Ac Ac Converter Matlab Simulink

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AC to DC Three Level Pulse Width Modulation Converter by Using

Matlab Simulink

Abdullahi Mohamed Samatar, Universiti Tun Hussein Onn, Malaysia

1. Introduction

AC-to-DC energy converters occur generally utilized within cables and data-midpointindustriousness. These types of converters change over the use AC energy to steady DC output appropriate for the output loads. The generation of the multiple voltage-level PWM voltage is based on the multilevel voltage source converter (VSC) power stages. The most frequently used VSC, AC to DC converters and power converters (A. Baluguri and P. B. Nanda, 2014). VSC-HVDC system is a new generation of HVDC technology based on pulse width modulation and voltage source converter (VSC), the modern high-power power electronic technology applied in the power system. The introduction of pulse width modulated voltage source converter technology into high voltage DC (HVDC) transmission system has booster their practicality in many appliances in terms of cost expense and performances.

Figure: System Model & Simulation Flow for Ac Ac Converter Matlab Simulink

To overcome drawbacks of Diode Bridge rectified, pulse width modulation (PWM) converters are proposed. The current PWM techniques are discussed in (B. Lin, 2000). Although there are different PWM techniques are accessible for Alternating current (AC) and direct current (DC) converters however the hysteresis current control is exceptionally prevalent technique due to crucial peak current limit, simple to implement and unresponsive to parameter difference.

Figure: System Model & Simulation Flow for Ac Ac Converter Matlab Simulink

2. Related Work

Traditionally, AC to DC converters, which are also known called as rectifiers, are developed using diodes and thyristors to provide controlled and uncontrolled unidirectional and bidirectional DC power. They have the issues of poor power quality in terms of injected current harmonics, DC output voltage distortion and poor power factor at input AC mains and gradually differing ripple DC output at load end, low efficiency, and extensive size of AC and DC filter. In perspective of their expanded applications, another type of rectifiers has been developed new solid-state self-commutating devices, for example, MOSFETs, insulated gate bipolar transistors (IGBTs), gate-turn off thyristors and (GTOs). Such converters are generally classified as switch mode rectifiers (SMRs), (PWM) rectifiers, multilevel rectifiers or multi-pulse rectifiers. Because of the strict requirement of power quality at the input AC mains, several standards been developed and enforced on the purchasers. Because of the severity of power quality issues some other options such as passive filter, active filter and hybrid filter alongside conventional rectifiers have been extensively developed, particularly in large rating and already existing installations. However, these filters are quite costly, bulky, and have reasonable losses, which reduce overall efficiency of the complete system, under such circumstance; it is considered better option to use such converters as an inherent part of the system. Under such circumstance, it is considered better option to use such converters as an inherent part of the system of AC to DC conversion, which provides reduced size, high efficiency, and well controlled and regulated DC to provide comfortable and flexible operation of the system (12).

Figure: System Model & Simulation Flow for Ac Ac Converter Matlab Simulink

Abstract

Another AC-DC single stage three level thunderous converter for high voltage DC distribution system of data centres applications is presented in this assignment. This converter changes general data voltage assortment (90-265Vrms) to 380V DC with high power factor. The expected topology retains a bridgeless booster converter and a half-bridge three level loud converter. Consequently, Voltage stresses on the switches are minimized to half of the DC bus voltage. Conduction losses and switches losses are reduced by eliminating with the rectifier bridge diode and achieving ZVS process over a wide load extend.

The converter is worked in DCM mode with the mixture control of PWM and frequency. Also, the symmetrical operation keeps the voltage adjusts of two DC bus capacitor without the associate circuit. In the paper, the operation and stable state of the proposed converter is illuminated and separated in detail.

Keywords: Pulse Width Modulation (PWM), Neutral Point Clamped (NPC) Three-Level AC-DC converter, Voltage Sourced Converter(VSC), Improved Power Quality Converters (IPQC).

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The close loop current control block diagram of 3 stage three-level of neutral point clamped (NPC) AC to-DC converter is presented in Fig. 1. This NPC AC-DC converter converted and description and modelling are well known (M. Milanovie, B. Sedmak, F. Mihalie, and A. Hren, 2000 ). The reference current of each phase is subtracted from the actual current of respective phase and tracking error is handled through signal decoder and lock out circuit. This is inward current control loop as shown in Figure 1.

Figure 1: Close loop current control block diagram The flowchart of the project as shown in Figure 2.

Figure 2: Flowchart Of The Project

External loop DC link voltage control and the inward current control loop block diagram is shows in Fig. 3 and this control technique offers rise to variable and unpredictable switching frequency (N. E. D. Mohan and C. Zach, 2012). To obtain constant switching frequency variable, a forced switching technique is assumed and the detailed switching control is clearly mentioned in Figure 3.

