Relay protection circuit and ups

Abstract

The application discloses a relay protection circuit and a UPS, which are applied to the technical field of circuits and comprise a relay including a control coil and a contact group, the contact group being connected with a first direct-current power supply and a direct-current conversion circuit; a relay driving circuit connected with the control coil; a coil detection circuit, which is used for outputting first and second fault signals to a controller and a hardware driving locking circuit respectively when detecting that the control coil is in an abnormal working state; the hardware driving locking circuit, which is used for adjusting a circuit state of the hardware driving locking circuit to switch the direct-current conversion driving circuit to a non-working state when receiving the second fault signal; the controller, which is used for controlling the direct-current conversion driving circuit to be switched to the non-working state when receiving the first fault signal; a direct-current conversion circuit; and a direct-current conversion driving circuit connected with the direct-current conversion circuit. The scheme of the application can effectively avoid the situation that the relay is directly disconnected, and the reliability of the circuit is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit, in particular to a relay protection circuit and UPS. BACKGROUND

[0002] At present, when designing the UPS (Uninterruptible Power Supply), the requirement for efficiency is higher and higher. Therefore, in the UPS topology, in order to reduce the loss of thyristor power device, using the relay to replace the thyristor as the loop switch control device gradually becomes the mainstream at present.

[0003] The relay has the advantages of low loss, simple driving circuit, small space size, etc. However, when the relay breaks the direct current, there will be a serious arc problem, and the contact damage, sticking, impedance increase and serious heating will occur, and even the single board device will be damaged.

[0004] At present, when the UPS works under load, if the underground power is normal, the boost circuit drive will be turned off first, so that the relay loop has no current when the relay is turned off, that is, the relay direct current breaking will not occur. But in abnormal conditions, that is, when the relay related line or the relay itself is abnormal, the relay contact will break with current, produce arc, and then cause the above-mentioned contact damage, sticking, damage to single board device and other consequences.

[0005] In summary, how to effectively avoid the relay direct current breaking and ensure the reliability of the circuit is a technical problem that needs to be solved by the technical personnel in the field at present. SUMMARY

[0006] The purpose of the present application is to provide a relay protection circuit and UPS, which can effectively avoid the relay direct current breaking and ensure the reliability of the circuit.

[0007] To solve the above technical problems, the present application provides the following technical solutions:

[0008] A relay protection circuit, comprising:

[0009] A relay comprising a control coil and a contact group, a first end of the contact group being connected with a first direct current power supply, and a second end of the contact group being connected with a direct current conversion circuit;

[0010] A relay driving circuit connected with the control coil, used for driving control of the control coil under the control of a controller;

[0011] a coil detection circuit, configured to output a first fault signal to the controller and a second fault signal to a hardware drive lockout circuit when the control coil is detected to be in an abnormal working state;

[0012] the hardware drive lockout circuit connected with the DC conversion driving circuit, configured to adjust its circuit state to switch the DC conversion driving circuit to a non-working state when the second fault signal is received;

[0013] the controller connected with the DC conversion driving circuit, configured to control the DC conversion driving circuit to switch to a non-working state when the first fault signal is received;

[0014] the DC conversion circuit;

[0015] the DC conversion driving circuit connected with the DC conversion circuit, configured to perform driving control of the DC conversion circuit.

[0016] Preferably, the coil detection circuit comprises: a current detection circuit configured to detect whether the coil current of the control coil is abnormal; and a voltage detection circuit configured to detect whether the coil voltage of the control coil is abnormal.

[0017] The coil detection circuit is specifically configured to:

[0018] when the current detection circuit detects that the coil current is abnormal, or when the voltage detection circuit detects that the coil voltage is abnormal, it is determined that the control coil is in an abnormal working state, a first fault signal is output to the controller, and a second fault signal is output to the hardware drive lockout circuit.

