WO1998043350A1 - Control device for producing hard turn-on pulses for a gate turn-off thyristor - Google Patents
Control device for producing hard turn-on pulses for a gate turn-off thyristor Download PDFInfo
- Publication number
- WO1998043350A1 WO1998043350A1 PCT/DE1998/000787 DE9800787W WO9843350A1 WO 1998043350 A1 WO1998043350 A1 WO 1998043350A1 DE 9800787 W DE9800787 W DE 9800787W WO 9843350 A1 WO9843350 A1 WO 9843350A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- control device
- circuit
- parallel
- capacitor
- switch
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/72—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region
- H03K17/73—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region for dc voltages or currents
Definitions
- Control device for generating hard switch-on pulses for a thyristor that can be switched off
- the invention relates to a control device for generating hard switch-on pulses for a thyristor that can be switched off, which has a series circuit consisting of a capacitor with an antiparallel diode, a first inductance and a switching element, and a recharging circuit, this series circuit being electrically parallel to the output connections this control device and this recharging circuit are electrically connected in parallel to the capacitor.
- GTO Stro rectifier There are several ways to increase the performance of a GTO Stro rectifier, the largest of which is the connection in series of several thyristors that can be switched off, also known as gate turn-off thyristors (GTO thyristors), in terms of system and operating costs Has advantages.
- GTO thyristors gate turn-off thyristors
- GTO thyristors Series connection of GTO thyristors places very high demands on the temporal accuracy of the switching processes. It is required that all GTO thyristors connected in series switch, for example, within approximately 200 nsec. This is only achieved with hard control. Hard control means that the gate current has a significantly higher slope and amplitude than with conventional controls. Due to the hard control, the response times of the GTO thyristors and their control are reduced to about a tenth of the value with conventional control. As a result, the series connection of GTO thyristors is feasible without selecting the semiconductors and without adapting or regulating the control unit.
- a GTO thyristor circuit according to the preamble of claim 1 is known from WO 93/09600.
- the gate circuit contains the two inductances (line inductance and internal inductance of the GTO thyristor), the capacitance connected in series via a switching element and the first diode antiparallel to it.
- the values of this capacitance and the first inductance (line inductance) are chosen such that when the capacitance is discharged via the two inductances, the gate current originating from the capacitance in the first quarter oscillation of that resonant circuit is 0.5 times the anode current to be switched off of the GTO thyristor within less than 5 ⁇ sec, preferably less than 2 ⁇ sec.
- This circuit works in a quasi-resonant operating mode.
- a reload circuit is also provided, which recharges the capacity.
- the capacitance cannot swing through to a negative voltage due to the anti-parallel diode.
- a parallel connection of MOSFETs, a parallel connection of IGBTs, a finely structured thyristor or a GTO thyristor with hard switch-on control can be used as the switching element.
- Field-controlled thyristors (FCTh) or static induction thyristors (SIThs) can also be used.
- FCTh Field-controlled thyristors
- SIThs static induction thyristors
- This international patent application deals primarily with the hard shutdown of a GTO thyristor, whereby an initial current control is followed by a subsequent voltage control is passed over.
- an exemplary embodiment of an entire gate unit for a GTO thyristor is also specified, which largely comprises two similar, parallel circuit parts for switching off and switching on.
- the operating voltage for this gate unit is 200V. All elements of the switching part for switching on can be selected with a reduced load capacity compared to the switching part for switching off, since significantly lower currents are required for switching on and holding when switched on.
- this concept prevents the capacitor from swinging through to a negative voltage with the aid of the antiparallel diode.
- the resonant circuit only builds up the current of the switch-on pulse up to its peak value in a quarter-wave. Then the capacitor voltage is approximately zero and the gate current of the GTO thyristor flows via the anti-parallel diode, the inductor and the switching element. This current is impressed by the inductance and slowly decays from its peak value. The course and duration of the decay are determined by the non-inductive, parasitic voltage drops of the gate circuit and cannot be predicted without precise knowledge of the specific circuit design. In this circuit variant, the entire energy content of the capacitor in the gate circuit is converted into heat and after each pulse the capacitor must be charged from 0V. This means that this circuit variant has a high power loss and its power requirement is high.
