Comparison of single-phase transformerless photovoltaic grid-connected inverter topologies with high efficiency and low ground leakage current

When a transformer is taken out of a photovoltaic (PV) inverter system, the efficiency of the whole system can be improved. Unfortunately, the additional ground leakage current appears and needs to be considered. The problem of ground leakage current is that it poses an electrical hazard to anyone touching the photovoltaic (PV) array's surface. For safety issues, the ground leakage current should be less than 300 mA, which follows the VDE-0126-1-1 German standard. To minimize the ground leakage current in the transformerless PV grid connected inverter system, the proposed inverter topologies (SC-HB inverter, bipolar H-Bridge inverter with CD-Boost converter, modified unipolar HBridge inverter with CD-Boost converter and modified unipolar H-Bridge inverter with modified boost converter) are analyzed, verified and compared in this thesis. In order to analyze the effect of unbalanced filter inductance on the transformerless bipolar H-Bridge inverter topology, the matching ratio of inductance :Lr = Lfl/Lfln and L12IL12n ) is investigated. In addition, the effect of parasitic capacitance value on the transformerless bipolar H-Bridge inverter topology is studied. The effect of modulation techniques using bipolar SPWM and unipolar SPWM on the transformerlcss H-Bridge inverter topology is compared and analyzed in terms of common-mode voltage and ground leakage current. TMS320F28 I 2 is used as a controller to generate the PWM control signal, maximum power point tracking (MPPT) based on power balance and Proportional-Integral (PI) controller. PSIM 9.0 simulation software is used to design the proposed transformerless inverter topologies. Simulation and experimental results verified the proposed inverter's feasibility in addressing issues of transformerless DC/ AC converters in grid-connected PV systems

Development Of Software System For Detecting Defective Symbol On IC Chip Using Matrox Imaging Library

In semiconductor fabrication process, symbol or label inspection is one of the main processes that needs to be considered seriously. Errors may occur during the printing process of label or name on the integrated circuit chip (IC). If this occurs, the IC chip may have a wrong name. This will affect the credibility of the company who produces the IC chips. The problem mentioned above can be solved by providing a reliable detection system that is able to detect the errors printed on the IC chip. The symbol detection system that currently being implemented by the semiconductor industry suffers from over killed and escapes problems. This project presents the development a software system, which capable of detecting the defective characters printed on the IC chip using Active Matrox Imaging Library Release 7. The proposed system has an adjustable reading level that can solve the overkilled and escaped problems. It consists of a graphical user interface module, an inference engine, an image database, an ActiveMIL ActiveX control module, a Matrox Imaging Library module, an input image, and an output image. The proposed system is written in Visual Basic version 6 and it is interfaced with Active Matrox Imaging Library. The proposed system also has learning capability. It can store up to two different IC images at one time. The system was designed for off-line operation. The test results demonstrated that the proposed system performs according to its functions. It achieves 100% detection rate

Simple MPPT Technique for DC-DC Converter In Fuel Cell System

This paper presents the simulation of fuel cell mathematic model interfaced with DC- DC boost converters. The drawbacks of the fuel cell stack are that it lacks maximum power to generate the suitable application and high input current ripple. So, the maximum power point tracking (MPPT) technique of voltage constant controller is implemented to the system to extract the maximum power from the fuel cell. The MPPT technique forces the fuel cell to meet the maximum power that the fuel cell can generate. This MPPT method increases the efficiency of power delivered from the fuel cell. The benefits of the converter chosen are the interleaving technique used in converter reduced the current ripple that could damages the fuel cell stack. The converters chosen is the conventional dc boost converter and interleaved boost converter that will be simulated along with the MPPT algorithm in MATLAB/Simulink environment. The interleaved boost converter has also chosen for its advantages of reduction of passive component's size, as well as reduced the current ripple. It is proved that the MPPT method of constant voltage gives a stable and linear performances in designing a high efficient fuel cell system

Simple MPPT Technique for DC-DC Converter In Fuel Cell System

This paper presents the simulation of fuel cell mathematic model interfaced with DC- DC boost converters. The drawbacks of the fuel cell stack are that it lacks maximum power to generate the suitable application and high input current ripple. So, the maximum power point tracking (MPPT) technique of voltage constant controller is implemented to the system to extract the maximum power from the fuel cell. The MPPT technique forces the fuel cell to meet the maximum power that the fuel cell can generate. This MPPT method increases the efficiency of power delivered from the fuel cell. The benefits of the converter chosen are the interleaving technique used in converter reduced the current ripple that could damages the fuel cell stack. The converters chosen is the conventional dc boost converter and interleaved boost converter that will be simulated along with the MPPT algorithm in MATLAB/Simulink environment. The interleaved boost converter has also chosen for its advantages of reduction of passive component's size, as well as reduced the current ripple. It is proved that the MPPT method of constant voltage gives a stable and linear performances in designing a high efficient fuel cell system

Investigation Of Different Rules Size FLSC Performance Applied To Induction Motor Drive

Fuzzy Logic Controller (FLC) has been widely used in speed controller due to its superior performance results. It is suitable when the system is difficult to model mathematically due to its nonlinearity and complexity. There are three common number of rules design which are commonly used in FLSC known as 49, 25 and 9 rules. However, the majority of the previous research report mainly focused on the dedicated rules size design either 49, 25 or 9 rules for the optimum performance. There is lack of performance comparison between 49, 25 and 9 rules size. Thus, it is difficult to understand how the rules size affects the motor performance. This research tries to fill up the gap by comparing the controller performance using the same platform. The fuzzy logic speed controllers (FLSC) with a different type of rules base are applied to the induction motor drive system. The FLSC with 49, 25 and 9 rules are investigated through MATLAB/SIMULINK and performance comparisons are made covering a wide speed range operations and load disturbance. The simulation results are evaluated based on the rise time

