JP4428049B2 - Backup method and apparatus for DC power supply for inverter in elevator - Google Patents

Description

  The present invention relates to an elevator control device that drives an electric motor by a voltage source inverter, and more particularly to a control method and a control device for an emergency power device that is provided as a power source for an inverter during a power failure.

FIG. 7 shows a configuration example of the elevator control device. The elevator control device includes an emergency power device for supplying DC power to the inverter during a power failure. The simplest configuration of an emergency power device is one that connects a storage battery to an inverter DC bus via a magnet contactor switch. However, there is a drawback in that the elevator apparatus becomes a power failure during the switching period to the storage battery for emergency power supply due to a power failure, and the operating elevator stops (continuous operation cannot be continued).
By the way, about the inverter for elevators of a small and medium capacity model, the regenerative energy from a motor is thermally consumed using a discharge resistance. In recent years, the energy recycling problem has attracted attention. As proposals for solving this problem, Patent Literature 1 and Non-Patent Literature 1 are publicly known.

  The thing of patent document 1 is storing the regenerative power in an emergency power device and reusing it, and this emergency power device has a step-up / step-down chopper circuit and not only functions as a backup power source in the event of a power failure but also regenerative power. The power storage function is added. And by the step-up / step-down chopper operation, an emergency power device can be configured with a small number of batteries.

  FIG. 8 shows a power failure control circuit of the elevator control device of Patent Document 1. As a main circuit configuration, a storage battery B is connected via a DC-DC conversion circuit 8 to a rectifier 1 that rectifies AC power and converts it to DC power, and a DC bus between inverters 2 that converts DC power to AC power. ing. The DC-DC conversion circuit 8 is composed of a bidirectional step-up / step-down chopper, can charge the storage battery and discharge from the storage battery, and when the electric power is regenerated from the motor 3 during the elevator operation, The chopper circuit is operated to store energy in the storage battery. The accumulated energy is reused by discharging the accumulated power when a power failure occurs or when the input power supply is reduced. Conventionally, in medium-capacity elevator models, the regenerative energy from the motor is entirely consumed by the resistance for regenerative discharge, and about half of the elevator operation is regenerative operation, which has a considerable energy saving effect.

In the apparatus shown in FIG. 8, the charge / discharge switching method is performed as follows.
Based on the DC bus voltage calculated from the three-phase AC power supply voltage when the inverter 2 is in a no-load state, whether the current DC voltage is larger or smaller than the reference voltage, the motor operation is in a driving state or regenerative Determine if it is in a state. Based on the determination result, the charge / discharge operation is switched. That is, when the DC bus voltage is higher than the reference voltage, the step-down chopper circuit is operated to charge the storage battery. When the DC bus voltage is lower than the reference voltage, the boost chopper circuit is operated to discharge the storage battery. When a power failure occurs, the DC voltage drops as the stored energy of the main electrolytic capacitor C decreases. However, when the DC bus voltage is lower than the reference voltage, the storage battery B is discharged via the DC-DC converter 8, so that the inverter operation does not stop due to a DC voltage drop failure or the like even during a power failure.
Here, it is not necessary to determine whether the cause of the DC voltage drop is due to the power running operation of the motor or due to the occurrence of a power failure.

The non-patent document 1 is configured as shown in FIG. 9, and the circuit configuration of the emergency power device adopts the method of Patent Document 1, but the charge control method for storing the regenerative power of the inverter in the emergency power device In addition, there has been proposed a discharge control method and the like for supplying the stored electric power to the inverter even during normal operation of the elevator.
That is, this apparatus calculates the amount of electric power necessary for operation from the elevator controller 7 (or inverter), and gives an electric power command to the charge / discharge circuit of the step-up / down chopper.
JP-A 61-267675 "Mitsubishi Electric Technical Bulletin" issued by Mitsubishi Electric, Vol. No. 12, 2001, p.22-25

  In the method of FIGS. 8 and 9, since charging / discharging is frequently performed between the storage battery B and the inverter 2 via the DC-DC converter 8, the storage battery is not always fully charged when a power failure occurs. For this reason, the elevator operation during a power failure may be performed only for a short time.

