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The two-level converter is the simplest type of three-phase voltage-source converter [29] and can be thought of as a six pulse bridge in which the thyristors have been replaced by IGBTs with inverse-parallel diodes, and the DC smoothing reactors have been replaced by DC smoothing capacitors. Such converters derive their name from the fact that ...
At 12 pulse converter stations, only harmonic voltages or currents of the order 12n + 1 and 12n - 1 (on the AC side) or 12n (on the DC side) result. Filters are tuned to the expected harmonic frequencies and consist of series combinations of capacitors and inductors.
Rectifier circuits are often classified by the number of current pulses that flow to the DC side of the rectifier per cycle of AC input voltage. A single-phase half-wave rectifier is a one-pulse circuit and a single-phase full-wave rectifier is a two-pulse circuit. A three-phase half-wave rectifier is a three-pulse circuit and a three-phase ...
The average output voltage is directly proportional to the ON time of chopper. The ratio of ON time to total time is defined as duty cycle. It can be varied between 0 and 1 or between 0 and 100%. Pulse-width modulation (PWM), or pulse-duration modulation (PDM), is a technique used to encode a message into a pulsing signal.
One six-pulse bridge consists of the even-numbered thyristors, the other is the odd-numbered set. Although better than single-phase rectifiers or three-phase half-wave rectifiers, six-pulse rectifier circuits still produce considerable harmonic distortion on both the AC and DC connections.
Long distance HVDC lines carrying hydroelectricity from Canada's Nelson River to this converter station where it is converted to AC for use in southern Manitoba's grid. A high-voltage direct current (HVDC) electric power transmission system uses direct current (DC) for electric power transmission, in contrast with the more common alternating current (AC) transmission systems. [1]
A blocking oscillator (sometimes called a pulse oscillator) is a simple configuration of discrete electronic components which can produce a free-running signal, requiring only a resistor, a transformer, and one amplifying element such as a transistor or vacuum tube.
Pulse-width modulation (PWM), also known as pulse-duration modulation (PDM) or pulse-length modulation (PLM), [1] is any method of representing a signal as a rectangular wave with a varying duty cycle (and for some methods also a varying period). PWM is useful for controlling the average power or amplitude delivered by an electrical signal.