SU1272449A1 - Electric drive - Google Patents

Abstract

The invention relates to electrical engineering and m. Used in electric drives with reversible valve converter. The purpose of the image, the shadow, is to increase the reliability of the electric drive in operation. The electric drive contains a 1-post electric motor, a current, a reversible valve converter 2, a formers 3, 4 unlocking pulses, a shaper 5 of reference voltages, sources 6, 7, 8 voltage post, a current, an EMF sensor 9, an inverter 10 and two control paths include first diodes 11, 12, first adders 13, 14, comparators 15, .16, differentiators 17, 18, second diodes 19, 20, second adders 21, 22, and current-limiting blocks 23, 24. The drive stably operates in inverter mode when powered from : source of comparable power due to Yeni current limit setpoint gate group working inverter. The load current increases from fasting to a time equal to the recovery time of the power supply voltage. 3 il.

Description

The invention relates to electrical engineering and can be used in electric drives with a reversible valve converter, in particular when powered from an autonomous power source of comparable power.

The aim of the invention is to improve the reliability of the drive in operation.

FIG. 1 shows a functional diagram of the drive; in fig. 2 and 3 are voltage plots in control paths.

The electric drive contains a direct current electric motor 1, a reversible valve converter 2 with two valve groups, a formers 3 and 4 unlocking pulses, a shaper 5 of reference voltages, the first 6, second 7 and third 8 sources of direct current voltage, an inverter 10, two control paths that include the first diodes 11 and 12, the first adders 13 and 14 with two inputs, the comparators 15 and 16, the differentiators .17 and 18, the second diodes 19 and 20, the second adders 21 and 22 with three inputs and blocks 23 and 24 then limited

A direct current motor 1 is connected to the output of a reversible dent converter 2 with two valve groups, the control inputs of each of which are connected to the outputs of the formers 3 and 4 unlocking pulses of the first and second control paths, respectively

The output of the driver 5 of the reference voltages is connected to the first inputs of the drivers 3 and 4, respectively, of the first and second control path.

The cathode of the first diode 11 of the first control path and the anode of the first diode 12 of the second control path are combined, connected to the second inputs of the current limiting units 23 and 24 and are the control input of the electric drive. The anode of the first diode 11 of the first control path is connected to the first input of the first adder 13, and the cathode of the first diode 12 of the second control path is connected to the first input of the first adder 14 of the same control path. The outputs of the first adders 13 and 14 in each

 the control path is connected to the first inputs of the comparators 15 and 16, the second input of the comparator 15 of the first control path is connected to the output of the first source 6 of the DC voltage, and the second input of the comparator 16 of the second control path is connected to the output of the second DC source 7. Outputs

the comparators 15 and 16 in each control path are connected to the inputs of differentiators 17 and 18. The output of the differentiator 17 of the first control path is connected to the anode of the second diode 19 of the same control path, and the output of the differentiator 18 of the second control path is connected to the cathode of the second diode 20 of the specified control path. The cathode of the second diode 19 of the first control path and the anode of the second diode 20 of the second control path are connected respectively to the first inputs of the second adders 21 and 22, the second inputs

which are combined and connected with the second inputs of the first adders 13 and 14 and with the output of the sensor 9 EMF, the input of which is connected to the DC motor 1. Third

The DC voltage source 8 is connected to the third input of the second adder 22 of the second control path and the input of the inverter 10, the output of which is connected to the third

the input of the second adder 21 of the first control path. The outputs of the second adders 21 and 22 in each control path are connected to the first inputs of the current limiting blocks 23 and 24,

the outputs of which are connected to the second inputs of the drivers 3 and 4 of the enable pulses of each control path. The reference voltage driver 5 is provided with leads for connection via a transformer 25 to the supply network.

The drive works as follows.

In each control path on

the first diode 11 (12), the first adder 13 (14), the inputs of which receive a control signal and a signal from the 9 EMF sensor of the electric motor, and the comparator 15 (16), on

the input of which is supplied from the corresponding source 6 (7) of the DC voltage, according to the ratio of the control signal and

3

of the signal from the EMF core sensor 9 of the motor, the magnitude of the inverted current in the transient mode of the electric drive and the degree of supply voltage decrease are predicted. If this voltage reduction has reached a value that determines the tilting of the valves of the valve group of the reversing valve converter 2, which operates in the inverter mode, then the output of the comparator 15 (16) produces a pulse, the duration of which corresponds to the time of existence of the specified mode. Differentiator 17 (18), to the input of which this pulse arrives, generates a signal from it, the time constant of which corresponds to the time variation of the supply voltage of the reverse valve converter 2 when the load on the power source is increased. On the second adder 21 (22, the output pulse of the differentiator 17 (18) is subtracted from the constant voltage of the current-limiting setpoint, so that the total setpoint signal over time repeats the supply voltage of the reversing valve converter 2). in the initial part of the inverter mode and its subsequent increase in accordance with the restoration of the supply voltage, ensures the stable operation of the reversing valve converter 2 without its tilting.

The control voltage for the driver 3 and 4 of the trigger pulses is generated as follows.

