Relay sticking detection circuit and detection method

Abstract

The embodiment of the application relates to a relay sticking detection circuit and a detection method, the circuit comprising: an alternating current power supply group, a leakage current sensor, a relay group, a voltage sampling module and a current sampling module; the output end of the alternating current power supply group is connected to the input end of the leakage current sensor; the output end of the leakage current sensor is connected to the input end of the relay group; the first output end of the relay group is connected to the input end of the voltage sampling module, and the second output end is connected to the input end of the current sampling module. Voltage and current are collected by the voltage sampling module and the current sampling module as reference data for judging relay sticking, so that relay sticking detection is realized, and input power is obtained based on the voltage and the current. Therefore, relay sticking can be detected while input power is monitored, so that the technical effect of reducing a voltage detection circuit and saving circuit resources is achieved.

Description

Technical Field

[0001] This application relates to the technical field of adhesion detection, and in particular to a relay adhesion detection circuit and detection method. Background Technology

[0002] Electromagnetic relays mainly consist of an iron core, a coil, and an armature with contacts. For normally open relays, when closing the relay, a working voltage is applied across the coil, causing a current to flow through it and generating an electromagnetic effect. This causes the moving contact on the armature to contact the fixed stationary contact, achieving the closing operation. When opening the relay, simply setting the working voltage across the coil to zero allows the armature to reset under spring force after losing electromagnetic force, thus separating the moving and stationary contacts. However, power conversion systems (PCS) experience overvoltage and overcurrent during power outages, leading to transient arcing and contact adhesion at the contacts. Studies show that relay adhesion can occur during the power-on or power-off process of a PCS. To ensure user power safety and the normal operation of the PCS, a relay adhesion detection circuit must be added.

[0003] Existing relay sticking detection circuits reduce the possibility of simultaneous sticking by using two pre-charged relays connected in series for pre-charging. However, this method uses a large number of relays and requires multiple voltage detection points. Another method is to determine the bus cluster in the multi-cluster battery system by analyzing the operating status of the multi-cluster battery system. The sticking status of the relays in the bus cluster can be detected by the voltage difference between the front and rear ends of the relays or the loop current value. However, this method requires identifying the bus cluster and using multiple current sensors. Summary of the Invention

[0004] In view of this, in order to solve the above-mentioned technical problem of relay adhesion, this application provides a relay adhesion detection circuit and detection method.

[0005] In a first aspect, embodiments of this application provide a relay adhesion detection circuit, including: AC power supply unit, leakage current sensor, relay group, voltage sampling module and current sampling module; The output terminal of the AC power supply is connected to the input terminal of the leakage current sensor; The output terminal of the leakage current sensor is connected to the input terminal of the relay group; The first output terminal of the relay group is connected to the input terminal of the voltage sampling module, and the second output terminal is connected to the input terminal of the current sampling module.

[0006] In one possible implementation, the AC power supply group includes: a first AC power supply, a second AC power supply, and a third AC power supply; The output terminal of the first AC power supply is connected to the first input terminal of the leakage current sensor; The output terminal of the second AC power supply is connected to the second input terminal of the leakage current sensor; The output terminal of the third AC power supply is connected to the third input terminal of the leakage current sensor.

[0007] In one possible implementation, the relay group includes: a first relay unit, a second relay unit, and a third relay unit; The input terminal of the first relay unit is connected to the first output terminal of the leakage current sensor, the first output terminal is connected to the first input terminal of the voltage sampling module, and the second output terminal is connected to the first input terminal of the current sampling module. The input terminal of the second relay unit is connected to the second output terminal of the leakage current sensor, the first output terminal is connected to the second input terminal of the voltage sampling module, and the second output terminal is connected to the second input terminal of the current sampling module. The input terminal of the third relay unit is connected to the third output terminal of the leakage current sensor, the first output terminal is connected to the third input terminal of the voltage sampling module, and the second output terminal is connected to the third input terminal of the current sampling module.

[0008] In one possible implementation, the voltage sampling module includes: a first voltage sampling unit, a second voltage sampling unit, and a third voltage sampling unit; The first input terminal of the first voltage sampling unit is connected to the first output terminal of the first relay unit, and the second input terminal is connected to the first output terminal of the second relay unit. The first input terminal of the second voltage sampling unit is connected to the first output terminal of the second relay unit, and the second input terminal is connected to the first output terminal of the third relay unit; The first input terminal of the third voltage sampling unit is connected to the first output terminal of the third relay unit, and the second input terminal is connected to the first output terminal of the first relay unit. The current sampling module includes: a first current sampling unit, a second current sampling unit, and a third current sampling unit; The input terminal of the first current sampling unit is connected to the second output terminal of the first relay unit; The input terminal of the second current sampling unit is connected to the second output terminal of the second relay unit; The input terminal of the third current sampling unit is connected to the second output terminal of the third relay unit.

[0009] In one possible implementation, the first relay unit includes a first relay, a second relay, a third relay, a first resistor, and a second resistor; One end of the first relay is connected to the first output terminal of the leakage current sensor, and the other end is connected to the first node via one end of the first resistor, one end of the second relay, the first input terminal of the first voltage sampling unit, and the first input terminal of the third voltage sampling unit. The other end of the second relay is connected to the other end of the third relay and the input terminal of the first current sampling unit to the second node; The other end of the first resistor is connected to one end of the second resistor; The other end of the second resistor is connected to one end of the third relay; The second relay unit includes a fourth relay, a fifth relay, a sixth relay, a third resistor, and a fourth resistor; One end of the fourth relay is connected to the second output terminal of the leakage current sensor, and the other end is connected to the third node via one end of the third resistor, one end of the fifth relay, the second input terminal of the first voltage sampling unit, and the first input terminal of the second voltage sampling unit. The other end of the fifth relay is connected to the other end of the sixth relay and the input terminal of the second current sampling unit to the fourth node; The other end of the third resistor is connected to one end of the fourth resistor; The other end of the fourth resistor is connected to one end of the sixth relay; The third relay unit includes a seventh relay, an eighth relay, a ninth relay, a fifth resistor, and a sixth resistor; One end of the seventh relay is connected to the third output terminal of the leakage current sensor, and the other end is connected to the fifth node via one end of the fifth resistor, one end of the eighth relay, the second input terminal of the second voltage sampling unit, and the second input terminal of the third voltage sampling unit. The other end of the eighth relay is connected to the sixth node along with the other end of the ninth relay and the input terminal of the third current sampling unit; The other end of the fifth resistor is connected to one end of the sixth resistor; The other end of the sixth resistor is connected to one end of the ninth relay; The switching states of the first, fourth, and seventh relays are controlled by a first switching signal; the switching states of the second, fifth, and eighth relays are controlled by a second switching signal; and the switching states of the third, sixth, and ninth relays are controlled by a third switching signal.

[0010] In one possible implementation, the first voltage sampling unit, the second voltage sampling unit, and the third voltage sampling unit have the same internal structure; The first voltage sampling unit includes: a first resistor subunit, a second resistor subunit, a first filter subunit, a second filter subunit, a third filter subunit, and a first amplifier. The first resistor subunit and the second resistor subunit are each composed of multiple resistors connected in series. One end of the first resistor subunit is connected to the first output terminal of the first relay unit, and the other end is connected to the negative input terminal of the first amplifier and the input terminal of the first filter subunit. The output terminal of the first filtering subunit is connected to the output terminal of the first amplifier and the input terminal of the third filtering subunit; One end of the second resistor subunit is connected to the first output terminal of the second relay unit, and the other end is connected to the positive input terminal of the first amplifier and the input terminal of the second filter subunit; The output terminal of the second filter subunit is connected to the first ground terminal; The first output terminal of the third filter subunit is connected to the first voltage control signal terminal, and the second output terminal is connected to the second ground terminal.

[0011] In one possible implementation, the first current sampling unit, the second current sampling unit, and the third current sampling unit are each composed of the same internal structure; The first current sampling unit includes: a first current sensor and a first operational amplifier subunit; The non-inverting input terminal of the first current sensor is connected to the second output terminal of the first relay unit, the inverting input terminal is connected to the second output terminal of the first relay unit, and the output terminal is connected to the input terminal of the first operational amplifier subunit. The output terminal of the first operational amplifier subunit is connected to the first current control signal terminal; The second current sampling unit includes: a second current sensor and a second operational amplifier subunit; The non-inverting input terminal of the second current sensor is connected to the second output terminal of the second relay unit, the inverting input terminal is connected to the second output terminal of the second relay unit, and the output terminal is connected to the input terminal of the second operational amplifier subunit. The output of the second operational amplifier subunit is connected to the second current control signal terminal; The third current sampling unit includes: a third current sensor and a third operational amplifier subunit; The positive input terminal of the third current sensor is connected to the second output terminal of the third relay unit, the negative input terminal is connected to the second output terminal of the third relay unit, and the output terminal is connected to the input terminal of the third operational amplifier subunit. The output terminal of the third operational amplifier subunit is connected to the third current control signal terminal.

