JPH0632546A - Control device for four quadrant operation loading device - Google Patents

Abstract

PURPOSE:To utilize the regenerative energy effectively, and save the electric power in a device, which performs the four quadrant operation of power running, regeneration, lowering and elevating by switching the connection of an energy absorbing capacitor to a direct current smoothing capacitor to either of series connection and parallel connection. CONSTITUTION:A device, in which the direct current output of a rectifier 3 connected to a commercial electric power source 1 through an electromagnetic contactor 2 is converted to the alternating current by an inverter 7 and supplied to an electric motor 8 for an elevator device, is provided with a voltage detector 14 for detecting the voltage of both ends of a smoothing capacitor 6 for smoothing the direct current output of the rectifier 3. In the case where the detection value thereof is equal to the reference voltage or more, a control circuit 26 gives the ON command to any one of switching elements Q1-Q6 so that an energy absorbing capacitor 15 is connected in parallel with the smoothing capacitor 6. In the case where the detection value is equal to the reference value or less, the control circuit 26 gives the ON command to any one of switching elements Q1-Q6 so that the capacitor 15 is connected in series to the capacitor 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a four-quadrant operation load device, such as an elevator and a crane, which performs a four-quadrant operation including a power running operation, a regenerative operation, a descending operation and an ascending operation.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a main circuit of an elevator using a voltage-source inverter, which is currently the mainstream, and includes a commercial power supply 1, contacts 2 of an electromagnetic contactor, a diode rectifier 3, and a regenerative circuit. Resistor 4, semiconductor switch 5 for regeneration,
It includes a DC smoothing capacitor 6, a three-phase inverter bridge 7, an induction motor (IM) 8, a reduction gear 9, a main jib 10, a deflecting sheave 11, a counterweight 12, a car 13, and a voltage detector 14.

An elevator is generally a car 13 in which passengers ride.
And the counter weight 12 are connected in a slip manner.
Normally, the counterweight 12 is selected to have a weight that balances about half of the capacity, and the elevator receives the unbalanced torque of the car and the counterweight 12 according to the driving direction according to the number of passengers. I am driving.

Therefore, when the load of the car 13 is lighter than the counterweight 12, no force is required in the ascending direction, and conversely, in the descending direction, the driving force must be applied from the electric motor 8. . Similarly, basket 1
When the load of 3 is heavy against the counterweight 12, no force is required in the descending direction, but in the case of the ascending direction, the driving force must be applied from the electric motor 8.
As described above, depending on the loading state of the car 13 and the operating direction, basically, the operation in which power is viewed from the electric motor 8, that is, the operation in which energy is returned without a power opposite to the power running operation, that is, the regenerative operation is basically performed. Appears at half the rate. Furthermore, if we consider the ideal state in which there is no mechanical loss or electrical loss, and all the passengers who have risen in the car 13 come down from the same floor, the law of energy conservation says that energy consumption I don't think there is. In reality, there are mechanical loss, electrical loss, wind loss, friction loss, etc., which is not ideal, but during regeneration, a corresponding amount of energy returns. But,
Under the present circumstances, the energy at the time of regeneration is hardly used effectively.

This will be described with reference to FIG. During power running, energy is supplied from the commercial power source 1 to the electric motor 8 via the rectifier 3 and the inverter 7 to operate the elevator. During regeneration, the electric motor 8 operates as a generator, so that the DC smoothing capacitor 6 is charged by the DC voltage rectified by the transistor of the inverter 7, for example, the IGBT, and the voltage across the capacitor 6 rises. The voltage detector 14 detects this voltage across both ends, and when the detected value exceeds a certain set voltage, the regenerative semiconductor switch 5 is turned on. As a result, the regenerative current flows into the regenerative resistor 4, and here the Joule heat, that is, the power consumption W is consumed according to the equation (1).

W = RI ² = R (V1 / R) ² = V1 ² / R (1) where R is the regenerative resistance value, I is the resistance current, and V1 is the ON voltage of the semiconductor switch 5. According to the equation (1), the regenerative electric power is usually consumed in the form of Joule heat or consumed as heat in the electric motor 8.

[0007]

A high-speed, ultra-high-speed Gareth elevator may have a system that regenerates to a commercial power source, but the number of units is small and a reversing type wattmeter is not used by the customer. In this case, the current situation is that there is no direct saving in electricity bills.

[0008] There is also a proposal to take out regenerative energy and use it for other power sources, water heaters, etc. However, the energy supplied varies, and there is not always such a reasonably usable load.

