Showing papers on "Dynamic braking published in 2007"

Fault Ride-Through of Large Wind Farms Using Series Dynamic Braking Resistors (March 2007)

Abstract: Fault ride-through (FRT) is required for large wind farms in most power systems. Fixed speed wind turbines (FSWTs) are a diminishing but significant sector in the fast-growing wind turbine (WT) market. State-of-art techniques applied to meet grid requirements for FSWT wind farms are blade pitching and dynamic reactive power compensation (RPC). Blade pitching is constrained by the onerous mechanical loads imposed on a wind turbine during rapid power restoration. Dynamic RPC is constrained by its high capital cost. These present technologies can therefore be limiting, especially when connecting to smaller power systems. A novel alternative technology is proposed that inserts series resistance into the generation circuit. The series dynamic braking resistor (SDBR) dissipates active power and boosts generator voltage, potentially displacing the need for pitch control and dynamic RPC. This paper uses a representative wind farm model to study the beneficial effect of SDBR compared to dynamic RPC. This is achieved by quasi-steady-state characterization and transient FRT stability simulations. The analysis shows that SDBR can substantially improve the FRT performance of a FSWT wind farm. It also shows that a small resistance, inserted for less than one

Hybrid energy off highway vehicle propulsion circuit

Abstract: A system and method for retrofitting a propulsion circuit of an existing Off Highway Vehicle to enable the propulsion circuit to operate as a hybrid energy Off Highway Vehicle propulsion circuit. The hybrid propulsion circuit includes a primary power source, and a traction motor for propelling an Off Highway Vehicle in response to the primary electric power. The traction motor has a motoring mode of operation and a power dissipation mode of operation. The traction motor generates dynamic braking electrical power in the power dissipation mode of operation. An electrical energy storage system includes a chopper circuit coupled to an energy storage device. The storage device is responsive to the chopper circuit to selectively store electrical energy generated in the power dissipation mode. The storage system selectively provides secondary electric power from the storage device to traction motor to assist in propelling the Off Highway Vehicle during the motoring mode.

Design and Control Principles of Hybrid Braking System for EV, HEV and FCV

Abstract: Due to the introduction of electrical regenerative braking, the structure, design and control of braking system of an electric vehicle (EV), hybrid electrical vehicle (HEV) and fuel cell vehicle (FCV) is quite different from the pure mechanical braking system of conventional vehicles. Desirable braking performance not only guarantee to quickly stop the vehicle and maintain the traveling direction stable and controllable, but recapture the braking energy as much as possible on various conditions of road. In this paper, the braking energy characteristics on vehicle speed and braking power in typical urban driving cycles have been investigated. The results provide strong supports to the design and control of such hybrid braking system. Two hybrid braking systems have been introduced. One is parallel hybrid braking system, which has a simple structure and control. The other is fully controllable hybrid braking system. Two typical control strategies for this system have been established. One emphasizes optimal braking performance and the other on optimal braking energy recovery.

Nonlinear control design of anti-lock braking systems with assistance of active suspension

Abstract: With the utilisation of backstepping control design schemes, a nonlinear anti-lock braking system (ABS) is applied to a quarter-car model, assisted by active suspension. An ABS must be able to release the wheel-locking situation while assisting the vehicle to stop in the shortest possible distance. Although the braking distance can be reduced by the control torque from disk/drum brakes, the braking time and distance could be further improved if the normal force generated from active suspension systems is considered simultaneously. As a result, the integration of the ABS and the active suspension system would indeed enable further enhancement of the system performance resulting in a reduction of braking time and stopping distance. Some comparative simulations are given to illustrate the excellent performance of the proposed integrated ABS.

Method and apparatus for braking and stopping vehicles having an electric drive

Abstract: A method and apparatus are provided for braking and stopping a vehicle whose powertrain includes an electric drive. The electric drive is used to generate braking torque which is used to decelerate the vehicle down to a full stop. The braking torque is achieved using any of several closed loop speed control systems. The system can be used as a substitute for or as a supplement to conventional friction bakes.

Apparatus and method for controlling braking-force distribution in vehicle collision

Abstract: An apparatus and method for controlling a braking-force distribution in a vehicle collision is used in a vehicle including at least one electric storage device and at least one motor-generator for driving and braking. When the vehicle decelerates or stops in response to a brake operation, regenerative cooperative brake control is performed in which a braking force of a frictional brake is reduced or eliminated while a braking force of a regenerative brake applied by the motor-generator is increased by an amount corresponding to the reduction in the braking force of the friction brake. When the vehicle collides, the apparatus reduces the braking force of the regenerative brake applied by the motor-generator and increases the braking force of the friction brake.

