Hybrid circuit breaker and pre-charge control method

Abstract

The invention relates to a hybrid circuit breaker and a pre-charging control method, the hybrid circuit breaker comprises an external branch circuit, a first branch circuit, a first mechanical switch module, a second branch circuit, an electronic switch and a commutation circuit, the first branch circuit is connected in series with the external branch circuit, the first mechanical switch module is arranged on the first branch circuit, the second branch circuit is connected in parallel with the first branch circuit, and the electronic switch is arranged on the second branch circuit. The electronic switch is arranged on the second branch, the commutation circuit comprises a voltage source module and a first inductor, the voltage source module is arranged on the second branch, and the first inductor is arranged on the first branch or the second branch.

Description

Technical Field

[0001] The present invention relates to a circuit breaker, and more particularly to a hybrid circuit breaker and a pre-charging control method. Background Art

[0002] Hybrid circuit breakers play an important role in medium voltage power systems. For example, the voltage of medium voltage power systems is between 1 kV and 100 kV. Hybrid circuit breakers are set between power loads and power sources, and connect or disconnect power loads and power sources according to control commands and operating conditions. The main function of hybrid circuit breakers is to protect electronic equipment from overload conditions and isolate faulty equipment from other parts of the medium voltage power system. However, conventional hybrid circuit breakers must have at least one high voltage rated mechanical switch to achieve electrical isolation, but the cost of high voltage rated mechanical switches is high. In addition, conventional hybrid circuit breakers use electronic switches in series with high voltage rated mechanical switches to perform current steering, but electronic switches have the disadvantages of high conduction losses and low operational reliability. In addition, conventional hybrid circuit breakers require additional bypass switches and resistors to achieve pre-charging operation functions, resulting in increased cost and volume of hybrid circuit breakers.

[0003] Therefore, how to develop a hybrid circuit breaker and pre-charging control method that overcomes the above-mentioned shortcomings is an urgent need at present. Summary of the invention

[0004] The purpose of this case is to provide a hybrid circuit breaker and a pre-charging control method, which have the advantages of low cost and high functional diversity.

[0005] To achieve the above-mentioned purpose, an embodiment of the present invention provides a hybrid circuit breaker, comprising an external branch, a first branch, a first mechanical switch module, a second branch, an electronic switch and a commutation circuit. The first branch is connected in series with the external branch. The first mechanical switch module is arranged in the first branch. The second branch is connected in parallel with the first branch. The electronic switch is arranged in the second branch. The commutation circuit comprises a voltage source module and a first inductor, the voltage source module is arranged in the second branch, and the first inductor is arranged in the first branch or the second branch.

[0006] To achieve the above-mentioned purpose, another embodiment of the present case is to provide a pre-charge control method, which is applied to a DC circuit system, wherein the DC circuit system includes a switching circuit, a power supply and a capacitor module. The switching circuit is connected between the power supply and the capacitor module. The pre-charge control method includes the following steps. First, a switching circuit is provided, wherein the switching circuit includes at least one electronic switch and at least one clamping circuit. Then, at least one electronic switch is controlled to be in an off state. Then, at least one electronic switch is controlled to be turned on according to a pre-charge command. Then, the charging current flowing into the switching circuit is detected. Then, when the charging current reaches the limiting current value, at least one electronic switch is controlled to be turned off, and the charging current gradually decreases according to the limitation of at least one clamping circuit. Then, at least one electronic switch is controlled to be turned on according to a pre-charge signal. Then, when the pre-charge end condition is reached, the switch circuit is controlled to be turned on.

[0007] To achieve the above-mentioned purpose, another embodiment of the present case is to provide a pre-charging control method, which is applied to a three-phase AC circuit system, wherein the three-phase AC circuit system includes a first hybrid circuit breaker, a second hybrid circuit breaker, a third hybrid circuit breaker and an AC power supply. The AC power supply provides a three-phase voltage and includes a first phase terminal, a second phase terminal and a third phase terminal. The pre-charging control method includes the following steps. First, the first phase voltage of the three-phase voltage is provided to the first hybrid circuit breaker via the first phase terminal, the second phase voltage of the three-phase voltage is provided to the second hybrid circuit breaker via the second phase terminal, and the third phase voltage of the three-phase voltage is provided to the third hybrid circuit breaker via the third phase terminal. Then, the first hybrid circuit breaker, the second hybrid circuit breaker and the third hybrid circuit breaker are controlled to be in the off state. Then, when the first phase voltage of the three-phase voltage is equal to zero, the first hybrid circuit breaker is controlled to be turned on. Then, when the first phase voltage of the three-phase voltage is equal to the second phase voltage of the three-phase voltage, the second hybrid circuit breaker is controlled to be turned on. Next, when the third phase voltage among the three-phase voltages is equal to zero, the third hybrid circuit breaker is controlled to be turned on. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A schematic diagram of a circuit structure of a power supply system including multiple hybrid circuit breakers;

[0009] Figure 2 A schematic diagram of the circuit structure of a hybrid circuit breaker according to the first embodiment of the present invention;

[0010] Figure 3 A schematic diagram of the circuit structure of a hybrid circuit breaker according to a second embodiment of the present invention;

[0011] Figure 4 A schematic diagram of the circuit structure of a hybrid circuit breaker according to the third embodiment of the present invention;

[0012] Figure 5 A schematic diagram of the circuit structure of a hybrid circuit breaker according to a fourth embodiment of the present invention;

[0013] Figure 6 A schematic diagram of the circuit structure of a hybrid circuit breaker according to a fifth embodiment of the present invention;

[0014] Figure 7 A schematic diagram of the circuit structure of the second mechanical switch module of the hybrid circuit breaker of this case;

[0015] Fig. 8A , Figure 8B and Figure 8C They are schematic diagrams of circuit structures of different embodiments of the voltage source module of the hybrid circuit breaker of the present invention;

[0016] Fig. 9 for Figure 2 A schematic diagram of current flow in a hybrid circuit breaker is shown;

