U.S. patent application number 14/689631 was filed with the patent office on 2016-08-11 for high efficiency hydronic circulator with sensors.
The applicant listed for this patent is Douglas Bird, Robert F. Birkenstock, JR., Vladislav Michev Stakev, David E. Sweet, Steve Thompson. Invention is credited to Douglas Bird, Robert F. Birkenstock, JR., Vladislav Michev Stakev, David E. Sweet, Steve Thompson.
Application Number | 20160230767 14/689631 |
Document ID | / |
Family ID | 56566644 |
Filed Date | 2016-08-11 |
United States Patent
Application |
20160230767 |
Kind Code |
A1 |
Thompson; Steve ; et
al. |
August 11, 2016 |
HIGH EFFICIENCY HYDRONIC CIRCULATOR WITH SENSORS
Abstract
A highly efficient circulator system is provided, useful for
hydronic systems, including both heating and cooling systems. The
stand-alone circulator motor is controllable by input from certain
sensors, preferably thermal sensors, which provide data enabling
the controller of the brushless pump motor to vary its flow output
to meet changes in systems loads. The circulator has a ceramic
permanent magnet rotor, such as a ferrite, with an electronically,
preferably sinusoidally, commutated, electro-magnetic stator
controlling the input of electrical power.
Inventors: |
Thompson; Steve; (Calgary,
CA) ; Stakev; Vladislav Michev; (South Easton,
MA) ; Birkenstock, JR.; Robert F.; (Warwick, RI)
; Bird; Douglas; (Narragansett, RI) ; Sweet; David
E.; (Old Lyme, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Thompson; Steve
Stakev; Vladislav Michev
Birkenstock, JR.; Robert F.
Bird; Douglas
Sweet; David E. |
Calgary
South Easton
Warwick
Narragansett
Old Lyme |
MA
RI
RI
CT |
CA
US
US
US
US |
|
|
Family ID: |
56566644 |
Appl. No.: |
14/689631 |
Filed: |
April 17, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62115050 |
Feb 11, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02K 11/044 20130101;
H02K 11/33 20160101; H02K 11/05 20160101; F04D 13/064 20130101;
F04D 13/0686 20130101; F04D 15/0066 20130101 |
International
Class: |
F04D 15/00 20060101
F04D015/00; F04D 13/06 20060101 F04D013/06; H02K 11/04 20060101
H02K011/04; F04D 1/00 20060101 F04D001/00; H02K 1/27 20060101
H02K001/27; H02K 11/00 20060101 H02K011/00 |
Claims
1. In a stand-alone, wet rotor circulator for a hydronic system,
the circulator comprising a centrifugal impeller and an
electrically-powered variable frequency DC motor operationally
connected to the centrifugal impeller to drive the impeller, the
variable frequency DC motor comprising a permanent magnet rotor and
a system of stator coils powered by a variable DC current; an
electronic control system, electrically connected to the stator
coils of the motor, the electronic system comprising a rectifier,
for rectifying AC current to DC current, an electronic commutation
system and an electronic variable frequency drive ("VFD") control
system, for controlling the speed of the motor by producing an
artificial variable voltage frequency for the rectified DC current
from the rectifier, for powering the pump motor, an electrical data
signal connection to receive data signals reflecting the output of
a thermostatic sensor, an operational connection from the
electrical data signal connection to the VFD to pass any data
signals to the VFD, and an electrical circuit connection between
the rectifier portion of the control system and a source of AC
current; the improvement comprising: the permanent magnet rotor
being formed of a ferrite magnet; the rectified DC voltage being
maintained at the native voltage of the AC current, and an IGBT
power module for converting the DC current to a sinusoidally
varying DC voltage from a rectified AC power supply, controlled by
the VFD, for powering the stator coils; the VFD system varying the
frequency of the sinusoidally variable current in response to
changes in system loads, as signaled by the data signal from at
least one thermal sensor; the electronic commutation system working
in conjunction with the VFD to control the speed of the
electrically powered motor, so as to result in a highly efficient
and substantially noise-free motor.
2. In the stand-alone, wet rotor circulator system for the hydronic
system of claim 1, wherein the variable frequency DC current has a
voltage in the range of from about 160 Volts to about 350
Volts;
3. In the stand-alone, wet rotor circulator system for the hydronic
system of claim 1, the electronic system comprising two printed
circuit boards, one printed circuit board for receiving and
rectifying AC line current and for receiving and interpreting data
from at least one thermostatic sensor, and a second printed circuit
board for controlling the motor speed by varying the voltage change
frequency of the power to the stator; wherein the second printed
circuit board comprises a microcontroller, which interprets the
thermal data received from the thermal sensor via the first printed
circuit boards, and controls the pump operation to maintain the
necessary fluid flow rate of the hydronic fluid based upon such
thermal data.
4. In the stand-alone, wet rotor circulator system for a hydronic
system of claim 2, further comprising connections attached to the
first printed circuit board for selecting a specific program for
controlling the operation of the hydronic circulator.
5. In the stand-alone, wet rotor circulator system for a hydronic
system of claim 3, further comprising manually operable controls
for selecting a specific program to operate the pump in accordance
with the requirements of the hydronic system; an LCD screen for
displaying indications of the program selected; and connections
between the manually operable controls and the first printed
circuit board and the LCD screen.
6. In the stand-alone, wet rotor circulator system for the hydronic
system of claim 4, wherein the program operating the VFD acts to
maintain a designated temperature differential between the outlet
from the hydronic fluid source and the return line to the hydronic
fluid source.
7. In the stand-alone, wet rotor circulator system for the hydronic
system of claim 4, wherein the hydronic system includes a boiler,
and wherein the program operating the VFD acts to prevent the
return of hydronic fluid to the boiler at a temperature below that
necessary to prevent interference with the proper operation of the
boiler or to prevent damage to the boiler.
