Results of an Innovative 100kW Induction Heater Prototype Testing

Bernard Paya, Jean-Marie Fourmigue, Electricité de France

Baskar Vairamohan, Ammi Amarnath, Electric Power Research Institute

ABSTRACT

Industrial induction heating processes can contribute to the European Union (EU) energy
saving goal of 20 percent before 2020. Induction manufacturers already propose many efficient
solutions available at industrial scale. To improve induction devices for better energy efficiency,
EDF R&D set up a French collaborative project called Innovative Solutions for Induction
Systems (ISIS) with the financial support of the French National Research Agency (ANR).
The objective of ISIS is to promote induction heating as a best available technology
(BAT) and to develop innovative solutions to increase its efficiency. This paper reports the ISIS
project innovations. The paper also discusses about the efficient heat conversion from the
induction heating devices through the use of new auto-adaptive multi-coil power supply with low
losses coils. An important aspect of this project is the recovery of fatally lost heat energy
(cooling of the inductors).
During the prototype testing, first the control algorithms of the multi-coil technology
were successfully tested on a 100 kW 3-coils power supply. A homogenization technique is
proposed to model a multi-strand coil and to use it in industrial setting. The multi-strand coils are
now used only in low power residential applications such as induction cooking. A heat recovery
test bench is built and equipped with a predictable function control (PFC) loop to fit with the
production fluctuations. This paper also presents an analysis of the U.S. potential market for
these new induction heating approaches and their applications in industries.

Induction Heating: Background

Induction heating is a method of providing fast and consistent heat for manufacturing
applications that involve bonding or changing the properties of metals or other electrically-
conductive materials. Induction heating may be used to replace a wide variety of conventional
process heating methods, such as fossil/electric furnace heating, salt/lead bath heating, flame
heating, and a variety of specialized brazing processes. All of these processes heat the outer
surface of the workpiece. In contrast, induction heating heats deep inside the workpiece.
The induction heating process relies on induced electrical currents within the material to
produce heat. The electromagnetic field is produced by applying current with a frequency of 60
Hz to 800 kHz to an inductor coil in proximity to the workpiece. Where the magnetic field
intersects a workpiece made from any electrically conducting material, it generates a circulating
current, which generates heat. The lower the frequency, the deeper the current penetrates into the
workpiece. The basic components of an induction heating system are an AC power supply,
induction coil, the workpiece (material to be heated or treated), and the cooling system.
Industrial induction heating power supplies cover a wide size range from approximately 1
to 3,000 kW of electric power. The size of the power supply depends on several variables,
including the workpiece mass, the required temperature elevation, the specific heat and electrical
properties of the workpiece, and the coupling efficiency of the coil design. In addition, thermal
losses due to conduction, convection, and radiation must also be considered.

©2013 ACEEE Summer Study on Energy Efficiency in Industry 3-1

 The
T AC pow wer supplies utilize insu ulated-gate bbipolar transsistor (IGBT
T) or metal ooxide
semicond ductor field--effect transiistor (MOSF FET) technoologies. Advvances in tecchnology include
the use of multiple microproceessors, rapid d tuning, addvanced conntrols, and an intuitive user
interface. Depending g upon the process
p and the
t workpiecce, the poweer supply prrovides curreent to
the coil only when heath is need
ded. Contrasst that to baatch ovens thhat operate continuouslly for
hours at a time and heat
h more thaan just the workpiece.
w
The
T coil desig gns are careefully tailored for each wworkpiece. FFigure 1 show ws a circulaar coil
design being used fo or inductionn hardening (EPRI 20077). In a sensse, coil desiign for induuction
heating is
i built upon n a large stoore of empirrical data wwhose develoopment sprinngs from seeveral
simple in
nductor geom metries such as solenoid,, helical, panncake, and chhannel coilss. Because off this,
coil desig
gn is generallly based on experience.

