CN105656058A - Dynamic switching circuit of electromechanical synchronous switch of capacitor and control method of dynamic switching circuit - Google Patents

Abstract

The invention relates to an electromechanical synchronous switching technique of a capacitor, in particular to a circuit capable of achieving dynamic switching of an electromechanical synchronous switch and a control method of the circuit. The dynamic switching circuit of the electromechanical synchronous switch of the capacitor comprises the electromechanical synchronous switch arranged between a power grid and the capacitor, sampling circuits used for tracking voltage waveform changes of the two ends of the electromechanical synchronous switch respectively and a signal processing module arranged between a controller and the ends; the two ends are directly connected with the signal processing module separately, and the controller is used for receiving a switch-on or switch-off instruction of an upper computer and further connected with the trigger driving circuit end of the electromechanical synchronous switch. Accordingly, the switching response lag problem existing in the prior art is solved, and continuous dynamic switching is achieved.

Description

The dynamo-electric synchro-switch of electrical condenser is dynamically thrown and is cut circuit and control method thereof

Technical field

The present invention relates to electrical condenser electromechanics and synchronously throw incision technology, specifically a kind of electromechanics synchro-switch that realizes dynamically throws the circuit cut and control method thereof.

Background technology

It is known that, electrical network changes wattless power by changing the capacity of condenser in parallel, it it is the method for the most basic economical and effective with being generally used of current reactive-load compensation, low-voltage reactive compensator capable (refers to and realizes improving utilization of power efficiency by improving Power Factor of Distribution Network, reduce grid loss, promote the equipment of the function such as quality of power supply) in topmost element be exactly that electrical condenser and capacitor switching switch (refer in reactive-load compensation device, switching device for switched capacitor), and the performance of capacitor switching switch directly has influence on work-ing life and the compensation effect of electrical condenser, so its performance is most important.

Electrical condenser is a capacitive load, when it drops into or cuts out electrical network, will produce the transient process of a transient state. When condenser in parallel drops into electrical network, the surge current that amplitude is very big, frequency is very high can be produced, the melting welding phenomenon of performer contact also can occur when situation is serious. Operation superpotential can be produced when being excised from electrical network by condenser in parallel, cause the phenomenon of restriking of electric arc in power element breaking course. Existing capacitor switching switch mainly comprises alternating current contactor, thyristor switch, combination switch and dynamo-electric synchro-switch.

Alternating current contactor: being applied to secondary capacitor at first, to throw the switch cut be alternating current contactor, this is a kind of traditional capacitor switching mode, owing to the phase place of three-phase alternating current is mutually 120 ��, alternating current contactor is thrown and cuts control, there is not optimum operation phase point (namely throw and cut instantaneous Non-selectivity) in theory, its is made to drop into or during excision electrical network, the transient process of a transient state will be produced, again because electrical condenser is that voltage can not the device of transition. Condenser in parallel is thrown by alternating current contactor when cutting electrical network, owing to its electric current and voltage phase point is random: produce to shove (when shoving maximum may more than 100 times of electrical condenser rated current) during input, shove very easily burnt contact, and during excision, overvoltage electric arc of restriking burns out device. Shove and not only electrical network can be produced disadvantageous interference with overvoltage, but also the inefficacy of speed-up capacitor device, reduce the work-ing life of electrical condenser, even explode, so the switching mode harmonic pollution adopting alternating current contactor is big, maintenance cost height, be unsuitable for frequent operation and dynamically throw cutting.

Thyristor switch (solid state relay) and combination switch, both all have employed the switching element of silicon controlled rectifier as core. Owing to the triggering times of silicon controlled rectifier does not limit, it is possible to realizing Quasi dynamic and compensate (time of response is at Millisecond), the frequent throwing being therefore applicable to electrical condenser is cut, and is applicable to the load situation of frequent variations, has had the lifting of matter relative to alternating current contactor. But the shortcoming of silicon-controlled switch (SCS) be complex structure, volume is big, loss is big (for the compensation system of rated capacity 100Kvar, every phase rated current is about 145A, then the specified conduction loss of silicon controlled rectifier is 145 �� 1 �� 3=435W), conducting high power consumption determines that heat-dissipating space cost and cooling cost significantly increase, thyristor self unit cost is also higher.

