CN106356871A - Static var compensator - Google Patents

Abstract

The invention discloses a static var compensator. A DSP (digital signal processor) based control system selects a TMS320F2812DSP chip as a core control device and comprises a signal detection circuit, a frequency measurement circuit, a synchronous signal detection circuit, a trigger circuit, a general I/O (input/output) port circuit, an SCI (serial communication interface) circuit and a power supply circuit to form a basic control system of the static var compensator. Controller hardware mainly comprises a signal acquiring and conditioning module, a frequency measuring module, a synchronous signal detection module, a control execution module, a thyristor trigger module, a power supply module, an I/O and SCI module and the like and designed on the basis of a DSP system. The SVC (static var compensator) with the DSP-based control system can be used for regulating voltage to increase steady transmission capacity, improve transient stability, enhance damping of an electric system, relieve sub-synchronous resonance, prevent voltage instability and improve performances of a direct-current power transmission system.

Description

A kind of static passive compensation device

Technical field

The present invention relates to a kind of inactivity compensation device, more particularly, to a kind of static reacance rate compensation device.

Background technology

The developing rapidly of Chinese national economy, electrical network scale gradually expands, industrial arc, rolling mill, electric locomotive etc. Impact load is widely used in industrial application, and it is low that these loads have a power factor, and idle change is greatly and drastically Feature, the rapid fluctuation of low-voltage network voltage can be caused during operation so that the quality of power supply deteriorate, a large amount of line losses with Generation, and substantial amounts of higher hamonic wave can be injected toward in system, have a strong impact on the quality of power supply of system power supply, and can be not Have influence on the normal work of user with degree.

SVC (svc) is one kind of custom power technology, is grow up early 1970s new Technology." static " is for the synchronous capacitor of rotation, domestic be called dynamic reactive compensator, this is for solid For determining capacitance group (fixed capacitor, fc).Svc is by controlling the angle of flow of IGCT in parallel come quick regulation The size of reactor or switched capacitor group.The most basic two types structure of svc is Thyristor Controlled Reactor type (thyristor phase controlled reactor, tcr) and thyristor switchable capacitor type (thyristor Switched capacitor, tsc).Tcr and tsc can form tcr+tsc, or forms tcr+fc and tcr+tsc+ with fc The hybrid architectures such as fc, adopt tcr+fc type for load compensation is most.

, due to not having rotary part, maintenance requirement is relatively low for SVC, and control response is quick, can be by phased System, loss is little, and reliability is high, does not affect system short circuit capacity.But in addition to thyristor switchable capacitor (tsc), svc can produce Harmonic wave, when outside svc operating in linear controlled range, the reactive power that it sends changes with the quadratic power of terminal voltage, causes The weakening significantly of reactive power support during low-voltage.

Static reactive power compensation device is to adjusting load power factor, stable and balance system voltage, eliminate and flow to system Higher harmonic current, balance three-phase load etc. have obvious action.It is installed in high voltage power transmisson system and can be used for controlling The dynamic overvoltage of the heroic spirits such as long distance transmission line removal of load, unloaded effect, improves the steady-state stability of system, suppression system Reactive power and voltage oscillation.

Content of the invention

It is an object of the invention to provide one kind can reduce place capacity, reduce power attenuation, stablize line voltage, improve Power quality, can also balance the SVC of three phases active power and reactive power by suitable control.

The present invention employs the following technical solutions realization, a kind of static reacance power device, the control system based on dsp System, is kernel control chip from tms320f2812dsp chip, also include signals collecting and modulate circuit, frequency measurement circuit, every From amplifying circuit, telecommunication circuit, i/o interface circuit, Key and display circuit, constitute a basic static reactive dress The control system put.Controller is provided with capturing unit, receives frequency measurement circuit.Adcin interface on controller connects signal and adopts Collection and modulate circuit.General io port is additionally provided with controller, and io interface circuit connects, and io interface circuit and keyboard with aobvious Show that circuit connects.Sci interface on controller is connected with telecommunication circuit.Pwm on controller and isolating amplifier circuit connect, and Isolating amplifier circuit connects tcr thyristor controlled series compensation.Controller is also connected with real-time clock.

Controller system is mainly used in whole system being controlled, coordinate and protecting.Most important part therein is control The hardware configuration of device processed, controller hardware mainly includes signals collecting and conditioning module, frequency measurement module, synchronization signal detection mould Block, control performing module, IGBT group module, power module, i/o and sci port module etc..Hardware is based on dsp system Design.Control circuit needs collection from the output of pt, ct, and collection capacity becomes light current through overvoltage, current transformer Signal, then signal is nursed one's health, the adc interface of input dsp, algorithm is executed by dsp, after time delay inputs trigger pulse to crystalline substance Brake tube triggers circuit, pulse amplifies triggering IGCT through isolation.

The control system based on dsp that the present invention provides, the svc that it is constituted can be used for adjusting voltage, improves stable state conveying Capacity, the damping improving transient stability, strengthening power system, alleviation subsynchronous resonance, prevention spread of voltage and improvement are straight The performance of stream transmission system.

Brief description

Fig. 1 is the control system theory diagram of the present invention.

