Output Elementary Luo Converter Research Articles

Robust Reference Tracking and Load Rejection on Non-Linear System Using Controllers

DC-DC converters form a class of highly nonlinear systems and are widely used in most practical applications. Positive Output Elementary Luo Converter (POELC) is a fourth-order converter used to regulate dc voltages in low power applications with varying input voltage and load conditions. POELC is employed to regulate dc voltages for sensitive load applications like SMPS, powering hard disks etc. The control of higher-order converters is always a challenging task due to the highly nonlinear nature of these converters. Hence the development of an optimal controller for POELC is proposed in this paper. The proposed control methods are investigated for transient and steady-state performances considering practical operating conditions. The controllers are designed, simulated and the performance of POELC with various controllers is evaluated in the MATLAB/Simulink environment. The PI controller exhibits better performance in the linear region whereas, in the nonlinear region, due to time variance and switching nature. To minimize the sensitivity to external disturbances and to improve the stability margins, an LQR is designed to regulate the output of POELC. The result shows that a well-designed LQR feedback can stabilize the system and enhances its performance in terms of Integral Absolute Error (IAE), Integral Square Error (ISE). Certain case studies are discussed concerning practical applications.

Design and Analysis of a Voltage-Mode Non-Linear Control of a Non-Minimum-Phase Positive Output Elementary Luo Converter

The positive output elementary Luo (POEL) converter is a fourth-order DC–DC converter having highly non-linear dynamic characteristics. In this paper, a new dynamic output voltage feedback controller is proposed to achieve output voltage regulation of the POEL converter. In contrast to the state-of-the-art current-mode controllers for the high-order boost converters, the proposed control strategy uses only the output voltage state variable for feedback purposes. This eliminates the need for the inductor current sensor to reduce the cost and complexity of implementation. The controller design is accompanied by a strong theoretical foundation and detailed stability analyses to obtain some insight into the controlled system. The performance of the proposed controller is then compared with a multi-loop hysteresis-based sliding-mode controller (SMC) to achieve the output voltage-regulation of the same POEL converter. The schemes are compared concerning ease of implementation, in particular, the number of state variables and current sensors required for implementation and the closed-loop dynamic performance. Experimental results illustrating the features of both controllers in the presence of input reference and load changes are presented.

Single‐phase front‐end modified interleaved Luo power factor correction converter for on‐board electric vehicle charger

SummaryThis paper proposes a modification in the interleaved negative output elementary Luo converter to act as front‐end power factor correction converter for on‐board electric vehicle (EV) charger. The proposed converter is simple in design and offers non‐inverted DC link output voltage. The proposed converter has the advantages—high efficiency, near unity power factor, low AC source current distortion resulting in power quality enhancement, better DC load voltage regulation, and reduced component count. Due to interleaved configuration, rating of circuit components gets greatly reduced. Also, minimum numbers of circuit components pave the way for simple system design of on‐board EV charger. The steady‐state performance of the designed 100‐W, 48‐V converter with closed‐loop controller is analyzed under universal input voltage variation and wide range of load power variation. The converter is designed to provide stable operation when subjected to sudden disturbance in load power/supply voltage. The simulation analysis is done using MATLAB/Simulink platform. A prototype of 48‐V, 100‐W converter is built and tested. Results obtained reveal the superior performance of proposed converter under steady‐state and transient conditions.

Error minimization of positive output luo converter using various optimization techniques

DC-DC converters are widely used in many consumer electronic devices such as computers, medical equipment, battery chargers, cellular phones and many Industrial drives. These electronic devices require different voltage levels which is supplied from battery or some external supply. In multiple battery mission voltage decays as its stored energy is drained and requires large saving space. The switched DC-DC converters overcome these drawbacks and also regulate the output voltage for different power levels efficiently. This paper elaborates the structure of Luo converter with optimized PI controller. Positive Output Elementary Luo Converter (POELC) is designed for boost operation by choosing the appropriate duty cycle. The PI controller parameters are optimized using Cuckoo and Crow search algorithms. The proposed control methods are investigated for the transient and steady state region. The sensitivity of these controllers to supply load and line disturbances are also studied along with the servo response are presented. The controller incorporates a Luo converter is evaluated in terms of Integral Time Square Error (ITSE) and Integral Time Absolute Error. Dynamic modelling of the power converter is derived by using state space averaging method. The simulation model of the Luo converter with its control circuit is implemented in MATLAB/SIMULINK. Experimental result shows that Cuckoo PI controller has significantly performance improvement in comparison with both the conventional and Crow PI controller.

