Multi Quadrant Operation Of DC Motor Fed From Fully Controlled Rectifier, Dual Converter, Field Reversal

Hello guys, welcome back to my blog. In this blog, I will discuss the multi quadrant operation of dc motor fed from a fully controlled rectifier, dual converter, and field reversal. Each and everything I will try to explain in a simple way.

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Multi Quadrant Operation Of DC Motor


What is a multi quadrant operation?

The multi quadrant operation means making the motor to operate in four quadrants such as forward motoring, forward braking, reverse motoring, reverse braking, etc.

Multi Quadrant Operation Of DC Motor


Multi Quadrant Operation Of DC Motor Fed From Fully Controlled Rectifier, Dual Converter, Field Reversal

A fully controlled rectifier feeds the motor through a reversing switch RS which is used to reverse the armature connection with regard to the rectifier. A fully-controlled rectifier is able of providing operation in quadrants one and fourth. The reversal of the armature connection provides operation in quadrant third and second. The reversing switch may consist of a relay operated contactor with two normally open and two normally closed contacts as shown in the above figure. When slow operation and regular maintenance associated with the contactor are not acceptable, the reversing switch is realized using from thyristor as shown in the above figure.

With thyristor pair, Tf on, and pair Tr off we can obtain operation in quadrant one and four. With pair Tr on and Tf off, we can obtain operation in the third and second quadrant. In both the configurations of RS, the switching is done to zero current in order to avoid voltage spikes and to reduce its rating.

Multi Quadrant Operation Of DC Motor Fed From Dual Converter

Multi Quadrant Operation Of DC Motor Fed From Fully Controlled Rectifier, Dual Converter, Field Reversal

The dual converter the name itself means that it has two converters in it. It is an electric device mostly found in variable speed drives. It is a power electronics control system to get either polarity DC from AC rectification by the forward converter and reverse converter. In a dual converter, two converters are connected together back to back.


One of the bridge works as a rectifier (converts AC to DC), another bridge works as an inverter (converts DC to AC) and connected commonly to a DC load. Here two conversion processes take place simultaneously, so it is called a dual converter. The dual converter can provide four-quadrant operations.

Rectifier A which provides positive motor current and voltage in either direction allows motor control in quadrant one and four. Rectifier B provides motor control is quadrants third and four because it gives negative motor current and voltage in either direction.

Four Quadrant Drive With Field Reversal

Multi Quadrant Operation Of DC Motor Fed From Fully Controlled Rectifier, Dual Converter, Field Reversal

Four quadrants drive with field reversal as shown in the above figure. The armature is fed from a fully-controlled rectifier and the field from a dual converter so that field current can be reversed. With field current in one direction, the motor operates in quadrant one and four. When the field current is reversed it operates in quadrant third and second.

I hope this article may help you all a lot. Thank you for reading.
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