[0019] Preferably, the voltage detection circuit comprises:

[0020] a first resistor with a first end connected with a first detection end of the voltage detection circuit and a second end connected with a positive input end of a first operational amplifier and a second end connected with a first end of a third resistor;

[0021] a second resistor with a first end connected with a second detection end of the voltage detection circuit and a second end connected with a negative input end of the first operational amplifier and a first end of the third resistor;

[0022] the third resistor with a second end connected with an output end of the first operational amplifier;

[0023] the first operational amplifier;

[0024] a comparator with a positive input end connected with an output end of the first operational amplifier and a negative input end connected with a reference voltage end;

[0025] The first end is connected with the positive pole of the first power supply, the second end is connected with the output end of the comparator, and the fourth resistor is connected as the output end of the voltage detection circuit.

[0026] Preferably, the current detection circuit comprises:

[0027] The input side first end is connected with the second end of the control coil, the input side second end is connected with the first end of the first switch tube, the output side second end is grounded, the first optocoupler is connected with the fifth resistor at the output side first end, and the connection end is connected as the output end of the current detection circuit.

[0028] The first end of the fifth resistor is connected with the positive pole of the second power supply.

[0029] The second end of the first switch tube is grounded, and the control end is connected with the second end of the sixth resistor and the first end of the seventh resistor.

[0030] The seventh resistor is grounded at the second end.

[0031] The first end of the sixth resistor is used for connecting the relay driving signal.

[0032] Preferably, the DC conversion circuit comprises:

[0033] The first diode is connected in parallel with the control coil and used for freewheeling of the control coil.

[0034] Preferably, the DC conversion circuit is a boost circuit.

[0035] Preferably, the hardware drive blocking circuit comprises:

[0036] The second switch tube is grounded at the second end, and the control end is connected as the input end of the hardware drive blocking circuit to receive the second fault signal.

[0037] The eighth resistor is connected with the control end of the second switch tube at the first end and grounded at the second end.

[0038] The diode unit comprises N diodes connected in parallel, the cathode of each diode in the diode unit is connected with the first end of the second switch tube, and the anode of each diode in the diode unit is connected with the control end of each controllable switch tube in the DC conversion driving circuit, so that when the hardware drive blocking circuit receives the second fault signal, the control end of each controllable switch tube in the DC conversion driving circuit is grounded through the second switch tube; N is a positive integer.

[0039] Preferably, the DC conversion driving circuit comprises:

[0040] The first capacitor is connected in parallel with the eighth resistor.

[0041] Preferably, further comprising:

[0042] The first end is an input end of the hardware drive blocking circuit, and the second end is connected with the control end of the second switch tube.

[0043] A UPS comprising the relay protection circuit as described above.

[0044] With the technical scheme provided by the embodiment of the application, the applicant considers that if a single-point fault of the relay occurs during normal load operation, the contact group of the relay will be disconnected, but not immediately, but with a certain delay, therefore, during the delay time, the loop in which the contact group is located is disconnected through the direct-current conversion circuit, so that the zero-current shutdown of the contact group can be realized, and the direct-current breaking of the relay will not occur. Specifically, in the scheme of the application, a coil detection circuit is arranged, which can output a first fault signal to the controller and a second fault signal to the hardware drive blocking circuit when detecting that the control coil is in an abnormal working state. Therefore, when the single-point fault of the relay occurs, the coil detection circuit can detect that the control coil is in an abnormal working state, at this time, the relay contact group has not been disconnected. The coil detection circuit sends the first and second fault signals, so that the direct-current conversion drive circuit is switched to a non-working state, thereby shutting down the loop in which the direct-current conversion circuit is located, that is, the loop in which the relay contact group is located is disconnected, therefore, when the relay contact group is disconnected, the zero-current shutdown is realized. Moreover, the second fault signal is sent to the hardware drive blocking circuit, and the hardware drive blocking circuit can adjust the circuit state thereof to switch the direct-current conversion drive circuit to a non-working state when receiving the second fault signal, that is, the drive blocking of the direct-current conversion drive circuit is directly realized through hardware, which is beneficial to guarantee the effectiveness and rapidity of the drive blocking. At the same time, the first fault signal is sent to the controller, and the controller controls the direct-current conversion drive circuit to be switched to a non-working state, that is, the control of the direct-current conversion drive circuit is realized through software, and the redundancy of the drive blocking can be realized. That is, through the redundancy of hardware + software, it can be guaranteed that the direct-current conversion drive circuit can be effectively switched to a non-working state, that is, the reliability of the scheme is improved. In summary, the application can effectively avoid the direct-current breaking of the relay, and guarantee the reliability of the circuit. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical schemes in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0046] Figure 1 Figure 1 is a structural schematic diagram of a relay protection circuit according to an embodiment of the present application.

