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.

Dynamic vacuum pressure tracking control with high-speed on-off valves

2018 ◽  
Vol 232 (10) ◽  
pp. 1325-1336 ◽  
Author(s):  
Gang Yang ◽  
Kai Chen ◽  
Linglong Du ◽  
Jingmin Du ◽  
Baoren Li
Keyword(s):  
Mass Flow ◽  
Pulse Width ◽  
High Speed ◽  
Pulse Width Modulation ◽  
Sliding Mode ◽  
Tracking System ◽  
Vacuum Pressure ◽  
Chamber Pressure ◽  
Asymmetric Structure ◽  
The Impact

A vacuum pressure tracking system with high-speed on-off valves is a discontinuous system due to the discrete nature of high-speed on-off valves. Chamber pressure changes in the system are determined by the mass flow rates during the processes of charging and discharging. Here, a sliding mode controller with an asymmetric compensator based on average mass flow rate is designed for accurate vacuum pressure tracking. The controller output signal is converted into the duty cycles of the high-speed on-off valves via a pulse width modulation pulsing scheme. Owing to the extreme asymmetry of the processes, an asymmetric structure comprising one high-speed on-off valve in the charging unit and three high-speed on-off valves in the discharging unit is applied to weaken the impact of asymmetry. In addition, an asymmetric compensator is also designed to modify the pulse width modulation pulsing scheme to further eliminate the asymmetry. Experimental results indicate that the proposed controller achieves better performance in pressure tracking with the asymmetric compensator overcoming process asymmetry and enhancing system robustness.

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 Novel Intelligent and Sensorless Proportional Valve Control with Self-Learning Ability

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Bayram Akdemir
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Low Voltage ◽  
Control Unit ◽  
Control Signal ◽  
Learning Ability ◽  
Learning Abilities ◽  
Valve Control ◽  
Self Learning

Linear control is widely used for any fluid or air flows in many automobile, robotics, and hydraulics applications. According to signal level, valve can be controlled linearly. But, for many valves, hydraulics or air is not easy to control proportionally because of flows dynamics. As a conventional solution, electronic driver has up and down limits. After manually settling up and down limits, control unit has proportional blind behavior between two points. This study offers a novel valve control method merging pulse width and amplitude modulation in the same structure. Proposed method uses low voltage AC signal to understand the valve position and uses pulse width modulation for power transfer to coil. DC level leads to controlling the valve and AC signal gives feedback related to core moving. Any amplitude demodulator gives core position as voltage. Control unit makes reconstruction using start and end points to obtain linearization at zero control signal and maximum control signal matched to minimum demodulated amplitude level. Proposed method includes self-learning abilities to keep controlling in hard environmental conditions such as dust, temperature, and corrosion. Thus, self-learning helps to provide precision control for hard conditions.

scholarly journals Research on Modified Hybrid Frequency Modulation Technology of Type-III Asymmetric CHB Multilevel Inverters

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 263
Author(s):  
Manyuan Ye ◽  
Wei Ren ◽  
Qiwen Wei ◽  
Guizhi Song ◽  
Zhilin Miao
Keyword(s):  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Output Line ◽  
Line Voltage ◽  
Multilevel Inverters ◽  
Type Iii ◽  
Hybrid Frequency ◽  
Frequency Pulse

Asymmetric Cascaded H-bridge (ACHB) level inverters can output more voltage waveforms with fewer cascaded units while ensuring the quality of output voltage waveforms, so they have attracted more and more attention. Taking the topology of Type-III asymmetric CHB multilevel inverters as the research object, a Modified Hybrid Frequency Pulse Width Modulation (MHF-PWM) strategy is proposed in this paper. This modulation strategy overcomes the local overshoot of low-voltage unit in the presence of traditional Hybrid Frequency Pulse Width Modulation (HF-PWM), thus completely eliminating the low frequency harmonics in the output voltage waveform of Type-III ACHB nine-level inverters, and the Total Harmonic Distortion (THD) of output line voltage of the modulation strategy is lower than that of PS-PWM strategy in the whole modulation degree, which effectively improves the quality waveform of the output line voltage. At the same time, the strategy can also improve the problems of current backflow and energy feedback caused by the high-voltage unit pouring current to the low-voltage unit, thereby reducing the imbalance of the output power of the high-voltage and low-voltage units. Finally, the Matlab/Simulink simulation model and experimental platform are established to verify the validity and practicality of the modulation strategy.

