CN215733441U - Hybrid direct current breaker - Google Patents
Hybrid direct current breaker Download PDFInfo
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- CN215733441U CN215733441U CN202120268285.2U CN202120268285U CN215733441U CN 215733441 U CN215733441 U CN 215733441U CN 202120268285 U CN202120268285 U CN 202120268285U CN 215733441 U CN215733441 U CN 215733441U
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Abstract
The utility model provides a hybrid direct current circuit breaker, comprising: a mechanical switch connected to the first current branch; and a semiconductor switch and a forced resonance injection circuit connected to the second current branch, the forced resonance injection circuit comprising first and second terminals, the first terminal of the forced resonance injection circuit being connected to one end of the semiconductor switch, and the second terminal and the other end of the semiconductor switch being connected to both ends of the mechanical switch; wherein, when the mechanical switch is in the process of being switched off, the semiconductor switch is controlled to be switched on, and simultaneously the forced resonance injection circuit is controlled to inject an injection current which is opposite to the current direction in the mechanical switch and gradually increases into the mechanical switch, so that the current in the mechanical switch is gradually reduced to zero in a preset commutation time and the current is commutated from the first current branch to the second current branch. The hybrid direct current circuit breaker can safely and reliably break the fault and the load current in any direction.
Description
Technical Field
The utility model relates to the field of circuit breakers, in particular to a hybrid direct current circuit breaker.
Background
Due to the lack of voltage zero-crossing points, the direct current power supply system has the problem that fault current is difficult to cut off. In order to cut off the fault current rapidly and make the mechanical switch arc-free to break, a hybrid dc circuit breaker is proposed, which comprises a mechanical switch, a semiconductor switch connected in parallel with the mechanical switch, and a surge arrester (or surge arrester, surge protector or surge protector).
The basic principle of the hybrid direct current circuit breaker is as follows: when a fault current (e.g., a short circuit current) occurs in the dc circuit, the mechanical switch is triggered to open. In the process of disconnecting the mechanical switch, in order to avoid electric arcs generated in the process of disconnecting the mechanical switch as much as possible, the semiconductor switch is controlled to be switched on first, so that current is converted into the semiconductor switch, then the mechanical switch is disconnected, and after the mechanical switch is disconnected, the semiconductor switch is then disconnected, so that the rapid breaking process of short-circuit current is completed, wherein the surge arrester is used for absorbing residual electric energy in a direct-current power supply system.
However, the existing hybrid dc circuit breaker cannot ensure that the mechanical switch is fully arc-free opened, and cannot determine when to turn on the semiconductor switch so that the mechanical switch safely and reliably turns off the fault current.
SUMMERY OF THE UTILITY MODEL
To solve the above technical problems in the prior art, the present invention provides a hybrid dc circuit breaker, including:
a mechanical switch connected to the first current branch; and
the semiconductor switch and the forced resonance injection circuit are connected to the second current branch, the forced resonance injection circuit comprises a first terminal and a second terminal, the first terminal of the forced resonance injection circuit is connected to one end of the semiconductor switch, and the second terminal of the forced resonance injection circuit and the other end of the semiconductor switch are connected to two ends of the mechanical switch;
wherein, when the mechanical switch is in the process of being switched off, the semiconductor switch is controlled to be switched on, and simultaneously the forced resonance injection circuit is controlled to inject an injection current which is opposite to the current direction in the mechanical switch and gradually increases into the mechanical switch, so that the current in the mechanical switch is gradually reduced to zero in a preset reversing time and the current is reversed from the first current branch to the second current branch.
Preferably, the forced resonant injection circuit is controlled to stop outputting the injected current when the current in the mechanical switch falls to zero within a predetermined commutation time.
Preferably, the semiconductor switch is controlled to be turned off when a contact pitch of the mechanical switch reaches a predetermined threshold value.
