A rectifier-type intrinsically safe Buck circuit

Abstract

The invention provides a rectifier-type intrinsically safe Buck circuit, comprising a main circuit and four limiting circuits. The main circuit comprises a power supply E, a switch tube S, a diode D, an inductor L, a capacitor C and a resistor R. The switch tube S is connected to the inductor L through a second circuit, the inductor L is connected to the resistor R through a third circuit, the resistor R is connected to the power supply E through a fourth circuit, the diode D is connected between the second circuit and the fourth circuit, the capacitor C is connected between the third circuit and the fourth circuit, the four limiting circuits are respectively connected to the first circuit, the second circuit, the third circuit and the fourth circuit, the circuit structure is simple, and through rectification of open-circuit sparks, capacitor suppression and diode voltage clamping, the circuit cannot form dangerous open-circuit sparks from beginning to end, and cannot form arcs at all, thereby improving the intrinsic safety performance of the circuit.

Description

Technical Field

[0001] The invention relates to the technical field of explosion-proof electrical safety, and in particular to a rectifier-type intrinsically safe Buck circuit. Background Art

[0002] Buck circuit is also called step-down circuit. Its basic characteristics are DC-DC conversion circuit, output voltage is lower than input voltage, output current is pulsating, and output current is continuous. When the switch tube in the Buck circuit is driven to a high level, the switch tube is turned on, the energy storage inductor is magnetized, and the current flowing through the inductor increases linearly, while charging the capacitor and providing energy to the load. When the switch tube in the Buck circuit is driven to a low level, the switch tube is turned off, the energy storage inductor is discharged through the freewheeling diode, the inductor current is linearly reduced, and the output voltage is maintained by the discharge of the output filter capacitor and the reduced inductor current.

[0003] Since the Buck circuit needs to meet the intrinsic safety performance when used in an explosive gas environment. The invention patent with application number ZL201410042878.1 provides an arc extinguishing method for an intrinsically safe inductor circuit. The intrinsically safe inductor circuit is composed of a power supply, a resistor and an inductor in series. The positive end of the power supply is electrically connected to the resistor through the first circuit, the resistor is electrically connected to the inductor through the second circuit, the inductor is electrically connected to the reverse end of the power supply through the third circuit, and the two ends of the inductor are reversely connected in parallel with a diode. The two ends of the first, second and third circuits are respectively connected in parallel with an arc extinguishing circuit, and each arc extinguishing circuit is electrically connected to the detection drive unit. The invention connects a diode and a MOS transistor in parallel at both ends of the circuit in a forward direction, so that the open circuit discharge spark cannot form the most dangerous arc discharge stage, and the discharge spark can be automatically extinguished, thereby improving the safety performance of the inductor circuit.

[0004] The intrinsically safe circuit in the above arc extinguishing method prevents the formation of open circuit sparks in the most dangerous arc discharge stage, thereby effectively extinguishing the arc. However, it is an arc extinguishing process after the dangerous open circuit sparks are generated, and the intrinsic safety performance of the circuit is low. Summary of the invention

[0005] In order to overcome the deficiency of low intrinsic safety performance of the circuit in the above-mentioned prior art, the present invention provides a rectifier-type intrinsically safe Buck circuit, which includes a main circuit and four limiting circuits. The main circuit includes a power supply, a switch tube, a diode, an inductor, a capacitor and a resistor, which can ensure that no dangerous open-circuit sparks are formed from beginning to end, and no arc is formed at all, thereby improving the intrinsic safety performance of the circuit.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical scheme:

[0007] The present invention provides a rectifier-type intrinsically safe Buck circuit, comprising a main circuit and a limiting circuit;

[0008] The main circuit includes a power supply E, a switch tube S, a diode D, an inductor L, a capacitor C and a resistor R, wherein the power supply E is connected to the switch tube S through a first line, the switch tube S is connected to the inductor L through a second line, the inductor L is connected to the resistor R through a third line, the resistor R is connected to the power supply E through a fourth line, the diode D is connected between the second line and the fourth line, and the capacitor C is connected between the third line and the fourth line;

[0009] The limiting circuit includes a first limiting circuit, a second limiting circuit, a third limiting circuit and a fourth limiting circuit, and the first limiting circuit, the second limiting circuit, the third limiting circuit and the fourth limiting circuit are respectively connected to a first line, a second line, a third line and a fourth line.

