Converter for starting motor-generator sets of autonomous locomotives

Objective: To confirm the possibility of using a starting converter to spin up the shaft of the motorgenerator set to a speed that ensures stable combustion of the air-fuel mixture in the motor cylinders (starting), as well as of using semiconductor converters based on modern IGBT modules for starting promising motor-generator sets of mainline and shunting locomotives. Methods: The properties, characteristics, and operating modes of starting converters were studied on test benches. Results: The downsides of the currently most commonly used starter-generator circuit for engine starting have been identified. A technical solution has been developed to replace the startergenerator circuit with an inverter starting system using a starting converter for starting the locomotive motor-generator. The device structure has been designed. The basic algorithms of the automatic control system of the starting converter have been implemented. Bench tests of a starting converter prototype have been carried out. Practical importance: The developed technical solution in terms of replacing the starter-generator circuit with an inverter starting system for starting the motorgenerator set of autonomous locomotives makes it possible to increase their reliability by removing the electromechanical drive and replacing a number of engine drive auxiliary camshaft mechanisms (group 69). The inverter starting system will reduce the maintenance and scheduled repair costs, decrease the labor input, and optimize the time-schedule of locomotives. The proposed algorithms for starting the motor-generator set enable increasing the battery life by limiting its starting current, as well as improving the fault tolerance of a locomotive due to the possibility of starting the motorgenerator set at a low battery voltage (lower limit of 45 V).

Low-cost laser diode pulse generator for quantum information applications

A simple short-pulse generator circuit based on electronic gates is designed for short electric pulse of about 12 ns at Full Width at Half Maximum (FWHM) and 3.6 Volt amplitude for driving a laser diode. Using our circuit with a 780 nm laser diode designed and fabricated for producing short light pulses. The circuit utilizes an AND gate, a XOR gate, and a common function generator, provides a repetition rate from DC up to 1 MHz. The laser pulses were generated and then detected via an avalanche photodiodes (APD). This finding can benefit the field of light-based quantum information including single photon experiments.

Macro-Modeling for N-Type Feedback Field-Effect Transistor for Circuit Simulation

In this study, we propose an improved macro-model of an N-type feedback field-effect transistor (NFBFET) and compare it with a previous macro-model for circuit simulation. The macro-model of the NFBFET is configured into two parts. One is a charge integrator circuit and the other is a current generator circuit. The charge integrator circuit consisted of one N-type metal-oxide-semiconductor field-effect transistor (NMOSFET), one capacitor, and one resistor. This circuit implements the charging characteristics of NFBFET, which occur in the channel region. For the previous model, the current generator circuit consisted of one ideal switch and one resistor. The previous current generator circuit could implement IDS-VGS characteristics but could not accurately implement IDS-VDS characteristics. To solve this problem, we connected a physics-based diode model with an ideal switch in series to the current generator circuit. The parameters of the NMOSFET and diode used in this proposed model were fitted from TCAD data of the NFBFET, divided into two parts. The proposed model implements not only the IDS-VGS characteristics but also the IDS-VDS characteristics. A hybrid inverter and an integrate and fire (I&F) circuit for a spiking neural network, which consisted of NMOSFETs and an NFBFET, were simulated using the circuit simulator to verify a validation of the proposed NFBFET macro-model.

Experimental Study on Micro-Grinding of Ceramics for Micro-Structuring

In this study, micro-grinding was performed to investigate the machining characteristics of alumina and zirconia. The machining of ceramics remains highly challenging owing to their properties, such as high brittleness and wear resistance, which leads to a shorter tool life and high machining costs. Polycrystalline diamond (PCD) was selected as the tool material, as it is suitable for machining hard and brittle materials, and micro-electrical discharge machining (EDM) was used to fabricate PCD micro-tools. When using a resistor-capacitor generator circuit in micro-EDM, the discharging energy is related to the working capacitance, and by controlling the working capacitance, the different edge radii and the surface roughness of the tool can be easily achieved. The feed rate, depth of cut, and rotation speed were set as experimental parameters to investigate the grinding characteristics of the ceramics. During the experiment, the grinding force and roughness of the bottom surface were monitored, and the roughness of the machined surfaces was measured using a three-dimensional surface profiler. A working capacitance of 1000 pF was used to fabricate a tool with an edge radius of 3.5 µm. The lower radius of the tool edge resulted in a decrease of the cutting force by 50% at most and a surface roughness of 19 nm Ra.

Cost-Effective Design of Amplifiers for Hearing Aides Using Nullors for Response Matching

This chapter starts reviewing Fixator-Norator Pairs (FNP) as an effective tool used to design analog amplifiers for a prescribed bandwidth and frequency profile. Among number of cases and applications, designing for hearing aides are particularly important, where the hearing frequency profiles, known as audiograms, are changing from person to person, and also for a person by the age. The design is mainly focused on front-end or stand-alone amplifiers. In case of a front-end the response from the amplifier can be digitized, properly controlled and adjusted to fit the digital application. Here is how the design proceed. For a given audiogram, an Audiogram Generator Circuit (AGC) is initially constructed. This AGC, usually a complete passive circuit, produces a frequency response that closely matches with the audiogram, obtained from a hearing impaired patient. The AGC is then embedded in an amplifier circuit where a fixator is placed at its output port, “forcing” the amplifier to generate the desired output frequency response profile. A flat band frequency response, for example, compensates the hearing losses and provides a uniform hearing to the patient in the entire audio bandwidth. The amplifier can be further enhanced to perform other requirements, for example, to cancel undesirable noises in certain frequencies or to magnify the voice in critical frequencies for clarity. Another alternative design methodology is also introduced in this chapter, which uses the negative feedback technique.

ANALISA CLOCK GENERATOR PADA RANGKAIAN POWER SUPPLY UNTUK APLIKASI TRIGER IC TTL DILABORATORIUM DIGITAL PROGRAM STUDI TEKNIK ELEKTRONIKA DI POLITEKNIK NEGERI MALANG

The good performance of a clock generator circuit in the power supply for triger TTL IC is very influential on the success of the lab. A series. Therefore, the effectiveness of use must be adapted to its use in the practicum. To create a clock generator circuit as a source of pulses from a digital counter IC, a timer IC can be used. This pulse generator or clock generator can be used for clock sources in making counters up and down. Clock generators are often referred to as clock generators. The pulse generator in making the circuit is often used linear integrated circuit (IC: Integrated Circuit). A linear IC that is commonly used in general is usually the NE555 which is a timer IC. As a timer it can also be used analogically as a Clock Generator or pulse generator which can generally generate the frequency or time as needed.

Design of 4-stage Marx generator using gas discharge tube

In this paper, a Marx generator voltage multiplier as an impulse generator made of multi-stage resistors and capacitors to generate a high voltage is proposed. In order to generate a high voltage pulse, a number of capacitors are connected in parallel to charge up during on time and then in series to generate higher voltage during off period. In this research, a 6kV Marx generator voltage multiplier is designed using gas discharge tube (GDT) as an electronic switch to breakdown voltage. The Marx generator circuit is designed to charge the storage capacitor for high impulse voltage and current generator applications. According to IEC 61000-4-5 class 4 standards, the storage capacitor must be charged up to 4 kV. The results show that the proposed Marx generator can produce voltages up to 6.8 kV. However, the storage capacitor could be charged up to 1 kV, instead of 4 kV in the standard. That is because the output impulse voltage has narrow time period.