JPS6149912B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling a rectifier, in particular a method for controlling a semiconductor converter.

The present invention is an AC to DC semiconductor converter integrated into electric traction equipment designed for mainline and suburban railways, for power line substations supplying its output to various converters, and for various DC power and It is suitable for industrial converters designed to supply AC power to consumers.

A known technique in this regard is a method of phase control of semiconductor converters (see West Germany, patent no. 1244941 International Classification HO2m, classification 21d ² , gr.12/03), which method
Each half cycle of the supply voltage comprises one step of applying a control pulse to the main rectifier of the converter with a delay equal to the controlled angle within that half cycle. In this case, what is applied to the load is a transformer voltage represented by a portion of a half-cycle of a sine wave, which portion of the half-cycle of a sine wave determines the voltage value of the rectified voltage. This used and known method does not allow for an appreciable power factor and causes considerable distortion in the primary current with an increase in the audio frequency harmonics that affect the communication line.

Another method of controlling semiconductor converters is known in the following reference (see West Germany, patent no. 847 773 classification/21d ² , gr. 12/03), which partially controls the current in the transformer. and a step of compensating for the inductive power supplied with the aid of a pulse rectifier switch. In this method, a phase control pulse is applied to the main rectifier of the converter every half cycle of the supply voltage and to the conduction blocking rectifier of the converter at the end of the half cycle. According to this method, the converter is a series of series-connected, single-phase, asymmetric, semi-controlled rectifier bridges, the parts of which are matched with switching capacitors, chokes and rectifiers. These elements operate to suppress a portion of the common current of the transformer load through a particular bridge, providing partial compensation of the inductive power of the transformer and traction circuit. The presence of this element increases the size and weight of the overall device.

The method described above is realized in a converter in which inductive elements capable of storing energy, such as capacitors and chokes, are separated from the power source (transformer) by a non-linear element, which is a rectifier. As a result, the smooth change in electromagnetic energy occurring in the transducer is interrupted and the voltage applied to the element tends to rise to a magnitude that significantly exceeds the amplitude of the supply voltage, resulting in the rectifier installation. Power should be increased and insulation should be strengthened. Furthermore, the forced interruption of the smooth electromagnetic process is accompanied by surge vibrations occurring in the traction circuit, which have an increased effect on the communication line.

In addition, there is a method for controlling semiconductor converters (see USSR Inventor Certificate Classification B601 7/16,
HO2m5/16, HO2P13/16), the method utilizes a current oscillation process in a capacitor that is directly coupled to the output of the power source of the converter, i.e. in parallel to the secondary winding of the power transformer. . With this method, phase control pulses are applied in a number of ways to the main and conduction blocking rectifiers of the converter for a complete half cycle of the supply voltage every half cycle of the supply voltage.

In this method, the converter is controlled by turning the same rectifier on and off multiple times. The time intervals of the phase control pulses applied to the main and conduction-blocking rectifiers are not constant and depend on the magnitude of the load, which in turn requires a special set of control methods, which makes the device more complex. reliability is reduced.

Because the same rectifier is used to switch the current multiple times during one half cycle, power losses in the rectifier and capacitor are high and the converter protection devices are complicated. The effects of primary current waveform distortion and control errors reduce power factor and increase interference to communication lines.

The object of the invention is to provide a method for the control of semiconductor converters with improved technical and economical properties.

The present invention is a method for controlling a semiconductor converter that is supplied with power from a transformer, wherein the transformer has a capacitor and a chain yoke arranged in series, and a secondary winding connected in parallel. is shunted by an electronic switch, and the semiconductor converter has at least one single-phase rectifier bridge network with main and conduction-blocking rectifiers and a load connected to the single-phase rectifier bridge network. According to the present invention, the control method includes the following steps:
i.e. every half cycle of the supply voltage and within the complete duration of the half cycle a phase control pulse is
The natural oscillations of the current in the capacitor are alternately applied to the main rectifier during the first half cycle, the natural oscillations starting immediately after the phase control pulse is applied and half the supply voltage. During each cycle and during the second half of the half cycle, phase control pulses are applied alternately to the conduction blocking rectifier during the first half cycle of the natural oscillations of the current in the capacitor, the natural oscillations being phase controlled. A method for controlling a semiconductor converter powered from a transformer is proposed, comprising a step that starts as soon as a pulse is applied.

Advantageously, the method for controlling a semiconductor converter combines two groups of single-phase rectifier bridge networks, i.e. the groups have the same number of single-phase rectifier bridge networks, and each network The control method for a semiconductor converter in which the steps applied alternately to the main rectifiers and then to the main rectifiers of the second group with time intervals equal to half cycles of the natural oscillations of the current in the capacitors and every half cycle of the supply voltage; and during the second half of the half cycle, a phase control pulse is applied to the first group of conduction blocking rectifiers, followed by a second pulse with a time interval equal to the half cycle of the natural oscillation of the current in the capacitor. applying the current to the group of conduction blocking rectifiers.

