Vector Pulse Width Modulation Technique Research Articles

Hybrid PWM noise cancellation technique to reduce switching losses for two‐segment three‐phase motor

This study proposed a novel method to eliminate the pulse width modulation (PWM) harmonics at a quite low switching frequency for the two-segment three-phase motor. Due to the PWM technique and considerations of switching losses, acoustic noise <20 kHz in the motor drive system is common. By using modified space vector PWM (MSVPWM) technique and interleaved topology with magnetically coupled inductors (MCIs), the proposed novel method is able to remove the first, second, and third order carrier frequency noises from the motor. The MSVPWM is used to eliminate the first and third order carrier frequency harmonics and second order harmonics are reduced by interleaved topology. With this method, the unpleasant acoustic noise <20 kHz could be removed when the switching frequency is selected near 6.7 kHz. The size of MCIs mainly depends on the PWM current harmonics and it is very small compared with inductor-capacitor/inductor-capacitor-inductor filter. Moreover, this method remains to be the control dynamics of the motor without additional inductance for fundamental frequency currents. Finally, the effectiveness of the proposed method is verified by detailed simulation and experimental results.

Highly Reliable Back-to-Back Power Converter Without Redundant Bridge Arm for Doubly Fed Induction Generator-Based Wind Turbine

In this paper, a highly reliable back-to-back (BTB) power converter is proposed for doubly fed induction generator-based wind turbines (DFIG-WTs). When a power switch open-circuit fault is encountered in either the grid-side converter (GSC) or the rotor-side converter (RSC), a four-switch three-phase (FSTP) topology is formed to avoid using redundant bridge arms, which reduces the power circuit complexity and minimizes the conduction and switching losses. A simplified space vector pulsewidth modulation technique is used to eliminate sector identification and complex trigonometric calculations. In addition, the influence of dc-bus capacitor voltage unbalance on the electromagnetic torque is analyzed in detail. The offset current components are calculated, and they are deducted from the reference values in the modified control strategies to suppress the dc-bus voltage deviation. Moreover, the power loss model of a BTB converter is analyzed in detail, and the efficiency study is performed in various post-fault situations. Simulations in MATLAB/Simulink are carried out to verify the performance of a DFIG-WT based on a FSTP BTB converter. Furthermore, the control hardware-in-the-loop setup with RSC and GSC separately simulated in a digital real-time simulator is applied for experimental verification of the proposed control strategy.

Common mode voltage elimination in dual‐inverter‐fed six‐phase open‐end winding PMSM drives with a single DC supply

This paper proposes a space vector pulse width modulation (SVPWM) technique to eliminate common mode voltage (CMV) and common mode current for dual-inverter six-phase open-end winding PMSM motor drive fed from a single DC supply. In such a topology, it is mandatory to eliminate the CMV created by the switching PWM of dual-inverter in order to arrest the circulation of common mode current. Based on vector space decomposition (VSD) theory, the switching states’ combinations which do not produce CMV are identified and a space vector pattern with zero CMV is obtained. Proper space vectors are chosen to synthesise the reference voltage, where the resultant reference voltage is decomposed into two components controlled by two modulators independently. The proposed SVPWM technique is compared with the conventional control by simulation in Matlab/Simulink. The performance of the proposed SVPWM technique is evaluated, and the results show the CMV is successfully eliminated.

Speed Control of an Induction Motor Fed by an Inverter Using dSPACE Controller

This paper presents the design and implementation of Inverter system for driving three phase Induction motor using DSPACE DS1104 controller with the controlling objective space vector pulse width modulation (SVPWM) technique. AC motor drives are commonly used over DC motor drives because of their more advantages. Induction motor is the most commonly used AC motor drive for various industrial and domestic applications. The project will be commenced by a basic understanding of SVPWM inverter, components used in the design and study the mathematical equations of the Induction motor. The performance of SVPWM based Induction motor (IM) in open loop is presented with simulation. Here the hardware implementation of the three phase inverter which is fed to a three phase induction motor driven by DSPACE CP1104 is been implemented.

