IPM is an interior Permanent magnet with self sensing and gets efficiency comparable to PMSM at much lower cost. Sensorless Vector control of IPM ensures better performance at low speeds, smoother operation, and position control possible.

1. copyright 2011 controltrix corp www. controltrix.com
www.controltrix.com
IPM motor drive

2. copyright 2011 controltrix corp www. controltrix.com
What is IPM?
• Interior permanent magnet motor
• Magnets are buried inside the rotor
• Permanent magnet synchronous motor
and switched reluctance motor together
• Reduces magnet size (rare earth
/expensive)
• Some portion comes from reluctance
torque

3. copyright 2011 controltrix corp www. controltrix.com
• Inductance varies with rotor position
• Allows self sensing (encoder less)
• Gets efficiency comparable to PMSM at much lower cost
What is IPM?.
Fig: Interior permanent
magnet motor

4. copyright 2011 controltrix corp www. controltrix.com
Sensor less Vector control of PMSM
• Required for best efficiency (meeting green norms etc)
• Complex math/DSP operations
• Only velocity control is possible
• Rotor position is required for vector control
• Sliding mode controller (SMC) estimates position (in absence of
encoder)

5. copyright 2011 controltrix corp www. controltrix.com
Sensor less Vector drive system diagram

6. copyright 2011 controltrix corp www. controltrix.com
• Low speed operation is not possible
• Field weakening allows operation beyond rated speed
• Field trading torque limit for speed
• Systematic analytical field weakening algorithms still required
Sensor less Vector control of PMSM.

7. copyright 2011 controltrix corp www. controltrix.com
Sensor less Vector control of PMSM control
block diagram

8. copyright 2011 controltrix corp www. controltrix.com
SL Vector Control of IPM (Mods.)
• More mathematically involved (trigonometric functions)
• Id and Iq references need to optimally generated
• Field weakening
• SMC may be modified for IPM but there are 2 more options

9. copyright 2011 controltrix corp www. controltrix.com
SL Vector Control of IPM (Mods.).
Option 1.
Better performance :
• Gopinath observer
• Lower speed (than SMC) performance is possible
• Smoother operation
• Calculable gains without trial and error

10. copyright 2011 controltrix corp www. controltrix.com
SL Vector Control of IPM (Mods.)..
Option 2.
Best performance :
• Self sensing technology
(using inductance variation dependence of position )
to sense rotor position + Kalman filtering
• Fixed point MIPS optimization required
• Near zero speed operation possible
• Position control is possible
• Nearly comparable to encoder based vector control servo drive

11. copyright 2011 controltrix corp www. controltrix.com
Summary
• Demonstrably Better performance
(efficiency, low speed performance, position control, system cost
and DSP capability demonstration)
• Next generation motor drives (compressors, air conditioning,
refrigeration)

12. copyright 2011 controltrix corp www. controltrix.com
How our expertise can help
• Proprietary algorithms allow 16 bit fixed point MIPs
optimized implementation of self sensing + Kalman filter
• Simulation and analysis
• Implementation on MCHV board or other custom hardware
• Performance Testing (test case generation and result analysis)
• Hardware design consulting
• Research and development

13. copyright 2011 controltrix corp www. controltrix.com
How our expertise can help
• Guaranteed Best possible performance and support
• Competitive prices
• Proto development using 3rd party EMS/EDS

14. copyright 2011 controltrix corp www. controltrix.com
Thank You
www.controltrix.com