Front-end anti-adhesion protection circuit and electric equipment

Abstract

The utility model discloses a front-end anti-adhesion protection circuit and electric equipment, and the front-end anti-adhesion protection circuit comprises a relay which is connected between a power supply front end and a power supply rear end of a power supply, and also comprises a current limiting circuit which is connected between the power supply front end and the power supply rear end. The current limiting circuit is provided with at least one current limiting unit with an adjustable resistance value, and the resistance value of the current limiting unit is the maximum value when the power supply is powered on and is the minimum value when the power supply works stably. Compared with the prior art, the resistance value of the current limiting unit is the maximum value when the power supply is powered on, peak current can be restrained, the adhesion phenomenon of the relay is avoided, meanwhile, when the voltage difference between the power supply front end and the power supply rear end is too large, the peak current can be absorbed through the absorption circuit, the circuit is further protected, and the service life of the circuit is prolonged. And the service life and the use safety of the relay are greatly improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to relay sticking protection, especially a front end anti -sticking protection circuit and electrical equipment. BACKGROUND

[0002] In the debugging environment of energy storage converter, there are multiple power-off and power-on situations, and before power-off, the bus capacitor may retain 100V-400V bus voltage, and after the DC load is disconnected, the voltage will drop to zero, and after reconnection at the front end, due to the internal capacitor of the DC load, if the DC side of the converter still has a large voltage at this time, the internal capacitor of the DC load will be charged when the DC load is connected, and due to the large voltage difference, a large inrush peak current will be generated. Due to the closure of the front-end relay for a moment, it will cause the contact to produce a transient arc, which will melt the relay contact and cause sticking.

[0003] To avoid the above-mentioned sticking problem, the patent with patent number CN103715013B uses a bipolar relay, and the first contact of the two relays is connected in the application circuit, and the second contact is controlled to act simultaneously with the first contact. When one road triggers sticking, the other relay can still work, although the problem is solved, but the problem of large inrush peak current still exists.

[0004] The patent with patent number CN110148544B judges whether the relay is in an abnormal closed state; if so, a control instruction is sent to the relay; it is judged whether the control instruction and the relay received instruction are abnormal; if abnormal, a low-level control instruction is continuously sent to the relay to make the relay continuously open. This patent only solves the problem of re-opening after sticking by judging, and does not design the suppression protection for inrush peak current.

[0005] The patent with patent number CN113295995B detects the sticking of each relay, detects the detection point voltage signal and the voltage across the battery at each relay, and judges the sticking state of the relay according to the voltage difference between the detection point voltage and the voltage across the battery. This patent only judges the sticking state, and does not design the suppression protection for inrush peak current.

[0006] It can be seen that although the existing patents point out the existence of sticking problem, they do not essentially suppress the peak current, and the sticking fault of the relay cannot be well solved, therefore, how to design a front-end anti-sticking protection circuit and electrical equipment to avoid the occurrence of relay sticking problem is a technical problem to be solved in the industry. Utility model content

[0007] The utility model provides a front end anti -sticking protection circuit and electric equipment for the relay sticking problem caused by the existence of the peak current in prior art.

[0008] The technical scheme of the utility model provides a front end anti -sticking protection circuit, including the relay of connecting between the power supply front end and the power supply rear end of power supply, still including the current -limiting circuit of connecting between the power supply front end and the power supply rear end, the current -limiting circuit has at least one resistance value adjustable current -limiting unit, the resistance value of current -limiting unit is at maximum when power supply is powered on, and at minimum when the power supply works stably.

[0009] Further, it further includes a detection unit connected to the power supply front end and the power supply rear end respectively, and an absorption circuit connected between the power supply front end and the power supply rear end.

[0010] The detection unit is used for detecting the voltage parameters of the power supply front end and the power supply rear end, and the absorption circuit is turned on to absorb the peak current between the power supply front end and the power supply rear end when the voltage parameters exceed the preset threshold.

