The electrification of construction machinery is an inevitable development trend due to strengthened restrictions on greenhouse gas and pollutant emissions from construction machinery. However, the ...widespread adoption of pure electric construction machinery is still in its infancy and faces numerous challenges. This paper introduces the latest significant contributions in the electrification of construction machinery, encompassing three dimensions: mechanical components, control strategies, and typical machines, and discusses the gaps and requirements of massive electrification in different dimensions. Lastly, the broad prospects and vast challenges of the widespread adoption of pure electric construction machinery are predicted and discussed. Additionally, the technical routes for the different type's construction machinery are analyzed, and the initiatives to promote electrification are put forward from the aspects of mechanical components, control strategies and application scenarios/business models.
•Construction machinery application scenario and mechanical structure characteristics.•Configuration of typical mechanical components in electric construction machinery.•Summarized various control strategies for construction machinery.•Typical commercial products of pure electric construction machinery.•Proposed different technical routes for pure electric engineering machinery.
In European industry, such as metallurgical, mining and processing, construction, food, and chemical, vibration exciters are used, which indicates their wide and, in some cases, unique technological ...capabilities. The most common are electromagnetic and unbalanced vibration exciters. The advantages of electromagnetic vibration exciters include the ability to control the amplitude of the vibration by changing the electrical power supplied; the disadvantages are high material consumption. However, unbalanced vibration exciters have low energy efficiency, which is associated with difficult start-up conditions and with an overestimated mechanical power of the vibration exciter in relation to the power required by the technology itself, which is due to the need to minimize the effect of the technological load on the operating mode of the vibrating unit. Adjusting the amplitude of the disturbing force of unbalanced vibration exciters, regardless of the vibration frequency, will make it possible to reduce the installed power of the unit by passing the resonant frequency with a minimum disturbing force and compensating for the effect of the process load by means of a closed-loop electric drive. In the course of the study, an analytical description of the interaction of the rotating unbalances located on a common movable platform was obtained. On the basis of these analytical dependencies, a mathematical model was developed that takes into account the dynamic characteristics of a frequency-controlled asynchronous electric drive of a closed-loop control system for the mutual arrangement of rotating unbalances. The simulation results confirmed the possibility of using the specified electric drive to control the oscillation amplitude directly in the process of operation of a four-unbalanced vibration exciter. A physical experiment was carried out to determine the transient processes of changing the angular velocity of an induction motor with an abrupt change in the frequency converter setting. On the basis of this experiment, the previously created mathematical model was refined in terms of describing the dynamic parameters of the electric drive. The proposed structure of the control system, the performance of which has been confirmed by mathematical modeling, makes it possible to implement an adjustable four-unbalanced vibration exciter using single commercially available asynchronous vibrators.
This paper is concerned with combined power-source sizing and energy management optimization for multi-motor-driven electric powertrains. Existing studies focus mostly on adopting heuristically ...determined battery and motor sizes for such powertrains, without a sufficient exploration of the coupling between power-source dimension and energy management strategy. To address this research gap, this paper aims at presenting an alternative, convex programming based method to optimize the multi-power-source integration problem, for vehicular economy maximization. Specifically, for the first time, we leverage this method to optimize an electric bus powertrain configuration with front-and-rear-axle dual motors and a clutch, as a case study. Numerous analysis results, as well as comparisons with common design/control practice, demonstrate the effectiveness and computational benefit of the proposed scheme.
The demand for alternative fueling methods to reduce the need for fossil fuels is not limited to the electrification of ground vehicles. More-electric and all-electric aircraft pose challenges, with ...extensive requirements in terms of power density, efficiency, safety, and environmental sustainability. This paper focuses on electrical machines and their components, especially for high-power applications like the main propulsion. The electrical machine is evaluated from different aspects, followed by a closer look at the components and materials to determine the suitability of the current standard materials and advanced technologies. Furthermore, the mechanical and thermal aspects are reviewed, including new and innovative concepts for the cooling of windings and for the use of additive manufacturing. Aircraft have special demands regarding weight and installation space. Following recent developments and looking ahead to the future, the need and the possibilities for light and efficient electrical machines are addressed. All of the approaches and developments presented lead to a better understanding of the challenges to be expected and highlight the upcoming opportunities in electrical machine design for the use of electric motors and generators in future aircraft. Several prototypes of electrical machines for smaller aircraft already exist, such as the electric drive of the Siemens powered Extra 330LE. The focus of this paper is to provide an overview of current technical possibilities and technical interrelations of high performance electric drives for aviation. A 1 MW drive is exemplified to present the possibilities for future drives for airplanes carrying a larger number of passengers. All presented techniques can also be applied to other drive power classes.