[0047] Figure 2 Figure 2 is a structural schematic diagram of a coil detection circuit according to an embodiment of the present application.

[0048] Figure 3 Figure 3 is a structural schematic diagram of a hardware drive blocking circuit according to an embodiment of the present application. DETAILED DESCRIPTION

[0049] The core of the present application is to provide a relay protection circuit, which can effectively avoid the situation of direct current breaking of a relay, and guarantee the reliability of the circuit.

[0050] In order for those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0051] Reference should be made to Figure 1 , Figure 1 Figure 1 is a structural schematic diagram of a relay protection circuit according to an embodiment of the present application. The relay protection circuit can include:

[0052] A relay K1 including a control coil and a contact group, a first end of the contact group being connected with a first direct current power supply, and a second end of the contact group being connected with a direct current conversion circuit 10;

[0053] A relay drive circuit 20 connected with the control coil, for driving control of the control coil under the control of a controller 30;

[0054] A coil detection circuit 40, for outputting a first fault signal to the controller 30 and outputting a second fault signal to a hardware drive blocking circuit 50 when detecting that the control coil is in an abnormal working state;

[0055] The hardware drive blocking circuit 50 connected with the direct current conversion drive circuit 60, for adjusting the circuit state of itself to switch the direct current conversion drive circuit 60 to a non-working state when receiving the second fault signal;

[0056] The controller 30 connected with the direct current conversion drive circuit 60, for controlling the direct current conversion drive circuit 60 to switch to a non-working state when receiving the first fault signal;

[0057] The direct current conversion circuit 10;

[0058] The DC-DC converter drive circuit 60, which is connected to the DC-DC converter circuit 10, is used to drive and control the DC-DC converter circuit 10.

[0059] Specifically, relay K1 includes a control coil and a contact group. The on / off state of the contact group is controlled by the control coil. When the terminal voltage of the control coil is higher than the rated voltage, the control coil can attract the contact group, making the contact group conductive, thus connecting the first DC power supply to the DC-DC converter circuit 10. Conversely, when the terminal voltage of the control coil is lower than the rated voltage, the contact group is off, thus disconnecting the electrical connection between the first DC power supply and the DC-DC converter circuit 10.

[0060] The specific type of relay K1 in this application can be set and adjusted according to actual needs. It can be a single-contact relay K1 or a multi-contact relay K1. Of course, if it is a multi-contact relay K1, the circuit structure of this application only needs to use one of the contact groups and the control coil for controlling the on and off of the contact group.

[0061] The first end of the contact group is connected to a first DC power supply. The specific type of the first DC power supply can be set and adjusted as needed, and is typically a USP DC power supply. The second end of the contact group is connected to a DC-DC converter circuit 10. The DC-DC converter circuit 10 can be a boost circuit, a buck circuit, or a boost-buck circuit, etc., without affecting the implementation of the present invention. Of course, in practical applications, the DC-DC converter circuit 10 is typically a boost circuit. The output of the boost circuit can be connected to the bus capacitor, and then directly or indirectly electrically connected to the load, thereby enabling the first DC power supply to power the load.

[0062] The relay drive circuit 20 is connected to the control coil of relay K1 and can drive the control coil under the control of controller 30. The relay drive circuit 20 has a very simple structure and high reliability; for example, it can be implemented using several controllable switches.

