Contents
What are the impacts of ripples in motor current in DC drives?
The voltage ripple results in unwanted speed regulation, unexpected mechanical vibration, and unwanted audible sound [7, 23]. It also affects the accuracy and rotor position (hall sensors) of the BLDC motor drive.
What are DC ripples?
Ripple (specifically ripple voltage) in electronics is the residual periodic variation of the DC voltage within a power supply which has been derived from an alternating current (AC) source. This ripple is due to incomplete suppression of the alternating waveform after rectification.
What is the function of starters in DC motor?
Starters are used to protect DC motors from damage that can be caused by very high current and torque during startup. They do this by providing external resistance to the motor, which is connected in series to the motor’s armature winding and restricts the current to an acceptable level.
What is the source of torque in a DC motor?
By turning on and off coils in sequence, a rotating magnetic field can be created. These rotating magnetic fields interact with the magnetic fields of the magnets (permanent or electromagnets) in the stationary part of the motor (stator) to create a torque on the armature which causes it to rotate.
What can increase the speed of a dc motor?
Increasing the speed can be achieved by increasing the supply frequency as the speed and frequency are directly proportional; however, there are two constraints. The first is the saturation of the magnetic circuit, but this issue can be significantly avoided by keeping the V/f ratio constant.
What are the effects of ripples in a DC Circuit?
The Ripple factor is the ratio of the ac voltage to the dc voltage. Effects of Ripples. Ripples can cause failure of components such as capacitors and can cause heating and failure in certain electronic components.
How does a ripple in supply affect a motor?
Given the inertial behavior of a typical motor, the ripple in supply will not cause significant adverse effect. The most noticeable effect, for really large ripple factors, would be an audible buzz at the ripple frequency.
What is the ripple factor of 10V DC?
Thus if we have 10V dc supply with a variation between 9.5 to 10.5 volts, the ripple factor would be (.5/5)*100 which indicates a ripple factor of 5%. The peak-to-peak value of the ripples at the output of a full wave rectifier is given by V pp =I/2 fC In the case of a half wave rectifier, the peak voltage is given by
How are ripples filtered in a DC rectifier?
The output of a rectifier produces a pulsating voltage, which rises from zero to maximum Vp and then to minimum. This voltage is not suitable to be used in electronics as it contains ripples. The ripples need to be filtered by a filter circuit which is usually a capacitor connected in parallel to the power source.