[0012] In one possible implementation, the circuit further includes: a first fuse, a second fuse, a third fuse, a first anti-interference module, a second anti-interference module, a third anti-interference module, a first varistor, a second varistor, a third varistor, a first discharge tube, a second discharge tube, and a third discharge tube; One end of the first fuse is connected to the first output terminal of the AC power supply, and the other end is connected to one end of the first anti-interference module, one end of the first varistor, and the first input terminal of the leakage current sensor. The other end of the first anti-interference module is connected to the third grounding terminal; The other end of the first varistor is connected to one end of the first discharge tube; The other end of the first discharge tube is connected to the fourth grounding terminal; One end of the second fuse is connected to the second output terminal of the AC power supply, and the other end is connected to one end of the second anti-interference module, one end of the second varistor, and the second input terminal of the leakage current sensor. The other end of the second anti-interference module is connected to the third grounding terminal; The other end of the second varistor is connected to one end of the second discharge tube; The other end of the second discharge tube is connected to the fifth grounding terminal; One end of the third fuse is connected to the third output terminal of the AC power supply, and the other end is connected to one end of the third anti-interference module, one end of the third varistor, and the third input terminal of the leakage current sensor. The other end of the third anti-interference module is connected to the third grounding terminal; The other end of the third varistor is connected to one end of the third discharge tube; The other end of the third discharge tube is connected to the sixth grounding terminal.

[0013] In a second aspect, embodiments of this application provide a relay adhesion detection method, applied to any of the relay adhesion detection circuits described in the first aspect, comprising: Determine the switching status of the relay group in the detection circuit based on the operating status of the target converter; Multiple sampled voltages are obtained using the voltage sampling module, and multiple sampled currents are obtained using the current sampling module. Determine whether all the sampled voltages meet the first preset condition and whether the sampled current simultaneously meets the second preset condition, and obtain the corresponding determination result; The relay adhesion result in the detection circuit is determined based on the judgment result.

[0014] In one possible implementation, determining the switching state of the relay group in the detection circuit based on the operating state of the target converter includes: When the target converter is in a de-energized state, it is determined that the first relay, the second relay, the fourth relay, the fifth relay, the seventh relay, and the eighth relay are in a closed state, and the third relay, the sixth relay, and the ninth relay are in an open state. When the target converter is powered on, it is determined that all relays in the relay group are in the off state.

[0015] In one possible implementation, obtaining multiple corresponding sampled voltages through the voltage sampling module and obtaining multiple corresponding sampled currents through the current sampling module includes: For any voltage sampling unit in the voltage sampling module, the first sampling voltage, the second sampling voltage, and the third sampling voltage are obtained through voltage sampling processing. For any current sampling unit in the current sampling module, the first sampling current, the second sampling current, and the third sampling current are obtained through current sampling processing.

[0016] In one possible implementation, determining whether all the sampled voltages satisfy a first preset condition and whether all the sampled currents simultaneously satisfy a second preset condition, and obtaining the corresponding determination result, includes: When the target converter is in a power-off state, the first switch signal is low and the second switch signal is high, it is determined whether the first sampled voltage, the second sampled voltage and the third sampled voltage satisfy the first relationship, and at the same time whether the first sampled current, the second sampled current and the third sampled current satisfy the second relationship, and the corresponding first judgment result is obtained. The first judgment result indicates that the first relay, the fourth relay or the seventh relay is stuck together. When the target converter is in a de-energized state and both the first and second switching signals are at a low level, it is determined whether the first sampling voltage, the second sampling voltage, and the third sampling voltage satisfy the third relationship, and at the same time, it is determined whether the first sampling current, the second sampling current, and the third sampling current satisfy the fourth relationship, and the corresponding second judgment result is obtained. The second judgment result indicates the state of adhesion of the second relay, the fifth relay, or the eighth relay.

[0017] In one possible implementation, determining the relay adhesion result in the detection circuit based on the judgment result includes: When the judgment result is the first judgment result, it is determined that there is relay sticking among the first relay, the fourth relay, and the seventh relay; The first number of relays stuck together is determined based on the second relationship; The adhesion results of the first relay, the fourth relay, and the seventh relay are determined based on the relationship between the first adhesion quantity and the first sampling current, the second sampling current, and the third sampling current. When the judgment result is the second judgment result, it is determined that there is relay sticking among the second relay, the fifth relay, and the eighth relay; The second adhesion quantity of the relay is determined according to the fourth relationship; The adhesion results of the second, fifth, and eighth relays are determined based on the relationship between the second adhesion quantity and the first, second, and third sampling currents.

[0018] In one possible implementation, determining whether all the sampled voltages satisfy a first preset condition and whether all the sampled currents simultaneously satisfy a second preset condition, and obtaining the corresponding determination result, includes: When the target converter is powered on, the first switch signal is high, and the second and third switch signals are both low, it is determined whether the first sampled voltage, the second sampled voltage, and the third sampled voltage satisfy the fifth relationship, and at the same time, whether the first sampled current, the second sampled current, and the third sampled current satisfy the sixth relationship, and the corresponding third judgment result is obtained. The third judgment result represents the state of adhesion of the third relay, the sixth relay, or the ninth relay caused by the last power failure of the detection circuit. When the target converter is powered on, the first switch signal is high, and the second switch signal and the third switch signal are both low, it is determined whether the first sampled voltage, the second sampled voltage and the third sampled voltage satisfy the seventh relationship, and at the same time whether the first sampled current, the second sampled current and the third sampled current satisfy the eighth relationship, and the corresponding fourth judgment result is obtained. The fourth judgment result indicates the state of sticking of the first relay, the fourth relay or the seventh relay when powered on. When the target converter is powered on, the first switch signal and the third switch signal are both at high level, and the second switch signal is at low level, it is determined whether the first sampled voltage, the second sampled voltage and the third sampled voltage satisfy the ninth relationship, and at the same time whether the first sampled current, the second sampled current and the third sampled current satisfy the tenth relationship, and the corresponding fifth judgment result is obtained. The fifth judgment result indicates the state of adhesion of the third relay, the sixth relay or the ninth relay when powered on. When the target converter is powered on, the first switch signal and the second switch signal are both at a high level, and the third switch signal is at a low level, it is determined whether the first sampled voltage, the second sampled voltage and the third sampled voltage satisfy the eleventh relationship, and at the same time whether the first sampled current, the second sampled current and the third sampled current satisfy the twelfth relationship, to obtain the corresponding sixth judgment result. The sixth judgment result indicates the state of adhesion of the second relay, the fifth relay or the eighth relay when powered on.

[0019] In one possible implementation, determining the relay adhesion result based on the judgment result includes: When the judgment result is the third judgment result, it is determined that there was relay sticking in the third, sixth and ninth relays when the target converter was last powered off. The third adhesion quantity of the relay is determined based on the sixth relationship; The adhesion results of the third relay, the sixth relay, and the ninth relay are determined based on the relationship between the third adhesion quantity and the first sampling current, the second sampling current, and the third sampling current; When the judgment result is the fourth judgment result, it is determined that there is relay sticking among the first relay, fourth relay and seventh relay when the target converter is powered on; The fourth adhesion quantity of the relay is determined based on the seventh relationship; The adhesion results of the first relay, the fourth relay, and the seventh relay are determined based on the relationship between the fourth adhesion quantity and the first, second, and third sampling voltages. When the judgment result is the fifth judgment result, it is determined that there is relay sticking in the third, sixth and ninth relays when the target converter is powered on; The fifth adhesion quantity of the relay is determined based on the tenth relationship described above; The adhesion results of the third relay, the sixth relay, and the ninth relay are determined based on the relationship between the fifth adhesion quantity and the first sampling current, the second sampling current, and the third sampling current; When the judgment result is the sixth judgment result, it is determined that there is relay sticking in the second, fifth and eighth relays when the target converter is powered on; The sixth adhesion quantity of the relay is determined based on the twelfth relationship described above; The adhesion results of the second relay, the fifth relay, and the eighth relay are determined based on the relationship between the sixth adhesion quantity and the first sampling current, the second sampling current, and the third sampling current.

