Analytical solution to orifice design in a rotary valve controlled electro-hydraulic vibration exciter for high-frequency sinusoidal vibration waveform

2019 ◽  
Vol 233 (5) ◽  
pp. 1098-1108
Author(s):  
He Wang ◽  
Chengwen Wang ◽  
Long Quan ◽  
Guofang Gong ◽  
Wenjing Li
Keyword(s):  
Analytical Solution ◽  
Vibration Frequency ◽  
Axial Length ◽  
High Frequency ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Design Solution ◽  
Vibration Exciter ◽  
Rotary Valve ◽  
Sinusoidal Vibration

The present study is focused on a novel method for the acquisition of high-frequency sinusoidal vibration waveform with electro-hydraulic vibration exciter. A rotary valve controlled electro-hydraulic vibration exciter is proposed to make it easier to obtain high vibration frequency than the conventional servo valve controlled counterpart. Three common used offices are taken into consideration: rectangular orifice, triangular orifice, and semicircular orifice. Analytical solution to orifice design of shape and axial length is suggested for the accurate control of vibration waveform. Harmonic theory borrowed from electronic technology is used as an evaluation index for the shape of vibration waveform. The orifice shape design decision is made according to the total harmonic distortion of vibration waveform. The nonlinear differential equation which models vibration waveform is established. The orifice axial length is designed according to the supply pressure, vibration frequency, and amplitude. Both theoretical and experimental results show that rectangular orifice is desirable for high-frequency sinusoidal vibration waveforms. With the orifice design solution, the proposed vibration exciter can output the vibration waveform with total harmonic distortion of less than 1% as compared with sinusoidal waveform and maximum error of 5% as compared with experimental value at vibration frequency of higher than 100 Hz, and greatly extend the frequency bandwidth when sinusoidal vibration waveform is required.

A rotary valve controlled electro-hydraulic vibration exciter

2016 ◽  
Vol 230 (19) ◽  
pp. 3397-3407 ◽  
Author(s):  
He Wang ◽  
Guofang Gong ◽  
Hongbin Zhou ◽  
Wei Wang ◽  
Yi Liu
Keyword(s):  
Vibration Frequency ◽  
Harmonic Distortion ◽  
Response Speed ◽  
Slide Valve ◽  
Vibration Exciter ◽  
Rotary Valve ◽  
Sinusoidal Vibration ◽  
Servo Valve ◽  
Electric System ◽  
Supply Pressure

When sinusoidal vibration waveform is required, the frequency bandwidth of conventional electro-hydraulic vibration exciter controlled by servo valve is always limited to a rather narrow range due to the limits of slide valve structure and response speed, and no parameter is available for defining and evaluating the waveform quality. In this paper, a novel electro-hydraulic vibration exciter controlled by electromotor driven rotary valve is proposed to significantly extend the frequency range compared to the conventional servo valve controlled counterpart. Total harmonic distortion (THD) theory which is usually used to cope with voltage and current in electric system is borrowed to evaluate the quality of theoretical and experimental vibration waveforms at different supply pressures and vibration frequencies, quantitatively and qualitatively. The results show that the waveform quality is mainly influenced by the 3rd harmonic resonance. The proposed vibration exciter can output sinusoidal waveform with THD less than 5% at the vibration frequency higher than 70 Hz. In this frequency domain, the supply pressure has an extremely low impact on the THD of the waveform. The amplitude of the waveform can be adjusted by changing the supply pressure with almost no effect to the waveform quality at a certain vibration frequency.

