Relay control circuit, control method and inverter system

Abstract

The invention discloses a relay control circuit, a control method and an inverter system, and belongs to the field of inverter systems. The relay control circuit comprises at least one voltage sampling module; the at least one switch module is connected with the at least one series-connected relay in a one-to-one correspondence manner; the control module is connected with the switch module and is used for controlling the switch module to switch on when the remaining relays except the first target relay in the at least one series-connected relays are all closed and the actual voltage at the two ends of the first target relay is smaller than a target threshold value; controlling the first target relay to be closed through a switch module corresponding to the first target relay; the first target relay is the last relay close to one side of the power grid. According to the relay control circuit, the impact current in the loop can be reduced, the main contact of the relay and components in the loop are protected, the service life of an inverter system is prolonged, and the reliability of the inverter system is improved.

Description

Technical Field

[0001] The present application belongs to the field of inverter systems, and in particular, relates to a relay control circuit, a control method and an inverter system. Background Art

[0002] The three-level inverter converts direct current into alternating current and connects it to the grid through two sets of grid-connected relays. After completing the relay self-test, the controller issues a command to make the relays energize in sequence. When the last relay is energized, a large impact current will be generated due to the voltage difference between its two ends and the impedance in the circuit. In the related art, when designing the control circuit of the grid-connected relay, only the function of realizing its energization to connect the inverter to the grid is considered, and the impact of the impact current generated by the grid-connected relay at the moment of energization on the main contacts of the relay and circuit components is ignored. This impact will seriously affect the reliability and life of the inverter after long-term accumulation. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a relay control circuit, a control method and an inverter system, which can reduce the impact current in the circuit, protect the main contacts of the relay and the components in the circuit, and improve the service life and reliability of the inverter system.

[0004] In a first aspect, the present application provides a relay control circuit, which is applied to an inverter circuit, wherein the inverter circuit includes at least one phase branch, each of the phase branches is respectively provided with at least one relay connected in series; the relay control circuit includes:

[0005] At least one voltage sampling module, the voltage sampling module is used to collect the actual voltage across the relay;

[0006] At least one switch module, the at least one switch module being connected in a one-to-one correspondence with the at least one relay connected in series;

[0007] A control module, the control module is connected to the switch module, and is used to control the first target relay to be closed through the switch module corresponding to the first target relay when all the remaining relays except the first target relay in the at least one series-connected relay are closed and the actual voltage across the first target relay is less than a target threshold; the first target relay is the last relay close to the power grid side.

[0008] According to the relay control circuit of the present application, by controlling the last relay to close to achieve grid connection when the actual voltage across the last relay is small, the impact current in the circuit can be reduced, the main contacts of the relay and components in the circuit can be protected, and the service life and reliability of the inverter system can be improved; and the circuit structure is simple, easy to implement, and the design cost is low.

[0009] According to one embodiment of the present application, the switch module includes:

[0010] A third transistor, the emitter of the third transistor is grounded, the collector of the third transistor is connected to the relay corresponding to the switch module in the at least one relay connected in series; the base of the third transistor is connected to the control module, and when the third transistor is turned on, the relay corresponding to the third transistor is closed.

[0011] According to an embodiment of the present application, when the inverter circuit includes a plurality of phase branches, each of the switch modules includes a plurality of third transistors having the same number as the phase branches, wherein:

[0012] A target third transistor among the plurality of third transistors is connected to a second target relay in a first target phase branch among the plurality of phase branches; the second target relay is a relay corresponding to the switch module among the at least one serially connected relay included in the first target phase branch;

[0013] The bases of the plurality of third transistors included in the same switch module are respectively connected to the control module.

[0014] According to an embodiment of the present application, the switch module includes: a fourth resistor, and the fourth resistor is connected between the base of the third transistor and the control module.

[0015] According to one embodiment of the present application, the control module includes:

[0016] A controller; when all the remaining relays except the first target relay in the at least one serially connected relay are closed and the actual voltage across the first target relay is less than the target threshold, the controller sends a high level signal to the switch module corresponding to the first target relay to control the switch module to be turned on;

[0017] A first resistor and a second resistor connected in series; the first resistor is used to access a first voltage, and the first resistor is connected to an end of the relay away from the switch module;

[0018] A second transistor, the base of the second transistor is connected to the controller, the emitter of the second transistor is grounded, and the collector of the second transistor is connected to the second resistor; when the controller sends a high level signal to the second transistor, the second transistor is turned on.