- the invention is based on the object of specifying a control device for generating hard switch-on pulses for a thyristor which can be switched off, which no longer has the disadvantages mentioned and which manages with a substantially smaller supply voltage.
- This object is achieved according to the invention with the features of claims 1, 2 and 12, the inductive design provided for the hard shutdown being used.
- the capacitor By using a second inductor, which is connected upstream of the antiparallel diode, the capacitor is charged to a negative voltage at the end of a half-oscillation, which ideally corresponds to the amount of the positive initial voltage.
- the resonant circuit would naturally oscillate back to a positive capacitor voltage.
- the capacitor After the swing-back process, the capacitor is charged again to a positive voltage, which, however, is lower than the initial voltage. After the switching element is blocked, the capacitor is recharged to the initial voltage.
- This circuit variant is therefore much less lossy and has a much lower power requirement.
- the decoupling diode can be dispensed with if a reverse-blocking converter valve is used as the switching element.
- the recovery time can no longer be set separately from the time of the switch-on pulse.
- the ringing back time is shorter than the time of the switch-on pulse.
- the ring-back current has approximately the same level as the switch-on pulse. Because of the short
- the reload time constant can be shortened, which means that this circuit variant manages with a pulse interval of less than 200 ⁇ sec.
- the second circuit variant several circuit variants are electrically connected in parallel. Part of this second circuit variant connected in parallel is tuned to three times the frequency and one third of the amplitude of the other part of this second circuit variant connected in parallel. As a result, a trapezoidal switch-on pulse is generated when the individual switch-on pulses of different amplitude and frequency are superimposed. As a result, a switch-on pulse with a predetermined amplitude can be generated.
- a decoupling diode must be connected upstream of each switch.
- This inverse-parallel diode of the MOSFET or IGBT basically consists of a conventional PN diode that is parallel to the channel. Their electrical data therefore correspond to that of a conventional Si rectifier.
- a decoupling diode By using a decoupling diode, the ringing back current cannot swing back through the anti-parallel diode paths of the power MOSFETs or IGBTs.
- a decoupling Diodes are diodes with the shortest possible switching times.
- the Schottky diode is a diode with a very short switching time. In addition, it has a lower forward voltage compared to a silicon junction diode, so that this Schottky diode also has a much smaller power loss.
- a constant current source is electrically connected in parallel with the capacitor and the inductance of the series circuit.
- the switching element remains switched on for the entire duration of the thyristor that can be switched off, since the switch-on pulse decays aperiodically by itself.
- This switching element can thus switch the continuous gate current in addition to the switch-on pulse, so that a suitable switching element for the permanent gate current is no longer required.
- the constant current source charges the capacitor to the value of its supply voltage. This means that a separate reload circuit for the capacitor is no longer required.
- control device for generating hard switch-on pulses for a thyristor that can be switched off are illustrated schematically.
- IG 1 shows a basic circuit diagram of a first circuit variant of a control device according to the invention
- the IG 2 shows a basic circuit diagram of a second circuit variant of a control device according to the invention
- IG 3 shows an advantageous embodiment of a control device according to the invention, which consists of several circuit variants according to FIG. 2
- IG 4 shows a first embodiment of a first circuit variant according to FIG. 1, where IG 5 shows significant signal curves of the embodiment according to FIG. 4 in a diagram over time t
- IG 6 shows a second embodiment of a second
- FIG. 8 illustrates an embodiment of a further control device according to the invention and FIG. 9 shows the significant signal curves according to the embodiment 8 illustrates in a diagram over time t.
- FIG. 1 shows a basic circuit diagram of a first circuit variant of a control device according to the invention for generating hard switch-on pulses for a thyristor 2 which can be switched off.
- This control device has a series circuit 4 and a recharging circuit 6.