[0010] The positive electrode A1 of the power source E is connected to the drain electrode A3 of the switch tube S, and A1 and A3 form a first circuit.

[0011] The source A4 of the switch tube S is connected to the first end A7 of the inductor L, the cathode A5 of the diode D is connected to A4, and A4, A5 and A7 form a second circuit;

[0012] The second end A8 of the inductor L is connected to the first end A11 of the resistor R, and A8 is connected to the first end A9 of the capacitor C, and A8, A9 and A11 form a third circuit.

[0013] The second end A12 of the resistor R, the second end A10 of the capacitor C, and the anode A6 of the diode D are all connected to the negative electrode A2 of the power source E, and A2, A6, A10 and A12 form a fourth circuit.

[0014] The first limiting circuit includes a full-bridge rectifier circuit, a capacitor C1, a diode D5 and a diode D6;

[0015] The full-bridge rectifier circuit comprises a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm, wherein the first bridge arm, the second bridge arm, the third bridge arm and the fourth bridge arm are respectively provided with a diode D1, a diode D2, a diode D3 and a diode D4;

[0016] The anode of the diode D1 and the cathode of the diode D2 are both connected to the first output terminal B of the first limiting circuit, and the anode of the diode D3 and the cathode of the diode D4 are both connected to the second output terminal F of the first limiting circuit;

[0017] The cathodes of the diodes D1 and D3 are connected to a common point H, and the anodes of the diodes D2 and D4 are connected to a common point G;

[0018] The first end of the capacitor C1, the cathode of the diode D5 and the anode of the diode D6 are all connected to a common point H, and the second end of the capacitor C1, the anode of the diode D5 and the cathode of the diode D6 are all connected to a common point G;

[0019] The first output terminal B and the second output terminal F of the first limiting circuit are connected to the positive electrode A1 of the power source E and the drain electrode A3 of the switch tube S respectively.

[0020] The second limiting circuit includes a first three-phase bridge rectifier circuit, a capacitor C2, a diode D27 and a diode D28;

[0021] The first three-phase bridge rectifier circuit includes a fifth bridge arm, a sixth bridge arm, a seventh bridge arm, an eighth bridge arm, a ninth bridge arm and a tenth bridge arm, and the fifth bridge arm, the sixth bridge arm, the seventh bridge arm, the eighth bridge arm, the ninth bridge arm and the tenth bridge arm are respectively provided with a diode D21, a diode D22, a diode D23, a diode D24, a diode D25 and a diode D26;

[0022] The anode of the diode D21 and the cathode of the diode D22 are both connected to the first output terminal I of the first three-phase bridge rectifier circuit, the anode of the diode D23 and the cathode of the diode D24 are both connected to the second output terminal J of the first three-phase bridge rectifier circuit, and the anode of the diode D25 and the cathode of the diode D26 are both connected to the third output terminal K of the first three-phase bridge rectifier circuit;

[0023] The cathodes of the diodes D21, D23 and D25 are all connected to a common point M, and the cathodes of the diodes D22, D24 and D25 are all connected to a common point N;

[0024] The first end of the capacitor C2, the cathode of the diode D27 and the anode of the diode D28 are all connected to a common point M, and the second end of the capacitor C2, the anode of the diode D27 and the cathode of the diode D28 are all connected to a common point N;

[0025] The first output terminal I, the second output terminal J and the third output terminal K of the first three-phase bridge rectifier circuit are connected to the first end A7 of the inductor L, the cathode A5 of the diode D and the source A4 of the switch tube S respectively.

[0026] The third limiting circuit includes a second three-phase bridge rectifier circuit, a capacitor C3, a diode D37 and a diode D38;

[0027] The second three-phase bridge rectifier circuit includes an eleventh bridge arm, a twelfth bridge arm, a thirteenth bridge arm, a fourteenth bridge arm, a fifteenth bridge arm and a sixteenth bridge arm, and the eleventh bridge arm, the twelfth bridge arm, the thirteenth bridge arm, the fourteenth bridge arm, the fifteenth bridge arm and the sixteenth bridge arm are respectively provided with a diode D31, a diode D32, a diode D33, a diode D34, a diode D35 and a diode D36;

