The application of compound proportional resonant control strategy in multiple PV inverters system

2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840098
Author(s):  
Yuan Li ◽  
Huifang Shen ◽  
Chao Xiong ◽  
Yaofei Han ◽  
Guofeng He
Keyword(s):  
Control Strategy ◽  
Closed Loop ◽  
Control Strategies ◽  
Integrated Control ◽  
Reference Signal ◽  
Loop Model ◽  
Harmonic Compensation ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Set Up

In order to eliminate the effect on the grid current caused by the background harmonic voltage and the reference signal on the grid connected multi-inverter, this paper adopts the double closed-loop feed-forward control strategy. This strategy is based on the inductor voltage and the grid-connected current, and the integrated control strategy of quasi-proportional resonance loop parallel to a specific harmonic compensation loop. Based on the closed-loop model of multiple inverters, the change curves of the transfer function of the two control strategies are compared with the feed-forward control and the composite proportional resonance. The two corresponding control methods are used to analyze the current quality of the multi-inverter impact. Finally, the MATLAB/Simulink simulation model is set up to verify the proposed control strategies. The simulation results show that the proposed method can achieve better tracking of the sinusoidal command signal at the fundamental frequency, and enhance the anti-interference ability of the system at the 3rd, 5th, and 7th harmonic frequency.

Experimental Evaluation of a Control Strategy for Real-Time Optimization of Low Temperature PEM Fuel Cell Stack

2009 ◽  
Author(s):  
Panini Kolavennu ◽  
Susanta K. Das ◽  
K. Joel Berry
Keyword(s):  
Fuel Cell ◽  
Real Time ◽  
Control Strategy ◽  
Pem Fuel Cell ◽  
Effective Control ◽  
Feed Forward ◽  
Fuel Cell Stack ◽  
Feed Forward Control ◽  
Time Optimization ◽  
Real Time Optimization

A robust control strategy which ensures optimum performance is crucial to proton exchange membrane (PEM) fuel cell development. In a PEM fuel cell stack, the primary control variables are the reactant’s stochiometric ratio, membrane’s relative humidity and operating pressure of the anode and cathode. In this study, a 5 kW (25-cell) PEM fuel cell stack is experimentally evaluated under various operating conditions. Using the extensive experimental data of voltage-current characteristics, a feed forward control strategy based on a 3D surface map of cathode pressure, current density and membrane humidity at different operating voltages is developed. The effectiveness of the feed forward control strategy is tested on the Green-light testing facility. To reduce the dependence on predetermined system parameters, real-time optimization based on extremum seeking algorithm is proposed to control the air flow rate into the cathode of the PEM fuel cell stack. The quantitative results obtained from the experiments show good potential towards achieving effective control of PEM fuel cell stack.

Vibration Control for Parallel Manipulator Based on the Feed Forward Control Strategy

2013 ◽  
Author(s):  
Ming Li ◽  
Huapeng Wu ◽  
Heikki Handroos ◽  
Marco Ceccarelli ◽  
Giuseppe Carbone
Keyword(s):  
Control System ◽  
Dynamic Model ◽  
Control Strategy ◽  
Parallel Manipulator ◽  
External Disturbance ◽  
Machining Process ◽  
End Effector ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Model Based

Due to the high stiffness, high dynamic performance, the parallel manipulator presents great advantages in the industrial manufacture. However in the machining process, the external low frequency disturbance, e.g. the varying cutting force, has a significant effect on the control system of parallel manipulator, which presents a chatter phenomenon on the end-effector of manipulator. In this paper, a feed forward control strategy is proposed to eliminate the effect of the random external disturbance on the control system of parallel manipulator. By applying the external disturbance force on the inverse dynamic model, the compensation torque is calculated and fed forward into the manipulator driving joints to cancel out the effect of the disturbance acting on the manipulator end-effector. The key issue herein is to be able to establish the accurate dynamic model for the parallel manipulator. Furthermore, in order to guarantee the position precision of the manipulator, a feed forward model-based control strategy combined with the feedback loop PV (position and velocity) control has been developed based on the reference trajectory, which could relatively simplify the highly nonlinear control system of the parallel manipulator and obtain a stable tracking error model. The whole research has been carried out on a parallel manipulator named CaPaMan which has been built in the laboratory of robotics and mechatronics in university of Cassino and South Latium. The results show that the chatter phenomenon could be utterly depressed by the force compensation from the feed forward path of the external disturbance; meanwhile the model-based controller can guarantee the trajectory tracking accuracy within a stable error by choosing the suitable PV gains.

scholarly journals Power Quality Improvement through a UPQC and a Resonant Observer-Based MIMO Control Strategy

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6938
Author(s):  
Holman Bueno-Contreras ◽  
Germán Andrés Ramos ◽  
Ramon Costa-Castelló
Keyword(s):  
Quality Improvement ◽  
Power Quality ◽  
Control Strategy ◽  
Closed Loop ◽  
Mimo Systems ◽  
Control Strategies ◽  
Harmonic Distortion ◽  
Phase System ◽  
Coupling Effects ◽  
Power Quality Improvement

