High-performance Ac Motor Control And Efficiency Improvement

AC motors are widely used in industry and life due to their reliability, ruggedness and relatively low cost. But the efficiency (the power factor) of traditional drive systems becomes lower in the case of light-load rate, and relatively, their reactive power increases, therefore a big energy-saved space exists for the AC drive. AC motors via variable frequency technology can operate in higher speed than the rated one;at this time, although prevention problems of over current and voltage seem important, but motor electrical loss will also be increased. These motivate people to investigate energy-saved technology.The dynamic performance of AC motor drives is enhanced by means of Vector Control Technology, but less attention to efficiency problems is paid till now. The international energy crisis awakes researchers not forgetting higher efficiency and loss- minimization as pursuing the higher dynamic performance.In this paper, the development of the AC motor drive and its control scheme are discussed at first, and analyzing the recent research situation of the frequently control strategy on AC drive system efficiency optimizing. Comparing with these control schemes, the advantages and disadvantages are pointed out.For the convenience of debugging and simulation, lessening the product designing time, an universal simulation platform of AC motors(including induction motors(IM) and permanent magnet synchronous motors(PMSM)) control system are established in the second chapter by programming Matlab/S-function and combining with some Matlab/Simulink blocks.On the basis of detailed analysis of the AC motors loss behavior;a relative accurate AC motor loss model taking the copper loss and iron loss into account is illustrated. And then, a loss- minimization efficiency optimization control strategy based on the loss model is given out. Base on the different operation point, the PMSM and IM speed controllers are designed.Finally, the paper gives the simulation experiment for the whole control system using the Matlab/Simulink software. Comparing with the traditional Vector Control strategy, the simulation results indicate that the new scheme can highly improve the efficiency of the AC drive system at the light load, so verify the effectiveness of the efficiency optimization scheme...