U.S. patent application number 12/667761 was filed with the patent office on 2011-01-06 for transport refrigeration series hybrid power supply.
This patent application is currently assigned to CARRIER CORPORATION. Invention is credited to Nader S. Awwad, John R. Reason.
Application Number | 20110000244 12/667761 |
Document ID | / |
Family ID | 40228862 |
Filed Date | 2011-01-06 |
United States Patent
Application |
20110000244 |
Kind Code |
A1 |
Reason; John R. ; et
al. |
January 6, 2011 |
Transport Refrigeration Series Hybrid Power Supply
Abstract
A series hybrid power supply system for a trailer box
refrigeration system is disclosed. The trailer box refrigeration
system may use either a DC or an ac motor to power the compressor.
The power system alternator produces power to power refrigeration
system loads.
Inventors: |
Reason; John R.; (Liverpool,
NY) ; Awwad; Nader S.; (Baldwinsville, NY) |
Correspondence
Address: |
BACHMAN & LAPOINTE, P.C. (UTC)
900 CHAPEL STREET, SUITE 1201
NEW HAVEN
CT
06510-2802
US
|
Assignee: |
CARRIER CORPORATION
Farmington
CT
|
Family ID: |
40228862 |
Appl. No.: |
12/667761 |
Filed: |
July 6, 2007 |
PCT Filed: |
July 6, 2007 |
PCT NO: |
PCT/US07/15673 |
371 Date: |
January 5, 2010 |
Current U.S.
Class: |
62/323.3 |
Current CPC
Class: |
B60L 1/02 20130101; Y02T
10/72 20130101; B60L 1/003 20130101; F25B 2327/00 20130101; B60L
2210/20 20130101; F25D 11/003 20130101; Y02T 10/88 20130101; B60H
1/00428 20130101; Y02T 10/725 20130101; F25B 27/00 20130101 |
Class at
Publication: |
62/323.3 |
International
Class: |
F25B 27/00 20060101
F25B027/00 |
Claims
1. A series hybrid mobile refrigeration power supply system
comprising: an engine coupled to an alternator, the alternator
configured to provide an alternating current output; a rectifier
bridge coupled to the output of the alternator, the rectifier
bridge configured to convert alternating current to direct current;
a distribution bus coupled to the rectifier bridge to distribute
direct current to a plurality of mobile refrigeration system loads;
and a direct current compressor motor electrically coupled to the
distribution bus using a contactor as a switching device, the
contactor energizes the compressor motor when required by
refrigeration cooling demand.
2. The system according to claim 1 wherein the engine is a gasoline
engine.
3. The system according to claim 1 wherein the engine a diesel
engine.
4. The system according to claim 1 wherein the alternator outputs
single phase ac.
5. The system according to claim 1 wherein the alternator outputs
polyphase ac.
6. An electric transport refrigeration system used to cool a
trailer box comprising: an engine coupled to an alternator, the
alternator configured to provide an alternating current output; a
rectifier bridge coupled to the output of the alternator, the
rectifier bridge configured to convert the alternating current to
direct current; a distribution bus coupled to the rectifier bridge
to distribute direct current to a plurality of electric transport
refrigeration system loads; an inverter coupled to the direct
current bus, the inverter configured to invert the direct current
to alternating current; and an alternating current compressor motor
electrically coupled to the inverter using a contactor as a
switching device, the contactor energizes the compressor motor when
required by refrigeration cooling demand.
7. The system according to claim 6 wherein the engine is a gasoline
engine.
8. The system according to claim 6 wherein the engine a diesel
engine.
9. The system according to claim 6 wherein the alternator outputs
single phase ac.
10. The system according to claim 6 wherein the alternator outputs
polyphase ac.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates generally to the field of transport
refrigeration systems. More specifically, the invention relates to
transport refrigeration systems employing a series hybrid power
supply outputting direct current (DC) to power either a DC or
alternating current (ac) compressor motor.
[0002] Transport refrigeration systems such as those used on truck
trailers, typically employ a mechanically coupled shaft driven
compressor or an electric motor driven compressor. In the
mechanical scheme, an engine such as a diesel is either directly or
indirectly coupled to the refrigeration compressor. The engine may
also drive the refrigeration condenser fans, evaporator fans, and
other components through additional mechanical drives using
pulleys, V-belts and the like.
[0003] For mechanical refrigeration systems, electric power is
limited. Usually, the only available power is 12 VDC that is
available from the refrigeration system engine battery. This low
voltage may be used to supply power for lighting within a trailer
box or for a lift gate mechanism.
[0004] In the electrical scheme, the engine is coupled to an
alternator which provides single or polyphase ac power for all
refrigeration loads. Refrigeration loads typically include a
compressor motor, condenser fan motors, evaporator fan motors,
electric defrosting heaters, and other electric loads.
[0005] What is desired is a system that provides DC to power DC and
ac loads.
