SU1325642A1 - Method of adjusting load of rectifier converter - Google Patents

Abstract

The invention relates to converter technology and can be used to control power static gate converters. The aim of the invention is to improve the accuracy of regulating | ШН1И, M in & 03 tt№l of its load current under variations in network voltage and counter-emf load. The goal is achieved due to the fact that one of the components of the reference signal of the next valve is formed by integrating the corresponding network voltages, and the other component is the product of the instantaneous values of the EMF load and the time interval elapsed from the moment the previous valve was turned off. To implement these operations, integrators 7, 8, and 9 with a reset and adders 1, 2, and 3 by the number of converter gates are entered into the device, integrator reset control unit 10, load EMF sensor 16, valve state sensor 17, functional converters 18 and So, Sb FIG. /

Description

19 and multiplication unit 20. Thus, the formation of the reference signals e; | The gates are designed to predict variations in network voltage and

one

The invention relates to the field of converter technology and can be used to control power static valve converters.

The purpose of the invention is to improve the accuracy of current control in case of variations in the supply voltage and the counter-emf load.

Fig. 1 shows a functional diagram of a device that implements the proposed method for controlling the load current of a valve converter in Fig. 2; an example of a converter according to a three-phase zero scheme; Fig. 3 are diagrams explaining the operation of the indicated device; in fig. 4 and 5 - variants of possible schemes of functional converters; Fig. 6 is a diagram of the change in time of the EMF of a DC motor with independent excitation in a stationary mode of intermittent current.

A device that implements the proposed method contains a network voltage sensor (DN) 1-3, adders 4-6, integrators 7-9 with reset by the number of converter gates, a integrator reset control unit (BEADS) 10, two analog signal switches ( QS) 11 and 12 with the number of channels equal to the number of gates, control angle limiting unit (BFU) 13, comparator 14 with summing inputs, master signal source (IZS) 15, load EMF sensor (DE) 16, valve state sensor (DSV ) 17, the first and second functional converters (FP) 18 and 19, as well as the power supply unit (BP) 20 and pulse distributor (RI) 21,

The inputs of the DN 3 are connected to the sources of network voltages, and their outputs are connected to the corresponding inputs of the adders A-6, the inputs of the BEADS 10, the COP 12 and the inputs of the BOU 3, DNs can be performed, for example. according to the amplifier circuit

protivo-edu nagruchku and proactively take into account their T1ri | ) distribution (phase of the trigger pulse of the next valve, 6 Il.

An optocoupler isolator, the reset point of the integrators 7-9 is connected to the outputs of the BEADS 10, and their outputs are connected to the inputs of the KC t1 switch, Switches II and 12 can be performed, for example, 5 on the 284KH1 analog switch chips, the BEAD 10 in this case consists of three channels, each of which can have an adder, a first-harmonic filter of the mains supply, made, for example, according to a band-pass filter scheme, and a reset pulse shaper, made, nX Trimer, on an integrated circuit of a 155АГ1 one-oscillator, Key control inputs; 11 and 12, and respective inputs BOU 13 connected to the second 21 RI outputs, the first outputs are connected to the gate electrodes of the transducer valves. Moreover, the control inputs of the key KS I1, which commutes the reference signal for the given valve, and the key KS

12, switching the voltage signal of the power supply network, acting in the anode circuit of the previous valve, is connected to the same output RI 21. Pulse distributor 21 can be performed, for example, by connecting a counter and a decipher in series. The RS signals controlling the operation of the keys of the COP 11 and COP 12 are received from the outputs of the decimator, and the control pulses of the valves are formed by elements And by the number of valves, the first inputs of which are connected to the output of the control unit

13, and the second inputs are connected to the corresponding outputs of the descrambler. The output of the COP 11 is connected to the second summing input of the comparator 14, the output of which is connected to the input of the control unit 13, the Output of the COP 12 is connected to the input of the control unit 13 and through the FP 19 to the second totalizing input of the comparator 14, the output of the source signal, which can be used as any regulated source

voltage connected to the first summing input of the comparator 14, which is also connected to the output of the DE 16, connected, in addition, with the input of the BOU 13 and the first input of the BP 20, as the DE you can use a tachogenerator. current, and BP can be performed on the chip analog multiplier. The output of the FP 18 is connected to the second input of the BP 20, and the output of the specified block is connected to the second summing input of the comparator 14. The output of the virgins 17 is connected to one of the control inputs of the FP 18 and 19, to the other control inputs of which the output of the CPU 13 is connected with an input of RI 21,

The functional transducer 18 (FIG.) Can be made according to Scheme 25.

