JPS61135392A - Elevator drive system - Google Patents

Abstract

PURPOSE:To operate a single-phase AC power source while using a 3-phase AC motor for driving a cage by using frequency converting means which inputs single-phase AC power and outputs variable frequency 3-phase AC power. CONSTITUTION:A single-phase AC power from a single-phase AC power source 8 is input through a reactor 9 to the single-phase inverter (single-phase power reactor) 11 of a frequency converter 10, and supplied as DC power to a DC intermediate circuit of a smoothing condenser 12. Further, it is converted by 3-phase inverter (3-phase power inverter) 13 to the prescribed 3-phase AC power, and supplied to a 3-phase induction motor 6 to operate an elevator.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an elevator that uses a three-phase AC motor to drive a car, and particularly to an elevator that can be operated using a single-phase AC power source. [Background of the Invention] Modern society involves various types of energy consumption, and among these, sleepy energy has become indispensable.

This electrical energy, so-called electric power, is almost always supplied as three-phase AC power, except for small-scale electricity such as for household use. Phase AC motor.

Above all, three-phase induction motors are mainly used.
It is also widely used to drive elevator cars.

On the other hand, in order to improve the control characteristics of elevators that use such three-phase AC motors to drive cars, for example, a frequency converter that combines a converter and an inverter is used to make the three-phase AC motor variable. Frequency control systems have come into widespread use in recent years, such as the one disclosed in Japanese Utility Model Application Publication No. 59-8968.

Incidentally, in recent years, there has been a change in the value of elevators, and demand for elevators is expected to be seen in buildings with low floors of 2 to 3 floors and general residences.

However, as mentioned above, most conventional elevators use three-phase AC motors, and even those that perform variable frequency control, as shown in the above publication, all use three-phase AC power as a power source. On the other hand, in most of the above-mentioned low-floor buildings and general residences, only single-phase AC power is supplied.

For this reason, in the past, in order to install an elevator in such low-floor buildings or general residences, power distribution using three-phase power lines was required, which increased costs and in some cases The disadvantage was that it was impossible to distribute electricity and the elevators could not be energized.

Furthermore, since we are trying to use single-phase AC power,
A single-phase AC motor, such as a single-phase induction motor, is used in an elevator.
It is conceivable to use it for driving purposes.

However, as is well known, single-phase machines are larger than three-phase machines, have more losses, and are rarely available as general-purpose products on the market except for small-capacity ones.
Using a single-phase machine has the drawback of significantly increasing costs.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide an elevator at low cost that can be operated using a single-phase AC power source while using a three-phase AC motor to drive the car.

[Summary of the invention]

In order to achieve this object, the present invention uses a frequency conversion means that inputs single-phase AC power and outputs variable frequency three-phase AC power, and supplies this output to a three-phase AC motor for driving a car. It is characterized by the following points.

[Embodiments of the invention]

Hereinafter, the elevator driving system according to the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows an embodiment of the present invention. In this figure, an elevator car 1 is connected to a counterweight 2 by a rope 3, and suspended from a driving sheep 4 in a hanging shape.

The sheep 4 is connected to a three-phase induction motor 6 via a speed reducer 5, and is locked by an electromagnetic brake 7 when stopped.

On the other hand, the single-phase AC power from the single-phase AC power supply 8 is inputted to the single-phase inverter (single-phase forward converter) 11 of the frequency converter 10 via the handle 9, and the DC intermediate circuit consisting of the smoothing capacitor 12 receives the DC power. The electric power is supplied as electric power, which is further converted into three-phase AC power of a predetermined voltage by a three-phase inverter (three-phase inverter) 13, and then supplied to the three-phase induction motor 6 to operate the elevator. It is done.

This single-phase converter 11 has a gate turn-off thyristor (Gate TtLrn 0-ff Thyris
tor ) GTO and diode D are connected in antiparallel to form a bridge configuration for a single-phase AC power supply, and as is well known, each GTO is connected to a half cycle (
(positive or negative), the required power conversion for driving 1-1 can be performed with a plurality of waveform width pulses. That is, single-phase AC power supply 8
It is used for both the forward converter that converts DC into DC and supplies it to the load after capacitor 12, and the inverse converter 5 that performs the reverse conversion, and can make the input current and voltage almost sinusoidal. be.

