Vector Pulse Width Modulation Strategy Research Articles

Research on Two Improved High–Voltage–Transfer–Ratio Space–Vector Pulse–Width–Modulation Strategies Applied to Five–Phase Inverter

Research on Two Improved High–Voltage–Transfer–Ratio Space–Vector Pulse–Width–Modulation Strategies Applied to Five–Phase Inverter

Performance Analysis of a Dual-Inverter-Fed Open-End Winding Induction Machine under Asymmetrical Control: Theoretical Approach and Experimental Validation

Currently, power trains based on an Open-End Winding Induction Machine fed by a Dual Inverter (DI-OEWIM) are attracting a great deal of interest in various modern industrial applications. However, applying symmetrical control to this system (DI-OEWIM), which is symmetrical in nature, will lead to malfunction. Therefore, the objective of this paper is to explore the influence of asymmetric control on the performance of this system. The principle of this study is to create an asymmetrical control by integrating a phase-shift angle in the Space Vector Pulse Width Modulation (SVPWM) strategy. We then evaluate the impact of these angles on various performances, such as the Total Harmonic Distortion (THD), power losses, Common Mode Voltage (CMV), Zero-Sequence Voltage (ZSV), rotation speed and torque ripple of this system. This study was carried out in the Matlab/Simulink environment and was validated experimentally using the dSPACE 1104 board. The results show that the different angles have significant effects on the overall performance of this system.

A Study on Various Causes of Low Frequency Components in Common Mode Voltage of a Space Vector Pulse Width Modulated Three– Phase Quasi–Z–Source H–Bridge Inverter Fed from a Three–Phase Diode Bridge Rectifier

Abstract The presence of low frequency components in the common mode voltage can cause harmful electromagnetic interference. A critical study on various causes of low frequency components in the common mode voltage of a space vector pulse width modulated Quasi–Z– source three–phase H–bridge voltage source inverter fed from a three–phase diode bridge rectifier is presented in this paper. The Quasi–Z–source network is utilized in boosting the rectified dc voltage which increases the overall voltage gain. The study considers the effect of boosting on the low frequency components. The input three-phase diode bridge rectifier has its influence in modulating the instantaneous common mode voltage and contributes low frequency components. The unbalanced three-phase supply can contribute additionally ac supply frequency component in the common mode voltage. The major contribution of this paper is the analytical, simulated and experiment-based study on various causes of the low frequency common mode voltages due to the combined action of the input non-ideal three phase grid, the front-end diode bridge rectifier as well as the load-end Z-source H-bridge three-phase inverter feeding a three-phase inductive load, while operated through a space vector pulse width modulation strategy.

A Simplified Space Vector Pulse Width Modulation Strategy for NPC Six-Phase Three-Level Inverter Considering Neutral-Point Potential Balancing

A Simplified Space Vector Pulse Width Modulation Strategy for NPC Six-Phase Three-Level Inverter Considering Neutral-Point Potential Balancing

The voltage feedforward based pulse width modulation strategy under the fluctuated dc‐link voltage for a unidirectional five‐level ac motor drive system with open‐end winding connection

SummaryIn a unidirectional five‐level ac motor drive system with open‐end winding connection, because of the variation of operating frequency of ac motor, the instantaneous power fluctuation of rectifier stage and inverter stage will generate larger voltage ripple on each phase dc‐link capacitors, and further lead to a large amount of current harmonics in output currents of inverter. To cope with this problem, an improved space vector pulse width modulation (SVPWM) strategy based on dc‐link voltage feedforward is proposed. In this paper, the effects of zero sequence current harmonics caused by dc‐link voltage ripple on ac motor are firstly analyzed, including the stator winding flux linkage equation, voltage equation, and electromagnetic torque. Then, the generating mechanism of dc‐link voltage ripple and the current harmonics are discussed in detail in terms of instantaneous power fluctuation of each single‐phase converter. Based on this, an improved SVPWM strategy by modifying the modulation signal is proposed to suppress the generation of current harmonics. Finally, a 2.2 kW prototype experimental results are given, which verify the feasibility and advancement of the proposed modulation strategy.

Experimental analysis of advanced control technique for a five‐phase direct matrix converter based on space vector PWM

AbstractThe multiphase matrix converter outperforms the conventional three‐phase system with higher fault tolerance capability and higher power control competency. This paper discusses the direct control based on different possible switching combinations of a three‐phase to five‐phase matrix converter (MC). The proposed control topology significantly reduces the switching commutations in a switching cycle when compared with its counterpart. The control is based on the modified space vector pulse width modulation (SVPWM) strategy. The proposed space vector scheme intelligently selects the voltage vectors to get the desired output characteristics with the least possible switching transitions in a switching cycle. Three possible cases exist in controlling space vectors based on their magnitude, the number of active switching vectors, and their commutations. The results for three different cases of SVPWM have been presented and compared. The total harmonic distortion (THD) obtained in the output is lower in case 2; however, it suffers from a higher common‐mode voltage (CMV). The scheme has been successfully implemented and verified in hardware.