In Fig. 4, and containing the phases of the mains supply from the output source of a DC bias voltage (IC) 22, the integrator 23 with a reset, and the OR element 24, the output of the IC 22 is connected to the input of the integrator 23, the output which is the output of the FP 18, the reset control input of the integrator 23 is connected to the output of the OR element 24, the inputs of which are connected to the outputs of the virgins 17 and BOU 13 (FIG. 1).

The JQ functional converter 19 (FIG. 1) can be made according to the scheme shown in FIG. 5 and containing an integrator 25 with a reset and an OR element 26, the integrator input being connected to the output of the CS 12 (Fig. 1), and its output being the output of the AF 19. The reset control input of the indicator 25 is connected to the output of the OR element 26 whose inputs are connected with outputs of virgins 17 and BOU 13 (figure 1).

The method of controlling the load current of the converter valve can be determined by examining the operation of the device, the functional diagram of which is shown in FIG. 1, timing diagrams explaining his work are shown in FIG. 3, where e, e, eb are the voltage of the phases of the supply network; Ujji, (6) the output voltage of the converter;

A) UBk, j (6) and Ujviirp - valve reference signals for continuous current mode; S, BO and - pulses reset integrators at the output of the WCD 10 (Fig. 1); Uj - the reference signal of the continuous current mode

valve at the outlet of the COP 11 (Fig. 1); .f-, the supply voltage of the previous (n-l) -To valve on the outlet. COP 12 (Fig. 1); Uv signals on

DN 1-3 through adders 4-6 arrive at the inputs of the corresponding integrator 7-9 (Fig. 1). At the output of the integrator, valve reference signals are generated for the continuous current mode (Fig. 3b). The instants for setting zero initial conditions of the integrators are determined by the temporal position of the pulses Spy,, Sjj generated by the WCD 10 (Fig. 36) at the moments when the first harmonic passes through the zero of the sum of network voltages input to the input of the corresponding integrator at the control angles of this ventil at F The outputs of the integrators are supplied to the switches of the switch KS 11, which are controlled by the gates RI 21 8, Sj, Sc (Fig. 1). These gates are produced in accordance with the order of operation of the valves, so that in the interval of forming the reference signal of the next valve until the generation of its control output, the corresponding gate is equal to a logical one. This closes the key COP 11, which controls this gate. So, for example, when forming the reference signal of the valve connected to the mains voltage e, (fig. 2),, yj a. It is obvious then., I.e. at the output of the COP 11, the signal Ujn at each instant of time is equal to the reference voltage of the continuous current mode of the next valve (Fig. 3 Sv).

Similarly, a KS 12 switch (fig, 1) from a DN 1-3 signal forms an e (..) Signal, proportional to η each time point of the network voltage acting in the venom anode circuit

40

45

55

the outputs of the OP 19 and 18 (Fig, 1); d is a signal proportional to the emf of the load at the output of the DE 16 (FIG. 1); third component of the reference signal

next p-th valve at the outlet of BP 20 (FIG. 1); U (, p and U ,, is the resulting reference signal and the control signal on the summing inputs of the comparator 14 (Fig, 1); ut and l control pulses to the outputs of the CPU 13 and the signal of virgins 17 (Fig, 1),

The diagrams below illustrate the operation of a valve converter for measles of a DC motor with independent excitation (DC) B — a steady-state discontinuous current mode (Uj const) under sinusoidal supply voltage.

