CN202276128U - Resonance type DC solid state breaker - Google Patents

Abstract

Disclosed is a resonance type DC solid state breaker, belonging to the solid state breaker field. The resonance type DC solid state breaker comprises a DC source, a main switch unit A, an auxiliary switch unit B, and a load, wherein the main switch unit A comprises a main switch thyristor and a main switch power diode; and the auxiliary switch unit B comprises a first thyristor, a second thyristor, a third thyristor, a fourth thyristor, a first inductance, a second inductance, an energy storage pulse capacitor, and an auxiliary switch power diode. The resonance type DC solid state breaker increases the capacity of the apparatus, decreases the cost, realizes the soft opening (turnoff) of a solid switch, and improves the reliability of the apparatus.

Description

A kind of resonance type DC solid circuit breaker

Technical field

Utility model relates to a kind of solid circuit breaker, relates in particular to a kind of resonance type DC solid circuit breaker.

Background technology

Solid circuit breaker (Solid State Circuit Breaker, be called for short SSCB) is to be used for a kind of novel electric power automation equipment of fast shut-off fault.Use at present many be the alternating current solid-state circuit breaker; Its structure is as shown in Figure 1; It mainly is made up of two parts: the RC buffering absorbs circuit and two anti-and be connected solid-state switches, and wherein, this solid-state switch can be turn-off thyristor GTO (Gate Turn-Off Thyristor; Be called for short GTO) or insulated gate bipolar power tube IGBT (Insulated Gate Bipolar Transistor is called for short IGBT).Because of the overload capacity of existing normal power device lower; So solid circuit breaker is normal to be made up to make with flow restricter and is used for realizing the failure on-off under the short-circuit conditions; Its structure is as shown in Figure 2, and it mainly is made up of main switch unit A (GTO forms), current limliting unit and zinc oxide arrester unit.During operate as normal, GTO is in conducting state; When breaking down, GTO breaks off rapidly, and fault current flows through current limiting reactor, and zinc oxide arrester will limit the rate of voltage rise at two ends, current limliting unit, and voltage is added in two ends, current limliting unit, thereby has limited fault current.But this solid switchgear that is made up of full control device is applied to the AC distribution net mostly, then has following problem when being applied to direct current network:

(1) no natural zero-crossing point in the DC line, the electric current that flows through is a steady state value, does not exist in the possibility that the zero crossing annex is controlled.The electric current, the voltage stress that when solid-state switch (like GTO, IGBT) moves, bear are very big, and existing device generally is difficult to satisfy.This just requires these characteristics to direct current, and the electric current that solid-state switch bears when slowing down device action (pressure) stress avoids damaging device.

(2) overload capacity of existing power device is lower, breaking capacity is less than normal, and the overload magnification that device can bear is less.When the electric current that flows through is big, need carry out several times derate use to device, the waste that causes device to use need provide reliable driving and synchronous control technique simultaneously.

(3) adoptable full control device on-state loss such as GTO, IGBT is big.Can pass through the about 2V of on-state voltage drop of the high-power gto of 2kA at present, loss is about 4kW when normally moving, and need adopt a plurality of devices to carry out series and parallel in high pressure, big current applications occasion, and loss is considerable, has also increased the heat radiation requirement and the operation cost of device.

These several problems all are not well solved at present, have therefore limited the application of solid circuit breaker in the direct current field.

The utility model content

The utility model purpose is to the defective that prior art exists a kind of resonance type DC solid circuit breaker to be provided; Change existing circuit structure; With electric current (pressures) stress that avoids the use of expensive full control device and bear in switch motion moment excessive with the low restriction that solid circuit breaker is used of overload capacity, the soft of solid circuit breaker opened and soft shutoff in realization.

The utility model adopts following technical scheme for realizing above-mentioned purpose:

The utility model resonance type DC solid circuit breaker; Comprise DC power supply and load; It is characterized in that also comprising main switch unit A and auxiliary switching element B; Wherein main switch unit A comprises: main switch thyristor and main switch power diode, auxiliary switching element B comprise first thyristor, second thyristor, the 3rd thyristor, the 4th thyristor, first inductance, second inductance, energy storage pulsed capacitance and auxiliary switch power diode; The positive output end of DC power supply connects the anode of first thyristor, the anode of main switch thyristor and the negative electrode of main switch power diode respectively; The negative output terminal of DC power supply is connected ground connection with the anode of auxiliary switch power two utmost points, the negative electrode of the 4th thyristor and the negative input end of load respectively; The anode of main switch power diode connects the negative electrode of main switch thyristor, the positive input terminal of load, the negative electrode of second thyristor and the negative electrode of the 3rd thyristor respectively; The negative electrode of first thyristor connects the anode of second thyristor and the input of first inductance respectively; The output of first inductance connects the input of second inductance and the input of energy storage pulsed capacitance respectively; The anode of output termination the 3rd thyristor of second inductance, the output of energy storage pulsed capacitance connect the anode of the 4th thyristor and the negative electrode of auxiliary switch power diode respectively.

