Disadvantages And Disadvantages Of Multilevel Inverters Used In Conventional Inverter

The innovative inverter technology produces safe, smooth power, protecting your sensitive electronics (computers, smartphones, etc.) from damage.

Switching power converters offer an easy way to regulate both the frequency and magnitude of the voltage and current applied to a motor shown in fig(1). As a result much higher efficiency and performance can be achieved by these motor drives with less generated noises[3].

Now a days, the switching power supply market is flourishing quickly. The trend is for DC-AC converters with low cost, higher efficiency, power saving that enable maximum features. In this project, a single-stage three-switch buck-boost inverter is designed, where stepping up, stepping down and inversion operation will takes place in single stage. This proposed inverter will overcome all the drawbacks of traditional one. Coupled inductor plays a very important role in energy transfer and eliminates the use of line frequency transformer. As the inverter having only three switches, the controlling of switches also easier than conventional one. And it has also advantages like compact design, reduced switching losses, component size, and cost.

Abstract: The area of the multiphase motor has experienced a significant growth in last decade numerous interesting development have been reported in the literature in this chain this paper is an attempt to mathematically model both three phase and six-phase induction motor for comparison of their characteristics. Using this mathematical modeling a Simulink model is created whose results shows that the six-phase induction motor can sustain more than four times the torque that can be sustained by three phase induction motor of same design parameters. The six-phase motor is better not just in torque handling capacity but it also has inherent advantages of the multiphase induction motor.

In this chapter, an overview of the state of the art system of an induction motor is carried out. It looks at various induction motor control methodologies utilizing current and voltage control to control the flux and the torque of the dynamic system. Highlight of the current and future challenges of induction motor drives are presented. To do that, a general principle of induction motor drives is discussed first follow by phase controlled of induction motor drives, frequency controlled of induction motor, and vector controlled of induction motor.

To study the impact of VSFPWM on switching loss reduction over the entire modulation index range, the simulations were carried out different speeds (modulation indices) for a constant load torque. Table II and Table III compares the current ripple, and the percentage change in the current distortion and the switching losses for CSFSVPWM-VSFSVPWM and CSFDPWM2-VSFDPWM2 techniques respectively. Similar to the analytical results at section II, there is higher switching loss reduction capability at higher speed due to higher variation in current ripple at higher speeds (modulation indices). For example, with VSFSVPWM, around 15% switching loss reduction is obtained, whereas with VSFDPWM2, around 7.2% switching loss reduction is obtained. The difference in switching loss reduction capability in comparison to analytical results is attributed to the

Space Vector PWM (SVPWM) refers to a special switching sequence of the upper three power transistors of a three-phase power inverter. It has been shown to generate less harmonic distortion in the output voltages and or currents applied to the phases of an AC motor and to provide more efficient use of supply voltage compared with sinusoidal modulation technique. The biggest difference from other PWM methods is that the SVPWM uses a vector as a reference. This gives the advantage of a better overview of the system.

For reverse voltage blocking a diode is used in series with the self-commutating device (IGBT) . However, GTO-based configurations have restricted frequency of switching they do not need the series diode. They are considered sufficiently reliable, but have higher losses and require higher values of parallel ac power capacitors. Moreover, they cannot be used in multilevel or multistep versions to improve performance in higher ratings.

This thesis deals with the configuration and investigation of control framework structures for electric drives furnished with changeless magnet synchronous machines (PMSM) in car application. With the expanding prominence of multi-level inverters, the opportunity to get better of the execution of voltage source inverters has persistently been tried for different applications. The fast improvement of high exchanging recurrence power gadgets in the previous decade leads towards more extensive use of voltage source inverters in AC power era. In this way, this prompts the requirement for a regulation method with less aggregate symphonious bending, less exchanging misfortunes, and more extensive direct balance range. The present theory highlights the examination of the customary two-level inverter and the three-level diode cinched inverters for the application in car industry.

PWM inverters are used for a wide range of applications such as: Adjustable Speed Drives (ASD), Power Filters (PF), Dynamic Voltage Restorers (DVR), Uninterruptable Power Supplies (UPS) and Distribution Static Compensators

This project is aim to study the principle of pwm, single-phase inverter, three-phase inverter which leading to design a three-phase inverter(DC-AC) by using the mbed to control switch. This inverter will be intended to drive an induction motor which may need to drive. The work will involve simulation study of PWM generators, induction motors and device selected from.

Multilevel inverters have ability to generate low switching frequency high quality output waveforms with several high voltages and high power applications. The general structure of the multilevel converter to synthesize a

Fig.3.11 Schematic diagram of switching logic for single-phase three-level SPWM converter (u is the input signal for the corresponding block, not the global signal)

Generation of electrical power in low voltage level is very much cost effective. Hence electrical power is generated in low voltage level. Theoretically, this low voltage level power can be transmitted to the receiving end. But if the voltage level of a power is increased, the current of the power is reduced which causes reduction in ohmic or I2R losses in the system, reduction in cross sectional area of the conductor i.e. reduction in capital cost of the system and it also improves the voltage regulation of the system. Because of these, low level power must be stepped up for efficient electrical power transmission. This is done by step up transformer at the sending side of the power system network. As this high voltage power may not be distributed to the consumers directly, this must be stepped down to the desired level at the receiving end with the help of step down transformer. These are the uses of electrical power

The conventional two levels Inverter have many limitations for high voltage and high power application. Multilevel inverter becomes very popular for high voltage and high power application. The multilevel inverter is started with the three level converters. The elementary concept of a multilevel converter to achieve higher power to use a series of power semiconductor switches with several lower voltage dc source to perform the power conversion by synthesizing a staircase voltage waveform. However, the output voltage is smoother with a three level converter, in which the output voltage has three possible values. This results in smaller harmonics, but on the other hand it has more components and is more complex to control. In this paper, study of different three level inverter topologies and SPWM technique is explain and SPWM technique has been applied to formulate the switching pattern for three level and five level H-Bridge inverter that minimize the harmonic distortion at the inverter output. This paper deals with comparison of simulation results of three levels and five