[0028] The anode of the diode D31 and the cathode of the diode D32 are both connected to the first output terminal O of the second three-phase bridge rectifier circuit, the anode of the diode D33 and the cathode of the diode D34 are both connected to the second output terminal P of the second three-phase bridge rectifier circuit, and the anode of the diode D35 and the cathode of the diode D36 are both connected to the third output terminal Q of the second three-phase bridge rectifier circuit;

[0029] The cathodes of the diodes D31, D33 and D35 are all connected to a common point T, and the cathodes of the diodes D32, D34 and D35 are all connected to a common point U;

[0030] The first end of the capacitor C3, the cathode of the diode D37 and the anode of the diode D38 are all connected to a common point T, and the second end of the capacitor C2, the anode of the diode D37 and the cathode of the diode D38 are all connected to a common point U;

[0031] The first output terminal O, the second output terminal P and the third output terminal Q of the second three-phase bridge rectifier circuit are connected to the first end A11 of the resistor R, the first end A9 of the capacitor C and the second end A8 of the inductor L respectively.

[0032] The fourth limiting circuit includes a four-arm bridge rectifier circuit, a capacitor C4, a diode D49 and a diode D50;

[0033] The four-bridge-arm bridge rectifier circuit includes a seventeenth bridge arm, an eighteenth bridge arm, a nineteenth bridge arm, a twentieth bridge arm, a twenty-first bridge arm and a twenty-second bridge arm, and the seventeenth bridge arm, the eighteenth bridge arm, the nineteenth bridge arm, the twentieth bridge arm, the twenty-first bridge arm and the twenty-second bridge arm are respectively provided with a diode D41, a diode D42, a diode D43, a diode D44, a diode D45, a diode D46, a diode D47 and a diode D48;

[0034] The anode of the diode D41 and the cathode of the diode D42 are both connected to the first output terminal V of the four-arm bridge rectifier circuit, the anode of the diode D43 and the cathode of the diode D44 are both connected to the second output terminal W of the four-arm bridge rectifier circuit, the anode of the diode D45 and the cathode of the diode D46 are both connected to the third output terminal X of the four-arm bridge rectifier circuit, and the anode of the diode D47 and the cathode of the diode D48 are both connected to the fourth output terminal Y of the four-arm bridge rectifier circuit;

[0035] The cathodes of the diodes D41, D43, D45 and D47 are all connected to a common point Z, and the cathodes of the diodes D42, D44, D46 and D48 are all connected to a common point A;

[0036] The first end of the capacitor C4, the cathode of the diode D49 and the anode of the diode D50 are all connected to a common point Z, and the second end of the capacitor C4, the anode of the diode D49 and the cathode of the diode D50 are all connected to a common point A;

[0037] The first output terminal V, the second output terminal W, the third output terminal Z and the fourth output terminal Y of the four-arm bridge rectifier circuit are respectively connected to the second end A12 of the resistor R, the second end A10 of the capacitor C, the anode A6 of the diode D and the cathode A2 of the power supply E.

[0038] Compared with the closest prior art, the technical solution provided by the present invention has the following beneficial effects:

[0039] The rectifier intrinsically safe Buck circuit provided by the present invention comprises a main circuit and four limiting circuits. The main circuit comprises a power supply E, a switch tube S, a diode D, an inductor L, a capacitor C and a resistor R. The switch tube S is connected to the inductor L through a second line, the inductor L is connected to the resistor R through a third line, the resistor R is connected to the power supply E through a fourth line, the diode D is connected between the second line and the fourth line, the capacitor C is connected between the third line and the fourth line, the four limiting circuits are respectively connected to the first line, the second line, the third line and the fourth line, the circuit structure is simple, and through the rectification of the open-circuit spark, the capacitor suppression and the diode voltage clamping, the circuit cannot form a dangerous open-circuit spark from the beginning to the end, and cannot form an arc at all, thereby improving the intrinsic safety performance of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a structural diagram of a rectifier intrinsically safe Buck circuit in Embodiment 1 of the present invention;

[0041] Figure 2 This is a schematic diagram of the arc extinguishing principle of the rectifier-type intrinsically safe Buck circuit in Embodiment 2 of the present invention;

[0042] Figure 3 This is a schematic diagram of the arc extinguishing principle of the rectifier-type intrinsically safe Buck circuit in Embodiment 3 of the present invention;

[0043] Figure 4 This is a schematic diagram of the arc extinguishing principle of the rectifier-type intrinsically safe Buck circuit in Embodiment 4 of the present invention;

