Elevator controller

Details Elevator controller Elevator controller

2003-03-18

2004-12-07

Salata, Jonathan (Department: 2837)

Elevator, industrial lift truck, or stationary lift for vehicle

Having specific load support drive-means or its control

Includes control for power source of drive-means

C187S296000

Reexamination Certificate

active

06827182

ABSTRACT:

TECHNICAL FIELD
The present invention relates to an energy-saving type elevator control apparatus to which a secondary battery is employed.
BACKGROUND ART
FIG. 5
is a basic structural diagram showing a conventional elevator control apparatus to which a secondary battery is employed for controlling the elevator. In
FIG. 5
, reference numeral
1
denotes a three-phase A.C. power source, and reference numeral
2
denotes a converter constructed by diodes and the like for converting an A.C. power outputted from the three-phase A.C. power source
1
into a D.C. power. The D.C. power which has been obtained through the conversion in the converter
2
is supplied across D.C. buses
3
.
In addition, reference numeral
4
denotes an inverter, which is controlled by a speed controller, as will be described later, for speed position control for the elevator. Thus, the inverter convert a direct current supplied through the D.C. buses
3
into an alternating current of a variable voltage and a variable frequency to supply the resultant alternating current to an A.C. motor (not shown) to rotate and drive a hoisting machine
5
of the elevator directly connected to the A.C. motor, thereby controlling ascending and descending of a car. A rope wound around the hoisting machine
5
is connected to the car and to a counter weight to allow a passenger in the car to move to a predetermined floor.
Here, the weights of the car and the counter weight are designed in such a way that they become roughly equal to each other when passengers one half the capacity get in the car. That is to say, in the case where the car is moved up and down with no load, the operation becomes a power running operation when the car is moved down, while becoming a regenerative operation when the car is moved up. Conversely, in the case where the car is moved down with the capacity load, the operation becomes the regenerative operation when the car is moved down, while becoming the power running operation when moving up the car.
In addition, reference numeral
6
denotes an elevator control circuit which is constructed by a microcomputer and the like, and which carries out the supervision/control of the whole elevator. Reference numeral
7
denotes a speed controller for carrying out the speed control of the elevator, reference numeral
8
denotes a charge/discharge control circuit, reference numeral
9
denotes a power accumulator provided across the D.C. buses
3
for accumulating therein a power during the regenerative operation of the elevator and for supplying the accumulated power to the inverter
4
together with the converter
2
during the powering operation, reference numeral
10
denotes a regenerative control circuit, reference numerals
11
and
12
respectively denote a regenerative control gate and a regenerative resistor which are connected across the D.C. buses
3
, reference numeral
13
denotes a bus voltage measuring apparatus for measuring a bus voltage of the D.C. buses
3
, and reference numeral
14
denotes a charging/discharging state measuring circuit for measuring a charging/discharging state of the power accumulator
9
. The above-mentioned charge/discharge control circuit
8
controls the charge/discharge of the above-mentioned power accumulator
9
on the basis of a measured value from the bus voltage measuring apparatus
13
and a measured value from the above-mentioned charging/discharging state measuring circuit
14
.
Here, the above-mentioned power accumulator
9
, as in an example of a circuit shown in
FIG. 6
, is constructed by a secondary battery
90
of nickel-hydrogen or the like and a DC-DC converter for controlling charge/discharge of the secondary battery
90
. The DC-DC converter includes a reactor
91
, switching elements
92
and
93
such as IGBTs, and diodes
94
and
95
which are respectively connected in antiparallel with the switching elements
92
and
93
. The charge for the secondary battery
90
is carried out with a step-down chopper circuit of the switching element
92
as the charge gate and the diode
95
, while the discharge from the secondary battery
90
is carried out with a boosting type chopper circuit of the switching element
93
as the discharge gate and the diode
94
. These gates are controlled by the charge/discharge control circuit
8
.
In general, in order that the power accumulator
9
may be configured so as to be small and of low cost, the number of secondary battery
90
is reduced to be less, and hence the output voltage of the batteries is lower than the voltage across the D.C. buses
3
. The voltage across the D.C. buses
3
is basically controlled so as to become near a voltage Vp which is obtained by rectifying the voltage of the three-phase A.C. power source
1
. Thus, when charging the batteries with electricity, an input voltage to the power accumulator
9
needs to be decreased as a value lower than the voltage Vp down to the bus voltage, and also during the discharge, an output voltage of the power accumulator
9
needs to be increased or decreased as a value higher than the voltage Vp from or to the bus voltage. For this reason, the DC-DC converter is adopted.
In addition, a quantity exhibiting the degree of charge for the power accumulator
9
is called an SOC (state of charge), and this state of charge, SOC, is calculated on the basis of the difference between a quantity of charged current and a quantity of discharged current as described above. That is to say, a quantity of charged current is set plus, and a quantity of discharged current is set minus with the state of full charge of the power accumulator
9
as 100% to calculate the current SOC, i.e., a quantity of charge.
When the three-phase commercial power source
1
is in the state of a power failure, the operation of the elevator becomes possible through the power source supply from the power accumulator
9
. In general, the secondary battery is used in the form in which sets of batteries each having about ten or less plural cells connected in series with one another are further connected in series with one another. However, if, for example, the number of series combinations of the secondary battery is selected so as to have the charge/discharge capability with which about one half the rated output of a motor depending on the speed and the load capacity of an elevator, then all of the regenerative powers can be charged since the regenerative power is about one half the rated electric power, and hence the maximum effect can be expected for the energy saving. In addition, at the time of a power failure, period of time (distance) during which the operation is possible is determined on the basis of a quantity Wh of power accumulated in the power accumulator
9
. Conversely, if from the SOC in the normal running before a power failure to the SOC from start to finish of the discharge (here, the SOC from start to finish of the discharge means the SOC in which the discharge is possible in the range of not degrading batteries, and hence if the power is supplied in order to operate an elevator, then the terminal voltage of the secondary battery is abruptly decreased so that the desired power can not be supplied in some cases) is from 70% to 30% for example, in this case, when a quantity of power required to operate an elevator for a predetermined period of time in a power failure is 40% of the rated power, the number of series combinations of the secondary battery can be selected accordingly.
FIG. 7
is a flow chart showing the control for the charging gate and the discharging gate made by the charge/discharge control circuit
8
. First of all, for example, the bus voltage is measured with the bus voltage measuring apparatus
13
(Step S
1
), and the measured voltage is compared with a desired voltage set value exhibiting the regenerative state (the desired voltage set value is equal to or smaller than a voltage set value which is set in the discharge control as will be described later, and is the value exhibiting the regenerative state which the D.C. bus voltage rises due to the rege

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