- This series circuit 4 has a capacitor C1 with an anti-parallel diode D1, an inductor L1 and a switching element 8.
- This series circuit 4 is electrically connected in parallel to the output connections 10 and 12.
- the recharge circuit 6 is electrically connected in parallel to the capacitor C1.
- a second inductor L2 is connected upstream of the anti-parallel diode D1. The value of this second inductor L2 is significantly larger than the value of the first inductor L1.
- a decoupling diode D2 is connected between the first inductor L1 and the switching element 8.
- the capacitor C1 is charged to a positive voltage by means of the recharging circuit 6. This charged capacitor C1 is switched to the gate-cathode path of the GTO thyristor 2 by means of the inductor L1 and the switching element 8. In the process, the capacitor C1 discharges and a discharge current is produced in the form of an approximately sinusoidal oscillation (FIG. 5). This half-sine wave is the switch-on pulse for the GTO thyristor 2.
- the capacitor C1 and the inductance L 1 are dimensioned such that the current half-wave meets the requirements for a switch-on pulse. At the end of the half-oscillation (t2 in FIG.
- the capacitor C1 is charged to a negative voltage, which ideally corresponds to the amount after the positive initial voltage. In the real case, however, the amount of this voltage is lower.
- the resonant circuit consisting of capacitor C1 and inductor L1, would naturally oscillate back to a positive capacitor voltage.
- the decoupling diode D2 it is ensured that the current of this ring-back process does not flow via the gate-cathode path of the GTO thyristor 2, but via a separate ring-back circuit 14.
- the capacitor C1 is again positive Voltage loaded, but due to the inevitable losses is less than the initial voltage.
- FIG. 2 shows a basic circuit diagram of a second circuit variant of a control device according to the invention for generating hard switch-on pulses for a thyristor 2 that can be switched off. This control device differs from that according to FIG.
- the anti-parallel diode D1 is not connected in parallel to the capacitor C1, but rather to the series connection of the capacitor C1 and the inductor L1.
- the second inductance L2 according to FIG. 1 is no longer required.
- their function is taken over by the inductance Ll.
- the ring-back time is thus somewhat shorter than the time of the switch-on pulse, since the internal inductance of the GTO thyristor 2 is not effective for the ring-back.
- the anti-parallel diode D1 Since the oscillation current is amplitude-equal to the switch-on pulse, the anti-parallel diode D1 must be dimensioned and constructed like the decoupling diode D2. Since the recovery time is at most the time of a switch-on pulse, the time for recharging the capacitor C1 can be shortened, so that this variant can manage with a pulse interval of less than 200 ⁇ sec.
- each subcircuit generates a switch-on pulse with a frequency and an amplitude, these being superimposed on the output connections of this embodiment. If one half oscillation of one circuit is tuned to three times the frequency and one third of the amplitude of the half oscillation of the other circuit, a trapezoidal switch-on pulse is obtained as a result of the superposition of the two switch-on pulses.
- FIG. 4 shows a first embodiment of a first circuit variant according to FIG. 1.
- the capacitor C1 consists of a plurality of film capacitors connected in parallel. For example, ten film capacitors with a capacitance value of 6.8 ⁇ F are connected in parallel. Electrolytic capacitors are not suitable because they are unipolar and have too high a replacement series resistance.
- the switching element 8 consists of a plurality of power MOSFETs 16 connected in parallel.
- a decoupling diode D2 is connected upstream of two switches 16.
- a Schottky diode, for example, is provided as the decoupling diode D2.
- the decoupling diodes D2 and the power MOSFETs 16 are combined in groups and these are connected in parallel as a whole.
- two power MOSFETs and a decoupling diode D2 form a group.
- the resonant circuit inductance for the switch-on pulse is formed from the inductance L1 together with the parasitic inductance of the structure.
- the value of the parasitic inductance caused by the structure is relatively uncritical, since this inductance is included in the function of the circuit.
- the value of the inductance L1 is, for example, 15 nH.
