Abstract: With the purpose of reducing costs and improving the properties of the closed-loop speed control system, presents a new dual-loop control strategy based on the thyristor converter.The added active current closed loop on the basis of feedback loop speed control, by frequency, voltage coordinated control to achieve double-loop speed control.Analysis of motor active current characteristics according to the experimental data, obtained by fitting the slip and active current relationship.By bivariate alternating conversion frequency characteristics, in making full use of the motor overload conditions, determine speed program.Simulations with Matlab and experiment results with ARM, are presented to verify the feasibility and effectiveness of alternating conversion frequency dual-loop speed control program.

Key words: thyristor, converter, active current, dual-loop control