There is also a system in which the number of units is collectively supplied to each elevator by supplying regenerative energy to the elevators in the power running mode, but a plurality of elevators are required to achieve the effect, and regenerative energy is not always required. And powering do not always balance well, and the system scale increases.

Further, a system has been proposed in which a battery is connected in parallel to the DC smoothing capacitor of the main circuit to absorb the regenerative energy, but in order to make the device large and sufficiently absorb the regenerative energy. Requires that the internal resistance of the battery be kept low, and the number of batteries also increases.

Furthermore, there is also a method of increasing the capacity of the DC smoothing capacitor, but this is also not practical because the capacity must be extremely large in order to sufficiently absorb the regenerative energy.

As described above, in the current system,
It is the actual situation that it cannot be used unless the energy that is regenerated is thoroughly discarded or a fairly large system is configured, and from the viewpoint of energy saving, development of a device that can effectively use this energy with a simple configuration is desired. . An object of the present invention is to provide a control device for a four-quadrant operation load device that can effectively use regenerative energy with a simple configuration and reduce power consumption.

[0013]

SUMMARY OF THE INVENTION An invention according to claim 1 is a four-quadrant, in which a first power converter for converting alternating current into direct current and a direct current output of the first power converter are converted into alternating current. A second electric power converter for giving an electric motor for driving an operating load, and an input side of the second electric power converter and an output side of the first electric power converter, which are connected in parallel, and the first electric power converter is provided. A DC smoothing capacitor for smoothing the DC output of, and a plurality of switching elements between the DC smoothing capacitor and the first power converter, which are connectable in parallel and in series with the DC smoothing capacitor. A connected energy absorbing capacitor, a voltage detector that detects the voltage across the DC smoothing capacitor, and the energy absorbing capacitor when the detection value detected by this voltage detector exceeds a reference voltage. An ON command is given to the switching element so as to be connected in parallel to the DC smoothing capacitor, and when the detected value detected by the voltage detector is equal to or lower than a reference voltage, the energy absorbing capacitor is connected in series with the DC smoothing capacitor. A control device for a four-quadrant operation load device, comprising a control circuit for giving an ON command to the switching element so as to be connected.

The invention corresponding to claim 2 is the first power converter for converting alternating current into direct current, and the electric motor for converting the direct current output of the first power converter into alternating current to drive the four-quadrant operating load. And a second power converter that is connected to the input side of the second power converter and the output side of the first power converter in parallel to smooth the DC output of the first power converter. A direct current smoothing capacitor, and an energy absorbing device connected between the direct current smoothing capacitor and the first power converter in combination with a plurality of switching elements in parallel and in series with the direct current smoothing capacitor. A capacitor, a voltage detector for detecting the voltage across the DC smoothing capacitor, and the energy absorbing capacitor for detecting the voltage across the DC smoothing capacitor when the detection value detected by the voltage detector exceeds a reference voltage. An ON command is intermittently given to the switching element so as to be connected in parallel to the capacitor, and when the detected value detected by the voltage detector is equal to or lower than a reference voltage, the energy absorbing capacitor is connected in series with the DC smoothing capacitor. A control device for a four-quadrant operation load device, comprising a control circuit for intermittently giving an ON command to the switching element so as to be connected.

[0015]

According to the inventions corresponding to claims 1 and 2,
The voltage across the DC smoothing capacitor is detected, and the detected value is compared with the reference voltage.If the detected value is large, the energy absorbing capacitor is connected in series with the DC smoothing capacitor, and the detected value and the reference voltage When the detected values are small by comparing the voltages, the energy absorbing capacitor is connected in parallel to the DC smoothing capacitor, so regenerative energy can be effectively used with a simple configuration, and power consumption can be reduced.

[0016]

FIG. 1 is a circuit diagram showing an embodiment of the present invention. Here, an elevator will be described as an example of a four-quadrant operation load device, but a crane or the like can be used in the same manner as well.

