CN108599117B - A bidirectional DC solid state circuit breaker - Google Patents

Abstract

The invention relates to a bidirectional DC solid-state circuit breaker, which includes a three-coil transformer module, a first diode, a second diode, a first thyristor, a second thyristor and a capacitor; the circuit topology adopts a three-coil transformer to realize bidirectional energy transfer Flow; the circuit topology realizes the common ground of the power supply and the load, which is convenient for practical promotion; the semiconductor switching components used in the circuit topology are less, which reduces the complexity of the circuit and reduces the cost.

Description

A bidirectional DC solid state circuit breaker

technical field

The invention belongs to the technical field of direct current circuit breakers, and in particular relates to a circuit structure of a novel bidirectional direct current solid state circuit breaker.

Background technique

The solid-state circuit breaker is a new type of electric power automation equipment that can quickly cut off the fault current when a circuit fault occurs. It has the advantages of fast response, short switching time, and high reliability. It is one of the key equipment to ensure the stability, safety and reliability of the DC transmission and distribution system and the DC grid system.

At present, DC circuit breakers are mainly divided into three categories, namely, pure mechanical DC circuit breakers that use traditional mechanical switches to break, all solid-state circuit breakers that use power electronic devices (SCR, IGBT) to break, and hybrids that combine the two forms. circuit breaker. However, mechanical circuit breakers have disadvantages such as long turn-off time and easy arc generation, while ordinary solid-state circuit breakers have disadvantages such as complex circuits, low reliability, difficult control and high cost.

Moreover, most current circuit breakers are unidirectional structures, which can no longer meet the needs of existing DC microgrids. For example, a Z-source DC circuit breaker provided by a Chinese patent (patent number: 201510858644.9) can use a semi-controlled device in the circuit to realize fault isolation of the circuit, but cannot realize the bidirectional protection function of the circuit. Some bidirectional circuit breakers also have problems such as complex structure, different load and power supply, and large current feedback. For example, a bidirectional DC circuit breaker provided by Chinese patent (patent number: 201610630952.0) can realize bidirectional flow of energy, but There are problems of complex structure, too many power electronic devices, and difficult control. These severely restrict the development of DC microgrids.

Contents of the invention

technical problem to be solved

In order to overcome the disadvantages of the existing one-way circuit breaker that can only realize energy flow in one direction and the circuit structure load of the two-way circuit breaker, the load and the power supply are not in the same ground, and feedback large current, etc., the present invention provides a new type of bidirectional DC solid-state circuit breaker The circuit topology of the device.

Technical solutions

A bidirectional DC solid-state circuit breaker, comprising a three-coil transformer module, a first diode, a second diode, a first thyristor, a second thyristor and a capacitor; the first lead-out terminal of the three-coil transformer module and the first thyristor Cathode connection; the second lead-out terminal of the three-coil transformer module is connected to the cathode of the second thyristor; the third lead-out terminal of the three-coil transformer module is connected to the anode of the capacitor; the three coils of the three-coil transformer module intersect at the connection point; the first The anode of the diode and the anode of the second diode are connected at a point and connected with the connection point of the three coils of the transformer; the cathode of the second diode is connected with the anode of the first thyristor, and its connection point is used as the first lead-out terminal; The cathode of a diode is connected to the anode of the second thyristor, and its connection point is used as the second lead-out terminal; the cathode of the capacitor is used as the third lead-out terminal; the first lead-out terminal is connected to the positive pole of the power supply, and the second lead-out terminal is connected to the short-circuit point, DC The third lead-out terminal of the circuit breaker is connected to the DC bus.

The three-coil transformer module is composed of three coils of the transformer and respective energy absorbing circuits of the three coils, the absorbing circuit is composed of a diode and a resistor, and the diode and the resistor of the absorbing circuit are connected in series and then connected in parallel at both ends of the transformer coil; the three coils The cathode of the diode of the absorbing circuit at the first lead-out end of the transformer module is connected to the cathode of the first thyristor, and the anode of the diode at the absorbing circuit at the first lead-out end is connected in series with the first resistor and connected to the connection point of the three coils; the absorbing circuit at the second lead-out end The cathode of the diode is connected to the cathode of the second thyristor, and the anode of the diode of the absorbing circuit at the second lead end is connected in series with the second resistor and connected to the connection point of the three coils; the negative electrode of the absorbing circuit at the third lead end is connected to the anode of the capacitor, The anode of the diode of the absorption circuit of the third terminal is connected in series with the third resistor and connected to the connection points of the three coils, the cathode of the diode of the absorption circuit of the first terminal is connected to the cathode of the first thyristor, and the diode of the absorption circuit of the second terminal is The connection point of the cathode of the negative pole of the second thyristor and the cathode of the second thyristor, the negative pole of the diode of the absorption circuit of the third lead-out end and the anode connection point of the capacitor are the terminals with the same name of the three-coil transformer module.