Furthermore, this converter 11 operates as a well-known step-up chopper due to the action of a reactor 9 inserted between it and the single-phase AC power supply 8, thereby performing a step-up operation, which is one of the features of this embodiment. , DC intermediate circuit capacitor? K is set so that the terminal voltage of the terminal 12 can be made higher than the peak voltage of the power supply 80. Hereinafter, this boosting operation will be explained with reference to FIG. Note that here, in order to make the explanation easier to understand, the explanation will be continued with the single-phase AC power source 8 replaced with the DC power source 81.

First, assume that the polarity of the voltage ER of the power supply 810 is as shown in FIG. It flows in a loop shown by the solid line. Therefore, energy is stored in the reactor 9. This energy increases the GTO2 (7) ON time by 'rON'.
It is expressed as ER・IP-TON.

Next, when the GTO 2 is turned off, the energy stored in the reactor 9 causes a current I to flow from the beam handle 9 to the diode D1 to the condenser 12 and the load circuit to the reactor 9 via the diode D4 in a loop shown by a broken line. The energy stored in the reactor 9 is then transferred to the capacitor 12 and the load circuit. The energy at this time is (E tL −E
R) Represented by IR・'royy. On the other hand, this O
During the FF period, diodes D1 and D are simultaneously connected from the power supply 81.
4 to the capacitor 12 and the load circuit
If we calculate the capacitor terminal voltage Ed where the energy represented by IR” TOFF is supplied, then from the law of conservation of energy, ER11R0TON = (Ed - ER) IR0TOFF
Ed=ER(TON+TOFF)/TOP
IF=ER-T/TOFF However, T=ToN+TOFF: Switching period, therefore, T/TOPIF≧1.

Therefore, the capacitor 120 voltage Ed is determined under this condition (T
/TOFF≧1), this capacitor 12 becomes higher than the power supply voltage ER, and by changing the OFF time TOFF and switching period T of GTO2.
This means that the voltage Ed of can be controlled.

Next, suppose that the polarity of the voltage ER of the power supply 81 is as shown in FIG. When turned off, a current due to the energy stored in the reactor 9 flows along the loop shown by the broken line.

Therefore, at this time as well, the capacitor 12 has α
), it is possible to supply a voltage Ed with the same polarity as in the case of #81 and higher than the voltage ER of the power supply 81.
Even if there are 11 sources at each intersection, the voltage ECt of the capacitor 12 is changed to the voltage E of the power supply by controlling T/rOFF.
It can be seen that a predetermined approximately constant voltage higher than R can be achieved.

Returning to FIG. 1, the control operation of the voltage Ej described above is as follows.
It is done with K. That is, the voltage command signal given from the DC voltage setting device 14 and the voltage Ed of the capacitor 12
The comparator 16 compares the detection signal of the DC voltage detection circuit 15 that detects the Obtain a control signal for this G
The ON/OFF time of TO is controlled so that the voltage Bd becomes a predetermined voltage value. Furthermore, at this time,
A single-phase AC voltage from a single-phase power supply 8 is input to the PWM signal generator 18 via a transformer 19, so that the PWM signal generator 18 can detect the polarity of the voltage of the power supply 8. There is.

Next, the three-phase inverter 13 is explained. This inverter 13 is also composed of a GTO and a diode D, and operates as a voltage source PWM inverter with a DC intermediate circuit formed by a capacitor 12, and transfers variable voltage three-phase power to the induction motor 6. supply to. On the other hand, the control operation No. 7 is performed by the speed control device 22 which receives the speed command from the speed command generator 20 and the speed feedback signal from the speed generator 21 as input.

Next, the operation of the frequency converter 10 including the single-phase inverter 11 and the three-phase inverter 13 will be explained below.
First, the single-phase converter 11 is connected to the single-phase AC power supply 8 or the third
As shown in the figure, a single-phase AC voltage gH having a peak value voltage ERM is input, and it is converted into a DC voltage Ed (A-EHM) determined by the setting value of the DC voltage setting device 14. Furthermore, as is clear from the above explanation, this constant can be set to (k≧1), so that if the rated voltage of the three-phase induction motor 6 is EM, then (EM>ER
M), the three-phase inverter 13 can obtain the DC input voltage Ed necessary to generate the three-phase AC voltage of this voltage EM.

On the other hand, as shown in FIG. 4, the three-phase inverter 13 performs PWM operation under the DC input voltage Ed, and generates a PWM three-phase AC voltage with a frequency of f and a fundamental voltage of e. and supplies it to the three-phase induction motor 6.