Figure 3: Dc Link Voltage Control

To get suitable condition for stability of the AC-DC converter system in terms of given system parameters a state space modelling is carried out (R. K. Behera, 2016). The phase plane study based on has been completed for the triangular carrier frequency of 1 to 5 kHz. It ensures that the AC-DC converter is steady for all the compelling carrier frequencies.

The regularly topology about AC-to-DC rectifier is gathered of a front-end AC-to-DC booster converter and increasingly a full-bridge DC-to DC converter. In order to accomplish understand a high-power factor which is essential in harmonics standard the front of booster converter forms the current input to a sinusoid waveform.

3.1 Operation Of The Proposed Converter

Figure. 3 shows that the circuit topology, the AC input Vin is among the focal point of the switches (S1, S2, S2 and S4) and double input rectifier diodes D1 and D2. Therefore, the double current input affecting inductor Lin1 and Lin2 are conduct for the duration of the negative and positive cycle of the Vin. Cb1 and Cb2 are the DC-bus capacitors which give out the DC bus voltage similarly (A. M, 2016). Dc1 and Dc2 fastened the shift voltages in the direction of part of the DC bus voltage as shown in Figure 4.

Figure 4: suggested 3-level booming single-stage DC-DC converter A sequence parallel resonant tank which is contained of Cs, Ls and Cp are used on control the output voltage by freuency control, in (C. Wang, S. Pan, and P. Jain, 2016). Lf and Cf is the output LC filter. However, the input inductor Lin1 and Lin2 are proposed to work in DCM mode like the input current may be sinusoidal waveform naturally.

Consequently, the ripple voltage of DC bus voltage is actually high with low-slung value of D. however, low quality of Di is only essential at the time DC bus voltage remains high and therefore, the ripple stay not that important when compared to a high DC bus voltage. Thus, the DC bus for voltage ripple may be good structured with an appropriate configurated DC bus capacitors 'evaluate.

The simulation AC to DC converter of three level PWM converter is composed and verified by the input range of AC root mean square (RMS) (Y. Son, S. Chee, and Y. Lee, 2016) .In evaluation with the converter exhibited, the converter appeared in this project has an interleaved structure, needs two less diodes in the DC, has a yield current which is persistent for all load ranges, has a DC bus voltage which is smaller than 450V for all load conditions, and has an extremely improved information current

3.2 Converter Design And Analysis

The study and the design of the suggested interleaved converter are nearly identical to that showed (Y. Xue, L. Chang, S. B. Kjær, J. Bordonau, and T. Shimizu, 2004). With respect to analysis, steady-state operating points are acknowledged using a matlab simulink. The only one difference among the analysis of the proposed converter and the one is the analysis and design of the input inductors. However, in the proposed interleaved converter, there are two sets of inductors (L1 andL2) at the input side, with every set conducting half the current (P. I. High-voltage and V. Michal, 2016). The analysis requires to consider the current in both sets instead of just one.

Deployment In Out-Of-Position Situations

D. Bendjaballah1, A. Bouchoucha1, M. L. Sahli1,2* and J-C. Gelin2

Abstract

Side-impact collisions represent the second greatest cause of fatality in motor vehicle accidents. Side-impact airbags have been installed in recent model year vehicle due to its effectiveness in reducing passengers’ injuries and fatality rates. In meeting these requirements, simulations of folding and deploying airbags are very useful and are widely used. The paper presents a simulation method for the deploying airbags using three materials in different working conditions. Finite element analysis is primarily used to evaluate this concept. In these simulations, the gas flow is described by the conservation laws of mass, momentum, and energy. The numerical results indicate that the FE method in this paper is capable of capturing airbag deploying process accurately.

Figure: System Model & Simulation Flow for Ansys Airbag Injury Simulation

Keywords: Airbag simulations, Out-of-position, Crash, Modeling, Out-of-position

Background

The passive safety of cars has become a very high prior- ity issue for the automotive industry. Today, there are not only one or two airbags in a car; certain models have ten times more than that. With the increasing usage of airbags, the number of accidents where the airbag itself can cause an injury to the occupant also increases

(Augenstein Et Al. 2003; Gabauer And Gabler 2010;

Audrey et al. 2011). As is well known, safety belts are also now devices designed to provide protection to the users of vehicles during crash events, minimizing the loads necessary to adapt their movement to the move- ment of the car (Freesmeier and Butler 1999; Schmitt et al. 1997). In general, the seat belt is designed to restrain the occupant in the vehicle and prevent the

Occupant From Having Harsh Contacts With Interior

surfaces of the vehicles. The airbag acts to cushion any impact with vehicle structure and has positive internal pressure, which can exert distributed restraining forces over the head and face. As a safety component of auto- mobile, an airbag decreases occupants’ injury likelihood effectively in case of an accident (Ruff et al. 2007). These safety elements can reduce the death rates on the roads, and its protection effects have been widely approved (Crandall et al. 2001; Teru and Ishikawa 2003). With computational tools such as finite element methods designed for dynamic contact problems, crashworthiness simulations can now be used with reliable accuracy to evaluate occupant protection in various collision condi- tions with safety metric/parameters such as acceleration, head injury criteria, intrusion distance, intrusion vel- ocity, and neck forces (neck injury risk or whiplash).

