How to control the speed of DC motor using PWM ?

How to control the speed of DC motor using PWM ?

How to control the speed of DC motor using PWM ?A DC motor is a type of rotary electric motor that converts electricity into electric current. It is usually a magnetic field that generates total energy. Almost all types of DC motors, both motor and electric, have several internal modes that change the direction of motor current from time to time.

There are many different ways to control the speed of DC motors, but a very simple and easy way is to use Pulse Width Modulation.

 Pulse Width Modulation :

               Pulse Width Modulation is commonly used to control the speed of DC motor. It is defined as the percentage of digital “high” to digital “low” plus digital “high” pulse-width during a PWM period. PWM is a method of reducing the average delivered by an electrical signal into discrete parts. The average value of voltage fed to the load is controlled by turning the switch between supply and a load.

When the equipment rotates, the current from the power plant passes through the carbon brushes next to the switch to the next anchoring station, which creates additional gravity, and whenever the hand rotates the anchoring station, the new anchorage is amplified, forcing the military to walk More and more. More and more around.

Therefore, the speed of a DC motor depends on the interaction of two magnetic fields, one of which is provided by the permanent stator market, and the other magnetic field controls the speed of the circuit by rotating the electromagnet and controlling this interaction.

Then, the rotational speed of the DC motor (N) is proportional to the rear EMF (Vb) of the motor divided by the magnetic current (which is constant for the permanent magnet) multiplied by the electromechanical constant, depending on the nature of the motor. winding. (Ke), which gives us the equation: N ∝ V / KeΦ.

So how do we deal with electricity and electricity? Many have pointed out that DC using variable resistor (rheostat) is an attempt to control the speed of a DC motor, as shown below :


speed of DC motor
speed of DC motor

It can run smoothly and, like an engine, block electricity and electricity. One of the simplest and easiest ways to control the speed of a machine is to control the power of the system, which can be operated by “pulse width modulation” or PWM.

As the name implies, pulse amplifier speed control works by running the motor with a “ON-OFF” pulse and changing the duty cycle. This is a fraction of the time the output voltage is on. If “Closed”. “, Maintaining a constant frequency.

When the device is turned on, electrical energy is transferred from the vehicle to special stone boxes and carbon brushes placed near the blade, which gives great power to the company, and from time to time the tool turns, even with new cassette tapes. more and more and so on.

The power to the motor can be controlled by changing the application of pulses, thus changing the average DC current supplied to the motor. By changing or adjusting the time for these pulses, the engine speed can be controlled. The longer the pulse runs, the faster the speed of the motor. The shorter the “on” time of the pulse, the slower the speed of the motor.

In other words, if my heart rate is high, place a higher average voltage on the top of the vehicle, and the higher the magnetic velocity of the weapon, the faster the car equipment, lower the car as follows:


The advantage of using a pulse-width model to control the body so that small changes in the electric field transistor is small because the transistor is “on” or “off” level. For this reason, the more the power of the power consumption and offers salvation to the administration of the transformer is greater than those beneath.

In addition the voltage of the electric motor will remain constant, which makes the motor extremely powerful. The result is that the engine can run slowly without stopping. So how can we create a signal to change the heart rate to control the motor. Diode is used to favor the freewheeling diode and to protect the electronic circuit from the inductive loading of the motor. Also if the motor load is high put a heatsink on the switching transistor.

Pulse width modulation is a great way to adjust the amount of energy delivered by an electric charge without melting unwanted energy. The upper circuit can also be used to adjust the fan speed and reduce the brightness of DC or LED lamps. If you want to control it, use pulse width modulation to control it.

Also read here


How to interface DC motor with PIC microcontroller?

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