[0063] The coil detection circuit 40 is connected to the control coil and can detect whether the control coil is currently in an abnormal working state. For example, it can determine whether the control coil is currently in an abnormal working state by detecting the voltage of the control coil, or by detecting the current of the control coil.

[0064] In one specific embodiment of the present invention, see [reference needed]. Figure 2 The coil detection circuit 40 may include: a current detection circuit for detecting whether the coil current of the control coil is abnormal, and a voltage detection circuit for detecting whether the coil voltage of the control coil is abnormal.

[0065] The coil detection circuit 40 is specifically used for:

[0066] When the current detection circuit detects that the coil current is abnormal, or when the voltage detection circuit detects that the coil voltage is abnormal, it is determined that the control coil is in an abnormal working state, a first fault signal is output to the controller 30, and a second fault signal is output to the hardware drive blocking circuit 50.

[0067] In this embodiment, if the current working state of the control coil is determined only by detecting the voltage of the control coil, if the control coil is open, the control coil cannot attract the contact group any more, but the voltage detection circuit usually detects the terminal voltage of the control coil, and even if the control coil is open, the terminal voltage of the control coil is still high, even equal to the power supply terminal voltage for supplying power to the control coil. That is, in this case, the fault condition cannot be determined by detecting the voltage of the control coil that the control coil is currently in an abnormal working state.

[0068] And in this embodiment, if the current working state of the control coil is determined only by detecting the current of the control coil, in some cases, the current of the control coil may be gradually decreasing, and by the time the control coil is determined to be in an abnormal working state by detecting the current of the control coil, the contact group may have already been DC broken.

[0069] To this end, in this embodiment, the current detection circuit and the voltage detection circuit are provided at the same time, whether the coil current is abnormal detected by the current detection circuit or the coil voltage is abnormal detected by the voltage detection circuit, it is determined that the control coil is in an abnormal working state, that is, the redundant detection of the abnormal working state of the control coil is realized.

[0070] Of course, the specific structure of the current detection circuit and the voltage detection circuit can be set and adjusted according to actual needs, for example, in a specific embodiment of the present application, the voltage detection circuit comprises:

[0071] The first end is connected with the first end of the control coil as the first detection end of the voltage detection circuit, and the second end is connected with the positive input end of the first operational amplifier OP1 through the first resistor R1;

[0072] The first end is connected with the second end of the control coil as the second detection end of the voltage detection circuit, and the second end is connected with the negative input end of the first operational amplifier OP1 and the first end of the third resistor R3 through the second resistor R2;

[0073] The second end of the third resistor R3 is connected with the output end of the first operational amplifier OP1;

[0074] The first operational amplifier OP1;

[0075] The negative input end is connected with the output end of the first operational amplifier OP1, and the positive input end is connected with the reference voltage end of the comparator A1.

[0076] The first end is connected with the positive pole of the first power supply, the second end is connected with the output end of the comparator A1, and the connecting end is the fourth resistor R4 as the output end of the voltage detection circuit.

[0077] The voltage detection circuit in the embodiment has simple structure and high reliability. In other embodiments, other types of voltage detection circuits can be selected according to needs, as long as the functions of the voltage detection circuit can be realized.

[0078] Figure 2 In the embodiment, the first resistor R1, the second resistor R2, the third resistor R3 and the first operational amplifier OP1 constitute a differential operational amplifier type voltage detection circuit, that is, the output of the first operational amplifier OP1 can effectively reflect the terminal voltage of the control coil. The comparator A1 compares the output voltage of the first operational amplifier OP1 with the voltage of the reference voltage end, Figure 2 In the embodiment, the reference voltage end is marked as V_SET.

[0079] It can be understood that when the UPS normally runs with load, the contact group is turned on, and the terminal voltage of the control coil is higher than the rated voltage. At this time, the output voltage of the first operational amplifier OP1 should be higher than V_SET, the comparator A1 outputs a low-level signal, that is, Figure 2 The V_Fault signal is low at this time. Correspondingly, when an abnormal situation occurs, resulting in a low coil voltage of the control coil, the output voltage of the first operational amplifier OP1 is not higher than V_SET, at this time, the comparator A1 outputs a high-level signal, that is, Figure 2 The V_Fault signal is high at this time, indicating that the voltage detection circuit detects that the coil voltage of the control coil is abnormal.

