U.S. patent application number 09/785465 was filed with the patent office on 2001-08-30 for controller of elevator.
Invention is credited to Araki, Hiroshi, Kobayashi, Kazuyuki, Suga, Ikuro, Tajima, Shinobu.
Application Number | 20010017239 09/785465 |
Document ID | / |
Family ID | 18573876 |
Filed Date | 2001-08-30 |
United States Patent
Application |
20010017239 |
Kind Code |
A1 |
Tajima, Shinobu ; et
al. |
August 30, 2001 |
Controller of elevator
Abstract
This invention provides a controller of an elevator capable of
performing stable speed control by using a cheap power accumulating
device of a low capacity even at a discharging control time.
Therefore, the controller has a converter 2, an inverter 4, a power
accumulating device 11 arranged between DC buses 3, a
charging-discharging control circuit 15 for controlling charging
and discharging operations of the power accumulating device, a
power failure detector 22, a current measuring instrument 23 and a
voltage measuring instrument 24 for respectively detecting an
output current and an output voltage of the inverter, a car load
measuring instrument 25, an encoder 20, and a speed control circuit
21A for controlling an operation of the inverter. The speed control
circuit 21A calculates output power of the inverter, and calculates
discharging ability power of the power accumulating device on the
basis of a measuring value of charging and discharging states. The
speed control circuit 21A also calculates a limit power maximum
value given by a sum of the discharging ability power and limit
power of an AC power source, and changes speed commands on the
basis of comparison of the output power of the inverter and the
limit power maximum value.
Inventors: |
Tajima, Shinobu; (Tokyo,
JP) ; Araki, Hiroshi; (Tokyo, JP) ; Suga,
Ikuro; (Tokyo, JP) ; Kobayashi, Kazuyuki;
(Tokyo, JP) |
Correspondence
Address: |
LEYDIG VOIT & MAYER, LTD
700 THIRTEENTH ST. NW
SUITE 300
WASHINGTON
DC
20005-3960
US
|
Family ID: |
18573876 |
Appl. No.: |
09/785465 |
Filed: |
February 20, 2001 |
Current U.S.
Class: |
187/290 |
Current CPC
Class: |
B66B 1/30 20130101; B66B
1/285 20130101; H02J 7/34 20130101 |
Class at
Publication: |
187/290 |
International
Class: |
B66B 001/06; H02J
009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 28, 2000 |
JP |
2000-052346 |
Claims
What is claimed is:
1. A controller of an elevator comprising: a converter for
rectifying AC power from an AC power source and converting the AC
power to DC power; an inverter for converting the DC power
outputted from said converter to AC power of a variable voltage and
a variable frequency and driving an electric motor and operating
the elevator; a power accumulating device arranged between DC buses
between said converter and said inverter, and accumulating DC power
from the DC buses at a regenerative operation time of the elevator,
and supplying the accumulated DC power to the DC buses at a power
running operation time; a charging-discharging control device for
controlling charging and discharging operations of said power
accumulating device with respect to said DC buses;
charging-discharging state measuring means for measuring at least
one of a temperature, charging and discharging currents, and
charging and discharging voltages of said power accumulating
device; current detecting means for detecting an output current of
said inverter; voltage detecting means for detecting an output
voltage of said inverter; speed detecting means for detecting a
speed of said elevator; and speed control means for controlling an
operation of said inverter to perform speed control based on speed
commands of the elevator and a detecting value from said speed
detecting means; the controller being characterized in that said
speed control means calculates output power of the inverter on the
basis of a detected current value of said current detecting means
and a detected voltage value of said voltage detecting means, and
calculates discharging ability power of said power accumulating
device on the basis of a measuring value of said
charging-discharging state measuring means, and calculates a
limited power maximum value given by a sum of the discharging
ability power and limited power of said AC power source, and
changes speed commands on the basis of comparison of the output
power of said inverter and said limited power maximum value.
2. A controller of an elevator according to claim 1, wherein said
speed control means has a table set with a limited discharging
current with respect to a discharging current and a discharging
voltage, and calculates the limited discharging current from said
table on the basis of measuring values of the discharging current
and the discharging voltage from said charging-discharging state
measuring means, and calculates the discharging ability power of
said power accumulating device from the calculated limited
discharging current and the measuring value of the discharging
voltage.
3. A controller of an elevator according to claim 1, wherein said
speed control means has a table set with a limited discharging
current with respect to a charging degree as a value obtained by
normalizing and accumulating a product of a charging-discharging
current and a charging-discharging voltage by a capacity with a
full charging state of said power accumulating device as 100%, and
the limited discharging current is calculated from said table on
the basis of the charging degree obtained on the basis of measuring
values of the discharging current and the discharging voltage from
said charging-discharging state measuring means, and the
discharging ability power of said power accumulating device is
calculated from the calculated limited discharging current and the
measuring value of the discharging voltage.
4. A controller of an elevator according to claim 3, wherein said
speed control means has plural tables according to the temperature
of said power accumulating device, and selects a table according to
a temperature measuring value provided by said charging-discharging
state measuring means.
5. A controller of an elevator according to claim 1, wherein said
speed control means has a table setting a speed pattern according
to a load state, and calculates the speed pattern from said table
on the basis of a car load measuring value measured by car load
measuring means and generates speed commands according to the
calculated speed pattern when it is judged on the basis of a
measuring value provided by said charging-discharging state
measuring means that said power accumulating device is broken.
