In this paper, a rear-wheel-driven series hybrid electric vehicle which has a mechanically operated friction brake system is studied. A new cooperative control of regenerative braking and friction braking called ‘combined braking’ is proposed for this vehicle configuration. A mechanism to adjust the proportions of regenerative braking and friction braking was proposed in this paper. Further, the braking force distribution between the front wheels and the rear wheels was analysed to ensure stable braking. The brake system characteristics were considered to ensure that the driver’s feel remains the same in the new proposed combined braking strategy. The simulation results under urban driving and across the Modified Indian Driving Cycle and vehicle road testing results show that the proposed combined braking can regenerate more than twice the braking energy of conventional parallel braking. Also, with combined braking, the braking force distribution between the front wheels and the rear wheels is closer to t...

Cooperative control of regenerative braking and friction braking for a hybrid electric vehicle

An automatic fast charger station with a power level of 120 kW is developed for city Bus Line 60 in Gothenburg, Sweden. There are some power quality issues towards the utility grid during the charger operation. The aim of this paper is to explain the project and to present the measurement results with respect to power quality issues. The main specifications of the battery, charger, charging infrastructure and bus route are explained. The measurement results show that the harmonic emission is within the prescribed limit despite the high amount of low-frequency harmonics because of a passive diode rectification. It is suggested to replace the passive diode rectifier with an active front-end converter to eliminate low order current harmonics and to obtain a unity power factor operation. The main contribution of this work is to demonstrate a practical example of an electric charging system for an electric public transport system in Gothenburg.

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Power Quality Issues of a Battery Fast Charging Station for a Fully-Electric Public Transport System in Gothenburg City

Urban bus has to start and stop frequently due to typical urban traffic conditions, which, however, can be put to good use by regenerative braking. Regenerative braking is a key technology which not only improves vehicle’s fuel economy in mild braking, but also ensures vehicle safety in emergency braking conditions. Because of the inherent limitations of traditional braking system in recycling energy, it is necessary to change its structure to decouple the brake pressure and the brake pedal force. To solve this problem, a compromise design combining traditional pneumatic braking system with brake-by-wire (BBW) system is adopted in this paper on parallel hybrid electric bus. With the transformed braking system, an efficient coordinated control strategy is proposed to solve the problem caused by the different response speeds of pneumatic braking and regenerative braking. The proposed control strategy is carried out, where the road condition varies and different control methods are adopted. Results show that the adopted braking system and the proposed coordinated control strategy are suitable for different roads, and effective in recovering energy and ensuring vehicle safety. At the same time, shorter braking distance and better control of slip ratio verify the performance of MPC compared with a logical threshold-based control. Therefore, this study may offer a useful theoretical reference to the choice of braking system and braking control strategy design in hybrid electric vehicle (HEV).

Efficient coordinated control of regenerative braking with pneumatic anti-lock braking for hybrid electric vehicle

For an electric vehicle with independently driven axles, an integrated braking control strategy was proposed to coordinate the regenerative braking and the hydraulic braking. The integrated strategy includes three modes, namely the hybrid composite mode, the parallel composite mode and the pure hydraulic mode. For the hybrid composite mode and the parallel composite mode, the coefficients of distributing the braking force between the hydraulic braking and the two motors' regenerative braking were optimised offline, and the response surfaces related to the driving state parameters were established. Meanwhile, the six-sigma method was applied to deal with the uncertainty problems for reliability. Additionally, the pure hydraulic mode is activated to ensure the braking safety and stability when the predictive failure of the response surfaces occurs. Experimental results under given braking conditions showed that the braking requirements could be well met with high braking stability and energy regener...

An integrated control strategy for the composite braking system of an electric vehicle with independently driven axles

A predictive distribution model for a series cooperative braking system of an electric vehicle is proposed, which can solve the real-time problem of the optimum braking force distribution. To get the predictive distribution model, firstly three disciplines of the maximum regenerative energy recovery capability, the maximum generating efficiency and the optimum braking stability are considered, then an off-line process optimization stream is designed, particularly the optimal Latin hypercube design (Opt LHD) method and radial basis function neural network (RBFNN) are utilized. In order to decouple the variables between different disciplines, a concurrent subspace design (CSD) algorithm is suggested. The established predictive distribution model is verified in a dynamic simulation. The off-line optimization results show that the proposed process optimization stream can improve the regenerative energy recovery efficiency, and optimize the braking stability simultaneously. Further simulation tests demonstrate that the predictive distribution model can achieve high prediction accuracy and is very beneficial for the cooperative braking system.

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A Predictive Distribution Model for Cooperative Braking System of an Electric Vehicle

Regenerative braking is an efficient method to achieve better fuel economy and lower emission. The control strategy of regenerative braking for one plug-in hybrid electric city public bus with ABS system is studied. Under Qingdao urban working cycle, the scheme of the regenerative braking system has been developed, the control strategy is given out and simulated. The ideal braking force distribution on front wheel and rear wheel are analyzed. In the control strategy, power is supplied by regenerative braking when lower braking intensity is required and by proportionally combination of regenerative braking and frictional braking deduced by fuzzy-logic control strategy when higher braking intensity is required. And front wheel with rear wheel frictional braking and unchanged motor torque are combined by ideal braking force distribution when braking intensity up to motor’s max torque. And the logistic upper & lower limit value of ABS controller is correspondingly adjusted. The results indicate that, the new control strategy for regenerative braking of plug-in hybrid electric city public bus with ABS system can recover more braking energy with good brake drive ability, and can cooperate with ABS system to guarantee braking safety. And it improves the braking directional stability of the PHEV bus. It also conforms to ECE laws and regulations. Especially under the situation of urban working cycle of Qingdao, the energy consumption can be reduced by 15??20?.

Research on Control Strategy for Regenerative Braking of a Plug-In Hybrid Electric City Public Bus

There are many different factors that influence the safe production of coal mine such as equipment factor, environment factor and artificial factor etc. At current, many coal mines all over the world have built up harmoniously independent mutually monitoring and controlling sub-systems based on variety communicate channels and protocols. In this paper, a monitoring and controlling framework model is built up based on industrial ring Ethernet in coal mine, four layers of network demarcation are put forward, and the method and steps of hardware and software integrates are discussed. At last, the design procedure of a drainage auto control sub-system is introduced according to the Ethernet communication technique.

A monitoring and controlling system based on distributed industrial ring ethernet in coal mine

This paper describes a design for a new type of Remotely Operated Vehicle (ROV) and a system to control it. The ROV and its control system are part and parcel. The control part of the ROV includes the Data Acquisition Program. The Data Acquisition Program is a GUI-based computer program that allows the operator of the ROV to visualize telemetry data from the ROV. It provides near-instantaneous communication with the ROV. The computer-aided design of the prototype is made using Autodesk’s Fusion 360. Then the design was converted to Stereolithography (STL) format and passed through a slicing software called Cura in preparation for 3D printing. An Ender 3D printer was used to manufacture the parts of the design, using Polylactic Acid Thermoplastic Polymer. Computational Fluid Dynamics is conducted to analyze the fluid hydrodynamics (water and pressure flow rates) around the hull of the remotely operated vehicle and the drag force acting on it. Several experimental results have shown the effectiveness of the remotely operated vehicle design.

Wang Liang

Papers

Research on Control Strategy for Regenerative Braking of a Plug-In Hybrid Electric City Public Bus

A monitoring and controlling system based on distributed industrial ring ethernet in coal mine

Design and development of a remotely operated vehicle and its control system