[0019] According to one embodiment of the present application, the control module includes:

[0020] A third resistor is connected between the base of the second transistor and the controller.

[0021] According to one embodiment of the present application, it also includes:

[0022] A PMOS tube, wherein the gate of the PMOS tube is connected between the first resistor and the second resistor connected in series, the source of the PMOS tube is used to connect to the first voltage, and the drain of the PMOS tube is respectively connected to one end of each of the relays away from the switch module;

[0023] A diode, wherein the cathode of the diode is connected to the drain of the PMOS tube, and the anode of the diode is used to access a second voltage, wherein the second voltage is less than the first voltage; after the first target relay is closed, the controller sends a low-level signal to the second transistor, the PMOS tube is turned off, and the second voltage is accessed to the relay.

[0024] In a second aspect, the present application provides a control method based on the relay control circuit as described in the first aspect, the method comprising:

[0025] controlling the remaining relays of the at least one serially connected relay except the first target relay to close;

[0026] Obtaining actual voltage across the first target relay;

[0027] When the actual voltage is less than the target threshold, the first target relay is controlled to be closed.

[0028] According to the control method of the present application, by controlling the last relay to close to achieve grid connection when the actual voltage across the last relay is small, the impact current in the circuit can be reduced, the main contacts of the relay and components in the circuit can be protected, and the service life and reliability of the inverter system can be improved; and the circuit structure is simple, easy to implement, and the design cost is low.

[0029] In a third aspect, the present application provides an inverter system, comprising:

[0030] An inverter circuit, the inverter circuit comprising at least one phase branch, the phase branch being provided with at least one relay connected in series;

[0031] As described in the first aspect, the relay control circuit is connected to the relay.

[0032] In a fourth aspect, the present application provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the control method as described in the second aspect above.

[0033] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the control method described in the second aspect above.

[0034] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects:

[0035] By controlling the last relay to close to achieve grid connection when the actual voltage across the last relay is small, the impact current in the circuit can be reduced, the main contacts of the relay and components in the circuit can be protected, and the service life and reliability of the inverter system can be improved; the circuit structure is simple, easy to implement, and the design cost is low.

[0036] Furthermore, by respectively providing a corresponding third transistor for each relay, individual control of the relay can be achieved, with higher control flexibility and control accuracy, applicable to a variety of inverter scenarios, and further improving the reliability and universality of the inverter system.

[0037] Furthermore, by switching to a smaller second voltage to power the relay to maintain the relay in an energized state after the inverter system is connected to the grid, the loss of the relay coil can be reduced, thereby extending the life of the relay coil and further extending the service life of the inverter system.

[0038] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0040] Figure 1 It is one of the structural schematic diagrams of the relay control circuit provided in the embodiment of the present application;

[0041] Figure 2 This is the second structural schematic diagram of the relay control circuit provided in the embodiment of the present application;

[0042] Figure 3 It is one of the flow charts of the control method provided in the embodiment of the present application;

[0043] Figure 4 This is the second flow chart of the control method provided in the embodiment of the present application;

[0044] Figure 5 It is a schematic diagram of the structure of the control device provided in the embodiment of the present application. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0046] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0047] The relay control circuit, the control method of the relay control circuit and the inverter system provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0048] like Figure 1 As shown, the relay control circuit includes: at least one voltage sampling module 110, at least one switch module and a control module.

[0049] In this embodiment, the relay control circuit is applied to the inverter circuit.

[0050] The inverter circuit includes at least one phase branch, and each phase branch is respectively provided with at least one relay connected in series.

[0051] The inverter circuit may be a single-phase inverter or a multi-phase inverter.

[0052] The voltage sampling module 110 is connected in parallel with two ends of the relay.

[0053] The voltage sampling module 110 is used to collect the actual voltage across the relay.

[0054] In some embodiments, one relay may be connected in parallel to one voltage sampling module 110 .

[0055] In some embodiments, when the inverter system includes multi-phase branches, one voltage sampling module 110 can be connected in parallel with multiple relays located in different phase branches and with the same relative positions, that is, one voltage sampling module 110 is connected in parallel with a group of relays.

[0056] A group of relays includes multiple relays located in different phase branches and at the same position.

