To simplify the layout of a purely electric vehicle transmission system and improve the acceleration performance of the vehicle, this paper utilizes the characteristics of the large torque of a hydraulic transmission system and proposes a new mechanical–electric–hydraulic dynamic coupling drive system (MEH-DCDS). It integrates the traditional motor and the swashplate hydraulic pump/motor into one, which can realize the mutual conversion between the mechanical energy, electrical energy, and hydraulic energy. This article explains its working principle and structural characteristics. At the same time, the mathematical model for the key components is established and the operation mode is divided into various types. Based on AMESim software, the article studies the dynamic characteristics of the MEH-DCDS, and finally proposes a method that combines real-time feedback of the accumulator output torque with PID control to complete the system simulation. The results show that the MEH-DCDS vehicle has a starting time of 4.52 s at ignition, and the starting performance is improved by 40.37% compared to that of a pure motor drive system vehicle; after a PID adjustment, the MEH-DCDS vehicle’s starting time is shortened by 1.04 s, and the acceleration performance is improved by 23.01%. The results indicated the feasibility of the system and the power performance was substantially improved. Finally, the system is integrated into the vehicle and the dynamic performance of the MEH-DCDS under cycle conditions is verified by joint simulation. The results show that the vehicle is able to follow the control speed well when the MEH-DCDS is loaded on the vehicle. The state-of-charge (SOC) consumption rate is reduced by 20.33% compared to an electric vehicle, while the MEH-DCDS has an increased range of 45.7 m compared to the EV. This improves the energy efficiency and increases the driving range.

The hydraulic accumulator has the advantages of high power density, fast response, stable operation and high cost performance. However, compared with the electric energy storage method, the hydraulic accumulator has low energy density and large pressure fluctuation while absorbing and discharging energy, which severely limits its application in hydraulic excavators. To improve the potential energy loss of the boom during the lowering process, an electro-hydraulic drive and energy recovery system for excavator booms (EHDR-EEB) based on a battery and accumulator is proposed. As a result, a simulation model of the electro-hydraulic drive and energy management strategy of a 1.6 t pure electric hydraulic excavator is built to investigate the energy regeneration and utilization. The simulation outcomes show that the potential energy recovery rate is as high as 92%. This research on EHDR-EEB makes a significant contribution to the economic improvement of electric hydraulic excavators.

Focused on the troubles and defects introduced by the traditional single form of electric vehicle transmission, this paper proposes an electro-hydraulic power coupled electric vehicle based on the working principle of an electro-hydraulic power integrated drive system for light-duty cargo vehicles. The integration of the planetary row into the drive system allows the interconversion of mechanical, electrical, and hydraulic energy. By describing the system structure and composition, several working conditions during automobile driving are proposed, and the working principle of every circumstance is introduced. Simultaneously, the article determines the preliminary optimal ratio with the battery’s state of charge (SOC) as the constraint. Then, the orthogonal test matrix of electro-hydraulic ratios and speed thresholds for each operating condition is established according to Taguchi’s method. The impact of each optimized parameter on the motor torque and hydraulic torque as well as the SOC and the proportion of the effect is evaluated by the simulation to obtain the optimal solution. The simulation consequences show that the motor torque and hydraulic torque are reduced, and thus, the vehicle’s acceleration performance and energy recovery efficiency are improved.

Optimizing control rate parameters is one of the key technologies in motor control systems. To address the issues of weak robustness and slow response speed in traditional adaptive control strategies, an adaptive control system based on sliding mode control is proposed to enhance the overall performance of permanent magnet synchronous motors. The Non-dominated Sorting Genetic Algorithm II and Multi-objective Particle Swarm Optimization are employed to effectively optimize control parameters, thereby mitigating motor torque and speed overshoot. A Partial Sample Shannon Entropy Evaluation method, leveraging entropy theory in conjunction with the Z-score method, is introduced to facilitate the feedback regulation of the optimization process by assessing motor output torque. Simulation results confirm that the proposed control strategy, in combination with the optimized control rate parameters, leads to substantial improvements in motor performance. Compared to traditional adaptive control strategies, the proposed approach improves the motor’s steady-state response speed by 42% and reduces rotor error during system fluctuations by 23%, significantly enhancing the motor’s response speed and robustness. Following parameter optimization, speed and torque overshoot are reduced by 38% and 10%, respectively, resulting in a significant improvement in the stability and precision of the motor control system.

Against the backdrop of the rapid burgeoning of international energy engineering, the efficient utilization of energy is a paramount factor. The key idea in this paper is to propose an elliptical rotor scraper pump (ERSP) in order to address the imperfections and defects of traditional volume pumps, such as their labyrinthine design, low volume utilization efficiency and undesirable sealing performance. The ERSP can dramatically achieve the aims of ameliorating pump structure and improving energy efficiency. One of the Roots pump's rotors or the vane pump's shifting blade is replaced by a swing scraper in the ERSP. It is worth noting that a small swing range is a high-priority feature of the scraper; the scraper not only serves the purpose of dividing the pump cavity and self-sealing the unit but also reduces the noise level when working. A vital function of ERSP is the efficient conversion of mechanical energy into fluid pressure energy by changing the volume. Simultaneously, based on theoretical analysis, the mathematical model of the ERSP is established, and its kinematic characteristics are investigated, using ADAMS to verify the kinematic rationality of the ERSP. Ultimately, the research group manufactured a prototype of the pump, based on the previous simulation results and calculations, and experiments verified the feasibility of the pump. The design and research of the ERSP have essential reference significance for the development of fluid energy machinery technology.

In order to address the problems of low energy storage capacity and short battery life in electric vehicles, in this paper, a new electromechanical-hydraulic power coupling drive system is proposed, and an electromechanical-hydraulic power coupling electric vehicle is proposed based on this system. The system realizes the mutual conversion between mechanical energy, hydraulic energy, and electric energy through the electromechanical–hydraulic coupler. This paper describes the structural characteristics and working principles of the system and analyzes the different working modes during the driving of the vehicle. We established a mathematical model of the hydraulic accumulator and the hydraulic pump and motor. Based on the vehicle dynamics model, an AME Sim vehicle model was built and the vehicle, and the relevant hydraulic parameters were set in combination with the actual situation. The braking energy recovery and release process was jointly simulated by AME Sim and Simulink. The simulation results show that the hydraulic accumulator size of the accumulator volume can influence the maximum working pressure of the accumulator and the SOC of the vehicle battery, and it is verified that 35 L is the best capacity. This study has an important reference value for matching electromechanical–hydraulic coupling parameters of electric vehicles.