Preferably, the forced resonance injection circuit includes: the power supply of the direct current power supply is from direct current voltage on the first current branch or an external power supply so as to charge a direct current bus capacitor; a direct current bus connected to the direct current bus capacitance and configured to provide current to the forced resonance injection circuit; an inverter supplied with switching pulses during current injection to generate square wave periodic voltage pulses of alternating polarity; the resonant circuit comprises an inductor and a capacitor which are connected in series, one end of the resonant circuit is connected to the output end of the inverter, and the other end of the resonant circuit is used for outputting alternating current with gradually increased amplitude; the input end of the rectifying circuit is connected to the other end of the resonant circuit, and the output end of the rectifying circuit is used for outputting pulsating direct current with gradually increased amplitude; the input end of the output module is electrically connected to the output end of the rectifying circuit, the output end of the output module is used as a first terminal and a second terminal of the forced resonance injection circuit, and the output module is used for filtering and amplifying the pulsating direct current and outputting the injection current; wherein the inverter, the resonant circuit, an equivalent resistance, an equivalent inductance and an equivalent capacitance of a circuit connected between the other end of the resonant circuit and the output of the inverter form an underdamped resonant circuit, the frequency of the square wave periodic voltage pulses being dependent on the resonant frequency of the underdamped resonant circuit.
Preferably, the semiconductor switch is a bidirectional controllable semiconductor switch; the hybrid dc circuit breaker further includes a polarity module connected between the rectifying circuit and the output module, the polarity module including a full bridge circuit controlled to change polarities of an input current and an output current of the polarity module.
Preferably, the inverter is a single-level, bi-level or multi-level full-bridge inverter or a half-bridge inverter.
Preferably, the output module is configured to generate a current break between its input and the first current branch.
Preferably, the output module is an autotransformer including a first winding and a second winding, a first terminal of the first winding is electrically connected to a first output terminal of the rectifying circuit, a second terminal of the first winding is electrically connected to a first terminal of the second winding and serves as a first output terminal of the forced resonance injection circuit, and a second terminal of the second winding is electrically connected to a second output terminal of the rectifying circuit and serves as a second output terminal of the forced resonance injection circuit.
Preferably, said transformer or said autotransformer is coreless.
Preferably, the polarity module includes: the first and second switching transistors are connected to form a first bridge arm, and a first node formed by connecting the first and second switching transistors is used as the first polarity terminal; a third switching transistor and a fourth switching transistor which are connected to form a second bridge arm, wherein a second node formed by connecting the third switching transistor and the fourth switching transistor is used as the second polarity terminal; wherein a first electrode of the first switching transistor and a first electrode of the third switching transistor are connected to a positive output terminal of the rectifier circuit, and a second electrode of the second switching transistor and a second electrode of the fourth switching transistor are connected to a negative output terminal of the rectifier circuit.
Preferably, the hybrid dc circuit breaker further comprises a surge arrester connected in parallel with the semiconductor switch.
In the normal power supply process of the direct current power supply system, the power consumption of the forced resonance injection circuit is zero. When fault current occurs in a direct current power supply system, the forced resonance injection circuit controllably injects injection current which is opposite in current direction and gradually increased into the mechanical switch, so that the time of current commutation can be controlled, and the two ends of the mechanical switch have smaller recovery voltage, so that the mechanical switch can safely and reliably cut off the fault current.
Drawings
Embodiments of the utility model are further described below with reference to the accompanying drawings, in which:
fig. 1 is a block diagram of a hybrid dc circuit breaker according to a preferred embodiment of the present invention.
Fig. 2 is a diagram of current waveforms in the hybrid dc circuit breaker shown in fig. 1.
Fig. 3 shows a detailed block diagram of a forced resonance injection circuit in the hybrid dc circuit breaker shown in fig. 1.
Fig. 4 is a waveform diagram of a resonance current output from the resonance circuit in the forced resonance injection circuit shown in fig. 3.
Fig. 5 is a waveform diagram of a rectified current output from a rectifier circuit in the forced resonance injection circuit shown in fig. 3.
Fig. 6 is a waveform diagram of an injection current output from an output block in the forced resonance injection circuit shown in fig. 3.
Fig. 7 is a detailed circuit diagram of a hybrid dc circuit breaker according to a first embodiment of the present invention.
Fig. 8 is a detailed circuit diagram of a polarity module in a hybrid dc circuit breaker according to a second embodiment of the present invention.
Fig. 9 is a detailed circuit diagram of an output module in a hybrid dc circuit breaker according to a third embodiment of the present invention.
Fig. 10 is a detailed circuit diagram of a semiconductor switch in a hybrid dc circuit breaker according to a fourth embodiment of the present invention.
Fig. 11 is a detailed circuit diagram of an inverter in a hybrid dc breaker according to a fifth embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail by embodiments with reference to the accompanying drawings.