Fault-Tolerant Operation of DFIG-WT With Four-Switch Three-Phase Grid-Side Converter by Using Simplified SVPWM Technique and Compensation Schemes

In this paper, in response to the open-circuit fault scenario in the grid-side converter (GSC) of doubly fed induction generator-based wind turbines (DFIG-WTs), a fault-tolerant four-switch three-phase (FSTP) topology-based GSC is studied. Compared with other switch-level fault-tolerant converter topologies, fewer switches, less switching and conduction losses, and simpler converter structure are derived. A simplified space vector pulse width modulation (SVPWM) technique is proposed to improve the output current quality and reduce the computational complexity in the control process. Unified expressions of duty ratios for the two remaining healthy bridge arms are obtained. In addition, the three-phase unbalance phenomenon caused by the capacitive impedance in the faulty phase is analyzed from the ac point of view, and a current distortion compensation scheme is illustrated. Furthermore, a dc-bus voltage deviation suppression strategy is proposed to maximize the dc-bus voltage utilization rate and mitigate the damage to the dc-link capacitors. Simulations are carried out in MATLAB/Simulink2017a to demonstrate the validity of the proposed SVPWM technique and compensation schemes in FSTP GSC for a 1.5-MW grid-connected DFIG-WT when different working conditions are considered.

A novel center-tapped transformer based multilevel inverter with common DC source

In this paper, a novel multilevel inverter topology is proposed which uses lesser switches and anti-parallel diodes are eliminated in the circuit configuration of the multilevel inverter. Optimal switching strategy for the inverter using three different Space Vector Pulse Width Modulation (SVPWM) techniques is analyzed based on the power quality indices. The proposed model is simulated and tested using MATLAB/Simulink. Owing to the switching techniques used the harmonic content at the output of the inverter is mitigated which results in a lesser value of total harmonic distortion. Reduced number of power electronic switches results in lesser power loss. The performance of the proposed system is validated with simulation results of conventional multilevel inverters and pulse width modulation control methods. The results for various performance parameters such as efficiency, switching loss, voltage magnitude, and total harmonic distortion are analyzed.

Direct grid‐side current model predictive control for grid‐connected inverter with LCL filter

On control of the grid-connected inverter (GCI) with LCL filter, the inverter-side current model predictive control is adopted conventionally. The ultimate grid-side current is controlled indirectly by control of inverter-side current. The ideal scenario is that grid-side current is directly controlled. However, the conventional control model is complicated and the calculation is heavy. This study proposed a novel direct grid-side current model predictive control (GSC-MPC) for GCI with LCL filter. Based on timing coordination of both forward and backward difference methods, a direct connection is established between the grid-side output current and the inverter-side output voltage. Meanwhile, a proper mathematical model is built for an improved model predictive control. The exact required voltage vector in the next sampling interval is predicted and calculated by this model. The output optimal voltage vector is modulated by space vector pulse width modulation technique to control the inverter. Furthermore, the proposed GSC-MPC is rather robust to parameter variation. Simulation and experimental results present that the proposed GSC-MPC can improve the current control performance effectively for GCI with LCL filter.

Dynamic Simulations of Adaptive Design Approaches to Control the Speed of an Induction Machine Considering Parameter Uncertainties and External Perturbations

Recently, the Indirect Field Oriented Control (IFOC) scheme for Induction Motors (IM) has gained wide acceptance in high performance applications. The IFOC has remarkable characteristics of decoupling torque and flux along with an easy hardware implementation. However, the detuning limits the performance of drives due to uncertainties of parameters. Conventionally, the use of a Proportional Integral Differential (PID) controller has been very frequent in variable speed drive applications. However, it does not allow for the operation of an IM in a wide range of speeds. In order to tackle these problems, optimal, robust, and adaptive control algorithms are mostly in use. The work presented in this paper is based on new optimal, robust, and adaptive control strategies, including an Adaptive Proportional Integral (PI) controller, sliding mode control, Fuzzy Logic (FL) control based on Steepest Descent (SD), Levenberg-Marquardt (LM) algorithms, and Hybrid Control (HC) or adaptive sliding mode controller to overcome the deficiency of conventional control strategies. The main theme is to design a robust control scheme having faster dynamic response, reliable operation for parameter uncertainties and speed variation, and maximized torque and efficiency of the IM. The test bench of the IM control has three main parts: IM model, Inverter Model, and control structure. The IM is modelled in synchronous frame using d q modelling while the Space Vector Pulse Width Modulation (SVPWM) technique is used for modulation of the inverter. Our proposed controllers are critically analyzed and compared with the PI controller considering different conditions: parameter uncertainties, speed variation, load disturbances, and under electrical faults. In addition, the results validate the effectiveness of the designed controllers and are then related to former works.

