The difference between IGBT MOS and triodes
IGBTs are used in many devices, ranging from high-speed rail electric vehicles to small air conditioners and induction cookers. You may have three questions: What is an IGBT? What role does it play in the above devices? What's the difference between it and a seemingly tube?
For example, the internal model of an electric car is a battery plus a motor, and there needs to be a motor governor in the middle. The core component of the click governor is actually the switch, which generates a pwm wave through a high-speed switch. If you want to drive faster, the time for the switch to close will be longer; if you want to drive slower, then the time for the switch to be off will be longer. Another example is the frequency converter that is often promoted in air conditioner advertisements. The core principle is to put The 220-volt AC is rectified and filtered to become DC, and then a switch is used to control the pwm wave to adjust the speed of the compressor motor, thereby adjusting the cooling capacity.
In reality, we need the MCU to control the switch, so we will find a MOS tube to replace the switch. Normally, the MOS tube is enough for common switching scenarios, but there is no way to use the MOS tube in other scenarios. Switches, such as igbt application scenarios, have a common feature that the voltage is extremely high, which is the problem. For MOS tubes, the biggest problem is that they are not resistant to high voltage. Generally, 400V is the end, so in high-speed rail It is not suitable to use MOS tubes in high-voltage scenarios such as , electric vehicles, etc., and it is easy to burn out. So what components can withstand high voltage? The answer is triode, and its withstand voltage can be very high, even reaching the upper limit kilovolts, but this cannot be directly used in high-voltage circuits such as automobiles and high-speed rails. This is because the current of the triode cannot carry too much current, and the switching frequency limits its usage scenarios. Some people may Thinking that since MOS tubes and triodes have their own strengths, what would it be like to connect these two to the circuit?
Combining a triode and a MOS tube can withstand a high voltage and a large current, and the combination of a triode and a MOS tube is an IGBT.
At present, when selecting MOS tubes, triodes, and IGBTs in the circuit, it needs to be selected according to the actual application scenario. None of these three components can meet the conditions of current, withstand voltage, and switching frequency at the same time. It is used according to the actual situation, and silicon carbide, a new material other than these three, can indeed meet these three conditions.