Furthermore, in order to use the converter to its maximum extent in emergency situations when parts of the converter are inoperable, a method for controlling a semiconductor converter combining several single-phase bridge networks, each supplied with an equal load, is as follows: , i.e. every half cycle of the supply voltage and within the full duration of the half cycle, a phase control pulse is applied to the first and second bridge networks with a time interval between the pulses. ,
The pulses are applied alternately to the main rectifier of each bridge network, and the pulses are similar to the time interval between the pulses applied to the intermediate bridge network equal to 1/3 of the half cycle of the natural oscillation of the current in the capacitor. with a step applied to the penultimate and last bridge network equal to 2/3 of the half cycle of the natural oscillation of the current in the capacitor, and every half cycle of the supply voltage and the second half of the half cycle. Interphase control pulses are alternately applied to the conduction blocking rectifier of each bridge network in the time interval between the pulses applied to the first and second bridge networks, and the pulses are applied to the conduction blocking rectifier of each bridge network in the time interval between the pulses applied to the first and second bridge networks, and the pulses are As well as the time interval between the pulses applied to the intermediate bridge network equal to 1/3 of the half cycle of the natural oscillation, the time interval from the end equal to 2/3 of the half cycle of the natural oscillation of the current in the capacitor and the last step applied to the bridge network.

The control of a semiconductor converter powered by a transformer is
That is, the transformer has a secondary winding and a capacitor each divided into two identical parts, and the semiconductor converter with one single-phase rectifier bridge network is connected to all secondary windings. A semiconductor transducer having two legs having a midpoint and one leg having its midpoint connected to the midpoint of the secondary winding and the midpoint of the capacitor, the semiconductor converter comprising: During each half-cycle of the supply voltage and within the duration of a complete half-cycle, phase control pulses are applied alternately to the main rectifiers of the two legs of the bridge network, followed by half-cycles of the natural oscillation of the current in the capacitors. During each half-cycle of the supply voltage, during the second half of the half-cycle, the phase control pulses are applied alternately to the main rectifiers of the remaining legs of the bridge network with time intervals equal to alternating between the blocking rectifier of one leg of the bridge network and the blocking rectifier of the other leg of the bridge network with time intervals equal to half a cycle of the natural oscillation of the current in the capacitor. Preferably, this is achieved by applying the same amount of energy.

Furthermore, as soon as the phase control pulse is applied to the main rectifier of the bridge network of the semiconductor converter, the opposite side of the bridge network of the semiconductor converter is applied so that the phase control pulse reduces voltage losses due to inductive effects. Preferably, the voltage is additionally applied to the conduction-blocking rectifier in the arm.

Furthermore, a first phase control pulse is applied to the main rectifier of the semiconductor converter in order to prevent the influence of external consumers on the converter operation, and a first phase control pulse is applied to the conduction-blocking rectifier of the semiconductor converter. When the voltage is applied, it is preferably additionally applied to the electronic switch of the semiconductor converter.

The invention will be further described by way of example with reference to the accompanying drawings, in which: FIG.

The method of the invention is realized with the aid of a semiconductor converter 1 (FIG. 1) powered by a transformer 2, in which a series arrangement of a capacitor 4 and a tie yoke 5 is connected to the secondary winding of the transformer 2. connected in parallel. The chain 5 is shunted by an electronic switch 6 made up of two semiconductor rectifiers 7 connected in antiparallel.

The semiconductor converter 1 includes a rectifier bridge network 9,
Group 8 with 9' and Group 1 assembled from rectifier bridge network 11, 11'
It is combined with 0. There may be any number of bridge networks in groups 8 and 10, but
Each of these groups must contain the same number of their networks. The total number of rectifier bridge networks must be expressed as an even number greater than or equal to two.

The main rectifiers 12, 13 are semiconductor controlled rectifiers with rectifier bridge networks 9, 9' and 11, 1.
It belongs to the two arms of 1'. The other two arms of the rectifier bridge network 9, 9' and 11, 11' have main rectifiers 14 and 15 each having a circuit 16 made of fully controlled material and connected thereto. Circuit 16 includes switching capacitor 1
7, a switching chain 18 and an auxiliary diode 19 arranged in series. Furthermore, these last-mentioned arms are combined into conduction-blocking rectifiers 20 and 21 which are connected anti-parallel to the auxiliary diode 19 of the circuit 16.

A load 22 is connected in parallel to each rectifier bridge network 9, 9' and 11, 11', which load is provided in the form of a number of traction motors randomly connected to each other and which Smoothing chokes (not shown) common to the motors or available to groups of motors are also connected in parallel to the rectifier bridge networks 9, 9' and 11, 11'.

As part of an electric vehicle, the semiconductor converter 1 can be controlled in both modes: traction mode when operating as a rectifier and regenerative braking mode when operating as an inverter.

The method of controlling the semiconductor converter 1 operating in rectification mode is as follows.

The total current Id from all rectifier bridge networks 9, 9', 11, 11' of the semiconductor converter 1 flows via the secondary winding 3 of the transformer 2.

Phase control angle α for a given half cycle of the supply voltage before the point at time t ₁ (Fig. 2a)
In this case, the current passing through the load 22, maintained by a smooth choke (not shown) of the load 22, flows via the main rectifiers 12, 13 to the bridge network 9, 9', 11, 11'. A capacitance current i ₃ =i ₄ (Fig. 2 b, c) flows through the circuit of the secondary winding 3 and the capacitor 4, while the voltage applied to the secondary winding 3 and the capacitor 4
U ₃ , ₄ (FIG. 2a) varies according to the shape of the sine wave. In order to simplify the discussion of its contents, we make the following assumptions. That is, it is assumed that the rectified current Id is ideally smooth in the process in the power circuit.