[0017] Fig.10 for Figure 2 A schematic diagram of the circuit structure of a control circuit of a hybrid circuit breaker shown;

[0018] Fig.11 for Figure 2 A schematic diagram of the circuit structure of the electronic switch of the hybrid circuit breaker shown;

[0019] Fig.12 for Fig.11 The voltage timing diagram of the electronic switch shown;

[0020] Fig.13 To constitute Fig.11 A schematic structural diagram of a magnetic element of a transformer of an electronic switch shown;

[0021] Fig.14A for Fig.13 A schematic structural diagram of a layer of a multi-layer structure of a circuit board of a magnetic element shown;

[0022] Fig. 14B for Fig.13 A schematic structural diagram of another layer structure in the multi-layer structure of the circuit board of the magnetic element shown;

[0023] Fig.15 The schematic diagram of the circuit structure of the hybrid circuit breaker in this case applied to the DC circuit system;

[0024] Fig.16 for Fig.15 A method flow chart of a pre-charging control method applied to a hybrid circuit breaker shown;

[0025] Fig.17 for Fig.15A timing diagram of the current of the hybrid circuit breaker and the load voltage of the DC circuit system shown;

[0026] Fig.18 The schematic diagram of the circuit structure of the hybrid circuit breaker in this case applied to a three-phase AC circuit system;

[0027] Fig.19 a timing diagram of the voltage provided to a three-phase AC circuit system; and

[0028] Fig. 20 for Fig.18 A method flow chart of a pre-charging control method applied to a hybrid circuit breaker in FIG.

[0029] The reference numerals are described as follows:

[0030] 1: Power system

[0031] 11: Input port

[0032] 12: Output port

[0033] 13: Converter

[0034] 14: Power supply

[0035] 15: Load

[0036] 2, 2a, 2b, 2c, 2d: Hybrid circuit breakers

[0037] 21: External branch

[0038] 22: First Branch

[0039] 23: Second Branch

[0040] 31: First mechanical switch module

[0041] 32: Second mechanical switch module

[0042] 321: Switching element

[0043] 322: Conductor element

[0044] 33: Electronic switch

[0045] 331: First secondary side circuit

[0046] 331a: First diode bridge arm

[0047] D1: The first diode

[0048] D2: Second diode

[0049] 331b: Second diode bridge arm

[0050] D3: The third diode

[0051] D4: The fourth diode

[0052] T1: First transistor

[0053] 332: Second secondary circuit

[0054] 332a: The third diode bridge arm

[0055] D5: The fifth diode

[0056] D6: The sixth diode

[0057] 332b: Fourth diode bridge arm

[0058] D7: The seventh diode

[0059] D8: The eighth diode

[0060] T2: Second transistor

[0061] 333: Transformer

[0062] 333a: Primary winding

[0063] 333b: First secondary winding

[0064] 333c: Second secondary winding

[0065] 334: Trigger Generator

[0066] TC: Transformer Capacitance

[0067] DZ1: First Zener diode

[0068] DZ2: Second Zener diode

[0069] R1: First resistor

[0070] DZ3: The third Zener diode

[0071] DZ4: Fourth Zener diode

[0072] R2: Second resistor

[0073] 34: Clamping circuit

[0074] 4: Commutation circuit

[0075] 41, 41a, 41b: Voltage source module

[0076] 411: Voltage Source

[0077] 412: First switch bridge arm

[0078] S1: First switch

[0079] S2: Second switch

[0080] 413: Second switch bridge arm

[0081] S3: The third switch

[0082] S4: The fourth switch

[0083] C1: First capacitor

[0084] S5: Fifth switch

[0085] S6: Sixth switch

[0086] S7: Seventh switch

[0087] S8: The eighth switch

[0088] C2: Second capacitor

[0089] 42: First Inductor

[0090] 43: Second inductor

[0091] A: First connection point

[0092] B: Second connection point

[0093] C: Third connection point

[0094] D: Fourth connection point

[0095] E: Fifth connection point

[0096] F: Sixth connection point

[0097] i1: first current

[0098] i2: second current

[0099] i3: third current

[0100] i4: fourth current

[0101] 5: Magnetic components

[0102] 51: Shell

[0103] 511: Sidewall

[0104] 52: Circuit board

[0105] 53: Magnetic core

[0106] 54: Primary connecting wire pair

[0107] 55: Secondary connecting wire pair

[0108] 56: First layer structure

[0109] 561: Welding point

[0110] 562: Primary winding

[0111] 563: Secondary winding

[0112] 57: Second layer structure

[0113] 571: Welding point

[0114] 573: Secondary winding

[0115] 6: DC circuit system

[0116] 61: DC power supply

[0117] 62: DC inductor

[0118] 63: Capacitor module

[0119] 64: Power Converter

[0120] 7: Three-phase AC circuit system

[0121] 71: AC power supply

[0122] Va: First phase terminal

[0123] Vb: Second phase terminal

[0124] Vc: Third phase terminal

[0125] 72: AC inductance

[0126] 73: First AC diode bridge arm

[0127] Da1: The first AC diode

[0128] Da2: The second AC diode

[0129] X: First communication node

[0130] 74: Second AC diode bridge arm

[0131] Db1: The third AC diode

[0132] Db2: The fourth AC diode

[0133] Y: Second communication node

[0134] 75: The third AC diode bridge arm

[0135] Dc1: The fifth AC diode

[0136] Dc2: Sixth AC diode

[0137] Z: The third communication node

[0138] 76: Capacitor module

[0139] 77: Power Converter

[0140] 8: Control circuit

[0141] 81: Subtractor

[0142] 82: PI controller

[0143] 83: First comparator

[0144] 84: Second comparator

[0145] Iref: reference current

[0146] G1: First signal

[0147] PWM1: first PWM signal

[0148] G2: Second signal

[0149] PWM2: Second PWM signal

[0150] t1, t2, t3: time

[0151] K1-K5, J1-J5: Steps DETAILED DESCRIPTION

[0152] Some typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different aspects without departing from the scope of the present invention, and the descriptions and drawings are essentially for illustrative purposes rather than for limiting the present invention.