Fig. 2 is the svc total system composition schematic diagram of the present invention.

Fig. 3 is the structure of thyristor controlled series compensation.

Fig. 4 is tms320f2812.

Fig. 5 sample circuit schematic diagram.

Fig. 6 is signal conditioning circuit.

Fig. 7 is optocoupler type sine wave-square wave translation circuit.

Fig. 8 is optocoupler input-output wave shape figure.

Fig. 9 forms circuit for synchronizing signal.

Figure 10 forms circuit theory frame for trigger pulse.

Figure 11 is stretch circuit.

Figure 12 is pulse stretching oscillogram.

Figure 13 is three output winding transformer triggers circuits of IGCT.

Figure 14 is light electro-optical circuits schematic diagram.

Figure 15 is telecommunication circuit.

Figure 16 is liquid crystal display circuit.

Figure 17 is keyboard circuit.

Figure 18 is real time clock circuit.

Figure 19 is D.C. regulated power supply structure chart and voltage stabilizing procedure chart.

Figure 20 is voltage source circuit.

Specific embodiment

Fc+tcr type svc main loop figure

As Fig. 1, in the main circuit diagram of fc+tcr type svc electric power system, systematic parameter: load (ac arc furnace and ladle Stove) busbar voltage: 10kv；Pt: voltage ratio 10000v/100v；Ct: electric current compares 1000a/5a.

In figure is to illustrate, and in high-pressure thyristor valve group, single-phase depicts a pair of anti-parallel thyristor, and fc filter is only Depict four branch roads.Whole fc+tcr type svc device can be divided into four parts, the structure of various pieces and work(according to function Can be described below:

(1) fc wave filter: the single or multiple filtering channels being made up of reactor, power capacitor, it is respectively used to filter Corresponding higher hamonic wave, also provides the effect of certain capacitive reactive power simultaneously to system.

(2) compensation reactor: hollow dry-type selected by compensation reactor, upper and lower twin coil, the natural type of cooling and can Resistance to rush of current.Principle be triggering high-pressure thyristor after produce electric current flow through compensation reactor, the sense required for generation system Property idle, balance system reactive power, also act as simultaneously stable busbar voltage and adjustment power factor effect.

(3) high-pressure thyristor valve group: high-pressure thyristor valve group accepts the trigger from numerical control system, by changing Become the size of IGCT Trigger Angle, so that reactor produces corresponding reactive-load compensation electric current.

(4) numerical control system: numerical control system is used for Real-time Collection voltage signal, current signal, calculates on bus Reactive power and admittance value to be compensated, control the size of IGBT group delay angle, send trigger pulse, and then realize changing no The purpose of the size of work(power.

The parameter of tcr calculates

The cancellation ratio of svc is

C=100% q_svc/δq_max(3-1)

In formula: q_svcDynamic compensation capacity for svc, the rated capacity of mvar, also referred to as svc；δq_maxFor wavy load Maximum reactive power amount of change, mvar.

Because the fc+tcr type svc device of the present invention is for Electric Furnace Design, idle change ratio when electric arc furnace puts into operation Relatively violent, consider further that the purpose installing svc additional is to compensate the reactive power producing when electric arc furnace runs, can be by the compensation of svc Rate elects 1 as.

For realizing the dynamic compensation capacity q of svc_svc, theoretical rated capacity q of tcr reactor need to be increased_l.

Because having

q_svc=q_l·(2π-2α_min+sin 2α)/π (3-2)

In formula: α_minFor the minimum pilot angle of high-pressure thyristor valve group, rad.

Then the inductance ratings of reactor are

$l_e=\frac{3\×u_e^2}{{\mathrm{\ωq}}_{svc}}\·\frac{2\mathrm{\π}-2{\mathrm{\α}}_{\min }+sin2{\mathrm{\α}}_{\min }}{\mathrm{\π}}---(3-3)$

In formula: u_eRated voltage for reactor；ω is power supply angular frequency.

The rated current of tcr is

$i_{le}=\frac{u_e}{{\mathrm{\ωl}}_e}\·\frac{2\mathrm{\π}-2{\mathrm{\α}}_{min}+sin2{\mathrm{\α}}_{min}}{\mathrm{\π}}---(3-4)$

This factory's maximum reactive power variable quantity known is δ q for 24mvar_max=24mvar.

As cancellation ratio c=100%, the dynamic compensation capacity q of svc_svc=c δ q_msx=24mvar.

If the minimum pilot angle of tcr is α_min=105 °=1.832596rad, then the inductance ratings of reactor can by (3-3) ?

The rated current of reactor can be obtained by (3-4)

Select IGCT according to this, its on-state average current is 1.5 2 times of this result.

The parameter of wave filter calculates and designs

The index of utility network harmonic wave

Higher harmonic current is that nonlinear-load produces, in alternating current arc, create 2 due to arc current distortion, 3rd, 4 and 7 inferior harmonic wave.According to the requirement of gb/t14549-93 " quality of power supply utility network harmonic wave ", harmonic wave causes line voltage Irregularity of wave form is not to be exceeded the ultimate value of the exterior and the interior, and the harmonic current that user injects electrical network is not to be exceeded the permission listed by the exterior and the interior Value.

