Showing papers on "Dynamic braking published in 2010"

Studies of regenerative braking in electric vehicle

Abstract: Generally the braking system for a car is based on hydraulic braking technology. However, this traditional braking methodology causes a lot of energy wastage since it produces unwanted heat during braking. Thus, the invention of regenerative braking in electric car has overcome these disadvantages moreover it helps in save energy and provides higher efficiency for a car. In regenerative mode, the motor act as a generator, it transfers the kinetic to electrical energy to restore the batteries or capacitors. Meanwhile, the brake controller monitors the speed of the wheels and calculates the torque required plus the excessive energy from the rotational force that can be converted into electricity and fed back into the batteries during regenerative mode. The merits of regenerative braking over traditional braking are energy conservation, wear reduction, fuel consumption and more efficient in braking. Nowadays, the brilliant technology in automotive industry towards regenerative braking is improving. By using a flywheel and ultracapacitor with DC-DC converter it had enhance the regenerative performance. In this paper, the working principle and braking controller for the regenerative braking have been studied to promote the efficiency and realization of energy saving in the electric vehicle.

Efficient Recovery of Braking Energy through a Reversible DC Substation

Abstract: The full regeneration of the braking energy is one of the most promising sources of energy savings to transport system operators. This paper presents the outcome of a RailEnergy cooperative research program focusing on reduction of energy consumption in transport systems. Today, urban transportation systems are generally fed at 750 Vdc or 1,500Vdc via rectifier bridges and trains are equipped with modern 3-phase ac traction packages. This allow for easier and more effective implementation of dynamic braking over a wider range of speed and voltage with the possibility of feeding back some of the energy via the 3rd rail or OCS to adjacent trains. The target of this project is to improve the line receptivity of dc power systems by transferring the excess energy to the ac side and thus regenerate it, via the transformer, to the ac medium voltage distribution network that is naturally receptive. This concept transforms the traditional unidirectional dc traction into a reversible one. It is suitable to all known types of dc traction power supply systems from 600Vdc up to 3,000Vdc. The key benefits expected from reversible dc traction substations are: • Regeneration of 99% of the braking energy at all time, while maintaining priority to natural exchange of energy between trains; this will allow eliminating the braking resistors, and thus reduce the train mass and heat release; • Regulation of its output voltage in traction and regeneration modes to reduce losses, and increase the pick-up of energy from distant trains, and • Reducing the level of harmonics and improvement of the power factor on the ac side. Under an Alstom funded internal R&D programme two 750 Vdc prototypes dc reversible substations were built and tested on a dedicated tramway test-track at the Alstom plant in La Rochelle France. To reduce development time & costs the prototypes were built using state-of-the-art industrial variable speed drive converters, active harmonic filters, high power semiconductors modules, modern controls and protections, modularity, high integration while taking into account the specific requirements of the railway industry. The test results confirmed the theoretical findings and demonstrated that the reversible substations allowed regenerating all of the excess available kinetic energy of the tramway.

Regenerative brake system reset feature and adaptive calibration for hybrid and electric vehicles

Abstract: In a vehicle equipped for regenerative and non-regenerative braking, regenerative braking only is applied to predetermined wheels in response to braking demand when the driver attempts to slow the vehicle at a first rate (

Integrated control of braking energy regeneration and pneumatic anti-lock braking

Abstract: This paper mainly focuses on integrated control of the brake system of a hybrid electric vehicle, i.e. the integration of friction braking and regenerative braking during anti-lock braking control and series brake blending during normal deceleration. Based on a series regenerative braking system, the structure of an integrated brake system is proposed. The models of each part of a hybrid electric bus are built in MATLABAE Simulink, taking authorized articles as references. A test bench with the original pneumatic brake system of a bus is also built to carry out hardware-in-the-loop (HIL) tests of the integrated brake system and to study the characteristics of the system better. The integrated control strategy is proposed on the basis of a pneumatic anti-lock braking strategy. Simulation results show that the participation of regenerative braking in the anti-lock braking control can be beneficial to both the ride comfort and the braking performance of the vehicle. HIL test results validate the resul...