[0080] In a specific embodiment of the application, the current detection circuit can comprise:

[0081] The input side first end is connected with the second end of the control coil, the input side second end is connected with the first end of the first switch tube Q1, the output side second end is grounded, the first optocoupler OC1 has the output side first end connected with the second end of the fifth resistor R5 and the connecting end as the output end of the current detection circuit;

[0082] The first end of the fifth resistor R5 is connected with the positive pole of the second power supply;

[0083] The second end is grounded, and the control end is connected with the second end of the sixth resistor R6 and the first end of the seventh resistor R7.

[0084] The second end of the seventh resistor R7 is grounded.

[0085] The first end of the sixth resistor R6 is used for connecting a relay drive signal.

[0086] In this embodiment, the current detection is realized based on the optical coupling, and the sensitivity is high. In other embodiments, the current detection mode based on the series resistor + isolation sampling, the current detection mode based on the current transformer, and the like can be selected, and the implementation of the application is not affected.

[0087] It should be further pointed out that, Figure 2 In the embodiment, the first end of the sixth resistor R6 is used for connecting a relay drive signal, that is, to make the control coil of the relay K1 powered, the first switch tube Q1 needs to be turned on by the relay drive signal first, and then the control coil of the relay K1 can form a loop with the corresponding power supply. In actual application, the relay drive signal can be sent by the controller 30. Of course, only after the first switch tube Q1 is turned on, the current detection circuit can effectively detect the current of the control coil.

[0088] In addition, it should be pointed out that the control coil of the relay K1 needs to be powered, Figure 2 In the embodiment, the first end of the control coil of the relay K1 is connected to the power supply VCC for powering the control coil of the relay K1. In addition, Figure 2 In the embodiment, the first power supply and the second power supply are both VCC, which is more convenient. Of course, in other embodiments, other power supplies can be used as needed, and the implementation of the application is not affected.

[0089] When normally running with load, the contact group is turned on, the current flowing through the control coil is high, the primary diode of the first optical coupling OC1 is turned on, that is, the first end and the second end of the input side of the first optical coupling OC1 are turned on, at this time, the secondary side is also turned on, that is, the first end and the second end of the output side of the first optical coupling OC1 are turned on, Figure 2 The I_Fault signal in the embodiment is low. Correspondingly, when the current flowing through the control coil is low, the primary diode of the first optical coupling OC1 is not turned on, and the secondary side is turned off, at this time Figure 2 The I_Fault signal in the embodiment is high.

[0090] In addition, it should be pointed out that, in Figure 2 In the embodiment, when the voltage detection circuit detects that the coil voltage of the control coil is abnormal, the V_Fault signal is high, and when the current detection circuit detects that the coil current of the control coil is abnormal, the I_Fault signal is also high, so V_Fault and I_Fault can be directly connected as the output of the coil detection circuit 40, that is, if the hardware drive blocking circuit 50 adopts the embodiment of Figure 3 In the embodiment, V_Fault and I_Fault can be directly connected asFigure 3 But in other embodiments, if the V_Fault signal level when the voltage is abnormal and the I_Fault signal level when the current is abnormal are inconsistent, a level conversion, logic conversion or other circuit can be set to obtain the input signal of the hardware drive blocking circuit 50, i.e., the fault signal output by the coil detection circuit 40.

[0091] In Figure 2 In the embodiments of the present application, a first diode D1 is also arranged in parallel with the control coil to provide freewheeling for the control coil. The freewheeling through the first diode D1 can provide a discharge circuit for the control coil, thereby achieving fast discharge of the control coil. This makes the voltage and current of the control coil decrease rapidly when the control coil loses power, so that the control coil can be detected by the voltage detection circuit and the current detection circuit more timely.