At time t ₁ the phase control pulses are applied to the main rectifiers 15, 12 of the bridge networks 9, 9' of group 3 and to the rectifier 7 of the electronic switch 6. Since the transformer 2 has an inductive resistance, the current of the load 22 of the bridge network 9, 9', which is half of the total current Id, flows through the capacitor 4. As a result, the capacitor 4 starts discharging. When the capacitor 4 discharges, the current i ₃ in the transformer 2 increases. The characteristic oscillation of the current in capacitor 4 from the point of time _t1
At time t ₂ , which is 1/4 cycle away (second
Figure a) Load 22 of the bridge network 9, 9' (the oscillations rise immediately when the phase control pulse is applied)
The total current equal to 0.5Id of transformer 2's secondary winding 3
flows through. However, at this moment, the capacitor 4
The voltage U ₃ , ₄ applied to is at a minimum value and the supply voltage applied to the secondary winding 3 exceeding the voltage applied to the capacitor 4 starts charging the capacitor. The current in the secondary winding 3 continues to rise at a low rate of rise. If the damping of the oscillating process by pure resistance is not taken into account, the current in the secondary winding 3 reaches the value of Id at the time t3, which corresponds to the half-cycle of the natural oscillation of the current in the capacitor ₄ , and the current in the secondary winding 3 reaches the value of Id. is the total current of the load 22 of the bridge network 9, 9', 11, 11' of the group 8, 10 of the semiconductor converter 1. At the time t ₃ the amplitude of the first half cycle of the natural oscillation of the current in the capacitor 4 appears. At this moment, the charging current i ₄ of capacitor 4 is
Reach a value of 0.5Id. At time _t3 , the phase control pulse is in group 1 in semiconductor converter 1.
0 bridge network 11, 11' main rectifier 1
2 and 15. In this case, the current in the load 22 of the bridge network 11, 11' is t ₃
flows through the secondary winding 3 of the transformer 2 at the moment of
On the other hand, the charging current flowing through the capacitor 4 is stopped, and the current of the load 22 mentioned above is changed to the main rectifier 1 before time _t3 .
It passes through 2,13 circuits and has a value equal to 0.5Id. Due to the cessation of the oscillating current in the capacitor 4, the rectifier 7 of the electronic switch is cut off at time _t3 and the chain 5 is turned off.

In order to suppress the current in the transformer 2 within a half cycle of the supply voltage, each step following the reverse order is reversed.

At time t ₄ , the phase-controlled pulse is applied to the conduction-blocking rectifier 21 of the bridge network 9, 9' of group 8 in the semiconductor converter 1 and to the main rectifier 1.
3 and the rectifier 7 of the electronic switch 6.

A current half of Id in the secondary winding 3 of the transformer 2 flows through the capacitor 4 and thereby
The current of the loads 22 of group 8 equal to half of the total current flowing through the secondary winding 3 to start charging flows through the main rectifiers 12,13. The voltage increase applied to capacitor 4 during the charging process is caused by transformer 2.
with a sudden drop in the current i ₃ (FIG. 2b, c) in the capacitor 4 itself and a sudden drop in the current i ₄ in the capacitor 4 itself. After 1/4 cycle of the natural oscillation of the current in capacitor 4, i.e. at time t ₅
At the point, the current i ₄ in the capacitor 4 drops to zero. Meanwhile, the current i ₃ in transformer 2 drops to a value of 0.5Id. At time _t5 , the voltage of the capacitor 4 reaches its maximum value and exceeds the supply voltage value of the secondary winding 3, so that the current of the secondary winding 3 continues to decrease. A reverse current occurs in capacitor 4, and capacitor 4
begins to discharge. After the time t ₆ , i.e. 1/4 cycle from the time t ₅ , i.e. after half a cycle of the natural oscillation of the current in the capacitor 4 , the current i ₃ in the transformer 2 drops to the value of the forced current, so that the capacitor 4 is discharged, The voltage across it reaches the current value of the voltage in the winding 3. The current in the load 22 of the bridge network 11, 11' has by then transferred from the secondary winding 3 to the capacitor 4. At time t ₆ (FIG. 2a), a phase control pulse is applied to the blocking rectifiers 13 and 21 of the bridge networks 11, 11' of group 10. The current in the square load 22 of the bridge network 11, 11' is connected to the main rectifier 1.
2, 13 and suddenly drops in the capacitor 4, thereby driving the rectifier 7 of the electronic switch 6 to cut-off. When the point at time t ₅ coincides with the point where the supply voltage curve intersects 0, this is done by the voltage changing polarity in the secondary winding of the transformer 2, so that the main power of the bridge network 11, 11' is There is no need to drive the rectifier into cutoff.

Therefore, at times _t1 and _t3 , the main rectifier 15,
12 and to the conduction-blocking rectifier 21 at times t ₄ and t ₆ during the time interval t ₁ to
within t ₃ a smooth increase in the current in the transformer 2 and within the time interval t ₄ to _{t 6} a smooth decrease in the current, each such time interval being equal to half a cycle of the natural oscillation of the current in the capacitor 4. .

During the other half-cycle of the supply voltage, the phase control pulses are applied to the bridge network 9, 9', 1 in a similar manner.
1, 11' to the main rectifiers 13, 14, to the conduction blocking rectifier 20 and to the rectifier 7 of the electronic switch 6.

In order to adjust the output voltage value of the semiconductor converter 1, the time at which a phase control pulse is applied to the main rectifiers 12, 15 changes the phase position to the start of a half cycle of the supply voltage (Fig. 3a). , b, c).