6. A controller of an elevator according to claim 1, wherein said
speed control means has a table set with a maximum speed command
value with respect to a car load and the discharging ability power
of said power accumulating device, and calculates the discharging
ability power of said power accumulating device on the basis of a
measuring value of said charging-discharging state measuring means,
and calculates maximum speed commands from said table on the basis
of a car load measuring value measured by car load measuring means
and the calculated discharging ability power, and changes speed
commands on the basis of comparison of the speed commands and the
maximum speed commands.
7. A controller of an elevator according to claim 5, wherein said
speed control means has plural speed pattern tables corresponding
to the car load and the discharging ability power of said power
accumulating device, and calculates the discharging ability power
of said power accumulating device on the basis of the measuring
value of said charging-discharging state measuring means, and
selects said tables on the basis of the car load measuring value
measured by said car load measuring means, and performs speed
control according to a selected speed pattern.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a controller of an elevator of an
energy saving type to which a secondary battery is applied.
[0003] 2. Description of the Related Art
[0004] FIG. 13 is a view showing the basic construction of a
controller for controlling the operation of an elevator by applying
a conventional secondary battery thereto.
[0005] In FIG. 13, reference numerals 1 and 2 respectively
designate a three-phase AC power source and a converter constructed
by a diode, etc. and converting AC power outputted from the
three-phase AC power source 1 to DC power. The DC power converted
by the converter 2 is supplied to a DC bus 3. The operation of an
inverter 4 is controlled by a speed controller for controlling a
speed position of the elevator and described later. A direct
current supplied through the DC bus 3 is converted to an
alternating current of predetermined desirable variable voltage and
variable frequency and an AC motor 5 is driven so that a hoisting
machine 6 of the elevator directly connected to the AC motor 5 is
rotated. Thus, a rope 7 wound around the hoisting machine 6
controls elevating and lowering operations of a car 8 and a
counterweight 9 connected to both ends of this rope 7 and
passengers within the car 8 are moved to a predetermined stage
floor.
[0006] Here, weights of the car 8 and the counterweight 9 are
designed such that these weights are approximately equal to each
other when passengers half a number limit ride in the car 8.
Namely, when the car 8 is elevated and lowered with no load, a
power running operation is performed at a lowering time of the car
8 and a regenerative operation is performed at a elevating time of
the car 8. Conversely, when the car 8 is lowered in the number
limit riding, the regenerative operation is performed at the
lowering time of the car 8 and the power running operation is
performed at the elevating time of the car 8.
[0007] An elevator control circuit 10 is constructed by a
microcomputer, etc., and manages and controls an entire operation
of the elevator. A power accumulating device 11 is arranged between
DC buses 3 and accumulates power at the regenerative operation time
of the elevator, and supplies the accumulated power to the inverter
4 together with the converter 2 at the power running operation
time. The power accumulating device 11 is constructed by a
secondary battery 12 and a DC-DC converter 13 for controlling
charging and discharging operations of this secondary battery
12.
[0008] Here, the DC-DC converter 13 has a voltage lowering type
chopper circuit and a voltage raising type chopper circuit. The
voltage lowering type chopper circuit is constructed by a reactor
13a, a gate 13b for charging current control connected in series to
this reactor 13a, and a diode 13c connected in reverse parallel to
a gate 13d for discharging current control described later. The
voltage raising type chopper circuit is constructed by the reactor
13a, the gate 13d for discharging current control connected in
series to this reactor 13a, and a diode 13e connected in reverse
parallel to the above gate 13b for charging current control.
Operations of the gate 13b for charging current control and the
gate 13d for discharging current control are controlled by a
charging-discharging control circuit 15 on the basis of a measuring
value from a charging-discharging state measuring device 14 for
measuring charging and discharging states of the power accumulating
device 11 and a measuring value from a voltage measuring instrument
18. A current measuring instrument arranged between the secondary
battery 12 and the DC-DC converter 13 is used as the
charging-discharging state measuring device 14 in this conventional
example.
[0009] A gate 16 for regenerative current control and a
regenerative resistor 17 are arranged between DC buses 3. The
voltage measuring instrument 18 measures the voltage of a DC bus 3.
A regenerative control circuit 19 is operated on the basis of
regenerative control commands from a speed control circuit
described later. The gate 16 for regenerative current control is
constructed such that an ON pulse width is controlled on the basis
of control of the regenerative control circuit 19 when a measuring
voltage provided by the voltage measuring instrument 17 is equal to
or greater than a predetermined value at the regenerative operation
time. Regenerated power is discharged in the regenerative resistor
17 and is converted to thermal energy and is consumed.
[0010] An encoder 20 is directly connected to the hoisting machine
6. The speed control circuit 21 controls a position and a speed of
the elevator by controlling an output voltage and an output
frequency of the inverter 4 on the basis of speed commands and a
speed feedback output from the encoder 22 based on commands from
the elevator control circuit 10.
[0011] An operation of the controller having the above construction
will next be explained.
[0012] At a power running operation time of the elevator, power is
supplied to the inverter 4 from both the three-phase AC power
source 1 and the power accumulating device 11. The power
accumulating device 11 is constructed by the secondary battery 12
and the DC-DC converter 13, and an operation of this power
accumulating device 11 is controlled by the charging-discharging
control circuit 15. In general, the number of secondary batteries
12 is reduced as much as possible and an output voltage of each
secondary battery 12 is lower than the voltage of the DC bus 3 so
as to make the controller compact and cheaply construct the
controller. The voltage of the DC bus 3 is basically controlled
near a voltage provided by rectifying a three-phase AC of the
three-phase AC power source 1. Accordingly, it is necessary to
lower the bus voltage of the DC bus 3 at a charging time of the
secondary battery 12 and raise the bus voltage of the DC bus 3 at a
discharging time of the secondary battery 12. Therefore, the DC-DC
converter 13 is adopted. Operations of the gate 13b for charging
current control and the gate 13d for discharging current control in
this DC-DC converter 13 are controlled by the charging-discharging
control circuit 15.
