Selective harmonic elimination pulse width modulation control method of eliminating dead zone effect and device thereof

Abstract

The invention discloses a selective harmonic elimination pulse width modulation control method of eliminating dead zone effect and a device thereof, which are used for a neutral point clamped NPC multi-level converter. The selective harmonic elimination pulse width modulation control method comprises steps that the current voltage closed-loop control of the NPC multi-level converter is carried out, and a voltage modulation ratio and a real-time phase are calculated in a real-time manner; a preset switching angle storage table is queried according to the voltage modulation ratio, and a standard switching angle corresponding to the voltage modulation ratio is acquired; the standard switching angle is modified according to the output current direction, the delayed- conduction arc value, and the early-shut off arc value of the NPC multi-level converter, and the dead zone effect of the standard switching angle is eliminated, and then the modified standard switching angle is acquired; based on the modified standard switching angle, an angle interval, in which is disposed the real-time phase, is determined, and a driving pulse having a dead zone corresponding to a real-time angle is acquired according to the angle interval and a preset corresponding relation table, and then the NPC multi-level converter is driven. The influences of the dead zone effect on the driving pulse of the converter are eliminated, and the harmonic level of the converter is optimized.

Description

technical field [0001] The invention relates to the technical field of converter control, in particular to a specific harmonic elimination pulse width modulation control method and a device thereof for eliminating the dead zone effect. Background technique [0002] Diode clamped (NPC, Neutral point clamped) three-level converters are very suitable for medium-voltage high-power industrial converter drives (such as locomotive traction, offshore wind power, metallurgical rolling mills, mine hoists, ship propellers, etc.), Combined with existing commercial high-voltage and high-power semiconductor devices (such as IGBT, IGCT, IEGT, etc.), the high withstand voltage and strong overcurrent performance of the converter can be realized. The three-phase topology of NPC three-level converter is as follows: figure 1 shown, where S 1 , S 2 , S 3 , S 4 It is a fully controlled switching device, and each switching device is anti-parallel with a freewheeling diode (D 1 ~D 4 ), D 5 ...

AI Technical Summary

Problems solved by technology

The dead time will affect the obtained standard switching angle, which will cause the output voltage to deviate, cause output voltage distortion, increase the harmonic content of output voltage and current, and cause impact on the load or power supply network, such as causing the torque of the motor to occur violently. Fluctuation or even damage, total harmonic distortion (Total Harmonic Distortion, THD) of output current does not meet international or domestic grid-connected standards, etc., and the impact of wide dead zone is even worse

Images