8. In the stand-alone, wet rotor circulator system for the hydronic
system of claim 7, comprising a thermistor located at the return to
the boiler, and wherein the program controlling the VFD acts to
slow down the flow of hydronic fluid so as to return a smaller
amount of fluid to the boiler until the space to be heated is
warned up to the point where the returning fluid will not cause
damage to the boiler.
9. In the stand-alone, wet rotor circulator system for the hydronic
system of claim 7, comprising a thermistor located at the return to
the boiler, and wherein the program controlling the VFD acts to
slow down the flow of hydronic fluid so as to return a smaller
amount of fluid to the boiler until the space to be heated is
warned up to the point where the returning fluid will not cause
damage to the boiler.
Description
[0001] This application claims the benefit of priority pursuant to
35 U.S.C. 119(e) from a U.S. Provisional Patent Application No.
62/115,050 filed on Feb. 11, 2015, the text of which is fully
incorporated by reference herein as if repeated below.
[0002] The present invention is directed to a highly efficient
circulator system, useful for hydronic systems, including both
heating and cooling systems. Specifically, this stand-alone
circulator is controllable by input from certain sensors,
preferably thermal sensors, which provide data enabling the
controller of the brushless pump motor to vary its flow output to
meet changes in systems loads. The circulator has a molded,
ceramic, such as a ferrite, permanent magnet rotor with an
electronically, preferably sinusoidally commutated,
electro-magnetic stator controlling the input of electrical
power.
BACKGROUND OF THE INVENTION
[0003] It has previously been well known to provide a thermal
sensor-controlled, electronically commutated, permanent magnet
motor, including a wet rotor, for use in hydronic heating systems.
One such product has been previously sold by Taco, Inc., under the
name Bumble Bee or Model HEC-2, variable speed circulator. That
device has a high efficiency DC motor controlled through a
programmable PC board by thermal sensors constantly sending data to
the printed circuit board ("PCB"). Bumble Bee included a permanent
magnet rotor directly connected to the centrifugal impeller of the
pump and the pump is of the wet rotor type. The Bumble Bee rotor
was formed of a state-of-the-art, compression bonded, rare earth
(NdFeB) permanent magnet with an anticorrosion coating, and formed
over a low carbon steel back-iron seated on the rotor shaft, which
in turn is connected directly to the pump impeller, the stator was
powered with a low voltage, e.g., 12 VDC electrical power input
controlled by the control board programmed to follow a
trapezoidally variable commutation. The use of the rare earth rotor
magnet and the use of relatively low input voltage of 12 volts DC,
resulted in a motor which, although relatively highly efficient,
was costly, utilized a trapezoidal control strategy, and resulted
in a motor that was noisier than desirable for residential use.
BRIEF SUMMARY OF THE INVENTION
[0004] This invention provides a highly efficient, substantially
noise-free, stand-alone wet rotor circulator system for a hydronic
heating or cooling system. The circulator system comprising a
centrifugal impeller and an electrically powered, rotary motor,
controlled by an electronic, variable frequency drive (VFD) control
system for controlling the speed of the motor by varying the
frequency of the rectified DC current supplied to power the stator
coils of the motor. The present electric motor driven, centrifugal
circulator system invention goes contrary to the prevailing wisdom
of using a small rare earth magnet as the motor rotor and a stepped
down trapezoidally varying voltage, e.g., 12 Volts, to drive the
motor.
[0005] Preferably, in accordance with this invention, the highly
efficient, stand-alone circulator system for a hydronic heating or
cooling system, is controlled by at least one thermal sensor placed
in the flow conduits of the hydronic system, that provides data
allowing the pump controller to determine the optimal output flow
of the pump under specific temperature differential conditions.
Further, preferably, in accordance with this invention, so as to
operate at greater efficiencies, while producing less noise and
being capable of operating at higher temperatures, a ferrite
permanent magnet rotor is used, together with a system of stator
coils powered by a non-stepped down, sinusoidally varying DC
voltage from a rectified AC power supply, i.e. either a 115-120V AC
rectified to about 170 Volts DC or a 230-240V AC, rectified to
about 340 Volts DC, and operated by a variable frequency electronic
drive ("VFD") system. The VFD system in the preferred embodiment
smoothly reacts to changes in system loads, as signaled by the
thermal sensors, to determine the pump flow required, with little
or no noise and with a minimal use of power. It also avoids the
initial cost and maintenance and operating power losses, of a
step-down transformer.
[0006] The pump is powered by an electronically commutated,
permanent magnet rotor motor, with a wet rotor circulator, to
deliver the necessary flow for the system. The VFD, which
interprets the data received from the thermal sensor or sensors, is
integrated into the main motor control electronics and controls the
pump operation to maintain the necessary fluid flow rate of the
hydronic fluid to meet the heat energy requirement for the system.
The thermal sensors measuring the temperature of the heating or
cooling fluid at pre-determined points in the system provide the
necessary data to operate the VFD to meet demand most
efficiently.
[0007] Much of the reduced energy usage of these high efficiency
circulators, stems from the capability of their VFD's to
electronically modulate speed as required to meet demand. The
present invention has the additional advantage of relatively low
electric current usage, which also reduces the heat developed in
the motor, and improves efficiency. The controller presents at
least four modes of operation for the circulator, controlled by use
of the data from one or more thermal sensors to manage the flow
required to meet the thermal demands of the hydronic system:
Temperature differential (or Delta T), Temperature Setpoint-Heat,
and Temperature Setpoint-Cool, and a drain back system, for
protecting the water boiler, during a heating cycle when the
hydronic liquid returning to the boiler is too cool. These modes
are described below.
[0008] Delta T--Measures the temperature differential typically
across a zone and adjusts the flow rate to ensure that the hydronic
fluid dispenses optimum thermal energy into the room to be heated,
to maintain a substantially constant, comfortable temperature.
Typical prior installations are often over circulated, where the
flowing fluid return temperature is not significantly lower than
the supply temperature. This results in wasted energy by the
circulator operating at excessive fluid velocity, resulting in
excessive noise and poor efficiency of the boiler and overall
system. The Delta T mode prevents this over circulation by ensuring
a fixed temperature differential from Supply to Return. A prior art
high efficiency, proportional pressure pump does not reduce flow
based on the thermal demand of the system and would need to be
sized similarly to a single speed pump sold today.
