scholarly journals A Simplified Optimal-Switching-Sequence MPC with Finite-Control-Set Moving Horizon Optimization for Grid-Connected Inverter

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 457 ◽  
Author(s):  
Longyun Kang ◽  
Jiancai Cheng ◽  
Bihua Hu ◽  
Xuan Luo ◽  
Jianbin Zhang
Keyword(s):  
Cost Function ◽  
Digital Signal Processor ◽  
Digital Signal ◽  
Continuous Control ◽  
Optimal Switching ◽  
Switching Sequence ◽  
Finite Center ◽  
Finite Control ◽  
Control Set ◽  
Grid Connected Inverter

Optimal-switching-sequence model-predictive-control (OSS-MPC) strategy, a popular kind of continuous-control-set MPC (CCS-MPC), has been used to address the variable frequency of finite-control-set MPC (FCS-MPC). Since the digital signal processor (DSP) does not have a dedicated divider, it requires a large amount of computation for the division operations in OSS searching. Here, a simplified OSS-MPC absorbing the merits of FCS-MPC is proposed to reduce the computational burden of conventional OSS-MPC. The proposed method uses a novel cost function whose candidates are the finite center vectors instead of switching sequences, which can avoid duty cycle computation and convert the moving horizon optimization of CCS-MPC into that of FCS-MPC. Besides, the derivatives of the active and reactive powers are divided into the constant terms and variable terms. The constant terms are extracted from the cost function. Experimental and simulation results show that the computational amount of the proposed algorithm is only 36.34% of that of the conventional OSS-MPC. Meanwhile, the simplified OSS-MPC still maintains the excellent dynamic and steady state performance of conventional OSS-MPC.

scholarly journals Continuous Control Set Predictive Current Control for Induction Machine

2021 ◽  
Vol 11 (13) ◽  
pp. 6230
Author(s):  
Toni Varga ◽  
Tin Benšić ◽  
Vedrana Jerković Štil ◽  
Marinko Barukčić
Keyword(s):  
Control Method ◽  
Induction Machine ◽  
Current Control ◽  
Continuous Control ◽  
Loop Model ◽  
Voltage Reference ◽  
Control Loop ◽  
Speed Tracking ◽  
Finite Control ◽  
Control Set

A speed tracking control method for induction machine is shown in this paper. The method consists of outer speed control loop and inner current control loop. Model predictive current control method without the need for calculation of the weighing factors is utilized for the inner control loop, which generates a continuous set of voltage reference values that can be modulated and applied by the inverter to the induction machine. Interesting parallels are drawn between the developed method and state feedback principles that helped with the analysis of the stability and controllability. Simple speed and rotor flux estimator is implemented that helps achieve sensorless control. Simulation is conducted and the method shows great performance for speed tracking in a steady state, and during transients as well. Additionally, compared to the finite control set predictive current control, it shows less harmonic content in the generated torque on the rotor shaft.

scholarly journals Total Harmonic Distortion Oriented Finite Control Set Model Predictive Control for Single-Phase Inverters

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3467 ◽  
Author(s):  
Po Li ◽  
Ruiyu Li ◽  
Haifeng Feng
Keyword(s):  
Model Predictive Control ◽  
Cost Function ◽  
Predictive Control ◽  
Single Phase ◽  
Tracking Error ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Finite Control ◽  
Control Set ◽  
The Cost

Inverters are commonly controlled to generate AC current and Total Harmonic Distortion (THD) is the core index in judging the control effect. In this paper, a THD oriented Finite Control Set Model Predictive Control (FCS MPC) scheme is proposed for the single-phase inverter, where a optimization problem is solved to obtain the switching law for realization. Different from the traditional cost function, which focuses on the instantaneous deviation of amplitude between predictive current and its reference, we redesign a cost function that is the linear combination of the current fundamental tracking error, instantaneous THD value and DC component in one fundamental cycle (for 50 Hz, it is 0.02 s). Iterative method is developed for rapid calculation of this cost function. By choosing a switching state from a FCS to minimize the cost function, a FCS MPC is finally constructed. Simulation results in Matlab/Simulink and experimental results on rapid control prototype platform show the effect of this method. Analyses illustrate that, by choosing suitable weight of the cost function, the performance of this THD oriented FCS MPC method is better than the traditional one.

