Circuits can be designed to meet many of the automotive, military, and avionic standards including iso76372. This reference design details a gate driver circuit for a threephase inverter. The driver circuit td350 which performs intelligent control of igbt transistors in order to control overvoltages has been described in detail. Application of igbt drive and protection circuit, library. It is these types of failure that industry demands protection against especially as power levels approach 100 kw and beyond and systems become expensive so manufacturers of igbt drivers such as power integrations have builtin innovative and reliable protection regimes into their products that address these circumstances to safeguard the. In this technique, the voltage remains regulated and the cost of this circuit is very less when compared with other methods.
Any and all events that could cause a jump in dc bus voltage could lead to a dc link overvoltage fault event. Its intentionally installed backward with the notshown body diode cathode toward the right side of the circuit. Recovering when the fault disappears takes about 400s. The circuit has a few components, it is very easy to build and will protect your electric equipment againg overvoltages. Troubleshooting vfd problems overvoltage fault voltage. Application note an 7002 connection of gate drivers to. The fault protection methods used in igbt converters are different from their gate turnoff thyristor gto counterparts. Chapter 5 protection circuit design 58 2 overvoltage suppression methods several methods for suppressing the turnoff surge voltage, the cause for overvoltage, are listed below. Fundamentals of mosfet and igbt gate driver circuits laszlobalogh abstract the main purpose of this application report is to demonstrate a systematic approach to design high performance gate drive circuits for high speed switching applications. It is important to realize this fact to aid in troubleshooting. A necessary companion for discrete power mosfets and igbts as well as digital microcontrollers, dsps and fpgs or analog controllers in any switchedmode power converter, stdrive gate drivers generate the necessary voltage and current level required to accurately and efficiently activate the power stage in industrial, consumer, computer. Protection measures against short circuit conditions if the calculated junction temperature exceeds the maximum rating of the devices, a short circuit detection and protection circuit for every igbt is proposed the same way as they are used in vsis, e. Providing reliable and efficient operation of electronic devices often requires introducing of an additional protection from electric circuit parasitic components during the design stage. The protection circuitry comprises of comparators 2, voltage references, capacitors, and resistors.
Another form of zener diode circuit is an overvoltage protection circuit. High power igbt modules employ hybrid ic gate drives including protection circuits. Efficient control of igbt transistor as part of overvoltage. Igbtdriver circuit for desaturated turnoff with high desaturation level kr101407245b1 en 20061121. With vce voltage detecting and active voltage clamping, the driver circuit can accurately detect the short circuit of igbt, and can effectively restrain the overvoltage in shortcircuit shut off. Overvoltage protection circuit, usb positive, with. Dec, 2017 anyway, a summary of the way this protection circuit works, i am sure you know already, is that basically the shunt nfet effectively transfers the transient overvoltage to the current clamp nfet, so that the load led driver can survive and avoid the overvoltage. The purple block shows the igbt bridge dcac inverter for load powering. But, certainly, this type of circuit has drawbacks. By implementing shortcircuit protection using a resistor network, the r vce resistors scale down the collector voltage and limit the current flowing from the collector to the gatedriver sense input. The igbt can change its switching properties through the gate drive, so designing a proper.
System for fault protection in igbt us20080212247a1 en 20061121. Active clamping with igbt is basically similar to active clamping as realized by an internal zdiode between drain and gate in some selfprotecting mosfet devices. The units include dc link voltage sensing, diagnostic leds, overvoltage protection, current sensing, and heatsink temperature sensing capability. This requires the input circuit to be blocked by the external circuit to prevent the igbt from continuously passing large current pulses. Zener diode d8 connect parallel with d7 and act as the protection or prevent of reverse polarity of voltage and current going through output. Designing a simple overvoltage protection circuit using. Overcurrent and short circuit detection and turnoff in a very short time period are becoming ever more important as the short circuit withstand time of igbt decreases down to 1. It is placed across the power supply output terminals. Insulated gate bipolar transistor fault protection system. This discrete circuit can be constructed in the secondary side of the opto. Thanks to the integrated pmos fet, no external device is necessary, reducing the system cost and the pcb area of the application board. Shutting down due to an overvoltage takes about 100s. Overvoltage limitation for power transistors powerguru. The driver circuit td350which performs intelligent control of igbt transistors in order to control overvoltages has been described in detail.