In order to improve the power characteristics of the electric vehicle and traction network (not shown), the time at which the phase control pulse is applied to the conduction blocking rectifier 21 is within the phase range from the end of the half cycle to the center of the half cycle of the supply voltage. , ie within the second half of the supply voltage half cycle.

All rectifiers 1 are used to provide inverter operation of the semiconductor converter 1 during regenerative braking of electric vehicles.
2, 13, 14, 15, 20, 21 must be controllable, and adjustment and control are done in the same way as in commutation mode.

FIG. 4 shows the secondary winding of the transformer 2 together with the primary current i ₃ and the current i ₄ of the capacitor 4 at different phases of the phase control pulses in the case of the semiconductor converter 1 of FIG. 1 operating in inverter mode. line 3
Explain the changes in the voltage applied to.

The converter 1 is regulated in the following manner in inverter mode. Here the phase control pulse is
t ₁ , t ₂ are applied alternately to the main rectifiers 12 , 15 of the bridge networks 9 , 9 ′, 11 , 11 ′ in the groups 8 , 10 of the converter 1 , thereby alternating the circuit of the load 22 with an AC power supply. Separate from main line (not shown). Phase control pulses are applied to the conduction-blocking rectifiers 20, 21 of the bridge network 9, 9'11, 11' at times _t3 , _t4 , always at the beginning of a half cycle of the supply voltage. . Note that each time interval t ₁ -t ₂ and t ₃ -t ₄ lasts for a period equal to half a cycle of the natural oscillation of the current in the capacitor 4.

Therefore, during the inverter mode, the main rectifiers 14, 15 of the bridge network 9, 9', 11, 11'
is always driven into cut-off at the beginning of a half-cycle of the supply voltage, i.e. the traction motor (not shown), which constitutes the load 22 and operates as a generator in this mode, is not bridged at times subject to phase control. Circuit network 9, 9', 1
The current is switched on and off in the circuit of main rectifiers 12 and 13 of 1 and 11'.

To reduce and increase the output voltage of the converter 1, phase control pulses are applied to the bridge network 9, 9',
11, 11' to the main rectifiers 14, 15, the points at times t ₁ and t ₂ correspond to half a cycle of the supply voltage, respectively, as indicated by the arrows in FIG. 4a, b, c. Displace to the start and end parts.

The described method of regulating the converter 1 provides an inverter mode characterized by the use of a leading power factor.

According to another embodiment of the invention, the method disclosed above is applied to a semiconductor converter 1 comprising groups 8, 10 (FIG. 5) incorporating bridge networks 9, 11, respectively. Each bridge network has one fully controlled arm. The arm of the bridge network 9 connected to tap A of the secondary winding 3 has a main rectifier 14, a conduction-blocking rectifier 20 and a circuit 19. The remaining arms of bridge network 9 combine into main rectifiers 12, 13, 15. Bridge network 11 connected to output A of secondary winding 3
arm has a main rectifier 15, a conduction-blocking rectifier 21 and a circuit 16, while the remaining arms of bridge network 11 are combined with main rectifiers 12, 13, 14.

The previously disclosed method is also realized in a semiconductor converter 1 comprising bridge networks 9, 11 (FIG. 6) in groups 8, 10, each with a single fully controlled arm. The arm of the bridge network 9 connected to tap A of the secondary winding 3 includes a main rectifier 14, a conduction blocking rectifier 20 and a circuit 16.
has. The remaining arms of bridge network 9 are combined with main rectifiers 12, 13, 15. The arm of the bridge network 11 connected to tap A of the secondary winding 3 has a main rectifier 15, a conduction-blocking rectifier 21 and a circuit 16. The remaining arms of bridge network 11 are combined with main rectifiers 12, 13, 14.

Adjustment of the semiconductor transducer 1 of FIGS. 4 and 5 is achieved in a manner similar to that described above.

When electric vehicles and especially mainline electric locomotives are in operation, forced operating modes similar to emergencies can occur due to partial damage to the electrical equipment used. Such a situation would be as follows. That is, if one rectifier in one bridge network is defective, one traction motor is defective, etc. As a result, the bridge network during operation of the converter, if odd in number, is incompatible with the condition that it is necessary to bisect the converter into two parts with equal loads. To avoid this,
Together with the defective bridge network, it is possible to disconnect a normal bridge network that belongs to another group of bridge networks of the converter. The electrical equipment available in this way cannot be used to its maximum extent and reduces the traction power of the electric vehicle.

In the latter case, the disclosed method uses five single-phase bridge networks 23, 24, 25, 26, 27, each with a load 28 connected in parallel.
This is realized with the aid of a semiconductor converter 1 (FIG. 7) comprising: Any number of bridge networks can be used in the converter 1. Each bridge network 23, 24, 25, 26, 27 has two control arms and two total control arms. The control arm of any one of the aforementioned bridge networks is the main rectifier 2.
Combines with 9,30. The entire control arm of any one of the aforementioned bridge networks is connected to the main rectifier 31,3.
2 conduction blocking rectifiers 33, 34 and a circuit 16.

