Frequency and Time-Domain Comparison between LCL and LLCL Filters for a Grid-Connected Inverter Using Selective Harmonic Modulation

This paper shows a comparison between the analytical design of a photovoltaic power station filter and a real-case filter. Indeed, the analytical filter considered in the design phase is an LCL filter, while the real case is an LLCL filter. This difference could impact the current harmonics rejected on the grid and breaks grid codes. The main objective of this study is to maximize the power injected into the network while respecting the harmonic rejection standards in force, namely, G5/4, French decree of 2008, and IEEE 519 standards, by adopting a current control design to improve the performance of a grid-connected three-phase inverter, which is regarded as the central component in a photovoltaic production system. The selective harmonic modulation strategy (SHM) is a common technique to achieve this goal. For that, a frequency and a time-domain comparison for a grid-connected inverter using both filters have been highlighted. Simulation results confirm the excellent transient behavior of both filter topologies and the advantage to consider the flexibility of LLCL filter when combined with SHM strategy. This manuscript is an extension of an earlier version of “Comparison between LCL and LLCL Filters for a Grid Connected Inverter Using Selective Harmonic Modulation.”

Photosynthesis dynamics and regulation sensed in the frequency domain

Foundations of photosynthesis research have been established mainly by studying the response of plants to changing light, typically to sudden exposure to a constant light intensity after a dark acclimation or to light flashes. This approach remains valid and powerful, but can be limited by requiring dark acclimation prior to time-domain measurements and often assumes that rate constants determining the photosynthetic response do not change between the dark- and light-acclimation.We present experimental data and a mathematical model demonstrating that these limits can be overcome by measuring plant responses to sinusoidally modulated light of varying frequency. By its nature, such frequency domain characterization is performed in light-acclimated plants with no need for prior dark acclimation. Amplitudes, phase shifts and upper harmonic modulation extracted from the data for a wide range of frequencies can target different kinetic domains and regulatory feedbacks. The occurrence of upper harmonic modulation reflects non-linear phenomena, including photosynthetic regulation. To support these claims, we present a frequency and time domain response in chlorophyll fluorescence emission of the green alga Chlorella sorokiniana in the frequency range 1000 – 0.001 Hz. Based on these experimental data and on numerical as well as analytical mathematical models, we propose that the frequency domain measurements can become a versatile new tool in plant sensing.One sentence summaryIt is proposed to characterize photosynthesis in the frequency domain without the need for dark adaptation and, thus, without assumptions about the dark-to-light transition.

Hearing As

Nearly everything ever written by philosophers on aspect perception has been about vision. This chapter catalogs some views and lessons regarding “seeing as,” and argues that not all of them carry over to aspect perception in hearing. In particular, the attention theory, very attractive for the case of vision, is not plausible for hearing. Hearing-as plays at least two central roles in human life. The chapter continues by illustrating them. One is in the appreciation of music: tonality, the ambiguity exploited in harmonic modulation, and the expressing of emotion. The other is in understanding speech: hearing sounds as speech at all, disambiguating utterances, and assigning illocutionary force.

A High-Data-Rate Area-Efficient Uni-Pulse Harmonic Modulation Transmitter for Implantable Neural Recording Microsystems

In this paper, a new data transmission method, named Uni-Pulse Harmonic Modulation (PHM), is presented and its concept is mathematically analyzed using the relations of inductive links. In this type of modulation, the Uni-Pulse passing through the primary coil generates an oscillation in the secondary coil, corresponding to its positive edge, and its negative edge is able to damp this oscillation. The Uni-Pulse passing the primary coil gives the opportunity to use a half-bridge driver instead of full-bridge driver and hence the chip area is desirably reduced. For implementing the proposed modulation technique, two half-bridge driver circuits are suggested that are controlled by series of transistors and transmission gates occupying 900[Formula: see text][Formula: see text]m2 and 737.87[Formula: see text][Formula: see text]m2 of chip area, respectively. Another merit of the proposed transmitters, besides their occupying low chip area, is that they can transmit data at the rate of 40[Formula: see text]MHz, while the received frequency is set at 66.6[Formula: see text]MHz. Therefore, the high amount of 60% is obtained for the data rate to carrier frequency ratio. Designed in a standard 0.18-[Formula: see text]m CMOS process, the proposed circuits operate at 1.8[Formula: see text]V supply voltages with consuming almost 400[Formula: see text]pj energy for transmitting each data bit.