摘要:
Zum Antakten eines drei- oder mehrphasigen Stromrichters (SR) mit Phasenfolgelöschung, der mit einem eingeprägtem Zwischenkreisstrom (la) gespeist wird, wird der Zwischenkreisstrom (Id) zunächst auf kleine Werte begrenzt und die Taktfrequenz auf ihren von der Steuerung vorgebbaren Maximalwert erhöht. Sobald die Spannung an den Kommutierungskondensatoren (C K ) eine ausreichende Höhe erreicht hat, wird der Zwischenkreisstrom (l d ) zeitverzögert auf den Anfahrwert erhöht und anschließend die Taktfrequenz nach einer Zeitfunktion auf die optimale Anfahrfrequenz reduziert.
摘要:
It is presented a voltage source converter comprising a first converter device. The first converter device comprises: a plurality of director valves, wherein each director valve comprises two anti-parallel thyristors provided in a bridge for switching between two states, the bridge being provided in at least one phase leg connected to two a first pair of direct current poles and comprising a midpoint connected to an alternating current, AC, terminal; and at least one commutation cell connected to a respective one of the at least one phase leg, wherein the commutation cell is controllable to reverse-bias a thyristor of at least one director valve of a connected phase leg when the thyristor is to stop conducting current. By providing anti-parallel thyristors in the director valves, greater control is possible. For instance the current between the DC poles can be turned off using the director valves.
摘要:
A current source power conversion apparatus is provided which makes a resonance phenomenon not to be generated even if a float inductance exists in a commutation auxiliary circuit. It is composed of a plurality of switching legs 3, 4, 5. In the respective switching legs, first thyristors 31, 41, 51, first diodes 32, 42, 52, second diodes 33, 43, 53, second thyristors 34, 44, 54 are connected in series from a DC voltage positive side in the order, each of first reverse blocking self-turn-off devices 35, 45, 55 is connected between a connection point of the first thyristor and the first diode and an AC terminal, so that the AC terminal direction is a forward direction, each of capacitors 36, 46, 56 is connected between a connection point of the first diode and the second diode and the AC terminal, and each of second reverse blocking self-turn-off devices 37, 47, 57 is connected between a connection point of the second diode and the second thyristor and the AC terminal, so that the AC terminal direction is a reverse direction.
摘要:
A power converter (300) includes at least one leg (301) with a first string (302) including a plurality of controllable semiconductor switches (330), a first connecting node (310), and a second connecting node (312). The first string (302) is operatively coupled across a first bus (306) and a second bus (308). The at least one leg (301) also includes a second string (304) operatively coupled to the first string (302) via the first connecting node (310) and the second connecting node (312), wherein the second string (304) includes a plurality of switching units (334). The first string (302) includes a first branch (314) and a second branch (316). The second branch (314) is operatively coupled to the first branch (312) via a third connecting node (318) and the third connecting node (318) is coupled to a ground connection.
摘要:
The invention provides a converter (2a), and in particular a current source converter (CSC). The converter includes a bridge (14a) having an ac terminal (16a-16c) for each of one or more ac lines, and first and second dc terminals (18a, 18b). A converter arm is connected between each respective ac terminal (16a-16c) and the first dc terminal (18a), and between each respective ac terminal (16a-16c) and the second dc terminal (18b). Each converter arm includes a first power semiconductor switching device (24) capable of being turned 'on' and 'off' by gate control, as a GTO, and having a recovery time. The converter (2a) is adapted to be operated in one or more inverting modes, particularly in an naturally commutated inverting mode, that is, when a second GTO in a brigde arm is switched on, before first, already conducting, GTO in a parallel bridg arm is switched off, when the current through the first GTO has decreasd.
摘要:
In a load commutated inverter induction motor drive a parallel capacitor bank (C d ) is used in part to force-commutate the thyristors (TH-6TH) of the inverter (INV) as triggered by auxiliary thyristors (XTH, YTH) and turned off by the other part of the capacitor bank (C c ).
摘要:
In a load commutated inverter induction motor drive a parallel capacitor bank (C d ) is used in part to force-commutate the thyristors (TH-6TH) of the inverter (INV) as triggered by auxiliary thyristors (XTH, YTH) and turned off by the other part of the capacitor bank (C c ).
摘要:
In an energy converter of the type utilising a series-resonant bridge circuit (1), containing at least two thyristors (6A, 7A, 6B,7B) diodes (8A, 9A, 8B, 9B), antiparallel connected thereto and a high-frequency output transformer (12), and an energy buffer (2), a control circuit (3) is incorporated for generating trigger pulses for the appropriate thyristors in response to the energy of the buffer (2). The energy converter comprises a switching circuit (24) incorporated in at least one of the supply lines of the supply source to the series-resonant circuit for ensuring that the diode, antiparallel connected to the last-conducting thyristor, starts to draw current immediately after this thyristor is blocked. The control circuit (3) furthermore generates signals indicative of the presence of current flowing through the diodes (8A, 9A, 8B, 9B) which signals control the supply of the trigger pulses to the thyristors (6A, 7A, 6B, 7B).