Fig. 1 is a block diagram of a hybrid dc circuit breaker according to a preferred embodiment of the present invention. As shown in fig. 1, the hybrid dc circuit breaker 1 comprises a mechanical switch 11 connected to a first current branch, and a semiconductor switch 13 and a forced resonant injection circuit 14 connected to a second current branch. The forced resonance injection circuit 14 includes a terminal 1461 and a terminal 1462, the terminal 1461 of the forced resonance injection circuit 14 is connected to one end of the semiconductor switch 13, and the other end of the semiconductor switch 13 and the terminal 1462 of the forced resonance injection circuit 14 are connected to both ends of the mechanical switch 11. The hybrid dc breaker 1 further comprises a surge arrester 12 connected in parallel with the semiconductor switch 13.
For the sake of convenience of the following description, the currents I in the mechanical switches 11 are respectively marked with arrows in fig. 1SWCurrent I in surge arrester 12ACurrent I in the semiconductor switch 13BAn injection current I output by the forced resonance injection circuit 14CAnd the current I in the hybrid DC breaker 1CBIn the direction of (a).
The forced resonance injection circuit 14 is controlled to output a gradually increasing injection current ICWherein the injection current ICInto the mechanical switch 11 in the direction corresponding to the current I in the mechanical switch 11SWAnd for causing a current I in the mechanical switch 11SWGradually decreasing to zero during a predetermined commutation time.
Fig. 2 is a diagram of current waveforms in the hybrid dc circuit breaker shown in fig. 1. As shown in fig. 2, before time t1, the dc power supply system is in a normal power supply state, there is no fault current in the circuit, the mechanical switch 11 is in a conducting state, and the semiconductor switch 13 is in a blocking state, and the dc power supply system supplies power to a load (not shown in fig. 1) normally through the conducting mechanical switch 11, at which time the current I in the surge arrester 12ACurrent I in the semiconductor switch 13BAnd the injection current I output by the forced resonance injection circuit 14CAll are zero, the current I in the mechanical switch 11SWEqual to the current I in the hybrid dc breaker 1CB. Since the current in the resonant injection circuit 14 is forced to zero, the power loss of the resonant injection circuit 14 is forced to zero during normal powering.
At time t1, when the load is short-circuited, the current I in the mechanical switch 11SWSharply rising and current I in the hybrid dc breaker 1CBAnd rises sharply.
At time t2, the current I in the mechanical switch 11SWWhen the tripping current is raised, the control means or trip circuit (not shown in fig. 1) starts to control the mechanical switch 11 to open.
From time t2 to time t3, the contact of the mechanical switch 11 is in the separation process, and the current I in the mechanical switch 11SWGradually increasing and current I in the hybrid DC breaker 1CBGradually increasing.
At time t3, the semiconductor switch 13 is controlled to be turned on, and the forced resonance injection circuit 14 is controlled to output the injection current I from time t3CInjection current ICIs flowing from the terminal 1461 to the terminal 1462 and along the current I in the mechanical switch 11SWInto the mechanical switch 11 in the opposite direction.
The injection current I outputted from the forced resonance injection circuit 14 from time t3 to time t4CGradually increases and the current I in the semiconductor switch 13 increasesBGradually increase due to the injection current ICAnd the current I in the mechanical switch 11SWIn opposite directions, so that the current I in the mechanical switch 11 isSWAnd gradually decreases. In the process, the current I in the mechanical switch 11SWGradually commutates into the semiconductor switch 13 and the current I in the semiconductor switch 13BAnd the current I in the hybrid DC breaker 1CBAnd the rise is continued.
At time t4, the current I in the mechanical switch 11SWZero, the current commutation process is completed, and the injection current I output by the forced resonance injection circuit 14 is controlledCEqual to zero, stopping the injection of current into the mechanical switch 11.
Time t4 to time tt5, the short-circuit current flows only through the semiconductor switch 13 in the conducting state, and the current I in the semiconductor switch 13BContinues to increase and the current I in the hybrid dc breaker 1CBGradually increasing. During this process, the movable contact of the mechanical switch 11 continues to open at a speed of several meters per second, and the distance between the movable contact and the stationary contact reaches the predetermined contact distance at time t 5. Injection current I output by forced resonance injection circuit 14CSo that the current I in the mechanical switch 11SWHaving been commutated into the semiconductor switch 13, the mechanical switch 11 will not be subjected to a high current interruption in the process, i.e. need not be switched off at a high current. In particular, the mechanical switch 11 will achieve zero current turn-off and arc-less turn-off.
At time t5, the control device (not shown in fig. 1) controls the semiconductor switch 13 to be in the off or disconnected state, the current I in the semiconductor switch 13BDrops to zero, at which time the current I in the hybrid dc breaker 1CBA maximum value is reached.
