Three Phase Cascaded Multilevel H-bridge Inverter for Grid connected applications
Renewable energy, often referred to as clean energy, comes from natural sources or processes that are constantly replenished. For example, sunlight or wind keep shining and blowing, even if their availability depends on time and weather. A three-phase modular cascaded H-bridge multilevel inverter fo
2025-06-28 16:29:45 - Adil Khan
Three Phase Cascaded Multilevel H-bridge Inverter for Grid connected applications
Project Area of Specialization Electrical/Electronic EngineeringProject SummaryRenewable energy, often referred to as clean energy, comes from natural sources or processes that are constantly replenished. For example, sunlight or wind keep shining and blowing, even if their availability depends on time and weather. A three-phase modular cascaded H-bridge multilevel inverter for a grid-connected photovoltaic (PV) system is our project. Main function of our project is to convert solar energy into electrical energy with the most efficient way possible. First, solar energy will be converted to electrical (DC) by PV panels. Then that DC will be converted to AC with the help of multilevel inverter. Before the conversion of DC to AC we maximize the solar energy extraction of each PV string, an individual maximum power point tracking(MPPT) control scheme is applied, which allows the independent control of each dc-link voltage. PV mismatches may introduce unbalanced power supplied to the three-phase system. To solve this issue, we use pulse width modulation. Solar panel will be connected through capacitors with PV panels to make use of single PV panel for multiple H-bridges. We will make use of solar energy to convert it from DC to AC voltage having desirable frequency and then fed it to Grid and make use of this for domestic purposes. Its maintenance is quite easy as they work well even with usual maintenance for the three-phase grid-connected PV system, PV mismatches may introduce unbalanced supplied power, resulting in unbalanced injected grid current. A pulse width modulation compensation scheme will not increase the complexity of the control system or cause extra power loss, is added to balance the grid current. When we couple the PV System with H-Bridges through capacitors, it will reduce the overall cost by reducing the MPPT circuits to lowest in the overall system. Due to noise, distortions, and frequency variations, the complexity of phase locking is increased. However, large and abrupt variations of frequency and phase of the input signal may not be properly tracked by a control loop. In three-phase system, the most extended technique used for grid synchronization is a synchronous reference frame PLL (SRF-PLL).
Project ObjectivesMain function of our project is to convert solar energy into electrical energy with the most efficient way possible. First, solar energy will be converted to electrical (DC) by PV panels. Then that DC will be converted to AC with the help of multilevel inverter. Before the conversion of DC to AC we maximize the solar energy extraction of each PV string, a control scheme, maximum power point tracking (MPPT) is applied, which allows the independent control of each dc-link voltage. PV mismatches may introduce unbalanced power supplied to the three-phase system. To solve this issue, we use pulse width modulation (PWM). Solar panel will be connected through capacitors with PV panels to make use of single PV panel for multiple H-bridges. Power Converters holds great significance in support of wide range of applications such as automotive applications, energy conversion, and industrial manufacturing. These process contain continuously growing their demand power on the way to achieve advanced manufacture rates, as well as charge lessening. The general structure of the multilevel converter generates sinusoidal voltage from various DC voltage level, it is usually obtained from capacitor voltage sources.As the number of levels m increases, the output waveform steps increases, as a result it produces a staircase wave that resembles a required waveform. By applying power electronics techniques, harmonic distortion of the output waveform reduces significantly, approximately approaching to zero as the number of levels increases further
Project Implementation MethodSolar panels used for light energy conversion in DC. H-Bridges used for DC to AC inversion. MPPT and PWM techniques are used for extraction of maximum power and removal of harmonics respectively. MPPT technique is used to extract maximum power from the PV module PWM is used all around as a framework for driving cooling contraptions with a DC power source. In principal equipment, a PWM sign is passed on by connecting with the reference and transporter signal from a comparator and which makes the posted notification in setting of the ability among two inputs. The basic reference is in sinusoidal waveform and the vehicle wave is a triangle or "saw tooth" wave which works at a repeat basically more unmistakable than the reference wave. Most important is Phase locked loop (PLL). The basic idea of the PLL system is a feedback system with a PI-regulator tracking the phase angle. Input is the three phases of the grid voltage and output from the PLL is the phase angle of one of the three phases. Estimating the phase angle of grid plays a crucial role in grid interactive inverter in order to be synchronized the inverter and the grid . Phase locked loop (PLL) method is usually used in applications of grid synchronization. The angle information obtained by the PLL ensures the amplitude, phase and frequency of the inverter the same as grid.
