CN115184838A

CN115184838A - Relay short circuit failure detection method and device

Info

Publication number: CN115184838A
Application number: CN202211092109.3A
Authority: CN
Inventors: 伊晓光; 方湃盛
Original assignee: Shenzhen Yuntian Digital Energy Co ltd
Current assignee: Shenzhen Yuntian Digital Energy Co ltd
Priority date: 2022-09-08
Filing date: 2022-09-08
Publication date: 2022-10-14
Anticipated expiration: 2042-09-08
Also published as: CN115184838B

Abstract

The embodiment of the application discloses a method and a device for detecting short circuit failure of a relay, which comprise the following steps: by opening the first switch and the second switch; the driving module is used for controlling the main relay set and the auxiliary relay set to be disconnected; detecting a first inversion voltage and a first power grid voltage, and if a first difference absolute value of the first inversion voltage and the first power grid voltage is smaller than or equal to a first preset threshold value, determining that both the master relay group and the slave relay group have faults; otherwise, controlling the main relay group or the slave relay group to be alternately connected, detecting a second inversion voltage and a second power grid voltage, and determining that the main relay group or the slave relay group has a fault if the second difference absolute value is smaller than or equal to a first preset threshold value; otherwise, the first switch or the second switch is controlled to be alternately closed, and if the resistance voltage at the two ends of the first resistor or the second resistor is larger than a second preset threshold value, the target relay is determined to be in fault. Therefore, the fault relay can be accurately positioned, and the loss caused by the relay fault is reduced.

Description

Relay short circuit failure detection method and device

Technical Field

The application relates to the technical field of photovoltaic grid connection, in particular to a relay short circuit failure detection method and device.

Background

In an actual system, because grid-connected current is large, relay adhesion (namely, relay short-circuit phenomenon) caused by overcurrent easily occurs to a grid-connected inverter, and the short-circuit fault needs to be identified before the inverter is started. The present grid-connected inverter in the conventional technology only includes an inverter module, a power grid, and a relay group connected to the inverter module and the power grid. The existing identification detection method can only identify all the short-circuit faults of the main relay group and/or all the short-circuit faults of the slave relays by controlling the connection or disconnection of the main relay group and the slave relay group in the grid-connected inverter, but cannot specifically identify the fault reason of the short circuit of a single main relay or a single slave relay.

Therefore, a method for detecting a short circuit failure of a relay is needed to solve the above problems.

Disclosure of Invention

The embodiment of the application provides a relay short circuit failure detection method and device, and a failed relay group or a failed target relay is determined according to corresponding voltage changes through different relay access and switch closing modes. The fault relay can be accurately positioned so as to take countermeasures in time and reduce loss caused by relay fault.

In a first aspect, an embodiment of the present application provides a method for detecting a short circuit failure of a relay, which is applied to a photovoltaic grid-connected inverter system, where the photovoltaic grid-connected inverter system includes: the system comprises an inversion module, an inductance-capacitance module, a relay module, a switch module and a driving module; the inverter module comprises an input voltage and a switch tube group, wherein the input voltage is connected with the switch tube group in parallel, and the switch tube group comprises a switch tube Q1, a switch tube Q2, a switch tube Q3 and a switch tube Q4; a first port and a second port of the inductance-capacitance module are respectively connected with the switch tube Q1 and the switch tube Q4, a third port and a fourth port of the inductance-capacitance module are respectively connected with a first port and a second port of the relay module, and the relay module comprises a main relay group, a slave relay group and a power grid voltage which are arranged in series; the switch module comprises a first switch module and a second switch module, the first switch module and the second switch module are respectively connected in parallel to two sides of the relay module, the first switch module comprises a first switch and a first resistor which are arranged in series, and the second switch module comprises a second switch and a second resistor which are arranged in series; the driving module is used for controlling the relay module to be switched on or switched off;

the method comprises the following steps:

opening the first switch and the second switch;

controlling the main relay group and the slave relay group to be disconnected through the driving module, wherein the main relay group comprises a first main relay and a second main relay, and the slave relay group comprises a first slave relay and a second slave relay;

detecting a first inversion voltage and a first power grid voltage, and calculating a first difference absolute value of the first inversion voltage and the first power grid voltage;

if the first absolute difference value is smaller than or equal to a first preset threshold value, determining that the master relay set and the slave relay set both have faults;

otherwise, controlling the main relay group or the slave relay group to be alternately connected through the driving module, detecting a second inversion voltage and a second power grid voltage, and calculating a second difference absolute value of the second inversion voltage and the second power grid voltage;

if the second difference absolute value is smaller than or equal to the first preset threshold, determining that the main relay set or the slave relay set has a fault;

otherwise, controlling the first switch or the second switch to be alternately closed, and detecting the voltage at two ends of the first resistor or the second resistor to obtain the resistor voltage;

and if the resistance voltage is larger than a second preset threshold value, determining that the target relay has a fault.

In a second aspect, the device for detecting short circuit failure of a relay provided in an embodiment of the present application is applied to a photovoltaic grid-connected inverter system, where the photovoltaic grid-connected inverter system includes: the system comprises an inversion module, an inductance-capacitance module, a relay module, a switch module and a driving module; the inverter module comprises an input voltage and a switch tube group, wherein the input voltage is connected with the switch tube group in parallel, and the switch tube group comprises a switch tube Q1, a switch tube Q2, a switch tube Q3 and a switch tube Q4; a first port and a second port of the inductance-capacitance module are respectively connected with the switch tube Q1 and the switch tube Q4, a third port and a fourth port of the inductance-capacitance module are respectively connected with a first port and a second port of the relay module, and the relay module comprises a main relay group, a slave relay group and a power grid voltage which are arranged in series; the switch module comprises a first switch module and a second switch module, the first switch module and the second switch module are respectively connected in parallel to two sides of the relay module, the first switch module comprises a first switch and a first resistor which are arranged in series, and the second switch module comprises a second switch and a second resistor which are arranged in series; the driving module is used for controlling the relay module to be switched on or switched off;