In the absence of an input signal (time of Fig. 2 Q), the output of the comparator 15 in the first path of control is negative (Fig. 22), since the positive voltage of the threshold comes from the source 6 to the input of the comparator 16. At the output of the comparator 16, the second voltage control path is positive (Fig. 3j), since the negative voltage of the threshold arrives at the input of the comparator 16 from source 7.

At the first inputs of blocks 23 and 24 of the current limiting of the first and second control paths, there is only a set voltage coming from source 8 and inverter 10.

724494

In the code of current-limiting blocks 23 and 24, in the absence of an input signal, the voltage is zero (Fig. 2 e, Zk). When a maximum positive voltage is applied to the input 5 of the electric drive at time t (Fig. 2a), the output U of the current-limiting unit 23 forms a voltage U equal to the set value,

to be determined by the third source 8 (Fig. 2e). This voltage is fed to the input of the driver 3 of the trigger pulses of the first valve group operating with a rectifier. Thus, the current of the electric motor core at the time of start-up is limited at a level proportional to the magnitude of the setpoint (Fig. 3l). At the output of the current limiting unit 24, the voltage 20 is equal to the magnitude of the input signal (Fig. LC). This voltage is fed to the input of the driver 4 of the trigger pulses of the second valve group, thus preparing

5 it to the inverter mode.

At the outputs of the comparators 15 and 16, the same voltage is maintained (fig. 2 2., 3)

As the motor accelerates

0. The voltage of the EMF from the output of the sensor 9 EMF is fed to the input of the adders 21 and 22 of the first and second control paths (Fig. 2S). At the exit

unit 23, the current limiting first 5 path (Fig. 2e) is formed by the voltage control

and ,,,, and ,,,

where is the control voltage of venupr

0 tiller group operating in the compulsory mode; setpoint voltage, which determines the current limiting level;

EMF core voltage, decreased from sensor 9 EMF. At time t, (reverse) in the second path, a pulse is formed (Fig. 3i), reducing the right setpoint value at the inversion section, as a result of which the level of braking current (dynamic braking) flowing through the second group of gates, 5 operating by an inverter, decreases (Fig . 3l)

When the sign of the input signal changes to a negative diode 12 of the second path, it is shifted in the opposite direction.

Claims (1)

direction. And, since the sign of the EMF voltage at time t does not change, a negative pulse is formed at the first input of the comparator 16 (Fig. Zogs), which, when compared with the voltage of the threshold, forms a pulse at the output of the comparator 16 (Fig. 3j), arriving at differential 17. Moreover, the threshold voltage value formed by the second source NIC 7 should be Unopor U ,, where U is the EMF value creating conditions for the inverter to overturn. The differentiator 18 generates a negative impulse, which is fed to the input of the current-limiting unit 24 of the valve group, which operates with an inverter, and is subtracted from the setting voltage (Fig. 3k). The amplitude of the pulse (Fig. 3i) decreases exponentially with a constant time of the network voltage. The parameters of the differentiator 17 (18) are selected based on the minimum mains voltage at which the current surge in the core circuit at the time of reversal and deceleration does not lead to the inverter tilting. The operation of the first control path when changing the input voltage to a positive one (Fig. 2, S, B, D, D, E, 3L) is similar to the work of the second path. Formula Fig. An electric drive containing a direct current electric motor connected to the output of a reversible valve converter with two valve groups, the control inputs of each of which are connected to the outputs of the formers of the first and second control paths, respectively, the voltage generator, provided with leads for connection to the power supply network, the outputs of which are connected to the first inputs of the first and second control paths of the unpressed pulses, respectively, and two and DC voltage source, characterized in that, in order to increase reliability, a third source has been introduced The nickname of the DC voltage, the EMF sensor of the electric motor and the inverter, and each control path contains a first diode, a first adder with two inputs, a comparator, a differentiator, a second diode, a second adder with three inputs and a current limiting unit, and the cathode of the first diode of the first path control and anode of the first diode of the second control path are combined and connected to the second inputs of the current-limiting block. They are the control input of the electric drive, the anode of the first diode of the first control path is connected to the first input of the first adder, the cathode of the first diode of the second control path is connected to the first input of the first adder, the outputs of the first adders in each control path are connected to the first inputs of the comparator, and the second the input of the comparator of the first control path is connected to the output of the first source of direct current voltage, and the second input of the comparator of the second control path is connected to the output of the second source of the DC current is supplied, the outputs of the comparators in each control path are connected to the inputs of differentiators, the output of the differentiator of the first control path is connected to the anode of the second diode of the same control path, and the output of the differentiator of the second control path is connected to the cathode of the second diode the first control path and the anode of the second diode of the second control path co-u dinene, respectively, with the first inputs of the second adders, the second inputs of which are combined and connected to the second inputs of the first adders and the output of the EMF sensor, whose input is connected to the electric motor, the third DC voltage source is connected to the third input of the second adder of the second control path and the input of the inverter, the output of which is connected to the third input of the second adder of the first control path, the second outputs the adders in each control path are connected to the first inputs of the current-limiting blocks, and the outputs of the current-limiting blocks are connected to the second inputs of the formers of the triggering pulses of each trap KTA management. j C Fi & 2 Fig.Z