The Quantitative Forecast and Suppression on the Electromagnetic Radiation from Low Voltage Frequency Converter

2014 ◽  
Vol 575 ◽  
pp. 696-703
Author(s):  
Cheng Hai Gao ◽  
Jian Ru Wan ◽  
Jiang Li
Keyword(s):  
Electromagnetic Radiation ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Frequency Converter ◽  
International Standards ◽  
Value Change ◽  
Radiation Characteristics ◽  
Radiation Theory ◽  
Voltage Frequency ◽  
The Impact

The main electromagnetic radiation source and the generating mechanism in low voltage frequency converter were defined and analyzed in this paper according to electromagnetic radiation theory together with the discussion of the impact on radiation from raise time, falling time of pulse width modulation (PWM) signal and carrier frequency, so that the radiation can be understood more exactly in term of numerical value change, which helps specifically reduction of converter radiation during design phase in compliance with related international standards and technical norms regarding industrial converter. Started with the theory of electromagnetic field the zone around converter were differentiated and analyzed based on the radiation characteristics. As main means of radiation suppression in converter shielding and grounding were quantitatively analyzed. A series of tests with different power rating converters verified the calculation and analysis. Consequently the design of converter was guided to meet the requirements of standard.

scholarly journals Implementation and Experimental Verification of Smart Junction Box for Low-Voltage Automotive Electronics in Electric Vehicles

2020 ◽  
Vol 10 (7) ◽  
pp. 2214
Author(s):  
Sang Wook Lee ◽  
Soo-Whang Baek
Keyword(s):  
Electric Vehicles ◽  
Printed Circuit Board ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Short Circuit ◽  
Circuit Board ◽  
Area Network ◽  
Automotive Electronics ◽  
Overload Protection ◽  
The Impact

In this study, we designed and implemented a smart junction box (SJB) that was optimized for supplying power to low-voltage headlights (13.5 V) in electric vehicles. The design incorporated a number of automotive semiconductor devices, and components were placed in a high-density arrangement to reduce the overall size of the final design. The heat generated by the SJB was efficiently managed to mount an Intelligent Power Switch (IPS), which was used to power the headlights onto the printed circuit board (PCB) to minimize the impact on other components. The SJB was designed to provide power to the headlights via pulse width modulation to extend their lifetime. In addition, overload protection and fail/safe functions were implemented in the software to improve the stability of the system, and a controller area network (CAN) bus was provided for communications with various components in the SJB as well as with external controllers. The performance of the SJB was validated via a load operation test to assess the short circuit and overload protection functions, and the output duty cycle was evaluated across a range of input voltages to ensure proper operation. Based on our results, the power supplied to the headlights was found to be uniform and stable.

scholarly journals Dynamic and Static Calibration of Ultra-Low-Voltage, Digital-Based Operational Transconductance Amplifiers

Electronics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 983 ◽  
Author(s):  
Pedro Toledo ◽  
Paolo Crovetti ◽  
Hamilton Klimach ◽  
Sergio Bampi
Keyword(s):  
Pulse Width Modulation ◽  
Low Voltage ◽  
Process Variations ◽  
Pulse Modulation ◽  
Silicon Area ◽  
Operational Transconductance Amplifiers ◽  
Static Calibration ◽  
Digital Pulse ◽  
Transconductance Amplifiers ◽  
The Impact

The calibration of the effects of process variations and device mismatch in Ultra Low Voltage (ULV) Digital-Based Operational Transconductance Amplifiers (DB-OTAs) is addressed in this paper. For this purpose, two dynamic calibration techniques, intended to dynamically vary the effective strength of critical gates by different modulation strategies, i.e., Digital Pulse Width Modulation (DPWM) and Dyadic Digital Pulse Modulation (DDPM), are explored and compared to classic static calibration. The effectiveness of the calibration approaches as a mean to recover acceptable performance in non-functional samples is verified by Monte-Carlo (MC) post-layout simulations performed on a 300 mV power supply, nW-power DB-OTA in 180 nm CMOS. Based on the same MC post-layout simulations, the impact of each calibration strategy on silicon area, power consumption, and OTA performance is discussed.

scholarly journals Analysis and design of single phase voltage-frequency converter with optimized PI controller

