A family of PWM based sliding mode voltage controllers for basic DC-DC converters

Author name used in this publication: Chi K. TseRefereed conference paper2005-2006 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

A unified approach to the design of PWM-based sliding-mode voltage controllers for basic DC-DC converters in continuous conduction mode

Author name used in this publication: Chi K. Tse2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Indirect sliding mode control of power converters via double integral sliding surface

Author name used in this publication: Chi K. Tse2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

An evaluation of the practicality of sliding mode controllers in DC-DC converters and their general design issues

Author name used in this publication: Chi K. TseRefereed conference paper2005-2006 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Implementation of pulse-width-modulation based sliding mode controller for boost converters

Author name used in this publication: Chi K. Tse2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Characterization of volatile organic compounds at a roadside environment in Hong Kong: An investigation of influences after air pollution control strategies

Vehicular emission is one of the important anthropogenic pollution sources for volatile organic compounds (VOCs). Four characterization campaigns were conducted at a representative urban roadside environment in Hong Kong between May 2011 and February 2012. Carbon monoxide (CO) and VOCs including methane (CH4), non-methane hydrocarbons (NMHCs), halocarbons, and alkyl nitrates were quantified. Both mixing ratios and compositions of the target VOCs show ignorable seasonal variations. Except CO, liquefied petroleum gas (LPG) tracers of propane, i-butane and n-butane are the three most abundant VOCs, which increased significantly as compared with the data measured at the same location in 2003. Meanwhile, the mixing ratios of diesel- and gasoline tracers such as ethyne, alkenes, aromatics, halogenated, and nitrated hydrocarbons decreased by at least of 37%. The application of advanced multivariate receptor modeling technique of positive matrix factorization (PMF) evidenced that the LPG fuel consumption is the largest pollution source, accounting for 60 ± 5% of the total quantified VOCs at the roadside location. The sum of ozone formation potential (OFP) for the target VOCs was 300.9 μg-O3 m-3, which was 47% lower than the value of 567.3 μg-O3 m-3 measured in 2003. The utilization of LPG as fuel in public transport (i.e., taxis and mini-buses) contributed 51% of the sum of OFP, significantly higher than the contributions from gasoline- (16%) and diesel-fueled (12%) engine emissions. Our results demonstrated the effectiveness of the switch from diesel to LPG-fueled engine for taxis and mini-buses implemented by the Hong Kong Special Administrative Region (HKSAR) Government between the recent ten years, in additional to the execution of substitution to LPG-fueled engine and restrictions of the vehicular emissions in compliance with the updated European emission standards

On the color stability of phosphor-converted white LEDs under DC, PWM, and bilevel drive

Most commercial white LEDs are made from nitride-based blue LEDs coated with yttrium aluminium garnet phosphor, which produce spectra that shift in opposite directions under the influences of drive current and junction temperature changes. This property gives rise to different emitted spectra, hence chromaticity properties, when the LED is driven/dimmed by different current waveforms. By using a commercial white LED sample, LUXEON K2, the effects of drive current and junction temperature on the changes of chromaticity coordinates are studied experimentally. The impact of dc, pulse width modulation (PWM), and bilevel current waveform is discussed through a graphical analysis, followed by experimental verification. It is proven that dc offers the best color stability over dimming due to the counteracting influences of drive current and junction temperature variations, whereas an LED constantly suffers from noneliminable chromaticity changes when driven by the PWM. Theoretical explanations are given to justify these cases, and it is found that, for the case of dc drive, an ideal heat sinks thermal resistance can be selected based on a simple equation to minimize the overall chromaticity change over dimming. This paper provides an in-depth discussion on the relations between the chromaticity properties of phosphor-converted (pc) white LEDs and the driving/dimming methods used. © 2011 IEEE.published_or_final_versio

A pulse-width-modulation based sliding mode controller for buck converters

Author name used in this publication: Martin K. H. CheungAuthor name used in this publication: Chi K. TseRefereed conference paper2003-2004 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

On the practical design of a sliding mode voltage controlled buck converter

Author name used in this publication: Martin K. H. CheungAuthor name used in this publication: Chi K. Tse2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe