With a potential to facilitate the integration of renewable energy into the electricity system, electric drive vehicles may offer a considerable flexibility by allowing for charging and discharging ...when desired. This paper takes the perspective of an aggregator that manages the electricity market participation of a vehicle fleet and presents a framework for optimizing charging and discharging of the electric drive vehicles, given the driving patterns of the fleet and the variations in market prices of electricity. When the aggregator is a price-taker the optimization can be stated in terms of linear programming whereas a quadratic programming formulation is required when he/she has market power. A Danish case study illustrates the construction of representative driving patterns through clustering of survey data from Western Denmark and the prediction of electricity price variations through regression on prices from the Nordic market. The results show that electric vehicles provide flexibility almost exclusively through charging. Moreover, the vehicles provide flexibility within the day but only limited flexibility from day to day when driving patterns are fixed.
Traditional electric excavator only uses the electric machine to replace the engine and simulate its original working mode, which will not give full play to the advantages of the electric drive ...technology and result in poor control performance as well as low energy efficiency. In this paper, a load sensing system based on displacement adaptive and variable speed control is proposed for electric excavator to extend the flow matching range of power train system and satisfy the flow demand under different load conditions. Furthermore, a novel control strategy based on the hierarchical differential pressure control is studied. Through the control strategy, the novel load sensing system can adjust the load sensing pressure difference in stages without mutual interference, so as to maintain the power train system operation in high efficiency area, and reduce the energy loss of the valve. To verify the feasibility of the system and control strategy, the simulations and experimental test are carried out. The results show that the system and control strategy can improve the control performance effectively. The energy consumption can be also decreased by 19%–70%.
•The electric excavator powered by the battery is studied.•A load sensing system with displacement adaptive and variable speed is proposed.•A wide flow regulation range, variable differential pressure control is obtained.•It can realize the flow self-matching of the whole variable range.•It can reduce the energy consumption of the system by 19%–70%.
Finite-control-set model predictive control (FCS-MPC) has many advantages in electric drive control systems but needs the accurate knowledge of the system parameters. The performance of the FCS-MPC ...will be deteriorated under parameter mismatches. This study proposes an adaptive FCS-MPC current control method for interior permanent magnet synchronous machine (IPMSM) drives subject to the inductance variations. The inductances are identified online by an adaptive observer with a recursive algorithm, which is inherently incorporated into the FCS-MPC control process to reduce the additional computational cost. Compensation methods are also proposed to improve the identification accuracy. The simulation and experimental results validate that, the IPMSM current control performance, speed-extension capability and drive efficiency are all improved by the proposed method.
The article substantiates the necessity of identifying the dynamics of asynchronous electric drives with frequency control. It is proposed to use nonlinear transfer functions and the formula of a ...family of frequency responses of an electric drive, depending on the frequency of the stator voltage and slip. Experiments and simulations confirming theoretical conclusions are presented. The frequency responses of the drive of the stand calculated by the proposed method allowed to explain those problems of frequency control that were not explained by traditional methods - analytical, vector diagrams, substitution schemes, etc. This same technique allowed us to formulate a structural correction of the asynchronous electric drives. In contrast to the previously published research materials of asynchronous electric drives, a detailed qualitative analysis of the obtained nonlinear frequency responses and the interrelation of these characteristics with experimental results is shown for the first time in the article.
•Proposed an innovative framework with matched control strategies for loop of electric drive.•Comparing performance differences between two frameworks of loop of electric drive.•Realized refined ...thermal management targets of cooling loop of electric drive.•Reduced energy consumption of pump and fan.
This paper proposed an innovative thermal management framework and its control strategies for the cooling loop of electric drive to achieve a more refined thermal management. To investigate the performance of this method used in EVs, the proposed innovative framework model and the conventional framework of the cooling loop of electric drive were developed in KULI based on the heating principle and heat transfer theory. And the rule-based control strategies were established in MATLAB/Simulink, which was set as a controller to regulate fan, pump and proportional valve. Then, the cooling performance and the energy consumption of the two frameworks were compared through co-simulation under steady-state and transient conditions of high temperature. The results showed that this method has a better performance in temperature control of key components (exit temperature of motor is reduced by at least 5.0 °C under 3 steady-stage simulation conditions) and improved efficiency of the pump (from 6.4% to 10.1% in mode 1, from 15.2% to 23.6% in mode 2, and from 21.4% to 36.8% in mode 3), which is useful to achieve long lifetime and high efficiency of electric vehicles.
A method for adjusting frequency-regulated drives with the synchronous reluctance machine with independent excitation is proposed using the KhPT-250 cold tube reducing mill and traction drive of a ...Gazelle-Next electric vehicle as example; the method consists in independent adjustment of the phase currents with the subsequent identification of parameters of the control object by methods of frequency identification. It has been shown that, with independent control of the excitation currents and the anchor reaction, the cross links between phase current control loops can be neglected, which can be accounted for by the large bandwidth of the uniform pass-through frequency of the phase current control loops and the weak influence of phase windings located in the interpolar gap on the operation of the phase windings that currently located above the pole. It has been shown that when the drive operates at high speeds, a significant decrease in the proportionality coefficient between the magnitude of the electromagnetic moment and current is observed, which is explained by the finite speed of the phase current control loop. When adjusting the electric drive control system with dual-zone speed control, it has been suggested to introduce a correction for the anticipatory effect of the phase current in order to provide a constant relationship between the anchor component of phase current and the magnitude of electromagnetic moment.
The AC drive is an important component and the most common element of any manufacturing process. A particularly serious task is the proper assessment of the AC drive’s technical condition, as its ...failure can cause problems for entire units and complexes of industrial enterprises. At present, there are several approaches either to determine electric drives’ condition or to find certain defects. Frequently, these methods require the installation of additional equipment that exceeds the price of the electric drive by several times. In this work, a simple approach is proposed. It includes the use of a diagnostic curve to assess the condition. This diagnostic curve is produced from the measurement results of the current sensors on the drive. Based on the Park vector modification, this is a simple and affordable way to obtain real-time information. The obtained curve can be used for the following purposes: directly for condition assessment by visual monitoring, as a sign for diagnostic systems built on artificial intelligence methods, for dynamic tuning of the drive control system. The article gives the algorithm for obtaining the diagnostic curve, showing its efficiency for model and field experiments. In model experiments, the faults in the rotor and stator of the drive were simulated; in field experiments, the state was analyzed by changing the load on the motor.
•Designed a versatile GNSS simulator for multi-mode experiment, along with its corresponding control unit and experimental bench.•Quantitatively analyzed seeding quality of five motors in different ...seeding modes and speeds.•Analyzed the applicability of five motors and future research directions.•Basic characteristics of an electric-drive seed-metering system dedicated to seeding were presented.
The Electric-drive Seed-metering System, crucial for precision seeding, has been enhanced by digital and electronic controls, improving efficiency and reducing seed waste. However, Electric-drive Seed-metering System’s research faces challenges like the absence of quantitative motor performance comparisons and outdated evaluation protocols. Despite advances beyond GNSS-based seeding to include techniques like Variable-Rate Seeding and Automatic Section Control, traditional tests fail to reflect actual seeding conditions accurately, making it challenging to precisely identify the issues present in the system, thereby creating obstacles for its optimization, making it hard to enhance seed utilization during the seeding process and improve the quality of it. In response to these issues, five commonly used motors with similar performance were selected to construct different ESS in combination with air-suction seed-metering device. A GNSS simulator was designed using the STM32F103C8T6 chip, capable of fully simulating different operational scenarios. The STM32F407ZGT6 was used in conjunction with a photoelectric seed sensor to design the main controller, allowing real-time monitoring of seeding status data via an LCD display. A torque sensor array was also incorporated to assess the seeding performance of different motors under various torque disturbances. Various experiment indices such as the quality index, seed-spacing coefficient of variation were employed for a comprehensive and systematic evaluation of the different ESS. And after the overall experiments, ANOVA and Tukey tests were employed to further quantify and validate the operational states of different motors under various modes and speeds. In fixed speed mode, at speeds up to 15 km·h−1, open-loop stepper motor ceased operation, while other motors averaged an 92.83 % quality index, led by closed-loop stepper motor at 95.37 %. Under speed with noise, closed-loop stepper motor 's quality index and seed-spacing coefficient of variation worsened by only 4.06 % and 10.66 %, outperforming others. In turn compensation mode, closed-loop brushed motor and BLDC with hall encoder recorded lower quality index of 85.18 % and 86.70 %, respectively, compared to BLDC with optical encoder’s 97.02 %. With Automatic Section Control active, closed-loop brushed motor showed a marked increase in seed errors at higher speeds, whereas closed-loop stepper motor maintained high accuracy with only 1 missed seed and 7 multiple seeds. The results indicate that brushed motors perform worse in high-speed response and low-speed stability compared to stepper motors. Open-loop stepper motors operate stably but are not suitable for high-speed seeding. BLDC motors are not the best choice for electric-drive seeding in terms of price and precision, and if the disturbance resistance of closed-loop stepper motors can be improved, these motors have the potential for widespread application in the future.
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.
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