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 Power Quality Improvement with a Pulse Width Modulation Control Method in Modular Multilevel Converters under Varying Nonlinear Loads

2020 ◽  
Vol 10 (9) ◽  
pp. 3292 ◽  
Author(s):  
Majid Mehrasa ◽  
Radu Godina ◽  
Edris Pouresmaeil ◽  
Eduardo M. G. Rodrigues ◽  
João P. S. Catalão
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Second Order ◽  
Control Law ◽  
Nonlinear Load ◽  
Control Laws ◽  
The Third ◽  
Circulating Current ◽  
Harmonic Components ◽  
Circulating Currents

In order to reach better results for pulse width modulation (PWM)-based methods, the reference waveforms known as control laws have to be achieved with good accuracy. In this paper, three control laws are created by considering the harmonic components of modular multilevel converter (MMC) state variables to suppress the circulating currents under nonlinear load variation. The first control law consists of only the harmonic components of the MMC’s output currents and voltages. Then, the second-order harmonic of circulating currents is also involved with both upper and lower arm currents in order to attain the second control law. Since circulating current suppression is the main aim of this work, the third control law is formed by measuring all harmonic components of circulating currents which impact on the arm currents as well. By making a comparison between the switching signals generated by the three proposed control laws, it is verified that the second-order harmonic of circulating currents can increase the switching losses. In addition, the existence of all circulating current harmonics causes distributed switching patterns, which is not suitable for the switches’ lifetime. Each upper and lower arm has changeable capacitors, named “equivalent submodule (SM) capacitors” in this paper. To further assess these capacitors, eliminating the harmonic components of circulating currents provides fluctuations with smaller magnitudes, as well as a smaller average value for the equivalent capacitors. Moreover, the second-order harmonic has a dominant role that leads to values higher than 3 F for equivalent capacitors. In comparison with the first and second control laws, the use of the third control-law-based method will result in very small circulating currents, since it is trying to control and eliminate all harmonic components of the circulating currents. This result leads to very small magnitudes for both the upper and lower arm currents, noticeably decreasing the total MMC losses. All simulation results are verified using MATLAB software in the SIMULINK environment.

scholarly journals Modified Modulation Strategy of 1: 1: 2 Asymmetric Nine-Level Inverter and Its Power Balance Method

Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 75
Author(s):  
Manyuan Ye ◽  
Qiwen Wei ◽  
Wei Ren ◽  
Guizhi Song
Keyword(s):  
Output Power ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Low Voltage ◽  
Balance Control ◽  
Power Balance ◽  
Switching Loss ◽  
Switching Losses ◽  
Hybrid Frequency

The three unit nine-level inverter can output more voltage levels with fewer h-bridge units, while having better output waveform quality. However, in the conventional hybrid frequency modulation strategy, only one low-voltage unit adopts pulse width modulation (PWM), which causes the problem of switching loss and uneven heat distribution between the two low-voltage units. At the same time, the output power of the conventional modulation strategy is unbalanced. Aiming to resolve the above problems, a modified hybrid modulation strategy and a power balance control method under the strategy is proposed in this paper. The modulation strategy achieves output power balance between the three units and an even distribution of switching losses between the two low voltage units while maintaining the same output power quality. Simulation and experimental results verify the feasibility of the modulation strategy.

Performance Analysis of H-bridge and T-Bridge Multilevel Inverters for Harmonics Reduction

2018 ◽  
Vol 9 (1) ◽  
pp. 231 ◽  
Author(s):  
S. Usha ◽  
C. Subramani ◽  
A. Geetha
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Harmonic Distortion ◽  
Input Voltage ◽  
Multilevel Inverter ◽  
Multilevel Inverters ◽  
Semiconductor Switches ◽  
Output Waveform ◽  
Cascaded Multilevel Inverter ◽  
Sinusoidal Pulse Width Modulation

This paper deals with the design of cascaded 11 level H- bridge inverter. It includes a comparison between the 11 level H-bridge and T-bridge multilevel inverter. The cascaded inverter of higher level is a very effective and practical solution for reduction of total harmonic distortion (THD).These cascaded multilevel inverter can be used for higher voltage applications with more stability. As the level is increased the output waveform becomes more sinusoidal in nature. The inverter is designed using multicarrier sinusoidal pulse width modulation technique for generating triggering pulses for the semiconductor switches used in the device. Through this paper it will be proved that a cascaded multilevel H-bridge topology has higher efficiency than a T-bridge inverter, as whichever source input voltage is provided since input is equal to the output voltage. In T-bridge inverter, the output obtained is half of the applied input, so efficiency is just half as compared to H-bridge. The output waveform is distorted and has higher THD.  The simulation is performed using MATLAB /Simulink 2013 software.

scholarly journals Experimental research on the influence of the pulse injector control parameters on its flow rate

2015 ◽  
Vol 163 (4) ◽  
pp. 15-20
Author(s):  
Jacek CZARNIGOWSKI
Keyword(s):  
Experimental Research ◽  
Mass Flow ◽  
Flow Rate ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Control Signal ◽  
Control Parameters ◽  
Pulse Modulation ◽  
Fuel Mass ◽  
The Impact

The paper presents the results of the impact of the control parameters on the fuel mass flow from the injector. The control parameters examined in the paper were: frequency and pulse width modulation of the modulated control signal (the second part of the injector control signal). The analysis covers 6 injector types of different design of the valve element and the coil. The experiments have shown that the frequency of the signal does not affect the injector performance, contrary to pulse modulation affecting the injector performance significantly.

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