Dynamic braking for current source converter based drive

Abstract: Current source converter (CSC) based motor drives and control techniques are presented in which DC link current is regulated to a level set by the output inverter during dynamic braking operation by pulse width modulation of a braking resistance connection signal to maintain control of motor torque and speed while mitigating or preventing line side regenerative currents.

Regenerative braking torque compensation device, methods for regenerative braking torque compensation and a hybrid vehicle embodying such devices and methods

Abstract: The present invention compensates a regenerative braking amount by applying a target shift step and a shift phase in a case that the vehicle is in deceleration according to a brake demand and regenerative braking is performed. A regenerative braking torque compensation method of a hybrid vehicle may include a step of determining a regenerative braking operation amount to control regenerative braking torque while regenerative braking is needed, a step of applying a real shift ratio to determine a regenerative braking operation amount if shifting is detected during the regenerative braking, a step of applying a target shift step and a shift phase according to the shifting to decide a regenerative braking compensation amount, and a step of applying the regenerative braking operation amount to the regenerative braking compensation amount to control final regenerative braking torque.

Regenerative braking for electric vehicle based on fuzzy logic control strategy

Abstract: In order to recycle more energy in the process of regenerative braking, we design a regenerative braking force calculation controller based on fuzzy logic. The sugeno's interface fuzzy logic controller has three-inputs including the driver's brake requirements, vehicle speed and batteries' SOC and one-output which is the regenerative braking force. To ensure charging safety, the influence of batteries' temperature is also taken into consideration. Besides, we modify the original braking force distribution regulations in the simulation software--ADVISOR. The simulation results verify that the method can not only recycle more energy from braking but also ensure the safety of braking and the batteries.

Hybrid locomotive regenerative energy storage system and method

Abstract: An energy storage car for a locomotive includes a hydraulic energy storage system designed to capture and reuse energy normally lost in dynamic braking The energy storage car is preferably configured to provide functions sufficient to replace one of multiple locomotives used to pull a freight train. Braking and other methods for improved efficiency of such trains are provided.

Rail vehicle system

Abstract: A rail vehicle system includes a locomotive and a plurality of load units (freight cars) attached to the locomotive for movement along a railroad track. The load units may be tanker cars, box cars, and/or flatbed cars. Each load unit includes a traction motor (connected to one or more wheels of the load unit), an electrical energy storage system onboard the load unit for providing electrical power to the load unit traction motor; and a load unit engine onboard the load unit that provides charging electric energy to the electrical energy storage system. (Alternatively or in addition, the electrical energy storage system may be charged through dynamic braking.) In a train formed of only the locomotive(s) and load units, all rail vehicles of the train, even freight cars, provide tractive effort.

Braking force control apparatus for vehicle

Abstract: An electronic control unit of a braking force control apparatus for a vehicle activates, as a first state, in-wheel motors in a regeneration state, thereby generating motor braking torques, and causes friction brake mechanisms to generate friction braking forces. Moreover, the unit activates, as a second state, the motors in a power running state, thereby generating motor driving torques, and causes the mechanisms to generate friction braking forces. Then, when the state is caused to transition between the first state and the second state, the unit changes magnitudes of the braking torques or the driving torques generated by the motors to one of increase and decrease, and changes magnitudes of the friction braking forces generated by the mechanisms to one of increase and decrease.

Sliding mode control of anti-lock braking system: an overview

Abstract: An anti-lock braking system control is a rather difficult problem due to its strongly nonlinear and uncertain characteristics. To overcome these difficulties, robust control methods should be employed such as a sliding mode control. The aim of this paper is to give a short overview of sliding mode control techniques implemented in the control of ABS. The most used control algorithms are applied to a quarter vehicle model to demonstrate the advantages of this control approach. Fast convergence and good performances of the designed controllers are verified through digital simulations and validated in real time applications using a laboratory experimental setup.

