Space Vector Research Articles

Optimisation of Torque Ripples in Permanent Magnet Synchronous Motor using Hysteresis Current Controller

This paper’s primary goal is to investigate and analyze how a particular PWM technique enhances the performance of PMSM drives. The objective of the analysis is to reduce torque ripples, which are fluctuations or variations in the motor’s torque output. Reducing these torque ripples involves combining the Hysteresis Control and Space Vector Pulse Width Modulation (SVPWM) techniques. Hysteresis Control is a method that compares the actual value of a parameter (in this case, torque) with a reference value and takes appropriate control actions based on the comparison. SVPWM, on the other hand, is a sophisticated technique used for generating pulse width modulation signals that can control the motor precisely and efficiently. The research findings suggest that combining the Hysteresis Control technique with SVPWM in the PMSM motor drive makes the system more effective and efficient. This combination likely reduces torque ripples, leading to a smoother motor operation. Using both techniques together probably enhances the precision and stability of the motor control system.

Minimization of Common Mode Voltage and Capacitor Voltage Unbalance of 3-Phase 4-Wire 3-Level NPC inverter using 4D-SVM

This paper elucidates the implementation of Four-dimensional Space Vector Modulation (4D-SVM) for reduction of Common Mode Voltage (CMV) and Capacitor Voltage Unbalance (CVU) of 3-phase 4-wire 3-level Neutral Point Clamped inverter (3L-NPCI). CMV and CVU are major drawbacks of neutral point clamped inverter circuit; It leads to affect the performance of inverter in terms of bearing failure, unequal voltage stress across various switching devices, the magnitude of load current increases, increases in total harmonic distortion (THD), tripping of ground fault relays and malfunction of various sensitive electronics and control unit. The 4D-SVM algorithm is developed to reduce the CMV and CVU; with help of the nearest state vector (NSV) control method CMV range is reduced and by proper utilization of large and small vector capacitor voltage unbalance is minimized. 4D-SVM for 3-phase 4-wire 3-level includes 81 switching state vectors with a non-redundant switching concept. This algorithm is implemented without using any trigonometric equations, lookup tables, and angle determinations. This proposed system provides a comprehensive analysis of 4D-SVM for reduction of CMV range and CVU for the 3L-NPCI system. The minimization of CMV and CVU is achieved using MatLab-Simulink and FPGA processor for simulation and experimental results respectively.

Improved Model Predictive Control With Reduced DC-Link Capacitor RMS Current for Back-to-Back Converter-Fed PMSM Drives

A low root mean square (RMS) current flowing through the intermediate DC-link capacitor is always desired in the back-to-back (BTB) voltage source converters (VSCs)-fed motor drive, such that the designed capacitor lifespan can be extended or a lower DC-link size could be the alternative with improved power density. The conventional modulator-based control involves the inherent carrier-based switching operation, and hence the dominant harmonics at carrier frequency multiplier and carrier sideband are introduced into the capacitor current. Therefore, the finite-control-set model predictive control (FCS-MPC) is proposed to optimize the capacitor RMS current. The direct switching pulse generation without using the carrier can give a distinctive capacitor current spectrum and more possible current pulse cancellation between the BTB VSCs can be conveniently achieved through the cost function. Besides, the acceptable grid-current quality and the motor performance are maintained by using a tunable weighting factor. The simulated and experimental results highlight the effectiveness and benefits of the proposed method in terms of 20%-35% capacitor RMS current reduction compared to the synchronous carrier-based space vector pulse-width modulation (SVPWM) scheme and also significant improvements over the distributed predictive manner.

Dynamic Interleaving Strategy to Reduce DC-Link Ripple of Dual Three-Phase Permanent Magnet Synchronous Machine Drives by Using Discontinuous Space Vector Modulation

Dynamic Interleaving Strategy to Reduce DC-Link Ripple of Dual Three-Phase Permanent Magnet Synchronous Machine Drives by Using Discontinuous Space Vector Modulation

Direct electromagnetic force control of linear induction motor with end effects using fuzzy controller