[0092] The coil detection circuit 40 needs to output a fault signal to the hardware drive blocking circuit 50 and the controller 30. In the scheme of the present application, the fault signal output to the controller 30 is referred to as a first fault signal, and the fault signal output to the hardware drive blocking circuit 50 is referred to as a second fault signal. Through the two fault signals, the DC conversion drive circuit 60 is blocked in hardware and software, i.e., the redundancy of the blocking mode is achieved, so that when the coil detection circuit 40 detects that the control coil is in an abnormal working state, the DC conversion drive circuit 60 can be effectively switched to a non-working state. The DC conversion drive circuit 60 can drive the DC conversion circuit 10, so when the DC conversion drive circuit 60 is switched to a non-working state, the DC conversion circuit 10 cannot work and will be in an open circuit state.

[0093] Specifically, when the controller 30 receives the first fault signal, it controls the DC conversion drive circuit 60 to switch to a non-working state. Since the controller 30 in actual application usually controls the DC conversion drive circuit 60 through a PWM signal, when the controller 30 receives the first fault signal, it can set the duty cycle of the PWM signal to 0, i.e., no longer output the PWM signal, so that the DC conversion drive circuit 60 is switched to a non-working state.

[0094] The blocking in hardware needs to be realized through the hardware drive blocking circuit 50. The specific structure of the hardware drive blocking circuit 50 can be set and adjusted as needed, as long as the hardware drive blocking circuit 50 can effectively switch the DC conversion drive circuit 60 to a non-working state through a hardware circuit after adjusting the circuit state of the hardware drive blocking circuit 50.

[0095] For example, in a specific embodiment of the present application, reference can be made to Figure 3The hardware-driven blocking circuit 50 may include:

[0096] The control terminal serves as the input terminal of the hardware-driven blocking circuit 50 to receive the second fault signal, and the second terminal is grounded, which is the second switch Q2.

[0097] The eighth resistor R8 has its first terminal connected to the control terminal of the second switch Q2 and its second terminal grounded.

[0098] The diode unit includes N diodes connected in parallel. The cathode of each diode in the diode unit is connected to the first terminal of the second switch Q2. The anode of each diode in the diode unit is connected to the control terminal of each controllable switch in the DC-DC converter drive circuit 60, so that when the hardware drive blocking circuit 50 receives the second fault signal, the control terminal of each controllable switch in the DC-DC converter drive circuit 60 is grounded through the second switch Q2.

[0099] The hardware-driven blocking circuit 50 in this embodiment has a simple structure and high reliability.

[0100] When the coil detection circuit 40 does not output a second fault signal Figure 3 When the input of the hardware-driven blocking circuit 50, namely Fault_Signal, is low, the second switch Q2 is off. However, when the coil detection circuit 40 outputs the second fault signal, Fault_Signal is high, and the second switch Q2 is on.

[0101] After the second switch Q2 is turned on, the control terminals of each controllable switch in the DC-DC converter drive circuit 60 are connected via... Figure 3 Each diode in the circuit is grounded, meaning the control terminals of each controllable switch are pulled low to 0, thus achieving hardware isolation of the DC-DC converter drive circuit 60. N is a positive integer, depending on the number of controllable switches in the DC-DC converter drive circuit 60; it can be one or more. Figure 3 In the N=2, the diode unit includes diodes D21 and D22 connected in parallel, which are respectively connected to the control terminals of the two controllable switching transistors in the DC-DC converter drive circuit 60, and are labeled as Boost_DRV1 and Boost_DRV2 respectively.

[0102] Furthermore, in Figure 3 In some implementations, a first capacitor C1 connected in parallel with the eighth resistor R8 may also be included to ensure the stability of the control terminal voltage of the second switch Q2 and to avoid abnormal situations caused by sudden level changes.

[0103] Furthermore, in Figure 3In the embodiment, the first end is an input end of the hardware drive blocking circuit 50, and the second end is connected with the control end of the second switch tube Q2 through the ninth resistor R9. The current is limited through the ninth resistor R9, so that the second switch tube Q2 is prevented from being damaged by excessive current.

