The main advantages of using IGBTs over other types of transistors are relatively fast switching speeds, a low driving power and a simple drive circuit due to the input MOS gate structure. It also offers a very low on-state voltage drop, due to conductivity modulation, and has superior on-state current density. For example, in the case of a variable frequency driver (VFD), an IGBT will switch the current on and off so rapidly that less voltage will be channeled to the motor, helping to create a pulse-width modulation (PWM) wave to control the speed of the motor.
IGBT technology is available in a variety of voltage classes, current ratings, and topologies (e.g. half bridge, full bridge). They can be used in wide range of applications, and are an especially a good choice for moderate speed and high voltage applications. The growing need to minimize power system size and weight is increasing the design of IGBT modules that use the latest advances of IGBT technology (topologies, materials, etc.), and, moreover, the use of the latest advances in power semiconductor packaging. Here are some different IGBT solutions for three different applications:
Industrial Motor Drives
A good option to regulate the efficiency, speed, position, and torque of motors (e.g. pumps, fans, etc.) is the use of semiconductor devices such as IGBTs that can help to switch the current flow to motors with minimal switching-time or conduction-period losses.
One of the challenges for motor drives is the limitation of switching speed due to the inherent limitation of the motor insulation system. Most motor manufacturers typically recommend not exceeding a dv/dt limit of approximately 5 kV/ÎĽs under worst-case conditions for 400 V motors to avoid voltage spikes and rise times that can lead to arcing and eventually to coil-insulation failure.
Infineonâ€™s 1,200 V TRENCHSTOPâ„˘ IGBT7 is specially optimized for industrial drives applications. It is based on micro-pattern trenches (MPT), and is characterized by implementing parallel trench cells separated by sub-micron mesas. IGBT7 offers the ability to vary the dv/dt by adjusting the value of the gate resistor (RG) (Figure 2). Infineonâ€™s technology also allows operation at a temperature of 175Â°C under overload conditions that could result in higher power density, but such high temperatures might result in higher heatsink temperatures.