The semiconductor converter 1 is controlled in such a way that phase control pulses are applied alternately to the main rectifier 31 and then to the blocking rectifier 33 of one of the bridge networks of the converter 1. FIG. 8 shows the variation of the voltage in the secondary winding 3, the variation in the current i ₃ in the secondary winding 3 and the variation in the current i ₄ in the capacitor 4. The phase control pulses are connected to the main rectifiers 31, 3 of the bridge network 23.
2 and then applied to the conduction-blocking rectifiers 33, 32 of the bridge network 23, the phase control pulse is applied to the rectifier 7 of the electronic switch 6. FIG. 8 shows that the alternating application of phase control pulses is applied to the main rectifier 31 of the bridge network 23, 24, 25, 26, 27 as well as during the second half of the half cycle of the supply voltage to the conduction blocking rectifiers 33, 34. , 32 at equal time intervals during a half cycle of the supply voltage. The phase control pulse is connected to the first bridge network 23.
and the time interval t ₁ to _{t 2} (FIG. 8) between when the pulse is applied to the main rectifiers 31 and 32 of the second bridge network 24 and when the phase control pulse is applied to the main rectifiers 31 and 32 of the second bridge network 24. The second bridge network 2 from
The time intervals t ₄ to _{t 5} when the voltage is applied to the main rectifiers 31 and 32 of the bridge network 6 and when it is applied to the main rectifiers 31 and 32 of the last bridge network 27 are equal to each other, and their values are equal to the current in the capacitor 4. each equal to 2/3 of a half cycle of natural vibration. Intermediately between the phase control pulses being applied to the main rectifiers 31, 32 of the bridge networks 24 and 25, 25 and 26 starting in the second bridge network 24 and ending in the penultimate bridge network 26 The time intervals t ₂ -t ₃ and t ₃ -t ₄ (FIG. 8) are also mutually equal and their value is each equal to one-third of the half cycle of the natural oscillation of the current in the capacitor 4.

During the second half of the supply voltage half cycle, the phase control pulses are applied to the first and second bridge networks 2.
3, 24 to the conduction blocking rectifiers 33, 34, then to the penultimate and last bridge network 2
6 and 27 are applied alternately with a time interval t ₆ to t ₇ equal to 2/3 of the half cycle of the natural oscillation of the current in the capacitor 4 . Bridge network 2 with intermediate phase control pulse
The time intervals t ₇ to _{t 8} and t ₈ to t ₉ (FIG. 8) applied to the conduction blocking rectifiers 33 and 34 of 5 and 26 are also equal and their values correspond to the natural oscillations of the current in the capacitor 4, respectively. It is 1/3 of a half cycle. current i ₃
(Fig. 8) rises smoothly in transformer 2 as it passes through the transformer during the time interval from time t ₁ to t ₅ , and rises smoothly in transformer 2 during the time interval from time t ₆ to t ₁₀ . Attenuate. The time interval is the time when the temporal rate of change of the current at the junction becomes equal to each other.
At t ₂ , t ₃ , t ₄ , t ₅ , t ₆ , t ₇ , t ₈ , individual one-cycle curves K-K, -, mm, P-P are joined to prevent sudden surges. .

In the particular case where the transducer 1 has a three-way bridge network, the above-mentioned process can be carried out for 2/2 of the half cycle of the natural oscillation of the current in the capacitor 4.
3 occurs within two equal time intervals in which each value is reached. When using a 4-type bridge network, one intermediate time interval equal to 1/3 of the half cycle of the natural oscillation of the current in the capacitor 4 is used.

In the general case where the number of bridge networks is n, there are (n-1) intermediate time intervals.

The previously disclosed method is realized with the aid of a semiconductor converter 1 (FIG. 9) whose secondary winding 3 is fed from a transformer 2 with an intermediate point 35. The semiconductor converter 1 also comprises a single-phase bridge network 36 connecting a common load 37 which randomly connects a traction motor and a smoothing reactor (not shown). Here, the secondary winding 3 is divided into two equal parts 38, 39. The capacitor 4, which is connected in parallel to the secondary winding 3, is divided into two equal parts 40, 41. The bridge network 36 has two legs 42, 43 whose midpoints are connected to all the secondary windings and a third leg whose midpoints are connected to the midpoint 35 of the secondary winding 3 and the capacitor 4. It has leg portions 44. Each leg 42, 43 has two fully controlled arms. leg portion 42,
One arm of 43 comprises a main rectifier 45, a conduction blocking rectifier 46 and a circuit 16. Legs 42, 4
The other arm of 3 is the main rectifier 47 and the rectifier 4 for blocking conduction.
8 and a circuit 16. The arms of leg 44 are controlled arms and include main rectifiers 49,50. During the adjustment, as in the previous case, electromagnetic phenomena similar to those of the semiconductor converter ₁ of FIG. This is done in the semiconductor converter 1 described above, except that the legs 43, 44 form a path for the current of the load 37 containing the current to be applied to the main rectifiers 45, 50. Due to the natural oscillations of the current in the half windings 38, 39 and the capacitors 40, 41, the current through the secondary winding 3 is reduced by a time interval equal to half a cycle of the natural oscillation of the current in the capacitor 4. The value _{of i 3 ( 10th}
Figure b) is reached. At the time t ₂ (FIG. 10a), the phase control pulse passes through the leg 42 forming a path for the current in the load 37 including all secondary windings 3.
is applied to the main rectifier 47 of .