From time t5 to time t6, since no potential zero-crossing exists in the dc power supply system, the residual electric energy in the dc power supply system is discharged through the surge arrester 12 and the terminals 1461, 1462 of the forced resonance injection circuit 14, and the surge arrester 12 starts consuming the electric energy in the dc power supply system, so that the current I in the surge arrester 12 flowsAGradually decreases to zero while the current I in the hybrid dc breaker 1CBGradually decreasing to zero. Finally, at time t6, a fault clearance is achieved.
In the hybrid dc circuit breaker 1 of the present invention, the two terminals 1461, 1462 of the forced resonance injection circuit 14 and the semiconductor switch 13 are connected in series to the second current branch and are not connected to the first current branch in which the mechanical switch 11 is located, so that the dc power supply system supplies power to the load only through the mechanical switch 11 during normal power supply or transmission of dc power, and the power consumption of the forced resonance injection circuit 14 is zero.
In addition, the forced resonance injection circuit 14 of the utility model can controllably inject the current I into the mechanical switch 11 during the opening process of the mechanical switch 11SWIn the opposite directionAnd a gradually increasing injection current ICCapable of controlling the current I in the mechanical switch 11SWCommutation from time t3 to time t4 to the semiconductor switch 13, i.e. the time of commutation of the current can be controlled.
The forced resonance injection circuit 14 can control the current I in the semiconductor switch 13 at the end time t4 of the current commutationBA smaller current change rate allows the mechanical switch 11 to have a larger quick turn-off capability and smaller turn-off loss. At the end of the commutation of the current (i.e. at time t4), the recovery voltage across the mechanical switch 11 depends on the resistance of the semiconductor switch 13 and the current I in the semiconductor switch 13BThe recovery voltage across the mechanical switch 11 can be made small, for example, several volts to several tens of volts. At the end of the current commutation, the mechanical switch 11 has a smaller rate of change of the current, while the mechanical switch 11 has a smaller recovery voltage across it, so that the mechanical switch 11 can be safely and reliably switched off.
The time period from the time t4 to the time t5 is a turn-off delay time of the hybrid dc circuit breaker 1, and is used for enabling the distance between the moving contact and the stationary contact of the mechanical switch 11 to reach a predetermined contact distance within the turn-off delay time, where the predetermined contact distance and the turn-off delay time depend on the recovery voltage of the mechanical switch 11 and the opening speed of the moving contact.
When the hybrid dc breaker 1 is used in a bidirectional dc supply system, for example, the current direction in the hybrid dc breaker 1 and the above-mentioned current ICBWhen the direction of (2) is opposite, the forced resonance injection circuit 14 is controlled so that its terminal 1461 outputs an injection current which gradually increases.
Fig. 3 shows a detailed block diagram of a forced resonance injection circuit in the hybrid dc circuit breaker shown in fig. 1. As shown in fig. 3, the forced resonance injection circuit 24 includes a dc power source 241, a dc bus capacitor C1 connected between dc buses, an inverter 242, a resonant circuit 243, a rectifying circuit 244, a polarity module 245, and an output module 246, wherein an input terminal of the inverter 242 is connected to the dc power source 241, an output terminal thereof is connected to an input terminal of the rectifying circuit 244 through the resonant circuit 243, an output terminal of the rectifying circuit 244 is connected to an input terminal of the polarity module 245, an output terminal of the polarity module 245 is connected to an input terminal of the output module 246, and one terminal 2461 of the output module 246 is connected to one end of the semiconductor switch 23, and the other terminal 2462 is connected to one end of the mechanical switch 21.
The dc power source 241 is supplied from a dc voltage on the first current branch or an external power source to charge the dc bus capacitance C1; the dc bus capacitor C1 supplies current to the forced resonant injection circuit through the dc bus.
Wherein the equivalent resistance, equivalent capacitance, and equivalent inductance of the inverter 242, resonant circuit 243, rectification circuit 244, polarity module 245, and output module 246 form an underdamped resonant circuit.
A control device (not shown in fig. 3) provides a high-frequency (e.g., 10 to 100KHz) pulse width modulation signal, i.e., a switching pulse, to the inverter 242, so that the inverter 242 inverts the dc current on the dc bus capacitor C1 into an ac current, i.e., a square wave periodic voltage pulse with alternating polarity, wherein the frequency of the square wave periodic voltage pulse depends on the resonant frequency of the underdamped resonant circuit, so that the resonant circuit 243 outputs a resonant current IRES。
The output module 246 is further configured to generate a current break between its input and the first current branch.
