DE1763723A1 - Device for asymmetrical control of at least one valve inverter - Google Patents

Description

@ d @@ R DEVICE FOR ASYMMETRIC CONTROL OF MOUTH A VENTIZWFCHSKLBICHTER The present invention relates to devices for the asymmetric control valve judges that are used to reduce the reactive power, which is received by the Ventilwecbselricbter from the electrical network.

It is a device for the asymmetrical grid control of valve switches known with the help of two phase pulse control systems whose control pulses are about the commutators are alternately fed to the control electrode of each valve.

In the known device, the control electrode of each valve is switched alternately from the output of one system of the Pbase pulse control to the output of the other with the frequency that amounts to 0.5 f, where f is the mains frequency, where the phase change of the control pulses in both Systems in different areas with different control angles with an unchangeable sign for their difference is realized .

The gommutatoren are either as synchronous running mechanical Drum, or designed as contact circuits without rotating parts, which are from a Generator controlled, which synchronizes with the grid and on half Grid frequency is matched.

The disadvantages of the above device include the presence of a large number of circuits, the complexity of the switching sequence and the need to use a generator synchronized with the network. This complicates the device to a considerable extent and reduces their reliability.

The invention is based on the object of creating a device for asymmetrical control of at least one valve inverter with a smaller number of circuits to be switched, which are directly controlled both by a generator running synchronously with the network and by control pulses from the phase pulse control system can.

This is achieved in that in the device for asymmetrical control of at least one valve inverter with the aid of two phase pulse control systems which have different control angles with an invariable sign of their difference and whose control pulses are alternately fed to the control electrode of each valve, according to the invention the output of the basic pulse control system is greater than or equal to - A larger control angle is continuously connected to the control electrodes of all the inverter's valves , while a control pulse commutator is switched on in the basic pulse control system with a smaller control angle.

This allows the number of circuits to be reduced by two times.

It is advisable to implement the control pulse commutator with two bistable switching devices, the adjustment times of which are shifted by half a period and each of which commutates the circuits that are acted upon by half of the control pulses from neighboring phases of the base pulse control system with a smaller control angle. In a six-pin valve regulator, each switching device is switched to the common point of the three phases of the phase pulse control system mentioned. For the valve inverters with a control pulse width of more than 60o, transistors with transformers at the output can be used as control pulse commutators, which are combined to form two six-phase groups. Each of the output transformers has an additional winding, which is connected to the input of the transistors of three phases in such a way that the said transformer winding of each odd phase with a transformer of the previous phase of its group and with transistors of the same and a subsequent phase of the other group, while the additional winding of each even phase is connected to transistors of a preceding and the same phase of the second group as well as to a transistor of the subsequent phase of its group.

Such a design significantly increases the reliability of the inverter and does not require a generator that is synchronized with the grid.

Train, better understanding, the invention will be explained in more detail on the basis of preferred selected exemplary embodiments with reference to the accompanying drawings. It shows Fig. I - glass electrical block diagram of the device according to the invention for a 6-phase valve regulator with two switching devices.

Fig. 2 ( a un = d b) - circuit diagram of the Sebalt apparatus in the same device; 3 - the electrical schematic diagram of the phase pulse control system with two transistorized switching devices ; 4 shows the electrical block diagram of the feedback in the device for a valve inverter with the control pulse width of above 60 °; FIG. 5 = the electrical schematic diagram of the device for a valve inverter according to FIG. 4.

As can be seen from FIG. 1, a valve flow controller contains two valve groups 1 and 2, each of which is divided into two subgroups which are in a three-base circuit and are fed by the transformer 3.

The three-phase valve sub-groups of the various groups 1 and 2, which are connected to the phases of the transformer 3 with the same name , are connected in parallel to one another via Balancing® reactors 4 and 5. Two such valve sub-groups, which are connected in parallel in pairs and which are fed by windings of opposite phase of the transformer 3, are switched to parallel operation via the equalizing reactor 6. The control electrodes of the valves of groups 1 and 2 are fed by secondary windings of pulse transformers 7, which are located at the output of two systems 8 and 9 of the phase pulse control with different control angles and invariable signs of their difference.

