Inverter and programmable controls in heat pump
applications
Biagio Lamanna
Application Competence Centre Manager
Product Development Process
CAREL INDUSTRIES Srl
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
Summary
Why BLDC inverter compressors?
•  Compressor motor technologies
•  Partial load and seasonal efficiency
Carel pCOsistema+ for HP application
•  Ready to use solution approved by the compressor manufacturers
•  Full customizable hardware and software
Features & Benefits of an integrated solution
VS a stand alone inverter
Conclusions
(for CAREL algorithm details see the end of the presentation)
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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What does BLDC means?
BLDC (brushless direct current) motor
BPM (brushless permanent magnet) motor
DC (direct current) inverter
IPM (interior permanent magnet) motor
SPM (surface permanent magnet) motor
EC (electronic controlled) motor
Different NAMES for the
SAME technology
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Why BLDC inverter compressors?
Electric motor evolution:
• AC asynchronous induction motor
 Both compatible with standard on-off technology and inverter use
 Good performances only for motors developed specifically for inverter use
 Energy waste due to the need to create the rotor magnetic field
• DC brushless motor (SPM)
 The rotor is a permanent magnet, there no energy waste
 The magnets of SPM motors need to be fixed on the rotor surface using adhesive,
high speed is not allowed
• DC brushless motor (IPM)
 The magnets of SPM motors are inside the rotor
 Highest efficiency and performances
 High speed
 Requires a top level BLDC inverter
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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The motor structures of the IM (induction motor), SPM (Surface permanent
magnets, IPM (Interior permanent magnets)
Comparison table of IM, SPM and IPM motors
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Why BLDC inverter compressors?
The efficiency improvement of the brushless motor technology versus
the induction motor can be estimated on 4-5%
Confidential
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Speed controlled BLDC compressors
Scroll or twin rotary, up to 35kW cooling capacity, mainly R410a
refrigerant, up to 65°C cond. temperature with no liquid injection
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Why BLDC inverter compressors?
New unit testing and
rating procedures
based on partial load
and seasonal efficiency
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Why BLDC inverter compressors?
Variable speed compressors can
match the partial load giving an
extremely high unit efficiency due to…
…the improved efficiency of the
compressor at partial load as motor
performance and basic COP…
Pressure
Increased
efficiency
… together with improved efficiency of
both heat exchangers
Enthalpy
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Speed controlled BLDC compressors
Unit performances with BLDC compressors
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Speed controlled BLDC compressors
Unit performances with BLDC compressors
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3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Makes DC inverter technology available
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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pCOsistema+: off the shelf technology
Thanks to the experiences of
CAREL Labs
1tool library provides a wide
range of turn key solutions
to make DC inverter
technology available to heat
pump manufacturers.
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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pCOsistema+: off the shelf technology
Development time for
BLDC inverter compressor
management:
8 months
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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pCOsistema+: off the shelf technology
Development time for EEV
management:
3 months
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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pCOsistema+: off the shelf technology
Development time for
brushless sensorless
technology drive:
12 months
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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pCOsistema+: off the shelf technology
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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pCOsistema+: user interfaces range for deep
customization
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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pCOsistema+: wide range of programmable controllers
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Complete HP control
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Saving more than 40 development weeks
Makes DC inverter technology available
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Features & Benefits of an integrated solution
ime:
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Features & Benefits of an integrated solution
Compressor safeguard
Managed function
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ra fe
Compressor start up procedure
Compressor working envelope
Compressor timings
Compressor minimum pressure drop
Suction superheat
Discharge superheat
Discharge gas temperature
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Features & Benefits of an integrated solution
Unit safeguard and performance
Managed function
s
Ext
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t
a
ra fe
Compressor start failure management
Compressor equalization at start-up
Drive alarm management
Speed regulation according to the
application needs
Drive parameter pre-set for different
compressors
Drive custom parameters load and
save management
Drive complete user interface
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Conclusions
Conclusions
A BLDC inverter compressor unit:
• Has the top level compressor motor technology
• Meets all present and future efficiency rating specifications
• Grants high performances due to the wide range of cooling
capacity modulation that allows the best application
temperature control
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Conclusions
Conclusions
A full integrated system for HP application:
• Meets ALL compressor manufacturer specifications (with their
official approval!)
• Allows to use the compressor in the full speed range in all the
working envelope conditions
• Avoids the unit OEM to spend months of R&D development
• Grants a full control on the unit with plenty of extra features
compared with a stand alone inverter drive that allow to reach
the best performance level
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Conclusions
Conclusions
A full customizable system for HP application:
• Meets all unit manufacturer needs in terms of performance/cost
compromise
• Allows the unit manufacturers to keep their knowledge about the
application and customize any part of the software and user
interface
• Has many user interface solutions for each different user profile
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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Inverter and programmable controls in heat pump
applications
THANK YOU FOR YOUR KIND
ATTENTION
Biagio Lamanna
Application Competence Centre Manager
Product Development Process
CAREL INDUSTRIES Srl
biagio.lamanna@carel.com
+390499716611
www.carel.com
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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CAREL control algorithm details
Compressor working envelope:
•  Min/Max compressor ratio
•  Min pressure differential
•  Max motor current
•  Max/min discharge pressure
•  Max/min suction pressure
•  Max discharge temperature
(different for each zone)
•  Min/Max compressor speed
(different for each zone)
•  Different management for
each compressor!
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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CAREL control algorithm details
Compressor working envelope management:
  Unit capacity reduction by EEV control in case
of low compressor ratio, high suction
pressure, high motor current, etc…
  Compressor capacity reduction in case of high
discharge pressure and/or temperature, low
suction pressure, etc…
  Drive acceleration/deceleration ramp control
to avoid going out from the safety working
areas
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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CAREL control algorithm details
Compressor windings temperature management:
By means of measuring:
•
compressor shell temperature
•
compressor discharge gas temperature and superheat
•
compressor motor current
The control system can:

stop the compressor due to high shell temperatures
even if…

… the drive can manage the compressor speed in
case of high motor current without stopping it and…

… both EEV and compressor control modules can
regulate the discharge superheat or temperature for
optimal compressor performance with maximum
compressor speed by means of the safety liquid
injection
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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CAREL control algorithm details
Unit start-up management:
The synchronization between compressor, drive
and EEV management allows the take care of:
  Pressure differential before start
  Equalization, if needed or…
  … compressor start-up even with up to 10barg
pressure difference.
  Pressure differential after start ( greater than the
minimum allowed)
  Oil recovery after start
  Compressor warm up
  Compressor timings (minimum ON time, minimum
OFF time, minimum time between different starts)
  Start-up quick retry in case of start failure
  Wrong wiring, blocked rotor, damaged motor
windings, or any start-up problem.
3rd EHPA European Heat Pump Forum | Brussels | 20.05.2010
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CAREL control algorithm details
Compressor alarm management:
Centralized alarm management for all unit
components:
•  The unit can work even with broken probes
•  Critical alarms manual reset by user interface or remote
monitoring system
•  Automatic to manual alarm reset after a defined number
of attempts
•  All alarms in the same UI:
  Unit alarms (i.e. low temperature, low water flow,
high pressure, etc)
  Compressor alarms (i.e. high discharge temperature,
out of envelope, low compressor ratio, etc.)
  Drive and motor alarms (i.e. high motor current, low
supply voltage, communication offline, etc.)
  Valve alarms (i.e. stepper motor damaged, low
suction superheat, etc.)
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