Figure: System Model & Simulation Flow for Ansys Airbag Injury Simulation

Thus, new types of airbag products are being developed to handle different collision scenarios.

Become Standard Equipment On Most New Passenger

vehicles (Braver and Kyrychenko 2004; Teng et al. 2007; Yoganandan et al. 2007). The airbag cushion is com- posed of a woven fabric which is rapidly inflated during a car crash. The airbag dissipates the passenger’s kinetic energy thereby reducing injury through biaxial stretching of the fabric bag and escaping gas through vents. There- fore, the performance of the airbag is greatly influenced by the mechanical properties of the fabric. Generally, air bags are designed to deploy in a crash that is equivalent to a vehicle crashing into a solid wall at 8 to 14 mph.

Figure: System Model & Simulation Flow for Ansys Airbag Injury Simulation

Air bags most often deploy when a vehicle collides with another vehicle or with a solid object like a tree. There are various types of airbags: frontal, side-impact, and curtain airbags. In general, the passenger side airbags are usually larger than the driver airbags (see Fig. 1).

Figure: System Model & Simulation Flow for Ansys Airbag Injury Simulation

Besançon, France

© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Figure: System Model & Simulation Flow for Ansys Airbag Injury Simulation

Bendjaballah et al. International Journal of Mechanical

Doi 10.1186/S40712-016-0070-2

Extensive studies have shown that the airbag deploy- ment in load cases consists of two occupant loading phases: a punch-out effect where the airbag bursts out of its container with the airbag and airbag module cover accelerating towards the occupant and a second loading phase during which the airbag is taking on its deployed shape and volume (membrane-loading effect). Bankdak et al. (2002) developed an experimental airbag test system to study airbag-occupant interactions during close proximity deployment. The results provided insight for simulating the effect of inflation energy and mass flow on target response. Bedard et al. (2002) found that while left-side (driver-side) impacts accounted for only 13.5% of all crashes, the fatality rate among these

Crashes Was 68.3% In Comparison To Front Impact

(48.3%), right-side impact (31.3%), and rear impact (38.4%). These studies underscore the importance of oc- cupant safety during side-impact collisions. In the last years, the current market requested to reduce the time and cost airbag development. In order to achieve this result, virtual simulations play an important role since they allow to minimize the number of experimental tests (Pei et al. 2013; Cao et al. 2014). Several simulation models of airbag were established (Wang et al. 2007). It is feasible to optimize the parameters of airbag deploy- ment using simulation technology. Experimental and numerical studies have quantified injury risks to close- proximity occupants from deploying side airbags. These studies have focused on the prevention of the most ad- verse effects of airbag deployment (Duma et al. 2003).

Other studies have proposed airbag characteristics to minimize particular biomechanical responses (Haland and Pipkorn 1996). In a more recent study, Marklund and Nilsson (2003) compared deformation patterns with experimental data as well as the computational costs associated with three different airbag deployment simu- lation methods; they concluded that the SPH method is relatively inexpensive and produces incremental deform- ation patterns that compare most closely to the experi- mental results. The process of inflation of an airbag is one of the determining factors in saving lives. The duration from the initial impact of the crash to the full inflation of an airbag is about 40 ms, and during this time, the airbag goes from being in a folded state to a fully inflated state, with a high internal pressure. After achieving this state, the airbag begins to deflate, thus providing a nice cushion for the body impacting it.

Ideally, the person in the crash should come into contact with the airbag at this time. In the present study, a large volume passenger side airbag model is developed to handle different collision scenarios. The main aim is evaluate the performance of deploying of passenger side airbag using finite element methods (FEM).

Materials

The tensile specimens were made in different airbags (P: Peugeot, R: Renault, and VW: Volkswagen) with a length of 200 mm long and a width of 40 mm. Table 1 shows the mechanical properties of the airbag.

Tensile Tests

To determine the mechanical properties of the material of airbag used in the test pieces, tensile tests were performed on Lloyd EZ20 universal testing machine in Constantine. These tests were conducted using rect- angular samples. The axial force and axial displacement acquired during a test are converted into stress and the strain in order to be used for the fabric material model.

The continuous recording of the stress-strain data was performed during both the load and unload phases. A minimum of five samples were made in order to check the repeatability of the measurements. All the data was collected by using a PC-based data acquisition system and analyzed by commercial software. The picture frame test device that is made for this study is shown in Fig. 2.

