WO2021147587A1 - Surge absorbing circuit for three-phase air conditioning system - Google Patents

Abstract

The present invention relates to a circuit structure for a three-phase air conditioning system, specifically to a surge absorbing circuit for the three-phase air conditioning system, aiming at solving the technical problem of how to improve a surge absorbing circuit for a three-phase air conditioning system so as to improve the effective performance of resisting a surge high voltage of several thousand volts for multiple times. For this purpose, the present invention comprises the following structure: a first phase line, a second phase line, a third phase line, a zero line, and a first surge absorbing unit, the first surge absorbing unit comprising a loop formed by a first varistor and a first discharge tube that are connected in series between the first phase line and the zero line. In the present invention, the use of adding a structure of a varistor and a discharge tube between a phase line and a zero line improves absorption and withstand capabilities of a surge absorbing circuit to voltage, so as to ensure normal use of a three-phase air conditioning system.

Description

Surge absorption circuit for three-phase air conditioning system Technical field

The invention relates to the circuit structure of a three-phase air-conditioning system, in particular to a surge absorption circuit used in a three-phase air-conditioning system.

Background technique

With the continuous development of technology and the improvement of people's living standards, air conditioners have become an indispensable electrical product in people's daily work and life. Air conditioners are classified into three-phase air conditioners and single-phase air conditioners according to different power supply modes. Among them, single-phase air conditioners use 220V AC power supply, and three-phase air conditioners use 380V industrial power. Therefore, single-phase air conditioners are mostly used for family life with lower power, while three-phase air conditioners are mostly used for higher power and are mostly used in commercial places.

Because air conditioners, especially three-phase electric air conditioners, face different usage environments during actual use, especially thunderstorms in summer, which will have a huge impact on the service life of the air conditioner, the air conditioner will simulate the actual situation during the finished product inspection process. The application of lightning strikes and grid voltage spikes and surge tests. Normally, the voltage value of the surge test is 6000V. Such a high voltage often causes damage to the rectifier bridge and discharge tube in the three-phase electric air-conditioning circuit.

Fig. 1 is a structural diagram of a surge absorption circuit used in a three-phase air conditioning system in the prior art. As shown in Figure 1, L ₁ , L ₂ , and L ₃ are the three phase wires used by the three-phase air conditioning system, N is the neutral wire, and E ₁ , E ₂ , and E ₃ are the ground wires. Among them, the common mode inductor includes the first common mode coil l ₁ and the second common mode coil l _2. In normal use, the two common mode coils can cancel each other's magnetic field effect between the coils; when the common mode current flows in, it appears High impedance and strong damping effect. At this time, once a surge voltage is generated, according to the formula: U=L*di/dt, L is the inductance, and di/dt represents the derivative of current with respect to time, then voltage spikes will be generated on both sides of the common-mode inductance, which affects the rear rectifier bridge (Not shown in the picture) causing damage. At this time, the protection circuit in the circuit adopts the varistors R ₁ , R ₂ and R ₃ connected in series between the three phase lines and the neutral line, respectively, and the voltage between the neutral line N and the ground line E _{3 connected in series.} The sensitive resistor R ₄ and the discharge tube D _{1 are} connected in series, which in turn plays the role of voltage stabilization and voltage limitation. However, in the test process, multiple surge tests are still extremely easy to cause damage to the protection circuit and the rectifier bridge.

Correspondingly, a new surge absorbing circuit of a three-phase air conditioning system is needed in the art to solve the above-mentioned problems.

Summary of the invention

In order to solve the above-mentioned problems in the prior art, that is, to solve the technical problem of how to improve the surge absorption circuit of the three-phase air-conditioning system to improve the effective performance of resisting several thousand volts surge and high voltage, the present invention provides a three-phase air conditioning system. Surge absorption circuit of phase air conditioning system, including:

The first phase line, the second phase line, the third phase line, and the neutral line; the surge absorption circuit further includes: a first surge absorption unit;

The first surge absorbing unit includes: a loop formed by a first varistor and a first discharge tube connected in series between the first phase line and the neutral line.

The first surge absorbing unit further includes: a loop formed by a second varistor and a second discharge tube connected in series between the second phase line and the neutral line, and in series connected with the first A loop formed by a third varistor and a third discharge tube between the three-phase line and the neutral line.