[0057] like Figure 1 As shown, taking a three-phase inverter as an example, 1 to L2 relays are respectively arranged in series on each phase branch, where L2 ≥ 1 and is an integer.

[0058] Among them, the first relay located on each phase branch constitutes a group of relays, namely the first group of relays; the second relay located on each phase branch constitutes a group of relays, namely the second group of relays, and so on, 1 to L2 groups of relays can be obtained.

[0059] Then L2 voltage sampling modules 110 may be provided correspondingly, wherein one voltage sampling module 110 is connected in parallel with a group of relays.

[0060] The voltage sampling module 110 and the switch module are arranged in a one-to-one correspondence.

[0061] The switch module is used to control the opening and closing of the relay corresponding to the voltage sampling module 110 arranged correspondingly thereto.

[0062] The switch module may include a transistor.

[0063] It should be noted that one switch module can be set in one-to-one correspondence with one relay, or one switch module can also be set in one-to-one correspondence with a group of relays.

[0064] It is understandable that during the operation of the inverter, the actual voltage across the relay may be a value that changes in real time.

[0065] The control module is used to control the switch module to control the opening and closing of the relay corresponding to the switch module.

[0066] During the actual execution process, when all the remaining relays except the first target relay in at least one series-connected relay are closed and the actual voltage across the first target relay is less than the target threshold, the first target relay is controlled to be closed by the switch module corresponding to the first target relay.

[0067] The first target relay is the last closed relay on the same phase line, for example, the first target relay may be the last relay close to the power grid.

[0068] Continue to refer Figure 1 , the first target relay may be relay L2.

[0069] The target threshold is a lower value.

[0070] Target thresholds can be user-defined.

[0071] In the case where the actual voltage is less than the target threshold, it can be approximately considered that the voltage across the first target relay is small.

[0072] For example, Figure 4 As shown, during the off-grid switching process, the control module first controls the other relays except the first target relay to be energized and controls the first target relay to be disconnected through the switch module; the voltage sampling module 110 samples the actual voltage at both ends of the first target relay in real time and sends it to the control module, and the control module compares the size relationship between the actual voltage and the target threshold.

[0073] When the actual voltage is not less than the target threshold, it is considered that the actual voltage is large. At this time, closing the first target relay may cause a risk of generating a large impact current, and the first target relay is controlled to remain open.

[0074] When the actual voltage is less than the target threshold, it is considered that the actual voltage is small and the risk of generating a large impact current is relatively low. At this time, the control module sends a high-level signal to the switch module corresponding to the first target relay to control the closing of the first target relay, thereby achieving grid connection.

[0075] According to the relay control circuit provided in the embodiment of the present application, by controlling the last relay to close to achieve grid connection when the actual voltage across the last relay is small, the impact current in the circuit can be reduced, the main contacts of the relay and components in the circuit can be protected, and the service life and reliability of the inverter system can be improved; and the circuit structure is simple, easy to implement, and the design cost is low.

[0076] Continue to refer Figure 1 In some embodiments, the switch module may include: a third transistor Q3.

[0077] In this embodiment, the third transistor Q3 may be an NPN transistor.

[0078] The emitter of the third triode Q3 is grounded, the collector of the third triode Q3 is connected to a relay corresponding to the switch module in at least one relay connected in series, and the base of the third triode Q3 is connected to the control module.

[0079] The control module controls the third transistor Q3 to be turned on or off by sending corresponding high and low level signals to the third transistor Q3.

[0080] If a high level signal is sent to the third transistor Q3, the third transistor Q3 is turned on; if a low level signal is sent to the third transistor Q3, the third transistor Q3 is turned off.

[0081] When the third transistor Q3 is turned on, the relay corresponding to the third transistor Q3 is closed.

[0082] When the third transistor Q3 is turned off, the relay corresponding to the third transistor Q3 is disconnected.

[0083] Continue to refer Figure 1 In some embodiments, the switch module may include: a fourth resistor R4.

[0084] In this embodiment, the fourth resistor R4 is connected between the base of the third transistor Q3 and the control module.

[0085] It can be understood that the control module controls the third transistor Q3 to be turned on or off for self-test and off-grid switching.