Experimental analysis of various space vector pulse width modulation (SVPWM) techniques for dual three-phase induction motor drive

Experimental analysis of various space vector pulse width modulation (SVPWM) techniques for dual three-phase induction motor drive

A Modified Space Vector PWM Approach for Nine-Level Cascaded H-Bridge Inverter

This paper presents a modified space vector pulse width modulation (MSVPWM) technique for nine-level cascaded H-bridge (CHB) inverter. Based on a modular structure and absence of capacitor balancing problems, CHB inverter topology is preferred. Nowadays, space vector PWM (SVPWM) control scheme has achieved higher attention among different PWM techniques. In general, SVPWM method is realized based on disintegrating higher-level hexagons into a number of two-level hexagons. Compared to conventional SVPWM technique, the proposed MSVPWM technique reduces the computational burden and memory requirement involved in the realization of nine-level SVPWM. This is achieved by reducing the number of two-level hexagons without losing the inverter output voltage profile. Also a further modified space vector pulse width modulation technique is presented, which greatly reduces the computation efforts. The proposed SVPWM techniques are applied to a nine-level CHB inverter by using MATLAB/SIMULINK software tool and are compared with carrier-based sinusoidal pulse width modulation (SPWM) technique to validate the proposed techniques. The proposed SVPWM schemes produce lower harmonic distortion and higher DC bus utilization compared to SPWM technique. To verify the practicality of the proposed SVPWM techniques, experimental results are presented on nine-level CHB inverter.

Three phase voltage source inverters with grid connected industrial application

The grid-connected issue is one of the major problems in the field of Power Electronics. In this paper, the Three Phase Voltage Source Inverter (VSI) is controlled by a Space Vector Pulse Width Modulation (SVPWM) Technique. SVPWM control technique and Park transformation, the managed inverter control system to convert input DC power into AC power, stabilize the output voltage and current, and feeds the excess power to the utility grid can be achieved by controllers. Usually, the grid source contains higher level of harmonics. To analyze the harmonics, nonlinear load is connected externally in the point of common coupling. The main aim of this paper is to modeling, simulation and experimental study of the three-phase grid connected inverter. By using the control algorithm, the grid sides Total Harmonics Distortion (THD) are controlled to the 1.54% for 800V DC as per the IEEE standard. The stimulation results such as AC output voltage and current, inverter system power flow, and grid disturbances detection signals, proves the effectiveness of the developed control algorithm. The control algorithms to makes the for this inverter outputs is pure sinusoidal.

Design of Hybrid Solar Wind Energy System in a Microgrid with MPPT Techiques

&lt;p&gt;DC Microgrid is one feasible and effective solution to integrate renewable energy sources as well as to supply electricity. This paper proposes a DC microgrid with enhanced Maximum Power Point Tracking (MPPT) techniques for wind and solar energy systems. In this paper, the PV system power generation is enhanced by introducing a two-model MPPT technique that combines incremental conductance and constant voltage MPPT algorithms. Also, for the Wind Energy Conversion System (WECS) with pitch angle controlling technique, an Optimal Power Control MPPT technique is added. The Space Vector Pulse Width Modulation technique is introduced on grid side converter to improve the supply to the grid. The performance of proposed system is analyzed and the efficiency obtained with these methods is enhanced as compared with the previous methods.&lt;/p&gt;

A cloud system model employing random space vector pulse width modulation for noise reduction in VSI fed induction motor

