Matheepot Phattanasak

Control of a Hybrid Energy Source Comprising a Fuel Cell and Two Storage Devices Using Isolated Three-Port Bidirectional DC–DC Converters

This paper deals with a hybrid energy source consisting of a proton exchange membrane fuel cell, two storage devices, and a load. Generally, this type of source constitutes of nonisolated dc–dc converters. In order to have galvanic isolation for safety reasons and a high voltage ratio, we introduce another system based on the use of three-port isolated dc–dc converters. The storage device can be either a battery or a supercapacitor. This paper presents a control strategy for the hybrid source and includes a global efficiency analysis of power sharing between modules. The proposed system is validated through different simulation results. Additionally, some experimental results are given for the single module operation.

A dynamic equivalent circuit model for gas diffusion layers of PEMFC

Proton exchange membrane fuel cell (PEMFC) is a device that converts hydrogen and oxygen to electricity. Power electronic converter is an important equipment to transfer energy from PEMFCs to loads properly. The PEMFC model suited for integrating with power electronic circuit simulation are the empirical and the equivalent circuit types. The gas diffusion layer is important part of the PEMFC. This part determines the limit condition of the PEMFC. However, the equivalent circuit model of the gas diffusion layer is not available. This paper proposes a dynamic equivalent circuit model for the GDL and its simulation.

Switching command based on Lyapunov function for a boost converter with an LC input filter in dc microgrid application

This paper describes a method to control a boost converter with LC input filter working under continuous conduction mode. The idea of this method relies on Lyapunov stability criterion. All state variables are controlled in the same times. Therefore, the responses of this controlled system are fast. However, since the output command signal is generated directly from the controller, the switching frequency is not fixed. The experimental results validate the proposed control algorithm.

Flatness based control of a dual active bridge converter for DC microgrid

This paper proposes a nonlinear control for a dual active bridge converter (DAB) using properties of flatness system. This converter system is used for a DC microgrid. Losses in the system are modeled as a resistance connected in parallel with the output capacitor. The control algorithm also takes this resistance into account. With a small-scale test bench, bidirectional power flow capability is demonstrated. The effectiveness of the proposed system is demonstrated through experimental results.

Comparison of two nonlinear control strategies for a hybrid source system using an isolated three-port bidirectional DC-DC converter

This paper compares two nonlinear control strategies for a hybrid source system using an isolated three-port bidirectional full-bridge DC-DC converter. The system uses a fuel cell (FC) as a main energy source, a supercapacitor bank (SC) as an auxiliary source and a load. The first control strategy includes nonlinear and PI controller for which the dynamic response depends on the operating point. The second control strategy is based on the flatness controller which is independent from the operating point. The two control strategies allow taking into account practical constraints of the sources. Through experimental results, the proposed controllers are validated.

Current-fed full-bridge DC-DC converter with nonlinear control scheme

This paper presents a control algorithm for dealing with the constraints of energy power source and a current-fed full-bridge converter. The advantages of this control scheme include transient and steady-state responses and robustness. The prototype of 26 V/100 V 250 W and its controller were implemented. A dSPACE DS1104 was used to implement the outer control loop by using flatness systems properties. An analog control card was employed as an inner control loop by using hysteresis-based PWM. The validation of the proposed control was demonstrated through experiment results.

Differential flatness based control of supercapacitor substation for DC grid system

This paper presents a new control approach for dc-link stabilization in weak networks that use supercapacitors (SC) as the energy storage substation. A 4-phase parallel converter with interleaved switching technique is presented as a 2-quadrant SC converter, and a reduced-order mathematical model of the system is described for power plant control. Using a nonlinear control approach based on the flatness property, we propose a straightforward solution to dynamic and stabilization problems in the power electronics systems of networks, which is the key contribution described in this paper. To validate the proposed method, a hardware system is modeled using digital estimation with a DS1104 dSPACE controller platform. We analyze a prototype small-scale network that uses a 700 W six-pulse rectifier as a dc main generator and a 100 F, 32 V SC bank as an energy storage substation. Finally, the utility of the control algorithm is validated using experimental results measured during load cycles.

Control of a hybrid energy source comprising a fuel cell and two storage devices using isolated three-port bidirectional DC-DC converters

This paper deals with a hybrid energy source consisting of a proton exchange membrane fuel cell, two storage devices, and a load. Generally, this type of source constitutes of nonisolated dc-dc converters. In order to have galvanic isolation for safety reasons and a high voltage ratio, we introduce another system based on the use of three-port isolated dc-dc converters. The storage device can be either a battery or a supercapacitor. This paper presents a control strategy for the hybrid source and includes a global efficiency analysis of power sharing between modules. The proposed system is validated through different simulation results. Additionally, some experimental results are given for the single module operation.

A nonlinear control algorithm of Li-ion battery substation for DC distributed system

This paper presents a control algorithm for dc-bus stabilization in weak network that uses a Li-ion battery as the battery substation. The battery modules connected with 2-quadrant 4-phase parallel converter with interleaved technique. In this paper, a nonlinear control algorithm based on the flatness properties of the system is proposed. Using the flatness property, we propose simple solutions to dc distributed system and stabilization problems. A hardware system is implemented in laboratory. The prototype small-scale power plant is composed of a dc main source (80 V, 500 W), and a Li-ion battery module (11.6 Ah, 24 V). Experimental results substantiate the excellent control scheme during load cycles.

A Lyapunov function for switching command of a DC–DC power converter with an LC input filter

This paper describes a method to control a dc–dc switching power converter with an LC input filter working under continuous conduction mode. It is known that the interaction between the low-pass filter and the tightly controlled switching converter occurs, and it might lead to an instability operation. The idea of this method relies on the Lyapunov stability criterion. The switching command of this control is defined by the manner of pre-evaluating the stability of the controlled system. All state variables are controlled in the same time. Therefore, the responses of this controlled system are fast while guaranteeing a stable operation. The proposed control is applied to a boost converter to demonstrate the implementation and its performance. The simulation and experimental results validate the proposed control approach.