Therefore, when controlling the acceleration of the elevator, first, the electromagnetic brake 7 is released, and the speed control device 22 generates a PWM signal based on the speed command from the speed command generator 20, as shown in FIG. That is, while maintaining a relationship such that the ratio -/f between the output voltage ε of the inverter 13 and the frequency f is approximately constant, the frequency f is increased from approximately zero to the frequency f1 corresponding to the rated speed of the elevator, This causes the three-phase induction motor 6 to accelerate from zero speed to the rated speed of the elevator under a predetermined torque commensurate with the slip frequency. As a result, the car 1 is accelerated via the speed reducer 5 and the sheep 4. Note that at this time, the reason why the ratio C/f is kept substantially constant is to keep the internal magnetic flux of the electric motor 6 substantially constant and to generate efficient torque (torque).

Next, the elevator deceleration control is performed by a speed command generator 20.
In response to the signal, the speed control device 22 decreases the frequency f from the rated frequency 11 to zero. Meanwhile, in parallel with this, converter 110GTO is controlled to perform power regeneration, and thereby electric motor 6 generates regenerative braking torque to decelerate and then stop the elevator. When the car 1 has stopped in this manner, the electromagnetic brake 7 is returned to hold the car stopped.

Therefore, according to this embodiment, an elevator using a three-phase induction motor 6 can be operated using single-phase power from a single-phase power source 8. In addition, the rated voltage EM of this motor 6
(''1) is, for example, 200 [:V], and on the other hand, even if the single-phase power supply 80 military pressure 11R is, for example, 1oo (v'), the elevator can be efficiently operated without using a transformer or the like. - can be driven.

Next, another embodiment of the present invention will be described with reference to FIG.

The embodiment shown in Fig. 6 uses a storage battery in the DC intermediate circuit and can be operated during a power outage. The device 25 is an alternating current control signal generating device for obtaining alternating current power by operating the single-phase converter 11 as an inverter using the storage battery 120 as a power source during a power outage;
26 and 27 are contacts that open in response to a signal from the power failure detection device 23, 28 a contact that closes in response to the signal, and 29 a brake control contact.

30 is a contact for controlling the door motor, 31 is a door motor for opening and closing the door, and 120 is a storage battery, and the rest is the same as the embodiment shown in FIG.

With the above circuit configuration, the single-phase converter 11 can function as a step-up DC converter, a charger for charging a storage battery, an inverter for regenerating power, and an inverter for generating control circuit power during a power outage. .

Here, the relationship of each voltage to the single-phase AC power supply 8 will be explained. Single phase AC power supply 80 wave peak value ER1 storage battery 120
If EB is the rated voltage of EB, Ed is the DC conversion voltage by the single-phase converter 11, and EM is the rated voltage of the three-phase induction motor 6, then equation (2) is set.

ER<EB≦Ed≦EM (2) However, Ed and EB must have a voltage value necessary to maintain the effective value E after AC conversion by the PWM inverter 13. That is, when the voltage of the single-phase AC power supply 8 is 100 (V:] (effective value), if the three-phase induction motor 6 with a rated voltage of 200 CVD is used, the voltage EB of the storage battery 120 is at least (v/ Tx 20
0) [v], and the voltage Ed of the DC intermediate circuit obtained by further boosting by the single-phase converter 11 is set as follows.

Ed≧Es=1 block x 200 CV) Next, the operation of the embodiment shown in FIG. 6 will be explained.

Elevator - Contacts 26°27 during suspension and at night
is closed. Therefore, the storage battery 1200 voltage E
When B is lower than the set voltage El of the DC voltage setter 14, the single-phase converter 11 acts as a charger and charges the storage battery 120 until the storage battery voltage EB reaches Ed.

During normal operation, contacts 26 and 27 are closed as described above, and contact 29 is further closed by an operation signal (not shown).
are also closed, and as a result, power is also supplied to the storage battery 120 and the brake 7 is released.

The speed control device 22 operates based on the speed command from the speed command generator 20 and the speed feedback signal from the speed detector 21, and operates based on the frequency f and voltage of the power to be supplied from the three-phase inverter 13 to the motor 6. - is maintained in the relationship shown in Figure @3, that is, the ratio of g/f is constant.
Generates WM signal. At this time, the voltage E of the storage battery 120
When B matches the set voltage El of the DC voltage setter 14, the power output from the inverter 13 is supplied from the storage battery 120, but if the set voltage Eel and the storage battery voltage EB are Eco≧EB. When K is single-phase power supply 8
Electric power is supplied from there through the single-phase converter 11.

On the other hand, during deceleration, the storage battery 120 is charged by the regenerated power, but when the battery voltage EB becomes higher than the set voltage E, the Km force on the single-phase power supply 8 side is regenerated via the single-phase converter 11, and therefore the battery voltage EB remains almost constant.

