Multilevel Space Vector Pulsewidth Modulation Research Articles

Sensorless Speed Control for PMSM Based on Multi-Level SVPWM Inverter and MRAS

Permanent Magnet Synchronous Motors (PMSM) are extensively used in the industry owing to their excellent efficiency, low weight/power ratio, and smooth torque with no or minimal ripple. Field Oriented Control (FOC) is a modern and effective approach for closed-loop controlling the speed of PMSM. In this paper, three-level Space Vector Pulse Width Modulation (SVPWM) is proposed for minimizing harmonics in the output voltage inverter. sensorless approaches are performed by using Model Reference Adaptive System (MRAS) which eliminates mechanical uncertainties. Because mechanical sensors increase the cost, size, weight, and wiring complexity, employing PMSM with them is extremely difficult Tuning of Proportional Integral (PI) controller gains is performed by using the Whale Optimization Algorithm (WOA). The results show that the proposed controller enhances the system's performance. In the application of felid-oriented control to a PMSM, with simulation data to back it up the entire system is simulated using the MATLAB/Simulink tool. Index Terms— PMSM, SVPWM, FOC, MRAS, WOA.

A Simplified Multilevel Space Vector Pulsewidth Modulation (SVPWM) Based on Boundary Lines, Including Overmodulation Zone

A Simplified Multilevel Space Vector Pulsewidth Modulation (SVPWM) Based on Boundary Lines, Including Overmodulation Zone

A New Decentralized Space Vector PWM Method for Multilevel Single-Phase Full Bridge Converters

This paper proposes a decentralized control structure and method for a multilevel single-phase power converter using space vector pulse width modulation (SVPWM). The focus of this paper is on the decentralized control structure for the power converter cells that will exchange information with neighboring cells in order to adjust the switching vector and switching time for each cell. In this study, the switching vectors and the corresponding switching times of each cell will be self-determined based on the phase angle of two neighboring cells. Normally, SVPWM applied to the multilevel power converters need complete information about the total cells and cell’s position to build a control algorithm. Meanwhile, a decentralized space vector pulse width modulation (DSVPWM) method is proposed that can be applied to power converters with any number of cells and can be considered as a multilevel SVPWM method. In addition, the decentralized multilevel single-phase power converter has high flexibility with which it is possible to easily adjust the number of active cells, so that the output voltage can be adjusted quickly; this provides the ability to dynamically reconfigure without interrupting the power energy supply process. The proposed control structure and method are effectively verified based on simulation and experimental results. Experimental results are evaluated based on a 9-level single-phase power converter, which has an RL load with rated parameters 220 V/500 W.

Simplified SVPWM-based SoC balancing strategy for three-phase cascaded H-bridge multilevel converter in off-grid energy storage systems

This paper proposes a state of charge (SoC) balancing strategy based on the simplified multilevel space vector pulse width modulation (SVPWM) for cascaded H-bridge multilevel converter (CHMC) in off-grid energy storage systems (ESS). The simplified multilevel SVPWM selects base voltage vectors and mathematically represents the base voltage vectors and their switching state combinations, which will ensure high expansibility and low complexity of the proposed strategy. Base on the simplified multilevel SVPWM, the clustered balancing of the proposed strategy is realized by directly calculating the switching state combinations with an introduced SoC balancing speed factor, while the individual balancing is achieved by using a SoC balancing influence operator. In addition, the “clockwise-counterclockwise circulation” is provided to adjust the sequence of voltage vectors, which reduces the switching loss in ESS. The superior features of the proposed strategy in balancing speed, voltage waveform and efficiency are confirmed by simulations and experiments.