[0044] Figure 5 It is a schematic diagram of the arc extinguishing principle of the rectifier intrinsically safe Buck circuit in Example 5 of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0046] Example 1

[0047] Embodiment 1 of the present invention provides a rectifier-type intrinsically safe Buck circuit, the specific structure diagram of which is shown in FIG. Figure 1 As shown, it includes a main circuit and a limiting circuit;

[0048] The main circuit includes a power supply E, a switch tube S, a diode D, an inductor L, a capacitor C and a resistor R. The power supply E is connected to the switch tube S through a first line, the switch tube S is connected to the inductor L through a second line, the inductor L is connected to the resistor R through a third line, the resistor R is connected to the power supply E through a fourth line, the diode D is connected between the second line and the fourth line, and the capacitor C is connected between the third line and the fourth line;

[0049] The limiting circuit includes a first limiting circuit, a second limiting circuit, a third limiting circuit and a fourth limiting circuit, which are connected to the first line, the second line, the third line and the fourth line respectively.

[0050] The positive electrode A1 of the power source E is connected to the drain electrode A3 of the switch tube S, and A1 and A3 form a first circuit.

[0051] The source A4 of the switch tube S is connected to the first end A7 of the inductor L, the cathode A5 of the diode D is connected to A4, and A4, A5 and A7 form a second circuit.

[0052] The second end A8 of the inductor L is connected to the first end A11 of the resistor R, and A8 is connected to the first end A9 of the capacitor C, and A8, A9 and A11 form a third circuit.

[0053] The second end A12 of the resistor R, the second end A10 of the capacitor C, and the anode A6 of the diode D are all connected to the negative electrode A2 of the power source E, and A2, A6, A10 and A12 form a fourth circuit.

[0054] The first limiting circuit, the second limiting circuit, the third limiting circuit and the fourth limiting circuit are described in detail below:

[0055] 1. The first limiting circuit includes a full-bridge rectifier circuit, a capacitor C1, a diode D5 and a diode D6;

[0056] The function of the full-bridge rectifier circuit is to charge the capacitor C1 regardless of the input voltage polarity. The function of C1 is to suppress the sudden change of the spark voltage at the open circuit. The function of D5 and D6 is voltage clamping.

[0057] The full-bridge rectifier circuit includes a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm, and the first bridge arm, the second bridge arm, the third bridge arm and the fourth bridge arm are respectively provided with a diode D1, a diode D2, a diode D3 and a diode D4;

[0058] The anode of the diode D1 and the cathode of the diode D2 are both connected to the first output terminal B of the first limiting circuit, and the anode of the diode D3 and the cathode of the diode D4 are both connected to the second output terminal F of the first limiting circuit;

[0059] The cathodes of the diodes D1 and D3 are connected to a common point H, and the anodes of the diodes D2 and D4 are connected to a common point G;

[0060] The first end of the capacitor C1, the cathode of the diode D5 and the anode of the diode D6 are all connected to a common point H, and the second end of the capacitor C1, the anode of the diode D5 and the cathode of the diode D6 are all connected to a common point G;

[0061] The first output terminal B and the second output terminal F of the first limiting circuit are connected to the positive electrode A1 of the power source E and the drain electrode A3 of the switch tube S respectively.

[0062] 2. The second limiting circuit includes a first three-phase bridge rectifier circuit, a capacitor C2, a diode D27 and a diode D28;

[0063] The function of the first three-phase bridge rectifier circuit is to charge the capacitor C2 regardless of the polarity of the input voltage. The function of C2 is to suppress the sudden change of the spark voltage at the open circuit. The function of D27 and D28 is voltage clamping.

[0064] The first three-phase bridge rectifier circuit includes a fifth bridge arm, a sixth bridge arm, a seventh bridge arm, an eighth bridge arm, a ninth bridge arm and a tenth bridge arm, and the fifth bridge arm, the sixth bridge arm, the seventh bridge arm, the eighth bridge arm, the ninth bridge arm and the tenth bridge arm are respectively provided with a diode D21, a diode D22, a diode D23, a diode D24, a diode D25 and a diode D26;

