Control system for an electrolytic cell

Patent metadata

Field	Value
Publication number	US-10161053-B2
Application number	US-201514951582-A
Country	US
Kind code	B2
Filing date	Nov 25, 2015
Priority date	May 6, 2015
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

A control system for an electrolytic cell includes a voltage converter converting an input voltage into a decomposition voltage, a temperature sensor generating a sensed temperature, an electric power sensor generating a sensed voltage, and a control unit storing voltage-temperature characteristics. The control unit determines a voltage that corresponds to the sensed temperature according to one of the voltage-temperature characteristics, and generates, according to a difference between the voltage thus determined and the sensed voltage, a control signal which is provided to the voltage converter such that the decomposition voltage decreases along with increase in the sensed temperature.

First claim

What is claimed is:

1. A control system for an electrolytic cell, the electrolytic cell containing an electrolyte for carrying out electrolysis of the electrolyte when a decomposition voltage is applied thereto, the control system comprising:
a voltage converter to be coupled electrically to the electrolytic cell, receiving a control signal and an input voltage, and converting, according to the control signal, the input voltage into the decomposition voltage which is to be provided to the electrolytic cell;
a temperature sensor sensing a temperature of the electrolytic cell to generate a sensed temperature;
an electric power sensor to be coupled electrically to the electrolytic cell, and measuring a decomposition current flowing through the electrolytic cell to generate a sensed electric current; and
a control unit coupled electrically to said voltage converter, said temperature sensor for receiving the sensed temperature and said electric power sensor for receiving the sensed electric current, and including a characteristic library, said characteristic library storing a plurality of voltage-temperature characteristics each of which corresponds to a respective electric current and records different temperatures and corresponding voltages, and storing a plurality of first impedance-temperature characteristics each of which corresponds to a respective electric current and records different temperatures and corresponding electrical impedances, where the temperature is negatively correlated to the voltage, and negatively correlated to the electrical impedance;
wherein when receiving an instruction signal which assigns a designated current at which the electrolytic cell operates, said control unit determines one of the voltages that corresponds to the sensed temperature according to one of the voltage-temperature characteristics corresponding to the designated current, determines one of the electrical impedances that corresponds to the sensed temperature according to one of the first impedance-temperature characteristics corresponding to the designated current, calculates the decomposition voltage corresponding to the sensed electric current according to the sensed electric current and said one of the electrical impedances thus determined, and generates, according to a difference between said one of the voltages thus determined and the decomposition voltage thus calculated, the control signal which is provided to said voltage converter such that the decomposition voltage decreases along with increase in the sensed temperature.

2. The control system according to claim 1 , wherein said characteristic library further stores a plurality of current-temperature characteristics each of which corresponds to a respective voltage and records different temperatures and corresponding electric currents, and stores a plurality of second impedance-temperature characteristics each of which corresponds to a respective voltage and records different temperatures and corresponding electrical impedances, where the temperature is positively correlated to the electric current, and negatively correlated to the electrical impedance; and when receiving an instruction signal which assigns a designated voltage and a limiting current at which the electrolytic cell operates, said control unit determines one of the electrical impedances that corresponds to the sensed temperature according to one of the second impedance-temperature characteristics corresponding to the designated voltage, calculates the decomposition voltage corresponding to the sensed electric current according to the sensed electric current and said one of the electrical impedances thus determined, and generates, according to a difference between the designated voltage and the decomposition voltage thus calculated, the control signal which is provided to said voltage converter such that the decomposition voltage is maintained at the designated voltage until the sensed electric current is equal to the limiting current.

3. The control system according to claim 1 , wherein said control unit further includes:
a voltage conversion table recording a plurality of voltage differences and corresponding control parameters; and
a processor coupled electrically to said voltage converter, said characteristic library and said voltage conversion table, coupled electrically to said temperature sensor for receiving the sensed temperature, and coupled electrically to said electric power sensor for receiving the sensed electric current, said processor receiving the instruction signal, determining said one of the voltage-temperature characteristics that corresponds to the designated current in said characteristic library according to the instruction signal, determining said one of the voltages that corresponds to the sensed temperature according to said one of the voltage-temperature characteristics thus determined and the sensed temperature, calculating the decomposition voltage corresponding to the sensed electric current according to the sensed electric current and said one of the electrical impedances thus determined, and determining one of the voltage differences that is identical to the difference between said one of the voltages thus determined and the decomposition voltage thus calculated according to the voltage conversion table, so as to generate the control signal according to one of the control parameters corresponding to said one of the voltage differences in the voltage conversion table.

4. The control system according to claim 1 , further comprising a cooling unit to be coupled to the electrolytic cell and coupled electrically to said control unit, said control unit storing a limiting temperature, wherein when the sensed temperature received from said temperature sensor is greater than the limiting temperature thus stored, said control unit generates an activation signal to be outputted to said cooling unit such that said cooling unit is activated to reduce the temperature of the electrolytic cell.

5. The control system according to claim 1 , further comprising a flow measurement unit to be coupled to the electrolytic cell and coupled electrically to said control unit, said flow measurement unit measuring a flow rate of a gas generated by the electrolytic cell to generate a measured flow rate which is provided to said control unit.

6. The control system according to claim 5 , further comprising an input and display unit coupled electrically to said control unit, said input and display unit being operable to generate the instruction signal according to user input of an input command, said control unit converting the sensed temperature, the sensed electric current, the measured flow rate, and said one of the voltages that corresponds to the sensed temperature into a display signal which is to be provided to said input and display unit for display thereon.

7. The control system according to claim 1 , wherein each of the voltage-temperature characteristics stored in said characteristic library includes plural entries of relationships between the different temperatures and the corresponding voltages, said control unit determining a corresponding one of the voltages in a manner of referring to a lookup table.

8. The control system according to claim 1 , wherein each of the voltage-temperature characteristics stored in said characteristic library includes a predetermined approximate function of a curve which is associated with the different temperatures and the corresponding voltages, said control unit determining a corresponding one of the voltages in a manner of inputting the sensed temperature into the approximate function.

Assignees

• Univ National Chiao Tung

Inventors

• Chiou Jin-Chern
• Chang Pao-Yuan
• Huang Yu-Chieh
• Wu Chin-Cheng
• CHANG Huang-Yuan

Classifications

• C25B1/04 Primary

  by electrolysis of water · CPC title

• C25B15/02 Primary

  Process control or regulation · CPC title

• Y02E60/366

  Cross-Sectional Technologies · mapped topic

• C25B15/021

  of heating or cooling · CPC title

• Y02E60/36

  Hydrogen production from non-carbon containing sources, e.g. by water electrolysis · CPC title