Application of universal optical fiber isolation driver in high-power IGBT

O Introduction

　　Since the advent of MOSFET and IGBT, voltage-controlled power electronic devices, especially IGBT, are experiencing a rapid development process. The voltage of IGBT single module devices is getting higher and higher, and the current is getting larger and larger. At the same time, the supporting driving devices have also developed rapidly. As the application fields of devices become wider and wider, the conversion power of power equipment becomes larger and larger, and the electromagnetic T interference also increases accordingly. For this reason, it is necessary to improve the anti-interference ability of the control board and improve the drive withstand voltage level. Therefore, the use of optical fiber has become inevitable.

1 Several ICBT driving methods

　　IGBTs with different power levels have different driving requirements. Table 1 gives a comparison of several currently commonly used driving methods.

　　As can be seen from Table 1, only transformers or optical fiber isolation can be used in high-power power conversion devices, among which optical fiber isolation is the best choice.

2 Types of fiber optic transceivers

　　At present, most fiber optic transceivers use several product models of Agilen. The details are as listed in Table 2 (the data listed in the table are all for use conditions of 0 to 70°C, unless otherwise noted).

　　Under normal circumstances, HFBR-1522 and HFBR-2522 are commonly used. Their circuits are shown in Figure 1 and Figure 2, and the circuit connections are shown in Figure 3. In high-power power conversion equipment, the signal transmission rate of 1MBd between the control board and the high-power module driver board can meet the requirements, and the distance of 45m is also sufficient. In actual use, the length of the optical fiber can be selected according to requirements.

3 Specific application of optical fiber transmission in drive circuits

　　We take Concept's dedicated high-voltage IGBT drive board (ItVI) ISD418F2-FZ2400R17KF6 as an example to describe its specific application. The driving object of the driver board is 2400V/1700AIGBT. This combination has all the functions of IPM. The specific circuit block diagram is shown in Figure 4 below.

Figure 4 Typical applications of optical fiber transmission in drive circuits

4 Conclusion

　　By introducing the optical fiber transmission mode, the control signal is transmitted from the control board to the drive board through the optical fiber, and the status signal is transmitted from the drive board to the control board, completely eliminating the interference problem, achieving both drive control and monitoring the working status of the IGBT , improving the reliability of work.