Research Of Dead-time Compensation Technology Based On Predictive Current Control For PMSM

Predictive current control is one of the heat research contents in recent years. Similarly to the tradit ional contro l schemes, proper dead t ime is needed in order to prevent the short circuit between the upper and lower bridges of the inverter, besides, time delays also exist during the switching on and off of power tubes, thus, mismatches must exist between the ideal drive signals and the practical signals input to power tubes. This mismatch will lead to decrease of fundamental waveform amplitude and distortions on phase current, thus the total harmonic distortion increases, torque ripples occur as well, this becomes more obvious when under low speed and light load. In order to eliminate the effect caused by dead zone and further perfect the system performance, dead zone must be restrained.In this paper, the dead zone effects of direct predict ive contro l and PWM predictive control are analyzed, similarit ies and differences of condit ions with and without modulat ion modules are analyzed. A self-adaptive dead zone co mpensat ion method based on PWM predict ive contro l is proposed, a co mparative study of the proposed method and convent ional t ime co mpensatio n method is conducted on Simulink, results show that the proposed method and time compensat ion method both will restrain the dead zone effect of PWM predictive contro l, according to online speed variation scheme, when speed changes, the proposed method can achieve self-adapt ive dead zone co mpensat ion and with adaptivit y but the time compensat ion method cannot. Then combined with the direct contro l characterist ic, the proposed co mpensat ion method is extended to direct predictive contro l, Simulat ion results indicate that it also will restrain the dead zone effect o f direct predict ive contro l.Finally, the experiment verificat ion is conducted reciprocal test-bench plat form, after realizat ion of two co mpensat ion methods, the proposed one and time co mpensat ion, comparative study o f the two is conducted. Experiment results show that the proposed method and t ime co mpensat ion method can both well restrain dead zone effect within PWM predict ive contro l and the proposed method can achieve self-adapt ive dead zone compensat ion.