[0020] The relay sticking detection circuit provided in this application embodiment comprises an AC power supply group, a leakage current sensor, a relay group, a voltage sampling module, and a current sampling module. The output terminal of the AC power supply group is connected to the input terminal of the leakage current sensor; the output terminal of the leakage current sensor is connected to the input terminal of the relay group; the first output terminal of the relay group is connected to the input terminal of the voltage sampling module, and the second output terminal is connected to the input terminal of the current sampling module. Different voltages and currents are collected using the voltage and current sampling modules. Multiple voltages and currents are used together to define reference data for judging relay sticking, determining the relay sticking detection result, and realizing relay sticking detection. Simultaneously, the input power is obtained based on the voltage and current. This solution can simultaneously detect relay sticking and monitor input power, achieving the technical effect of reducing voltage detection circuitry and saving circuit resources. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0024] Figure 1 This is a schematic diagram of the structure of a relay adhesion detection circuit provided in an embodiment of this application; Figure 2 This is a schematic diagram of another relay adhesion detection circuit provided in an embodiment of this application; Figure 3 A schematic diagram of another relay adhesion detection circuit provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the first voltage sampling unit provided in an embodiment of this application; Figure 5 This is a schematic diagram of the structure of the first current sampling unit provided in an embodiment of this application; Figure 6 A schematic flowchart of a detection method provided in an embodiment of this application; Figure 7 A flowchart illustrating another detection method provided in an embodiment of this application; Figure 8 This is a flowchart illustrating another detection method provided in an embodiment of this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] The terms "comprising" and "having" in the embodiments of this application are used to indicate an open-ended inclusion, meaning that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms "first" and "second," etc., are used only as labels and are not intended to limit the number of objects. Furthermore, the different elements and areas in the drawings are only schematic, therefore this application is not limited to the dimensions or distances shown in the drawings.

[0027] To facilitate understanding of the embodiments of this application, the following will provide further explanation and description with reference to the accompanying drawings and specific embodiments. These embodiments do not constitute a limitation on the embodiments of this application.

[0028] Figure 1 This is a schematic diagram of a relay adhesion detection circuit provided in an embodiment of this application. It is applied to the relay adhesion detection process. According to... Figure 1 The provided diagram shows that the relay adhesion detection circuit specifically includes: AC power supply group 11, leakage current sensor 12, relay group 13, voltage sampling module 14 and current sampling module 15.

[0029] The output terminal of AC power supply 11 is connected to the input terminal of leakage current sensor 12.

[0030] The output terminal of the leakage current sensor 12 is connected to the input terminal of the relay group 13.

[0031] The first output terminal of the relay group 13 is connected to the input terminal of the voltage sampling module 14, and the second output terminal is connected to the input terminal of the current sampling module 15.

[0032] The AC power supply group 11 provides AC signals to the circuit. The leakage current sensor detects whether leakage current exists in the AC output signal. The relay group controls the delivery of different AC signals to the connected circuits, acting as a switching control. The voltage sampling module samples the voltage output after passing through the relay group. The current sampling module samples the current output by the relay group, serving as reference data for relay sticking detection.

[0033] according to Figure 1 The provided diagram shows that the voltage output of the relay group is collected by the voltage sampling module, and the current output of the relay group is collected by the current sampling module. The magnitude of the detected current and voltage is used as reference data to determine whether the relay has stuck together, thus achieving the purpose of relay sticking detection. The input power of the PCS converter is obtained by multiplying the current and voltage, thereby achieving the purpose of monitoring the magnitude of the reference input power and thus identifying relay sticking. At the same time, it can detect AC power, achieve the technical effect of real-time viewing of AC power, and save controller resources.

[0034] Figure 2 This is a schematic diagram of another relay adhesion detection circuit provided in an embodiment of this application. Figure 2 This is based on the previous embodiment. (See reference) Figure 2 The provided diagram shows that the relay adhesion detection circuit specifically includes: AC power supply group 11, leakage current sensor 12, relay group 13, voltage sampling module 14 and current sampling module 15.

[0035] according to Figure 2 The provided diagram shows that the AC power supply group 11 in the relay adhesion detection circuit includes: a first AC power supply A, a second AC power supply B, and a third AC power supply C.

[0036] The output terminal of the first AC power supply A is connected to the first input terminal of the leakage current sensor 12.

[0037] The output terminal of the second AC power supply B is connected to the second input terminal of the leakage current sensor 12.

[0038] The output terminal of the third AC power supply C is connected to the third input terminal of the leakage current sensor 12.

[0039] The AC power supply is divided into three phases, and the first AC power supply phase A, the second AC power supply phase B, and the third AC power supply phase C are respectively connected to the leakage current sensor 12.

[0040] according to Figure 2 The provided diagram shows that the relay group 13 in the relay adhesion detection circuit includes: a first relay unit 131, a second relay unit 132, and a third relay unit 133.

[0041] The input terminal of the first relay unit 131 is connected to the first output terminal of the leakage current sensor 12, the first output terminal is connected to the first input terminal of the voltage sampling module 14, and the second output terminal is connected to the first input terminal of the current sampling module 15.

[0042] The input terminal of the second relay unit 132 is connected to the second output terminal of the leakage current sensor 12, the first output terminal is connected to the second input terminal of the voltage sampling module 14, and the second output terminal is connected to the second input terminal of the current sampling module 15.

[0043] The input terminal of the third relay unit 133 is connected to the third output terminal of the leakage current sensor 12, the first output terminal is connected to the third input terminal of the voltage sampling module 14, and the second output terminal is connected to the third input terminal of the current sampling module 15.

[0044] The relay group is divided into three units according to the three-phase electrical structure, with each relay unit having the same mechanism. A voltage sampling module collects the gap voltage of each of the three relay units, obtaining three sampled voltages. A current sampling module samples the current of each relay unit, obtaining three corresponding sampled currents. By analyzing the magnitudes of the sampled voltages and currents, it is determined whether the relays have reached the sticking condition, thus obtaining the monitoring results. Simultaneously, the input power is obtained using the sampled voltages and currents, achieving the purpose of monitoring power while detecting relay sticking.

[0045] according to Figure 2 The provided diagram shows that the voltage sampling module 14 in the relay adhesion detection circuit includes: a first voltage sampling unit 141, a second voltage sampling unit 142, and a third voltage sampling unit 143.

[0046] The first input terminal of the first voltage sampling unit 141 is connected to the first output terminal of the first relay unit 131, and the second input terminal is connected to the first output terminal of the second relay unit 132.

[0047] The first input terminal of the second voltage sampling unit 142 is connected to the first output terminal of the second relay unit 132, and the second input terminal is connected to the first output terminal of the third relay unit 133.

[0048] The first input terminal of the third voltage sampling unit 143 is connected to the first output terminal of the third relay unit 133, and the second input terminal is connected to the first output terminal of the first relay unit 131.

[0049] The current sampling module 15 includes: a first current sampling unit 151, a second current sampling unit 152 and a third current sampling unit 153.

[0050] The input terminal of the first current sampling unit 151 is connected to the second output terminal of the first relay unit 131.

[0051] The input terminal of the second current sampling unit 152 is connected to the second output terminal of the second relay unit 132.

[0052] The input terminal of the third current sampling unit 153 is connected to the second output terminal of the third relay unit 133.

[0053] The current sampling module is divided into three identical units based on the three-phase electrical structure. Each current sampling unit samples the three-phase current, and the magnitude of the current is analyzed to determine if the relay has stuck.

[0054] Figure 3 This is a schematic diagram of another relay adhesion detection circuit provided in an embodiment of this application. Figure 3This is based on the first embodiment. Figure 3 The provided diagram shows that the first relay unit 131 in the relay adhesion monitoring circuit includes: a first relay K1, a second relay K2, a third relay K3, a first resistor R1, and a second resistor R2.

[0055] One end of the first relay K1 is connected to the first output terminal of the leakage current sensor 12, and the other end is connected to the first node (hereinafter collectively referred to as P1) via one end of the first resistor R1, one end of the second relay K2, the first input terminal of the first voltage sampling unit 141, and the first input terminal of the third voltage sampling unit 143.

[0056] The other end of the second relay K2, the other end of the third relay K3, and the input terminal of the first current sampling unit 151 are connected to the second node (hereinafter collectively referred to as P2).

[0057] The other end of the first resistor R1 is connected to one end of the second resistor R2.

[0058] The other end of the second resistor R2 is connected to one end of the third relay K3.

[0059] The second relay unit 132 includes: a fourth relay K4, a fifth relay K5, a sixth relay K6, a third resistor R3, and a fourth resistor R4.

[0060] One end of the fourth relay K4 is connected to the second output terminal of the leakage current sensor 12, and the other end is connected to one end of the third resistor R3, one end of the fifth relay K5, the second input terminal of the first voltage sampling unit 141, and the first input terminal of the second voltage sampling unit 142 to the third node (hereinafter collectively referred to as P3).

[0061] The other end of the fifth relay K5, the other end of the sixth relay K6, and the input terminal of the second current sampling unit 152 are connected to the fourth node (hereinafter collectively referred to as P4).

[0062] The other end of the third resistor R3 is connected to one end of the fourth resistor R4.

[0063] The other end of the fourth resistor R4 is connected to one end of the sixth relay K6.

[0064] The third relay unit 133 includes: a seventh relay K7, an eighth relay K8, a ninth relay K9, a fifth resistor R5, and a sixth resistor R6.

