PERFORMANCE ANALYSIS

PERFORMANCE ANALYSIS

In this chapter, the performance implementation of  a NOVEL FRAMEWORK APPROACH WAS ANALYZED.

Figure 5.1 Simulink design of proposed method

In the first stage of the research work, the MATLAB Simulink model of the proposed system is designed with PV panel array, wind power system, a Fuzzy logic controller with Incremental Conductance method and Elephant Herding Optimization that is controlled by the power converter and given to the load shown in figure 5.1.

The Simulink model of the proposed EHO optimization technique is shown in Figure 5.2. Photovoltaic or PV modules and wind power systems are interconnected with the CukSepic Converter to the load or distributed grid side. For improvement in the Efficiency of the System, PV array needs MPPT. This paper proposed a FEHO MPPT modelling and control of the hybrid wind-PV system. Generally, the MPPT is achieved by interjecting a CukSepic converter between the PV module and the load, thus, controlling the converter duty cycle (D). The results show an optimized output which will be explained in the next chapter. This model is simulated in various partial shading conditions in the MATLAB/Simulink.

Figure 5.3 Simulation of Fuzzy with EHO method

Under various irradiance conditions, the simulation results are predicted. The PV array response is measured by the rapid change in isolation which is given to the PV module as intensity pulse. Using the Beta method, the maximum power point is tracked effectively under the rapid change of isolation. Hence the results are simulated as given below.

Figure 5.4 Current-Voltage characteristics

Figure 5.4  and 5.5  illustrates the I-V and P-V characteristics of the PV array under partial shading conditions. The P-V and I-V characteristics of a Solar cell, PV array, or module show detailed information about the efficiency and ability of solar energy conversion. The curves render the details needed for the configuration of a solar energy , such that the system operates as close to the optimal peak as possible. The difficulty deliberated by MPPT procedures is to habitually discover the voltage VMPP or current IMPP at which a PV array must function to get the maximum power output PMPP below a specified temperature as well as irradiance. It is probable to have multiple local maxima, but generally, there is only one MPP. Most of the procedures react to fluctuations in both irradiance as well as temperature, but some are precisely more beneficial if the temperature is almost constant.

                            Figure. 5.5 Power – Voltage characteristics

Figure 5.5 depicts the input power tracking response of the output power obtained from the proposed Fuzzy-EHO based Cuk Sepic Converter under partial shading conditions. This shows the maximum power tracked by the proposed MPPT based Cuk Sepic Converter.

Figure 5.6 Power Tracking Response under partial shading condition

Figure 5.7  Inverter Vab voltage waveform before the filtering process

Figure 5.7  shows the inverter output voltage between the phases a and b, and it has the magnitude of -280 to 280. By using the LC filter, this is changed to a sinusoidal output, and it is shown in figure 5.20.

Figure 5.8 Inverter lab voltage waveform after the filtering process

Figure 5.9 Simulated result of Load Voltage of the PV-Wind System

Figure 5.9 shows the load side output voltage of the proposed system. Even with the dynamic conditions, the sinusoidal output is provided by the proposed control strategy.

Figure 5.10 shows the output voltage at the DC link of the inverter terminal. It shows that even with the variation in the power sources the DC link voltage is maintained at a constant level of 300V. This will improve the reliability of the hybrid wind-solar system.

Figure. 5.10 Simulated results of DC-link voltage

Figure 5.11 Simulated and the experimental I-V curves without shading and simulated with shading.

Figure 5.11 shows the comparison between the load side output voltage and current of the PV-system with and without shading. A shaded solar cell is like a clog in a pipe. The current flowing through an entire string module can be reduced.

Figure 5.12 Simulated and the experimental P-V curves without shading and simulated with shading.

Figure 5.12 shows the comparison between the load side output voltage and power of the PV-system with and without shading. The step size of the PV System modulation index is changed so that the fast MPP (Maximum Power Point) tracking can be performed, but the oscillation power around MPP will be large. In contrary, it changed to long tracking time and small oscillation when step size is small.

Figure 5.13 THD analysis of load voltage

Figure 5.13 shows the Total Harmonic Distortion (THD) analysis of the load voltage waveform. It showed that even with the variation in the load and source side, the THD of the proposed hybrid system is very low.

Table 5.1 Performance Comparison of MPPT Methods

From Table 5.1, it is noticed that the Proposed Fuzzy Logic Controller based EHO has better system performance in maximum power point conditions. The method of MPPT based FLC standard slows down in tracking the maximum available PowerPoint when the radiation level is changing very fast whereas the second method FEHO rectifies this problem. The MPPT efficiency has been increased from 99.89% to 99.95%, and the accuracy is further increased by 0.33 seconds to 0.19 seconds respectively, and this proves that the FEHO is applicable to achieve the optimized value.

The results are taken through the implementation of Matlab/Simulink and ATMEGA8 microcontroller respectively. The output diagrams related to pulse width modulation is displayed in the following three diagrams. The voltage and current waveforms for the three type of MPPT techniques are given. The next section gives the resultant analysis of hardware implementation with the pulse performances of switches. Figure 5.14 shows the results of Phase Disposition PWM.

Figure 5.14 Phase Disposition PWM

Every bearer will have equal amplitude and frequency each N-1 bearer are in a condition with one another. This process depends on the variation of sinusoidal insinuation waveform with diagonally moved bearer waveform. Every bearer signals in phase have equal amplitude and equal frequency. This process will also relevant to diode clamped inverter.

