Modeling and control of a high-quality electro-hydraulic actuator driven via an induction motor under intelligent indirect vector control

Abstract

Due to its excellent energy efficiency and broad speed range, the variable-speed electro-hydraulic drive is an appealing driving principle in many contemporary industrial applications. A primary control of linear motion is via a variable-speed electric motor driving a hydraulic actuator via a constant displacement pump. One of the most commonly used controllers for the speed control of induction motors is the Proportional Integral (PI) type. However, the traditional PI controller has some disadvantages, such as the high starting overshoot, sensitivity to controller gains, and sluggish response due to sudden disturbance. An intelligent controller based on PI Fuzzy logic set theory is introduced to the electro-hydraulic system to overcome these defects. This paper presents a study on the speed control of an indirectly controlled vector-controlled induction motor driving an electro-hydraulic actuator. Various speed control techniques like voltage-frequency control, sinusoidal pulse width modulation PI control, indirect field control, and fuzzy logic PI control were applied in the electro-hydraulic system and simulated by Matlab/Simulink environment for performance analysis and comparison. The results prove that the indirect field-oriented control technique with PI fuzzy logic control provides better speed control of the induction motor, especially with high dynamic disturbances, by reducing the steady state error to (0.024), overshooting to (0.2%) and Settling time to (0.3s). This, in turn, will improve the performance of the proposed electro-hydraulic system.

Keywords

• electro-hydraulic actuator
• induction motor
• constant displacement pump
• pi fuzzy logic
• indirect vector control