[0153] See also Figure 1 and Figure 2 ,in Figure 1 The schematic diagram of the circuit structure of a power supply system including multiple hybrid circuit breakers is shown in FIG. Figure 2 FIG. 1 is a schematic diagram of the circuit structure of the hybrid circuit breaker of the first embodiment of the present invention. Figure 1As shown, the power system 1 is connected between a power source 14 and a load 15. The power source 14 may be, but is not limited to, a medium voltage power system, which may be a DC circuit system or an AC circuit system. The power system 1 includes an input port 11, an output port 12, a plurality of hybrid circuit breakers 2, and a converter 13. The power system 1 is connected to the power source 14 via the input port 11, and the power system 1 is connected to the load 15 via the output port 12. The power system 1 converts the electric energy provided by the power source 14 and provides it to the load 15. Each hybrid circuit breaker 2 is connected between the input port 11 and the converter. The converter 13 is connected between the corresponding hybrid circuit breaker 2 and the output port 12.

[0154] like Figure 2 As shown, the hybrid circuit breaker 2 includes an external branch 21, a first branch 22, a second branch 23, a first mechanical switch module 31, a second mechanical switch module 32, a plurality of electronic switches 33, a plurality of clamping circuits 34, a commutation circuit 4 and a control circuit 8. The external branch 21 is connected to the power source 14 via the input port 11 of the power system 1. The first branch 22 is connected between the external branch 21 and the converter 13. The external branch 21 and the first branch 22 are connected in series between the power source 14 and the converter 13. The second branch 23 is connected in parallel with the first branch 22. The first mechanical switch module 31 is disposed in the first branch 22. The second mechanical switch module 32 is disposed in the second branch 23. A plurality of electronic switches 33 are disposed in the second branch 23 and are connected in series with the second mechanical switch module 32. The number of clamping circuits 34 is the same as the number of electronic switches 33, and each clamping circuit 34 is disposed in the second branch 23 and is connected in parallel with the corresponding electronic switch 33.

[0155] The commutation circuit 4 includes a voltage source module 41, a first inductor 42 and a second inductor 43. The voltage source module 41 is arranged in the second branch 23. The first inductor 42 is arranged in the first branch 22. The second inductor 43 is arranged in the second branch 23 and is connected in series with the voltage source module 41. In this embodiment, the second inductor 43 and the first inductor 42 are mutually coupled, and the mutual inductance between the second inductor 43 and the first inductor 42 is greater than zero. In one embodiment, the second inductor 43 and the first inductor 42 are not mutually coupled, and the mutual inductance between the second inductor 43 and the first inductor 42 is equal to zero. The control circuit 8 is connected to the commutation circuit 4 and the first branch 22, and controls the operation of the commutation circuit 4 according to the information of the first branch 22, wherein the detailed control method of the control circuit 8 will be described later.

[0156] In this embodiment, the first mechanical switch module 31 and the second mechanical switch module 32 each have an electrical isolation function. The first mechanical switch module 31 (or the second mechanical switch module 32) can be composed of a single high voltage rated mechanical switch or a plurality of low voltage rated mechanical switches connected in series. Each low voltage rated mechanical switch includes a plurality of conductor elements connected in parallel, each conductor element having a fixed parasitic capacitance value, and the conductor element can be, but is not limited to, an inductor, wherein the detailed structure of the mechanical switch will be described later.

[0157] As can be seen from the above, the hybrid circuit breaker 2 of the present case includes a second mechanical switch module 32, and the second mechanical switch module 32 is arranged in the second branch 23. Compared with the traditional hybrid circuit breaker, the first mechanical switch module 31 and the second mechanical switch module 32 of the hybrid circuit breaker 2 of the present case can respectively include a plurality of low-voltage rated mechanical switches connected in series to replace the high-voltage rated mechanical switches, and can maintain the electrical isolation function at the same time. Therefore, the cost of the first mechanical switch module 31 and the second mechanical switch module 32 of the hybrid circuit breaker 2 of the present case is relatively low. In addition, there will be no other electronic switches connected in series with the first mechanical switch module 31 on the first branch 22 of the hybrid circuit breaker 2, thereby reducing the power loss of the hybrid circuit breaker 2 and improving its operational reliability.

[0158] See also Figure 3 , which is a schematic diagram of the circuit structure of the hybrid circuit breaker of the second embodiment of this case. Figure 3 As shown, the hybrid circuit breaker 2a of this embodiment is similar to Figure 2 In the hybrid circuit breaker 2 shown, in this embodiment, the second mechanical switch module 32 of the hybrid circuit breaker 2a is arranged on the external branch 21. In addition, the second mechanical switch module 32 of this embodiment has an electrical isolation function, but the first mechanical switch module 31 does not have an electrical isolation function. The first mechanical switch module 31 can be composed of a single high-voltage rated mechanical switch or a plurality of low-voltage rated mechanical switches connected in series, each of which includes a resistor and / or a capacitor connected in parallel. The second mechanical switch module 32 can be composed of a single high-voltage rated mechanical switch or a plurality of low-voltage rated mechanical switches connected in series, each of which includes a plurality of conductor elements connected in parallel, each of which has a fixed parasitic capacitance value, wherein the detailed structure of the mechanical switch will be described later.

[0159] See also Figure 4 , which is a schematic diagram of the circuit structure of the hybrid circuit breaker of the third embodiment of this case. Figure 4 As shown, the hybrid circuit breaker 2b of this embodiment is similar to Figure 2In the hybrid circuit breaker 2 shown in this embodiment, the commutation circuit 4 of the hybrid circuit breaker 2b does not include two inductors, but only includes a single inductor, such as a first inductor 42. The first inductor 42 is disposed in the second branch 23 and connected in series to the voltage source module 41.

