Independent control of two permanent magnet synchronous motors fed by a four-leg inverter

Do Your Projects With Domain Experts…
Copyright © 2015 LeMeniz Infotech. All rights reserved
LeMeniz Infotech
36, 100 Feet Road, Natesan Nagar, Near Indira Gandhi Statue,
Pondicherry-605 005.
Call: 0413-4205444, +91 9566355386, 99625 88976.
Web : www.lemenizinfotech.com / www.ieeemaster.com
Mail : projects@lemenizinfotech.com
Independent Control of Two Permanent
Magnet Synchronous Motors Fed by a Four
Leg Inverter
Abstract
Introduction:
A V-connection inverter needs two capacitors to divide the
phase voltage of one inverter into two portions. A single inverter
can only drive one three-phase permanent-magnet synchronous
motor (PMSM). Therefore, two V-connection inverters are
necessary to drive two PMSMs independently. An alternate way
of independently driving two motors is using a four-leg inverter
(4LI). The independent speed control of induction motors fed by
the 4LI has been reported in. However, little or no work has
been reported on the independent control of two PMSMs using a
single 4LI. The independent speed and position control of two
PMSMs fed by the 4LI using vector control have several
challenges. First, the pulse width modulation (PWM) technique
used for a threephase voltage source inverter (VSI) is not
directly applicable for the 4LI because only two phases have to
be modulated for each inverter. Second, the characteristics of the
speed and position drive are unstable when the voltage at the
neutral point of the two capacitors deviates, resulting in

LeMeniz Infotech
Call: 0413-4205444, +91 9566355386, 99625 88976.
unbalance in capacitor voltages. In order to address these issues,
this paper presents an expanded two-arm modulation technique.
This technique only modulates two phases to obtain the three-
phase voltages required to control two motor drives. This paper
also proposes a method for achieving a balanced three-phase
current automatically using a vector control method.
Existing system:
The three phase voltage source inverter generates less
harmonic distortion in the output voltage utilized in the phase to
phase AC load. Also afford extra productive supply voltage
related to sinusoidal modulation technique. There are six
switching devices and only three of them are independent as the
operation of two power switches of the same leg are
complimentary. The combination of these three switching states
gives out eight possible space voltage vectors. The space vectors
forms a hexagon with 6 distinct sectors, each spanning 60
degrees in space. At any instant of time, the inverter can produce
only one space vector. In space vector PWM a set of three
vectors (two active and a zero) can be selected to synthesize the
desired voltage in each switching period.
Proposed system:
The 4LI consists of four switching legs and two split
capacitors connected in series. The inverter legs U1 and V1 are

LeMeniz Infotech
Call: 0413-4205444, +91 9566355386, 99625 88976.
connected to the U and V phases of PMSM1, and U2 and V2 are
connected to the U and V phases of PMSM2. The W phase of
both motors is shared in common and connected to the neutral
point of two split capacitors. vUNi, vVNi, and vWNi are the
phase voltages of the PMSMi (i = 1, 2). vki (k = U, V, W) is the
phase voltage of motor i. vwo indicates the neutral-point
potential of the two split capacitors. iUi, iV i, and iWi are phase
currents in the PMSMi, and iW is the inverter current in the
common connection to the midpoint of the dc-link capacitors. E
is the dc-bus voltage, and C is the capacitance of each of the dc
link capacitors. In this paper, to simplify the analysis, the
negative side of the dc bus is chosen as the reference point.
Applications:

LeMeniz Infotech
Call: 0413-4205444, +91 9566355386, 99625 88976.
 AC drives
Block diagram:
INPUT
DC supply
Split source
capacitor
4 leg
inverter
3 phase
load 1
3 phase
load 2

LeMeniz Infotech
Call: 0413-4205444, +91 9566355386, 99625 88976.
Tools and software used:
 MPLAB – microcontroller programming.
 ORCAD – circuit layout.
 MATLAB/Simulink – Simulation.

Independent control of two permanent magnet synchronous motors fed by a four-leg inverter

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (17)

Similar to Independent control of two permanent magnet synchronous motors fed by a four-leg inverter

Similar to Independent control of two permanent magnet synchronous motors fed by a four-leg inverter (20)

More from LeMeniz Infotech

More from LeMeniz Infotech (20)

Recently uploaded

Recently uploaded (20)

Independent control of two permanent magnet synchronous motors fed by a four-leg inverter