Direct Space Vector Modulation Research Articles

A Three-Level Neutral-Point-Clamped Converter Based Standalone Wind Energy Conversion System Controlled with a New Simplified Line-to-Line Space Vector Modulation

Wind power systems, which are currently being constructed for the electricity worldwide market, are mostly based on Doubly Fed Induction Generators (DFIGs). To control such systems, multilevel converters are increasingly preferred due to the well-known benefits they provide. This paper deals with the control of a standalone DFIG-based Wind Energy Conversion System (WECS) by using a three-level Neutral-Point-Clamped (NPC) converter. The frequency and magnitude of the stator output voltage of the DFIG are controlled and fixed at nominal values despite the variable rotor speed, ensuring a continuous AC supply for three-phase loads. This task is achieved by controlling the DFIG rotor currents via a PI controller combined with a new Simplified Direct Space Vector Modulation strategy (SDSVM), which is applied to the three-level NPC converter. This strategy is based on the use of a line-to-line three-level converter space vector diagram without using Park transformation and then simplifying it to that of a two-level converter. The performance of the proposed SDSVM technique in terms of controlling the three-level NPC-converter-based standalone WECS is demonstrated through simulation results. The whole WECS control and the SDSVM strategy are implemented on a dSPACE DS 1104 board that drives a DFIG-based wind system test bench. The obtained experimental results confirm the validity and performance in terms of control.

Bidirectional PWM Converter to Interface AC Part to DC Microgrid with Neutral Potential Balancing

This research presents a description of a bidirectional pulse width modulated converter that functions as a rectifier by using the direct power control strategy and space vector modulation technology. In contrast to the voltage-oriented control strategy, this method minimises the number of internal current loops and requires more tuning. While functioning as an inverter, it applies the space vector modulation technique as well. The approach, on the other hand, is not the same as rectifiers since it calculates the duty ratio of the neighbouring voltage vectors in each small triangle that is generated in each sector that has a period of 60 degrees. In both situations, the neutral point potential has been brought back into equilibrium.

Modeling, design and analysis of direct space vector modulation technique based three-phase matrix converter for different loads

This paper presents the modeling, design and analysis of Three Phase Matrix Converter (TPMC) using Direct Space Vector Modulation technique for the purpose of generation of gate pulses to the switches of the matrix converter. In this paper TPMC with different loads of resistive, Resistor- Capacitor (RC), Resistor-Inductor (RL) has been analyzed. TPMC converts Alternating Current (AC) input power to AC output power directly without the aid of DC link in between the conversion making the availability of the input power directly at the output without intermediate stage. The proposed TMPC with Space Vector Modulation technique possess several advantages compared with the convention converters & Sine Pulse Width Modulation (SPWM) technique. Any distortion or fluctuation in the input side of the converter can be easily depicted at the output side of the converter directly. The proposed topology has been implemented in the MATLAB/SIMULINK software and the desired results of the converter topology has been verified.

Processor in the Loop Comparative Study of Indirect Rotor Field Oriented Control, Direct Self Control, Direct Torque Control and Space Vector Modulation Based Direct Torque Control for Induction Motor Drives

This work proposes a design and implementation, using Processor In the Loop technique, of several control strategies of the induction motor. Therefore, this paper offers a validation, by experimentation, of Direct Self Control, Direct Torque Control and its variants, Space Vector Modulation based Direct Torque Control and Indirect Rotor Field Oriented Control. These control strategies are also compared by waveforms quality, switching frequency and complexity of the algorithms running in an actual Digital Signal Processor. For code generation and algorithm validation, MATLAB/Simulink R2017b and Code Composer Studio are used. For implementation, LAUNCHXL-F28069M development board, based on TMS320F28069 from Texas instruments, is chosen. Results of this comparative study, using Processor In the Loop technique, show that Space Vector Modulation based Direct Torque Control strategy offers the best performances compared to the other Direct Torque Control strategies; and it is, in addition, less complex than the Indirect Rotor Field Oriented Control strategy.

Direct Space Vector Modulation with Novel DC-Link Voltage Balancing Algorithm for Easy Software Implementation of Three-Phase Three-Level Converter

The present paper proposes a direct space vector modulation and novel balance algorithm for easy software application of three-level converters which operate in three-phase. In the case of the conventional space vector modulation, to get the on-state times of the switches, the dwell times of the three nearest stationary vectors, which are obtained after sector and region selection algorithms, should be rearranged. These processes, therefore, contain diverse conditional statements and complicated calculations such as inverse trigonometric functions and square roots. However, the burden of the software application of the proposed algorithm is greatly reduced by not using the sector selection algorithm, the region selection algorithm, and the on-state time allocation process as the proposed modulation can directly control the switch on-state time. In a three-level topology, it is required to balance top and bottom capacitor voltages because the DC-link voltage is composed of two capacitor voltages; the unbalanced voltage of each DC-link capacitor causes the overvoltage of the switching devices. Thus, the DC-link voltage balancing algorithm is proposed, and it is also very simple and effective without additional circuits because it controls the switch on-state time directly as well. The 5-kW prototype proved the validity of the proposed algorithm with its feasibility.