[0160] See also Figure 5 , which is a schematic diagram of the circuit structure of the hybrid circuit breaker of the fourth embodiment of this case. Figure 5 As shown, the hybrid circuit breaker 2c of this embodiment is similar to Figure 2 In the hybrid circuit breaker 2 shown in this embodiment, the commutation circuit 4 of the hybrid circuit breaker 2c does not include two inductors, but only includes a single inductor, such as the first inductor 42. The first inductor 42 is disposed in the first branch 22 and connected in series to the first mechanical switch module 31.

[0161] See also Figure 6 , which is a schematic diagram of the circuit structure of the hybrid circuit breaker of the fifth embodiment of the present invention. Figure 6 As shown, the hybrid circuit breaker 2d of this embodiment is similar to Figure 2 In the hybrid circuit breaker 2 shown in the present embodiment, the second mechanical switch module 32 of the hybrid circuit breaker 2d is disposed in the external branch 21. The commutation circuit 4 of the hybrid circuit breaker 2d does not include two inductors, but only includes a single inductor, such as the first inductor 42. The first inductor 42 is disposed in the first branch 22 and is connected in series to the first mechanical switch module 31.

[0162] See also Figure 7 , which is a schematic diagram of the circuit structure of the second mechanical switch module of the hybrid circuit breaker in this case. Figure 7As shown, the second mechanical switch module 32 includes a plurality of switch elements 321 and a plurality of conductor elements 322, wherein the number of conductor elements 322 is twice the number of switch elements 321. The switch element 321 is a low voltage rated mechanical switch, wherein a plurality of switch elements 321 are connected in series. Every two conductor elements 322 are connected in parallel to the corresponding switch element 321, and the two conductor elements 322 have a fixed parasitic capacitance value. In other words, the two conductor elements 322 have sufficient voltage insulation capability, and the parasitic capacitance value between the two conductor elements 322 is used for voltage balance of the switch element 321, while maintaining electrical isolation. In some embodiments, the two conductor elements 322 are composed of two metal elements with a fixed shape, size, distance and position. For example, the two conductor elements 322 can be two metal terminals welded on a PCB, or two twisted wires with a specific number of twist turns and length, or two coils in a transformer. The connection relationship between the conductor element 322 and the switch element 321 is not limited. Of course, in some embodiments, the first mechanical switch module 31 may include a switch element 321 and two conductor elements 322 , which will not be described in detail below.

[0163] See also Fig. 8A , Figure 8B and Figure 8C , which are schematic diagrams of circuit structures of different embodiments of the voltage source module of the hybrid circuit breaker of this case. Fig. 8A As shown, the voltage source module 41 of the present embodiment includes a voltage source 411, a first switch bridge arm 412 and a second switch bridge arm 413. The voltage source 411, the first switch bridge arm 412 and the second switch bridge arm 413 are connected in parallel with each other. The first switch bridge arm 412 includes a first switch S1 and a second switch S2, the first switch S1 and the second switch S2 are connected in series, and the connection between the first switch S1 and the second switch S2 constitutes a first connection point A, and the first connection point A is connected to the electronic switch 33. The second switch bridge arm 413 includes a third switch S3 and a fourth switch S4, the third switch S3 and the fourth switch S4 are connected in series, and the connection between the third switch S3 and the fourth switch S4 constitutes a second connection point B, and the second connection point B is connected to the second inductor 43. In one embodiment, as Figure 8B As shown, the voltage source module 41a of this embodiment includes multiple Fig. 8A The voltage source module 41 shown, in other words, a plurality of Fig. 8A The voltage source modules 41 are shown connected in series to form Figure 8B The voltage source module 41a is shown.

[0164] In one embodiment, if Figure 8CAs shown, the voltage source module 41b of this embodiment includes a voltage source 411, a first switch bridge arm 412 and a second switch bridge arm 413. The voltage source 411, the first switch bridge arm 412 and the second switch bridge arm 413 are connected in parallel with each other. The first switch bridge arm 412 includes a first switch S1, a second switch S2, a third switch S3, a fourth switch S4 and a first capacitor C1. The first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 are connected in series, and the connection between the second switch S2 and the third switch S3 constitutes a first connection point A, the first connection point A is connected to the electronic switch 33, and the first capacitor C1 is connected in parallel to the second switch S2 and the third switch S3 connected in series with each other. The second switch bridge arm 413 includes a fifth switch S5, a sixth switch S6, a seventh switch S7, an eighth switch S8 and a second capacitor C2. The fifth switch S5, the sixth switch S6, the seventh switch S7 and the eighth switch S8 are connected in series. The connection between the sixth switch S6 and the seventh switch S7 forms a second connection point B. The second connection point B is connected to the second inductor 43. The second capacitor C2 is connected in parallel to the sixth switch S6 and the seventh switch S7 connected in series.

[0165] See also Fig. 9 , which is Figure 2 Schematic diagram of current flow of hybrid circuit breaker shown. As shown in the figure, when the hybrid circuit breaker 2 receives the electric energy provided by the power source 14, the first current i1 flows through the external branch 21, and the second current i2 flows through the first mechanical switch module 31 and the first inductor 42 located on the first branch 22. In this case, the second mechanical switch module 32 is turned on, and the plurality of electronic switches 33 are turned off, so the second current i2 is equal to the first current i1, and the third current i3 flowing through the second branch 23 is zero.

[0166] When the load 15 stops receiving the electric energy provided by the power source 14, the plurality of electronic switches 33 are turned on, and the commutation circuit 4 starts to operate. Fig. 8A The commutation circuit 4 shown is applied to the hybrid circuit breaker 2 for explanation. When the commutation circuit 4 starts to operate, the switches in the commutation circuit 4 are controlled to be turned on or off, thereby generating a fourth current i4 flowing through the first branch 22 and the second branch 23, and the fourth current i4 is controlled to be equal to the first current i1 according to the switches in the commutation circuit 4, so as to control the second current i2 to be zero, wherein the operation mode of the switches in the commutation circuit 4 will be described later. Therefore, the second current i2 is zero, and the third current i3 is equal to the first current i1. When the second current i2 is zero, the first mechanical switch module 31 is turned off, the commutation circuit 4 stops operating, and then the multiple electronic switches 33 are turned off. The third current i3 flows through the clamping circuit 34, and the voltage on the electronic switch 33 is clamped by the corresponding clamping circuit 34, and the first current i1 drops to zero. Then the second mechanical switch module 32 is turned off.

