Tao Zhou

Real-Time Emulation of a Hydrogen-Production Process for Assessment of an Active Wind-Energy Conversion System

This paper presents the real-time emulation of a hydrogen-production process for assessment of an active wind- energy conversion system. The hardware-in-the-loop emulator of the electrolyzer consists of a power-electronic stage and a control stage. In the control board, the algorithmic equations of the electrolyzer modeling and its control should be implemented, as well as the emulators power converter control. The causal ordering graph is used to model the electrolyzer and its auxiliary equipment. This model is capable of characterizing the relations among the different physical quantities and can be used to design the control system, ensuring an efficient and reliable operation of the electrolyzer. The proposed control method can manage the power and hydrogen flows. The simulation results have highlighted the variation domains and the relations among different physical quantities. The experimental results of the real-time emulation is based on a PHOEBUS advanced alkaline electrolyzer and shows the same electrical characteristics in real time with hardware.

Design of a power management system for an active PV station including various storage technologies

A hybrid power system with a PV energy conversion system is proposed with lead-acid batteries based long-term storage units and ultracapacitors based fast-dynamic storage units in a DC-coupled structure. It is necessary and important to manage the powers among those different power sources. A power management algorithm is proposed for this hybrid power system by taking into account the characteristics of each power source. It carries out the calculation and the power distribution of an adjustable power margin for the power sources. As results, the lead-acid batteries can smooth the generated fluctuating photovoltaic power in a long time range (from minutes to hours), and the ultracapacitors can smooth the photovoltaic power in a short time range (from seconds to minutes).

Power flow control in different time scales for a wind/hydrogen/super-capacitors based active hybrid power system

A hybrid power system is proposed and is based on wind energy conversion system with hydrogen based long-term storage unit and super-capacitor based fast-dynamic storage unit. A power management algorithm is organized in different time scales for its normal operating mode. Four studied cases show that, the long-term storage can compensate or absorb the difference between the generated fluctuating wind power and the grid power consumption in a long time range, and the fast-dynamic storage can smooth the power delivered to the grid in a short time range. It proves also the necessity of the three types of power sources.

Modeling and Control Design of Hydrogen Production Process by Using a Causal Ordering Graph for Wind Energy Conversion System

This paper gives a control oriented modeling of an electrolyzer, as well as the ancillary system for the hydrogen production process, by using causal ordering graph. The control system has also been proposed to manage the power flow and hydrogen flow. The simulation results have highlighted the variation domains and dynamics of physical quantities.

ADC architecture with direct binary output for digital controllers of high-frequency SMPS

Without adopting encoder to convert thermometer code into binary code, analog-to-digital converter (ADC) architecture with direct binary code output is proposed for digital controllers of high-frequency switching mode power supply (SMPS). It can provide large conversion ranges with required precision and reduce ADC circuit complexity. The output can be compressed into a much shorter addressing character in logarithmic law and lead to reduction of memory size in the look-up table of the digital compensator

Analog-to-digital converter architectures for digital controller of high-frequency power converters

This paper presents a survey and a classification of architectures for analog-to-digital converter (ADC) targeting digital control for high-frequency switching DC-DC power converters. Previously presented designs are identified as particular cases of the proposed classification. An ADC architecture with direct binary code output is also proposed and uses simple encoder to convert exponentially weighted thermometer code into binary code. Its output can be compressed into a much shorter word in logarithmic law to serve as addressing character for look-up tables in digital regulator

Flash ADC with Large Conversion Range for Digital Controller of High-Frequency Power Converter

Without adopting encoder to convert thermometer code into binary code, a flash analog-to-digital converter (ADC) architecture with direct binary code output is proposed for digital controllers of high-frequency power converters. It can provide a large regulation range with required high precision and the low complexity of the logic circuit implementation leads to small chip area. The output of ADC can be compressed into a much shorter addressing character in logarithmic law, in order to reduce the required memory size.