Table 1 utility network harmonic voltage (phase voltage) ultimate value

Table 2 injects the public allowable harmonic current of utility network

In the present invention, busbar voltage is 10kv it is known that system minimum capacity of short circuit is 220mvar, is released actual by following formula The minimum capacity of short circuit of operating mode standard allows harmonic current value, charges to table 3-3.

$i_n=\frac{s_{n1}}{s_{n2}}\·i_{np}---(3-5)$

In formula: s_n1Minimum capacity of short circuit for common junction

s_n2On the basis of capacity of short circuit

i_npFor allowable harmonic current

The allowable harmonic current of points of common connection is injected under the minimum capacity of short circuit of table 3

The determination of wave filter

(1) calculate the fundamental wave reactive power capacity of fc

According to actual situation, svc generally requires the capacitive range of accommodation with 0～100%, then fixed filters group Fundamental wave reactive power capacity can be obtained by following formula:

q_fc1=q_svc[1-(2π-2α_max+sin2α_max)/π] (3-6)

In formula: α_maxFor the maximum pilot angle of high-pressure thyristor valve group, rad.

If maximum controlling angled a_maxDuring=165 °=2.879793rad, and q_svc=24mvar, fixing filtering as available from the above equation Device group fundamental wave reactive power capacity is:

q_fc1=24 × [1- [2 π -2 × 2.879793+sin (2 × 165 °)]/π]=23.82m var

(2) calculate the harmonic current of each harmonic branch road

Calculate the harmonic current flowing through each filter branch, individual harmonic current content will be surveyed, with reference to injection public power The standard of net harmonic wave, also will consult to increase the individual harmonic current value that can remain in system after wave filter with user.This factory is humorous The main harmonic wave of ripple content is 2,3,4,5 subharmonic content overproofs.2,3,4,5 single tuned filters of this paper design and installation, really In system after Dingan County's dress wave filter, the harmonic current residue of each time is respectively smaller than the value in table 3-3.

The harmonic current value of each filter branch should consider tcr generation harmonic current, can adjust respectively for:

i₂=10.58a, i₃=20.2a, i₄=21.5a, i₅=37.5a

(3) calculate the fundamental wave capacity of each harmonic branch road harmonic filter

The fundamental wave capacity of each filter branch should calculate according to harmonic current distribution method, the svc compensation capacity needed for this factory For 24mvar, then the fundamental wave capacity of each harmonic wave filter can determine according to the following formula.

$q_{1n}=\frac{i_n/n}{\underset{n=2}{\overset{\mathrm{\∞}}{\σ}}(i_n/n)}\·q_{svc}---(3-7)$

Can obtain:

q_2n=5.10mvar, q_3n=6.49mvar, q_4n=5.18mvar, q_5n=7.23mvar

(4) calculate the capacitance of each filter branch harmonic filter

In engineering design, the capacitance c of single tuned filter_nCan be calculated by following formula and try to achieve:

$q_{\mathrm{in}}=u_1^2\·\mathrm{\ω}\·c_n---(3-8)$

In formula: q_inFor each harmonic wave filter fundamental wave capacity (mvar)

u₁For fundamental wave rated line voltage (kv)

c_nFor each harmonic filter capacitance (f)

By u₁=10kv brings into, can obtain:

c₂=162.34 μ f, c₃=206.58 μ f, c₄=164.88 μ f, c₅=230.14 μ f

(5) calculate each filter branch harmonic filter load voltage value

In the design of each branch filter, in order to ensure wave filter can safe and reliable operation, must calculate The rated operational voltage of wave filter.

The harmonic voltage of each filter branch can be tried to achieve by following formula it may be assumed that

u_cn=i_cn/(nω·c_n) (3-9)

Then the rated voltage of each filter branch is:

u_ce=u₁+u_cn(3-10)

Data is substituted into, can obtain:

u_ce2=10103.72v, u_ce3=10103.75v, u_ce4=10103.77v, u_ce5=10103.73v

(6) calculate the installed capacity of each filter branch harmonic filter

According to two formula above, the rated capacity of wave filter can be tried to achieve, that is, installed capacity is:

$q_{ce}=u_{ce}^2\·\mathrm{\ω}\·c_n---(3-11)$

Substitute into data, can obtain:

q_ce2=5.21mvar, q_ce3=6.63mvar, q_ce4=5.29mvar, q_ce5=7.38mvar

(7) calculate the inductance value of each filter branch series reactor

Relation according to electric capacity during filter branch resonance and inductance

${\mathrm{nx}}_l=n\mathrm{\ω}l=\frac{1}{n\mathrm{\ω}c}=\frac{x_c}{n}---(3-12)$

Have

$l_n=\frac{x_c}{n\mathrm{\ω}}=\frac{1}{{\mathrm{n\ωc}}_n}\·\frac{1}{n\mathrm{\ω}}=\frac{1}{n^2{\mathrm{\ω}}^2{c}_n}---(3-13)$

For 2 subharmonic: 2x_l=x_c/ 2, then x_l=x_c/ 4=0.25x_c, each load compensation and transformer station commonly used return In road, the reactance of series connection 26% constitutes 2 subharmonic wave filter, so, x_l=0.26x_c, then

