What is pwm rectifier circuit, and what is the difference between it and phase-controlled rectifier circuit in working principle and performance?

PWM rectifier circuit is composed of PWM control mode and fully controlled devices.

First of all, the principle is different:

1, PWM rectifier circuit:

SPWM control technology in inverter circuit is applied to rectifier circuit to form PWM rectifier circuit.

2. Phase-controlled rectifier circuit:

Rectification control is carried out by controlling the number of phases input at the AC side.

Second, the performance is different:

1, PWM rectifier circuit:

It can solve the problems existing in the traditional rectifier circuit to varying degrees. By controlling the PWM rectifier circuit, the input current is very close to sine wave and in phase with the input voltage, and the power factor is about 1.

2. Phase-controlled rectifier circuit:

In this circuit, the average value of DC load voltage can be controlled as long as the phase angle of thyristor is properly controlled at the moment of triggering conduction.

Extended data

Principle structure:

Similar to the output voltage controlled by SPWM inverter circuit, sine wave modulated PWM wave uAB can be generated between AC input terminals AB of PWM rectifier circuit. UAB contains not only the fundamental component which is the same as the power supply frequency, but also the higher harmonics related to the switching frequency.

Due to the filtering effect of inductance Ls, these high-order harmonic voltages will only cause small pulsation of AC current is. If this pulsation is ignored, it is a sine wave with the same frequency as the power supply. When the AC power supply voltage us is constant, the amplitude and phase of IS are determined by the amplitude of the fundamental component in uAB and its phase difference with us. By changing the amplitude and phase of the fundamental component in uAB, is and us can be in phase.