In this embodiment, a diode rectifier 3 constituting a first power converter for converting AC into DC and a motor 8 for converting a DC output of the rectifier 3 into AC and driving a four-quadrant operation load are provided. And a second power converter for providing an IGBT (Insulated Gate Bipolar Transis
tor: Insulated gate bipolar transistor: This is hereinafter referred to as a switch. ) And a diode, a DC smoothing capacitor 6 connected in parallel to the input side of the inverter 7 and the output side of the rectifier 3, and smoothing the DC output of the rectifier 3, the DC smoothing capacitor 6 and the rectifier 3. Between the DC smoothing capacitor 6 and the energy absorbing capacitor 15 connected in parallel or in series, and the energy absorbing capacitor 15
Switch Q for connecting the motor 8 in parallel to the DC smoothing capacitor 6 during power running, or connecting the motor 8 in series to the DC smoothing capacitor 6 during regeneration.
1, Q2, Q3, Q4, Q5, Q6 and diode D
1, D2, D3 and the reactor 19, a voltage detector 14 for detecting the voltage across the DC smoothing capacitor 15,
It is composed of a control circuit 26 which gives an ON command to the switches Q1 to Q6 so as to connect the energy absorbing capacitor 15 to the DC smoothing capacitor 6 in series or in parallel according to the detection value detected by the voltage detector 14. .

The diode D1 is connected in series to the cathode on the output side of the rectifier 3 and the input side of the inverter 7, the collector of the switch Q1 is connected to the connection point between the diode D1 and the inverter 7, and the reactor 19 is connected to this emitter. The energy absorbing capacitor 15 is connected in series, the collector of the switch Q2 is connected to the capacitor 15, and the emitter of the energy absorbing capacitor 15 is connected to the output side anode of the rectifier 3 and the input side of the inverter 7 to form the base and the emitter of the switch Q1. , The base and emitter of the switch Q2 are connected to the control circuit 26.

The emitter of the switch Q4 is the switch Q1.
Of the connection between the base and the voltage detector 14 and the control circuit 26
, The base of the switch Q4 is connected to the control circuit 26, and the collector of the switch Q4 is connected to the connection point between the emitter of the switch Q1 and the reactor 19.

Further, the collector of the switch Q6 is connected to the collector of the switch Q4 via the diode D3.
The emitter is connected to the connection point between the reactor 19 and the capacitor 15 and the control circuit 26, and the switch Q6
Is connected to the control circuit 26.

The emitter of the switch Q3 is connected to the connection point between the emitter of the switch Q1 and the reactor 19, and the emitter and the base of the switch Q3 are respectively connected to the control circuit 2.
6 and the collector of switch Q1 is diode D
It is connected via 2 to the connection point between the rectifier 3 and the emitter of the switch Q2.

The collector of the switch Q5 is a diode D
1 is connected to the connection point of the rectifier 3, the emitter is connected to the connection point of the capacitor 15 and the collector of the switch Q2 and the control circuit 26, and the base is connected to the control circuit 26.

The operation of the embodiment thus configured will be described below with reference to the timing chart of FIG. First, the state in which the electric motor 8 is regenerated will be described. In this case, the voltage VDC across the smoothing capacitor 6 rises above the rectified voltage of the normal power supply voltage, that is, the reference voltage VREF. When the voltage detector 14 detects the voltage VDC at both ends and the control circuit 26 determines that the detected value becomes higher than the reference voltage VREF, an ON command is given to the switches Q2 and Q3. Then, the control circuit 26 controls the voltage VDC
Rises further and exceeds the high reference voltage VH, an ON command is given to the switch Q1. Then, a current flows from the smoothing capacitor 6 through the reactor 19 to the capacitor 15. The reactor 19 prevents the inrush current at this time.

When the voltage VDC across the capacitor 15 becomes lower than the high reference voltage VH due to the current flowing into the capacitor 15, the switch Q1 is turned off. When regeneration is still continued in this state, when the voltage VDC across both ends rises again and exceeds the high reference voltage VH, the switch Q1 is turned on again. This operation is repeated while the regenerative state continues.

At this time, the current waveform IC flowing into the capacitor 15 and the both-end voltage VC change as shown in FIG. As described above, when the switch Q1 is repeatedly turned on and off, Q1 is turned on and IC increases, flows into the capacitor 15, and when Q1 is turned off, the reactor 1
Since the current tries to continue flowing in the same direction by 9, the charging current to the capacitor 15 continues through the diode D3 and the switch Q3. In this case, the current decreases. By repeating this operation, the regenerative energy is absorbed in the capacitor 15.