[0011] Further, the power supply has a first power supply front end, a second power supply front end, a first power supply rear end and a second power supply rear end.

[0012] The first power supply front end is connected to the first power supply rear end, the second power supply front end is connected to the second power supply rear end, and the connection line of the first power supply front end and the first power supply rear end is connected to the connection line of the second power supply front end and the second power supply rear end.

[0013] Further, the relay is connected in series between the first power supply front end and the first power supply rear end, and the current -limiting unit is connected in series between the second power supply front end and the second power supply rear end.

[0014] Further, the absorption circuit includes a first resistor, a first capacitor and a switching switch.

[0015] One end of the first resistor is connected between the first power supply front end and the first power supply rear end, the other end of the first resistor is connected to one end of the first capacitor, the other end of the first capacitor is connected to one end of the switching switch, and the other end of the switching switch is connected between the second power supply front end and the second power supply rear end.

[0016] Further, the absorption circuit further includes a bleeder resistor, and the bleeder resistor is connected in parallel across the first capacitor.

[0017] Further, the absorption circuit further comprises an anti-reverse connection diode, a negative electrode of the anti-reverse connection diode is connected between the first power supply front end and the first power supply rear end, and a positive electrode of the anti-reverse connection diode is connected between the first resistor and the first capacitor.

[0018] Further, the current limiting unit is an adjustable resistor.

[0019] Further, the switching switch is a relay.

[0020] The utility model also provides a kind of electric equipment, and the electric equipment has the front end anti-adhesion protection circuit described above.

[0021] Compared with prior art, the utility model at least has following beneficial effects:

[0022] 1, the utility model sets up current limiting circuit, this current limiting circuit is connected between power supply front end and power supply rear end, and the current limiting circuit is powered on power supply, resistance value is at maximum value, can produce good inhibitory effect to the sharp peak current at this time, avoid the problem that sharp peak current causes influence to relay, appears adhesion fault;

[0023] 2, in the utility model, when power supply works stably, the resistance value of current limiting unit is at minimum value, can reduce the loss of current limiting unit to whole loop;

[0024] 3, the utility model further sets up absorption circuit, can further absorb the sharp peak current generated when the voltage difference between power supply front end and power supply rear end exceeds preset threshold value, avoid the adhesion fault of relay, greatly improve the service life and use safety of relay. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical scheme in the embodiment of the utility model, the following will be briefly introduced to the drawings needed to be used in embodiment or prior art description, obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to these drawings without creative labor.

[0026] Figure 1 It is the circuit topology of the front end anti-adhesion protection circuit in the utility model;

[0027] Figure 2 It is the work flow chart of the front end anti-adhesion protection circuit in the utility model. DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical schemes and beneficial effects of the utility model clearer and more apparent, the utility model will be further described in detail below in combination with the drawings and embodiments.

[0029] Therefore, one feature indicated in the specification will be used to explain one feature of one embodiment of the utility model, instead of implying that each embodiment of the utility model must have the explained feature. In addition, it should be noted that the specification describes many features. Although certain features can be combined together to show possible system design, these features can also be used in other combinations which are not explicitly explained. Therefore, the explained combinations are not intended to be limiting unless otherwise stated.

[0030] The principle and structure of the utility model will be described in detail below in combination with the drawings and embodiments.

[0031] Please refer to Figure 1 , K1 is a main loop relay, when the relay K1 is closed, the DC positive pole of the external butt joint battery, power supply and other DC devices is connected to the loop, but because the voltage of the power supply back end (in the Figure 1 , it is zero, if the voltage difference between the power supply front end and the power supply back end is large, a large peak current will be drawn, which will cause the relay K1 to have a sticking fault, thereby affecting the use of the DC device.

[0032] In view of the above problems, the utility model provides a front end anti-sticking protection circuit, which comprises a relay connected between the power supply front end and the power supply back end of a power supply, and a current limiting circuit connected between the power supply front end and the power supply back end.

