SU1585880A1 - Rectifier drive with direct power supply from ac mains - Google Patents

Abstract

The invention relates to electrical engineering. The aim of the invention is to improve the weight and size parameters. This goal is achieved by supplying each of the three electroplated windings of a synchronous machine (CM) 2 from the corresponding phase of the three-phase network through one of the bridge switches 4, 5, 6, which are made on the keys with two-way conductivity. The switch also performs the function of the rectifier due to the switch control unit 15 analyzing the polarity of the supply voltage using comparators 16, 17, 18. The drive has position-dependent pulse-width modulation of the phase voltage CM 2 using a digital angle sensor 7 , the persistent storage device 8 and the pulse-width modulators 9, 10, 11. The frequency of rotation of the CM 2 is controlled by means of a controlled frequency divider 12. 3 ill., 1 tab.

Description

where f, is the frequency of the generator 13,

n is the controllability

Letter 12 frequency. The frequency of the pulses of the controlled divider 12 frequency f is

fu f;

(3)

,, where 4g is the code of the control module

impact.

Consequently, the resulting value of the coefficient -u is

g

2 - 1

sin (-x-fi). (four)

Logic control unit 15 processes the signals e, h, s, respectively, from the output of the comparator 16 (17, 18), the PWM output 9, 10, 1, and the rise of the reverse 14 and generates the key control signals 34 (FIG. 2). 5.6 in accordance with the table, where A, B, C, D are the key management signals 34 (FIG. 2) of the switches 4, 5, 6. I.

The logical variables e, h, s are defined as follows.

The output signal e of the comparator 16 (17, 18) is equal to a logical zero with a negative voltage at its input and a logical one otherwise. The value h of the output signal of PWM 9 (10, 11), equal to one, determines the flow of current in the first second, third phase of the synchronous machine, h 0 corresponds to the dynamic braking of the synchronous machine by short-circuiting the i-th phase. The value s of the signal of the phase current direction determines the flow of the left to right (Fig. 2) at s 0 and from right to left otherwise.

From the table, minimized logical equations are obtained for the synthesis of logic control unit 15

And e (hs + hs) + e (sh + sh) e ® (s © h),

With es + es e Ф s, (5)

In e © (s © h), D e Ф s.

The single value of the logical variables A, B, C, D determines the closed state of the keys 34 and vice versa.

- five

S sing 4g © sing sin (5tf +

| ri) j,

(6)

20

five

what sets the valve actuator reverse when sing ijg 1 by simultaneous

 inverting the signals s of all phases, which leads to a change in the direction of current in all phases and a change in the sign of the torque of the synchronous machine 2,

, 2

) 5 The sip signal; n sin (/ Jif +, - iTi) is shot

from the i-ro output of the sign bit ROM 8. Thus, in accordance with the indicated algorithm of operation of the logic control unit 15, the direction of the phase current is determined by the signal s and does not depend on the polarity of the alternating voltage applied to the switches 4, 5 and 6, which in the drive simultaneously perform the functions of the alternating voltage rectifiers and are implemented on the keys with two-way conductivity (triacs, field effect transistors).

One variant of the key circuit 34 on an induced channel transistor is shown in FIG. 3

The use of comparators analyzing the polarity of an alternating voltage of 5 voltage in the logic control unit 15 makes it possible to combine the functions of a switch and a rectifier, thereby excluding expensive power diodes and smoothing filters from the drive circuitry. In addition, the effect of the fluctuations in the average value of the phase voltage on the torque is insignificant, since the switches are powered from different phases of a three-phase AC network, which leads 5 to mutual compensation of torque variations due to individual phases of the synchronous machine.

50

Claims (1)

Invention Formula An AC-powered valve actuator containing a three-phase synchronous machine, each galvanically developed winding of which is connected to a separate bridge switch, a digital angle sensor, the shaft of which is connected to the shaft of a three-phase synchronous machine, and the output Connect to the address input of the permanent storage device, the code outputs of which are connected to the information inputs of the corresponding latitude-pulse modulators, the charging inputs of which are connected to the output of the controlled frequency divider, the code input of which is the control input, and the clock input is connected to the generator, a reverser, a logic control unit connected to the inputs of the switches, and a three-phase power transformer, the primary winding of which is intended to be connected to the network, which is different m that, in order to improve the mass and size indicators, the persistent storage device is additionally equipped with sign outputs, and the control logic unit is filled with a three-channel control with three inputs and four outputs for each channel, and contains a comparator in each channel, three logical elements EXCLUSIVE OR, two inverters, the sign outputs of the persistent storage device are connected to the input of the reverser, each output of which is connected to the first inputs of the first and second logic elements EXCLUSIVE OR corresponds to channel of the logical control unit, the second input of each first logic element is EXCLUSIVE OR connected to the output of the corresponding pulse-width five Q 0 five modulator, and in each channel of the control logic block, the output of the first logic element EXTRACT OR, whose output is connected to the input of the first inverter, and the first output of the corresponding channel, the output of the second logic element EXCLUSIVE OR is connected to the input of the second inverter and is the second output of the corresponding channel, the outputs of the first and second inverters are respectively the third and fourth outputs of the corresponding anal, and the second input of the second exclusive OR logic element is connected to the output of the comparator, whose input is connected to one of the corresponding power input switch, the terminals of each phase of a three phase transformer secondary winding connected to inputs of respective power switch. FIG. 2 ABOUT -Wi with - Rig.Z