[0167] See also Fig.10 And cooperate Figure 2 ,in Fig.10 for Figure 2 Schematic diagram of the circuit structure of the control circuit of the hybrid circuit breaker shown. As shown in the figure, the control circuit 8 is connected to the first branch 22 and the commutation circuit 4, and the control circuit 8 includes a subtractor 81, a PI controller 82, a first comparator 83 and a second comparator 84. The subtractor 81 receives the second current i2 and the reference current Iref, and subtracts the second current i2 from the reference current Iref. The PI controller 82 is used to process the output value of the subtractor 81. The first comparator 83 receives the output value and the first signal G1 provided by the PI controller 82 to output the first PWM signal PWM1 to the first switch bridge arm 412 of the commutation circuit 4. The second comparator 84 receives the output value and the second signal G2 of the PI controller 82 to output the second PWM signal PWM2 to the second switch bridge arm 413 of the commutation circuit 4.

[0168] See also Fig.11 and Fig.12 ,in Fig.11 for Figure 2 The circuit structure diagram of the electronic switch of the hybrid circuit breaker shown in FIG. Fig.12 for Fig.11 The voltage timing diagram of the electronic switch is shown in FIG. Fig.11 As shown, at least two electronic switches 33 are controlled by a driving circuit. The first electronic switch 33 includes a first secondary side circuit 331 and a first transistor T1. The first secondary side circuit 331 includes a first diode bridge arm 331a and a second diode bridge arm 331b. The first diode bridge arm 331a includes a first diode D1 and a second diode D2. The first diode D1 and the second diode D2 are connected in series, and the connection between the anode of the first diode D1 and the cathode of the second diode D2 constitutes a third connection point C. The second diode bridge arm 331b includes a third diode D3 and a fourth diode D4. The third diode D3 and the fourth diode D4 are connected in series, and the connection between the anode of the third diode D3 and the cathode of the fourth diode D4 constitutes a fourth connection point D. The first transistor T1 is connected in parallel to the first diode bridge arm 331a and the second diode bridge arm 331b.

[0169] The second electronic switch 33 includes a second secondary side circuit 332 and a second transistor T2. The second secondary side circuit 332 includes a third diode bridge arm 332a and a fourth diode bridge arm 332b. The third diode bridge arm 332a includes a fifth diode D5 and a sixth diode D6. The fifth diode D5 and the sixth diode D6 are connected in series, and the connection between the anode of the fifth diode D5 and the cathode of the sixth diode D6 constitutes a fifth connection point E. The fourth diode bridge arm 332b includes a seventh diode D7 and an eighth diode D8. The seventh diode D7 and the eighth diode D8 are connected in series, and the connection between the anode of the seventh diode D7 and the cathode of the eighth diode D8 constitutes a sixth connection point F. The second transistor T2 is connected in parallel to the third diode bridge arm 332a and the fourth diode bridge arm 332b.

[0170] The driving circuit includes a transformer 333, a trigger generator 334, a primary side circuit, a first secondary side circuit and a second secondary side circuit. The primary side circuit includes a transformer capacitor TC. The first secondary side circuit includes a first Zener diode DZ1, a second Zener diode DZ2 and a first resistor R1, the first resistor R1 is connected between the first transistor T1 and the first Zener diode DZ1, and the second Zener diode DZ2 is connected to the first transistor T1. The second secondary side circuit includes a third Zener diode DZ3, a fourth Zener diode DZ4 and a second resistor R2, the second resistor R2 is connected between the second transistor T2 and the third Zener diode DZ3, and the fourth Zener diode DZ4 is connected to the second transistor T2.

[0171] The transformer 333 includes a primary winding 333a, a first secondary winding 333b, and a second secondary winding 333c. The primary winding 333a is connected to the trigger generator 334, and the trigger generator 334 generates a trigger signal to the primary winding 333a. The first secondary winding 333b is coupled to the primary winding 333a and connected between the first Zener diode DZ1 and the second Zener diode DZ2. The second secondary winding 333c is coupled to the primary winding 333a and connected between the third Zener diode DZ3 and the fourth Zener diode DZ4. In this embodiment, the transformer capacitor TC is connected between the trigger generator 334 and the primary winding 333a.

[0172] like Fig.12 As shown, Vi in the figure represents the voltage on the primary winding 333a, that is, the trigger voltage generated by the trigger generator 334, Vo in the figure represents the voltage on the first secondary winding 333b or the voltage on the second secondary winding 333c, and Vg in the figure represents the gate voltage of the first transistor T1 or the gate voltage of the second transistor T2. When the trigger generator 334 generates a positive voltage Vin+, the first secondary winding 333b or the second secondary winding 333c generates a positive voltage Vout+.

[0173] See also Fig.13 , which constitutes Fig.11 The structure diagram of the magnetic element of the transformer of the electronic switch shown in the figure. As shown in the figure, the magnetic element 5 constitutes Fig.11 The transformer 333 of the electronic switch 33 shown in FIG. 1 is a magnetic element 5. The magnetic element 5 comprises a housing 51, a circuit board 52, a magnetic core 53, a primary connecting wire pair 54, a plurality of secondary connecting wire pairs 55 and an insulating material. The housing 51 comprises a plurality of side walls 511, and the primary connecting wire pair 54, a plurality of secondary connecting wire pairs 55 and the magnetic core 53 are arranged in the housing 51. The circuit board 52 is located in the housing 51. The magnetic core 53 passes through the circuit board 52 and is located in the housing 51. At least part of the primary connecting wire pair 54 is located in the housing 51 and is adjacent to a corresponding side wall 511 of the plurality of side walls 511. Each secondary connecting wire pair 55 is at least partly located in the housing 51 and is adjacent to another side wall 511 of the plurality of side walls 511, and the other part of each secondary connecting wire pair 55 is exposed from the housing 51. The insulating material is filled in the housing 51. The circuit board 52, the magnetic core 53, at least part of the primary connecting wire pair 54 and each secondary connecting wire pair 55 are embedded in the insulating material. The other part of each primary connection wire pair 54 and the other part of each secondary connection wire pair 55 are connected to the circuit board 52. The space inside the housing 51 is filled with insulating material. Fig.13 The insulating material is omitted. In one embodiment, the insulating material may be made of silicone, epoxy resin, mineral oil or other types of insulating glue or liquid. The magnetic element 5 constituting the transformer 333 of the electronic switch 33 has the advantages of easy manufacturing, low cost, circuit parameter and performance consistency, reduced clearance and creepage distance requirements, and small size.