[0086] For example, in the actual execution process, the control module sends a high-level signal to the third transistor Q3 corresponding to the first group of relays to turn on the third transistor Q3, and the first group of relays is energized; sends a low-level signal to the third transistor Q3 corresponding to the other groups of relays to turn off the third transistor Q3, and the other groups of relays are disconnected; the actual voltage at both ends of the first group of relays is sampled by the voltage sampling module 110 corresponding to the first group of relays, so as to perform adhesion detection on the first group of relays based on the actual voltage obtained by sampling, and complete the self-test of the first group of relays;

[0087] Then, the control module sends a high-level signal to the third transistor Q3 corresponding to the second group of relays to turn on the third transistor Q3, and the second group of relays is energized; a low-level signal is sent to the third transistor Q3 corresponding to other groups of relays, and the actual voltage across the second group of relays is sampled through the voltage sampling module 110 corresponding to the second group of relays to perform self-test on the second group of relays;

[0088] And so on, until all relays have completed self-test.

[0089] After completing the self-test, the control module can send a low-level signal to the third transistor Q3 corresponding to each group of relays to control each relay to be disconnected.

[0090] The relay control circuit provided in the embodiment of the present application has a simple circuit structure, is easy to implement, and has higher control accuracy compared to software control.

[0091] like Figure 2 As shown, in some embodiments, when the inverter circuit includes a plurality of phase branches, each switch module may include a plurality of third transistors Q3 which is the same in number as the number of the phase branches.

[0092] In this embodiment, a target third transistor Q3 among the plurality of third transistors Q3 is connected to a second target relay in a first target phase branch among the plurality of phase branches.

[0093] The first target phase branch may be any phase among the multiple phases.

[0094] The second target relay is a relay corresponding to the switch module among at least one relay connected in series included in the first target phase branch.

[0095] The bases of the plurality of third triodes Q3 included in the same switch module are respectively connected to the control module.

[0096] Take a three-phase inverter as an example. Figure 2 As shown, the three-phase inverter includes three-phase branches A, B and C, and 1 to L2 relays are respectively connected in series on each phase branch; then a switch module may include three third transistors Q3, taking the switch module corresponding to the first group of relays as an example, it may include transistors: Q31, Q32 and Q33; wherein the collector of Q31 is connected to the relay arranged in the C phase branch in the first group of relays, the collector of Q32 is connected to the relay arranged in the B phase branch in the first group of relays, and the collector of Q33 is connected to the relay arranged in the A phase branch in the first group of relays.

[0097] The emitters of Q31 , Q32 and Q33 are grounded respectively, and the bases of Q31 , Q32 and Q33 are connected to the control module via the fourth resistor R4 respectively.

[0098] Taking the A-phase relay including A1 and A2 connected in series as an example, the specific implementation method is explained.

[0099] In the initial state, the MCU sends a high-level signal to turn on the second transistor Q2, so that the voltage across the coils of relays A1, A2, B1, B2, C1, and C2 is the first voltage V1. Then the MCU first sends a high-level signal to turn on the transistor Q33, and relay A1 is energized. The actual voltage across its two ends is sampled through the relay A1 voltage sampling module to complete the self-test of relay A1.

[0100] Then, the MCU sends a low-level signal to disconnect the first relay A1, and then sends a high-level signal to turn on the transistor Q36, and the relay A2 is energized. The actual voltage at both ends of the relay A2 is sampled by the voltage sampling module of the relay A2 to complete the self-test of the relay A2. Subsequently, the MCU sends a low-level signal to disconnect the transistor Q36, thereby disconnecting the relay A2.

[0101] After completing the self-test of relays A1 and A2, the MCU sends a high-level signal again to turn on transistor Q33, and relay A1 is energized. Then, the actual voltage across relay A2 is sampled. When the actual voltage across relay A2 is small, the MCU sends a high-level signal to turn on transistor Q36. At this time, relay A2 is energized, and inverter phase A is connected to the grid.

[0102] Since the actual voltage across relay A2 is small at the moment of grid connection, the impact current in the circuit is also small, thereby protecting the relay main contacts and components in the circuit.

[0103] After the inverter is connected to the grid, the MCU sends a low-level signal to turn off the PMOS tube Q1, so that the smaller second voltage V2 supplies power to the relay coil to maintain its energized state. At this time, the loss of the relay coil is also small, thereby extending the life of the relay coil.