the device comprises a control unit, a detection unit, a judgment unit and a determination unit;

the control unit is used for disconnecting the first switch and the second switch; the driving module is used for controlling the main relay group and the slave relay group to be disconnected, wherein the main relay group comprises a first main relay and a second main relay, and the slave relay group comprises a first slave relay and a second slave relay;

the detection unit is used for detecting a first inversion voltage and a first power grid voltage and calculating a first difference absolute value of the first inversion voltage and the first power grid voltage;

the judging unit is used for determining that the master relay set and the slave relay set both have faults if the first difference absolute value is smaller than or equal to a first preset threshold value;

otherwise, the control unit controls the main relay group or the slave relay group to be alternately connected through the driving module, detects a second inversion voltage and a second power grid voltage through the detection unit, and calculates a second difference absolute value of the second inversion voltage and the second power grid voltage;

the judging unit is further configured to determine that the master relay set or the slave relay set fails if the second difference absolute value is less than or equal to the first preset threshold;

otherwise, the control unit controls the first switch or the second switch to be alternately closed, and the voltage at two ends of the first resistor or the second resistor is detected by the detection unit to obtain the resistor voltage;

and the judging unit is also used for determining that the target relay has a fault if the resistance voltage is less than or equal to a second preset threshold value.

In a third aspect, an embodiment of the present application provides a relay short-circuit failure detection apparatus, which is applied to a photovoltaic grid-connected inverter system, where the photovoltaic grid-connected inverter system includes: the system comprises an inversion module, an inductance-capacitance module, a relay module, a switch module and a driving module; the inverter module comprises an input voltage and a switch tube group, wherein the input voltage is connected with the switch tube group in parallel, and the switch tube group comprises a switch tube Q1, a switch tube Q2, a switch tube Q3 and a switch tube Q4; a first port and a second port of the inductance-capacitance module are respectively connected with the switch tube Q1 and the switch tube Q4, a third port and a fourth port of the inductance-capacitance module are respectively connected with a first port and a second port of the relay module, and the relay module comprises a main relay group, a slave relay group and a power grid voltage which are arranged in series; the switch module comprises a first switch module and a second switch module, the first switch module and the second switch module are respectively connected in parallel to two sides of the relay module, the first switch module comprises a first switch and a first resistor which are arranged in series, and the second switch module comprises a second switch and a second resistor which are arranged in series; the driving module is used for controlling the relay module to be switched on or switched off;

the judging unit is used for determining that the main relay group and the slave relay group both have faults if the first difference absolute value is smaller than or equal to a first preset threshold value;

the judging unit is further configured to determine that the master relay set or the slave relay set has a fault if the second absolute difference value is smaller than or equal to the first preset threshold;

the judging unit is further used for determining that the target relay breaks down if the resistance voltage is smaller than or equal to a second preset threshold.

In a fourth aspect, the present embodiment provides an electronic device applied to a photovoltaic grid-connected inverter system, where the electronic device includes a processor, a memory, a communication interface, and one or more programs, where the one or more programs are stored in the memory and configured to be executed by the processor to perform some or all of the steps described in the method of the first aspect.

In a fifth aspect, the present invention provides a computer-readable storage medium storing a computer program for electronic data exchange, wherein the computer program causes a computer to perform some or all of the steps described in the method of the first aspect.

It can be seen that, the method for detecting the short circuit failure of the relay provided by the application comprises the steps of switching off a first switch and a second switch; the driving module is used for controlling the main relay group and the auxiliary relay group to be disconnected; detecting a first inversion voltage and a first power grid voltage, and if a first difference absolute value of the first inversion voltage and the first power grid voltage is less than or equal to a first preset threshold, determining that both the master relay group and the slave relay group have faults; otherwise, controlling the alternate connection of the main relay group or the slave relay group, detecting a second inversion voltage and a second power grid voltage, and determining that the main relay group or the slave relay group has a fault if a second difference absolute value is less than or equal to a first preset threshold value; otherwise, the first switch or the second switch is controlled to be alternately closed, and if the resistance voltage at the two ends of the first resistor or the second resistor is larger than a second preset threshold value, the target relay is determined to be in fault. Therefore, the fault relay can be accurately positioned, and the loss caused by the relay fault is reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic module diagram of a photovoltaic grid-connected system according to an embodiment of the present disclosure;

fig. 2 is a schematic circuit diagram of a method for detecting a short-circuit failure of a relay according to an embodiment of the present disclosure;

fig. 3 is a flowchart of a method for detecting a short-circuit failure of a relay according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of another relay short-circuit failure detection process provided in the embodiments of the present application;

fig. 5 is a schematic structural diagram of an electronic device provided in an embodiment of the present application;

fig. 6 is a block diagram of functional units of a relay short-circuit failure detection apparatus provided in an embodiment of the present application.

Detailed Description

In order to better understand the technical solutions of the present application, the following description is given for clarity and completeness in conjunction with the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some embodiments of the present application, but not all embodiments. All other embodiments obtained by a person skilled in the art without making any inventive step on the basis of the description of the embodiments of the present application belong to the protection scope of the present application.

The terms "first," "second," and the like in the description and claims of the present application and in the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, software, product, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements recited, but may also include other steps or elements not expressly listed or inherent to such process, method, product, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein may be combined with other embodiments.

The embodiments of the present application will be described with reference to the drawings, in which a dot at the intersection of intersecting wires indicates that the wires are connected, and a dot-free intersection indicates that the wires are not connected.

Referring to fig. 1, fig. 1 is a schematic block diagram of a photovoltaic grid-connected system according to an embodiment of the present disclosure. As shown in fig. 1, the pv grid-connected system 100 specifically includes an inverter module 110, an inductor-capacitor module 120, a relay module 130, a switch module 140, and a driving module 150, which are connected in sequence.

