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Synchronous rectifier schemes for the resonant dc–dc converter significantly improve the power conversion efficiency. The predictive synchronous rectification scheme for an LCLC resonant converter for a battery charging and telecom application is proposed in this work. During converter operation, the resonant capacitor voltage is sensed through an analog to digital converter, and based on the discretized time domain equations, the turn-on and turn-off instances are precisely computed using computation and synchronous MOSFET on time predictor block for varying switching frequency of operation. The proposed predictive technique eliminates the need for current sensors, reducing overall system cost and conduction loss associated with it. The proposed predictive synchronous rectification method is tested in a 1 kW hardware prototype for varying line and load conditions. The proposed control scheme is able to track turn-on and turn-off instances precisely with a low timing error of 2% to 3% of the synchronous MOSFET ON time.

Transformerless inverters are a popular choice in Photovoltaic (PV) generation systems because of their cost-effectiveness and highly efficient operation. Nonetheless, challenges associated with common-mode voltage have motivated the exploration of alternative topologies, control methodologies, and modulation strategies. In common-ground type inverters, the load and source ground terminals are interconnected, resulting in the bypassing of parasitic capacitances and the complete elimination of leakage current. This paper proposes a novel eleven-level switched-capacitor based inverter topology featuring a common ground connection between the source and load. This topology can achieve a five-fold voltage gain, making it well suited for low-voltage PV systems. The common-ground (CG) feature of this inverter effectively eliminates leakage current and significantly reduces electromagnetic interference (EMI) by bypassing stray capacitance. Consequently, there is no need for an EMI filter. The voltage balancing of the capacitors occurs automatically, without the need for any control scheme, sensors, or closed-loop controllers. A detailed comparison with established CG-based topologies is carried out, emphasizing the parameters of component count, total standing voltage, cost, and volume, which clearly indicate the inverter's improved attributes. The pulse width modulation (PWM) scheme, design guidelines for the switched-capacitor (SC), and loss analysis, including thermal modeling, are discussed in detail. The proposed inverter's feasibility and performance are verified through detailed simulation and experimental studies.

Hardware design engineers use real-time testing platforms (RTP) to design and implement the power electronic converters (PEC). Digital signal processors (DSP) as a digital platform have an easy coding syntax for mathematically intensive control algorithms and implementation. They have fast processing and computational capabilities with the help of digital signal processors (DSP). The newly introduced DSPs have multi-cores and higher clock speeds, making them capable of real-time applications. In this context, this paper explores the possibility of using DSPs as cost-effective real-time testing platforms. The paper proposes using elemental real-time models to evaluate the system behavior and controller performance. The proposed elemental real-time model testing platform is validated for a buck converter, a series resonant dual active bridge converter (SRDAB), and a grid-connected inverter (GCI) system. This work aims to present a simple and fast low-cost testing platform, thus reducing the lead time for system development. The real-time simulation data from RTP and MATLAB simulation data are verified with experimental data. It is shown that the DSP-based real-time testing approach provides validated, low-cost solutions for real-time testing platforms.

A reconfigurable gain circuit is proposed for an LCLC resonant converter with bidirectional capability considering wide varying redox flow battery source. A suitable hybrid control scheme for LCLC resonant converter with secondary synchronous rectifier is proposed in this work. The proposed reconfigurable circuit enables to configure secondary bridge as an active voltage doubler, full-bridge circuit during forward power transfer mode and reverse power transfer mode, respectively. The reconfigurability helps significantly to design a transformer with lower secondary turns and achieve desired high gain. The reduced transformer secondary turns result in reduced transformer parasitics. The presence of LCLC resonant tank helps to provide the additional gain; the hybrid control scheme ensures zero-voltage switching turn-on for the primary, and secondary synchronous mosfets throughout the operating range. The proposed converter is analysed using fundamental harmonic approximation. The proposed reconfigurable gain circuit and hybrid control scheme is verified experimentally for an 800 V/1 kW hardware prototype fed from 24 to 54 V input.

This article proposes a fixed zone perturb and observe (FZPO) technique to achieve improved steady-state efficiency and a fast and drift-free maximum power point tracking (MPPT) for photovoltaic (PV) systems without any additional sensors. In this technique, the PV array’s power–voltage (P–V) curves are divided into multiple zones with unique zone boundary voltages for different irradiance conditions. This technique employs a combination of adaptive and fixed step sizes to improve the performance, where the adaptive step size is calculated from simple mathematical equations, resulting in a reduced computational burden. Besides, natural drift-free tracking is achieved without any additional sampling or computation, overcoming existing techniques’ limitations. The FZPO technique requires a PV panel’s information only at the initial design stage but not during real-time tracking, making the implementation possible using only low-cost processors. This article presents the implementation and design of the proposed controller. The FZPO technique’s performance is validated through a comprehensive set of hardware experiments on a buck–boost full-bridge (BBFB) converter under various irradiance conditions per the EN50530 standard. For a step change in irradiance, the FZPO technique is experimentally verified to be 42% and 20% more efficient than the conventional and VSS techniques, respectively. During the irradiance varying conditions using the FZPO technique, the peak power loss is one-sixth compared to the conventional and VSS techniques. Practical field-related considerations, such as PV panel temperature effects, are further investigated through experiments.

This paper proposes a combined adaptive droop-based load sharing, maximum power point tracking (MPPT), and energy management of photovoltaic (PV)-based dc microgrid system. A proportional droop index (PDI) algorithm is introduced, which is a function of normalized current sharing difference and voltage deviation at the output side of the converter. The proposed method calculates adaptive virtual resistance $R_{\textrm {droop}}$ , which allows the PV converter to operate at MPP or load sharing mode. By fine-tuning $R_{\textrm {droop}}$ values, the proposed method eliminates poor voltage regulation issues of the conventional droop method. The control of the hybrid energy storage system (HESS) with a battery and a supercapacitor (SC) is also discussed to stabilize the dc grid voltage and energy management of the dc microgrid. The detailed analysis and the design procedure of low-voltage (LV) dc microgrid systems are explained, and the effectiveness of the proposed method is verified by simulation and experimental studies.