SU782108A1 - Reversible power-diode electric drive - Google Patents

Description

(54) REVERSIBLE VENTILATION ELECTRIC APPLE

one

The invention relates to electrical engineering, namely, reversible valve actuators with separate control of a two-set converter, or with a single-set converter and a reverser.

Known reversible valve actuator containing a DC motor connected to a two-way valve converter with separate control, with two pulse-phase control systems, and an artificial switching unit} - The closest valve actuator containing a DC motor , connected to a two-way two-way valve converter with separate control. . pulse-phase control systems, an artificial switching unit that includes separation diodes connected by anodes to the phases of the network supplying the converter, each of which includes a tone sensor, two switching thyristors connected by cathodes to the load, anodes to a capacitor, to the second output of which are connected cathodes of the separation diodes, and parallel to the capacitor a recharge circuit with a recharge thyristor 1.2 is connected.

A disadvantage of known devices is the poor use of a voltage converter, limited in most cases to safe inversion conditions.

Usually, under the conditions of safe inversion, the advance angle of the inverter must be at least f) min-g 30-40 el. hail. In powerful

15 valve electric actuator angle of delay. the switching on of the rectifier is practically equal to the angle ahead of switching on the inverter (oL min). Consequently, the use of a voltage converter from the conditions of a safe inverted 1 is

 ,

1SOV, 8bb-o,

where is silt, is the maximum rectified voltage of the converter at d. .

Thus, the use of known reversible venile transducers with an average voltage of 30 percent exceeds 80%.

The purpose of the invention is to increase the yajn6sty and convincing .yo HdttollbaidBaHHH

inverter.

This goal is achieved by the /) additionally introduced an inverter mode sensor with two cut-off diodes, six

elements and, two elements OR, seven elements of the time delay, and the control inputs to the firing thyristors are connected to the direct outputs of the elements OR, inverse outputs

KitBray are combined, and through a time delay element are connected to the control input of a recharge thyristor, three inputs of each of the OR elements are connected. The outputs of the six elements And, and the three inputs of each element And connected the outputs of the current sensors of the corresponding phases of the converter, through six delay elements in the belt - auxiliary channels of successive phases of the corresponding system of pulse-phase control and, through cut-off diodes, the corresponding output of the inverter sensor mode.

The drawing shows a diagram of the electric power supply system. ..,. j ,,, - .. “.,. w. ,, i; .x .... zi

The device contains a reversible three-phase bridge converter (any other circuit can be straightened) consisting of bridges 1 and 2, anchor of DC motor 3 in one load circuit of the converter, two systems of pulse-phase control 4 and 5 {one for each set of converter ), block artificial comg. Utaciv the composition of dividing diodes b, connected by anodes to the phases of the network supplying the converter., switching thyristors 7 and 8 connected by catDDi to different load terminals 3, and anodes to switching capacitor 9, which is connected to another plate of small; a capacitor, diodes b and anode, recharged thyristor 11. The cathode of thyristor 11 is connected to one pin of throttles 12, inserted into a single inlet that is connected by a capacitor charge source 10, a common capacitor lining and 7, 8. The logic circuit contains two elements OR

13 and 14, the direct outputs of which are connected to the control inputs of the switching thyristors 7, 8, and the inverse jacks are combined and each eight time delay section 15 is connected to the control output of the thyristor 11. CohodaD ale. 13 and 14 are connected to the outputs of the corresponding elements And 16 and 17 (three elements And for each set of converter). To rtepBtJM in HBDay BL (; Element And connected to the outputs according to 782108

current sensors 18, .containing current transformers and diode rectifying bridges, to the second inputs two outputs of the sensor 19 of the inverter mode (via cut-off diodes 20 and 21), and to the third inputs - auxiliary; Lena channels of the systems of pulse-phase control 4 and 5 (through elements 22 and 23 of the time delay), with each third input of the AND element being connected to a channel of its own, as well as the next phase, which is marked by a letter marking. The input of the sensor 19 of the inverter mode through the comparator 24 signals, proportional to the set and the actual speed.

The circuit works as follows. In the rectifying mode of operation of any of the two sets of the converter, i.e. E motor operation mode of the drive, to the input of the comparator 24 do two signals: Uz signal l, proportional to the specified speed, and Zf - Signal proportional to the actual speed. Their difference is, firstly, to control the voltage of the converter, as in all known systems, the IbgB drive a valve, i.e. It is supplied as a control signal; the signal is in blocks 4 and 5 (it is not shown in the diagram, as it is typical). Secondly, MJ is fed to the input of the sensor 19 of the inverter mode. At the second input of this sensor. The actual speed Uq is received. The coincidence of the polarities Ucj, and U characterizes the rectifying mode; If IF and U have opposite polarity, the investment mode is t6p71.

