68 results about "Three phase pwm rectifier" patented technology

The invention discloses a soft-switch three-phase PWM (Pulse Width Modulation) rectifier with an auxiliary free-wheel channel. The soft-switch three-phase PWM rectifier comprises a three-phase bridge arm consisting of 6 total-control main switches respectively provided with antiparallel diodes and parallel capacitors, input filtering inductors connected between the middle points of each phase of bridge arm and an AC power grid, and an output capacitor connected to the output terminal of the three-phase bridge arm, wherein the total-control switches with both the antiparallel diodes and the parallel capacitors are connected or not connected to two ends of the three-phase bridge arm; an auxiliary switch with both antiparallel diodes and parallel capacitors is connected between a DC bus and the output capacitor of the three-phase bridge arm; and resonance branch circuits consisting of both resonance inductors and clamping capacitors are connected to two ends of the auxiliary switch in a bridging manner. The soft-switch three-phase PWM rectifier has a simple structure, and can inhibit reverse restoration of diodes and reduce electromagnetic interference. All switch devices of the rectifier achieve zero-voltage switch-on, have small loss and high circuit efficiency, facilitate improving the operating frequency and further improve the power density. The rectifier provided by the invention realizes output capacity and voltage control and achieves the power factor correction function of input current.

The invention provides a three-phase PWM rectifier control method which includes a direct current capacitor energy storage outer loop control method and a grid-side current inner loop control method. The method includes the steps that direct current capacitor stored energy of a rectifier is fed back as a whole, given capacitor charging power is output after calculation is finished through an energy PI adjuster, grid-side input power is obtained by adding load power to the given capacitor charging power, a given grid-side d-axis current value i*d is obtained by dividing grid-side input power by the grid-side d-axis voltage component, a given q-axis current value i*q is obtained according to the relation between given d-axis current and given q-axis current, a grid-side voltage control value ud and a grid-side voltage control value uq are obtained in sequence according to the grid-side current inner loop control method, given voltage values are obtained through feedforward and decoupling of the ud, uq and the network voltage, given phase voltage output values are obtained through Park inverse transformation and Clark inverse transformation, and switch control signals Sa, Sb and Sc used for driving a PWM rectifier bridge arm electronic switch are obtained finally through space vector pulse width modulation. By means of the method, the dynamic response performance of a three-phase PWM rectifier can be improved greatly, and the method is particularly suitable for fast charging of electric cars and other occasions having high requirements for the response performance of the three-phase PWM rectifier.

The invention discloses a tovel triangular wave comparison control method for a three-phase PWM rectifier, and belongs to the power electronic converting technology and intelligent control field; the control method mainly comprises a voltage outer ring, a feedforward decoupling, and triangular wave comparison control; the voltage outer ring is a PI node, and the feedforward decoupling is current inner ring control. The control method is simple, uses advantages of the triangular wave comparison control and the feedforward decoupling, and can realize constant frequency control and AC side input current low resonance when an input power factor is 1 and a switch frequency is low.

The invention discloses a three-phase PWM rectifier control method and system. The three-phase PWM rectifier control method comprises the steps: aiming at any moment, operating parameters of an alternating-current power grid are obtained; the mechanical torque, excitation flux linkage and the alternating-current power grid angle rotating speed are calculated according to the operating parameters;the torque ptotic amount is calculated according to the alternating-current power grid angle rotating speed and the virtual rotating speed; the electromagnetic torque is calculated according to a three-phase current, the electric angle and the excitation flux linkage; the new virtual rotating speed is calculated according to the electromagnetic torque, the mechanical torque and the torque ptotic amount and serves as a feedback input value for calculating the torque ptotic amount of the next moment; the new electric angle is calculated according to the new virtual rotating speed and serves as afeedback input value for calculating the electromagnetic torque of the next moment; the virtual counter electromotive force is calculated according to the new electric angle, the new virtual rotatingspeed and the excitation flux linkage; and a modulating wave signal is calculated according to the virtual counter electromotive force. Under the situation of the stable state, the output voltage andpower can stably follow set values, and support is provided when the power grid fluctuates.