Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Gas Fraction Control System for a Gas Evolving Electrochemical Reactor Craig E. Nelson - Consultant Engineer

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Reactor Controller Functional Diagram Block Diagram for Bubbleostatic Operating Mode - Loop Dynamics Circuit Standby Current Source Set Point + Counter – Anode – Ec – Red Working – Cathode – Ew Blue-Green Cathodic (Negative) current Bubble Electric Eyes Sensor Support Circuit Parameter Extraction Circuit Voltage Controlled Power Supply Standby

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Reactor Control System Block Diagram Bubble Detector Support Circuit Signal Smoothing Circuit Parameter Extraction Circuit Loop Dynamics Circuit Voltage Controlled Current Source PID Loop Dynamics Photons V2V3V4V5 Iout Controller Set point V1 Parameter ExtractionDetection Standby Current Source I1 I2 Standby Det1 Det2 Current Drivers Power Supply

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com 1.Controller should provide at least a second order transfer function 2.Controller should provide easy adjustability of the transfer function dynamics Requirements - Loop Dynamics

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Loop Dynamics - The PID Controller

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Concept 1 – Absolute Amplitude Feedback Input scaling and offset Amplify Integrate Differentiate Output scaling and offset PID Dynamics Vin V4V5 Vout Set point V1

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Parameter Extraction 1.Accept signals from one or more concentration sensing sources 2.Pre-process the sensor signal as required 3.Extract various parameters from the concentration sensor as required 4.Scale and offset the parameter signals as required

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Typical Bubbleogram 512 Samples

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Typical Bubbleogram Descriptive Statistics

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Power Spectral Density

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com

Autocorrelation

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com

Current Noise Signal Analysis

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Current Noise Signal

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Current Noise Power Spectral Density

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Current Noise PSD

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Current Noise Autocorrelation Functions

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Current Noise Autocorrelation

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Cross Comparison – Bubbleogram vs. Current Noise - Waveforms

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Waveforms BubbleogramCurrent Noise

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Cross Comparison – Bubbleogram vs. Current Noise – Power Spectral Density

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Power Spectral Density BubbleogramCurrent Noise

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Cross Comparison – Bubbleogram vs. Current Noise – Autocorrelation

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Autocorrelation BubbleogramCurrent Noise

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com System Control Parameter Extraction - Amplitude

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Concept 1 – Absolute Amplitude Feedback Input scaling and offset Signal Smoothing Absolute Value Vin V2 Vout V1

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Concept 2 – Detrended Abs Amplitude Feedback Bubble Detector Variance Estimator + LP Filter Detrender Bubbles In V2 Vout V1 Boundary Alarm Generator Integrator V10V9 Integrator Preset Mean Estimator Cell Driver Vset V4 V3 V7 V5 V2 Median Filter V1 V2 = median(V1i … V1i+N) mean(V2i …V2i+N) Var(V2i …V2i+N) V6 BUset BLset V8 V5 = 1 if (V4 > BUset) V6 = 1 if (V4 < BLset) V7 = Pu if (V5 =1) V8 = Pl if (V6 =1) med(V2i …V2i+N)

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com The Median Filter

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Concept 2 – Bubble Rate Feedback Input scaling and offset Pulse Rate to Amplitude Converter Differentiator and Limiting Amplifier Vin V2 Vout V1

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Cell Driver – Block Diagram Input scaling Cell Driver Power Amplifier Standby Controller Vin V6Vout - Iout Standby Current Set point V1 Current Sensor V4V3 V2 V8 V7 Cell Driver Feedback Network DC Power V5 Standby Mode Select Current Monitor

Nelson Research, Inc – N. 88 th St. Seattle, WA USA aol.com Summary and Conclusions A system concept has been developed and presented A parameter extraction strategy has been presented These methods can be used to extract gas fraction information from gas bubble sensing devices