In the above-mentioned preferred embodiment of the surge absorbing circuit for a three-phase air conditioning system, the surge absorbing circuit further includes: a second surge absorbing unit; the second surge absorbing unit includes: one end connected to the ground The other end of the fourth discharge tube is connected to the neutral line to form a loop.

In the foregoing preferred embodiment of the surge absorption circuit for a three-phase air conditioning system, the second surge absorption unit further includes:

The other end of the fourth discharge tube is connected in series with a fourth varistor and then connected to the neutral line, and the other end of the fourth discharge tube is connected in series with a fifth varistor and then connected to the third phase line, The other end of the fourth discharge tube is connected in series with a sixth varistor and then connected to the second phase line, and the other end of the fourth discharge tube is connected in series with a seventh varistor after being connected to the first phase line. Phase connection.

In the above-mentioned preferred embodiment of the surge absorption circuit for a three-phase air conditioning system, the fourth discharge tube is a ceramic discharge tube; and/or, the fourth varistor, the fifth varistor, At least one of the sixth varistor and the seventh varistor is a 10D471 type varistor.

In the above-mentioned preferred embodiment of the surge absorption circuit for a three-phase air conditioning system, at least one of the first varistor, the second varistor, and the third varistor is a 20D471 type varistor resistance.

In the above-mentioned preferred embodiment of the surge absorption circuit for the three-phase air conditioning system, it further includes: a third surge absorption unit;

The third surge absorbing unit includes: a fifth discharge tube and an eighth varistor connected in series between the first phase line and the second phase line; and in series connected with the first phase line and The sixth discharge tube and the ninth varistor between the third phase line are sequentially connected in series with the seventh discharge tube and the tenth varistor between the second phase line and the third phase line.

In the above-mentioned preferred embodiment of the surge absorption circuit for a three-phase air conditioning system, the first discharge tube, the second discharge tube, the third discharge tube, the fifth discharge tube, and the first discharge tube At least one of the six discharge tubes and the seventh discharge tube is a novel open-circuit failure gas discharge tube.

In the preferred embodiment of the surge absorption circuit for the three-phase air conditioning system, it further includes: a common mode inductor; the common mode inductor includes a first common mode coil and a second common mode coil connected in series; The first common mode coil is connected to the first phase line, the second phase line, the third phase line, and the neutral line respectively; the second common mode coil is connected to the rectifier bridge of the three-phase air conditioning system; common mode A noise absorbing unit, the common mode noise absorbing unit is connected between the first common mode coil and the second common mode coil.

In addition, the present invention also provides a three-phase air-conditioning system, the three-phase air-conditioning system includes the surge absorption circuit according to any one of the above solutions.

Those skilled in the art can understand that by connecting the first discharge tube and the first varistor in series with each other and then connecting between the first phase line and the neutral line, and connecting the second discharge tube and the second varistor in series with each other The first surge absorbing unit formed between the second phase line and the neutral line, the third discharge tube and the third varistor are connected in series with each other, and then connected between the third phase line and the neutral line. The invented surge absorption circuit makes full use of the respective advantages of voltage-stabilization and voltage-limiting of varistors and discharge tubes, and improves the absorption and tolerance of each item in the three-phase air-conditioning system to several thousand volts of surge voltage, regardless of actual use It also showed particularly stable performance in the surge test. In the specific surge test link, each phase in the circuit of the present invention has withstood more than 30 lightning strike tests, and there is no problem of damage to the rectifier bridge or the discharge tube.

In addition, the present invention also includes a second surge absorbing unit, which includes a fourth varistor, a fifth varistor, a sixth varistor, a seventh varistor, and a fourth discharge tube. The second surge The absorption unit further improves the ability to absorb and withstand surge voltages of several thousand volts. In the actual surge test link, the surge absorption unit can withstand 120 lightning strike tests and can ensure the normal use of the circuit.

Further, the present invention also includes a third surge absorbing unit, which includes a fifth discharge tube, a sixth discharge tube, a seventh discharge tube, and an eighth varistor, a ninth varistor, and a tenth varistor. While the surge absorption unit further ensures the stable operation of the surge absorption circuit, it can also reduce the residual pressure between phases in the three-phase air conditioning system, thereby ensuring the normal use of the three-phase air conditioning.