In system 9 the phase pulse control with a smaller control angle is a control pulse commutator 10 is mounted for commutation of grid pulses, the in the primary circuit of the pulse transformers? lies. To eliminate mutual Loading of the phase pulse control systems 8 and 9 by the equalizing currents of the secondary windings the pulse transformers? becomes in the circuit each of the said secondary windings a diode 11 is connected. They are also used to prevent the occurrence of of incorrect control signals in the windings of the pulse transformers 7 as a result of a Interruption of the magnetization circuit of the transformers mentioned Response of the commutator 10 in the circuits of the primary windings of the transformers 7 the diodes 12 switched on.

In the circuit of the primary windings of the transformers 7 are also discharge resistors 13 switched.

As mentioned above, the control pulse commutator 10 is only mounted in the phase pulse control system 9 with a smaller control angle, while the output of the phase pulse control system 8 with a larger control angle is continuously connected to the control electrodes of all the valves of the inverter. This ensures an alternating with the mains frequency action on the control electrode of each of valves of the two-phase pulse control systems 8 and 9. Since the control angle of the Steuerimpulae that are given to the control electrode of the valve via the commutator 10, is always of the control pulse is lower than the control angle passes to the control electrode of the VEN TILs from Pbasenimpulsateuersystem 8 directly, the valve can be supplied to the control electrode in due Hetzperiode pulses of the two-phase pulse control systems, will be lit with a control angle that is determined by the Pbasenimpulssteuersystem. 9 The valve, no control pulse is applied to the electrodes from the Pbasenimpulssteuersystem 9 is lighted up with a control angle that is determined by the Pbasenimpulssteuersystem. 8 In such a way, the required variation of the control angle is at a twice smaller number of switch contacts, the supply of the control electrode of a certain control angle already lighted valve reaches a second control pulse having a larger steering angle interferes with the normal operation is not of the inverter, but rather increases its reliability in inverter operation.

A defect in the control pulse commutator in today's devices for asymmetrical control resulted in a malfunction of the inverter . In the given forward direction is needed in case of failure in the commutator only the Pbasenimpulasteuersystem 9 off from the network, is introduced whereby the overall Wecbselricbter in undisturbed symmetrical operation.

As a result of the fact that the control pulses are only commutated in the phase pulse control system 9, the number of switching contacts of the control pulse commutator 10 is significantly smaller and the switching sequence is simpler.

In the present device, the control pulse commutator 10 consists of two switching devices, which are designed in the form of changeover contacts 14 and 15, each of which commutates the circuits of the auxiliary bases from the base pulse control system 9, which are acted upon by half of the control pulses. The contact 14 is at the common point of the primary windings of the impulse transformer 7, which are connected to the first three phases of the basic impulse control system 9, and takes care of the impulse distribution between the control electrodes of the two valve groups 1 and 2 as follows: in the right position it switches the opening control impulses of the first and. second phase to the control electrodes of two valves of group 2 and an opening control pulse of the third phase to the control electrode of a valve of group 1; In the left-hand window, it sends the opening control pulses of the first and second phases to the control electrodes of two valves of group 1 and an opening control pulse of the third phase to the control electrode of the valve of group 2. Contact 15 commutates the pulses of the other three phases in a similar manner Way.

In Fig. 2 (a and b), the Umscbaltungsequence of ie the switching circuits of the three neighboring phases. Shows Umacbaltekontakte 14 and 15 (Fig. 1) are indicated by a blackened strip her left position and the opening control pulses 16 and 1 ?, which to the control electrodes of the first, second and third phase of valves of group 1 or 2 are added, and the Similar opening control pulses 18 and 19 are indicated for the fourth, fifth and sixth phases.

From the above diagram, it is seen that the contacts 14 and 15 each include the time period of t1, where t1 is the transit time of the control pulses of the three successive phases, db not less than (. #) T1 = 2400 at a control pulse width of 120 0, the contacts 14 and 15 are with the Frequeemgeschaltet, which accounts for 0.5 mains frequency, their Ansprecbmomente are mutually phase-shifted by ü1 t2 -1800 and when (during the impulse passage in all six power stages) in a given line period one of the contacts in the is on the right , the other contact is in the left . With a constant phase of response torques of contacts 14 and 15, this ensures the commutation of the control pulses in the control angle range of only approx. Wt3 -1200 with a control pulse width of 1200.

