Control Of Matrix Converter Research Articles

Low-Frequency Circulating Current Injection in Eight-Component Control for Modular Multilevel Matrix Converter Under Equal Frequency

Low-Frequency Circulating Current Injection in Eight-Component Control for Modular Multilevel Matrix Converter Under Equal Frequency

Control and Performance Analysis of an Indirect Matrix Converter Fed Triple Star Induction Motor

Efficient operation is a recommended factor in most of industrial applications. In this paper, an indirect matrix converter (IMC) topology is developed and proposed to substitute the classical (AC/DC/AC) three phase converter topologies; where the control strategy is frequently performed with a voltage source inverter (VSI). Large electrolytic capacitors are viewed as hazardous due to their short lifetime compared to ordinary capacitors and power switches, as well as their contribution to the total bulk and weight of the converter. Matrix converters may be the answer to getting rid of the capacitor, shrinking the converter, and improving its efficiency (MC). These advantages are offset by the fact that the (MC) calls for a tricky switching technique based on pulse width modulation, which is prone to commutation failure. The direct frequency conversion using the indirect matrix converter (IMC) with many advantages has appeared as an alternative to these conventional voltage inverters. This study investigates a field-oriented control (FOC) scheme for indirect matrix converter fed triple star induction motor (TSIM). After building the proposed IMC converter topology, an adequate field-oriented control strategy-based space vector modulation (SVM) is proposed and adapted for the control of the triple star induction motor. The FOC technique guarantees flux and torque decoupling while ensuring good operation performance as required in many industrial applications. The obtained numerical simulation results show and confirm the effectiveness of this control scheme.

Decentralized Power Sharing With Backstepping Control for Modular High-Frequency Link Matrix Converter

Decentralized Power Sharing With Backstepping Control for Modular High-Frequency Link Matrix Converter

Design and control of modular multilevel matrix converter with symmetrically integrated energy storage for low frequency AC system

AbstractIntegrating energy storage units (ESUs) into part of sub‐modules (SMs) enables the decoupling active power control for the modular multilevel matrix converter (M3C). The low frequency AC (LFAC) system based on M3C with symmetrically integrated energy storage (SI‐AM3C) can provide functions such as renewable power fluctuation smoothing and other power grid auxiliary services, which is attractive in engineering practices. This paper focuses on the design and control of SI‐AM3C. For the converter design, an evaluation method for the number of required active SMs (ASMs) is presented. On this basis, the influences of different system operating conditions on the ASM requirement are analyzed in case studies, and the effects of specific circulating injection strategies are also investigated. The control system targeted at decoupled AC side active power for SI‐AM3C is introduced. A modified inner‐arm capacitor voltage balance strategy is introduced to reduce the capacitor voltage deviation between ASMs and passive SMs (PSMs). The conclusions related to the presented estimation method and converter control strategy are verified by time‐domain simulations in PSCAD/EMTDC.

Grid power control of direct matrix converter fed three-phase induction generator

The direct matrix converter (DMC) and the modulation technique were presented in this paper, moreover the power of the grid is controlled. Due to its high flexibility and low computation demands, the DMC's most widely used modulation technique is space vector modulation. The double-side modulation is used in this paper instead of the single-side modulation because less harmonics at the input and output side can be obtained, however this would increase slightly the number of branch-switch-overs (BSO) for each switching period. In addition to being able to create input and output sinusoidal currents with various frequencies, it would adjust the input power factor. Along with that, the simple power control loop would regulate the grid power and then generate controlled three-phase reference signals for pulses generation accordingly. Results from the simulations show that the topology is appropriate for machine drive applications.

Application of machine learning controller in matrix converter based on model predictive control algorithm

Finite control set model predictive control (FCS-MPC) algorithms are famous in power converter for its easy implementation of constraints with cost function than classical control algortihms. However computation complexity increases when swicthing state is high for converters such as matrix converter, multilevel converters and this impose a serious drawback to compute multi-step prediction horizon MPC algorithm which further increases the computation. To overcome the above said difficulty, machine learning based artificial neural network (ANN) controller for matrix converter is proposed. The training data for ANN controller is derived from MPC algorithm and trained offline with an accuracy of 70.3%. The proposed ANN controller shows a similar and better performance than MPC controller in terms of total harmonic distortion (THD), peak overshoot during dynamic change in reference current and dynamic change in load parameter and less computation with less execution time. Further, ANN controller for matrix converter is tested in OPAL-RT using hardware in-loop (HIL) simulation and showed that it outperforms MPC controller.