The beneficial effect of the utility model is following:

1, from the loss of switch motion instantaneous power device; The low shortcoming of device overload magnification set point when adopting the thought of resonant type soft-switch to avoid opening firmly damage that (shutoffs) cause power device and shutoff; Made the zero crossing in direct current field; Realize soft the opening (shutoff) of power device, improved the reliability of device.

2, the power device from adopting; Saved the expense that adopts expensive full control power device (like GTO, IGBT); Increased the capacity of device; On-state loss, heat radiation requirement, manufacturing expense and the operation cost of device have been reduced, because the triode thyristor SCR (Silicon Controlled Rectifier) that the utility model adopts is the maximum and minimum device of on-state voltage drop of single tube capacity in the power device of existing market use.

3, from concerning the requirement of driving power, only need provide the pulse of certain width to get final product during the SCR conducting, need not driving power after the conducting energy is provided again.If adopt full control device, need continue to provide energy to the control circuit of power device, can require with regard to strictness getting of high potential driving power in that high-voltage field is fashionable.

4, from the autgmentability of circuit structure; What adopt at present is this half control device of SCR; According to the difference of application scenario, some occasion can substitute with full control device, along with the development of power device and semi-conductor market; This alternative possibility exists, and the rapidity that substitutes the back device will improve a lot.

In sum, the DC solid circuit breaker that the utility model proposes not only adopts the market-oriented device that this present capacity of SCR is maximum, on-state voltage drop is minimum; Improved the capacity of device; Reduce cost, and realized soft the opening (shutoff) of solid-state switch, improved the reliability of device.

Description of drawings

Fig. 1: alternating current solid-state breaker circuit figure;

Fig. 2: the case history circuit diagram that solid circuit breaker and flow restricter combination are used; Sign is respectively: 1 buffer, 2 lightning arresters, 3 reactors, 4 switches

Fig. 3: the main circuit structure figure of the DC solid circuit breaker of the utility model design;

Fig. 4: the another kind of type of service of the energy bleed off of the DC solid circuit breaker of the utility model design;

Fig. 5: normally turn on and off time sequential routine figure;

Fig. 6: time sequential routine figure is turn-offed in short circuit;

Embodiment

Be elaborated below in conjunction with the technical scheme of accompanying drawing to utility model:

As shown in Figure 1, be alternating current solid-state breaker circuit figure, Fig. 2 is the case history circuit diagram that solid circuit breaker and flow restricter combination are used.

The circuit of the utility model is as shown in Figure 3, and wherein A is the main switch unit, and B is an auxiliary switching element.Wherein main switch unit A comprises: main switch thyristor T ₁₁With main switch power diode D ₁Auxiliary switching element B is mainly by the first thyristor T ₂₁, the second thyristor T ₂₂, the 3rd thyristor T ₂₃, the 4th thyristor T ₂₄, inductance first inductance L ₁, second inductance L ₂, energy storage pulsed capacitance C ₁With auxiliary switch power two utmost point D ₂Form.

Wherein auxiliary switching circuit can be divided into again by function and combination:

(1) the auxiliary circuit of opening: the first thyristor T ₂₁, first inductance L ₁, second inductance L ₂, the 3rd thyristor T ₂₃Constitute;

(2) auxiliary charging circuit: the first thyristor T ₂₁, first inductance L ₁, energy storage pulsed capacitance C ₁, the 4th thyristor T ₂₄Constitute;

(3) normal turn-off circuit: energy storage pulsed capacitance C ₁, first inductance L ₁, the second thyristor T ₂₂, auxiliary switch power diode D ₂Constitute;

(4) overload breaking circuit: energy storage pulsed capacitance C ₁, second inductance L ₂, the 3rd thyristor T ₂₃, auxiliary switch power diode D ₂Constitute.

Below introduce the operation principle of the DC solid circuit breaker of the utility model:

Open the first thyristor T earlier ₂₁With the 3rd thyristor T ₂₃, the zero current turning-on of realization auxiliary switch; When first inductance L of flowing through ₁, second inductance L ₂Electric current reach or during near rated current, open main switch thyristor T ₁₁With the 4th thyristor T ₂₄, commutation course takes place, main switch thyristor T ₁₁Electric current begin to increase gradually energy storage pulsed capacitance C ₁Begin charging; When second inductance L ₂Electric current when being reduced to zero, commutation course finishes, main switch thyristor T ₁₁Electric current reach stationary value.

