Valentin Sita

Measured signal identification and temperature controller design for a HIPEC device

Peritoneal Carcinomatosis (PC) is an abdominal cancer for which cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC) proved to be a promising treatment. HIPEC requires the intraperitoneal spread of cytostatic solution at high temperatures (41-43°C) accomplished within 60-120 minutes, during surgical interventions. This paper presents the heating systems identification, by using a graphical fitting method on a temperature measured signal, for a HIPEC device intended to be developed. Also the design of two PID temperature controllers is presented, using the Strejc design method and the Ziegler-Nichols method. The two feedback control structures are compared via simulation, based on their step response signals and their overall performances.

Rapid Control Prototyping toolbox for Renesas M32C87 microcontroller

The paper presents a Rapid Control Prototyping (RCP) toolbox for Matlab/Simulink, which can be used to generate real-time C code for the Renesas M32C87 microcontroller. The toolbox, Target for Renesas M32C87, contains Simulink blocks, which implement drivers and algorithms specific for the M32C87 processor, grouped in four libraries: I/O drivers, Digital Motor Control (DMC), Controller Area Network (CAN) and Serial Communication Interface (SCI). Control algorithms, for the M32C87 microcontroller can be developed using blocks from the Target for Renesas M32C87 toolbox and predefined blocks from Simulink or user defined blocks. After the validation of the model the cod generation process can be invoked. At the end of the code generation process the High-performance Embedded Workshop (HEW) Integrated Development Environment (IDE) is automatically started, a new HEW project is created, the generated code-source files are added to the project, the project is compiled and the binary file is downloaded to the target processor. The execution of the code can be monitored in real-time using the implemented CAN drivers.

Heating efficiency with multiple boilers. Case study for single, two and three boiler operation

Building energy consumption counts for almost a third of the global energy consumption and most of that is used for building heating and cooling. A comparative study was performed on heating systems regarding the number of cascading boilers and the influence on heating efficiency. Results indicate a 15% increase in efficiency in case of multiple boiler systems compared to single boiler installations.

Real Power and Frequency Control – Case Study for a Synchronous Generator from the Structure of a Hydroelectric Power Plant

This paper presents a solution for the real power control, generated by a synchronous generator belonging to a small hydroelectric power plant. The proposed control system is based on the simple feedback structure which contains also, a frequency correction loop. The mathematical models of all the elements from the control structure are detailed. Also, starting from these models, the real power controller (of Proportional – Integral – Derivative type) tuning procedure is presented. In the end of the paper, the simulations results of the control system are presented highlighting the obtained control performances. The proposed solution is a general one and it can be adapted with relative minor changes to any hydroelectric power plant.

Neural Modeling and Control of a 13C Isotope Separation Process

The paper presents a solution for the 13C isotope concentration control inside and at the output of a separation column, solution based on the Internal Model Control strategy. The 13C isotope results from a chemical exchange process carbon dioxide - carbamate, which is a distributed parameter process. In order to model the mentioned process, an original form of the approximating analytical solution which describes the process work in transitory regime is determined. The evolution of the approximating solution depends both on time and on the position from the column height. The reference model of the fixed part of the control structure is implemented using neural networks, representing an original solution due to the fact that a neural model is determined for a distributed parameter process. The controller is, also, implemented using neural networks, its main parameter being adapted in relation to the transducer position change in the separation column. The advantages of using the proposed concentration control strategy consist of: the possibility of controlling the value of the 13C isotope concentration in any point from the separation column height; the improvement of the system performance regarding the settling time; the possibility to reject the effect of the disturbances.

Model based fault detection for electrical drives with BLDC motor

Continuous improvements in microelectronic circuitry make possible the implementation of process diagnostics to a variety of systems in order to increase performances and reliability. The monitoring stage in the area of failure detection and isolation aims to classify and arrange the failure sources. In case of BLDC machines, one of the most important methods for failure detection and diagnosis starts with the analysis of the variations of the machine estimated parameters. The paper focuses on the implementation details of failure detection and diagnosis based on continuous time parameters estimation of BLDC motor mathematical model. Continuous time parameters are directly related to the physical characterizations of BLDC Motor. The parameters are estimated by the well-known prediction error methods devised for dynamic system identification. By changing the process coefficients and by applying statistical decision methods, failure detection occurs. The case of frequency domain identification in fail detection is also covered on a real CNC machine. Discrete Fourier Transform (DFT) with the particular case of Goertzel algorithms is implemented for fault detection purposes. Unlike existing work and results in the fault detection area, the failure can be detected among time-varying process parameters.

Energy Efficient Design and Control for PEM Water Electrolyzer and Hydrogen Storage System

Abstract This paper presents a design and control method for increasing the efficiency of the hydrogen storage systems with PEM water electrolyzers. Suitable pressures for later feed to fuel cell stack are achieved without the need of compressors and pumps are required only for reduced time.