Fig. 4 is a waveform diagram of a resonance current output from the resonance circuit in the forced resonance injection circuit shown in fig. 3. As shown in fig. 4, the resonant current IRESIs an alternating current with gradually increasing amplitude, and the resonant frequency is determined by the natural frequency of the inductance, the capacitance and the equivalent resistance (e.g., the body resistance of the inductance and the capacitance) of the equivalent load circuit. At the start of oscillation, the inverter 242 outputs a voltage to the resonant circuit 243, whereby the resonant circuit 243 starts generating an oscillating current. When the resonant current IRESAt each zero crossing, the inverter 242 is controlled to switch the polarity of the output voltage, and the electric energy on the dc bus capacitor C1 is output to the resonant circuit 243 through the inverter 242, so that the electric energy is provided in each switching period, and the resonant current I output by the resonant circuit 243 is enabledRESGradually increases in amplitude.
Rectifying circuit 244For outputting a resonant current I from the resonant circuit 243RESRectified into pulsating direct current.
Fig. 5 is a waveform diagram of a rectified current output from a rectifier circuit in the forced resonance injection circuit shown in fig. 3. As shown in fig. 5, the rectified current IRThe current direction is unchanged and the amplitude is periodically increased for pulsating direct current.
The polarity module 245 includes a positive input terminal, a negative input terminal, a polarity terminal 2451 and a polarity terminal 2452, the positive and negative input terminals of the polarity module 245 being connected to the positive and negative output terminals of the rectification circuit 244, respectively. The polarity module 245 controllably makes its polarity terminals 2451, 2452 positive and negative output terminals, or makes its polarity terminals 2451, 2452 negative and positive output terminals. The polarity module 245 thereby outputs pulsating direct current that is in phase or in phase opposition to the pulsating direct current output by the rectifier circuit 244.
The output module 246 is used for filtering or reducing the ac component in the pulsating dc power outputted from the polarity module 245, so as to output a gradually increasing and smooth dc power.
Fig. 6 is a waveform diagram of an injection current output from an output block in the forced resonance injection circuit shown in fig. 3. As shown in FIG. 6, the injection current I output by the output module 246CIs a smooth direct current whose amplitude gradually increases with time. Injection current ICIs output from terminal 2462 of the output module 246 and flows into the mechanical switch 21 such that the current in the mechanical switch 21 gradually decreases to zero during the current commutation time.
By providing a high frequency (e.g., 10-100 KHz) pulse width modulated signal to the inverter 242, the output module 246 is enabled to output a gradually increasing and smooth direct current over several cycles of the switching frequency (e.g., tens to hundreds of microseconds), thereby enabling a fault current in the mechanical switch 21 to be rapidly commutated into the semiconductor switch 23.
In other embodiments of the present invention, when the hybrid dc breaker 2 is used in a unidirectional dc power supply system, the hybrid dc breaker 2 may not have the polarity module 245, and the semiconductor switch 23 may be a unidirectional controllable semiconductor switch.
Fig. 7 is a detailed circuit diagram of a hybrid dc circuit breaker according to a first embodiment of the present invention. As shown in fig. 7, the semiconductor switch 33 is a bidirectional controllable switch including an insulated gate bipolar transistor T31 having an antiparallel diode and an insulated gate bipolar transistor T32 having an antiparallel diode, wherein an emitter of the insulated gate bipolar transistor T31 is connected to an emitter of the insulated gate bipolar transistor T32. And the unidirectional conduction of the direct current is realized by controlling the conduction of the insulated gate bipolar transistor T31 or T32.
The inverter 342 is a full bridge inverter composed of four field effect transistors.
The resonant circuit 343 comprises an inductor L3 and a capacitor C3 connected in series, and the inductor L3 and the capacitor C3 are selected to meet the requirement
An underdamped resonant circuit is formed. Where R ', L ', and C ' are equivalent resistance values, equivalent inductance values, and equivalent capacitance values of the inverter 342, the resonant circuit 343, the rectifier circuit 344, the polarity module 345, and the output module 346, respectively. For example, an equivalent resistance value, an equivalent inductance value, and an equivalent capacitance value of 3.5 ohms, 150 muh, and 82nF, respectively, an underdamped resonant circuit is formed.
