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.

In this paper, a soft switching interleaved boost converter (SS-IBC) using auxiliary resonant circuit for electric vehicles (EV) applications is proposed. Several phases of the proposed converter can be connected to make a multiphase interleaved boost converter. The operation of multiphase interleaved boost converter is identical to that of the one phase boost converter. All phases are ideally identical with shifted control signals and are controlled by PWM control strategy of equal switching frequency and duty cycle. The proposed converter can be considered as a cost effective retrofit to the grid integrated battery charging applications. It affords a steady electrical power for the load not only from the utility or classical energy storage systems as batteries, but also from renewable energy systems like photovoltaic (PV), wind or fuel cell systems. An appropriate design example demonstrates the size of the design circuit components and parameters are investigated. Analysis, design, and simulation of the presented converter are verified using PSIM simulation software on an 8.2 kW setup system with a conversion efficiency more than 97% over a wide output power conversion range from rated power to a minimum power of 460 W with complete soft switching operation. The converter performance is also validated experimentally on a downsized hardware rated 1.0 kW and the maximum efficiency is found to be 98.78%.

This paper introduces an interleaved buck-boost converter with reduced power electronics devices count in comparison with the conventional topology. The proposed converter consists of a single buck converter followed by $n$ parallel interleaved boost converters. The buck switch is gated only if any of the boost switches is gated. In addition to the reduced switches count, the proposed converter offers the following advantages, soft start-up and shutdown capabilities. In addition, the buck stage gives the ability to protect the power electronic devices and to isolate the supply during load failure or overload. Moreover, the proposed converter performs as an interleaved boost converter for high voltage gain requirements with the same switching scheme. Furthermore, it offers fast dynamic performance with smooth transition from the buck mode to the boost mode. This paper investigates the eight different operating zones of the proposed three-phase interleaved buck-boost converter for non-overlapping gate signals operation. The detailed analysis and zones of operation are presented and experimentally validated. In addition, a simple control system is presented to operate the proposed converter as dc-dc converter or ac-dc converter. More study cases are carried out to evaluate the different capabilities of the proposed converter.

This paper presents an isolated high-frequency (HF) multi-port dc/dc converter for PV interfacing systems. In the proposed multi-port converter, an HF transformer with multiple input windings and single output winding is utilized. Each input port is based on a proposed two-quadrant inverter topology which connects a PV module to the HF transformer. The output port is tied to a dc-bus using a rectifier. The proposed two-quadrant inverter topology prevents current flow from the ac-side to the dc-side. This action prevents circulating currents between different ports. Each two-quadrant inverter is controlled to harvest maximum power from its associated PV module. The analysis and operation scenarios of the proposed multi-port converter are discussed. PSCAD/EMTDC software package is used to simulate the proposed PV interfacing system to investigate the operation of the proposed multi-port converter topology and to examine the dynamic system behavior. In addition, an experimental prototype is developed to validate the operation scenarios of the proposed multi-port dc/dc converter and to examine the performance of the presented PV interfacing system.

A highly efficient photovoltaic (PV) system requires a maximum power point tracker to extract peak power from PV modules. The conventional variable step-size incremental conductance (INC) maximum power point tracking (MPPT) technique has two main drawbacks. First, it uses a pre-set scaling factor, which requires manual tuning under different irradiance levels. Second, it adapts the slope of the PV characteristics curve to vary the step-size, which means any small changes in PV module voltage will significantly increase the overall step-size. Subsequently, it deviates the operating point away from the actual reference. In this paper, a new modified variable step-size INC algorithm is proposed to address the aforementioned problems. The proposed algorithm consists of two parts, namely autonomous scaling factor and slope angle variation algorithm. The autonomous scaling factor continuously adjusts the step-size without using a pre-set constant to control the trade-off between convergence speed and tracking precision. The slope angle variation algorithm mitigates the impact of PV voltage change, especially during variable irradiance conditions to improve the MPPT efficiency. The theoretical investigations of the new technique are carried out while its practicability is confirmed by simulation and experimental results.

This article proposes a new active power flow controller for dc–dc multiactive bridge (MAB) converters with minimum current point tracking (MCPT) to minimize conductive losses. Unlike recent efforts in this area, the proposed controller does not require look-up table for implementation nor complex nonlinear converter modeling and is not circuit parameter dependent. The proposed control scheme is also generalized for MAB converters with any number of ports and is derived in per unit form to enable standard implementation for buck/boost/unity-gain operating modes. The proposed MCPT algorithm is based on an innovative adaptive perturb and observe tracking of the minimum current point (MCP) on the MAB converter current characteristic plane. This MCP is tracked while active power regulation is simultaneously achieved based on a new phase shift decoupler to enable direct regulation of individual port active power. Detailed design procedure of the proposed controller is presented and extensive simulation is carried out to validate the effectiveness of the proposed MCPT closed loop controller. Experimental implementation is also provided to substantiate the simulation results.