Dynamic Performance Improvement of Continuous Control Set Model Predictive Control for High-Frequency Link Matrix Converter

In this paper, a comprehensive control strategy of a high frequency link matrix converter (HFLMC) based on the interaction technology between electric vehicle and power grid is proposed to improve the dynamic performance of the system. The continuous control set model predictive control (CCS-MPC) is applied to the current loop to solve the problems of difficult selection of PI control parameters and slow dynamic response speed. In order to ensure that the grid-connected current can achieve better command tracking, a deviation suppression term is introduced into the cost function of CCS-MPC, and the online auto tuning method of weight factors of fast-tracking term and deviation suppression term is designed. On this basis, the PWM signals are generated by the coordinated modulation strategy of the HFLMC to obtain a constant switching frequency, which makes the harmonic of the grid connected current easier to be filtered out. Experimental results show the correctness and feasibility of the proposed control strategy.

ANN Identification technique and fuzzy PI Control of a Hybrid Indirect Matrix Converter with a Flying Capacitor three level Inverter in Power Active Filtering Application

The current paper is concerned with fuzzy controllers employing neural networks to implement control over power electronics systems committed to power quality improvement in a distribution grid. An optimization method technique for tuning fuzzy PI controller gains is introduced to improve a Hybrid Indirect Matrix Converter's control with a flying capacitor three-level inverter (HIMC), and it is connected via an RL filter to the power grid (PG). The harmonics are identified by an Artificial Neural Network (ANN). The effectiveness of this method is shown in the simulation results by MATLAB/Simulink ( Simscap, simpower blocks).

Predictive Current Control for Three-Level Four-Leg Indirect Matrix Converter Under Unbalanced Input Voltage

In this paper, a robustness evaluation of model predictive current control with instantaneous reactive power minimization for a three-level four-leg indirect matrix converter is presented. Unbalanced voltages can be extremely dangerous, especially for motors and other inductive equipment. Unbalanced voltages can have a detrimental effect on equipment and the power system, which is exacerbated by the fact that a small phase voltage imbalance can result in a disproportionately large phase current imbalance. The robustness test is carried out by considering balance and unbalanced input voltages. The proposed control predicts the behavior of the load current and the instantaneous reactive power for every possible 96 switching states. Subsequently, it selects the optimum switching state which fulfils the objectives of the control without the need of modulators. The cost function has been adequately modified to consider the asymmetrical aspect of the input voltage. Experimental validation using a laboratory prototype was conducted by using FPGA under a wide range of input voltage unbalance. The experimental results show high fidelity load current reference tracking while maintaining relatively low instantaneous reactive power during the transient and steady-state condition. The percentage of reactive power after setting the optimal weighting factor, the average reactive power was found to reduce to approximately 10-20%.

Control Scheme Based on Improved Odd-Harmonic Repetitive Control for Third-Harmonic Injection Two-Stage Matrix Converter

The third-harmonic injection two-stage matrix converter (3TSMC) not only inherits the advantages of the conventional two-stage matrix converter (TSMC), but also has simple modulation strategy and low switching losses. The injection current control is the key to achieving sinusoidal input currents of 3TSMC. The injection current reference consists of the third harmonic and its odd harmonics, making it difficult to obtain high control accuracy with a proportional integral (PI) controller. In this paper, a control scheme is proposed for the injection current of 3TSMC, which consists of an improved odd-harmonic repetitive controller (IORC), a PI controller and a feedforward controller. Compared with the conventional repetitive controller (CRC) and existing odd-harmonic repetitive controllers (ORC), the IORC has the highest gains and bandwidths at odd-harmonic frequencies, offering the proposed control scheme high control accuracy and fast transient response. The stability conditions of the system with the proposed control scheme are analyzed, and the design guidelines for the control parameters are provided on this basis. The experimental results demonstrate the effectiveness of the proposed control scheme.

Modeling and Control of Modular Multilevel Matrix Converter for Low-Frequency AC Transmission

The modular multilevel matrix converter (M3C) is the core component in low-frequency AC (LFAC) transmission, which is a competitive scheme for offshore wind power integration. In this paper, the M3C control strategy with the reduced switching frequency SM voltage balancing method is proposed. First, based on the conventional αβ0 and dq transformations, the M3C mathematical model is derived. Then, the dual-loop control structure with outer loop and inner loop controllers commonly used in voltage source converters is applied to the M3C. The inner loop controller consists of the current tracking controller in the dq reference frame and the circulating current suppressing controller in the αβ0 reference frame; the outer loop controller is proposed for the offshore wind farm LFAC integration scenario. Additionally, according to the operating characteristics of full-bridge sub-modules (FBSMs), three characteristic variables are defined and a reduced switching frequency SM voltage balancing method based on the nearest level control (NLC) is proposed. Finally, time-domain simulations in PSCAD/EMTDC demonstrate the feasibility of the proposed control strategy.

Hardware Implementation and Closed Loop Simulation of SPWM and PI based Hybrid Control for Matrix Converter fed Single Phase Induction Motor Powered by PV system

Hardware Implementation and Closed Loop Simulation of SPWM and PI based Hybrid Control for Matrix Converter fed Single Phase Induction Motor Powered by PV system

Optimisation-based modulation and control of matrix converters: A closed-form solution

A new optimisation-based modulation and control design for matrix converters is proposed. The design uses a quadratic optimisation programme to seamlessly combine control requirements on the input and output sides of the converter. On the input side, the requirements are to keep the source voltage and current in phase with each other and to attenuate transient oscillations caused by a resonant RLC filter, which is used to protect the voltage source from undesirable harmonics. On the output side the requirement is to track a desired current to feed a load. The novel aspects of the scheme are that (i) the optimisation is posed in terms of the converter’s modulation matrix, whose entries represent the duty cycles of each of the converter switches; and that (ii) the solution of the optimisation is obtained in closed form and shown to be implementable with a small number of elementary operations. Simulation results demonstrate the good performance of the proposed design.

Predictive Algorithm for Control of Common Mode Voltage and Switching Frequency in Direct Matrix Converter Fed System

Multiobjective model predictive control (Mo-MPC), owing to its simplicity and adaptability to comply with diverse constraints, has gained popularity in the control of direct matrix converters (DMCs). However, the MPC strategy makes the converter operate at an uncontrolled and variable switching frequency, which may inhibit high power density applications due to increased power losses. This article proposes a method for controlling the switching frequency of the converter and simultaneously regulating the common mode voltage in the DMC fed system while maintaining sinusoidal load and source currents at near unity input power factor. Furthermore, in order to streamline the control while simultaneously dealing with these objectives, a suitable normalization technique is implemented for scaling the errors in each objective. This method is validated through simulation and experimental results.

Power decoupling control of single‐phase or three‐phase input high‐frequency single‐phase output matrix converters

AbstractThis study proposes a matrix converter (MC) control method capable of power decoupling (PD) for a single‐phase input isolated AC‐DC converter. The proposed converter can also be fed by a three‐phase source without any additional components. The PD circuit shares its capacitors with the input filters and its switches with the MC, and absorbs the source power ripple to supply a constant DC voltage for the load. Moreover, the MC control method achieves a sinusoidal source current, a high output frequency, and soft switching. Additionally, the feedback control to compensate for the DC output voltage error is applied. The proposed method is evaluated experimentally.

