CN204144918U - The DC circuit breaker that a kind of high frequency switch power supply system uses - Google Patents

Abstract

The utility model is the DC circuit breaker that a kind of high frequency switch power supply system uses, be made up of insulation crust, final controlling element and switch contact, power supply terminal, load wiring terminal and controller, described controller (4) comprises current collecting device, voltage collecting device and signal processing apparatus, current data in described current collecting device acquisition circuit, described voltage collecting device gathers the voltage data of power end; Described signal processing apparatus is by current collecting device, the electric current of voltage collecting device real-time monitoring system and voltage signal, when load end breaks down electric current, described signal processing apparatus monitors the change of curtage signal, and backward final controlling element (5) sends the signal of cut-off switch contact as calculated.The technical program makes hardware cost reduce, and avoids the waste of the energy; The reliability of equipment is improved, and can not cause circuit breaker misoperation; Complete defencive function can both be realized in all cases.

Description

The DC circuit breaker that a kind of high frequency switch power supply system uses

Technical field

The utility model relates to low-voltage electrical field; especially the DC circuit breaker that a kind of high frequency switch power supply system uses is related to; for the high-frequency model power supply with overcurrent protection or cause electric power output voltage to decline due to short circuit system in; prevent high-frequency model electric power output voltage abnormal, ensure that other parallel branch power consumption equipments normally work.

Background technology

In electric power supply plant and transformer substation communication integrated power supply, AC power is converted to 110V or 220V DC power supply by rectification, supplies DC control equipment and communication equipment after battery charging energy storage.By carrying out unified management to each sub-power supply system, optimizing work flow and deployment of human resources, reducing operation expense, improve the O&M efficiency of power communication.Communication equipment power supply is realized by DC/DC high-frequency model power supply; by high-frequency model power supply, 110V/220V DC power supply is converted to the spendable-48V power supply of communication equipment; because DC/DC high-frequency model power supply itself is with overcurrent protection function, general maximum output current is no more than 1.2 times of output-current rating.Under modular power source (group) exports terminal short-circuit situation, the synchronous decline of output current and voltage can be caused, the harm caused thus is in the system of multi-communication devices parallel operation, if can not disengagement failure loop in time, high-frequency model electric power output voltage can be caused to decline, affect other loop normal loads to power, seriously can make systemic breakdown.

The patent of invention of Authorization Notice No. CN 101976816 B, a kind of overload protection method and device are applied for, by gathering real-time current, voltage data in current supply circuit, calculate instantaneous power and average power that current supply circuit exports, instantaneous power exceedes the Instantaneous peak power thresholding that presets or average power and within a period of time, continues to exceed the average power threshold preset then cut off current supply circuit; When described instantaneous power exceedes described average power threshold and is less than described Instantaneous peak power thresholding, then export user's information.Relative electro-magnetic circuit breaker; can by treating with a certain discrimination instantaneous power and average power overload; and equipment big current starts and the identification of line short feature; realize current supply circuit protecting control more accurately, under the prerequisite ensureing loop power consumption equipment and electric power cable safety, effectively reduce the probability of protective device misoperation.The method have employed bearing power as overload basis for estimation; in the power-supply system of band current-limiting function; after there is short trouble in load; electric current and voltage can synchronously decline; actual measurement power can be less than rated power; whether load end exists fault to utilize power can not correctly judge, can not meet the overload protection of the power-supply system of band current-limiting function.

The patent No. is the patent of invention of CN 101346863 B; apply for a kind of protected location for ac/dc low-voltage power supply line; its direct current overcurrent protection function utilizes shunt to realize the collection of DC current signal, and controller power source provides via network electric power, the electric supply installation that is derived from line voltage (VL).In the power-supply system of band current-limiting function; when being less than power-supply system restriction output current when occurring being greater than rated current; the method can normally be protected; when load is short-circuited fault; electric power outputting current with current-limiting function reduces; shunt the electric current collected and be less than operating current, can tripping occur and lose protective effect.

The patent No. is the patent of invention of CN 101552160 B, apply for a kind of circuit protecting switch with overrun control, utilize pressure drop on shunt as delays time to control and driving power, current sample is realized with electromagnetic structure, achieve the short circuit short time-delay function of the direct current had nothing to do with supply voltage, ensure that the alternative of this system, the closed loop current that all relies on of shunt pressure drop and electromagnetic structure carrys out practical function, power-supply system with current-limiting function is under overload or short-circuit conditions, larger short circuit current can not be provided, now do not possess the operation condition of the mode that this patent provides, circuit breaker tripping.Complete overload protection cannot be realized.