Next, the operation when the electric motor 8 is in the power running mode will be described. In this case, the voltage VDC across the capacitor 6 becomes lower than the reference voltage VREF. When the control circuit 26 judges this from the detection value of the voltage detector 14, the switches Q2 and Q3 are turned off and Q5 and Q6 are turned on. further,
When the control circuit 26 determines that the voltage VDC across both ends has dropped to the low reference voltage VL or less, Q4 turns on. As a result, the capacitor 15 is connected in series between the anode of the rectifier 3 and the smoothing capacitor 6 via the reactor 19, and a current flows from the capacitor 15 to the smoothing capacitor 6. As a result, when the voltage VDC across the smoothing capacitor 6 rises and exceeds the low reference voltage VL, Q
4 is turned off. In this state, if the power running operation is still continued, the voltage VDC across both ends drops to the low reference voltage VL or less, and this operation is repeated again. As a result,
The energy of the condenser 15 flows into the condenser 6.

When the switch Q4 is turned on, the current of the capacitor 15 increases toward the capacitor 6. In this case as well, the inrush current is suppressed by the reactor 19. Further, when the switch Q4 is turned off, a current tends to continue to flow due to the reactor 19, so this current is bypassed through the diode D3 and the switch Q6. In this way, energy flows from the capacitor 15 to the capacitor 6, and the voltage VC across the capacitor 15 decreases as shown in FIG.

FIG. 2 is a diagram for explaining the control circuit 26 described above, which includes fixed resistors 27, 28, 31, and.
32, 34, 36, 39, 40, 51, 52, 56, 5
9, 61, 63, 64, 67, 69, variable resistors 29, 5
7, 65, Zener diodes 30, 58, 66, diodes 35, 47, capacitors 33, 45, inverter elements 43, 71, photocouplers 37, 38, 49, 5
0, 60, 68, and drive power sources 41, 42, 53, 54, 62, 70 for driving the switches Q1 to Q6. The operation of the control circuit 26 having such a configuration will be described.

By setting the resistors 27 and 28 and the variable resistor 29, the above-mentioned reference voltage VREF is set, and when the voltage VDC across the capacitor 6 exceeds this, the Zener diode 30 is set to exceed the Zener voltage to turn on. Has been done. Therefore, when the voltage VDC across the capacitor 6 exceeds the reference voltage VREF, the capacitor 33 is charged through the resistors 31 and 32, and when this is charged, the photocouplers 37 and 38 are passed through the resistor 36. Current flows to the primary side of the switch, the secondary side turns on, and the switches Q2 and Q3 are driven by the drive power sources 41 and 42 to turn on.

At this time, this output is brought to a low (LOW) level by the inverter element 43, the capacitor 45 is discharged through the resistor 46 and the diode 47 to be a LOW level, and the photocouplers 49 and 50 are turned off. The switches Q5 and Q6 are also turned off.

Here, the respective resistance values R34, R46, R32, R44 of the resistors 34, 46, 32, 44 are R
34 = R46 << R32 = R44, the switches Q2, Q3, Q5 and Q6 are turned off earlier and turned on later, so that the switches Q2, Q3 and Q5, Q6 are in an inverted relation. , And an interlock time Δt between them (time when they are not turned on at the same time) Δt are provided so that they are not turned on at the same time.

On the contrary, when the voltage VDC across the capacitor 6 becomes equal to or lower than the reference voltage VREF, the charge charged in the capacitor 33 is discharged through the path of the resistor 34 and the diode 35 and becomes LOW.
Then, the switches Q2 and Q3 are turned off, the output of the inverter element 43 becomes a high (HIGH) level, and the resistor 4
The conden 45 is charged via 4 and Q5 and Q6 are turned on.

On the other hand, the above-mentioned high reference voltage VH is set by setting the resistors 55 and 56 and the variable resistor 57, and when the voltage VDC across the capacitor 6 exceeds this, the Zener diode 58 turns on exceeding the Zener voltage. Is set. Therefore, the voltage across the capacitor 6 VDC
However, if the voltage exceeds the high reference voltage VH, the photocoupler 6
Current flows to the primary side of 0, the secondary side turns on, and switch Q
1 is driven by the driving power supply 62 and turned on.

On the other hand, by setting the resistors 63 and 64 and the variable resistor 65, the above-mentioned low reference voltage VL is set, and when the voltage VDC across the capacitor 6 exceeds this, the Zener diode 66 is turned on exceeding the Zener voltage. Is set. Therefore, the voltage across the capacitor 6 VDC
However, if the voltage exceeds the low reference voltage VL, the inverter 71
The switch Q4 is driven by the drive power source 70 by setting the output of the switch from HIGH to LOW. In this case, when the voltage VDC across the capacitor 6 falls below the low reference voltage VL, the switch Q4 is turned on, and VDC
When the voltage exceeds VL, the switch Q4 is turned off.