Beneficial effect

A bidirectional DC solid-state circuit breaker proposed by the present invention has the beneficial effects of: 1) the circuit topology uses a three-coil transformer to realize bidirectional flow of energy; 2) the circuit topology realizes the common ground of the power supply and the load, which is convenient for practical promotion ; 3) Fewer semiconductor switching components are used in the circuit topology, which reduces the complexity and cost of the circuit.

Description of drawings

FIG. 1 is a schematic diagram of the circuit topology of the present invention.

Figure 2 is an example waveform diagram.

In the figure, 1—transformer module, 2—first diode, 3—second diode, 4—first thyristor, 5—second thyristor, 6—capacitor, 7—transformer three-coil intersection, 8—first The intersection of the anode of the first diode and the anode of the second diode, 9—the first lead-out terminal of the circuit breaker, 10—the second lead-out terminal of the circuit breaker, 11—the third lead-out terminal of the circuit breaker, 12, 13, 14—transformer coils, 15, 16, 17—the diodes of the absorbing loops of the three coils of the transformer, 18, 19, 20—the resistance of the absorbing loops of the transformer, 21, 22, 23—the end of the same name of the transformer, 24—DC power supply, 25—short circuit point.

Detailed ways

Now in conjunction with embodiment, accompanying drawing, the present invention will be further described:

The technical scheme that the present invention takes is, as shown in Figure 1:

The topology of the bidirectional DC circuit breaker is composed of a three-coil transformer module 1 , a first diode 2 , a second diode 3 , a first thyristor 4 , a second thyristor 5 and a capacitor 6 . The first lead-out terminal of the transformer module 1 is connected to the cathode of the first thyristor 4; the second lead-out terminal of the transformer module is connected to the cathode of the second thyristor 5; the third lead-out terminal of the transformer module 1 is connected to the anode of the capacitor 6; the transformer module The three coils of 1 intersect at connection point 7; the positive pole of the first diode 2 and the positive pole of the second diode are connected at point 8 and connected with the transformer three-coil connection point 7; the negative pole of the second diode 3 is connected with The anode of the first thyristor 4 is connected, and its connection point is used as the first lead-out terminal 9 of the DC circuit breaker topology; the negative pole of the first diode 2 is connected to the anode of the second thyristor 5, and its connection point is used as the first lead-out terminal 9 of the DC circuit breaker topology; The second lead-out terminal 10 of the DC circuit breaker topology; the capacitor cathode serves as the third lead-out terminal 11 of the DC circuit breaker topology.

The transformer module is composed of three coils 12, 13, 14 of the transformer and energy absorbing loops of the three coils, and the absorbing loops are composed of diodes and resistors. The diode and resistor of the snubber circuit are connected in series and then in parallel at both ends of the transformer coil. The negative pole of the diode 15 of the absorption circuit at the first terminal of the transformer module is connected to the cathode of the first thyristor 4 at point 21, and the positive pole of the diode 15 is connected with the intersection point 7 of the three coils after the series resistance 18; the absorption circuit at the second terminal of the transformer The negative pole of the diode 16 is connected to the cathode of the second thyristor 5 at point 22, and the positive pole of the diode 16 is connected to the intersection point 7 of the three coils after the resistor 19 is connected in series; Intersecting at point 23, the anode of diode 17 is connected in series with resistor 20 to the intersection point 7 of the three coils. Intersections 21, 22, and 23 are terminals with the same name of the three-coil transformer. The first lead-out terminal 9 of the DC circuit breaker is connected to the positive pole of the power supply 24, the second lead-out terminal 10 of the DC circuit breaker is connected to the short-circuit point 25, and the third lead-out terminal 11 of the DC circuit breaker is connected to the DC bus.

The bidirectional DC solid state circuit breaker can realize bidirectional energy flow. The first thyristor 4, the coil 12 of the first port of the transformer module, the coil 14 of the third port of the transformer module, the capacitor 6 and the first diode 2 constitute the forward flow channel of the energy of the circuit topology; the second thyristor 5. The coil 13 of the second port of the transformer module, the coil 14 of the third port of the transformer module, the capacitor 6 and the second diode 3 constitute the energy backward flow channel of the circuit topology.

