Three phase bridge rectifier using 20L6P45.

Three phase full wave rectifier circuit is an advanced power rectifier circuit mostly used for industrial DC applications. This module basically has 3 phase inputs and a single DC output. Most of the industrial power supplies such as DC motor drives, welding units, etc are used these kinds of rectification unit. A simple 3 phase rectifier circuit (using20L6P45) and its specifications are given below.

Three phase system: In a three phase system there will be three conductor wires carrying three alternating currents which attain their peak magnitudes at different times. The frequency of the current in each wire will be the same but they are separated by a fixed amount of time. A neutral wire may be also included in the system and it improves the flexibility of the system because the load can be connected phase to phase or phase to neutral.

three phase rectifier diagram
3-Phase wave form, before & after rectification.


The20L6P45 full wave bridge rectifier module is an advanced 3 Phase silicon diffused type power rectifier which helps to rectify the 3phase AC input to a single DC output with an efficiency more than 90%. This module can handle maximum power of 20A. These module integrated the basic 3 Phase diode rectification unit itself by the silicon diffusion technology.

Structure of20L6P45.

rectifier module internal diagram
Internal structure of 20L6P45

The internal structure of20L6P45 full wave bridge rectifier is given in the picture above. As in the structure, we can see that its internal structure of20L6P45 is similar to the 3 phase diode bridge rectification unit, But the main advantage is, 20L6P45 chip only taken less space, simpler, less weight, high efficiency, high voltage and current rating, etc.

Circuit diagram.

three phase rectifier
Three phase rectifier circuit

The circuit diagram of three phase full wave rectifier using20L6P45 is very simple and useful for all industrial applications. The input of this module is 3 Phase AC (50-80Hz) and the output is LC filtered DC (which provide pure DC at the output).This rectifier can be used for a wide range of AC inputs (50v-450v) and maximum current of 20A.The output of this circuit contain a π section LC filter unit (serial connection of capacitor helps to improve its voltage rating) , which provide High efficient low ripple DC at the output. According to the usage, you can vary the voltage and capacitance for this circuit. If you want more current rating, connect an additional rectifier module parallel to the chip. This circuit also needs proper Heat sink for absorbing excess heat. The circuit diagram for this rectifier is give below. (If this module is not available in your area, you can  also use 20U6P45 module).

Electrical characteristics.

specifications of 20L6P45
20L6P45 electrical characteristics


Applications of 20L6P45 Rectifier module are given below.

  • Three phase Full wave Bridge applications.
  • Used as an inverter for AC motor control.
  • Chopper equipment for DC motor controller
  • DC supply for battery
  • Other power conversion equipments.


  1. krishna veni

    how much ripple frequency used in 3-phase bridge rectifier?

  2. its working with the peak load of 20A 230v three phase and maximum torque rate of 1.2 Nm at 25 degree cel.