| Cycloconverter-fed drive is generally used for very large horsepower, low-speed applications, such as rolling mills, winding motors, marine propeller, cement mixer, etc. Cycloconverter, as the main equipment of this system, is popular for its efficiency, simpleness and high reliability. The studies of it are in beginning step at home. This paper analyzed and designed the multi-phase cycloconverter system which aimed at multi-phase synchronous motor, emulated and put on trial for the general character and especial problems of the cycloconverter. After analyzed the work theory of the cycloconverter in detail, several woke mode was given. Compared with their strongpoint and shortcoming, the mode of logic no-circulation flow was adopted to this system. After analyzed the math model of the multi-phase cycloconverter, the simulation wave of output voltage and output current was given and the harmonic was analyzed. In order to control the load current accurately, the voltage-character cycloconverter was changed to current-character cycloconverter. The current regulator was designed here and the control strategy of combination of detached PI regulator and intelligent integral. Based on the theory of cosine crossing point, the combination of three-sector approximate cosine crossing point and regulation sampling to compute trigger angle on line was given. And the current make-and break compensation based on fuzzy control was given. Compared with the several digital projects and structures, a digital scheme of a DSP plus CPLD was adopted in this paper. DSP was in charge of completing the interface of men and machine, the decision of zero-current, trigger angle computing on line, D/A output display. The formation and distribution and output of trigger pulse was completed by CPLD. Finally, the control technology of this paper was approved by the results of experiments.
|
PDF Full Text Request