Low-Frequency Pulse Width Modulation Design for HVAC Compressors

2009 ◽  
Author(s):  
William Burke ◽  
David Auslander
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Low Frequency ◽  
Air Conditioner ◽  
Saturation Power ◽  
Compressor Power ◽  
Pump Compressor ◽  
Long Pulse ◽  
Hysteresis Control ◽  
Frequency Pulse

This paper discusses the design of low-frequency pulse width modulation for heating ventilation and air conditioning (HVAC) compressors. HVAC units are traditionally controlled using nonlinear control techniques like hysteresis control. Using a very long pulse width, this method can treat an on/off air conditioner or heat pump compressor as a variable input for which traditional linear (or nonlinear) controls can be applied. The key advantage of this method is direct control over the compressor power using tunable saturation. Power control is especially useful when considering load management and real time energy pricing.

High‐power‐factor dimmable LED driver with low‐frequency pulse‐width modulation

2016 ◽  
Vol 9 (10) ◽  
pp. 2139-2146 ◽  
Author(s):  
Hung‐Liang Cheng ◽  
Yong‐Nong Chang ◽  
Chun‐An Cheng ◽  
Chien‐Hsuan Chang ◽  
Yu‐Hung Lin
Keyword(s):  
Power Factor ◽  
High Power ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Low Frequency ◽  
Led Driver ◽  
High Power Factor ◽  
Frequency Pulse

scholarly journals THD Reduction in Multi-Level Inverters based on Multicarrier Pulse Width Modulation Technique

2020 ◽  
Vol 9 (4) ◽  
pp. 1970-1977
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Harmonic Distortion ◽  
Low Frequency ◽  
Voltage Source ◽  
Power Sources ◽  
Multilevel Inverters ◽  
Modulation Technique ◽  
Multicarrier Pwm ◽  
Frequency Pulse

t Due to the advent of technology, electronic equipments are much more sensitive to harmonic and its analysis play an important role whereby reducing the distortion due to harmonics needs attention. To meet the requirements of the industries, harmonic free-high rating power sources are in high demand. Total Harmonic Distortion (THD) is an indicator of AC voltage source quality. In case of inverters, one such way to reduce THD would be the use of Pulse Width Modulation (PWM). The existing methods mainly use the low frequency pulse width modulation techniques for the switching. Control methods employing high frequency switching techniques held in controlling THD with proper application of filters. This paper analyses THD in multilevel inverters using multicarrier PWM technique with five pulse width modulation technique through MATLAB simulations. Finally, a comparison is done to find the less harmonic generated PWM method using fewerfilters.

Pulsed-DC Electrospray for Biopolymer Particle Production

2009 ◽  
Vol 1239 ◽  
Author(s):  
Cho-Hui Lim ◽  
Kiersten R Schierbeek ◽  
Michael E Mullins
Keyword(s):  
Pulse Width ◽  
Particle Production ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Process Conditions ◽  
High Duty Cycle ◽  
Pulsed Dc ◽  
High Pulse ◽  
Long Pulse ◽  
Frequency Pulse

AbstractPLLA microparticles were successfully fabricated via pulsed-DC electrospray. In this study, we investigated the effect of the pulsed voltage characteristics (e.g. pulse frequency, pulse amplitude and pulse width) on the particle’s size. We found that pulse frequency, pulse amplitude, pulse width, and the combinations of these factors had a statistically significant effect on the particle’s size. The process conditions to obtain smaller particles with uniform shape and size are a low pulse frequency, high pulse amplitude, and long pulse width (or a high duty cycle).

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.

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