Electric bicycle controllers generally use brake application sensors, pedal rotation sensors and provide potentiometer-adjustable motor speed, closed-loop speed control for precise speed regulation, protection logic for over-voltage, over-current, and thermal protection.
Computer-programmable speed controls generally have user-specified options which allow setting low voltage cut-off limits, timing, acceleration, braking and direction of rotation. A higher number of cells connected will result in a reduced power rating and therefore a lower number of servos supported by an integrated BEC, if it uses a linear voltage regulator.
ESCs used in mass-produced electric cars with AC motors usually have reversing capability, allowing the motor to run in both directions. Pedal pressure sensors under the feet are possible but not common. The rapid switching of the transistors is what causes the motor itself to emit its characteristic high-pitched whine, especially noticeable at lower speeds.
Function[ edit ] An electronic speed control follows a speed reference signal derived from a throttle lever, joystick, or other manual input and varies the switching rate of a network of field effect transistors FETs. The ESC forces the motor to act as a generator by placing an electrical load across the armature.
Some custom-built electric cars with DC motors also have this feature, using Speed control of dc motor thesis electrical switch to reverse the direction of the motor, but others run the motor in the same direction all the time and use a traditional manual or automatic transmission to reverse direction usually this is easier, since the vehicle used for the conversion already has the transmission, and the electric motor is simply installed in place of the original engine.
DC motors also cannot safely run at RPMs as high as AC motors can, so many custom-built electric cars retain a multi-speed transmission of some kind. Sometimes pedal torque sensors are used to enable motor assist proportional to applied torque and sometimes support is provided for regenerative braking but infrequent braking and the low mass of bicycles limits recovered energy.
The car has only one gear ratio, and the motor simply runs in the opposite direction to make the car go in reverse. Since electric motors have full torque from zero RPM, the vehicle can still start off in a high gear, but starting in a lower gear allows for quicker acceleration, lower current draw and less wear and tear on the motor.
This in turn makes the armature harder to turn, thus slowing or stopping the model. In some cases it is possible to change the factory built-in firmware for an alternate, publicly available, open source firmware. If the power coming from the battery is insufficient to continue running the electric motor the ESC will reduce or cut off power to the motor while allowing continued use of aileronsrudder and elevator function.
Brushless motors are popular with radio controlled airplane hobbyists because of their efficiency, power, longevity and light weight in comparison to traditional brushed motors.
Electric bicycles[ edit ] Electronic bicycle A motor used in an electric bicycle application requires high initial torque and therefore uses Hall sensor commutation for speed measurement.
The energy draw is usually measured in kilowatts the Nissan Leaf, for instance, uses an 80 kilowatt motor that produces foot-pounds of torque. Different types of speed controls are required for brushed DC motors and brushless DC motors.
Generally the higher the rating, the larger and heavier the ESC tends to be which is a factor when calculating mass and balance in airplanes. It is also used in quadcopters. Quadcopters[ edit ] Electronic Speed Controllers ESC are an essential component of modern quadcopters and all multirotors that offer high power, high frequency, high resolution 3-phase AC power to the motors in an extremely compact miniature package.
Some controllers add the benefit of regenerative braking. Many modern ESCs support nickel metal hydridelithium ion polymer and lithium iron phosphate batteries with a range of input and cut-off voltages. Some ESCs are factory built with the capability of user upgradable firmware.
This is done generally to adapt the ESC to a particular application. Most marine-grade ESCs are cooled by circulated water run by the motor, or negative propeller vacuum near the drive shaft output. The watertight structure is significantly different from that of non-marine type ESCs, with a more packed air trapping enclosure.
Brushless AC motor controllers are much more complicated than brushed motor controllers. Thus arises the need to cool the motor and ESC effectively to prevent rapid failure.
The type of battery and number of cells connected is an important consideration when choosing a battery eliminator circuit BECwhether built into the controller or as a stand-alone unit. However it is usually easier to increase the motor size so that the maximum torque is acceptable since the weight of a transmission can be equal to the motor.
A well designed BEC using a switching regulator should not have a similar limitation. Boats[ edit ] ESCs designed for boats are by necessity waterproof. These craft depend entirely on the variable speed of the motors driving the propellers. Others require soldering to connect a programmer.
In others, such as the Nissan Leaf, there is only a slight "drag" effect when coasting, and the ESC modulates the energy capture in tandem with the conventional brakes to bring the car to a stop.Abstract.
DC Motor speed control is carried out by use of Four Quadrant Chopper drive. Insulated Gate Bipolar Transistors are used for speed control of the motor and the IGBT triggering is carried out by use of PWM converters under various loading conditions and by varying armature voltage and field voltage.
DESIGN AND ANALYSIS OF SPEED CONTROL USING HYBRID PID-FUZZY CONTROLLER FOR INDUCTION MOTORS. by. Ahmed Fattah. A thesis submitted to the Graduate College. A Thesis. entitled.
A Study of Control Systems for Brushless DC Motors. by. separately excited DC motor. The speed vs. torque characteristic of a BLDC using a PI controller is also discussed. To my parents, family and friends.
v. Acknowledgements. Thesis Organization.
An electronic speed control or ESC is an electronic circuit that controls and regulates the speed of an electric motor. It may also provide reversing of the motor and dynamic braking.
Miniature electronic speed controls are used. Sensors.
sensor for brushless motor control is given in Figure 2 first alignment is between the b. A rotor orientation and the permanent magnet, and a second alignment is between the stator and the sensor.
An Introduction to Brushless DC Motor Control By Steven Keeping Contributed By Electronic Products The brushless DC (BLDC Precise timing allows for accurate speed and torque control, as well as ensuring the motor runs at peak efficiency.Download