Based on Feed-Forward Photovoltaic Grid Converter Control Strategy

2012 ◽  
Vol 220-223 ◽  
pp. 2052-2056
Author(s):  
Xing Jia Yao ◽  
Jin Hua Zhu ◽  
Ying Ming Liu ◽  
Xiao Dong Wang ◽  
Hong Fang Xie
Keyword(s):  
Control Strategy ◽  
Current Frequency ◽  
Feed Forward ◽  
Current Wave

In photovoltaic grid-connected system, the method of adding voltage feed-forward to improve the shape of grid-connected current wave is presented, the reason for the introduction of the net voltage feed-forward decreasing the phasic difference between grid-connected current and net voltage and reducing the THD of grid-connected current is analyzed. It is confirmed that the net voltage feed-forward compensation can improve grid-connected current availably by the results of simulations and experiments, keep the current frequency and phase synchronous to the grid.

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.

Modeling and Control of an Infinitely Variable Speed Converter With Application to Wind Turbines

2012 ◽  
Author(s):  
W. D. Zhu ◽  
X. F. Wang
Keyword(s):  
Wind Turbine ◽  
Kinematic Model ◽  
Power Converter ◽  
Output Shaft ◽  
Speed Ratio ◽  
Variable Speed ◽  
Average Output ◽  
Constant Frequency ◽  
Current Frequency ◽  
Feed Forward

Traditional transmission in wind turbine applications has a constant output-to-input speed ratio, which needs a power converter to regulate the current frequency that can be fed into the grid. Different types of continuously variable transmission (CVT) have been developed for vehicle and wind turbine applications, which can generate constant-frequency current without using a power converter in a wind turbine. An infinitely variable speed converter (IVSC) is a specific type of CVT that can achieve a zero speed ratio and transmit a large torque at a low speed ratio. An IVSC with drivers that convert an eccentric motion of cams to a concentric motion of the output shaft through one-way bearings is introduced, and an active control system with a combined feedback and feed forward control that can automatically adjust the eccentricity of the outer cams to control the speed ratio of the transmission is developed. The kinematic model of the IVSC is derived and fitted by a polynomial function to serve as the feed forward function in the control law. The feedback control is used to reduce the system error. A dynamic model of the IVSC is derived to investigate the effect of the dynamic load on the input and output speeds. Static and dynamic tests were conducted to validate the kinematic model of the IVSC. The variation of the average output speed per revolution of the output shaft is 0.56% with respect to the desired output speed in the simulation and 0.91% in the experiments.

Roll-Gap Control System of Twin Roll Strip Caster Based on Feed Forward-Feedback

2013 ◽  
Vol 750 ◽  
pp. 64-67
Author(s):  
Wen Yu Zhang ◽  
Dong Ying Ju ◽  
Yao Yao ◽  
Hong Yang Zhao ◽  
Xiao Dong Hu ◽  
...  
Keyword(s):  
Control System ◽  
Control Strategy ◽  
Feedback System ◽  
Experimental Results ◽  
Convergence Time ◽  
Feed Forward ◽  
Gap Control ◽  
Roll Gap ◽  
Twin Roll

In this paper, the established control system and its control algorism of a new twin roll strip caster developed by authors is presented. It is illustrated the roll-gap control strategy of the twin roll strip caster based on a feed forward-feedback system. From the experimental results, the susceptibility of control convergence time, stable and accurate are shown on a higher level than traditional control strategy.

Adaptation for Air-Intake System Throttle Control in a Gasoline Engine With Low-Pressure Exhaust-Gas Recirculation

2015 ◽  
Author(s):  
Mario Santillo ◽  
Suzanne Wait ◽  
Julia Buckland
Keyword(s):  
Feedback Control ◽  
Control Strategy ◽  
Gasoline Engine ◽  
Exhaust Gas Recirculation ◽  
Lookup Table ◽  
Exhaust Gas ◽  
Feed Forward ◽  
Intake System ◽  
Air Intake ◽  
Gas Recirculation

We investigate control strategies for traditional throttle-in-bore as well as low-cost cartridge-style throttle bodies for the air-intake system (AIS) throttle used in low-pressure exhaust-gas recirculation (LPEGR) on a turbocharged gasoline engine. Pressure sensors placed upstream and downstream of the AIS throttle are available as signals from the vehicle’s engine control unit, however, we do not use high-bandwidth feedback control of the AIS throttle in order to maintain frequency separation from the higher-rate EGR loop, which uses the downstream pressure sensor for feedback control. A design-of-experiments conducted using a feed-forward lookup table-based AIS throttle control strategy exposes controller sensitivity to part-to-part variations. For accurate tracking in the presence of these variations, we explore the use of adaptive feedback control. In particular, we use an algebraic model representing the throttle plate effective opening area to develop a recursive least-squares (RLS)-based estimation routine. A low-pass filtered version of the estimated model parameters is subsequently used in the forward-path AIS throttle controller. Results are presented comparing the RLS-based feedback algorithm with the feed-forward lookup table-based control strategy. RLS is able to adapt for part-to-part and change-over-time variabilities and exhibits an improved steady-state tracking response compared to the feed-forward control strategy.

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.

Research on Current Control of Photovoltaic Grid-Connected Inverter

2013 ◽  
Vol 291-294 ◽  
pp. 2446-2451
Author(s):  
Yan Zhang ◽  
Wei Wang ◽  
Shi Tao Wang
Keyword(s):  
Phase Difference ◽  
Field Experiments ◽  
Current Control ◽  
Experimental Results ◽  
Current Frequency ◽  
Feed Forward ◽  
Grid Voltage ◽  
Feed Forward Control ◽  
Grid Connected Inverter

Grid-voltage feed-forward control was added to improve the grid-connected current quality on photovoltaic grid-connected inverter. The method decreases the phase difference between the grid-connected current and grid voltage and reduces the total harmonics distortion (THD) of grid-connected current. So the grid-voltage feed-forward compensation can improve grid-connected current availably and keep the current frequency and phase synchronous to the grid. The study is validated through simulations and field experiments. Experimental results obtained on 2.5-kw inverter demonstrate the feasibility of the proposed method.

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 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
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