  Therefore, an object of the present invention is to provide an emergency power device that supplies power to the inverter only during a power failure and charges a storage battery during commercial power reception in order to ensure long-time operation during a power failure and its control. It is to provide a method.

The first of the present invention is a forward converter for converting the power of the AC power source to DC, a smoothing electrolytic capacitor connected between the converted DC buses, and converting DC to a variable AC voltage at a variable frequency. DC-DC converter comprising an inverter having an inverse conversion unit for output to an elevator motor, a bidirectional step-up / step-down chopper connected between the DC buses of the inverter, and a storage battery connected via the converter And supplying emergency power stored in the storage battery to the motor via the inverter based on the command of the charge / discharge control circuit during a power failure,
It means for detecting said power failure, a power failure detector for monitoring the power recovery voltage drop of the alternating current power supply, the two means of the power failure power calculator for calculating power in case of power failure by introducing a dc bus voltage Providing a gate signal for starting discharge to the DC-DC converter via the charge / discharge control circuit based on the power failure determination of any one of the power failure detection means, and at the time of power recovery, the power failure detector In addition to using the detection signal to stop the discharge operation of the charge / discharge control circuit, the power calculator at the time of power failure estimates and calculates the power consumption of the inverter from the electrolytic capacitor capacity and the time drop of the DC bus voltage measurement value. Calculates the initial discharge current value of the storage battery from the power value and storage battery voltage, and outputs a discharge start gate signal
However, the power failure detection level for starting discharge is assumed to be the minimum power supply voltage considering the power supply fluctuation and the voltage drop due to power supply impedance, and is set to a voltage value lower than the DC bus voltage. is there.

According to a second aspect of the present invention, the power consumption estimation of the inverter in the power failure time calculator uses a signal sampled at a predetermined time interval, and P = (1/2) C (Vd1 ² −Vd2 ² ). It is characterized by calculating.
However, P (W); Inverter Power + inverter loss, C (F); electrolytic capacitor capacity, Vd1 (V), Vd2 ( V); a third electrolytic capacitor voltage present invention at each sampling time point, the The initial discharge current value is obtained by dividing the obtained power consumption value of the inverter by the storage battery voltage.

A fourth aspect of the present invention is a forward converter for converting AC power to DC, a smoothing electrolytic capacitor connected between the converted DC buses, and an elevator for converting DC to variable AC voltage at a variable frequency. And an emergency power device connected to the DC bus, and this emergency power device is a DC-- consisting of a bidirectional buck-boost chopper connected between the DC buses. In a DC converter, a storage battery and a charge / discharge control circuit connected via this converter, and supplying emergency power stored in the storage battery during a power failure to the motor via the inverter,
A power failure detector that monitors voltage drop and power recovery of an AC power supply to the emergency power device, a power failure power calculator that calculates power by introducing the DC bus voltage, and power calculated by the calculator A voltage regulator that generates a discharge current command value by introducing a dividing means that divides the value by a storage battery voltage detection value to obtain an initial current command, a deviation signal between a DC bus voltage value and a discharge voltage command, and the initial current command And a current regulator for introducing a deviation signal between the discharge current command value and the storage battery current detection value, and a discharge gate signal is generated based on the output signal of the current regulator and output to the DC-DC converter. It is characterized by comprising.

A fifth aspect of the present invention is characterized in that a limiter unit for limiting a discharge current is provided on the output side of the voltage regulator.

According to a sixth aspect of the present invention, the storage battery is a lead storage battery, a deviation signal between the voltage command at the time of constant voltage charging and the storage battery voltage detection value is introduced into a voltage regulator to generate a charging current command value. And a storage battery current detection value are output to a current regulator.

According to a seventh aspect of the present invention, the storage battery is a nickel metal hydride storage battery, and a deviation signal between the charge stop voltage level value and the storage battery voltage detection value is introduced into a voltage regulator to generate a charging current command value. A deviation signal from the storage battery current detection value is configured to be output to a current regulator.

According to an eighth aspect of the present invention, the voltage regulator is provided with a limiter unit for limiting a charging current.