In this article is a present dynamic model of a linen induction motor with end effects, occurs when the electromagnetic system of the motor is open. Instead of the angular speed and electromagnetic torque as a rotation motor, in the linear induction motor we have linear speed and linear electromagnetic force, which are sufficiently influenced by the open electromagnetic system of the primary and secondary elements of the linear motor. The choice of an appropriate control system for a linear induction motor is of particular importance considering the use of this type of motor in manufacturing. There are different types of control schemes for standard rotary motors that have their own advantages and disadvantages. When choosing a motor control scheme, we strive to achieve the following parameters, such as smoothness of regulation, ability to regulate in all four quadrants, accuracy of regulation, range of regulation and last but not least, simplicity of regulation. One such method that meets these criteria for rotary motors is the direct torque control method with space vector modulation. The control system of the linear induction motor proposed in this paper is based on this method, taking into account the open electromagnetic system and the occurrence of the end effects of the linear induction motor. Instead of the angular reference velocity as a rotary motor, in this case we have a linear reference velocity to the input, which is compared to the current linear velocity of the motor. The present paper also uses the vector modulation method by analogy with direct torque control with space vector modulation of the rotary motor. For the conversion of a linear velocity to a linear electromagnetic force, instead of a standard PI controller, it is using a fuzzy controller to convert a linear velocity to a reference electromagnetic force.

Speed control of three-phase induction motor using three-phase matrix converter with space vector modulation technique

The three-phase matrix converter connected to the three-phase induction motor is studied in this paper. Typically, induction motors used in industries and automobiles operate on the electromagnetic induction principle. Due to its numerous benefits, including low cost and maintenance requirements, light weight, great efficiency, and others, a squirrel cage induction motor is employed in this situation. The speed of the induction motor may be changed by altering the voltage and frequency using a V/f control. A three-phase matrix converter is an automated AC-to-AC converter that uses a direct stage of conversion and bi-directional switches. Space vector modulation may be used to control the switches of a matrix converter, and by doing so, improve power factor.

Comprehensive research and analysis on obstacle–singularity–joint limit avoidance of redundant robot

Redundant robots can complete other tasks while performing main task and have excellent motion performance. Although redundant robots have redundancy characteristics, they may still fall into singular configuration or cannot overcome joint limits due to the limitation of their own structure and motion law. Besides, currently, most of the research mainly focus on obstacle avoidance at the end of the robot. So comprehensive study is conducted on avoidance of obstacle, singularity, and joint limit of redundant robot. Firstly, the kinematics model of robot is obtained by D-H matrix method. Space vector distance method is proposed to calculate the position relationship between robot and obstacle, and potential function is constructed. Based on gradient projection method, using the damped generalized inverse and the weighted norm method, the mathematical models of obstacle avoidance, singularity avoidance, and joint limit avoidance are constructed. The simulation results show that the robot can avoid the obstacle in three-dimensional redundant space. At the same time, manipulability and minimum singular value of the robot are always positive. After adding the function of avoiding joint limit, during the whole control process, the motion range of joint angle is reduced and the angular velocity is relatively small, which ensure the motion stability of robot. Namely, the singular configuration and joint limit of robot are avoided. The research is of great significance for practical application of redundant robot.

Improvement of Voltage Quality in a Distribution System by a Novel Simplified Unit Vector Theory

Improvement of Voltage Quality in a Distribution System by a Novel Simplified Unit Vector Theory

PROPAGATION OF VECTOR VORTEX BEAMS EXCITED BY A TERAHERTZ LASER DIELECTRIC RESONATOR

In this paper, analytical expressions for the nonparaxial mode diffraction of a terahertz laser dielectric waveguide resonator are derived. It is assumed that the modes interact with a spiral phase plate. The cases of different topological charges (n) are considered. Also, using numerical simulations, the physical features of emerging vortex beams are studied when they propagate in free space. The Rayleigh-Sommerfeld vector theory is used to study propagation of the vortex laser beams in different diffraction zones excited by the modes of a dielectric waveguide quasi-optical resonator upon incidence on a spiral phase plate. It is shown that the interaction of a spiral phase plate with a linearly polarized EH<sub>11</sub> mode forms a ring (n = 1, 2) due to field structure with an intensity maximum at the center (n = 0). For the azimuthally polarized TE<sub>01</sub> mode, the ring (n = 0) field structure transforms into a field distribution with an intensity maximum at the center (n = 1) and then back to a ring (n = 2). In this case, the phase front of the EH<sub>11</sub> mode beam turns from a spherical shape to a spiral one with one singularity point on the axis, while a region with two singularity points appears off the axis for the phase structure of the TE<sub>01</sub> mode beam.