- the resonant circuit 14 is formed from the inductance L2 and the anti-parallel diode Dl.
- the inductance L2 is specifies that the reverberation process lasts, for example, 20 microseconds.
- the peak value of the oscillating current is thus approximately 300 A, so that a single antiparallel diode D1 can be used.
- the value of the second inductance L2 is, for example, 636 nH.
- a Schottky diode can also be provided for the anti-parallel diode D1.
- the power MOSFETs 16 are switched off at some point in the currentless state if the voltage across the capacitor C1 is still negative during the oscillation phase. This is the case in the time window between t2 and t3 in FIG. In the example, the time constant R1 »C1 of the recharge is significantly longer than the duration of the oscillation processes at 100 ⁇ sec.
- a delay choke L3 or an additional switch 20 can be inserted, with which the resistor R1 can be switched off during the oscillation time.
- This switch can be controlled with the logically negated control signal S1 of the switch 16 if its switch-off time is set at the end of the permissible time window (t3 of FIG. 5).
- This circuit with the specified design can generate the next pulse approximately 350 ⁇ sec after the end of a switch-on pulse. If this time interval is to be reduced, so the oscillation time and the RC time constant must be shortened. Without the switch-off option, the RC time constant must be a multiple of the recovery time.
- FIG. 5 shows the significant signal profiles of the embodiment according to FIG. 4. These are the capacitor voltage u c , the gate current I G , the ring-back current i L2 and the switching signal Sl.
- the capacitor C1 is charged to a positive voltage U C ⁇ and the switching signal S1 changes from low to high.
- the capacitor C1 discharges and the gate current I G flows in the form of a sine wave.
- the gate current I G is again zero and the capacitor Cl is charged to a negative voltage U c2 .
- the oscillation process begins at this point in time t2 and is only completed at point in time t4.
- the sign of the capacitor voltage u c changes .
- the switches 16 Up to this point in time t3, the switches 16 must be blocked so that no further vibration passes through the gate-cathode path of the GTO thyristor 2. At the time t2, the switch 16 can be locked at the earliest. This time range t3-t2 is a permissible time window for the switch-off time. At time t4, the capacitor C1 is again charged to a positive voltage U c3 , which differentiates it by a voltage difference ⁇ U C from the voltage U C ⁇ at the start of the switch-on pulse.
- the capacitor C1 is recharged to the voltage U C ⁇ .
- This reloading time is, for example, 100 ⁇ sec, the time for the swing-back process being, for example, 20 ⁇ sec and the time for the semi-oscillation being 3 ⁇ sec, for example.
- FIG. 6 shows a second embodiment of a second circuit variant according to FIG. 2.
- the embodiment differs from the embodiment according to FIG. that the anti-parallel diode Dl is no longer connected in parallel to the capacitor Cl, but to the series connection of capacitor Cl and inductor L1.
- the ring-back current i L2 (negative half-oscillation of the gate current I G in FIG. 7) approximately corresponds to the switch-on pulse
- this diode D1 must now be dimensioned in the same way as the decoupling diode D2.
- the advantage of this embodiment is that, according to FIG. 7, the time for the oscillation process is at most equal to the time for the half oscillation for the switch-on pulse. This can also shorten the reload time constant. That is, the sum of these times is, for example, 31 ⁇ sec, whereas the sum of the times in the exemplary embodiment according to FIG. 4 is, for example, 123 ⁇ sec.
- Another advantage is that several of these embodiments can be electrically connected in parallel, which are tuned differently, whereby, for example, a trapezoidal switch-on pulse is generated by superimposing several switch-on pulses.
- the embodiment according to FIG. 8 differs from the embodiments according to FIGS. 4 and 6 in that a swinging of the capacitor C1 to negative voltages is prevented with the aid of a diode D3.
- the resonant circuit only builds up the current of the switch-on pulse up to its peak value in a quarter-wave.
- the capacitor voltage u c is then approximately zero and the gate current of the GTO thyristor 2 flows via this diode D3, the inductance L1 and the switches 16.