In a similar manner, the current in the transformer 2 is increased during the second half cycle of the supply voltage when a phase control pulse is applied to the blocking rectifier 46 of the leg 43 to isolate the half winding 39 from the load 37. Depressed for half a period. This advances the point of transition to zero of the supply voltage by a time interval of more than half a cycle of the natural oscillation of the current in the capacitor 4 at the time t ₄
It will be held in After a period equal to half a cycle of the natural oscillation of the current in the capacitor 4, a phase control pulse is applied to the conduction-blocking rectifier 48 of the leg 42 at time _t4 so that the entire secondary winding is disconnected from the load 37. It is said that Figure 10 a, b,
c, d, e are the current i ₃ in the entire secondary winding 3 and the current i ₄ in the capacitor 4, as well as the voltage U ₃ in the entire secondary winding and the currents i 38 , i ₃₉ in half the windings 38, ₃₉ . Shows changes over time.

The current i ₃ is the current in half windings 38, 39
is the sum of the halves of i ₃₈ , i ₃₉ , while i ₄ is the sum of the currents in an equivalent capacitor 4 connected to all secondary windings and comprising two parts 40, 41.

Waveforms U ₃ and i ₃ in FIG. 10 are similar to the waveforms shown in FIGS. 3a, b for transducer 1 of FIG. 1. Figure 11 shows the rectifier 4 in rectification mode.
5, 46, 47, 48, 49, and 50, and FIG. 12 similarly shows the inverter mode of the converter 1.

The curves in Figure 10 are half windings 38, 39
This applies when there is ideal magnetic coupling between the windings, which means that no magnetic flux is lost between the windings.

However, in practical railroad transformers, the loss of magnetic flux or inductive resistance available in the "half-turn-capacitor" circuit quickly damps out the transients that occur when the rectifier becomes conductive for a short period of time.

In the case of good magnetic coupling, this phenomenon does not affect the basic curves represented by voltage U ₃ and current i ₃ .

It is known that in the transformer windings of modern rectifier-inverter converters, a short circuit condition permanently occurs when the rectifier is switched on. In order to reduce this harmful effect, the semiconductor converter 1 is controlled in accordance with the disclosed method in the following manner. When the supply voltage curve crosses 0, conduction begins momentarily and the current in the load 22 (FIG. 9) flows through the rectifiers 14, 1 of the bridge network 9, 9' of group 8.
5 and through the rectifiers 14, 15 of the bridge networks 11, 11' of group 10. When the curve U ₃ of the supply voltage crosses 0 (first
Figure 3) The phase control pulse is connected to the bridge network 9, 9'.
A phase control pulse is applied to the main rectifiers 12, 15 of the same bridge network at the same time as the conduction blocking rectifier 20 in the opposite phase arm of the same bridge network. In this case, the current in the load 22 is transferred from the circuit connected to the rectifiers 14 and 15 to the capacitor 17, the choke 18 and the conduction blocking rectifier 20 under the action of the voltage applied to the switching capacitor 17.
The circuit is switched to a circuit equipped with the following. Since the voltage applied to the secondary winding 3 increases (rectifier 14
(already cut off) is transferred to the circuit combining the capacitor 4 and the secondary winding 3, and at the same time the switching capacitor 17 receives the supply from the secondary winding 3 via the diode 19. It will be charged again. The aforementioned oscillatory process occurs in the secondary winding and in the capacitor 4 with a frequency of natural oscillation of the current in the capacitor 4. At time t ₂ (FIG. 13), a phase control pulse is applied to the main rectifiers 12, 15 (FIG. 1) of the bridge networks 11, 11' of group 10, so that the The current of the load 22 is transferred from the rectifiers 14 and 15 to the rectifier 1.
Transferred to 2,15.

The application of the phase control pulses to the conduction-blocking rectifiers 20 of the anti-phase arms of the bridge network 9, 9' and at the same time to the main rectifiers 12, 15 is therefore carried out by the rectifiers 12, 14 by means of the secondary windings. Provides the condition that the short circuit in line 3 is eliminated.

From the point of time t ₂ (FIG. 13) onwards, the load 22 (first
The current shown in FIG. 1 flows through rectifiers 12 and 15.

A similar phenomenon takes place during the second half cycle of the supply voltage. At the time t ₁ ' (Fig. 13),
When the supply voltage curve passes through 0, the phase control pulse is applied to the main rectifier 1 to eliminate the short circuit in the secondary winding 3.
3, 14 and group 10 bridge network 1
The voltage is applied to the conduction blocking rectifiers 21 of opposite phases 1 and 11'. At time t ₂ ', the phase control pulse is applied to the main rectifiers 13, 14 of group 8.

The fundamental oscillating current in the capacitor 4 stops under the initial zero condition for the current and voltage of the natural oscillation of the current in the capacitor 4. During the time interval between switching, a current corresponding to the total current of the load 22 flows into the transformer 2 and the traction circuit (not shown). The rectifiers of the bridge network 9, 9', 11, 11' are controlled in a given sequence so that there is no change in the current in the winding 3 of the transformer 2 and in the traction circuit during the commutation interval.

The last mentioned condition cannot be strictly satisfied in the case of parallel operation of many units of an electric vehicle fed from a single traction circuit. The frequency of the natural oscillations of the current in each capacitor 4 will be of different magnitude depending on the position of one unit in the feeder of a railway substation, and this also means that a unit will be oscillated during commutation intervals with respect to other units. This is especially due to the fact that the motor voltage is commutated at different angles of control.

Current oscillations at increased frequencies are possible in certain parts of the traction circuit, since the aforementioned case necessarily involves a short-circuit of the transformer windings in the case of ordinary electric vehicles at the end of the commutation of the rectifier.

