Battery Monitoring System and SOC Enhancement Analysis Using Artificial Intelligence Techniques

(a) Rise of Renewable Energy

The need for power is rising day to day while; non-renewable energy sources are rapidly exhausting. To devastate issues, effective and efficient electric power generation from RE source is necessary. Renewable energy sources are regarded as clean energy sources, since they produce little secondary waste, and have little influence on environment. The growth of renewable energy (RE) is crucial for addressing the energy problem and environmental pollution. Solar, wind, small hydro, biomass, tidal, and geothermal energy are some of the renewable resources that are commercially available for producing power. High power quality is a challenge in photovoltaic generation, yet PV power generation is becoming more popular these days. Generally, PV generator setup to supply nonlinear loads is preferred when it can also function as an active power filter (APF).

In power systems, the major concern lies in power quality. Delivery of quality power to the grid still remains a challenge to the researchers. Due to increased use of nonlinear loads, the effect of harmonics can be felt as a degradation of power quality. Grid-connected systems, nowadays, use PV power or any other form of non-conventional source due to numerous benefits. Among all the forms of non-conventional sources, PV power is viewed with great prospects due to easy availability. Over the past ten years, solar photovoltaic (PV) energy has grown in popularity among sources of renewable energy (RE).Solar PV based energy generating systems are widely used renewable resources because of their static structure, compact size, and nearly maintenance-free nature. It is anticipated that the photovoltaic (PV) system, which accounts for a sizeable share of global renewable energy, will contribute more to change in the power systems. As a result, many frequency management strategies for PV systems have been created. Since, PV systems are intermittent and engage low DC power, a converter operation is essential.

(b) Power Electronic Converters in PV-Grid Systems

Power electronic converters for use in PV-grid systems are predominantly used in recent times. This is because of the variation in the levels of voltage output which can be achieved by using boost/buck converters and also the ability of the converters to utilize the available form of supply to modulate and provide the output in the desired manner. In PV applications, boost converters are frequently employed for DC-DC conversion. A typical Boost converter is operated at a ratio of high duty cycle in order to generate a significant step-up voltage. However, the diode's reverse recovery time and the presence of parasitic elements cause a drop in the step-up ratio and reliability of the device. A DC-DC converter known as a “buck-boost converter” generates an inverted output voltage that is larger or lower than the input voltage. Although, typical buck-boost converter convert voltage in both step-up and step-down directions, its discontinuous input current prevents it from doing MPPT at its best without using a lot of decoupling capacitors. Generally, controller operation is important for a converter to extract maximum output power from PV systems. For standalone and grid-correlated photovoltaic applications, a number of maximum power point tracking (MPPT) algorithms with varying degrees of complexity, efficiency, and expenses have been proposed. The mechanism of Maximum Power Point Tracking (MPPT) functioning becomes challenging since DC current used by the PV panels is shared. The MPPT may not always be reached, even though the centralized inverter systems lower power loss inside power converters, the captured energy is reduced.

(c) Significance of SEPIC Converters

For sake of continuous input current, SEPIC operates on the combined concept of buck and boost converter. The converter acts as an excellent choice for PV techniques since the SEPIC idea is applicable for current and voltage applications. SEPIC converters, with their ability to boost the voltage, are widely preferred. Though, Cuk and SEPIC converters have uninterrupted input currents and can step down or up voltage, their high input power ripples still restrict the MPPT's efficiency because PV system will vary greatly near its maximum power point (MPP). In this work, SEPIC converters and a modified form of SEPIC converter for a PV-grid system that produces lesser harmonics compared to the standard SEPIC converter, is proposed. Also, the use of multiple SEPIC choppers is employed due to its low complexity.