To change the control angle in the entire range , the phase of the contact switching should be shifted synchronously with the phase of the control pulses. .

For this purpose it makes the most sense to use the control pulse commutator together with a two-base generator , the output frequency of which is half the mains frequency and which is synchronized with the mains by the output control pulses of the base pulse control system 9. The phase s of the output voltage of this generator is automatically shifted together with the phase of the control impulses, and in accordance with this the point in time at which the contacts are switched will also be shifted.

From Fig. 3 it can be seen that in this case the Pbasenimpulssteuersysvem with a smaller control angle has a Pbase rotator (not shown), a preliminary stage and two output stages of a peak generator. The pre-stage of the peak generator is implemented using transistors 20 and two-level pulse transformers 21. The transformers 21 act on the output stages of the tip generator via the commutator 10. The two power amplifiers of the peak generator are of similar design and contain transistors 22,23 as well as from transition Impulatransformatoren 24 and 2-5. The control pulses are given by the transformers 24 and 25 to the valves of groups 1 and 2, respectively.

The transistors 26 and 27 of the commutator 10 act as reversing contact 14 (FIG. 1), and the transistors 28 and 29 as contact 15. Each of said transistors includes in the conducting state, the input circuits of the three transistors 22 and 23 of the final stage of the peak generator and forwards in the locked state to the base circuits of these transistors, a barrier potential of the power supply source 30 which applies the Spannungsimpulegrö Be exceeded in the secondary windings of the transformers 21 and thus blocks the said transistors. The transistors 31 and 32 are intermediate transistors and serve to open the transistors 26, 27 or 28, 29 via the intermediate transformers 33 and 34. The windings 35 of the transformers Impulstransfowt 21 are provided for the feedback. The diodes 36, resistors 37 and capacitors 38 are intended to limit the overvoltage on all transistors.

The pulses 39 get from the phase rotator to the pre- stage of the peak generator, are formed with the help of the transistors 20 and from the secondary windings of the transformers 21 via the transistors 26-29 to the inputs of the transistors 22 and 23 of the two output stages of the peak generator overall yields.

The commutator 10 works here as follows. Let us assume that at the beginning of the next network period the transistor 31 ge! is locked. Then, the transistor 26 is disabled (in the interturn of the transformer 33 which feeds its base, is missing an opening signal), and in the circuit of the windings (the first, second and third phase) of the transformers 21, which the base of the transistors 22 of the first and second Phase and that of transistor 23 of the third phase, the is the voltage drop applied to transistor 26, the: 8voltage the current source 30 is the same . This voltage is opposite to the opening pulses of the secondary windings of the first, second and third phases of the transformers 21 and exceeds them in size; as a result, the transistors 22 of the first and second phases and the transistor 23 of the third phase are blocked. The transistor 27 is conducting during this time, because although the EMF is missing in the winding that feeds its base, a current flows from the voltage source 30 to the base of the transistor 27 in its circuit and third phase of the transmitters 21 via the emitter collector circuit of the transistor 27 to the inputs of the transistors 23 of the first and second phases and to the input of the transistor 22 of the third phase. In the windings of the respective output pulse transformers 24 and 25, control pulses are induced which reach the control electrodes of the valves. The opening control pulses of the first and second phases thus hit the control electrodes of the valves of group 2, and the opening control pulse of the third phase arrives at the control electrode of a valve of the 1st group.