Braking apparatus for vehicle

Abstract: A braking apparatus for a vehicle includes a hydraulic brake apparatus generating a basic hydraulic pressure so that a basic hydraulic braking force is generated at wheels, the hydraulic brake apparatus generating a controlled hydraulic pressure so that a controlled hydraulic braking force is generated at the wheels, a regenerative brake apparatus causing a regenerative braking force to be generated at any of the wheels, and braking force replacement controlling means for gradually replacing the regenerative braking force with the controlled hydraulic braking force while braking during which at least the regenerative braking force is applied for a purpose of achieving a braking force replacement control to ensure a total braking force required for the wheels by decreasing the regenerative braking force at a gradient within a predetermined range and by increasing the controlled hydraulic braking force in response to the decrease of the regenerative braking force.

Optimal Brake Torque Distribution for a Four-Wheeldrive Hybrid Electric Vehicle Stability Enhancement

Abstract: Vehicle stability control logic for a four-wheel-drive hybrid electric vehicle is proposed using the regenerative braking of the rear motor and an electrohydraulic brake (EHB). To obtain the optimal brake torque distribution between the regenerative braking and the EHB torque, a genetic algorithm is used. The genetic algorithm calculates the optimal regenerative braking torque and the optimal EHB torque for the given inputs of the desired yaw moment and road friction coefficient. Based on the optimal brake torque distribution, the vehicle stability control logic proposed generates the desired direct yaw moment to compensate the errors of the side-slip angle and yaw rate by a fuzzy control algorithm corresponding to the driver's steering angle and vehicle velocity. Performance of the vehicle stability control logic is evaluated by comparison of the fixed regenerative braking and the optimal regenerative braking for a single lane change manoeuvre. It is found from the simulation results that the opt...

Methods and systems to control braking of a trailer hitched to a vehicle

Abstract: A method for controlling braking of a trailer hitched to a vehicle with a braking control system during a braking event includes the steps of determining vehicle speed, measuring an amount of braking intent applied to the braking control system, determining a first level of braking output, providing the first level of braking output to the trailer if the vehicle speed is greater than a first predetermined threshold, and providing a second level of braking output to the trailer if the vehicle speed is less than the first predetermined threshold and the amount of braking intent has not exceeded a second predetermined threshold during the braking event. The first level of braking output corresponds to a function of the amount of braking intent. The second level of braking output is less than the first level of braking output.

An Introduction to Regenerative Braking of Electric Vehicles as Anti-Lock Braking System

Abstract: Anti-lock braking systems (ABS) are well known in the automotive industry as one of the most critical active safety systems. ABS improves vehicle safety by reducing longitudinal breaking distance. This occurs by the control of the wheel slip. In this study, a basic modeling approach has been introduced on a quarter car model by using ANSOFT Simplorer for the following braking modes: hydraulic braking and all electric vehicle regenerative braking concept.

Impact of regenerative braking on vehicle stability

Abstract: In a series regenerative braking system, regenerative braking is generally used to the maximum extent prior to the introduction of friction braking During the regenerative braking phase, this generally means that the front to rear braking distribution will be less than ideal since it is often only possible to apply braking torque to a single axle This can have significant implications for vehicle handling and stability during cornering, particularly if the axle concerned is the rear axle The first part of this paper considers the impact on vehicle stability of applying regenerative braking through the rear axle of a sports utility vehicle It is shown that, on low μ surfaces in particular, a moderately sized electric motor has the capability to significantly compromise vehicle stability during cornering The second part of the paper then considers how this issue may be resolved Various solutions are considered and it is shown that redistributing the regenerative braking torque using active driveline devices allows vehicle stability to be protected whilst maintaining maximum energy recovery

Vehicle, control method thereof and braking device

Abstract: During braking, lower limits Tm2min and Tm3min are set based on an input limit Win of a battery and a brake pedal position BP (S190), and the set lower limits Tm2min and Tm3min limit regenerative torques output from motors MG2 and MG3 (S220). This prevents an output of an excessive braking force and torque shock caused by a hydraulic brake being not able to follow sudden changes in the regenerative torques output from the motors MG2 and MG3 when the vehicle speed is reduced.

Electric powered vehicle performing regenerative braking

Abstract: A regeneration control portion sets a torque command value (in general, a negative value) of a motor generator at a time of regenerative braking. A braking cooperative control portion calculates a total braking force (power) required for the entire vehicle based on a brake depression force BK of a driver and also controls the shares of the output of the total braking force between a hydraulic brake and the motor generator. An MG-ECU drives and controls the motor generator so that a regenerative torque is generated according to a torque command value. The regeneration control portion puts a limitation such that the absolute value of the regenerative torque is smaller at a time of downhill travel than at a time of flat-road travel, for the same brake operation.