2019 ◽  
Vol 10 (1) ◽  
pp. 522
Author(s):  
M. Asna ◽  
H. Shareef ◽  
S.N. Khalid ◽  
A. Al Dosari ◽  
B. Hamad ◽  
...  
Keyword(s):  
Low Voltage ◽  
Search Algorithm ◽  
Frequency Converter ◽  
Reference Value ◽  
Input Voltage ◽  
Voltage Regulation ◽  
Pi Controller ◽  
Analysis And Design ◽  
Frequency Detection ◽  
Voltage Frequency

This paper proposes a new voltage frequency converter (VFC) that converts both voltage and frequency to the required level of voltage and frequency in low voltage networks used in various countries. The proposed converter could be used as a universal power supply for sensitive AC loads. The converter is composed of, input voltage and frequency detection circuitry, full bridge boost rectifier and a DC to AC inverter. In addition, to improve the feasibility and performance of the converter, synchronous reference based PI (SRFPI) controller is adopted, where the system behaves similar to a DC-DC converter. The parameter selection of PI controller is done using a recent optimisation technique called Lightning Search Algorithm (LSA). The simulation of VFC is conducted in MATLAB/Simulink environment. The simulation results shows that LSA based PI controller provides better output voltage regulation with respect to the reference value under various load and input conditions.

scholarly journals Justification of the Harmonics Active Filter Circuit Based on a Hybrid Cascade Inverter

2021 ◽  
Vol 21 (2) ◽  
pp. 105-114
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Block Diagram ◽  
Nonlinear Load ◽  
Higher Harmonics ◽  
Semiconductor Switches ◽  
Harmonic Filter ◽  
The Impact ◽  
Cascade Inverter

With an increase in the number of levels in the inverter, the circuit becomes more complicated, the number of semiconductor switches increases. Therefore, topologies, which make it possible to obtain an increase in voltage levels with a decrease in the number of semiconductors, to increase the performance and reliability of the system, are of great interest. The paper proposes a scheme of a hybrid cascade inverter, considers a method of pulse-width modulation based on a carrier, and presents a block diagram of an algorithm for generating reference modulating signals in an optimized method of pulse-width modulation. To control a hybrid inverter as part of an active harmonic filter, a method of pulse-width modulation of the carrier is proposed. It allows reducing the common-mode voltage, switching losses, and minimizing current and voltage harmonics. The paper describes the PWM algorithm, on the basis of which the control signals are modulated and then compared with a triangular carrier to generate a sequence of pulses that turn on or turn off semiconductor switches. The purpose of the proposed solutions is to improve harmonic distortion caused by non-linear load in a 0.4 kV low-voltage system. The results of modeling the proposed active harmonic filter circuit are presented. Based on the studies performed, it is shown that the use of an active harmonic filter based on a 5-stage hybrid inverter with pulse-width modulation control is an effective means of filtering higher harmonics on 0.4 kV low voltage buses in the presence of a nonlinear load, which allows solving the problem of eliminating the impact of higher harmonics on the production activities of the enterprise.

scholarly journals Influence of Hydraulics on Electric Drive Operational Characteristics in Pump-Controlled Actuators

Actuators ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 321
Author(s):  
Viacheslav Zakharov ◽  
Tatiana Minav
Keyword(s):  
Stability Analysis ◽  
Electric Drive ◽  
Electric Motor ◽  
Pulse Width Modulation ◽  
Frequency Converter ◽  
Process Time ◽  
Stable Operation ◽  
Model And Simulation ◽  
Operational Characteristics ◽  
The Impact

Transitioning from a valve- to pump-controlled system has been observed in working hydraulics to reduce energy consumption and accelerate the response to decarbonization requirements in Non-road Mobile Machinery (NRMM). The utilization of an electric motor as a prime mover significantly enhances the chances of completing this task. While the concept of combining hydraulics with an electric motor is not new, the functionality of electro-hydraulics can be improved due to multidisciplinary domains, the impact of the electric drive and its control is usually underestimated. Thus, this study aims to evaluate the influence of hydraulics on electric drive operational characteristics in pump-controlled actuators. It utilizes an electro-hydraulic model and simulation study under various conditions, a stability analysis, and a Pulse Width Modulation (PWM) of the frequency converter (FC) evaluation on a selected variable speed pump-controlled actuator to demonstrate the influence of hydraulics on an electric drive. Experimental validation of the model demonstrated an acceptable accuracy of 5%. Moreover, the stability analysis indicated a rise time of about 0.051 s, an overshoot of 0.53%, a transient process time of 0.13 s, and a steady-state value difference of 0.16%; all of which guarantees stable operation of the electric drive with a hydraulic load. In addition, an optimal PWM of an FC frequency of 5 kHz was selected to guarantee accurate speed control with minimum overshoot.

