Topic
Dynamic braking
About: Dynamic braking is a research topic. Over the lifetime, 3472 publications have been published within this topic receiving 34897 citations. The topic is also known as: Rheostatic brake.
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Patent•
27 Apr 1978TL;DR: In this article, a stopping or braking arrangement is provided for an automatic flue damper assembly of the type in which the motor of a clockwork mechanism is energized to hold the damper closed and the mechanism is mechanically biased to move the mechanism to an open position in the absence of motor energization.
Abstract: For an automatic flue damper assembly of the type in which the motor of a clockwork mechanism is energized to hold the damper closed and the mechanism is mechanically biased to move the damper to an open position in the absence of motor energization, a stopping or braking arrangement is provided which applies DC to the motor for dynamic braking as the damper closely approaches its open position Additionally, the remote possibility of a damper hang-up at an intermediate position resulting from a residual magnetic locking torque is substantially eliminated through the provision of an AC trickle circuit connected to the motor
10 citations
24 Sep 2007
TL;DR: In this paper, a kind of regenerative braking system of an electric car is studied and the car's speed, acceleration, the hydraulic accumulator's pressure and volume were simulated with Matlab while the electric car was braking or accelerating from stop.
Abstract: A kind of regenerative braking system of an electric car is studied in the paper. The car's speed, acceleration, the hydraulic accumulator's pressure and volume are simulated with Matlab while the electric car is braking or accelerating from stop. The hydraulic accumulator can absorb all of the braking energy when braking and the energy stored in the hydraulic accumulator can drive the electric car to a certain speed so as to make the driving motor start with low current.
10 citations
Dissertation•
28 Mar 2013
TL;DR: In this paper, a model reference adaptive control (MRAC) for train dynamic braking is investigated in order to control dynamic braking forces while remaining within the allowable adhesion and coupler forces.
Abstract: The application of Model Reference Adaptive Control (MRAC) for train dynamic braking is investigated in order to control dynamic braking forces while remaining within the allowable adhesion and coupler forces. This control method can accurately determine the train braking distance. One of the critical factors in Positive Train Control (PTC) is accurately estimating train braking distance under different operating conditions. Accurate estimation of the braking distance will allow trains to be spaced closer together, with reasonable confidence that they will stop without causing a collision. This study develops a dynamic model of a train consist based on a multibody formulation of railcars, trucks (bogies), and suspensions. The study includes the derivation of the mathematical model and the results of a numerical study in Matlab. A threerailcar model is used for performing a parametric study to evaluate how various elements will affect the train stopping distance from an initial speed. Parameters that can be varied in the model include initial train speed, railcar weight, wheel-rail interface condition, and dynamic braking force. Other parameters included in the model are aerodynamic drag forces and air brake forces. An MRAC system is developed to control the amount of current through traction motors under various wheel/rail adhesion conditions while braking. Minimizing the braking distance of a train requires the dynamic braking forces to be maximized within the available wheel/rail adhesion. Excessively large dynamic braking can cause wheel lockup that can damage the wheels and rail. Excessive braking forces can also cause large buff loads at the couplers. For DC traction motors, an MRAC system is used to control the current supplied to the traction motors. This motor current is directly proportional to the dynamic braking force. In addition, the MRAC system is also used to control the train speed by controlling the synchronous speed of the AC traction motors. The goal of both control systems for DC and AC traction motors is to apply maximum available dynamic braking while avoiding wheel lockup and high coupler forces. The results of the study indicate that the MRAC system significantly improves braking distance while maintaining better wheel/rail adhesion and coupler dynamics during braking. Furthermore, according to this study, the braking distance can be accurately estimated when MRAC is used. The robustness of the MRAC system with respect to different parameters is investigated, and the results show an acceptable robust response behavior.
10 citations
Patent•
13 Mar 2003
TL;DR: In this article, a hydraulic servomotor has a master cylinder with a hydraulic piston defining a pressure chamber connecting to brake cylinders arranged at levels of wheels, where the front and rear chambers are filled with braking hydraulic fluid at the same pressure, provided by a hydraulic fluid source under high pressure.
Abstract: The device has a master cylinder (13) with a hydraulic piston (95) defining a pressure chamber (7) connected to brakes arranged at levels of wheels. A hydraulic servomotor (11) has a hydraulic piston (15) dividing a chamber (5) into front and rear chambers (51, 53). The front and rear chambers are filled with braking hydraulic fluid at same pressure, where the fluid is provided by a hydraulic fluid source under high pressure. An independent claim is also included for a braking system.
10 citations