Feedback linearization associated to a sliding mode controller for an operating with unity power factor of induction motor fed by matrix converter

In order to achieve a high performance and to ensure an operation with a unit power factor with respect to imposed reference signals, the input–output feedback linearization technique with a sliding mode controller was proposed to control the induction motor fed by matrix converter drive system. In addition, the direct space vector modulation strategy is adopted to control the matrix converter to minimize the switching losses. On the other hand, a damped input filter has been used to reduce the harmonic total distortion rate injected to the grid. Moreover, the topology and the optimization method for parameter calculation of the input filter are also clarified. The robustness of the proposed control strategy for the drive system was tested and validated by a simulation study.

Minimization torque ripple for SRM based on flux linkage partition in DB-DTFC

This paper proposes a novel deadbeat torque and flux control (DB-DTFC) to reduce torque ripple for switched reluctance motor (SRM). DB-DTFC combines the advantages of direct torque control (DTC) and space-vector modulation (SVM). DB-DTFC leads current vector control into DTC in order to find the equation between torque and current through deadbeat prediction theory i.e. a beat reaches a given point. In addition, the deadbeat calculation module here is similar to that of permanent magnet synchronous motor. Based on dq0 reference frame of SRM, the most suitable dq0 axis current of next moment corresponding to different torque errors is calculated and predicted. According to the calculated dq0 axis current, the optimal space voltage vectors can be selected to reduce torque ripple. In order to verify the effectiveness and correctness of the proposed scheme, DB-DTFC is verified and compared with the DTC-SVM by simulation.

Direct space vector modulation for matrix converter fed dual star induction machine and neuro-fuzzy speed controller

This paper presents the modeling, design, and simulation of an adaptive neuro fuzzy inference strategy (ANFIS) for controlling the speed of the Double Star induction Machine (DSIM), the machine is fed by three phase direct matrix converter which makes directly AC-AC power conversion is modeled using Direct Space Vector Modulation technique(DSVM) for direct matrix converter. Double star Induction motor is characterized by highly non-linear, complex and time-varying dynamics and inaccessibility of some of the states and outputs for measurements. Hence it can be considered as a challenging engineering problem in the industrial sector. Various advanced control techniques has been devised by various researchers across the world. Some of them are based on the neuro-fuzzy techniques. The main advantage of designing the ANFIS coordination scheme is to control the speed of the DSIM to increase the dynamic performance, to provide good stabilization. To show the effectiveness of our scheme, the proposed method was simulated on an electrical system composed of a 4.5 kW six-phase induction machine and its power inverter. Digital simulation results demonstrate that the deigned ANFIS speed controller realize a good dynamic of the DSIM, a perfect speed tracking with no overshoot, give better performance and high robustness.

Decoupling Controller Design and Controllable Regions Analysis for the Space Vector Modulated Matrix Converter-Unified Power Flow Controller in Transmission Systems

The flexible alternating current transmission systems (FACTS) devices are essential components of the transmission system to enhance the controllability and elevate the transfer capacity of the network. The unified power flow controller is known as the most versatile device in the FACTS family. This work studies a distinctive unified power flow controller (UPFC) structure based on the direct matrix converter to regulate the active and reactive power in a transmission system. In contrast to the conventional UPFC, there is no requirement for a bulky energy storage element in this structure. This results in various benefits including: decreased system volume, improved efficiency, prolonged lifetime, reduced maintenance and removal of the DC-link control. The full power controllable regions are analyzed and graphically obtained for the MC-UPFC, which facilitates the selection of proper UPFC ratings. The working principles and a model of the MC-UPFC are put forward and discussed, followed by explanations of direct space vector modulation (SVM) for this application. Based on the SVM modulation scheme, PID controllers are developed to control power flows in a double-line transmission system. In addition, decoupling controllers are derived by feeding back the coupling components into controllers. The numerical simulation results for a double-line transmission system corroborate the feasibility and effectiveness of the proposition.