[0033] The current limiting circuit has at least one current limiting unit with adjustable resistance, and the resistance of the current limiting unit is at a maximum value when the power supply is powered on, and is at a minimum value when the power supply is working stably.

[0034] The relay referred to here is the relay K1 in Figure 1 , the relay K1 has a risk of sticking fault when there is a voltage difference between the power supply front end and the power supply back end, and the current limiting circuit is mainly used to limit the generated peak current, thereby avoiding the occurrence of sticking fault.

[0035] The current limiting circuit suppresses the peak current according to Ohm's law, in the case of a certain voltage, the greater the resistance, the smaller the current, therefore the utility model pulls the resistance of the current limiting unit in the current limiting circuit to the maximum value when the power supply is powered on, at this time the peak current in the loop will be suppressed to the maximum extent, thereby avoiding the occurrence of sticking fault of the relay K1 caused by too large peak current.

[0036] The current limiting unit in the utility model adopts adjustable resistance instead of fixed resistance, because if a fixed large resistance is used to limit the peak current, the large resistance connected to the circuit will cause high power loss after the circuit returns to normal, resulting in energy waste, the adjustable resistance is used in the utility model, after the peak current is limited by using the maximum resistance value, the circuit returns to normal operation, the resistance value can be adjusted to the minimum value, the power loss generated on the adjustable resistance is extremely low at this time, which can be ignored, so energy waste will not be caused.

[0037] It should be noted that the number of current limiting units provided in the current limiting circuit in the utility model can be more than one, in other embodiments of the utility model, multiple current limiting units can also be provided, the resistance values of the multiple current limiting units can be adjusted by series connection, parallel connection and other methods, and the above-mentioned effect can also be achieved.

[0038] In addition, in other embodiments of the utility model, the current limiting unit is not limited to the form of adjustable resistance, and the resistance value can also be adjusted by using multiple fixed resistors in cooperation with corresponding adjustment switches, and the above-mentioned effect can also be achieved.

[0039] The most important difference between the utility model and the traditional scheme is that the utility model suppresses the peak current by using the current limiting unit before the peak current is generated, because of the high resistance value of the current limiting unit, even if the voltage difference between the power supply front end and the power supply rear end meets the condition of generating the peak current, the peak current will be suppressed by the current limiting unit and cannot be generated, therefore, in the utility model, the peak current will not appear in essence. However, the schemes in the prior art are all after the peak current appears in the loop, and then how to suppress the peak current is considered. Although the above-mentioned scheme and the utility model can suppress the peak current, they are not the same in essence, although the peak current is suppressed in the existing scheme, the moment when the peak current is generated will still cause damage to the components in the circuit, and even the relay K1 may still have a sticking fault.

[0040] Further, the utility model still includes detection units connected with the power supply front end and the power supply rear end respectively, and an absorption circuit connected between the power supply front end and the power supply rear end.

[0041] The detection unit is used for detecting the voltage parameters of the power supply front end and the power supply rear end, and the absorption circuit is turned on to absorb the peak current between the power supply front end and the power supply rear end when the voltage parameters exceed the preset threshold.

[0042] As described above, the condition of the spike current generation is that there is a large voltage difference between the power supply front end and the power supply rear end, although the utility model can inhibit the generation of the spike current through the current limiting unit, but for some specific conditions, the voltage difference between the power supply front end and the power supply rear end is too large, at this time, only through the current limiting unit cannot completely inhibit the appearance of the spike current, for this, the utility model is designed with the absorption circuit, the absorption circuit is connected between the power supply front end and the power supply rear end, for conducting when the current limiting unit is insufficient to limit the spike current generation, to absorb the spike current generated at this time, avoid the sticking problem of the relay.

[0043] In the utility model, the power supply has a first power supply front end, a second power supply front end, a first power supply rear end and a second power supply rear end.

[0044] The first power supply front end is connected with the first power supply rear end, the second power supply front end is connected with the second power supply rear end, and the connecting line of the first power supply front end and the first power supply rear end is connected with the connecting line of the second power supply front end and the second power supply rear end.

