Active Control of Electromagnetic Waves in Layered Media Using a Current Source

2020 ◽  
Author(s):  
Shubin Zeng ◽  
Neil Jerome A. Egarguin ◽  
Daniel Onofrei ◽  
Jiefu Chen
Keyword(s):  
Active Control ◽  
Electromagnetic Waves ◽  
Current Source ◽  
Layered Media ◽  
A Current

scholarly journals Analytical Modeling and Validation of a Preloaded Piezoceramic Current Output

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 353
Author(s):  
Bin Zhang ◽  
Hongsheng Liu ◽  
Dezhi Li ◽  
Jinhui Liang ◽  
Jun Gao
Keyword(s):  
Energy Harvesting ◽  
Integrated Circuit ◽  
Microelectromechanical Systems ◽  
Experimental Testing ◽  
Current Source ◽  
Model Parameters ◽  
Current Output ◽  
System A ◽  
A Current ◽  
Piezoelectric Characteristics

Energy harvesting using piezoceramic has drawn a lot of attention in recent years. Its potential usage in microelectromechanical systems is starting to become a reality thanks to the development of an integrated circuit. An accurate equivalent circuit of piezoceramic is important in energy harvesting and the sensing system. A piezoceramic is always considered to be a current source according to empirical testing, instead of the derivation from its piezoelectric characteristics, which lacks accuracy under complicated mechanical excitation situations. In this study, a new current output model is developed to accurately estimate its value under various kinds of stimulation. Considering the frequency, amplitude and preload variation imposed on a piezoceramic, the multivariate model parameters are obtained in relation to piezo coefficients. Using this model, the current output could be easily calculated without experimental testing in order to quickly estimate the output power in energy harvesting whatever its geometric shape and the various excitations.

scholarly journals Integrated active and semi-active control for seat suspension of a heavy duty vehicle

2017 ◽  
Vol 29 (1) ◽  
pp. 91-100 ◽  
Author(s):  
Donghong Ning ◽  
Shuaishuai Sun ◽  
Haiping Du ◽  
Weihua Li
Keyword(s):  
Resonance Frequency ◽  
Active Control ◽  
Integrated Control ◽  
Relative Displacement ◽  
Magnetorheological Damper ◽  
Active Force ◽  
Heavy Duty ◽  
Force Output ◽  
Seat Suspension ◽  
A Current

In this article, an integrated active and semi-active seat suspension for heavy duty vehicles is proposed, and its prototype is built; an integrated control algorithm applied measurable variables (suspension relative displacement and seat acceleration) is designed for the proposed seat prototype. In this seat prototype, an active actuator with low maximum force output (70 N), which is insufficient for an active seat suspension to control the resonance vibration, is applied together with a rotary magnetorheological damper. The magnetorheological damper can suppress the high vibration energy in resonance frequency, and then a small active force can further improve the seat suspension performance greatly. The suspension’s dynamic property is tested with a MTS system, and its model is identified based on the testing data. A modified on–off controller is applied for the rotary magnetorheological damper. A [Formula: see text] controller with the compensation of a disturbance observer is used for the active actuator. Considering the energy saving, the control strategy is designed as that only when the magnetorheological damper is in the off state (0 A current), the active actuator will have active force output, or the active actuator is off. Both simulation and experiment are implemented to verify the proposed seat suspension and controller. In the sinusoidal excitations experiment, the acceleration transmissibility of integrated control seat has lowest value in resonance frequency and frequencies above the resonance, when compared with power on (0.7 A current), power off (0 A current) and semi-active control seat. In the random vibration experiment, the root mean square acceleration of integrated control seat suspension has 47.7%, 33.1% and 26.5% reductions when compared with above-mentioned three kinds of seat suspension. The power spectral density comparison indicates that the integrated seat suspension will have good performance in practical application. The integrated active and semi-active seat suspension can fill energy consumption gap between active and semi-active control seat suspension.

A Current Source for Picoammeter Calibration

2007 ◽  
Vol 56 (4) ◽  
pp. 1198-1201 ◽  
Author(s):  
Luca Callegaro ◽  
Vincenzo D'Elia ◽  
Bruno Trinchera
Keyword(s):  
Current Source ◽  
A Current

scholarly journals Space vector PWM sequence and harmonic comparison for high power current source rectifier

2021 ◽  
Author(s):  
Nagaraja H. Chikkegowda
Keyword(s):  
High Power ◽  
Current Source ◽  
Switching Frequency ◽  
Space Vector Pwm ◽  
Vector Sequence ◽  
Space Vector ◽  
Switching Losses ◽  
Vector Sequences ◽  
Vector Modulation ◽  
A Current

The space vector PWM (SVPWM) schemes for high power current source drives normally produce low order harmonics due to low switching frequency. To provide a SVPWM with the best harmonic performance, different space vector sequences suitable for a current source rectifier (CSR) are investigated in this project. Details on how to achieve the waveform symmetries with minimum switching frequency for each sequence are discussed. A thorough comparison of the harmonic performance of different space vector sequences based on current source rectifier implementations is carried out. An optimum space vector modulation (SVM) method is proposed to achieve the best line current THD and reduced switching losses. The space vector sequence investigation has been verified in simulation and experimentally using a 10kVA GCT based CSR prototype.

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