Decoupled indirect duty cycle PWM technique with carrier frequency adjustment for a matrix converter

The conventional sinusoidal pulse width modulation (SPWM) and the space vector PWM (SVPWM) switching techniques are widely used for power converters due to their ability to control the harmonic content of the output voltage. The most popular PWM techniques used in matrix converters are direct space vector modulation (DSVM) and indirect space vector modulation (ISVM). Since these techniques are complex and difficult to implement, there is demand for a PWM technique with minimum computation to operate matrix converters continuously. In this paper, decoupled indirect duty cycle (DIDC) PWM technique is proposed for the conventional matrix converter (CMC). This technique eliminates the duty cycle computations required for every switching period. In addition, the carrier frequency adjustment technique (CFAT) is proposed to improve the quality of both output voltages and input currents. A MATLAB-Simulink-based simulation proves the efficiency of the proposed algorithms, and an experimental setup is developed to validate them.

A DSVM Method for Matrix Converters to Suppress Common-mode Voltage With Reduced Switching Losses

This paper proposes a direct space-vector modulation (DSVM) method that can reduce the common-mode voltage (CMV) as well as the switching losses for matrix converters in a high voltage transfer ratio. Even though the previous DSVM improvements can reduce the CMV peak value to 42%, compared to the conventional DSVM method, they incur high switching losses. The DSVM method proposed in this paper provides the same CMV peak value as previous methods with lower switching losses. The switching losses are theoretically analyzed through the accumulated switched voltage in a switching period and compared to those of previous methods. Simulation and experimental results are given to verify the input/output waveforms, CMV reduction, and lower switching losses of the proposed DSVM method.

Voltage compensator based on a direct matrix converter without energy storage

The objective of this study is to present a voltage compensator based on a matrix converter without energy storage, which can cope with common power quality problems presented in power distribution systems. The proposed scheme acquires from the grid the necessary energy during the disturbance, which eliminates the drawbacks imposed by the use of a dc-link and the need of energy storage components. A matrix converter study under unbalanced input voltage conditions is exposed, as well as a detailed explanation of the proposed modified direct space vector modulation (MDSVM). It has been verified that even when the supply voltage exhibits unbalanced conditions and harmonic distortion, the control strategy does not exhibit difficulties to synthesise the compensation voltages, provided the restrictions imposed by the formulation are fulfilled. Numerical simulations and experimental results from a laboratory scale prototype are presented to validate the performance of the compensator.

Performance Analysis of a DTC and SVM Based Field-Orientation Control Induction Motor Drive

<p>This study presents a performance analysis of two most popular control strategies for Induction Motor (IM) drives: direct torque control (DTC) and space vector modulation (SVM) strategies. The performance analysis is done by applying field-orientation control (FOC) technique because of its good dynamic response. The theoretical principle, simulation results are discussed to study the dynamic performances of the drive system for individual control strategies using actual parameters of induction motor. A closed loop PI controller scheme has been used. The main purpose of this study is to minimize ripple in torque response curve and to achieve quick speed response as well as to investigate the condition for optimum performance of induction motor drive. Depending on the simulation results this study also presents a detailed comparison between direct torque control and space vector modulation based field-orientation control method for the induction motor drive.</p>

Equivalent matrix structure modelling and control of a three‐phase flying capacitor multilevel inverter

In this study, an equivalent matrix structure of three-phase flying capacitor multilevel inverters (FCMIs) is developed. This structure is obtained by using a switching function for each voltage level. For one switching function, there is more than one combination of gate signal to produce each output voltages. Hence (3 n ) switching functions are defined for all switch combinations of the output voltage and their corresponding switch states. Therefore the modulation strategy of a three-phase FCMI is obtained in two steps. Firstly, the direct space-vector modulation of the matrix converter is used to compute the switching functions. The gates signals of the three-phase FCMI can be calculated by inversing the modelling part. In this work, the direct space-vector multilevel modulation based on the use of 2 n different three level functions called modulation functions is presented. Using this approach, the modulation strategy of a three-phase FCMI is designed without using a Park transform. To validate the effectiveness of the equivalent matrix structure modelling and control, simulation results are given for nine-level FCMI. Moreover, experimental results are given for a three-level neutral point clamped (NPC) converter prototype laboratory.

Applying Reduced General Direct Space Vector Modulation Approach of AC–AC Matrix Converter Theory to Achieve Direct Power Factor Controlled Three-Phase AC–DC Matrix Rectifier

This paper presents a novel approach to achieve both tight dc voltage regulation and direct power factor control by applying general direct space vector modulation (G-SVM) of matrix converter theory to a three-phase ac–dc matrix rectifier. The reduced form of G-SVM and the derivation of the three-phase ac–dc matrix rectifier from a three-phase ac–ac matrix converter are described and theoretically justified. The proposed matrix converter features intrinsic buck conversion, tight output voltage regulation via modulation, inherent capability of four-quadrant operation, elimination of the bulky storage component on the dc bus, and sinusoidal input current. Moreover, the reduced G-SVM-controlled three-phase ac–dc matrix rectifier can achieve leading, lagging, or unity input power factor by simple and direct control of the input current displacement angle. This significantly benefits the potential application of the reduced G-SVM-controlled three-phase matrix rectifier to automotive, aircraft, ship, and other three-phase standby dc supplies. In these applications, the unity power factor control is indispensable when the dc load widely changes. Simulated and experimental verification for this strategy has been presented and discussed in this paper.

