Modeling of the converters Essay
Modeling of the converters, 495 words essay example
The main purpose and advantage of using this strategy is to design a system such that it satisfies and meets the demand of a power supply and also maintain the state of charge and discharge in the batteries with a constraint value to avoid the blackouts in the system and also increase the life span of the energy storage system. As we are comparing and using two types of battery technologies it is necessary to ensure that the batteries used are reliable, operating optimally and are most importantly cost effective. In this particular system design, it is also important to take certain measures such as the PV profile, the load profile from the grid and the battery profile in to consideration. The energy or the power transfer in the system is being achieved by using an MPPT control strategy using a P&O algorithm to incorporate the power and the SOC of the battery and also a better regulation is determined. In the design there is battery charging and discharging control using the bi directional DAB and MPPT control in the solar PV.
B. Modeling of the converters
Good controller design requires good plant models. A high switching frequency power converter is essentially a nonlinear and time-varying system due to its switching nature. However, most control methodologies prefer a linear and time-invariant plant. Therefore, various modeling techniques have been proposed to approximate the nonlinearity and time-varying behaviors of a power converter and to provide a linear, time-invariant approximation of the power converter of interest.
The controller design for DAB converters, like other power converters, also requires an average model of DAB converters. Currently there are two approaches to model a DAB converter a simplified reduced-order model that neglects the transformer current dynamic. a full-order discrete time model that preserves the dynamic of transformer current. Discrete-time modeling is one approach to model those converters with large variation and resonant operations. However, a continuous-time model is usually preferred because it provides more physical insight and facilitates control design. The conventional state-space averaging technique for dc-dc converters requires negligible current ripple. However, this condition is not satisfied in DAB converters because the transformer current of a DAB converter is purely ac. Instead, the generalized averaging technique, which uses more terms in the Fourier series of state variables, is able to capture the effect of pure ac current on converter dynamics
C. Solar PV module
A solar PV module is the one which converts light
in to electricity and The energy output of such PV module will reach its peak at midday, meeting the daily energy consumption peak, when the spot prices on energy are highest. The figure below shows the PV power and VI characteristics of a solar PV module. The module is exposed to a irradiance of (1000 Wm-2) at a constant temperature at (250 C). This PV panel is connected to an MPPT control device and the panel is usually operated at a maximum power point for a better performance of the