scholarly journals Emulation of grid-forming inverters using real-time PC and 4-quadrant voltage amplifier

2021 ◽  
Author(s):  
Wolf Schulze ◽  
Maurizio Zajadatz ◽  
Michael Suriyah ◽  
Thomas Leibfried
Keyword(s):  
Real Time ◽  
Control Method ◽  
Current Control ◽  
Control Methods ◽  
Test Bed ◽  
Test Scenario ◽  
Power Semiconductors ◽  
Voltage Amplifier ◽  
Grid Side ◽  
Virtual Synchronous Machine

AbstractA test bed for the evaluation of novel control methods of inverters for renewable power generation is presented. The behavior of grid-following and grid-forming control in a test scenario is studied and compared.Using a real-time capable control platform with a cycle time of 50 µs, control methods developed with Matlab/Simulink can be implemented. For simplicity, a three-phase 4‑quadrant voltage amplifier is used instead of an inverter. Thus, the use of modulation and switched power semiconductors can be avoided. In order to show a realistic behavior of a grid-side filter, passive components can be automatically connected as L‑, LC- or LCL-filter. The test bed has a nominal active power of 43.6 kW and a nominal voltage of 400 V.As state-of-the-art grid-following control method, a current control in the d/q-system is implemented in the test bed. A virtual synchronous machine, the Synchronverter, is used as grid-forming control method. In combination with a frequency-variable grid emulation, the behavior of both control methods is studied in the event of a load connection in an island grid environment.

Real-time nonlinear speed control of an induction motor based on a new advanced integral backstepping approach

2019 ◽  
Vol 42 (2) ◽  
pp. 244-258 ◽  
Author(s):  
Bilel Aichi ◽  
Mohamed Bourahla ◽  
Khedidja Kendouci ◽  
Benyounes Mazari
Keyword(s):  
Real Time ◽  
Induction Motor ◽  
High Performance ◽  
Control Method ◽  
Current Control ◽  
Lyapunov Theory ◽  
External Disturbances ◽  
Low Speed ◽  
Backstepping Approach ◽  
Time Motor

This work proposes a robust control scheme of a three-phase induction motor using a new Backstepping approach based on variable gains. Because of the saturation blocks that are essential to protect the control system, the use of conventional integral Backstepping could lead to a modest performance represented by overshooting and strong vibrations in transitional regimes that cause overcurrent. To develop an efficient and simple control algorithm, the variable gains propriety is used in the speed controller to offer a quick response without overshooting with good robustness against external disturbances. The same property has been introduced in current regulation by a different mean in order to develop a new solution to solve obstacles related to very low-speed operations. The asymptotic stability of the global control is proven by Lyapunov theory. The improvement of the new version compared with the classical one was verified by a brief comparative study based on simulation results. The proposed algorithm has been implemented in a dSPACE DS 1104 card, to analyze the real-time motor performance, and to test control sensitivity against parametric variations. The obtained results show a remarkable improvement of the new control concerning rapidity and stability of transient regimes, overtaking elimination and reduction of starting current, with a low algorithm sensitivity against parametric variations. We have also been able to confirm that the new current control method can guarantee optimal regulation in order to achieve a high-performance operation at very low-speed zones, in the presence of various internal and external disturbances.

Control Strategies for Distributed Real-Time Control With Time Delays and Packets Losses

2004 ◽  
Author(s):  
Kun Ji ◽  
Ajit Ambike ◽  
Won-Jong Kim
Keyword(s):  
Time Delay ◽  
Real Time ◽  
Packet Loss ◽  
Time Delays ◽  
Open Loop ◽  
Current Control ◽  
Test Bed ◽  
Real Time Control ◽  
Packet Losses ◽  
Time Operation

Investigation on using network for distributed systems is an important topic in the motion control industry. This paper presents solutions to time-delay and packet-loss problems encountered in distributed real-time operation of an open-loop unstable magnetic levitation (maglev) test bed via an Ethernet. A novel model predictive control strategy with optimal controller design is developed to overcome the adverse influences of time delays and packet losses. By using the prediction of system states and the event-driven and time-driven smart actuator simultaneously, the plant receives the current control signal in every sampling interval even at the presence of time delays and packet losses. Thus we can compensate the time-delay and packet-loss in a uniform way. The simulation and experimental results demonstrated the feasibility and effectiveness of this control algorithm for NCSs with long stochastic time delays and successive packet losses.