The present invention has the following effects.
(1) According to the emergency power device according to the present invention, when the inverter power supply is healthy, the battery is always charged and the charge amount is maintained in the full state, so that the operation time during the power failure of the elevator can be made as long as possible.
(2) Conventionally, even when no power outage occurs, the battery is charged and discharged from the battery. Therefore, the applied battery requires a nickel-metal hydride battery or the like having a long life depending on the number of times of charge and discharge. Become. In the present invention, the discharge from the storage battery is only at the time of a power failure, and since the number of times of charging / discharging is very small, it is possible to sufficiently apply a lead storage battery that has a short storage battery life but is inexpensive and easy to handle. .
(3) Generally, a method of directly monitoring the power supply voltage is adopted as a power failure detection method for an AC power supply. In this case, since a time of about one cycle period of the power supply frequency is required to determine the power failure, a delay time from the occurrence of the power failure to the detection of the power failure may be a problem.
In the present invention, in addition to the method of detecting a voltage drop of the AC power supply and determining a power failure, a method for determining that a power failure has been detected even when the DC bus voltage falls below a preset voltage level is provided. You can measure the bus voltage directly. Thereby, for example, even when the DC bus voltage drops suddenly when a power outage occurs in the maximum load state in the power running operation of the inverter, the power outage is detected prior to the voltage reduction method of the conventional AC power supply, Since power can be supplied to the inverter in a shorter time, the elevator can be reliably continued even when a power failure occurs during operation.
(4) When a power failure occurs, the power failure detection level is set to a voltage value lower than the DC bus voltage, assuming the minimum power supply voltage considering the power supply fluctuation and the voltage drop due to the power supply impedance. In spite of this, it is possible to prevent an unnecessary discharging operation of the storage battery that is executed, and to prevent the deterioration of the life of the storage battery due to repeated charging and discharging operations.
(5) At the start of discharge control, the initial command value of the discharge current is calculated by the power calculator at the time of power failure using the DC bus voltage as the input value, and this is the integral term initial value in the voltage regulator and the initial output of the voltage regulator. With the function given as a feed-forward term as a value, the discharge current response at the start of discharge can be increased, and the power supplied to the inverter can be made to respond in a shorter time.
(6) Since the inverter power in the above function is estimated by the device itself using the equation (1) from the amount of DC bus voltage drop and the electrolytic capacitor capacity connected to the DC bus voltage, the inverter control circuit and controller Since it is not necessary to input power information, the configuration as an emergency power device system is simplified.
(7) The discharge current limited by the storage battery capacity can be easily limited to a desired current value or less by limiting the voltage regulator output and the integral term in the voltage regulator with the limit value. .

In addition to the effects described above, the storage battery is charged in the lead storage battery (second embodiment).
(8) The voltage regulator integral term and output current command value are limited by the limit current value at the time of constant current charging of the lead storage battery, and the voltage value at the time of constant voltage charging of the storage battery is used as the voltage command value of the voltage regulator input section. By giving, the control system automatically determines whether it is constant current charge or constant voltage charge. Therefore, simple charge control of the lead storage battery is possible.
(9) The charge control circuit of (8) can also be used for charging a nickel metal hydride storage battery.

FIG. 1 is a block diagram showing a first embodiment of the present invention, in which 10 is a voltage source inverter and 20 is a power supply for power failure during an elevator (hereinafter referred to as an emergency power device).
The inverter 10 includes a forward conversion unit 11 including a rectifier or a three-phase PWM converter that converts an AC power source into a direct current, an inverse conversion unit 12 that converts a direct current into a variable alternating voltage at a variable frequency in order to drive an electric motor, and the forward conversion. A large capacity electrolytic capacitor 13 and a regenerative power discharge circuit 14 are connected to the DC buses of the unit 11 and the reverse conversion unit 12 for smoothing. The emergency power device 20 includes a bidirectional DC-DC converter 21 having both a step-up chopper function and a step-down chopper function, a power storage device 22 for storing emergency power during a power failure, a charge / discharge control circuit 23, a DC bus voltage. And a power failure detector 25 and a power failure detector 25.
3 is an elevator motor, and 4 is an encoder, which detects the speed of the motor and feeds it back to the inverter control circuit 6. Reference numeral 5 denotes a gate drive circuit of the inverse converter 12 , and 7 denotes an elevator controller.

