space vector modulation

This paper has investigated the effect of space vector modulation techniques on leakage current for a two- level three-phase four-leg inverter used in PV system as the main objective. A modulation technique named RSPWM is proposed in which the CMV stays constant. Thus, the maximum leakage current has considerably decreased to below 300mA, as specified in the standard VDE-0126-1-1. In addition, some other characteristics of these modulation techniques have been evaluated which can lead to appropriate method selection proportionate to application purpose. As the results have shown, DPWM and NSPWM have the least switching loss. CSVPWM, DPWM and MSVPWM can operate in full linear modulation range. Also among all the methods, CSVPWM and MSVPWM have the lowest output voltage THD. Furthermore, the harmonic content of grid current is the least for RSPWM.

ABSTRACT: - In this study, direct torque control of induction motor is evaluated based on space vector modulation. DTC is a method to control machine with utilizing torque and flux of motor controlled. The torque and current ripple occurred in the conventional DTC. Reason of undesired torque and current ripple is low number of voltage vectors applied to the motor controlled by the conventional DTC technique. SVMDTC is a technique to reduce the ripple. SVM techniques have several advantages that are offering better DC bus utilization, lower torque ripple, lower total harmonic distortion in the AC motor current, lower switching loss, and easier to implement in the digital systems. Simulation results from the classical and improved DTC are presented and compared. Result shows that the torque, flux linkage and stator current ripple are decreased with the improved DTC.

" I hereby declare that I have read through this report entitle " Space Vector Modulation for Five-phase Induction Speed Drive Control" and found that it has comply the partial fulfilment for awarding the degree of Bachelor of Electrical Engineering (Power Electronic and Drive) "

Takahashi and Noguchi. Direct torque control (DTC)drives are finding great interest, since ABB recently introduced the first industrial direct-torque- controlled induction motordrive in the mid-1980’s, which can work even at zero speed. This is a very significant industrial contribution.Conventional direct torque controlled induction motors are utilized hysteresis controller to compensate the flux and torqueerrors. Due to the use of flu x and torque hysteresis controller, conventional DTC suffers fro m high torque ripples and alsoswitching frequency is variable. To overco me the disadvantages of conventional DTC, several techniques have beendeveloped. One of them is the direct torque control using space vector modulation (DTC-SVM ). Space vector modulation isan algorithm wh ich is used to calculate the required voltage space vector to compensate the flu x and torque ripples. SVMtechnique is based on the switching between two adjacent boundaries of a zero vector and active vectors. SVM techniqueshave several advantages such as, lower torque ripple, lower switching losses. Also lower Total Harmonic Distortion (THD)in the current, and easier to implement in the dig ital systems.In this paper, SVM-DTC technique with PIcontroller for induction machine drives is developed.Furthermore, a robust full-order speed adaptivestator flu x observer is designed for a speed sensorless DTC-SVM system and a speed-adaptive law isgiven. The observer gain matrix, which is obtainedby solving linear matrix inequality, can improve therobustness of the adaptive observer gain in [7]. Thestability of the speed adaptive stator flu x observer isalso guaranteed by the gain matrix in very lowspeed. The proposed control algorith ms are verifiedby extensive simulation results.

Copyright to IJAREEIE DOI:10.15662/IJAREEIE.2016.0507064 6481 current. The back propagation method is used for the training process of the ANN. By using the ANN outputs the Space Vector Modulation (SVM) technique improves the control pulses for the multilevel inverter. Then the proposed intelligence method is implemented in the MATLAB/simulink platform and the effectiveness is evaluated by comparing with the various case studies i.e., Case 1: Here, the torque controller has been continuing with the proposed ANN stage 1 controller but the flux controller is dropped the ANN stage 2 controllers. Case 2: during which the torque controller has been dropped at the ANN stage 1 controller but the flux controller is allowed with the ANN stage 2 controllers and PI Controller : In this section described about the 5 level inverter DTC scheme with normal proportional integral (PI) controller results.

Voltage source inverters (VSI) have been widely used in the production of three-phase non-sinusoidal quasi-square wave voltages and vector analysis has also been applied to the analysis of these inverters [1, 2]. The production of sinusoidal waveforms from these inverters has been accomplished with the familiar space vector modulation approach [3 – 5] which was applied to a three-phase unity power factor ac to dc converter by Busse and Holtz [6]. The space vector modulation (SVM) technique modulates the adjacent stationary switching space vectors of a quasi-square wave drive to produce a variable voltage and variable frequency sinusoidal output, with the rotating resultant voltage space vector displaying a circular trajectory. However, the trajectory of the resultant voltage space vector produced by a quasi-square inverter has been reported to be hexagonal in nature [2, 7] with little emphasis being placed onits origin. In addition, the choice of using line or phase quantities in the production of the resultant switching space vectors of a quasi-square wave drive and the magnetic axes with which they are referred, have not been elaborated on in the literature.

