Q Parallel connections 21 Wiring

The ideal parallel connection wiring is both uniform and short, but when seen from the point of view of equipment mass production, it is often to implement this fully. Therefore, it is necessary to design a layout as close to the ideal as possible. For this purpose, several basic points of caution are illustrated below. When connecting IGBT modules in parallel, due to the gate circuit's wiring inductance and the IGBT's input capacitance, as the gate voltage rises a parasitic oscillation may...

Q Factors that inhibit current sharing 11 Onstate current imbalance

An on-state current imbalance may be caused by the following two factors (2) Main circuit wiring resistance distribution 1) Current imbalance caused by VCE(sat) distribution As shown in Fig. 8-1, a difference in the output characteristics of two IGBT modules connected in parallel can cause a current imbalance. u The output characteristics of Q1 and Q2 shown in Fig. 8-1, can be approximated 4s as follows Based on the above, if the ICtotal ( Ici+Ic2) collector current is made to flow through the...

Module structures

Igbt Wire Terminal

Fig. 1-6 and Fig. 1-7 show typical IGBT module structures. The module integrated with a terminal block shown in Fig. 1-6 has a case and external electrode terminals molded into a single unit to reduce the number of parts required and cut the internal wiring inductance. In addition, the use of a direct copper bonding DCB substrate makes for a high-reliability product that combines low thermal resistance and high transverse breaking strength. The wire terminal connection structure module shown in...

Q Heat sink mounting precautions 31 Heat sink mounting

Since thermal resistance varies according to an IGBT's mounting position, pay attention to the following points When mounting only one IGBT module, position it in the exact center of the heat sink in order to minimize thermal resistance. When mounting several IGBT modules, determine the individual position on the heat sink according to the amount of heat that each module generates. Allow more room for modules that generate more heat. The mounting surface of the heat sink should be finished to a...

Q Static electricity countermeasures

If an IGBT is subjected to a VGES that exceeds this rated value, then there is a danger that the module might be destroyed. Therefore, ensure that the voltage between the gate and emitter is never greater than the maximum allowable value. When an IGBT is installed and voltage is applied between the collector and emitter while the gate emitter connection is open as shown in Fig. 3-1, depending on changes in the electric potential of the collector, the current i...

Q Setting deadtime

Dead Time For Igbt

For inverter circuits and the like, it is necessary to set an on-off timing delay dead time in order to prevent short circuits. During the dead time, both the upper and lower arms are in the off state. Basically, the dead time see Fig. 7-3 needs to be set longer than the IGBT switching time toff max. . Accordingly, if RG is increased, switching time also becomes longer, so it would be necessary to lengthen dead time as well. Also, it is necessary to consider other drive conditions as well as...

Fuji

Table 4-1 Causes of device failure modes Table 4-1 Causes of device failure modes Short circuit destruction of one element Confirm waveform locus and device ruggedness match during an arm short circuit. Check for circuit malfunction. Apply the above. Insufficient gate reverse bias. Gate wiring too long Check for accidental turn-on caused by dv dt. Insufficient gate reverse bias. Date time setting error Check that elements toff and deadtime match. Miswiring, abnormal wire contact, or load short...

Q Overvoltage protection

Igbt Protection Overvoltage

2.1 Overvoltage causes and their suppression 1 Overvoltage causes Due to the high switching speed of IGBTs, at turn-off or during FWD reverse recovery, the current change rate di dt is very high. Therefore the circuit wiring inductance to the module can cause a high turn-off surge voltage V L di dt . At an example, using the IGBT's waveform at turn-off we will introduce the causes and methods of their suppression, as well as illustrate a concrete example of a circuit using an IGBT and FWD...

Q IGBT drive conditions and main characteristics

IGBT drive conditions and main characteristics are shown below. An IGBT's main characteristics change according to the values of VGE and RG, so it is important to use settings appropriate for the intended use of the equipment in which it will be installed. Table 7-1 IGBT drive conditions and main characteristics. Table 7-1 IGBT drive conditions and main characteristics. Non latch-up circuit is built into N series IGBT. Short circuit withstand capability depends on current limiting circuit...

Snubber Circuit Design For Igbt

Igbt Testing Waveform

The effect on turn-off surge voltage is moderate. As opposed to the RC snubber circuit, a snubber diode has been added. This allows the snubber's resistance to increase and consequently avoids the IGBT load conditions at turn-on problem. Since the power dissipation loss of this circuit primarily caused by the snubber's resistance is much greater than that of a discharge suppressing snubber circuit, it is not considered suitable for high frequency switching applications. The power dissipation...

Cooling Design

Selecting heat 3. Heat sink mounting This section explains the cooling design. For safe IGBT operation, the junction temperature Tj must never exceed Tj max . Therefore, it is necessary to have a cooling design capable of keeping the junction temperature below Tj max , even during overload conditions.

IGBT test procedures

Igbt Module Testing

An IGBT module that has been found to be faulty can be checked by testing it on a transistor characteristics measuring device called a transistor curve tracer CT . 1 Leakage current between gate and emitter, and threshold voltage between gate and emitter 2 Short circuit, breakdown voltage, open circuit between collector and emitter Short gate and emitter. If a CT is not available, other test equipment, such as a Volt-ohm multi-meter that is capable of measuring voltage resistance and so forth...

Q Structure and features

Fig. 1-1 compares the basic structure of an IGBT and a power MOSFET. The IGBT is characterized by a p - -layer added to the drain side of the power MOSFET structure. It is this p - -layer that enables the various IGBT features explained in this manual Drain D 1 MOSFET basic structure Collector C 2 IGBT basic structure Fig. 1-1 Basic structure of MOSFET and IGBT As shown in Fig. 1-2, the ideal IGBT equivalent circuit is a monolithic Bi-MOS transistor in which a pnp bipolar transistor and a power...

Q Power dissipation loss calculation 11 Types of power loss

An IGBT module consists of IGBT chips and FWD chips. The sum of the power losses from these sections equals the total power loss for the module. Power loss can be classified as either on-state loss or switching loss. A diagram of the power loss factors is shown as follows. Total power loss of IGBT module Ptotal Switching reverse recovery loss Prr The on-state power loss from the IGBT and FWD sections can be calculated using the output characteristics, while switching loss can be calculated from...

Q Short circuit overcurrent protection 11 Short circuit withstand capability

Igbt Protection Circuit

In the event of a short circuit, first the IGBT's collector current will rise, once it has reached a certain level, the C-E voltage will spike. Depending on the device's characteristics, during the short-circuit, the collector current can be kept at or below a certain level, however the IGBT will still continue to be subjected to a heavy load high voltage and high current . Therefore, this condition must be removed as soon as possible. The amount of time allowed between the start of a short...

Content

Gate controlled overcurrent 4. Overcurrent limiting 5. Module 6. Circuit configuration of IGBT Chapter 2 Technical Terms and Characteristics 1. IGBT 2. IGBT Chapter 3 IGBT Module Selection and Application 1. Selection of IGBT module 2. Static electricity 3. Designing protection 4. Designing heat 5. Designing drive 6. Parallel 7. Mounting 8. Storage and transportation 3-6 9. Additional 2. IGBT test 3. Typical trouble and 1. Short circuit overcurrent 1. Power...