A novel method for high-frequency non-sinusoidal vibration waveforms with uniaxial electro-hydraulic shaking table based on Fourier series

2020 ◽  
pp. 107754632096171
Author(s):  
He Wang ◽  
Zhen Chen ◽  
Jiahai Huang
Keyword(s):  
Fourier Series ◽  
Vibration Frequency ◽  
High Frequency ◽  
Narrow Range ◽  
Harmonic Distortion ◽  
Shaking Table ◽  
Rotary Valve ◽  
Sinusoidal Vibration ◽  
Supply Pressure ◽  
Novel Method

In this article, a rotary valve is developed to obtain accurate high-frequency sinusoidal vibration waveforms. Then, a uniaxial electro-hydraulic shaking table controlled by a set of parallel rotary valves is constructed, which can superpose the sinusoidal vibration waveforms. The non-sinusoidal vibration waveforms including triangular vibration waveform, rectangular vibration waveform, sawtooth vibration waveform and trapezoidal vibration waveform are generated by adjusting the spool rotation speed based on the Fourier series. The results show that with one rotary valve, the uniaxial electro-hydraulic shaking table can output accurate high-frequency sinusoidal vibration waveforms and the total harmonic distortion is less than 1% at high vibration frequency. Compared with the standard vibration waveform, the error of the generated vibration waveform is very small. For the rectangular vibration waveform and sawtooth vibration waveform, the error is less than 6%, and for the triangular vibration waveform and trapezoidal vibration waveform, the error is less than 3%. The impacts of the working conditions on the error of the generated vibration waveform are very small. The proposed method for the accurate high-frequency non-sinusoidal vibration waveform is very effective and can be applied in high vibration frequency and different load masses. With the increase of the supply pressure, the amplitude of the generated vibration waveforms increases, while the error changes in a rather narrow range. The amplitude can be adjusted by changing the supply pressure with almost no effect on the accuracy of the vibration waveform.

scholarly journals Analysis on vibration for a high-frequency electro-hydraulic cleaning system controlled by improved two-dimensional rotary valve

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881141
Author(s):  
Xiancheng Ji ◽  
Yan Ren ◽  
Hesheng Tang
Keyword(s):  
Vibration Frequency ◽  
High Frequency ◽  
Functional Materials ◽  
Pressure Amplitude ◽  
Two Dimensional ◽  
Rotary Valve ◽  
Sinusoidal Vibration ◽  
High Frequency Vibration ◽  
Cleaning System ◽  
Sinusoidal Waveform

Conventional high-frequency cleaners utilize functional materials (e.g. piezoelectric ceramics, magnetostrictive materials) excited by electrical signals to realize high-frequency vibration, even ultrasonic vibration. However, it is difficult to produce a large force without sacrificing bandwidth because of the physical characteristics of materials themselves. Therefore, a high-frequency high-power cleaner driven by electro-hydraulic excitation is proposed. Only a few studies are performed on electro-hydraulic cleaners, owing to the limitation of frequency bandwidth of the electro-hydraulic system. Thus, a rotary valve named two-dimensional valve is improved and adopted to improve high-frequency performances of the electro-hydraulic cleaner. In this article, a two-dimensional rotary valve with a linear variable differential transformer is designed, and the vibration characteristics of the electro-hydraulic cleaner controlled by this valve are discussed in detail, especially vibration acceleration, vibration frequency, and pressure amplitude. A prototype of the electro-hydraulic cleaner is modeled and both a theoretical analysis and experimental investigation are carried out. Theoretical and experimental results indicate that the electro-hydraulic cleaning system outputs sinusoidal vibration waveforms, especially in a high-frequency domain, which could realize the vibration frequency of 2669 Hz. The measured waves at different frequencies (below the resonant frequency) demonstrate different distortions compared with the sinusoidal waveform. These distortions can be associated with the hydraulic resonance. At hydraulic resonance (1903 Hz), the amplitude is increased significantly and the vibration waveform becomes more pronounced. Nevertheless, the study does provide an access to the electro-hydraulic high-frequency vibration applied in cleaning or other engineering cases.

Investigation and Improvement of Self-Oscillating Electronic Ballast for Local Fluorescent Emergency Light

2012 ◽  
Vol 614-615 ◽  
pp. 1539-1546
Author(s):  
Muhamad Fairus Hamid ◽  
Norazlan Hashim ◽  
Ahmad Farid Abidin
Keyword(s):  
High Frequency ◽  
Harmonic Distortion ◽  
Experimental Results ◽  
Total Harmonic Distortion ◽  
Switching Frequency ◽  
Switching Device ◽  
Electronic Ballast ◽  
Rectifier Circuit ◽  
Fluorescent Lamps