Multiaverage Random Switching Frequency Space Vector Pulsewidth Modulation Strategy for High-Order Harmonics Dispersion

A multi-average random switching frequency space vector pulse width modulation (MARSF-SVPWM) strategy is proposed in this paper, in order to further disperse the high-order harmonics concentrated at the switching frequency and its integer multiplies in the output voltage of the inverter. The proposed strategy divides the fundamental period equally, with different stages corresponding to different average switching frequencies and spread-spectrum ranges, in contrast with the conventional random switching frequency space vector pulse width modulation (RSF-SVPWM), under the premise of maintaining the same overall average switching frequency and spread-spectrum range. The simulation and experimental results demonstrate that, even in the case of a narrow spread-spectrum range, the proposed MARSF-SVPWM strategy can obtain a better effect of high-order harmonic dispersion.

Experimental Validation of Different Control Techniques Applied to a Five-Phase Open-End Winding Induction Motor

Open-end winding five-phase induction motor (OeW-5PIM) configuration is used in industrial applications, where minimization in the total harmonic currents and high reliability are needed. The majority of the literature on OeW-5PIM topology discusses field-oriented control and direct torque control in addition to other robust control techniques such as the backstepping approach. This paper focuses on the mathematical and experimental approaches of backstepping control (BSC) and rotor-flux-oriented control (RFOC) for an OeW-5PIM topology. The space vector pulse width modulation (SVPWM) strategy is associated with the suggested control techniques to improve the dynamic performance (i.e., reducing ripple, fixed switching frequency, etc.) of the studied motor. Furthermore, the RFOC-SVPWM and BSC-SVPWM are comprehensively compared using experimental implementation under various situations such as load torque, open-phase fault, and high/low-speed operation.

Space vector pulse width modulation strategy for modular multilevel converters in power system

AbstractAs a superior modulation strategy, space vector pulse width modulation (SVPWM) provides redundant voltage vectors and adjustable action time, which can achieve multi‐objective control of modular multilevel converter (MMC). An SVPWM strategy suitable for MMC is proposed. The strategy is divided into three stages. In the first stage, the appropriate voltage vector, the action time and the basic sub‐module (SM) input number are quickly calculated to ensure the output quality by equating MMC as a 2‐level inverter. In the second stage, a finite set of the circulating current suppression is established on the basis of the basic SM input number. The optimal SM input number is selected through rolling optimisation. In the last stage, according to the SM voltage sorting and the optimal SM input number, the optimal switching state is determined to realise the SM voltage balance control. The proposed control strategy simplifies the design of the control system, reduces the computational burden and can be easily extended to MMC with any SM number. The simulation and experimental results show that the proposed SVPWM strategy can reduce the circulating current and balance the SM capacitor voltage while ensuring the output quality.

An Enhanced Space Vector PWM Strategies for Three Phase Asymmetric Multilevel Inverter

This work presents the two space vector pulse width modulation (SVPWM-I and SVPWM-II) strategies for eleven-level (11L) asymmetric cascaded H-bridge (CHB) multilevel inverter (MLI). Depending on the isolated structure and nonappearance of capacitor voltage balancing issues, the CHB MLI structure is favoured. These days, the SVPWM control method is accomplished superior consideration among the diverse PWM methods. In common, the SVPWM strategy is realized based on deteriorating higher-level hexagons into a lower level hexagon (2-level). Compared to the classical SVPWM strategy, the proposed SVPWM-I strategy decreases the memory and mathematical burden necessity included within the demonstration of eleven-level SVPWM devoid of losing the inverter output voltage (AC) contour by diminution the number of two-level hexagons. Also, the SVPWM-II strategy is presented, which incredibly diminishes the mathematical endeavours. The presented two SVPWM methods performed on an eleven-level asymmetric CHB multilevel inverter (MLI) by utilizing SIMULINK/MATLAB program tool and are compared with conventional sinusoidal PWM and Third harmonic injection (THI) PWM methods to confirm the proposed SVPWM methods. The proposed SVPWM methods give higher AC RMS voltage and lower harmonic distortion when compared to SPWM and THIPWM methods. To validate the presented two SVPWM control schemes, hardware results are taken on asymmetric eleven-level CHB MLI.