Description of the drawings

The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

Fig. 1 is a structural diagram of a surge absorption circuit used in a three-phase air conditioning system in the prior art.

Fig. 2 is a structural diagram of a preferred embodiment of a surge absorption circuit for a three-phase air conditioning system according to the present invention.

Figures 3, 4, and 5 are structural diagrams of other three preferred embodiments of a surge absorption circuit for a three-phase air conditioning system according to the present invention.

Detailed ways

The preferred embodiments of the present invention will be described below with reference to the drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention, and are not intended to limit the protection scope of the present invention. For example, although the preferred embodiment of the present invention is described in conjunction with the surge test, this is not restrictive. The technical solution of the present invention can obviously be used as a test circuit or as a circuit in actual use. This adjustment does not deviate from the basic principle of the present invention, and therefore will also fall within the protection scope of the present invention.

It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right" and other terms indicating the direction or position relationship are based on the direction or position relationship shown in the drawings. It is for the convenience of description, rather than indicating or implying that the device or element must have a specific orientation, be configured and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second" and other ordinal numbers are only used to distinguish several technical features of the same nature, and cannot be understood as indicating or implying relative importance.

In addition, it should be noted that in the description of the present invention, unless otherwise clearly defined and limited, the terms "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. , Or integrally connected; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication between two components. For those skilled in the art, the specific meaning of the above-mentioned terms in the present invention can be understood according to specific circumstances.

First, refer to FIG. 2, which is a structural diagram of an embodiment of a surge absorption circuit for a three-phase air conditioning system according to the present invention. Preferably, as shown in FIG. 2, the surge absorption circuit includes: a first phase line L ₁ , a second phase line L ₂ , a third phase line L ₃ and a neutral line N. In an example, the phase wire of the household electrical appliance may be a live wire. Wherein, the surge absorption circuit further includes: a first surge absorption unit 1; the first surge absorption unit 1 includes a first discharge tube DSA ₁ , a first varistor DNZ ₁ , a second discharge tube DSA ₂ , and a second The varistor DNZ ₂ , the third discharge tube DSA ₃ and the third varistor DNZ ₃ .

Wherein the first phase line L ₁ is connected to a first end of the first varistor DNZ _1, the second end of the first varistor DNZ a first end connected to _a first discharge tube ₁ of the DSA, the first discharge tube The second end of the DSA ₁ is connected to the neutral line N, thereby forming a _{loop of the first phase line L 1} -the first varistor DNZ ₁ -the first discharge tube DSA ₁ -the neutral line N. Similarly the second phase line L ₂ is electrically connected to the first end of the second varistor DNZ _2, the second end of the second varistor DNZ ₂ is electrically connected to a first end of a second discharge tube ₂ of the DSA, the second The second end of the discharge tube DSA ₂ is electrically connected to the neutral line N, thereby forming a _{loop of the second phase line L 2} -the second varistor DNZ ₂ -the second discharge tube DSA ₂ -the neutral line N. The third line L ₃ with a first end connected to the third ₃ DNZ varistor, the varistor third DNZ second end ₃ of the third discharge tube ₃ is connected to a first end of DSA, DSA third discharge tube ₃ The second end of is connected to the neutral line N, thereby forming a _{loop of the third phase line L 3} — the third varistor DNZ ₃ — the third discharge tube DSA ₃ — the neutral line N.

Furthermore, during the test, the surge protection circuit of the present invention also includes a common mode inductor 2. The common mode inductor 2 includes a first common mode coil 21 and a second common mode coil 22 connected in series; The mode coil 21 is respectively connected to the first phase line L ₁ , the second phase line L ₂ , the third phase line L ₃ , and the neutral line N; the second common mode coil 22 is connected to the rectifier bridge of the three-phase air conditioning system (not shown in the figure) show).