Combination switch is that silicon controlled rectifier is in parallel with magnetic latching relay, to silicon-controlled zero current lead-through and the control turning off time point, avoids the generation of surge current. The switching of rly., all carries out when silicon controlled rectifier works, the switching under zero voltage of two ends, contact, avoids on contact the spark produced. Though combination switch solves high power consumption three significant deficiency of surge current, contact spark and electro-magnet line bag that contactor mechanical characteristics causes. But still surge current when there is silicon control zero-cross control skew or failure, operation overvoltage or thunderbolt, moment overheated etc. cause its susceptibility puncture (even demolishing) etc. problem cause reliability decrease.

Synchro-switch (has another name called phase-selecting switch) and is the technology of recent development in recent years, as the term suggests, make the contact of machinery switch accurately closed in the moment needed or disconnect exactly. For the synchro-switch performing switched capacitor, to be closed in the moment that switch contact both end voltage is zero exactly, thus the no-flashy-flow realizing electrical condenser drops into, disconnect in the moment that electric current is zero, thus it is disconnected to realize dividing without electric arc of switch contact, this whole process is referred to as operating passing zero.

Synchro-switch, compared with conventional thyristor switch, combination switch, eliminates silicon controlled component, so structure simplifies, volume reduces, and cost reduces. Existing synchro-switch patented technology, one as disclosed in Chinese patent CN20214286 is the liquid crystals combined power capacitor of apotype low-voltage intelligent altogether, it passes through current transformer, strong current is changed into the light current pressure signal proportional with electric current, by voltage transformer, high-voltage is changed into light current pressure signal; Electric current signal, voltage signal after conversion send into signal treatment circuit, after analog passband signal is crossed voltage-frequency conversion, frequency signal is input to MCU unit, MCU judges whether to need input compensation electric capacity simultaneously, or cut-out power capacitor, synchronous fling-cut switch is driven finally by driving circuit, realize operating passing zero, avoid the heavy current impact to electrical network, extend the contact life-span of fling-cut switch.

Specific implementation principle (schematic circuit diagram are shown in Fig. 1) is: when MCU unit inspection exceedes the value of setting to wattless power through time delay, to drop into A phase electric capacity, first detect voltage over zero, after voltage zero point being detected, time delay certain time (the time delay time is the semi-period of voltage waveform and the difference of the closed action time of synchro-switch), synchro-switch requires to be less than 5ms opening time, guarantee that electrical condenser drops into when voltage zero-cross like this, realize electrical network non-impact current is accessed power capacitor, during excision electric capacity, first detect A phase current and cross zero point, after current zero being detected, the time delay certain time difference of disconnection opening time of semi-period of voltage waveform and synchro-switch (the time delay time be), synchro-switch requires to be less than 5ms opening time, guarantee that electrical condenser excises when current over-zero like this, avoid phenomenon of arc discharge.

But also there is following technological deficiency in above-mentioned patented technology:

Before throwing is cut, electrical condenser has three kinds of possible states altogether, the first is be energized first (electrical condenser is always incomplete by charging or electric discharge already), 2nd kind is in energising (voltage on electrical condenser with electrical network voltage synchronously change), the third is that (electrical condenser is in discharge condition in firm power-off, if grid voltage waveform is in negative half cycle before power-off, electrical condenser is in be born to discharge condition; Positive half cycle is also with reason);

The quick throwing that technology disclosed in CN20214286 only can realize first and second kind of state is cut, and for the third state, phase-selecting switch (for avoiding generation to shove) must wait that electrical condenser fully discharges after completely, just can carry out zero passage input; Measuring according to reality, above-mentioned waiting time can at about 2min so that it is delayed that response is cut in synchro-switch throwing, and the dynamic throwing that cannot complete to continue is cut. Synchro-switch can only be finally a kind of static fling-cut switch.

Summary of the invention

Technical problem to be solved by this invention be to provide a kind of overcome to throw under the third state cut the delayed defect of response, it is achieved continue dynamically to throw the synchro-switch cut and dynamically throw and cut circuit and control method thereof.

In order to solve the problems of the technologies described above, the present invention provides following technical scheme:

The dynamo-electric synchro-switch of electrical condenser is dynamically thrown and is cut circuit, comprise the dynamo-electric synchro-switch between electrical network and electrical condenser, wherein, the sampling circuit for following the tracks of the voltage wave deformation separately of dynamo-electric synchro-switch two ends is also comprised, the signal processing module being located between controller and described end points;

Two end points are direct-connected with signal processing module separately, controller for accepting input or the excision instruction of upper computer, and controller also triggering driving circuit end with dynamo-electric synchro-switch be connected.