The switching frequency of the inverter 342 depends on the resonant frequency of the underdamped resonant circuit, e.g., 150 muH inductor L3 and 82nF capacitor C3 are selected, and the switching frequency of the inverter 342 is
I.e. about 45 KHz.
When the two diagonally opposite igbt's in the inverter 342 are controlled to be turned on, the dc power supply 341 outputs power through the two diagonally opposite igbt's, and thus the resonant circuit 343 outputs a current of the first polarity. When the other diagonally opposite two igbts in the inverter 342 are controlled to be turned on, the dc power source 341 outputs power through the turned-on two igbts, so that the resonant circuit 343 outputs a current of the second polarity with an increased magnitude. The igbt in the inverter 342 is controlled to be alternately turned on in the above two manners, so that the resonant circuit 343 outputs alternating current power of gradually increasing amplitude for a plurality of switching cycles of the pulse width modulation signal.
The rectifying circuit 344 is a full-wave rectifying circuit including 4 diodes.
The polarity module 345 comprises a full bridge circuit that is controlled to change the polarity of the input current and the output current of the polarity module. Specifically, the polarity module 345 includes four insulated gate bipolar transistors T33, T34, T35, and T36 having inverse parallel diodes, and diodes D33, D34, D35, and D36 connected in series with the insulated gate bipolar transistors T33, T34, T35, and T36, respectively. A node N1 formed by connecting the series-connected igbt T33 and diode D33 with the series-connected igbt T34 and diode D34 serves as the polarity terminal 3451 of the polarity block 345, and a node N2 formed by connecting the series-connected igbt T35 and diode D35 with the series-connected igbt T36 and diode D36 serves as the polarity terminal 3452 of the polarity block 345. Wherein the polarity terminals 3451, 3452 serve as the positive output terminal and the negative output terminal, respectively, of the polarity module 345 when the diagonally opposite igbt T33 and T36 are controlled to be conductive. When the diagonally opposite igbt T34 and T35 are controlled to be on, the polarity terminals 3451, 3452 serve as the negative output terminal and the positive output terminal of the polarity block 345, respectively.
The output module 346 is an autotransformer that is coreless to prevent magnetic saturation. The autotransformer includes winding L31 and winding L32, the dotted end of winding L31 is connected to node N1, the dotted end of winding L32 is connected to the non-dotted end of winding L31 and serves as terminal 3461 of output module 346, and the non-dotted end of winding L32 is connected to node N2 and serves as terminal 3462 of output module 346.
When the polarity terminal 3452 of the polarity module 345 outputs the current I31 and flows into the non-dotted terminal of the winding L32, the current I31 flows from the non-dotted terminal of the winding L31 to the dotted terminal thereof, and the dotted terminal of the winding L32 to the dotted terminal thereofThe non-dotted terminal has a current I32, and the terminal 3462 outputs an injection current ICIn which a current I is injectedCEqual to the sum of current I31 and current I32. Injection current ICInto the mechanical switch 31, thereby causing a current I in the mechanical switch 31SWGradually decreases to zero over a predetermined current commutation time.
Fig. 8 is a detailed circuit diagram of a polarity module in a hybrid dc circuit breaker according to a second embodiment of the present invention. As shown in fig. 8, the polarity module 445 includes four igbt transistors T43, T44, T45 and T46 without antiparallel diodes, where the igbt transistors T43 and T44 are connected to form one leg and the igbt transistors T45 and T46 are connected to form the other leg. Specifically, the collectors of the igbts T43 and T45 are connected to each other and are connected to the positive output terminal of the rectifier circuit, the emitters of the igbts T44 and T46 are connected to each other and are connected to the negative output terminal of the rectifier circuit, a node N41 formed by connecting the emitter of the igbts T43 to the collector of the igbts T44 serves as one polarity terminal 4451 of the polarity module 445, and a node N42 formed by connecting the emitter of the igbts T45 to the collector of the igbts T46 serves as the other polarity terminal 4452 of the polarity module 445.
When the diagonally opposite igbt T43 and T46 are controlled to be on and the igbt T44 and T45 are controlled to be off, the polarity terminals 4451 and 4452 serve as a positive output terminal and a negative output terminal, respectively, in which current flows out from the polarity terminal 4451 and flows in from the polarity terminal 4452. When the other diagonally opposite igbt T44 and T45 are controlled to be on and the igbt T43 and T46 are controlled to be off, the polarity terminals 4451 and 4452 function as a negative output terminal and a positive output terminal, respectively, in which current flows out from the polarity terminal 4452 and into the polarity terminal 4451.