The inverter module comprises an input voltage and a switch tube group, wherein the input voltage is connected with the switch tube group in parallel, and the switch tube group comprises a switch tube Q1, a switch tube Q2, a switch tube Q3 and a switch tube Q4; a first port and a second port of the inductance-capacitance module are respectively connected with the switch tube Q1 and the switch tube Q4, a third port and a fourth port of the inductance-capacitance module are respectively connected with a first port and a second port of the relay module, and the relay module comprises a main relay group, a slave relay group and a power grid voltage which are arranged in series; the switch module comprises a first switch module and a second switch module, the first switch module and the second switch module are respectively connected in parallel to two sides of the relay module, the first switch module comprises a first switch and a first resistor which are arranged in series, and the second switch module comprises a second switch and a second resistor which are arranged in series; the driving module is used for controlling the relay module to be switched on or switched off.

For better understanding of the working principle of the photovoltaic grid-connected system described in fig. 1, please refer to fig. 2, and fig. 2 is a schematic circuit diagram of a relay short-circuit failure detection method according to an embodiment of the present application.

Fig. 2 shows a schematic circuit diagram of the relay short-circuit failure detection, in which the inverter module includes an input voltage Vin and a switch tube group. Specifically, the switch tube group includes a switch tube Q1, a switch tube Q2, a switch tube Q3, and a switch tube Q4. The first end of the input voltage Vin is connected with the drain electrode of the switch tube Q1 and the drain electrode of the switch tube Q3, the second end of the input voltage Vin is connected with the source electrode of the switch tube Q2 and the source electrode of the switch tube Q4, the source electrode of the switch tube Q1 is connected with the drain electrode of the switch tube Q2, and the source electrode of the switch tube Q3 is connected with the drain electrode of the switch tube Q4.

Illustratively, the inductor-capacitor module includes a resonant inductor and a capacitor C, and the resonant inductor includes a first resonant inductor L1 and a second resonant inductor L2. The source electrode of the switching tube Q1 is connected to the first end of the first resonant inductor L1, the second end of the first resonant inductor L1 is connected to one end of the capacitor C, the source electrode of the switching tube Q4 is connected to the first end of the second resonant inductor L2, and the second end of the capacitor C is connected to the second end of the second resonant inductor L2.

Exemplarily, the relay module includes a main relay group, a slave relay group and a Grid voltage Grid, wherein the main relay group, the Grid voltage Grid and the slave relay group are sequentially connected in series, and specifically, the main relay group includes a first main relay K1 and a second main relay K3, and the slave relay group includes a first slave relay K2, a second slave relay K4, and the first main relay K1, the Grid voltage Grid, the second main relay K3, the first slave relay K2 and the second slave relay K4 are sequentially connected.

Illustratively, the switch module includes a switch including a first switch S1 and a second switch S2 and a resistor including a first resistor R1 and a second resistor R2. The first end of the first switch S1 is connected with the first end of the first slave relay K2 in parallel, the second end of the first switch S1 is connected with the first end of the first resistor R1 in series, the second end of the first resistor R1 is connected with the second end of the first master relay K1 in parallel, the first end of the second switch S2 is connected with the first end of the second slave relay K4 in parallel, the second end of the second switch S2 is connected with the first end of the second resistor R2 in series, and the second end of the second resistor R2 is connected with the second end of the second master relay K3 in parallel.

In addition, it should be noted that the first switch S1 and the second switch S2 may be switches of any form, and the first resistor R1 and the second resistor R2 are not limited to a common resistor, and may also be a high-impedance circuit component, an inductor, or a capacitor.

Illustratively, the driving module controls the master relay set and the slave relay set to be switched in and switched out through driving signals, wherein the driving signals include a first driving signal and a second driving signal as shown in fig. 1, which are respectively used for controlling the master relay set and the slave relay set to be switched in and switched out.

It should be noted that, in the embodiment of the present application, the inverter module 110, the inductance-capacitance module 120, the relay module 130, the switch module 140, and the driving module 150 in the photovoltaic grid-connected system 100 may be completed by a hardware integrated logic circuit, or may be completed by an instruction in a software form, or may be completed by a combination of hardware and a software unit, which is not limited in this application.

Referring to fig. 3, fig. 3 is a flowchart of a method for detecting a short-circuit failure of a relay according to an embodiment of the present disclosure.

S301, disconnecting the first switch and the second switch.

S302, the driving module controls the main relay group and the auxiliary relay group to be disconnected.

The master relay group comprises a first master relay and a second master relay, and the slave relay group comprises a first slave relay and a second slave relay.

Specifically, the driving module transmits a first driving signal drive1 and a second driving signal drive2 to the master relay group and the slave relay group. The first driving signal comprises a first connection driving signal and a first disconnection driving signal, and the second driving signal comprises a second connection driving signal and a second disconnection driving signal. Specifically, the first connection driving signal and the second connection driving signal are realized by setting drive1 and drive2 to a high level state, and the first disconnection driving signal and the second disconnection driving signal are realized by setting drive1 and drive2 to a zero level state.

Exemplarily, if the current driving module needs to control the connection between the master relay set and the slave relay set, the drive1 and the drive2 are set to be in a high level state; and if the current driving module needs to control the main relay group to be disconnected with the auxiliary relay group, setting drive1 and drive2 to be in a zero level state.

S303, detecting a first inversion voltage and a first power grid voltage, and calculating a first difference absolute value of the first inversion voltage and the first power grid voltage.

Specifically, a voltage value Uva at the side of the inverter is detected to obtain a first inverter voltage, and a voltage value Usa at two ends of the grid voltage is detected to obtain the first grid voltage.

Further, a first absolute value of the difference between the first inverted voltage and the first grid voltage is calculated.

S304, if the absolute value of the first difference is smaller than or equal to a first preset threshold value, it is determined that both the main relay group and the slave relay group have faults.

Specifically, when the first inversion voltage is close to the first power grid voltage, the current relay failure detection circuit can be determined to be a through circuit, and at the moment, it is determined that both the main relay group and the slave relay group have adhesion faults, namely, the main relay group and the slave relay group have short-circuit phenomena.

For example, the first preset threshold may be set according to actual situations, for example: any value between 1V and 3V, or a default value may be set according to the safety standard rule, which is not specifically limited herein.