The dynamo-electric dynamic switching control method of synchro-switch of electrical condenser, comprises the steps,

A. the dynamo-electric synchro-switch two ends of controller detection voltage change separately, follows the tracks of respectively and is labeled as grid voltage waveform and condenser voltage waveform, and calculate the function U-t expression formula of two waveforms respectively;

B. controller waits input or the excision instruction of upper computer;

C. controller receives and drops into or after excision instruction, through t2 certain time of lag, send corresponding triggering signal to dynamo-electric synchro-switch; Wherein the calculating formula of t2 is

T1-t3 is when condenser voltage perseverance is zero;

T2=t4-t3 is when condenser voltage is cosine waveform;

T5-t3 when condenser voltage exponentially waveform time.

Wherein t1 represents to receive by controller and drops into when instruction crosses zero point to grid voltage waveform required time;

T3 represent dynamo-electric synchro-switch performer by receive trigger actuate signal to complete to excise or input operate required for time;

T4 represents the time receiving by controller and excising instruction and become required when reaching crest or trough to grid voltage waveform;

T5 represents to receive by controller and drops into when instruction crosses to electrical network voltage and capacitor discharge voltage required time;

Solving of above-mentioned calculating formula, premised on t2 >=0, tries to achieve the minimum value of t2;

D. step b is returned to.

Compared with prior art the technical program has following useful effect:

1, condenser voltage perseverance is zero, and what now controller received can only be drop into instruction, and this belongs to prior art, does not repeat herein;

2, condenser voltage is cosine waveform, and namely condenser voltage is followed electrical network voltage and synchronously changed, and electrical condenser is in access switch-on regime, and the switch command that now controller receives can only be excision instruction. In order to not produce electric arc when ensureing excision, should for excising during zero current between electrical network and electrical condenser. Characteristic according to electrical condenser, when electrical condenser is zero current, condenser voltage is just the state of crest or trough. Also just based on this thinking, the throwing of the present invention is cut and is not arranged electric current, voltage transformer in circuit, it is only that electromechanics synchro-switch two ends current potential is connected with controller by signal processing module (step-down or analog to digital conversion), like this can be cost-saving further, save space.

3, condenser voltage exponentially waveform, namely electrical condenser is in discharge condition, and electrical network circuit has interrupted the power supply to electrical condenser, and the switch command that now controller receives can only be drop into instruction.

In order to make not produce to shove during input, and not waiting that electrical condenser discharges completely, the present invention gathers separately condenser voltage and grid voltage waveform; Before dropping into, both are independent of each other by voltage, when condenser voltage and electrical network voltage waveform cross, drop into when namely electromotive force is equal, it is ensured that the voltage being carried on dynamo-electric synchro-switch during input is zero; Complete input operation. Although capacitor discharge needs completely > 2min, but in an electrical network voltage cycle (20ms), the inherently requirement of a time point satisfied " condenser voltage and electrical network voltage cross ", so just achieving dynamically dropping into fast of ms level.

Accompanying drawing explanation

Fig. 1 is schematic circuit diagram of the prior art.

In figure, arrow expression signal flows to.

Embodiment

Below in conjunction with drawings and Examples, technical solution of the present invention is illustrated further:

The dynamo-electric synchro-switch of electrical condenser is dynamically thrown and is cut circuit as shown in Figure 1, comprise the dynamo-electric synchro-switch between electrical network and electrical condenser, wherein, the sampling circuit for following the tracks of the voltage wave deformation separately of dynamo-electric synchro-switch two-end-point is also comprised, the signal processing module being located between controller and described end points;

Two end points are direct-connected with signal processing module separately, controller for accepting input or the excision instruction of upper computer, and controller also triggering driving circuit end with dynamo-electric synchro-switch be connected.

Described signal processing module can be the merge module of controller can also be peripheral module; It mainly acts on is overvoltage protection and analog to digital conversion.

The dynamo-electric dynamic switching control method of synchro-switch of electrical condenser, comprises the steps,

A. the dynamo-electric synchro-switch two ends of controller detection voltage change separately, follows the tracks of respectively and is labeled as grid voltage waveform and condenser voltage waveform, and calculate the function U-t expression formula of two waveforms respectively;

B. controller waits input or the excision instruction of upper computer;

C. controller receives and drops into or after excision instruction, through t2 certain time of lag, send corresponding triggering signal to dynamo-electric synchro-switch; Wherein the calculating formula of t2 is

T1-t3, when condenser voltage perseverance is zero;

T2=t4-t3, when condenser voltage is cosine waveform;

T5-t3, condenser voltage exponentially waveform time.