In the phase opposition disposition the bearer is over the zero insinuation are in phase but moves to 180⁰ under the zero insinuation were the POD replacement bearers are organized in 180⁰ phase change

Figure 5.15 Phase opposition disposition PWM

Figure 5.16 Phase shift PWM

Every bearer signal will have equal frequency and amplitude else they are phase changed by 90⁰ by one another. The number of counts of all bearer is judiciously phase changed. Figure 5.15  and Figure 5.16 represents the results of Phase opposition disposition PWM and the Phase Shift PWM.

Figure 5.17 seven levelled DC-link multilevel inverter simulation diagram

The output of the simulation is consummated by the MATLAB/SIMULINK. The above fig represents the seven levelled DC-link multi-level inverter. The all three PV functions have accomplished as 49 V performed by the PV system, which will be linked with DC-link MOSFET based inverter. The next process of emerging current and voltage waveform will be explained in the below diagrams. Figure 5.17 represents the seven levelled DC-link multilevel inverter simulation diagram

Simulation Output Waveforms

The output waveforms of seven-level DC-link inverters like voltage and current waveforms for varied PV sources like PV1, PV2 and PV3 at non-luminosity stages will be explained in given below waveforms.

Modified p&o Algorithm

Figure 5.18 voltage and current output waveform

Figure 5.18 represents the voltage and current waveforms for varied PV sources at different ranges. In this the range for all PV sources are same like, PV1=1000 w/m², PV2 = 1000 w/m² and for PV3 = 1000 w/m². The output range for both voltage and the current waveform is equal for modified p&o algorithm.

Incremental Conductance

Figure 5.19 voltage and current output waveform

Figure 5.19 shows the voltage and current waveforms for various PV sources at varied ranges. In this the measurements for all PV sources are slightly different for that, PV1=1000w/m², PV2=500 w/m² and for PV3=1000 w/m². Here PV1 and PV3 are equal but PV2 is different for both voltage and current waveform of incremental conductance.

Voltage Hold P&O

Figure 5.20 voltage and current output waveform

Figure 5.20 represents the voltage and current waveforms for variant PV sources at different ranges. In this the levels for all PV sources are quite different for that, PV1=1000w/m², PV2=500w/m² and for PV3=500w/m². Here PV2 and PV3 are equal but PV1 is disparate for voltage and current waveforms of voltage hold P&O.

Table 5.2 Comparison of Different MPPT Techniques

The above table briefly describes the various types of MPPT techniques like voltage hold p&o, incremental conductance, modified p&o and irradiance (w/m²) for all PV sources and both voltage &current functions. Here the values for all PV sources are varied and accurate values of MPPT techniques for both voltage and current functions are also described in Table 5.2.

Hardware Results

The hardware structure deals with the PV system which needs more than one solar panels to change solar energy into electric energy. The system consists of several types of equipment like photovoltaic schedule, electrical and mechanical networks. Also, the output derived from the PV system will mainly depend on solar insulating.

Figure 5.21 Hardware Implementation

Figure 5.21 shows the Hardware function also deals with the microcontroller and power MOSFET techniques. The power MOSFET of the third generation has features of quick switching, effective device model and low-cost performance. The purpose of the driver circuit is to isolate negative current to the microcontroller and to develop a stable voltage source and this voltage is linked to the isolator for the detachment process.

When the given voltage is IR2110 IC and then the delivered voltage will have a maximum voltage that can be enough to drive the MOSFET. Here ATMEGA 8 microcontroller is needed for introducing switching pulses to the multilevel inverter. This will not produce any typical form voltage on the inverter side although it will neglect the typical form voltage and also need to neglect the capacitor voltage. The appearance of the microcontroller is an entirely stable process, great performance and leading architecture.

Switching pulses

The below figures represents pulse performance of various switches for varied levels at time =19.9ms, frequency = 50.31 Hz and voltage level = 2.38 V. When the time and frequency varied there may be variation in the switching pulses. Due to the time of variation in the switching pulses, there may be changes in the derived output voltage waveforms.

• switch S1

(b) switch S2

( c) switch S3

Figure 5.22  Pulse performance for switch S1, S2 & S3

Figure 5.22  represents the various pulse performance of switch S1, S2& S3 at time= 19.9ms, frequency=50.31 Hz and voltage =2.38V. The switch S2 quietly differs from S1. The variation of switch S3 by pulse performance at regular intervals. Here switch S3 will be directly opposite to switch S2.

Figure 5.23 Pulse performance for switch S4&S7

Here figure 5.23 Represents pulse performance for switch variation of both S4&S7 because the variation of a switch for S4&S7 is same.

Figure 5.24 Pulse performance for switch S5&S6

Like that in figure 5.24 The pulse performance for variation of switches S5&S7. Here the variation of switching S5&S7 is same.

Figure 5.25 DC link voltage waveform

Figure 5.25 shows the waveform of DC-link voltage the waveforms can occur at regular interval time constant. This waveforms clearly explains about the voltage levels of the DC link.

Figure 5.26 Output voltage waveform of seven-level MLDCLI

Figure 5.26 explains the derived output voltage levels of multi-level DC link inverter. Here the output voltage will be delivered at the exact time gap and the range of output voltage will be explained in the waveform.