Further, if it is determined that all the current relay groups have faults, the inverter stops working, and fault reporting is performed.

And S305, otherwise, controlling the main relay group or the slave relay group to be alternately connected through the driving module, detecting a second inversion voltage and a second power grid voltage, and calculating a second difference absolute value of the second inversion voltage and the second power grid voltage.

Illustratively, when the first absolute difference value is greater than a first preset threshold, the main relay group and the slave relay group are alternately switched in, the inversion side voltage Uva and the grid voltage Usa under the condition of two-time switching-in are respectively detected, and the absolute difference value of the inversion side voltage Uva and the grid voltage Usa is calculated.

Further, whether the main relay set or the slave relay set fails or not is determined according to a comparison result between the absolute value of the difference calculated each time and a first preset threshold.

Illustratively, the driving module controls the connection and disconnection of the main relay set and the auxiliary relay set by setting drive1 to be at a high level and setting drive2 to be at a zero level. And detecting the voltage of the inversion side and the voltage of the power grid to obtain a second difference absolute value, and comparing the magnitude relation between the second difference absolute value and a first preset threshold value.

S306, if the second difference absolute value is smaller than or equal to the first preset threshold, determining that the main relay set or the slave relay set has a fault.

For example, if the second absolute difference value is smaller than or equal to the first preset threshold, it indicates that the circuit is still on when the master relay set is connected and the slave relay set is disconnected, that is, the slave relay set has a stuck fault, resulting in the circuit being turned on. Therefore, it is determined that the short-circuit fault has occurred from the relay group.

Further, the inverter stops working, and reports that the slave relay group has a fault.

S307, otherwise, controlling the first switch or the second switch to be closed alternately, and detecting the voltage at two ends of the first resistor or the second resistor to obtain the resistor voltage.

And S308, if the resistance voltage is larger than a second preset threshold value, determining that the target relay has a fault.

Specifically, if the absolute value of the second difference is greater than the first preset threshold, the first switch or the second switch is controlled to be closed, and at this time, the first resistor or the second resistor is connected to the circuit.

Illustratively, when the main relay group is closed and the auxiliary relay group is opened, and the first switch is closed and the second switch is opened, the voltage value at two ends of the first resistor is detected to obtain the voltage of the first resistor.

And further, comparing the first resistance voltage with a second preset threshold, and if the first resistance voltage is greater than the second preset threshold, determining that the current second slave relay is connected to form a complete loop. Thereby determining that the second slave relay has the sticking fault.

Further, the inverter stops working, and reports that the second slave relay has faults.

If the voltage of the current first resistor is far smaller than a second preset threshold value, it is indicated that the first resistor is not connected to the circuit, and then the second slave relay has an adhesion fault. At the moment, the first switch is controlled to be opened, the second switch is controlled to be closed, and the voltage values at two ends of the second resistor are detected to obtain the voltage of the second resistor.

And further, determining whether the first slave relay has the adhesion fault according to the comparison result of the second resistance voltage and a second preset threshold value.

It should be noted that the process of determining whether the first main relay or the second main relay has the adhesion fault is similar to the above method, and redundant description is not repeated herein.

It can be seen that, in the embodiment of the present application, by turning off the first switch and the second switch; the driving module is used for controlling the main relay set and the auxiliary relay set to be disconnected; detecting a first inversion voltage and a first power grid voltage, and if a first difference absolute value of the first inversion voltage and the first power grid voltage is less than or equal to a first preset threshold, determining that both the master relay group and the slave relay group have faults; otherwise, controlling the alternate connection of the main relay group or the slave relay group, detecting a second inversion voltage and a second power grid voltage, and determining that the main relay group or the slave relay group has a fault if a second difference absolute value is less than or equal to a first preset threshold value; otherwise, the first switch or the second switch is controlled to be alternately closed, and if the resistance voltage at the two ends of the first resistor or the second resistor is larger than a second preset threshold value, the target relay is determined to be in fault. Therefore, the fault relay can be accurately positioned, and the loss caused by the relay fault is reduced.

In a possible embodiment, before the driving module controls the master relay set or the slave relay sets to be alternately connected, the method further includes the following steps: if the first absolute difference value is greater than the first preset threshold, adjusting the first inverter voltage by the inverter module to perform phase-locking wave-sending so that the first inverter voltage is equal to the first grid voltage, where the phase-locking wave-sending is that the inverter module performs phase-locking operation through hardware or software to adjust the first inverter voltage.

Specifically, in step S305, if the absolute value of the current first difference is greater than the first preset threshold, it indicates that there is a large difference between the voltage value of the inverter side and the voltage value of the power grid, and at this time, if the grid-connected operation is directly performed, a relay fault is easily caused. Therefore, before the master relay set or the slave relay set is connected, the voltage on the inverting side needs to be adjusted so that the first grid voltage and the first inverting voltage are equal.

Illustratively, the first inverter voltage is adjusted in a phase-locked wave-sending mode, and after the phase of the first inverter voltage is consistent with the phase of the first grid voltage, the phase-locked wave-sending is stopped.

Further, when the first inversion voltage is consistent with the first power grid voltage, the first inversion voltage is connected to the main relay set or the auxiliary relay set to perform the next fault detection process.

It should be noted that, the phase-locked wave-sending operation may be performed by performing phase adjustment on the first inverted voltage through a software method, or may be performed through hardware, and is not limited specifically herein.

Therefore, the inverter side voltage is adjusted in a phase-locked wave-sending mode, so that when the relay set is connected into the circuit, the grid-connected voltage is consistent with the phase of the power grid voltage, and the relay can be smoothly connected to avoid the phenomenon that the relay is damaged by overcurrent.

In a possible embodiment, the driving module controls the master relay set and the slave relay set to be disconnected, and the method specifically includes the following steps: through drive module to main relay group sends first drive signal, to from relay group sends second drive signal, wherein, first drive signal is used for control main relay group connects or breaks off, second drive signal is used for control from relay group connects or breaks off, first drive signal includes first connection drive signal and first disconnection drive signal, second drive signal includes second connection drive signal and second disconnection drive signal.