This paper presents an analysis and improvement of self-oscillation electronic ballast for local emergency light. The improvement circuit has been presented by replacing the original BJTs with MOSFETs as a switching device. Also, 555-timer has been used to drive the MOSFETs instead of the ballast feedback in the original circuit. This electronic ballast start and regulate fluorescent lamps by converting a DC supply to high ignition AC voltage by a rectifier circuit with switching frequency in the range of 20 kHz -1MHz. Operation at high frequency has two advantages; an improved efficiency and elimination of flickering in the lamps. The simulation has been done by using PSIM Simulink software and its results have been compared with experimental results. The results shows that by using MOSFETs as a switching device, the Total Harmonic Distortion (THD) has been reduced and the brightness of lamp tube has been increased greatly.

Harmonic Investigation and Simulation of Full Bridge LCL Resonant Inverter

2011 ◽  
Vol 403-408 ◽  
pp. 3600-3607
Author(s):  
S. Selvaperumal ◽  
C.Christober Asir Rajan
Keyword(s):  
Power Systems ◽  
High Frequency ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Zero Voltage Switching ◽  
Resonant Inverter ◽  
Ac Power ◽  
Resistive Loads ◽  
Zero Voltage ◽  
Voltage Switching

This paper presents 250W, 20 KHz LCL resonant inverter having Efficiencies greater than 95% were obtained down to resistive loads of 50%. Efficiencies greater than 80% were obtained at significantly reduced loads (11%). Operation above resonance was utilized to increase the efficiency and maintain zero voltage switching (ZVS) for varied loads. Total harmonic distortion (THD) of less than 8% was achieved for all resistive loads. The above results were obtained from evaluation version of PSIM also used to model the LCL topology for varied loads and LCL configurations. A LCL Resonant Inverter is proposed for applications in high frequency distributed AC power systems.

scholarly journals A High Bandwidth-Power Efficiency, Low THD2,3 Driver Amplifier with Dual-Loop Active Frequency Compensation for High-Speed Applications

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2311
Author(s):  
Ximing Fu ◽  
Kamal El-Sankary ◽  
Yadong Yin
Keyword(s):  
High Frequency ◽  
Power Efficiency ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Cmos Process ◽  
Phase Margin ◽  
Frequency Compensation ◽  
High Bandwidth ◽  
Driver Amplifier ◽  
Frequency Phase

This paper presents a driver amplifier with high bandwidth-power efficiency, high capacitor-driving capacity, and low total harmonic distortion (THD). One complementary differential pair composed of self-cascode transistors is incorporated to obtain a full input voltage swing. Flipped voltage follower (FVF) buffers are applied as second stage to drive the last class-AB output stage. Moreover, a dual-loop active-feedback frequency compensation (DLAFC) is presented, which can stabilize the proposed multistage amplifier and keep the dominant pole on high frequency to obtain high-frequency total harmonic distortion (THD) suppression. To achieve a low-frequency phase margin protection (PMP), one left half-plane (LHP) zero is introduced to compensate for the nondominant pole caused by the load capacitor. Meanwhile, two high-frequency LHP zeros are injected to achieve high-frequency phase margin boosting (PMB) and reduce the amplifier’s settling time and integration area. This proposed amplifier is implemented in a standard DBH 0.18 μm 5 V CMOS process, and it achieves over 115-dB DC gain, 150–300 MHz GBW under 0–100 p load capacitors, ultra-high THD2,3 suppression ranges from 100 kHz to 10 MHz under 1–2 V output swing, and over 250 V/μs average slew rate, by only dissipating 12.5 mW at 5 V power supply.

Reduction of high‐frequency injection losses, acoustic noise and total harmonic distortion in IPMSM sensorless drives

2019 ◽  
Vol 12 (12) ◽  
pp. 3197-3207 ◽  
Author(s):  
Ahmadreza Alaei ◽  
Sayed Morteza Saghaeian Nejad ◽  
Jacek F. Gieras ◽  
Dong‐Hee Lee ◽  
Jin‐Woo Ahn
Keyword(s):  
High Frequency ◽  
Acoustic Noise ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Sensorless Drives
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