VHDL-AMS based genetic optimisation of fuzzy logic controllers

Purpose – This paper presents a VHDL-AMS based genetic optimisation methodology for fuzzy logic controllers (FLCs) used in complex automotive systems and modelled in mixed physical domains. A case study applying this novel method to an active suspension system has been investigated to obtain a new type of fuzzy logic membership function with irregular shapes optimised for best performance. Design/methodology/approach – The geometrical shapes of the fuzzy logic membership functions are irregular and optimised using a genetic algorithm (GA). In this optimisation technique, VHDL-AMS is used not only for the modelling and simulation of the FLC and its underlying active suspension system but also for the implementation of a parallel GA directly in the system testbench. Findings – Simulation results show that the proposed FLC has superior performance in all test cases to that of existing FLCs that use regular-shape, triangular or trapezoidal membership functions. Research limitations – The test of the FLC has only been done in the simulation stage, no physical prototype has been made. Originality/value – This paper proposes a novel way of improving the FLC’s performance and a new application area for VHDL-AMS

Measurements, Models, Systems and Design

531 s.

High efficiency smart voltage regulating module for green mobile computing

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.In this thesis a design for a smart high efficiency voltage regulating module capable of supplying the core of modern microprocessors incorporating dynamic voltage and frequency scaling (DVS) capability is accomplished using a RISC based microcontroller to facilitate all the functions required to control, protect, and supply the core with the required variable operating voltage as set by the DVS management system. Normally voltage regulating modules provide maximum power efficiency at designed peak load, and the efficiency falls off as the load moves towards lesser values. A mathematical model has been derived for the main converter and small signal analysis has been performed in order to determine system operation stability and select a control scheme that would improve converter operation response to transients and not requiring intense computational power to realize. A Simulation model was built using Matlab/Simulink and after experimenting with tuned PID controller and fuzzy logic controllers, a simple fuzzy logic control scheme was selected to control the pulse width modulated converter and several methods were devised to reduce the requirements for computational power making the whole system operation realizable using a low power RISC based microcontroller. The same microcontroller provides circuit adaptations operation in addition to providing protection to load in terms of over voltage and over current protection. A novel circuit technique and operation control scheme enables the designed module to selectively change some of the circuit elements in the main pulse width modulated buck converter so as to improve efficiency over a wider range of loads. In case of very light loads as the case when the device goes into standby, sleep or hibernation mode, a secondary converter starts operating and the main converter stops. The secondary converter adapts a different operation scheme using switched capacitor technique which provides high efficiency at low load currents. A fuzzy logic control scheme was chosen for the main converter for its lighter computational power requirement promoting implementation using ultra low power embedded controllers. Passive and active components were carefully selected to augment operational efficiency. These aspects enabled the designed voltage regulating module to operate with efficiency improvement in off peak load region in the range of 3% to 5%. At low loads as the case when the computer system goes to standby or sleep mode, the efficiency improvent is better than 13% which will have noticeable contribution in extending battery run time thus contributing to lowering the carbon footprint of human consumption

Low cost microcontroller implementation of Takagi–Sugeno Fuzzy MPPT controller for photovoltaic systems

Maximum power point trackers have a significant role in optimizing the energy conversion efficiency in a photovoltaic system. The numeric achievements of MPPT algorithm can be implemented and tested by using several embedded boards as Digital Signal Processor, Field-Programmable Gate Array, Arduino, and dspace. Alternatively, for the low cost, availability and simplicity, the PIC microcontrollers can be used compared with the other hardware devices. Therefore, this paper presents the implementation of a Takagi–Sugeno fuzzy controller on a low cost PIC microcontroller, for tracking the maximum power point of a PV module. The PV system consists of a PV emulator, DC-DC converter, and resistive load. The different steps in design, simulation and realization of the T-S Fuzzy logic controller are discussed. The proposed controller system was evaluated by comparing its performance metrics, in terms of efficiency and the Integral Square Error, with existing technique in the literature. The results corresponding to the experimental validation show that the proposed MPPT controller is able to ensure a perfect tracking of the maximum power point with variation of irradiance and is performing better than reported in a previous work

Automated Solar PV Simulation System Supported by DC–DC Power Converters

Funding Information: This work was funded by Instituto Politécnico de Lisboa, reference code: IPL/2021/ATS2SPV_ISEL. Publisher Copyright: © 2023 by the authors.Solar photovoltaic simulators are valuable tools for the design and evaluation of several components of photovoltaic systems. They can also be used for several purposes, such as educational objectives regarding operation principles, control strategies, efficiency, maintenance, and other aspects. This paper presents an automated solar photovoltaic simulation system with the capability to generate automated tests considering different parameters of solar photovoltaic panels and different operation conditions. The proposed simulator is composed of three buck-boost DC–DC power converters controlled in such a way that will behave similarly to solar photovoltaic panels. It allows to introduce additional variable loads and maximum power point tracker algorithms similar to real systems. Some converters are controlled by a DSP microcontroller connected to a single programmable logic controller which generates the automated tests. Thus, using the presented solution, it is possible to implement the I-V and P-V characteristic curves of solar photovoltaic panels and evaluate different maximum power point tracker algorithms considering different meteorological conditions and load variations, being a useful tool to teach subjects related to renewable energy sources and related applications. Several simulation results using Matlab/Simulink and experimental results are presented to validate the operation of the proposed solution. Experimental results achieve a ripple between 2% and 5% of the desired average current in MPP conditions.publishersversionpublishe

The design, management and testing of a solar vehicle's energy strategy

In recent years the interest in implementing solar energy on vehicles (electrical and hybrid) has grown significantly [1]. There are currently limitations in this sector, such as the low energy density (efficiency of conversion) of this source, but it is still a renewable resource and as such, there is a growing interest [1]. A “smart” energy strategy implemented on a solar/electrical vehicle, in order to increase its energy harvesting volume, could enhance the growth of this sector. A tracking algorithm for a solar vehicle’s MPPT (Maximum Power Point Tracker) can be designed to source solar energy very effectively and to increase the speed of finding (tracking) this optimal sourcing point (solar panel voltage and current). Even though there are many different MPPT algorithms, it was decided that most of them were designed for stationary MPPT applications and the dynamics of implementing a MPPT on a vehicle create some unique scenarios. These include: Shadow flicker. This is rhythmic, rapid moving shadows across a solar panel, such as shadows from a line of trees: Rapid changes in solar panel orientation due to the road surface/relief; Rapid changes in panel temperature due to the location of the vehicle. The aim of the research can be divided into three outcomes: 1 Creating a “Smart” energy strategy/control, 2 Implement the new control system on a solar vehicle’s MPPT, and 3 Harvesting maximum energy from solar panels using the new energy strategy. The term “smart” is used to indicate the ability of the MPPT algorithm to be updated and improved based on previous results. A MPPT and scaled solar vehicle is designed and manufactured in order to test the MPPT algorithm. The purpose of using a self-developed experimental setup is to have more control over the system variables as well as having the maximum freedom in setting up the system parameters