[0065] One end of the seventh relay K7 is connected to the third output terminal of the leakage current sensor 12, and the other end is connected to the fifth node (hereinafter collectively referred to as P5) via one end of the fifth resistor R5, one end of the eighth relay K8, the second input terminal of the second voltage sampling unit 142, and the second input terminal of the third voltage sampling unit 143.

[0066] The other end of the eighth relay K8, the other end of the ninth relay K9, and the input terminal of the third current sampling unit 153 are connected to the sixth node (hereinafter collectively referred to as P6).

[0067] The other end of the fifth resistor R5 is connected to one end of the sixth resistor R6.

[0068] The other end of the sixth resistor R6 is connected to one end of the ninth relay K9.

[0069] The switching states of the first relay K1, the fourth relay K4, and the seventh relay K7 are controlled by the first switching signal RLY1_24V; the switching states of the second relay K2, the fifth relay K5, and the eighth relay K8 are controlled by the second switching signal RLY2_24V; and the switching states of the third relay K3, the sixth relay K6, and the ninth relay K9 are controlled by the third switching signal RLY3_24V.

[0070] according to Figure 3 The diagram illustrates how a three-phase power supply, after being processed by a leakage current sensor 12, outputs electrical signals through a first relay unit, a second relay unit, and a third relay unit. Voltage signals are acquired by using the first node P1, the third node P3, and the fifth node P5 as input terminals of a voltage sampling module. The three-phase currents are acquired through the second node P2, the fourth node P4, and the sixth node P6 to obtain sampled current signals. The acquired voltage and current are used as data to determine if the relays are stuck, thus achieving the purpose of relay sticking monitoring. This method can also be used to monitor power.

[0071] according to Figure 3 The provided diagram shows that the relay adhesion monitoring circuit also includes: a first fuse Q1, a second fuse Q2, a third fuse Q3, a first anti-interference module 31, a second anti-interference module 32, a third anti-interference module 33, a first varistor Z1, a second varistor Z2, a third varistor Z3, a first discharge tube U1, a second discharge tube U2, and a third discharge tube U3.

[0072] One end of the first fuse Q1 is connected to the first output terminal of the AC power supply group 11, and the other end is connected to one end of the first anti-interference module 31, one end of the first varistor Z1, and the first input terminal of the leakage current sensor 12.

[0073] The other end of the first anti-interference module 31 is connected to the third grounding terminal.

[0074] The other end of the first varistor Z1 is connected to one end of the first discharge tube U1.

[0075] The other end of the first discharge tube U1 is connected to the fourth grounding terminal.

[0076] One end of the second fuse Q2 is connected to the second output terminal of the AC power supply group 11, and the other end is connected to one end of the second anti-interference module 32, one end of the second varistor Z2, and the second input terminal of the leakage current sensor 12.

[0077] The other end of the second anti-interference module 32 is connected to the third grounding terminal.

[0078] The other end of the second varistor Z2 is connected to one end of the second discharge tube U2.

[0079] The other end of the second discharge tube U2 is connected to the fifth grounding terminal.

[0080] One end of the third fuse Q3 is connected to the third output terminal of the AC power supply group 11, and the other end is connected to one end of the third anti-interference module 33, one end of the third varistor Z3, and the third input terminal of the leakage current sensor 12.

[0081] The other end of the third anti-interference module 33 is connected to the third grounding terminal.

[0082] The other end of the third varistor Z3 is connected to one end of the third discharge tube U3.

[0083] The other end of the third discharge tube U3 is connected to the sixth grounding terminal.

[0084] In the relay adhesion monitoring circuit, the first relay K1, the fourth relay K4, and the seventh relay K4 in relay group 13 are used as the first group of main relays, the second relay K2, the fifth relay K5, and the eighth relay K8 are used as the second group of relays, and the third relay K3, the sixth relay K6, and the ninth relay K9 are used as auxiliary relays.

[0085] When the PCS energy storage converter is powered on, the DC bus capacitor charges, resulting in a relatively large current. At this time, the charging circuit's first resistor R1 to sixth resistor R6 and the auxiliary relay effectively suppress overcurrent. The relay contacts would heat up and stick together under high current; suppressing overcurrent effectively prevents relay sticking. Simultaneously, the PCS energy storage converter may also generate overcurrent during a fault. In this case, the three fuses in the circuit will blow under high current, protecting the circuit while reducing the likelihood of relay sticking.

[0086] Overvoltages may occur during lightning strikes or internal faults in the PCS energy storage converter. Adding a varistor and discharge tube provides protection during these events, preventing overvoltage damage to the relays, reducing their lifespan, and minimizing relay sticking. Simultaneously, using a 3V / 3A meter, input power can be monitored in real time. This achieves both relay sticking monitoring and input power monitoring simultaneously.

[0087] Figure 4 This is a schematic diagram of the structure of the first voltage sampling unit provided in an embodiment of this application. Figure 4 The provided diagram shows that the first voltage sampling unit 141, the second voltage sampling unit 142, and the third voltage sampling unit 143 in the relay adhesion monitoring circuit have the same internal structure.

[0088] The first voltage sampling unit 141 includes: a first resistor subunit 41, a second resistor subunit 42, a first filter subunit 43, a second filter subunit 44, a third filter subunit 45, and a first amplifier A1. The first resistor subunit 41 and the second resistor subunit 42 are each composed of multiple resistors connected in series.

[0089] One end of the first resistor subunit 41 is connected to the first output terminal of the first relay unit 131, and the other end is connected to the negative input terminal of the first amplifier A1 and the input terminal of the first filter subunit 43.

[0090] The output of the first filter subunit 43 is connected to the output of the first amplifier A1 and the input of the third filter subunit 45.

[0091] One end of the second resistor subunit 42 is connected to the first output terminal of the second relay unit 132, and the other end is connected to the positive input terminal of the first amplifier A1 and the input terminal of the second filter subunit 44.

[0092] The output of the second filter subunit 44 is connected to the first ground terminal.

[0093] The first output terminal of the third filter subunit 45 is connected to the first voltage control signal RLY1_24V terminal, and the second output terminal is connected to the second ground terminal.

[0094] First, two phases of the three-phase electrical signal are acquired as input signals UA and UB, and voltage division protection is achieved through the first resistor unit 41 and the second resistor unit 42. Each filter unit contains a capacitor and a resistor to filter the electrical signals at the input and output terminals of the first amplifier. Then, the electrical signal is amplified by the first amplifier A1, and the voltage signal UA_DSP between the two phase voltages within a specified reference range is output.

[0095] Figure 5 This is a schematic diagram of the structure of the first current sampling unit provided in an embodiment of this application. According to... Figure 5 The provided diagram shows that the first current sampling unit 151, the second current sampling unit 152, and the third current sampling unit 153 in the relay adhesion monitoring circuit are composed of the same internal structure.

[0096] The first current sampling unit 151 includes: a first current sensor CGQ and a first operational amplifier subunit 51.

[0097] The non-inverting input terminal of the first current sensor CGQ is connected to the second output terminal of the first relay unit 131, the inverting input terminal is connected to the second output terminal of the first relay unit 131, and the output terminal is connected to the input terminal of the first operational amplifier subunit 51.

[0098] The output of the first operational amplifier subunit 51 is connected to the first current control signal terminal.

[0099] The second current sampling unit 152 includes: a second current sensor CGQ2 and a second operational amplifier subunit 52.

[0100] The non-inverting input terminal of the second current sensor CGQ2 is connected to the second output terminal of the second relay unit 132, the inverting input terminal is connected to the second output terminal of the second relay unit 132, and the output terminal is connected to the input terminal of the second operational amplifier subunit 52.

[0101] The output of the second operational amplifier subunit 52 is connected to the second current control signal terminal.

[0102] The third current sampling unit 153 includes: a third current sensor CGQ3 and a third operational amplifier subunit 53.

[0103] The non-inverting input terminal of the third current sensor CGQ3 is connected to the second output terminal of the third relay unit 133, the inverting input terminal is connected to the second output terminal of the third relay unit 133, and the output terminal is connected to the input terminal of the third operational amplifier subunit 53.

[0104] The output of the third operational amplifier subunit 53 is connected to the third current control signal terminal.

[0105] In the current sampling module circuit, each operational amplifier subunit has the same structure, consisting of multiple amplifiers and RC circuits. This enables multi-stage amplification of the current signal.

[0106] Figure 6 This is a schematic flowchart illustrating a detection method provided in an embodiment of this application. It is applied to a relay adhesion detection circuit. According to... Figure 6 The provided illustrations and detection methods specifically include: S601. Determine the switching status of the relay group in the detection circuit based on the operating status of the target converter.

[0107] This application is applied to a relay sticking monitoring circuit. By acquiring multiple sampled voltages and currents, and analyzing and judging the voltages and currents, it determines whether relay sticking has occurred, thereby achieving the purpose of relay sticking detection. By detecting the voltage and current of the detection circuit, it realizes the identification of relay sticking and the measurement of input power, adds overvoltage and overcurrent protection circuits, and reduces the occurrence of relay sticking. While realizing relay sticking detection, it also monitors input power, achieving the technical effect of reducing voltage detection circuitry and saving circuit resources.