Wherein t1 represents to receive by controller and drops into when instruction crosses zero point to grid voltage waveform required time;

T3 represent dynamo-electric synchro-switch performer by receive trigger actuate signal to complete to excise or input operate required for time;

T4 represents the time receiving by controller and excising instruction and become required when reaching crest or trough to grid voltage waveform;

T5 represents to receive by controller and drops into when instruction crosses to electrical network voltage and capacitor discharge voltage required time;

Solving of above-mentioned calculating formula, premised on t2 >=0, tries to achieve the minimum value of t2;

D. step b is returned to.

The length of t3 depends primarily on dynamo-electric synchro-switch, it is possible to determine according to producing to arrange, it is also possible to input is applied front direct-detection and determined.

Execution module is cut in throwing, and namely dynamo-electric synchro-switch adopts sea salt magnetic latching relay HZX-301FA;

Computing, signal acquisition module (set sampling circuit and MCU), choose the STC12C5616AD of grand brilliant science and technology;

Power supply module adopts the T3L-04 in wound four directions, Beijing; Being provided with throwing between MCU and upper computer and cut signal receiving module, this module adopts the PC817 of Sharp.

Above-described is only embodiments of the invention, in scheme, the general knowledge such as known concrete structure and characteristic does not do too much description at this, one skilled in the art know the applying date or priority date before all ordinary technical knowledge of technical field that the present invention belongs to, prior aries all in this field can be known, and the ability of normal experiment means before there is this date of application, under the enlightenment that one skilled in the art can provide in the application, improve in conjunction with self-ability and implement this scheme, some typical known features or known method should not become the obstacle that one skilled in the art implement the application. should be understood that, for a person skilled in the art, under the prerequisite not departing from present configuration, some distortion and improvement can also be made, such as the dynamo-electric synchro-switch that dynamo-electric synchro-switch selects voltage-phase synchronous, to dynamo-electric synchro-switch input free voltage signal, the phase place of the voltage signal exported all does not change, namely the phase place of voltage signal is not done any change by dynamo-electric synchro-switch, and the dynamo-electric synchro-switch with this kind of performance is comparatively applicable to the present invention. these also should be considered as protection scope of the present invention, and these all can not affect effect of the invention process and practical applicability. the protection domain that this application claims should be as the criterion with the content of its claim, and the embodiment in specification sheets etc. record the content that may be used for explaining claim.

Claims (2)

1. the dynamo-electric synchro-switch of electrical condenser is dynamically thrown and is cut circuit, comprise the dynamo-electric synchro-switch between electrical network and electrical condenser, it is characterized in that, also comprise the sampling circuit for following the tracks of the voltage wave deformation separately of dynamo-electric synchro-switch two ends, the signal processing module being located between controller and described end points;

Two end points are direct-connected with signal processing module separately, controller for accepting input or the excision instruction of upper computer, and controller also triggering driving circuit end with dynamo-electric synchro-switch be connected.

2. the dynamo-electric dynamic switching control method of synchro-switch of electrical condenser, it is characterised in that, comprise the steps,

A. the dynamo-electric synchro-switch two ends of controller detection voltage change separately, follows the tracks of respectively and is labeled as grid voltage waveform and condenser voltage waveform, and calculate the function U-t expression formula of two waveforms respectively;

B. controller waits input or the excision instruction of upper computer;

C. controller receives and drops into or after excision instruction, through t2 certain time of lag, send corresponding triggering signal to dynamo-electric synchro-switch; Wherein the calculating formula of t2 is

T1-t3 is when condenser voltage perseverance is zero;

T2=t4-t3 is when condenser voltage is cosine waveform;

T5-t3 when condenser voltage exponentially waveform time;

Wherein t1 represents to receive by controller and drops into when instruction crosses zero point to grid voltage waveform required time;

T3 represent dynamo-electric synchro-switch performer by receive trigger actuate signal to complete to excise or input operate required for time;

T4 represents the time receiving by controller and excising instruction and become required when reaching crest or trough to grid voltage waveform;

T5 represents to receive by controller and drops into when instruction crosses to electrical network voltage and capacitor discharge voltage required time;

Solving of above-mentioned calculating formula, premised on t2 >=0, tries to achieve the minimum value of t2;

D. step b is returned to.