Overview:
A 3-phase dual converter is a power electronic device used for controlling the direction and magnitude of power flow between two 3-phase AC systems. It consists of two 3-phase full converters connected in antiparallel configuration.

Explanation:
To understand why option 'C' is the correct answer, let's first discuss the operation of a dual converter and the different configurations of full converters.

Dual Converter:
A dual converter is a bidirectional power electronic device that can transfer power in either direction between two 3-phase AC systems. It consists of two converters, namely rectifier and inverter, connected back-to-back.

During rectification mode, the rectifier converter converts AC power from one system into DC power. In the inverter mode, the inverter converter converts DC power back into AC power and feeds it to the other system. The switching pattern of the semiconductors in the converters determines the power flow direction.

Full Converter:
A full converter is a power electronic device that can convert both the magnitude and direction of power flow between two 3-phase AC systems. It consists of six bidirectional switches, usually implemented using insulated gate bipolar transistors (IGBTs), connected in a bridge configuration.

The four possible configurations of full converters are:
1. Two full converters connected in parallel
2. Two full converters connected in antiparallel
3. One full converter acting as rectifier and another as an inverter
4. One full converter acting as a rectifier and another as a chopper

Antiparallel Connection:
In the antiparallel connection, the output terminals of the two full converters are connected together, creating a common DC bus. One converter operates in the rectifier mode, while the other operates in the inverter mode. The antiparallel connection allows bidirectional power flow between the two systems.

When AC power is fed to the rectifier converter, it converts it into DC power, which is then supplied to the common DC bus. Simultaneously, the inverter converter takes DC power from the common DC bus and converts it back into AC power, which is fed to the other system.

The antiparallel connection of two 3-phase full converters allows for bidirectional power flow and provides control over the magnitude and direction of power transfer. This makes it suitable for applications such as electric vehicle chargers, renewable energy systems, and industrial motor drives.

Therefore, option 'C' - "two 3-phase full converters connected in antiparallel" - is the correct answer for the configuration of a 3-phase dual converter.

Introduction:
A dual converter is a type of power electronic converter that allows bidirectional power flow between two AC systems. It is commonly used in applications where power transfer and control in both directions are required. A 3-phase dual converter consists of two 3-phase converters connected together to achieve this bidirectional power flow.

Explanation:
The correct answer for the given question is option 'c', which states that a 3-phase dual converter consists of two 3-phase full converters connected in antiparallel. Let's understand why this is the correct answer:

1. Two 3-phase full converters:
A full converter is a type of power electronic converter that allows bidirectional power flow between an AC system and a DC system. It consists of six controlled switches (thyristors) arranged in a bridge configuration. In a 3-phase full converter, three full converters are connected together to form a 3-phase bridge. Therefore, a 3-phase dual converter requires two such 3-phase full converters to function.

2. Connected in antiparallel:
The two 3-phase full converters in a 3-phase dual converter are connected in antiparallel configuration. This means that the AC terminals of one converter are connected to the DC terminals of the other converter, and vice versa. This configuration allows bidirectional power flow between the AC systems connected to each converter.

3. Bidirectional power flow:
The antiparallel connection of the two full converters in a 3-phase dual converter enables bidirectional power flow between the two AC systems. When the input AC system supplies power, one full converter acts as a rectifier and converts the AC power into DC power. Simultaneously, the other full converter acts as an inverter and converts the DC power back into AC power, which is fed back into the AC system.

Advantages of the antiparallel connection:
- Allows bidirectional power flow between the two AC systems.
- Provides flexibility in controlling power flow and voltage levels.
- Enables regenerative braking, where the energy from a motor or load can be fed back into the AC system.
- Reduces the need for external components, as the two full converters can share common components such as filters and DC bus capacitors.

Conclusion:
In conclusion, a 3-phase dual converter consists of two 3-phase full converters connected in antiparallel. This configuration enables bidirectional power flow between two AC systems and offers advantages such as flexibility in power control and regenerative braking.