[0009] Temperature Setpoint Heat--This mode is for the circulator
to be used most commonly as an injection pump to a radiant floor
system. The pump will add heat to the recirculating loop in the
floor to maintain a constant floor temperature using a target value
and one sensor in a PI (Proportional Integrated) controller. This
circulator is powered when the thermostat for the loop is calling,
but will reduce power, speed and flow when the thermal needs of the
system are met. There is also an option for the circulator to enter
a standby state so as to prevent adding too much heat to the
system, or to prevent a shock to the boiler when the there is cold
water in the flow system returning to the boiler. This is possible,
however, because the sinusoidal control system, unlike the
trapezoidal system, can reduce noise and achieve a quieter motor.
Further, the thermal sensors also provide for a boiler protection
feature to prevent thermal shock when starting up a cold system to
heat a venue, by initially reducing the amount of hot water
injected into the system so as to limit the amount of redirected
cold water to the boiler return. An additional application allows
the circulator to pump hot water into a fan coil system for
heating. The thermal sensor is placed in the duct and will signal
the pump to increase speed to provide more hot air from the system
to maintain a fixed air temperature to the duct. A bypass or shunt
mode can also be provided for a heating system.
[0010] Temperature Setpoint Cool--This is the inverse of Setpoint
Heat and allows the circulator to pump cold water into a fan coil
system for air conditioning. The thermal sensor is placed on the
piping or in the duct and will signal the pump to increase pump
speed as well as fan speed, to provide more cool air from the
system. The Setpoint Cool also has a standby feature to prevent
excessive cooling in the system, to prevent condensation in an
air-cooled building.
[0011] Bypass or shunt mode--The pump operates when the temperature
of fluid or hydronic fluid returning to the boiler is below the
pre-set target temperature required to prevent damage from
condensing fluid or thermal shock. The pump activates to pump hot
water directly from supply to return and to thus increase the
temperature of the returning water to prevent boiler damage.
[0012] The present invention provides a much improved, more
efficient and less costly, electric motor, having at least equal
capability with regard to use for the variable pumping of hydronic
fluids for both heating and cooling. The structure of the present
invention utilizes an inexpensive ceramic ferrite permanent magnet
mounted directly to the rotor shaft and a direct input of rectified
AC line voltage, e.g., 170 volts DC or 340 volts DC, connected
directly to the pump motor electronic controller, to power the
motor. The present invention can be powered from the usual AC
electric circuit source of 115-120 volts, 60 Hertz, as available in
most U.S. residential units, or from a 240 V, 50 Hz current, as is
available in countries outside of North America or in commercial or
industrial locations in the U.S. In all cases the electronic
controller provides the pump motor with rectified, sinusoidally
varying, e.g., 170 volts DC or 340 volts DC current, resulting
directly from the rectification of the line AC current, to power
the motor, and for controlling motor speed by sinusoidally varying
the frequency of the rectified direct current. By incorporating a
PFC boost circuit into the system control boards, a bus voltage of
up to 400 VDC can be achieved.
[0013] The rotor and stator of the present invention are both
elongated, to meet the spatial requirements of the somewhat larger
ferrite magnet being used, and to be able to encompass the
increased number of turns of wire forming the stator, to achieve
the desired magnetic flux from the lower current flow to the motor
from the high voltage power, and the weaker ferrite magnet forming
the rotor.
[0014] For example, for a common small pump motor, a suitable rare
earth motor rotor, with an internal backiron, would be about 0.5
in. long, but when using a common ferrite magnet rotor, the rotor
must be elongated to about 1.4 ins. long, to achieve a similar
power output. However, it is well-known in the art to manufacture
an anisotropic ceramic ferrite magnet. When using an anisotropic
ceramic ferrite magnet, the magnetic flux can be greatly increased
(up to about 1.8 times that of a common ferrite magnet rotor),
depending upon the method of manufacture. So that, for example,
following the preceding examples, using an anisotropic ferrite
magnet rotor 1.4 ins. in length, allows for greater output and
efficiency, with lower noise, but is less costly than a rare earth
magnet.
[0015] The electronic commutation for the permanent magnet rotor
motor can be provided, by way of example only, by an operational
amplifier ("OPAMP") and a comparator, operating in combination with
the OPAMP, along with a microprocessor. These electronic control
elements are all mounted preferably in the motor case. This motor
is further improved by using the sinusoidal wave function for motor
control of this invention, which results in a far quieter and more
effective control system, and greatly improves the efficiency of
the controlled operation of the circulator. Electronic systems for
providing sinusoidally varying direct current voltage are well
known to the art and do not, themselves, form a part of this
inventive combination described herein. The lower current flow
reduces the heat generated in the motor, although the stator
further includes a greater number of wiring turns to compensate for
the lower current flow at the higher voltage, in order to obtain
the necessary magnetic flux.
[0016] As a result of the reduction in the inductance created
between the electrical coils and the ferrite permanent magnet which
does not include a back iron, as is commonly used with rare earth
magnets, and the ability to drive the system with greater force
without fear of demagnetization of the ferrite permanent magnet,
the system can be smoothly controlled, from a full stop to maximum
flow, by providing for sinusoidal changes in the magnetic flux from
the stator electromagnets created by the sinusoidally varying
direct voltage.
[0017] Moreover, the flux from a standard ceramic ferrite magnet
can be further increased by orienting the magnet so as to form an
anisotropic ferrite magnet. It is also well-known that the flux can
be increased further, again, without changing the ferrite material,
by forming a Halbach array, anisotropic ferrite magnet. By
increasing the flux, the number of wire turns in the stator need
not be increased, or increased less, as compared with the use of
rare earth permanent magnets. The advantages of the ferrite magnet
regarding inertness to the wet environment and maintaining magnetic
quality at higher temperatures, and the higher voltage and lower
current flow, remain, in each of the above cases.