Figure
F 1. Co
opper Brazing of High--Pressure Stteel Fitting U
Using Induction Heatin
ng—
an Applica
ation That Iss Often Don
ne in a Batcch Oven

The
T inductor is similar to o a transformmer primaryy, and the w workpiece is equivalent tto the
transform
mer secondarry. Thereforre, several off the charactteristics of trransformers are useful iin the
developm ment of guid delines for co oil design. One
O of the m most importan ant features oof transform
mers is
the fact that the effiiciency of coupling
c bettween the w windings is iinversely proportional tto the
square off the distancce between them.
t In adddition, the cuurrent in thee primary off the transformer,
multiplieed by the num mber of prim mary turns, is equal to thhe current in the secondaary, multiplieed by
the numb ber of second dary turns.
Coil
C designs are based on the heating-patternn requiremeents of the applicationn, the
frequency y, and the power-densit
p ty requiremeents. In addittion, the maaterial-handliing techniquues to
be used for
f productio on determinee, to a large extent, the ccoil to be ussed. If a partt is to be insserted
in a coil, moved on a conveyor, or o pushed en nd to end, orr if the coil/hheat station ccombinationn is to
move on nto the partt, the coil design
d mustt take the aappropriate handling reequirementss into
consideraation. Acco ordingly, a variety of specialty c oil designs have evolvved for speecific
applicatioons.
Because
B of itss low resistiv
vity, fully an
nnealed, highh-conductivity copper iss most comm monly
used in thhe fabricatio
on of inductiion heating coils.
c The coopper is typiically in a tuubular form,, with
a minimu um outer diaameter of 0.125 inch (0.32 cm) to aallow for waater cooling. Material oof this
kind is avvailable in a wide range of cross sections (roundd, square, andd rectangulaar) and sizes..
Cooling
C is normally req quired for th he AC poweer supply annd the coilss to removee heat
generatedd by the eq quipment. Due to the close proxim mity to the hhot workpieece, the coills are

3-2 ©2013 ACEEE Summer Study on Energy Efficiency in Industry

 manufactured from hollow tubes, and cooling water is circulated through the coils. The type of
cooling equipment depends on the induction heating power level, the surrounding environment,
and the temperature of the waste heat. The cooling equipment choices are water-to-air heat
exchangers, water-to-water heat exchangers, and chillers.
Table 1 shows as example a typical power distribution in the case of a billet heating up to
1,200 °C (2,192 °F) using a 500 Hz thyristor inverter. Losses can be divided into two main
categories: the electrical losses and the thermal losses. The column “Where” indicates in which
cooling circuit the losses are collected. The two right columns give solutions to improve
efficiency and their corresponding drawbacks. Solutions written in italics are the innovative
solutions developed in the frame of ISIS project described below.

Table 1. Typical Power Distribution. Billet Heating up to 1,200oC, 500Hz Inverter

How
Origin Where How to improve Drawback
much
Resonant inverter
Inverter Inverter cooling
7% Low temperature
losses circuit Heat recovery
requested
Electrical losses

Thermal insulation
Air-gap reduction
reduced
Multi-layer or multi- Cooling difficulties
Coil cooling
Coil losses 19 % strand configuration More expensive
circuit
Adaptation to
Magnetic interaction
workpiece size (multi-
between coils
coil)
Workpiece Thermal insulation Electrical efficiency
Coil cooling
radiative 4% increase reduced
Thermal

circuit
losses

losses Heat recovery Safety degraded

Workpiece Mechanical
conductive 6% support cooling Heat recovery Safety degraded
losses circuit
Useful
64 % Billet
energy

In this paper an innovative auto-adaptive control strategy is discussed along with a

prototype development and implementation at EDF laboratories. The prototype is a 100 kW 3-
coil induction heater with auto-adaptive control algorithm. Expanding the coil structure to be a
multi-stranded construction as opposed to the traditional single solid coil is also explained with
successful test results. Finally the wasted heat recovery of this induction heating system that is
currently in operation at EDF laboratory is explained in detail.

Innovative Solution for Induction Systems (ISIS)

EDF R&D is a key-player in the development of induction heating in France and in
Europe for several decades and is working on energy saving solutions using induction (Paya,
Pateau & Neau 2010). It set up a French project called ISIS (Innovative Solution for Induction
Systems) together with French academic partners – SIMAP (Grenoble), LAPLACE (Toulouse),

©2013 ACEEE Summer Study on Energy Efficiency in Industry 3-3

 ARMINES (Paris) and CRISMAT (Caen) – and industrial partners – FIVES CELES (Mulhouse)
and ATYS CONSULTANTS (Grenoble) – and supported by French Research National Agency
(ANR).
Its primary objective is to favor the induction penetration in industrial sectors where it
could be especially efficient. For that purpose, work was approached from three complementary
points of view:

 The techno-economical research of induction heating penetration potentialities (EDF,

ATYS). This analysis aims to identify processes where induction solution turns out
relevant regarding energy efficiency. In particular it looks for implementation
possibilities of ISIS innovative solutions.
 The improvement of electroheat conversion of induction heating devices. On the
converter side, the project implements a flexible multi-coil supply, adapting itself to a
wide variety of heated parts (LAPLACE, CELES, and EDF). On the inductor side, it
develops multi-strand conductors with better energy performance than conventional coils
(SIMAP, CELES, and EDF).
 The recovering of the fatally lost heat energy and its reuse, preferably in the process line
(ARMINES, ATYS). This energy comes either from inductor cooling circuits (low or
medium temperature energy) (EDF) or from already treated hot parts (high temperature
energy) (CRISMAT, LAPLACE). The various temperature levels lead to different
recovery strategies.