Noise reduction at the specific frequency of the line voltage of two level three phase voltage source inverter (VSI) fed induction motor (IM) is dealt in this paper, and the paper aims to develop a new PWM called random space vector pulse width modulation technique (RSVPWM) for reducing noise on line voltage and as well is applied for modeling in cloudsystems. The developed Random SVPWM combines RPWM and Space vector modulation (SVPWM) technique, the paper also investigates the three-phase VSI fed IM and its noise behavior along with noise reduction for cloud system. The proposed method includes a gap in the spectrum of line voltage at selective frequency in human hearing range and as well employed in cloud systems. Therefore, unlike conventional RPWM techniques, switching periods are determined based on the position of rotary reference vector. This work on comparison with other PWM techniques such as sine PWM, RPWM and SVPWM, performs in a better manner. Among all PWM method the proposed RSVPWM generate higher voltages with low total harmonic distortion for VSI fed IM and as well for the considered cloud system models. The proposed RSVPWM achieves less line voltage noise (10.4 dB at lower modulation range and 9 dB at higher modulation range), which proves its effectiveness. The simulation and experimentation is carried out for the full range of switching frequency of 1–20 kHz. The modulation method can be used in both open- and closed-loop IM drive such as V/F and vector control. The above method is applied for both IM and considered cloud system problems.

Control of a converter system for an asymmetrical parameter type two-phase induction motor drive operating in motoring and generating modes

The control of a converter system is presented and discussed for an asymmetrical parameter type two-phase induction machine drive that is operating in motoring and generating modes. The proposed system consists of back-to-back voltage source converters. For a machine side, a three-leg voltage source converter provides both unbalanced and balanced two-phase output voltages with a scalar V/F control based on a carrier space vector pulse width modulation (SVPWM) technique. For a front end, a single-phase AC/DC doubled voltage converter with hysteresis current control is used to keep DC-link voltage constant, thus resulting in a bi-directional power flow operation for the motoring and generating modes. A closed-loop design for the DC-link voltage is fully given and also included is a review of carrier-based SVPWM for two-phase three-leg VSI. The proposed drive system was both simulated using MATLAB/SIMULINK and implemented on digital microcontrollers. The comparative performance evaluation of the whole system between balanced and unbalanced two-phase voltages for the machine is given. The simulation and experimental results show that the unbalanced phase voltage offers better performance for the whole system.

Field-Oriented Control of Energy-Regenerative Electromagnetic Slip Coupling

Electromagnetic slip coupling (EMSC), like other contactless transmission devices, has lots of advantages over contact transmissions such as clutch function, continuous speed regulation, and no mechanical wear. Nevertheless, the EMSC has inherent slip energy especially under the large-slip condition, which leads to low efficiency. A novel energy-regenerative EMSC was developed including wound-type EMSC and the energy-regenerative apparatus for slip energy recovery. To improve recovery efficiency of the EMSC, the field-oriented control strategy was proposed. In this case, the mathematical model of EMSC under synchronously rotating coordinate system was constructed and verified by experiment. Since direct-axis component and quadrature-axis component of current in three-phase windings of the EMSC are coupled, the feed forward decoupling control approach was employed. Space vector pulse width modulation technique was utilized to eliminate harmonic components of current in three-phase windings. Simulations and experiments were carried out to validate the proposed control strategy. The results showed that the voltage and current in three-phase windings were almost in-phase, the current only contained few of harmonic components, and slip energy of the EMSC decreased by 82.5%. In conclusion, the field-oriented control strategy is conducive to recycle the slip energy of the EMSC efficiently.

FPGA-Based Space Vector Pulse Width Modulated Single-Phase to Three-Phase Converter

ABSTRACTConversion of single-phase power supply into three-phase power supply has always been a commercial approach. There is an ever-increasing demand of high-speed electrical machines for a wider range of applications. This paper presents a single-phase to three-phase converter which can generate high frequency output voltage in a single stage to drive high-speed induction motor. A modified space vector pulse width modulation (PWM) technique has been implemented to reduce the total harmonic distortion factor in the output of the converter. In order to generate approximately sinusoidal three-phase output, genetic algorithm has been used as a mathematical tool to estimate the switching angles of different devices in the converter. Detailed design and simulation analysis is presented for single-phase to three-phase converter-fed induction motor drive. A laboratory prototype of the proposed converter is developed through Xilinx field programmable gate array. Test results are presented to validate the proposed design and simulated results of the system.