[0045] Please refer to Figure 1 In the utility model, the power supply is a direct current power supply, the first power supply front end is the input positive pole of the direct current power supply, that is, DC+ in the attached Figure 1 , the second power supply front end is the input negative pole of the direct current power supply, that is, DC- in the attached Figure 1 , the first power supply rear end is the output positive pole of the direct current power supply, that is, U-DC+ in the attached Figure 1 , and the second power supply rear end is the output negative pole of the direct current power supply, that is, U-DC- in the attached Figure 1 .

[0046] When the circuit works normally, the current of the power supply is output from the first power supply front end and the second power supply front end respectively, and then is output through the first power supply rear end and the second power supply rear end, here, since the connecting line of the first power supply front end and the first power supply rear end is connected with the connecting line of the second power supply front end and the second power supply rear end, the current flowing out of the first power supply front end also flows out through the first power supply rear end in actual application, for this, the utility model can better distribute the connection mode of the above-mentioned current limiting circuit and the absorption circuit.

[0047] In the utility model, the relay is connected between the first power supply front end and the first power supply rear end, and the current limiting unit is connected between the second power supply front end and the second power supply rear end.

[0048] Please refer to Figure 1 , the above-mentioned relay is relay K1, which is the main relay in the utility model, the current limiting unit adopts adjustable resistance, which is resistance R3 in the utility model, and the relay K1 is mainly used for controlling whether the power supply front end and the power supply rear end are connected, and the resistance R3 is used for limiting the spike current between the power supply front end and the power supply rear end.

[0049] In other embodiments of the utility model, the above-mentioned resistance R3 can also be arranged in series with the relay K1 and connected between the first power supply front end and the first power supply rear end;

[0050] Or the above-mentioned resistance R3 is arranged between the first power supply front end and the first power supply rear end and between the second power supply front end and the second power supply rear end, which can also achieve the same technical effect.

[0051] Further, the utility model discloses an absorption circuit, comprising: first resistance, first capacitance, switching switch,

[0052] One end of first resistance is connected to between first power supply front end and first power supply rear end, the other end of first resistance is connected to one end of first capacitance, the other end of first capacitance is connected to one end of switching switch, the other end of switching switch is connected to between second power supply front end and second power supply rear end.

[0053] Please refer to Figure 1 , first resistance is resistance R1, first capacitance is capacitor C1, and switching switch also adopts relay, which is relay K2 in the attached Figure 1 ;

[0054] Here, the absorption circuit mainly absorbs the peak current through capacitor C1, and the capacitor C1 is in series with the relay K2, therefore, the relay K2 can control the on-off state of the entire absorption circuit;

[0055] The utility model discloses a detection unit, which is front end sampling and rear end sampling in the attached Figure 1 , and the voltage parameter detected by the detection unit is the voltage difference between the first power supply front end and the first power supply rear end, or the voltage difference between the second power supply front end and the second power supply rear end.

[0056] As described above, if the voltage difference is too large, the current limiting unit cannot limit the generation of the peak current, at this time, the absorption circuit needs to be turned on, at this time, the relay K1 can be used to connect the absorption circuit to the entire loop, and the capacitor C2 can be used to absorb the generated peak current.

[0057] Here, the judgment condition of the too large voltage difference is a preset threshold, if the voltage difference is greater than the preset threshold, it indicates that the current limiting unit cannot limit the occurrence of the peak current at this time, and the absorption circuit needs to be turned on.

[0058] Further, the utility model discloses that the absorption circuit further comprises a bleeder resistor, and the bleeder resistor is connected in parallel across the first capacitor.