This project begun in December 2009 will last almost four years and aims to reach the
industrial prototype level of the innovations.

Project Description

The scientific program is organized in five main tasks, each other independent, involving
at least two or three partners and lasting the all duration of the project.
The first task “analysis of induction potential diffusion” aims to identify processes for
which an induction solution may be relevant in term of energy efficiency. Diffusion of
innovative solutions developed in the other project tasks is also analyzed.
The next two tasks study technical developments of induction heating solution regarding
the improvement of energy consumption. In that way, the task “realization of an auto-adaptive
multi-coils power supply” aims to design a flexible power supply able to energize many coils in
mutual interaction and driving the coils’ current to adapt the heater to a large range of heated
pieces. Preliminary works were done before, both on the inverter technology (Manot 2013;
Souley et al. 2009; Souley et al. 2010 a) and on a multi-coil configuration (Forzan et al. 2010).
The aim of this task is to reach a semi-industrial scale. The task “development of low losses
inductors” develops multi-strands solutions having better performance than conventional coils.
This work aims to extend the relevance of the CELINE™ concept to higher frequency range (up
to 400 kHz).
The last two tasks deal with heat recovery on and around induction process. The task
“heat recovery on induction heating losses” studies the pieces of equipment to be added on
existing cooling systems to recover the fatal coil losses. Preliminary studies (Paya 2008; Paya,
Gheorghe & Tudorache 2009) show that it is possible to use high fluid temperature (above 90

3-4 ©2013 ACEEE Summer Study on Energy Efficiency in Industry

 °C) withhout damagin ng the enerrgy efficienccy. The taskk “heat recoovery on alrready treatedd hot
parts” aim
ms to recyclle the energyy collected by
b the piecee during its hheat treatmeent for otherr uses
such as semi-produc
s ct preheating
g before indu uction heatinng. This maay be particuularly relevaant on
induction
n heating lin
nes due to hiigh parts tem
mperature at the end of tthe line (typically 600 too 800
°C).

Laboratory Testing
g: Descriptio
on and Resu
ults

Auto-adaptive multti-coil powerr supply pro ototype des cription. Too control thee current injeected,
each coill is energizeed by a speccific inverterr. All the inv
nverters workk at the sam me frequencyy, but
current amplitude
a annd phase may y vary. The control of th
the multi-coiil system is organized inn two
interlinkeed loops (seee Figure 2).
T outer loop controls the temperrature profille and deterrmines the rreference cuurrent
The
value forr each coil. The
T inner loo op controls th
he current innjected in eaach coil by comparison wwith a
referencee value giveen by the ou uter loop. To
T achieve thhat, a full eelectromagneetic, thermaal and
power eleectronic mod deling was developed
d by
y LAPLACE E (Souley et al.2010 b).

Figure 2. Scchematics and

a Strategyy of the Multi-coil Control

The
T current control
c requ
uires the kno owledge of the impedaance matrix of the multti-coil
system thhat can be evvaluated eith
her by measu urement or bby a 2D or 3D electromaagnetic numeerical
model. This
T impedaance matrix is introduceed into the ppower electtronic model which givves in
return th
he driving seequences off switches or o gate contrrol signals. These sequuences have been
successfuully implemeented into a 100 kW ind duction heateer. Figure 3 shows the ppicture of thee 100
kW 3 coil power sup pply prototyype built and d operationaal at the EDFF laboratoryy that implemments
the auto-adaptive mu ulti-coil conttrol strategy.

