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Analysis of IGBT in Rail Transit and Hybrid Vehicle Application and Selection
Date:2014-4-12 Hit:1145

The rail traffic referred to in this paper is mainly used for electric traction trains and subways, and its high-power AC drive electric locomotive interior has two important power modules, namely the main traction converter and auxiliary converter. The main traction converter provides the power for the traction locomotive, the highest power, the largest voltage, the most harsh working conditions. Auxiliary converter for other non-powered current power supply, such as air conditioning, lights, backup power, voltage, power is relatively low, the working conditions are relatively good. }

The main traction converter requires 3.3 kV or 6.5 kV high voltage module, the auxiliary converter required voltage is relatively low, 1.7 kV module can be met. They need to use traction-level IGBT module, because the locomotive working environment is very bad. Traction IGBTs are the most demanding IGBTs in the field of electronic applications, demanding reliability and product lifecycle requirements.

Traction-level IGBT power up to 10 million watts, each IGBT to withstand the maximum voltage up to 6.5 kV, the nominal current up to 600 An. The working environment of the traction-grade high-voltage high-power IGBT is harsh and the load changes drastically, which has great influence on the life of the IGBT module. This requires the use of specific technology to improve the temperature cycle life and power cycle life of the device.

General industrial IGBT power module operating temperature of 125 ℃, but Infineon (Infineon) IHM / IHV-B series traction-level IGBT power module operating temperature than the common industrial-grade power module operating temperature higher than 25 ℃, to 150 ° C. Increasing the temperature of 25 ° C has two advantages for the IGBT: First, the output power of the IGBT module is increased, which is beneficial to increase the density of the output power of the module, thus making the design of the whole converter more compact. Second, to improve the working temperature of the traction-level IGBT to enhance the power cycle capacity, thereby improving the reliability of the module and working life.

"Increasing the junction temperature is a means of increasing the available power of the IGBT, and it is the result of the enhanced IGBT module packaging technology." Vivek Mahajan, director of industrial power marketing at Infineon Technologies and the diversified electronics market division, points out that the IGBT's output current Mainly subject to junction temperature limits, the chip temperature limits its power load. If you can increase the junction temperature means that the IGBT can output more current. There are two ways to improve the junction temperature: First, reduce the IGBT saturation voltage, reduce the loss of IGBT; another means is to improve the module's wire bonding process, enhance its reliability and power exchange capacity. Increasing the junction temperature of the IGBT allows the customer to achieve greater power consumption and lower losses. The radiator temperature and module housing temperature are also reduced, allowing the module to output more current while the IGBT's reliability is significantly longer Module life. "

The power of the hybrid is from the internal combustion engine and the motor, and part of the driving force is obtained from the internal combustion engine which is stable at the optimum working point and the other part is obtained from the motor. If the actual power required is smaller than the supply capacity of the internal combustion engine, it is charged with excess power and stored in the battery through the generator. If the required power is greater than the function of the internal combustion engine, the motor can drive the locomotive together with the internal combustion engine. Hybrid locomotives use this "hybrid doubles" approach to learn from each other, so that the internal combustion engine to obtain the best energy efficiency.

The key components of a hybrid are generator and motor drive, and the key to generator and motor drive is the IGBT module. As the hybrid vehicle operating environment is slightly better than rail transit, so you can choose a slightly lower level of vehicle-level IGBT module. For example, Infineon's PrimePACK fourth-generation IGBT, the maximum junction temperature of 175 ℃. Practical application, the position of the IGBT can be closer to the substrate screw fixed point method to effectively reduce the thermal resistance between the substrate and the heat sink effect, the internal stray inductance and similar products can be reduced by about 60%.

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