  The DC-DC converter 21 includes power semiconductor switches Tr1 and Tr2, such as power transistors and IGBTs, a DC reactor DCL, and a battery current detector CT. As the power storage device 22 in which the emergency power is stored, a large capacity capacitor such as a storage battery or an electric double layer capacitor is used, and the voltage of the power storage device 22 is a step-up and step-down function of the bidirectional DC-DC converter 21. Is used at a voltage lower than the DC bus voltage. Here, an example in which a secondary battery such as a lead battery or a nickel metal hydride battery is used for the power storage device will be described.

The emergency power device configured as described above is
(1) Boosting the storage battery voltage at the time of power failure and supplying DC power to the inverter to enable the elevator to operate at the time of power failure.
(2) Even if a power failure occurs during the elevator operation, the above-described DC power supply is performed at a high speed so that the operation can be continued.
(3) The storage battery is charged from the commercial power supply of the inverter so that the amount of stored electricity at the time of power failure always becomes maximum, and the operation time at the time of power failure of the elevator is made as long as possible. That is, the stored energy is used only for the power supply during a power failure.
Therefore, in the present invention, whether to execute discharge control and charge control is determined based on whether or not a power failure occurs.
Generally, a method of directly monitoring the power supply voltage is adopted as a method of detecting a power failure of an AC power supply. However, since it takes a time of about one cycle period of the power supply frequency to determine a power failure, a power failure is detected from the occurrence of the power failure. The delay time may become a problem. As an example of a problem due to a power failure detection delay time, for example, if a power failure occurs when the inverter is operating at a maximum load, the delay control delays the start of the discharge control of the DC-DC converter 21, and the DC bus voltage Drops suddenly, leading to inverter DC voltage drop failure. Alternatively, even if the discharge control is started before the inverter reaches the DC voltage drop failure, if the state in which the power supply to the inverter cannot follow the inverter power consumption continues due to the delay in the response of the discharge control, the bus voltage Descends and eventually stops the elevator.

In view of the above, the present invention solves the following problems.
(A) The time from when a power failure occurs until the present apparatus detects the power failure and starts the discharge control of the storage battery is made as short as possible.
(B) To shorten the rise time to the current value required by the inverter when a power failure occurs, the control response of the discharge current at the start of discharge is increased.
First, as a solution of the item (a), in addition to the conventional power failure detection method by measuring the voltage of the AC power supply, the present invention is provided with a power failure detection method by providing a power calculator 24 at the time of power failure and measuring the DC bus voltage. Yes. During commercial power reception of the inverter, the DC bus voltage is constantly measured at a high sampling rate, and when the voltage value drops to a predetermined voltage level, it is assumed that a power failure has occurred and discharge control is immediately started. However, as will be described later, a method for determining power recovery uses means based on voltage measurement of an AC power supply.

An example of a power failure detection method of the present invention will be described with reference to FIG. 2 showing an operation chart of each part when a power failure occurs during powering operation of an elevator.
FIG. 2 shows the phenomenon on the vertical axis and the time t on the horizontal axis. When a power failure occurs at time t1 during the power running operation of the inverter, the DC bus voltage Vinv drops with a slope determined by the load state of the inverter and the capacity of the electrolytic capacitor connected to the DC bus.
At time t2 when the DC bus voltage Vinv falls below a preset power failure detection level Vdchg, the charge / discharge control circuit 23 determines that a power failure has occurred and outputs an on / off discharge gate signal to the semiconductor switch Tr2. The discharge control of the storage battery 22 is started. Until the power failure is determined, the charging control is performed by the control of the semiconductor switch Tr1 by the on / off charging gate signal.

The power outage detection level Vdchg assumes the minimum power supply voltage considering the power supply fluctuation and the voltage drop due to the power supply impedance in order to prevent the erroneous determination of the power outage due to the DC voltage drop due to the power supply drop during commercial power reception, etc. Is set to a voltage value lower than the DC bus voltage obtained by three-phase full-wave rectification. Thereby, unnecessary storage battery discharge is prevented, and deterioration of the life of the storage battery due to repeated charge and discharge operations is prevented.
Further, since the power failure detection level Vdchg is a DC voltage at the start of discharge, it must be set to a voltage level higher than the DC voltage drop failure level Vuvt of the inverter.
At the same time that the power failure is detected by the above-described method, the charge / discharge control circuit 23 starts the discharge control and simultaneously outputs a power failure detection signal to the elevator controller 7. When the controller 7 receives the signal, the controller 7 changes the elevator speed command signal given to the inverter control circuit 6 to a low speed at the time of a power failure to reduce the motor power and reduce the supply power (discharge current) of the emergency power device.