Performance degradation is, in general, regarded as a power quality problem. One solution to recover grid performance is through the application of a unified power quality conditioner (UPQC). Although these devices are multi-input/multi-output (MIMO) systems, the most common control strategies consist of two decoupled controllers, which neglect the coupling effects and add uncertainty to the system. For this reason, this paper proposes a multivariable resonant observer-based control strategy of a UPQC system. This method includes all significant coupling effects between this system and the grid. This strategy results in a stability-based compensator, which differs from recently proposed strategies that are based on signal calculation and cannot assure closed-loop stability. In addition, this paper introduces a simplified controller tuning strategy based on optimal conventional methods without losing closed-loop performance. It implies that the controller can be easily tuned, despite the complexity of the MIMO dynamic model. The UPQC with the resonant observer is verified on an experimental setup for a single-phase system, obtaining three relevant results for power quality improvement: (1) harmonics compensation tested with a total harmonic distortion limit of 5%; (2) sags and swells mitigation; and (3) power factor correction, achieving a unitary value on the grid side.

scholarly journals A Grid Voltage Feed-forward Control Strategy Based on The Virtual Impedance

2017 ◽  
Vol 139 ◽  
pp. 00137
Author(s):  
Chu Wang ◽  
Jin Wang ◽  
Tian Qin ◽  
Xuhui Liu ◽  
Xiang Wu
Keyword(s):  
Control Strategy ◽  
Feed Forward ◽  
Grid Voltage ◽  
Feed Forward Control ◽  
Virtual Impedance

scholarly journals Integrated Control of Hydromechanical Variable Transmissions

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Shujun Yang ◽  
Yong Bao ◽  
Xianzhi Tang ◽  
Xiaojuan Jiao ◽  
Deqing Yang ◽  
...  
Keyword(s):  
Control Strategy ◽  
High Efficiency ◽  
Control Strategies ◽  
Integrated Control ◽  
Range Shift ◽  
Heavy Vehicles ◽  
Shift Control ◽  
Speed Fluctuation ◽  
Variable Transmission ◽  
Stable Stage

A hydromechanical variable transmission (HMT) has advantages of continuous variation and high efficiency. So it is one of the ideal transmissions of heavy vehicles. The continuous speed varying process involves speed governing in range and range shift. Integrated control strategy of the HMT is proposed in this paper. The algorithm of the asymmetric saturated incremental proportional integral derivative (PID) speed control strategy in range and range shift conditions are derived. And this paper presents the range shift logic and range shift control strategies. A controller model is built in Matlab Simulink and cosimulated with the model of vehicle equipped with a two-range HMT. The HMT prototype hardware-in-the-loop simulation (HILS) platform of the integrated control strategy is built. The HILS results show that the range shift process is smooth and speed fluctuation does not happen. In the throttle stable stage, the engine speed is adjusted to the near optimal speed, and its change rules are in accordance with simulation results. The integrated control strategy is reasonable.

scholarly journals Numerical Investigation of a Process Control for the Roller Levelling Process Based on a Force Measurement

2016 ◽  
Vol 854 ◽  
pp. 249-254 ◽  
Author(s):  
Markus Grüber ◽  
Gerhard Hirt
Keyword(s):  
Process Control ◽  
Control Strategy ◽  
Material Properties ◽  
Force Measurement ◽  
Control Strategies ◽  
Fe Model ◽  
The Finite Element Method ◽  
Feed Forward Control ◽  
Strip Length ◽  
Control Curves

When processing conventional semi-finished metal strips, distinctive changes in the material properties along the strip length are unavoidable. The roller levelling process is sensitive to changes of those strip characteristics. Thus, a process control allowing for an online adaption of the roller levelling machine according to the actual strip characteristics is highly desirable. In order to enable a precise process layout, the calculation by the Finite Element Method (FEM) provides a suited strategy. Furthermore, the coupling of user-subroutines to an FE code offers the possibility to implement and test respective control strategies. This work proposes a control strategy that is based on a force measurement in the first load triangle of a levelling machine. A first FE model including a feedback control is used to calculate the dependence between the force in the first load triangle and the roll intermesh in the last load triangle leading to a flat sheet. The results are transferred to meta models – so called control curves – that give a direct relationship between the measured force and the roll intermesh. Within a second FE setup a feed-forward control based on these control curves is implemented and the proposed control strategy is investigated for varying yield strengths along the strip length. Thus, the time consuming FE simulations that are necessary to obtain the control curves are decoupled from the actual levelling process. According to the obtained results, the introduced approach is able to improve the sheet flatness for thin sheets when a change in the material properties occurs.

Improved Control Strategy of Grid Side Rectifier for the Double-Fed Wind Power System

2013 ◽  
Vol 694-697 ◽  
pp. 2143-2148
Author(s):  
Gan Xiao
Keyword(s):  
Power System ◽  
Wind Power ◽  
Control Strategy ◽  
Matlab Simulation ◽  
Feed Forward ◽  
Energy Feedback ◽  
Feed Forward Control ◽  
Wind Power System ◽  
Grid Side ◽  
Instantaneous Energy

In the double-fed wind power system, gird voltage sags would result in some serious problems such as a fluctuation of the DC-link voltage, an instantaneous energy feedback from turbine side to grid side, which affected the steady performance of the wind power system. According to these problems, a dynamic feed forward control strategy based on the traditional feed forward control was studied, with an inhibition of above disturbances. MATLAB simulation and DSP experiments verify the effectiveness of the improved control strategy.

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