A computationally efficient torque and flux ripple reduction by active vector optimization approach using direct torque control–based model predictive torque control for matrix converter–fed permanent magnet synchronous motor

The Matrix Converter–fed Finite Control Set–Model Predictive Control is an efficient drive control approach that exhibits numerous advantageous features. However, it is computationally expensive as it employs all the available matrix converter voltage vectors for the prediction and estimation. The computational complexity increases further with respect to the inclusion of additional control objectives in the cost function which degrades the potentiality of this technique. This paper proposes two computationally effective switching tables for simplifying the calculation process and optimizing the matrix converter active prediction vectors. Here, three prediction active vectors are selected out of 18 vectors by considering the torque and flux errors of the permanent magnet synchronous motor. In addition, the voltage vector location segments are modified into 12 sectors to boost the torque dynamic control. The performance superiority of the proposed concept is analyzed using the MATLAB/Simulink software and the real-time validation is conducted by implementing in the real-time OPAL-RT lab setup.

Heterodyne Controlled Matrix Converter as a Direct Frequency Reduction Method for Microturbine Generators (MTG)

In this paper a control method for a matrix converter (MC) based on the heterodyne concept from the communication field is presented. The method is used to convert the high frequency of a microturbine generator’s (MTG) output voltage to the utility grid’s frequency. In this control method a frequency modulation (FM) of the MC’s switching frequency is achieved using a DQ0 analysis of the converter’s filtered output voltage with the utility grid’s frequency as a reference. After filtration, the MC achieves a conversion to the reference frequency with a minimal total harmonic distortion (THD) of the output voltage while using a low switching frequency. In addition, the proposed method decouples the output frequency, phase angle and voltage amplitude, which allows them to be controlled separately. This significantly simplifies the required control, and enables a robust and low-cost design. The theoretical analysis, simulation and experimental results of the method are reported.

RNA Identification Technique and RST Control of a Hybrid Indirect Matrix Converter with a Flying Capacitor Three Level Inverter in Power Active Filtering Application

The present paper deals with RST controller using implementation of neural architectures to control power electronics systems dedicated to power quality improvement in a distribution grid. We present a technique for designing a robust RST controller, The computation of the controller is used to enhance the control a Hybrid Indirect Matrix Converter with a flying capacitor three level inverter (HIMC) coupled to the power grid (PG) by an RL filter, the synthesizing of this RST controller is formulated through open and close loop. Artificial neuronal network (ANN) identification technique is used to define/extract this disturbance. Simulation results by MATLAB, Simscap/sim power system code shows the effectiveness of the proposed method.

Circulating Current Control for the Modular Multilevel Matrix Converter Based on Model Predictive Control

In this work, a continuous-control-set model predictive control (CCS-MPC) strategy, with a saturation scheme for protection, is presented for regulating the circulating currents of a modular multilevel matrix converter (M3C). The proposed approach is based on a state-space model of the M3C and allows protection and better utilization of the devices through a saturation scheme, which directly limits the arm currents and cluster output voltages by integrating the corresponding bounds as constraints of the CCS-MPC formulation. In order to solve the inherent optimization problem associated with the CCS-MPC, an active-set algorithm is implemented. Experimental and simulation results from a 27-cell M3C prototype validate the proposed strategy and illustrate the good performance achieved with the methodology presented in this work.

DTC Switching Strategy for Open-end Winding of Induction Machines Fed by a Dual-output Indirect Matrix Converter

This paper deals with the Direct Torque Control (DTC) of Dual Indirect Matrix Converter (DIMC) feeding an open-end winding three-phase Induction Motor (IM). Indeed, the open-end winding topology allows overcoming the main problem of Common-Mode Voltage (CMV) which is responsible of presence of stresses in the motor winding in classical topologies, controlling separately the winding of the three-phases, reducing the voltage stress of the power electronics switches and to decreasing the voltage and current harmonics in each phase. The proposed Dual-output Indirect Matrix Converter generates 18 active voltage space vectors. Whereas, in the proposed algorithm presented in this paper to ensure the control of the proposed topology it is implemented only with two null vectors and six active voltage vectors for each output. It is based on same idea of the space vector pulse width modulation that is applied separately for both converters to ensure the control of their output voltages. Indeed, to ensure the required voltage at each winding the output voltage of the first matrix converter are generated normally and output voltage of the second matrix converter are generated with 180° phase shift. The obtained simulation results prove clearly the overall performance of the control of the studied drive system based on the proposed topology and its control algorithm which may be extended to other drive system application, especially in industrial application where more improved performances are required.