[0018] This pump motor includes programmable circuits that are
capable of being readily programmed to operate in many different
configurations as is needed, depending upon the requirements of the
overall flow system. The necessary data are provided to the motor
controller from temperature sensors suitably placed in the flow
systems. Specifically, the algorithms that can be programmed into
each of the printed circuit boards, or the firmware, controlling
the motor, can provide for operation of the system under any of the
potential modifications, including inherently allowing the pump to
operate based upon a "A-temperature with pre-purge ramp up feature
algorithm", which provides for gradually increasing the speed of
the pump motor, and thus the flow rate in the flow system, until
the desired temperature differential is achieved; a "Temperature
Setpoint Cool algorithm"; "a close loop system with drain back
algorithm", especially useful for solar energy systems; a
"Temperature setpoint heat mode with protection of the boiler
algorithm", including the use of several temperature sensors in the
flow system; and "Boiler protection shunt or bypass mode." These
four modes are each part of the software programmed into the
controller chips connected into the pump controller microprocessor;
additional algorithms can be programmed in as deemed necessary for
other desired changes in the operational control of the pump
system, or operation under a wholly different program.
BRIEF SUMMARY OF THE DRAWINGS
[0019] FIG. 1 is a side elevation view of a circulator in
accordance with the present invention;
[0020] FIG. 1A is an exploded view of the circulator of FIG. 1;
[0021] FIG. 2 is a front, internal view showing the stator slots
and the rotor where the windings have not been applied to the
stator, so as to show the stator shoes and slots of the circulator
in FIG. 1;
[0022] FIG. 3 is an isometric view of the stator of FIG. 2,
including the windings and the electrical power connection
points;
[0023] FIG. 4 is an isometric, diagrammatic view of the permanent
magnet rotor of FIG. 1;
[0024] FIG. 4a is an isometric exploded view and an isometric view
of a prior art version of a permanent magnet rotor for a prior art
DC motor;
[0025] FIG. 5 is a front end view of the rotor of FIG. 4; and
[0026] FIG. 6 is a cross-sectional view along lines A-A of FIG. 5
of the permanent magnet rotor of FIG. 4;
[0027] FIG. 7 is an exploded view of the permanent magnet rotor of
FIG. 4;
[0028] FIG. 8 is an exploded view, showing the motor drive control
portion of the pump motor, and how it is attached to the main
casing of the pump-motor;
[0029] FIG. 8A is a detailed view of the motor drive control
printed circuit board, including the several elements of the
circuit;
[0030] FIG. 9 is an exploded view of the power supply control
section of the pump motor case, including the LED screen and the
power supply control printed circuit board;
[0031] FIGS. 9A and 9B are the front and back diagrammatic views,
respectively, of the printed circuit board controlling the power
supply to the pump motor;
[0032] FIG. 10 is a flow chart of the algorithm controlling the
circulator of the present invention for a closed loop solar heating
system, including a safety feature;
[0033] FIG. 11 is a flow chart for the algorithm for a drain back
system, including a safety feature;
[0034] FIG. 12 is a flow chart for the algorithm operating the
circulator in accordance with a temperature control including a
pre-purge start cycle;
[0035] FIG. 13 is a flow chart for an algorithm for operating the
circulator in a set point cooling mode;
[0036] FIG. 14 is a flow chart for an algorithm operating the
circulator of this invention under a set point heating mode,
including protection against damage to the boiler;
[0037] FIG. 15 is a flow chart for an algorithm for operating the
circulator of this invention with a boiler protection mode and
including operating a shunt/bypass.
[0038] FIGS. 16a-e are diagrammatic illustrations of flow systems
in the HVAC field in which the circulators of this invention are
useful.
[0039] FIG. 16a is a series loop system, including zone valves
which maintains a constant temperature differential across the
series of loops;
[0040] FIG. 16b is a multi-zone system of radiant manifolds with
loop actuators, again utilizing a constant Delta T maintained
across the entire system between the boiler output and the return
fluid to the boiler, while also providing boiler protection via a
by-pass line;
[0041] FIG. 16c is a set point heating system where the speed of
the circulator is programmed to be varied in order to maintain a
fixed temperature in either the supply sensor or the boiler return
sensor. In addition, there is a provision for boiler protection, by
decreasing circulator speed, and thus the flow rate, when the
liquid returning to the boiler is at too low a temperature to avoid
temperature shock to the boiler and resulting flue gas
condensation;
[0042] FIG. 16d is an alternative boiler protection system which
provides for a bypass in the event of extremely low temperature in
the return system, increasing flow rate from the circulator to
allow for the by-pass; and
[0043] FIG. 16e provides for a heating or cooling system where
cooled or heated air is blown into the desired location and the
circulator speed is programmed to be changed in accordance with the
necessary temperature requirement for the fan coil, specifically
whether a coolant or heating liquid is being circulated.
DETAILED DESCRIPTION OF THE INVENTION
[0044] Referring to the drawings, the circulator includes an
impeller 37, which is directly connected to a permanent magnet
rotor 8 in the pump motor. The impeller 37 is held within the
impeller chamber 7 and moves the fluid between the fluid inlet 4
and the fluid outlet (see fig IA). The motor is controlled by the
Central Processing Unit (the "CPU") and Digital Signal Processor
("DSP"), on the printed circuit board ("PCB") of the motor control
board, generally indicated by the numeral 116, which is directly
connected to the stator windings within the housing 9. A diagram of
the motor control PCB 116 circuitry is shown in FIG. 8a. The
details of the sensor and power control PCB are depicted in FIGS.
9, 9A, 9B, and is generally shown by the numeral 22 in FIG. 1A
[0045] The high voltage power is passed from the power control PCB
22 via the connectors TP6, TP7, to the motor control PCB 116
through the two-pin header J6.
