Nt1210 Lab 5.5

Fig. 9(a) shows the DC-link voltage across the DC-link capacitor of the PV array. The DC-link reference voltage corresponds to maximum power point of the PV array. Fig. 9(b) shows the power demand by the load, and power flows from the grid and PV system generated power. As the PV system generated power could not meet complete power demand of load, remainining power is supplied by the grid. At 1secocond the PV system switched from partially shaded condition to uniform solar insolation. Thus, at this point power supplied by the inverter and grid also varies. Fig. 10(a) shows the grid current which is fully sinusoidal. Fig. 10(b) shows the inverter output current. Fig. 11 shows the performance of system under reactive load condition. In this study, a 500VA reactive load is considered. The figure shows the complete reactive power is supplied by the inverter. Thus the power factor of the system is maintained nearly at

It is observed that the power factor is maintained closer to unity when the input voltage is reduced from 230V to 110Vrms. Figure 11 (a) and (b) shows the power factor correction of controller for various load condition such as 20% (60W) and 75% (230W). The power factor for the system is found to be 0.84 for light load condition and 0.99 for full load condition. The THD of input current at full load with predominant third and fifth harmonic components are shown in Figure 12(a) and (b).Third harmonics is found to be 4.8% and fifth harmonic component is 4.9% which are well within IEC 61000-3-2 standard during wide range of load variations. The variation in power factor with load is shown graphically in Figure 13(a). It can be inferred from the graph that improved resettable control operates at high power factor for all load condition whereas the conventional PI control has poor power factor under light load conditions. Figure 13(b) shows the comparison between the efficiency of the converter for varying load conditions with the conventional control method and the resettable integrator control. The converter’s efficiency is maintained at 92% for light load conditions and 96% for fully loaded condition with integrator control technique. Thus the improved resettable integrator controller provides a very simple and reliable solution for power factor correction and

The reactive power supplied by the STATCOM for DF improvement is capacitive in nature. Instinctively, the higher the STATCOM’s reactive power, the higher the dc-link voltage of the STATCOM (the higher the voltage requirements of the semiconductor devices).

In this paper, a hybrid VSC-MMC based HVDC transmission system supplying a passive load is investigated. Fig.1 shows the basic configuration of the Hybrid HVDC Transmission system. It consists of a VSC connected to the sending-end AC network, and a MMC connected to the receiving-end network.

Change of converter operating point upon switching: The influence of AC voltage change on firing angles and tap-changer controls.

For the traditional voltage source PWM inverter, we have the well-known relationship: . Equation (10) shows that the output voltage can be stepped up and down by choosing an appropriate buck–boost factor BB,

Abstract— this paper presents a brief overview of standards for power electronics. All the standards presented in this paper are currently active and are approved by the Institute of Electrical and Electronics Engineer Standards Association (IEEE-SA) and American National Standards Institute (ANSI).

This project represents a robust feedback linearizing stabilization scheme for a three phase grid connected PV (Photovoltaic) system with boost converter to control the injected current into the grid and DC link voltage to generate more power from photovoltaic (PV) modules. In this proposed system, boost converter is implemented with the photovoltaic system to increase the input voltage to output. The proposed control scheme is mostly based on the robust controller with partial feedback linearization approach of response and the robustness of the proposed control scheme is ensured by in view of uncertainties within the photovoltaic structure. The uncertainties are modeled as structured uncertainties based on the approval of corresponding circumstances are proposed in this work. The proposed robust control linear stabilization scheme is implemented on a photovoltaic three phase grid connected system with boost converter in terms of delivering maximum power under changes in different atmospheric situations. The implementation and analysis of three phase grid connected photovoltaic system with boost converter by using MATLAB/Simulink software.

Abstract: The power quality (P.Q) arise mainly due to the PE equipment’s. In this paper presents the difference of simulation study of PI controlled based STATCON (STATCOM also called be STATCON) and shunt active power filter (SAPF). So, in order to improve the P.Q by sending or receiving the reactive power relay upon the necessity for load. And migrates the harmonics by injecting current into the scheme. So, that total harmonic distortion value of source current is decreased.

Balanced current sharing between the two three-phase windings {1} and {2} can be realized in post-fault con¬ditions by simply setting ki = 1/2. Power (voltage) sharing co-efficient kv(2) to synthesize v(2) between inverters VSIH(2) and VSIL(2).

The above figures (Figure 3.5 to 3.8) show the response of PI controller for islanding and non- islanding conditions. The figures clearly show that the use of PI controller is more prominent for islanding condition than the non-islanding (normal) condition to settle large steady state oscillations to lower value in case of islanding events. This significantly improves the dynamic performance of a grid-connected PV system.

Power electronic converters, especially DC/AC inverters have been extending their range of use in industrial application because they provide better system efficiency, reduced energy consumption and improved quality of power. The output voltage of inverter could be fixed or variable at a fixed or variable frequency and output waveforms are therefore made up of discrete values, producing fast transition

A DC-DC converter is a device used to obtain variable d.c. voltage from a source of constant d.c voltage .Therefore it may be thought of as d.c equivalent of an a.c transformer. Since they behave in an identical manner .Besides the saving in power, the d.c choppers offers greater efficiency, faster response lower maintenance, small size, smooth control and for many applications, lower cost than motor generator sets or gas tubes approaches.

The controller for the SSSC can be isolated, generally, into two main controllers, namely internal and external controllers. The main function of the internal controller is to give the control signal to drive the gate pattern generator of the power converter keeping in mind to generate a fundamental output voltage waveform with the desired magnitude and phase angle in synchronism with the ac power system. The function of the external controller, if exists, is to alter the reference signals which decides the practical operation of the SSSC so as to accomplish the desired system performance. The block diagram of the SSSC controller is represented in Figure 3.13.

The main aim of automatic voltage regulation system is to hold terminal voltage constant. The characteristics of alternator output required are constant voltage and constant current. To get the