Specifically, the first common mode coil 21 includes a first inductor 211, a second inductor 212, a third inductor 213, and a fourth inductor 214. Wherein an end of the first inductor 211 and the third line L ₃ phase connection; end of the second inductor 212 is connected to a second phase line L _2; end of the third inductor 213 and the first phase line L _1; fourth inductor 214 One end of is connected to the neutral line N. The second common mode coil 22 includes a fifth inductor 221, a sixth inductor 222, a seventh inductor 223, and an eighth inductor 224. One end of the fifth inductor 221 is connected to the other end of the first inductor 211; one end of the sixth inductor 222 is connected to the other end of the second inductor 212; one end of the seventh inductor 223 is connected to the other end of the third inductor 213; One end of the eight inductor 224 is connected to the other end of the fourth inductor 214. Further, the other end of the fifth inductor 221, the other end of the sixth inductor 222, the other end of the seventh inductor 223 and the other end of the eighth inductor 224 will be connected to different rectifier bridges for rectification (not shown in the figure), No more details here.

In the actual test process, the surge absorbing circuit also includes a common mode noise absorbing unit 3, and the common mode noise absorbing unit 3 is connected between the first common mode coil 21 and the second common mode coil 22. Specifically, the common mode noise absorption unit 3 includes a first Y capacitor 31, a second Y capacitor 32, a third Y capacitor 33, and a fourth Y capacitor 34. One end of the first Y capacitor 31 is connected to one end of the fifth inductor 221 and the other end of the first inductor 211; one end of the second Y capacitor 32 is connected to one end of the sixth inductor 222 and the other end of the second inductor 212; One end of the three Y capacitor 33 is connected to one end of the seventh inductor 223 and the other end of the third inductor 213; one end of the fourth Y capacitor 34 and one end of the eighth inductor 224 are connected to the other end of the fourth inductor 214. The other end of the first Y and second Y-capacitor 31 and the other end of the capacitor 32 are connected to the ground E _1, the other end of the third capacitor 33 and fourth Y Y capacitor and the other end connected to the ground E ₂ 34. The common mode noise absorbing unit 3 is added between the common mode inductors 2 to effectively eliminate the common mode noise generated by the current in the same direction. A better grounding effect can be achieved by using different ground wires E ₁ and E _{2 connection methods.}

Among them, Y capacitors are safety capacitors, they are capacitors used in this kind of occasions, that is, after the capacitor fails, it will not cause electric shock and will not endanger personal safety. Specifically, the Y capacitor is a capacitor connected across the phase line and the ground line and the ground respectively. Due to the limitation of leakage current, the Y capacitor value cannot be too large, and the Y capacitor is generally nF. The Y capacitor suppresses common mode interference.

It should be noted that although the connection relationship between each inductor and the phase line and the inductor is described above, this is not restrictive, and those skilled in the art can adjust the connection relationship as needed.

In one particular embodiment, the surge protection circuit according to the present invention further comprises a second surge absorption unit 4, comprising a fourth discharge tube ₄ the DSA, the DSA and the fourth discharge tube ₄ at one end to the other end of the series connection of the ground line PE _{The fourth varistor DNZ 4} between and the neutral line N, the fifth varistor DNZ ₅ connected in series between the other end of the fourth discharge tube DSA ₄ and the third phase line L ₃ , connected in series with the fourth discharge tube DSA ₄ and the other end of the second line L between the sixth DNZ varistor ₂₆ connected in series and the other end of the fourth discharge tube ₄ and the DSA seventh DNZ varistor between L ₁ of the first phase line _7. Furthermore, when any one of the three phase lines, for example, the first phase line L ₁ generates a surge voltage, the seventh varistor DNZ ₇ and the fourth discharge tube DSA ₄ can be used to stabilize and limit the voltage.

It should be noted here that during the surge test, the fourth discharge tube DSA ₄ needs to perform 30 lightning strike tests for the three phase lines and the neutral line, and the total will reach 120 times. The fourth discharge tube DSA ₄ The use of ceramic discharge tubes can increase its resistance to lightning strikes. At the same time, _{at least one of the fourth varistor DNZ 4} , the fifth varistor DNZ ₅ , the sixth varistor DNZ ₆ and the seventh varistor DNZ ₇ is a 10D471 type varistor. This varistor has better surge absorption capability, and therefore is more suitable for use in the surge absorption circuit of the present invention. Similarly, the fourth varistor DNZ ₄ , the fifth varistor DNZ ₅ , the sixth varistor DNZ ₆ and the seventh varistor DNZ ₇ can also be 10D561 type varistors. The difference between the two is mainly the difference in the voltage limit, the 10D471 type varistor is 470V, and the 10D561 type varistor is 560V.

