the two ends of the second relay k2 and the voltage between the end of the second relay k2 away from the converter 300 and the end of the first relay k1 facing the converter 300.

[0121] like Figure 6 As shown, when the detection circuit 100 is connected to the power supply m1 and the converter 300 via two paths, since the power supply m1 provides power to the converter 300, the converter 300 can be considered as... Figure 2 and Figure 3When the load in the circuit is open, the detection circuit 100 can be used to detect at least one of the following when both the first relay k1 and the second relay k2 are open and current flows through both lines and the detection circuit 100: the voltage between the two ends of the first relay k1 and the voltage between the end of the first relay k1 facing the converter 300 and the end of the second relay k2 away from the converter 300; and the voltage between the two ends of the second relay k2 and the voltage between the end of the second relay k2 facing the converter 300 and the end of the first relay k1 away from the converter 300.

[0122] Furthermore, the detection circuit 100 transmits the detected voltage to the processor 200, which can determine whether the first relay k1 and the second relay k2 are stuck together based on the voltage detected by the detection circuit 100 and the voltage between the two lines.

[0123] In this way, by comparing the voltage detected by the detection circuit with the output voltage between the two lines, it can be determined whether the relays have stuck together. This method of detecting sticking does not require changing the structure of the relays themselves, thus avoiding increasing the manufacturing cost and size of the relays, achieving sticking detection while maintaining the original structure. Furthermore, when detecting voltage, detection can be performed according to a set sampling period, or it can be triggered at any time as needed. Since voltage detection is not limited by the energizing sequence or interval of the two relays, the detection efficiency can be improved, thereby improving the efficiency of relay judgment.

[0124] In some embodiments, the voltage between the two lines can be transmitted to the processor or pre-built into the processor. The processor compares the detected voltage with the voltage between the two lines to determine whether the relays are stuck together, and then outputs the judgment result. When the processor outputs the judgment result, if the processor is connected to a display screen, the judgment result can be displayed on the display screen; if the processor is connected to an alarm, the judgment result can be indicated by different alarm sounds or different colored indicator lights emitted by the alarm. Of course, other methods well known to those skilled in the art can also be used to display the judgment result, and are not limited here.

[0125] The specific implementation principle of the detection circuit in this power adapter is similar to that of the aforementioned detection circuit. For the specific implementation method of the detection circuit in this power adapter, please refer to the specific embodiment of the aforementioned detection circuit. Repeated details will not be repeated.

[0126] In some embodiments, such as Figure 5 and Figure 6As shown, when the power adapter m3 is located between the power source m1 and the load m2, the converter 300 is connected to both the power source m1 and the load m2. In this case, the converter 300 can perform voltage and power conversion processing on the signal output from the power source m1 before transmitting it to the load m2 for use, driving the load m2 to operate. The power source m1 can be an AC source providing AC signals or a DC source providing DC signals. The AC source can be, but is not limited to, an AC power grid or an AC charging station, while the DC source can be, but is not limited to, a photovoltaic power source or a DC charging station. Furthermore, if a first relay k1 and a second relay k2 are respectively installed in the two lines between the converter 300 and the power source m1, such as... Figure 6 As shown, the detection circuit 100 can be connected to the two lines between the converter 300 and the power supply m1, respectively. The voltage between these two lines can then be considered the output voltage of the power supply m1. If a first relay k1 and a second relay k2 are respectively installed in the two lines between the converter 300 and the load m2, as follows... Figure 5 As shown, the detection circuit 100 can be connected to the two lines between the converter 300 and the load m2 respectively. In this case, the voltage between the two lines can be considered as the output voltage of the converter 300.

[0127] In some embodiments, when the detection circuit 100 includes two detection branches, each detection branch can detect voltage. One detection branch is used to detect at least one of the voltage between the first terminal and the second terminal of the first relay k1, and the voltage between the first terminal of the first relay k1 and the second terminal of the second relay k2; the other detection branch is used to detect at least one of the voltage between the first terminal and the second terminal of the second relay k2, and the voltage between the first terminal of the second relay k2 and the second terminal of the first relay k1. At this time, the processor 200 can also calculate the difference between the voltages detected by the two detection branches, and based on the difference and the voltage between the two lines, determine again whether the first relay k1 and the second relay k2 are stuck together. This allows for further determination of whether they are stuck together, improving the accuracy of the determination result.

[0128] In some embodiments, in addition to the structures described above, the power adapter may also include other structures for implementing the functions of the power adapter, such as, but not limited to, output interfaces, rectifier modules, etc., which are not limited here.