According to the embodiment described above, the following effects can be obtained. That is, the energy during regeneration of the electric motor 8 which has not been effectively used until now is stored in the capacitor 15 with a simple configuration, and this is used during power running of the electric motor 8, so that power consumption can be reduced.
For example, if the same effect as in the conventional technique is to be realized only by increasing the capacity of the smoothing capacitor 6,
VREF = 200 × (2) ^{1/2 If the} regenerative energy is set to 1KW by allowing a voltage increase of 50V with V commercial power supply. About 283V and VH = 283 + 50 = 330V. Then, the energy of the capacitor 6 WC = 1 / 2CV ² The more necessary capacitor capacity is C = 2WC / V ² Becomes From now on, C = 2.1 kW / (50) ² = 800mF
Becomes On the other hand, in the case of the present embodiment, since the capacitor 15 can be basically used for charging from the state of 0 V to the high reference voltage VH, the required capacity of the capacitor 6 is

C = 2.1 kW / (333) ² = 18 mF
Therefore, the energy can be absorbed by the capacitor 15 which is significantly smaller than that in the above-mentioned conventional example, which is practical and can be realized at a low cost.

In the above-described embodiment, the reactor 19 prevents the inrush current, but by speeding up the operation of the semiconductor switching element Q2, the reactor 19 can be omitted due to the impedance of the wiring. Further, depending on the situation, the diodes D2 and D3 and the semiconductor switching elements Q3 and Q6 of the above-mentioned embodiment can be omitted.

[0038]

According to the present invention, it is possible to provide a control device for a four-quadrant operation load device which can effectively utilize regenerative energy with a simple structure and reduce power consumption.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a schematic configuration of an embodiment of a control device for a four-quadrant operation load device of the present invention.

FIG. 2 is a circuit diagram showing the control circuit of FIG. 1 in detail.

FIG. 3 is a timing chart for explaining the operation of FIG.

FIG. 4 is a diagram showing an example of a main circuit of a conventional elevator.

[Explanation of Codes] 1 ... Commercial power source, 3 ... Diode rectifier, 6 ... DC smoothing capacitor, 7 ... Inverter bridge, 8 ... Induction motor,
9 ... Reduction gear, 10 ... Main sheave, 12 ... Counter weight, 13 ... Basket, 14 ... Voltage detector, 15 ... Energy absorption capacitor, 19 ... Current suppression reactor, 2
6 ... Control circuit, D1, D2 ... Diodes, Q1-Q5 ...
Semiconductor switches such as IGBT.

Claims (2)

[Claims] 1. A first power converter for converting alternating current to direct current and a second power converter for converting a direct current output of the first power converter to alternating current and giving it to an electric motor for driving a four-quadrant operating load. And a DC smoothing capacitor connected in parallel to the input side of the second power converter and the output side of the first power converter to smooth the DC output of the first power converter; An energy absorbing capacitor between the smoothing capacitor and the first power converter, which is connected in combination with the DC smoothing capacitor in parallel and in series with a plurality of switching elements, and the DC smoothing capacitor. And a voltage detector that detects the voltage across both ends of the voltage detector, and the energy absorbing capacitor is connected in parallel to the DC smoothing capacitor when the detection value detected by the voltage detector exceeds the reference voltage. The switching element is turned on so that the energy absorbing capacitor is connected in series with the DC smoothing capacitor when the detection value detected by the voltage detector is equal to or lower than the reference voltage. A control device for a four-quadrant operation load device, comprising a control circuit for giving a command. 2. A first power converter for converting AC to DC, and a second power converter for converting a DC output of the first power converter to AC and supplying the motor to drive a four-quadrant operation load. And a DC smoothing capacitor connected in parallel to the input side of the second power converter and the output side of the first power converter to smooth the DC output of the first power converter; An energy absorbing capacitor between the smoothing capacitor and the first power converter, which is connected in combination with the DC smoothing capacitor in parallel and in series with a plurality of switching elements, and the DC smoothing capacitor. And a voltage detector that detects the voltage across both ends of the voltage detector, and the energy absorbing capacitor is connected in parallel to the DC smoothing capacitor when the detection value detected by the voltage detector exceeds the reference voltage. As described above, the switching element is intermittently given an ON command, and when the detection value detected by the voltage detector is equal to or lower than a reference voltage, the energy absorbing capacitor is connected in series with the DC smoothing capacitor. A control device for a four-quadrant operation load device, comprising: a control circuit which intermittently gives an ON command to an element.