Circuits can be designed to meet many of the automotive, military, and avionic standards including iso. Design for reinforced isolation threephase inverter with current, voltage, and temp protection. Because of the much lower driver impedance, active clamping with igbts usually involves the. The total current and didt seen by the external power circuit is the sum of currents and didts through each igbt chip. Efficient control of igbt transistor as part of overvoltage protection. An overvoltage protection circuit is a circuit which protects electronics from excess voltage, which could potentially damage or destroy electronic components. Protection strategies for igbt current source inverters. Higher gain results in higher short circuit current in the igbt, so it is clear that the lowergain igbt has a lower short circuit level. Application note an 7002 connection of gate drivers to igbt. Overvoltage protection elimination of the turnoff overvoltage spikes. Igbt overcurrent and shortcircuit protection in industrial. These voltages can add to the normal onstate gate voltage, causing a surge. The primary function of the gate drive circuit is to convert logic level control. With vce voltage detecting and active voltage clamping, the driver circuit can accurately detect the short circuit of igbt, and can effectively restrain the overvoltage in short circuit shut off.
Fundamentals of mosfet and igbt gate driver circuits. Essential for the design of the driver is to limit the voltage at the igbt and handling. Switching voltage transient protection schemes for high. Use a film capacitor in the snubber circuit, place it as close as possible to the igbt in order to bypass high frequency surge currents. The driver integrated circuit alone is not sufficient to completely protect the igbt, and an auxiliary protection circuit must be added to cut off the input drive signal.
This accentuates the importance of the gate driver circuit and its overcurrent detection and protection features. Power consumption of this circuit under normal conditions is about 0. Method 3 another protection method is to use an igbt desaturation circuit. Sep 18, 2016 over voltage protection how crowbar circuit works. How not to destroy an igbt new chipset mops up a significant number of passive and active components to improve reliability and decrease size. In a gto converter, a crowbar is used for protection and as a result there is no current limiting. Ncp361 is able to disconnect the system from its output pin in case wrong vbus operating conditions are detected. This overvoltage protection or crowbar protection circuit is used where we need protection against high voltage surge. So, insulated gate bipolar transistor igbt becomes the designers choice. Connection between gate driver and igbt module the gate driver must be located very close to the igbt module to minimize stray inductance between the gate driver and igbt module. This can sometimes make the drive circuitry more complex and you lose the isolation. Jun 10, 2018 a desaturation protection circuit is usually adopted to sense the vce, and the igbt needs to be shut down when vce exceeds the preset ratio voltage typically somewhere between 7 volts to 10 volts. Control the surge voltage by adding a protection circuit snubber circuit to the igbt.
Inpaq offers solutions that are all designed to make electronic products to work smoothly and effectively. Gate driver configuration and short circuit protection for. Applied power systems ap1491 gate driver is a fully integrated igbt driver for threephase bridge or full bridge circuit applications. A necessary companion for discrete power mosfets and igbts as well as digital microcontrollers, dsps and fpgs or analog controllers in any switchedmode power converter, stdrive gate drivers generate the necessary voltage and current level required to accurately and efficiently activate the power stage in industrial, consumer, computer and automotive applications. Another method is to reduce the turnoff impedance of the gate driver circuit for a period of time after completion of the. Sfi has the largest production capability of mlvs in the world market and offers other product lines of the over voltage protection components, to supply customer with all kind of circuit protection devices for their. The crowbar circuit must be mounted between power supply and the protected device. Pdf fast overcurrent protection of high power igbt modules.
The green block identifies the brakechopper circuit for dc bus overvoltage. When rg increases, it will increase the turnon and turnoff time of the igbt, and increase the power consumption of turnon and turnoff, but at the same time, it can reduce the reverse recovery overvoltage of the freewheeling diode and reduce the influence of emi. The igbt provides both power transistor and power mosfet benefits. When the voltage is less than the preset level, the base terminal of the q2 is high and as it is a pnp transistor, it turns off. In the event of a short circuit at the inverter output, overcurrent detection with. The crowbar protection circuit is a failsafe protection circuit. Jun 10, 2018 drive vfd overvoltage protection for common low hp drives is based on the measured voltage on the dc bus of the unit and not the input ac voltage. A new technical article, titled efficient control of igbt transistor as part of overvoltage protection, has been published in magazine international journal of electrical engineering and computing. Igbt overcurrent and shortcircuit protection in industrial motor. The paper analyzes the phenomena of appearance of overvoltage during the switchingoff of the igbt transistor which arecaused by the presence of parasitic inductance in the switching circuit. Since the igbt turns off very quickly, if the overcurrent is shut off using an ordinary drive signal, the collectoremitter voltage will rise due to the inductive kick, and. In most of the igbt gate drive design, conventionally it embeds the overvoltage protection circuit, however, the problem of shortcircuit would still. In case you want additional capacitance, the transil diode is bringing more than necessary.
