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Due to the absence of freewheeling diodes, the power circuit is reduced in size and weight, and tends to be more reliable than VSIs. [18] Although single-phase topologies are possible, three-phase CSIs are more practical. In its most generalized form, a three-phase CSI employs the same conduction sequence as a six-pulse rectifier.
Diagram of a simple circuit with an inductance L and a flyback diode D.The resistor R represents the resistance of the inductor's windings. A flyback diode is any diode connected across an inductor used to eliminate flyback, which is the sudden voltage spike seen across an inductive load when its supply current is suddenly reduced or interrupted.
The additional PN junction blocks reverse current flow. This means that unlike a MOSFET, IGBTs cannot conduct in the reverse direction. In bridge circuits, where reverse current flow is needed, an additional diode (called a freewheeling diode) is placed in anti-parallel with the IGBT to conduct current in the opposite direction. The penalty isn ...
To implement the current injection technique, current injection circuit was developed with results indicating that the injection of an additional current during its switching transient can reduce the reverse recovery charge of a given power diode and thyristor, and also reduce the tail current of insulated gate bipolar transistors.
If the AC supply is fed via a transformer with a center tap, a rectifier circuit with improved harmonic performance can be obtained. This rectifier now requires six diodes, one connected to each end of each transformer secondary winding. This circuit has a pulse-number of six, and in effect, can be thought of as a six-phase, half-wave circuit.
Bridge rectifier (four diodes in a package) often changed to "D" for diode BT, BAT: Battery or battery holder: often shortened to "B" C: Capacitor: CB: Circuit breaker: CN: Capacitor network: may be simplified to "C" for capacitor D, CR: Diode (all types, including LED), thyristor "D" is preferred for various types of diodes DL: Delay line: DN ...
Early solid-state pinball machines made use of these to control lights, solenoids, and other functions electronically, instead of mechanically, hence the name solid-state. Other applications include power switching circuits, controlled rectifiers, speed control of DC shunt motors, SCR crowbars, computer logic circuits, timing circuits, and ...
Whereas normal semiconductor diodes have a roughly fixed voltage drop of around 0.5 to 1 volts, active rectifiers behave as resistances, and can have arbitrarily low voltage drop. Historically, vibrator -driven switches or motor-driven commutators have also been used for mechanical rectifiers and synchronous rectification.