scholarly journals Multi-Step Finite Control Set Model Predictive Control For Three-level APF

2021 ◽  
Vol 257 ◽  
pp. 01087
Author(s):  
DeJiYang Zong ◽  
Shifeng Hu ◽  
XuGuang Yang
Keyword(s):  
Tracking Error ◽  
Control Process ◽  
Prediction Method ◽  
Relevant Information ◽  
Single Step ◽  
Optimal Switching ◽  
Harmonic Compensation ◽  
Finite Control ◽  
Time Optimal ◽  
Control Set

Compared with the two-level APF, the three-level neutral point clamped (ANPC) has more output levels, less harmonic influence, and lower equipment loss in the process of harmonic compensation. However, due to the conservatism of single-step prediction, it can only provide the reliability at k+1 time, and it does not provide the relevant information for the next time optimal. Moreover, the control of threelevel APF needs to consider multiple targets at the same time, which will cause certain tracking error. In this paper, a multi-step prediction method is proposed. The optimal and suboptimal switching states at k+1 are obtained by cycling. The optimal switching states in two control cycles can be obtained by substituting the optimal switching states at k+2. The method improves the reliability of the control process, and the simulation results show that the harmonic content of the power grid is low, which meets the relevant requirements.

DSP - Based Islanding Protection for Photovoltaic Grid Connected Inverter

2013 ◽  
Vol 291-294 ◽  
pp. 2007-2010
Author(s):  
Khanchai Tunlasakun
Keyword(s):  
Digital Signal Processor ◽  
Digital Signal ◽  
Local Load ◽  
Grid Voltage ◽  
National Instrument ◽  
Point Of Common Coupling ◽  
Common Coupling ◽  
Utility Grid ◽  
Grid Connected Inverter ◽  
Signal Processor

This research presents the DSP - based islanding protection for photovoltaic grid connected inverter with under / over frequency and under / over voltage islanding protection methods. The design is based on the TMS320VC33PGE digital signal processor on the NI SPEEDY 33 board from National Instrument Inc. The prototype is monitor the grid frequency and grid voltage at the point of common coupling (PCC) between the photovoltaic grid connected inverter, the local load and the distribution. The results of study, the prototype can turn off relay between photovoltaic grid connected inverter and utility grid when the frequency is change under 48Hz or over 52Hz and the voltage is change under 200V or over 240V.

A New Method Used to Eliminate the DC Component of Grid-Connected Inverter

2013 ◽  
Vol 347-350 ◽  
pp. 1557-1560
Author(s):  
Zhi Yu Wang ◽  
Yong Qiang Zhu
Keyword(s):  
Digital Signal Processor ◽  
Digital Signal ◽  
Decoupling Control ◽  
New Method ◽  
Elimination Method ◽  
Simulation Results ◽  
Dc Component ◽  
Grid Connected Inverter ◽  
The Impact ◽  
Conditioning Circuit

Due to the impact from the conditioning circuit, it is easy to generate DC component for the reference voltage when the digital signal processor (DSP) sampling the grid voltage. It cannot eliminate the DC component for the grid inverter based on feed-forward decoupling control, and this would bring the DC component to the inverter voltage. The traditional DC component elimination method includes two aspects of hardware and software. This paper presents a new method to eliminate the DC component. The simulation results show that the algorithm is correct by using PSCAD/EMTDC.

scholarly journals Finite control set model predictive control to balance DC-link capacitor voltage for TType NPC inverter of grid-connected photovoltaic systems

2015 ◽  
Vol 18 (3) ◽  
pp. 5-17
Author(s):  
Dzung Quoc Phan ◽  
Tuyen Dinh Nguyen ◽  
Nhat Minh Nguyen
Keyword(s):  
Model Predictive Control ◽  
Cost Function ◽  
Predictive Control ◽  
Switching Frequency ◽  
Photovoltaic Systems ◽  
Delay Compensation ◽  
Capacitor Voltage ◽  
Finite Control ◽  
Control Set ◽  
The Cost