[0059] Please refer to Figure 1Resistor R2 is a bleeder resistor, and the first capacitor is capacitor C1. Since a resistor is an energy-consuming component, when it is connected in parallel with capacitor C1, some energy in capacitor C1 will flow from the positive terminal of capacitor C1, through resistor R2, and back to the negative terminal of capacitor C1. (Here, the positive and negative terminals of capacitor C1 are determined by the electrical energy it absorbs. If the first terminal of capacitor C1 receives electrical energy, then the first terminal of capacitor C1 is the positive terminal when capacitor C1 is discharging.)

[0060] Because capacitor C1 cannot absorb peak current indefinitely, the aforementioned bleeder resistor is required to discharge excess energy and prevent capacitor C1 from being damaged.

[0061] Furthermore, the absorption circuit in this invention also includes a reverse connection protection diode, the negative terminal of which is connected between the first power supply front end and the first power supply back end, and the positive terminal of which is connected between the first resistor and the first capacitor.

[0062] Please see Figure 1 The reverse polarity protection diode is also the one attached. Figure 1 The diode D1 in the circuit can achieve the above-mentioned reverse connection protection effect due to its unidirectional conduction characteristic.

[0063] Please see Figure 2 This is a flowchart of the overall process of this utility model, which includes the following processes:

[0064] 1. DC front-end connection, with a voltage difference between the front and back ends;

[0065] In this utility model, the power supply is a DC power supply, and the power supply front end is also attached. Figure 1 The DC front end, and the power supply back end, are also attached. Figure 1 The DC back end in the middle, the DC front end here is the power supply power supply mentioned above, there is a voltage difference between the front end and the DC back end.

[0066] 2. Calculate and compare the voltage difference between the front and rear ends by sampling the resistor;

[0067] This invention includes a sampling unit, which is specifically implemented using a sampling resistor. Figure 1 The data is displayed as front-end sampling and back-end sampling;

[0068] After the sampling unit samples the voltages of the DC front end and the DC back end respectively, it is also necessary to calculate the voltage difference between the DC front end and the DC back end, which is "calculating and comparing the voltage difference between the front and back ends" here.

[0069] 3.1 If the pressure difference is not significant, the main circuit relay K1 can be closed directly;

[0070] The pressure difference here is the voltage difference between the power supply front end and the power supply rear end, and the pressure difference is not large, that is, the voltage difference is less than a preset threshold, at this time, only through the current limiting unit can the generation of the sharp peak current be inhibited, and then the main loop relay K1 can be directly closed.

[0071] 3.2, according to the front and rear pressure difference, the resistance value of the adjustable resistor is adjusted;

[0072] Here, the corresponding case is that the pressure difference is large, but the sharp peak current can still be inhibited by the current limiting unit, the front and rear pressure difference here is the voltage difference between the power supply front end and the power supply rear end, and the adjustable resistor is the current limiting unit, because the size of the sharp peak current is determined according to the voltage difference between the power supply front end and the power supply rear end, therefore, after calculating the voltage difference between the power supply front end and the power supply rear end, the resistance value of the current limiting unit can be adjusted to adaptively limit the generation of the sharp peak current;

[0073] 4, in the case of large difference, first close the relay K2 of the absorption loop, and connect the absorption capacitor to the loop;

[0074] Here, the large difference is that the voltage difference between the power supply front end and the power supply rear end is greater than the preset threshold, at this time, the sharp peak current cannot be completely inhibited by the current limiting unit alone, and therefore the absorption circuit is needed to absorb the sharp peak current, at this time, the relay K2 is closed to connect the absorption circuit to the loop to absorb the sharp peak current;

[0075] 5, then close the main loop relay K1, at this time, the sharp peak current is generated and absorbed by the capacitor C1;

[0076] This case corresponds to the case that the current limiting unit cannot completely inhibit the sharp peak current, after the relay K2 is closed, the absorption circuit is connected to the loop, and then the relay K1 is closed, at this time, the sharp peak current can be absorbed by the capacitor C1 in the absorption circuit;

[0077] 6, finally, the resistance value of the adjustable resistor is slowly reduced to 0, and the DC front and rear ends are connected;

[0078] This case corresponds to the case that the power supply works stably, at this time, the circuit does not generate sharp peak current, in order to avoid energy waste caused by high power consumption of the current limiting resistor, the resistance value of the current limiting unit needs to be adjusted to the minimum, that is, reduced to 0 in the above.

