The Theory Analysis And Compensation Research On The Dead-Time Effects In PWM Voltage Source Inverter

Inverter technology with the development of modern control theory, electronic technology of electric power, electronic computer, microelectronics, etc. has already entered a new era, its application has" entered a new climax correspondingly too. PWM control technology applies to ac machine driver, regulated power supply and Uninterruptible Power System (UPS), etc. In the electric drive system, the advantage of using PWM is outstanding day by day. But the effect question of dead time still can't be neglected in PWM voltage source inverters. The modern electric power electronic device is being developed to high frequency, dead-time effects are more and more serious to affect the output current and output voltage of the inverter. Dead time effects issue arouse the attention of the masses of scholars, to compensate the influences of dead time becomes a piece of important subject to improve the waveforms of inverter.This paper has recommended inverter technology and PWM control technology at first, has analyzed the necessity to input dead time in the inverter. At PWM variable-frequency regulating speed system analyses the influence of dead time effects of the inverter for example.This paper analyzes the effects of dead time from the harmonic waves. Th'e existence of dead time results in a reduction in the fundamental component of inverter voltage and the addition of unwanted low order harmonics and increases the harmonic distortion of the inverter output voltage. The distorted voltage may give rise to serious problems such as current waveform distortion and increased torque ripples, and unstable operation. So it is necessary to compensate the dead time effects for the high performance especially such as vector control of ac motor.This paper has proposed the method that predictive control is used to compensate the dead time effects of ac machine driver. The algorithm of predictive control can be implemented by only the DSP. The simulation responses and experimental results are also presented to show the validity of the analysis proposed in the paper. The researches of this paper have the value for improving the performance of the ac machine driver and the further study of the dead time effects.