Next, as a solution of the item (b), a specific discharge control flock diagram at the time of a power failure will be described with reference to FIG.
Basically, voltage control is performed so that the DC bus voltage of the discharge control inverter becomes a constant voltage, and a current minor loop (ACR control) is provided inside to stabilize the discharge current. In FIG. 3, reference numeral 23-1 denotes an adder. The discharge voltage command value and the DC bus voltage detection value are applied to the adder with opposite polarities, and a deviation between the two is obtained. The deviation is applied to the voltage regulator 23-2. The inputted P1 calculation is performed. At the time of starting the discharge control, the power calculator 24 at the time of power failure using the DC bus voltage as an input value calculates the inverter power consumption at the time of the power failure from the DC voltage drop amount and the capacity of the main electrolytic capacitor 13, and the power command to the inverter The value is output to the division unit 23-3. In this division unit, the power command value divided by the storage battery voltage is the discharge current command value, which is given as the integral term initial value in the voltage regulator and the initial output value of the voltage regulator.

The output of the voltage regulator becomes a discharge current command value, which is applied to the addition unit 23-5 via the limiter unit 23-4, and the deviation between the discharge current command value obtained in this addition unit and the storage battery current detection value is the current regulator. 23-1 and P1 is calculated. The output of the current regulator is a voltage command signal to the DC-DC converter 21 and is input to the PWM signal circuit 23-7 and subjected to PWM modulation. Based on this modulation signal, the gate signal of the semiconductor switch Tr2 for discharge is obtained. . This gate signal is applied to the gate of the semiconductor switch Tr2 via the gate drive circuit 23-8, and thus DC power is supplied while controlling the discharge current and the DC bus voltage.
The discharge current is limited by the storage battery capacity from the storage battery protection surface. By limiting the discharge current command value, that is, the voltage regulator output and the integral term in the voltage regulator with the limit value so as not to exceed the limit value, the discharge current can be limited to a desired current value or less.

In general, the power consumption of the inverter can be calculated by the inverter control circuit 6 or the elevator controller 7. However, in the inverter power calculation method according to the present invention, the power consumption of the inverter is estimated using the equation (1) from the amount of drop in the DC bus voltage and the electrolytic capacitor capacity connected to the DC bus voltage. Can be calculated on the side. A detailed calculation method will be described with reference to FIG.
P = (1/2) C (Vd1 ² −Vd2 ² ) (1)
Here, P (W): Inverter power consumption, C (F): Electrolytic capacitor capacity, Vd1 (V): Electrolytic capacitor voltage at time t11, Vd2 (V): Voltage capacitor voltage at time t12 (where t12 > t11 )
Formula (1) is established only when inverter power is consumed only by the energy stored in the electrolytic capacitor due to the occurrence of a power failure, and is calculated by Formula (1) under the condition that the inverter is operated with a commercial power source. The power does not reflect actual inverter power. However, if the DC bus voltage is near the discharge start level, the inverter can be regarded as a power failure state. Therefore, when the DC bus voltage drops to near the power failure detection level, this is an effective means for estimating the inverter power consumption according to equation (1). At the time of commercial power reception of the inverter, the inverter power is estimated by using the power voltage calculator 24 at the time of a power failure using the bus voltage measurement value (1).