[0013] FIGS. 14 and 15 are flow charts showing controls of the
charging-discharging control circuit 15 at its discharging and
charging times.
[0014] The control of the charging-discharging control circuit 15
at the discharging time shown in FIG. 14 will first be
explained.
[0015] A current control minor loop, etc. are constructed in
voltage control of a control system and the control operation may
be more stably performed. However, for simplicity, the control of
the charging-discharging control circuit 15 is here explained by a
control system using the bus voltage.
[0016] First, the bus voltage of the DC bus 3 is measured by the
voltage measuring instrument 17 (step S11). The
charging-discharging control circuit 15 compares this measuring
voltage with a predetermined desirable voltage set value and judges
whether the measuring voltage exceeds the voltage set value or not
(step S12). If no measuring voltage exceeds the set value, the
charging-discharging control circuit 15 next judges whether the
measuring value of a discharging current of the secondary battery
12 provided by the charging-discharging state measuring device 14
exceeds a predetermined value or not (step S13).
[0017] When the measuring voltage exceeds the set value by these
judgments, or when the measuring value of the discharging current
of the secondary battery 12 exceeds the predetermined value even if
no measuring voltage exceeds the set value, an adjusting time DT is
subtracted from the present ON time to shorten an ON pulse width of
the gate 13d for discharging current control and a new gate ON time
is calculated (step S14).
[0018] In contrast to this, when it is judged in the above step S13
that no measuring value of the discharging current of the secondary
battery 12 provided by the measuring device 14 exceeds the
predetermined value, a new gate ON time is calculated by adding the
adjusting time DT to the present ON time so as to lengthen the ON
pulse width of the gate 13d for discharging current control (step
S15). Thus, ON control of the gate 13d for discharging current
control is performed on the basis of the calculated gate ON time,
and the calculated gate ON time is stored to a built-in memory as
the present ON time (step S16).
[0019] Thus, a more electric current flows from the secondary
battery 12 by lengthening the ON pulse width of the gate 13d for
discharging current control. As a result, supply power is increased
and the bus voltage of the DC bus 3 is increased by the power
supply. When the power running operation is considered, the
elevator requires the power supply and this power is supplied by
discharging from the above secondary battery 12 and power supply
from the three-phase AC power source 1. When the bus voltage is
controlled such that this bus voltage is higher than an output
voltage of the converter 2 supplied from the three-phase AC power
source 1, all power is supplied from the secondary battery 12.
However, the controller is designed such that all power is not
supplied from the secondary battery 12, but is supplied from the
secondary battery 12 and the three-phase AC power source 1 in a
suitable ratio so as to cheaply construct the power accumulating
device 11.
[0020] Namely, in FIG. 14, the measuring value of the discharging
current is compared with a supply allotment corresponding current
(predetermined value). If this measuring value exceeds the
predetermined value, the ON pulse width of the gate 13d for
discharging current control is lengthened and a supply amount is
further increased. In contrast to this, when no measuring value of
the discharging current exceeds the predetermined value, the ON
pulse width of the gate 13d for discharging current control is
shortened and the power supply is clipped. Thus, since power
supplied from the secondary battery 12 is clipped among power
required in the inverter 4, the bus voltage of the DC bus 3 is
reduced so that the power supply from the converter 2 is started.
These operations are performed for a very short time so that a
suitable bus voltage is actually obtained to supply required power
of the elevator. Thus, power can be supplied from the secondary
battery 12 and the three-phase AC power source 1 in a predetermined
desirable ratio.
[0021] The control of the charging-discharging control circuit 15
at the charging time shown in FIG. 15 will next be explained.
[0022] When there is power regeneration from the AC motor 5, the
bus voltage of the DC bus 3 is increased by this regenerated power.
When this voltage is higher than an output voltage of the converter
2, the power supply from the three-phase AC power source 1 is
stopped. When there is no power accumulating device 11 and this
stopping state is continued, the voltage of the DC bus 3 is
increased. Therefore, when a measuring voltage value of the voltage
measuring instrument 17 for detecting the bus voltage of the DC bus
3 reaches a certain predetermined voltage, the regenerative control
circuit 19 is operated and closes the gate 16 for regenerative
current control. Thus, power flows through the regenerative
resistor 17 and the regenerated power is consumed and the elevator
is decelerated by electromagnetic braking effects. However, when
there is the power accumulating device 11, this power is charged to
the power accumulating device 11 by the control of the
charging-discharging control circuit 15 with a voltage equal to or
smaller than a predetermined voltage.
[0023] Namely, as shown in FIG. 15, if the measuring value of the
bus voltage of the DC bus 3 provided by the voltage measuring
instrument 17 exceeds the predetermined voltage, the
charging-discharging control circuit 15 detects that it is a
regenerative state, and increases a charging current to the
secondary battery 12 by lengthening the ON pulse width of the gate
13b for charging current control (step S21.fwdarw.S22.fwdarw.S23).
When the regenerated power from the elevator is reduced in a short
time, the voltage of the DC bus 3 is also correspondingly reduced
and no measuring value of the voltage measuring instrument 17
exceeds the predetermined voltage. Accordingly, the ON pulse width
of the gate 13b for charging current control is shortly controlled
and charging power is also reduced and controlled (step
S21.fwdarw.S22.fwdarw.S24).
