e-Learning in electrical engineering

Search | Navigation principles
Generalities Choppers Inverters Rectifiers Other converters

1. Structure and command

Lecture's plan

Introduction

  1. Structure and command
  2. Example of function to be achieved: the rectifier
  3. Example of function to be achieved: the inverter
  4. Example of function to be achieved: the chopper
  5. Problems to be solved

 

 

In a direct converter, the semiconductor switches, join the output terminals of the generator to the input terminals of the receiver (figure 1).

Figure 1

According to their state (ON or OFF), these switches establish or suppress the connections between these terminals.

The voltages, the currents and the power supplied by the generator to the receiver depend on the manner in which the connections established or suppressed by the semiconductor switches evolve in time.

The commutations of the semiconductors (changes from the ON state to the OFF state or from the OFF state to the ON state) result:

  • either from the evolution of the current that flows through them or from the voltage across their terminals, either from the commands that are applied to them

according to the semiconductors' type (diode, transistor, thyristor).

If there are controlled semiconductors we can act (via the command signals that are applied to them) on the evolution of the connections between the generator and the receiver (figure 2). But we have to look after that the connections that we establishe or that we open are compatible with the Kirchhoff's laws and with the energy's continuity in the L and C elements present in the generator and the receiver.

Figure 2

Site coordinator: Damien Grenier | Thematic coordinator: Francis Labrique | Realization: Sophie Labrique | © e-lee.net
Last update: 2005, September, 30 | Translation: Sergiu Ivanov