According to the disclosed method of controlling the semiconductor converter 1, the current i ₃ (FIG. 2) in the transformer 2 rises and falls smoothly in the commutation intervals τ ₁ , τ ₂ (FIG. 14), while the converter A current corresponding to the total current of one load 22 flows into the traction circuit and into the transformer 2 during the aforementioned time interval (commutation interval).

If at time t ₁ the current is diverted to a converter belonging to another electric vehicle that is powered from the same traction circuit, a current change occurs in the given electric vehicle. In order to eliminate this current variation within a complete commutation interval, the circuit of capacitor 4 provides a yoke 5 which operates to reduce the variation as shown in FIG. For this purpose, the main rectifier 12, in which a phase control pulse is of primary importance every half cycle of the supply voltage,
15 (FIG. 1) to the rectifier 8 of the electronic switch 6, which is used to shunt the chain 5 in both directions simultaneously. The second half cycle of the supply voltage
During the half, the phase control pulses are passed to the primary conduction-blocking rectifiers 20, 21 and at the same time to the electronic switch 6.
is applied to the rectifier 7. As a result, the commutation interval τ
₁ , τ ₂ (FIG. 14), the chain 5 is shunted by the conducting rectifier 7 of the electronic switch 6, so that the control and regulating operations carried out in the converter 1 cannot be disturbed. electronic switch 6
The width of the phase control pulse applied to the rectifier 7 is
The phase control pulse is transmitted through the main rectifiers 14 and 15 of the converter 1.
It should be noted that the time interval must be greater than or equal to the time interval between the first and last application of both conduction blocking rectifiers 20, 21.

At the end of each commutation interval, the rectifier 7 of the electronic switch 6 is spontaneously driven into cut-off and the choke 5 is integrated into the circuit of the capacitor 4. This eliminates the occurrence of unnecessary oscillations of the current in the traction circuit resulting from the parallel operation of the transformer 2 and one other electric vehicle.

The above-mentioned disclosed method has a 0.95
Provides a power factor above and makes it possible to eliminate short circuits in the transformer windings when commutating the rectifier of the converter. This is a condition for today's electric vehicles, which necessarily carry out spontaneous commutation. This ensures a two- or three-fold reduction in voltage losses due to inductive effects in the traction circuit and a three- or four-fold reduction in the disturbance behavior of the traction circuit in the communication line.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a first embodiment of a semiconductor converter with two sets of rectifier bridge networks designed to realize the method proposed by the invention, a, b of FIG. c shows the temporal variation of the voltage and current in the elements of a semiconductor converter operating in rectification mode in an intermediate adjustment stage according to the invention, and a, b, c of FIG. 4a, b, c show the temporal variations of the voltage and current in the elements of the semiconductor converter operating in the rectifier mode during the adjustment phase; FIG. FIG. 5 is a circuit diagram of a second embodiment of a semiconductor converter with two sets of rectifier bridge networks designed to realize the method proposed by the invention; and FIG. 6 is a circuit diagram of a third embodiment of a semiconductor converter with two sets of rectifier bridge networks designed to implement the method proposed by the present invention, and FIG. 8 is a circuit diagram of a semiconductor rectifier having a plurality of rectifier bridge networks according to the invention, a, b and c of FIG.
FIG. 9 shows a circuit of a semiconductor converter with a single rectifier bridge network designed to realize the method proposed by the invention, and FIG. 10, a, b, c, d, and e of FIG. 10 show temporal changes in voltage and current in the transformer winding and capacitor of the semiconductor converter of FIG. 9 according to the present invention; a, b, c, d, e, f, k
9 show the time variations of voltage and current in the elements of the semiconductor converter of FIG. 9 during operation in rectification mode according to the invention, and a, b, c, d, e, of FIG.
f, k show the temporal variations of voltage and current in the elements of the semiconductor converter of FIG. 9 during operation in inverter mode according to the invention, a, b, of FIG. 13;
c, of the voltage in the transformer windings and capacitors of the semiconductor converter of FIG. Fig. 14 shows a, b, and c according to the present invention.
2 shows the temporal variation of voltage and current in the elements of a semiconductor converter, reducing the influence of external consumers. 1... semiconductor converter, 2... transformer, 3... secondary winding, 4... capacitor, 5... choke, 6... electronic switch, 8... rectifier bridge network group,
9, 9'... Rectifier bridge network, 10... Group of rectifier bridge networks, 11, 11'... Rectifier bridge network, 12, 13, 14, 15... Main rectifier, 20, 21... Continuity blocking rectifier, 22 …
Load, 23, 24, 25, 26, 27... Rectifier bridge network, 28... Load, 29, 30, 31,
32... Main rectifier, 33, 34... Continuity blocking rectifier, 35... Midpoint of secondary winding 3, 36... Single phase rectifier bridge network, 37... Load, 38, 39... 2
Next winding 3 part, 40, 41... Capacitor 4 part, 42, 43, 44... Rectifier bridge network 3
6 leg portion, 45... Main rectifier, 46... Continuity blocking rectifier, 47... Main rectifier, 48... Continuity blocking rectifier, 49, 50... Main rectifier of leg portion 44.