A hysteresis current control PWM for PV tied Z-source NPC-MLI fed induction motor with neutral point balancing

Photo-voltaic (PV) tied Z-source Neutral-point clamped NPC-MLI (Z-NPC-MLI) is used in solar grid connected applications due to its improved performance related to conservative inverters due to its single stage power conversion. Though the Z source inverters adaptation is accepted in grid connected technology, the need for appropriate controller to meet out the grid/standalone requirements is becoming necessary. The space vector pulse width modulation (SVPWM) strategy is a prominent modulation technique for Z-source NPC-MLIs due to their appropriate voltage vector selection opportunity. The current controller (CC) based SVPWM is not attempted, which is the most essential consideration for the grid connected inverter to provide a low harmonic distortion, high quality current. With all this aim, the paper presents a PV tied Z-NPC-MLI grid connected system with a unique hysteresis current control SVPWM (HSVM) strategy with neutral point (NP) balancing control. The simulation results are confirmed the feasibility and reliability of the proposed CC for the PV tie grid connected Z- Source MLI.

EMI-Regulated SiC-Based Motor Drives With Markov Chain Pseudo-Random Frequency Space Vector Pulse Width Modulation Strategy

Compared with traditional silicon-based (Si) power devices, wide-bandgap (WBG) power devices have broader application prospects in AC motor drive due to their high-temperature reliability, low conduction, and switching losses. However, a fast switching process and high switching frequency will cause more serious conducted electromagnetic interference (EMI) emission. To solve the problem, this paper proposed a pseudo-random frequency space vector pulse width modulation (PRF-SVPWM) strategy based on a carrier with a pseudo-random frequency. There are two sawtooth waves with the same frequency but opposite phases as alternatives. The proposed method randomly selects only one sawtooth wave during a complete control period. After random combination, the generated carrier is no longer a regular sawtooth wave. This new carrier contains 4 different modes including 2 sawtooth (positive and negative) and 2 triangular waves (positive and negative). A 2-state Markov chain is introduced to produce a PRF control signal which is regarded as the law of choice. In this way, the equivalent switching frequency keeps constant but the real-time switching frequency will randomly vary within the determined range. EMI emission level can be significantly reduced. The effectiveness of the proposed PRF-SVPWM is verified by several sets of experiment results.

Zero-sequence Current Suppressing Strategy for Dual Three-phase Permanent Magnet Synchronous Machines Connected with Single Neutral Point

Dual three-phase permanent-magnet synchronous machines (DTP-PMSM) connected with a single neutral point provide a loop for zero-sequence current (ZSC). This paper proposes a novel space vector pulse width modulation (SVPWM) strategy to suppress the ZSC. Five vectors are selected as basic voltage vectors in one switching period. The fundamental and harmonic planes and the zero-sequence plane are taken into consideration to synthesis the reference voltage vector. To suppress the ZSC, a non-zero zero-sequence voltage (ZSV) is generated to compensate the third harmonic back-EMF. Rather than triangular carrier modulation, the sawtooth carrier modulation strategy is used to generate asymmetric PWM signals. The modulation range is investigated to explore the variation of modulation range caused by considering the zero-sequence plane. With the proposed method, the ZSC can be considerably reduced. The simulated and experimental results are presented to validate the effectiveness of the proposed modulation strategy.

An Adaptive Control of Electric Vehicle Based on Nine Switches Inverter Fed Two Induction Motors

This paper deals with an adaptive control of two driving-wheels electric vehicle. Indeed, an Indirect Field Oriented Control of two induction motors fed simultaneously by Nine Switches Inverter has been included. Hence, to ensure an independent control of the two induction motors, a specified Space Vector Pulse Width Modulation strategy for Nine Switches Inverter is developed. For this, a switching table and a switch-over bloc are proposed. The effectiveness of the proposed control strategy is evaluated and validated by simulations and experimental tests. In this context, the developed system can be used as a promising solution for an independent control of two driving wheels of electric vehicle using a software differential.

Comparison of Interior Mounted Permanent Magnet Synchronous Motor Drives with Sinusoidal, Third Harmonic Injection, and Space Vector Pulse Width Modulation Strategies with particular attention to Current Distortions and Torque Ripples

Comparison of Interior Mounted Permanent Magnet Synchronous Motor Drives with Sinusoidal, Third Harmonic Injection, and Space Vector Pulse Width Modulation Strategies with particular attention to Current Distortions and Torque Ripples

DC Current Harmonics Reduction in Multi-Inverter Topology

This letter presents a Space Vector Pulse Width Modulation (SVPWM) strategy for reducing the DC-link current harmonics in a multi– Voltage Source Inverter (VSI) topology with common DC-link bus. The DC current harmonic reduction is achieved by phase-shifting the PWM pattern of individual VSIs, with the inverters sharing the system total power. Simulation and experimental results are shown to validate the proposal.

