Efficient energy conversion in low-voltage applications has gained more attention due to increasing energy costs and environmental issues. Accordingly, three-level converters have been discussed as an alternative to the standard two-level voltage-source converter because they offer an increased efficiency at higher switching frequencies. From a system perspective, the benefits of using three-level converters are not only limited to the converter itself, but there are additional positive impacts on the surrounding such as on the load machine losses or on the electromagnetic interference input filter volume. In this paper, a holistic comparison of advanced three-level topologies against the two-level topology is given. Simple analytical calculations and measurements show the benefits and the optimization potential concerning several aspects, such as the necessary semiconductor chip area, the harmonic losses in the load machine and in filter components, and the volume of passive components.

Comparative Evaluation of Advanced Three-Phase Three-Level Inverter/Converter Topologies Against Two-Level Systems

The construction sector delivers the infrastructure and buildings to the society by consumption large amount of unrenewable energy. Consequently, this consumption causes the large emission of CO2. This paper explores and compares the level of CO2 emission caused by the construction activities globally by using the world environmental input-output table 2009. It analyses CO2 emission of construction sector in 40 countries, considering 26 kinds of energy use and non-energy use. Results indicate: 1) the total CO2 emission of the global construction sector was 5.7 billion tons in 2009, contributing 23% of the total CO2 emissions produced by the global economics activities. 94% of the total CO2 from the global construction sector are indirect emission. 2) Gasoline, diesel, other petroleum products and light fuel oil are four main energy sources for direct CO2 emission of global construction sector. The indirect CO2 emission mainly stems from hard coal, nature gas, and non-energy use. 3) The emerging economies cause nearly 60% of the global construction sector total CO2 emission. China is the largest contributor. Moreover, the intensities of construction sector’s direct and indirect CO2 emission in the developing countries are larger than the value in the developed countries. Therefore, promoting the development and use of the low embodied carbon building material and services, the energy efficiency of construction machines, as well as the renewable energy use are identified as three main pivotal opportunities to reduce the carbon emissions of the construction sector.

Carbon emission of global construction sector

Effects of different coolants and cooling strategies on the cooling performance of the power lithium ion battery system: A review

https://www.zenodo.org/record/2642457/files/A%20review%20on%20various%20temperature-indication%20methods%20for%20Li-ion%20batteries.pdf

A review on various temperature-indication methods for Li-ion batteries

A novel temperature-compensated model for power Li-ion batteries with dual-particle-filter state of charge estimation

Analysis of electro-hydraulic lifting system's energy efficiency with direct electric drive pump control

Effective heat transfer and protection against high operating temperatures are important, lifetime-affecting items in the design and operation of batteries, especially those intended for hybrid mobile working machines, where the peak power and current demands are high. This paper describes a methodology for the modeling of the electrical and thermal behavior of lithium ion pouch cells for hybrid mobile working machines. The model is produced by coupling the equivalent electrical circuit of the pouch cell and the 3-D pouch cell thermal model. The temperature dependence of the battery operation parameters is added to the model in order to analyze the influence of temperature on heat generation during battery operation. Determination of the parameters of the thermal model is carried out empirically based on the presented methodology, which allows the construction of a 3-D thermal model of a pouch cell without requiring detailed information about the battery chemistry. The validity of the modeling procedure is demonstrated experimentally for a 60 Ah lithium titanate pouch cell.

Three-Dimensional Thermal Model of a Lithium Ion Battery for Hybrid Mobile Working Machines: Determination of the Model Parameters in a Pouch Cell

The energy efficiency of an electro-hydraulic forklift is significantly improved by using a permanent-magnet-synchronous-motor-servo-drive-based direct pump control to control the position of the fork without control valves. This paper provides a short evaluation of the hydraulic system and a more detailed analysis of the losses of the electric machine drive system. A theoretical approach is taken and the results are verified by practical measurements. Finally, possible improvements of the energy efficiency in the suggested system are discussed.

Permanent Magnet Synchronous Machine Sizing: Effect on the Energy Efficiency of an Electro-Hydraulic Forklift

Storage of energy recovered from an industrial forklift

Powertrain electrification continues to be a growing trend in vehicular applications. Electric powertrains have numerous advantages over traditional mechanical and hydraulic powertrains but there are still important challenges to overcome for long-term commercial success. This research presents a technological assessment of present and future developments of powertrain electrification in non-road mobile machinery (NRMM). The challenges and opportunities of NRMM electrification are described in detail. The trends and drivers related to technological development such as regulations, policies and market development are analyzed, and technology enablers are highlighted. Future scenarios are formulated based on the prevailing trends and drivers, development of key components, scientific literature and status of the non-road mobile machinery industry. Some recommendations are also given in relation to the development of hybrid and electric powertrains for NRMM. The key findings of this research indicate that the electrification of NRMM is slowly started and the progress is demonstrated by hybridization of some specific, successful mobile machines. In short-term, high component and technology development costs remain the main barrier for higher adoption of electric and hybrid powertrains. In the long-term scenario, many NRMM can operate autonomously and powertrain electrification has become mainstream technology.

/pdf/overview-of-powertrain-electrification-and-future-scenarios-4u5ynb39e5.pdf

Lasse Laurila

Papers

Analysis of electro-hydraulic lifting system's energy efficiency with direct electric drive pump control

Three-Dimensional Thermal Model of a Lithium Ion Battery for Hybrid Mobile Working Machines: Determination of the Model Parameters in a Pouch Cell

Permanent Magnet Synchronous Machine Sizing: Effect on the Energy Efficiency of an Electro-Hydraulic Forklift

Storage of energy recovered from an industrial forklift

Overview of Powertrain Electrification and Future Scenarios for Non-Road Mobile Machinery