[0046] The details of the stator are shown more fully in FIGS. 2
and 3, where the windings are shown in FIG. 3 indicated by the
numeral 47, around coil shoes 147, as shown in FIG. 2, before the
wire is wound around the coil shoes 148. These shoes are formed of
laminated layers and the windings are made as shown, where the
connection of the electrical DC power from the motor control PCB,
to the stator windings 47, is through the contacts TP6, TP7, to
contacts 58, 57 on FIG. 3.
[0047] The power supply printed circuit board 22 includes the two
lines power contacts from the line voltage WI, which can be 112-120
Volts AC or 240 Volts AC, to a rectifier G1 to convert the power to
DC, e.g., 115 VAC to 170 VDC, or 240 V AC to 340 VDC. The rectified
power is then transmitted to the PCB of the motor control board
116, via power contacts J6, which then powers the operation of the
motor, and thus the pump, through its microprocessor, utilizing the
data received from the sensors transmitted to the motor control
board via 8-pins connector J7. The signals from the temperature
sensors, or thermistors, are passed on from the thermistors (not
shown in FIGS. 8-9B) to provide data to the DSP and the CPU through
the connection J7, controlling the frequency of the power output to
the motor stator windings 58.
[0048] The commutation is effected in a so-called sensorless,
electronic manner, utilizing the operational amplifier (OPAMP) and
the comparator 59 forming a part of the PCB system and thereby
allowing the full rectified voltage (e.g., 170V from a 120 VAC
line) to power the pump. The larger ferrite magnet and the somewhat
resultingly larger diameter of the stator 148 allow for the
additional space required by U.S. regulation to handle the higher
voltage and result in a more efficient system, as compared to
previously available pump motors and their controls. The thicker
ferrite magnet, as compared to the use of magnets containing an
environmentally problematic rare earth metal, such as Neodymium. is
less likely to be demagnetized at higher power outputs as well as
at higher temperatures, and therefore can be used under more
extreme conditions of operation, and for liquids that may be highly
corrosive, such as salt water. The ceramic ferrite magnet is highly
resistant to chemical corrosion.
[0049] Further by utilizing the higher voltage, without requiring a
transformer, the motor is allowed to run at a lower temperature
than with the lower voltage power. The higher voltage allows for
the lower current flow through the stator windings, and thus
reduces heat loss and raises efficiency.
[0050] The ferrite magnet on the rotor, by avoiding the use of a
back iron usually required when using rare earth magnets, avoids
the corrosion of a back iron. A back iron 154, as shown in FIG. 4a,
for example, increases the weight of the rotor, making it more
difficult to balance the rotor, although the additional copper wire
turns required to compensate for the lower magnetic flux of the
ferrite magnet maintains the total weight of the motor. However,
heat losses due to the higher current in the prior pumps are
reduced by operating with a lower current in the present invention.
Although the additional copper wire windings increase heat losses
linearly, due to electrical resistance "R", the effect of the lower
current "I", resulting from the increase in voltage from 12 VDC in
prior pumps to 170 or 240 VDC in the pump of the present invention,
has a geometric effect on power loss as a result of the power loss
equation, heat loss=I.sup.2R. Accordingly, lower heat losses result
in greater efficiency.
[0051] Without the back iron, the stator electromagnets are able to
be easily magnetized sinusoidally, resulting in fewer harmonics as
the polarity is switched, which also contributes to lower power
losses, as well as a reduction in vibration noise, both electrical
and audible. Using a back iron causes the flux through the
permanent magnet to be purely radial and through the stator
electromagnet to be purely radial, resulting in rapid change from
positive to negative polarity of the stator as the polarity of the
electricity is varied by the commutator/controller. This results in
a trapezoidal profile which is not as efficient or as quiet, as the
sinusoidal profile provided by the present invention.
[0052] The electrical connections WI to the line voltage on the
power PCB comprise insulation displacement connectors. When
alternating current is converted to DC voltage by the bridge
rectifier and capacitor on the power PCB, the bus direct current
voltage provided to the motor control board is 170 volts DC,
assuming the usual 115-120 V AC house current circuit in the U.S.
The increased bus voltage requires a larger space in the motor
compartment, which is also required by the larger, but less costly,
ferrite magnet; this not only eliminates a transformer, but also
increases efficiency by reducing heat generated from higher current
resistance losses, when operating at low voltages, e.g., about 12V
in prior art motors, requiring higher current flows to provide the
necessary power for the motor.
[0053] The rectification of the 115-120 volt alternating current to
170 volt direct current, is accomplished with well-known systems,
such as a bridge rectifier combined with a capacitor, which is
located on the power supply board 22, located behind the LED screen
17. When operating in a locale using 230-240V AC current, direct
current of 340V DC is obtained, thus requiring changing primarily
the capacitors to avoid damage at the higher voltages. The
resulting direct current is passed via a two-pin connector to the
motor control board 116. The data signal input from the thermal
sensors, or thermistors, is also located on the motor control board
22, which then transmits the data signal to the motor control board
116, via an eight-pin connector utilizing low voltage signal
connections.
[0054] The direct current in the motor control board 116 is acted
upon by an IGBT power module, which includes a 3 phase inverter U1,
to form the artificial, sinusoidally varying direct voltage fed to
the motor to control its speed, together with the microcontroller
U2, on the motor controller board 116. The frequency of the voltage
is then varied using the operational amplifier ("OP AMP") U6, a
comparator U4 and a resonator Y1, controlled from the
microcontroller U2, acting upon the signal from the thermistor with
respect to determining whether to increase or decrease the
oscillating frequency of the current as required to meet the fluid
flow demands of the system. The various above listed electronic
components, the operational amplifier ("OP AMP") and the comparator
are readily available commercially, from Microchip, Diodes,
Fairchild, and Texas Instruments, for example. It is understood
that increasing the frequency of the sinusoidal current
oscillations will increase the pump speed and thus the liquid flow
rate.
[0055] The comparator, which may be a form of OPAMP, but is
preferably a separate unit on the motor controller 116 PCB, acts as
a commutator so as to continuously determine the angular position
of the rotor poles relative to the stator, based upon the back EMF
of the system, i.e., as generated by the rotor permanent magnets on
the non-electrified stator windings. One example of a suitable Op
Amp is the Texas Instruments LMV3441 type of unit.
