Presentation on theme: "Power Semiconductor Systems I"— Presentation transcript:
1Power Semiconductor Systems I Author: Ales HavelPhone number: 4287Headquarters: E227Web page:Power Semiconductor Systems I
2Presentation contents Power semiconductor devicesPower diodeThyristorsGTO thyristorIGCT thyristorMCTPower transistorsBipolar transistor (BJT)MOSFETIGBTMain types of converters
3Diode structure and symbol Power diodeSingle P-N junction creates a diode that has two terminals:an anode (A) and a cathode (K).Diode structure and symbol
4Power diodeSteady State V-I Characteristic of a Diode
5Power diode Dynamic parameters Dynamic parameters relate to fast transition from ON to OFF statesNot 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.
6Power diodeTransient V-I Characteristic of a Diode
7Power diode Main requirements: reverse voltage Ur as high as possible voltage drop UF as low as possibleturn-off speed as high as possibleQrr (reverse recovery charge) as low as possible
8ThyristorThyristor (SCR – Semiconductor Controlled Rectifier) is a controlled semiconductor device of 4-layer PNPN structure with 3 PN junctions.Thyristor schematic symbol and structure
9ThyristorSteady-State V-I Characteristic of a Thyristor
10ThyristorTransient V-I Characteristics of a Thyristor
11Thyristor Switching conditions: To turn-on: To turn-off: UA = UD > 0 (forward blocking state)Bring sufficiently high current IG into the gateTo turn-off:The forward current has to stop flowingA control electrode cannot effect thyristor turn-offThe IL current (latching current – min. value to turn on)The IH current (holding current – min. value to stay open)
12GTO thyristorGTO 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
13MCT thyristorMOS 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 another is responsible for turn-off.
14TransistorsThe npn BJT is a three junction device that requires a continuous current flowing into the base region to supply enough charges to allow the junctions to conduct current.Because the MOSFET and the IGBT are voltage controlled devices, they only require voltage on the gate to maintain conduction through the device.The IGBT has one junction more than the MOSFET, and this junction allows higher blocking voltage and conductivity modulation, as described below, during conduction. This additional junction in the IGBT does limit switching frequency however.
15BJT transistorA 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
16BJT transistor Main principle of the BJT transistor Collector Base EmitterSwitching the BJT transistor
18MOSFET transistorA Power MOSFET is a specific type of metal oxide semiconductor field-effect transistor that has been designed to handle large amounts of power.N-ChannelP-ChannelDepletion modeEnhancement mode
20MOSFET transistor Static characteristic MOSFET Linear area Saturation area
21Symbol and equivalent circuit model of an IGBT IGBT transistorThe 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
26IGBTThe 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.