Centre for Development of Advanced Computing(CDAC) Thiruvananthapuram Grid tied / Stand alone Solar inverters Technology perspective 1
Organisation of the Presentation Activities of Power Electronics Group - CDAC-Thiruvananthapuram National Mission on Power Electronics Technology Some of the development projects showcasing the capability of CDAC Development activities related to Solar Photo Voltaic Systems and other renewable sources Concluding Remarks 2
Centre for Development of Advanced Computing (CDAC) CDAC is a Scientific Society of the Department of Information Technology, Ministry of Communication & Information Technology, Government of India. CDAC Thiruvananthapuram has the following Development Groups. Power Electronics Group Broadcast & Communications Group Hardware Design Group Control and Instrumentation Group Strategic Electronics Group www.cdactvm.in 3
CDAC- Power Electronics Group -Focus Area- Power Quality Improvement Electric traction and Automotive electronics Integrated power modules and packaging techniques Distributed power generation/ Renewable energy and Micro generator control Modelling/Simulation packages New topologies for Converter/inverter applications 4
NaMPET National Mission on Power Electronics Technology A national mission programme launched in November 2004 by the Department of Information Technology (DIT) under Ministry of Communications & Information Technology, Government of India. Vision: To provide the country with capability to become a dominant player in Power Electronics Technology at the international level. Nodal Agency: C-DAC, Thiruvananthapuram Participating agencies Academic Institutes( IISc, IITs, NITs and premier technical institutes like BESU) Manufacturing Industries- both private and public sector User Industries like railways 5
Indian Railways Indian Air force NMRL Electrohms CatterPillar Pvt. Ltd. Emerson Network Power (India) Ltd. Numeric Power Systems Hykon Power Electronics (P) Ltd Amara Raja Power Systems HBL Power Systems NaMPET Industry Partners Industrial Controls and Drives Ltd Keltron Kerala Automobiles Ltd Megatech Power Equipments (P) Ltd. Power-one MicroSystems (P) Ltd Veeral Controls Techser Power Solutions Ltd. Integrated Electric Co. Bangalore Power Line Kolkata 6
Development Projects involving Grid Connected Inverters Power Quality Solutions STATCOM Active Filter (Up to 500kVA single unit) (Up to 500kVA single unit) UPQC (250 kw) Power Electronics for Renewable Energy Conversion 250kW Intelligent Power Controller for Wind Electric Generator 25 kw grid interactive Solar PV System Technology for Micro grids 7
STATCOM- STATic COMpensator Grid V ag L V ai I lc I lb I la Load V bg V cg I ia I ib I ic V bi V ci IGBT Voltage Source Inverter Capacitor Bank Shunt compensator synthesized with power electronic devices is called STATCOM or Static VAR Compensator 8
300 kvar STATCOM - For Highly Fluctuating Industrial Load - Grid voltage and Grid Current before compensation Digital Controller developed by CDAC STATCOM developed by CDAC Grid voltage and Grid Current after compensation 9
Deployment of 750 kva Active Filter for Compensation of Current Harmonics 11kV Incomer * Through this project CDAC has developed and validated operation of 3-Level Inverters Auxiliary Load Fluctuating loads like lifts, magnetic separators, drives etc. 4 MW Induction Furnace 250 KVA, 2 Level STATCOM 500 KVA, 3 Level STATCOM 10
Deployment of 750 kva Active Filter Compensated Grid Current 1) Grid current: 2 A 5 ms 2) Load current: 2 A 5 ms High power inverter stack developed by CDAC (Interconnections are with sandwich busplates) Load Current 11
Unified Power Quality Controller GRID LOAD UPQC mitigates voltage swells and sags UPQC compensates reactive power or harmonic currents drawn by the load Series Active Filter V dc Ls Shunt Active Filter 12
4-Wire STATCOMs I lc Grid I lb Load I la V ag V bg V cg I ia I ib I ic I in Compensates Reactive currents Harmonic Currents Unbalance Currents & Neutral Currents L V ai V bi V ci IGBT Voltage Source Inverter-4 leg Capacitor Bank 13
4-Wire STATCOMs for IT Parks CONVERTER STACK 500 kva, 4-Wire STATCOM This system is installed at TECHNOPARK Trivandrum It can be used in IT parks where the computer loads are single phase and non linear with large triplen harmonic currents in the neutral 14
Intelligent Power Controller for Wind Electric Generators (WEG) Machine side Inverter Grid side Inverter WEG GRID Digital Controller WEG Operates at Maximum Power Point (Induction generator is driven in variable speed) Power generation with lower wind speed Power export at UPF(without PF compensating capacitors) and minimum THD in grid current Each Inverter is rated for 250 kw and are IGBT based The system was deployed and the technology was validated with a 250 kw VESTAS WEG which uses an induction generator for power conversion. 15
Intelligent Power Controller for WEG 250 kw proto unit Digital Controller 16
Solar Energy Conversion Solar Thermal Technology for harnessing solar energy for thermal energy Solar Photo Voltaic(SPV) - Photovoltaic devices use semiconductor materials that directly generate electric power when exposed to light Cell Array Module Made of crystalline silicon (mono crystalline/ multi crystalline/ Amorphous) 17
Schemes for Solar PV Energy Conversion Solar PV Array Inverter Filter To load Storage Stand alone scheme 18
Schemes for Solar PV Energy Conversion Inverter Filter Grid Solar PV Array Storage Grid Connected scheme Optional Both the above designs should consider Overall conversion efficiency Maximum Power Point Tracking(MPPT) Cost and size of converters System reliability Protections Modularity, Servicability and repeatability 19