At the moment when a control pulse of the third phase is formed, the winding 35 of the output pulse transformer 24, which controls a valve of group 1, sends a blocking signal to the base of transistor 32, which blocks the latter. Therefore, at the time of the formation of an opening control pulse of the fourth phase, the transistor 32 is blocked, and an opening pulse is missing in the secondary winding of the transformer 34, which feeds the base of the transistor 29, and the transistor 29 is blocked (analogously to the transistor 26) , while the transistor 28 conducts (analogously to the transistor 27). The pulses are given from the secondary windings of the fourth, fifth and second phase of the transformers 21 via the transistor 28 to the base of the transistor 22 of the fourth phase and that of the transistors 23 of the fifth and sixth phases, while the transistor 23 of the fourth phase and the Transistors 22 of the fifth and sixth phases remain blocked.

The opening control impulses now reach the control electrode of a valve of the fourth phase of group 1 and the control electrodes of valves of the fifth and sixth phase of group 2.

In the production of an opening ssteuerimpulses the secbsten phase of the output pulse transformer 25 which controls a valve in Group 2 given from the winding 35 to the base of the transistor 31 an opening signal, the transistor 31 becomes conductive and to the primary winding of the transformer 33 the voltage of the voltage source 30 is applied; a MM is consequently induced in the windings of the transformer. The NIK induced in the winding 35 of the transformer 33 is supplied to the input of the transistor 31 and continues to hold it in the conductive state . The voltage from the secondary windings of transformer 33, which reaches the base of transistors 26 and 27, makes transistor 26 conductive and blocks transistor 27. Thus, at the beginning of a new period, transistor 26 is conductive, the transistor 2? locked, and the opening pulses from the secondary windings of the first, second and third phases of the transformers 21 meet the inputs of the transistors 22 of the first and second phases and the input of the transistor 23 of the third phase; The transistors 23 of the first and second phase and the transistor 22 of the third phase are blocked, and the opening measurement control pulses reach the control electrodes of valves of the first and second phase of group 1 and the control electrode of a valve of the third phase of group 2.

When an opening control pulse of the third phase is formed, an opening pulse passes from the winding 35 of the output pulse transformer 25, which controls a valve of group 2, to the base of the transistor 32. The transistor 32 becomes conductive, and an additional signal from the winding 35 of the transformer 34 arrives at its input by positive feedback, which holds the transistor 32 in the conductive state after the pulse of the third phase has subsided. The signals of the secondary windings of the transformer 34 make the transistor 29 conductive and block the transistor 28, as a result of which the transistor 29 is conductive and the transistor 28 is blocked at the time the pulse of the fourth phase is formed. The opening pulses are given from the secondary windings of the fourth, fifth and sixth phases of the transformers 21 to the base of the transistor 23 of the fourth phase and that of the transistors 22 of the fifth and sixth phases, while the transistor 22 of the fourth phase and the transistors 23 of the fifth and sixth phases remain blocked.

An opening control pulse of the fourth phase arrives at the control electrode of a valve of group 2, and the pulses of the fifth and sixth phase arrive at the control electrodes of valves of group 1 .

At the moment of the formation of an opening control pulse of the sixth phase from the winding 35 of the output Impulstram formator 24, which controls a valve of group 1 , a blocking signal arrives at the base of transistor 31, which is the signal of positive feedback from winding 35 of the transformer 33 suppressed and the transistor 31 blocks.

The transistor 31 thus proves to be blocked at the beginning of the third network period (at the time a pulse of the first phase is formed) and the cycle repeats itself.

For Ventilwecbselricbter, the control pulse width is above half of 600, the commutation of the control pulses from the phase pulse control system with a smaller steering angle can will realized un- indirectly mutual through the transistors 22 and 23 of the two groups of the second stage from the top of the generator with the help of a system Ring Wückkopplung.

In FIG. 4, according to diagram A, B, C, X, Y amplifiers illustrated the phases of the two groups represents the tip of a generator Secbspbasensystemn the Pbasenimpulssteuerung in their order, wherein, from the outside of six phases (1,2,3,4 5 and 6) of a group of the peak generator, and from the inside six phases Z2'3;4; 5 'and 6') of the other group are shown. In addition, mutual connections between the phases of both groups are indicated by lines and arrows. As can be seen from the block diagram, blocking pulses are supplied from the output of each phase of the peak generator to the inputs of the other three phases and, in accordance therewith, blocking signals from the outputs of the other three phases are supplied to the input of each phase.