[0174] See also Fig.14A And cooperate Fig.13 ,in Fig.14A for Fig.13 The schematic diagram of the structure of a layer in the multi-layer structure of the circuit board of the magnetic element shown in the figure. As shown in the figure, the circuit board 52 is composed of a printed circuit board with a multi-layer structure. For the convenience of explanation, Fig.14A Only the first layer structure of the multilayer structure is shown. The first layer structure 56 includes a plurality of welding points 561, a primary winding 562 and a secondary winding 563. Each welding point 561 is connected to a corresponding primary connecting wire pair 54 or a corresponding secondary connecting wire pair 55, the primary winding 562 is connected to the primary connecting wire pair 54 via the corresponding welding point 561, and the secondary winding 563 is connected to the secondary connecting wire pair 55 via the corresponding welding point 561.

[0175] See also Fig. 14B And cooperate Fig.13 ,in Fig. 14B for Fig.13 The schematic diagram of the structure of another layer of the multi-layer structure of the circuit board of the magnetic element shown. For the convenience of explanation, Fig. 14B Only the second layer structure of the multi-layer structure is shown. The second layer structure 57 includes a plurality of welding points 571 and a secondary winding 573. Each welding point 571 is connected to a corresponding primary connecting wire pair 54 or a secondary connecting wire pair 55, and the secondary winding 573 can be a single wire or a twisted pair, and is connected to the secondary connecting wire pair 55 via the corresponding welding point 571. In one embodiment, the circuit board 52 includes a first layer structure 56 and a plurality of second layer structures 57. In other words, the plurality of secondary windings 563, 573 are respectively arranged on different layer structures of the circuit board 52, and at least one primary winding 562 is arranged on at least one layer structure of the circuit board 52.

[0176] See also Figures 15 to 17 ,in Fig.15 The schematic diagram of the circuit structure of the hybrid circuit breaker in this case applied to the DC circuit system is shown in FIG. Fig.16 for Fig.15 The method flow chart of the pre-charging control method applied to the hybrid circuit breaker shown in FIG. Fig.17 for Fig.15 The timing diagram of the current of the hybrid circuit breaker and the load voltage of the DC circuit system is shown in FIG. Fig.15 As shown, the hybrid circuit breaker 2 is applied to a DC circuit system 6. The DC circuit system 6 includes a DC power supply 61, a DC inductor 62, a capacitor module 63 and a power converter 64. The DC inductor 62 and the hybrid circuit breaker 2 are connected between the positive terminal of the DC power supply 61 and the first terminal of the power converter 64. The capacitor module 63 is located in the power converter 64. In one embodiment, the capacitor module 63 includes one or more capacitors, wherein the multiple capacitors can be connected in parallel, in series, in parallel and in series, or in any other connection relationship. The power converter 64 is used to convert the voltage of the capacitor module 63 to an external electrical element (not shown).

[0177] like Fig.16As shown, first, step K1 is executed to provide a switching circuit, wherein the switching circuit includes at least one electronic switch 33 and at least one clamping circuit 34. Then, step K2 is executed to control at least one electronic switch 33 to be in an off state. Then, step K3 is executed to control at least one electronic switch 33 to be turned on according to the pre-charge command. Then, step K4 is executed to detect the charging current (i.e., the first current i1) flowing into the switching circuit. Then, step K5 is executed to control at least one electronic switch 33 to be turned off when the charging current reaches the limiting current value, and the charging current gradually decreases according to the limitation of at least one clamping circuit 34. Then, step K6 is executed to control at least one electronic switch 33 to be turned on according to the pre-charge signal. Then, step K7 is executed to control the switching circuit to be turned on when the pre-charge end condition is reached.

[0178] In one embodiment, the pre-charge command is a command instructing the DC circuit system to pre-charge, the pre-charge signal is determined based on the time it takes for the charging current to drop to zero, and the pre-charge end condition is the difference between the capacitor module voltage and the power supply voltage, wherein the pre-charge end condition is less than a preset difference.

[0179] like Fig.17 As shown, when the hybrid circuit breaker 2 outputs current to the capacitor module 63, the capacitor module 63 is charged. In other words, when the current on the hybrid circuit breaker 2 increases, the voltage of the capacitor module 63 increases accordingly. When the current on the hybrid circuit breaker 2 reaches a threshold, for example Fig.17 When the current limit value shown is reached, the electronic switch 33 is controlled to be turned off, and then the current of the hybrid circuit breaker 2 decreases. At the same time, the capacitor module 63 stops charging. In other words, when the current on the hybrid circuit breaker 2 drops to zero, the voltage on the capacitor module 63 stops increasing.

[0180] The hybrid circuit breaker 2 will repeat the above-mentioned pre-charging method until the voltage on the capacitor module 63 reaches the pre-charging end condition, wherein the charging current is determined by the tolerance of the electronic switch.