Technology for Micro-grid Solar PV systems can be used in conjunction with other energy technologies to provide an integrated, flexible system for power generation typically for remote locations without grid availability. These systems are referred to as hybrid systems, which can form micro grids. Common configurations of hybrid systems could include solar PV array, wind generator, bio-mass/diesel generator set which would allow generation in all weather conditions. CDAC, through NaMPET, with technical collaboration with IIT Kanpur has undertaken R&D project for developing technology for Microgrid. System developed for Moushuni Island with support of WBREDA. 20
Technology for Micro grids BIO-MASS BIM Basic Power Electronics Interface Module Y MICRO- GRID BIM WIND GENERATOR BIM SOLAR PHOTOVOLTAIC ARRAY BIM Y Y Y CONSUMER LOADS BATTERY BANK BIM * All sources interfaced to common AC bus 21
Power Converter Module The power converter module Basic Interface Module (BIM) can work with both AC and DC sources.(modular, serviceable) Individual Modules are rated for 10 kw. 3 modules are connected in parallel makes a 30kW unit. SOURCE CONVERTER Basic Interface Module (BIM) INVERTER LOAD GATE DRIVER INTERFACE CIRCUITS 22
Salient Features Modular Power Electronic Hardware DSP & FPGA Based Control Hardware Optimum Power Extraction from Solar with MPPT(Maximum Power Point Tracking) Optimum Power Extraction from WEG Parallel Operation of Inverters Synchronized Voltage reference from a Central controller Current sharing between parallel inverters 23
Digital Controller 24
Digital Controller Controls 6 independent inverters(36 PWMs) DSP-FPGA architecture CAN communication link Fast ADCs I/O ports, LED ports HMI interface Digital Controller 25
Grid Interactive Solar Photo Voltaic System Technology developed Inverter for SPV system Control algorithm for Maximum Power Point Tracking from SPV Control Algorithm for Power export at UPF and minimum THD Protection Schemes Salient Features of the system Modular Power Electronic Hardware DSP & FPGA Based Control Hardware MPPT controller Grid connected front-end inverter for power exchange Display and user Interface Power export at UPF Anti-islanding protection All the sub modules associated with the inverter (power and control) are indigenously developed The above system is commissioned at roof top of WBREDA office building, Salt Lake, Kolkata System is operational for last 5 months. Exporting around 40 units per day 26
Idc Control Block Schematic 3Ф Voltage Source Inverter Ia A SPV Vdc Ib Ic Va Vb Vc B C Vdc Idc Va Vb Vc Ia Ib Ic Vdc Idc Va Vb Vc Va Vb Vc Ia Ib Ic MPPT Algorithm 3-2 Phase Transformation Unit Vector Generation Iactive* Iactive Ireactive Cosθ Sinθ Gate Driver + - - + Ireactive* PWM1 PWM6 Va Vb Vc Vdc Current Controller & Reference Voltage Calculator Va * Vb * Vc * Space Vector Modulator PWM1 PWM6 27 PWM1 PWM6
Grid Interactive Solar Photo Voltaic System Solar Photovoltaic Array Utility Grid Power Electronic Interface Module Y Voltage and Current waveforms at various power levels Transformer 28
Grid Interactive Solar Photo Voltaic System 30kW Panel Digital Controller The digital controller is built with DSP and FPGA This controller can control six numbers of 3 phase inverters 32 Analog channels for sensing various signals Inverter modules are easily replaceable Sandwich bus plate architecture Integrated gate driver circuit and cooling arrangements Each inverter module is rated for 10kVA with DC bus rating of 400V Inverter Module 29
Specification of the Grid Interactive System Rated Power 30kW Grid Voltage Solar PV Array Voltage Grid Frequency Operating Power factor Grid Current THD Power Converter Cooling Panel 415(+10%/-15%), 3 Phase 400V max, 320 Nominal 50Hz 5% Unity above 50% Load <5% when source THD is <2% IGBT based Forced Air Cooling Suitable for Indoor deployment Efficiency Better than 90% above 50% of the load 30
Standards for Grid Interactive Solar PV Systems IEEE-928 - IEEE Recommended Criteria for Terrestrial Photovoltaic Power Systems IEEE 929-2000 - IEEE Recommended Practice for Utility Interface of Photovoltaic (PV) Systems IEEE 1547-2003 - IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems IEEE 519 - IEEE Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems IS 9000 Basic Environmental testing Procedures for Electronic and Electrical Systems The above standards are mostly related to construction, test procedures, testing methodology, protection guidelines and grid connection procedures of solar PV inverter There are different standards in relation to the SPV array 31
Solar Power Plants with MW Rating The system is realised by connecting inverters in parallel Individual inverter rating is 100kW The co-ordination of the inverters is achieved with data exchange between controllers of individual inverters through CAN communication link System features Operation sequence and protection schemes as per the relevant standards Auto turn off and auto start Active inverters selected optimally according to solar power availability Remote data access Minimum power consumption by auxiliary circuits 32
Conclusions CDAC has expertise in Design of single phase inverters, 3 phase inverters and multi level inverters up to 500kVA ratings, using IGBTs, IPMs etc. Design and realisation of digital hardware for control of inverters for various applications CDAC has developed Grid Interactive Solar PV System with Indigenous technology Technology for Micro grids using various renewable energy sources (AC and DC) and storage systems CDAC can associate with prospective industries for commercialisation of the technology for renewable energy sources-solar in particular 33
Thank You 34