Back Electro Motive Force Estimation Method for Cascade Proportional Integral Control in Permanent Magnet Synchronous Motors

A cascade proportional integral control method with back-electro motive force compensation has been widely used for permanent magnet synchronous motors. In the permanent magnet synchronous motor control, it is important to accurately know the back-electro motive force constant for torque generation as well as back-electro motive force compensation. In this study, a real-time back-electro motive force constant estimation algorithm is developed to improve the velocity tracking control performance. The proposed method consists of a proportional integral controller and a back-electro motive force constant estimator. The proportional integral controller is designed to reduce the velocity tracking error. The back-electro motive force constant estimator is designed to estimate the back-electro motive force constant. It was verified that the estimated back-electro motive force constant converges to the actual back-electro motive force constant. The estimated back-electro motive force constant is applied to the cascade proportional integral controller. To verify the effectiveness of the proposed method, the performance of the proposed method is validated experimentally.

Development and Application of Fuzzy Proportional-Integral Control Scheme in Pitch Angle Compensation Loop for Wind Turbines

Wind energy is regarded as one of the oldest energy sources and has played a significant role. As the nature of wind changes continuously, the generated power varies accordingly. Generation of the pitch angle of a wind turbine’s blades is controlled to prevent damage during high wind speed. This paper presents the development and application of a fuzzy proportional integral control scheme combined with traditional proportional control in the dynamic behavior of pitch angle-regulated wind turbine blades. The combined control regulates rotor speed and output power, allowing control of the power while maintaining the desired rotor speed and avoiding equipment overloads. The studied model is a large-scale wind farm of 120 MW in the Gulf El-Zayt region, Red Sea, Egypt. The control system validity is substantiated by studying different cases of wind speed function: ramp, step, random, and extreme wind speed. The results are compared with the traditional combined control. The model is simulated using MATLAB/SIMULINK software. The simulation results proved the effectiveness of fuzzy tuned PI against traditional PI control.

Generalised Proportional Integral Control for Magnetic Levitation Systems Using a Tangent Linearisation Approach

This paper applies a robust generalised proportional integral (GPI) controller to address the problems of stabilisation and position tracking in voltage-controlled magnetic levitation systems, with consideration of the system’s physical parameters, non-linearities and exogenous disturbance signals. The controller has been developed using as a basis a model of the tangent linearised system around an arbitrary unstable equilibrium point. Since the approximate linearised system is differentially flat, it is therefore controllable. This flatness gives the resulting linearised system a relevant cascade characteristic, thus allowing simplification of the control scheme design. The performance of the proposed GPI controller has been analysed by means of numerical simulations and compared with two controllers: (i) a standard proportional integral derivative (PID) control, and (ii) a previously designed exact feedforward-GPI controller. Simulation results show that the proposed GPI control has a better dynamic response than the other two controllers, along with a better performance in terms of the integral squared tracking error (ISE), the integral absolute tracking error (IAE), and the integral time absolute tracking error (ITAE). Finally, experimental results have been included to illustrate the effectiveness of the proposed controller in terms of position stabilisation and tracking performance when appreciable non-linearities and uncertainties exist in the underlying system. Comparative graphs and metrics have shown a superior performance of the proposed GPI scheme to control the magnetic levitation platform.

Design of Inverter Side of Modular Grid Simulator Based on Proportional integral-Quasi-proportional resonance Control

The tracking of a given voltage in the traditional double closed-loop proportional integral control in the current power grid simulator has problems such as static difference, delay and oscillation. It is proposed that the voltage outer loop and current inner loop of the inverter side of the power grid simulator adopt proportional integral and quasi-proportional resonance control respectively, and the topology of the inverter adopts a cascaded modular design to establish a single-phase inverter model. Compared with the traditional double closed-loop proportional-integral control, it is verified that the proportional-integral-quasi-proportional resonant controller can effectively improve the system’s ability to track the command voltage and the stability of the output voltage.