[0104] According to the technical scheme provided by the embodiment of the application, the applicant considers that if a single-point fault of the relay occurs during normal load operation, the contact group of the relay K1 will be disconnected, but not immediately, but with a certain delay. Therefore, during the delay time, the loop in which the contact group is located is disconnected through the direct-current conversion circuit 10, so that the zero-current shutdown of the contact group is realized, and the direct-current breaking of the relay K1 is avoided. Specifically, in the scheme of the application, the coil detection circuit 40 is arranged. When the coil detection circuit 40 detects that the control coil is in an abnormal working state, the coil detection circuit 40 outputs a first fault signal to the controller 30 and outputs a second fault signal to the hardware drive blocking circuit 50. Therefore, when the single-point fault of the relay K1 occurs, the coil detection circuit 40 can detect that the control coil is in an abnormal working state, and at this time, the contact group of the relay K1 has not been disconnected. The coil detection circuit 40 sends the first and second fault signals, so that the direct-current conversion drive circuit 60 is switched to a non-working state, so that the loop in which the direct-current conversion circuit 10 is located is shut down, that is, the loop in which the contact group of the relay K1 is located is disconnected. Therefore, when the contact group of the relay K1 is disconnected, the zero-current shutdown is realized. Moreover, the second fault signal is sent to the hardware drive blocking circuit 50. When the second fault signal is received, the hardware drive blocking circuit 50 can adjust the circuit state of the hardware drive blocking circuit 50, so as to switch the direct-current conversion drive circuit 60 to a non-working state, that is, the drive blocking of the direct-current conversion drive circuit 60 is realized directly through hardware, which is beneficial to guarantee the effectiveness and rapidity of the drive blocking. At the same time, the first fault signal is sent to the controller 30, and the controller 30 controls the direct-current conversion drive circuit 60 to be switched to a non-working state. The control of the direct-current conversion drive circuit 60 is realized through software, so that the redundancy of the drive blocking is realized. That is, through the redundancy of hardware + software, the direct-current conversion drive circuit 60 can be effectively switched to a non-working state, that is, the reliability of the scheme is improved. In summary, the application can effectively avoid the direct-current breaking of the relay K1, and guarantee the reliability of the circuit.

[0105] Corresponding to the above embodiment of the relay protection circuit, the embodiment of the application further provides a UPS, which can include the relay protection circuit in any of the above embodiments.

[0106] It is also important to note that the use of relational terms such as first and second, and the like, are used solely to distinguish one from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a... " does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0107] Those skilled in the art will further appreciate that the units and algorithms described in connection with the examples disclosed herein can be embodied directly in hardware, in software, or in a combination of the two. For the sake of brevity, descriptions of these conventional implementations are not included herein. Those skilled in the art will understand that the functions of the examples described herein can be implemented in software, hardware, or a combination thereof. As such, the disclosure is not limited to any particular type of hardware or software. The implementation of a feature or function described herein as being carried out by a unit, module, or the like can be carried out by that unit or module or by a single unit or module.

[0108] The principles and implementations of the present application have been described above with the specific examples. The above description of the examples is only for the purpose of understanding the technical solutions and the core ideas of the present application. It should be pointed out that, for those skilled in the art, without departing from the principles of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the present application.

Claims

1. A relay protection circuit, characterized in that, include: A relay including a control coil and a contact group, wherein a first end of the contact group is connected to a first DC power supply and a second end of the contact group is connected to a DC-DC converter circuit; A relay drive circuit connected to the control coil is used to drive the control coil under the control of the controller; The coil detection circuit is used to output a first fault signal to the controller and a second fault signal to the hardware driver blocking circuit when the control coil is detected to be in an abnormal working state. The hardware drive blocking circuit connected to the DC-DC converter drive circuit is used to adjust its own circuit state when receiving the second fault signal, so as to switch the DC-DC converter drive circuit to a non-working state, so that the DC-DC converter circuit is in an open circuit state. The controller connected to the DC-DC converter drive circuit is used to set the duty cycle of the PWM signal to 0 when the first fault signal is received, and control the DC-DC converter drive circuit to switch to a non-working state. The DC-DC converter circuit; The DC-DC converter drive circuit connected to the DC-DC converter circuit is used to drive and control the DC-DC converter circuit.

