Abstract: - The emergence of multilevel inverters has been in increase since the last decade. These new types of converters are suitable for high voltage and high power application due to their ability to synthesize waveforms with better harmonic spectrum. Numerous topologies have been introduced and widely studied for utility and induction billet applications. In this paper, proposed a Modified Multilevel Inverter (MMI) is eleven Levels. This proposed MMI consists of less number of switches to attain eleven levels when compared to the traditional cascaded multilevel inverter to attain the same level. As a result, voltage current stress across switches gets reduced, so that power loss gets reduced in the system. Secondly, an effective pulse width modulation (PWM) approach that can be utilized successfully with high control accuracy is combination of selective harmonic elimination and pulse width modulation (SHEPWM).This technique offers many advantages other PWM techniques including direct control over output waveform harmonics, and the ability to eliminate third, fifth and seventh order harmonics.
Abstract: In several PWM DC-DC converter topologies, the controlling switches are operated in switch mode wherever they're needed to conduct the whole load current on and off throughout every switching cycle. Recently there is an enlarged interest within the use of resonant kind DC-DC converters due to the benefits of high efficiency, small size, lightweight, reduced Electro Magnetic Interference (EMI) and low component stresses. A novel PFC (Power factor Corrected) converter feeding a PMSM drive employing a single voltage sensing element is proposed for variable speed applications. It consists of single phase supply followed by uncontrolled bridge rectifier and a Zeta DC-DC converter is employed to regulate the voltage of a DC link capacitance that is lying between the Zeta converter and a VSI (Voltage source Inverter). The voltage of a dc-link capacitor of zeta converter is controlled to realize the speed control of PMSM Drive. The zeta converter is functioning as a front end device operating in DICM (Discontinuous inductor Current Mode) and therefore employing a voltage follower. Using MATLAB/ Simulink 7.13 environment the model can be simulated to achieve a wide range of speed control.
Abstract: Previous research was mainly concentrated on eliminating the selected lower order harmonics depending on the level of inverter which was assumed to be high. The harmonics may be present even in the higher order also. The analysis of harmonic spectrum by Finite Fourier Transform yields a very accurate result for lower order harmonics. For obtaining accurate Total Harmonic Distortion (THD) value and the harmonic spectrum, inclusion of higher order harmonics is essential. The method for accurate estimation is proposed in this paper. In normal practice, the higher order harmonics present in the output of the inverter are suppressed by using filters. In order to obtain more optimized higher order harmonics, it is necessary to obtain an accurate assessment of the higher order spectrum. The higher order spectrum is predetermined by proposed technique termed as Dual Phase Analysis (DPA) so as to obtain more optimized switching angles with the application of any Optimization Technique. This is an effective tool to analyze the various higher order components of the harmonic spectrum.
Abstract: The idea orients to develop a PI controller for closed loop speed control of chopper fed dc drive. PI controller is one of the most preferred controller for speed control of dc drive, which can be easily understood and implemented in practice. The speed of the chopper fed separately excited dc motor can be regulated from below and upto rated speed by using a chopper as a converter. The signal corresponding to the speed error of the motor and change in speed error are given as inputs to the PI controller. The controller output provides the required gating signal that is used to vary the duty cycle of chopper. The chopper firing circuit receives signal from controller, gives variable voltage to the armature of the motor for achieving desired speed response. Modeling of chopper fed dc motor is done. Two loop control system is designed, one for current and another for speed. The complete model of proposed system is simulated using MATLAB (SIMULINK). Also the performance of the simulated model is investigated by using various controller tuning methods.
Abstract: To improve the tracking capability of the PV, soft computing technique is used to utilize the PV power effectively. Here, DPSO is used to maximize the PV power. In this paper Performance of SEPIC converter compared with buck-boost converter under both normal and partial shading conditions of PV system. This paper gives the new intelligent control technique in order to track the global maxima of PV power effectively and also gives MATLAB-Simulink to control the system parameters via DPSO method.
Abstract: This paper presents a Hardware implementation of single-stage solar based DC-DC converter for inductive load application. Solar model is connected in the input side. The circuit has two full wave converter connected to boost the voltage and also for the power factor correction. Switch-utilization factor is improved by using two active switches to serve in the PFC circuits. Controlled converter is used to load side along with pi filter. Finally inductive load is connected to output side. In the hardware circuit solar panel output voltage, transformer primary, secondary voltage and load voltage is measured. In the circuit used with all the component parameters to operate at zero-voltage switching which retains the high circuit efficiency. A circuit is designed for an 80v dc output and tested.
Abstract: Positive output Re-lift luo converter is a recently developed DC-DC converter which performs the conversion from positive source voltage to positive load voltage and are used in computer peripherals, dc drives, industries and other high voltage projects.Voltage lifting technique is employed and hence the output voltage increases in an arithmetic progression unlike classical boost converter. This paper presents the closed loop control of positive output re-lift luo converter with PI controller.PI controller is capable of providing good static and dynamic performances and can be used to analyze the system performance under disturbances.Control algorithm such as Cuckoo and Particle Swarm Optimization are implemented to track output voltage with respect to the reference voltage.These optimization techniques rejects the system disturbances at line and load side, hence steady state can be reached with less overshoot and settling time.The simulation model of the proposed converter is implemented in Matlab/Simulink and Cuckoo technique is compared over PSO.
Abstract: This paper presents a comparative study on performance of conventional PI controller and fuzzy controller on three phase, three wire voltage source inverter based shunt active filter that is used to compensate the harmonics currents drawn by non-linear loads in distribution systems. Hysteresis PWM method is used to generate the pulses to the switches used in active filter. The compensation is based on PLL method of fundamental current extraction. The nonlinear load taken into account is a three phase diode bridge rectifier.
Abstract: This paper proposes a high efficient advanced DC-DC converter by name Triple-Lift converter in the front end of Induction motor (IM) drives system. The conventional IM drives use PWM rectifier, boost converter, buck-boost converter, etc., in the front end which holds inadequacy in pump-up voltage and deprived output current. The Triple-Lift converter (TLC) implemented in the system employs voltage lift technique and produces the output voltage in arithmetic progression. The voltage source inverter (VSI) coupling IM derives a wide range of DC input (ripple free) from TLC which can be adopted for high rated motors with good efficiency. Simulation results using MATLAB show the effectiveness of the proposed converter arrangement for IM drives.