[0104] The self-test and grid-connection logic of the B-phase relays B1, B2 and the C-phase relays C1, C2 are similar to the logic of the A-phase, and will not be elaborated herein in this application.

[0105] In actual implementation, the control logic of the three-phase relays can be carried out in parallel.

[0106] According to the relay control circuit provided in the embodiment of the present application, by respectively setting a corresponding third transistor Q3 for each relay, it is possible to achieve individual control of the relay, with higher control flexibility and control accuracy, and is suitable for a variety of inverter scenarios, further improving the reliability and universality of the inverter system.

[0107] Continue to refer Figure 1 In some embodiments, the control module may include: a controller MCU, a first resistor R1, a second resistor R2, and a second transistor Q2.

[0108] In this embodiment, the controller MCU may be a microcontroller unit (MCU).

[0109] The controller MCU is respectively connected to the base of each third transistor Q3 and the voltage sampling module 110, and is used to receive the actual voltage collected by each voltage sampling module 110, and to send high and low levels to each third transistor Q3 to control the third transistor Q3 to be turned on or off.

[0110] The first resistor R1 and the second resistor R2 are connected in series. The first resistor R1 is used to access the first voltage V1, and the first resistor R1 is connected to one end of the relay away from the switch module.

[0111] The first voltage V1 is used to provide a starting voltage for both ends of the relay coil.

[0112] The second transistor Q2 may be an NPN transistor.

[0113] The base of the second triode Q2 is connected to the controller MCU, the emitter of the second triode Q2 is grounded, and the collector of the second triode Q2 is connected to the second resistor R2.

[0114] The controller MCU is used for sending high and low level signals to the second transistor Q2 to control the on and off of the second transistor Q2.

[0115] When the second transistor Q2 receives a high-level signal, the second transistor Q2 is turned on; when the second transistor Q2 receives a low-level signal, the second transistor Q2 is turned off.

[0116] In some embodiments, the control module may further include a third resistor R3.

[0117] In this embodiment, the third resistor R3 is connected between the controller MCU and the base of the second transistor Q2.

[0118] During the actual execution process, when all the remaining relays except the first target relay in at least one series-connected relay are closed and the actual voltage across the first target relay is less than the target threshold, the controller MCU sends a high-level signal to the switch module corresponding to the first target relay to control the switch module to turn on.

[0119] For example, in the initial state, the controller MCU sends a high-level signal to turn on the second transistor Q2, so that the voltage across the relay coil is the starting voltage, and then completes the self-test by controlling the on and off of the third transistor Q3. After completing the self-test, the controller MCU sends a high level to other third transistors Q3 except the third transistor Q3 corresponding to the first target relay to control all relays on each phase branch except the first target relay to be closed; and sends a low-level signal to the third transistor Q3 corresponding to the first target relay to control the first target relay to remain open.

[0120] The controller MCU receives the actual voltage across the first target relay collected by the voltage sampling module 110 in real time, and compares the collected actual voltage with the target threshold.

[0121] When the actual voltage is not less than the target threshold, it is considered that the actual voltage is large. At this time, closing the first target relay may cause a risk of generating a large impact current, and the first target relay is controlled to remain open.

[0122] When the actual voltage is less than the target threshold, it is considered that the actual voltage is small and the risk of generating a large impact current is relatively low. At this time, the controller MCU sends a high level to the third transistor Q3 corresponding to the first target relay to turn it on, so as to control the first target relay to close, thereby achieving grid connection.

[0123] During the grid-connected process, the actual voltage across the first target relay is small, which makes the impact current in the circuit relatively small, thereby protecting the main contacts of the relay and components in the circuit and increasing the service life of the inverter system.

[0124] According to the relay control circuit provided in the embodiment of the present application, by controlling the last relay to close to achieve grid connection when the actual voltage across the last relay is small, the impact current in the circuit can be reduced, the main contacts of the relay and components in the circuit can be protected, and the service life of the inverter system can be increased.

[0125] Continue to refer Figure 1 In some embodiments, the relay control circuit may further include: a PMOS tube Q1 and a diode D1.

[0126] In this embodiment, the gate of the PMOS tube Q1 is connected between the first resistor R1 and the second resistor R2 connected in series, the source of the PMOS tube Q1 is used to connect to the first voltage V1, and the drain of the PMOS tube Q1 is respectively connected to one end of each relay away from the switch module.