Braking control apparatus for electric vehicle

Abstract: In a braking control apparatus for an electric vehicle, a target braking torque command value calculation section calculates a target braking torque command value on a basis of at least one of a state of road wheels and a braking request by a vehicle driver, a frequency component decomposition section decomposes a target braking torque command value into a first frequency component lower than a resonance frequency of a drive train and a second frequency component equal to or higher than the first frequency component, and a braking force control section provides an electrical braking torque for road wheels on a basis of a motor torque command value corresponding to the first frequency component and provides a frictional braking torque for the road wheels on a basis of a frictional braking torque command value corresponding to the second frequency component.

Braking apparatus, electric drive, and elevator system

Abstract: The invention relates to a braking apparatus, an electric drive and an elevator system. The braking apparatus (1 ) comprises an apparatus (3) for dynamic braking, for braking an electric machine (4) with dynamic braking, an input for the control signal (5, 7) of the braking apparatus, and also a controller (8), for controlling the apparatus (3) for dynamic braking as a response to the aforementioned control signal (5, 7) of the braking apparatus.

Regenerative braking control in vehicles

Abstract: Methods and systems for modulating regenerative braking in a vehicle having a regenerative braking system and an energy storage system are provided. A value is obtained for a variable pertaining to a condition that affects energy absorption of the energy storage system. A regenerative braking torque capacity for the regenerative braking system is determined using the value. Regenerative braking is controlled via the regenerative braking system based at least in part on the regenerative braking torque capacity.

Influence of tyre transience on anti-lock braking

Abstract: Transient tyre characteristics can have significant influence in vehicle handling, particularly in anti-lock braking system (ABS), which involves wheel speed oscillations as a result of rapid changes in wheel brake pressure. Hitherto, ABS studies have been conducted mostly with straight-line motion. Relatively simple vehicle models have been used which cannot capture the interactions between non-linear handling dynamics and tyre behaviour. This article takes such interactions into account, using a non-linear 14-degrees-of-freedom vehicle model in combination with three different single-point contact tyre models with transient characteristics. They include a stretched-string-based model, a modified stretched-string model, and a contact mass model. The particularly demanding situation of combined cornering/ABS braking is investigated. It is shown that although all tyre models are of similar bandwidth (maximum frequency ≈ 15 Hz), the simple string tyre model fails to cope with the non-linearities involved in combined braking/cornering and predicts greater braking distances than the two more enhanced tyre models.

Power semiconductor module

Abstract: PROBLEM TO BE SOLVED: To provide a power conversion device having a dynamic braking function, which improves shut-down performance of an AC generator and achieves miniaturization and cost reduction. SOLUTION: A switching element for dynamic braking is provided inside a power semiconductor module. By turning the switching element on, each phase terminal of an AC generator is short-circuited via the switching element, a braking current is passed to the AC generator, and the AC generator is shut down immediately. COPYRIGHT: (C)2010,JPO&INPIT

Dynamic regenerative braking torque control

Abstract: Methods, systems, and program products for adjusting regenerative braking torque in a vehicle having wheels and a regenerative braking system providing the regenerative braking torque are provided. A deceleration of the vehicle is determined. A wheel slip of the wheels is determined. The regenerative braking torque is adjusted for the regenerative braking system using the deceleration and the wheel slip.

Regenerative braking torque estimation and control approaches for a hybrid electric truck

Abstract: Regenerative braking torque control problem is an important issue in a hybrid electric vehicle braking system. The braking performance has various influences on the vehicle driving performances such as fuel economy, braking efficiency and drivability. In this paper, a regenerative braking torque estimation approach is proposed which requires the wheel speed measurement only. Based on the estimated regenerative braking torque, a feedback braking torque control scheme is provided to achieve satisfactory control effect in a hybrid electric truck. Finally, simulation results are demonstrated to validate the proposed estimation and control approaches.

Braking control method for electric vehicle

Abstract: The present invention features braking control methods for an electric vehicle. Such methods include identifying a vehicle operational condition occurring during regenerative braking that reduces regenerative braking capacity; linearly reducing the amount of regenerative braking of a motor of the electric vehicle after identifying such a vehicle operational condition; and at the same time, increasing the amount of hydraulic braking of a hydraulic braking system to compensate for the reducing of the amount of regenerative braking. Such operational conditions include when the temperature of a motor or battery is increased above a predetermined level during regenerative braking or when the shift lever is shifted to Neutral (N) position by a driver during regenerative braking.