What needs to be added here is that at least one of the _{first varistor DNZ 1} , the second varistor DNZ ₂ and the third varistor DNZ _{3 is a 20D471 type varistor.} Compared with 10D471 type varistor, it can withstand higher current. In this regard, those skilled in the art can also set one or part (but not all) of the above-mentioned varistors to the above-mentioned model, or set one (but not all) of the above-mentioned discharge tubes to the above-mentioned model, as required. Alternatively, the above-mentioned varistor or discharge tube can be set to other models suitable for surge absorption circuits. This adjustment does not deviate from the basic principle of the present invention, and therefore all fall within the protection scope of the present invention.

Continuing to refer to FIG. 2, the surge absorbing circuit of the present invention further includes a third surge absorbing unit 5; the third surge absorbing unit 5 includes a first phase line L ₁ and a second phase line L ₂ connected in series. DSA ₅ the discharge tube and the eighth five varistor DNZ ₈ (eg: a first phase line L ₁ connecting the fifth end of the discharge tube DSA _5, the fifth discharge tube DSA ₅ connected to one end of the other end of the varistor DNZ ₈ of the eighth, The other end of the eighth varistor DNZ ₈ is connected to the second phase line L ₂ ); the sixth discharge tube DSA ₆ and the ninth varistor are sequentially connected in series between the first phase line L ₁ and the third phase line L ₃ DNZ ₉ (for example: a first phase line L ₁ connecting one end of the sixth discharge tube DSA _6, the sixth discharge tube DSA ₆ other end is connected one end of a ninth resistor DNZ _9, the other end of the ninth resistor DNZ ₉ is connected to a third phase line L ₃ ); The seventh discharge tube DSA ₇ and the tenth varistor DNZ ₁₀ connected in series between the second phase line L ₂ and the third phase line L ₃ (for example: the second phase line L _{2 is} connected to the seventh discharge DSA ₇ pipe end, the other end of the seventh discharge DSA ₇ connected to one end of the tenth resistor DNZ _10, the other end of the tenth resistor DNZ ₁₀ is connected to a third phase line L _3). Specifically, after the surge test, residual voltage will appear between the three phase wires. The series structure of the discharge tube and the varistor connected in series between the phase wires can effectively reduce the residual voltage, and can also prevent the varistor from being left due to residual voltage. Damage caused by pressure. In actual use _{, at least one of the eighth varistor DNZ 8} , the ninth varistor DNZ ₉ and the tenth varistor DNZ ₁₀ is a 20D621 type varistor with a voltage limit value of 620V.

The first surge absorbing unit includes: a loop formed by _{a first varistor DNZ 1} and a first discharge tube DSA ₁ connected in series between the first phase line and the neutral line. What needs to be added here is that among the discharge tubes used in the surge protection circuit of the present invention, the fourth discharge tube DSA ₄ is preferably a gas discharge tube, and the first discharge tube DSA ₁ , the second discharge tube DSA ₂ , and the third The discharge tube DSA ₃ , the fifth discharge tube DSA ₅ , the sixth discharge tube DSA ₆ and the seventh discharge tube DSA _{7 are} preferably novel open-circuit failure gas discharge tubes. The difference is that the new type of open circuit failure gas discharge tube has a larger withstand voltage resistance, which can effectively prevent the varistor in series from being damaged due to high-pressure combustion. The fourth discharge tube DSA _{4 is} connected to the three phase lines L _1. Between L ₂ , L ₃ , the neutral wire N and the ground wire PE, the AC voltage of about 1850V will withstand, so the gas discharge tube can better withstand the high voltage.

An example of a test scenario is: the third surge absorbing unit 5 between the three-phase lines uses a 621 pressure sensitive string 1000V OGDT (new open-circuit failure gas discharge tube), and the withstand voltage fluctuation can reach about AC600V on the line, while reducing the phase and phase. OGDT in series can effectively prevent pressure-sensitive fires. The first surge absorption unit 1 between the phase line and the neutral line N uses a 471 pressure sensitive string 600V OGDT. The second surge absorbing unit 4 between the phase line, neutral line N and PE uses 471/561 pressure sensitive series connection with 3600V GDT (gas discharge tube), which can be used to withstand AC1 850V, 3600V GDT lightning (surge) Impact) 120 times, because the 3600V GDT may have the risk that the voltage waveform cannot meet the AC withstand voltage after 120 lightning strikes, if you want to increase the number of lightning strikes, use B5G3600-C to withstand the number of times better.