Positive output elementary Luo converter for fixed-frequency ZVS operation

Abstract Luo converter is one amid the developed DC-DC converters offering higher voltage gain. Soft-switching techniques, like zero-voltage switching (ZVS), repress switching losses, and hence the system efficiency and the life of the power semiconductor switches are improved. Incorporation of soft switching in fixed-frequency operation of the Luo converters may persuade them in the regulated power supply applications. The existing variable switching frequency solution suffers from a number of problems viz. complexity in filter designing, more electromagnetic interference (EMI), etc. This paper proposes a positive output elementary Luo converter (POELC) involving ZVS with the wherewithal of working in fixed frequency. A comprehensive discussion on the proposed circuit topology is detailed with both simulation and experimental studies. Systematic descriptions of basic POELC, variable-frequency ZVS-POELC, and fixed-frequency ZVS-POELC make an impact on the understanding of related concepts by the researchers in this field.

Solar Powered Luo Converter for Wiper Motor Application

Objectives: This paper is to design a positive output elementary luo converter whose output can be used to power the wiper motor. Method/Statistical Analysis: The perturb and observe algorithm is used to obtain the maximum power from the solar panel. The positive output luo converter is simulated using MATLAB/Simulink software. Findings: In conventional converters the output voltage increases in arithmetic progression. But, in luo converter the output voltage increases in geometric progression, thus the voltage gain of the converter is enhanced than conventional converters. The output of the luo converter is validated with r-load and motor load. With the help of luo converter, the ripple content in the output can be highly reduced in the output. Applications: Wiper motors are used for applications such as to operate wiper blades in car, automatic parking system, wheel movement in robots etc.

Comparative study of current‐mode controllers for the positive output elementary Luo converter via state‐space and frequency response approaches

This study presents the comparative study of dual-loop current-mode controllers to achieve the output voltage regulation of the positive output elementary Luo (POEL) converter. The POEL converter is a fourth-order dc–dc boost converter developed using the voltage lift technique that gives a positive load voltage. Two current-mode controllers, one using the input inductor current and one using the output inductor current, are studied. Both state-space and frequency response approaches are used in the study to obtain a better insight of the comparative study. It is demonstrated that the controller using the input inductor current is more suitable for the regulation of the POEL converter. Experimental results showing the features of the controller in the presence of load and reference voltage changes are also provided to validate the theoretical conclusions.

Optimization of PI Controller using PSO for Power Electronic Converter

DC-DC converters are widely used in application such as computer peripheral power supplies, car auxiliary power supplies and medical equipment's. Positive output elementary Luo converter performs the conversion from positive source voltage to positive load voltage. Due to the time- varying and switching nature of the power electronic converters, their dynamic behavior is highly non-linear. Conventional controllers are incapable of providing good dynamic performance and hence optimized techniques have been developed to tune the PI parameter. In this work, Particle Swarm Optimization (PSO) is developed for PI optimization. Simulation results show that the performances of PSO-PI controllers are better than those obtained by the classical ZN-PI controller.

Sliding-mode control for dc–dc converters with constant switching frequency

A new approach implementing the sliding-mode controller is proposed for dc-dc converters. The equivalent control input is used as the system control input, which results in a duty cycle regulation control system. As designed, equivalent control input is maintained at a value between 0 and 1, similar to the desired duty cycle value. Thus, constant switching frequency can be achieved under changes of state conditions. Two sliding-mode controllers based on this method are designed for positive output elementary Luo converter. Traditional small-signal analysis is applied to study the close-loop system performance under proposed approach. Audio-susceptibility, control-to-output transfer functions and output impedance are derived on the basis of the small-signal model. It is shown that the proposed sliding-mode control approach retains the advantages of traditional sliding-mode control, as well as achieve constant switching frequency, which is decided by the input saw-tooth waveform. Results of the experiment are reported for both controllers and they verify the theoretical analysis.