IFRS IMPLEMENTATION AS ONE OF THE FACTORS FOR IMPROVING THE INVESTMENT CLIMATE IN UKRAINE

2017 ◽  
Author(s):  
Kateryna Sova ◽  
◽  
Natalia Yatsenko ◽  
Denys Zagirniak ◽  
◽  
...  
Keyword(s):  
Financial Reporting ◽  
Direct Investment ◽  
Financial Statements ◽  
International Standards ◽  
Investment Climate ◽  
The European Union ◽  
Economic Activities ◽  
Financial Reporting Standards ◽  
Almost All ◽  
The Impact

The article is devoted to the study of the impact of the introduction of International Financial Reporting Standards (IFRS) on changes in the investment climate in Ukraine. The relevance of the topic is that improving the practice of applying IFRS as a tool for exchanging financial information is one of the key conditions for improving the investment climate in Ukraine. The authors have created the generalized scheme that illustrates the chronological list of enterprises that are required by law to prepare financial statements in accordance with IFRS. It was noted that in 2018, in accordance with Part 2 of Article 12 of the law on accounting and financial reporting in Ukraine and resolution of the Cabinet of Ministers of Ukraine No. 547 from 11.07.2018, the criteria of enterprises that are required to prepare financial statements in accordance with IFRS were updated. This step significantly increased the level of application of international standards due to the adoption of such a decision at the legislative level. The dynamics of the number of IFRS enterprises in Ukraine was analyzed. The analysis showed that over the past three years, the number of almost all enterprises that must apply international standards has been growing. The advantages of using IFRS for different users of financial statements were determined. It was determined that the priority users of IFRS financial statements are investors. At the same time, it was noted that the main advantage for other users of financial statements prepared in accordance with international standards is the improvement of the investment climate. The dynamics of the Investment Attractiveness Index of Ukraine based on the Likert scale in the period from 2016 to 2020 was analyzed. The direct investment receipts to Ukraine from the European Union countries were studied. The dynamics of direct investment in the Ukrainian economy was analyzed for two types of economic activities that should form financial statements in accordance with IFRS, namely, the extractive industry and quarrying, as well as financial and insurance activities.

Alteraciones sistémicas y metabólicas producidas por lesión medular

2019 ◽  
Vol 1 (1) ◽  
pp. 59-75
Author(s):  
Gabriel Guízar Sahagún
Keyword(s):  
Spinal Cord ◽  
Daily Living ◽  
Autonomic Function ◽  
Clinical Presentation ◽  
Scientific Literature ◽  
International Standards ◽  
Therapeutic Approaches ◽  
Cord Injury ◽  
Life Threatening ◽  
The Impact

Besides the well-known loss of motor and sensory capabilities, people with spinal cord injury (SCI) experience a broad range of systemic and metabolic abnormalities including, among others, dysfunction of cardiovascular, respiratory, gastrointestinal, urinary, and endocrine systems. These alterations are a significant challenge for patients with SCI because such disorders severely interfere with their daily living and can be potentially life-threatening. Most of these disorders are associated with impairment of regulation of the autonomic nervous system, arising from disruption of connections between higher brain centers and the spinal cord caudal to the injured zone. Thus, the higher and more complete the lesion, the greater the autonomic dysfunction and the severity of complications.This article summarizes the medical scientific literature on key systemic and metabolic alterations derived of SCI. It provides information primarily focused on the pathophysiology and clinical presentation of these disorders, as well as some guides to prevent and alleviate such complications. Due to the impact of these alterations, this topic must be a priority and diffuse to those involved with the care of people with SCI, including the patient himself/herself. We consider that any collaborative effort should be supported, like the development of international standards, to evaluate autonomic function after SCI, as well as the development of novel therapeutic approaches.

Sign in / Sign up

Export Citation Format

Share Document