Power Semiconductor Systems I Author: Ales Havel E-mail: ales.havel@vsb.cz Phone: 5937 Office: EA333 Web: http://homen.vsb.cz/~hav278/ Power Semiconductor Systems I

Contents Power semiconductor devices Main types of converters Power diode Thyristors GTO thyristor IGCT thyristor MCT Power transistors Bipolar transistor (BJT) MOSFET IGBT Main types of converters

Power diode Single P-N junction creates a diode that has two terminals: an anode (A) and a cathode (K). Diode structure and symbol

Power diode Steady State V-I Characteristic of a Diode

Power diode Dynamic parameters Dynamic parameters relate to fast transition from ON to OFF states Not only speed of transition between the two states is important, but also changes in the diode voltage and current during the transition should be taken into account.

Power diode Transient V-I Characteristic of a Diode

Power diode Main requirements: reverse voltage Ur as high as possible voltage drop UF as low as possible turn-off speed as high as possible Qrr (reverse recovery charge) as low as possible

Thyristor Thyristor (SCR – Semiconductor Controlled Rectifier) is a controlled semiconductor device of 4-layer PNPN structure with 3 PN junctions. Thyristor schematic symbol and structure

Thyristor Steady-State V-I Characteristic of a Thyristor

Thyristor Transient V-I Characteristics of a Thyristor

Thyristor Switching conditions: To turn-on: To turn-off: UA = UD > 0 (forward blocking state) Bring sufficiently high current IG into the gate To turn-off: The forward current has to stop flowing A control electrode cannot effect thyristor turn-off The IL current (latching current – min. value to turn on) The IH current (holding current – min. value to stay open)

GTO thyristor GTO thyristor (Gate Turn-Off thyristor) is a semiconductor device built on the same principle as traditional thyristor. The difference is in the case that the GTO could be turned of by the negative gate current. GTO Thyristor schematic symbol and structure

MCT thyristor MOS Controlled Thyristor (MCT) is voltage controlled fully controllable thyristor. The MCT is similar in operation with GTO thyristor, but it has voltage controlled insulated gate. It has two MOSFETs in its equivalent circuit. One is responsible for turn-on and the other is responsible for turn-off.

Transistors

BJT transistor A Bipolar (Junction) Transistor (BJT) is a three-terminal electronic device constructed of doped semiconductor material and may be used in amplifying or switching applications. Bipolar transistors are so named because their operation involves both electrons and holes. The BJT has three terminals, corresponding to the three layers of semiconductor – an emitter, a base, and a collector. Schematic mark

BJT transistor Collector Base Emitter Main principle of the BJT transistor Collector Base Emitter Switching the BJT transistor

BJT transistor Static characteristics Output Transfer Input Reverse

MOSFET transistor A Power MOSFET is a specific type of metal oxide semiconductor field-effect transistor that has been designed to handle large amounts of power. N-Channel P-Channel Depletion mode Enhancement mode

MOSFET transistor Switching MOSFET very high

MOSFET transistor Static characteristics MOSFET Linear area Saturation area

Symbol and equivalent circuit model of an IGBT IGBT transistor The Insulated Gate Bipolar Transistor (IGBT) is a minority-carrier device with high input impedance and large bipolar current- carrying capability. Symbol and equivalent circuit model of an IGBT

IGBT transistor Switching IGBT

IGBT transistor Absolute maximum ratings

IGBT transistor Electrical characteristics

IGBT transistor Thermal characteristic

IGBT transistor The IGBT is suitable for many applications in power electronics, especially in Pulse Width Modulated (PWM) servo and three-phase drives requiring high dynamic range control and low noise. It also can be used in Uninterruptible Power Supplies (UPS), Switched-Mode Power Supplies (SMPS), and other power circuits requiring high switching repetition rates. IGBT improves dynamic performance and efficiency and reduced the level of audible noise. It is equally suitable in resonant-mode converter circuits. Optimized IGBT is available for both low conduction losses and low switching losses.

Comparison of power semiconductor devices

Power converters A power semiconductor converter is an electrical device for converting electrical energy.

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