[0108] The target converter mentioned here can be understood as a PCS energy storage converter. The switching state mentioned here can be understood as the open or closed state of the relay.

[0109] Furthermore, based on the state of the PCS energy storage converter, the conduction state of the circuit can be determined, and then the switching state of the relays in the relay group on the circuit can be determined, providing a basis for the next step of analyzing relay sticking.

[0110] S602. Use the voltage sampling module to obtain multiple corresponding sampling voltages, and use the current sampling module to obtain multiple corresponding sampling currents.

[0111] S603. Determine whether all sampled voltages meet the first preset condition and whether the sampled currents simultaneously meet the second preset condition, and obtain the corresponding judgment results.

[0112] Furthermore, a voltage sampling module is used to sample multiple voltages for the three-phase power in the circuit; a current sampling module is used to collect multiple currents for the three-phase power. The circuit then determines whether the magnitude of the sampled voltage meets a first preset condition, and simultaneously, whether the sampled current meets a second preset condition, using these conditions as triggers to determine if the relay is stuck, thus obtaining the corresponding judgment result.

[0113] S604. Determine the relay adhesion result in the detection circuit based on the judgment result.

[0114] The adhesion result mentioned here can be understood as whether relay adhesion occurs in the circuit, and the number of relays that adhesion occurs in the circuit.

[0115] Furthermore, based on the judgment results, it is determined whether relay sticking has occurred in the circuit, and the number of sticking relays is further determined based on the magnitude of the sampled voltage and sampled current, thus achieving the purpose of relay sticking detection. Simultaneously, the corresponding input power is obtained based on the sampled voltage and sampled current, achieving input power monitoring while detecting relay sticking, thereby reducing production costs.

[0116] Figure 7 This is a flowchart illustrating another detection method provided in an embodiment of this application. Figure 7 This is based on the previous embodiment. Figure 7 The provided illustrations and detection methods specifically include: S701. When the target converter is de-energized, determine that the first, second, fourth, fifth, seventh, and eighth relays are in the closed state, and determine that the third, sixth, and ninth relays are in the open state.

[0117] When the PCS energy storage converter is de-energized, the first and second main relays are kept closed, and the auxiliary relays are kept open. During the de-energization process, the controller DSP first sets the first control signal RLY1_24V to a low potential, and then sets the second control signal RLY2_24V to a low potential, thereby obtaining the switching state of the relays.

[0118] S702. For any voltage sampling unit in the voltage sampling module, the first sampling voltage, the second sampling voltage, and the third sampling voltage are obtained through voltage sampling processing.

[0119] S703. For any current sampling unit in the current sampling module, the first sampling current, the second sampling current and the third sampling current are obtained through current sampling processing.

[0120] The voltage sampling module acquires the sampling voltage for detection, and the current sampling module acquires the sampling current for detection, providing data for the next step of analyzing the sticking status of the relay.

[0121] S704. When the target converter is in a de-energized state, the first switch signal is low and the second switch signal is high, determine whether the first sampled voltage, the second sampled voltage and the third sampled voltage satisfy the first relationship, and at the same time determine whether the first sampled current, the second sampled current and the third sampled current satisfy the second relationship, and obtain the corresponding first judgment result. The first judgment result indicates the state of adhesion of the first relay, the fourth relay or the seventh relay.

[0122] S705. When the target converter is in a de-energized state and both the first and second switch signals are at low levels, determine whether the first sampled voltage, the second sampled voltage, and the third sampled voltage satisfy the third relationship, and at the same time determine whether the first sampled current, the second sampled current, and the third sampled current satisfy the fourth relationship, and obtain the corresponding second judgment result. The second judgment result indicates the state of adhesion of the second relay, the fifth relay, or the eighth relay.

[0123] The first and third relationships mentioned here can be understood as the equality and inequality relationships between the three sampled voltages. The second and fourth relationships mentioned here can be understood as the equality and inequality relationships between the three sampled currents.

[0124] S706. When the judgment result is the first judgment result, it is determined that there is a relay sticking situation among the first relay, the fourth relay and the seventh relay.

[0125] S707. Determine the first number of relays stuck together based on the second relationship.

[0126] S708. Determine the adhesion results of the first relay, the fourth relay, and the seventh relay based on the relationship between the first adhesion quantity and the first sampling current, the second sampling current, and the third sampling current.

[0127] In one possible scenario, assume the first sampling voltage is UAB, the second sampling voltage is UBC, the third sampling voltage is UAC, the first sampling current is IA, the second sampling current is IB, and the third sampling current is IC.

[0128] When the first control signal RLY1_24V=0 and the second control signal RLY2_24V=24, if Equation 1 is satisfied, the first group of main relays will not stick together (there is an internal capacitive circuit, so when the first group of relays is disconnected, it will not directly drop to zero voltage).

[0129] Formula 1

[0130] Where X% represents the proportionality coefficient.

[0131] When the first control signal RLY1_24V=0 and the second control signal RLY2_24V=24, if any one of equations 2, 3, or 4 is satisfied, then one of the main relays in the first group is stuck together. Wherein: Formula 2

[0132] Equation 2 indicates that the first main relay K1 in the first relay unit of the circuit is stuck together.

[0133] Formula 3

[0134] Equation 3 indicates that the fourth relay K4 in the second relay unit of the circuit is stuck together.

[0135] Formula 4

[0136] Equation 4 indicates that the seventh relay K7 in the third relay unit of the circuit is stuck together.

[0137] When the first control signal RLY1_24V=0 and the second control signal RLY2_24V=24, if any one of equations 5, 6, or 7 is satisfied, then two relays in the first group of main relays will stick together. Wherein: Formula 5

[0138] Equation 5 indicates that the first relay K1 in the first relay unit and the fourth relay K4 in the second relay unit in the circuit are stuck together.

[0139] Formula 6

[0140] Equation 6 indicates that the first relay K1 in the first relay unit and the seventh relay K7 in the third relay unit of the circuit are stuck together.

[0141] Formula 7

[0142] Equation 7 indicates that the fourth relay K4 in the second relay unit and the seventh relay K7 in the third relay unit of the circuit are stuck together.

[0143] Formula 8

[0144] Equation 8 indicates that the first relay K1 in the first relay unit, the fourth relay K4 in the second relay unit, and the seventh relay K7 in the third relay unit in the circuit are stuck together.

[0145] Furthermore, the equality or inequality relationship between the three sampled voltages contained in Equations 1-8 represents the first relationship, and the equality or inequality relationship between the three sampled currents in Equations 1-8 represents the second relationship.

[0146] S709. When the judgment result is the second judgment result, it is determined that there is a relay sticking situation among the second relay, the fifth relay and the eighth relay.

[0147] S710. Determine the second adhesion quantity of the relay based on the fourth relationship.

[0148] S711. Determine the adhesion results of the second relay, the fifth relay, and the eighth relay based on the relationship between the second adhesion quantity and the first sampling current, the second sampling current, and the third sampling current.

[0149] When the first control signal RLY1_24V=0 and the second control signal RLY2_24V=0, if one of the following conditions is met, then while the first group of main relays (including the first, fourth, and seventh relays) are operating normally, the second group of main relays (including the second, fifth, and eighth relays) will experience sticking. Wherein: Formula 9

[0150] Equation 9 indicates that the second relay K2 in the first relay unit of the circuit is stuck together.

[0151] Formula 10

[0152] Equation 10 indicates that the fifth relay K5 in the second relay unit of the circuit is stuck together.

[0153] Formula 11

[0154] Equation 11 indicates that the sixth relay K6 in the third relay unit of the circuit is stuck together.

[0155] Formula 12

[0156] Equation 12 indicates that the second relay K2 in the first relay unit and the fifth relay in the second relay unit in the circuit are stuck together.

[0157] Formula 13

[0158] Equation 13 indicates that the second relay K2 in the first relay unit and the eighth relay K8 in the third relay unit of the circuit are stuck together.

[0159] Formula 14

[0160] Equation 14 indicates that the fifth relay K5 in the second relay unit and the eighth relay K8 in the third relay unit of the circuit are stuck together.

[0161] Formula 15

[0162] Equation 15 indicates that the second relay K2, the fifth relay K5 in the first relay unit, and the eighth relay K8 in the third relay unit of the circuit are stuck together.

[0163] Furthermore, the equality or inequality relationship between the three sampled voltages in Equation 9-15 represents the third relationship, and the equality or inequality relationship between the three sampled currents in Equation 9-15 represents the fourth relationship.

[0164] Figure 8 This is a flowchart illustrating another detection method provided in an embodiment of this application. Figure 8 Is Figure 6 This introduction is based on [the previous information]. Figure 8The provided diagram illustrates the detection method based on the relay adhesion detection circuit, which specifically includes: S801. When the target converter is powered on, ensure that all relays in the relay group are in the off state.