Next, in conjunction with FIGS. 3, 4, and 5, the structure diagrams of several other preferred simplified circuit embodiments of the surge absorption circuit used in the three-phase air conditioning system according to the present invention will be described. Among them, the circuit is simplified and changed on the basis of FIG. 2, and the parts of the same content as shown in FIG. 2 in each embodiment will not be repeated.

One of the preferred embodiments of the simplified structure, as shown in FIG. 3, the second surge absorbing unit 4 is simplified to include: a fourth discharge tube DSA ₄ with one end connected to the ground PE, and the other end of the fourth discharge tube DSA ₄ Connect with the neutral line N to form a loop. In this way, since there is usually no voltage difference between the neutral line N and the ground line PE, only the fourth discharge tube DSA ₄ can be used when the surge voltage is generated, without the need for a varistor to close the arc. In an example of a test scenario, the third surge absorbing unit 5 shown in Figure 2 is maintained between the three-phase lines; the first surge absorbing unit 1 shown in Figure 2 is maintained between the three-phase line and the neutral line N Refer to the single-item AC220V test; the simplified second surge absorbing unit 4 of the three-phase line and the neutral line N to the ground PE, test the surge, through the varistor and GDT in the first surge absorbing unit 1, Then to 3600V GDT for venting, the device withstands 30 times of differential mode 3KA+30 times of common mode 500A surge.

The second preferred embodiment of the simplified structure, as shown in FIG. 4, the first surge absorbing unit 1 is simplified to include: a first discharge tube DSA ₁ , a first varistor DNZ ₁ , wherein the first phase line L ₁ a first end connected to the first varistor DNZ _1, the second end of the first varistor DNZ a first end connected to _a first discharge tube ₁ of the DSA, DSA second end of the first discharge tube ₁ is zero The line N is connected, thereby forming a _{loop of the first phase line L 1} -the first varistor DNZ ₁ -the first discharge tube DSA ₁ -the neutral line N. In an example of a test scenario, the second and third surge absorbing units 4 and 5 maintain the way shown in Figure 2. When the first surge absorbing unit 1 is tested, only the first phase line L _{1 is used in the subsequent circuit.} And the neutral line N, only _{use OGDT+MOV on the first phase line L 1} to the neutral line N to reduce the residual voltage; while the second and third phase lines L ₂ and L ₃ surge to the neutral line N pass The components of the third surge absorbing unit 5 are shared. _{The residual voltage of the second phase line L 2} to the neutral line N and the third phase line L ₃ to the neutral line N are relatively high, but it is also sufficient if the subsequent stage does not have a circuit directly connected. ; The pressure sensitive and OGDT between the second phase line L ₂ and the third phase line L _{3, and} between the second phase line L ₂ and the first phase line L ₁ must withstand 60 3KA lightning strikes (surges).

The third preferred embodiment of simplified structure, as shown in FIG. 5, the structure of the first surge absorbing unit 1 is simplified to include: a first discharge tube DSA ₁ , a first varistor DNZ ₁ , where the first phase line L DNZ varistor ₁ of the first terminal ₁ is connected to a first, a second end of the first varistor DNZ a first end connected to _a first discharge tube ₁ of the DSA, the DSA second end of the first discharge tube ₁ and The neutral line N is connected to form a _{loop of the first phase line L 1} -the first varistor DNZ ₁ -the first discharge tube DSA ₁ -the neutral line N; the structure of the second surge absorption unit 4 is simplified to include: _{The fourth discharge tube DSA 4 has} one end connected to the ground wire PE, and the other end of the fourth discharge tube DSA ₄ is connected to the neutral line N to form a loop. In an example of a test scenario, in conjunction with the aforementioned descriptions related to Figures 2, 3, _{and 4 , the device between the first phase line L 1} and the second phase line L 2 withstands 60 times of 3KA+30 times of 500A surges, and the first phase line The _{device between L 1} and the third phase line L ₃ withstands 60 3KA+30 times 500A surges, the device between the second phase line L ₂ and the third phase line L ₃ withstands 30 times 3KA surges, the first phase line The _{device between L 1} and the neutral line N withstands 90 times of 3KA+90 times of 500A surges, and the device between the neutral line N and the ground line PE withstands 120 times of 500A surges.