2. The relay protection circuit according to claim 1, characterized in that, The coil detection circuit includes: a current detection circuit for detecting whether the coil current of the control coil is abnormal, and a voltage detection circuit for detecting whether the coil voltage of the control coil is abnormal. The coil detection circuit is specifically used for: When the current detection circuit detects an abnormal coil current, or when the voltage detection circuit detects an abnormal coil voltage, it determines that the control coil is in an abnormal operating state, outputs a first fault signal to the controller, and outputs a second fault signal to the hardware drive blocking circuit.

3. The relay protection circuit according to claim 2, characterized in that, The voltage detection circuit includes: The first terminal serves as the first detection terminal of the voltage detection circuit and is connected to the first terminal of the control coil; the second terminal is connected to the first resistor at the positive input terminal of the first operational amplifier. The first terminal serves as the second detection terminal of the voltage detection circuit and is connected to the second terminal of the control coil. The second terminal is connected to the negative input terminal of the first operational amplifier and the second resistor of the third resistor. The third resistor whose second terminal is connected to the output terminal of the first operational amplifier; The first op-amp; A comparator whose negative input terminal is connected to the output terminal of the first operational amplifier and whose positive input terminal is connected to the reference voltage terminal; The first terminal is connected to the positive terminal of the first power supply, and the second terminal is connected to the output terminal of the comparator, with the connection terminal serving as the fourth resistor of the output terminal of the voltage detection circuit.

4. The relay protection circuit according to claim 2, characterized in that, The current detection circuit includes: The first input end is connected to the second end of the control coil, the second input end is connected to the first end of the first switching transistor, the second output end is grounded to the first optocoupler, and the first output end of the first optocoupler is connected to the second end of the fifth resistor, with the connection end serving as the output end of the current detection circuit. The fifth resistor, whose first end is connected to the positive terminal of the second power supply; The first switch transistor with its second terminal grounded and its control terminal connected to the second terminal of the sixth resistor and the first terminal of the seventh resistor respectively; The seventh resistor with its second terminal grounded; The first terminal is used to connect the sixth resistor to the relay drive signal.

5. The relay protection circuit according to claim 1, characterized in that, Also includes: A first diode connected in parallel with the control coil to provide freewheeling current to the control coil.

6. The relay protection circuit according to claim 1, characterized in that, The DC-DC converter circuit is a boost circuit.

7. The relay protection circuit according to any one of claims 1 to 6, characterized in that, The hardware-driven blocking circuit includes: The control terminal serves as the input terminal of the hardware-driven blocking circuit to receive the second fault signal, and the second terminal is grounded as the second switching transistor; The eighth resistor has its first end connected to the control terminal of the second switching transistor and its second end grounded. The diode unit comprises N diodes connected in parallel. The cathodes of each diode in the diode unit are connected to the first terminal of the second switching transistor. The anodes of each diode in the diode unit are connected to the control terminals of each controllable switching transistor in the DC-DC converter drive circuit, so that when the hardware drive blocking circuit receives the second fault signal, the control terminals of each controllable switching transistor in the DC-DC converter drive circuit are grounded through the second switching transistor; N is a positive integer.

8. The relay protection circuit according to claim 7, characterized in that, Also includes: The first capacitor connected in parallel with the eighth resistor.

9. The relay protection circuit according to claim 7, characterized in that, Also includes: The first terminal serves as the input terminal of the hardware-driven blocking circuit, and the second terminal is connected to the ninth resistor, which is connected to the control terminal of the second switching transistor.

10. A UPS, characterized in that, Includes the relay protection circuit as described in any one of claims 1 to 9.

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