Relationship between module performance and the shading area for modules with different circuit connection mode

Partial shading is very common in photovoltaic (PV) systems. The mismatch losses and hot-spot effects caused by partial shading can not only affect the output power of a solar system, but also can bring security and reliability problems. This paper centers on the silicon crystalline PV module technology subjected to operating conditions with some cells partially or fully shaded. A comparison of the electrical and hot-pot performance results for four different connection mode PV modules without shading and with partial or full shading is presented. Bypass diode of different modules would start up in the different conditions with increasing shading area. We found that the regular half-cell module degraded about 60% than its non-shaded power, which is about 30% less than the other three modules, when the short edges of these modules were shaded. The highest hot-spot temperature of the regular half-cell module was 75.5C, which is the lowest among the four modules before diode started up.

Hierarchical Modular Battery Equalizer With Open-Loop Control and Mitigated Recovery Effect

In this manuscript, an advanced battery equalizer with open-loop control is proposed. This equalizer is based on a two-layer hierarchical modular architecture. The top stringto- module (S2M) layer consists of a half-bridge inverter and a voltage multiplier (VM) rectifier, and the bottom cell-to-cell (C2C) layer is implemented by bidirectional buck-boost units. Without state-of-charge (SOC) estimation, the battery charge can be automatically transferred from high-voltage cell-modules/cells to low-voltage ones. Only a pair of symmetrical pulse width modulation (PWM) driving signals with fixed switching frequency and duty cycle are required.This reduces the control complexity remarkably. Meanwhile, the balancing current of each balancing path naturally attenuates with the convergence of cell-module/ cell voltages. This ensures a fast balancing of cell-module/cell with large voltage mismatch. The battery-recovery-effect induced balancing error is also effectively mitigated. Moreover, simple control facilitates a simultaneous module and cell voltage balancing in static, charging, and discharging conditions. The operation principles are analyzed in detail. An experimental platform with eight series-connected batteries is built and tested. The measured results well validate the theoretical analysis. Both cell and module voltages automatically converge with clearly mitigated recovery effect.

The effectiveness of a mini photovoltaic cell by using light LED bulbs as a source of photon energy

Muxindo’s LED bulb is one of the brands that are widely used by Indonesian people as lighting in the home. This study aims to look at the effectiveness of the light spectrum of the 10, 15 and 20 Watt LED power bulbs as an energy source to generate electrical energy in monocrystalline mini photovoltaic (PV) cell module. The light spectrum is compared with and without the Fresnel lens before being transmitted to the PV surface. The test results show that the PV output power is much better with a Fresnel lens (4.06> 1.67) mW. The efficiency of PV with lens displays slightly different figures, 3.77% at 15 Watt bulb power, while without Fresnel lenses, PV efficiency is 4.86% with a 20 Watt bulb. Need further research, for example, with Philips brand LED bulbs

One-pot synthesis of (R)- and (S)-phenylglycinol from bio-based l-phenylalanine by an artificial biocatalytic cascade

Chiral phenylglycinol is a very important chemical in the pharmaceutical manufacturing. Current methods for synthesis of chiral phenylglycinol often suffered from unsatisfied selectivity, low product yield and using the non-renewable resourced substrates, then the synthesis of chiral phenylglycinol remain a grand challenge. Design and construction of synthetic microbial consortia is a promising strategy to convert bio-based materials into high value-added chiral compounds. In this study, we reported a six-step artificial cascade biocatalysis system for conversion of bio-based l-phenylalanine into chiral phenylglycinol. This system was designed using a microbial consortium including two engineered recombinant Escherichia coli cell modules, one recombinant E. coli cell module co-expressed six different enzymes (phenylalanine ammonia lyase/ferulic acid decarboxylase/phenylacrylic acid decarboxylase/styrene monooxygenase/epoxide hydrolase/alcohol dehydrogenase) for efficient conversion of l-phenylalanine into 2-hydroxyacetophenone. The second recombinant E. coli cell module expressed an (R)-ω-transaminase or co-expressed the (S)-ω-transaminase, alanine dehydrogenase and glucose dehydrogenase for conversion of 2-hydroxyacetophenone into (S)- or (R)-phenylglycinol, respectively. Combining the two engineered E. coli cell modules, after the optimization of bioconversion conditions (including pH, temperature, glucose concentration, amine donor concentration and cell ratio), l-phenylalanine could be easily converted into (R)-phenylglycinol and (S)-phenylglycinol with up to 99% conversion and > 99% ee. Preparative scale biotransformation was also conducted on 100-mL scale, (S)-phenylglycinol and (R)-phenylglycinol could be obtained in 71.0% and 80.5% yields, > 99% ee, and 5.19 g/L d and 4.42 g/L d productivity, respectively. The salient features of this biocatalytic cascade system are good yields, excellent ee, mild reaction condition and no need for additional cofactor (NADH/NAD+), provide a practical biocatalytic method for sustainable synthesis of (S)-phenylglycinol and (R)-phenylglycinol from bio-based L-phenylalanine.

One-pot Synthesis of (R)- and (S)-phenylglycinol From Bio-based L-phenylalanine by an Artificial Biocatalytic Cascade

Chiral phenylglycinol is a very important chemical in the pharmaceutical manufacturing. Current methods for synthesis of chiral phenylglycinol often suffered from unsatisfied selectivity, low product yield and using the non-renewable resourced substrates, then the synthesis of chiral phenylglycinol remain a grand challenge. Design and construction of synthetic microbial consortia is a promising strategy to convert bio-based materials to high value-added chiral compounds. In this study, we reported a six-step artificial cascade biocatalysis system for conversion of biobased L-phenylalanine to yield chiral phenylglycinol. The cascade biocatalysis system was conducted by a microbial consortium composed of two engineered recombinant Escherichia coli cells modules, one recombinant E. coli cell module co-expression of six different enzymes (phenylalanine ammonia lyase/ferulic acid decarboxylase/phenylacrylic acid decarboxylase/styrene monooxygenase/epoxide hydrolase/alcohol dehydrogenase) for efficient conversion of L-phenylalanine into 2-hydroxyacetophenone. The second recombinant E. coli cell module expression of an (R)-ω-transaminase or co-expression of the (S)-ω-transaminase, alanine dehydrogenase and glucose dehydrogenase for conversion of 2-hydroxyacetophenone to (S)- or (R)-phenylglycinol, respectively. Combining the two engineered E. coli cell modules, after the optimization of bioconversion conditions (including pH, temperature, glucose concentration, amine donor concentration and cell ratio), L-phenylalanine could be easily converted to (R)-phenylglycinol and (S)-phenylglycinol with up to 99% conversion and >99% ee. Preparative scale biotransformation was also conducted on 100 mL scale, (S)-phenylglycinol and (R)-phenylglycinol were obtained in 71.0% and 80.5% yield, >99% ee, and 5.19 g/L.d and 4.42 g/L.d productivity, respectively. The salient features of this biocatalytic cascade system are good yields, excellent ee, mild reaction conditions and no need for additional cofactor (NADH/NAD+), provide a practical biocatalytic method for sustainable synthesis of (S)-phenylglycinol and (R)-phenylglycinol from biobased L-phenylalanine.