[0127] The cathode of the diode D1 is connected to the drain of the PMOS tube Q1 , and the cathode of the diode D1 is respectively connected to one end of each relay away from the switch module.

[0128] The anode of the diode D1 is used to access the second voltage V2.

[0129] The second voltage V2 is smaller than the first voltage V1.

[0130] The second voltage V2 is used to supply power to the relay to maintain the relay in the closed state.

[0131] Continuing with the above embodiment as an example, when the actual voltage across the first target relay is less than the target threshold, after the controller MCU controls the first target relay to close to achieve grid connection, the controller MCU sends a low-level signal to the second transistor Q2, the second transistor Q2 is disconnected, the PMOS tube Q1 is turned off, and the second voltage V2 is connected to the relay to power the coil of each relay to maintain its energized state. By providing a smaller power supply voltage, the loss of the relay coil is relatively small, thereby extending the life of the relay coil.

[0132] According to the relay control circuit provided in the embodiment of the present application, by switching to a smaller second voltage V2 to power the relay to maintain the relay in the energized state after the inverter system is connected to the grid, the loss of the relay coil can be reduced, thereby extending the life of the relay coil and further extending the service life of the inverter system.

[0133] An embodiment of the present application also provides a control method based on the relay control circuit described in any of the above embodiments.

[0134] like Figure 3 As shown, the control method includes: step 310, step 320 and step 330.

[0135] Step 310: Control remaining relays except the first target relay in at least one relay connected in series to close;

[0136] In this step, the first target relay is the last closed relay in the same phase branch during the off-grid switching process, for example, it can be the last relay close to the grid side.

[0137] Continue to refer Figure 1 , the first target relay may be relay L2.

[0138] Step 320, obtaining the actual voltage across the first target relay;

[0139] In this step, the actual voltage is a value that changes in real time.

[0140] Step 330: When the actual voltage is less than the target threshold, control the first target relay to close.

[0141] In this step, the target threshold is a lower value.

[0142] Target thresholds can be user-defined.

[0143] In the case where the actual voltage is less than the target threshold, it can be approximately considered that the voltage across the first target relay is small.

[0144] When it is detected that the voltage across the first target relay is small, the first target relay is controlled to close to complete the grid connection.

[0145] In actual implementation, the method may be executed using the relay control circuit described in any of the above embodiments.

[0146] For example, during the off-grid switching process, the control module first controls the other relays other than the first target relay through the switch module to attract and control the first target relay to disconnect; the voltage sampling module 110 samples the actual voltage at both ends of the first target relay in real time and sends it to the control module, and the control module compares the size relationship between the actual voltage and the target threshold.

[0147] When the actual voltage is not less than the target threshold, it is considered that the actual voltage is large. At this time, closing the first target relay may cause a risk of generating a large impact current, and the first target relay is controlled to remain open.

[0148] When the actual voltage is less than the target threshold, it is considered that the actual voltage is small and the risk of generating a large impact current is relatively low. At this time, the control module sends a high-level signal to the switch module corresponding to the first target relay to control the closing of the first target relay, thereby achieving grid connection.

[0149] According to the control method provided in the embodiment of the present application, by controlling the last relay to close to achieve grid connection when the actual voltage across the last relay is small, the impact current in the circuit can be reduced, the main contacts of the relay and components in the circuit can be protected, and the service life and reliability of the inverter system can be improved; and the circuit structure is simple, easy to implement, and the design cost is low.

[0150] In some embodiments, after step 330, the method may further include:

[0151] Reduce the actual voltage across each relay.

[0152] In this embodiment, after the inverter system is connected to the grid, the actual voltage across each relay can be reduced to power the relay coil with a smaller voltage to maintain its energized state. While maintaining the stable operation of the inverter, it can also reduce the loss of the relay coil and extend the life of the relay coil.

[0153] According to the control method provided in the embodiment of the present application, by reducing the actual voltage across each relay after the inverter system is connected to the grid, it is possible to maintain the inverter in an energized state to maintain stable operation of the inverter while reducing the loss of the relay coil and extending the life of the relay coil.

[0154] Continue to refer Figure 4In some embodiments, before step 330, the method may further include:

[0155] controlling a third target relay in at least one relay connected in series to close;

[0156] obtaining the actual voltage across the third target relay;

[0157] Based on the actual voltage, a fault detection is performed on the third target relay.

