Note: Descriptions are shown in the official language in which they were submitted.
L.TU57es CA 02403762 2002-09-20
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Description
Electric Suspended Conveyor With Contactless Energy Transmission
The invention relates to an electric telpher with non-
contact power transmission from a feeder and return
conductor conducted along a slide rail and connected to a
higher-frequency AC power supply via a current collector
configured as a U-shaped ferrite core with windings that
encompasses the supply line to the control and power
circuits of a transfer unit that can travel on the slide
rail.
Non-contact inductive transmission of electrical power to
rail-guided transfer units equipped with electric
consumers has been known for a long time. For example, DE
44 46 779 describes an arrangement for non-contact
inductive power transmission to electrically powered
transfer units that are moved on a closed track. In this
arrangement, a feeder fed by a higher-frequency AC power
supply is kept at a spacing from the slide rail and
encompassed by the respective current collector that is
mounted to the respective transfer unit and connected to
the drive motor and the control circuit. The current
collector consists of a U-shaped ferrite core with a
winding around its limbs. Transmission of electrical
power from the primary feeder to the secondary windings
is based on the transformer principle, and the various
consumers on the transfer unit are supplied a voltage
level in accordance with their power needs. As the
control circuit of the transfer unit, however, requires a
considerably lower voltage (24V) than the power circuit,
an enormous switching effort is required to supply the
24V DC from the 560V DC voltage provided by the current
collector. A similar effort is required for the return
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conductor of the primary power supply that in DE 44 46
779 is formed by the sidewalls of a casing that almost
completely encompasses the current collector.
It is therefore the problem of this invention to disclose
an electric telpher with non-contact electrical power
transmission that can be efficiently produced as regards
current transfer from the primary supply to the various
consumers of the transfer units.
This problem is solved according to the invention by the
electric telpher with non-contact power transmission
comprising the characteristics described in claim 1.
The inventive idea is to use the aluminum slide rail for
the transfer units of the telpher as return conductor.
When combining this characteristic with an arrangement of
two separate windings on the U-shaped ferrite core
(current collector) to be able to provide two independent
direct currents of different voltages and load capacities
for the control and power circuits and thereby
considerably simplify the switching effort required for
providing the lower voltage, overall expenditure of
supplying power to the consumers of the transportable
units is considerably reduced.
The inventive power supply to the transfer units is, of
course, not limited to suspended or telpher systems but
may also be used in a similarly advantageous way with
other conveying equipment in which a transfer unit is
moved along a rail and that operates on a non-contact
power supply. This is a more effortless way to make use
of the known advantages of non-contact power
transmission, such as high operational reliability even
under difficult operating conditions, minimum maintenance
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and wear, low noise, high conveying speed, and high
efficiency.
The subclaims and the description of an exemplary
embodiment below reveal other important characteristics
of the invention, for example regarding the supply of a
stabilized medium-frequency current to the primary
circuit, positioning and attachment of the feeder in a
specially designed bracket that can be attached to the
slide rail, the electrical configuration of the current
collectors, or the design of junction points of the
telpher.
An embodiment of the invention is explained in greater
detail below with reference to the figures. Wherein:
Fig. 1 is a schematic view of an arrangement for non-
contact transmission of electrical power to a
transfer unit that can be moved along the slide
rail of an electric telpher system;
Fig. 2 is a sectional, partially perspective view of a
feeder bracket that can be locked into the
slide rail of an electric telpher system and is
mechanically coded for position detection;
Fig. 3 shows a switching arrangement for feeding power
into the primary circuit of an arrangement for
non-contact power transmission;
Fig. 4 shows a circuit wiring diagram of the bridge
rectifier to be provided according to Fig. 3;
Fig. 5 shows a circuit wiring diagram of the
stabilized power supply for power feeding as
shown in Fig. 3;
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Fig. 6 shows a circuit wiring diagram of a current
collector to be provided for the secondary
circuit;
Fig. 7 shows the supply provided for a mobile feeder
in the area of a telpher junction;
and
Fig. 8 shows a junction area according to Fig. 7, but
comprising an upstream safety block.
The arrangement for non-contact power transmission as
shown in Fig. 1 comprises an aluminum slide rail for
guiding a transfer unit (not shown) for carrying and
transporting loads that is equipped with a control
circuit and a power circuit. A feeder bracket 2 made of a
non-conducting, preferably synthetic material is mounted
to a slide rail 1, said feeder bracket comprising a
holding groove 3 in its free end placed at a spacing to
said slide rail 1 (see Fig. 2) to receive a feeder 4 in
the form of a high-frequency litz wire. As Fig. 2 shows,
this feeder bracket 2 further comprises a mechanical
coding that is used by a scanner mounted to the transfer
unit (not shown) to ensure absolute position detection.
Where the slide rail 1 has a bend, the feeder bracket 2
is made of short segments (not shown) which can be locked
into compact holders la attached to one longitudinal side
of the slide rail 1. The feeder bracket 2 protrudes into
a current collector 6 that is configured as a U-shaped
ferrite core 6.1 with one winding Nol or N02,
respectively, on each of its limbs. The windings Nol and
N02 are each connected to an electronic collector circuit
AE1 or AE2, respectively, and these two circuits provide
two separate supply voltages Vol and V02 to supply the
transfer unit with direct current (Ipl; 102). The windings
~78g CA 02403762 2002-09-20
Nol and N02 have different ratings so that the voltages Vol
and V02 are different in size and load capacity, one
suitable for the control circuit and one suitable for the
power circuit of the respective transfer unit. Thus
5 wiring and switching requirements for the power
electronics are rather low. The low voltage may also be
used to feed small consumers. The feeder 4 is located
inside the U-shaped ferrite core (current collector 6) at
a minimum depth of 40% of the overall depth of the core
to ensure the creation of a magnetic flux in the ferrite
core and provide an adequate magnetomotive force (N01 =
Ioi. No2 = 102) =
As shown in Fig. 3, the primary circuit of the
arrangement consisting of the feeder 4 and a return
conductor 7 is supplied with power from a three-phase
low-voltage system via a six-pulse bridge rectifier that
provides a link voltage V. A circuit wiring diagram of
the bridge rectifier 8 is shown in Fig. 4. A PWM
rectifier inverter 10 that works on two LC components 11
and an output transformer 12 is provided downstream as a
stabilized power supply 9 (a circuit diagram of which is
shown in Fig. 5) downstream from the bridge rectifier 8
so that a constant medium-frequency current is supplied.
