Converter and DC Link

The converter section consists of a fixed diode bridge rectifier
which converts the three-phase power supply to a DC voltage.
The L1 choke and C1 capacitor(s) smooth the converted DC
voltage. The rectified DC value is approximately 1.35 times the
line-to-line value of the supply voltage. The rectified DC value is
approximately 650 VDC for a 480 VAC supply.

Pulse Width Modulation

Pulse width modulation (PWM) drives, like the Siemens
MICROMASTER and MASTERDRIVE VC, provide a more
sinusoidal current output to control frequency and voltage
supplied to an AC motor. PWM drives are more efficient and
typically provide higher levels of performance. A basic PWM
drive consists of a converter, DC link, control logic, and an
inverter.