[0056] A ceramic magnet is generally formed of ferromagnetic
ceramic compounds derived from iron oxides such as hematite
(Fe.sub.2O.sub.3) or magnetite (Fe.sub.3O.sub.4), and preferably
includes oxides of other metals, such as strontium or barium. These
ceramic materials are preferably not electrically conductive, i.e.,
have a high resistivity, and are highly resistant to further
oxidative corrosion.
[0057] To obtain the necessary fine control over motor speed and
acceleration and efficiency, the present system also includes a
digital microprocessor, or microcontroller, on each of the motor
control and power control PCB's. The motor control PCB responds to
the signals from, e.g., the thermistor sensor, as passed from the
Power board microcontroller, in accordance with the installed
program that a particular fluid system is intended to operate. The
desired program can be selected using the three buttons SW1, SW2,
SW3, on the front face of the power Supply Board, which are
connected to the microcontroller board on the Power board. By
following the selected program in the microcontroller, the speed of
the motor rotor is selected to match the pump impeller speed
required to meet the need for cooling or heating fluid flow in the
system. The thermistors are connected to the microcontroller so as
to provide the needed data for the microcontroller to maintain the
necessary speed of the motor as system temperature conditions may
change.
[0058] The higher bus voltage permits the use of a graphical liquid
crystal display (LCD) with backlight, allowing more information to
be provided on the screen to an operator, as compared with the
prior art numerical LED displays.
[0059] Again referring to the drawings, the stator provides six
slots 148 for the electrical wire windings 47. Power is provided to
the electrical windings through the connection links 57, 58. The
rotor, which has four poles (two positive and two negative poles)
rotates concentrically within the stator core and, in one
embodiment, includes a permanent strontium ferrite magnet (64),
surrounded by a plastic coating. The rotor 60 is locked, or keyed,
by keys (62) to the rotor shaft 66, so as to rotate without
slippage when the current is provided to the stator and the stator
polarity is sinusoidally varied. The motor control PCB 16 contains
software, including firmware, and is held within a portion of the
electronics enclosure 12.
[0060] The motor control PCB controls the speed of the rotor 60,
and thus the pump impeller, acting upon temperature data received
from the thermistors through the connection 25; the temperature
data is initially passed through the sensor and power control
microprocessor, which then passes the transformed data, through the
8-pins connector J1 to the motor control board. The motor control
board microprocessor sends instructions to vary the electrical
frequency of the sinusoidal curve to operate the pump in accordance
with its software to maintain the fluid flow from the pump at the
value required to maintain the desired flow system temperature, as
measured by the thermistors. By combining both an OP AMP and a
comparator, the error-inducing effect of electrical noise is
reduced and the sinusoidal curve smoothed so that there is less
vibration and a greater efficiency in the operation of the pump.
The software provided on the overall system controls the current
polarity in a sinusoidal curve, as opposed to a trapezoidal drive
curve primarily used by the prior art using rare earth metal
permanent magnet rotor and a 12 V DC input.
[0061] In FIG. 8a, is shown an example of an overall circuit
diagram for the motor control PCB 116, showing the
interrelationships among the OPAMP, the Comparator and the
Microcontroller, that renders the system especially efficient and
durable. Referring to FIGS. 8 and 8a, the electronic elements are
identified in Table 1, below. Referring to FIGS. 9a and 9b, the
electronic elements are identified in Table 2, below.
TABLE-US-00001 TABLE 1 QTY REFDES DESCRIPTION 1 C1 CAP, 2200 PF 200
VAC CER RADIAL, Y2 SAFTY, DIA9 MM, 10 MM LEADS 10 C10, C23, C14,
C15, C16, C17, CAP CER 1.0 UF 15 V X7R 10% 0603 C18, C19, C20, C21
1 C2 CAP ELECTROLITIC RAD, 18 .times. 40 MM, 220 UF, 250 V, 20% 5
C25, C27, C28, C30, C46 CAP CERAMIC 100 PF 50 V 0603 SMD 2 C3, C12
CAP TANTALUM 47 UF 10 V 20% SMD 1 C33 CAP METAL POLY 7.9 .times. 6
MM, .1 UF, 250 V, 10% 6 C4, C5, C23, C24, C26, C29 CAP CERAMIC
CHIP, 0603, .001 UF, 50 V, 10% 3 C6, C31, C32 CAP, 1 UF 10 V