Improvement of drivability and fuel economy with a hybrid antiskid braking system in hybrid electric vehicles

Abstract: When braking on wet roads, Antilock Braking System (ABS) control can be triggered because the available brake torque is not sufficient. When the ABS system is active, for a hybrid electric vehicle, the regenerative brake is switched off to safeguard the normal ABS function. When the ABS control is terminated, it would be favorable to reactivate the regenerative brake. However, recurring cycles from ABS to motor regenerative braking could occur. This condition is felt to be unpleasant by the driver and has adverse effects on driving stability. In this paper, a novel hybrid antiskid braking system using fuzzy logic is proposed for a hybrid electric vehicle that has a regenerative braking system operatively connected to an electric traction motor and a separate hydraulic braking system. This control strategy and the method for coordination between regenerative and hydraulic braking are developed. The motor regenerative braking controller is designed. Control of regenerative and hydraulic braking force distribution is investigated. The simulation and experimental results show that vehicle braking performance and fuel economy can be improved and the proposed control strategy and method are effective and robust.

Method for controlling torque at one or more wheels of a vehicle

Abstract: An exemplary method for controlling torque at one or more wheels of a vehicle, including controlling both positive torque (acceleration) and negative torque (braking) with a single torque command. According to one embodiment, the method interprets the acceleration and braking intent of the driver, takes into consideration certain special conditions (e.g., vehicle dynamic conditions like wheel slip, over- and under-steer, etc.), and generates one or more individual torque commands that are sent to individual wheels or corners of the vehicle. The individual torque commands may address certain chassis and powertrain functions like acceleration and braking, and may provide full-feature torque control (i.e., acceleration, braking, vehicle dynamics, etc.) on an individual wheel basis. It is also possible for the method to be used in a system where a number of the common chassis, powertrain and/or vehicle dynamic modules have been integrated into a single torque control module or the like.

Method and braking system for influencing driving dynamics by means of braking and driving operations

Abstract: A method and a braking system are provided, in which the driving dynamics of a motor vehicle are influenced, a driver-independent braking action generating a yawing moment which assists a steering in or steering round of the motor vehicle, and a driver-independent increase in the drive torque being caused on at least one wheel, in order at least partially to compensate the braking deceleration of the motor vehicle, a braking action being required when the ratio of the instantaneously used coefficient of friction and of the possible utilizable coefficient of friction overshoots a stipulated threshold value.

Braking force control device for vehicle

Abstract: A braking force control apparatus for a vehicle estimates the friction coefficient µ of a road surface as the state of the road surface on which the vehicle travels, and determines (computes) an ideal braking force µW (target braking force) by making use of the estimated road surface friction coefficient µ. When the estimated road surface friction coefficient µ is equal to or greater than a predetermined friction coefficient µ0, the braking force control apparatus operates an in-wheel motor (electrical force generation mechanism) in a regeneration state to thereby generate a motor braking torque Tmr, and causes a friction brake mechanism (braking force generation mechanism) to generate a frictional braking force Bf computed by subtracting the motor braking torque Tmr from the ideal braking force µW. Meanwhile, when the estimated road surface friction coefficient µ is less than the predetermined friction coefficient µ0, the braking force control apparatus operates the in-wheel motor (electrical force generation mechanism) in a power running state to thereby generate a motor driving torque Tmc, and causes the friction brake mechanism (braking force generation mechanism) to generate a frictional braking force Bf computed by adding the motor driving torque Tmc to the ideal braking force µW.

Braking Force Distribution Strategy for HEV Based on Braking Strength

Abstract: The possibility of recovering vehicle kinetic energy is one inherent advantage of hybrid electric vehicle (HEV). Due to the introduction of electric regenerative braking, the structure, design and control of a hybrid electric vehicle is quite different from the pure mechanical braking of conventional vehicles. In this paper, the decelerations of the vehicle in typical urban driving cycles and the influences of regenerative braking have been investigated. The results provide strong supports to the design of the braking force distribution strategy for the hybrid electric vehicle. This paper designs a deceleration sensitive braking force distribution strategy to distribute the desired total braking force to the front and rear axles. This strategy can recovery more braking energy and can keep the vehicle more stable while the vehicle is braked. The proposed distribution strategy is tested through the simulation, and the simulation results show the distribution strategy is effective.