Signals proportional to eg 5

0 phase of the mains supply, from the outputs

Q

DN 1-3 through adders 4-6 arrive at the inputs of the respective integrators 7-9 (Fig. 1). At the output of the integrator, the reference signals of the gates are formed for the continuous current mode (Fig. 3b). The instants for setting zero initial conditions of the integrators are determined by the temporal position of the pulses Spy,, Sjj generated by the WCD 10 (Fig. 36) at the moments when the first harmonic passes through the zero of the sum of network voltages input to the input of the corresponding integrator at the control angles of the given valve at F, The output signals of the integrators arrive at the switches of the switch KS 11, which are controlled by the gates RI 21 8 ", Sj, Sc (Fig. 1). These gates are produced in accordance with the order of operation of the valves so that in the interval of forming the reference signal of the next valve until the generation of its control output, the corresponding gate is equal to a logical one. This closes the key COP 11, which controls this gate. For example, when forming the reference signal of a valve connected to the mains voltage e, (Fig. 2),, j a. It is obvious then., I.e. at the output of KS 11, the signal Ujn at each instant of time is equal to the reference voltage of the continuous current mode of the next valve (Fig. Sv).

Similarly to a KS 12 switch (FIG. 1), a signal e („.) Is formed from the signals DN 1-3, which is proportional to each network voltage momentary to the voltage of the venom 5 anode circuit

0

five

five

5 1 included last (previous

valve (Fig. 3g).

The time position of the control pulse of the next valve d corresponds to the front of the output signal of the comparator 14 (Fig.) S, which is formed at the moment of equality of the resulting reference and control signals (Fig. Zi, k). The control signal and, on the first summing input, the parametrator represents the sum of the signal from the output of the EMF load sensor DE 16 e and the reference signal and, from the output of the IHS 15. These signals are proportional to

back-EMF load and voltage drop from a given current 1 at the active load resistance K ", therefore

and, e, (e, +), (O

where K is the proportionality coefficient.

The control pulses d from the output of the BDU are fed to the input of the RI (Fig. 1), where the next pulse d produces the Resultative reference signal of the next nth gate Uon, .., forms the 25 switching of the gate of the RI, and the pulse

tl lttyttstto from ml mlgggpltattsgtlpply anotfT-

C at the second summing input is distributed to the control electrode of the corresponding valve.

Parator as an algebraic sum of three components:

Uon (. () () (). (2)

where and (if) is the signal at the output of the FP 19 (Fig. Zd);

signal at the output of KS 1I (Fig. Sv);

the output signal of BP 20 (Fig. ЗЗ), formed as a result of multiplying the signals ДЭ 16 е (Fig. Зж) and ФП 18 и, (Fig. Зе);

(3)

and ,, (a)

izp ()

where K,. „- coefficient

Bc

()

the multiply block transmissions. The signal from the output of the comparator 14 S j is fed to one of the inputs of the BOU 13 (FIG. A 1), where the angle of control of the next valve is limited to the positive voltage region on it and the control pulse ci is generated in duration (FIG, ЗЖ). B CU checks two conditions for positive voltage of the valve in continuous current mode.

W tv

and condition the positivity of the voltage on the tT M valve in the discontinuous current mode

% L, e, (, I.

45)

.

0

five

0

The condition of the formation of a pulse control valve can be formulated in such a way

The control pulse of the next valve is formed if: the reference and control signals of the next valve become equal with a positive voltage on the valve or the indicated signals are not compared until the point in time where the voltage at the next valve becomes negative. In the latter case, an impulse 0 is formed at the moment of changing the sign of the voltage on the fan. This impulse cannot turn on the valve, but it switches the RI (Fig. 1) and, therefore, the entire control system of the converter to form the reference signal of the next valve.

The control pulses d from the output of the BOU are fed to the input of the RI (Fig. 1), where with the next pulse d produces 5 switching of the gate of the RI, and the pulse

 switching strobes RI, and momentum

tl lttyttstto from ml mlgggpltattsgtlpply anotfT-

is distributed to the control electrode of the corresponding valve.

