The paper develops and compares intelligent sensors for flux and torque estimation in permanent magnet synchronous motors (PMSM) based on combined voltage-current flux estimators and interpolating implementation. Typical applications are in the direct torque and flux control (DTFC) and in the field-oriented vector control of ac drives. Simulation results using a PMSM drive system prove good dynamic performances of the flux and torque sensors to parameter deviations in wide speed range.
A communication interface card with intelligent feature is described. It can be widely used in distributed system. Taking the advantage of isolation and dual-CPU technology, the card makes station identification and network data analysis easier and more intelligent, and improves the situation of code leakage that may occur during practical application.
This paper discusses the design and implementation of a new industrial water level measurement and control system. Virtual Instrument technology is employed to construct the software and hardware framework. The modularized system features high flexibility and expandability. The system provides with parameter display, data testing, alarming, storage and printing. The system is opening and compatible.
In this paper, a SCADA system of chemistry in the power-plant is brought forward with the functions of intelligent instrument, cybernation and information sharing, which is an effective solution to preventing for filthy, erosion and burst of the pipes in the critical and sub-critical boiler system. More over, it is one of the critical ways of increasing the efficiency of the turbine and decreasing the consumption of coal.
The paper describes construction and technical parameters of the low-distortion Wien type oscillator determined for dynamic testing of high resolution ADCs in frequency range up to 2 MHz.
Measurement can be used throughout a software project to assist in estimation, quality control and project control. Software measurement is concerned with capturing information about attributes of entities. Cost estimation models are developed using data from completed software projects and accuracy tests are usually done using data sets with known project size. Software metrics provide a quantitative way to assess the quality of internal attributes. This paper will focus on ways and methods to measure the software system.
In the framework of laboratory exercises for students attending lectures on metrology of electrical quantities at the Faculty of Electrical Engineering, Czech Technical University, application of inductive voltage dividers to precision coaxial bridges is demonstrated. Four terminal-pair bridges are used in comparisons of like impedances and a quadrature bridge has been realized for linking resistance and capacitance standards. A method for calibrating multi-decade inductive voltage dividers has also been developed.
A pulse width modulated analogue-to-digital converter (ADC) that provides a low-cost solution for lowspeed applications is described. The proposed solution also provides automatic range selection and continuous auto-calibration capabilities. Simulation and experimental results are used to confirm the theoretical expectations of this ADC well adapted to strongly non-linear transducer interfacing.
In the paper the Zero-Crossing-Sequence Shape method is described. The method effectively classifies the M-ary PSK and M-ary FSK modulated signals detecting both the phase and frequency shifts in the incoming signal by using the zero-crossing and instantaneous frequency variation sequences. Moreover, from these sequences, independently from the modulation classification, the Carrier-to-Noise-Ratio (CNR), the carrier frequency and the symbol rate are also determined. In order to make the method able to operate at lower CNR, preprocessing of the instantaneous frequency sequence and statistic...
This Paper gives a summary of a completely automated system that was developed for the high accuracy calibration of multifunction measuring instruments (like the Fluke 5720A calibrator or HP3458A multimeter, for example). The system is capable of calibrating all the functions (ranges: Vdc: 10 mV... 1 kV; Vac: 2 mV... 1 kV; Idc: 10 µA... 2 A; Iac: 10 µA... 2 A) of digital calibrators and multimeters at very high accuracy. Additionally, efficiency and facility of operation are characterizing the system, which became a powerful tool in electrical metrology.