As the sensor 19, a standard three-way transistor relay can be used. When the coincidence of the polarities and or the relay is off, i.e. In the rectifier mode of the converter, the block 19. is turned off and at the outputs of all the elements 16 and 17 (elements I) there is no signal, even with signals from the dates of the current 18 and: from the elements 22 and 23 zado | 5zhky.

Consequently, in the rectifier mode of the converter, the signal at the direct outputs of the elements 13

and 14 is zero and the switching thyristors 7 and 8 are locked. Condenser 9 charge: wives from a source of 10 plus on the right oykladka. . . When the drive enters the inverter mode, the polarity of the signals U (j

and & U are opposite, with the polarity of Zf being determined by the direction of rotation, therefore the sensor 19 is connected with a plus on one of its two outputs; for example on the top. AT

In this case, through a constant diode 20

The signal enters the inputs of the elements 17. The other two inputs of these elements receive signals from the current sensors 18 and from the auxiliary channels of unit 4 (pulse-phase control systems). However, in the case of normal inversion, the current signal, for example, from phase A never coincides with the signal, arriving at the same element of the AND-auxiliary channel of phase B through time delay element 22. Indeed, during normal commutation, the current in phase A should decrease after the supply of an unlocking pulse to the thyristor of the charming phase (c). The time delay has a response time longer than the switching time of the current and the operating phase into the next one in any normal mode. Therefore, the signals from sensor 18 and delay element 22 do not coincide in time.

Disturbance of switching in the inverter mode due to, for example, a decrease in the voltage in the pitcher. AC, will inevitably cause the current to be drawn in the operating phase and the coincidence of the signals from the current sensor 18 and the delay unit 22. Element AND is turned on and a signal from its output. Is supplied to the input of element OR 14 at the direct output of which voltage appears, which leads to switching on of the thyristor 7 and transfer of the load current to the capacitor. After the current in the working phase A drops to zero, the element 14 is turned off (the signal from the current sensor 18 disappears) and the current appears in the next phase, since the corresponding power thyristors are triggered by unlocking pulses through the main channels of block 4 (in the drawing, indicated by the dotted line ), and the voltage on the capacitor 9 in the process of recharging with the load current changed polarity. It prevents the further flow of the load current through the capacitor.

Thus, the circuit restores normal switching and the inverter overturning is prevented.

When the element 14 is turned off, a voltage appears at its inverse output and a thyristor 11 is turned on through the time delay element 15. A resonant overcharge of the capacitor 9 occurs along the circuit: left; facing thyristor 11, choke.12 - right facing. The return circuit is reset to its initial position, and at the next breakdown of the switching cycle, the operation cycle is repeated. A time delay is necessary to turn on the thyristor 11

prois.zoschlo after turning off thyrist.ora 7, T-.e. pr. after restoration of crmmutations. Note that the current from the source 10 must be less than the holding current of the thyristor 7, which is easily achieved, since the source 10 is needed only for

 original edr yes capacitor,. 9 and compensation for losses, i.e. may be very low power with large internal resistance.

The operation of the circuit when inverting via a set of 2 transducers is considered. The operation of the circuit when inverting through set 1 is similar. The only difference is that from the sensor 19 the signal enters through the diode 21 to the element 16, which results from the thyristor 8 writing and the power gates are forced to switch to the generator 1.

For normal operation of the circuit, it is necessary that the pulse duration,

5 steps to the power thyristors from the impulse-phase control system were longer than the switching time. In modern systems, this condition is usually satisfied. If necessary

0 working unlocking pulses can be duplicated by repeated alarm pulses.

The proposed scheme provides reliable inversion with a sudden decrease in network voltage over 25.

therefore, the converter can be more fully used in terms of voltage: the angle P can be chosen from the conditions, n, where сУ is the angle taking into account the asymmetry of 30 pulses in the system of pulse-phase control and the asymmetry in the network; - the angle of setting of the thyristor locking properties. 5 For industrial installations email. hail. Consequently, the use of a converter according to the safe inversion conditions is cos 10®so, 98.

0

Claims (1)

Invention Formula Reversible valve drive containing a DC motor connected to a two-way valve converter with separate control, with two systems of pulse-phase control j an artificial switching unit, including separation diodes connected by anodes to the phases of the network supplying the converter, each of which includes current sensor, two commuting thyristors. The cathodes connected to the load, the anodes - to the capacitor, to the second terminal of which the cathodes of the separation diodes are connected, and parallel to the capacitor is a recharge circuit with a rechargeable thyristor, 6 tons of h and n so that, in order to increase reliability - and increasing the use of the voltage converter, it is additionally connected to the sensor of the inverter mode with 5 two cut-off diodes, six ele