The rising demand for energy and the depletion of fossil fuels has led to the rapid adoption of renewable energy sources. However, their variability poses challenges. Battery-based storage systems offer a solution, storing excess energy for peak demand or low generation periods. High-gain converters are key in efficiently integrating these systems with the grid by boosting battery voltage. Adding cell-integrated power electronics enhances reliability by providing localized control, reducing the impact of individual cell failures. The study investigates the efficiency of cell-level high-gain DC-DC two-stage converters for integrating renewable energy into the grid. To optimize performance across diverse DC link voltages, a comparison of different first-stage converters is performed based on factors such as component selection and switch losses. Following careful calculations and selection, the chosen converter is paired with an inverter for seamless grid integration. Operating at a power level of 200W, the converters transform low battery cell voltage from 2.5V to 40V into a grid-compatible 360V output. Results demonstrate the selected converter's superior efficiency and voltage regulation, displaying its suitability for grid integration applications. This research underscores the importance of such converters in facilitating reliable renewable energy integration, offering a pathway toward sustainable energy utilization. In the subsequent phase, the investigation delves deeper into assessing the performance of the LLC converter, particularly focusing on how it reacts to the secondary effects of the converter. This investigation gives special attention to a significant factor known as Intra-Winding capacitance, which refers to the unintended capacitance existing within the windings of the converter's transformer in close proximity. Furthermore, this analysis employs the General Harmonic Approximation (GHA) and compared against traditional Fundamental Harmonic Approximation (FHA).

Switch-mode power converters operate at frequencies ranging from tens to hundreds of kilohertz and tend to generate significant conducted EMI within the regulated frequency band of 0.15-30 MHz. Converters typically require an input filter to comply with electromagnetic compatibility standards to prevent high-frequency currents from traveling through the power source conductors. The traditional EMI filters are usually made of passive components, which are substantial in size, sometimes occupying as much as one-third to one-fourth of the total volume, limiting the power density of the power converters. An alternative to bulky passive EMI filters is the utilization of active electronics, which inject voltages or currents to counteract the interference signal. This work introduces a boost converter in conjunction with a synchronized switch mode Active Electromagnetic Interference Filter (AEF), which reduces energy storage requirements compared to passive EMI filters. The proposed AEF operating at a frequency of 30 MHz effectively mitigates additional EMI into the system as its operational frequency lies beyond the typical range of conducted EMI. The AEF is realized using a synchronous buck converter with a series resonant tank and the current configuration is designed to counteract the ripple component of the boost converter. Firstly, this work presents the comprehensive analytical modeling of the AEF circuit consisting of a series resonant tank to determine the variation of AEF current magnitude to circuit parameters, and duty-controlled switching in the proposed AEF is implemented using high-speed analog circuits to generate pulse width modulated (PWM) signals for the filter. The proposed methodology controls the magnitude of AEF current to a desired value in an open loop to reduce the complexity of the circuit. Further, the AEF is employed in a (6-12)V-to-24V boost converter switching at 150 kHz and has been found to attenuate the fundamental ripple component. From the experimental results, an attenuation of 23dB is achieved using the proposed AEF and a reduction of LC product by a factor of 16 in the AEF and the effective volume of the AEF by 47% compared to that of a single-stage fully passive LC filter.