The patent No. is the patent of invention of CN 102568940 A, apply for a kind of delay protection drive circuit of low voltage operating, the principle of the pressure reduction utilizing electric current to produce through shunt is sampled to current signal, and using the working power as controller and executive component after voltage signal boosting, achieve the short circuit short time-delay defencive function of the direct current had nothing to do with supply voltage, because signal and controller power source all depend on loop current size, when high frequency power module or the load of low-power battery group are short-circuited, power source internal with current-limiting function is protected, the electric current that shunt collects is less than operating current, do not meet the operation condition of the guard method that this patent provides, the integrality of overload protection cannot be realized.

The patent No. is the utility model patent of CN 2924773Y; apply for a kind of small-sized circuit breaker overcurrent protection device; by shunt, loop current is sampled; sampling exports the input connecting comparing unit; comparing unit realizes overcurrent protection through logical calculated; this patent only relies on current sample to judge loop load situation; can only protecting the situation of transshipping or after short circuit, fault current is greater than normal current, can not realizing being with the power supply of current-limiting function and the overload of equivalent current supply system and short circuit to carry out complete preservation.

Above patent all proposes different solutions to overload protection in low-voltage electric system; wherein four patents only gather the foundation of bus current as overload protection; a patent adopts power to protect overload; all the power-supply system that loop current after overload increases can only be protected, the overload protection of the power-supply system of band current-limiting function can not be met.

At present in power plant and transformer substation communication integration power-supply system; the high-frequency model power supply adopted is the power module of band current-limiting function; for preventing short circuit from causing other shunt load cisco unity malfunctions, the Normal practice of employing be strengthen modular power source with bearing power ratio, reduce the mode moving multiple and storage capacitor in parallel wink of circuit breaker to improve the success rate of breaker protection function.General Requirements power source loads power ratio is not less than 4:1, and employing instantaneous trip electric current is the Type B circuit breaker between 3In ~ 5In.

There is following problem in such scheme:

Hardware cost increases

Strengthen power source loads power ratio and increase storage capacitor, not only causing the increase of device hardware cost, too increase equipment volume, when normally working, only make use of 25% of source nominal power, causing the waste of the energy.

Reliability is low

Communication Power Equipment is capacitive load, and capacitive load needs when powering on capacitor charging, and transient current is very large, after the Type B circuit breaker that employing wink streaming current is less, can cause circuit breaker misoperation when giving the larger device power of load capacitance.

Protect imperfect

Increase storage capacitor; only defencive function can be realized for during location of short circuit distance storage capacitor closer distance; when short dot distance storage capacitor is far away; due to the metering function of wire internal resistance; the electric current flowing through circuit breaker may not reach and Type B circuit breaker wink moves requirement, and circuit breaker misaction can occur equally.

Summary of the invention

In view of above-mentioned, for the deficiencies in the prior art, there is provided one not by increasing power source loads power ratio and not increasing external capacitive, can realize being short-circuited and can the circuit breaker of open failure load in time under overload situations, guarantee the normal work of other parallel branch power consumption equipments, and the misoperation that when can effectively avoid capacitive load to power on, various situation may cause.

In order to realize the purpose of this utility model, following technical scheme is proposed:

The DC circuit breaker that high frequency switch power supply system uses, is made up of insulation crust, final controlling element and switch contact, power supply terminal, load wiring terminal and controller;

Described controller 4 comprises current collecting device, voltage collecting device and signal processing apparatus, the current data in described current collecting device acquisition circuit, and described voltage collecting device gathers the voltage data of power end; Described signal processing apparatus is by current collecting device, the electric current of voltage collecting device real-time monitoring system and voltage signal, when load end breaks down electric current, described signal processing apparatus monitors the change of curtage signal, and backward final controlling element 5 sends the signal of cut-off switch contact as calculated.

Described DC circuit breaker also comprises an energy storage device, and described energy storage device carries out energy storage when power supply electrifying, major loop be short-circuited cause supply voltage to decline time, provide energy to controller and final controlling element.

Described current collecting device is shunt 3) described shunt 3 is for having the electric conductor of predetermined resistance.

