BENSHAW M2L 3000, User Manual

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4 – Theory of Operation
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4 - Theory of Operation
The Benshaw M2L 3000 family of medium voltage variable frequency motor drives features a unique power circuit, and a
state-of-the-art control platform, to provide the utmost in performance and application flexibility.
The M2L 3000 product family is forced-air cooled, and spans a power range from 300 hp to 6,200 hp, operating at industry
standard medium voltages up to 7200 VAC output. The drives can be used to control induction and wound field synchro-
nous motors.
This section provides an overview of the drive architecture, along with descriptions of major system components.
M2L 3000 Overview
The M2L 3000 variable frequency drive consists of two major system elements, shown in Figure 4; A Converter (Input
Power Stage) and an Inverter (Output Power Stage). The purpose of the Converter is to convert incoming voltage from the
AC mains into DC. The DC is passed to the Inverter using standard high-voltage shielded cable, where it is converted into
variable voltage, variable frequency 3-phase AC, then applied to the motor.
AC
Output
Inverter
Stage
DC
AC
Mains
Motor
Input
Power
Stage
Figure 4: Benshaw M2L 3000 Block Digrams
Most modern MV VFDs employ dual energy conversions (i.e. AC-to-DC and AC-to-DC), but are constrained to have these
constituent elements located in close physical proximity to each other, to avoid electrical complications that would compro-
mise the operation of the drive, and adversely affect reliability. The M2L 3000 is
not constrained in this manner. The Inverter
can be located adjacent to, or remotely from, the Converter without causing any adverse affects on the operation of the
drive. This feature imparts great application flexibility to users who may have space constraints, or choose to locate the heat
producing Converter away from environmentally conditioned equipment rooms or spaces.