This paper proposes the Finite control set Model Predictive Control (FCS-MPC) with delay compensation for three-phase threelevel T-Type NPC inverter (T-Type NPC) of grid-connected photovoltaic systems (PV). The proposed FCS-MPC controls the objectives: current tracking control, DC-link capacitor voltage balance, the reduction of switching frequency to ensure issues of the power quality and improve the efficiency of grid-connected of PV system. The cost function of the proposed FCS-MPC uses the 27 possible switching states generated by TType NPC, the optimal switching state is selected in each sampling time that minimizes the cost function. The proposed FCS-MPC has also proposed the delay compensation with two-step prediction horizon at time k+2 to reduce the total harmonic distortion (THD) of the grid current. The proposed FCS-MPC is verified by using Matlab/Simulink.

scholarly journals A Comparison of Finite Control Set and Continuous Control Set Model Predictive Control Schemes for Model Parameter Mismatch in Three-Phase APF

2021 ◽  
Vol 9 ◽  
Author(s):  
Jianfeng Yang ◽  
Yang Liu ◽  
Rui Yan
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Parameter Uncertainty ◽  
Prediction Error ◽  
Continuous Control ◽  
Power Electronic ◽  
Parameter Mismatch ◽  
Three Phase ◽  
Finite Control ◽  
Control Set

Model predictive control (MPC) methods are widely used in the power electronic control field, including finite control set model predictive control (FCS-MPC) and continuous control set model predictive control (CCS-MPC). The degree of parameter uncertainty influence on the two methods is the key to evaluate the feasibility of the two methods in power electronic application. This paper proposes a research method to analyze FCS-MPC and CCS-MPC’s influence on the current prediction error of three-phase active power filter (APF) under parameter uncertainty. It compares the performance of the two model predictive control methods under parameters uncertainty. In each sampling period of the prediction algorithm, different prediction error conditions will be produced when FCS-MPC cycles the candidate vectors. Different pulse width modulation (PWM) results will be produced when CCS-MPC solves the quadratic programming (QP) problem. This paper presents the simulation results and discusses the influence of inaccurate modeling of load resistance and inductance parameters on the control performance of the two MPC algorithms, the influence of reference value and state value on prediction error is also compared. The prediction error caused by resistance mismatch is lower than that caused by inductance mismatch, more errors are caused by underestimating inductance values than by overestimating inductance values. The CCS-MPC has a better control effect and dynamic performance in parameter mismatch, and the influence of parameter mismatch is relatively tiny.

Finite Control Set Model Predictive Current Control FCS-MPC Based on Cost Function Optimization, with Current Limit Constraints for Four-Leg VSI

2016 ◽  
Vol 12 (1) ◽  
pp. 43-53
Author(s):  
Riyadh Omar ◽  
Rabee Thejel
Keyword(s):  
Cost Function ◽  
Pulse Width Modulation ◽  
Control Strategies ◽  
Current Control ◽  
Function Optimization ◽  
System Response ◽  
Simulink Model ◽  
Current Limit ◽  
Finite Control ◽  
Control Set

A Matlab/Simulink model for the Finite Control Set Model Predictive current Control FCS-MPC based on cost function optimization, with current limit constraints for four-leg VSI is presented in this paper, as a new control algorithm. The algorithm selects the switching states that produce minimum error between the reference currents and the predicted currents via optimization process, and apply the corresponding switching control signals to the inverter switches. The new algorithm also implements current constraints which excludes any switching state that produces currents above the desired references. Therefore, the system response is enhanced since there is no overshoots or deviations from references. Comparison is made between the Space Vector Pulse Width Modulation SVPWM and the FCS-MPC control strategies for the same load conditions. The results show the superiority of the new control strategy with observed reduction in inverter output voltage THD by 10% which makes the FCS-MPC strategy more preferable for loads that requires less harmonics distortion.

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