[0165] When the PCS energy storage converter is powered on (at this time, both sets of main relays and auxiliary relays are in the off state), the DSP controller first sets the third control signal RLY3_24V and the first control signal RLY1_24V to a high potential. After the bus capacitor is fully charged, it sets the second control signal RLY2_24V to a high potential, and then sets the third control signal RLY3_24V to a low potential. (The first control signal RLY1_24V is the control signal for the first set of main relays, the second control signal RLY2_24V is the control signal for the second set of main relays, and the third control signal RLY3_24V is the control signal for the auxiliary relays).

[0166] S802. For any voltage sampling unit in the voltage sampling module, the first sampling voltage, the second sampling voltage, and the third sampling voltage are obtained through voltage sampling processing.

[0167] S803. For any current sampling unit in the current sampling module, the first sampling current, the second sampling current and the third sampling current are obtained through current sampling processing.

[0168] The voltage sampling module acquires the sampling voltage for detection, and the current sampling module acquires the sampling current for detection, providing data for the next step of analyzing the sticking status of the relay.

[0169] S804. When the target converter is powered on, the first switch signal is high, and the second and third switch signals are both low, determine whether the first sampling voltage, the second sampling voltage, and the third sampling voltage satisfy the fifth relationship, and at the same time determine whether the first sampling current, the second sampling current, and the third sampling current satisfy the sixth relationship, and obtain the corresponding third judgment result. The third judgment result characterizes the state of adhesion of the third relay, the sixth relay, or the ninth relay caused by the last power failure of the detection circuit.

[0170] S805. When the target converter is powered on, the first switch signal is high, and the second and third switch signals are both low, determine whether the first sampled voltage, the second sampled voltage, and the third sampled voltage satisfy the seventh relationship, and at the same time determine whether the first sampled current, the second sampled current, and the third sampled current satisfy the eighth relationship, and obtain the corresponding fourth judgment result. The fourth judgment result indicates the state of sticking of the first relay, the fourth relay, or the seventh relay when powered on.

[0171] S806. When the target converter is powered on, the first and third switch signals are both high, and the second switch signal is low, determine whether the first, second, and third sampled voltages satisfy the ninth relationship, and whether the first, second, and third sampled currents satisfy the tenth relationship, and obtain the corresponding fifth judgment result. The fifth judgment result indicates the state of sticking of the third, sixth, or ninth relays when powered on.

[0172] S807. When the target converter is powered on, the first and second switch signals are both high, and the third switch signal is low, determine whether the first sampled voltage, the second sampled voltage, and the third sampled voltage satisfy the eleventh relationship, and at the same time determine whether the first sampled current, the second sampled current, and the third sampled current satisfy the twelfth relationship, and obtain the corresponding sixth judgment result. The sixth judgment result indicates the state of the second relay, the fifth relay, or the eighth relay sticking together when powered on.

[0173] S808. When the judgment result is the third judgment result, it is determined that there was relay sticking in the third, sixth and ninth relays when the target converter was last powered off.

[0174] S809. Determine the third adhesion quantity of the relay based on the sixth relationship.

[0175] S810. Determine the adhesion results of the third relay, the sixth relay, and the ninth relay based on the relationship between the third adhesion quantity and the first sampling current, the second sampling current, and the third sampling current.

[0176] When the first control signal RLY1_24V=24, the second control signal RLY2_24V=0, and the third control signal RLY3_24V=0, and the following condition is met, it is determined that the auxiliary relay has stuck.

[0177] Formula 16

[0178] Equation 16 indicates that the third relay K3 became stuck when the PCS energy storage converter was de-energized in the circuit.

[0179] Formula 17

[0180] Equation 17 indicates that when the PCS energy storage converter was de-energized in the circuit, the sixth relay K6 became stuck.

[0181] Formula 18

[0182] Equation 18 indicates that when the PCS energy storage converter was de-energized in the circuit, the ninth relay K9 became stuck.

[0183] Formula 19

[0184] Equation 19 indicates that when the PCS energy storage converter was de-energized in the circuit, the third relay K3 and the ninth relay K9 became stuck together.

[0185] Formula 20

[0186] Equation 20 indicates that when the PCS energy storage converter was de-energized in the circuit, the sixth relay K6 and the ninth relay K9 became stuck together.

[0187] Formula 21

[0188] Equation 21 indicates that when the PCS energy storage converter was de-energized in the circuit, the third relay K3 and the ninth relay K9 became stuck together.

[0189] Formula 22

[0190] Equation 22 indicates that when the PCS energy storage converter was de-energized in the circuit, the third relay K3, the sixth relay K6, and the ninth relay K9 became stuck together.

[0191] Furthermore, the equality or inequality relationship between the three sampled voltages in Equation 16-22 represents the fifth relationship, and the equality or inequality relationship between the three sampled currents in Equation 16-22 represents the sixth relationship.

[0192] S811. When the judgment result is the fourth judgment result, it is determined that there is relay sticking among the first relay, fourth relay and seventh relay when the target converter is powered on.

[0193] S812. Determine the fourth adhesion quantity of the relay based on the seventh relationship.

[0194] S813. Determine the adhesion results of the first relay, the fourth relay, and the seventh relay based on the relationship between the fourth adhesion quantity and the first sampling voltage, the second sampling voltage, and the third sampling voltage.

[0195] When the first control signal RLY1_24V=24, the second control signal RLY2_24V=0, and the third control signal RLY3_24V=0, the first group of relays will stick together when the following condition is met.

[0196] Formula 23

[0197] Equation 23 indicates that when the PCS energy storage converter in the circuit is powered on, the first relay K1 becomes stuck.

[0198] Formula 24

[0199] Equation 24 indicates that when the PCS energy storage converter in the circuit is powered on, the fourth relay K4 becomes stuck.

[0200] Formula 25

[0201] Equation 25 indicates that when the PCS energy storage converter in the circuit is powered on, the seventh relay K7 becomes stuck.

[0202] Formula 26

[0203] Equation 26 indicates that when the PCS energy storage converter in the circuit is powered on, the first relay K1 and the fourth relay K4 become stuck together.

[0204] Formula 27

[0205] Equation 27 indicates that when the PCS energy storage converter in the circuit is powered on, the first relay K1 and the seventh relay K7 become stuck together.

[0206] Formula 28

[0207] Equation 28 indicates that when the PCS energy storage converter in the circuit is powered on, the fourth relay K4 and the seventh relay K7 become stuck together.

[0208] Formula 29

[0209] Equation 29 indicates that when the PCS energy storage converter in the circuit is powered on, the first relay K1, the fourth relay K4, and the seventh relay K7 become stuck together.

[0210] Furthermore, the equality or inequality relationship between the three sampled voltages in Equations 23-29 represents the seventh relationship, and the equality or inequality relationship between the three sampled currents in Equations 23-29 represents the eighth relationship.

[0211] S814. When the judgment result is the fifth judgment result, it is determined that there is relay sticking in the third, sixth and ninth relays when the target converter is powered on.

[0212] S815. Determine the fifth adhesion quantity of the relay based on the tenth relationship.

[0213] S816. Determine the adhesion results of the third, sixth, and ninth relays based on the relationship between the fifth adhesion quantity and the first, second, and third sampling currents.

[0214] When the first control signal RLY1_24V=24, the second control signal RLY2_24V=0, and the third control signal RLY3_24V=24, and when condition 30 is met, both the first group of main relays and auxiliary relays will operate normally without sticking. Wherein: Formula 30

[0215] When the first control signal RLY1_24V=24, the second control signal RLY2_24V=0, and the third control signal RLY3_24V=24, and the following condition is met, the relay sticking detection circuit corresponding to the three-phase inputs A, B, and C will operate normally, while the auxiliary relays will stick. Where: Formula 31

[0216] Equation 31 indicates that when the PCS energy storage converter in the circuit is powered on, the third relay K3 becomes stuck.

[0217] Formula 32

[0218] Equation 32 indicates that when the PCS energy storage converter in the circuit is powered on, the sixth relay K6 of the B-phase auxiliary relay becomes stuck.

[0219] Formula 33

[0220] Equation 33 indicates that when the PCS energy storage converter in the circuit is powered on, the ninth relay K9 becomes stuck.

[0221] Formula 34

[0222] Equation 34 indicates that when the PCS energy storage converter in the circuit is powered on, the third relay K3 and the sixth relay K6 of the auxiliary relays of phases A and B become stuck together.

[0223] Formula 35

[0224] Equation 35 indicates that when the PCS energy storage converter in the circuit is powered on, the third relay K3 and the ninth relay K9 of the auxiliary relays of phases A and C become stuck together.