MSVPWM Based-SAPF For Harmonic Mitigation in The Distribution Network Under Unbalanced Condition

Unbalanced input source voltages generate extra current harmonics in addition to non-linear loads which distorts the power quality in the entire power systems. Three-phase multi-level neutral point clamped (NPC) converter based shunt active harmonic filter (SAHF) are used as a solution to overcome problems due to current harmonics. In this work, synchronous reference frame (d-q) algorithm is selected to detect the harmonic current components, Proportional-integral (PI) controller is utilized to ameliorate the storage of energy in the dc-link capacitor and the multilevel space vector pulse width modulation (MSVPWM) strategy determines the switching pulses of NPC inverter. Under balanced input supply voltages condition, the proposed MSVPWM achieved a mitigation of source current THD of 3.58 % as compared to 28.57 % prior to compensation on non-linear load. Furthermore, the MSVPWM technique was compared with and without compensation under unbalanced input source voltages and the results shows that the proposed method achieved reduction in source current THD of 3.96 % as compared to 29.76 % after and before compensation respectively. The proposed MSVPWM based-SAPF model was also compared with conventional SVPWM under balanced and unbalanced input supply voltages conditions. The results show that MSVPWM performed better than CSVPWM. The simulated results obtained by MATLAB/SIMULINK power system environment. All the results for the presented work are within IEEE-519 harmonics standard with non-linear loads under balanced and unbalanced voltages condition.

A Fast Multilevel SVPWM Method Based on the Imaginary Coordinate With Direct Control of Redundant Vectors or Zero Sequence Components

This paper for the first time comprehensively presents a multilevel space vector pulse width modulation (SVPWM) method based on the imaginary coordinate system. This method is probably one of the most efficient methods in fast multilevel SVPWMs. It avoids trigonometric operation, look-up tables and only requires simple logic judgement and arithmetic calculation. A distinct advantage of this method over other coordinate-transformation-based methods is that it does not need to transform from the imaginary coordinate system back to the a-b-c (or α-β) coordinate in order to select the redundant vectors using look-up tables. The redundant vectors or zero-sequence components are directly worked out in the proposed method, e.g., for balancing dc-link capacitor voltages, which avoids identifying the starting vector, vector rotation direction (clockwise or anti-clockwise), vector sequence, etc. as used in conventional methods. This paper entails each step to implement this SVPWM method, which can be replicated for multilevel converters with any number of voltage levels. The presented method has been used and validated by various converters, including a three-level and a five-level neutral-point-clamped converter. The archive value of this paper is that it demonstrates a milestone of fast multilevel SVPWM based on coordinate transformation.

Design and Analysis of Closed Loop Control of Multilevel SVPWM Inverter Fed PMSM Drive

Permanent magnet synchronous machines have been universally used over induction machines in variable speed drives. For present trends and future developments, power electronics technology gives the extensive research of multilevel inverters that brings high safety voltages with low harmonic content in comparison with two-level inverter strategies. Multi level inverters implementation can be done by raising the number of power semi conductor controlled switching devices per phase to increase the number of inverter output voltage levels. By increasing the levels, power controlled switching devices and other components are increased, which makes the inverter complex and overpriced. From the above aspects, three-phase three-level inverter strategy is used for high performance and high voltage A.C drives. Multilevel inverter using a space vector pulse width modulation (SVPWM) strategy gives great advantages in high performance A.C drive applications. Various types of control strategies have been recommended for voltage source inverter fed A.C drives. In the proposed work, a PI controller is designed for the outer loop and non-linear controller using a state feedback linearization technique is designed for the inner loop. The closed loop control system for three-level inverter fed Permanent magnet synchronous motor drive employing SVPWM is extensively simulated using MATLAB.

Carrier-Based PWM Equivalent to Multilevel Multiphase Space Vector PWM Techniques

The space vector pulsewidth modulation (SVPWM) techniques enhance the performance of multilevel multiphase inverters. With multilevel (three-phase) inverters and with (two-level) multiphase inverters, it is widely accepted that the typical SVPWM strategies have an equivalent carrier-based pulsewidth modulation (CBPWM) counterpart, which produces identical results. However, the conclusions reached in the articles that show these cannot be applied, nor even extended, to SVPWM techniques with more than two levels and three phases. This article shows that the most widely accepted multilevel multiphase SVPWM techniques have a fully equivalent CBPWM counterpart, which consists of a phase disposition pulsewidth modulation with an appropriate zero-sequence injection scheme. Closed-form expressions to calculate the zero sequences are provided. The proposed modulation techniques are simulated and then implemented in a field-programmable gate array, showing that the equivalent CBPWM techniques produce identical results as the original SVPWM ones, but with a significant reduction of hardware requirements. The proposed methodology can be generalized to other multilevel multiphase SVPWM techniques.