On the basis of the above-mentioned surge absorption circuit, the present invention also provides a three-phase air conditioning system. The three-phase air conditioning system includes the various surge absorption circuits described above. Correspondingly, the technical effect that can be obtained by the three-phase air conditioning system is the same as the above-mentioned surge absorption circuit, and will not be repeated here.

Finally, it should be noted that, in addition to the varistor, the specifications and models of other circuit components are not clear in the above description. However, those skilled in the art can understand that other circuit components, such as Y capacitors, resistors, The specific models and parameters of the discharge tube and the like can be reasonably selected by those skilled in the art according to the application or test scenario, especially the surge voltage amplitude that may be encountered, and the present invention does not impose any limitation on this.

So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims (10)

1. A surge absorption circuit used in a three-phase air conditioning system, including:

   The first phase line, the second phase line, the third phase line, and the neutral line; wherein the surge absorption circuit further includes: a first surge absorption unit;

   The first surge absorbing unit includes: a loop formed by a first varistor and a first discharge tube connected in series between the first phase line and the neutral line.
2. The surge absorbing circuit for a three-phase air conditioning system according to claim 1, wherein the first surge absorbing unit further comprises: sequentially connecting in series between the second phase line and the neutral line The loop formed by the second varistor and the second discharge tube, and the loop formed by the third varistor and the third discharge tube connected in series between the third phase line and the neutral line.
3. The surge absorption circuit for a three-phase air conditioning system according to claim 2, wherein the surge absorption circuit further comprises:

   The second surge absorption unit;

   The second surge absorbing unit includes: a fourth discharge tube with one end connected to the ground line, and the other end of the fourth discharge tube is connected with the neutral line to form a loop.
4. The surge absorbing circuit for a three-phase air conditioning system according to claim 2, wherein the second surge absorbing unit further comprises:

   The other end of the fourth discharge tube is connected in series with a fourth varistor and then connected to the neutral line, and the other end of the fourth discharge tube is connected in series with a fifth varistor and then connected to the third phase line, The other end of the fourth discharge tube is connected in series with a sixth varistor and then connected to the second phase line, and the other end of the fourth discharge tube is connected in series with a seventh varistor after being connected to the first phase line. Phase connection.
5. The surge absorption circuit for a three-phase air conditioning system according to claim 4, characterized in that:

   The fourth discharge tube is a ceramic discharge tube;

   and / or,

   At least one of the fourth varistor, the fifth varistor, the sixth varistor, and the seventh varistor is a 10D471 type varistor.
6. The surge absorption circuit for a three-phase air conditioning system according to claim 1, wherein at least one of the first varistor, the second varistor, and the third varistor is 20D471 type varistor.
7. The surge absorption circuit for a three-phase air conditioning system according to claim 1, characterized in that it further comprises:

   The third surge absorption unit;

   The third surge absorbing unit includes: a fifth discharge tube and an eighth varistor connected in series between the first phase line and the second phase line; and in series connected with the first phase line and The sixth discharge tube and the ninth varistor between the third phase line; the seventh discharge tube and the tenth varistor connected in series between the second phase line and the third phase line in sequence.
8. The surge absorption circuit for a three-phase air conditioning system according to claim 7, wherein: the first discharge tube, the second discharge tube, the third discharge tube, and the fifth discharge tube , At least one of the sixth discharge tube and the seventh discharge tube is a novel open-circuit failure gas discharge tube.
9. The surge absorption circuit for a three-phase air conditioning system according to claim 1, characterized in that it further comprises:

   A common mode inductor; the common mode inductor includes: a first common mode coil and a second common mode coil connected in series; the first common mode coil is connected to the first phase line and the second phase line respectively , The third phase line is connected with the neutral line; the second common mode coil is connected with the rectifier bridge of the three-phase air conditioning system; the common mode noise absorption unit;

   The common mode noise absorption unit is connected between the first common mode coil and the second common mode coil.
10. A three-phase air conditioning system, characterized by comprising the surge absorption circuit according to any one of claims 1 to 9.

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