[0181] See also Figures 18 to 20 ,in Fig.18 The schematic diagram of the circuit structure of the hybrid circuit breaker in this case applied to the three-phase AC circuit system is shown in FIG. Fig.19 The timing diagram of the voltage provided by the three-phase AC circuit system, Fig. 20 for Fig.18 A method flow chart of the pre-charging control method applied to the hybrid circuit breaker in FIG. Fig.18As shown, three hybrid circuit breakers 2 are applied to a three-phase AC circuit system 7. For example, the first hybrid circuit breaker 2, the second hybrid circuit breaker 2 and the third hybrid circuit breaker 2 are applied to the three-phase AC circuit system 7. The three-phase AC circuit system 7 includes an AC power source 71, three AC inductors 72, a first AC diode bridge arm 73, a second AC diode bridge arm 74, a third AC diode bridge arm 75, a capacitor module 76 and a power converter 77. The AC power source 71 provides a three-phase voltage and includes a first phase terminal Va, a second phase terminal Vb and a third phase terminal Vc. The AC power source 71 provides a first phase voltage of the three-phase voltage via the first phase terminal Va, the AC power source 71 provides a second phase voltage of the three-phase voltage via the second phase terminal Vb, and the AC power source 71 provides a third phase voltage of the three-phase voltage via the third phase terminal Vc, wherein the three voltage phases of the first phase terminal Va, the second phase terminal Vb and the third phase terminal Vc are respectively shown in Fig.19 middle.

[0182] The first AC diode bridge arm 73 includes a first AC diode Da1 and a second AC diode Da2 connected in series, and the connection point between the first AC diode Da1 and the second AC diode Da2 constitutes a first AC node X. The first AC inductor 72 and the first hybrid circuit breaker 2 are connected in series and are located between the first phase terminal Va of the AC power source 71 and the first AC node X. The second AC diode bridge arm 74 includes a third AC diode Db1 and a fourth AC diode Db2 connected in series, and the connection point between the third AC diode Db1 and the fourth AC diode Db2 constitutes a second AC node Y. The second AC inductor 72 and the second hybrid circuit breaker 2 are connected in series and are located between the second phase terminal Vb of the AC power source 71 and the second AC node Y. The third AC diode bridge arm 75 includes a fifth AC diode Dc1 and a sixth AC diode Dc2 connected in series, and the connection point between the fifth AC diode Dc1 and the sixth AC diode Dc2 constitutes a third AC node Z. The third AC inductor 72 and the third hybrid circuit breaker 2 are connected in series and are located between the third phase terminal Vc of the AC power source 71 and the third AC node Z. The first AC diode bridge arm 73 , the second AC diode bridge arm 74 , the third AC diode bridge arm 75 and the power converter 77 are connected in parallel.

[0183] like Fig. 20As shown, first, step J1 is executed, the first phase voltage of the three-phase voltage is provided to the first hybrid circuit breaker 2 via the first phase terminal Va, the second phase voltage of the three-phase voltage is provided to the second hybrid circuit breaker 2 via the second phase terminal Vb, and the third phase voltage of the three-phase voltage is provided to the third hybrid circuit breaker 2 via the third phase terminal Vc. Then, step J2 is executed to control the first hybrid circuit breaker 2, the second hybrid circuit breaker 2 and the third hybrid circuit breaker 2 to be in the off state. Then, step J3 is executed, when the first phase voltage of the three-phase voltage is equal to zero, the first hybrid circuit breaker 2 is controlled to be turned on. Then, step J4 is executed, when the first phase voltage of the three-phase voltage is equal to the second phase voltage of the three-phase voltage, the second hybrid circuit breaker 2 is controlled to be turned on. Then, step J5 is executed, when the third phase voltage of the three-phase voltage is equal to zero, the third hybrid circuit breaker 2 is controlled to be turned on. In this embodiment, each hybrid circuit breaker 2 is kept in the on state and is not closed.

[0184] In this embodiment, there is a first delay time between the conduction time of the first hybrid circuit breaker 2 and the conduction time of the second hybrid circuit breaker 2, wherein the first delay time corresponds to Fig.19 There is a second delay time between the conduction time of the second hybrid circuit breaker 2 and the conduction time of the third hybrid circuit breaker 2, wherein the second delay time corresponds to Fig.19 The time interval between the moments t2 and t3. In this embodiment, the conduction time of the first hybrid circuit breaker 2, the conduction time of the second hybrid circuit breaker 2, and the conduction time of the third hybrid circuit breaker 2 all exist in the same line voltage cycle of the three-phase voltage. In some embodiments, the conduction time of the first hybrid circuit breaker 2, the conduction time of the second hybrid circuit breaker 2, and the conduction time of the third hybrid circuit breaker 2 do not necessarily exist in the same line voltage cycle of the three-phase voltage, but exist in different line voltage cycles of the three-phase voltage according to actual needs.

[0185] In some embodiments, the pre-charging control method is not only applied to power systems, but also applicable to three-phase AC circuit systems with any type of circuit breaker systems, such as mechanical circuit breaker systems and solid-state circuit breaker systems.

[0186] In summary, the hybrid circuit breaker of the present case includes a second mechanical switch module, and the second mechanical switch module is located in the second branch. Compared with the traditional hybrid circuit breaker, the first mechanical switch module and the second mechanical switch module of the hybrid circuit breaker of the present case can respectively use a plurality of low-voltage rated mechanical switches connected in series to replace the high-voltage rated mechanical switches, while maintaining the electrical isolation function. Therefore, the cost of the first mechanical switch module and the second mechanical switch module of the hybrid circuit breaker of the present case is relatively low. In addition, the second mechanical switch module of the hybrid circuit breaker of the present case includes a switch element and two conductor elements, and there is a fixed parasitic capacitance value between the two conductor elements. In other words, the two conductor elements have sufficient voltage insulation capability, and the parasitic capacitance value between the two conductor elements is used for voltage balance of the switch element, and at the same time maintains electrical isolation, so that the second mechanical switch module of the hybrid circuit breaker of the present case is more stable. In addition, the hybrid circuit breaker of the present invention includes a commutation circuit to control the current of the hybrid circuit breaker, and on the first branch, the first mechanical switch module is not connected in series with the electronic switch, thereby reducing the power loss of the hybrid circuit breaker and improving its operational reliability. In addition, the transformer of the electronic switch of the hybrid circuit breaker is composed of a magnetic element, and the magnetic element includes an insulating material filled in the shell. Therefore, the magnetic device of the transformer forming the electronic switch has the advantages of easy manufacturing, low cost, consistency of circuit parameters and performance, reduced clearance and creepage distance requirements, and small size. In addition, the hybrid circuit breaker of the present invention can be applied to a DC circuit system or an AC circuit system to pre-charge the load of the DC circuit system or the AC circuit system, thereby improving the functional diversity of the hybrid circuit breaker of the present invention.