Speed regulation of three-phase induction motor was difficult under variable load torque conditions. In this paper, v/f control technique for speed control of induction motor using space vector modulation technique is proposed. Mathematical modeling of induction motor was also described. A typical space vector modulation technique was designed for two-level voltage source converter. Three-phase diode rectifier is used across power supply. For regulation DC bus voltage a DC breaking chopper under abnormal load conditions. Simulation analysis is carried out for proposed system to describe performance characteristics. The proposed concept is fully validated and results are described in section V.

Full Length Research Article HIGH PERFORMANCE SPEED OF THE INDUCTION MOTOR DRIVES BY THE PREDICTIVE CONTROL USING SPACE VECTOR MODULATION *Lakhdar Djaghdali, Belkacem Sebti and Farid Nac[r]

In the given traditional SVPWM algorithm, the evaluation of sectors is done with the complex operation of coordinate rotation, trigonometric & inverse trigonometric function and so on. Due to the complexity to realize this algorithm, a simplified SVPWM algorithm is introduced to build the model of DTC drive system [13]. A hybrid control direct torque control (DTC) scheme is given for medium voltage induction motor drive. For the closed loop implementation of their commended scheme, an application of carrier-based space vector modulation (CBSVM) controlled five-level diode clamped multi-level inverter (DCMLI) is presented [14].

A simple scheme based on space vector modulation for an eight-switch three-phase NPC converter is presented to save the calculation time, to obtain the time duration of power switches, and to control the line currents with unity input power factor. The circuit configuration is simple compared with the conventional twelve-switch three-phase NPC converter. Only eight power switches and four clamping diodes are used in the converter. In the proposed converter, the dc bus voltage is greater than two times of line voltage (v dc > 2v line ). The

In traditional DTC, one of the 6 magnitude vectors of 3 3 combinations is controlled flux and torque inside the breaking points of hysteresis limits. Likewise in traditional DTC the ON/OFF of SRM converter switches are controlled by the error in torque and flux however extensive and little mistakes are not recognized. The exchanging vectors had picked same for expansive and little blunders. Keeping in mind the end goal to defeat this issue, SVM-DTC techniques were presented. Space vector modulation (SVM) modulator is joined with direct torque control for prompting engine drives as appeared in [9]-[11] to give a consistent inverter switch- ing frequency. Noticing that the torque ripple and acoustic noise issue for this SVM-based DTC methodology are essentially enhanced for invoking zero inverter switching state inside each switching time of inverter con- trol.

ABSTRACT: With increasing research and advancement in solid-state power electronic devices and microprocessors, various inverter control techniques employing pulse-width-modulation (PWM) are becoming popular esp. in AC motor drive applications. The most commonly used techniques are Sine PWM and Space vector modulation (SVPWM). SVPWM is considered to be superior to the SPWM because of better DC bus utilization. This paper focuses on step by step development of MATLAB/SIMULINK model of SVPWM.Firstly model of a three-phase VSI is discussedbased on space vector representation. Nextsimulation model of SVPWM is obtained using MATLAB/SIMULINK. Finally the simulation results of SVM are compared with SPWM.

In recent years and with its economic and environmental benefits, wind energy has become more and more a source of energy for many countries, i n addition, and because of its advantages, the dual feed induction generator (DFIG) is currently the generator of choice for driven wind turbines [1-8]. The vector control (VC) using conventional proportional-integral (PI) controllers allows decoupled control of the active and reactive powers typically applied for their simplicity [9-10]. However, the VC structure strongly count on the parameters of the machine and require exact knowleduses of the system model, therefore can not ensure the robustness of the system in the face of parameter variations and model uncertainties. Different strategies have been presented in the literature to remedy the aforementioned difficulties. Direct torque control (DTC) or direct power control (DPC) has been introduced in [11-12]. The application of DPC on the DFIG had many advantages over the classical VC method: no coordinate transformations, no current loops, less dependence on parameters. From its basic version the classical direct power control causes fluctuations in the currents, the reactive, active powers and the variable switching frequency because of the use of hysteresis regulators. Several approaches are suggested on the development of DPC techniques operating at a constant switching frequency. using space vector modulation [13-16]. its precaution is elimination of the hysteresis regulators and the switching table. The reduction of the power pulsation and the quality of the power has been achieved. These controllers are not robust to uncertain parameters.