A New Improvement of Reverse Voltage Single Phase Multilevel Inverter Topology

The widely use of a multilevel inverter (MLI) in high power system applications proves that MLI is highly superior to the conventional inverter in reducing harmonic distortion. Basically there are three topologies of multilevel inverters that commonly used, which is cascaded H-Bridge, diode clamped and flying capacitor. Even though these inverters can produce low harmonic distortion, many switching devices are needed to perform high voltage level. However, the usage of a numerous number of switching devices can produce high switching losses. It also increases weight, space, cost and switching complexity of the hardware. Therefore, this study attempts to develop low harmonic distortion with less switching devices by improving the reverse voltage topology using MATLAB/Simulink software. The performance of proposed scheme was evaluated through an extensive test considering several scenarios such as amplitude modulation ratio (Ma), total harmonic distortion (THD) and switching scheme under various operating points. Moreover the effectiveness of the proposed scheme was verified by comparing its result with conventional MLI such as reverse voltage MLI topology and cascaded H-bridge topology

Speed and position estimator of for sensorless PMSM drives using adaptive controller

Nowadays, the elimination of the speed sensor in Permanent Magnet Synchronous Machine (PMSM) is greatly recommended to increase efficiency and reduce the cost of the drives. This paper proposes a simple estimator for speed and rotor position of PMSM drives using adaptive controller. The novelties of the proposed method are the simple estimator equations and the absence of the voltage probe which depend on direct and quadrature reference current only. The simplified mathematical model of the PMSM is formulated by using V-I model, based on adaptive control. Then, the speed estimation error of the voltage and current model based are analyzed. Thus, an adaptation mechanism model is established to cancel the error of the measured and estimated d-q currents. Since the output of the estimator is the position feedback, the performances of speed responses are presented. The hardware implementation of proposed sensorless drives is realized via dSPACE DS11103 panel. dSPACE Real Time Implementation (RTI) is the linkage between software and hardware set-up. It automatically processes the MATLAB Simulink model into dSPACE DS11103 processor. The experimental-hardware results demonstrate that the speed and position estimator of the proposed method is able to control the PMSM drives for forward and reverse of speed command, acceleration, deceleration and robustness to load disturbanc

Comparison of single-phase transformerless photovoltaic grid-connected inverter topologies with high efficiency and low ground leakage current / Maaspaliza Azri

When a transformer is taken out of a photovoltaic (PV) inverter system, the efficiency of the whole system can be improved. Unfortunately, the additional ground leakage current appears and needs to be considered. The problem of ground leakage current is that it poses an electrical hazard to anyone touching the photovoltaic (PV) array’s surface. For safety issues, the ground leakage current should be less than 300 mA, which follows the VDE-0126-1-1 German standard. To minimize the ground leakage current in the transformerless PV grid connected inverter system, the proposed inverter topologies (SC-HB inverter, bipolar H-Bridge inverter with CD-Boost converter, modified unipolar H-Bridge inverter with CD-Boost converter and modified unipolar H-Bridge inverter with modified boost converter) are analyzed, verified and compared in this thesis. In order to analyze the effect of unbalanced filter inductance on the transformerless bipolar H-Bridge inverter topology, the matching ratio of inductance (Lr = Lf1/Lf1n and Lf2/Lf2n ) is investigated. In addition, the effect of parasitic capacitance value on the transformerless bipolar H-Bridge inverter topology is studied. The effect of modulation techniques using bipolar SPWM and unipolar SPWM on the transformerless H-Bridge inverter topology is compared and analyzed in terms of common-mode voltage and ground leakage current. TMS320F2812 is used as a controller to generate the PWM control signal, maximum power point tracking (MPPT) based on power balance and Proportional-Integral (PI) controller. PSIM 9.0 simulation software is used to design the proposed transformerless inverter topologies. Simulation and experimental results verified the proposed inverter’s feasibility in addressing issues of transformerless DC/AC converters in grid-connected PV systems

Transformerless Power Converter For Grid-Connected PV System With No-Ripple Input Current And Low Ground-Leakage Current

The application of boost converters is highly favored in PV module integrated converter (MIC) systems.The conventional boost converter operating in continuous inductor-current mode (CICM),however,has a pulsating, high-ripple input current,which causes power loss and decreases the energy flowing from non-linear sources like the PV panel.Therefore,this paper proposes a new modified boost converter that has a no-ripple input current.The proposed converter uses a series of input inductance to produce zero-ripple input current during continuous inductor-current mode,without any LC or C filter elements.It is capable of high power-conversion efficiency for the whole system without the use of any transformer or galvanic isolation components.In addition, this proposed boost converter is integrated with an H-Bridge inverter for a transformerless PV grid-connected system.The issue of electrical safety of the high ground-leakage current (due to the parasitic capacitance of the PV panel and frame and lack of galvanic isolation) is resolved by bipolar SPWM technique in the H-Bridge inverter,without any additional hardware.The proposed DC-AC transformerless inverter grid-connected PV system, which has a new modified boost converter and bipolar H-Bridge inverter,is verified by a 1-kW hardware prototype simulated and validated by experiment.The results show zero-ripple input current,high power-conversion efficiency,near-unity power factor,low current-THD,and low ground-leakage current