Fig. 1 a Frontal and side airbags. b Oblique view of facet occupant model in sitting posture following airbag deployment (Lim et al. 2014)

0.150

Bendjaballah et al. International Journal of Mechanical and Materials Engineering (2017) 12:12

Page 2 Of 9

Figure 3 shows the stress-strain relationship of the airbag sample under axial tensile loads. The results are showing a linear increase in extension with the increas- ing stresses. This is an expected output and it confirms with the theoretical behavior of a sample subjected to tensile stress. The rupture strain values for different airbags (R/P/VW) were 0.322, 0.441, and 0.472, respect- ively. The measured elastic parameters (i.e., Young’s modulus E and initial yield strength) and Poisson’s ratio are summarized in Table 2. The tensile tests of the woven fabrics can show differences on mechanical prop- erties because woven fabrics can resist in-plane shear loads once the yarn lock-up angle has been reached. The differences of material property on material direction can affect the shape of fully deployed bag (see Fig. 3b).

Theoretical Background

Numerical simulations of airbags use very complex and techniques such as an orthotropic model to identify the mechanical behaviors during the airbag inflation and the fluid mechanics (gas flow) to describe the inflator gas flow (pressure gradient) and improve the representation of the pressures within the airbag. To model the airbag as an orthotropic model, three material constants have to be provided. Assuming a plane stress condition, the

Ð1Þ

where σ is the normal stress and τ is the shear stress, the subscript refers to the principal material directions, i.e., the fill and warp directions. Also, ε and γ are the strain components. The material elastic constants Qij are

Ð2Þ

where E1 and E2 are the Young’s modulus in the fill and wrap directions and G12 is the shear modulus of the fabric material. νij is the Poisson ratio of the material.

The gas exerts a pressure load on the airbag causing it to expand. This expansion puts the airbag under tensile stress lowering the expansion rate. In this study, heat conduction and heat transfer is not taken into account.

Fig. 2 A photograph of Lloyd EZ20 universal testing Fig. 3 Stress versus strain using Lloyd EZ20 machine for a three different airbags at 0° and 90° and b VW airbag test specimens at

Different Angles

Table 2 Physical and mechanical properties of the airbag

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In the deployment of an airbag, an inflator supplies high velocity gas into an airbag causing it to expand rapidly. The gas inside the airbag is assumed to be ideal, to be of constant entropy, and to satisfy the equation of state:

Ð3Þ

Here p, ρ, and e are respectively the pressure, density, and specific internal energy, and γ is the ratio of the heat capacities of the gas. The gas flow is described by the conservation laws for mass, momentum, and energy that

Ð4Þ

here, V is a volume, A is the boundary of this volume,

N Is The Normal Vector Along The Surface A, And U

denotes the velocity vector in the volume. Applying Bernoulli’s equation in the case of an ideal gas with

Ð5Þ

Here, the subscript ex denotes quantities at the throat of the tube. Furthermore u, p, and ρ denote the quan- tities inside that part of the tube that is supplying mass.

Materials And Boundary Conditions

The airbag system mainly consists of three parts: the airbag itself, the inflator unit, and the crash sensor or diagnostic unit. Thus, to study the behavior of the airbag using FE simulations, we need to have an FE model of the airbag in the folded position. A FE model of the airbag was used to simulate the test condition as shown in Fig. 5. LS-DYNA® material model FABRIC (MAT_34) is used to simulate the airbag material. It is a variation of the layered orthotropic material model. Additionally, in the LS-DYNA® material model, fabric leakage can be accounted for. However, for this CAB material, the leak- age is almost negligible and therefore no leakage is specified. The mechanical properties can be determined from the physical test. Typical material properties for airbag fabrics are taken as given in Chawla et al. (2004a) (Table 3). These properties are used to simulate inflation process of airbag (see Table 1). The car dashboard is modeled as the rectangular thin plate using a MAT_RI-

Gid Material, And The Degrees Of Freedom Are Con-

strained in all the directions. The similar properties of thermoplastic polymer are assigned for contact purposes. The porosity of the fabric is assumed zero. The nitro- gen gas is taken for inflating the airbag. Properties of nitrogen gas and initial bag conditions are shown in Table 4. The example on which we perform the study is a typical passenger side airbag. The geometric de- tails have been measured from a commercially avail- able airbag. The initial state of the airbag is a closed rectangular whose sides are to be finished to 482 × 635 mm2 and is shown in Fig. 4.

Table 3 Material properties of airbag and rigid plate used in FE

–

Table 4 Initial values used for FE simulation of the swelling of

3.33 × 10−4

Fig. 4 The initial airbag geometry in the form of a rectangular Bendjaballah et al. International Journal of Mechanical and Materials Engineering (2017) 12:12

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