[0225] Formula 36

[0226] Equation 36 indicates that when the PCS energy storage converter in the circuit is powered on, the sixth relay K6 and the ninth relay K9 corresponding to the auxiliary relays of phases B and C become stuck together.

[0227] Formula 37

[0228] Equation 37 indicates that when the PCS energy storage converter in the circuit is powered on, the third relay K3, the sixth relay K6, and the ninth relay K9 corresponding to the auxiliary relays of phases A, B, and C become stuck together.

[0229] Furthermore, the equality or inequality relationship between the three sampled voltages in Equations 30-37 represents the ninth relationship, and the equality or inequality relationship between the three sampled currents in Equations 30-37 represents the tenth relationship.

[0230] S817. When the judgment result is the sixth judgment result, it is determined that there is relay sticking in the second, fifth and eighth relays when the target converter is powered on.

[0231] S818. Determine the sixth adhesion quantity of the relay based on the twelfth relationship.

[0232] S819. Determine the adhesion results of the second, fifth, and eighth relays based on the relationship between the sixth adhesion quantity and the first, second, and third sampling currents.

[0233] When the first control signal RLY1_24V=24, the second control signal RLY2_24V=24, and the third control signal RLY3_24V=0, the second group of main relays will stick together if the following condition is met.

[0234] Formula 38

[0235] Equation 38 indicates that when the PCS energy storage converter in the circuit is powered on, the second relay K2 corresponding to the second group of main relays in phase A becomes stuck.

[0236] Formula 39

[0237] Equation 39 indicates that when the PCS energy storage converter in the circuit is powered on, the fifth relay K5 corresponding to the second group of main relays in phase B becomes stuck.

[0238] Formula 40

[0239] Equation 40 indicates that when the PCS energy storage converter in the circuit is powered on, the eighth relay K8 corresponding to the second group of main relays in phase C becomes stuck.

[0240] Formula 41

[0241] Equation 41 indicates that when the PCS energy storage converter in the circuit is powered on, the second relay K2 and the fifth relay K5 corresponding to the second group of main relays in phases A and B become stuck together.

[0242] Formula 42

[0243] Equation 42 indicates that when the PCS energy storage converter in the circuit is powered on, the fifth relay K5 and the eighth relay K8 corresponding to the second group of main relays in phases B and C become stuck together.

[0244] Formula 43

[0245] Equation 43 indicates that when the PCS energy storage converter in the circuit is powered on, the second relay K2 and the eighth relay K8 corresponding to the second group of main relays in phases A and C become stuck together.

[0246] Formula 44

[0247] Equation 44 indicates that when the PCS energy storage converter in the circuit is powered on, the second relay K2, the fifth relay K5, and the eighth relay K8 corresponding to the second group of main relays in phases A, B, and C become stuck together.

[0248] Furthermore, the equality or inequality relationship between the three sampled voltages in Equations 38-44 represents the eleventh relationship, and the equality or inequality relationship between the three sampled currents in Equations 38-44 represents the twelfth relationship.

[0249] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above description is only a specific embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A relay adhesion detection circuit, characterized in that, include: AC power supply unit, leakage current sensor, relay group, voltage sampling module and current sampling module; The output terminal of the AC power supply is connected to the input terminal of the leakage current sensor; The output terminal of the leakage current sensor is connected to the input terminal of the relay group; The first output terminal of the relay group is connected to the input terminal of the voltage sampling module, and the second output terminal is connected to the input terminal of the current sampling module. The relay group includes: a first relay unit, a second relay unit, and a third relay unit; the voltage sampling module includes: a first voltage sampling unit, a second voltage sampling unit, and a third voltage sampling unit; the current sampling module includes: a first current sampling unit, a second current sampling unit, and a third current sampling unit; the first relay unit includes a first relay, a second relay, a third relay, a first resistor, and a second resistor; the second relay unit includes a fourth relay, a fifth relay, a sixth relay, a third resistor, and a fourth resistor; the third relay unit includes a seventh relay, an eighth relay, a ninth relay, a fifth resistor, and a sixth resistor. The input terminal of the first relay unit is connected to the first output terminal of the leakage current sensor, the first output terminal is connected to the first input terminal of the voltage sampling module, and the second output terminal is connected to the first input terminal of the current sampling module. The input terminal of the second relay unit is connected to the second output terminal of the leakage current sensor, the first output terminal is connected to the second input terminal of the voltage sampling module, and the second output terminal is connected to the second input terminal of the current sampling module. The input terminal of the third relay unit is connected to the third output terminal of the leakage current sensor, the first output terminal is connected to the third input terminal of the voltage sampling module, and the second output terminal is connected to the third input terminal of the current sampling module. The first input terminal of the first voltage sampling unit is connected to the first output terminal of the first relay unit, and the second input terminal is connected to the first output terminal of the second relay unit. The first input terminal of the second voltage sampling unit is connected to the first output terminal of the second relay unit, and the second input terminal is connected to the first output terminal of the third relay unit; The first input terminal of the third voltage sampling unit is connected to the first output terminal of the third relay unit, and the second input terminal is connected to the first output terminal of the first relay unit. The current sampling module includes: a first current sampling unit, a second current sampling unit, and a third current sampling unit; The input terminal of the first current sampling unit is connected to the second output terminal of the first relay unit; The input terminal of the second current sampling unit is connected to the second output terminal of the second relay unit; The input terminal of the third current sampling unit is connected to the second output terminal of the third relay unit; One end of the first relay is connected to the first output terminal of the leakage current sensor, and the other end is connected to the first node via one end of the first resistor, one end of the second relay, the first input terminal of the first voltage sampling unit, and the first input terminal of the third voltage sampling unit. The other end of the second relay is connected to the other end of the third relay and the input terminal of the first current sampling unit to the second node; The other end of the first resistor is connected to one end of the second resistor; The other end of the second resistor is connected to one end of the third relay; One end of the fourth relay is connected to the second output terminal of the leakage current sensor, and the other end is connected to the third node via one end of the third resistor, one end of the fifth relay, the second input terminal of the first voltage sampling unit, and the first input terminal of the second voltage sampling unit. The other end of the fifth relay is connected to the other end of the sixth relay and the input terminal of the second current sampling unit to the fourth node; The other end of the third resistor is connected to one end of the fourth resistor; The other end of the fourth resistor is connected to one end of the sixth relay; One end of the seventh relay is connected to the third output terminal of the leakage current sensor, and the other end is connected to the fifth node via one end of the fifth resistor, one end of the eighth relay, the second input terminal of the second voltage sampling unit, and the second input terminal of the third voltage sampling unit. The other end of the eighth relay is connected to the sixth node along with the other end of the ninth relay and the input terminal of the third current sampling unit; The other end of the fifth resistor is connected to one end of the sixth resistor; The other end of the sixth resistor is connected to one end of the ninth relay; The switching states of the first, fourth, and seventh relays are controlled by a first switching signal; the switching states of the second, fifth, and eighth relays are controlled by a second switching signal; and the switching states of the third, sixth, and ninth relays are controlled by a third switching signal.

2. The circuit according to claim 1, characterized in that, The AC power supply group includes: a first AC power supply, a second AC power supply, and a third AC power supply; The output terminal of the first AC power supply is connected to the first input terminal of the leakage current sensor; The output terminal of the second AC power supply is connected to the second input terminal of the leakage current sensor; The output terminal of the third AC power supply is connected to the third input terminal of the leakage current sensor.

3. The circuit according to claim 1, characterized in that, The first voltage sampling unit, the second voltage sampling unit, and the third voltage sampling unit have the same internal structure; The first voltage sampling unit includes: a first resistor subunit, a second resistor subunit, a first filter subunit, a second filter subunit, a third filter subunit, and a first amplifier. The first resistor subunit and the second resistor subunit are each composed of multiple resistors connected in series. One end of the first resistor subunit is connected to the first output terminal of the first relay unit, and the other end is connected to the negative input terminal of the first amplifier and the input terminal of the first filter subunit. The output terminal of the first filtering subunit is connected to the output terminal of the first amplifier and the input terminal of the third filtering subunit; One end of the second resistor subunit is connected to the first output terminal of the second relay unit, and the other end is connected to the positive input terminal of the first amplifier and the input terminal of the second filter subunit; The output terminal of the second filter subunit is connected to the first ground terminal; The first output terminal of the third filter subunit is connected to the first voltage control signal terminal, and the second output terminal is connected to the second ground terminal.