Fig. 9 is a detailed circuit diagram of an output module in a hybrid dc circuit breaker according to a third embodiment of the present invention. As shown in fig. 9, the output moldThe block 446 is a coreless transformer comprising a primary winding L41 and a secondary winding L42, wherein the dotted and non-dotted terminals of the primary winding L41 are for connection to the positive and negative output terminals of the rectifying circuit 244, respectively, or to the two polarity terminals 2451, 2452 of the polarity module 245, and the dotted and non-dotted terminals of the secondary winding L42 are for connection to the semiconductor and mechanical switches, respectively, as output terminals 4461, 4462, respectively. When current flows from the non-dotted terminal of the primary winding L41 to the dotted terminal, current in the secondary winding L42 flows from the output terminal 4461 to the output terminal 4462. The transformer 446 without magnetic core has the function of current isolation and can reduce the high-frequency resonance current IRESPower consumption caused during transmission.
Fig. 10 is a detailed circuit diagram of a semiconductor switch in a hybrid dc circuit breaker according to a fourth embodiment of the present invention. As shown in fig. 10, the semiconductor switch 43 includes a bridge circuit formed by connecting four diodes D41, D42, D43, and D44, and an insulated gate bipolar transistor T41 whose collector is connected to the cathodes of the diodes D41 and D43 and whose emitter is connected to the anodes of the diodes D42 and D44. When igbt T41 is controlled to be conductive, one of the conductive paths is current flowing from terminal 431 through diode D41, conductive igbt T41, diode D44 to terminal 432; the other conductive path is current flowing from terminal 432 through diode D43, conducting igbt T41, diode D42 to terminal 431.
Fig. 11 is a detailed circuit diagram of an inverter in a hybrid dc breaker according to a fifth embodiment of the present invention. As shown in fig. 11, the inverter 442 is a half-bridge inverter, which includes igbt T47, T48, and capacitors C41 and C42, wherein positive and negative input terminals of the half-bridge inverter 442 are electrically connected to positive and negative electrodes of the dc power source 241, respectively, for inverting the dc power output from the dc power source 241 into ac power. The half-bridge inverter 442 has only two switching transistors, and thus can save device cost.
In other embodiments of the utility model, the inverter may also be a single-level, bi-level or multi-level full bridge (H-bridge) inverter.
In another embodiment of the present invention, a switch transistor such as a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) may be used to replace the semiconductor switch 33 and/or the igbt in the polarity module 345 in the above embodiments.
In another embodiment of the utility model, the hybrid dc circuit breaker may comprise a plurality of semiconductor switches 33 in series.
In another embodiment of the present invention, the rectifying circuit 244 may adopt a half-wave rectifying circuit or the like to rectify the alternating current into a pulsating direct current.
Although the present invention has been described by way of preferred embodiments, the present invention is not limited to the embodiments described herein, and various changes and modifications may be made without departing from the scope of the present invention.
Claims (12)
1. A hybrid dc circuit breaker, comprising:
a mechanical switch connected to the first current branch; and
the semiconductor switch and the forced resonance injection circuit are connected to the second current branch, the forced resonance injection circuit comprises a first terminal and a second terminal, the first terminal of the forced resonance injection circuit is connected to one end of the semiconductor switch, and the second terminal of the forced resonance injection circuit and the other end of the semiconductor switch are connected to two ends of the mechanical switch;
wherein, when the mechanical switch is in the process of being switched off, the semiconductor switch is controlled to be switched on, and simultaneously the forced resonance injection circuit is controlled to inject an injection current which is opposite to the current direction in the mechanical switch and gradually increases into the mechanical switch, so that the current in the mechanical switch is gradually reduced to zero in a preset reversing time and the current is reversed from the first current branch to the second current branch.
2. A hybrid dc circuit breaker according to claim 1, characterized in that the forced resonant injection circuit is controlled to stop outputting the injected current when the current in the mechanical switch falls to zero within a predetermined commutation time.
3. A hybrid dc circuit breaker according to claim 2, characterized in that the semiconductor switch is controlled to be switched off when the contact pitch of the mechanical switch reaches a predetermined threshold value.