When there is no DC short-circuit fault, the current flows through the main branch (the first thyristor 4, the coil 12 of the first port of the transformer module, the first diode 2). When a DC short-circuit fault occurs, the capacitor discharges, and the coil 14 of the third port of the transformer module flows through an instantaneous current. At the same time, a reverse current is induced at the first port of the transformer module so that the current flowing through the first thyristor 4 is Zero, and then make the thyristor withstand back pressure shutdown, to achieve isolation and removal of the fault.

The simulation is carried out for an example, taking the forward flow of energy as an example. Set the power supply voltage Us=28V, the inductance 12 at the first lead-out terminal of the transformer module is 1000 μH, the inductance 13 at the second lead-out terminal of the transformer module is 1000 μH, the inductance 14 at the third lead-out terminal of the transformer module is 125 μH, and the capacitor 6 is 500μF, the load resistance is 100Ω, and the fault resistance is 0.5Ω. The waveform diagram obtained by simulation is shown in Fig. 2 .

It can be seen from Figure 2 that the current of capacitor 6 is 0 when the circuit is working normally. When a short-circuit fault occurs at the load end, the current flowing through the transformer coil cannot change suddenly due to the inductance of the coil, and the magnitude of the fault current is completely determined by capacitor 6 and load current supply. The discharge of the capacitor 6 generates an instantaneous large current. At the same time, due to the mutual inductance of the transformer, a reverse current is generated to turn off the first thyristor 4 , the current of the thyristor becomes zero, and the first thyristor 4 is turned off under the back pressure. After the discharge is completed, the voltage of the capacitor 6 becomes 0. The present invention only takes about 1 ms from the occurrence of the fault to the complete isolation of the fault, and the action is rapid.

Claims (2)

1. a kind of bidirectional, dc solid circuit breaker, it is characterised in that including three-winding transformer module (1), first diode (2), Second diode (3), the first thyristor (4), the second thyristor (5) and capacitor (6)；The of three-winding transformer module (1) One leading-out terminal is connect with the cathode of the first thyristor (4)；Second leading-out terminal of three-winding transformer module (1) and the second crystalline substance The cathode of brake tube (5) connects；The third leading-out terminal of three-winding transformer module (1) is connect with the anode of capacitor (6)；Three-winding Three coils of transformer module (1) intersect at tie point (7)；The anode of first diode (2) and the second diode (3) are just Pole is connected to point (8) and connect with transformer three-winding tie point (7)；The cathode and the first thyristor (4) of second diode (3) Anode connection, first leading-out terminal (9) of the tie point as dc circuit breaker；The cathode and second of first diode (2) The anode of thyristor (5) connects, second leading-out terminal (10) of the tie point as dc circuit breaker；Capacitor (6) cathode conduct The third leading-out terminal (11) of dc circuit breaker；First leading-out terminal (9) is connect with power supply (24) anode, the second leading-out terminal (10) it is connect with short dot (25), the third leading-out terminal (11) of dc circuit breaker is connect with DC bus.

2. a kind of bidirectional, dc solid circuit breaker according to claim 1, it is characterised in that the three-winding transformer Module (1) is made of three coils and the respective energy absorption circuit of three coils of transformer, and absorption circuit is by diode It is constituted with resistance, diode and the resistance series connection of absorption circuit and then the both ends for being parallel to transformer coil；Three-winding transformer The cathode of the diode (15) of module the first exit absorption circuit is connect with the cathode of the first thyristor (4), the first exit Diode (15) anode series connection first resistor (18) of absorption circuit is connected with the tie point of three coils (7) afterwards；Second draws The cathode of the cathode and the second thyristor (5) of holding the diode (16) of absorption circuit connects, and the two of the second exit absorption circuit Pole pipe (16) anode series connection second resistance (19) is connected with the tie point of three coils (7) afterwards；Third exit absorption circuit The cathode of diode (17) is connected with the anode of capacitor (6), the diode (17) of third exit absorption circuit anode series connection the Three resistance (20) are connected with the tie point of three coils (7) afterwards, the cathode of the diode (15) of the first exit absorption circuit with The cathode connection of first thyristor (4), the second exit absorption circuit diode (16) cathode and the second thyristor (5) Cathode connection, third exit absorption circuit diode (17) cathode and capacitor (6) anode tie point be three lines The Same Name of Ends of coil transformer module (1).