CERAMIC X7R 0603, 10% 3 C7, C11, C22 CAP ELECTROLITIC, SMT 6.3 MM,
100 UF, 25 V, 20% 1 C8 CAP CERAMIC CHIP, 0603, .01 UF, 50 V, 10% 1
C9 CAP CERAMIC CHIP, 0603, 10.0 UF, 10 V, 20%, X5R 1 D10 RECTIFIER
DIODE, 5 MA, 100 V, 1 A, TR = 50 NSEC 1 D11 ZENER DIODE, 5 MB, 200
V, 3 W 1 D4 ZENER DIODE, SOD323, 9.1 V, 200 MW 2 D5, D13 SWITCHING
DIODE, SOD323, 75 V 1 D9 RECTIFIER DIODE, SUPER FAST, 400 V, 1 A 1
F1 FUSE, SLO-BLO, 2.0 A, 125 V, SMD 1 G1 BRIDGE RECTIFIER, GBU, 4
A, 400 V 1 J1 2 .times. 4 8 PIN .100'' SMD, REAR ENTRY, ALIGNMENT
PINS 1 J2 1 PIN, POWER, SOCKET, .200' 1 J4 TERM BLOCK HDR 3.81 MM 2
POS PCB 1 J7 CONN FPC/FFC 18 POS .5 MM HORZ SMD, CONTACTS TOP 2 L1,
L2 FERRITE CHIP 2 AMP, 220 OHMS @ 100 MHZ 1 Q1 NPN TRANSISTOR,
DARLINGTON, SOT23, 40 V, 500 MA 1 R1 RESISTOR CHIP, TKF, 2010, 47,
5% 1 R16 RESISTOR CHIP, TKF, 0805, 6.8, 5%, 100 PPM 3 R17, R18, R19
RES 10K OHM 1/10 W 5% 0603 SMD 5 R2, R3, R6, R7, R8 RES 4.7K OHM
1/10 W 5% 0603 SMD 3 SW1, SW2, SW3 SWITCH TACT 5PST 7.0 MM HEIGHT,
SMD 1 U1 SWITCHING REGULATOR, 265 VAC; 7 W 1 U2 MICROPROCESSOR, 28
PIN SSOP 1 U3 IC, DUAL DIGITAL ISOLATORS, 1 MBPS 1 U7 VOLTAGE
REGULATOR, 3.3 VOLT, 4 PIN, SOT-223 1 U8 VOLTAGE REGULATOR, 5.0
VOLT, 4 PIN, SOT-223 1 W1 2 WIRES, BLACK & WHITE W/GROMMET 1 X1
TRANSFORMER, 5 W PS, 85-265 VAC, 60/50 HZ, 18 VDC, 7 W 1 -- PRINTED
WIRING BOARD, 1 1 ELECTRONIC ENCLOSURE, LCD 1 2 LCD PANEL 2 4 SCREW
#4 .times. 1/4''
TABLE-US-00002 TABLE 2 QTY REFDES DESCRIPTION 1 C1 CAP, 2200 PF 200
VAC CER RADIAL, Y2 SAFTY, DIA 9 MM, 10 MM LEADS 10 C10, C13, C14,
CAP CER 1.0 UF 16 VX7R 10% 0603 C15, C16, C17, C18, C19, C20, C21 1
C2 CAP ELECTROLITIC RAD, 18 .times. 40 MM, 220 UF, 250 V, 20% 5
C25, C27, C28, CAP CERAMIC 100 PF 50 V 0603 SMD C30, C46 2 C2, C12
CAP TANTALUM 47 UF 10 V 20% SMD 1 C33 CAP METAL POLY, 7.9 .times. 6
MM, 1 UF, 250 V, 10% 6 C4, C5, C23, CAP CERAMIC CHIP, 0603, .001
UF, 50 V, 10% C24, C26, C29 3 C6, C31, C32 CAP .1 UF 10 V CERAMIC
X7R 0603, 10% 3 C7, C11, C22 CAP ELECTROLITIC, SMT 6.3 MM, 100 UF,
25 V, 20% 1 C8 CAP CERAMIC CHIP, 0603, .01 UF, 50 V, 10% 1 C9 CAP
CERAMIC CHIP, 0603, 10.0 UF, 10 V, 20% XSR 1 D10 RECTIFIER DIODE,
SMA, 100 V, IA, TR = 50 NSEC 1 D11 ZENER DIODE, 5 MB, 200 V, 3 W 1
D4 ZENER DIODE, SOD323, 9.1 V, 200 MW 2 D5, D13 SWITCHING DIODE,
SOD323, 25 V 1 D9 RECTIFIER DIODE, SUPER FAST, 400 V, 1 A 1 F1
FUSE, SLO-BLO, 2.0 A, 125 V, SMD 1 G1 BRIDGE RECTIFIER, BGU, 4 A,
400 V 1 J1 2 .times. 4 9 PIN .100'' SMD, REAR ENTRY, ALIGNMENT PINS
1 J2 2 PIN, POWER SOCKET, .200'' 1 J4 TERM BLOCK HDR 3.81 MM 3POS
PCB 1 J7 CONN FPC/FFC 18POS .5 MM HORZ SMD, CONTACTS TOP 2 L1, L2
FERRITE CHIP 2 AMP, 220 OHMS @ 100 MHZ 1 Q1 NPN TRANSISTOR,
DARLINGTON, SOT23, 40 V, 500 MA I R1 RESISTOR CHIP, TKF, 2010, 47,
5 1 R16 RESISTOR CHIP, TKF, 0805, 6.8, 5%, 100 PPM % 3 R17, R18,
R19 RES 10K 0HM 1/10 W 5% 0603 SMD 5 R2, R3, R6, R7, RES 4.7K OHM
1/10 W 5% 0603 SMD R8 3 R4, R5, R11 RESISTOR CHIP, 10 K, 1%, 1/10 W
603 1 RT1 THERMISTOR, NTC, 10 OHM, 2.0 AMP 3 SW1, SW2, SWITCH TACT
SPST 7.0 MM HEIGHT, SMD SW3 1 U1 SWITCHING REGULATOR, 265 VAC; 7 W
1 U2 MICROPROCESSOR, 28 PIN SSOP 1 U3 IC, DUAL DIGITAL ISOLATORS, 1
MBPS 1 U7 VOLTAGE REGULATOR, 3.3 VOLT, 4 PIN, SOT-223 1 U8 VOLTAGE
REGULATOR, 5.0 VOLT, 4 PIN, SOT-223 1 W1 2 WIRES, BLACK & WHITE
W/GROMMET 1 X1 TRANSFORMER, SWPS, 85-265 VAC, 60/50 HZ, 18 VDC, 7 W
1 -- PRINTED WIRING BOARD 1 1 ELECTRONIC ENCLOSURE, LCD 1 2 LCD
PANEL 2 4 SCREW, #4 .times. 1/4'' LG, PAN HD PHILLIPS, STEEL ZINC
PLATED, HI-LO THREAD FOR PLASTIC
[0062] The controller 16 is preprogrammed to include the algorithms
expressed by the flow charts of FIGS. 10-15.
[0063] Referring to the flow chart of FIG. 10 and the flow system
diagram of FIG. 16a, these describe the operation and show the flow
system for a closed loop, Delta T heating system, with a pre-purge
ramp-up feature, utilizing a single operating pump 120 and a boiler
type water heater 200. The system includes a supply temperature
sensor 210 and a return temperature sensor 212, measuring the
temperature of the liquid in the line leaving the boiler heater and
the line returning to the boiler heater, respectively. There are
multiple loop heating system lines 240, 250, 260, coming off from
and returning to the main supply and return lines 220, 230; each
loop 240, 250, 260 is controlled by a mechanical valve 241, 251,
261, respectively. The valves, however, are not controlled from the
circulator system, but rather are independently controlled, either
manually or by some other electronic or thermostatic system.