Stability Study of Output Voltages of Two-Stage PV System Based Three Levels Inverter

This paper presents an algorithm of regulation of AC voltage of photovoltaic conversion system composed by PV generator-boost converter-three phases three levels inverter for stand-alone application without introduced any system to regulate the fluctuation of the DC bus. The maximum power point tracking based on the “perturb & observe” (P&O) approach as a control strategy of a boost DC-DC converter is applied. In order to get the best AC voltage waveform, the simplified space vector pulse width modulation technique is used in this paper. To maintain the two capacitors voltages of DC bus equal, the redundant vectors of space vector diagram of three levels inverter are used. Without any system to regulate the fluctuation of the DC bus and to get a stable output inverter voltage, authors in this paper propose a proportional regulator of inverter modulation index. A theoretical analysis with a complete simulation of the system with different profiles of irradiance is presented to prove the excellent performance of the proposed technique.

Power Control With Z-Source Converter Based Unified Power Flow Controller

In this paper, we propose a Z-source converter (ZSC)-based unified power flow controller (ZSC-UPFC) to enhance power control for long transmission lines. As a multifunctional controller, the UPFC has been adopted to regulate both the active and reactive power flows in transmission lines and to control the AC bus voltage. A recently proposed converter topology, ZSC, uses a Z-network on its DC side to support the desired AC output voltage. The proposed ZSC-UPFC configuration places a Z-network between the dc-link capacitor and the series converter to boost the series converter DC voltage. The integration of Z-network provides the desired converter voltage even with reduced dc-link capacitor voltage setting. We develop a detailed three-phase model for the proposed ZSC-UPFC by modeling the converter operation with switching functions, which are generated by the space vector pulse width modulation (SVPWM) technique. We conduct linear analysis on the D-Q model as well as extensive transient simulation (based on a detailed nonlinear three-phase model) to evaluate the performance of the overall system with the proposed ZSC-UPFC configuration. Our simulation results demonstrate the effectiveness of ZSC-UPFC: 1) The series converter provides the series compensation in a long transmission line with Z-network, and 2) the shunt converter maintains a constant dc-link capacitor voltage and provides reactive power support for the AC bus.

A Novel Approach for Space Vector Based PWM Algorithm for Diode Clamped Three level VSI Fed Induction Motor Drive

&lt;p&gt;Performance of a voltage source inverter depends on pulse width modulation algorithms. Various algorithms exist for conventional space vector as well as space vector based bus clamped pulse width modulation for multilevel inverter in the literature. In this paper appropriate region selection algorithm for conventional space vector pulse width modulation (CSVPWM) and bus clamped pulse width modulation (BCPWM) techniques are proposed for diode clamped three level voltage source inverter. The proposed techniques are implemented on a three level voltage source inverter fed induction motor drive for open loop operation. The schemes are simulated in MATLAB/SIMULINK environments. The merit of proposed region selection algorithm is tested and verified through simulation result. Further performance comparisons between SVPWM and BCPWM for different modulation index are discussed. &lt;/p&gt;

Sensorless Control of Late-Stage Offshore DFIG-WT with FSTP Converters by Using EKF to Ride through Hybrid Faults

A hybrid fault scenario in a late-stage offshore doubly-fed induction generator (DFIG)-based wind turbine (DFIG-WT) with converter open-circuit fault and position sensor failure is investigated in this paper. An extended Kalman filter (EKF)-based sensorless control strategy is utilized to eliminate the encoder. Based on the detailed analysis of the seventh-order dynamic state space model of DFIG, along with the input voltage signals and measured current signals, the EKF algorithm for DFIG is designed to estimate the rotor speed and position. In addition, the bridge arm open circuit in the back-to-back (BTB) power converter of DFIG is taken as a commonly-encountered fault due to the fragility of semiconductor switches. Four-switch three-phase (FSTP) topology-based fault-tolerant converters are employed for post-fault operation by considering the minimization of switching losses and reducing the circuit complexity. Moreover, a simplified space vector pulse width modulation (SVPWM) technique is proposed to reduce the computational burden, and a voltage balancing scheme is put forward to increase the DC-bus voltage utilization rate. Simulation studies are carried out in MATLAB/Simulink2017a (MathWorks, Natick, MA, USA) to demonstrate the validity of the proposed hybrid fault-tolerant strategy for DFIG-WT, with the wind speed fluctuation, measurement noises and grid voltage sag taken into consideration.