ПОШИРЕННЯ ТЕРАГЕРЦОВИХ ВИХРОВИХ ЛАЗЕРНИХ ПУЧКІВ У ВІЛЬНОМУ ПРОСТОРІ

Subject and Purpose. Currently, numerous ideas and different methods have been in growth for generating vortex beams — areas of the circular motion of the electromagnetic wave energy flow around the so-called phase singularity points caused by a violation of the wave front topological structure. The purpose of this work is to obtain analytical expressions describing the nonparaxial diffraction of wave modes of the waveguide resonator of a terahertz laser during the wave mode interaction with a spiral phase plate. The resulting vortex beams are examined for their physical features in free space propagation. Methods and Methodology. The Rayleigh-Sommerfeld vector theory is adopted to consider the propagation of vortex laser beams generated by wave modes of the quasi-optical waveguide cavity when interacting with a spiral phase plate in different diffraction zones. Results. For the first time, analytical expressions have been obtained to describe the nonparaxial diffraction of wave modes of the waveguide resonator of a terahertz laser, when resonator modes interact with a spiral phase plate at different topological charges, n. The physical features of the resulting vortex beams were studied in their free space propagation. It has been shown that a spiral phase plate modifies the structure of the linearly polarized EH₁₁ mode so that the original (n=0) intensity profile with the maximum energy at the center turns at n=1 and 2 into a ring-like donut shape with an energy hole in the center. The azimuthally polarized TE₀₁ mode has originally (n=0) a ring-shaped intensity. At n=1, this configuration changes to have the maximum intensity in the center. At n=2, it becomes annular again. In the process, the spherical phase front of the beam of the linearly polarized EH₁₁ mode becomes spiral and have one singularity point on the axis, whereas the phase structure of the azimuthally polarized TE₀₁ mode gains a region with two phase singularity points off the axis. Conclusions. The results of the study can effectively facilitate information transfer in high-speed THz communication systems. They can provide a real platform to perform tasks related to tomography, exploring properties of materials, detecting astrophysical sources, which makes them very promising in modern technologies.

Clarke Circuit Analysis for Space-Vector Ellipse Characterization of Phase-to-Ground Faults in Three-Phase Radial Systems

This work deals with the technique for fault detection and classification in three-phase power systems based on the elliptical trajectory of the voltage space vector on the complex plane. A new approach is presented leading to the derivation of equivalent circuits directly in the Clarke domain where the space vector is defined. A specific methodology is introduced to manage the asymmetrical behavior of single-phase and double-phase faults. In particular, an in-depth analysis is presented for the single-phase-to-ground fault. The proposed equivalent circuits allow straightforward derivation and interpretation of the voltage ellipse for fault characterization. The analytical results are validated through the simulation of a three-phase radial system.

Three-Phase Distortion Analysis based on Space-Vector Locus Diagrams

This work deals with the use of the space vector concept to characterize the harmonic content of a three-phase voltage/current. It is shown that the shape of the trajectory of the space vector on the complex plane (i.e., the locus diagram) provides information about its harmonic content. In particular, it is shown that each harmonic contributes to the locus diagram with a number of lobes depending on the relative angular frequency between the harmonic and the fundamental component. To this aim, the different contributions of positive-sequence and negative-sequence harmonics is explained and put into evidence with specific examples. The expressions for the magnitude and phase of the space vector as functions of the harmonics are derived analytically. Numerical examples are provided to show how the locus diagram can represent a three-phase quantity with positive-sequence and negative-sequence harmonics.

Shunt Active Parallel Filter, Grid Photovoltaic System

This paper introduces a study focused on managing a photovoltaic system connected to the electrical grid. The primary components of this system include solar arrays linked via a DC bus to an inverter situated on the grid side. Fluctuations in solar irradiance and temperature are swift, prompting the integration of maximum power point tracking (MPPT) within the inverter’s control mechanism. The energy produced by the photovoltaic system is fed into the grid. This transfer is achieved through a proficient DC/AC conversion process, wherein the MPPT is integrated into the inverter’s operation to regulate the levels of active and reactive power injected into the grid. The paper also delves into the employment of the Space Vector Modulation (SVM) control technique for the DC-AC inverter. It covers the implementation of a Shunt Active Power Filter (SAPF) with a three-phase four-wire configuration, consisting of four legs and adopting a split capacitor topology. Furthermore, the paper includes an exploration of the instantaneous power theory and the utilization of hysteresis block control for the SAPF. The findings of this study are demonstrated and analyzed using Matlab/Simulink software.

