CN2457779Y

CN2457779Y - Electronic zero push-pull contactor

Info

Publication number: CN2457779Y
Application number: CN 00249385
Authority: CN
Inventors: 林在荣
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-09-25
Filing date: 2000-09-25
Publication date: 2001-10-31
Anticipated expiration: 2010-09-25

Abstract

The utility model discloses an electronic zero switching contactor. An attached digital logic circuit and an electric electronic element are used for bearing the transient process of a strong electricity circuit in a line at the moment of power supply or power cut of the contactor; after the transient process is finished, the contactor is used for running, the electric electronic element quits running, and thereby, the goal of zero switching is achieved. The whole system of the utility model comprises the digital logic circuit, namely, a stable command trigger circuit and a transient command trigger circuit, a thyristor transient access circuit, and a contactor stable access circuit. The utility model has the maximum advantage that with the attached digital logic circuit, the utility model solves the problem that the contactor produces a large surge electric current when the power is switched on and produces a drawing arc when the power is switched off. The production and the use of the utility model can improve electric service life and the reliability of the traditional contactor.

Description

Electronic zero cut-in and cut-off contactor

The utility model relates to a kind of brand-new electronic type A.C. contactor that has merged power electronic technology, is suitable for industry and civilian various occasion, belongs to the low voltage electrical apparatus technology field.

In electrician and electric power system, for voltage loss that reduces circuit and the power factor that improves power circuit, almost reactive power automatic compensator all must be installed by the requirement of power supply department in each tame factory, enterprise, building.Its electrical principle, the load state according to electric power networks drops into or withdraws from electric capacitor in parallel automatically exactly, with the compensating reactive power loss.Owing to be automatic switching, and electrical load is a dynamic process that constantly changes, and causes the switching frequency of electric capacitor will be much higher than manual switching thus.This situation has caused the generation of a technical barrier, and Here it is, and electric capacitor is excessive at the surge current that drops into moment, is difficult to overcome.

Therefore, in power industry, use reactive-load compensator, when dropping into electric capacitor, tend to produce great spark at the contacts of contactor place, when cutting off electric capacitor, cling contact again easily, cause and kill, pine does not open phenomenon.Above-mentioned problem why occurs, be because the intrinsic physical characteristic of capacitor is: the voltage at electric capacity two ends can not transition.Drop into the moment of electrical network at electric capacitor, because its initial state terminal voltage is zero, throw in the electrical network of 220V or 380V voltage quickly, huge surge current will be caused, its amplitude is not when adding other measures, therefore be generally more than 20 times of rated current of devices, cause A.C. contactor and electric capacitor itself to be subjected to heavy current impact and damage.

For addressing this problem, common solution has following two kinds:

(1) adopts the pre-special-purpose contactor of CJ19 type of throwing resistance of band;

(2) adopt bidirectional thyristor to replace the contactor of switching electric capacitor.

Above-mentioned two kinds of schemes all have drawback separately.Because if (1) scheme of employing can not solve the contact burning problem, because it is to utilize mechanical spring to add resistance to drop into simultaneously for three-phase.And in fact; phase difference is 120 degree between every phase, can not guarantee that three phase capacitance every phase when dropping into all guarantees not have the input of surge current, in addition mechanical contactor is because spring newness degree difference; stress is different, can lose the effect of protection contact not burning equally very soon.Evidence, when adopting (1) scheme, its surge current still is 9-10 a times of electric capacitor rated current.

Employing scheme (2) can be brought other side effect although can reduce surge current.Show: at this moment be to replace contactor, the conduction voltage drop about 0.8V is arranged during its conducting, can cause circuit power consumption excessive with bidirectional thyristor.Its two because thyristor has a dead band voltage when zero passage, cause the discontinuity of electric current and voltage, thereby make the bigger harmonic wave composition of generation in the electrical network.Back kind situation is forbidden by strictness in electric power system.Because the mains by harmonics composition is crossed conference and is caused in the electric power system many automatic control equipments malfunctioning, leads to bigger electric power accident.Its three, replace contactor also to cause whole cost too high with bidirectional thyristor fully.

The purpose of this utility model provides a kind of new electronic zero cut-in and cut-off contactor, the transient process that this contactor is switched in the line or moment of cutting off the power supply is born the forceful electric power circuit by additional power electronic element, after treating that transient process finishes, by the contactor row that puts into operation, power electronic element is out of service, thereby reaches the purpose of zero switching.