$l_2=\frac{0.26}{{\mathrm{\ω}}^2{c}_2}=16.23mh;$

In the same manner,

For 3 subharmonic: 3x_l=x_c/ 3, then x_l=x_c/ 9=0.11x_c, take 0.12 times, then

$l_3=\frac{0.12}{{\mathrm{\ω}}^2{c}_3}=5.89mh;$

For 4 subharmonic: 4x_l=x_c/ 4, then x_l=x_c/ 16=0.06x_c, take 0.08 times, then

$l_4=\frac{0.08}{{\mathrm{\ω}}^2{c}_4}=4.92mh;$

For 5 subharmonic: 5x_l=x_c/ 5, then x_l=x_c/ 25=0.04x_c, take 0.06 times, then

$l_5=\frac{0.06}{{\mathrm{\ω}}^2{c}_5}=2.64mh.$

(9) calculate the resistance of current-limiting reactor

$r=\frac{x_n}{q}=\frac{1}{q}\sqrt{\frac{l}{c}}---(3-14)$

In formula: x_nFor the feature reactance of wave filter, q is the quality factor of filter reactor.Quality factor are mainly used to examine Examine filter effect although being the bigger the better in theory, but if quality factor are excessive, system is easier off resonance, therefore typically in list In tuning filtering device, take 30～60.In this secondary design, filter reactor q is 30.

Then substitute into data can obtain: r₂=0.75 ω, r₃=0.40 ω, r₄=0.41 ω, r₅=0.25 ω

Main parameter calculation value according to being calculated each wave filter above is as follows:

Table 4 single tuned filter parameter list

The parameter of thyristor controlled series compensation calculates and design

The basic structure of thyristor controlled series compensation

Thyristor controlled series compensation is the control target of svc control system.IGCT is limited by voltage x current rated value, needs Series connection or (and) used in parallel.Because medium and small user's compensation capacity of 10kv electric pressure is all less big, the electricity of IGCT in addition Stream rated value, up to upper kiloampere, so being rarely employed parallel connection, only considers series connection.The characteristic dispersion of IGCT is it is impossible to simple go here and there Connection uses, and need to be solved using technology of pressure equalization.The most popular method of steady-state pressure is to each series thyristor parallel connection one Equalizing resistance is it is desirable to the electric current in equalizing resistance is more than the leakage current of IGCT.Open and reversely close because IGCT exists again The difference of disconnected recovery time, occurs that the voltage distribution of transient state is uneven during this period, also needs all to press measure using transient state, method it One is in the two ends of every IGCT parallel connection resistance capaciting absorpting circuit, absorbs transient overvoltage simultaneously.In actual svc device, Thyristor controlled series compensation does not adopt antiparallel mode of first connecting again, but forms by the way of first inverse parallel is connected again.Do so There are two benefits: one is not affect valve group work after some IGCT damages；Two to be that forward and reverse IGCT can share a set of Stable state and transient state equalizer circuit.The structure of thyristor controlled series compensation such as Fig. 3-4.Resistance r_pFor steady-state pressure resistance, r_b、c_bFor playing transient state The resistance-capacitance absorption loop that all pressure acts on.

The parameter of thyristor controlled series compensation calculates

(1) thyristor controlled series compensation devices in series number calculates

Thyristor controlled series compensation devices in series number determines as the following formula

n_s=u_amk_cuk_bk_au/(u_rmk_u) (3-15)

In formula: k_cuFor overvoltage impact coefficient, take 1.3～1.6；u_amFor the forward and reverse big value of the Peak Operating Voltage of arm, v；k_bFor line voltage step-up ratio, typically take 1.05～1.1；k_auFor the design margin of voltage, typically take 1～2, according to device Depending on reliability；k_uFor all pressing coefficient, take 0.8～0.9；u_rmFor IGCT specified repetitive peak voltage, v.

(2) steady-state pressure resistance parameter calculates

Steady-state pressure resistance parameter is calculated as follows

r_p≤(1/k_u-1)u_rm/i_rm(3-16)

In formula: u_rmFor IGCT specified repetitive peak voltage, v；i_rmFor corresponding IGCT specified repetitive peak voltage u_rm's Repetitive peak leakage current；k_uFor all pressing coefficient, take 0.8～0.9.

(3) parameter of resistance capaciting absorpting circuit calculates

Absorption Capacitance c_bThe value of (μ f) can be obtained by following formula:

In formula: δ q_maxFor the maximum difference of QRR between series thyristor, μ c；For line voltage peak Value, v；Remaining is ibid.

In order to preferably suppress the shutoff overvoltage of IGCT, resistance r_bResistance select to make the inductance of tcr reactor L, resistance-capacitance absorption equivalent capacity c '_b=c_b/n_sWith absorption equivalent resistance r '_b=n_sr_bThe series circuit constituting is in slight underdamping State.

(4) Selection and Design of IGCT

According to the compensation capacity 24mvar of tcr, the upper rated current crossed of each phase IGCT valve arm is 799.84a.So Select the IGCT of the 5stp12n8500 model of abb company, parameter is as shown in table 5 below.