[0024] Thus, the bus voltage is controlled in a suitable range and
a charging operation is performed by monitoring the bus voltage of
the DC bus 3 and controlling the charging power. Further, energy is
saved by accumulating and re-utilizing power conventionally
consumed in the regenerated power. When no power of a charger is
consumed for certain reasons such as a breakdown, etc., the above
regenerative control circuit 19 is operated as a backup and the
regenerated power is consumed by a resistor so that the elevator is
suitably decelerated. In a general elevator for housing, the
regenerated power is about 2 KVA and is about 4 KVA at its maximum
decelerating value although this regenerated power is different in
accordance with a capacity of the elevator, etc.
[0025] The regenerative control circuit 19 monitors the voltage of
the DC bus 3. If this voltage is equal to or greater than a
predetermined value, the ON pulse width of the gate 16 for
regenerative current control is controlled by the regenerative
control circuit 19 so as to discharge the above power in the
regenerative resistor 17 so that the regenerated power flows
through the regenerative resistor 17. There are various kinds of
systems for controlling this pulse width, but the pulse width is
simply controlled in accordance with the following formula. Namely,
when the voltage of the DC bus 3 for starting turning-on of the
gate 16 for regenerative current control is set to VR, a flowing
current IR can be simply calculated by turning-on (closing) a
circuit since a resistance value of the regenerative resistor 17 is
already known. Further, maximum power to be flowed is already
known. Therefore, if this maximum power (VA) is set to WR, it is
sufficient to generate an ON pulse of duty of WR/(VR.times.IR)
while the DC bus voltage is monitored. However, an object of this
construction is to consume all regenerated power in the
regenerative resistor 17.
[0026] However, in the above conventional controller of the
elevator, it is necessary to stack the secondary battery 12 of a
large capacity able to charge the regenerated power in the power
accumulating device 11 in all conditions in which a temperature and
a charging degree of the power accumulating device 11, i.e., a full
charging state of the power accumulating device 11 are set to
references and a product of a charging-discharging current by a
charging-discharging voltage is normalized and accumulated in a
capacity, and a SOC (State Of Charge) is obtained as this
normalized and accumulated value, etc. Therefore, an expensive and
large-sized power accumulating device 11 is required.
SUMMARY OF THE INVENTION
[0027] To solve the above problems, an object of this invention is
to provide a controller of an elevator capable of performing stable
speed control by using a cheap power accumulating device of a low
capacity even at a discharging control time.
[0028] To achieve this object, a controller of an elevator in this
invention comprises a converter for rectifying AC power from an AC
power source and converting the AC power to DC power; an inverter
for converting the DC power outputted from the converter to AC
power of a variable voltage and a variable frequency and driving an
electric motor and operating the elevator; a power accumulating
device arranged between DC buses between the converter and the
inverter, and accumulating DC power from the DC buses at a
regenerative operation time of the elevator, and supplying the
accumulated DC power to the DC buses at a power running operation
time; a charging-discharging control device for controlling
charging and discharging operations of the power accumulating
device with respect to the DC buses; charging-discharging state
measuring means for measuring at least one of a temperature,
charging and discharging currents, and charging and discharging
voltages of the power accumulating device; current detecting means
for detecting an output current of the inverter; voltage detecting
means for detecting an output voltage of the inverter; speed
detecting means for detecting a speed of the elevator; and speed
control means for controlling an operation of the inverter to
perform speed control based on speed commands of the elevator and a
detecting value from the speed detecting means; the controller
being characterized in that the speed control means calculates
output power of the inverter on the basis of a detected current
value of the current detecting means and a detected voltage value
of the voltage detecting means, and calculates discharging ability
power of the power accumulating device on the basis of a measuring
value of the charging-discharging state measuring means, and
calculates a limited power maximum value given by a sum of the
discharging ability power and limited power of the AC power source,
and changes speed commands on the basis of comparison of the output
power of the inverter and the limited power maximum value.
[0029] Further, the speed control means has a table set with a
limited discharging current with respect to a discharging current
and a discharging voltage, and calculates the limited discharging
current from the table on the basis of measuring values of the
discharging current and the discharging voltage from the
charging-discharging state measuring means, and calculates the
discharging ability power of the power accumulating device from the
calculated limited discharging current and the measuring value of
the discharging voltage.
[0030] Further, the speed control means has a table set with a
limited discharging current with respect to a charging degree as a
value obtained by normalizing and accumulating a product of a
charging-discharging current and a charging-discharging voltage by
a capacity with a full charging state of the power accumulating
device as 100%, and the limited discharging current is calculated
from the table on the basis of the charging degree obtained on the
basis of measuring values of the discharging current and the
discharging voltage from the charging-discharging state measuring
means, and the discharging ability power of the power accumulating
device is calculated from the calculated limited discharging
current and the measuring value of the discharging voltage.
[0031] Further, the speed control means has plural tables according
to the temperature of the power accumulating device, and selects a
table according to a temperature measuring value provided by the
charging-discharging state measuring means.
[0032] Further, the speed control means has a table setting a speed
pattern according to a load state, and calculates the speed pattern
from the table on the basis of a car load measuring value measured
by car load measuring means and generates speed commands according
to the calculated speed pattern when it is judged on the basis of a
measuring value provided by the charging-discharging state
measuring means that the power accumulating device is broken.
[0033] Further, the speed control means has a table set with a
maximum speed command value with respect to a car load and the
discharging ability power of the power accumulating device, and
calculates the discharging ability power of the power accumulating
device on the basis of a measuring value of the
charging-discharging state measuring means, and calculates maximum
speed commands from the table on the basis of a car load measuring
value measured by car load measuring means and the calculated
discharging ability power, and changes speed commands on the basis
of comparison of the speed commands and the maximum speed
commands.
[0034] Further, the speed control means has plural speed pattern
tables corresponding to the car load and the discharging ability
power of the power accumulating device, and calculates the
discharging ability power of the power accumulating device on the
basis of the measuring value of the charging-discharging state
measuring means, and selects the tables on the basis of the car
load measuring value measured by the car load measuring means, and
performs speed control according to a selected speed pattern.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 is a block diagram showing the construction of a
controller of an elevator in this invention.
[0036] FIG. 2 is a view used to explain speed control of the
elevator at a power failure time in this invention and showing a
power waveform at a power running operation time of the elevator
with a time axis as an axis of abscissa.
[0037] FIG. 3 is an explanatory view of a table T1 arranged in a
speed control circuit 21A in an Embodiment mode 1 of this invention
in which a limit discharging current is set with respect to a
discharging current and a discharging voltage.
[0038] FIG. 4 is a flow chart showing control of the speed control
circuit 21A in the Embodiment mode 1 of this invention.
[0039] FIG. 5 is an explanatory view of a table T2 arranged in a
speed control circuit 21A in an Embodiment mode 2 of this invention
in which a limit discharging current is set with respect to a
charging degree SOC.
[0040] FIG. 6 is an explanatory view of tables T2a, T2b, T2c,
--arranged in a speed control circuit 21A in an Embodiment mode 3
of this invention in which a limit discharging current is set with
respect to plural charging degree SOCs in accordance with
temperature.
[0041] FIG. 7 is an explanatory view of a table T3 arranged in a
speed control circuit 21A in an Embodiment mode 4 of this invention
in which a speed pattern according to a load state is set.
[0042] FIG. 8 is an explanatory view of a table T4 arranged in a
speed control circuit 21A in an Embodiment mode 5 of this invention
in which a maximum command speed is set with respect to a car load
and discharging ability power of a power accumulating device
11.
[0043] FIG. 9 is a flow chart showing control of the speed control
circuit 21A in the Embodiment mode 5 of this invention.
[0044] FIG. 10 is an explanatory view of a table T5 arranged in a
speed control circuit 21A in an Embodiment mode 6 of this invention
in which a command speed is selected in accordance with discharging
ability power and a load measuring value and is set in accordance
with the number of timer interruption times.
[0045] FIG. 11 is an explanatory view of a table T6 arranged in the
speed control circuit 21A in the Embodiment mode 6 of this
invention in which a command speed according to the remaining
distance is set.
[0046] FIG. 12 is a flow chart showing control of the speed control
circuit 21A in the Embodiment mode 6 of this invention.
[0047] FIG. 13 is a block diagram showing the construction of a
controller of an elevator in a conventional example.
[0048] FIG. 14 is a flow chart showing the control of a
charging-discharging control circuit 15 shown in FIG. 13 at its
discharging time.
[0049] FIG. 15 is a flow chart showing the control of the
charging-discharging control circuit 15 shown in FIG. 13 at its
charging time.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0050] In this invention, the speed of an elevator is controlled on
the basis of discharging ability power of a power accumulating
device, and the elevator having the power accumulating device of a
long battery life is provided.
[0051] FIG. 1 is a block diagram showing the construction of a
controller of the elevator in this invention. In FIG. 1, the same
portions as the conventional example shown in FIG. 13 are
designated by the same reference numerals and their explanations
are omitted here. New reference numerals 14A and 21A respectively
designate a charging-discharging state measuring device and a speed
control circuit in the present invention. A power failure detector
22 detects a power failure of a three-phase AC power source 1. A
current measuring instrument 23 and a voltage measuring instrument
24 respectively measure an output current and an output voltage of
an inverter 4. A car load measuring instrument 25 is arranged
between the cabin of a car 8 and a bottom portion of a car frame
and measures a car load. The charging-discharging state measuring
device 14A has each of measuring instruments for measuring charging
and discharging currents, charging and discharging voltages and a
temperature of a power accumulating device 11. In the
charging-discharging state measuring device 14A, each of these
measuring values and a charging degree, i.e., a full charging state
of the power accumulating device 11 is set to 100%, and a SOC
(State Of Charge) as a value obtained by normalizing and
accumulating a product of a charging-discharging current and a
charging-discharging voltage by a capacity is outputted to the
speed control circuit 21A. The speed control circuit 21A outputs
speed commands for controlling a speed of the elevator to the
inverter 4 in a range of discharging ability power of the power
accumulating device 11 at a detecting time of the power failure
during running of the elevator on the basis of a power failure
detecting signal from the power failure detector 22 or the voltage
measuring instrument 18, charging and discharging states from the
charging-discharging state measuring device 14A, a speed feedback
signal from an encoder 20, each of measuring values from the
current measuring instrument 22 and the voltage measuring
instrument 23, and a car load measuring value from a car load
measuring instrument.
[0052] FIG. 2 is a view used to explain speed control at a power
failure time in this invention and showing a power waveform at a
power running operation time of the elevator with a time axis as an
axis of abscissa.
[0053] A power waveform as shown in FIG. 2 (refer (a)) is obtained
in the case of full load riding of the elevator and a power running
operation such as a ascending direction operation time. Power
approximately becomes a total of a power amount depending on the
speed of the elevator as shown in FIG. 2 (refer (b)) and a power
amount depending on acceleration and deceleration as shown in FIG.
2 (refer (c)). A power curve becomes a peak (51) during
acceleration near a highest speed, and becomes a constant voltage
(52) at a constant speed, and power is reduced (53) as deceleration
is started. In discharging from the secondary battery 12, a
dischargeable current value is generally limited by a temperature
of the secondary battery 12, a battery voltage at a discharging
time, etc. When a sufficient secondary battery 12 is stacked in all
cases, the secondary battery 12 becomes expensive. Therefore, it is
necessary to limit the discharging from the secondary battery 12 in
a specific condition. Further, when the discharging from the
secondary battery 12 is limited, the discharging current can be
replaced with a three-phase AC current of the three-phase AC power
source 1, but a power feeder is large-sized and contract power is
increased, etc. so that it becomes expensive. Accordingly, in this
invention, the elevator is operated in an allowable power range of
the three-phase AC power source 1 when the discharging current of
the power accumulating device 11 is limited.
[0054] Each of concrete embodiments will next be explained.
[0055] Embodiment Mode 1
[0056] In this Embodiment mode 1, the speed control circuit 21A has
a table T1 in which a limit discharging current is set with respect
to a discharging current and a discharging voltage as shown in FIG.
3. The speed control circuit 21A calculates discharging ability
power of the power accumulating device 11 by using this table T1,
and also calculates a limit power maximum value provided by a sum
of this discharging ability power and limit power of the AC power
source 1. The speed control circuit 21A then changes speed commands
on the basis of the comparison of output power of the inverter 4
and the limit power maximum value.
[0057] FIG. 3 will first be explained. FIG. 3 shows an example of a
table for limiting the discharging current on the basis of a
voltage of the power accumulating device 11 at its discharging
time. In this example, the limit power maximum value is made by
measuring data of charging and discharging states from the
charging-discharging state measuring device 14A and the above table
T1. In this table, the present discharging current is a discharging
current of the secondary battery 12 outputted from the power
accumulating device 11 at present. The discharging voltage of the
secondary battery 12 is measured and the limit current of a voltage
equal to or greater than a voltage in a voltage column is described
in an item of the limit current. For example, there is particularly
no limit current when the present discharging current is equal to
or greater than A1 ampere and the discharging voltage is equal to
or greater than V11 volt. However, when the discharging voltage
lies between V11 volt and V12 volt, the discharging current is
limited to A12 ampere. When the discharging voltage is equal to or
smaller than V12 volt, a table describing discharging inhibition
etc. is used. If the table is set in further detail, more
preferable results are naturally obtained. Since the speed control
is performed in view of these results, a delay is inevitably
caused. Therefore, it is necessary to design the table with a
margin. It is simple to multiply the present voltage by this limit
current and set limit power.
[0058] Control of the speed control circuit 21A in this Embodiment
Mode 1 will next be explained with reference to a flow chart shown
in FIG. 4.
[0059] In FIG. 5, a command speed Vm according to a standard speed
pattern is calculated from a running object position, the present
command speed, the present position of the elevator, etc. during
running of the elevator, and the speed of the elevator is
controlled (step S101). The present output power Wc is then
calculated on the basis of measuring values of an output current
and an output voltage of the inverter 4 from the current measuring
instrument 23 and the voltage measuring instrument 24 (step
S102).
[0060] Thereafter, discharging ability power Wo of the power
accumulating device 11 is calculated on the basis of a measuring
value from the charging-discharging state measuring device 14A, and
predetermined limit power (contract power) of commercial power
(three-phase AC power source 1) is added to this discharging
ability power so that a limit power maximum value Wmax is
calculated (step S103). Namely, measuring values of the discharging
current and the discharging voltage from the charging-discharging
state measuring device 14A are inputted to the speed control
circuit 21A, and the speed control circuit 21A calculates a
corresponding limit discharging current from the table T1 shown in
FIG. 3. The speed control circuit 21A also calculates the
discharging ability power Wo by a product of the calculated limit
discharging current and the present discharging voltage, and adds
the limit power of commercial power to this calculated discharging
ability power Wo and calculates the limit power maximum value
Wmax.
[0061] The output power Wc of the inverter 4 is then compared with
the limit power maximum value Wmax. If the present output power Wc
is equal to the limit power maximum value Wmax, the previous
command speed is set to a late command speed to maintain the speed
at that time (step S104.fwdarw.S105). In contrast to this, if no
present output power Wc exceeds the limit power maximum value Wmax,
the command speed Vm according to the standard speed pattern is set
to the present command speed (step S104.fwdarw.S106). Conversely,
when the present output power Wc exceeds the limit power maximum
value Wmax, a new command speed is calculated by subtracting a
deceleration set value Dv from the previous command speed, and
using power is reduced (step S104.fwdarw.S107).
[0062] Thus, the speed control is performed on the basis of the
calculated command speed, and the calculated command speed is
stored to a built-in memory to prepare for the next calculation of
the command speed (step S108).
[0063] In this case, it is preferable that the limit discharging
current of the above table T1 has a margin in consideration of a
time delay, etc. At this time, it is not necessary to set a
deceleration degree to be increased so much in consideration of
rate of change in discharging ability power and ride feeling.
Accordingly, it is not necessary so much that an influence due to
deceleration is considered in the inverter 4 at a measuring time of
output power outputted at present. If it is necessary to consider
this influence, no output power outputted at present is used, but
it is sufficient to use expected power in constant running from the
present speed and load. The elevator is abruptly decelerated when
the present output power exceeds the limit power maximum value.
However, if processing such as smoothing to the deceleration, etc.
is performed in accordance with the present accelerating and
decelerating states, a more smooth speed control pattern is
obtained.
[0064] In the controller of the elevator constructed in this way,
while a limit of commercial power is kept, the speed of the
elevator can be stably controlled at a discharging time from the
power accumulating device 11 in a range in which no excessive
burden is imposed on the secondary battery 12. Accordingly, a cheap
power accumulating device having a long life can be
constructed.
[0065] Embodiment mode 2.
[0066] In this Embodiment mode 2, as shown in FIG. 5, the speed
control circuit 21A has a table T2 in which a full charging state
of the power accumulating device 11 is set to 100% and a limit
discharging current is set with respect to a charging degree SOC as
a value obtained by normalizing and accumulating a product of a
charging-discharging current and a charging-discharging voltage by
a capacity. The speed control circuit 21A calculates the limit
discharging current from the table T2 on the basis of the charging
degree SOC obtained on the basis of measuring values of the
discharging current and the discharging voltage from the
charging-discharging state measuring device 14A. The speed control
circuit 21A also calculates discharging ability power of the power
accumulating device 11 from the calculated limit discharging
current and the measuring value of the discharging voltage.
[0067] Namely, FIG. 5 shows a table of the limit discharging
current with respect to the present charging degree SOC of the
power accumulating device 11. The present charging degree SOC can
be calculated by accumulating charging and discharging currents or
power of the secondary battery 12. With respect to this present
charging degree SOC, a high discharging current can be generally
obtained at a high SOC level. However, no discharging current
(power) can be increased as the SOC level is reduced. FIG. 5 shows
this situation as a table.
[0068] Similar to the Embodiment mode 1, the speed control circuit
21A in this Embodiment mode 2 also calculates a command speed in
accordance with the flow chart shown in FIG. 4. Accordingly, while
a limit of commercial power is kept, the speed of the elevator can
be stably controlled at a discharging time from the power
accumulating device 11 in a range in which no excessive burden is
imposed on the secondary battery 12. Therefore, a cheap power
accumulating device having a long life can be constructed.
[0069] Embodiment Mode 3
[0070] In this Embodiment mode 3, the speed control circuit 21A has
plural tables T2a, T2b, T2c, . . . according to the temperature of
the secondary battery 12 of the power accumulating device 11 as
shown in FIG. 6. The speed control circuit 21A selects a table
according to a temperature measuring value of the
charging-discharging state measuring device 14A from the plural
tables. Similar to the Embodiment mode 2, the speed control circuit
21A then calculates discharging ability power of the power
accumulating device 11, and effects similar to those in the
Embodiment modes 1 and 2 can be obtained.
[0071] Embodiment Mode 4
[0072] In this Embodiment mode 4, as shown in FIG. 7, the speed
control circuit 21A has a table T3 in which a speed pattern (e.g.,
V01, V02, V03, . . . , VOn at a loadless time) according to a load
state is set. When it is judged on the basis of a measuring value
of the charging-discharging state measuring device 14A that the
power accumulating device 11 is broken, the speed control circuit
21A calculates the speed pattern from the above table T3 on the
basis of a car load measuring value measured by the car load
measuring instrument 25, and generates speed commands according to
the calculated speed pattern.
[0073] Namely, FIG. 7 illustrates a table showing the speed pattern
of speed control in the Embodiment mode 4. This table T3 shows the
pattern at an accelerating time, and describes a speed at each of
times t1, t2, t3, . . . , tn after departure. Smooth acceleration
can be realized by using this table T3. This acceleration table is
separately arranged on each of ascending and descending operation
sides. A deceleration pattern table corresponding to the above
acceleration is used on a deceleration side although this
deceleration pattern table is not described here. However, this
table generally uses a speed table with respect to the remaining
distance until stoppage instead of speed with respect to time. In
FIG. 7, items of no load, % load, etc. show patterns with respect
to the respective loads.
[0074] When a reduction in output of the power accumulating device
11 such as an excessive reduction in charging degree SOC level
caused by a certain cause (including breakdown) is known before
departure, the elevator can be smoothly operated within restriction
power of the three-phase AC power source 1 (commercial power) by
operating the elevator in a preset speed pattern. In an operating
pattern of the conventional elevator, no elevator has an operating
pattern according to a load. Therefore, when the elevator is
operated in a restriction power range of the commercial power, for
example, a loadless raising operation basically becomes a
regenerative operation and no discharging from the power
accumulating device 11 is required. In contrast to this, a power
running operation is performed in a loadless lowering operation so
that consumed power is large. Thus, the elevator can be operated at
an optimum speed by setting the speed table in accordance with
loads and directions.
[0075] Embodiment Mode 5
[0076] In this Embodiment mode 5, the speed control circuit 21A, as
shown in FIG. 8, has a table T4 in which maximum speed command
values V.sub.01max, V.sub.02max, . . . are set with respect to a
car load and discharging ability power of the power accumulating
device 11. The speed control circuit 21A calculates discharging
ability powers W01, W02, . . . of the power accumulating device 11
on the basis of a measuring value of the charging-discharging state
measuring device 14A. The speed control circuit 21A also calculates
the maximum speed command values V.sub.01max, V.sub.02max, . . .
from the above table T4 on the basis of a car load measuring value
measured by the car load measuring instrument 25 and the calculated
discharging ability powers. The speed control circuit 21A then
changes speed commands on the basis of comparison of the speed
commands and the maximum speed commands.