The great advantage of this technical scheme is: fundamentally solved the huge surge current that contactor produces when energising, the arcing problem that produces during disconnection.Because this contactor has a large capacity and a wide range, in low-voltage circuit, lack it can not, so its production, use can solve the short problem of contactor electric life and improve its reliability, are to have revolutionary variation concerning contactor.

Task of the present utility model is finished like this: 1, before the contactor energising, elder generation with the contacts of contactor shorted on both ends, makes the load surge current pass through via bidirectional thyristor by power electronic element.Connect the contactor power supply then, make the closing of contact, after delay a period of time, thyristor withdraws from.Similar to the above during the contactor outage, also be to connect the bidirectional thyristor that is parallel to the probe of contactor two ends earlier, make the contactor outage again, after delay a period of time, thyristor is out of service.2, the forceful electric power operating part of each phase all is designed to zero-cross triggering circuit.After thyristor conducting control command was sent, this is action immediately mutually, and will arrive this phase voltage zero crossing the time, just began conducting, and surge current almost equates with rated current.3, as the monomer product of contactor, control mode will be oversimplified.For this reason, the utility model adopts the hardware Digital Logical Circuits of being made up of electronic component, finishes the desired work schedule of circuit, and has realized the unification instruction triggers.It triggers and working timing figure is seen Fig. 3 oscillogram.

By the work schedule of Fig. 3 in conjunction with Fig. 1,2,4 electrical schematic diagram as seen, whole electrical schematic diagram is made up of three parts: (1) instruction triggers system; (2) thyristor transient state connecting system; (3) contactor stable state connecting system.

When this electron type operating passing zero contactor receives when dropping into instruction, control logic at first starts bidirectional thyristor makes it conducting, at this moment the contact of contactor access failure still, huge surge current passes through from thyristor one side, subsequently, control logic is connected contactor again, makes it the closing of contact.Because the existing thyristor in two ends, contact is in conducting state before this, so voltage only is about the conducting voltage 0.8V of bidirectional thyristor between the contact of contactor.So contacts of contactor almost is to be in unloaded operation, does not make the contact impaired and can not produce contact spark.A period of time after contactor inserts, thyristor is out of service, and steady-working state is after this born by contactor.Therefore do not produce harmonic wave in the time of can be, disturb electrical network as the thyristor conducting.When control logic is sent the instruction of cutting off contactor, similar during with input, put into operation by thyristor earlier, contacts of contactor is withdrawed from, as a same reason, because contactor withdraws from moment, thyristor still is in conducting state, therefore, and the arcing phenomenon in the time of can not making contacts of contactor produce outage.Then, postpone a period of time, thyristor is withdrawed from.Since contactor throw and and the moment out of service, its contact all is in zero load condition, so be referred to as " zero cut-in and cut-off contactor ".

The utility model is described in further detail below in conjunction with drawings and Examples.

Fig. 1 is the circuit block diagram of additional character logical circuit of the present utility model.

Fig. 2 is an additional character logical circuit schematic circuit of the present utility model.

Fig. 3 is that contactor of the present utility model triggers and working timing figure.

Fig. 4 is the single-phase heavy-current control of a utility model loop electrical schematic diagram.

Fig. 5 is the utility model three-phase heavy-current control loop electrical schematic diagram.

With reference to Fig. 1, this is a Digital Logical Circuits block diagram of the present utility model, and wherein 1 is the instruction triggers circuit, and 2 is thyristor transient state place in circuit, and 3 is contactor stable state place in circuit.The sequence ligand that connects of above-mentioned three partial circuits is: the input of the output of instruction triggers circuit and thyristor place in circuit joins, and the instruction triggers circuit output end links to each other with the input of contactor stable state place in circuit.

With reference to Fig. 2, the instruction triggers system comprises steady state instruction circuits for triggering and transient state instruction triggers circuit.In the drawings, by NAND gate U2 and not gate U1, and resistance R 2 capacitor C 1 forms the steady state instruction triggering sequential of contactor.Wherein A point and C point sequential chart as shown in Figure 3, the integrating circuit that resistance R 2, capacitor C1 are formed makes C point waveform than A point delay a period of time.Switching by C point Waveform Control contactor.By NAND gate U2, U5 not gate U6 and capacitor C 3, resistance R 6 is formed thyristors and is started sequential and trigger prior to the contactor desired sequential of switching on to guarantee as previously discussed thyristor, and guarantees a period of time after the contactor action, and thyristor withdraws from.By not gate U4 and NAND gate U3, capacitor C 2, the contactor exit instruction sequential that resistance R 2, R3, R4 form.When the A point is imported by high step-down, the E point produces a negative saltus step pulse, make the thyristor triggering and conducting, and continue to contactor outage equally and withdraw from a period of time after the circuit, just make thyristor out of service, above-mentioned oscillogram still as shown in Figure 3, NAND gate U7, not gate U8 guarantee to provide thyristor required sequential at the input of contactor G point when withdrawing from.