A Hybrid Active Damping Strategy for Improving the Adaptability of LCL Converter in Weak Grid

In a weak grid, the line impedance variation will cause the resonant frequency of the LCL filter to shift towards lower frequencies, thus reducing the quality of the grid-connected current and affecting the power grid stability. To solve this problem, a hybrid active damping strategy with feedforward compensation is proposed for the neutral point clamped (NPC) LCL grid-connected inverter system. In order to reshape the output conductance of the grid-connected system, suppress the resonance spikes of the LCL filter and improve the adaptability of the grid-connected system to the weak grid. A first-order low-pass filter is designed in the grid-connected current loop, and an active damping control of grid-connected current based on a first-order high-pass filter is also proposed. Compared with the conventional capacitive current active damping, no additional sensors are required, and the use of a differential is avoided, which reduces the high-frequency noise. The use of passive resistors is reduced, which reduces the power loss of the grid-connected system. In addition, a point of common coupling (PCC) voltage feedforward strategy based on a low-pass filter is designed to suppress the background higher harmonics at PCC and improve the quality of grid-connected current. In this work, the robustness of the system is analyzed when the parameters of the LCL filter change. Finally, the virtual space vector modulation strategy is used to balance the neutral voltage of the DC bus. Simulation and experimental results show that the control strategy can effectively improve the adaptability of the system to the weak power grid, improve the quality of grid-connected current, and demonstrate strong stability. The THD can be decreased by 0.2% at least, and the improvements are more significant with larger line impedance; the THD is only 2.33% even at 10 mH line impedance.

Hybrid passivity‐based control of a three single‐phase star‐connected unidirectional five‐level rectifier with a space vector pulse‐width modulation algorithm for voltage balance

SummaryThe unidirectional multilevel rectifier has been used in numerous industrial applications due to its reduced active power switches, higher power density, and lower cost compared to conventional bidirectional converters. Recently, the unidirectional five‐level rectifier has been proposed for its lower device stress and the potential for extension to higher levels. However, it adopts a conventional linear proportional integral (PI) control strategy and sinusoidal pulse‐width modulation (SPWM) method, resulting in a complex control structure, particularly for the balance control of the midpoint voltage, and suboptimal dynamic performance. To address this issue and enhance system's large‐scale stability, a hybrid passivity‐based control (PBC) strategy, along with a simplified mathematical model, has been proposed. The hybrid PBC control strategy includes an outer loop active disturbance rejection (ADR)‐PI controller and inner loop PBC controller, providing a simple overall control structure and strong anti‐interference ability. Additionally, a space vector pulse‐width modulation (SVPWM) algorithm has been briefly introduced and applied to further improve the recovery and balance speed of the DC‐side capacitor voltages. Simulation and experiment results have validated the feasibility and effectiveness of the proposed hybrid PBC strategy and the SVPWM algorithm.

Absolute pose estimation of UAV based on large-scale satellite image

Obtaining absolute pose based on pre-loaded satellite images is one of the important means of autonomous navigation for small Unmanned Aerial Vehicles (UAVs) in Global Navigation Satellite System (GNSS) denied environments. Most of the previous works have tended to build Convolutional Neural Networks (CNNs) to extract features and then directly regress the pose, which will fail when solving the challenges caused by the huge viewpoint and size differences between “UAV-satellite” image pairs in real-world scenarios. Therefore, this paper proposes a probability distribution/regression integrated deep model with the attention-guided triple fusion mechanism, which estimates discrete distributions in pose space and three-dimensional vectors in translation space. In order to overcome the shortage of the relevant dataset, this paper simulates image datasets captured by UAVs with forward-facing cameras during target searching and autonomous attacking. The effectiveness, superiority, and robustness of the proposed method are verified by simulated datasets and flight tests.

