Research On Random SVPWM Three-level Inverter Based On Markov Chain

Compared with the two-level inverter, multi-level inverter is more suitable for high voltage, large volumes of occasions, has been more widely used. In a variety of control strategies of multi-level inverter, space vector modulation SVPWM algorithm has a modulation ratio to optimize the output voltage waveform and easy digital implementation, the bus voltage utilization advantages, become the focus of attention. Mathematical model and control strategy of this paper, three-level SVPWM inverter, SVPWM modulation method based on the Markov chain random cycle reduces the propagation of electromagnetic interference in the inverter, and the simulation results show.In this paper the analysis of several types of three-level inverter topology, described the operation mechanism of the three-level inverter; a comprehensive and systematic study on the three-level inverter SVPWM modulation means, focus on how to achieve three-level inverter SVPWM modulation. Elaborated on the basis of random PWM relevant principles.The working principle of the Markov process and Markov chain research, carried out a detailed analysis of the two-state Markov chain; principles of analysis and simulation results is verified by comparing the distribution for the random number. On this basis, the text inverter based on two-state Markov chain random cycle SVPWM modulation method. This modulation method makes a random cycle near the desired cycle to a more uniform distribution of dispersed originally focused on the switching frequency is an integer multiple of prominent harmonic energy, inverter power spectrum more continuous, so as to achieve to reduce the inverter harmonic electromagnetic interference conduction.Finally, in order to verify the validity of this modulation method to construct a simulation model based on Markov chain of three-level inverter random SVPWM control system. Simulation results verify the effectiveness of this method.