Claims (1)

[Claims] 1. Semiconductor converter 1 supplied with power from transformer 2
In the control method, the transformer includes a capacitor 4
The semiconductor converter 1 has a secondary winding 3 connected in parallel with a series arrangement of a circuit 5 and a circuit 5, which circuits are shunted by an electronic switch 6.
are main and conduction blocking rectifiers 12, 13, 14,
15 and 20, 21, said rectifier bridge network 9 having a load 22 connected thereto, said control method comprising the following steps: ,
That is, every half cycle of the supply voltage and within the full duration of a half cycle, a phase control pulse is applied to the main rectifier 12, 13, 1 during the first half cycle of the natural oscillation of the current in the capacitor 4.
4, 15 alternately, the characteristic oscillation is started immediately upon application of the phase control pulse, and every half cycle of the supply voltage and during the second half of the half cycle. The phase control pulses are applied alternately to the conduction blocking rectifiers 20, 21 during the first half cycle of the characteristic oscillations of the current in the capacitor 4, which characteristic oscillations are applied immediately when the phase control pulses are applied. 1. A method for controlling a semiconductor converter powered from a transformer, comprising: starting the converter; 2 The semiconductor converter 1 consists of two groups 8, 10 of single-phase rectifier bridge networks 9, 9 and 11, 11' with an equal number of networks 9, 9' and 11, 1
1' and each network 9,9' and 11,11' has an equal load 2 connected to it.
2, a single-phase rectifier bridge network 9,9'
and 11, 11', the control method of the semiconductor converter 1 follows each step of the supply voltage, i.e. for every half cycle of the supply voltage and for the complete duration of the half cycle. The phase control pulse is connected to the bridge network 9 of group 8,
9' are applied alternately to the main rectifiers 12, 13, 14, 15, and then with a time interval equal to half a cycle of the natural oscillation of the current in the capacitor 4.
1, 11' to the main rectifiers 12, 13, 14, 15 and during every half cycle of the supply voltage and during the second half of the half cycle, a phase control pulse is applied to the bridge circuit of group 8. net 9,
bridge networks 11, 1 of group 10 with a time interval equal to half a cycle of the natural oscillation of the current in capacitor 4.
1'. A method for controlling a semiconductor converter according to claim 1, further comprising the step of applying the voltage to the conduction blocking rectifiers 20, 21 of 1'. 3. The semiconductor converter 1 incorporates a plurality of single-phase rectifier bridge networks 23, 24, 25, 26, 27, which have an equal load 28 connected to them. The control method of the semiconductor converter 1 is such that in each of the following steps, i.e. for every half cycle of the supply voltage and within the complete duration of the half cycle, a phase control pulse is applied to the first and second bridge networks. The main rectifier 2 of each bridge network 23, 24, 25, 26, 27 with a time interval between the pulses applied to 23, 24
9, 30, 31, 32 and the pulses are applied to the intermediate bridge network 24, 25, 26 equal to 1/3 of the half cycle of the natural oscillation of the current in the capacitor 4. as well as the time interval between the steps applied to the penultimate and last bridge network 26, 27 equal to 2/3 of the half cycle of the natural oscillation of the current in the capacitor 4 and the period of the supply voltage. Every half cycle and during the second half of the half cycle a phase control pulse is applied to the first and second bridge networks 23, 24.
The pulses are applied alternately to the conduction blocking rectifiers 33, 34 of each bridge network 23, 24, 25, 26, 27 with time intervals between the pulses applied to the The time interval between the pulses applied to the intermediate bridge network 24, 25, 26 equal to 1/3 of the half cycle of oscillation and at the same time equal to 2/3 of the half cycle of the natural oscillation of the current in the capacitor 4. 2 from the end
2. A method as claimed in claim 1, comprising the steps of: applying the voltage to the first and last bridge networks (26, 27). 4 the semiconductor converter 1 is powered by a transformer 2;
The transformer 2 has a secondary winding 3 which is divided into two identical parts 38, 39 and whose identical part 4
0, 41 are corresponding parts 38, 39 of the secondary winding 3
The semiconductor converter 1 with a single-phase rectifier bridge network 36 has a capacitor 4 connected in parallel with the two legs 42, 43 with an intermediate point connected to the entire secondary winding 3. and one leg 44 whose intermediate point is connected to the intermediate point 35 of the secondary winding 3 and the capacitor 4, the control method of the semiconductor converter 1 being carried out in each of the following stages, namely the supply voltage and within the duration of a complete half cycle, phase control pulses are applied alternately to the main rectifiers 49, 50 of the legs 43, 44 of the bridge network 36, after which the characteristic of the current in the capacitor 4 is With a time interval equal to a half cycle of oscillation, a phase control pulse is applied to the main rectifier 47 of the leg 42 of the bridge network 36 and for every half cycle of the supply voltage during the second half of the half cycle. The conduction-blocking rectifier 46 of the leg 43 and the conduction-blocking rectifier 4 of the leg 42 with a time interval equal to half a cycle of the natural oscillation of the current in the capacitor 4.
8. A method as claimed in claim 1, comprising the steps of: 5 As soon as the phase control pulse is applied to the main rectifier 15 of the bridge network 9, 9' of the semiconductor converter 1, the phase control pulse is applied to the main rectifier 15 of the bridge network 9, 9' of the semiconductor converter 1. 5. A method as claimed in any one of claims 1 to 4, further comprising the step of additionally applying a current to the arm conduction blocking rectifier 20. 6 A first phase control pulse is applied to the main rectifier 15 of the semiconductor converter 1 and a first phase control pulse is applied to the conduction blocking rectifier 21 of the semiconductor converter 1. 6. A method as claimed in any one of claims 1 to 5, further comprising the step of additionally applying the voltage to the electronic switch 6.