Braking control system and braking control method

Abstract: A braking control system (1) includes: an ECU (20) that determines the likelihood of collision with an object based on detection results by a millimeter wave radar (10), a stereo camera (11) and the like; a brake actuator (30) that automatically applies a braking force based on the determination results; a steering angle sensor (14) that detects the steering condition by a driver; and so forth. When it is determined that a collision with an object is likely and automatic braking is started, and it is subsequently determined that a collision with the object is avoided through a steering operation by the driver, the ECU (20) sets a smaller gradient with which the target deceleration (target braking force) in the automatic braking is reduced in comparison to when a collision with the object is avoided not through the steering operation by the driver.

Electric powertrain system having bidirectional DC generator

Abstract: An electric powertrain for use with an engine and a traction device is disclosed The electric powertrain has a DC motor/generator operable to receive at least a portion of a first mechanical output from the engine and produce a DC power output The DC motor/generator is also operable to receive DC power and produce a second mechanical output The electric powertrain further has a drivetrain operable to receive the DC power output and use the DC power output to drive the traction device The drivetrain is also operable to generate DC power when the traction device is operated in a dynamic braking mode

Antilock braking systems and methods

Abstract: Improved anti-lock brake systems (ABS) employed on aircraft and land vehicles and methods of operating same employing a sliding mode observer (SMO) incorporated into an ABS algorithm requiring only measurement of wheel speed to regulate the application of braking torque are disclosed. Braking is optimized simply by maintaining an SMO estimate of differential wheel torque (road/tire torque minus applied brake torque) derived from wheel speed at an extremum via applying or releasing the brakes as the extremum is passed through.

Braking method for hybrid vehicles compensating for an electric braking torque

Abstract: The invention relates to a braking method for a hybrid vehicle (1) comprising a drivetrain (3) controlled by a drivetrain computer (12), and a hydraulic braking system (15) controlled by a braking computer (21). In this method, as soon as the drivetrain computer (12) detects that the electrical braking torque is decreasing, this drivetrain computer (12) informs the hydraulic braking computer (21) of the value of the reduction in electric braking torque. The braking computer (21) then operates the hydraulic braking system (15) in such a way that the hydraulic braking torque applied to the wheels (2) by the brakes (17) compensates for this reduction in electric braking torque.

Elevator brake with magneto-rheological fluid

Abstract: An elevator brake assembly includes a braking fluid for providing a braking force. A first magnet provides a first magnetic field that influences the braking fluid to provide the braking force. The second magnet selectively provides a second magnetic field that controls how the first magnetic field influences the braking fluid to control the braking force.

System and method for providing head end power for use in passenger train sets

Abstract: A head end power system carried on a locomotive for a passenger train set that captures and stores excess electrical energy generated during dynamic braking of the locomotive. This excess electrical energy is converted to head end power for use on attached passenger railcars. Because passenger trains activate dynamic braking frequently, sufficient dynamic braking energy can be captured to supply a substantially continuous demand for head end power. In the event that the amount of captured energy is insufficient to meet demand, the head end power system may supplement the captured energy with energy generated by the primary power source on the locomotive.

Regenerative braking with hill descent control

Abstract: An automotive hill descent control includes a friction-braking subsystem and a non-friction braking subsystem with engine-based braking and regenerative braking. The regenerative and engine-based braking systems may be controlled according to the position of a manual switch, as well as inversely proportionally to the slope upon which a vehicle is being operated, and according to the speed of the vehicle.

Regenerative energy storage system for hybrid locomotive

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 methods, and methods to capture and reuse dynamic braking energy on long grades, for such trains are provided.

Electric parking brake control system

Abstract: An electric parking brake control apparatus for controlling an electric actuator for driving a parking brake is provided with: an inclination determination unit for determining an inclination of a road surface based on at least a change of a vehicle speed; and a braking force setting unit. The braking force setting unit sets a braking force of the parking brake to a slope braking force which is larger than a flat ground braking force set when the vehicle is stopped on a flat ground, according to an inclination of the road surface which is determined by the inclination determination unit. Moreover, in the event that the vehicle is stopped again without experiencing a running over a predetermined vehicle speed after braking with the slope braking force has been cancelled, the braking force setting unit sets the braking force to the slop braking force.

Brake force control device and method

Abstract: A braking force control device includes: a brake control device (brake controller 24) that controls a mechanical brake braking torque by operating electric actuators 23FL, 23FR 23RL, 23RR so as to achieve a requested brake braking torque; a motor control device (motor controller 42) that controls a motor torque by operating motors 41FL, 41FR, 41RL, 41RR so as to achieve the requested motor torque; a requested braking torque calculation device 51 a that calculates; the requested braking torques of wheels 10FL, 10FR, 10RL, 10RR; a battery requested electric power calculation device 51c that finds a battery requested electric power based on the target amounts of electricity charged in batteries 31, 32, 34; and an individual braking torque calculation device 51b that finds the requested motor torque and the requested brake braking torque that cause the requested braking torque to be generated based on the battery requested electric power and the requested braking torque.

A system and a method for controlling braking of a motor vehicle during downhill driving

Abstract: A system for controlling braking of a motor vehicle during downhill driving, in which the vehicle is provided with a service frictional braking device (18) and an auxiliary braking device (25), comprising a retarder brake (26) and a lever (40) for activating the retarder brake by the driver of the vehicle, comprises means (29) adapted to, upon activation of said retarder brake (26) by actuating said lever (40) by the driver for applying a braking action to the vehicle when driving downhill, based upon values of parameters of the driving conditions of the vehicle, calculate whether the auxiliary braking device is able to alone obtain said braking action to be applied to the vehicle. The braking control means (28) is adapted to activate the service frictional braking device to assist said auxiliary braking device when said calculation states that the auxiliary braking device is not able to alone obtain said braking action to be applied to the vehicle. (Fig 1).

Dynamic braking circuit for a hybrid locomotive

Abstract: The present invention relates generally to methods of dynamic braking. Two embodiments include braking circuits for vehicles such as, for example, locomotives which are operable down to very low speeds. These circuits can provide a braking force even at zero locomotive speed.

Braking system for an aircraft and a method of monitoring braking for an aircraft

Abstract: A braking system (1) for an aircraft which includes a by-pass control system (9) for activation when undemanded braking or loss of braking is detected The braking system (1) comprises: a brake pedal transducer (2) for generating a brake pedal actuation signal when a brake pedal (3) is applied; brake actuation means (5) for activating a brake (6) on receipt of a braking signal; braking pressure transducer means (7) for generating a braking output signal related to the braking force applied to the brake (6); primary processing means (4) in electrical communication with the brake pedal transducer (2) and the brake actuation means (5) and adapted to generate a braking signal on receipt of a brake pedal actuation signal; secondary processing means (8) adapted to receive the brake pedal actuation signal and braking output signal; and a bypass braking control system (9) adapted to receive the brake pedal actuation signal from the brake pedal transducer (2) and generate a braking signal in response to the brake pedal actuation signal The secondary processing means (8) is adapted to disable the primary processing means (4) and enable the bypass braking control system (9) on detection of undemanded braking or loss of braking from the brake pedal actuation signal and braking output signal

Method of distributing braking between the brakes of an aircraft

Abstract: A method of distribution braking between the brakes of an aircraft. The method includes a first step of estimating a braking force objective and a steering torque objective to be achieved by the brakes of the aircraft. It also includes the steps of defining at least two groups of brakes (12, 13) and determining, for each group, a braking level that is to be achieved by the group. The braking levels being calculated in such a manner that braking performed in application of the braking levels is, at least under normal operating conditions of the brakes, in compliance with a braking force objective and with a steering torque objective.

Driving/braking control device for vehicle for controlling brake holding and start of vehicle

Abstract: PROBLEM TO BE SOLVED: To provide the driving/braking control device of a vehicle for quickly starting a vehicle so that any impact or noise can be suppressed when it starts while achieving the improvement of fuel economy and the suppression of exhaust gas after executing brake hold control and creep cut control SOLUTION: This driving/braking control device of a vehicle is provided with a braking force holding control means for holding the braking force of a wheel even after a braking operation by a driver is released; a driving torque control means for reducing driving torque to be transmitted to the wheel during the execution of the holding control of the braking force of the wheel; and a start prediction detection means for detecting whether or not the start of the vehicle is predicted The driving torque control means increases torque that has been reduced until the release of the holding of the braking force is executed according as the prediction of the start of the vehicle is detected by the start prediction detection means COPYRIGHT: (C)2009,JPO&INPIT

Vehicle braking apparatus

Abstract: A vehicle braking apparatus is provided with a brake operating element that is operated by a driver, and an actuator that generates a braking force in accordance with a braking operation of the brake operating element. A controller is operatively arranged to control the actuator such that an increase in a rate of change of the braking force with respect to the braking operation by the driver is suppressed upon determining that vehicle cabin background noise is equal to or below a prescribed threshold value.

Detecting device of elevator dynamic brake force moment

Abstract: An elevator dynamic braking toque detection device consists of an electronic pulse counting controlling unit, a rotary pulse coder and a coupling, which is connected with relevant parts of the detected elevator equipments via a conductor and the coupling. The electronic pulse counting controlling unit is positioned inside a special instrument box, the input interface of the electronic pulse counting controlling unit is connected with the rotary pulse coder via the conductor and the output interface is connected with the electric-control system of the detected elevator; the rotary pulse coder is mechanically connected with the rotary shaft side of the elevator tractor via the coupling, the coupling is suitable for the rotary shaft diameter, installation parts and connection way of any elevator tractor. The detection device is able to display the detected pulse value through the digital monitor, is able to detect the dynamic braking distance of any type tractor-type elevator and could display a precise detection value to provide correct foundation for the judgment of the elevator braking torque.