[0158] In this embodiment, the third target relay may be any one of all relays that needs to be subjected to adhesion detection.

[0159] The self-check control logic of each relay is similar, and in actual implementation, it can also be implemented based on the relay control circuit described in any of the above embodiments.

[0160] For example, the control module sends a high-level signal to the third transistor Q3 corresponding to the first group of relays to turn on the third transistor Q3, and the first group of relays is energized; sends a low-level signal to the third transistor Q3 corresponding to the other groups of relays to turn off the third transistor Q3, and the other groups of relays are disconnected; the actual voltage at both ends of the first group of relays is sampled by the voltage sampling module 110 corresponding to the first group of relays, so as to perform adhesion detection on the first group of relays based on the sampled first voltage V1, and complete the self-test of the first group of relays;

[0161] Then, the control module sends a high-level signal to the third transistor Q3 corresponding to the second group of relays to turn on the third transistor Q3, and the second group of relays is energized; a low-level signal is sent to the third transistor Q3 corresponding to other groups of relays, and the actual voltage across the second group of relays is sampled through the voltage sampling module 110 corresponding to the second group of relays to perform self-test on the second group of relays;

[0162] And so on, until all relays have completed self-test.

[0163] According to the control method provided in the embodiment of the present application, by performing fault detection on each relay before switching between off-grid and on-grid, the fault of each relay can be timely checked, thereby ensuring the normal switching between off-grid and on-grid, and further improving the stability and reliability of the inverter system operation.

[0164] In the control method provided in the embodiment of the present application, the execution subject may be a control device; or may be a relay control circuit, or may be an inverter system. In the embodiment of the present application, the control device provided in the embodiment of the present application is described by taking the control method executed by the control device as an example.

[0165] An embodiment of the present application also provides a control device based on the relay control circuit described in any of the above embodiments.

[0166] like Figure 5 As shown, the control device includes: a first processing module 510 , a second processing module 520 and a third processing module 530 .

[0167] A first processing module 510 is used to control the remaining relays except the first target relay in at least one relay connected in series to close;

[0168] A second processing module 520 is used to obtain the actual voltage across the first target relay;

[0169] The third processing module 530 is used to control the first target relay to close when the actual voltage is less than the target threshold.

[0170] According to the control device provided in the embodiment of the present application, by controlling the last relay to close to achieve grid connection when the actual voltage across the last relay is small, the impact current in the circuit can be reduced, the main contacts of the relay and components in the circuit can be protected, and the service life and reliability of the inverter system can be improved; and the circuit structure is simple, easy to implement, and the design cost is low.

[0171] In some embodiments, the apparatus may further include a fourth processing module, configured to:

[0172] When the actual voltage is less than the target threshold, after the first target relay is controlled to be closed, the actual voltage across both ends of each relay is reduced.

[0173] In some embodiments, the apparatus may further include a fifth processing module, configured to:

[0174] Before controlling the remaining relays except the first target relay in the at least one relay connected in series to be closed, controlling the third target relay in the at least one relay connected in series to be closed;

[0175] obtaining the actual voltage across the third target relay;

[0176] Based on the actual voltage, a fault detection is performed on the third target relay.

[0177] The control device provided in the embodiment of the present application can achieve Figure 3 to Figure 4 To avoid repetition, the various processes implemented by the method embodiment are not described here.

[0178] An embodiment of the present application also provides an inverter system.

[0179] like Figure 1As shown, the inverter system includes: an inverter circuit and a relay control circuit as described in any of the above embodiments.

[0180] The inverter circuit includes at least one phase branch, and the phase branch is provided with at least one relay connected in series.

[0181] The relay control circuit is connected to the relay, and the specific connection method has been described in the above embodiment, which will not be repeated in this application.

[0182] The relay control circuit is used to perform self-test on the inverter system and switch between on-grid and off-grid.

[0183] According to the inverter system provided in the embodiment of the present application, by controlling the last relay to close to achieve grid connection when the actual voltage across the last relay is small, the impact current in the circuit can be reduced, the main contacts of the relay and components in the circuit can be protected, and the service life and reliability of the inverter system can be improved; and the circuit structure is simple, easy to implement, and the design cost is low.

[0184] An embodiment of the present application also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the various processes of the above-mentioned control method embodiment are implemented and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0185] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0186] An embodiment of the present application also provides a computer program product, including a computer program, which implements the above-mentioned control method when executed by a processor.