4. A hybrid dc circuit breaker according to any of claims 1 to 3, characterized in that the forced resonant injection circuit comprises:
the power supply of the direct current power supply is from direct current voltage on the first current branch or an external power supply so as to charge a direct current bus capacitor;
a direct current bus connected to the direct current bus capacitance and configured to provide current to the forced resonance injection circuit;
an inverter supplied with switching pulses during current injection to generate square wave periodic voltage pulses of alternating polarity;
the resonant circuit comprises an inductor and a capacitor which are connected in series, one end of the resonant circuit is connected to the output end of the inverter, and the other end of the resonant circuit is used for outputting alternating current with gradually increased amplitude;
the input end of the rectifying circuit is connected to the other end of the resonant circuit, and the output end of the rectifying circuit is used for outputting pulsating direct current with gradually increased amplitude; and
an output module, an input end of which is electrically connected to an output end of the rectifying circuit, and an output end of which is used as a first terminal and a second terminal of the forced resonance injection circuit, wherein the output module is used for filtering and amplifying the pulsating direct current and outputting the injection current;
wherein the inverter, the resonant circuit, an equivalent resistance, an equivalent inductance and an equivalent capacitance of a circuit connected between the other end of the resonant circuit and the output of the inverter form an underdamped resonant circuit, the frequency of the square wave periodic voltage pulses being dependent on the resonant frequency of the underdamped resonant circuit.
5. Hybrid direct current circuit breaker according to claim 4,
the semiconductor switch is a bidirectional controllable semiconductor switch;
the hybrid direct current breaker further comprises a polarity module connected between the rectification circuit and the output module, the polarity module comprising a full bridge circuit controlled to change the polarity of the input current and the output current of the polarity module; and
the full-bridge circuit has a first polarity terminal and a second polarity terminal as its output terminal, and the output terminal of the full-bridge circuit is electrically connected to the input terminal of the output module.
6. Hybrid dc circuit breaker according to claim 4, characterized in that the inverter is a single-level, bi-level or multilevel full bridge inverter or half bridge inverter.
7. A hybrid DC circuit breaker according to claim 4, characterized in that the output module is configured as a transformer to produce a current break between its input and the first current branch.
8. The hybrid dc circuit breaker of claim 4, wherein the output module is an autotransformer including a first winding and a second winding, a first terminal of the first winding being electrically connected to a first output terminal of the rectifying circuit, a second terminal of the first winding being electrically connected to a first terminal of the second winding and functioning as a first output terminal of the forced resonance injection circuit, a second terminal of the second winding being electrically connected to a second output terminal of the rectifying circuit and functioning as a second output terminal of the forced resonance injection circuit.
9. A hybrid dc circuit breaker according to claim 7, characterized in that the transformer is coreless.
10. A hybrid DC circuit breaker according to claim 5, characterized in that the polarity module comprises:
a first switching transistor and a second switching transistor which are connected to form a first bridge arm, wherein a first node formed by connecting the first switching transistor and the second switching transistor is used as the first polarity terminal;
a third switching transistor and a fourth switching transistor which are connected to form a second bridge arm, wherein a second node formed by connecting the third switching transistor and the fourth switching transistor is used as the second polarity terminal;
wherein a first electrode of the first switching transistor and a first electrode of the third switching transistor are connected to a positive output terminal of the rectifier circuit, and a second electrode of the second switching transistor and a second electrode of the fourth switching transistor are connected to a negative output terminal of the rectifier circuit.
11. A hybrid dc breaker according to any of claims 1-3, further comprising a surge arrester connected in parallel with the semiconductor switch.
12. A hybrid dc circuit breaker according to claim 8, wherein said autotransformer is coreless.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120268285.2U CN215733441U (en) | 2021-01-29 | 2021-01-29 | Hybrid direct current breaker |
| EP22153050.4A EP4036949A1 (en) | 2021-01-29 | 2022-01-24 | A hybrid dc circuit breaker |
| JP2022010112A JP2022117469A (en) | 2021-01-29 | 2022-01-26 | Hybrid DC circuit breaker |
| US17/584,938 US11862416B2 (en) | 2021-01-29 | 2022-01-26 | Hybrid DC circuit breaker |
| KR1020220013760A KR20220116099A (en) | 2021-01-29 | 2022-01-28 | Hybrid dc circuit breaker |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120268285.2U CN215733441U (en) | 2021-01-29 | 2021-01-29 | Hybrid direct current breaker |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215733441U true CN215733441U (en) | 2022-02-01 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120268285.2U Active CN215733441U (en) | 2021-01-29 | 2021-01-29 | Hybrid direct current breaker |
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| Country | Link |
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| CN (1) | CN215733441U (en) |
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