The blocking signals are transmitted from the output of each odd phase of the peak generator to the inputs of a passing phase of its own group as well as to those of a phase with the same name and a subsequent phase of the other group of output stages from the peak generator, and from the output of each even phase to the inputs of a preceding and a The same phase of the other group as well as that of a subsequent phase-specific group of the output stages from the peak generator.

Such a system of mutual connections between the phases of the two groups of output stages from the peak generator ensures a strict sequence in the operation of different phases of the two groups of output stages from the peak generator. Let us assume that before the start of a new network period ne first the transistor of the first phase of the first group of output stages from the peak generator (shown in FIG. 4 from the outside) becomes conductive. Then blocking pulses are given from the output of this phase to the inputs of the transistors of the first and second phases of the second group, which reliably block the transistors and ensure the absence of blocking pulses from the outputs of this phase on the inputs of the transistors of the other phases . So the presence ensures an opening pulse at the input of the first phase of the first group, the absence of inhibit pulses at the input of the transistor of the second phase of the first group at the time of feeding its input an open signal from the first stage of the peak generator (only in the event that the pulse width exceeds the distance between the Nacbbarpbasen, ie when the) makes up at a Sechspbasensystems Pbasenimpulssteuerung of about 60o.

The transistor of the second phase of the first group is turned on and blocks the inputs of the transistors of the first and second phase of the second group and the Transistorsec the third phase of the first group, thus opening the transistor of the third phase of the second group meet at the inputs an opening signal from the third phase of the first stage of the peak generator is secured . By the transis- stor the third phase of the second group is opened, it locks the inputs of the transistors of the second phase of the second group and those of the transistors of the third and fourth phase of the first Qrruppe, thus a timely opening the transistor of the fourth phase of the second Group, etc. is ensured.

In the course of two network periods, all phases of the two speak Groups of the output stage of the peak generator ah. alternating in the order which is required according to the diagram) that is shown in FIG. 2 and the cycle repeated.

The basic electrical diagram of the device with the described Variant of a ring system of the feedback is shown in Fig. 5, and it differs from that described in detail when considering FIG Device in that in this case the control pulse commutator through a ring system the negative. feedback is replaced, which with the help of the additional windings 40 the output pulse transformers 24 and 25 and the isolating diodes 41 realized which are the establishment of the connection of each auxiliary winding 40 in three directions realize.

Claims (4)

P A TENT A NSPRUCHE Device for asymmetrical control of at least one valve inverter by two Pbase pulse control systems, which have different control angles with invariable signs for their difference and whose control pulses are alternately supplied to the control electrode of each valve, because the output from the Pbase pulse control system (8) with larger control angle is continuously connected to the control electrodes of all valves of the Wecbselriebters, while a control pulse commutator (10) is switched on in the Pbasenimpulsateuersystem (9) with a smaller control angle. 2. Apparatus according to claim 1, d a d u r c b g ek e n n z e i c b n e t, da8 the Control pulse commutator (10) in the base pulse control system (9) with a smaller control angle is composed of two bistable switching devices (14 and 15) whose response moments are shifted from each other by half a network period, and each of which the circuits commutates that of half of the control pulses of the neighboring phases of the said System are acted upon. 3. Apparatus according to claim 2, dadurcbg ek e nnzeiebnet that in a Secbspbasenventilwecbselricbter each switching device (14 and 15) is at the common point of the three phases of the Pbasenimpulssteuersystem (9) with a smaller control angle . 4. The device according to claim 1, dadurcb marked that in the valve changers with the control pulse width of over 600 as a control pulse commutator in the phase pulse control system with a smaller control angle transistors (22 and 23) with transformers at the output are used, which are composed of two six-phase groups, wherein each of the output transformers (24 and 25) has an additional winding (40) which is connected to the input of the transistors (22 and 23) of the three phases so that the additional winding (40) of each odd phase with a transistor of the preceding phase their group and with the transistors of a phase of the same name and a subsequent phase of the other group, and the additional winding (40) of each even phase is connected to the transistors of a preceding and a phase of the same name of the second group and to a transistor of the subsequent phase of their group.