Illustratively, as described in step S302, the driving module controls the connection and disconnection of the master relay set and the slave relay set through drive1 and drive2. If the master relay set is to be accessed and the slave relay set is disconnected at present, only a first driving signal needs to be sent to the master relay set, and drive1 is in a high level state; and sending a second driving signal to the slave relay group, wherein drive2 is in a zero level state.

It can be seen that, in the embodiment of the present application, the driving module controls the access and the disconnection of the master relay group and the slave relay group respectively through the first driving signal and the second driving signal, and the first master relay and the second master relay in the master relay group, the first slave relay and the second slave relay in the slave relay group respectively share the corresponding driving control signal, and the driving signal corresponding to the same relay group realizes the on-off of the switch through the control level state, so that the flexible control of the relays can be realized.

In a possible embodiment, the determining that the master relay set or the slave relay set is faulty specifically includes the following steps: sending the first connection driving signal to the main relay group through the driving module, and detecting the second inversion voltage and the second power grid voltage; calculating the second absolute difference value between the second inversion voltage and the second power grid voltage, and if the second absolute difference value is smaller than or equal to the first preset threshold, determining that the slave relay group sends a fault; or the second connection driving signal is sent to the slave relay group through the driving module, and a third inversion voltage and a third power grid voltage are detected; and calculating a third difference absolute value of the third inversion voltage and the third power grid voltage, and determining that the main relay group breaks down if the third difference absolute value is less than or equal to the first preset threshold.

Specifically, as shown in steps S305 to S306, the driving module controls the access circuit of the master relay set by sending a first connection driving signal, i.e., drive1, to the master relay set to be in a high level state and sending a second disconnection driving signal, i.e., drive2, to the slave relay set to be in a zero level state.

Further, the inverter side voltage Uva and the grid voltage Usa are detected to obtain a second inversion voltage and a second grid voltage, the absolute value of the difference between the second inversion voltage and the second grid voltage is calculated, and whether the slave relay group is abnormal or not is determined according to the magnitude relation between the second absolute value of the difference and the first preset threshold.

For example, if the second absolute difference value is smaller than or equal to the first preset threshold, it indicates that the measured inverter-side voltage Uva and the grid voltage Usa are close to each other, i.e., the current circuit belongs to the on state. However, the connection state of the current circuit indicates that the entire circuit is in the off state because the slave relay group is not connected. Therefore, when the absolute value of the second difference is smaller than or equal to the first preset threshold, it can be determined that the slave relay set is in fault adhesion, so that the circuit is turned on.

Similarly, the drive module can send a drive2 setting high level state as a second connection drive signal to the slave relay set, and send a drive1 voltage setting zero level state as a first disconnection drive signal to the master relay set. And repeating the voltage detection and calculation processes to determine whether the main relay group has faults. Will not be described in detail herein.

Further, if the current main relay group or the current slave relay group is determined to be in fault, the inverter stops working, and fault reporting is executed.

It can be seen that, in the embodiment of the present application, different driving signals sent by the driving module are used to alternately access the main relay group or the slave relay group, and the relay group with a fault is determined through voltage measurement and calculation, so that the fault position is quickly determined and the fault reporting is completed.

In a possible embodiment, the method specifically further includes the following steps: if the second absolute difference value is larger than the first preset threshold, the second inversion voltage is adjusted through the inversion module in a phase-locked wave-transmitting mode, so that the second inversion voltage is equal to the second power grid voltage; controlling the first switch to be closed and the second switch to be opened, and detecting first voltages on two sides of the first resistor; if the first voltage is larger than the second preset threshold value, determining that the second slave relay has a fault; otherwise, controlling the second switch to be closed and the first switch to be opened, and detecting second voltages at two sides of the second resistor; and if the second voltage is greater than the second preset threshold value, determining that the first slave relay has a fault.

Specifically, when the master relay unit is connected and the slave relay unit is disconnected, if the absolute value of the second difference is greater than the first preset threshold, it is indicated that the difference between the second inverter voltage and the second grid voltage is large, at this time, the phase of the second inverter voltage is adjusted through the phase-locked wave-transmitting operation, and the phase-locked wave-transmitting operation is stopped until the amplitude of the second inverter voltage is consistent with the amplitude of the second grid voltage.

Further, the first switch is controlled to be closed, the second switch is controlled to be opened, the voltage Ur on the two sides of the first resistor R1 is detected, the voltage Ur is compared with a second preset threshold value Uset, if the voltage Ur is larger than the threshold value Uset, it is indicated that voltage passes through the first resistor R1 at the moment, namely a current circuit forms a loop state, according to a circuit diagram shown in fig. 2, if current passes through the first resistor R1, it is indicated that the second slave relay, namely K4, is adhered, and therefore the second slave relay fault is determined.

In another possible example, the second switch is controlled to be closed, the first switch is controlled to be open, the voltage Ur at two sides of the second resistor R2 is detected, the voltage Ur is compared with a second preset threshold value Uset, if the voltage Ur is greater than the threshold value Uset, it is indicated that voltage passes through the second resistor R2 at the moment, namely, a current circuit forms a loop state, and according to a circuit diagram shown in fig. 2, if current passes through R2, it is indicated that the first slave relay, namely K2, is stuck, so that the fault of the first slave relay is determined.

Further, when the target slave relay with the fault is determined to be the first slave relay or the second slave relay, the relay stops working, and the fault of the target slave relay is reported.

It should be noted that the switches and the resistors mentioned in this application are switches and resistors set for easy understanding, in an actual scenario, the first switch S1 and the second switch S2 may be switches of any form, and the first resistor R1 and the second resistor R2 are not limited to a common resistor, and may also be a high-impedance circuit component, an inductor, a capacitor, or the like, and are not limited specifically herein.

