Shahrin Md. Ayob

Single Input Fuzzy Logic Controller for Unmanned Underwater Vehicle

This paper describes a control scheme that provides an efficient way to design a Fuzzy Logic Controller (FLC) for the unmanned underwater vehicle (UUV). The proposed method, known as the Single Input Fuzzy Logic Controller (SIFLC), reduces the conventional two-input FLC (CFLC) to a single input single output (SISO) controller. The SIFLC offers significant reduction in rule inferences and simplify the tuning of control parameters. Practically it can be easily implemented by a look-up table using a low cost microprocessor due its piecewise linear control surface. To verify its effectiveness, the control algorithm is simulated using the Marine Systems Simulator (MSS) on the Matlab/Simulink® platform. The result indicates that both the SIFLC and CFLC give identical response to the same input sets. However SIFLC requires very minimum tuning effort and its execution time is in the orders of two magnitudes less than CFLC.

FPGA Implementation of a Single-Input Fuzzy Logic Controller for Boost Converter With the Absence of an External Analog-to-Digital Converter

In this paper, the single-input fuzzy logic controller (FLC) (SIFLC) for boost converter output-voltage regulation is proposed. The SIFLC utilizes the signed distance method that reduces the multidimensional rule table to 1-D with only one input variable, i.e., distance d. The simplification allows for the control surface to be approximated by a piecewise linear. It is shown that, despite the simplicity of SIFLC, its control performance is almost equivalent to that of the conventional FLC. As a proof of concept, the SIFLC is implemented using the Altera EP2C35F672C6N field-programmable gate array (FPGA) and applied on a 50-W boost converter. The SIFLC is compared to the proportional-integral controller; the simulation and practical results indicate that SIFLC exhibits excellent performance for step load and input reference changes. Another feature of this work is the absence of an external analog-to-digital converter (ADC). Instead, a simple analog-to-digital conversion scheme is implemented using the FPGA itself. Due to the simplicity of the SIFLC algorithm and the absence of an external ADC, the overall implementation requires only 408 logic elements and five input-output pins of the FPGA.

Analysis and simulations of Z-source inverter control methods

In this paper, two different control methods for Z-source inverter are examined. The Simple Boost and the Maximum Boost control methods of the inverter are analyzed and compared each other using simulation with MATLAB/Simulink. The Simple Boost control with independence relation between modulation index and shoot-through duty ratio is also simulated and analyzed. The selection of high modulation index and shoot-through duty ratio can reduce the inverters dc link voltage overshoot and increasing power delivery capacity of the inverter.

Trapezoidal PWM Scheme for Cascaded Multilevel Inverter

This paper proposes a new PWM switching strategy for the cascaded multilevel inverter (CMI). This scheme employs multiple trapezoidal modulation waveforms with a single triangular carrier. The main advantage of this technique is the ability to generate PWM waveform generation in real time using very simple algorithm. Furthermore it also results in higher fundamental component magnitude. Although it is known that trapezoidal modulation suffers from the presence of low-order harmonics, it can be minimized by appropriately selecting the slope angle of the trapezoidal, alpha. This paper carried out the simulation on a five level CMI to justify the merits of the proposed scheme. A low cost FPGA based single phase five-level CMI test-rig is also constructed to verify the simulation results.

Design of a current mode PI controller for a single-phase PWM inverter

This paper presents the design of current mode PI controller for single-phase PWM inverter. The controller is comprised of inductor current as the inner loop and output voltage as the outer feedback loop. The control design is carried out using Sisotool, which is provided in Matlab. By using this tool, users can examine the effects of changing the gain control values to systems transient response and stability, simultaneously. Hence, simplify and speed up the control design process. To evaluate the performance of the designed controller, the inverter is simulated under several types of load disturbances. From the result, it is shown that the designed controller exhibits a good transient response i.e. fast rising and settling time with small overshoot when subjected to step load disturbance.

Implementation of Single Input Fuzzy Logic Controller for Boost DC to DC power converter

This paper describes the application of the Single Input Fuzzy Logic Controllers (SIFLC) to regulate the output voltage of a Boost (step-up) DC to DC power converter. The SIFLC is derived from the Signed Distance Method which reduces the multi-input Fuzzy Logic Controller (FLC) with Toeplitz rule table structure to a single input FLC. Effectively, it allows for the rule table to be approximated to a one dimensional piecewise liner control surface. To validate the effectiveness of the SIFLC compared to the Conventional FLC, MATLAB is simulation carried out. Controller is implemented in digital using FPGA and experimental results are exhibited.

Sugeno-type fuzzy logic controller (SFLC) for a Modular Structured Multilevel Inverter (MSMI)

This paper presents a study on the performance of a Sugeno-type fuzzy logic controller (SFLC) as applied to a modular structured multilevel inverter (MSMI) to regulate its output voltage at a specified frequency. Simulation and analysis have been done, which includes comparison on the performance of the SFLC to that of the Mamdani-type fuzzy logic controller (MFLC), which has been conducted in a previous work. The proposed SFLC has shown good performance for closed-loop control of an MSMI during simulation using MATLAB/Simulink with higher execution speed compared to the MFLC.

A novel single phase five-level photovoltaic based grid-connected inverter

This paper presents a novel single-phase five-level inverter topology. It features a small number of component counts with low voltage stress across the power switches. Hence, increasing the reliability which is an issue for multilevel inverter. A detailed study of the proposed topology and its switching technique is outlined. The switching technique is specifically derived for the proposed topology. Suitable selection of switching pulse width and taping level ensures THD is around 16.48% (in output voltage) for proposed five-level inverter. The viability of proposed topology is validated through simulation.

Piecewise Linear Control Surface for Single Input Nonlinear PI-Fuzzy Controller

This paper presents an analysis on piecewise linear control surface for a single-input nonlinear PI Fuzzy controller. The analysis is carried out to determine the conditions that should be met in order for the piecewise linear control surface approximation to be validated. An equivalent two-input Pi-Fuzzy with conventional fuzzification, inference and deffuzification process is built for verification purpose and both controllers are then applied to a single phase inverter system. The dynamic response of both controllers are examined and compared. From the simulation results, it is shown that the approximation is valid.

Design and Implementation of a Single Input Fuzzy Logic Controller for Boost Converters

This paper describes the design and hardware implementation of a Single Input Fuzzy Logic Controller (SIFLC) to regulate the output voltage of a boost power converter. The proposed controller is derived from the signed distance method, which reduces a multi-input conventional Fuzzy Logic Controller (CFLC) to a single input FLC. This allows the rule table to be approximated to a one-dimensional piecewise linear control surface. A MATLAB simulation demonstrated that the performance of a boost converter is identical when subjected to the SIFLC or a CFLC. However, the SIFLC requires nearly an order of magnitude less time to execute its algorithm. Therefore the former can replace the latter with no significant degradation in performance. To validate the feasibility of the SIFLC, a 50W boost converter prototype is built. The SIFLC algorithm is implemented using an Altera FPGA. It was found that the SIFLC with asymmetrical membership functions exhibits an excellent response to load and input reference changes.