IGBT, as the core component of electrical control of new-energy electric vehicle, motor controller of G-series high-speed train and high-voltage frequency converter, which is known as the “CPU” in the electric power industry. No matter consumer electronics, home appliances, or aircraft, ships, rail transit, smart grid and other strategic industries, all need the participation of IGBT modules. High-accuracy silver electrode NTC thermistor chip produced by EXSENSE Electronics Technology Co., Ltd., due to its characteristics of high sensitivity, rapid response, which is used in temperature monitoring and temperature control of the IGBT module.
Because IGBT has the advantages of high input impedance of Metal Oxide-Semiconductor Field Effect Transistor (MOSFET) and the low on voltage drop of Bipolar Junction Transistor (BJT), it is considered a high-speed switch that controls high voltage on-off with low voltage. The speed of IGBT switch is very fast, which can up to microseconds (us), and the driving power is small, usually around 15V control voltage can be driven.
At present, the development level of high-voltage IGBT is (600 to 1200) A/6500V, its operating frequency is (18-20) kHz, and with the development of voltage level is increasing. In other words, the voltage on-off over kilo-volts can be controlled with a voltage of 15V, and the on-off frequency can reach more than 10KHz. This feature makes IGBT widely used in motor drive, frequency modulation, inverter circuit, switch control, etc., and becomes the leading role in industrial production, transportation, electric motor of rail transportation.
Because of its unique characteristics, IGBT is often used in inverter circuit and frequency changer circuit.
First, Pulse Width Modulation (PWM) frequency changer circuit
PWM pulse width modulation is by changing the pulse width to control the output voltage, by changing the cycle to control its output frequency. The waveform of Silent Pulse width Modulation (SPWM) is the PWM waveform where the pulse width changes according to the sine law. This pulse wave is generated by transistors such as IGBT and MOS tubes.
Second, multi-level inverter, frequency changer circuit
By arranging IGBT in various forms of topological structure, direct current can be converted into alternating current, and the frequency of alternating current can be controlled and adjustable. Two – level and three – level circuits are the most common types in inverter circuit. High voltage inverter commonly used three-level scheme, IGBT has three states:
1, output is positive (P)
2, output is 0 (not on)
3, output is negative (N)
The silver electrode NTC thermistor chip for IGBT, which accuracy can up to ±0.5%, ±1%, ±2%, and ±3%, with an operating temperature range of -50℃ to 200℃. NTC chip has characteristics of good heat cycle resistance and fast response time, so that the IGBT module still can maintain good stability and reliability at high temperature.