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AC drives using PWM techniques

AC drives using PWM techniques content presentation: Power conversion unit, PWM generator, types of control, voltz/hertz, sensorless vector, field oriented control, sensorless field oriented control | @ Allen-Bradley Pulse Width Modulated PWM Drives AC Drives Using PWM Techniques @ Aften-Bradfey nortyiE J fUECTKrcr Rockwell Automation Bringing Together Leading Brand in Industrial Automation Pulse Width Modulated PWM Power Conversion Unit The block diagram below shows the power conversion unit in Pulse Width Modulated PWM drives. In this type of drive a diode bridge rectifier provides the intermediate DC circuit voltage. In the intermediate DC circuit the DC voltage is filtered in a LC low-pass filter. Output frequency and voltage is controlled electronically by controlling the width of the pulses of voltage to the motor. Essentially these techniques require switching the inverter power devices transistors or IGBTs on and off many times in order to generate the proper RMS voltage levels. Power Conversion Unit PWM Diode Bridge Intermediate DC Circuit Inverter Rectifier PWM Generator This switching scheme requires a more complex regulator than the Variable Voltage Input VVI . With the use of a microprocessor these complex regulator functions are effectively handled. Combining a triangle wave and a sine wave produces the output voltage waveform. PWM Pulse Width Modulated PWM The triangular signal is the carrier or switching frequency of the inverter. The modulation generator produces a sine wave signal that determines the width of the pulses and therefore the RMS voltage output of the inverter. PWM Output .