[0064] The operation of the system of FIG. 16a, is shown in the
flow chart of FIG. 10, S1 being the supply temperature, sensed by
the thermistor 210, and S2 being the return temperature sensed by
the thermistor 212. As shown, when the pump 120 is started, the
control algorithm determines whether the start-up Delta T meets the
required Delta T, as preset in the algorithm. If the Delta T is too
small, the pump will be shut down and the temperatures monitored
until the Delta T values are reached. In this case, each of the
temperatures is set by the operator and, in this manner, the Delta
T is maintained without running the risk of having the supply fluid
be too low, and the return liquid be so low as to create a problem
in the boiler.
[0065] The pump is programmed to start at a minimal speed and
gradually increased, or ramped up; over the period of the increase,
the Delta T is continued to be monitored. At the point where the
supply temperature S1, is not greater than a predetermined value,
e.g., 10.degree. F., above the return temperature S2, the pump is
then slowed. Or, if it is less than a desired temperature, e.g.,
180.degree. F., which is usually the default minimum temperature,
the pump is shut down. As shown, the pump algorithm is set so as to
maintain the desired temperature flow and heating pattern without
endangering the boiler. As shown, the safety feature included
within this algorithm requires that the return temperature should
be within the range of 180-230.degree. F.
[0066] FIG. 16b is also a Delta T type operation as in the case of
FIG. 11, but in this case utilizes radiant manifolds and further
includes a separate boiler sensor and an outdoor temperature sensor
for a more nuanced control over the amount of heat required, and to
avoid damage to the boiler. If the boiler thermistor 312 registers
too low a temperature, the by-pass valve 360 is opened, and/or if
the return thermistor 312 reads too low, the pump 300 is slowed
down.
[0067] FIG. 16c is a diagram showing the type of flow system for a
radiant injection heater and is based upon a predetermined set
point temperature, including a boiler return protection option. As
shown in the flow chart of FIG. 14, the set point heat mode
algorithm is selected and a particular temperature is entered. The
controller in the circulator monitors the supply sensor 410
immediately prior to entering the radiation system 401 and also
monitors the boiler protection sensor 412 to ensure that the
desired amount of heating is provided to the radiation system and
that the boiler is protected by avoiding excessively low
temperatures on the boiler return line. This system includes three
pumps where the center pump 420 is the pump being controlled by the
sensors and controllers, the other pumps operating at constant
speed, i.e., 421 and 422. When the center pump 120 is started, it
is initially put through a series of steps to ensure that the
sensors are connected. If S1 is connected and the boiler sensor 412
is connected, the pump rotor speed is set to a minimum speed, as
long as the temperature measured by the boiler sensor is below the
boiler set point temperature. Once the sensor of the line returning
to the boiler reaches a desired set point, and the supply
temperature is at the desired temperature set point for that
sensor, the speed of the motor for pump 120 increases so as to
further increase the temperature. Once the S1 temperature drops
below the set point, the speed of pump 120 again increases to
increase the temperature. If the S1 temperature set point is above
the desired set point temperature, the speed of the controlled pump
120 is reduced until the desired temperature reading is once again
reached. The boiler protection in this case, as noted, is achieved
by reducing the speed of the pump 120 so as to allow more of the
hot liquid pumped through the constant power pump 422 to be
directly returned to the boiler via bypass line 450, as the pump
120 will be operating at a lower level than the constant power
speed of pump 422. In this way, the fluid returning to the boiler
is maintained at a sufficiently high temperature to prevent boiler
shock and to prevent condensation of the flue gas exhaust.
[0068] The flow diagram of FIG. 16d includes a shunt bypass method
of protecting the boiler from excessively low return temperatures.
Such return temperatures are, for example, often met with regard to
large venues that are not used on a regular daily basis. For
example, large entertainment halls or houses of worship. In the
case of FIG. 16d, the boiler protection mode operation of the flow
chart of FIG. 15 is useful. This algorithm provides that the
initial determination by the system is whether the boiler return
sensor 512 is connected and operating and, if so, the pump 120
monitors that sensor. To the extent that the sensor indicates that
the temperature is below the boiler protection set point, the pump
rotor 120 is set to maximum rpm in order to return a substantial
proportion of the hot water back to the boiler to intermix with the
returning water from the heating system, thereby slowing down the
heating of the venue but also protecting the boiler. Once the
temperature has reached above the sensitive boiler protection set
point, the pump 120 speed is reduced or turned off, and the
remaining two pumps continue to bring hot water to the radiation
manifold and then back to the boiler. The boiler return sensor 512
continues to monitor that temperature to ensure that the water is
not too low in temperature to prevent boiler shock or to, at worst,
cause condensation of the flue exhaust gas.
[0069] The system of FIG. 14 is a fan-blown air, fixed temperature
system and can be used for heating or cooling, dependent upon
whether it is connected to a boiler 506 or a cooling system 705.
The heated or chilled liquid is brought into the coils of the ducts
through which air is blown, and the heated or chilled air is blown
through the duct system 650. The supply sensor 612 monitors the air
temperature and causes an increased speed of pump 120 for the
liquid into the air duct coils, if the temperature is too low, or
reduces the flow of liquid, once the temperature reaches to above
the desired set point. In this system, an auxiliary pump 621
provides continuing fluid flow of a minimal amount, which is often
necessary to maintain the operation of the system, and the flow
through the heating or cooling ducts can be reduced or eliminated
by operation of the pump 620 or, if the pump is shut down, the
valve 630 can be closed, thereby shutting off that system
completely. FIG. 16e is operated in accordance with the flow chart
of FIG. 15 in the cooling mode.
* * * * *