- This current is impressed by the inductance Ll and slowly decays from its peak value.
- the course and the duration of the decay are determined by the non-inductive parasitic voltage drops of the gate circuit and can therefore not be predicted without precise knowledge of the specific circuit design. say.
- the constant current source 22 responsible for the permanent gate current is provided here, which is connected in parallel with the series connection of capacitor C1 and inductor L1. Since this circuit can practically not swing back, the decoupling diode D2 can be dispensed with.
- the antiparallel diode D3 must be dimensioned in the same way as the antiparallel diode Dl of FIG. 6.
- This switching element 8 can thus switch the continuous gate current in addition to the switch-on pulse, so that a separate switching element is no longer required for the permanent gate current.
- the constant current source 22 charges the capacitor C1 to the value of its supply voltage.
- a separate recharge circuit 6 is therefore no longer required for the capacitor C1.
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Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP98925401A EP0968566A1 (en) | 1997-03-21 | 1998-03-16 | Control device for producing hard turn-on pulses for a gate turn-off thyristor |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19711966.2 | 1997-03-21 | ||
DE1997111966 DE19711966C1 (en) | 1997-03-21 | 1997-03-21 | GTO-converter with abrupt switch-on of GTO-thyristors |
Publications (1)
Publication Number | Publication Date |
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WO1998043350A1 true WO1998043350A1 (en) | 1998-10-01 |
Family
ID=7824218
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/DE1998/000787 WO1998043350A1 (en) | 1997-03-21 | 1998-03-16 | Control device for producing hard turn-on pulses for a gate turn-off thyristor |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0968566A1 (en) |
DE (1) | DE19711966C1 (en) |
WO (1) | WO1998043350A1 (en) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0246478A1 (en) * | 1986-05-22 | 1987-11-25 | BBC Brown Boveri AG | Semiconductor power switch |
DE3617185A1 (en) * | 1986-05-21 | 1987-11-26 | Licentia Gmbh | Arrangement for controlling gate-turn-off thyristors, particularly of higher power |
EP0381849A1 (en) * | 1989-02-07 | 1990-08-16 | Asea Brown Boveri Ag | Fast power semiconductor circuit |
DE4324184A1 (en) * | 1993-07-19 | 1995-01-26 | Siemens Ag | Method and circuit arrangement for generating a firing pulse for a converter valve |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DD275971A1 (en) * | 1988-09-30 | 1990-02-07 | Elektroprojekt Anlagenbau Veb | CIRCUIT ARRANGEMENT FOR INCREASING THE SLOPE OF THE SHUT-OFF CURRENT OF A GTO THYRISTOR |
DE4136181A1 (en) * | 1991-11-02 | 1993-05-06 | Asea Brown Boveri Ag, Baden, Aargau, Ch | GTO THYRISTOR CIRCUIT |
-
1997
- 1997-03-21 DE DE1997111966 patent/DE19711966C1/en not_active Expired - Fee Related
-
1998
- 1998-03-16 WO PCT/DE1998/000787 patent/WO1998043350A1/en not_active Application Discontinuation
- 1998-03-16 EP EP98925401A patent/EP0968566A1/en not_active Withdrawn
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3617185A1 (en) * | 1986-05-21 | 1987-11-26 | Licentia Gmbh | Arrangement for controlling gate-turn-off thyristors, particularly of higher power |
EP0246478A1 (en) * | 1986-05-22 | 1987-11-25 | BBC Brown Boveri AG | Semiconductor power switch |
EP0381849A1 (en) * | 1989-02-07 | 1990-08-16 | Asea Brown Boveri Ag | Fast power semiconductor circuit |
DE4324184A1 (en) * | 1993-07-19 | 1995-01-26 | Siemens Ag | Method and circuit arrangement for generating a firing pulse for a converter valve |
Also Published As
Publication number | Publication date |
---|---|
DE19711966C1 (en) | 1998-06-10 |
EP0968566A1 (en) | 2000-01-05 |
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