| Under the background of energy saving and environmental protection,conventional hydraulic system drove by asynchronous motor is gradually being reduced use.At the same time,a new hydraulic system drove by PMSM is receiving more attention for the advantages of low energy consumption,high efficiency,less oil spill and low noise.This new hydraulic system is an important development direction.Due to the later start of the study,China is in the rising stage in this field.As target of developing PMSM drives used for hydraulic press,this paper carrys out following studies.Firstly,the paper introduces the source of the subject and the research status of servo hydraulic technology,and analyses the work principle of the new hydraulic system drove by PMSM.Besides,the paper compares FOC and DTC of PMSM.Based on the current development trend of AC servo technology at home and abroad,the paper select FOC as the control strategy.Secondly,by analyzing the mathematical model in three different coordinate systems,the paper investigates the algorithms of FOC,and introduces the working process based on control block diagram.After analysing the transfer function of the current loop and the speed loop,the design method of PI regulators is given,and verified by simulation.In order to improve the performance of the current loop,the paper proposes an offline parameters identification method of PMSM,and introduces the implementing measures.Thirdly,the paper introduces the hardware scheme based on the design block diagram,the main program and the main interrupt routine based on flow diagram.To ensure the implementation of the FOC,the paper designs the current sampling program,the resolver demodulation program and the PI regulator program and so on.Finally,the effectiveness of the algorithm is verified by simulation with MATLA/Simulink.Besides,the experiments show that the proposed control system is available,reasonable and the PMSM drives has an excellent performance and can meet the user's demands. |
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