A Control Method to Suppress Resonance and Improve Current Quality for Inverter System with LCL Filter

2014 ◽  
Vol 644-650 ◽  
pp. 3528-3533
Author(s):  
Yong Peng Lin ◽  
Shun Tao ◽  
Xiang Ning Xiao ◽  
Mei Rong Wu
Keyword(s):  
Control Method ◽  
Current Control ◽  
Utilization Efficiency ◽  
Control Effect ◽  
Lcl Filter ◽  
Loop Control ◽  
Grid Voltage ◽  
Grid Current ◽  
Differential Voltage ◽  
Grid Side

The LCL filter is easy to resonate, especially in the new energy power system with multiple inverters. The LCL filter resonant formulas are derived in this paper and a novel double closed loop control strategy combing with the structure of the LCL filter was proposed at the base on feedback of capacitor current as a result. In the control system, the inner loop feedback the first differential voltage of filter inductor at the grid side to damp the resonance and nature of first differential voltage of filter inductor is explained; the grid current outer loop achieves direct control of the grid current for high power factor and utilization efficiency. The simulation results show that the grid-side inductor voltage differential feedback control have a better current control effect both in the condition of the normal power grid voltage and distorted grid voltage, and the fluctuations of power and dc voltage are reduced.

Design of Single-Phase Active Power Filter

2013 ◽  
Vol 329 ◽  
pp. 421-425
Author(s):  
Xi Feng Xie ◽  
Li Ling Zheng
Keyword(s):  
Real Time ◽  
Single Phase ◽  
Control Method ◽  
Design Method ◽  
Active Power Filter ◽  
Active Power ◽  
Control Methods ◽  
Experimental Platform ◽  
Power Filter ◽  
Detecting Method

Aiming at the features of complexity, poor real-time and Low-accuracy of single-phase Active Power Filter (APF), and the problem of impossible parallel computation in the traditional DSP software realization, new design method of APF Based on FPGA is proposed, This paper focuses on the study of the harmonic current detecting method and improves control method of compensate current, it builds an experimental platform with FPGA EP1C12Q240C8 as the controller, the experimental results all support the effectiveness and correctness of the control methods and design methods of APF.

scholarly journals A Theoretical Concept of Decoupled Current Control Scheme for Grid-Connected Inverter with L-C-L Filter

2021 ◽  
Vol 11 (14) ◽  
pp. 6256
Author(s):  
Mohamad Amin Ghasemi ◽  
Seyed Fariborz Zarei ◽  
Saeed Peyghami ◽  
Frede Blaabjerg
Keyword(s):  
Control Method ◽  
Controller Design ◽  
Current Control ◽  
System Stability ◽  
State Equations ◽  
Lcl Filter ◽  
Control Scheme ◽  
Grid Connected Inverter ◽  
The Stability ◽  
Grid Side

This paper proposes a nonlinear decoupled current control scheme for a grid-connected inverter with LCL filter. Decoupling the active and reactive current control channels is one of the main demands in the control of inverters. For inverters with an L filter, the decoupling can be achieved by a proper feed-forward of grid voltages. However, the coupling of channels is a complex issue for converters with LCL filters. The resonance mode of the LCL filter may cause instability, which adds more complexity to the analysis. In this paper, state equations of the system are provided, which highlight the coupling between active and reactive currents injected into the grid. Accordingly, a non-linear control scheme is proposed which effectively decouples the channels and dampens the resonant modes of the LCL filter. The stability of the proposed control method is verified by the Lyapunov criterion. Independency of the system stability to the grid-impedance is another feature of the proposed approach. Moreover, only grid-side currents are needed for implementation of the proposed scheme, avoiding the need for additional current sensors for the output capacitor and grid-side inductor. For accurate modelling of the inverter, the computation and PWM sampling delays are included in the controller design. Finally, various case studies are provided that verify the performance of the proposed approach and the stability of the system.

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