Table 5 IGCT parameter

According to the number of system voltage and the pressure decision series connection of selected IGCT, over-pressed coefficient typically takes 3～4 times, brilliant The excessively stream coefficient of brake tube electric current typically takes 2～3 times.WhereinThyristor controlled series compensation device can be calculated by (3-15) Serial number calculates following table:

Table 6 thyristor controlled series compensation devices in series number

uam	kcu	kb	kau	ku	Thyristor controlled series compensation number
						14142v	1.3	1.05	1.1	0.9	3

R ' can be calculated by (3-16) and (3-17)_b=3 × r_b=1.5 ω,

The hardware designs of tcr control system

Tcr control system is summarized

Three major functions of one preferable reactive load compensation device are: by power factor bring up to 1 or close to 1st, the voltage stablizing compensation point is in acceptable scope, the three-phase voltage of balanced compensated point, electric current.

In order to realize different compensation targets, the control system of svc is also not quite similar, and mainly has following four form: open Ring control, closed loop control, complex controll and computer control system.

Computer control system based on dsp

Controller system is mainly used in whole system being controlled, coordinate and protecting.Most important part control therein The hardware configuration of device processed, controller hardware mainly includes signal acquisition module, frequency measurement module, synchronization signal detection module, control Performing module, IGBT group module, power module, i/o and sci port module etc..

The system measurement electrical network three-phase voltage, current signal, final goal is intended to produce tcr thyristor triggering impulse letter Number, its major function is as follows:

(1) carry out the measurement (including voltage, electric current and frequency) of three-phase alternating current point；

(2) compensate the mathematical model of susceptance and current sampling data according to three-phase, carry out the computing at thyristor control angle；

(3) output of thyristor triggering impulse.

Control system theory diagram such as Fig. 1, hardware is based on dsp system design.Control circuit need collection from pt, The output of ct, collection capacity becomes weak electric signal through overvoltage, current transformer, then signal is nursed one's health, input dsp's Adc interface, executes algorithm by dsp, inputs trigger pulse to thyristor gating circuit, pulse is amplified tactile through isolation after time delay Hair crystal brake tube.

Control core dsp

The tms320f2812 digital signal processor that the present invention is produced using TIX (it) is to be directed to Digital control design, incorporate the optkmal characteristics of dsp and microcontroller, be used primarily in embedded Control, such as digital motor control The fields such as system, data extraction and i/o control.For application optimization, and effectively shorten product development cycle, f28x core is supported The compiler of brand-new ccs environment, provides the program development interface being directly embedded into assembler language in c language.It has following main Function and feature:

(1) high-performance static state cmos makes technology

1. dominant frequency is up to 15omhz, and each clock cycle is 6.67ns；

2. adopt low voltage power supply, core voltage is 1.8v when dominant frequency is for 135mhz, the kernel when dominant frequency is for 150mhz Voltage is 1.9v, and i/o pin voltage is 3.3v.

(2) support jtag in-circuit emulation interface

(3) 32 high-performance processors

1. support the multiplication additive operation of 16b × 16b and 32b × 32b；

2. support the double multiplying of 16b × 16b；

3. adopt Harvard bus structures pattern；

4. quick interrupt response and interrupt handling capacity；

5. unified design Storage pattern；

6. compatible c/c++ language and assembler language.

(4) piece memory space

1. in piece, flash space size is 128k × 16b, is divided into 4 8k × 16 and 6 16k × 16 memory paragraphs；

2. rom space: piece includes the rom of 128k × 16b size；

3. otp rom space size: 1k × 16b；

4. l0 and li: two pieces of 4k × 16b single-address addressing random access memory (saram)；

5. h0: one piece of 8k × 16b saram；

6. m0 and m1: two pieces of 1k × 16b saram.

(5) boot rom space

Space size is 4k × 16b, includes software start-up mode and standard mathematical function storehouse.

(6) external interface

1. it is up to total memory space of im × 16b；

2. the programmable waiting time；

3. programmable read-write sequence；

4. three independent chip selection signals.

(7) clock and system control

1. support dynamic frequency multiplication of phase locked loop；

2. piece internal oscillator；

3. include house dog time block.

(8) three external interrupt

(9) peripheral interrupt module (pie) can support 45 peripheral interrupts

(10) 3 32 cpu intervalometers

(11) 128 safe keys

1. flash rom otp and l0 l1 saram can be comprised；

2. system hardware, software is prevented to be modified.

(12) it is used for the peripheral hardware of controlled motor

(13) two-way task manager (eva, evb)

(14) communication port

1. Serial Peripheral Interface (SPI) (spi)；

2. two-way serial communication interface (sci), standard uart mouth；

3. enhancement mode can module (ecan)；

4. multichannel buffer serial line interface (msbsp).

(15) 12 adc modular converters

1. 2 × 8 tunnel input channel；

2. two sampling and keep modules；

3. single or cascade change pattern；

4. highest conversion ratio is 80ns/12.5msps.

(16) 56 general gpio mouths

(17) advanced simulation model

1. there is the real-time function of analyzing and arrange breakpoint；

2. support simulation hardware.

(18) developing instrument

1. dsp the integration environment (ccs)；

2. jtag emulator.

(19) low power mode and power storage

1. support idle, standby, halt pattern；

2. prohibiting/enabling independent peripheral clock.