[0077] Control of the speed control circuit 21A in this Embodiment
mode 5 will next be explained with reference to a flow chart shown
in FIG. 9.
[0078] Speed control of the inverter 4 is first performed on the
basis of a command speed Vm according to a standard speed pattern
(step S501). Discharging ability power Wo of the power accumulating
device 11 is then calculated on the basis of a measuring value from
the charging-discharging state measuring device 14A (step
S502).
[0079] Thereafter, a corresponding maximum command speed Vmax is
calculated from the table T4 shown in FIG. 8 on the basis of a car
load measuring value of the car load measuring instrument 25 and
the discharging ability power Wo (step S503). Further, the command
speed Vm based on the standard speed pattern and the maximum
command speed Vmax are compared with each other (step S504).
[0080] If the present command speed Vm is equal to the maximum
command speed Vmax, the maximum command speed Vmax is set to a
command speed (step S504.fwdarw.S505). In contrast to this, when
the present command speed Vm does not exceed the maximum command
speed Vmax, a new command speed is calculated by subtracting a
deceleration set value Dv from the previous command speed to
decelerate the speed, and using power is reduced (step
S504.fwdarw.S506). Conversely, if the present command speed Vm
exceeds the maximum command speed Vmax, the command speed Vm based
on the standard speed pattern is set to a command speed (step
S504.fwdarw.S507).
[0081] Thus, speed control is performed on the basis of the
calculated command speed, and the calculated command speed is
stored to a built-in memory to prepare for the next calculation of
the command speed (step S508).
[0082] Accordingly, in accordance with the above Embodiment mode 5,
while a limit of commercial power is kept, the speed of the
elevator can be stably controlled at a discharging time from the
power accumulating device 11 in a range in which no excessive
burden is imposed on the secondary battery 12. Therefore, a cheap
power accumulating device having a long life can be
constructed.
[0083] Embodiment Mode 6
[0084] In this Embodiment mode 6, the speed control circuit 21A has
plural, as shown in FIG. 10, tables T5 in which a command speed
value of the elevator is stored every timer interruption of each
speed control. The plural tables T5 are separately arranged every
discharging ability power of the power accumulating device and
every load of the elevator. For example, when ten tables are
arranged every discharging ability power of the power accumulating
device and ten tables are arranged in each load every each of these
ten tables of the discharging ability power, a total number of
tables becomes 100. Further, as shown in FIG. 11, the speed control
circuit 21A has a table T6 in which a command speed according to
the remaining distance is set.
[0085] Namely, in this Embodiment mode 6, the speed control circuit
21A first calculates the command speed according to the remaining
distance on the basis of the table T6 as shown in FIG. 11. Further,
the speed control circuit 21A calculates the discharging ability
power of the power accumulating device on the basis of a measuring
value of the charging-discharging state measuring device. The speed
control circuit 21A then selects a table T5 as shown in FIG. 10 in
accordance with both data of the discharging ability power and a
car load measuring value measured by the car load measuring
instrument 25 on the basis of this car load measuring value. The
speed control circuit 21A calculates the command speed from the
selected table every control timer interruption. At a timer
interruption time, for example, the speed control circuit 21A
calculates v1 as a command speed at the timer interruption time
just after start, and calculates v2 as a command speed at the next
timer interruption time.
[0086] Control of the speed control circuit 21A in this Embodiment
mode 6 will next be explained with reference to a flow chart shown
in FIG. 12.
[0087] The flow chart shown in FIG. 12 is started every timer
interruption. First, a command speed is calculated in accordance
with the remaining distance until an object floor with reference to
the table T6. For example, if the remaining distance until the
object floor is equal to or greater than dl, the command speed Vd
according to the remaining distance is set to vd1. If the remaining
distance until the object floor is equal to or smaller than d1 and
exceeds d2 (d1>d2 and command speeds are arranged in a long
order of the remaining distance in the table), the command speed Vd
according to the remaining distance is set to vd2. Hereinafter, the
command speed Vd according to the remaining distance is set in
accordance with this table T6 (step S601).
[0088] A command speed Va according to the number of timer
interruption times is next set. Namely, since there is periodically
a timer interruption, a table T5 shown in FIG. 10 is selected in
accordance with both data of the discharging ability power and the
car load measuring value every time from start. The command speed
Va according to the number of timer interruption times is set from
the selected table T5 every control timer interruption (step S602).
Since the speed is set to a highest speed in a final table T5,
Va=Vmax is set after that.
[0089] Next, the command speed Va every timer interruption is
compared with the command speed Vd according to the remaining
distance. If the command speed Va every timer interruption exceeds
the command speed vd according to the remaining distance, the
command speed is set to Vd (step S603.fwdarw.S604). In contrast to
this, if no command speed va every timer interruption exceeds the
command speed Vd according to the remaining distance, the command
speed is set to Va (step S603.fwdarw.S605). Namely, the speed of
the elevator is accelerated in accordance with the table T5 shown
in FIG. 10 at an accelerating time, and is decelerated in
accordance with the table T6 shown in FIG. 11 at a decelerating
time. Thus, the speed control can be smoothly performed until an
object floor.
[0090] As mentioned above, in accordance with this invention, it is
possible to construct an elevator which can perform stable speed
control by using a cheap power accumulating device of a low
capacity even at a discharging control time, and has the power
accumulating device having a long battery life without reducing
energy saving effects.
* * * * *