When solid circuit breaker SSCB needs normal the disconnection, the second thyristor T ₂₂Conducting, energy storage pulsed capacitance C ₁Through first inductance L ₁Discharge, when resonant discharge electric current during greater than load current, main switch thyristor T ₁₁Electric current reduces to zero, main switch thyristor T ₁₁Naturally turn-off owing to bear reverse voltage, unnecessary electric current is from D ₁In return electrical network.When the needs fault is turn-offed, the 3rd thyristor T ₂₃Conducting, energy storage pulsed capacitance C ₁Through second inductance L ₂Discharge second inductance L ₂Value than first inductance L ₁Little, the velocity of discharge when fault is turn-offed is fast during than normal turn-off, works as D ₁In main switch thyristor T when having electric current to flow through ₁₁Naturally turn-off.As main switch thyristor T ₁₁Manage, close naturally and have no progeny, the resonant circuit that electric capacity and inductance are formed is proceeded charge and discharge, for putting into operation of next time prepared.

The another kind of type of service of the energy bleed off of the DC solid circuit breaker that Fig. 4 designs for the utility model.

Circuit working state is analyzed during operate as normal:

In Fig. 5, t ₀Control system is sent SSCB and is normally opened order constantly, triggers the first thyristor T simultaneously ₂₁With the 3rd thyristor T ₂₃Conducting is because inductance L ₁And L ₂Existence, T ₂₁And T ₂₃Realized zero current turning-on.After this, flow through inductance L ₁And L ₂In electric current increase gradually, up to t ₁Constantly reach stable.Suppose that supply voltage uses V _DcExpression, load resistance is used R _LoadSwitch T is not considered in expression ₂₁And T ₂₃On-state voltage drop and the loss of circuit, the electric current of circuit is:

$i_{L1}\left(t\right)=i_{L2}\left(t\right)=I_N[1-e^{-\frac{{\mathrm{<figure-callout\; id="1"\; label="R\; load\; L"\; filenames="HSA00000573582900032.png"\; state="\{\{state\}\}">R</figure-callout>}}_{\mathrm{load}}}{L_{}}(t-t_0)}]$

t ₁Constantly flow through inductance L ₁, L ₂Electric current finally reach I _L1(t ₁)=I _L2(t ₁)=I _N, can trigger main switch thyristor T this moment simultaneously ₁₁With the 4th thyristor T ₂₄Conducting.Main switch T ₁₁The electric current increase of starting from scratch, T ₁₁Realize zero current turning-on.T ₁₁When tube current increases, first inductance L ₁With capacitor C ₁Resonance is to capacitor C ₁Charge capacitor C ₁The voltage at two ends is from U _C1(t ₁)=0 gradually, and is stable until becoming.The 3rd thyristor T ₂₃Owing to bear reverse voltage, electric current reduces gradually, and this process flows through thyristor T ₂₃Electric current can be expressed as:

$i_{T23}\left(t\right)=i_{L2}\left(t\right)=I_N-\frac{V_{\mathrm{dc}}}{L_2{\mathrm{\&omega;}}_r}\sin \left[{\mathrm{\&omega;}}_r(t-t_1)\right]$

Wherein ${\mathrm{\&omega;}}_r=\sqrt{({\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000573582900032.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+L_2)/L_1{L}_2{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HSA00000573582900032.png"\; state="\{\{state\}\}">C</figure-callout>}}_1}.$

t ₂Constantly, flow through thyristor T ₂₃Electric current I _T23(t ₂)=0, thyristor T ₂₃Naturally turn-off main switch T ₁₁The middle constant load current that equals of current constant is I _T11(t ₂)=I _NGuarantee thyristor T ₂₃Reliable turn-off needs to satisfy:

0＜cos[ω _r(t ₂-t ₁)]＜1

t ₃Constantly, capacitor C ₁Charging current I _C1(t ₃)=I _L1(t ₃)=0, the first thyristor T ₂₁With the 4th thyristor T ₂₄Naturally turn-off, so far capacitor C ₁Charging accomplish, opening process finishes, switch gets into normal operating condition.