Described controller 4 also comprises:

Power-switching circuit, is connected with power supply terminal by diode, and the Power convert from major loop is become low-voltage dc power supply, for signal processing circuit and final controlling element provide energy;

Current signal change-over circuit, converts the acceptable voltage signal of logic control circuit to the current signal from current collecting device;

Voltage signal change-over circuit, directly or be connected with the positive pole of power input by diode, the high voltage signal of input, is converted to the discernible low-voltage signal of logic control circuit;

Logic control circuit: the signal provided for receiver voltage and current converter circuit, by logical calculated and according to result of calculation start final controlling element, complete defencive function;

Executive circuit, for accepting the signal of logic control circuit, and according to signal controlling final controlling element 5.

Described energy storage device and power circuit share smothing filtering electric capacity.

The utility model has following beneficial effect:

Power and the bearing power ratio of effective reduction integration power-supply system, reduce system bulk, also reduce energy consumption during system cloud gray model simultaneously, reach the object of environmental protection while minimizing hardware cost;

Effectively can avoid the misoperation when the load that capacitive is larger powers on and the refused action when the place's short circuit of long distance rate wire, achieve integrality and the reliability of protection.

Accompanying drawing explanation

Fig. 1 is the utility model circuit breaker system schematic diagram;

Fig. 2 is the structure principle chart of controller;

Fig. 3 Fig. 3 is algorithm flow chart of the present utility model;

Fig. 4 is capacitive load electric current and voltage change waveform when powering on;

Fig. 5 is the voltage-current curve figure of capacitive overload load powered on moment;

Fig. 6 load is far longer than current/voltage change waveform during the specified output loading of power supply;

Fig. 7 is impedance typical change curve chart.

Embodiment

Fig. 1 is circuit breaker system schematic diagram, current signal utilizes the shunt 3 being serially connected in negative pole to sample, voltage signal is sampled to the voltage be connected between power end positive terminal 1 and negative terminal 2, by sampling respectively to the voltage on shunt 3 two ends and the voltage signal between positive terminal 1 and negative terminal 2, calculated by controller 4 pairs of load impedances, first the current signal collected is utilized to judge, if when load current occurs being greater than operating current, circuit breaker is directly protected according to load current value, if the overload that circuit breaker load end occurs causes supply voltage to decline, then protect according to load.When load current (load impedance) meets operation condition, controller 4 drives executive component 5, pushing mechanism, reaches the object of circuit breaker disjunction.

At capacitive load powered on moment, the instantaneous increase of loop current can be made to the charging process of electric capacity, when capacitive load is larger, modular power source output voltage also can be caused to decline, this process and load short circuits or overload situations similar.With short circuit unlike the charging complete along with electric capacity, charging current reduces gradually, modular power source output voltage also can recover normal gradually, now load impedance also recovers normal, because the size of charging current is by modular power source power and wire internal resistance, wire internal resistance is by conductor length, wire diameter, the impact of wire conductance, when equal modules power supply connects with the wire that wire internal resistance is different, such as different transmission ranges, curent change curve when now load powers on is different, when wire internal resistance is less, peak current is larger, the time that current stabilization needs is shorter, it is contrary to wire internal resistance is larger, peak current is less, the current stabilization time is longer.Exceed operating value for preventing the capacitive load charging current that powers on and misoperation occurs, controller is in Logic judgment, not only rely on load impedance value size as action whether basis for estimation, also adopt impedance variation trend curve as basis for estimation simultaneously, after load impedance variation tendency is steady, carry out judging whether to there is overload situations according to load real impedance values again, can effectively avoid like this powering on the circuit breaker misoperation that may cause due to capacitive load.

Circuit breaker upper end connect DC/DC or the AC/DC power supply that power supply is electronic type, under large capacitive load electrifying condition, the phenomenon of similar short circuit can be caused, namely transient current increase, voltage drop.For preventing circuit breaker generation misoperation in the case, in control logic, add electric current (load) variation tendency judge, when the electric current/load of the appearance in load is greater than action setting threshold, also to calculate its change curve, change curve in downward trend time, may be that the electric current (load) that capacitive load power up causes increases, now breaking operation is not carried out to circuit breaker, if capacitive load powers on, along with completing of capacitor charging, electric power outputting current recovers normal gradually, when judging according to electric current (load) actual size again after load stabilization.This makes it possible to effectively avoid circuit breaker contingent misoperation when capacitive load powers on.

Controller 4 implementation is shown in Fig. 2, controller power circuit is directly supplied by the power supply be connected between power end positive terminal 1 and negative terminal 2, cathode power supply is connected to power supply chip 42 input after counnter attack diode 41, supply control circuit after power supply chip 42 step-down, power supply after step-down carries out energy storage through the storage capacitor of power supply chip 42 to power supply energy, for control circuit and execution short circuit provide energy, prevent the communication power supply circuit breaker tripping that modular power source decompression causes controller dead electricity to cause when circuit breaker sealing short circuit.

