A 3'6kW Reversible Unity Power Factor Rectifier

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A 3.6kW Reversible Unity Power Factor Rectifier
Author Scott Reader Supervisor Dr
Geoffrey Walker
Problem Traditionally, the connection of power
electronic devices to the utility has led to the
distortion of the supply due to the nature of the
currents drawn by these devices. A distorted
voltage supply can cause a number of problems
including equipment failure and tripping. This
has become a significant problem in recent years
as the number of electronic devices has swelled.
In order to address the problem, a number of
standards have been introduced that place limits
on the harmonic levels injected into the utility.

Solution In order to comply with the standards, a
unity power factor input stage is required. For
this project, a full-bridge converter was used,
and the switching was controlled using
space-vectors. Using space vector
transformations, time-varying signals are
converted into a rotating reference frame in
which they appear as DC values. The signals are
also decomposed into their in phase and
quadrature phase components. Space vector theory
has been widely used to control three phase
motors. It is particularly useful for motor
control as it allows for independent control of
both the torque and speed of the motor. This
application can be adapted to rectification. The
ability to separately control both the direct and
quadrature components of the line current means
that the devices power factor can be actively
controlled. The hardware design utilised an
existing three-phase motor controller. After the
entire system had been tested in Matlab, control
software was written for a TMS320F2406 DSP.
Results