Power Transmission Device Research Articles

Electric transmission for hybrid vehicle

A technical solution is proposed for the electrical transmission of the torque of the internal combustion engine to the wheels (propeller) of a hybrid vehicle to set it in motion. The purpose of the technical solution is to reduce energy losses in the electrical power transmission device and reduce the cost of its implementation. The expected economic effect in the implementation of the proposed technical solution consists of a reduction in power losses during electric power transmission up to 10% of the engine power, and the cost of its implementation will reduce the cost of the vehicle by up to € 2 000. The proposed device is technically feasible using commercially available devices and can be used in the automotive industry, while being able to recoup the costs of implementation, that is, it meets the criterion “industrially applicable”.

Modelling of elastoplastic, multi-scale and multi-contact problems: application to worm gears

A nonconventional application of worm gears exploits the irreversibility of these power transmission devices in order to realize fast emergency braking. This application can be used to secure lifting devices. A limiting factor in the design of these instantaneous braking systems is the residual deformations of the worm/wheel contacting teeth, due to the impact between them at each emergency stop. The prediction of these residual displacements requires solving of an elastic–plastic, multi-scale and multi-contact problem. Original numerical tools were developed in this study to solve the problem at global and local scales. The method has been validated by comparing the obtained results with 3D measurements on new and deformed worm/wheel pairs. In order to predict the issue of the worm gear after an impact, a criterion based on kinematic errors is proposed. Applying this criterion gives the maximal admissible torque for the braking system to be operational after the impact.

Adaptive control strategy of solid state transformer with fast dynamic response and enhanced balance performance

Solid state transformer (SST) is designed as a power transmission device between AC grids and DC grids. However, the power fluctuation causes unbalanced power sharing among dual active bridge (DAB) converters and large voltage fluctuations on dc buses. Here, an adaptive virtual impedance control (AVIC) strategy is proposed to improve the balance performance of SST. Adaptive virtual impedance controller gets the same dynamic response for DAB converters, which matches dynamic impedance of DAB converters. Thereby the power balance can be achieved even the load changes. Meanwhile, an adaptive feedforward control scheme is proposed to reduce the influence of load fluctuation on DC bus voltage. The adaptive feedforward scheme also considers the parameter mismatch, thereby the balance of SST will not be destroyed. Moreover, the balanced power sharing achieved by adaptive controller eliminates the difference between actual transmission power and compensation power in each rectifier, which further suppresses the intermediate capacitor voltage fluctuations. Finally, simulation and StarSim experimental results verified the correctness and effectiveness of the proposed control strategy.

A compact high-power microwave TM01-TE01 mode converter

In circular waveguides, the TE01 mode has the lowest transmission loss, which is very suitable for long-distance transmission of high-power microwaves (HPMs). The output mode of HPM sources is mainly the TM01 mode; however, there are few research studies on mode converters of TM01-TE01. In this paper, a high efficiency HPM TM01-TE01 mode converter is designed; compared with the traditional TM01-TE01 mode converters, the structure of the mode converter is compact and easier to process. It is mainly composed of an input circular waveguide, a tapered rectangular waveguide, a 90° bent rectangular waveguide, and an output circular waveguide. A prototype with a center frequency of 2.4GHz is fabricated and HPM experiments are carried out. The transmission efficiency of this device reaches 99.8% in the simulation, and the measured transmission efficiency is more than 98%. Additionally, the measured power handling capacity is more than 1 GW, which is consistent with simulation. This designhas important reference significance for the designof long-distance power transmission devices and HPM mode converters.

Research on Vehicle Control System of Construction Machinery Based on Machine Vision

With the continuous development of construction machinery technology, great breakthroughs have been made in the application of electronic information technology. The control and operation system of construction machinery vehicles refers to the system that applies and receives certain instructions and makes the construction machinery produce specified actions according to the requirements of operators through its power transmission device. Compared with the previous construction machinery, the developing construction machinery has made good achievements in high efficiency, intensification, cost saving and environmental protection. The traditional speed measuring method can not meet the requirement of measuring accuracy of actual walking speed of construction machinery, and can not accurately reflect the actual walking speed and instantaneous motion state of construction machinery. This paper analyzes a kind of construction machinery vehicle using machine vision. It obtains important information through image processing, adopts intelligent control technology based on machine vision as an important control means of power drive, and can judge and control driving according to road conditions, thus improving the accuracy and stability of industrial autonomous transportation..