Implementation of Indirect Field Oriented Control Using Space Vector Pulse Width Modulation for the Control of Induction Motor

For the efficient speed control of three phase Induction motor, the Vector control or Field oriented control (FOC) technique is used for the Voltage source inverter. In implementing FOC the angular position of the rotor flux vector is to be determined. There are two methods (direct and indirect) of vector control for the evaluation of rotor angle. In an Indirect field-oriented control (IFOC) method rotor angle is estimated from slip frequency and rotor frequency without using a sensor (sensors are used in direct FOC) which are achieved in a synchronously rotating frame. IFOC produces high performance in induction motor drives by decoupling rotor flux and torque, so it can be separately controlled by stator direct-axis current and quadrature-axis current respectively, like in a DC motor. The rotor flux orientation method is used for incorporating PI control system using the Space Vector Pulse Width Modulation (SVPWM) technique. The Induction motor drive control generally involves three different PI controllers for torque, speed, and flux respectively. Through the simulation result, varying the load torque, and reference speed is achieved within a few milliseconds, and the behavior of the separately excited DC motor is observed.

Analysis and mitigation of PQ disturbances in grid connected system using fuzzy logic based IUPQC

Renewable energy integration introduces grid instability due to variable and intermittent sources like solar and wind, impacting reliability. This paper provides a thorough discussion of recent advancements and emerging trends in grid-integrated wind energy systems (GIWES) and grid-integrated solar energy systems (GISES). More than 70 research articles have been rigorously assessed and listed the technological and economic challenges. The increase in installations of grid-Integrating systems gives rise to challenges like as grid strain, peak shaving impacts, unpredictability of renewable energy sources (RES), and power quality disturbances. A variety of custom power devices, such as dynamic voltage restorers (DVR), static synchronous compensators (STATCOM), active power filters (APF), and unified power quality conditioners (UPQC), have gained popularity in response to these challenges. Among the various challenges, power quality disturbances, including voltage sag, swell, current and harmonics pose significant issues. To address these disturbances this work present a novel approach utilizing fuzzy logic (FL) to develop multi-feeder interline unified power-quality conditioners (MF-IUPQCs). The MF-IUPQC has three legs and three levels, each of which has four diode-clamped inverters. Switching is carried out through the use of space vector pulse width/duration modulation (SVPWM). Total harmonic distortion (THD) induced by nonlinear loads is reduced by the FLC-based MF-IUPQC, which also improves dynamic performance and offers a smooth DC-link voltage. The proposed control mechanism is implemented using MATLAB/Simulink. The fuzzy-based controller is compared to the industry-standard proportional-integral (PI) controller to determine its efficacy. Among them, the MF-IUPQC based on FLC delivers the smoothest voltage profile and the lowest THD.

Enrollment of Vector in Cardiology and Study of Cardiac Cadence

We have analyzed the application of vectors in cardiology and the way cardiac vector theory analyzes the heartbeat and can explain the entire cardiac conduction vector relationship and the Enthoven equilateral triangle hypothesis. This sheet explains the principles of the electrocardiogram and the interpretation of the waveforms. ECG can be called an electrocardiogram, which is a process of producing electrical activity through repetitive cycles. This diagram shows the voltage and duration of electrical activity by placing electrodes on the skin. Vector cardiography ( VCG) is a procedure that creates a 2D image of the heart's electrical activity by monitoring the spatial location of ECG waves at each successive point in their period. Even in the 21st century, coronary heart disease still represents a serious threat to humans and a major challenge to the scientific community. The most important elements for understanding and interpreting the ECG are the Enthoven triangle and the cardiac vector hypothesis, which have the potential , saving millions of lives when used quickly and appropriately to treat patients.

A simplified space vector modulation for the single-phase active power decoupling quasi-Z-source inverter

The double-line frequency ripple power of the single-phase quasi-Z source inverter (qZSI) will result in a large designed qZS impedance on the dc side, which can be greatly reduced by the coupled-type active power decoupling (APD) method. However, the traditional sinusoidal pulse width modulation (SPWM) for the APD-qZSI needs extravagant APD storage capacitance and may cause abnormal operation under low load conditions. Classical space vector modulation (SVM) has higher flexibility and dc-link voltage utilization, but it cannot be directly applied to the APD-qZSI. In this paper, a simplified SVM method for the coupled-type APD-qZSI is proposed, where the switching time sequence is transformed to carrier-based pulse width modulation, so the shoot-through control of the qZSI is easy to implement. Next, the passive component parameters and normal operation range of the traditional SPWM and the proposed SVM are analyzed and compared. The proposed SVM has a smaller APD storage capacitance but a slightly larger ac side filter inductance. In addition, the decreased current of the APD branch under SVM can help suppress the abnormal operation of the inverter, so the APD-qZSI can operate at a lower load condition. Finally, experimental results validate the effectiveness and superiority of the proposed SVM method.