Optimizing PWM modulation method capable of restraining harmonic wave

Abstract

The invention discloses a modulating method for the optimized PWM of restrainable harmonic waves, which utilizes the combination of space voltage vectors (SVPWM) to realize the elimination of 'm' ('m' equals to 6 multiplied 'j' and plus or minus1; 'j' equals to 1, 2, ellipsis) times of harmonic wave, wherein, 'm' refers to a certain odd number which is not divisible by 3 and comprises 5, 7, 11, 13, etc. The method of the invention is characterized in that the method can be realized by programming, thereby not only solving the problem of calculated amount or look-up table memory capacity existing in a SHEPWM method, using the combined voltage vector to approach the circular trace of a flux linkage, and helping to reduce torque pulsation, but also fulfilling the task of selectively eliminating the harmonic wave.

Description

An optimized PWM modulation method capable of suppressing harmonics technical field The invention relates to a PWM modulation method, which is used to realize the control of a three-phase voltage type inverter to drive a three-phase AC motor to run. Background technique Three-phase voltage source inverters can be used in AC motor drives and inverter power supplies, and the corresponding pulse width modulation (Pulse width modulation, PWM) technology, especially the voltage space vector PWM (space vector pulse width modulation, SVPWM) technology has gradually become the most widely used One of the modulation techniques. The basic principle of SVPWM technology is: use the 8 switch states of the inverter in the main circuit shown in Figure 1 to synthesize the space voltage vector and send out PWM waves. In Figure 1, if 1 represents the conduction state of the switching device of the upper bridge arm of each phase of the inverter, and 0 represents the conduction state of the...

AI Technical Summary

Problems solved by technology

The feature of this method is that it can be realized by programming. It not only solves the problem of the calculation amount of the SHEPWM method or the storage amount of the look-up table, but also uses the synthesized voltage vector to approximate the circular trajectory of the flux linkage, which helps to reduce the torque ripple. And complete the task of selecting harmonic cancellation

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