T11 and t12 shown in FIG. 4 are sample periods of power calculation in the power calculator 24 at the time of power failure, and P represents inverter average power between time t11 and time t12. As for the sampling period of power calculation, it is necessary to pay attention to the analog detection accuracy of the DC bus voltage and the AD converter accuracy for taking the signal into the CPU. However, the higher the accuracy, the faster the sampling period.
At the start of discharge due to a power failure, the current obtained by dividing the inverter power calculated immediately before the start of discharge by the storage battery voltage measurement value is used as the initial value of the discharge current command value. The current command value is given as an initial value of the integral term of the voltage regulator at the start of discharge control, whereby the voltage regulator at the start of discharge immediately outputs a discharge current command to be supplied to the inverter. be able to. Compared with the case where the above method is not used, the time until the voltage regulator output reaches a desired discharge current command can be shortened, so that the control response at the time of discharge can be increased.

Next, a case where a power failure occurs during the regenerative operation of the elevator will be described.
In the event of a power failure, the DC bus voltage rises due to regenerative energy from the motor, so the power failure cannot be detected by the method described above. At this time, the inverter can also continue the operation while consuming the regenerative energy from the electric motor by the regenerative power discharge circuit 14. Therefore, in the present invention, even when a power failure is not detected by monitoring the DC bus voltage, even when a power failure determination is made due to a decrease in the power supply voltage value in the power failure detection circuit 25 of FIG. Simultaneously with starting the discharge control, a power failure detection signal is output to the elevator controller 7 so that the elevator controller shifts to a power failure control operation. In the discharge control of the present apparatus when the inverter is in the regenerative operation state as in the above condition, almost no power is supplied to the inverter, and power supply is required at the time of landing on the elevator.

Next, the power recovery detection method of the device of the present invention will be described.
The power failure detection method is performed by monitoring the DC bus voltage drop or the power supply voltage drop. However, the power recovery cannot be detected by the DC bus voltage monitoring method. One of the reasons is that the DC bus voltage is controlled to be constant during discharging. Another reason is that the DC bus voltage when the elevator is in regenerative operation rises to the operating voltage level of the regenerative power discharge circuit due to resistance. Therefore, for power recovery detection, power recovery detection is performed only by the power failure detector 25 that measures the voltage of the commercial power supply. When power recovery is detected, the emergency power device 20 stops discharging the storage battery 22 and shifts to a charging operation.

FIG. 5 shows a charge control block diagram of the lead storage battery according to the second embodiment.
When the storage battery 22 is a lead storage battery, the charge / discharge control circuit 23 in the emergency power device 20 has the function shown in FIG. 5 and performs the following charge control.
Although the basic control configuration is the same as the discharge control, a voltage control loop for making the storage battery voltage constant is provided, and a current minor loop (ACR control) is provided inside to control the charging current. The voltage command value at the time of constant voltage charging and the storage battery voltage detection value are introduced into the adding unit 23′-1 to obtain a deviation between them, and this deviation is input to the voltage regulator 23′-2 to calculate P1. Next, the output value is used as a charging current command value for the storage battery current, and the adder 23-5 obtains a deviation from the detected storage battery current value and inputs it to the current regulator 23-6 to calculate P1. The output signal of the current regulator is a voltage command signal to the DC-DC converter 21 and is input to the PWM signal circuit 23-7. A gate signal of the semiconductor switch Tr1 is obtained by PWM modulation. This gate signal is output to the gate of the semiconductor switch Tr1 through the gate drive circuit 23-8 and charged while controlling the current and voltage of the storage battery.

  The integral term and the output current command value of the voltage regulator 23'-2 are controlled by using the allowable charging current value of the lead storage battery so that the charging current does not exceed the allowable charging current value of the storage battery. When the charging state is limited by the limit value in the limiter 23'-4, a steady deviation occurs between the voltage command signal and the voltage feedback signal input to the voltage regulator 23'-2. In such a charged state, the storage battery is charged with a constant current. Further, as the charging proceeds, the storage battery voltage increases, so that the input deviation of the voltage regulator gradually decreases and the voltage regulator output also decreases, and the charging current command value is controlled to be equal to or less than the limit value. As described above, since the switching from the constant current charging to the constant voltage charging control and the reverse control switching are automatically performed, the control method becomes simple.