[0065] The anode of the diode D21 and the cathode of the diode D22 are both connected to the first output terminal I of the first three-phase bridge rectifier circuit, the anode of the diode D23 and the cathode of the diode D24 are both connected to the second output terminal J of the first three-phase bridge rectifier circuit, and the anode of the diode D25 and the cathode of the diode D26 are both connected to the third output terminal K of the first three-phase bridge rectifier circuit;

[0066] The cathodes of the diode D21, the diode D23 and the diode D25 are all connected to a common point M, and the cathodes of the diode D22, the diode D24 and the diode D25 are all connected to a common point N;

[0067] The first end of the capacitor C2, the cathode of the diode D27 and the anode of the diode D28 are all connected to a common point M, and the second end of the capacitor C2, the anode of the diode D27 and the cathode of the diode D28 are all connected to a common point N;

[0068] The first output terminal I, the second output terminal J and the third output terminal K of the first three-phase bridge rectifier circuit are connected to the first end A7 of the inductor L, the cathode A5 of the diode D and the source A4 of the switch tube S respectively.

[0069] 3. The third limiting circuit includes a second three-phase bridge rectifier circuit, a capacitor C3, a diode D37 and a diode D38;

[0070] The function of the second three-phase bridge rectifier circuit is to charge the capacitor C3 regardless of the input voltage polarity. The function of C3 is to suppress the sudden change of the spark voltage at the open circuit. The function of D37 and D38 is voltage clamping.

[0071] The second three-phase bridge rectifier circuit includes an eleventh bridge arm, a twelfth bridge arm, a thirteenth bridge arm, a fourteenth bridge arm, a fifteenth bridge arm and a sixteenth bridge arm, and the eleventh bridge arm, the twelfth bridge arm, the thirteenth bridge arm, the fourteenth bridge arm, the fifteenth bridge arm and the sixteenth bridge arm are respectively provided with a diode D31, a diode D32, a diode D33, a diode D34, a diode D35 and a diode D36;

[0072] The anode of the diode D31 and the cathode of the diode D32 are both connected to the first output terminal O of the second three-phase bridge rectifier circuit, the anode of the diode D33 and the cathode of the diode D34 are both connected to the second output terminal P of the second three-phase bridge rectifier circuit, and the anode of the diode D35 and the cathode of the diode D36 are both connected to the third output terminal Q of the second three-phase bridge rectifier circuit;

[0073] The cathodes of diode D31, diode D33 and diode D35 are all connected to a common point T, and the cathodes of diode D32, diode D34 and diode D35 are all connected to a common point U;

[0074] The first end of the capacitor C3, the cathode of the diode D37 and the anode of the diode D38 are all connected to a common point T, and the second end of the capacitor C2, the anode of the diode D37 and the cathode of the diode D38 are all connected to a common point U;

[0075] The first output terminal O, the second output terminal P and the third output terminal Q of the second three-phase bridge rectifier circuit are connected to the first end A11 of the resistor R, the first end A9 of the capacitor C and the second end A8 of the inductor L respectively.

[0076] 4. The fourth limiting circuit includes a four-arm bridge rectifier circuit, a capacitor C4, a diode D49 and a diode D50;

[0077] The function of the four-arm bridge rectifier circuit is to charge the capacitor C4 regardless of the input voltage polarity. The function of C4 is to suppress the sudden change of the spark voltage at the open circuit. The function of D49 and D50 is voltage clamping.

[0078] The four-bridge-arm bridge rectifier circuit includes a seventeenth bridge arm, an eighteenth bridge arm, a nineteenth bridge arm, a twentieth bridge arm, a twenty-first bridge arm and a twenty-second bridge arm, and the seventeenth bridge arm, the eighteenth bridge arm, the nineteenth bridge arm, the twentieth bridge arm, the twenty-first bridge arm and the twenty-second bridge arm are respectively provided with a diode D41, a diode D42, a diode D43, a diode D44, a diode D45, a diode D46, a diode D47 and a diode D48;

[0079] The anode of the diode D41 and the cathode of the diode D42 are both connected to the first output terminal V of the four-arm bridge rectifier circuit, the anode of the diode D43 and the cathode of the diode D44 are both connected to the second output terminal W of the four-arm bridge rectifier circuit, the anode of the diode D45 and the cathode of the diode D46 are both connected to the third output terminal X of the four-arm bridge rectifier circuit, and the anode of the diode D47 and the cathode of the diode D48 are both connected to the fourth output terminal Y of the four-arm bridge rectifier circuit;