It can be seen that, in the embodiment of the application, under the condition that the main relay group is switched in and the slave relay group is switched off, the S1 or the S2 is alternately closed, the voltage at the two ends of the resistor R1 or the R2 is detected, and then the voltage is compared with the second preset threshold value Uset, so that the target slave relay with the fault is determined, and the fault reporting is completed.

In a possible embodiment, the method specifically further includes the following steps: if the absolute value of the third difference is greater than the first preset threshold, the third inversion voltage is adjusted through the inversion module to perform phase-locked wave sending, so that the third inversion voltage is equal to the third power grid voltage; controlling the first switch to be closed and the first switch to be opened, and detecting a third voltage on two sides of the first resistor; if the third voltage is larger than the second preset threshold value, determining that the second main relay has a fault; otherwise, controlling the second switch to be closed and the first switch to be opened, and detecting fourth voltages at two sides of the second resistor; and if the fourth voltage is greater than the second preset threshold value, determining that the first main relay has a fault.

Specifically, when the slave relay set is switched in and the master relay set is switched off, if the absolute value of the third difference is greater than the first preset threshold, it indicates that the difference between the third inverter voltage and the third grid voltage is large, at this time, the phase of the third inverter voltage is adjusted through the phase-locked wave-sending operation, and the phase-locked wave-sending operation is stopped until the amplitude of the third inverter voltage is consistent with the amplitude of the third grid voltage.

Further, the first switch is controlled to be closed, the second switch is controlled to be opened, the voltage Ur on the two sides of the first resistor R1 is detected, the Ur is compared with a second preset threshold value Uset, if the Ur is larger than the Uset, it is indicated that the voltage passes through the first resistor R1 at the moment, namely, a current circuit forms a loop state, according to a circuit diagram shown in fig. 2, if the current passes through the R1, it is indicated that the second main relay, namely K3, is adhered, and therefore the fault of the second main relay is determined.

In another possible example, the second switch is controlled to be closed, the first switch is controlled to be open, the voltage Ur at two sides of the second resistor R2 is detected, the Ur is compared with a second preset threshold value Uset, if the Ur is larger than the Uset, it is indicated that voltage passes through the second resistor R2 at the moment, namely, a current circuit forms a loop state, and according to a circuit diagram shown in fig. 2, if current passes through R2, it is indicated that the first main relay, namely K1, is stuck, so that the first main relay fault is determined.

Further, when the target main relay with the fault is determined to be the first main relay or the second main relay, the relay stops working, and the fault of the target main relay is reported.

It can be seen that, in the embodiment of the present application, when the slave relay group is switched in and the master relay group is switched off, the S1 or S2 is alternately closed, and after the voltage Ur at the two ends of the resistor R1 or R2 is detected, the voltage Ur is compared with the second preset threshold Uset, so as to determine the target master relay that has a fault and complete fault reporting.

In order to better understand the relay fault detection process of the present application, the detection process of the present application will be described in the following with reference to fig. 4. Fig. 4 is a schematic flowchart of another relay short-circuit failure detection provided in the embodiment of the present application. The method specifically comprises the following steps:

s401, disconnecting S1 and S2, and the master relay set and the slave relay set.

S402, detecting the first inversion voltage and the first power grid voltage.

And S403, calculating a first difference absolute value.

S404, judging whether the absolute value of the first difference is smaller than or equal to a first preset threshold value.

And S405, if yes, determining that the main relay group and the slave relay group both have faults.

And S406, if not, alternately accessing the main relay group or the slave relay group.

And S407, detecting the second inversion voltage and the second power grid voltage.

And S408, calculating a second difference absolute value.

And S409, judging whether the absolute value of the second difference is less than or equal to a first preset threshold value.

And S410, if yes, determining that the main relay group or the slave relay group has a fault.

And S411, if not, alternately accessing S1 or S2.

S412, detecting the voltage value Ur of the first resistor R1 or the second resistor R2.

S413, judging whether Ur is larger than a second preset threshold value Uset.

And S414, if yes, determining that the target relay is in fault.

And S415, if not, continuing the operation of the inverter.

All the steps S401 to S415 may correspond to the steps S301 to S308, and will not be described in detail here.

It can be seen that, the method for detecting the short circuit failure of the relay provided by the application comprises the steps of switching off a first switch and a second switch; the driving module is used for controlling the main relay set and the auxiliary relay set to be disconnected; detecting a first inversion voltage and a first power grid voltage, and if a first difference absolute value of the first inversion voltage and the first power grid voltage is less than or equal to a first preset threshold, determining that both the master relay group and the slave relay group have faults; otherwise, controlling the main relay group or the slave relay group to be alternately connected, detecting a second inversion voltage and a second power grid voltage, and determining that the main relay group or the slave relay group has a fault if the second difference absolute value is smaller than or equal to a first preset threshold value; otherwise, the first switch or the second switch is controlled to be alternately closed, and if the resistance voltage at the two ends of the first resistor or the second resistor is larger than a second preset threshold value, the target relay is determined to be in fault. Therefore, the fault relay can be accurately positioned, and loss caused by relay fault is reduced.

Referring to fig. 5, fig. 5 is a schematic structural diagram of an electronic device provided in an embodiment of the present application, and as shown in fig. 5, the electronic device is applied to a photovoltaic grid-connected inverter system, and includes a processor, a memory, a communication interface, and one or more programs, where the one or more programs are stored in the memory and configured to be executed by the processor, and the program includes instructions for executing all the method steps described in the embodiment of the present application.

The above description has introduced the solution of the embodiment of the present application mainly from the perspective of the method-side implementation process. It is understood that in order to implement the above functions, it includes corresponding hardware structures and/or software modules for performing the respective functions. Those of skill in the art will readily appreciate that the present application is capable of hardware or a combination of hardware and computer software implementing the various illustrative elements and algorithm steps described in connection with the embodiments provided herein. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiment of the present application, the functional units may be divided according to the above method examples, for example, each functional unit may be divided corresponding to each function, or two or more functions may be integrated into one processing unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit. It should be noted that, in the embodiment of the present application, the division of the unit is schematic, and is only one logic function division, and when the actual implementation is realized, another division manner may be provided.