Simplified multilevel space vector pulse-width modulation scheme based on two-level space vector pulse-width modulation

A novel simplified multilevel space vector pulse-width modulation (SVM) scheme is proposed based on the two-level SVM. The voltage vectors with same amplitude and phase angle are applied to the various power units of cascaded multilevel inverter (CMLI), and the refresh times of various vectors are delayed in order, thus the corresponding multilevel output voltage waveform is formatted. During every sampling period, only the on-times of main and auxiliary voltage vectors of one-stage unit are calculated based on a two-level SVM algorithm, so the computational complexity is independent on the unit-cascaded number. Then the algorithm is simplified, and the expandability is enhanced. The simulation and experimental results prove the validity and feasibility of the novel scheme.

A Space Vector PWM Scheme for Three level Inverters Based on Two-Level Space Vector PWM

Multilevel inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters. Among various modulation techniques for a multilevel inverter, the space vector pulse width modulation (SVPWM) is widely used. The complexity is due to the difficulty in determining the location of the reference vector, the calculation of ontimes, and the determination and selection of switching states. This paper proposes a general SVPWM algorithm for multilevel inverters based on standard two-level SVPWM. Since the proposed multilevel SVPWM method uses two-level modulation to calculate the on-times, the computation of on-times for an n-level inverter becomes easier. The proposed method uses a simple mapping to achieve the SVPWM for a multilevel inverter. A general n-level implementation is explained, and experimental results are given for two-level and three-level inverters.

Analytical Solutions of Multilevel Space-Vector PWM for Multiphase Voltage Source Inverters

This study systematically analyzes multilevel space-vector pulse width modulation for a multiphase voltage source inverter (VSI). The instantaneous output voltages of the VSI, which are called space vectors, can be classified according to the switching states of the VSI. By applying the eigenspace decomposition of the system matrix, the n-phase VSI control problem can be solved analytically. This analysis leads to a switching strategy that uses the fewest space vectors and minimum total conduction time. This yields a minimum switching number and efficient dc supply utilization. Further, the switching strategy of a multilevel multiphase VSI system can be solved based on the switching strategy of a two-level multiphase VSI. Simulations and experimental results confirm the effectiveness of the proposed algorithm.

A New Space-Vector PWM With Optimal Switching Selection for Multilevel Coupled Inductor Inverters

Multilevel space vector pulsewidth modulation (SVPWM) control is shown to be a very useful tool for coupled inductor inverters as six independent pulsewidth modulation (PWM) signals are required, and there is additional complexity of meeting the performance requirements for the coupled inductor while balancing the winding common-mode dc current and generating high-quality multilevel PWM output voltages. A new multilevel SVPWM technique with a five-segment switching sequence is described, where half-wave symmetrical PWM voltage waveforms are used to balance the inductor common-mode dc voltages and also to avoid all possible switching states with a high winding current ripple. The proposed SVPWM is shown to have better inverter performance, compared with traditional carrier-based and the original multilevel SVPWM schemes at low modulation depths. Inverter operation with the proposed SVPWM is validated through simulation and experimental results.

A Space Vector PWM Scheme for Multilevel Inverters Based on Two-Level Space Vector PWM

Multilevel inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters. Among various modulation techniques for a multilevel inverter, the space vector pulsewidth modulation (SVPWM) is widely used. However, the implementation of the SVPWM for a multilevel inverter is complicated. The complexity is due to the difficulty in determining the location of the reference vector, the calculation of on-times, and the determination and selection of switching states. This paper proposes a general SVPWM algorithm for multilevel inverters based on standard two-level SVPWM. Since the proposed multilevel SVPWM method uses two-level modulation to calculate the on-times, the computation of on-times for an n-level inverter becomes easier. The proposed method uses a simple mapping to achieve the SVPWM for a multilevel inverter. A general n-level implementation is explained, and experimental results are given for three-level and five-level inverters