The PWM rectifier inverter 10 determines the output
frequency of the constant current while the two LC
components 11 are responsible for the quality of the
sinusoidal wave shape of the constant current and for
limiting the noise spectrum along the feeder.
The circuit diagram as shown in Fig. 3 represents two
current collectors 6, each of which connected to a
consumer (not shown), that can be moved along the feeder
and require different power levels. A circuit wiring
diagram of a current collector 6 that can travel along
the feeder 4 and is equipped with the electronic
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collector circuits AE1 and AE2 as outlined in Fig. 1 for
different voltages Vol and V02 is shown in Fig. 6. A
control unit (RS) is labeled with reference symbol 13 in
the electronic collector circuit AE2 for oscillating
circuit quality. There are no feedback effects on the
adjacent current collector 6 due to the stabilized power
supply. Compensation modules 22 are provided along the
guideway formed by the return conductor 7 and the feeder
4 to compensate the inductive voltage portions und thus
to increase the working efficiency of the system; these
modules are shown as capacitors in Fig. 3.
While the feeder 4 is a finely stranded litz wire with
reinforced insulation at mechanically critical points,
slide rail 1 is used as return conductor 7. The slide
rail segments 1 that are used as return conductor 7 have
low-resistance terminations for the required
equipotential bonding, while flexible earthing strips
(not shown) are provided on all stretching points. By
means of specific modulation and demodulation methods,
feeder 4 can also be used as a communication channel for
programming and remote control of the transfer units.
Communication with the control unit that is connected to
the transfer unit (not shown) takes place here in the
known way using infrared modules that are integrated into
the control unit, or radio modules.
Each control unit is routinely equipped with an onboard
infrared module that is used for programming and remote
control of the propulsion gear of the transfer unit.
Furthermore, these mobile infrared modules may
communicate with special read-write stations at selected
points along the guideway which in turn are managed by
the higher-order system control unit. This is where the
control units exchange status and command information and
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store this data in a no-volt protected memory. These IR
modules can also be used for start/stop functions and the
like, if required.
As an alternative to IR technology, mobile radio modules
can be used that can optionally be integrated into the
control unit but allow permanent communication with
system control. As the range of transmission is limited
in a rough industrial environment, an interconnection of
fixed base stations is used here, each of these stations
representing a cell. These individual cells overlap so
that all transfer units on the guideway can be reached
safely. This interconnection of radio stations is
controlled and monitored in such a way that propulsion
gear can be logged off without data loss when the
transfer unit leaves a cell and safely logged on to the
next cell. This equipment is suitable for rough allotment
estimates. If combined with position detection, the user
gets a transparent track model of all vehicles and may
apply higher-order control mechanisms depending on the
communication bandwidth in system control.
The control unit is equipped with a scanner (not shown)
that carries out position detection along the travel path
using mechanical coding 5. This information is also used
for internal motor control. Jolts or any other
unsteadiness in the absolute code curve can be stored in
a no-volt protected memory the control unit, which means
there can be greater fault tolerance when installing the
absolute code rail 5. This function is most useful when
the scanner scans the feeder brackets 2 that carry a
mechanical coding 5.
The control unit is designed in such a way that it can
either directly actuate a standard gearbox motor with a
wheel that is mounted on the drive end and performs both
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driving and load-bearing functions and an
electromechanical brake or a linear motor unit with an
electromechanical brake arrangement that functions as a
holding brake.
As shown in Fig. 7, mobile feeders 14 that can be
supplied with high-frequency power from a stationary
feeder module 15 located in the vicinity of the track and
connected to the feeder 14 via a trailing cable and a
mobile feeder module 17, are provided in junction areas
of the telpher such as points, intersections, lifting,
lowering, and shunting stations.
As Fig. 8 shows, emergency stops and safety blocks 19 are
provided in front of and inside junctions that are
connected to permanently installed supply modules 20 in
the vicinity of the track to create partial shutdown
segments using conventional switching logic. The supply
module 20 is configured so that it can be connected to a
feeder module 17 via a trailing cable 21.
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List of reference symbols
1 slide rail (return cable)
la compact holder
2 feeder bracket
3 holding groove
4 feeder
5 mechanical coding (slot coding)
6 current collector (SAE1, SAE2)
6.1 ferrite core
7 return conductor
8 six-pulse bridge rectifier
9 stabilized power supply
10 PWM rectifier inverter
11 LC components
12 output transformer
13 control unit (RS)
14 mobile feeder
15 stationary feeder module (VME)
16, 21 trailing cable
17 mobile feeder module (VME)
18 mobile section
19 safety block
20 supply module (VMS)
22 compensation modules
AE1 electronic collector circuit
AE2 electronic collector circuit
Nol, N02 windings of 6
Uol, U02 supply voltage for transfer unit
UZ link voltage
I1 constant medium-frequency current