Voltage between voltage sampling circuit 43 pairs of power end positive terminal 1 of power supply and negative terminal 2 is sampled, voltage sampling circuit 43 connects counnter attack diode 41 anode, after electric resistance partial pressure process, directly give the AD conversion unit of MCU in controller 4 signal processing circuit 46, complete the sampling to voltage.The pressure drop that current sampling circuit 44 utilizes electric current to be produced by resistance, the voltage at shunt 3 two ends being serially connected in power cathode is sampled, sampled signal connects differential amplifier circuit 45, to the AD conversion unit giving MCU in controller 4 signal processing circuit 45 after voltage signal process.

Logic control element in signal processing circuit 46 receives the signal of two-way AD conversion unit, pass through algorithm calculations, calculate the actual voltage value in loop and current value respectively, and calculate loop load impedance according to electric current and voltage value, after logical calculated, control executive component.

The know-why of overload protection arrangement of the present utility model utilizes load impedance overload basis for estimation, by gathering load current and bus bar circuit voltage, load real impedance values is calculated according to Ohm's law, through contrasting with specified action impedance, when load impedance is less than specified operating value, breakdown judge is made to load, consider the impact of capacitive load on the power-supply system of band current-limiting function, increase impedance or change in voltage trend are as auxiliary judgment condition, when load impedance or supply voltage are when changing to normal value, can think that load is capacitive load, wait for that load impedance or supply voltage judge after stablizing again.

The utility model is protected overload by the form detecting load impedance.Need to gather voltage U between bus current I and bus; load impedance value Z is calculated according to Ohm's law; the actual loading impedance Z that calculating obtains and specified action impedance Ze make comparisons; when load practical impedance Z is less than specified action impedance Ze; again according to voltage U (or impedance Z) variation tendency, determine whether that capacitive load powers on the short-time overload caused, to power on the short-time overload caused if not capacitive load; disengagement failure loop, protects power-supply system.

The impact brought to prevent sampling error, has carried out digital filtering process to the sampled data of loop current and supply voltage.

The algorithm flow chart of Fig. 3 this programme, after system electrification initialization completes, voltage U 0 and electric current I 0 is gathered in the t0 moment, calculate load impedance value Z0=U0/I0 now, if Z0 is greater than specified action impedance value Ze, current data is gathered and voltage data obtains new Z0 after time t, if Z0 is less than specified action impedance value Ze, after time t, gather current data and voltage data I1 and U1 and calculate the resistance value Z1 in t1 moment, calculate the difference Ri=Zi-Zi-1(i=1 between adjacent twice resistance value ... .N), and compare with undulating value d, if Ri >=| d| (i=1 ... .N), think that load is in T1 or the T2 stage, the T1 stage is the process that load loads or impedance of breaking down reduces, this process time is shorter, the T2 stage is the stable gradually process of load, the comprehensive function of load capacitance and short-circuit impedance is subject in section at this moment, resistance value is in rising trend, now do not judge whether there is load fault, as a N continuous Ri < | then think during d| that load end exists overload fault, export control signal, complete and once protect, wherein, N can be defined as 3.In computational process, can using current value as householder method, determination methods is identical with resistance value judgment mode, repeats no more here.

Power-supply system with current-limiting function has following characteristics: need first to the capacitor charging of device interior when capacitive load powers on, when it powers on, momentary load impedance is short-circuit condition, power source internal capacitor discharge, transient current is much larger than rated current, voltage drop, close to 0V, along with the charging process of electric capacity completes, is tending towards normal after loop current reduces gradually, voltage rises to load voltage value gradually, and electric current and voltage change oscillogram is shown in Fig. 4; When there is the load of capacitive overload in load, powered on moment electric current and voltage change curve is the same with normal load change curve, current/voltage is stabilized to stationary value, different with power conditions according to overload situations, multiple situation may be there is in output voltage and output current, but its resistance value value is less than rated impedance, Fig. 5 is the voltage-current curve figure that voltage reduces that electric current increases situation; In a short-circuit situation, because load is far longer than the specified output loading of power supply, powered on moment power source internal capacitor discharge, cause the transient current much larger than rated current, then supply voltage can be reduced to stationary value rapidly, the size of stationary value is relevant with the size of short circuit load, and current/voltage change oscillogram is shown in Fig. 6.Transient current is all there is excessive when capacitive load under any circumstance powers on, the situation that voltage reduces, test load resistance value is much smaller than rated impedance value, for preventing causing misoperation in capacitive load power up, in breakdown judge process, increase that change in voltage trend is auxiliary carries out Logic judgment, when after load impedance value diminishes suddenly, voltage is in increase tendency gradually, now do not do troubleshooting to load to judge, after waiting for load stabilization, carry out Logic judgment according to the load impedance value after stable again, determine whether there is load fault in loop.

