Informatics Publishing Limited

K. J. Shruthi ¹, P. Giridhar Kini ², C. Viswanatha ³

Affiliations
1 Instrumentation Division, Central Power Research Institute, IN
2 Department of Electrical and Electronics Engineering, Manipal Institute of Technology, IN
3 Diagnostics Cables and Capacitors Division, Central Power Research Institute, IN

Abstract

Field solar radiation measurement is very essential to estimate the conversion efficiency of the solar photovoltaic (PV) system. Pyranometers, instrument used for solar radiation measurement are very expensive and require regular calibration and increasing maintenance cost. This paper provides an alternative low cost solution to estimate the solar radiation received on field. The paper addresses the design and development of MSP430G2553 microcontroller based data logger for measurement of the solar panel voltage and current output. The design is based on maximum power point tracking technique using 16-bit microcontroller to measure, analyse and compute the instantaneous maximum power of solar PV panel. The data is communicated through RS485 onto storage device for future analysis. The experimental analysis is carried out in Bengaluru co-ordinates. The estimated solar radiation is compared with recordings from a calibrated pyranometer. The loggers required very low power requirement and can be powered by the parent panel on which they are mounted thus avoiding requirement of grid. This feature makes it ideal for use in rural side field PV analysis. The developed SPV logger gives accurate measurement of solar PV output and aide in estimation of incoming solar irradiance.

Keywords

Solar Photovoltaic (SPV), Irradiation Calculation, Pyranometer, Optimized Power Measurement, Microcontroller.

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Vani Vijay ¹, C. Viswanatha ², P. Giridhar Kini ³

Affiliations
1 Senior Research Fellow, Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore- 560080, IN
2 EEE Department, Manipal Institute of Technology, Manipal - 576104, IN
3 Diagnostics Cables and Capacitors Division, Central Power Research Institute, Bangalore - 560080, IN

Abstract

Using load emulation, the performance of source side converters can be easily evaluated and improved without the need for actual load. Due to the increase in use of power electronic converters and SMPS based systems, the harmonic levels in load side has increased considerably. Hence emulation of variable THD load is very important in analysing the performance of source side converters and ensure the performance efficiency and power quality under such loads. Here a novel method of obtaining variable load using PWM control explained. The PWM is controlled in a rainbow sinusoidal fashion to obtain clipped waveform across a resistor so that harmonics is introduced in the Load. The power factor can also be varied in the system by paralleling it with leading and lagging converter circuits. The working principle, modelling and simulation are presented along with the results. Proposed technique provides accurate modulation of load THD and effect of harmonics loads on sources converter are also analysed using this.

Keywords

Load Emulation, harmonic loads, current clipping

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Vani Vijay ¹, P. Giridhar Kini ², R. Sudhir Kumar ¹

Affiliations
1 Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore- 560080, IN
2 EEE department, Manipal Institute of Technology, Manipal -576104, IN

Abstract

Pulse Width Modulation (PWM) control of MOSFET based converters is used in almost all electrical application for accurate and efficient operation, like in motor drives, power supply units, power conditioners etc. The algorithm of PWM control in such system is the most important factor determining the operational features which can be implemented using microprocessors, micro controller, digital signal processors or higher end technologies. Here a detailed study of micro controller programming is done for PWM control of MOSFET based converters. The method of configuring the controller for PWM generation and programming steps are explained in detail with an example of PIC16F877A micro controller. Hardware implementation is done and program variation for different operating characteristics are observed. Micro controller programming is easiest, accurate and cost effective method for PWM control of converter. The program is flexible and higher end micro controllers can be used for complex control technique.

Keywords

Programming, micro controller, PWM control

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Vani Vijay ¹, C. Viswanatha ², P. Giridhar Kini ³, R. Sudhir Kumar ⁴

Affiliations
1 Senior Research Fellow, Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore - 560080, IN
2 Electrical and Electronics Engineering department, Manipal Institute of Technology, Manipal - 576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore - 560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore - 560080, IN

Abstract

Solar Photo Voltaic (SPV) sources are widely used in present scenario of energy crisis for various applications including grid connected PV plants and grid isolated standalone applications. The performance of solar PV system is highly dependent upon the operating conditions of source and loads especially in standalone applications. The effect on various types of loads on standalone system can be easily analyzed at design stage and testing stage by using load emulation technique, where a virtual load is used to replace actual load, giving more flexibility and accuracy to loading conditions. Here a novel load emulator model is presented which can provide accurate variation in load power factor and THD compared to existing models. The converter decouples the current in to in phase and out of phase components and the in phase component can be regenerated. The model is simulated using MATLABTM simulation and the results are validated by comparing with experimental results obtained by loading SPV inverter with actual load. Hence the proposed load emulator is very useful in design and development of application specific solar PV systems and also for performance analysis of such systems based on various standards.