©2013 ACEEE Summer Study on Energy Efficiency in Industry 3-5

 Figure 3. Model of Multi-coil Power Supply and Inductors with Three Associated
Coils

Figure 4 shows the experimental results of the auto-adaptive multi-coil control power
supply testing. The x-axis represents the time in milli-seconds while the y-axis represents the
magnitude of current going through each coil. The source current, phase – 1 and phase – 3
current magnitudes are shown in Figure 4. Key highlight of the waveforms shown in Figure 4 is
that the current magnitude in each of the pairs of phases are varied to meet the specific heat
requirements of the object to be heated which is not obtained in traditional control strategies.
The temperature control requires the knowledge of the normalized induced currents
generated by each coil separately and evaluated by a 2D or 3D electromagnetic model; the global
induced current distribution is then determined by superimposition of the elementary induced
current’s distribution. The thermal problem is modeled directly inside the power electronic
model and gives in return the values of the reference currents to be put into each coil. The
temperature control loop has been already tested numerically.
Experimental validation in a large setting is in progress since January 2013 on a 600 kW
facility implemented at Fives Celes premises. For that purpose, Fives Celes has developed a new
driving card able to control the inverter bridges. Numerical capacities (memory, fast
calculations) have been increased to host the control loops software. Each slave card dedicated to
an inverter hosts the corresponding current loop and the master card hosts the temperature loop.
Fast communication busses at basket bottom allow data transfer between the cards.

3-6 ©2013 ACEEE Summer Study on Energy Efficiency in Industry

 Fig
gure 4. Exp
perimental Result
R of thee Multi-coill Current Control
(Source Current
C (Blu
ue), Phase 1 (Green), PPhase 3 (Red d))

Low losses multi-sttrand coils.. The multi--strand conffiguration off coil conduuctor, comm monly
called Liitz wire, is widely used d in small power
p devicces such as domestic innduction coooking
systems.
Itts extrapolatiion to high power
p industtrial applicattions requirees paying atttention to thee coil
cooling. Thus, it is neecessary to have
h a good evaluation oof the Joule losses in thee windings. F Finite
elements numerical models
m quicckly reach thheir limits iff several thoousands of sstrands are ffinely
meshed.
First simulatiions were realized by SIIMAP with a small num mber of strannds. 2D moddeling
(see Figuure 5 and Fiigure 6) sho ows a curren nt distributioon among thhe conductoors looking llike a
global sk
kin effect. Inn the Figures 5 and 6 th he colors corrrespond to the temperaature of the coils,
blue reprresenting colld and red reepresenting hot.
h

©2013 ACEEE Summer Study on Energy Efficiency in Industry 3-7

 Figure 5. Joule Losses in the Multi-strands Wire – 49 Strands Wire

Figure 6. Joule Losses in the Multi-strands Wire – 126 Strands Wire

To evaluate the global Joule losses in the composite wire, SIMAP has proposed a
homogenization technique (Scapolan, Gagnoud & Du Terrail 2012) the multi-stands coil is
approximated by an equivalent electrical resistivity applied to the global cross section of the
wire. Simulations of an aluminum bar heating with a homogeneous model and with the fine
multi-strand coil models are in agreement in a wide frequency range (see Figure 7). The
significant conclusion drawn from this simulation as see in Figure 7 is that the multi-stranded
coils can be approximated to a solid metal coil with equal cross section area.

3-8 ©2013 ACEEE Summer Study on Energy Efficiency in Industry

 Figure 7. Comparison between the Homogeneous Model and the Multi-coil on Joule
Losses in the Coil and the Load

Heat recovery. A heat energy recovering system using heat exchangers is in operation in EDF
laboratory since 2010.
The main goal of the heat recovery test bench is to test and quantify in industrial
conditions the heat energy to be recovered coming from the coil cooling circuit. Figure 8 shows
the schematics of the test bench and provide the main functions of the bench. The test bench is
made up of two heat exchangers which can be by-passed according to the control and regulation
system. The “recovery heat exchanger” collects the heat to be recovered and transfers it to the
reuse, the recovery circuit simulator. For our test bench, this simulator is a 300 liters (79 liquid
gallons) water tank (“domestic hot water storage”) which can store the collected energy.

Figure 8. Heat Recovery System Schematics at EDF

70°C
75°C

RECOVERY
DOMESTIC HOT CIRCUIT
WATER CIRCUIT
25°C 30°C

20°C

DOMESTIC HOT
WATER STORAGE

50°C
INDUCTOR
CIRCUIT

50°C 52°C IN DUCTOR

80°C
16°C

75°C

19°C 30°C

WASTE HEAT RECOVERY HEAT Two-way co ntrol va lve

EXCHAN GER EXCH ANGER

INDUSTRIAL Three-way contr ol va lve

SEWER
WATER

The “waste heat exchanger” evacuates the remained energy to ensure a safe use of the
induction heating device. These two exchangers are designed for 100 kW. The water flow is
obtained by two pumps and their associated valve, the smallest for the range 0.3 – 2 cubic meters
per hour or m3/h (equal to 1.32 – 8.81 gallons per minute or gpm) and the biggest for 1.5 – 9