Benefits of the ProjectNo capacitor or diode is required for clamping purpose and output voltage is sinusoidal in nature and even for higher number of level we do not need any filter. In 3-phase system, output of three identical structure of single phase cascaded H-bridge multilevel inverter can be connected in either Delta or WYE configuration.For 3-phase 5-level cascaded H-bridge multilevel inverter , two H-bridge cells with eight switches are required. In short 12 pairs of gating signals gating signals generated will be fed to the switches. For single H-bridge cell, design of switching is low- frequency switching. The power converted from PV modules has usually less power as compared to the power rating of PV panels. This is the problem here and we will overcome it with MPPT technique to draw maximum power.H-bridges. Power Converters holds great significance in support of wide range of applications such as automotive applications, energy conversion, and industrial manufacturing. These process contain continuously growing their demand power on the way to achieve advanced manufacture rates, as well as charge lessening. It is environment friendly and economically affordable with a very low maintenance cost. The techniques we used are for high efficiency to reduce power loss.
Technical Details of Final Deliverable
Our main aim is to design an inverter which takes input from solar energy and use it in grid connected applications. MPPT technique is used to extract maximum power from the PV module. Pulse width modulation is used to compensate the harmonics and reduce the THD to the lowest level possible. No activation energy/fuel/power is required to generate power for grid connected applications.It contains series of H-bridge, commonly single phase and bridge inverter units. Major function of this inverter is to produce desired output voltage from separate DC sources like solar cells, batteries, fuel cells and ultra-capacitors.The Cascaded H Bridge (CHB) is very popular in high power AC supplies. This consists of a series H bridge of which each H Bridge has its own dc source. This DC source can be replaced by means of renewable sources such as PV system, wind system or as a fuel cell.MPPT is a technique which is used to enhance the power and increase the efficiency of system which is applying on a boost converter. An MPPT tracks the maximum power point, which is going to be different from the STC (Standard Test Conditions) rating under almost all situations. The Power Point Tracker is a high-frequency DC to DC converter. They take the DC input from the solar panels, change it to high-frequency AC, and convert it back down to a different DC voltage and current to exactly match the panels to the batteries. PV generation systems have two major problems: the conversion efficiency of electric power generation is very low (9-16%), especially under low irradiation conditions and the amount of electric power generated by solar arrays changes continuously with weather conditions.
Mathematical Equations for MPPT: Perturbation and Observation techniques is studied. The output current I and output voltage V of solar cell is given by (1), (2) and (3)
I=Iph-Id-Vd/Rsh (1)
V=Vd-RsI (2)
Id=Io{exp(qVd/nKT)-1} (3)
Here Iph is the photocurrent (in amperes), Io is the reverse saturation current (in amperes), Id is the average current through diode (in amperes), n is the diode factor, q is the electron charge
(in coulombs), k is Boltzmann’s constant (in joules per Kelvin), and T is the solar arrays panel temperature (in Kelvin). Rs is the intrinsic series resistance of the solar cell
PWM is a technique that is used to reduce the total harmonic distortion. Total harmonic distortion in a load current. Pulse Width Modulation (PWM) is the most effective means to achieve constant voltage battery charging by switching the solar system controller's power devices. When in PWM regulation, the current from the solar array tapers according to the battery's condition and recharging needs. , PLL methods are also being used as a new field to provide synchronization in grid interactive inverters. In addition, these methods should have a good response to various disturbing effects such as imbalances, harmonics, frequency changes, and phase jump in the grid voltages.
Final Deliverable of the Project Hardware SystemCore Industry Energy Other IndustriesCore Technology OthersOther TechnologiesSustainable Development Goals Affordable and Clean EnergyRequired Resources| Item Name | Type | No. of Units | Per Unit Cost (in Rs) | Total (in Rs) |
|---|---|---|---|---|
| Total in (Rs) | 64840 | |||
| IRF740 | Equipment | 30 | 70 | 2100 |
| IR2110 | Equipment | 15 | 300 | 4500 |
| Heat sink | Equipment | 30 | 30 | 900 |
| Resistors/Diodes/capacitors | Equipment | 30 | 500 | 15000 |
| PCB sheets | Equipment | 8 | 1400 | 11200 |
| Batteries | Equipment | 6 | 1450 | 8700 |
| Mppt controller | Equipment | 3 | 3340 | 10020 |
| Audrino | Equipment | 3 | 1840 | 5520 |
| Transformer | Equipment | 5 | 1260 | 6300 |
| Printing | Miscellaneous | 3 | 200 | 600 |