By data above as can be seen that tms320f2812 has powerful mathematical operational ability and control ability, hold very much Easily realize carrying out data processing and function control to whole system, its internal structure block diagram is as shown in Figure 4.

The operation principle of tms320f2812 is: its adc module collection three-phase voltage, electric current, cap module reception line voltage, Frequency signal, calculates the susceptance value of required compensation, is converted to tcr pilot angle, be converted to technology pulse according to phase-shift theory Number d, is stored in countdown depositor.After line voltage reaches time zero, delayed startup, afterwards toward each pwm pin The trigger pulse of output, as shown in table 7 below.

The each pin of table 7pwm and its function

Pin title	Function
		pwm1	uacPositive half cycle pulse output
pwm2	ubcPositive half cycle pulse output
		pwm3	ubaPositive half cycle pulse output
pwm4	uacNegative half period pulse exports
		pwm5	ubcNegative half period pulse exports
pwm6	ubaNegative half period pulse exports

The principle of phase-shifting trigger is that control Trigger Angle α is converted into corresponding time delay t_α, then it is converted to corresponding counting arteries and veins Rush number d.α is scaled t_αFormula be

$t_{\mathrm{\α}}=\frac{\mathrm{\α}}{360}t---(4-1)$

In formula, t is the cycle of thyristor alternating-current power supply.

Frequency as the timer of task manager is f_c, then with t_αCorresponding count pulse number is

$d=t_{\mathrm{\α}}{f}_c=\frac{\mathrm{\α}}{360}{\mathrm{tf}}_c---(4-2)$

Here it is dsp chip is transferred to the initial value of timer, counts after resetting, send trigger pulse.

Signal acquisition circuit

System voltage, electric current are converted to 100v voltage signal and 5a current signal by pt and ct, but 100v voltage can not It is directly entered numerical control system, so adding secondary transformer in front end.To be 0 from pt virtual value with voltage transformer The ac voltage signal of 100v becomes the ac voltage signal that virtual value is 0 3.53v, and Current Transformer will be effective from ct It is worth the ac current signal for 0 5a and becomes the ac voltage signal that virtual value is 0 3.53v, needed with being suitable for sample circuit Ask, and ensure the verity of signal.So both transformers will have sufficiently wide frequency response it is ensured that the amplitude of input signal Distortion is little, and phase place has linear phase characteristic, and signal is being electrically isolated with outside, improves capacity of resisting disturbance, protects Barrier personal safety.But the normal input voltage range of dsp analog/digital conversion kernel is 0～3.3v, otherwise dsp can be caused to damage. It is sent to modulate circuit through the low voltage signal of two-stage transformer conversion, after being changed into the electrode signal of 0～3.3v, directly Sampled by dsp chip.If Fig. 5 is the theory diagram of sample circuit.

The design selects the voltage transformer of Tianrui tr1102-1c, the current transformer of Tianrui tr0102-2c, main skill Art index is as shown in the table:

Table 8 measurement tr1102-1c voltage transformer parameter

Tr0102-2c current mutual-inductor parameter is used in table 9 measurement

The operation principle of Fig. 6 taking a phase voltage as a example signal Analysis Acquisition Circuit.In figure, input voltage signal u_aThrough electricity Resistance r₁And r₂Partial pressure after connect to first amplifier a₁, a₁Constitute emitter follower, input resistance and load energy can be increased Power.Through r₁And r₂Partial pressure effect have:

$u_a=\frac{r_2}{r_1+r_2}{u}_a^{\′}---(4-3)$

a₂Constitute inverse proportion amplifier, adjust r₅Amplification, electric capacity c can be changed₁The phase shift being used for compensating amplifier is made With.Adjust r₅Make the output u of inverse proportion amplifier_bAmplitude is -1.5v～+1.5v, u_bIt is connected to by a₃The biasing circuit constituting.Partially Circuits are output as:

$u_c=\frac{5r_7+r_{11}}{r_8(r_6+r_7)}-\frac{r_{11}}{r_9}{u}_b---(4-4)$

Adjust r₇, make u_bWhen=0, u_c=1.65v, so works as u_bDuring for -1.5v～+1.5v, export u_cList for 0～3.3v Polar signal.

r₁₂And c₃Constitute passive filter, for filtering higher hamonic wave, reduce the interference to sampling.Diode d₁And d₂Structure Become clamp circuit, work as u_c> 3.3v when, d₁Bear forward voltage and turn on, input current potential is restricted to 3.3v.Equally, work as u_c<0v When, d₂Bear forward voltage and turn on, thus input voltage is restricted to more than 0v.

Frequency measurement circuit

The frequency of electrical network is continuous fluctuation, sampling period t_s=1/f, when mains frequency changes, needs adjustment sampling Interval t_s, make to complete the sampling of n point within each cycle.

The capturing unit of tms320f2812 and intervalometer cooperation, can be used to record the saltus step of input pin, preserve signal and jump The count value becoming.The counting time period of hypothesis enumerator is t, count value during signal saltus step is detected twice and is respectively n₁、 n₂, then the interval between two pulses is exactly (n₁-n₂)t.If the sinusoidal waveform of line voltage can be changed into corresponding side Ripple, sends into the capture pin of dsp, can be obtained by the actual frequency of electrical network by above method.The design adopts Fig. 7 herein Circuit realizing this function, in figure u_aIt is the voltage of a point in Fig. 6.