Claims

1. A hybrid circuit breaker, comprising: an external branch; a first branch connected in series with the external branch; A first mechanical switch module, disposed in the first branch; a second branch connected in parallel with the first branch; an electronic switch, disposed in the second branch; and A commutation circuit includes a voltage source module and a first inductor. The voltage source module is arranged in the second branch, and the first inductor is arranged in the first branch or the second branch. 2 . The hybrid circuit breaker as claimed in claim 1 , wherein the hybrid circuit breaker comprises a second mechanical switch module, which is disposed in the external branch or the second branch.

3. A hybrid circuit breaker as described in claim 2, wherein the second mechanical switch module is arranged in the second branch, the first mechanical switch module and the second mechanical switch module respectively include a plurality of low-voltage rated switch elements and a plurality of conductor elements, the plurality of low-voltage rated switch elements are connected in series, and every two conductor elements of the plurality of conductor elements are connected in parallel to the corresponding low-voltage rated switch elements, and the two conductor elements have a fixed parasitic capacitance value.

4. A hybrid circuit breaker as described in claim 2, wherein the second mechanical switch module is arranged in the external branch, and the second mechanical switch module comprises a plurality of low-voltage rated switch elements and a plurality of conductor elements, the plurality of low-voltage rated switch elements are connected in series, and every two conductor elements of the plurality of conductor elements are connected in parallel to the corresponding low-voltage rated switch elements, and the two conductor elements have a fixed parasitic capacitance value.

5. The hybrid circuit breaker as claimed in claim 1, wherein the first inductor is arranged in the first branch, the commutation circuit comprises a second inductor, the second inductor is arranged in the second branch, and the second inductor is coupled to the first inductor.

6. The hybrid circuit breaker as claimed in claim 1, wherein the hybrid circuit breaker comprises at least one clamping circuit, the number of the at least one clamping circuit is equal to the number of the electronic switches, and the at least one clamping circuit is disposed in the second branch and connected in parallel to the electronic switch.

7. A hybrid circuit breaker as described in claim 1, wherein the hybrid circuit breaker includes a driving circuit, the driving circuit includes a transformer, a primary side circuit and at least one secondary side circuit, the at least one secondary side circuit includes a first Zener diode, a second Zener diode and a first resistor, the first resistor is connected between the electronic switch and the first Zener diode, the transformer includes a primary winding and at least one secondary winding, the primary winding is connected to a trigger generator via the primary side circuit, the at least one secondary winding is coupled to the primary winding and connected between the first Zener diode and the second Zener diode.

8. The hybrid circuit breaker as claimed in claim 7, wherein the transformer comprises a shell, the interior of the shell is used to accommodate a printed circuit board with a multi-layer structure, a plurality of secondary windings are arranged on the multi-layer structure of the printed circuit board, the primary winding is arranged on at least one layer of the printed circuit board, wherein a magnetic core, a primary connecting wire pair and a plurality of secondary connecting wire pairs are arranged on a circuit board, and an insulating material is filled in the shell.

9. A pre-charge control method, applied to a DC circuit system, the DC circuit system comprising a switch circuit, a power supply and a capacitor module, the switch circuit being connected between the power supply and the capacitor module, wherein the pre-charge control method comprises: (a) providing a switching circuit, the switching circuit comprising at least one electronic switch and at least one clamping circuit; (b) controlling the at least one electronic switch to be in an off state; (c) controlling the at least one electronic switch to be turned on according to a pre-charge command; (d) detecting a charging current flowing into the switch circuit; (e) when the charging current reaches a limiting current value, controlling the at least one electronic switch to be turned off, and the charging current gradually decreases according to the limitation of the at least one clamping circuit; (f) controlling the at least one electronic switch to be turned on according to a pre-charge signal; and (g) When a pre-charging end condition is reached, the switch circuit is controlled to be turned on.

10. The pre-charge control method as claimed in claim 9, wherein the pre-charge command is a command instructing the DC circuit system to perform pre-charge, and the pre-charge signal is determined according to the time when the charging current drops to zero.

11. The pre-charging control method as claimed in claim 9, wherein the pre-charging end condition is a difference between the voltage of the capacitor module and the voltage of the power supply, wherein the pre-charging end condition is less than a preset difference.

12. The pre-charge control method as claimed in claim 9, wherein there is a first delay time between two conductions of the DC circuit system.

13. The pre-charge control method as claimed in claim 9, wherein the charging current is determined by a tolerance of the electronic switch.

14. A pre-charging control method, applied to a three-phase AC circuit system, the three-phase AC circuit system comprising a first hybrid circuit breaker, a second hybrid circuit breaker, a third hybrid circuit breaker and an AC power source, the AC power source providing a three-phase voltage and comprising a first phase terminal, a second phase terminal and a third phase terminal, wherein the pre-charging control method comprises: (a) a first phase voltage among the three-phase voltage is provided to the first hybrid circuit breaker via the first phase terminal, a second phase voltage among the three-phase voltage is provided to the second hybrid circuit breaker via the second phase terminal, and a third phase voltage among the three-phase voltage is provided to the third hybrid circuit breaker via the third phase terminal; (b) controlling the first hybrid circuit breaker, the second hybrid circuit breaker and the third hybrid circuit breaker to be in an off state; (c) when the first phase voltage among the three-phase voltage is equal to zero, controlling the first hybrid circuit breaker to be turned on; (d) when the first phase voltage among the three-phase voltage is equal to the second phase voltage among the three-phase voltage, controlling the second hybrid circuit breaker to be turned on; and (e) When the third phase voltage among the three-phase voltages is equal to zero, the third hybrid circuit breaker is controlled to be turned on.

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