Our paper is organized in the following way. In section 2, we find the problem of the formulation of optimal hybrid control, the methodology, the materials and some basic aspects. Session 3 is dedicated to showing the results and discussing the evaluation obtained from the optimal hybrid control problem used for the development of Space Vector Modulation (SVM). In section 4, we present the conclusions obtained from the computational approach used based on gradient for the initial problem of Space Vector Modulation (SVM) [28], [29], [30].

Permanent magnet synchronous motor drives (PMSM) offers many advantages over the induction motor, such as overall efficiency, effective use of reluctance torque, smaller losses and compact motor size. In recent years many studies have been developed to find out different solutions for the PMSM drive control having the features of quick and precise torque response, and the field oriented control has been recognized as viable and robust solution to achieve these requirements. In this paper total harmonic distortion studied using space vector modulation technique on permanent magnet synchronous machine.

Theoretically, the zero-vectors (000 and 111) can be split apart and arranged appropriately in one switching cycle with other SVM schemes so that the effect of zero-vector overlap would be minimized or eliminated in a switching cycle. Uncertainties, however, exist in sys- tem transients and sector transition, where transition chattering is likely to occur because of the current ripple. Once the overlap is created, the zero-sequence will exist in at least one switching cycle before it can be corrected. Because the current loop operates as a feed back loop based on the existing current to perform the following actions, it can not be so fast as to eliminate the switching frequency current. And the overlap time between zero vectors (000 and 111) is decided to vector 000. Therefore, discontinuous space-vector modulation without using zero vector(000) to eliminate the zero vectors overlap time is an effective method for interleaved parallel sys- tem. Figure 10 shows the principle of this modulation method, in a switching cycle, zero vector(000) using the two of the other switching cycle modulation vector and the inverse vector to synthesized. In the first sector, for example, the modulation vector of the inverter 1 is 111,110,100,000, and the effective time of each vector is

Abstract: This paper proposes a new 3-phase multilevel inverter that is able to generate 7 levels in line-to-line voltage with only 11 switches. The inverter is formed from the 6-switch conventional full-bridge topology with the addition of 5 bidirectional switches in which 2 of them are shared among the three phases. By doing so, the number of power switches can be minimized, thus reducing the complexity in generating and controlling PWM signals. A novel voltage control scheme based on space vector modulation is developed by introducing a virtual vector in every sector of the vector hexagon. This is to overcome the difficulty in decomposing the reference vector in some parts of each sector. To evaluate the performance of the inverter and the effectiveness of the modulation technique in real time, a hardware prototype is constructed and the algorithm is implemented on a TMS320F2812 DSP. From the experimental results the optimum operating range of the inverter is determined to achieve the best output voltage possible with respect to quality and amplitude.

This paper proposes a simplified space vector modulation (SVM) scheme for multilevel converters. Compared with earlier SVM methods, the proposed scheme simplifies the detection of the nearest three vectors and the generation of switching sequences, and therefore is computationally more efficient. Particularly, for the first time, the proposed scheme achieves the same easy implementation as phase- voltage modulation techniques. Another superior characteristic of the proposed scheme over earlier methods is its potential for multiphase multilevel applications.

3. ProposedDiscreteSpaceVectorModulation The classical vector control algorithm gives more harmonic distortion and also more complex for real time implementation. To reduce the complexity and harmonic distortion the discrete space vector modulation (DSVM) technique is proposed for the proposed vector control. The proposed DSVM [8]-[9] uses a two-level hysteresis controller for d-axis current loop (DHC) similar to that of classical DTC algorithm and five-level hysteresis comparator for q-axis current loop. The DSVM technique uses a standard voltage source inverter and synthesizes a higher number of voltage vectors than those used in classical DTC algorithm. In the DSVM technique, each sampling time interval is divided into ‘k’ equal time intervals and any one of the voltage vector is applied in each sub- interval. The number of voltage vectors that produced is directly proportional to ‘k’. if the number of sub- intervals is more, then the complexity involved in constructing the switching table is also more. A good compromise between the errors compensation and the complexity of the switching tables is achieved by choosing k=3 [8]. By using the DSVM algorithm, with k=3,atotalof36synthesizednon-zerovoltagevectors

3. K. Mounika, B. Kiran Babu introduced a topology in which they applied PWM techniques like Sinusoidal pulse width modulation (SPWM) and Space Vector Pulse width Modulation (SVPWM) to inverter and studied its performance. In Sinusoidal Pulse width modulation (SPWM) the gating signals is generated by comparing a sinusoidal reference signal with a triangular carrier wave. In Space vector Modulation (SVPWM) a rotating phased which is obtained by adding all the three voltages is considered. Modulation is accomplished by switching state of an inverter. Thus by comparing these two techniques the performance of our inverter is studied.