A seven-level cascaded multilevel inverter based on simplified SVPWM method

The multilevel converters are extremely widespread alternatives within megawatt power level as well as medium voltage level applications due to their excellent execution than the typical two-level converters. The widely applied control strategies aimed at inverters are Sine Pulse Width Modulation (SPWM) and Space Vector Pulse Width Modulation (SVPWM) strategies. In between these two PWM methods, the SVPWM strategy has excellent execution as compared to the SPWM strategy as a result of improved DC link voltage use as well as a decrease in Total Harmonic Distortion (THD) in output voltages. A traditional SVPWM strategy owns numerous weaknesses like computational complications in terms of identification of the reference voltage vector position, to identify sector, triangle and also it requires large memory for storing look up tables used for switching vectors. This paper presents, an innovative modified SVPWM strategy aimed at Cascaded H-Bridge Multilevel Inverter (CHBMLI). The novel modified SVPWM strategy has overwhelm the downsides of traditional SVPWM strategy. A seven-level CHBMLI is used for the implementation of this simplified SVPWM method to assess performance and as well to made comparison with the SPWM strategy. A MATLAB software is used for the simulation.

A Voltage Spike Suppression Strategy Based on De-Re-Coupling Idea for the Three-Phase High-Frequency Isolated Matrix-Type Inverter

In order to solve the problem of high voltage spikes on the secondary side of the high-frequency transformer when the three-phase high-frequency isolated matrix inverter (HFIMI) operates under the conventional modulation strategies, a new modulation strategy is proposed without introducing an auxiliary circuit. In the proposed scheme, the H-bridge inverter adopts phase-shift control. The matrix converter (MC) adopts the voltage-type de- and recoupling idea, and the decoupled positive and negative group inverters are, respectively, applied with a modified Space vector pulse width modulation (SVPWM) strategy to operate synchronously with the H-bridge inverter. When the H-bridge inverter is in dead-zone mode, the switching tubes of MC are all turned <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> to provide continuous flow paths for leakage inductance and output filter inductance current and suppress high voltage spikes. The operating mode of the three-phase HFIMI under the proposed modulation strategy is analyzed in detail, the realization conditions for soft switching are designed, and the soft-switching ranges are also discussed. The feasibility and validity of the voltage spike suppression strategy are verified by building a 3-kW principle prototype. The experimental results show that the voltage spikes are effectively suppressed, all switches achieve zero-voltage soft-switching, and the peak efficiency of the three-phase HFIMI can reach 95.2%.

Space vector pulse width amplitude modulation strategy for three-level direct matrix converter

The total harmonic distortion and switching stress of a three-level direct matrix converter (TLDMC) is greatly reduced in comparison with those of a conventional matrix converter (MC). Meanwhile, the TLDMC leads to major advantages in comparison with existing multi-level AC–DC–AC converter topologies in terms of reduced switch counts and lowered switching power loss. In this paper, a space vector pulse width amplitude modulation (SVPWAM) strategy for the TLDMC is proposed, which can reduce the number of switching actions and improve the voltage utilization by eliminating the zero vector of each sector. An indirect modulation model of a TLDMC is discussed according to the topology of TLDMC in this paper. For the space vector modulation of the TLDMC, the space vector pulse width modulation (SVPWM) with a zero-vector of the fictitious rectifier stage is improved to form the SVPWAM. In addition, the virtual space vector pulse width modulation (VSVPWM) strategy is used for the fictitious inverter stage. Finally, simulation and experimental results verify the correctness of the proposed method.

Backstepping Control of High-Frequency Link Matrix Rectifier for Battery Chargers

High-frequency link matrix rectifier (HFLMR) is getting much interest in electric vehicle charger applications due to its high efficiency and compact volume. However, the inputs and outputs of HFLMR are highly coupled resulting in reduced system dynamic performance and robustness. This article proposes a dual closed-loop backstepping control (DCL-BSC) strategy to solve these problems, which consists of a dc output current outer-loop controller and a grid current inner-loop controller. First, the nonlinear mathematical model of HFLMR is established, and the six-segment space vector pulse width modulation scheme is used as the modulation method. Then, the DCL-BSC scheme is designed in detail based on the Lyapunov stability theory. And a compensation method based on the phase-shift angle is developed to realize the unity power factor. Compared with the conventional dual closed-loop PI control method, the proposed method has a better steady-state and dynamic performance, and robustness against system disturbances. Simulation and experimental results are used to verify the effectiveness of the proposed control scheme.