With global warming and the energy crisis becoming more serious, the emission regulations for construction machinery (CM) are increasingly strict. The pure electric drive system is an inevitable ...trend for CMs. Although the pure electric drive system is widely used in the industry field and some technologies have been successfully transplanted to the mobile machines, it's not easy for CMs to realize the electrification. Types of pure electric CM (PECM) are discussed firstly to give a glance at PECM. Then the characteristics of a pure electric system for CMs are introduced. Key technologies, like variable speed control of the electric motor (EM), hydroelectric EM driving, new hydroelectric actuator, power supply, and energy recovery, are analyzed in depth. The difficulties of CMs to realize the electrification by comparing the difference between the pure electric power used in CM and the pure electric power used in the other fields. Moreover, the researches and developments in the pure electric drive systems for CMs are introduced. Finally, the challenges that researchers and the CM manufacturers will face are forecasted.
•Pure electric construction machinery has four types of power supply.•The core components of the power unit of the pure electric drive system are energy storage unit and electric motor.•Key technologies of the pure electric drive system applied to pure electric construction machinery s are discussed.•Differences between the pure electric power used in construction machinery and the pure electric power used in the other fields are analyzed.•Typical prototypes of pure electric construction machinery are introduced.•The development, core components, typical prototype and challenges of pure electric construction machinery are discussed.
Model predictive control are actively used in industry in high-power electric drives, in which it is permissible to use expensive programmable logic matrices that provide calculations with a ...prediction horizon of up to ten epochs and a forecast tree of several million variants. However, the computing power of microcontrollers is not enough to implement such systems in a low-power electric drive. The development of microcontrollers is following the path of increasing not only computing power, but also memory, which makes it possible to implement model predictive control systems in practice using lookup table methods for calculating control actions for all combinations of state variables and control actions. The paper shows the possibility of designing control with prediction for two types of electric drives—a DC electric drive and a switched reluctance electric drive—as objects with a small number of state variables, which allows one to fit the precalculated lookup tables of control actions in the memory of the microcontroller. Studies on mathematical models have shown that model predictive control with a finite control set and a single prediction horizon has disadvantages due to variable switching frequency, and control with a continuous control set implemented by the lookup table method allows one to perform control calculations immediately before the start of the next pulse width modulation period, reducing the algorithm execution time by hundreds of times.
The aim of the presented paper is to introduce the reader to hardware-in-the-loop (HIL) simulation in electric drives, the motivation for its usage and its benefits. Basic information about HIL ...simulation in general and the connection to electric drives is followed by an explanation of the main principle of the dynamic emulation of mechanical loads for electric drives, which is a special case of HIL simulation. Next, the description of the three main methods of load emulation and their mathematical background are presented in the order of historical appearance: the emulation with compensator and tracking controller, the emulation based on non-linear control and the emulation with feed-forward compensation with the use of inverse dynamics.
The electric mode is the main operational mode of dual-motor hybrid electric vehicles (HEVs), so the reliability of the dual-motor electric drive system (DEDS) is particularly important. To research ...the electromechanical coupling mechanism of the DEDS of HEVs, firstly, considering the time-varying mesh stiffness of gears and the nonlinear characteristics of inverters, an electromechanical coupling dynamics model of the DEDS was established, including the permanent magnet synchronous motor (PMSM) and the gear transmission system. Then, the electromechanical coupled dynamic characteristics of the DEDS in the single-motor and dual-motor drive modes were analyzed under steady-state and impact load conditions, respectively. The results show that the motor stator current frequency is modulated by the complicated gear meshing frequency, and the operation state of the gear transmission system can thus be monitored in the stator current. Impact load causes the instantaneous torsional vibration of the transmission system dominated by the first-order natural frequency, and the vibration characteristic frequency appears in the form of a side frequency in the stator current signal; moreover, compared with the single-motor drive mode, the speed synchronization error in the dual-motor drive mode will aggravate torsional vibration in the gear system. The impact energy of the gear system caused by external impact load can be suppressed by reducing the speed synchronization error.
To improve the efficiency of construction machinery driven by pure electric power and to reduce energy consumption, a variable-pressure differential control strategy based on variable-speed control ...for a quantitative pump load-sensing system is proposed. The scheme of quantitative pump load sensing system based on variable speed control is introduced. The advantages, control objectives, and control strategies of the proposed control system are analyzed in different working conditions using simulations and experiments. The results show that the proposed variable-pressure differential control strategy can substantially reduce energy consumption. In the no-load mode, the power consumption of the proposed system was approximately 33.3% lower than that of the traditional system. During the idle mode, the proposed system consumed no energy, while the traditional system consumed about 0.6 kW. The energy saving of the main pump in the low-speed and low-flow-rate case was about 38%. In the lifting and pressure-holding case, the motor of the proposed system consumed 17.3% less power than that of the traditional system. In all test conditions, the proposed system demonstrated a good energy-saving ability. In addition, the proposed system has a high response rate and smooth operation across different working conditions, which demonstrates good control performance.
•Quantitative pump load sensing system based on variable-speed control for the electric construction machinery was proposed.•A variable-pressure differential control strategy was described.•The energy saving of the proposed system were recorded at around 17% to 62%.•The greater the pressure differential, the faster the rise in both the pressure and flowrate of the pump.
PDF
