Robust Control of Grid Connected Inverter

Project Title

Robust Control of Grid Connected Inverter

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

The grid tied converters are used to inject power from renewable energy sources into a utility grid. There exists number of challenges in order to achieve this such as; renewable sources are intermittent in nature thus result in variation in source power, power injected must be synchronized in form of voltage, frequency and phase with that of grid parameters which have variations as well (voltage amplitude and frequency variations due to variable connected loads), injected power must satisfy quality parameters , furthermore injected power must be controlled in terms of input source/s and inverter ratings.

All these conditions result in complex power processing and it cannot be achieved without feedback. The resultant system is time variant and nonlinear requiring sound control law to achieve desirable outcome and stable system.

In this project model predictive control law will be applied to inject quality power within a national grid. The design will be verified first through simulations and then on a prototype hardware

Project Objectives

The objectives of the project are to apply model predictive controller on a grid inverter for injecting quality power in the national grid. and to affectively use renewable energy units and to promote clean energy. Following are the project objectives.

• To design digital predictive controller for grid tie converters.
• To design converter which will effectively utilize renewable generation units.
• To design low pass LCL filter for the inverter.
• To develop protected coupling unit for inverter and grid integration.
• To promote utilization of neat and clean energy.

Project Implementation Method

Based on our objectives and by viewing the literature a system will be designed. The comprehensive mathematical model of the inverter system will be derived. This model will be used to design control law based on model predictive theory. System stability and performance will be evaluated by using simulations. Finally proposed design will be verified on prototype.

 A document will be compiled in the form of thesis that will be comprised of proposed techniques, equation formulation, simulation results and prototype results.

Project submissions would be:

• Project report covering all details of the design.
• Simulation files with detailed description for using simulation models and evaluating performance.
• Hardware prototype including:
  • H-Bridge inverter
  • FPGA code
  • Design specifications, including connection diagrams

Benefits of the Project

In past, mostly converters used as a backup system for AC power source like UPS (Uninterruptible Power Supply). They do not require any synchronization like frequency and phase. Rather they require controlled voltage or controlled current. Now a day’s converters are not only used for backup power but also, they are used to supply power to the grid (Grid Connected Inverters).

Grid connected photovoltaic systems guarantee a home always has access to power, even if the solar energy fails or is insufficient. The system's inverter connects to a battery bank that can store energy to be used in a power failure. An advantage of grid connected systems is that they are not dependent on the sun shining. Off grid photovoltaic energy is only intermittent but grid connected systems ensure that any additional electricity needed is automatically delivered by the grid.

Technical Details of Final Deliverable

1. Inverter: A 1KW grid tie inverter, consisting of power electronic full bridge inverter with fault protection gate drives and low pass LCL filter.
2. FPGA Code: The digital predictive control law will be implemented on FPGA board (Spartan 3 3S400) the software Verilog based code will be included.
3. Power Coupling Unit: Power coupling unit is required to connect inverter with that of national grid. It will also be included within deliverable items.
4. Report: Finally, a compressive report detailing design, software usage description, and analyzing system using simulations will be included.

Final Deliverable of the Project Hardware SystemCore Industry Energy Other IndustriesCore Technology Clean TechOther TechnologiesSustainable Development Goals Affordable and Clean Energy, Climate ActionRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	80000
FPGA board	Equipment	1	15000	15000
Bidirectional meter	Equipment	1	15000	15000
Transformers	Equipment	26	450	11700
Rectifiers	Equipment	20	50	1000
Capacitors	Equipment	10	50	500
Capacitors	Equipment	10	200	2000
Capacitors	Equipment	50	4	200
Voltage Regulator IC	Equipment	20	40	800
heat sink for voltage regulator	Equipment	20	20	400
Connectors	Equipment	60	10	600
Connectors	Equipment	60	10	600
Connectors	Equipment	60	20	1200
Switch	Equipment	20	10	200
PCB	Equipment	10	700	7000
Power IGBT	Equipment	10	200	2000
Driver for IGBT	Equipment	10	150	1500
heat sink for IGBT	Equipment	10	50	500
Base for driver	Equipment	10	10	100
Screws	Equipment	100	5	500
Screws	Equipment	50	20	1000
Resistors	Equipment	10	20	200
Resistors	Equipment	10	5	50
capacitor	Equipment	10	20	200
Inductor	Equipment	2	1000	2000
Capacitor	Equipment	2	500	1000
Feric Chloride	Equipment	10	150	1500
Solder wire	Equipment	1	800	800
Wire connectors	Equipment	490	5	2450
PCB Printing Paper	Miscellaneous	100	20	2000
PCB Printing	Miscellaneous	100	20	2000
Permanent Marker	Miscellaneous	10	50	500
stationary	Miscellaneous	1	1000	1000
Project Representation tools	Miscellaneous	1	2000	2000
overheads	Miscellaneous	1	2500	2500