Above work schedule both can have been supplied with single-phase forceful electric power loop works, can supply with three-phase forceful electric power loop works again.

Digital Logical Circuits is instruction triggers circuit and thyristor transient state degree place in circuit and contactor stable state place in circuit, the sequence ligand that connects between them is: the input of the output of instruction triggers circuit and thyristor transient state place in circuit joins, and the input of another output of instruction triggers circuit and contactor stable state place in circuit joins.

Digital Logical Circuits comprises steady state instruction circuits for triggering and transient state instruction triggers circuit, described steady state instruction circuits for triggering are by not gate U1, NAND gate U2, resistance R 1, capacitor C1 forms, described transient state instruction triggers circuit is by NAND gate 1U2, NAND gate U3, not gate U4, NAND gate U5, not gate U6, NAND gate U7, not gate U8, capacitor C2, capacitor C3, resistance R 2-R4, resistance R 6 is formed, the relation of joining that connects of foregoing circuit is: an end of resistance R 1 connects the A point, capacitor C2, one end of

resistance R

2 and 2 pin of NAND gate U2, the other end of resistance R 1 and B point, the input of capacitor C1 one end and not gate U1 joins, the other end ground connection of capacitor C1,1 pin of the output of not gate U1 and NAND gate U2 joins, 3 pin of NAND gate U2 and 2 pin of NAND gate U5 join, the output of the 1 pin NAND gate U6 of NAND gate U5 and 1 pin of NAND gate U7, the F point joins, 3 pin of NAND gate U5 and the end of capacitor C3 join, input and resistance R 6 one ends of the other end NAND gate U6 of capacitor C3 join, resistance R 6 other end ground connection, capacitor C2, one end of the other end of resistance R 2 and

resistance R

3 and 2 pin of NAND gate U3 join, one end of the other end of resistance R 3 and resistance R 4 connects power supply jointly, 1 pin of the other end of resistance R 4 and NAND gate U3 joins, the input of the 3 pin NAND gate U4 of NAND gate U3 links to each other, 2 pin of the output of not gate U4 and E point and NAND gate U7 join, the input of the 3 pin NAND gate U8 of NAND gate U7 joins, the output termination G point of not gate U8.

Fig. 4 is the electrical schematic diagram in the single-phase heavy-current control of the utility model loop.

In Fig. 4, by photoelectric coupled circuit U9, bidirectional thyristor U11, resistance R 7, R9, R10, capacitor C 4 has been formed the stable state connecting system of contactor JS, and input control order is provided by the C point.By photoelectric coupled circuit U10, bidirectional thyristor U12, resistance R 8, R11, R12, capacitor C 5 is formed door forceful electric power loop transient state connecting system, and input control order is provided by the G point.Because U9, U10 selects the optic coupling element of zero cross fired for use, can guarantee the whole system operating passing zero, and surge is eliminated.Uin is the input power supply among Fig. 4, and CL is the electric capacitor as load.

With reference to Fig. 5, it is the heavy-current control loop of three-phase electronic operating passing zero contactor

In Fig. 5, among the stable trigger circuit of three-phase contactor and Fig. 4 in the contactor steady-state circuit circuit the same, by optocoupler U13, bidirectional thyristor U14, resistance R 13, R14, R15, capacitor C 6 and three-phase contactor JS3 form.And three-phase transient state place in circuit, with optocoupler U15, U17, U19 is connected into series connection in the importation, and the optocoupler output is divided into three independent links, and each link circuit is the same with transient state place in circuit among Fig. 4, respectively to just answering three groups of contact JA of three-phase contactor, JB, JC.As a same reason, owing to adopted the zero cross fired optic coupling element, can make three groups of contacts of three-phase, respectively conducting when each self-loop zero crossing.

Above Fig. 1, the shown technical scheme of Fig. 2 and Fig. 4 is a most preferred embodiment, Fig. 1, the shown technical scheme of Fig. 2 and Fig. 5 is another embodiment.

The utlity model has wide application prospect.

The first, in the electric power electrician trade, it will eliminate tradition with the Novel electric subtype contactor of electromechanical integration The CJ19 type electric capacitor Special contactor with pre-cast resistance, and replace.

The second, in domestic elevator industry, use in a large number traditional contactor, it is because the frequent starting switching, Pitting of contacts is serious, usually causes elevator faults. Contactor of the present utility model is used for elevator industry, is expected knot Restraint the insecure history of domestic elevator work.

