Performance of medium voltage dc-bus pv system architecture utilizing high-gain dc–dc converter
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The document discusses a medium-voltage DC-bus photovoltaic (PV) system architecture that utilizes high-gain DC-DC converters to enhance efficiency by allowing each PV array to operate at its maximum power point. It compares conventional inverter configurations with a proposed system featuring three PV arrays, a step-up transformer, and two power conversion stages. Advantages include reduced current ripple and increased power ratings, making it suitable for photovoltaic applications.
Performance of medium voltage dc-bus pv system architecture utilizing high-gain dc–dc converter
- 1. Do Your Projects With Domain Experts… Copyright © 2015 LeMeniz Infotech. All rights reserved Page number 1 LeMeniz Infotech 36, 100 Feet Road, Natesan Nagar, Near Indira Gandhi Statue, Pondicherry-605 005. Call: 0413-4205444, +91 9566355386, 99625 88976. Web : www.lemenizinfotech.com / www.ieeemaster.com Mail : projects@lemenizinfotech.com Performance of Medium-Voltage DC-Bus PV System Architecture Utilizing High-Gain DC–DC Converter Abstract Introduction: Currently, large-scale PV systems interface to the grid via central or multistring inverter configurations. Nevertheless, mismatch power losses from the limitation of single maximum power point tracking (MPPT), particularly under partial shading conditions, and the power losses from the reverse-current blocking diodes degrade the efficiency of this PV configuration. The multistring configuration introduces dc–dc converters between the PV array and the inverter. Most commercial multistring PV inverters place dc–dc converters inside the same casing, and their power range is between 5 and 20 kW. The additional power converter allows each PV array to be operated at its maximum power point (MPP), which greatly increases the overall MPPT efficiency. A higher MPPT efficiency will outweigh the increased cost of the additional power conversion
- 2. Do Your Projects With Domain Experts… Copyright © 2015 LeMeniz Infotech. All rights reserved Page number 2 LeMeniz Infotech 36, 100 Feet Road, Natesan Nagar, Near Indira Gandhi Statue, Pondicherry-605 005. Call: 0413-4205444, +91 9566355386, 99625 88976. Web : www.lemenizinfotech.com / www.ieeemaster.com Mail : projects@lemenizinfotech.com stage. A central PV inverter configuration for direct medium- voltage connection has been commercialized. Although the efficiency is increased and overall costs are lowered by achieving MV grid integration with only one step-up transformer, the inverter includes an MV-level transformer with a high turns ratio. Existing system: Conventional step-up converters, such as the boost converter and flyback converter, cannot achieve a high step-up conversion with high efficiency because of the resistances of elements or leakage inductance; also, the voltage stresses are large. A boost converter (step-up converter) is a DC-to-DC power converter with an output voltage greater than its input voltage. It is a class of switched-mode power supply (SMPS) containing at least two semiconductors (a diode and a transistor) and at least one energy storage element, a capacitor, inductor, or the two in combination. Filters made of capacitors (sometimes in combination with inductors) are normally added to the output of the converter to reduce output voltage ripple. Proposed system:
- 3. Do Your Projects With Domain Experts… Copyright © 2015 LeMeniz Infotech. All rights reserved Page number 3 LeMeniz Infotech 36, 100 Feet Road, Natesan Nagar, Near Indira Gandhi Statue, Pondicherry-605 005. Call: 0413-4205444, +91 9566355386, 99625 88976. Web : www.lemenizinfotech.com / www.ieeemaster.com Mail : projects@lemenizinfotech.com The PV system architecture contains three identical PV arrays, one step-up transformer and two power conversion stages: a dc–dc stage using SSIB converters and a dc–ac stage using a voltage source converter (VSC). The PV array contains several parallel connected PV strings consisting of many PV panels connected in series. A conventional inverter consisting of a VSC with sinusoidal pulse width modulation (PWM) and a delta-wye (Δ − Y) MV-level transformer is considered in this paper. Three identical SSIB converters transfer the power generated by each PV array to a common MV dc bus. At the same time, each SSIB converter controls the output voltage of their associated PV array. The voltage of theMV dc bus is controlled by the inverter, thus transferring all the available power to the electricity grid via an MV-level transformer.
- 4. Do Your Projects With Domain Experts… Copyright © 2015 LeMeniz Infotech. All rights reserved Page number 4 LeMeniz Infotech 36, 100 Feet Road, Natesan Nagar, Near Indira Gandhi Statue, Pondicherry-605 005. Call: 0413-4205444, +91 9566355386, 99625 88976. Web : www.lemenizinfotech.com / www.ieeemaster.com Mail : projects@lemenizinfotech.com Advantages: Input current ripple is decreased. Increasing the power rating of the converter. Applications: Photovoltaic (PV) systems.
- 5. Do Your Projects With Domain Experts… Copyright © 2015 LeMeniz Infotech. All rights reserved Page number 5 LeMeniz Infotech 36, 100 Feet Road, Natesan Nagar, Near Indira Gandhi Statue, Pondicherry-605 005. Call: 0413-4205444, +91 9566355386, 99625 88976. Web : www.lemenizinfotech.com / www.ieeemaster.com Mail : projects@lemenizinfotech.com Block diagram: INPUT DC supply Interleaved boost converter with voltage doubler cells Load OPTO Isolator circuit BUFFER circuit PIC controller circuit 5VDC 12 V DC
- 6. Do Your Projects With Domain Experts… Copyright © 2015 LeMeniz Infotech. All rights reserved Page number 6 LeMeniz Infotech 36, 100 Feet Road, Natesan Nagar, Near Indira Gandhi Statue, Pondicherry-605 005. Call: 0413-4205444, +91 9566355386, 99625 88976. Web : www.lemenizinfotech.com / www.ieeemaster.com Mail : projects@lemenizinfotech.com Tools and software used: MPLAB – microcontroller programming. ORCAD – circuit layout. MATLAB/Simulink – Simulation.