©2013 ACEEE Summer Study on Energy Efficiency in Industry 3-9

 m3/h (equal to 6.61-39.6 gpm) water flow rate. Many temperature and flow-meter sensors are
implemented in different locations to evaluate the energy balance or for driving the test bench.
A “Predictable Function Control” (PFC) regulation has been implemented to drive the
bench. This system is more efficient compared to a conventional PID controller. Because of the
precise modeling of the bench parts and the induction device, it is possible to anticipate
disturbances (such as induction power fluctuations) and adapt the heat recovery in order to
always work in a safe way. As an example, we have simulated the load curve of a melting
workshop. During the melting process, the crucible works at full power during the melting phase,
at reduced power during the elaboration or temperature holding phases and is switched off during
loading and casting phases.

Induction Heating: Applications and Market Study

Electric induction heating and melting can increase productivity and reduce energy use,
depending on the baseline technology it replaces. Likewise, the simple payback period for this
technology will vary according to the technology replaced, but it can be as short as one year
when used instead of equipment such as fossil-fuel batch ovens. Applications of induction
heating and melting have enabled energy cost savings of 20–30% by users, per examples cited
below, and productivity has increased in example applications as well.
There are many applications of induction heating, which includes but not limited to the
following:

 Brazing, bonding, soldering, and welding

 Curing of coatings
 Electromagnetic stirring and casting
 General purpose heating and preheating
 Heat treating (includes hardening, annealing, tempering, and stress relieving)
 Heating of non-conductive materials using a conductive susceptor (usually a metal
interface)
 Levitation melting
 Melting
 Shrink fitting and press fitting

A new application of induction heating is a non-contact system for the heating barrels
used with plastics molding and extrusion machines developed by Xaloy, Inc. (EPRI 2007). They
have demonstrated that induction barrel heating with an interposed insulating layer increases
barrel heating efficiency to around 95% from typically 40 to 60% with band-heaters. By virtually
eliminating the thermal mass of the heating system, induction accelerates temperature response
to seconds (versus minutes with band-heaters), which greatly improves control predictability and
reduces the sensitivity of control performance to thermocouple depth. In addition, induction
heaters are more reliable than band heaters, and can typically provide three times the heat flow
into the barrel.
Depending upon the size and application, the capital cost of the induction heating systems
can range from under $8,000 to over $1 million. The smallest systems generally cost around
$8,000/kW while the largest systems are perhaps $1,000/kW (EPRI 2007). Maintenance costs
are usually lower than the alternatives due to the reliability of solid-state electronics and minimal

3-10 ©2013 ACEEE Summer Study on Energy Efficiency in Industry

 moving parts. The potential payback when replacing batch ovens burning fossil fuels is often
about a year.
Ameritherm, Inc. was the first North American manufacturer to introduce all solid-state
induction heating RF power supply technology in 1986. At least a dozen vendors now offer
solid-state induction heating equipment for a wide variety of applications as shown in Table 2.
Equipment specifically tailored to new applications is continuously under development.

Table 2. Partial List of Induction Heating Manufacturers in USA

Manufacturer Description
Ajax Tocco 1745 Overland Avenue Ajax Tocco designs and manufactures induction
Magnethermic© Warren, OH 44482 heating and melting equipment for various industries
Corporation 800.547.1527 and applications. The equipment includes induction
www.ajaxtocco.com coils, ovens, and power supplies.
©
Ameritherm 39 Main Street Ameritherm© manufactures micro-processor based RF
Scottsville, NY 14546 induction heating equipment. Ameritherm© offers free
585.889.9000 evaluation of customer parts to allow a precise
www.ameritherm.com recommendation of the proper induction heating
system for the applications.
Eldec Induction 3355 Bald Mountain Rd., Unit 30 Eldec manufactures systems for induction heating
U.S.A. Auburn Hills, MI 48326 used in various applications including hardening,
248.364.4750 brazing, annealing and tempering, shrink joining as
www.eldec-usa.com well as removal, and many other areas.