[0080] The cathodes of diode D41, diode D43, diode D45 and diode D47 are all connected to a common point Z, and the cathodes of diode D42, diode D44, diode D46 and diode D48 are all connected to a common point A;

[0081] The first end of the capacitor C4, the cathode of the diode D49 and the anode of the diode D50 are all connected to a common point Z, and the second end of the capacitor C4, the anode of the diode D49 and the cathode of the diode D50 are all connected to a common point A;

[0082] The first output terminal V, the second output terminal W, the third output terminal Z and the fourth output terminal Y of the four-arm bridge rectifier circuit are respectively connected to the second end A12 of the resistor R, the second end A10 of the capacitor C, the anode A6 of the diode D and the cathode A2 of the power supply E.

[0083] The function of the capacitors C1, C2, C3 and C4 is to suppress the sudden change of the spark voltage at the open circuit. The spark voltage at the open circuit can only rise from two times the diode voltage drop to three times the diode voltage drop. In this way, no dangerous open circuit spark can be formed from beginning to end, and no arc can be formed at all, because the minimum arc-building voltage is 11-17 V. In addition, all diodes in Embodiment 1 of the present invention are preferably diodes with reduced tube voltage drop. The tube voltage drop of each diode is considered to be 0.2 V. The lower the diode tube voltage drop, the more the safety performance of the rectifier-type intrinsically safe Buck circuit provided in Embodiment 1 of the present invention can be guaranteed.

[0084] During normal operation, no open circuit sparks are generated in the first circuit, the second circuit, the third circuit and the fourth circuit, and the inputs of the first limiting circuit, the second limiting circuit, the third limiting circuit and the fourth limiting circuit are all zero, which is equivalent to protecting the open circuit.

[0085] Example 2

[0086] like Figure 2 As shown, when the spark G1 is generated at the open circuit, the spark voltage is generated between A1 and A3, which will be rectified by the rectifier bridge composed of D1, D2, D3, and D4, and the sudden change of the spark voltage will be suppressed by capacitor C1, and then the voltage will be clamped by D5 and D6. The spark voltage at the open circuit can only rise from twice the diode voltage drop of 0.4V to three times the diode voltage drop of 0.6V. In this way, no dangerous open circuit spark can be formed from beginning to end, and no arc can be formed at all.

[0087] Example 3

[0088] like Figure 3 As shown, when the spark G2 is generated at the open circuit, the spark voltage is generated between A4, A5, and A7. At this time, A4 and A7 are of equal potential, so D21 and D25 are connected in parallel, and D22 and D26 are connected in parallel. The spark voltage is rectified by the rectifier bridge composed of the parallel connection of D21 and D25, the parallel connection of D22 and D26, and D23 and D24, and the sudden change of the spark voltage is suppressed by capacitor C2. After the voltage clamping of D27 and D28, the spark voltage at the open circuit can only rise from twice the diode voltage drop 0.4V to three times the diode voltage drop 0.6V. In this way, no dangerous open circuit spark can be formed from beginning to end, and no arc can be formed at all.

[0089] Example 4

[0090] like Figure 4As shown, when the spark G3 is generated at the open circuit, the spark voltage is generated between A8, A9, and A11. At this time, A9 and A11 are of equal potential, so D31 and D33 are connected in parallel, and D24 and D34 are connected in parallel. The spark voltage is rectified by the rectifier bridge composed of the parallel connection of D31 and D33, the parallel connection of D32 and D34, and D35 and D36, and the sudden change of the spark voltage is suppressed by capacitor C3. After the voltage clamping of D37 and D38, the spark voltage at the open circuit can only rise from twice the diode voltage drop 0.4V to three times the diode voltage drop 0.6V. In this way, no dangerous open circuit spark can be formed from beginning to end, and no arc can be formed at all.

[0091] Example 5

[0092] like Figure 5 As shown, when the spark G4 is generated at the open circuit, the spark voltage is generated between A2, A6, A10, and A12. At this time, A2 and A6 are of equal potential, and A10 and A12 are of equal potential, so D41 and D43 are connected in parallel, D42 and D44 are connected in parallel, D45 and D47 are connected in parallel, and D46 and D48 are connected in parallel. The spark voltage is rectified by the rectifier bridge composed of the parallel connection of D41 and D43, the parallel connection of D42 and D44, the parallel connection of D45 and D47, and the parallel connection of D46 and D48, and the sudden change of the spark voltage is suppressed by the capacitor C4. After the voltage clamping of D49 and D50, the spark voltage at the open circuit can only rise from twice the diode voltage drop 0.4V to three times the diode voltage drop 0.6V. In this way, no dangerous open circuit spark can be formed from beginning to end, and no arc can be formed at all.

