This paper investigates the use of a model-predictive control strategy to control a direct matrix converter. The proposed control method combines the features of the classical model-predictive control and the space vector modulation technique into a modulated model-predictive control. This new solution maintains all the characteristics of model-predictive control (such as fast transient response, multiobjective control using only one feedback loop, easy inclusion of nonlinearities and constraints of the system, and the flexibility to include other system requirements in the controller), adding the advantages of working at fixed switching frequency and improving the quality of the controlled waveforms. Simulation and experimental results employing the control method to a direct matrix converter are presented.

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Control of a Direct Matrix Converter With Modulated Model-Predictive Control

This paper presents a novel model predictive control (MPC) for the T-type single-phase three-level inverters. The cumbersome procedure in tuning of weighting factors is eliminated so that the implementation of the proposed MPC becomes easy. The constant switching frequency is achieved during the control implementation in order to facilitate the filter design. In order to optimize the distribution of the output current harmonics, multiple voltage vectors are employed in each control cycle with their application times setting inversely proportion to the respective cost function. The redundant small voltage vectors are utilized to balance the neutral point voltage of the inverter by directly regulating the upper and lower dc-link capacitors voltages. Finally, the proposed MPC algorithm is experimentally evaluated and compared with other two unfixed switching frequency MPC algorithms in terms of the steady state, transient performance, and parameter sensitivity.

A Constant Switching Frequency Model Predictive Control Without Weighting Factors for T-Type Single-Phase Three-Level Inverters

Conventional finite control set model-predictive control (FCS-MPC) presents a high computational burden, especially in three-level neutral-point-clamped (NPC) converters. This article proposes a low-complexity optimal switching time-modulated model-predictive control (OST-M2PC) method for a three-level NPC converter. In the proposed OST-M2PC method, the optimal switching time is calculated using a cost function. Compared with the conventional FCS-MPC, the proposed OST-M2PC method has a fixed switching frequency as well as better power quality. The proposed OST-M2PC can operate at a 20-kHz sampling frequency, reducing the computational burden of the processor. Simulation and experimental results validate the operation of the proposed method.

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A Low-Complexity Optimal Switching Time-Modulated Model-Predictive Control for PMSM With Three-Level NPC Converter

Conventional model predictive control (MPC) suffers from unfixed switching frequency, heavy computational burden, and cumbersome weighting factors’ tuning, especially for multilevel inverter applications due to a large number of voltage vectors. To address these concerns, this article proposes multiple-voltage-vector (MVV) MPC algorithms with reduced complexity and fixed switching frequency for T-type three-phase three-level inverters. First, MMVs are adopted during each control period, and their execution times are set according to the predefined cost functions. Second, weighting factors for balancing the neutral point (NP) voltage in the cost function are eliminated by utilizing redundant voltage vectors, which simplifies the control implementation. Third, through mapping the reference voltage in the first large sector, the calculation complexity for the execution times of voltage vectors in different large sectors becomes much lower. Finally, main experimental results were presented to validate the effectiveness of the proposed algorithms.

Multiple-Voltage-Vector Model Predictive Control With Reduced Complexity for Multilevel Inverters

In this article, a double-vector-based model predictive control (MPC) method with efficient computation for single-phase five-level active neutral-point clamped (5L-ANPC) converters is proposed. It uses double voltage vectors per control cycle rather than the single in the conventional MPC method, resulting in reduced output current ripples and fixed switching frequency. First, the MPC method based on the Lyapunov function is optimized to select two voltage sectors rather than 25, reducing the calculation complexity significantly. Then, two current tracking algorithms based on double voltage vectors are presented, which are using the current cost function and current slope, respectively. Finally, a fast voltage balancing scheme for the dc-link and flying capacitors is developed and embedded in the MPC method. Both simulated and experimental results are used to validate the correctness and feasibility of the proposed MPC method.

Double-Vector Model Predictive Control for Single-Phase Five-Level Actively Clamped Converters

Advances in power electronic converters technology along with the wide range of applications require sophisticated digital control schemes In the recent years Finite Control Set Model Predictive Control (FCS-MPC) has been successfully proposed as an alternative to the traditional control techniques, due to its fast dynamic response, easy inclusion of nonlinearities and constraints in the control algorithm and the ability of incorporate several control requirements in one cost function However, FCS-MPC is characterized by a variable switching frequency which can cause a degradation in system performance, or demand higher output filtering In this paper a Modulated Model Predictive Control (M2PC) strategy is proposed for constant switching frequency operation and verified with a neutral-point-clamped (NPC) converter for load current regulation and DC-link capacitor voltages balancing The aim of this control technique is to obtain a modulated waveform at the output of the converter, whilst maintaining all the desired characteristics of FCS-MPC The feasibility of this strategy is evaluated using simulation and compared to the classical FCS-MPC strategy

M. Perez

Papers

Modulated model predictive control (M 2 PC) with fixed switching frequency for an NPC converter