Dec 24 , 8: There is an initial controlled overshoot of about 80 V above the V DC bus voltage due to the higher impedance in the turn-off during desaturation protection. The main disadvantage of this method is the requirement to include two measurement devices in each inverter leg, along with any associated signal conditioning and isolation circuitry. The total delay to commencement of IGBT turn-off is seen to be around ns. Sign up using Email and Password.
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Generally speaking the motors are capable of absorbing very high current levels for relatively long periods milliseconds to seconds depending on motor size and type ; however the IGBTs—which make up the majority of industrial motor drive inverter stages—have short-circuit withstand times in the order ihbt microseconds.
Sign up using Email and Password. However, in many cases, either a leg shunt resistor or a phase shunt resistor will be present in the drive architecture for the purposes of the current control loop and motor overcurrent protection, and these can also be potentially utilized for IGBT overcurrent protection—provided that the response time of the signal conditioning is fast enough to protect the IGBT within the required short-circuit withstand time. Spehro Pefhany k 4 The curve doesn’t change off the edge of the sheet.
What happens off the edge of the sheet, though, is not clear to me. That would be an indication of something bad happening and it would be time to switch it off fast but not too fast, or that itself could cause damage.
They say that when this Desaturation occurs, there is an increase in the collector potential: Taking resistor technology beyond RoHS. Our header files are static or dynamic library 1.
IGBT and MOSFET Desaturation Protection
Equating complex number interms of the other 5. Along with the reaction time of the current sense circuitry or digital fast filters, the very short propagation delay of the ADuM in both instances is critical to achieving viable fast overcurrent protection using either of these methods.
IGBTs are not regarded as a fail-safe component and their failure can result in a dc bus capacitor explosion and complete drive failure. The curve does change off the edge of the sheet; put too much current through the device and it goes into an analog mode.
Does that mean the transistor go into Active region? In Figure 6, the delay between the hardware trip signal, the PWM output signal, and the actual gate-emitter waveform of the upper IGBT in one of the inverter legs is shown.
IGBT Overcurrent and Short-Circuit Protection in Industrial Motor Drives
This will not generally result in IGBT destruction, but it does increase power dissipation and compromises reliability. Additional flexibility in the control of switching rates can be provided by utilizing asymmetric gate resistors for turn-on and turn-off. This results in a rapid increase in the collector-emitter desaguration.
This article has outlined some approaches to handling this issue, and has presented experimental results that underline the value of robust isolated gate driver ICs such as the ADuM from Analog Devices. Hi Friends, Somehow, i do not understand this word completely.
There is also a strong dependency on the IGBT collector-emitter voltage, so the parallel trend toward higher dc bus voltage levels in industrial drives results in further reduction in short-circuit withstand times.
Power semiconductor device manufacturers are continually pushing the boundaries of conduction loss and dsaturation time improvements. The selection of ibt filter components are a trade-off between providing noise immunity and acting within the IGBT short-circuit withstand time. Which is the deal? Please Select a Language.
This can be alleviated by only adding shunt resistors in the positive and negative dc bus lines. I’ve heard IGBTs described as desaturating if too much current passes through them, particularly in the context of drivers with desat protection.
IGBT Overcurrent and Short-Circuit Protection in Industrial Motor Drives | Analog Devices
Figure 8 shows the collector-emitter voltage across the IGBT. Or is it just a way of saying “instantaneous overcurrent”? Analog Layout Finger Size 3.