Nus2045mn, nus3045mn overvoltage protection ic with. A gate drive circuit is an integrated circuit that accepts a low power input from a controller ic and produces the appropriate voltage and current for a power semiconductor switch. Implement gate drivers for 3level npc2 modules with. Mains overvoltage transient protector using linearly. Insulated gate bipolar transistor failure analysis in. Zener overvoltage protection circuit pros and cons. Drive vfd overvoltage protection for common low hp drives is based on the measured voltage on the dc bus of the unit and not the input ac voltage. In the circuit in the past, because the existence of stray inductance on the major loop is turnoffed excessive electric current and will be produced too high shutoff overvoltage during short circuit protection, be easy to exceed the safety operation area of igbt, thereby cause the overvoltage of igbt to lose efficacy.
Pdf efficient control of igbt transistor as part of. Igbt overcurrent and short circuit protection in industrial motor drive sep 22, 2017. A desaturation protection circuit is usually adopted to sense the vce, and the igbt needs to be shut down when vce exceeds the preset ratio voltage typically somewhere between 7 volts to 10 volts. The driver circuit td350 which performs intelligent. Industrial motor drive reliability is strongly linked to the igbt protection circuits. Each individual chip switched its share of the load current at a didt that is determined by the gate drive circuit. Igbt short circuit withstand time and its transconductance or gain and igbt chip heat capacity. This zener diode circuit uses the zener diode in a slightly different way, detecting the breakdown current through the diode once a certain voltage has been reached. The ucc21520 has many features to design a reliable three phase inverter. Overvoltage protection of high power igbts in wind power. Visit technical article abstract a marketwide trend in industrial motor drives is an increasing demand for higher efficiency coupled with increased reliability and robustness. Igbt overcurrent and short circuit protection in industrial.
An advantageous solution, even for highpower igbt modules, is to mount the gate driver onto the igbt module directly. Cn202888814u igbt short circuit protection soft turnoff. Gate drive circuit an overview sciencedirect topics. Anyway, a summary of the way this protection circuit works, i am sure you know already, is that basically the shunt nfet effectively transfers the transient overvoltage to the current clamp nfet, so that the load led driver can survive and avoid the overvoltage. Ovp protection using zener diodes is the easiest and simple process to protect devices from overvoltage. This paper presents the insulated gate bipolar transistor igbt device failure analysis in overvoltage condition, which is a normal phenomenon occurring in a poor power quality utility system. Hybrid circuits optimize gate drive and protect high power igbt. Igbt overcurrent and shortcircuit protection in industrial motor drives dara osullivan applications engineer, analog devices, inc. Us5559656a igbt switching voltage transient protection. The ix6611 gate driver also implements monitoring and protection features such as undervoltage and overvoltage lockout uvloovlo, thermal shutdown, and external igbt overcurrent and overvoltage protection. Consult the igbt manufacturers application note for guidance on selecting the proper models of these devices.
Failure mechanisms of insulated gate bipolar transistors. The crowbar circuit mechanism contains, crowbar device and sensing circuit monitoring circuit. This article has outlined some approaches to handling this issue, and. Choosing the appropriate gate series resistance rg is important for igbt drive. Overvoltage protection circuit diagram working of overvoltage protection circuit.
Control the surge voltage with an additional protection circuit snubber circuit to the igbt. The situation is at its worst when a short circuit current is. Gate drive circuits can also provide fault protection of igbt in the circuit. In this project, we will build a simple, yet effective, overvoltage protection circuit using a fuse and a zener diode, as the protecting elements, that will work for electronics that.
This discrete circuit can be constructed in the secondary side of the opto gate driver. And, when q2 is in off condition the base terminal of q1 will be low and it allows the current to flow through it. Analog devices family of high voltage surge stoppers, overvoltage protection, overcurrent protection, and circuit breaker ics offer solid frontend protection in small, low power, easy to design solutions that increase system reliability. A gate driver sometimes includes also the protection circuit of the. The gate drive circuit comprises of three ucc21520 devices, which are dual igbt gate drivers. Mosfetigbt for determining the power loss in a driver while driving a power mosfet, the best way is to refer to the gate charge g vs. On the other hand, silicon carbide mosfet works in the linear region during normal operation, acting like a resistor.
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