Design and implementation of constant voltage constant frequency PWM inverter for solar applications
DC power supply provides a constant value steady flow of power, regardless of time. DC power is unidirectional, while AC is considered to be bidirectional as well as continuously varying with time, having positive and negative portions. This project is to convert a DC voltage signal to a
2025-06-28 16:31:42 - Adil Khan
Design and implementation of constant voltage constant frequency PWM inverter for solar applications
Project Area of Specialization Electrical/Electronic EngineeringProject SummaryDC power supply provides a constant value steady flow of power, regardless of time. DC
power is unidirectional, while AC is considered to be bidirectional as well as continuously
varying with time, having positive and negative portions. This project is to convert a DC
voltage signal to an AC voltage signal having pure sinusoidal waveform by implementing
constant voltage constant frequency PWM based closed-loop inverter.
We will design hardware to get pure sinusoidal signals by designing a closed-loop
controller. First, we have to decrease the magnitude level of signals by using voltage and
current monitoring board so we can use such low signals as input to DSP (Digital Signal
Processing) board. We generate the required PWM signal by controlling the sampling rate of
the sampler corresponding to the frequency of the reference signal.
This whole process is a closed-loop controlled process in which we compare the
generated PWM with a reference signal and feedback into the system to minimize the error.
We will use repetitive control techniques (FORC or ARC) or PR control technique.
Moreover, we have to design a setup to generate DC signal by using solar energy, this DC
signal will be used as input for the inverter that gives six variable signals (three voltage
signals and three current signals).
Some work has already done in this domain to design such controller but the main
contribution from our side is to design and make constant voltage constant frequency PWM
inverter by using DSP board and designed a new controller to get desire output sinusoidal
the signal having zero THD (total harmonic distortion) factor.
- To create a more efficient DC to AC power converter producing pure sinusoidal voltage signal having a constant frequency.
- To create a sine wave of almost 0% THD.
Following steps will be implemented for the completion of the project:
-
First, we will explore different design strategies to find the best one to create our closed-loop model.
-
We will then design the complete setup including PCBs, invertors, DSP etc. and run simulations to make sure that our required output is being achieved.
-
Then we will explore different hardware alternatives to pick the most reliable and capable structure for our project which will be cost-effective and durable.
-
Finally, we will assemble all the pieces together and run tests along the way to make sure every component is working properly and according to our needs.
-
Finalizing the project will include troubleshooting and bug removing to make the system robust and finer.
-
Due to this, we can connect the load of houses to renewable sources.
-
Significantly reduced running costs compared to other systems.
-
On a small scale, small solar plants can be interconnected to utility grids to maintain healthy power consumption and distribution.
-
In remote areas, power supplying will be easy as small DC plants will be settled near them.
-
In facilities that require instantaneous energy, such as hospitals and airports, in backup system power is drawn from batteries this converter can be used to provide power until backup generators come online.
-
This can also be employed in wind turbines as turbine speed usually varies causing changes in voltage, frequency and sometimes in magnitude. In this case, the inverter will keep the voltage and frequency constant as required.
After all the milestones have been accomplished, we will have a closed-loop variable DC to pure sinusoidal AC source having constant voltage and constant frequency. The finalized product will contain the following items:
-
Buck/Boost converter connected to a variable DC solar plate providing a constant voltage DC source.
-
Inverter to convert DC power to AC power controlled by a Digital signal processor connected in closed-loop with it.
-
Signal converters for the compatibility of the inverter with the Digital Signal Processor at both input and output side.
-
At input, we will be creating six signals from our 3-phase supply to be fed to the DSP.
-
At the output, we will be gaining a PWM which will be responsible for controlling the inverter.
-
Highly efficient model-based program for the operation of DSP.
| Item Name | Type | No. of Units | Per Unit Cost (in Rs) | Total (in Rs) |
|---|---|---|---|---|
| Total in (Rs) | 79050 | |||
| Solar panel | Equipment | 1 | 7000 | 7000 |
| Digital Signal Processor | Equipment | 1 | 40000 | 40000 |
| Resistor | Equipment | 50 | 20 | 1000 |
| BJTs | Equipment | 50 | 5 | 250 |
| ICs | Equipment | 50 | 100 | 5000 |
| Jumpers | Equipment | 100 | 5 | 500 |
| Diodes | Equipment | 50 | 2 | 100 |
| PCB | Equipment | 10 | 300 | 3000 |
| Capacitors | Equipment | 50 | 12 | 600 |
| Inductors | Equipment | 30 | 30 | 900 |
| Solder wire | Miscellaneous | 3 | 400 | 1200 |
| Transformer | Equipment | 6 | 300 | 1800 |
| Travel Charges | Miscellaneous | 8 | 150 | 1200 |
| LEDs | Equipment | 10 | 4 | 40 |
| CTs | Equipment | 6 | 300 | 1800 |
| Battery | Equipment | 1 | 8000 | 8000 |
| Printing cost | Miscellaneous | 500 | 5 | 2500 |
| Soldering paste | Miscellaneous | 2 | 80 | 160 |
| Casing/Protection | Miscellaneous | 4 | 1000 | 4000 |