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This paper proposes the control of single-phase split-source inverter (SSI) for a standalone PV application using model-predictive control scheme. The PV system under investigation consists of PV modules, single-phase SSI, battery bank for energy storage, and DC-DC bidirectional converter to allow for bidirectional power flow with the batteries. Maximum power is extracted from the PV array using PI-based incremental conductance method. Both the maximum power point tracking of the PV modules and the synthesis of the sinusoidal output load voltage are achieved using the SSI. The control of the bidirectional converter is carried out using PI controllers to regulate the DC-link voltage. Selection of the controllers parameters is achieved using Harris Hawks optimization technique. Simulation results show that the system has succeeded in producing a constant DC-link voltage and well-regulated AC load voltage with low THD under various operating conditions. Experimental results verify the system performance. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive and generalized analysis of the bidirectional dual active bridge (DAB) dc–dc converter using triple phase shift (TPS) control to enable closed-loop power regulation while minimizing current stress. The key new achievements are a generic analysis in terms of possible conversion ratios/converter voltage gains (i.e., Buck/Boost/Unity), per unit based equations regardless of DAB ratings, and a new simple closed-loop controller implementable in real time to meet desired power transfer regulation at minimum current stress. Per unit based analytical expressions are derived for converter ac rms current as well as power transferred. An offline particle swarm optimization (PSO) method is used to obtain an extensive set of TPS ratios for minimizing the rms current in the entire bidirectional power range of –1 to 1 per unit. The extensive set of results achieved from PSO presents a generic data pool, which is carefully analyzed to derive simple useful relations. Such relations enable a generic closed-loop controller design that can be implemented in real time avoiding the extensive computational capacity that iterative optimization techniques require. A detailed Simulink DAB switching model is used to validate the precision of the proposed closed-loop controller under various operating conditions. An experimental prototype also substantiates the results achieved. [ABSTRACT FROM AUTHOR]

Hybrid multilevel converters are contemplated in an attempt to optimize the performance of voltage source converters in terms of magnitude of semiconductor losses and converter footprint, and to achieve additional features such as dc short circuit proof, which is essential for a high integrity multiterminal HVDC grid. Therefore, this paper considers an emerging hybrid cascaded converter that offers the dc side short circuit proof feature at reduced loss and footprint compared to the existing multilevel and other hybrid converters. Its operating principle, modulation, and capacitor voltage balancing strategies are described in detail. Furthermore, hybrid converter scalability to high voltage applications is investigated. The validity of the modulation and capacitor voltage strategy presented are confirmed using simulation and experimentation. The hybrid cascaded converter is extendable to a large number of cells, making it applicable to high voltage applications, and operation is independent of modulation index and power factor. On these ground, the converter is expected to be applicable for both real and reactive power applications. [ABSTRACT FROM AUTHOR]

The back-to-back (BTB) converter is used in power conversion applications such as machine drives, wind energy conversion systems (WECS), uninterruptible power supplies and high-voltage, direct current transmission systems. Various topologies have evolved around voltage source converters and current source converters (CSCs) in an attempt to meet various design and reliability constraints. This paper proposes a new CSC-based BTB converter suitable for WECS application. The proposed configuration addresses the main drawbacks of the conventional BTB CSCs, such as the over-voltage frequently experienced by switches during commutation. The inverter side converter has zero switching losses. The proposed WECS offers the following advantages: simple and easy control, reduced switching frequency and maximum power point tracking with controllable grid active and reactive power. A low-voltage ride-through (LVRT) solution is also provided in the proposed WECS. PSCAD/EMTDC simulation is used to assess the steady-state and dynamic behaviours of the proposed system under different operating conditions and during LVRT. Experimental results allow steady-state and dynamic behaviour assessment of the proposed system under different operating conditions. [ABSTRACT FROM AUTHOR]

The suitability of a single-stage ac-dc buck-boost converter for low-voltage applications is investigated. In-depth discussion and analysis of the converter's operating principle, basic relationships that govern converter steady-state operation and details of the necessary control structures needed to comply with the grid code are provided. The validity of the proposed system is confirmed using power system computer aided design (PSCAD)/electromagnetic transients including DC (EMTDC) simulations, and is substantiated experimentally. The buck-boost converter under investigation has good dynamic performance in both buck and boost modes, and ensures near unity input power factor over the full operating range, whilst having fewer devices and passive elements than other published versions of the buck-boost converter. [ABSTRACT FROM AUTHOR]