In addition, the pulses d are fed to one of the control inputs of the functional converters 8 and 9 (Fig. 1), to the other input of which signals are sent virgins 17. Note that the equality corresponds to the presence of a load current (Fig. 3a), B indicated The AF of these signals forms a control signal for the reset of the in- 8 "(Fig. 4 and 5)

tegrator

.

(6)

At the output of the FP 18 (Fig. 4), a signal U is formed, equal to

 k-- s.- | -.) 1 (7)

 (V-H

where ey WoT, is the integrator time constant (Fig. 4) Tu, in angular units; uSj - circular frequency network; the current time t in angular units;

)

the moment of switching off the previous (n-1) -th valve.

At the moment of generation of the next control pulse, the output signal of the AF 18 is reset (Fig. Ze). The third component of the reference signal of the next valve U. () (fig.Zz)

ih

is formed at the output of the block by multiplying BP 20 (Fig. 1) by equation (3), which, with the substitution (7), is converted to

C. (-) ё ,,. (eight)

functional Converter OP 19 (Fig, 5) generates the output signal according to the equation

about

-) 9-: I, Par. /)

fo

(9)

 M 2. R

 (p-1)

moreover, at the moment of generation of the next control pulse, the integration result is zeroed (Fig. A). f5

Then the equation of the reference signal of the next valve (fig. Zi) after substitution in (2) (8) and (9) is converted to

 one: ()

; -07- 1% l.

na

.. R (pl

one)

(ten)

In order to improve the accuracy of the development of a given current in the proposed method of current control, the load operation integrates the back emf by the operation of multiplying the instantaneous value of the emf and load by the duration of the corresponding time interval. Then the equation of the algorithm for generating the reference signal of the next n-th valve in the relative system of relative units is written as

C) d | .f) -, ° L

Oip

- L .- (n.,. O)

Cn-l) 0

Thus, when forming the reference signal of the next valve in accordance with (11), it is possible to ensure the working out of the specified current at the output of the valve converter without error.

In the invention, the reference and control signals are formed in accordance with the proposed law. Indeed, this follows from equation (1) with in the received system of relative units.

g

(.) - C ;.

(12)

The algorithm of forming the second component of the reference signal in the proposed device in accordance with the described description of its operation and in

The system of relative relations can be written down by the equation 1

 -, - K. -3)

Substituting (13) into (10), where the parameters are chosen as the following,

21

m

G in - and - ± -. I „

(PMC, r1

Determine the resulting reference signal generated in this device:

five

5 0 g

0

about

five

i -0П Ю) cW g 1

- 1, py ().

 tn-n

Taking into account the considerations outlined above, it can be easily seen that the proposed method of controlling the converter load current allows to achieve the goal, which is to improve the accuracy of current control with variations in supply voltage and counter-emf load. This effect is achieved due to the formation of the reference signals dp of the valves in such a way as to predict the above-mentioned variations and to take them into consideration in the determination of the phase of the triggering pulse of the next valve,

Claims (1)

Invention Formula The method of regulating the load current of the converter -, in accordance with the fact that they form the clumsy signal of the next ventilation; as the sum of three components, the first of which is proportional to the I – IH tegral, taken with the opposite sign from the voltage of the phase of the previous valve in the interval of its nonconductive state, compares the reference and iii equal signals, at the moments of their equality form pulses valve controllers and nullify the integration result, limit the valve control angles to the positive voltage region on it and distribute the control pulses over the valves, characterized in that, in order to improve the accuracy of current control during variations mains voltage and counter-emf load. the control signal is formed as the sum of the current reference signal and the proportional counter-emf signal of the load, the second component of the reference signal of the next valve is proportional to the integrap of the voltage difference between the previous and the next valve, and the result of the integration is zeroed once the network at the time of zero crossing of the first harmonic of the sum of the integrated voltages at the valve control angles is more than 180 el. degrees, and the third component of the reference signal of the next vent The sludge is shaped in proportion to the product of the instantaneous values of the back-EMF of the load and the time interval that is generous from the moment the previous valve was turned off.  it8.J