Induction Motor Emulation for Variable Frequency Drive Testing

Induction Motor Emulation for Variable Frequency Drive Testing

Induction Motor Emulation for Variable Frequency Drive Testing
Geoffrey Roy, Amber Reinwald, Matthew Geary
Advanced Power Electronics and Electric Drives Lab, Center for Clean Energy Engineering and Department of Electrical and Computer Engineering
University of Connecticut., Storrs, CT, USA


Prototype Completion

Motor to Transformer Relationship

The focus of this project was to design and construct an
induction motor emulator. The goal was to simulate an induction
motor under various loads in order to test variable frequency
drives (VFDs) for Lenze Americas. This was accomplished using
a 3kVA three-phase transformer and three balanced deltaconnected resistor banks to simulate the output power of an
induction motor. These resistors were controlled using
electromechanical relays activated by a graphical user interface
(GUI) designed in Labview.

To complete the prototype power resistors and a three-phase transformer
provided by Lenze were used. The Lenze VFD drove the transformer while the
output of the system was determined by a relay board and GUI. The corresponding
input and output powers were measured using the two watt-meter method.

From simulated and experimental data a relationship was created
relating a motors slip dependent rotor resistance to the emulating
transformers load resistance (Rv).

Prototype Research and Simulation
Before building a prototype, a simulation in MATLAB and
Simulink was built to prove the plausibility of the project. The idea
behind the prototype and simulation was that the equivalent
circuit of an induction motor and transformer are fundamentally
equal. The problem that needed to be solved was how to
incorporate a slip dependency in the transformers circuit. The slip
dependency was incorporated by including a variable load
resistance for the transformer. After running both simulations the
motor and transformer outputs were the same. All relevant
circuits and simulation diagrams are shown below.

Rr = a motors slip dependent rotor resistance
a = the turns ratio of the transformer
C = a motor constant to tune the exact load

Graphical User Interface (GUI)
Lenze VFD
drives the

Transformer output goes
to the relay board

Relay board activates
parallel resistor

Figure 5: Flowchart of the finished prototype with pictures of
the product

Output power
changes based on
varying resistance

A GUI was designed to select the relays that would activate or
deactivate the balanced delta-connected power resistors in order to
change the output power of the emulator. With the GUI a user can
emulate the rising torque of a motor torque vs. speed curve by using
the transient option however a user can also emulate the linear region
of the torque vs. speed curve using the single slip option.

Prototype Testing and Results
Table 1: Input and output powers for
both resistor banks

Figure 1: Three-phase induction Figure
equivalent transformer circuit diagram

Figure 6: 1.5 HP Torque vs. speed plot

Figure 8: Front panel of our graphical user interface

This induction motor emulator design eliminated moving parts
and is much lighter than actual induction motors. Thus saving space
and energy while simultaneously providing the correct input and
output powers of an induction motor. Ultimately providing Lenze with
a safer, more efficient method of testing variable frequency drives.

Figure 3: Induction machine simulation diagram


Figure 4: Emulation transformer simulation block diagram
Copyright 2015 Advanced Power Electronics & Electric Drives Lab (APEDL)

Figure 7: 1.5 HP Output power plot

We are extremely thankful for the help and guidance of our project manager Chris
Johnson and all those from Lenze who mentored us; Mark Collins and Neil Pande as
well as UConn Professor Ali Bazzi and UConn graduate students Yiqi Liu (Ph.D.) and
Artur Ulatowski (M.S.).

Recently Viewed Presentations

  • Human Computer Interaction - UMIACS

    Human Computer Interaction - UMIACS

    Mental models exist at many levels Hardware, operating system, and network Application programs Information resources Input Devices Text Keyboard, optical character recognition Speech recognition, handwriting recognition Direct manipulation 2-D: mouse, trackball, touch pad, touch panel 3-D: wand, data glove Remote...
  • 6.3 Integration by Parts -

    6.3 Integration by Parts -

    6.3 Integration by Parts Special Thanks to Nate Ngo '06 First, start with the Product Rule for differentiation. Integrate both sides of the equation to obtain: Simplify, and by manipulating the equation we get…
  • SPRING FINANCE WORKSHOP At the WASBO Accounting Conference

    SPRING FINANCE WORKSHOP At the WASBO Accounting Conference

    DPI is required to review the pupil's IEP and determine the scholarship amount, based on formula established in the proposal (lesser of "state average" by formula, or "actual cost" to the school as with existing choice program).
  • Business Management, 13e CHAPTER 3 The Manager as

    Business Management, 13e CHAPTER 3 The Manager as

    Leaders have excellence Human Relations skills . Developing as a leader. CHAPTER 3. Checkpoint . Why do leaders need human relation skills? Leaders must take responsibility for the work of the group they lead, so they need to demonstrate and...
  • The Physical Regions of Canada

    The Physical Regions of Canada

    The Arctic region includes plains, lowlands, and mountains. ... The Rocky and Coastal mountains are the youngest landforms in Canada. Formed when plate collision caused the earth's crust to buckle, pushing and folding volcanic rock into mountains.
  • Extended History of Africa

    Extended History of Africa

    Swahili Civilization. Set of commercial city-states stretching all along the East African coast. Grew due to participation in Indian Ocean trade. Clan chiefs became kings. An African merchant class developed. Urban with cities of 15,000-18,000 people. Each Swahili city was...


    WHAT DO WE DO? WE WORK WITH BRANDS LIKE A, B AND C. We create amazing digital products like x, y and z. (NB. This is your space to tell people who you are, see notes below)
  • Preseparation Counseling Checklist

    Preseparation Counseling Checklist

    Provides training and education opportunities to meet the needs of businesses looking for skilledworkers. ... Completed a job application package (resume, personal/professional references and, if required, application) ... MARGARET-MARY A NF-03 USAF AFSPC 21 FSS/FSK ...