Optimized MPPT Based Pure Sine Wave Solar Inverter

In this research, an optimized MPPT based solar inverter for the purpose to reduce the energy crisis will be designed. In the proposed inverter, the particle swarm optimization (PSO) algorithm is used for tracking the maximum power point (MPP) of PV array. ESP-32 microcontroller board is used to exe

Project Title

Optimized MPPT Based Pure Sine Wave Solar Inverter

Project Area of Specialization

Electrical/Electronic Engineering

Project Summary

In this research, an optimized MPPT based solar inverter for the purpose to reduce the energy crisis will be designed. In the proposed inverter, the particle swarm optimization (PSO) algorithm is used for tracking the maximum power point (MPP) of PV array. ESP-32 microcontroller board is used to execute the PSO algorithm and generate the pulses of specific duty cycle. These pulses are applied to Isolated DC-DC Boost converter to track the MPP and boost the PV array input voltage from 24v to 350v. The full bridge topology is used to convert the high DC voltage of isolated boost converter to AC voltage. For this purpose, SPWM unipolar inverter is designed. Output of SPWM unipolar inverter has high frequency harmonics having THD greater than 5%. The LC low pass filter is used to attenuate these high frequency harmonics and provide required sinusoidal output voltage signal.

From the beginning, power generation in the form of electricity around the world is one of the main problems. Use of renewable resources such as wind and solar energy for power generation are the best solutions. To overcome the deficiency of power generation, different organizations are investing millions and billions on different power generation projects including solar systems, dams’ constructions, and air turbines. China has the largest solar power generation system which has generated 205 GW of power in 2019 according to EA's Renewables 2020 report [1]. Solar systems work well but still cannot deliver much efficiency. The output of solar panels depends upon the temperature and the irradiance of the sun. Also, at maximum irradiance of the sun, the system cannot give maximum power without using a solar controller. MPPT is one the best technique used for in solar controllers to deliver maximum power from solar panel. It has an average efficiency more than 95%.

There are multiple Algorithms used for tracking the maximum power point of PV panel. Artificial intelligence-based algorithms are the most efficient and powerful algorithms used in normal as well as under partial shading conditions. The tracking speed of PSO algorithm is very fast under partial condition compared to hill climbing algorithms. PSO algorithm tracks the maximum power point of solar array and calculate the corresponding duty cycle for PWM signal. ESP-32 microcontroller board is used to execute the PSO algorithm and generate the pulses of specific duty cycle. These pulses are applied to Isolated DC-DC Boost converter to track the MPP and boost the PV array input voltage from 48v to 350v. 

The Full bridge inverter is used to convert output of the converter output to AC sinusoidal wave form. The PWM technique used for DC-AC conversion is unipolar sinusoidal pulse width modulation. The SPWM signal decides output signal phase, frequency and voltage amplitude by varying modulation index of reference signal. The output AC signal has same frequency as reference signal of SPWM.

Project Objectives

• Designing of DC-to-DC isolated Boost converter to convert low PV DC voltage to higher DC voltage
• Implementation of MPPT algorithm using ESP-32 microcontroller
• Applied MPPT algorithm to DC-DC isolated Boost converter which work as MPPT controller
• Designing of MPPT solar charge controller
• Designing of Unipolar SPWM signal for H-bridge inverter using Arduino UNO microcontroller board
• Designing PV inverter to convert DC to three level square wave
• Designing LC low pass filter to convert five levels square wave signal to pure sinusoidal signal
• Hardware implementation of all the circuitry to get the deliverable hardware.

Project Implementation Method

The implementation of this project will be done using the following methodology. As we explained earlier, that the main aim of this project is designing a system to get highly efficient power from solar panels and convert this power to AC sinusoidal using transformer less PV inverter. We have divided this project into following stages,

1. PSO Algorithm implementation
2. Solar charge controller designing
3. Isolated boost converter designing
4. SPWM full bridge inverter designing with output filter

PSO Algorithm implementation

To implement MPPT algorithm, ESP-32 microcontroller board is used. The PWM signal generated by ESP-32 microcontroller with specific duty cycle is given to isolated boost converter. The MPPT controller gets output of solar panel as input, varies the voltage and track the maximum power point of the array.

Solar charge controller designing

A battery will be used for backup purpose. In order to charge the battery, MPPT solar charge controller is used to charge the battery. It consists of DC - DC buck converter with PWM signal generated by MPPT algorithm. The input of the solar charge controller is PV array output and its output is connected to battery bank.

Isolated boost converter designing

This converter consists of full bridge with galvanic isolation between input and output sides. PWM signal generated by ESP-32 microcontroller board is provided to full bridge MOSFETs’ as gate signals for MPP tracking. There are multiple reasons of using Isolated boost converter as following,

• Maximum power point tracking
• Converting PV low voltage to high DC voltage
• Designing transformer-less PV inverter

SPWM full bridge inverter designing

The high DC voltage from DC-DC isolated boost converter is provided as input to full bridge inverter. It consists of four IRF740 MOSFET’s. This H-bridge inverter gives five levels square wave at output. The output of H-bridge inverter is not pure sinusoidal. To make it less harmonics signal i.e., from five levels square wave to sinusoidal waveform, high frequency harmonics should be removed. A low pass filter can perform this operation. In this research project, LC low pass filter is used to convert five levels square wave to pure sinusoidal waveform. The output of the LC low pass filter is pure sinusoidal.

Benefits of the Project

As we all know, that there are severe energy crisis in Pakistan, wo we need to search and utilize the alternate energy sources. According to IEA report 2019, as 73.91% of Pakistan has access to electricity. The federal and remote areas are farther behind of this estimated range. Renewable resources like solar system are helpful to reduce these problems.

Due to this research, an individual or an organization would become able to generate their own electrical energy. Solar systems are not much efficient without using MPPT. MPPT is used to get maximum power from solar systems. The motivation of proposed MPPT based PV inverter is to reduce this energy crisis, and provide the proposed inverter in compatible cost.

The proposed inverter is pure sine wave inverter with total harmonic distortion less than 5% which is also acceptable by IEEE. The inducive and capacitive loads can also be worked perfectly on the proposed inverter as these loads can not operate perfectly on modified sinusoidal inverter and square wave inverter.

Technical Details of Final Deliverable

The deliverable project will be is in form of hardware. The following circuits, modules and components will be presented submitted or delivered in hardware form,

• 48V solar panel
• Isolated DC – DC boost converter
• MPPT solar charge controller with DC – DC buck converter
• 48v battery for backup
• Full bridge with IRF740 MOSFETs’
• LC low pass filter for 50Hz cutoff frequency
• Software Based MPPT Algorithm

Final Deliverable of the Project

HW/SW integrated system

Core Industry

Energy

Other Industries

Education , IT , Medical

Core Technology

Artificial Intelligence(AI)

Other Technologies

Internet of Things (IoT), Others

Sustainable Development Goals

Affordable and Clean Energy

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com