[0187] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0188] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned control method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0189] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0190] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0191] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, a disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0192] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

[0193] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0194] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A relay control circuit, characterized in that: Applied to an inverter circuit, the inverter circuit comprises at least one phase branch, each of the phase branches is respectively provided with at least one relay connected in series; The relay control circuit comprises: At least one voltage sampling module, the voltage sampling module is used to collect the actual voltage across the relay; At least one switch module, the at least one switch module being connected in a one-to-one correspondence with the at least one relay connected in series; A control module, the control module is connected to the switch module, and is used to control the first target relay to be closed through the switch module corresponding to the first target relay when all the remaining relays except the first target relay in the at least one series-connected relay are closed and the actual voltage across the first target relay is less than a target threshold; the first target relay is the last relay close to the power grid side.

2. The relay control circuit according to claim 1, characterized in that: The switch module comprises: A third transistor, the emitter of the third transistor is grounded, the collector of the third transistor is connected to the relay corresponding to the switch module in the at least one relay connected in series; the base of the third transistor is connected to the control module, and when the third transistor is turned on, the relay corresponding to the third transistor is closed.

3. The relay control circuit according to claim 2, characterized in that: In the case where the inverter circuit includes a plurality of phase branches, each of the switch modules includes a plurality of third transistors having the same number as the phase branches, wherein: A target third transistor among the plurality of third transistors is connected to a second target relay in a first target phase branch among the plurality of phase branches; the second target relay is a relay corresponding to the switch module among the at least one serially connected relay included in the first target phase branch; The bases of the plurality of third transistors included in the same switch module are respectively connected to the control module.

4. The relay control circuit according to claim 2, characterized in that: The switch module includes: a fourth resistor connected between the base of the third transistor and the control module.

5. The relay control circuit according to any one of claims 1 to 4, characterized in that: The control module comprises: A controller; when all the remaining relays except the first target relay in the at least one serially connected relay are closed and the actual voltage across the first target relay is less than the target threshold, the controller sends a high level signal to the switch module corresponding to the first target relay to control the switch module to be turned on; A first resistor and a second resistor connected in series; the first resistor is used to access a first voltage, and the first resistor is connected to an end of the relay away from the switch module; A second transistor, the base of the second transistor is connected to the controller, the emitter of the second transistor is grounded, and the collector of the second transistor is connected to the second resistor; when the controller sends a high level signal to the second transistor, the second transistor is turned on.

6. The relay control circuit according to claim 5, characterized in that: The control module comprises: A third resistor is connected between the base of the second transistor and the controller.

7. The relay control circuit according to claim 5, characterized in that: Also includes: A PMOS tube, wherein the gate of the PMOS tube is connected between the first resistor and the second resistor connected in series, the source of the PMOS tube is used to connect to the first voltage, and the drain of the PMOS tube is respectively connected to one end of each of the relays away from the switch module; A diode, wherein the cathode of the diode is connected to the drain of the PMOS tube, and the anode of the diode is used to access a second voltage, wherein the second voltage is less than the first voltage; after the first target relay is closed, the controller sends a low-level signal to the second transistor, the PMOS tube is turned off, and the second voltage is accessed to the relay.

8. A control method based on the relay control circuit according to any one of claims 1 to 7, characterized in that: include: controlling the remaining relays of the at least one serially connected relay except the first target relay to close; Obtaining actual voltage across the first target relay; When the actual voltage is less than the target threshold, the first target relay is controlled to be closed.

9. The control method according to claim 8, characterized in that: When the actual voltage is less than the target threshold, after controlling the first target relay to close, the method further includes: The actual voltage across each of the relays is reduced.

10. The control method according to claim 8 or 9, characterized in that: Before controlling the remaining relays of the at least one serially connected relay except the first target relay to close, the method further includes: controlling a third target relay in the at least one serially connected relay to be closed; Acquiring the actual voltage across the third target relay; Based on the actual voltage, fault detection is performed on the third target relay.

11. An inverter system, characterized in that: include: An inverter circuit, the inverter circuit comprising at least one phase branch, the phase branch being provided with at least one relay connected in series; The relay control circuit according to any one of claims 1 to 7, wherein the relay control circuit is connected to the relay.

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