Keywords

Solar PV inverters, non-linear loads, low pf loads

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Vani Vijay ¹, P. Giridhar Kini ², C. Viswanatha ³, K. Pradeep ⁴

Affiliations
1 Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore- 560080, IN
2 E&E Department, Manipal Institute of Technology, Manipal - 576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore - 560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore - 560080, IN

Abstract

Efficiency of power electronics devices are highly dependent on temperature. Hence temperature compensation and heat sink design are very important factors in maintaining the performance quality of power electronic converters. Thus the ambient temperature at which the device is operating also effects the performance since the heat removal by heat sinks or cooling fans is affected by the ambient temperature. Here a detailed analysis of the dependency of losses in power electronic switches on the junction temperature and in turn ambient temperature is presented. A theoretical Analysis of conduction losses and effect of ambient temperature on it is presented along with a set of experimental results by analyzing the performance of a 850W Solar PV inverter at various ambient temperatures. The results are satisfactorily explaining the effect of ambient temperature on converter efficiency.

Keywords

Solar PV inverters, conduction Losses, heat sink, ambient temperature

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Vani Vijay ¹, P. Giridhar Kini ², C. Viswanatha ³, S. Jothi Basu ⁴

Affiliations
1 Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore - 560080, IN
2 E&E Department, Manipal Institute of Technology, Manipal - 576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore - 560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore - 560080, IN

Abstract

AC-DC converters are very commonly used in many power electronics applications including controllable sources and machine drives. Rectifier circuit results in harmonic distortions in AC side and requires large capacitive filter for reducing DC ripples on the output side. Use of active power factor technique can be utilized for solving this issue resulting in better performance of the converter. It basically consists of boost converter with high frequency switching following the rectifier controlled using a suitable microcontroller. This paper presents the detailed design and operation of Active power factor corrected rectifier which operates with reduced THD and improved power factor there by reducing losses in power flow and utility. Simulation of the designed converter and comparison with conventional topology is also discussed.

Keywords

Rectifier; active power factor correction, capacitive filtering

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K. J. Shruthi ¹, P. Giridhar Kini ², C. Viswanatha ³, Rajashekar P. Mandi ⁴

Affiliations
1 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore- 560080, IN
2 E&E department, Manipal Institute of Technology, Manipal 576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore 560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore -560080, IN

Abstract

Renewable energies are the most sought after alternatives for electric energy generation. The improvement in semiconductor and power electronics technology has led to precise operation of system at maximum power point, thus increasing the efficiency of the PV system. Many maximum power point tracking (MPPT) algorithms have been developed in recent times which provide maximum power tracking under varying conditions. Among the existing algorithms, perturb and observe (P & O) is the most explored technique. In this paper a comparison between the conventional P & O and improved P & O method is brought about. A MATLAB simulink based simulation study of PV module/ array is carried out and both the MPPT algorithms are explored for z-source inverter in photovoltaic system.

Keywords

Solar Photovoltaic (SPV) system, Modeling of PV arrays, Z-source inverter (ZSI), Perturb and Observe (P & O), Improved perturb and observe (IP & O), Maximum power point tracking (MPPT)

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Vani Vijay ¹, P. Giridhar Kini ², C. Viswanatha ³, S. Jothi Basu ⁴

Affiliations
1 Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore-560080, IN
2 E & E Department, Manipal Institute of Technology, Manipal-576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore-560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore-560080, IN

Abstract

Inverter and power conditioning circuit is the most important part of solar PV system which is responsible for providing the AC output as per the requirement of the application. The presence of AC harmonics and DC ripples in the inverter is still an unavoidable drawback, even though it has reduced to a great extent in past two decades. This paper presents a detailed study of distortions in the AC and DC sides of commercial standalone single phase Solar PV inverter and the effect of the same in the application. The harmonic content is evaluated by loading the inverter using electronic loading. The reduction in distortions in the AC and DC sides by utilization of a high impedance network on the DC side of the inverter is also evaluated by simulation. A comparative study of harmonics and DC ripples in the inverter under test and the simulated impedance source inverter is also presented.

Keywords

Harmonics, Stand alone Solar PV inverters, DC ripples, Impedance network

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