Referring to fig. 6, fig. 6 is a block diagram of functional units of a relay short-circuit failure detection apparatus provided in an embodiment of the present application, and the block diagram is applied to a photovoltaic grid-connected inverter system, where the photovoltaic grid-connected inverter system includes: the system comprises an inversion module, an inductance-capacitance module, a relay module, a switch module and a driving module; the inverter module comprises an input voltage and a switch tube group, wherein the input voltage is connected with the switch tube group in parallel, and the switch tube group comprises a switch tube Q1, a switch tube Q2, a switch tube Q3 and a switch tube Q4; a first port and a second port of the inductance-capacitance module are respectively connected with the switch tube Q1 and the switch tube Q4, a third port and a fourth port of the inductance-capacitance module are respectively connected with a first port and a second port of the relay module, and the relay module comprises a main relay group, a slave relay group and a power grid voltage which are arranged in series; the switch module comprises a first switch module and a second switch module, the first switch module and the second switch module are respectively connected in parallel to two sides of the relay module, the first switch module comprises a first switch and a first resistor which are arranged in series, and the second switch module comprises a second switch and a second resistor which are arranged in series; the driving module is used for controlling the relay module to be switched on or switched off;

the device comprises a control unit 601, a detection unit 602 and a judgment unit 603;

the control unit 601 is configured to turn off the first switch and the second switch; the driving module is used for controlling the main relay group and the slave relay group to be disconnected, wherein the main relay group comprises a first main relay and a second main relay, and the slave relay group comprises a first slave relay and a second slave relay;

the detecting unit 602 is configured to detect a first inverter voltage and a first grid voltage, and calculate a first absolute difference value between the first inverter voltage and the first grid voltage;

the determining unit 603 is configured to determine that both the master relay group and the slave relay group have a fault if the first absolute difference value is smaller than or equal to a first preset threshold;

otherwise, the control unit 601 controls the main relay group or the slave relay group to be alternately connected through the driving module, detects a second inversion voltage and a second grid voltage through the detection unit 602, and calculates a second difference absolute value between the second inversion voltage and the second grid voltage;

the determining unit 603 is further configured to determine that the master relay set or the slave relay set fails if the second absolute difference value is smaller than or equal to the first preset threshold;

otherwise, the control unit 601 controls the first switch or the second switch to be alternately closed, and detects the voltage at two ends of the first resistor or the second resistor through the detection unit to obtain a resistor voltage;

the determining unit 603 is further configured to determine that the target relay fails if the resistance voltage is less than or equal to a second preset threshold.

It can be seen that, in the embodiment of the present application, the first switch and the second switch are turned off by the control unit; the driving module is used for controlling the main relay group and the slave relay group to be disconnected, wherein the main relay group comprises a first main relay and a second main relay, and the slave relay group comprises a first slave relay and a second slave relay; the detection unit detects the first inversion voltage and the first power grid voltage, and calculates a first difference absolute value of the first inversion voltage and the first power grid voltage; if the first difference absolute value is smaller than or equal to a first preset threshold, the judging unit is used for determining that the main relay set and the slave relay set both have faults; otherwise, the control unit controls the main relay group or the auxiliary relay group to be alternately connected through the driving module, detects the second inversion voltage and the second power grid voltage through the detection unit, and calculates a second difference absolute value of the second inversion voltage and the second power grid voltage; if the second absolute difference value is smaller than or equal to the first preset threshold, the judging unit is further used for determining that the main relay group or the slave relay group has a fault; otherwise, the control unit controls the first switch or the second switch to be alternately closed, and the voltage at the two ends of the first resistor or the second resistor is detected by the detection unit to obtain the resistor voltage; and if the resistance voltage is less than or equal to the second preset threshold, the judging unit is also used for determining that the target relay has a fault. So, through can realizing accurate positioning trouble relay, reduce the loss because of the relay trouble causes.

Embodiments of the present application also provide a computer storage medium, wherein the computer storage medium stores a computer program for electronic data exchange, and the computer program enables a computer to execute part or all of the steps of any one of the methods as described in the above method embodiments.

Embodiments of the present application also provide a computer program product comprising a non-transitory computer readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps of any one of the methods as set out in the above method embodiments. The computer program product may be a software installation package.

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

In the several embodiments provided in the present application, it should be understood that the disclosed relay short-circuit failure detection circuit may be implemented in other manners. For example, the above-described embodiment of the relay short circuit failure detection circuit is only illustrative, and for example, the components in the above-described circuit may also adopt other components with the same functions. In addition, the shown or discussed coupling or direct coupling or communication connection between each other may be an indirect coupling or communication connection through some interfaces, circuits or components, and may be electrical or in other forms.

In addition, each circuit in the embodiments of the present application may be integrated in one circuit board, or each circuit may exist alone, or two or more circuits may be integrated in one circuit board.

The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application with specific examples, and the above description of the embodiments is only provided to help understand the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, the specific embodiments and the application range may be changed, and in view of the above, the content of the present specification should not be construed as limiting the present application.

Claims

1. The method for detecting the short circuit failure of the relay is characterized by being applied to a photovoltaic grid-connected inverter system, wherein the photovoltaic grid-connected inverter system comprises the following steps: the system comprises an inversion module, an inductance-capacitance module, a relay module, a switch module and a driving module; the inverter module comprises an input voltage and a switch tube group, wherein the input voltage is connected with the switch tube group in parallel, and the switch tube group comprises a switch tube Q1, a switch tube Q2, a switch tube Q3 and a switch tube Q4; a first port and a second port of the inductance-capacitance module are respectively connected with the switch tube Q1 and the switch tube Q4, a third port and a fourth port of the inductance-capacitance module are respectively connected with a first port and a second port of the relay module, and the relay module comprises a main relay group, a slave relay group and a power grid voltage which are arranged in series; the switch module comprises a first switch module and a second switch module, the first switch module and the second switch module are respectively connected in parallel to two sides of the relay module, the first switch module comprises a first switch and a first resistor which are arranged in series, and the second switch module comprises a second switch and a second resistor which are arranged in series; the driving module is used for controlling the relay module to be switched on or switched off;

the method comprises the following steps:

opening the first switch and the second switch;

if the first difference absolute value is smaller than or equal to a first preset threshold value, determining that both the main relay group and the slave relay group have faults;

otherwise, the driving module controls the main relay group or the slave relay group to be alternately connected, detects a second inversion voltage and a second power grid voltage, and calculates a second difference absolute value of the second inversion voltage and the second power grid voltage;

if the second absolute difference value is smaller than or equal to the first preset threshold, determining that the main relay group or the slave relay group has a fault;

otherwise, controlling the first switch or the second switch to be closed alternately, and detecting the voltage at two ends of the first resistor or the second resistor to obtain a resistor voltage;

