Electrical Design of a Portable Pure Sine Wave Inverter Using Ferrite Core Transformer and Double Stage Technique

The size of the iron core transformer in an inverter is large and heavy because it has more conductor turns and works at low frequencies. In contrast, ferrite core transformers are designed to work at high frequencies, so the number of turns of the conductor is less, and the transformer size is relatively small and light. Device portability is a significant challenge in designing high-power inverters. This research uses a ferrite core transformer to design a portable pure sine wave inverter. A two-stage technique is proposed in designing the inverter so that the dc-link voltage and capacitor size can be flexibly selected, and the device size can be compacted. The design consists of two stages. First, a circuit to generate a 400-Volt DC voltage is designed using IC SG3525, a MOSFET power amplifier, and a ferrite core step-up transformer. Second, a pure sine wave generator circuit is constructed using an EGS002 module, MOSFETs, and a filter circuit. Experiments are performed by measuring the output voltage, monitoring power and frequency, and observing the waveform with an oscilloscope. The results reveal that the designed inverter can generate a 220-volt pure sine wave output, a maximum power of 500 Watts, a frequency of 50 Hz, and an efficiency between 91.4% to 98.1%

Advanced Solutions for Renewable Energy Integration into the Grid Addressing Intermittencies, Harmonics and Inertial Response

Numerous countries are trying to reach almost 100\% renewable penetration. Variable renewable energy (VRE), for instance wind and PV, will be the main provider of the future grid. The efforts to decrease the greenhouse gasses are promising on the current remarkable growth of grid connected photovoltaic (PV) capacity. This thesis provides an overview of the presented techniques, standards and grid interface of the PV systems in distribution and transmission level. This thesis reviews the most-adopted grid codes which required by system operators on large-scale grid connected Photovoltaic systems. The adopted topologies of the converters, the control methodologies for active - reactive power, maximum power point tracking (MPPT), as well as their arrangement in solar farms are studied. The unique L(LCL)2 filter is designed, developed and introduced in this thesis. This study will help researchers and industry users to establish their research based on connection requirements and compare between different existing technologies. Another, major aspect of the work is the development of Virtual Inertia Emulator (VIE) in the combination of hybrid energy storage system addressing major challenges with VRE implementations. Operation of a photovoltaic (PV) generating system under intermittent solar radiation is a challenging task. Furthermore, with high-penetration levels of photovoltaic energy sources being integrated into the current electric power grid, the performance of the conventional synchronous generators is being changed and grid inertial response is deteriorating. From an engineering standpoint, additional technical measures by the grid operators will be done to confirm the increasingly strict supply criteria in the new inverter dominated grid conditions. This dissertation proposes a combined virtual inertia emulator (VIE) and a hybrid battery-supercapacitor-based energy storage system . VIE provides a method which is based on power devices (like inverters), which makes a compatible weak grid for integration of renewable generators of electricity. This method makes the power inverters behave more similar to synchronous machines. Consequently, the synchronous machine properties, which have described the attributes of the grid up to now, will remain active, although after integration of renewable energies. Examples of some of these properties are grid and generator interactions in the function of a remote power dispatch, transients reactions, and the electrical outcomes of a rotating bulk mass. The hybrid energy storage system (HESS) is implemented to smooth the short-term power fluctuations and main reserve that allows renewable electricity generators such as PV to be considered very closely like regular rotating power generators. The objective of utilizing the HESS is to add/subtract power to/from the PV output in order to smooth out the high frequency fluctuations of the PV power, which may occur due to shadows of passing cloud on the PV panels. A control system designed and challenged by providing a solution to reduce short-term PV output variability, stabilizing the DC link voltage and avoiding short term shocks to the battery in terms of capacity and ramp rate capability. Not only could the suggested system overcome the slow response of battery system (including dynamics of battery, controller, and converter operation) by redirecting the power surges to the supercapacitor system, but also enhance the inertial response by emulating the kinetic inertia of synchronous generator