Experimental Study of CVT for Improving Belt Life by Analyzing the Thermal properties of Sheave Material

The CVT or Continuously Variable Transmission is a power transmission device used as a mode of Automatic transmission system with a continuum range of gearing ratios due to its cam-ed sheave design. There are several different design other than conically sloped pulley system, but all of them work on same principle. Previous studies and applications have looked into the problem of heating of the CVT sheaves and belt which has led to reduction of transmission efficiency and reduction of belt life as well as life of sheaves and other parts. Mainly two reasons behind this phenomenon - first, the practical and commercial CVT is far from ideal and has belt slippage in general working environment and then second from this dynamic friction, higher temperatures are observed which in return causes more slippage especially in case of rubber belt which is the most widely used type. After software analysis, choose a thermally best material for the sheaves as a result of the analysis and manufacture a custom CVT and a test rig for it. Thus, finally the testing of such practical apparatus would suggest true results and confirmation to the hypothesis as well as compiling data about the test, equipment working and hurdles in practicality and commercial transformation of the project. In closure, the objective is improvement of CVT belt life by customizing the sheave material of the CVT.

Overview of Subsynchronous Oscillation in Grid-connected Wind Farm

Background: Over the past few years, the subsynchronous oscillation (SSO) caused by the grid-connected wind farm had a bad influence on the stable operation of the system and has now become a bottleneck factor restricting the efficient utilization of wind power. How to mitigate and suppress the phenomenon of SSO of wind farms has become the focus of power system research. Methods: This paper first analyzes the SSO of different types of wind turbines, including squirrelcage induction generator based wind turbine (SCIG-WT), permanent magnet synchronous generator- based wind turbine (PMSG-WT), and doubly-fed induction generator based wind turbine (DFIG-WT). Then, the mechanisms of different types of SSO are proposed with the aim to better understand SSO in large-scale wind integrated power systems, and the main analytical methods suitable for studying the SSO of wind farms are summarized. Results: On the basis of results, using additional damping control suppression methods to solve SSO caused by the flexible power transmission devices and the wind turbine converter is recommended. Conclusion: The current development direction of the SSO of large-scale wind farm grid-connected systems is summarized and the current challenges and recommendations for future research and development are discussed.

Design and analysis of wireless power transmission devices for multi-degree-of-freedom actuator applications

ABSTRACT The multi-degree-of-freedom actuator is commonly used in the field of bionics, and a wireless transmission device with visual image acquisition devices is the best choice for the power transmission. For the wireless power transmission system, to offset the problem of reduced power and efficiency at the receiving end, this paper designs a wireless charging device for this kind of multi-degree-of-freedom actuator application. The S 21 parameters, magnetic flux density, and efficiency of the wireless charging device under different rotation angles are calculated and simulated by finite element analysis. Finally, the accuracy of the simulation and the effectiveness of power transmission are verified by experiments.

Optimization of power flow through facts in electrical networks

A mathematical model is presented for optimizing power flows in an electric network with a flexible controlled alternating current power transmission device - FACTS. The range of questions on the problem of optimizing the power flow in electric networks with one of the FACTS devices, the SVC static power factor compensator, has been expanded and investigated. The Lagrange function for the SVC device is proposed, which serves as the basis for obtaining a linearized equation and determining the optimum of the objective function.The method and algorithm of the optimization problem in the electric power system containing devices of the FACTS technology have been synthesized. The mathematical model allows for flexible and reliable optimization of the electrical power system. Flexibility is explained by the universality of the model, and reliability is explained by the high convergence rate of the Newton method used.

Dynamic rating assists cost-effective expansion of wind farms by utilizing the hidden capacity of transformers