[0129] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0130] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A detection circuit for relay sticking, wherein in two lines between the power supply and the load, one of the lines is provided with a first relay and the other line is provided with a second relay; Its features are, The detection circuit includes two detection branches; One of the detection branches includes a first impedance unit and a second impedance unit. The first impedance unit is electrically connected to both ends of the first relay, and the second impedance unit is electrically connected to the end of the first relay facing the load and the end of the second relay facing the power source, respectively. The other detection branch includes a third impedance unit and a fourth impedance unit. The third impedance unit is electrically connected to both ends of the second relay, and the fourth impedance unit is electrically connected to the end of the first relay facing the power source and the end of the second relay facing the load, respectively. Each of the aforementioned detection branches is used for: When both the first relay and the second relay are disconnected and the power supply outputs a signal, at least one of the following is detected: the voltage between the two ends of the corresponding relay and the voltage between one end of the first relay and the other end of the second relay. Based on the detected voltage and the output voltage of the power supply, it is determined whether the corresponding relay has become stuck. One end of the first relay and the other end of the second relay face the power supply, and the other faces the load.

2. The detection circuit as described in claim 1, characterized in that, The detection branch connected to both ends of the first relay is specifically used for: The voltage between the two ends of the first relay and at least one of the voltages between the end of the first relay facing the load and the end of the second relay facing the power source are detected to determine whether the first relay is stuck based on the detected voltage and the output voltage.

3. The detection circuit as described in claim 1 or 2, characterized in that, The detection branch connected to both ends of the first relay further includes a first voltage acquisition unit; At least one of the first impedance unit and the second impedance unit is electrically connected to the first voltage acquisition unit. The first voltage acquisition unit is used to acquire at least one of the voltage between the two ends of the first relay and the voltage between the end of the first relay facing the load and the end of the second relay facing the power source.

4. The detection circuit as described in claim 1, characterized in that, The detection branch connected to both ends of the second relay is specifically used for: The voltage between the two ends of the second relay and at least one of the voltages between the end of the second relay facing the load and the end of the first relay facing the power source are detected to determine whether the second relay is stuck based on the detected voltages and the output voltage.

5. The detection circuit as described in any one of claims 1-4, characterized in that, The detection branch connected to both ends of the second relay also includes a second voltage acquisition unit; At least one of the third impedance unit and the fourth impedance unit is electrically connected to the second voltage acquisition unit, which is used to acquire at least one of the voltage between the two ends of the second relay and the voltage between the end of the second relay facing the load and the end of the first relay facing the power source.

6. The detection circuit as described in claim 5, characterized in that, The power supply is used to output AC signals, and at least one of the first impedance unit, the second impedance unit, the third impedance unit, and the fourth impedance unit includes at least one of inductor, resistor, and capacitor.

7. The detection circuit as described in claim 5, characterized in that, The power supply is used to output a DC signal, and at least one of the first impedance unit, the second impedance unit, the third impedance unit, and the fourth impedance unit includes at least one of a resistor and a capacitor.

8. A power adapter, characterized in that, include: First relay, second relay, detection circuit, converter, and processor; Of the two lines connected to the converter, one line is equipped with the first relay, and the other line is equipped with the second relay; The detection circuit includes: a first impedance unit, a second impedance unit, a third impedance unit, and a fourth impedance unit. The first impedance unit is electrically connected to a first terminal and a second terminal of the first relay, respectively. The second impedance unit is electrically connected to a first terminal and a second terminal of the first relay, respectively. The third impedance unit is electrically connected to a first terminal and a second terminal of the second relay, respectively. The fourth impedance unit is electrically connected to a first terminal of the second relay and a second terminal of the first relay, respectively. The detection circuit is used to detect at least one of the voltage between the first terminal of the first relay and the second terminal of the first relay, and the voltage between the first terminal of the first relay and the second terminal of the second relay, when both the first relay and the second relay are disconnected and current flows through the two lines and the detection circuit. Detect at least one of the voltage between the first terminal of the second relay and the second terminal of the second relay, and the voltage between the first terminal of the second relay and the second terminal of the first relay; the first terminal of the first relay and the first terminal of the second relay are both located on the side facing the converter or both are located on the side away from the converter; The processor is connected to the detection circuit, and the processor is used to: determine whether the first relay and the second relay are stuck together based on the voltage detected by the detection circuit and the voltage between the two lines.

9. The power adapter as described in claim 8, characterized in that, The detection circuit includes two detection branches, one of which is used to detect at least one of the voltage between the first terminal and the second terminal of the first relay and the voltage between the first terminal and the second terminal of the second relay; the other detection branch is used to detect at least one of the voltage between the first terminal and the second terminal of the second relay and the voltage between the first terminal and the second terminal of the second relay. The processor is further configured to: calculate the difference between the voltage detected by one of the detection branches and the voltage detected by the other detection branch, and based on the difference and the voltage between the two lines, determine again whether the two relays are stuck together.

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