With global warming, "low carbon" has become a hot word in today's society, "low carbon economy", "low carbon lifestyle", and even the hottest real estate industry has recently launched "low carbon real estate". In the final analysis, the essence of "low carbon" is to reduce energy consumption and carbon dioxide emissions. According to statistics, 60% ~ 70% of electric energy is used in low energy consumption system, and the vast majority is consumed in power conversion and power drive. Power devices play a key role in improving the efficiency of power utilization, so how to reduce the energy consumption of power devices has become an important global issue.
In aerospace electronic products, the power consumption, volume and weight of electronic equipment are more important than ground equipment, sometimes even the main indicators to measure the product.
Silicon carbide (SIC) power devices are resistant to high temperature, radiation, high breakdown voltage and operating frequency. They are suitable for working in harsh conditions. Compared with traditional silicon (SI) power devices, silicon carbide power devices can reduce the power consumption by half, thus greatly reducing the heat consumption, volume and weight of switching power supply, motor driver and other circuits.
Although silicon carbide power devices have been promoted to the market in recent years, they have been used in hybrid electric vehicles and electric vehicles. Because of the incomparable advantages of ordinary silicon power devices in many aspects, it is of great practical significance to promote silicon carbide power devices to aerospace electronic products.
Application of silicon carbide power devices in aerospace electronic products
According to the above analysis, combined with the actual Aerospace military industry, the application of silicon carbide power devices in aerospace electronic products is mainly concentrated in the following fields.
1. Switching power supply on missile / rocket and solar power system on satellite / spacecraft
In switching power supply system, diodes are generally used as rectifiers, freewheeling protection, etc. When used as rectifier, the reverse recovery time of rectifier diode is too long, which leads to the decrease of conversion efficiency and the increase of heating. Although the use of Schottky diodes can solve the problem of reverse recovery, the breakdown voltage of conventional silicon (SI) Schottky diodes is very low (usually less than 200 V), coupled with the derating design, it is not suitable for high voltage applications. The Schottky diode made of silicon carbide (SIC) can withstand voltage up to 1200V, and the reverse recovery current is almost negligible, so it can greatly reduce the switching loss of the device. At the same time, it can also simplify the protection circuit in the switching power supply circuit. Figure 2 shows the simplification of boost topology switching power supply provided by Cree company after using silicon carbide Schottky diode.
Figure 2 using SiC diode to simplify the design of boost switching power supply
2. The driver of Brushless DC motor or electric steering gear on missile / arrow
At present, the power of Brushless DC motor or electric steering gear used on missile / rocket is increasing day by day. For the driver of Brushless DC motor or electric steering gear, due to the limitation of battery voltage on missile / rocket, only by increasing the current can sufficient power be output. The larger current brings more dissipation power and heat, which will increase the volume and weight of the actuator, and virtually increase the invalid load of the projectile / arrow and shorten the range.
Silicon carbide Schottky diode has the characteristics of high temperature resistance and zero reverse recovery current, which can greatly improve the performance of motor driver, reduce the dissipation power, volume and weight, and improve the reliability of products.
In addition, when the fabrication process of SiC MOSFET is mature, the volume and weight of motor driver can be further reduced if it can replace the current switching power devices because of its excellent high temperature performance.
3. Application of SiC MESFET in spaceborne / airborne radar transmitter
SiC MESFET is mainly used in microwave field, which is very suitable for radar transmitter; it can significantly improve the output power and power density of radar transmitter, improve the working frequency and bandwidth, improve the environmental temperature adaptability of radar transmitter, and improve the anti radiation ability.
Compared with conventional silicon (SI) power devices, silicon carbide (SIC) power devices have obvious advantages. Although the market promotion of silicon carbide power devices is still in the initial stage, its application prospect is broad and its development speed is rapid. Under the promotion of "low carbon" economic concept, its development pace will be accelerated. Aerospace electronic products have strict requirements on their weight, volume, power consumption and radiation resistance. The emergence and further promotion of silicon carbide power devices will have a profound impact on the development of aerospace electronic products in the future.
Source: power electronics technology and Applications