The 3rd, because surge current is a universal phenomenon in electrician trade, the transient current of any electrical equipment usually Several times to tens times of steady-state current, the electronic zero cut-in and cut-off contactor that adopts the utility model patent to make, Can make the electrical endurance of existing contactor prolong more than five times, even its appliance life reaches and mechanical life one Sample long (common contactor standard: electrical endurance be its mechanical life 1/5).

The 4th, if China's electrician trade extensively adopts the utility model patented technology, can be on a large scale energy-conservation With the saving cost. Because after using the utility model patent, the type selecting of contactor can by 1/2 of rated current～1/5 selects. This is because in the design of traditional contactor, bear transient state and stable state owing to will take into account it Two aspect work, have to strengthen design capacity. For example, general A.C. contactor touching when putting into operation Put electric current, be usually designed to 10 to 12 times of its specified steady-state current. The utility model patent adopts now Power electronic element has been born the electric transient working process of conventional contactor. A rated current is 10A's Contactor is even if be used for the workplace of 50A rated current, the also worry of non-contact scaling loss. In addition, because IGCT only is in the transient state conducting state, hardly with considering to adopt cooling measure. On the type selecting of capacity specifications Also can " the big usefulness of small wood ", reduce cost. The more important thing is, unlike adopting solid-state relay, can produce Harmonic wave, thus cause " electropollution ".

Therefore, in the occasion of any use contactor, the novel zero cut-in and cut-off contactor of this class will be little with its power consumption, Do not produce harmonic wave, cost is low, and all advantages such as reliable operation replace traditional A.C. contactor. Thereby, be subjected to The popular welcome of electric power electrician trade.

Claims

1. electronic type operating passing zero contactor, it is characterized in that having added Digital Logical Circuits on its contactor, promptly by the instruction triggers circuit, thyristor transient state place in circuit and contactor stable state place in circuit are formed, the relation of joining that connects of three parts of circuit is to instruct the output of circuits for triggering and the input of thyristor place in circuit to join, and another output of instruction triggers circuit links to each other with contactor stable state place in circuit input.

2. electronic zero cut-in and cut-off contactor according to claim 1 is characterized in that the instruction triggers circuit in the Digital Logical Circuits comprises; Steady state instruction circuits for triggering and transient state instruction triggers circuit two parts, described steady state instruction circuits for triggering, by not gate U1, NAND gate U2, resistance R 1, capacitor C1 forms, described transient state instruction triggers circuit is by NAND gate U2, U3, not gate U4, NAND gate U5, not gate U6, NAND gate U7, not gate U8, capacitor C2, C3, resistance R 2-R4, R6 forms, the relation of joining that connects of foregoing circuit is: an end of resistance R 1 connects the A point, capacitor C2, one end of resistance R 2 and 2 pin of NAND gate U2, the other end of resistance R 1 and B point, the input of capacitor C1 one end and not gate U1 joins, the other end ground connection of capacitor C1,1 pin of the output of not gate U1 and NAND gate U2 joins, 3 pin of NAND gate U2 and 2 pin of NAND gate U5 join, the output of the 1 pin NAND gate U6 of NAND gate U5 and 1 pin of NAND gate U7, the F point joins, 3 pin of NAND gate U5 and the end of capacitor C3 join, input and resistance R 6 one ends of the other end NAND gate U6 of capacitor C3 join, resistance R 6 other end ground connection, capacitor C2, one end of the other end of resistance R 2 and resistance R 3 and 2 pin of NAND gate U3 join, one end of the other end of resistance R 3 and resistance R 4 connects power supply jointly, 1 pin of the other end of resistance R 4 and NAND gate U3 joins, the input of the 3 pin NAND gate U4 of NAND gate U3 links to each other, 2 pin of the output of not gate U4 and E point and NAND gate U7 join, the input of the 3 pin NAND gate U8 of NAND gate U7 joins, the output termination G point of not gate U8.

3. electronic zero cut-in and cut-off contactor according to claim 1, the heavy-current control loop that it is characterized in that it is three-phase heavy-current control loop, wherein three-phase stable state place in circuit is made up of photoelectrical coupler U13, bidirectional thyristor U14, resistance R 13-R15, capacitor C6 and three-phase contactor JS3, three-phase transient state place in circuit, the importation of photoelectrical coupler U15, U17, U19 is connected into series connection, output is divided into three independent links, and each link is three groups of contact JA, JB, the JC of corresponding three-phase contactor respectively.