Embodiment 1

According to the structure principle chart of the controller of Fig. 2, the shunt 3 pairs of electric current I being serially connected in negative pole are utilized to sample, electric resistance partial pressure is utilized to sample to the voltage U between power end positive terminal 1 and negative terminal 2, load impedance Z is obtained through algorithm calculations, impedance typical change curve is shown in Fig. 7, the T1 stage is the process that load loads or impedance of breaking down reduces, this process time is shorter, the T2 stage is the stable gradually process of load, the comprehensive function of load capacitance and short-circuit impedance is subject in section at this moment, resistance value is in rising trend, the length of transformation period is by load capacitance and short-circuit impedance and power multifactor impact, this phases-time is likely shorter, even overlap with the follow-up T3 stage, the T3 stage is the impedance stabilization stage, along with stablizing of system, resistance value is invariable, whether can there is overload fault to load end in this stage to judge, if in this stage, there is fault in load, then send fault-signal, outwardly signal is sent by the executive component 5 in Fig. 2, this signal can provide high frequency electric source or other watch-dogs or switch element, realize system monitoring or protection.

Embodiment 2:

With embodiment 1, as impedance Z≤Ze or/and electric current I >=Ie time, judge whether electric current I reaches stable, when electric current I does not reach stationary value, think that load is in changes phase, judge loading condition according to resistance value and/or current value after electric current recovery is stable, determination methods is identical with embodiment 1, repeats no more here again.

Embodiment 3:

With embodiment 1, as impedance Z≤Ze or/and electric current I >=Ie time, judge whether voltage U reaches stable, when voltage U does not reach stationary value, think that load is in changes phase, judge loading condition according to resistance value and/or current value after voltage resume is stable, determination methods is identical with embodiment 1, repeats no more here again.

Above-described embodiment is only for being described the utility model but not limiting the utility model; therefore; for a person skilled in the art; when not deviating from the utility model spirit and scope, various apparent change is carried out to it, all should within protection range of the present utility model.

Claims (5)

1. a DC circuit breaker for high frequency switch power supply system use, is made up of insulation crust, final controlling element and switch contact, power supply terminal, load wiring terminal and controller, it is characterized in that:

Described controller (4) comprises current collecting device, voltage collecting device and signal processing apparatus, the current data in described current collecting device acquisition circuit, and described voltage collecting device gathers the voltage data of power end; Described signal processing apparatus is by current collecting device, the electric current of voltage collecting device real-time monitoring system and voltage signal, when load end breaks down electric current, described signal processing apparatus monitors the change of curtage signal, and backward final controlling element (5) sends the signal of cut-off switch contact as calculated.

2. DC circuit breaker as claimed in claim 1, it is characterized in that, described DC circuit breaker also comprises an energy storage device, and described energy storage device carries out energy storage when power supply electrifying, major loop be short-circuited cause supply voltage to decline time, provide energy to controller and final controlling element.

3. DC circuit breaker as claimed in claim 2, is characterized in that: described current collecting device is shunt (3), and described shunt (3) is for having the electric conductor of predetermined resistance.

4. DC circuit breaker as claimed in claim 3, is characterized in that: described controller (4) also comprises:

Power-switching circuit, is connected with power supply terminal by diode, and the Power convert from major loop is become low-voltage dc power supply, for signal processing circuit and final controlling element provide energy;

Current signal change-over circuit, converts the acceptable voltage signal of logic control circuit to the current signal from current collecting device;

Voltage signal change-over circuit, directly or be connected with the positive pole of power input by diode, the high voltage signal of input, is converted to the discernible low-voltage signal of logic control circuit;

Logic control circuit: the signal provided for receiver voltage and current converter circuit, by logical calculated and according to result of calculation start final controlling element, complete defencive function;

Executive circuit, for accepting the signal of logic control circuit, and according to signal controlling final controlling element (5).

5. DC circuit breaker as claimed in claim 4, it is characterized in that, described energy storage device and power circuit share smothing filtering electric capacity.