Waveform is as shown in Figure 8.In the positive half cycle of sinusoidal AC voltage signal, LEDs ON, optocoupler exports low electricity Flat, export high level in negative half period.

Synchronization signal detection circuit

IGCT turns in correct time trigger, and synchronizing signal to be had is ensureing.The brilliant lock of gained is calculated in this algorithm Pipe pilot angle is with line voltage zero passage and rate of change is to be to count zero point, with line voltage zero passage and rate of change is negative in the positive moment Moment be 180 °.Synchronizing signal is collected by the capturing unit of dsp chip, starts the signal of timing as internal timer.With u_abAs a example circuit theory see Fig. 9.

Triggers circuit

The effect of thyristor gating circuit is to produce satisfactory gate pole trigger pulse it is ensured that IGCT is when needing Carve and switch to turn on by blocking-up.Because IGCT is half control device, trigger pulse effect out of hand after conducting, in order to reduce damage Consumption, adopts pulse or pulse train more.

Thyristor triggering impulse and triggers circuit should meet claimed below:

(1) width of trigger pulse should ensure that IGCT reliably turns on；

(2) trigger pulse should have enough amplitudes, and the trigger voltage that triggers circuit is provided and the amplitude of trigger current should More than reliable trigger voltage and reliable trigger current, thus ensureing that IGCT reliably triggers, but must not exceed the gate pole of regulation Big allow trigger voltage and maximum allowable trigger current, actual trigger current can be adjusted the specified trigger current for 3-5 times；

(3) trigger pulse being provided should be less than voltage, electric current and the rated power of gate circuit transistor gate, and in gate pole volt Within the reliable toggle area of peace characteristic；

(4) should there are good interference free performance, temperature stability and the electrical isolation with main circuit.

The major function of trigger pulse circuit is that the tcr six phase trigger pulse producing dsp is given isolation after broadening and put Big circuit triggering IGCT.Theory diagram is as shown in Figure 10.

Trigger pulse widening circuit

The trigger pulse of the pwm pin output of tms320f2812 chip is a burst pulse, the reliable width triggering IGCT It is inadequate, need broadening.Using ne555 monostable circuit by pulse stretching, but this chip just starts in low level, therefore front Plus audion not gate, circuit such as Figure 11, circuit input-output wave shape figure such as Figure 12.Burst pulse is through the monostable circuit of 555 compositions Broadening, is sent to isolating amplifier circuit.Pulse width t_wApproximately be given by following formula.

t_w=r_t·c_t·ln3≈1.1r_t·c_t(4-5)

Isolating amplifier circuit

The triggers circuit of IGCT will have enough dielectric strengths, and trigger pulse should be that forward position moment identical is touched by force Send out pulse.The triggers circuit of IGCT has electromagnetism triggering mode, indirect light triggering mode and three kinds of direct light triggering mode.

(1) electromagnetism triggering mode

Also referred to as pulse transformer triggering mode, that is, pulse transformer formula triggers circuit by low level trigger through pulse transforming The gate pole of IGCT is delivered to after device isolation.The first winding input pulse signal of pulse transformer, one, two, three winding is mutual Isolation.It had both transmitted energy, transmits signal again, but can only accomplish potential isolation.This mode advantage is that design is convenient, manufactures letter Single, cost is relatively low, and shortcoming is that high-voltage signal can feed back to triggers circuit and cause when IGCT high back-pressure and the fault such as punctures Damage.So the design is on the premise of using electromagnetism triggering mode, plus a LMDS Light Coupled Device is it is ensured that isolation effect.High level It is low level through optocoupler output level, then deliver to three winding pulse transformer and directly trigger crystalline substance through 8050 rp-drive Brake tube.Figure 13 is the isolating amplifier circuit of the present invention.

According to recommendation, controllable silicon electric current, in 500a 1000a, selects kcb674/211b silicon controlled trigger transformer.Main Want technical specification such as table 10.

The parameter list of table 10 kcb674/211b

Wherein, u transformation ratio；The virtual value of the dielectric withstanding voltage tests voltage of the leave of absence, persistent period between each winding of vp 60s.Fp test pulse frequency；V1 input pulse amplitude (primary pulse transformator)；Tn becomes under v1 and fp of response The nominal transmission pulsewidth of depressor；V2 output pulse amplitude (secondary pulses transformator).

(2) direct light triggering mode

After electro-optic conversion, directly the light of triggering photo thyristor triggers gate pole to trigger.Brilliant with common electricity triggering Brake tube is compared, and direct light triggered thyristor has direct light triggering and built-in bod protects two big advantages so as to reliability carries significantly High, maintenance substantially reduces.But fancy price hinders its promotion and application.