[0093] In summary, the rectifier-type intrinsically safe Buck circuit provided in the embodiment of the present invention can prevent the circuit from forming dangerous open-circuit sparks from the beginning to the end, and cannot form an arc at all through rectification, capacitor suppression and diode voltage clamping of open-circuit sparks. The circuit structure is simple, and the selection of protection devices is simple.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Ordinary technicians in the relevant field can still modify or make equivalent substitutions to the specific implementation methods of the present invention with reference to the above embodiments. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention to be approved.

Claims

1. A rectifier intrinsically safe Buck circuit, characterized in that: Includes main circuit and limiting circuit; The main circuit includes a power supply E, a switch tube S, a diode D, an inductor L, a capacitor C and a resistor R, wherein the power supply E is connected to the switch tube S through a first line, the switch tube S is connected to the inductor L through a second line, the inductor L is connected to the resistor R through a third line, the resistor R is connected to the power supply E through a fourth line, the diode D is connected between the second line and the fourth line, and the capacitor C is connected between the third line and the fourth line; The limiting circuit comprises a first limiting circuit, a second limiting circuit, a third limiting circuit and a fourth limiting circuit, wherein the first limiting circuit, the second limiting circuit, the third limiting circuit and the fourth limiting circuit are respectively connected to a first line, a second line, a third line and a fourth line; The positive electrode A1 of the power source E is connected to the drain electrode A3 of the switch tube S, and A1 and A3 form a first circuit. The source A4 of the switch tube S is connected to the first end A7 of the inductor L, the cathode A5 of the diode D is connected to A4, and A4, A5 and A7 form a second circuit; The second end A8 of the inductor L is connected to the first end A11 of the resistor R, and A8 is connected to the first end A9 of the capacitor C, and A8, A9 and A11 form a third circuit. The second end A12 of the resistor R, the second end A10 of the capacitor C, and the anode A6 of the diode D are all connected to the negative electrode A2 of the power source E, and A2, A6, A10 and A12 form a fourth circuit; The first limiting circuit includes a full-bridge rectifier circuit, a capacitor C1, a diode D5 and a diode D6; The full-bridge rectifier circuit comprises a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm, wherein the first bridge arm, the second bridge arm, the third bridge arm and the fourth bridge arm are respectively provided with a diode D1, a diode D2, a diode D3 and a diode D4; The anode of the diode D1 and the cathode of the diode D2 are both connected to the first output terminal B of the first limiting circuit, and the anode of the diode D3 and the cathode of the diode D4 are both connected to the second output terminal F of the first limiting circuit; The cathodes of the diodes D1 and D3 are connected to a common point H, and the anodes of the diodes D2 and D4 are connected to a common point G; The first end of the capacitor C1, the cathode of the diode D5 and the anode of the diode D6 are all connected to a common point H, and the second end of the capacitor C1, the anode of the diode D5 and the cathode of the diode D6 are all connected to a common point G; The first output terminal B and the second output terminal F of the first limiting circuit are connected to the positive electrode A1 of the power source E and the drain electrode A3 of the switch tube S respectively; The second limiting circuit includes a first three-phase bridge rectifier circuit, a capacitor C2, a diode D27 and a diode D28; The first three-phase bridge rectifier circuit includes a fifth bridge arm, a sixth bridge arm, a seventh bridge arm, an eighth bridge arm, a ninth bridge arm and a tenth bridge arm, and the fifth bridge arm, the sixth bridge arm, the seventh bridge arm, the eighth bridge arm, the ninth bridge arm and the tenth bridge arm are respectively provided with a diode D21, a diode D22, a diode D23, a diode D24, a diode D25 and a diode D26; The anode of the diode D21 and the cathode of the diode D22 are both connected to the first output terminal I of the first three-phase bridge rectifier circuit, the anode of the diode D23 and the cathode of the diode D24 are both connected to the second output terminal J of the first three-phase bridge rectifier circuit, and the anode of the diode D25 and the cathode of the diode D26 are both connected to the third output terminal K of the first three-phase bridge rectifier circuit; The cathodes of the diodes D21, D23 and D25 are all connected to a common point M, and the cathodes of the diodes D22, D24 and D25 are all connected to a common point N; The first end of the capacitor C2, the cathode of the diode D27 and the anode of the diode D28 are all connected to a common point M, and the second end of the capacitor C2, the anode of the diode D27 and the cathode of the diode D28 are all connected to a common point N; The first output terminal I, the second output terminal J and the third output terminal K of the first three-phase bridge rectifier circuit are connected to the first end A7 of the inductor L, the cathode A5 of the diode D and the source A4 of the switch tube S respectively.