When the car 1 reaches the stop position, the contacts 29 are opened by an operation signal (not shown), and the brake 7 maintains the stop. At the same time, the contact 30 is also opened.

The door motor 31 on the car 1 operates to open and close the door 1.
Passengers are boarded and alighted.

Next, we will explain what happens during a power outage. When a power outage occurs, a power outage signal is generated from the power outage detector 23, and the contacts 26°27, 2
9 is opened, and furthermore, P via the speed command generator 20
Driving of the WM inverter 13 is stopped.

Therefore, the power to the three-phase induction motor 6 is cut off, and the brake 7 is operated to keep the elevator stopped.

Further, the contact 28 is closed, thereby connecting the AC control signal generation circuit 28 to the single-phase converter 11 .

Then, the GTO of the single-phase converter 11 is controlled by the gate signal from this circuit 28, and as a result, the single-phase converter 11 performs inverter operation using the storage battery 120 as a power source, and generates a single-phase AC output on its AC input side. However, this power is started to be supplied to the voltage converter 24, and as a result, operating power continues to be input to each control device in the same way as during normal operation, even though the power is interrupted.

Therefore, according to this embodiment, even if a power outage occurs while the elevator is in operation, the operation can be continued until the storage battery 120 is discharged, and rescue operations can be carried out reliably. In order to do this, it is necessary to configure the output voltage of the voltage converter 24 to be maintained until the inverter operation by the single-phase converter IIK starts in the event of a power outage. There is no particular problem as long as a capacitor or battery is provided.

Incidentally, in the above embodiment, the switching elements of the single-phase converter 11 and the three-phase inverter 13 are constructed of GTo, but the present invention is not limited to this. It may also be composed of a control element.

Furthermore, the control of the induction motor by the frequency conversion device is not limited to vector frequency control in which i v/f is kept constant as in the above embodiments, but may also use a vector control method.

Furthermore, it goes without saying that the single DC intermediate circuit is not limited to one of a capacitor and a storage battery, but may also be used in parallel with both.

〔Effect of the invention〕

As explained above, according to the present invention, an elevator can be operated efficiently using a single-phase AC power source without significantly increasing costs. An elevator that can be easily installed in places such as
The driving method can be easily provided.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the elevator drive system according to the present invention, Fig. 2 (α) and (b) are explanatory diagrams of boosting operation by the converter, and Fig. 3 is the relationship between input and output of the converter. A waveform diagram showing the inverter's P
FIG. 5 is a characteristic diagram showing the relationship between the output voltage and output frequency of the inverter, and FIG. 6 is a block diagram showing another embodiment of the present invention. 1... Car, 6... Three-phase induction motor, 8... Single-phase AC a' source, 9... Reactor, 10... ...Frequency conversion device, 11...
...Single-phase converter, 12...Capacitor,
13... Three-phase inverter, 14... DC voltage setting device, 20... Speed command generator, 21
... Speed generator, 22 ... Speed side device, 23 ... Power failure detector, 24 ... Voltage converter, 25 ......・AC control signal generation circuit,
120...Storage battery. Figure 2 (b) TO4! 3 Prisoners 1! 4 FiguresOfIf (Vs)

Claims (1)

[Claims] 1. In an elevator that controls the operation of a car by supplying variable frequency three-phase AC power to a three-phase AC motor for driving the car, converting single-phase AC power into variable frequency three-phase AC power 1. An elevator drive system characterized in that the elevator is operated by a single-phase AC power supply by providing a frequency conversion means for converting the frequency and supplying the output of the frequency conversion means to the three-phase AC motor. 2. The elevator drive according to claim 1, wherein the frequency conversion means is composed of a single-phase forward conversion section and a three-phase reverse conversion section that are coupled to each other via a DC intermediate circuit. method. 3. Claim 2 is characterized in that the forward conversion section has a step-up chopper function using a reactor and is configured to generate a DC output voltage higher than that on the single-phase AC power supply side. Elevator drive system. 4. The elevator driving method according to claim 2, wherein the forward conversion section is also provided with a reverse conversion function and is configured to perform power regenerative braking control. 5. Claim 2 is characterized in that the DC intermediate circuit includes a storage battery, and the elevator can be operated using at least one of the storage battery and the single-phase power source as a power source. Elevator drive system. 6. In claim 3, the voltage of the single-phase AC power supply is 100V, and the rated voltage of the three-phase AC motor is 2.
Elevator drive system characterized by being selected as 00V.