Unity Power Factor at the Power Supply Side for MATRIX Converter Fed PMSM Drives

To reduce the high harmonic components at the main power supply current and to improve the input voltage distortion for matrix converter, design of input filters characteristics for matrix converter system is very important. Also, the input filter can be applied to the near unity power factor operation at the input side. It can be used to improve the power quality of the input current. This paper represents a direct space vector modulation (SVM) method and introduces switching patterns for SVM method and then design of input filter to compensate the power factor is analyzed. Simulation results with inductive load (RL) and Permanent-magnet synchronous motor (PMSM) are shown to validate the effectiveness of the proposed method. DOI: http://dx.doi.org/10.11591/ijece.v4i1.4813

Performance Analysis of DTC-SVM Sliding Mode Controllers-Based Parameters Estimator of Electric Motor Speed Drive

This paper is concerned with a framework which unifies direct torque control space vector modulation (DTC-SVM) and variable structure control (VSC). The result is a hybrid VSC-DTC-SVM controller design which eliminates several major limitations of the two individual controls and retains merits of both controllers. It has been shown that obtained control laws are very sensitive to variations of the stator resistance, the rotor resistance, and the mutual inductance. This paper discusses the performances of adaptive controllers of VSC-DTC-SVM monitored induction motor drive in a wide speed range and even in the presence of parameters uncertainties and mismatching disturbances. Better estimations of the stator resistance, the rotor resistance, and the mutual inductance yield improvements of induction motor performances using VSC-DTC-SVM, thereby facilitating torque ripple minimization. Simulation results verified the performances of the proposed approach.

Nonlinear Speed Controller Supported by Direct Torque Control Algorithm and Space Vector Modulation for Induction Motors in Electrical Vehicles

Energy mode functions and their inverse signal dynamics can be used for the design of controllers in classical control algorithms, which use the error signals of related system parameters in general mode. Different from this common approach, Lyapunov function-based controller design is preferred and motor mechanical speed parameter is incorporated into the control operation in this study. The results of the experimental studies conducted for this study prove that when both electrical and mechanical parameters of the system are taken into consideration, the proposed controller, nonlinear speed controller supported by direct torque controller and space vector modulation, performs better than classical controllers and can be realized successfully. DOI: http://dx.doi.org/10.5755/j01.eee.19.6.1970

An Effective Direct-SVM Method for Matrix Converters Operating With Low-Voltage Transfer Ratio

This paper focuses on the common-mode voltage reduction and the power quality of matrix converters for a low-voltage transfer ratio of less than 0.5 by the direct space vector modulation (DSVM) method. The principles of selecting suitable switching configurations based on new space vector sectors are described, and an entire switching table for the new control strategy is developed. The matrix converter with the proposed method reduces peak-to-peak common-mode voltage remarkably. The new DSVM method has advantages over the conventional DSVM method, such as lower total harmonic distortion of line-to-line output voltage and a reduction in switching loss by a minimum number of switching commutations. The proposed DSVM method can be easily implemented in software. Simulation and experimental results are shown to verify the effectiveness of the proposed DSVM method.

High Performance of Matrix Converter Fed Induction Motor for IPF Compensation by Using New DSVM Method

In the matrix converter (MC) system to improve the input current quality with low harmonic components, as well as to reduce the input voltage distortion supplied to the MC by using input filters. The major consequence of the paper is about the inter harmonics appearing in the induction motor drive.. In this paper, we propose a new direct space vector modulation (DSVM) method to achieve the required displacement angle between the input voltage and input current of the MC. The paper illustrates the various inter harmonics elimination methods of SVM inverter fed drive and the associated drawbacks. The drawbacks are eliminated by using New DSVM method instead of SVM method in matrix converter fed induction motor drive. A new switching strategy is introduced based on the maximum compensated angle. Then, power factor compensation algorithms using the new DSVM method to achieve the maximum IPF. In which Compensation algorithm is subsequently proposed using a proportional-integral controller to overcome drawbacks presented in compensation algorithm of SVM method. Simulation and experimental results are shown to validate the effectiveness of the proposed compensation algorithms. Keywords: Direct space vector modulation (DSVM) method, induction motor drive, inter-harmonics, input filter, matrix converter (MC).