Intelligent modulation method for carrier wave frequency self-adapting float in high voltage frequency conversion

Abstract

The invention relates to a intelligence modulator method of self-adapted fluctuation of the carrier wave frequency in the high-pressured frequency conversion, its characteristic lies, uses the Intel ASM96 software, the chip uses 80C196MC of Inter Corporation, the procedure workouts by assembly language, its method is: chooses the saddle-shaped wave as the modulating wave, the reference carrier frequency of 5 hertz - 60 hertz divides the current modulation wave frequency to obtain the carrier ratio of current correspondence modulation wave frequency; the carrier ratio is a reference carrier ratio, its value divides 3 to obtain the contained pulse integer in the half-wave; the pulse integer after taking the integer rides the reference carrier ratio then obtained one is 3 integral multiple carrier ratios again. The invention can do harmonic suppression and auto-adapted fluctuation of the carrier frequency in the three-phase symmetrical high-pressured frequency conversion.

Description

technical field [0001] The invention relates to an intelligent modulation method for adaptive floating of carrier frequency in high-voltage frequency conversion, and belongs to the technical field of high-voltage frequency converters. Background technique [0002] AC inverters have been widely used in many fields of production and life, but relatively mature inverter products at home and abroad are low-voltage products, which cannot meet the requirements of high-voltage loads. , and the high-voltage inverter required by high-voltage motors has not yet been particularly mature products. [0003] The cascaded multi-level high-voltage inverter is the most advantageous one among the many high-voltage frequency conversion main circuit solutions. Currently, the cascaded multi-level high-voltage inverters on the market in my country are mostly voltage type, and the output current waveform THD of such inverters It is very small, but the harmonic content of the output voltage is stil...

AI Technical Summary

Problems solved by technology

[0007] The disadvantage of this modulation method is that when the output frequency of the inverter circuit is very low, the carrier frequency is also very low. When the carrier frequency is too low, the harmonics brought by the modulation cannot be eliminated.

[0010] The disadvantage of this modulation method is: when the signal wave frequency is low, the carrier is relatively large, the number of pulses in one cycle is large, the positive and negative half-cycle pulses are asymmetrical, and the front and rear 1 / 4 cycle pulses are asymmetrical in a half cycle. The adverse effects are small, and the PWM waveform is close to a sine wave

[0013] The disadvantage of segmental synchronous modulation is that when the carrier ratio is changed, oscillation, voltage mutation and harmonic surge will occur, which will cause the motor to generate large pulsating torque and strong noise, which will affect the operation of the motor. come to harm, affect the service life of the motor, and also consume energy

Images