Their power range is very wide, from milliwatts to megawatts. Rectifiers differ by the shape of dc signal, ripples, and efficiency that depends on rms, average, and amplitude values of voltage, current, and power. half-wave (1 pulse per supply period) and full-wave (2, 3, 6 pulses) rectifiers Rectifier data single-phase (M1, M2, B2) and three-phase (M3, B6) rectifiers The rectification processes are quite varied accordingly, there are different types of rectifying circuits Figure 1: AC/DC Converter Rectifier The systems built on diodes are called uncontrolled rectifiers, and those built on thyristors and transistors are known as controlled rectifiers because their dc output can be changed. 1 where the load is presented by the dc motors. The basic rectifier topologies are given in the circuit diagrams of Fig. For these purposes active rectifiers are developed. A special situation exists also with dc and ac loads, where the response of a line-commutated converter may be insufficient to cope with the stringent dynamic and energy efficiency demands and where an additional converter supplied by a dc link and operated with a high switching frequency is necessary. In low-power applications, vehicle, medicine, and household devices, where there is no ac supply or where reactive current and harmonics caused by a line commutation would be unreachable, it is accepted to employ forced commutatedconverters having a more complex circuitry and sometimes involving higher losses. To turn on a thyristor, an injection of a current pulse into its gate is required. the transfer of current from one conducting element to the next, as a function of the mains voltage. The term “line-commutated” describes the type of commutation, i.e. Thyristors are the main line-commutated power switches. This is due to simplicity of the circuits requiring a minimum number of active and passive components. Their speed of response is usually adequate to handle electromechanical transients occurring in motor drives and power suppliers.ĪC/DC line-commutated converters or, as they also called, converters with natural commutation or passive rectifiers, are the most usual choice for applications, where a single-phase and three-phase supply is available. Rectifiers are used as stand-alone units feeding single and multiple dc loads and as input stages of ac systems because of their virtually unlimited output power and fine controllability. They convert ac to dc in a number of industrial, domestic, agricultural, and other applications.
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