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Chapter 1 Review of Power Electronics Converters . Power electronics refers to control and conversion of electrical power by power semiconductor devices wherein these devices operate as switches. . "Electronic power converter" is the term that is used to refer to a power electronic circuit that conv

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    2. Chapter 1 Review of Power Electronics Converters

    3. Power electronics refers to control and conversion of electrical power by power semiconductor devices wherein these devices operate as switches.

    4. Harmonics

    7. Semiconductors Switch types Diode

    8. Thyristor

    9. Thyristor types: Phase controlled thyristor(SCR) Fast switching thyristor (SCR) Gate-turn-off thyristor (GTO) Bidirectional triode thyristor (TRIAC) DIAC Light activated silicon-controlled rectifier (LASCR)

    10. Gate Turn Off thyristor (GTO). A GTO thyristor can be turned on by a single pulse of positive gate current like conventional thyristor It can be turned off by a pulse of negative gate current.

    11. The GTO has the following advantage over thyristor: Elimination of commutating components in forced commutation resulting in reduction in cost, weight and volume, Reduction in acoustic and electromagnetic noise due to the elimination of commutation chokes, Faster turn OFF permitting high switching frequency, Improved converters efficiency, and, It has more di/dt rating at turn ON.

    12. The thyristor has the following advantage over GTO. ON state voltage drop and associated losses are higher in GTO than thyristor, Triggering gate current required for GTOs is more than those of thyristor, Latching and holding current is more in GTO than those of thyristor, Gate drive circuit loss is more than those of thyristor, and, Its reverse voltage block capability is less than its forward blocking capability.

    13. Bi-Directional thyristor (TRIAC). TRIAC is used for the control of power in AC circuits. It is equivalent of two reverse parallel-connected SCRs with one common gate. Conduction can be achieved in either direction with an appropriate gate current. it is thus a bi-directional gate controlled thyristor with three terminals.

    14. DIAC DIAC is like a TRIAC without a gate terminal. DIAC conducts current in both directions depending on the voltage connected to its terminals. When the voltage between the two terminals greater than the break down voltage, the DIAC conducts and the current goes in the direction from the higher voltage point to the lower voltage one. The DIAC used in firing circuits of thyristors since its breakdown voltage used to determine the firing angle of the thyristor.

    15. Current and future power semiconductor devices development direction.

    16. Bipolar Junction Transistor (BJT)

    19. MOSFETs

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