[0079] The utility model discloses through above-mentioned process has completed the inhibition of sharp peak current, avoided the occurrence of main relay sticking failure.

[0080] Further, the utility model also provides a kind of electric equipment, which has the above-mentioned front end anti-sticking protection circuit.

[0081] Compared with the prior art, the utility model has at least the following beneficial effects:

[0082] 1. The utility model discloses a current -limiting circuit, this current -limiting circuit is connected between power supply front end and power supply rear end, and the resistance value of current -limiting circuit is at the maximum when power supply power is on, can produce the good inhibitory effect to the spike current of this time, avoid the influence of spike current to relay, appear the problem of sticking failure;

[0083] 2. The utility model discloses in power supply power work stability, set the resistance value of current -limiting unit is at the minimum, can reduce the loss of current -limiting unit to whole loop;

[0084] 3. The utility model discloses still be provided with the absorption circuit, can when the voltage difference between power supply front end and power supply rear end exceeds the preset threshold, further absorption produces the spike current, avoid the sticking failure of relay, greatly improve the life and use security of relay.

[0085] The above only is the preferred embodiment of the utility model, and does not limit the utility model, and any modification, equivalent replacement and improvement etc. in the spirit and principle of the utility model are included in the protection scope of the utility model.

Claims

1. A front end anti-sticking protection circuit comprising a relay connected between a power supply front end and a power supply back end of a power supply, characterized in that, The power supply further comprises a current-limiting circuit connected between the front end and the back end, the current-limiting circuit having at least one current-limiting unit with adjustable resistance, the resistance of the current-limiting unit being at a maximum when the power supply is powered on and at a minimum when the power supply is stable.

2. The front-end anti-stiction protection circuit of claim 1, wherein, The power supply further comprises a detection unit connected to the front end and the back end respectively, and an absorption circuit connected between the front end and the back end. The detection unit is configured to detect a voltage parameter of the front end and the back end, and the absorption circuit is configured to be turned on to absorb a sharp current between the front end and the back end when the voltage parameter exceeds a preset threshold.

3. The front-end anti-stickzation protection circuit of claim 2, wherein, The power supply has a first front end, a second front end, a first back end, and a second back end. The first front end is connected to the first back end, the second front end is connected to the second back end, and the connection line between the first front end and the first back end is connected to the connection line between the second front end and the second back end.

4. The front-end anti-sticking protection circuit of claim 3, wherein, The relay is connected in series between the first front end and the first back end, and the current-limiting unit is connected in series between the second front end and the second back end.

5. The front-end anti-sticking protection circuit of claim 3, wherein, The absorption circuit comprises a first resistor, a first capacitor, and a switching switch, one end of the first resistor is connected between the first front end and the first back end, the other end of the first resistor is connected to one end of the first capacitor, the other end of the first capacitor is connected to one end of the switching switch, and the other end of the switching switch is connected between the second front end and the second back end.

6. The front-end anti-sticking protection circuit of claim 5, wherein, The absorption circuit further comprises a bleeder resistor connected in parallel across the first capacitor.

7. The front-end anti-sticking protection circuit of claim 5, wherein, The absorption circuit further comprises an anti-reverse connection diode, the negative electrode of the anti-reverse connection diode is connected between the first front end and the first back end, and the positive electrode of the anti-reverse connection diode is connected between the first resistor and the first capacitor.

8. The front-end anti-stickzation protection circuit of claim 1, wherein, The current-limiting unit is an adjustable resistor.

9. The front end anti-stickzation protection circuit of claim 5, wherein, The switching switch is a relay.

10. An electric device, characterized by The power-consuming device has a front-end anti-sticking protection circuit as claimed in any one of claims 1 to 9.

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