Study On Dual-PWM Vector Control Variable-Frequency System

Based on the research on the theory and technology of dual-PWM variable frequency, a design of dual-PWM variable frequency system which has high power factor rectifier and vector control is proposed. This kind of device not only actively eliminate ac-side harmonic pollution of inverter, raise ac-side power factor, economize energy resources, but also greatly promote dynamic characteristic of AC variable speed drive system.The author lays a strong emphasis on study of PWM rectifier. The basic structure, operation principle and mathematical mode of it are studied in this paper. After analyzing and comparing two kinds of current control methods of three-phase VSR: indirect current control and direct current control, the author employs the latter as main control scheme, which is to control the phase and amplitude of ac-side current directly, by using dual closed-loop control scheme, through sampling currents of phase a and b and converting them by 3s/2r to get active component and reactive component of ac-side current.In study of PWM inverter, several control methods and the mathematic models of AC motor are analyzed first. Next the basic principle and performance of vector control are explained. Finally, discuss the PWM inverter mathematic model and obtain the conclusion that PWM rectifier analytic method can be used in PWM inverter.Based on the above-all study, experimental device has been designed, including IPM and TMS320F240 as main apparatus. Control firmware has been realized with...