Dynamic rating of power transmission devices is a technology that allows better equipment utilization through real-time monitoring of the weather conditions and the load. Dynamic rating of transformers is a fairly new technology if compared to the dynamic rating of power lines, and has a high potential for significantly improving component utilization while lowering investment costs on installing new transformers.The following work investigates how to utilize already operational transformers, which are used for wind farm connection, for expanding wind generation capacity. Also, this paper shows improvements that dynamic transformer rating can bring to both power grid operators and wind farm owners by exploring the economic benefits of expanding wind parks without investing in new power transformers. Connecting additional wind turbines at sites with high wind potential after the wind park is already in exploitation can assist in lowering electricity price and provide a possibility of less risky investment in the wind energy sector. This paper uses transformer thermal modelling and wind farm expansion techniques such as convolution method and product method to investigate to which extent existing wind farms can be expanded using already installed transformer units.Five transformer locations and nine units are studied for finding the potential of dynamic transformer rating for network expansion applications. The analysis shows that the optimal expansion of wind power from a generator perspective is around 30% to 50%, although, it can be limited further by network restrictions. A possibility to use a large component, such as power transformer, closer to its full potential can provide material and cost savings for building new devices and decrease investment costs on manufacturing, transportation and installation of new units. Dynamic rating of power transformers can also increase the socio-economic benefits of renewable energy by lowering electricity price from renewables and incentivize an increased share of green power in electricity markets.

Torque and rotational speed sensor based on resistance and capacitive grating for rotational shaft of mechanical systems

Torque and rotational speed are important parameters to characterize the power of rotating parts for mechanical systems, so a rotational shaft’s torque and rotational speed sensing method and real-time signal processing are key technologies for mechanized equipment, such as vehicles, ships, etc. Hence an advanced torque and speed sensing technology and a data processing technology are very important for improving the performance of mechanical equipment. However, the power transmission device’s rotational shaft has a compact structure and narrow space, so it is difficult to install a signal transmission and power supply device of a sensor on the rotational shaft. To solve these difficult problems, this paper proposes a rotational shaft torque and rotational speed measurement method coupling resistance and capacitance. This method uses two resistance strain gauges and a capacitive grating, and the capacitive grating transmits signals in a non-contact coupling manner. The sensor on the rotational shaft needs no power supply and the signals are transmitted to a measurement circuit from a stationary sleeve, so this method essentially solves the difficult problems in signal transmission and power supply. Simulation and measurement experiments show that the resistance strain gauges obtain information and the capacitive grating sensor transfers information. The method coupling resistance and capacitance for realizing information sensing is feasible, which is suitable for measuring the torque and rotational speed of the rotational shaft of mechanical equipment in spite of the compact structure and narrow space.

Tribology Related to Power Transmission Devices for Electric Vehicles

Tribology Related to Power Transmission Devices for Electric Vehicles

Improved design and experimental verification of linear magnetic gear using parametric analysis

This study aims at improving the design of a linear magnetic gear (LMG) and verifying its reliability using a fabricated prototype. LMGs represent electromechanical energy-conversion machines employing permanent magnets (PMs). However, given the linear structure of power-transmission devices, LMGs are difficult to manufacture. The proposed study presents an LMG-design aimed at facilitating ease of its manufacturing. To this end, the PM-ratio performance was first analyzed for selection of an appropriate basic model, which can be subsequently optimized by changing the PM-shape and flux-modulation poles to realize optimum electromagnetic characteristics. Moreover, mechanical characteristics of the optimized model were analyzed to aid fabrication. Results of finite-element analyses and experiments performed in this study on a fabricated prototype demonstrate the reliability of the proposed model.

Design and Experimental Study of Non-contact Power Transmission Device in Static Push-type Rotary Steering Drilling System

For improvement of contactless power transformer which is used in rotary steering system, this paper uses simulation method to study on the influence of the shape of the ferrite, the number os turns and installation position on the efficiency and power of the contactless power transformer. As well as, the author take several test to study the influence of environment, fixed position, etc. on this equipment and the regularity of power and efficiency. The research shows that the contactless power transformer is competent for rotary steering system, and the axial installation error impact the transmission efficiency and power which has the most power and efficiency at -3mm axial fixed position and ±3mm fixed position error can meet the rotary steering system requirements.

UAV Transmission Line Inspection Object Recognition based on Mask R-CNN

Currently, unmanned aerial vehicles (UAV) are applied to routine inspection tasks of power transmission devices. Deep-learning algorithm and machine vision have attracted much attention in the field of the UAV’s autonomous control as it’s an effective way to improve the efficiency of inspection. Considering the differences between the distant and close view, this paper adopts Mask R-CNN to detect various components of power transmission devices but use the methods such as processing of the edge, hole filling and Hough Transform identify the wires in distant. Some major components, such as pole, truss, cross arm, insulator string and so on, can be 100% recognized. This proposed model shows the characteristics of high recognition speed and high accuracy, which can assist UAV to inspect well.

