The controller's energy comes from a high-voltage battery pack (high-voltage DC, typically 300-400 V). Inside the motor controller, through control chips, drive circuits, and IGBTs, different control algorithms are used for different motors to convert DC power into AC power, which is then output to the motor to generate torque.
The system block diagram is as follows:
What is the function of IGBTs?
IGBTs are mainly used for energy conversion and transmission, and are widely used in new energy vehicles, smart grids, aerospace and communications.
IGBT stands for Insulated Gate Bipolar Transistor, a semiconductor widely used in new energy vehicles. What is a semiconductor? Metals have good electrical conductivity and are called conductors; plastics, ceramics, and wood have poor electrical conductivity and are called insulators. Between conductors and insulators, semiconductors possess electrical conductivity.
An IGBT is a semiconductor whose conductivity is controlled by a control circuit. For example, if the control circuit indicates "on," the IGBT is a conductor, and current flows through it; if the control circuit indicates "off," the IGBT is an insulator, and current is blocked. IGBTs can easily convert input DC current to AC current, simply by using pulse width modulation (PWM) to convert it to frequency. Charging stations draw standard 220V AC current from the grid, while Tesla electric vehicles require DC charging. This necessitates the IGBT converting AC to DC and boosting the voltage to the 400V required by the electric vehicle to charge its 7000 18650 batteries. The performance of the IGBT directly determines the charging efficiency and speed of the electric vehicle.
When an IGBT is turned on, it can withstand currents ranging from tens to hundreds of amperes, while when turned off, it can withstand voltages ranging from hundreds to thousands of volts. Furthermore, IGBTs can achieve extremely high switching speeds under high current and voltage conditions, reaching up to 10,000 switching operations per second. Therefore, the quality of the IGBT directly determines the acceleration speed, top speed, energy consumption, ability to accelerate in seconds, smooth gear changes, and stable stopping of an electric vehicle—all performance depends on the IGBT.
IGBTs are core components for energy conversion and transmission. Other electric vehicles, such as high-speed trains, also extensively use IGBTs. A single high-speed train requires nearly 200 IGBT chips. IGBTs are expensive; a single imported Mitsubishi IGBT chip is very costly, and the IGBT control chip alone costs around 150,000 yuan. In the Tesla Model 3, which uses approximately 150 IGBT chips, this is the most expensive component besides the battery, accounting for over 20% of the total cost.
The IGBT market is basically monopolized by foreign companies such as Infineon and Mitsubishi. China has its own intellectual property rights, and BYD is one of the better companies in this field.
