GE Industrial Solutions AF-600 FP High Power Unit Sizes 6x - Manual (Page 67)

5.3.2 Sources of EMI
Modern frequency converters (see illustration below) utilise Insulated-Gate Bipolar Transistors (IGBTs) to provide an efficient and cost effective means to create
the Pulse Width Modulated (PWM) output waveform necessary for accurate motor control. These devices rapidly switch the fixed DC bus voltage creating a variable
frequency, variable voltage PWM waveform. This high rate of voltage change [dV/dt] is the primary source of the frequency converter generated EMI.
The high rate of voltage change caused by the IGBT switching creates high frequency EMI.
130BX137.10
AC Line
Rectifier DC Bus Inverter
Motor
Filter reactor
IGBT
Filter capacitor
PWM waveform Sine wave
Illustration 5.1: Frequency Converter Functionality Diagram
High Power Service Manual for Unit Sizes 6x
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