SUMMARY OF THE INVENTION
[0006] The inventors have discovered that for electrical transport
refrigeration systems, a DC distribution for DC motors provides
less expensive motor speed control than ac motors, a lower cost
load distribution bus since the number of conductors is reduced as
compared with polyphase ac systems as well as the number of
contactor poles, and the inherent simplicity in understanding DC
systems.
[0007] A series hybrid power supply system using a DC distribution
bus is taught for a trailer box refrigeration system. The trailer
box refrigeration system may use either a DC or an ac motor to
power its associated compressor. The series hybrid alternator
produces power which is full wave rectified for DC refrigeration
system loads.
[0008] One aspect of the invention provides a series hybrid mobile
refrigeration power supply system for an electric transport
refrigeration system cooling a trailer box. Systems according to
this aspect of the invention comprise an engine coupled to an
alternator for providing an alternating current output, a rectifier
bridge coupled to the output of the alternator for converting the
alternating current to direct current, a distribution bus coupled
to the rectifier bridge for distributing direct current to a
plurality of mobile refrigeration system loads, and a direct
current compressor motor electrically coupled to the distribution
bus using a contactor as a switching device to energize the
compressor motor when required by cooling demand.
[0009] Another aspect of the invention provides a system for
providing electric power for an electric transport refrigeration
system used to cool a trailer box. Systems according to this aspect
of the invention comprise an engine coupled to an alternator for
providing an alternating current output, a rectifier bridge coupled
to the output of the alternator for converting the alternating
current to direct current, a distribution bus coupled to the
rectifier bridge for distributing direct current to a plurality of
loads, a compressor motor contactor coupled to the direct current
bus, an inverter coupled to the compressor motor contactor for
inverting the direct current to an alternating current supplied to
the compressor motor when required by cooling demand.
[0010] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is an exemplary schematic diagram for a series hybrid
AC alternator outputting dc to power a dc compressor motor for a
trailer box refrigeration system.
[0012] FIG. 2 is an exemplary schematic diagram for a series hybrid
AC alternator outputting dc to power an AC compressor motor for a
trailer box refrigeration system.
DETAILED DESCRIPTION
[0013] Embodiments of the invention will be described with
reference to the accompanying drawing figures wherein like numbers
represent like elements throughout. Further, it is to be understood
that the phraseology and terminology used herein is for the purpose
of description and should not be regarded as limiting. The use of
"including," "comprising," or "having" and variations thereof
herein is meant to encompass the items listed thereafter and
equivalents thereof as well as additional items. The terms
"mounted," "connected," and "coupled" are used broadly and
encompass both direct and indirect mounting, connecting, and
coupling. Further, "connected" and "coupled" are not restricted to
physical or mechanical connections or couplings.
[0014] Shown in FIG. 1 is a first embodiment 101 of a series hybrid
dc power distribution system for a mobile refrigeration unit. In a
series hybrid configuration, a gasoline or diesel engine 103 turns
a synchronous alternator 105 to generate power for an electric
motor 107 that operates a compressor 109 for the mobile
refrigeration system. The engine 103 never directly powers the
compressor 109.
[0015] The alternator 105 generates a voltage at a frequency 111
that vary linearly with the angular velocity of the engine 103. The
engine 103 speed 113 may be unregulated or regulated using an
engine governor (not shown). In a preferred embodiment, the system
is designed to operate at a plurality of engine speeds 113, the
selection of which is determined by a controller to meet the
required conditions of the refrigerated space.
[0016] The alternator 105 may output single phase or polyphase ac
and is used to provide power to the compressor 109 drive motor 107,
and may power condenser fan motors, electrically powered evaporator
fan motors, serpentine heater elements, evaporator coil heaters,
and a host of electrical and electronic control devices such as a
suction modulation valve solenoid, a display keyboard module, and
the like (not shown).
[0017] The structure of the integrally mounted engine driven
alternator 105 unit is small to allow it to be easily coupled
directly to the drive shaft of an engine 103. As a result, a single
rotatable drive shaft which is common to both the alternator 105
and engine 103 allows the alternator 105 and engine 103 to be
configured to operate as a single unitary mounted unit. The engine
103 may be coaxially coupled to the alternator 105, or may be
coupled using an intermediate power transmission device. Various
types of mechanical drive mechanisms including gear trains and
other known mechanical drive devices may be used.
[0018] Coupled to the output of the alternator 105 is a bridge
rectifier 115 for single phase alternator 103 outputs and/or a
polyphase diode bridge 115 for polyphase alternator 103 outputs. A
bridge rectifier (diode bridge) is an arrangement of diodes
connected in a bridge circuit that provides the same polarity of
output DC voltage for any polarity of input ac voltage. The bridge
rectifier provides full wave rectification from a single phase or
polyphase ac input.
[0019] The rectified DC is output from the rectifier 115 onto a
distribution bus 117 for distributing power to all DC fed
loads.
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