3 Phase Rectifier – Half Wave and Full Wave
A 3Φ Rectifier is an electronic circuit that converts three-phase AC supply into unidirectional DC output. 3 phase rectifiers are mainly used in industrial and high power applications.
In a three-phase electric power, an alternating current of the same frequency and voltage amplitude are carried through three conductors with a phase difference of 120 o degrees between each phase. Whereas a single phase supply is one of the three phases with respect to a neutral or common reference point of the 3 phase lines.
In three phase rectification, the output is obtained from the three phases fed into the rectifier circuit.
3 Phase Half Wave Rectifier
Here in the circuit 3 phase are connected to the anode of three diodes D1, D2, and D3. The cathode of all three diodes is connected to the one terminal of the load. The other terminal of the load is connected to the neutral. Hence, the maximum output voltage across the load is the maximum peak voltage of the phase line with respect to the neutral point which is ideally zero volts.
The diodes D1, D2, D3 alternatively conducts in respective to the phase change. The instantaneous output voltage will be equal to the voltage of the phase line which has the highest potential.
Three Phase Full Wave Rectifier
The above 3 phase bridge rectifier circuit consists of six diodes. In a full wave rectifier, the voltage across the load is the voltage between two phases.
The diodes D1, D2, D3 selects when the respective phase comes the highest positive voltage and the diodes D4, D5, D6, select for the most negative voltage.