Investigation into the structure and transmission mechanism of a novel multistage face gear transmission based on battery discharge current constant of an electric vehicle

The performance and mileage of an electric vehicle (EV) are usually affected by battery capacity and transmission efficiency. We propose a novel power transmission device, which matches the dynamic performance of a vehicle under limited conditions, such as motor peak power and battery capacity, to ensure working in the constant battery discharge current and high efficiency. Based on the constant current discharge principle of power battery, aiming at the long driving distance of EV, the optimisation design model of structural parameters is established to yield the best transmission ratio and optimal detailed design parameters. We optimised the ADVISOR simulation to verify the speed regulated performance and drive efficiency of the whole transmission system.

Compensation Topologies in IPT Systems: Standards, Requirements, Classification, Analysis, Comparison and Application

Wireless power transfer devices are becoming more relevant and widespread. Therefore, an article is devoted to a review, analysis and comparison of compensation topologies for an inductive power transfer. A new classification of topologies is developed. A lot of attention is paid to the problems of the physical fundamentals of compensation work, standards, safety, and five main topology requirements. It is determined, that topologies with the series primary compensating are the most effective in the IPT for charging devices among the four classical schemes. The series-parallel solution is recommended in case of the low output voltage, minimum size of a secondary side coil is achievable. The series-series solution does not depend on the magnetic coupling coefficient and the load on the resonance frequency. For the convenience of displaying and understanding the information, the comparison results are listed in the tables, graphs and dependencies. The main suitable topologies for a certain application are defined. The given conclusions provide a “one-stop” information source and a selection guide on the application of compensation topologies both in terms of devices and in terms of power level that is the main value of this paper. During literature analysis and recent trends in the market for wireless power transmission devices, the main possible further ways of developing topologies are underlined. First of all, it concerns increasing the frequency of resonance of compensation topologies, the use of multilevel / multi-pulse / multicoils structures, the study of existing high-frequency semiconductors and the development of the semiconductor and magnetic materials.

Low cost of sustainable work and maintenance for offshore wind power speed-increasing device

For the problem of wind turbine outage caused by the failure of wind power transmission devices, we proposed an offshore wind power transmission device with low sustainable operation and low maintenance cost. Through the combination of gearbox A and B, the power transmission of the offshore wind turbine is uninterrupted, and the continuous operation of grid-connected power generation enhances the economic benefits of offshore wind turbines. The maritime maintenance man-hours is reduced by moving the speed increase gearbox A from the offshore wind turbine site to the land for maintenance inspection, and the maintenance cost is significantly reduced.

A Hybrid Building Power Distribution System in Consideration of Supply and Demand-Side: A Short Overview and a Case Study

As the quantity of direct current (DC) load and wireless power transmission (WPT) devices are continuously increasing in building, in order to efficiently utilize renewable energy (which outputs DC power) such as photovoltaic (PV), especially for building integrated photovoltaic (BIPV), and regeneration energy from elevators (which also outputs DC power), a novel building power distribution system architecture is explored in consideration of the characteristics of supply and demand-side in this paper. The proposed architecture is a hybrid framework integrated with conventional alternating current (AC) power distribution system, DC power distribution and WPT system. The applied AC and DC hybrid power distribution system has higher conversion efficiency than a single AC power system, which indicates that the former is becoming an important trend of building power distribution. In addition, the results of experimental test in a case study suggest that the proposed architecture can provide fine service for efficient application of renewable energy and regeneration energy in building. The obtained results also can serve as a foundation to promote the development of building power distribution system and related practical application in building.

Nonsmooth Vibration Characteristic of Gear Pair System with Periodic Stiffness and Backlash

As the most widely used power transmission device in mechanical equipment, the vibration characteristics of gears have a very important influence on the working performance. It is of great theoretical and practical significance to study the vibration characteristics of gear system. In this paper, a gear transmission system model is set up in a forcefully nonlinear form; the continuity mapping and discontinuity mapping are utilized to analyze the nonsmooth vibration. Then, the sliding dynamics of separation boundaries is studied by using the perturbation method and the differential inclusion theory. In addition, the periodic response of gear pair system is illustrated and Floquet’s theory is presented to confirm the stability and bifurcation of periodic response. Concurrently, the maximal Lyapunov exponent is obtained to accurately determine the chaotic state in gear pair system, which is consistent with the bifurcation diagram and Poincare section. Finally, a reasonable explanation is given for the jump phenomenon in bifurcation diagram.