Three-phase Diode Bridge Research Articles

A multilevel-voltage source rectifier with a three-phase diode bridge circuit as a main power circuit

A novel system obtaining very low distorted waveforms of input AC currents of three-phase rectifier circuits are proposed. The proposed rectifier system consists of a three-phase diode bridge circuit as a main power circuit, AC reactors, and an additional circuit which serves as an active filter with low switching frequencies and a forced-commutation circuit for the diodes. This paper describes the operation principle, analysis of the waveforms of input voltage and current, multiple phase-shifted systems, and the experimental results. The proposed system gives excellent input current waveforms and has many advantages over conventional systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A Harmonic Analysis of Three-Phase Rectifier with a DC Filter Capacitor.

In most voltage-fed inverter drives, three-phase diode bridge rectifiers with a filter capacitor at the DC side are often used. In this type of rectifier, the harmonic levels of the line current are well known to be quite high. So far, a time simulation method has been used to analyze the harmonic current. This method is very accurate, but it requires a long computing time and a complicated algorithm.This paper proposes a practical new method to easily calculate the harmonic currents for both the continuous and discontinuous current conductions. The proposed method is based on the frequency domain method and the rectifier switching functions. Analytical equations for the harmonic currents on both the DC and AC sides are derived, taking into account the effects of filter capacitance and line reactance. All the calculations are conducted only by algebraic calculation with high accuracy. The effectiveness of the proposed method is confirmed by comparison with the results obtained by the simulation method.

Harmonic current reduction in industrial distribution networks

Non-linear loads such as bridge rectifiers produce harmonic currents in AC systems. This paper presents a novel method for reducing these harmonics. The scheme has been analysed, simulated and tested for the case of a three-phase diode bridge rectifier supplying a DC motor load.

Calculation of Uncharacteristic Harmonics Generated by Three-Phase Diode-Bridge Rectifier with DC Filter Capacitor.

Three-phase diode-bridge rectifiers are used to convert the AC input into DC voltage. A large capacitor is connected as a filter on the DC side, since in most applications, a low ripple in the DC output voltage is desirable. Unbalance in the supply conditions of a three-phase diode-bridge rectifier with a DC filter capacitor gives rise to uncharacteristic harmonics on both the AC and DC sides.This paper proposes a simplified method for calculating the uncharacteristic harmonic currents generated by the three-phase diode-bridge rectifier under unbalance, taking into account the effects of both the AC and DC side impedances. Analytical expressions for the harmonic currents are derived using the switching functions with overlap period the AC circuit theory. Therefore, the proposed method can be executed only with algebraic computation and its accuracy is quite high. The validity of the proposed method is demonstrated by comparison with the results of time simulation.

Time domain circuit analysis

The program Power Electronic Circuit Analysis (PECAN), which has been made to handle some power engineering applications not suited for SPICE or EMTP, is discussed. Time functions of voltages, currents, torque, angular speed, power, and other derived quantities can be calculated and plotted on the screen a printer, or a plotter. The calculations are performed stepwise for a series of points in times, with a variable step size selected by the program within specified limits. Control functions can be converted to equivalent electrical circuits and can be included or studied separately. The program runs under MS-DOS on a personal computer with at least 640 kbytes of memory and a math coprocessor. Input files are provided with the program for many typical problems in power electronics, machine analysis, and others. The program can handle circuits with up to 300 components and 200 variables (nodes plus branches). Examples presented include pulse width modulation (PWM), three-phase diode bridge, symmetrical three-phase short circuit of synchronous generator, and transient temperatures on cables.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Proposal of a Multilevel-Voltage Source Type Rectifier Having a Three-Phase Diode Bridge Circuit as a Main Power Circuit.

Proposal of a Multilevel-Voltage Source Type Rectifier Having a Three-Phase Diode Bridge Circuit as a Main Power Circuit.

Harmonic current reduction in a three-phase diode bridge rectifier

A novel method for reducing harmonic currents on the AC supply side of a three-phase bridge rectifier is presented. The principle of the method is to modify the current waveforms in the DC windings of the converter transformer by injecting a third harmonic current into the neutral point of the transformer. Passive LC filters connected between the rectifier output and the secondary neutral point act as third harmonic current sources. The effectiveness of the method is confirmed by laboratory recordings. >