2. The method of claim 1, wherein prior to the controlling the master relay set or the slave relay sets to alternately connect by the driving module, the method further comprises:

if the first absolute difference value is greater than the first preset threshold, adjusting the first inversion voltage through the inversion module to perform phase-locking wave sending so that the first inversion voltage is equal to the first power grid voltage, wherein the phase-locking wave sending means that the inversion module performs phase-locking operation through hardware or software to achieve adjustment of the first inversion voltage.

3. The method of claim 1, wherein the controlling the master relay set and the slave relay set to be disconnected by the drive module comprises:

through drive module to main relay group sends first drive signal, to from relay group sends second drive signal, wherein, first drive signal is used for control main relay group connects or breaks off, second drive signal is used for control from relay group connects or breaks off, first drive signal includes first connection drive signal and first disconnection drive signal, second drive signal includes second connection drive signal and second disconnection drive signal.

4. The method of claim 3, wherein the determining that the master relay set or the slave relay set is faulty comprises:

sending the first connection driving signal to the main relay group through the driving module, and detecting the second inversion voltage and the second power grid voltage;

calculating the second absolute difference value between the second inversion voltage and the second power grid voltage, and if the second absolute difference value is smaller than or equal to the first preset threshold, determining that the slave relay group sends a fault; alternatively, the first and second electrodes may be,

sending the second connection driving signal to the slave relay group through the driving module, and detecting a third inversion voltage and a third power grid voltage;

and calculating a third difference absolute value of the third inversion voltage and the third power grid voltage, and determining that the main relay group breaks down if the third difference absolute value is less than or equal to the first preset threshold.

5. The method of claim 4, further comprising:

if the second difference absolute value is larger than the first preset threshold, the second inversion voltage is adjusted through the inversion module phase-locking wave-sending, so that the second inversion voltage is equal to the second power grid voltage;

controlling the first switch to be closed and the second switch to be opened, and detecting first voltages on two sides of the first resistor;

if the first voltage is larger than the second preset threshold value, determining that the second slave relay has a fault;

otherwise, controlling the second switch to be closed and the first switch to be opened, and detecting second voltages at two sides of the second resistor;

and if the second voltage is greater than the second preset threshold value, determining that the first slave relay has a fault.

6. The method of claim 4, further comprising:

if the third absolute difference value is greater than the first preset threshold, the third inversion voltage is adjusted through the inversion module to perform phase-locking wave-sending so that the third inversion voltage is equal to the third power grid voltage;

controlling the first switch to be closed and the second switch to be opened, and detecting a third voltage on two sides of the first resistor;

if the third voltage is greater than the second preset threshold, determining that the second main relay has a fault;

otherwise, controlling the second switch to be closed and the first switch to be opened, and detecting fourth voltage at two sides of the second resistor;

and if the fourth voltage is greater than the second preset threshold, determining that the first main relay has a fault.

7. The utility model provides a relay short circuit failure detection device which characterized in that is applied to photovoltaic grid-connected inverter system, photovoltaic grid-connected inverter system includes: the system comprises an inversion module, an inductance-capacitance module, a relay module, a switch module and a driving module; the inverter module comprises an input voltage and a switch tube group, wherein the input voltage is connected with the switch tube group in parallel, and the switch tube group comprises a switch tube Q1, a switch tube Q2, a switch tube Q3 and a switch tube Q4; a first port and a second port of the inductance-capacitance module are respectively connected with the switch tube Q1 and the switch tube Q4, a third port and a fourth port of the inductance-capacitance module are respectively connected with a first port and a second port of the relay module, and the relay module comprises a main relay group, a slave relay group and a power grid voltage which are arranged in series; the switch module comprises a first switch module and a second switch module, the first switch module and the second switch module are respectively connected in parallel to two sides of the relay module, the first switch module comprises a first switch and a first resistor which are arranged in series, and the second switch module comprises a second switch and a second resistor which are arranged in series; the driving module is used for controlling the relay module to be switched on or switched off;

the device comprises a control unit, a detection unit and a judgment unit;

otherwise, the control unit controls the main relay group or the slave relay group to be alternately connected through the driving module, detects a second inversion voltage and a second power grid voltage through the detection unit, and calculates a second difference absolute value between the second inversion voltage and the second power grid voltage;

otherwise, the control unit controls the first switch or the second switch to be alternately closed, and detects the voltage at two ends of the first resistor or the second resistor through the detection unit to obtain the resistor voltage;

8. The apparatus of claim 7, further comprising: and the phase locking unit is used for adjusting the first inversion voltage through phase locking wave sending of the inversion module if the first difference absolute value is greater than the preset threshold value, so that the first inversion voltage is equal to the first power grid voltage, wherein the phase locking wave sending means that the inversion module performs phase locking operation through hardware or software to realize adjustment of the first inversion voltage.

9. An electronic device, characterized in that it is applied to a photovoltaic grid-connected inverter system, comprising a processor, a memory, a communication interface, and one or more programs, stored in said memory and configured to be executed by said processor, said programs comprising steps for carrying out the method according to any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program for electronic data exchange, wherein the computer program causes a computer to perform the steps of the method according to any one of claims 1-6.