How can separately excited dc motor be controlled using a chopper?

The speed of Separately Excited DC motor is controlled to a maximum of its rated speed using chopper as a converter. The speed controller used is Proportional Integral type which reduces steady state error and provides fast control. The parameters of the speed controller have been designed using control system theory.

How can you control the speed of a separately excited dc motor?

The speed of separately excited dc motor can be control by changing the armature voltage and changing field flux. Due to this the speed can be controlled for below rated speed and speed above the rated speed, respectively.

What is chopper controlled dc drives?

A dc chopper is a static switch to provide variable dc voltage from a source of constant dc voltage. Choppers are now being used all over the world for rapid transit systems. These are also employed in trolley cars, marine hoists, forklift trucks and mine haulers.

How a chopper can be used to control speed of a dc motor?

Chopper can be used as a converter to control the speed of separately excited DC motor. The speed control can be achieved above or below the rated speed. Controller receives the signal from the chopper firing circuit and then the chopper gives variable voltage to the armature of the motor for achieving desired speed.

How does a separately excited DC motor work?

A separately excited dc motor is a motor whose field circuit is supplied from a separate constant-voltage power supply, while a shunt dc motor is a motor whose field circuit gets its power directly across the armature terminals of the motor.

What kind of control system can be used in the field circuit of the separately excited DC motor at the breaking process?

The traditional buck chopper is used in many works as in [7, 8, 9, 10, 11, 12]. In this work, a series multi-cells chopper structure is used to control the separately excited DC motor.

What is a separately excited DC motor?

What is separately excited DC generator?

A separately excited DC generator is the one whose field winding is supplied by an independent external DC source (like a battery). The magnitude of generated voltage depends upon the speed of rotation of armature and the field current, i.e., greater the speed and the field current, higher is the generated voltage.

How does a chopper fed DC drive work?

The variable voltage to the armature of a dc motor for speed control can be obtained from a dc chopper which is a single stage dc to dc conversion device. The voltage variation at the load terminals can be obtained by using either current limit control or time ratio control.

Which chopper is used for motoring operation of a DC motor?

Motoring Control : A transistor Chopper Control of Separately Excited DC Motor drive is shown in Fig. 5.41(a). Transistor Tr is operated periodically with period T and remains on for a duration ton. Present day choppers operate at a frequency which is high enough to ensure continuous conduction.

What is separately excited?

Definition of separately excited : having the field magnets excited by a current from a separate source —used of a machine.

What is the advantage of separately excited DC motor?

Separately excited DC generators have many advantages over self-excited DC generators. It can operate in stable condition with any field excitation and gives wide range of output voltage. The main disadvantage of these kinds of generators is that it is very expensive of providing a separate excitation source.

What is separately excited and self excited?

In a separately excited (S.E.) machine, the field winding is connected to a separate voltage source while, in a self excited generator field winding is connected across the armature terminals (provides its exciting current) .

What is separately excited DC motor?

How does a DC chopper work?

DC chopper works on DC voltage. They work as a step up and step down transformers on DC voltage. They can convert the steady constant DC voltage to a higher value or lower value based on their type. DC choppers are more efficient, speed and optimized devices.

What are the control strategies of chopper?

There are two kinds of control strategies used in DC choppers namely time ratio control and current limit control.

What are the types of control strategies used in a chopper fed DC drive?

What are the different control techniques employed in chopper Fed drives?

There are various types of speed control techniques are available for DC drives, such as, armature voltage control, field flux control and armature resistance control. For controlling the speed and current of DC motor, speed and current controllers are used [5].

Which type of chopper is used in the forward motoring and regenerative braking of DC motors?

Explanation: It is a type C chopper or Two quadrant type A chopper. It operates in the first and second quadrant.

What is the chopper control of separately excited DC motor drive?

Motoring Control : A transistor Chopper Control of Separately Excited DC Motor drive is shown in Fig. 5.41 (a). Transistor T r is operated periodically with period T and remains on for a duration t on. Present day choppers operate at a frequency which is high enough to ensure continuous conduction.

What is the function of the chopper in DC Circuit?

The chopper converts the fixed DC voltage to variable DC voltage. Self-commutated devices (directly on or off devices via gate) like MOSFET, IGBT, power transistors, GTO and IGCT are used for making choppers because they can be commutated by low power control signal and do not need commutation circuit.

How to control the speed of a separately excited motor?

This method of sensing the speed of a separately excited DC motor employing variable voltage to the armature is used in different applications to control the amount of speed. The effect of the field current change on the speed-torque feature is another method used for speed control.

What is speed-torque characteristic of a separately excited DC motor?

The main formulation of a speed-torque Characteristic of a separately excited DC motor whose armature, including a total of Z con­ductors, is wound for 2P poles (the brushes separate the winding into 2 parallel paths), is and K e and K t are constants.