Model and Simulation of a Super-capacitor Braking Energy Recovery System for Urban Railway Vehicles

Abstract: In this paper, a braking energy recovery system based on super-capacitor was presented. The method use super-capacitor and the conventional braking resistance constitute a new braking unit to realize the regenerative energy recovery, when braking, braking energy will be stored in the super-capacitor by a DC/DC converter. meanwhile, the conventional braking resistance still keep in system to ensure the security. In order to validate the design and do further research, the paper established the mathematical model and simulation model of the whole system, which include power supply unit, traction motor unit, driven control unit, super-capacitor unit etc. the traction motor is AC motor, the motor parameters are set according to the experimental platform and the motor control method is designed as rotor flux oriented vector control. At the end, the simulation is done, the results of simulation is consistent with the experimental results of the test bench, which means the model built in this paper is correct and useable. Based on the mathematical model and simulation model, the further research such as energy efficiency analysis and advanced control method study can be done.

Effect on regenerative braking efficiency with deceleration demand and terrain condition

Abstract: Deceleration rate and terrain adhesive coefficient are critical factors, which are drastically diminishing the regenerative energy enhancement in the hybrid electric vehicle. In addition to that, sizing the electric propulsion system also very important to increase the acceleration performance and regenerative braking efficiency. For example, oversizing the electric propulsion system will occupy additional space and increase the weight of the vehicle. On the other hand , down sizing the electric propulsion system will not contribute to achieve the fuel economy of the vehicle, where the effect of the hybridization is negligible. Nevertheless, even for a given hybrid drive train design, the electric propulsion system cannot produce all kind of braking power to stop the vehicle within the expected braking condition. Therefore the involvement of the mechanical braking system is inevitable to ensure the safety braking. This paper addresses the correlation between the regenerative energy, terrain adhesive coefficient and deceleration rate of the vehicle. Here, front wheel drive vehicle is considered for the simulation and a decision making strategy is designed to split and distribute the braking force to front and rear wheels accordingly. Finally a simulation study is conducted to outline the proposed analysis. (6 pages)

Mobile diesel power system with separated engine and exhaust

Abstract: According to the present disclosure, a train comprising one or more locomotives coupled to one or more tenders, which contain at least one of an exhaust after-treatment or a waste heat recovery system and optionally one or more other locomotive subsystems, such as dynamic braking, energy storage, driven wheels, and fuel storage, is provided. Accordingly, the present disclosure may have one or more of the following advantages: a tender to house an exhaust after-treatment system thereby easing space constraints on the locomotive power traction car. Additionally, said tender may include a large fuel tank, waste heat recovery system, and energy storage, thereby providing the means to substantially decrease fuel consumption or increase power, both with the option of switching to a different fuel source.

Thermal management system, vehicle, and associated method

Abstract: A system includes a cooling system having a cooling fluid for cooling an engine and a radiator fan motor; a dynamic braking system configured to supply electrical energy to the fan motor during a braking event; and a controller that is operable to direct the electrical energy from the dynamic braking system to the fan motor to cool the coolant to a predetermined minimum threshold temperature. A method includes switching a vehicle thermal management system from a first mode of operation in which the coolant is maintained at a steady operating temperature to a second mode of operation in which the coolant is cooled to a minimum threshold temperature.

Master braking system and method therefor

Abstract: A master braking system provides enhanced braking capabilities to various types of vehicles. The master braking system may utilize one or more braking pads that enlarge the contact surface between a vehicle and the road surface as compared to the vehicles tires. The master braking system may comprise an actuator powered by a power source and controlled by a control module. When deployed, a braking pad contacts the road surface to quickly slow or stop a vehicle. The braking pad may then be retracted to allow the vehicle to move freely once again.