The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The article describes using of power semiconductor converters in the area of accumulation of electrical energy in the Technology Centre Ostrava (TCO). Further discloses design of the power semiconductor converters, its internal structure, utilization of energy and the main parameters and focuses on the issues of the capacitor bank — determine the power loss of capacitors, determine the lifetime, determination...
The simple and fast liquid inspection method using step response in electromagnetic sensor is presented. When the liquid sample is set inside the cylindrical electromagnetic sensor, the impedance profile of the sensor changes in accordance with the electromagnetic properties of the liquid. First of all, the theoretical background is explained with a simple RLC circuit analysis. To provide a simple...
This paper introduces the design of a Marx Generator that can generate high attitude pulses up to 25 kV and 2.5 kA. The pulses have a wave shape representative of that used to test High-altitude ElectroMagnetic (HEMP) filters against the pulse current injection (PCI) requirements. The rise time is 20 ns and the pulse width is 230 ns on a 10 Ω resistor. In the design, it was found that parasitic effect...
The traditional boost PFC converter in critical conduction mode (CRM) usually suffers from low power factor (PF) in high input voltage and light load conditions due to the influence of the differential mode (DM) capacitor. With the capacitive current flowing into the DM capacitor, the input current has an evident leading phase and a period of dead time in these conditions. In order to solve this problem,...
Two examples and a programming strategy are used to further illustrate the principles of the new estimate method introduced in part I of the paper. In two examples, soft-faults of some elements are simulated, and steady-state node-voltage vectors (SSNVVs) are measured. Then the new estimate method is carried out. Results show the proposed method would effectively improve estimate process of a soft-fault...
Rapid capacitor chargers are typically used to charge a bank of capacitors with the purpose of discharging it into a pulsed power load [1,3]. Previous research shows that the charging voltage of the load can be accurately calculated in real-time using microcontroller software algorithms [1,5]. The objective of this paper is to report a hardware based approach to measure the charge transfer into the...
Electrical equipment like motion detectors, time switches, presence sensors, timers, low power LED lamps or LED night lights have real power less than 1 Watt at the AC grid 230V/50Hz. But if we analyze the circuit topology, there are many conventional resistors to limit the inrush current. With an inrush controller with switched transistor we can eliminate the resistors and improve the efficiency.
Capacitance and tan δ measurements are usually carried out to check the healthiness of an insulation. Measuring equipment based on different methodologies to test insulation in cables, transformer bushings etc. are available. This paper presents the development of such a measuring equipment for a high voltage (HV) laboratory of a University. The design is divided into three parts as filter unit, test...
This work presents a driver for High-Brightness Light-Emitting Diodes (HB-LED) in three-phase grids, which complies with IEC 1000-3-2 Class C requirements, achieves high Power Factor (PF), low Total Harmonic Distortion (THD), as well as, the capability to achieve full dimming while disposing of the bulk capacitor and having galvanic isolation. The HB-LED driver is based on the use of six four-port...
A robust dc-link voltage control using virtual resistor will be presented in this paper. Virtual resistor will be used to generate correction factor for power balance control method in dc-link voltage control. With this control method, dc-link voltage can be maintained in stable condition and operated on desired safe voltage range. The proposed control method is using simple mathematics equation to...
This paper presents results of impedance measurements of low-voltage (230 VAC) electrical grid at the wall socket. The measurements were performed in context of Power-Line Communication (PLC) in urban and suburban areas. There have been measured complex impedance (magnitude and phase) in 10 kHz – 1 MHz frequency range, covering CENELEC, ARIB and FCC bands. The measurements were performed using low-cost...
In microgrid systems one or more inverters should be grid-forming in order to control the voltage during island mode operation. Usually the voltage regulation is operated controlling the capacitor voltage of the LCL filter interconnected between the converter and the load. In the present paper a cascade control is proposed for a Three-Level Neutral Point Clamped (3L-NPC) inverter where the voltage...
Voltage-to-time converter (VTC) circuits are used as the core component of single-slope analog to digital converters (ADCs). These VTC circuits have traditionally depended on the use of a constant current source as part of their implementation in order to have good linearity. An alternative approach is presented where only voltage sources and a few discrete components are needed without sacrificing...
A wide input range 1.7μW, 1.2kS/s resistive sensor interface circuit fabricated in 0.18μm CMOS is presented. This circuit consumes 6.6× lower power and 31.8× less energy than previous state-of-the-art work, considering the worst-case cycle count required for correct conversion. The proposed design uses a logarithmic subrange detector based on comparator metastability to convert an input resistance...
The problem of pulse voltage measurements in the nanoseconds range has become of great importance with ongoing problems related to the construction of pulse fusion generators as well as with simulations of electromagnetic pulses related to the atmospheric nuclear explosion. Ultrafast pulses in the nanoseconds range can be measured by the capacitive voltage divider. The problem that arises with ultrafast...
Experimental results of a fully integrated low ripple charge pump voltage converter are presented. The pump is a current mode voltage doubler with a novel parasitic capacitance precharge mechanism for output voltage ripple reduction. A prototype of the pump was designed and fabricated in 130 nm CMOS process. The pump supplied with 1.2 V delivers 1.5 V on its output. Despite reducing the size of the...
This paper presents a broad overview of impulse voltage generator; it consists of multi stage impulse voltage generator design and its simulation and different experimental analysis. This paper gives design of 90 KV, 1.2/50 μs impulse high voltage wave generation.
This paper describes a digital alternating current (ac) quadrature bridge for impedance measurements under development at INMETRO. This bridge is primarily intended to allow the comparison of ac resistors with standard capacitors but it could be applied to a myriad of impedance-measurement tasks as the precise determination of dissipation factor of capacitors, of resistor time-constants, as well as...
This paper describes two methods of electric charge calibration, one based on capacitors and a voltage source, another in a commercial current source. They were compared, and good agreement was found. Strengths and weakness of the two methods are remarked.
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.