Induction 35 Industrial Park Circle Induction Atmospheres designs and builds turnkey
Atmospheres Rochester, NY 14624 induction heating solutions for continuous flow
LLC 585.368.2120 manufacturing. They evaluate customer parts and
www.inductionatmospheres.com process requirements in their laboratory to determine
the optimum induction heating system that matches
the process requirements.
Induction 209 Travis Lane Induction Systems offers the latest technology in heat
Systems, Inc. Waukesha, WI 53189 treating scanners, power supplies, billet heating,
888.856.2096 custom heat treating systems, water systems, and
www.inductionsystemsinc.com quality monitor systems, as well as servicing all types
and makes of induction equipment.
Inductoheat, Inc. 32251 North Avis Dr. Inductoheat builds induction heating equipment for
Madison Heights, MI 48071 case hardening, tempering, annealing, bonding,
800.624.6297 brazing, strip/slab heating, galvanic annealing, and
www.ihs-usa.com other applications.

Inductotherm 10 Indel Ave. Inductotherm manufactures coreless and channel-type

Corp. Rancocas, NJ 08073 induction furnaces, and induction melting, holding,
888.463.8286 heating and pouring systems for virtually all metals.
www.inductotherm.com Furnace capabilities range from coffee cup size
melting a few troy ounces of precious metals to
furnaces holding hundreds of tons of iron. Induction
power supply systems that accompany these furnaces
range in size from 20 kW to 42,000 kW.

©2013 ACEEE Summer Study on Energy Efficiency in Industry 3-11

 Manufacturer Description
Pillar Induction 21905 Gateway Road Pillar products include solid state power supplies,
Co. Brookfield, WI 53045 prototype/production heat treating systems, and
800.558.7733 specialized total induction solutions. Applications of
www.pillar.com Pillar products range from induction annealing,
hardening, tempering, drying, through heating,
brazing, melting, and coating.
Radyne Corp. 211 West Boden St. Radyne designs, manufactures, and sells advanced
Milwaukee, WI 53207 induction power supplies, induction coils, heat
800.236.8360 stations, coils, scanning systems, brazing systems,
www.radyne.com wire, rod, and cable processing systems, pipe coating
systems, and systems for process automation.
RDO Enterprises 50 East Johnston St. ROD Induction offers induction systems for induction
Washington, NJ 07882 heating, induction casting equipment for dental,
908.835.7222 jewelry and industrial casting trades (titanium),
www.rdoent.com induction melting systems with tilt-pour furnaces
(from 5 to 200 kW in power) for all metal melting
industries, stand-alone induction melting equipment
for small lot melting (precious metal melting and
industrial alloys), and micro-welding equipment for
ferrous, non-ferrous and titanium alloys.
Taylor-Winfield Hubbard-Thomas Road Taylor-Winfield offers a variety of induction heating
Corp. Brookfield, OH 44403 power supplies for various induction heating
330.448.4464 applications, process automation (work stations,
www.taylor-winfield.com scanners, automated systems), support services and a
development laboratory.
Trithor GmbH 999 Baker Way, Suite 150 SC Power Systems specializes in high-temperature
and Bültmann San Mateo, CA 94404 superconducting (HTS) products, including induction
GmbH 415.407.2366 heaters using 1G and 2G HTS wires, current leads,
represented in the www.scpowersystems.com and coils. Trithor’s HTS induction heaters are
U.S. by SC available in standard sizes of 0.25 MW and 2 MW;
Power Systems they reduce energy use by almost half compared to
conventional induction heating.
Xaloy 1399 County Line Road Xaloy is a manufacturer of high-performance
New Castle, Pennsylvania 16107 machinery components and equipment for the plastics
724.656.5600 industry, such as injection molding, extrusion, and
www.xaloy.com other processes. One such product line heats the barrel
of injection molding machines by induction heating,
which cuts energy costs and improves temperature
control compared with conventional heater bands.

Conclusion
Technological innovations of efficient induction solutions are discussed in this paper,
namely, flexible multi-coil power supply with current control for each coil, development of a
multi-strand conductor for industrial induction heating, energy recovery on coil cooling water
with “Predictable Function Control” (PFC). New numerical models are developed and adapted to
the various needs: simplified multi-coil model for power electronic control, homogenization
technique for multi-strand wire. Work is on going to reach industrial applications within 2014.

3-12 ©2013 ACEEE Summer Study on Energy Efficiency in Industry

 Acknowledgement
This work has been supported by French Research National Agency (ANR) through
“Efficacité énergétique et réduction des émissions de CO2 dans les systèmes industriels”
program (project ISIS n°ANR-09-EESI-004).

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©2013 ACEEE Summer Study on Energy Efficiency in Industry 3-13