Energy Management Strategy for Hybrid Energy Storage Electric Vehicles Based on Pontryagin’s Minimum Principle Considering Battery Degradation

The development of energy management strategy (EMS), which considers how power is distributed between the battery and ultracapacitor, can reduce the electric vehicle’s power consumption and slow down battery degradation. Therefore, the purpose of this paper is to develop an EMS for hybrid energy storage electric vehicles based on Pontryagin’s minimums principle (PMP) considering battery degradation. To verify the EMS, the hybrid energy storage electric vehicle model is first established. In the meantime, the battery cycle life trials are finished in order to develop a battery degradation model. Following that, a rule-based control approach and the PMP optimization algorithm are used to allocate power in a hybrid energy storage system (HESS) in a reasonable manner. Finally, a simulation experiment under urban dynamometer driving schedule (UDDS) settings verifies the established EMS, and the findings reveal that the suggested EMS has a lower energy consumption rate and battery deterioration rate than the rule-based method

Energy Management Strategy for Hybrid Energy Storage Electric Vehicles Based on Pontryagin’s Minimum Principle Considering Battery Degradation

The development of energy management strategy (EMS), which considers how power is distributed between the battery and ultracapacitor, can reduce the electric vehicle’s power consumption and slow down battery degradation. Therefore, the purpose of this paper is to develop an EMS for hybrid energy storage electric vehicles based on Pontryagin’s minimums principle (PMP) considering battery degradation. To verify the EMS, the hybrid energy storage electric vehicle model is first established. In the meantime, the battery cycle life trials are finished in order to develop a battery degradation model. Following that, a rule-based control approach and the PMP optimization algorithm are used to allocate power in a hybrid energy storage system (HESS) in a reasonable manner. Finally, a simulation experiment under urban dynamometer driving schedule (UDDS) settings verifies the established EMS, and the findings reveal that the suggested EMS has a lower energy consumption rate and battery deterioration rate than the rule-based method

Rational Phosphorus Application Facilitates the Sustainability of the Wheat/Maize/Soybean Relay Strip Intercropping System

<div><p>Wheat (<i>Triticum aestivum</i> L.)/maize (<i>Zea mays</i> L.)/soybean (<i>Glycine max</i> L.) relay strip intercropping (W/M/S) system is commonly used by the smallholders in the Southwest of China. However, little known is how to manage phosphorus (P) to enhance P use efficiency of the W/M/S system and to mitigate P leaching that is a major source of pollution. Field experiments were carried out in 2011, 2012, and 2013 to test the impact of five P application rates on yield and P use efficiency of the W/M/S system. The study measured grain yield, shoot P uptake, apparent P recovery efficiency (PRE) and soil P content. A linear-plateau model was used to determine the critical P rate that maximizes gains in the indexes of system productivity. The results show that increase in P application rates aggrandized shoot P uptake and crops yields at threshold rates of 70 and 71.5 kg P ha^-1 respectively. With P application rates increasing, the W/M/S system decreased the PRE from 35.9% to 12.3% averaged over the three years. A rational P application rate, 72 kg P ha^-1, or an appropriate soil Olsen-P level, 19.1 mg kg^-1, drives the W/M/S system to maximize total grain yield while minimizing P surplus, as a result of the PRE up to 28.0%. We conclude that rational P application is an important approach for relay intercropping to produce high yield while mitigating P pollution and the rational P application-based integrated P fertilizer management is vital for sustainable intensification of agriculture in the Southwest of China.</p></div

Soil Olsen-P in the top 20 cm layer of the maize strip at maize harvest (M) and the wheat-soybean strip at soybean harvest (W-S) in the W/M/S system as affected by P application rates each year.

<p>Different lower-case letters indicate significant difference (<i>P</i><0.05) by LSD between different years under the same P application rate. Different capital letters indicate significant difference (<i>p</i><0.05) by LSD between different P application rates. F = the first year (2011), S = the second year (2012), T = the third year (2013). P₀, P₁, P₂, P₃, P₄ indicate the P treatments (as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0141725#pone.0141725.t002" target="_blank">table 2</a>). Each value was the mean ± SE. Bars indicate standard errors.</p

Soil Olsen-P of the maize strip at maize harvest (A) and the wheat-soybean strip at soybean harvest (B) in the 0–100 cm layers of the soil profile in 2013.

<p>The floating bars indicate LSD (<i>p</i><0.05) between different P application rates. P₀, P₁, P₂, P₃, P₄ indicate the P treatments (as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0141725#pone.0141725.t002" target="_blank">table 2</a>). Each data point was the mean of four replicates.</p

P application rates for wheat, maize and soybean in the W/M/S system (kg P ha^-1 year^-1).

<p>P application rates for wheat, maize and soybean in the W/M/S system (kg P ha^-1 year^-1).</p

Grain yield as affected by P application rates in 2011, 2012 and 2013.

<p>A, Wheat; B, Maize; C, Wheat-soybean strip; D, W/M/S system. Each data point was the mean of four replicates.</p

Diagram showing the arrangement of wheat intercropped with maize (A) and maize intercropped with soybean (B) in the field plot.

<p>Diagram showing the arrangement of wheat intercropped with maize (A) and maize intercropped with soybean (B) in the field plot.</p