4 Concrete examples of drive circuits

For inverter circuits and the like, it is necessary to electrically isolate the IGBT from the control circuit. An example of a drive circuit using this principle, is shown below. Fig. 7-5 shows an example of a drive circuit using a high speed opto-coupler. By using the opto-coupler, the input signal and the module are isolated from each other. Also, since the opto-coupler does not limit the output pulse width, it is suitable for changing pulse widths or PWM controllers, to wide ranges. It is...

Chapter

Parallel This chapter explains the factors that inhibit current sharing and the notes when IGBT is connected in parallel. When connecting IGBT modules in parallel, it is necessary to properly manage the elements' characteristics. Otherwise, a current sharing imbalance may occur depend on the characteristics distribution between the parallel connected modules.

Gate Drive circuit Design

Drive 3. Setting 4. Concrete examples of drive 5. Drive circuit setting and actual This section explains the drive circuit design. In order to maximize the performance of an IGBT, it is important to properly set the drive circuit constants.

IGBT terms

Definition explanation (See specifications for test conditions) Maximum collector-emitter voltage with gate-emitter shorted Maximum gate-emitter voltage with collector-emitter shorted Maximum forward DC current of internal diode Maximum forward pulse current of internal diode Maximum power dissipation per element Chip temperature during continuous operation Temperature range for storage or transportation, when there is no electrical load on the terminals Value of joule energy (value of...

Q Drive circuit setting and actual implementation

5.1 Opto-coupler noise ruggedness As IGBTs are high speed switching elements, it is necessary to select a opto-coupler for drive circuit that has a high noise ruggedness (e.g. HCPL4504). Also, to prevent malfunctions, make sure that the wiring from different sides doesn't cross. Furthermore, in order to make full use of the IGBT's a high speed switching capabilities, we recommend using a opto-coupler with a short signal transmission delay. 5.2 Wiring between drive circuit and IGBT If the wiring...

Q Drive current

Since an IGBT has a MOS gate structure, to charge and discharge this gate when switching, it is necessary to make gate current (drive current) flow. Fig. 7-1 shows the gate charge (dynamic input) characteristics. These gate charge dynamic input characteristics show the electric load necessary to drive the IGBT and are used to calculate values like average drive voltage and the driving electric power. Fig. 7-2 shows the circuit schematic as well as the voltage and current waveforms. In...

Q Parallel connection

In high capacity inverters and other equipment that needs to control large currents, it may be necessary to connect IGBT modules in parallel. When connected in parallel, it is important that the circuit design allows for an equal flow of current to each of the modules. If the current is not balanced among the IGBTs, a higher current may build up in just one device and destroy it. The electrical characteristics of the module as well as the wiring design, change the balance of the current between...

Q Selecting heat sinks

Most power diodes, IGBTs, transistors and other power devices are designed to be insulated between electrodes and mounting bases. This type of module can be mounted and wired compactly in a variety of equipment, because several devices can be mounted in a single heat sink. However, in order to ensure safe operation, the power loss (heat) generated by each module must be dissipated efficiently. This is why heat sink selections is very important. The basic of heat sink selection will be...

Q Storage and transportation notes

1) The IGBT modules should be stored at an ambient temperature of 5 to 35 C and humidity of 45 -75 . If the storage area is very dry, a humidifier may be required. In such a case, use only deionized water or boiled water, since the chlorine in tap water may corrode the module terminals. 2) Avoid exposure to corrosive gases and dust. 3) Rapid temperature changes may cause condensation on the module surface. Therefore, store modules in a place with minimal temperature changes. 4) During storage,...

Structure and Features

Gate controlled overcurrent 4. Overcurrent limiting 5. Module 6. Circuit configuration of IGBT Power converters, such as variable-speed motor drives and uninterruptible power supplies for computers, were revolutionized with the introduction of bipolar power transistor modules and power MOSFETs. The demand for compact, lightweight, and efficient power converters has consequently also promoted the rapid development of these switching devices. Bipolar transistor modules...

T Mounting notes

When mounting IGBT modules in designated equipment, note the following 1) When mounting an IGBT module on a heat sink, first apply a thermal compound to the module's base and then secure it properly to the heat sink by tightening the specified screws using the recommended torque. Use a heat sink with a mounting surface finished to a roughness of 10 m or less and a flatness of 100 m or less between screw mounting pitches. For more details, refer to Chapter 6 of this manual. 2) Avoid wiring...

T Designing heat sinks

As the maximum allowable junction temperature (Tj) of an IGBT module is fixed, an appropriate heat sink must be selected to keep it at or below this value. When designing appropriate cooling, first calculate the loss of a single IGBT module, then based on that loss, select a heat sink that will keep the Tj within the required limits. If the IGBT module is not sufficiently cooled the temperature may exceed Tj (max.) during operation and destroy the module. For more information on IGBT power loss...

Q IGBT characteristics

This section illustrates the characteristics of the new 5th- generation IGBT modules, using the U series 6MBI100UB-120 (1200V, 100A) as an example. While the IGBT is on, the collector-emitter voltage (VCE) changes in accordance with the collector current (IC), gate voltage (VGE), and temperature (Tj). The VCE represents a collector-emitter voltage drop in the ON state, and is used to calculate the power dissipation loss of the IGBT. The smaller the VCE value, the lower the power dissipation...

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 Switching Waveforms

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

What Causes Short 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...