2. The rectifier intrinsically safe Buck circuit according to claim 1, characterized in that: The third limiting circuit includes a second three-phase bridge rectifier circuit, a capacitor C3, a diode D37 and a diode D38; The second three-phase bridge rectifier circuit includes an eleventh bridge arm, a twelfth bridge arm, a thirteenth bridge arm, a fourteenth bridge arm, a fifteenth bridge arm and a sixteenth bridge arm, and the eleventh bridge arm, the twelfth bridge arm, the thirteenth bridge arm, the fourteenth bridge arm, the fifteenth bridge arm and the sixteenth bridge arm are respectively provided with a diode D31, a diode D32, a diode D33, a diode D34, a diode D35 and a diode D36; The anode of the diode D31 and the cathode of the diode D32 are both connected to the first output terminal O of the second three-phase bridge rectifier circuit, the anode of the diode D33 and the cathode of the diode D34 are both connected to the second output terminal P of the second three-phase bridge rectifier circuit, and the anode of the diode D35 and the cathode of the diode D36 are both connected to the third output terminal Q of the second three-phase bridge rectifier circuit; The cathodes of the diodes D31, D33 and D35 are all connected to a common point T, and the cathodes of the diodes D32, D34 and D35 are all connected to a common point U; The first end of the capacitor C3, the cathode of the diode D37 and the anode of the diode D38 are all connected to a common point T, and the second end of the capacitor C2, the anode of the diode D37 and the cathode of the diode D38 are all connected to a common point U; The first output terminal O, the second output terminal P and the third output terminal Q of the second three-phase bridge rectifier circuit are connected to the first end A11 of the resistor R, the first end A9 of the capacitor C and the second end A8 of the inductor L respectively.

3. The rectifier intrinsically safe Buck circuit according to claim 1, characterized in that: The fourth limiting circuit includes a four-arm bridge rectifier circuit, a capacitor C4, a diode D49 and a diode D50; The four-bridge-arm bridge rectifier circuit includes a seventeenth bridge arm, an eighteenth bridge arm, a nineteenth bridge arm, a twentieth bridge arm, a twenty-first bridge arm and a twenty-second bridge arm, and the seventeenth bridge arm, the eighteenth bridge arm, the nineteenth bridge arm, the twentieth bridge arm, the twenty-first bridge arm and the twenty-second bridge arm are respectively provided with a diode D41, a diode D42, a diode D43, a diode D44, a diode D45, a diode D46, a diode D47 and a diode D48; The anode of the diode D41 and the cathode of the diode D42 are both connected to the first output terminal V of the four-arm bridge rectifier circuit, the anode of the diode D43 and the cathode of the diode D44 are both connected to the second output terminal W of the four-arm bridge rectifier circuit, the anode of the diode D45 and the cathode of the diode D46 are both connected to the third output terminal X of the four-arm bridge rectifier circuit, and the anode of the diode D47 and the cathode of the diode D48 are both connected to the fourth output terminal Y of the four-arm bridge rectifier circuit; The cathodes of the diodes D41, D43, D45 and D47 are all connected to a common point Z, and the cathodes of the diodes D42, D44, D46 and D48 are all connected to a common point A; The first end of the capacitor C4, the cathode of the diode D49 and the anode of the diode D50 are all connected to a common point Z, and the second end of the capacitor C4, the anode of the diode D49 and the cathode of the diode D50 are all connected to a common point A; The first output terminal V, the second output terminal W, the third output terminal Z and the fourth output terminal Y of the four-arm bridge rectifier circuit are respectively connected to the second end A12 of the resistor R, the second end A10 of the capacitor C, the anode A6 of the diode D and the cathode A2 of the power supply E.

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