Abstract: An IGBT physical model parameter extraction method includes obtaining an initial value and a transformation range of an IGBT physical model parameter; and correcting a model parameter by means of a correspondence between IGBT dynamic and static features and the IGBT physical model parameter and in combination with an experiment measurement result of the IGBT physical model parameter.

Abstract: A multi-frequency uniformization carrier wave slope random distribution pulse width modulation method, includes: (1) selecting a required random carrier wave sequence and a modulating wave, and after the two are compared, generating a switch device drive signal for pulse width modulation; (2) determining a multiple n of an equivalent carrier frequency f of the random carrier wave sequence, and selecting a main circuit topology; and (3) inputting the switch device drive signal generated in (1) into the main circuit topology of (2) to perform multi-frequency uniformization carrier wave slope random distribution pulse width modulation. The disclosure can improve a frequency domain distribution bandwidth of a harmonic wave without changing the mean and variance of a random carrier wave sequence, and realizes uniform distribution of carrier waves and multiple harmonic peaks near a doubled frequency of the carrier waves in a wider frequency domain.

Abstract: A hot repair material of refractory materials is provided and includes main materials and binding agents. The main materials include silicon carbide powders with six different particle sizes and a mass ratio according to particle sizes from large to small is 8:5:8:15:8:10. The binding agents include silicon nitride powders, a sodium silicate powder, an aluminum phosphate powder, a furfuryl alcohol, a silicone resin powder, a silica sol powder, an aluminum sol powder, a silicon oxide micronized powder, a vanadium oxide powder, a silicon powder, a borax and a rare earth oxide micronized powder, and a corresponding mass ratio is 20:10:4:1:5:1:1:2:0.5:0.5:0.5:0.5. The silicon carbide powders in the main materials have a good synergistic effect to improve strength of the repair material. The binding agents include low-, medium- and high-temperature binding agents for a full range of temperatures, so the repair material could gain strength continuously without a collapse temperature.