Multi-Input Inverter for Grid-Connected Hybrid PV/Wind Power System

Elegant Power Application Res. Center, Nat. Chung Cheng Univ., Chia-Yi
IEEE Transactions on Power Electronics (Impact Factor: 4.08). 06/2007; DOI: 10.1109/TPEL.2007.897117
Source: IEEE Xplore

ABSTRACT The objective of this paper is to propose a novel multi-input inverter for the grid-connected hybrid photovoltaic (PV)/wind power system in order to simplify the power system and reduce the cost. The proposed multi-input inverter consists of a buck/buck-boost fused multi-input dc-dc converter and a full-bridge dc-ac inverter. The output power characteristics of the PV array and the wind turbine are introduced. The perturbation and observation method is used to accomplish the maximum power point tracking algorithm for input sources. The operational principle of the proposed multi-input inverter is explained. The control circuit is realized by using a digital signal processor and auxiliary analog circuits. For practical applications, functions of soft-start and circuit protection are implemented. Experimental results have shown the performance of the proposed multi-input inverter with desired features

  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents a new extendable single-stage multi-input dc-dc/ac boost converter. The proposed structure comprises of two bidirectional ports in the converter's central part to interface output load and battery storage, and several unidirectional input ports to get powers from different input dc sources. In fact, the proposed topology consists of two sets of parallel dc-dc boost converters, which are actively controlled to produce two independent output voltage components. Choosing two pure dc or two dc-biased sinusoidal values as the converter reference voltages, situations of the converter operating in two dc-dc and dc-ac modes are provided, respectively. The proposed converter utilizes minimum number of power switches and is able to step up the low-level input dc voltages into a high-level output dc or ac voltage without needing any output filter. The converter control system includes several current regulator loops for input dc sources and two voltage regulator loops for generating the desired output voltage components, resulting in autonomously charging/discharging the battery to balance the power flow. Due to the converter inherent multi-input multioutput control system, the small signal model of the converter is extracted and then the pole-placement control strategy via integral state feedback is applied for achieving the converter control laws. The validity and effectiveness of the proposed converter and its control performance are verified by simulation and experimental results.
    IEEE Transactions on Power Electronics 01/2014; 29(2):775-788. · 4.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A smart grid will require, to greater or lesser degrees, advanced tools for planning and operation, broadly accepted communications platforms, smart sensors and controls, and real-time pricing. The smart grid has been described as something of an ecosystem with constantly communication, proactive, and virtually self-aware. The use of smart grid has a lot of economical and environmental advantages; however it has a downside of instability and unpredictability introduced by distributed generation (DG) from renewable energy into the public electric systems. Variable energies such as solar and wind power have a lack of stability and to avoid short-term fluctuations in power supplied to the grid, a local storage subsystem could be used to provide higher quality and stability in the fed energy. Energy storage systems (ESSs) would be a facilitator of smart grid deployment and a “small amount” of storage would have a “great impact” on the future power grid. The smart grid, with its various superior communications and control features, would make it possible to integrate the potential application of widely dispersed battery storage systems as well other ESSs. This work deals with a detailed updated review on available ESSs applications in future smart power grids. It also highlights latest projects carried out on different ESSs throughout all around the world.
    Smart Grid and Renewable Energy 02/2013; 4(1):122-132.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The selection of an optimal switching frequency of pulse width modulation (PWM) for single-phase inverters is one of the most effective ways to improve the inverters' efficiency. However, the lower switching frequency results in the higher harmonic voltage and current. For grid- connected inverters, the harmonic current distortion is significantly affected by the switching frequency. Therefore, the choice of switching frequency is usually considered as a tradeoff between lowering the total demand distortion (TDD) of output current and reducing the switching losses. In this paper, a variable switching frequency algorithm that changes the carrier frequency of a modified space vector pulse width modulation (SVPWM) control in real time based on different operating conditions is developed to improve the overall efficiency of the inverter while meeting a TDD requirement specified in IEEE Standard 1547. The performance of the proposed algorithm is verified by both Matlab-based simulation and experiments conducted on a 12kw single-phase inverter.
    Applied Power Electronics Conference and Exposition (APEC), 2013 Twenty-Eighth Annual IEEE; 01/2013