Integrační měření s aproximačním převodníkem

Článek se zabývá integrací měřených hodnot z aproximačního A/D převodníku. Pozornost je věnována útlumu superponovaného střídavého rušení - NMR.This paper solved data integration from aproximation A/D converters. Observation is dedicated to normal mode rejection - NMR

Přesnost analogově-digitálního převodníku v STM32 mikropočítačích

Článek analyzuje některé vlastnosti analogově-digitálního převodníku zabudovaného v mikropočítači řady STM32F100. Pozornost je věnována zabudovanému referenčnímu zdroji, snímači teploty čipu, linearitě a šumu převodníku.This paper analyses some features of an analog to digital converter embedded to STM32F100 microcontrolers. Observation is dedicated to embedded reference voltage, temperature sensor, linearity and noise of converter

Experimental Electric Power System for Small Satellites with Independent Supply Channels

Small satellites such as CubeSats are not adequately protected in the cosmic environment from ionizing radiation due to the low weight limit, which does not allow the use of heavy shielding materials with the high atomic number. Therefore, the power supply system of such small satellites must be protected from radiation induced failures in the satellite electronic subsystems. The power supply system must also provide a reliable power supply in the event of a fault in its own components. This requires more independent power supply channels for satellite subsystems and reliable protection circuits. In this paper, we propose an electric power system with three independent channels and necessary protection circuits for the PilsenCube II satellite. Two supply channels use Li-Ion accumulators and unregulated bus. The third supply channel uses supercapacitors and regulated bus. The three independent supply channels are complemented by the overcurrent protection circuits in each subsystem board that allow controlled post-fault regeneration

Communication Subsystem for PilsenCUBE Nanosatellite

This paper presents a design concept of new radio communication subsystem, intended for use on the PilsenCUBE nanosatellite. The hardware and software solution is based on previous experiences with the VZLUSAT-1 setup and operation. Our aim is to overcome weak points which were found, use modern powerful components actually available and build reliable radio for nanosatellite use. For better reliability, radiation tested components were used on critical place and complex system for diagnostics and fault protection was designed and implemented. The satellite radio communication protocol was also modified to comply with all requirements of nanosatellite operation. Satellite control data has to be secure, but significant part of experimen data need to be widely available to all ground segments on the World. This also improves the communication link capacity and reliability

PilsenCUBE-II Measurement Board as interface for student’s experiments

One of the main goals of the PilsenCUBE-II picosatellite project is to offer on board payload space for the student's experiments for the students from the various secondary schools of the western Bohemia. The students experiments have to be simple enough in scope of skills and abilities of the secondary schools students but should provide interesting results for satellite project. There is 6 student's experiments in the second round of competition. This experiments will be integrated into satellite as a parts of the measurement board (MES). The measurement board will provide the interface between these student's experiments (STE) and On-Board Computer (OBC) that is controlling the functions of the satellite and providing the communication with ground station

Partial discharges pulse shape analysis at AC and DC

Partial discharge (PD) signal analysis is a well-known tool for monitoring the conditions of insulation systems of electrical machines and equipment. Classical analyzes of PD are mostly based on the eval- uation of the phase angle of the test voltage at which partial discharges occur. At the present, the partial discharge detection is mostly based on the measurement of charging currents that are needed to resume the volt- age on the sample that was there before the partial discharge occurred. Other electrical methods are, for example, the scanning of an electromagnetic field emitted during a partial discharge. Another developed methodology in the field of measuring and analyzing partial discharges is the monitoring of pulse parameters of the detected discharge. Experiments suggest that measuring the rise and fall time of the pulse edges and amplitude measurements can evaluate the partial discharge signal. Especially this method could be very helpful at the moment when partial discharges at DC are studied and evaluated. The disadvantage of partial discharges at DC is the fact there is no phase and phase angle position for PD patterns recognition. Thus, another evaluation method development is necessary for PD recognition DC. There is presented in the study an experiment where the PD pulse shapes, in the manner of rise time and fall time, were investigated at laboratory PD models at both voltage types AC and DC. The PD models simulated corona discharges. Each individual pulse of a partial discharge can be detected by a suitable scanning impedance and viewed with fast digital oscilloscopes. As has been said, there is a presumption that different discharge arrangements or even variously degraded insulating materials have different waveforms of the sensed pulses. The main monitored parameters of individual pulses are their rise time and amplitude. Since the occurrence of partial discharge is essentially a random phenomenon, statistical analysis of a significant amount of data is required. A view of the behaviour of the partial discharge pulse in various cases of the discharge activity brings different results in the observation of the pulse rise time and its amplitude in the various observed setups. Monitoring the rise time and pulse amplitude is one way of evaluating partial discharges, regardless of their superimposed position on the sine wave of the supply voltage. Thus this PD monitoring could be a part of PD evaluation at DC. These pulse parameters together with other PD analysis at DC (as pulse sequence analysis) could be used to estimate the partial discharge type as well as to evaluate the deterioration of the insulation of electrical machines

Design of current sensor for medium frequency operation

The paper proposes design procedure of several types of current sensors. The winding design is analyzed regarding its impact on operational characteristics and evaluated for preferred application. The paper also discusses the measurement results and given frequency characteristic and quality factors of the laboratory prototypes

Intelligent high current sensor for various frequency

The paper proposes a design procedure of a current sensor. The winding design is analyzed regarding its impact on the operational characteristics and is evaluated for a preferred application. The paper also discusses the measurement results and given frequency characteristic and quality factors of the laboratory prototypes. The sensor is designed for a current up to 200 A and frequency up to 120 kHz. The sensor is equipped with an electronic unit in a common housing. The electronic transducer evaluated the measured data and produces the digital output signals which is easy to transfer even to a long distance