Contents
What is circulating current in dual converters?
Circulating Current Mode Converter 1 performs as a controlled rectifier when firing angle be 0<α1< 90o and Converter 2 performs as an inverter when the firing angle be 90o<α2< 180o. In this condition, Vdc and Idc are positive.
What is the function of circulating current reactor in dual converter?
Explanation: Reactor (inductance) is added in circulating current mode between both the converters. The reactor limits the current to a reasonable value.
Which of the following are the modes of operation in case of dual converters?
The schematic diagram of the dual converter is shown below.
- There are two functional modes: Non-circulating current mode and Circulating current mode.
- One converter will perform at a time.
- During the converter 2 operation, 0 < α2 < 90°; Va and Ia are negative appear in 3rd quadrant.
How does the DC circulating current can be controlled in dual converter fed drives?
In a three-phase dual converter, inductors are chosen to allow a circulating current of 30% of full load current. This completely eliminates discontinuous conduction, and therefore, gives good speed regulation in the complete range of the drive.
What is a circulating current?
Circulating currents are a result of an asymmetry in the motor and the voltage it creates between the stator and rotor iron, but not related to the motor drive or method used to drive the motor. Each motor winding has slight variations as compared to the other windings.
What happens if there is no circulating current in dual converter?
In a dual converter without circulating current operating mode, the flow of circulating current is completely inhibited through automatic control of the firing pulses, so that only that converter which carries the load current is in conduction and the other converter is temporarily blocked.
What do you mean by circulating current?
When two substations are conected through a switch, there may be a voltage difference between the sites. When the switch is closed, creating a parallel, it is said that current flows between the sub stations, known as ‘circulating current’.
What is circulating current in power electronics?
Module synchronization- All inverter module connected in parallel should have the same output voltage, frequency and phase. If the output voltage of modules are not equal a current flow from the module with the higher voltage to the lower voltage that current is known as crosscurrent or circulating current.
What is the name of mode when both rectifier in dual converter are working simultaneously?
Circulating Current Mode
Circulating Current Mode In this mode, both converters will be in the ON condition at the same time. So circulating current is present. The firing angles are adjusted such that α1+ α2=1800.
What are circulating currents in transformer?
The current is proportional to the voltage difference between the transformers divided by the sum of the impedances around the circulating path. For a two- transformer substation, the circulating currents in each transformer are equal in magnitude and opposite in direction.
How do you calculate circulating current?
Conceptually, it really is as simple as Ohm’s Law: I = V/R. Of course that is an over simplification, but it is the same concept applied to three phase AC systems. Now let’s take a deeper dive into how to calculate circulating current.
What is the name of mode when both rectifier in dual converters are working simultaneously?
What are the two modes of dual converter?
Modes of Operation of Dual Converter There are two functional modes: Non-circulating current mode and circulating mode. Non Circulating Current Mode One converter will perform at a time.
How does a dual converter control circulating current?
There are two Modes to control the circulating current. In this type of dual converter, only one converter is in conduction and another converter is temporarily blocked. So, at a time one converter operates and the reactor is not required between the converters.
How many quadrants can a dual DC converter do?
Here, two full converters are arranged in anti-parallel pattern and linked to the same dc load. These converters can provide four quadrant operations. The basic block diagram is shown below. There are two functional modes: Non-circulating current mode and circulating mode. One converter will perform at a time.
What is the output voltage of a dual converter?
The average output voltage of the converter 1 is V 01 and converter 2 is V 02. To make the output voltage of the two converters in same polarity and magnitude, the firing angles of the thyristors have to be controlled. The firing angle can never be greater than 180 o. So,