Circuit working state is analyzed during normal turn-off:

In Fig. 5, t ₃To t ₄In time period, I _T11(t)=I _N, u _C1(t)=U _C1(t ₃), circuit is in normal operating condition.If t ₄It is the initial moment of normal turn-off process constantly.

t ₄Control system is sent normal turn-off order, the second thyristor T constantly ₂₂Conducting, capacitor C ₁Begin discharge, flow through first inductance L ₁Electric current start from scratch and reverse increase I _T22(t ₄)=I _C1(t ₄)=I _L1(t ₄)=0, thyristor T ₂₂Zero current turning-on.t ₄～t ₅Time period is that the resonant discharge electric current provides electric current to load jointly with the electric current that flows through main switch T11, along with the increase of resonant discharge electric current, capacitor C ₁The voltage at two ends begins to descend, and flows through main switch T ₁₁Electric current also reduce gradually.t ₅Constantly, the resonant discharge electric current equals nominal load current, | I _L1(t) |=I _N, and flow through main switch T ₁₁Electric current I _T11(t ₅)=0, main switch T ₁₁Naturally turn-off, simultaneously the first diode D ₁Electric current from I _D1(t ₅)=0 begins to increase.After this, resonance current begins greater than nominal load current, and unnecessary electric current is from diode D ₁In flow away.t ₆Constantly, capacitor C ₁Discharging current to equal nominal load current again be I _L1(t ₆)=I _N, flow through diode D ₁Electric current to become 0 be I _D1(t ₆)=0.After this, inductance L ₁And capacitor C ₁The resonance branch road that constitutes continues discharge, capacitor C ₁Middle energy stored is divided into two parts: a part is consumed by load, and a part is stored inductance L ₁In.t ₆～t ₇The time period circuit is in LC resonant process, t ₇Resonant process finishes constantly, normally cut-offs release.

Circuit working state was analyzed when short circuit was turn-offed:

For the integrality of maintained switch operating process, use t ₄' represent the initial moment that short circuit is turn-offed constantly, as shown in Figure 6.

t ₄' the moment is flow through main switch T ₁₁Electric current I _I11(t ₄')=I _N, t ₄' back loading begins to occur overcurrent, flows through main switch T ₁₁Electric current increase gradually.

t ₅' constantly, flow through main switch T ₁₁Electric current reach the short circuit current protection multiple of setting, trigger the 3rd thyristor T ₂₃Open-minded, capacitor C ₁Begin discharge, flow through the 3rd thyristor T ₂₃Electric current

I _T23(t ₅')=I _C1(t ₅')=0, because the rising of the speed of discharging current is very fast, flow through main switch T ₁₁Electric current begin to descend.

t ₆' constantly, the discharging current of resonance branch road flows through main switch T greater than load current ₁₁Electric current be reduced to 0, main switch T ₁₁Naturally turn-off the antiparallel first diode D ₁Begin to flow through electric current

I _D1(t ₆')=I _D1(t ₇')=0, part energy is through diode D ₁Begin to feed back to electrical network;

t ₇' constantly, D ₁Electric current is reduced to 0 in the pipe, and its afterflow process finishes; t ₈' constantly, flow through diode D ₂Electric current I _D2(t ₈')=0, resonant process finishes.t ₇'～t ₈' the time period can be regarded capacitor C as ₁, inductance L ₂, thyristor T ₂₃, diode D ₂The resonant tank that constitutes in the charge and discharge process.

The parameter that designs in the instance of the utility model:

Line voltage distribution V _Dc=1kV, circuit rated current I _N=100A; Load resistance R _Load=10 Ω;

Pulse storage capacitor C ₁=200 μ F, inductance L ₁=4mH, L ₂=150 μ H.

Claims (1)

1. a resonance type DC solid circuit breaker comprises DC power supply and load, it is characterized in that this solid circuit breaker also comprises main switch unit (A) and auxiliary switching element (B), and wherein main switch unit (A) comprising: main switch thyristor (T ₁₁) and main switch power diode (D ₁), auxiliary switching element (B) comprises the first thyristor (T ₂₁), the second thyristor (T ₂₂), the 3rd thyristor (T ₂₃), the 4th thyristor (T ₂₄), the first inductance (L ₁), the second inductance (L ₂), energy storage pulsed capacitance (C ₁) and auxiliary switch power diode (D ₂); The positive output end of DC power supply meets the first thyristor (T respectively ₂₁) anode, main switch thyristor (T ₁₁) anode and main switch power diode (D ₁) negative electrode, the negative output terminal of DC power supply respectively with auxiliary switch power diode (D ₂) anode, the 4th thyristor (T ₂₄) negative electrode and the negative input end of load be connected ground connection, main switch power diode (D ₁) anode meet main switch thyristor (T respectively ₁₁) negative electrode, the positive input terminal of load, the second thyristor (T ₂₂) negative electrode and the 3rd thyristor (T ₂₃) negative electrode, the first thyristor (T ₂₁) negative electrode meet the second thyristor (T respectively ₂₂) the anode and the first inductance (L ₁) input, the first inductance (L ₁) output meet the second inductance (L respectively ₂) input and energy storage pulsed capacitance (C ₁) input, the second inductance (L ₂) output termination the 3rd thyristor (T ₂₃) anode, energy storage pulsed capacitance (C ₁) output meet the 4th thyristor (T respectively ₂₄) anode and the negative electrode of auxiliary switch power diode (D2).

Images