4. The circuit according to claim 1, characterized in that, The first current sampling unit, the second current sampling unit, and the third current sampling unit are each composed of the same internal structure; The first current sampling unit includes: a first current sensor and a first operational amplifier subunit; The non-inverting input terminal of the first current sensor is connected to the second output terminal of the first relay unit, the inverting input terminal is connected to the second output terminal of the first relay unit, and the output terminal is connected to the input terminal of the first operational amplifier subunit. The output of the first operational amplifier subunit is connected to the first current control signal terminal; The second current sampling unit includes: a second current sensor and a second operational amplifier subunit; The non-inverting input terminal of the second current sensor is connected to the second output terminal of the second relay unit, the inverting input terminal is connected to the second output terminal of the second relay unit, and the output terminal is connected to the input terminal of the second operational amplifier subunit. The output of the second operational amplifier subunit is connected to the second current control signal terminal; The third current sampling unit includes: a third current sensor and a third operational amplifier subunit; The positive input terminal of the third current sensor is connected to the second output terminal of the third relay unit, the negative input terminal is connected to the second output terminal of the third relay unit, and the output terminal is connected to the input terminal of the third operational amplifier subunit. The output of the third operational amplifier subunit is connected to the third current control signal terminal.

5. The circuit according to claim 1, characterized in that, The circuit further includes: a first fuse, a second fuse, a third fuse, a first anti-interference module, a second anti-interference module, a third anti-interference module, a first varistor, a second varistor, a third varistor, a first discharge tube, a second discharge tube, and a third discharge tube; One end of the first fuse is connected to the first output terminal of the AC power supply, and the other end is connected to one end of the first anti-interference module, one end of the first varistor, and the first input terminal of the leakage current sensor. The other end of the first anti-interference module is connected to the third grounding terminal; The other end of the first varistor is connected to one end of the first discharge tube; The other end of the first discharge tube is connected to the fourth grounding terminal; One end of the second fuse is connected to the second output terminal of the AC power supply, and the other end is connected to one end of the second anti-interference module, one end of the second varistor, and the second input terminal of the leakage current sensor. The other end of the second anti-interference module is connected to the third grounding terminal; The other end of the second varistor is connected to one end of the second discharge tube; The other end of the second discharge tube is connected to the fifth grounding terminal; One end of the third fuse is connected to the third output terminal of the AC power supply, and the other end is connected to one end of the third anti-interference module, one end of the third varistor, and the third input terminal of the leakage current sensor. The other end of the third anti-interference module is connected to the third grounding terminal; The other end of the third varistor is connected to one end of the third discharge tube; The other end of the third discharge tube is connected to the sixth grounding terminal.

6. A method for detecting relay adhesion, applied to the relay adhesion detection circuit according to any one of claims 1-5, characterized in that, include: Determine the switching status of the relay group in the detection circuit based on the operating status of the target converter; Multiple sampled voltages are obtained using the voltage sampling module, and multiple sampled currents are obtained using the current sampling module. Determine whether all the sampled voltages meet the first preset condition and whether the sampled current simultaneously meets the second preset condition, and obtain the corresponding determination result; The relay adhesion result in the detection circuit is determined based on the judgment result.

7. The method according to claim 6, characterized in that, Determining the switching state of the relay group in the detection circuit based on the operating state of the target converter includes: When the target converter is in a de-energized state, it is determined that the first relay, the second relay, the fourth relay, the fifth relay, the seventh relay, and the eighth relay are in a closed state, and the third relay, the sixth relay, and the ninth relay are in an open state. When the target converter is powered on, it is determined that all relays in the relay group are in the off state.

8. The method according to claim 7, characterized in that, The method of obtaining multiple sampled voltages using a voltage sampling module and multiple sampled currents using a current sampling module includes: For any voltage sampling unit in the voltage sampling module, the first sampling voltage, the second sampling voltage, and the third sampling voltage are obtained through voltage sampling processing. For any current sampling unit in the current sampling module, the first sampling current, the second sampling current, and the third sampling current are obtained through current sampling processing.

9. The method according to claim 8, characterized in that, The determination of whether all the sampled voltages meet the first preset condition and whether all the sampled currents simultaneously meet the second preset condition, to obtain the corresponding determination result, includes: When the target converter is in a power-off state, the first switch signal is low and the second switch signal is high, it is determined whether the first sampled voltage, the second sampled voltage and the third sampled voltage satisfy the first relationship, and at the same time whether the first sampled current, the second sampled current and the third sampled current satisfy the second relationship, and the corresponding first judgment result is obtained. The first judgment result indicates that at least one of the first relay, the fourth relay and the seventh relay is stuck together. When the target converter is in a de-energized state and both the first and second switching signals are at a low level, it is determined whether the first sampling voltage, the second sampling voltage, and the third sampling voltage satisfy the third relationship, and at the same time, it is determined whether the first sampling current, the second sampling current, and the third sampling current satisfy the fourth relationship, and a corresponding second judgment result is obtained. The second judgment result indicates that at least one of the second relay, the fifth relay, and the eighth relay is stuck together.

10. The method according to claim 9, characterized in that, The step of determining the relay adhesion result in the detection circuit based on the judgment result includes: When the judgment result is the first judgment result, it is determined that there is relay sticking among the first relay, the fourth relay, and the seventh relay; The first number of relays stuck together is determined based on the second relationship; The adhesion results of the first relay, the fourth relay, and the seventh relay are determined based on the relationship between the first adhesion quantity and the first sampling current, the second sampling current, and the third sampling current. When the judgment result is the second judgment result, it is determined that there is relay sticking among the second relay, the fifth relay, and the eighth relay; The second adhesion quantity of the relay is determined according to the fourth relationship; The adhesion results of the second, fifth, and eighth relays are determined based on the relationship between the second adhesion quantity and the first, second, and third sampling currents.

11. The method according to claim 8, characterized in that, The determination of whether all the sampled voltages meet the first preset condition and whether all the sampled currents simultaneously meet the second preset condition, to obtain the corresponding determination result, includes: When the target converter is powered on, the first switch signal is high, and the second and third switch signals are both low, it is determined whether the first sampled voltage, the second sampled voltage, and the third sampled voltage satisfy the fifth relationship, and at the same time, whether the first sampled current, the second sampled current, and the third sampled current satisfy the sixth relationship, and a corresponding third judgment result is obtained. The third judgment result represents the state in which at least one of the third relay, the sixth relay, and the ninth relay is stuck together due to the last power failure of the detection circuit. When the target converter is powered on, the first switch signal is high, and the second switch signal and the third switch signal are both low, it is determined whether the first sampled voltage, the second sampled voltage, and the third sampled voltage satisfy the seventh relationship, and whether the first sampled current, the second sampled current, and the third sampled current satisfy the eighth relationship, to obtain the corresponding fourth judgment result. The fourth judgment result indicates that at least one of the first relay, the fourth relay, and the seventh relay is stuck together when powered on. When the target converter is powered on, the first switch signal and the third switch signal are both high, and the second switch signal is low, it is determined whether the first sampled voltage, the second sampled voltage and the third sampled voltage satisfy the ninth relationship, and at the same time whether the first sampled current, the second sampled current and the third sampled current satisfy the tenth relationship, to obtain the corresponding fifth judgment result. The fifth judgment result indicates that at least one of the third relay, the sixth relay and the ninth relay is stuck together when powered on. When the target converter is powered on, the first switch signal and the second switch signal are both at high level, and the third switch signal is at low level, it is determined whether the first sampled voltage, the second sampled voltage and the third sampled voltage satisfy the eleventh relationship, and at the same time whether the first sampled current, the second sampled current and the third sampled current satisfy the twelfth relationship, to obtain the corresponding sixth judgment result. The sixth judgment result indicates that at least one of the second relay, the fifth relay and the eighth relay is stuck together when powered on.

12. The method according to claim 11, characterized in that, The step of determining the relay adhesion result in the detection circuit based on the judgment result includes: When the judgment result is the third judgment result, it is determined that there was relay sticking in the third, sixth and ninth relays when the target converter was last powered off. The third adhesion quantity of the relay is determined based on the sixth relationship; The adhesion results of the third relay, the sixth relay, and the ninth relay are determined based on the relationship between the third adhesion quantity and the first sampling current, the second sampling current, and the third sampling current; When the judgment result is the fourth judgment result, it is determined that there is relay sticking among the first relay, fourth relay and seventh relay when the target converter is powered on; The fourth adhesion quantity of the relay is determined based on the eighth relationship described above; The adhesion results of the first relay, the fourth relay, and the seventh relay are determined based on the relationship between the fourth adhesion quantity and the first sampling current, the second sampling current, and the third sampling current. When the judgment result is the fifth judgment result, it is determined that there is relay sticking in the third, sixth and ninth relays when the target converter is powered on; The fifth adhesion quantity of the relay is determined based on the tenth relationship described above; The adhesion results of the third relay, the sixth relay, and the ninth relay are determined based on the relationship between the fifth adhesion quantity and the first sampling current, the second sampling current, and the third sampling current; When the judgment result is the sixth judgment result, it is determined that there is relay sticking in the second, fifth and eighth relays when the target converter is powered on; The sixth adhesion quantity of the relay is determined based on the twelfth relationship described above; The adhesion results of the second relay, the fifth relay, and the eighth relay are determined based on the relationship between the sixth adhesion quantity and the first sampling current, the second sampling current, and the third sampling current.

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