(3) indirect light triggering mode

As shown in figure 14, electric optical trigger utilizes optical fiberss to transmit signal.Optical fiberss have good insulation Performance, has wider frequency response again, it is possible to obtain preferably strong trigger pulse, thus this triggers circuit is in high-voltage dc transmission It is used widely in electricity, svc.Gate pole controls pulse first to become optical signal, delivers to trigger board through optical fiber, and opto-electronic conversion becomes electricity Signal, controls the gate pole of IGCT after shaped amplification.Its electric energy is taken from tens of to hundreds of micro- with resistance-capacitance absorption circuit in series The voltage at the electric capacity two ends of method, or provided by the Secondary Winding of special High-Isolation Transformer.But circuit is complicated.Gate pole triggering letter Number electro-optical conversion circuit adopt hfbr-1521 as electro-optical conversioning device.The photoelectric switching circuit of high potential trigger board, adopts Hfbr-2521 is as electrooptical device.This two devices are generally employed in pairs.

Communication interface circuit

The serial communication interface (sci) of tms320f2812 is one using the asynchronous serial communication sending, receiving double wire system Interface, reduces the expense of cpu during serial communication.Sci module support cpu and other use nonreturn-to-zero ancillary equipment between Digital communication.

Db9 serial communication port after pc machine cabinet is rs-232 level, and dsp is that ttl level could lead to it is necessary to carry out conversion OK.The design, selects max323 to realize the serial communication between f2812 and pc.Particular hardware circuit such as Figure 15, by dgnd, Pc-rx, pc-tx Serial Port Line corresponding with pc couples together, you can realize serial communication.

General i/o port circuit

Liquid crystal display circuit

The design is using being character mode lcd smg12864zk containing character library.Smg12864zk powers for 5v, and the i/ of dsp O output voltage is 3.3v, so needed to first pass through 3.3v before output is to liquid crystal turning 5v chip, using 74lvx3245 can The voltage conversion chip of choice direction.

The specific circuit diagram of the design is as shown in figure 16.Wherein circuit a end is the gpio mouth of dsp, and b end is direct output I/o mouth.When dir (gpiob13) is 1, now level transforms to b end (delivery outlet) by a end (the gpio mouth of dsp), and that is, dsp is straight Connect output 5v level；When dir (gpiob13) is 0, now level transforms to a end (the gpio mouth of dsp by b end (input port) 0), that is, 5v level is directly inputted in dsp system.

The interface signal explanation of table 11 smg12864zk LCD MODULE

Keyboard circuit

Keyboard is used to the basic means of setup control parameter.What the design designed is the keyboard of 7 buttons, by a piece of 74hc165 is incorporated to and goes here and there chip and drive realization, key circuit such as Figure 16, and each keypress function is allocated as follows table.

The interface signal explanation of table 12 smg12864zk LCD MODULE

Keyboard circuit design is as shown in figure 17.

Real time clock circuit

Ds1302 is a kind of clock chip that dallas company releases, and comprises a real-time clock/calendar and 31b in piece Static ram.Chip is communicated with external microprocessor by a simple serial line interface.Real-time clock/calendar chip can With provide the second, point, hour, day, the moon, the information such as year, when the end of month, clock/calendar block sector-meeting is automatically regulated to be the new date, that is, Make to be that to be less than date of 31 days in leap year or month can also be adjust automatically by software design patterns.Ds1302 may also set up 12 hours System or 24 hours systems, made if provided as 12 hours, system can indicate the specific time by am/pm, such that it is able to prevent Time confusion.Specific interface connection signal is as shown in figure 18.

Power circuit

In electronic circuit, the DC source being generally required for voltage stabilization is powered.Small-power regulated power supply is typically by electricity Net power supply, more rectified, filtering, three key links of voltage stabilizing, by grid ac voltage be transformed into electronic system needs stablize Low-voltage direct.The composition of small-power regulated power supply and voltage stabilizing process can be represented by Figure 19.

Mains transformer is the magnitude of voltage required for being changed into the voltage of 220v, then passes through rectification circuit by alternating voltage Become the DC voltage of pulsation.Because the DC voltage that this pulses also contains larger ripple it is necessary to by filter circuit in addition Filter, thus obtaining smooth DC voltage.But such voltage also changes with the change of power network fluctuation, load and temperature. Thus after rectification, filter circuit, also need to connect mu balanced circuit.The effect of mu balanced circuit be when voltage ripple of power network, load and During temperature change, maintain output DC voltage stability.The unidirectional current of+12v, -12v ,+5v, -5v and 3.3v is needed in the design Pressure.Power circuit design is as shown in figure 20.

Claims (1)

1. a kind of static reacance power device, its architectural feature is, based on the control system of dsp, selects Tms320f2812dsp chip is kernel control chip, also includes signals collecting and amplifies electricity with modulate circuit, frequency measurement circuit, isolation Road, telecommunication circuit, i/o interface circuit, Key and display circuit, constitute the control of a basic static passive compensation device System processed, controller is provided with capturing unit, receives frequency measurement circuit, and the adcin interface on controller connects signals collecting and tune Reason circuit, controller is additionally provided with general io port, and io interface circuit connects, and io interface circuit and Key and display circuit Connect, the sci interface on controller is connected with telecommunication circuit, the pwm on controller and isolating amplifier circuit connect, and isolation is put Big circuit connects tcr thyristor controlled series compensation, and controller is also connected with real-time clock.