FIG. 6 shows a charge control block diagram of the nickel metal hydride storage battery according to the third embodiment.
When a nickel metal hydride battery is used as the storage battery 22, the battery is charged with a constant current until the battery is fully charged, unlike the lead-acid battery charging method. The determination of full charge is generally made by measuring the temperature rise value or voltage change amount of the storage battery per unit time. The charge control circuit for the nickel hydride storage battery is configured based on the charge control circuit for the lead storage battery in FIG. 5, and the charge current command value for the storage battery rating is used as the integral term of the voltage regulator and the limit value of its output value. Further, by giving a charge stop voltage value of the storage battery as a voltage command value of the voltage regulator input, it is possible to perform charge control with a constant current and to prevent overvoltage charge to be careful in the constant current charge method.

Configuration diagram showing an embodiment of the present invention Operation chart at power failure Functional block diagram of discharge control in emergency power equipment Illustration of how to estimate inverter power Lead storage battery charge control function block diagram NiMH battery charge control function block diagram Elevator control system configuration diagram Configuration diagram of a conventional elevator control device Configuration diagram of a conventional elevator control device

Explanation of symbols

1,11 ... Forward converter
2,12 ... Inverter
3 ... Motor
4 ... Encoder
5 ... Gate drive circuit
6 ... Inverter control circuit
7 ... Elevator controller
10 ... Inverter
13 ... Electrolytic capacitor
20 ... Emergency power device
21 ... DC-DC converter
22 ... Storage battery
23 ... Charge / discharge control circuit 24 ... Power calculator at power failure
25 ... Power failure detector

Claims (8)

A forward converter for converting the power of the AC power source into DC, a smoothing electrolytic capacitor connected between the converted DC buses, and converting the DC to a variable AC voltage at a variable frequency and outputting it to an elevator motor A DC-DC converter composed of an inverter having an inverse converter and a bidirectional step-up / step-down chopper connected between the DC buses of the inverter and a storage battery connected via the converter are charged and discharged during a power failure. In what supplies the emergency power stored in the storage battery to the motor via the inverter based on the command of the control circuit,
It means for detecting said power failure, a power failure detector for monitoring the power recovery voltage drop of the alternating current power supply, the two means of the power failure power calculator for calculating power in case of power failure by introducing a dc bus voltage Providing a gate signal for starting discharge to the DC-DC converter via the charge / discharge control circuit based on the power failure determination of any one of the power failure detection means, and at the time of power recovery, the power failure detector In addition to using the detection signal to stop the discharge operation of the charge / discharge control circuit, the power calculator at the time of power failure estimates and calculates the power consumption of the inverter from the electrolytic capacitor capacity and the time drop of the DC bus voltage measurement value. The initial discharge current value of the storage battery is calculated from the power value and the storage battery voltage, and a discharge start gate signal is output.
The power failure detection level for the start of discharge is assumed to be the minimum power supply voltage considering the power supply fluctuation and the voltage drop due to the power supply impedance, and is set to a voltage value lower than the DC bus voltage. A backup method for a DC power supply for an inverter in the apparatus. The power consumption estimation of the inverter in the power failure power calculator is calculated by P = (1/2) C (Vd1 ² −Vd2 ² ) using a signal sampled at a predetermined time interval. The backup method of the DC power supply for inverters in the elevator of Claim 1 .
Where P (W): inverter power consumption + inverter loss, C (F); electrolytic capacitor capacity, Vd1 (V), Vd2 (V); electrolytic capacitor voltage at each sampling time 3. The backup DC power source for an inverter in an elevator according to claim 1, wherein the initial discharge current value is obtained by dividing the obtained power consumption value of the inverter by a storage battery voltage . Forward converter that converts AC power to DC, smoothing electrolytic capacitor connected between the converted DC buses, and reverse conversion that converts DC to variable AC voltage at a variable frequency and outputs it to an elevator motor And an emergency power device connected to the DC bus, the emergency power device is a DC-DC converter comprising a bidirectional step-up / step-down chopper connected between the DC buses, and this conversion In the case of providing a storage battery and a charge / discharge control circuit connected via a battery, and supplying emergency power stored in the storage battery during a power failure to the motor via the inverter,
A power failure detector that monitors voltage drop and power recovery of an AC power supply to the emergency power device, a power failure power calculator that calculates power by introducing the DC bus voltage, and power calculated by the calculator A voltage regulator that generates a discharge current command value by introducing a dividing means that divides the value by a storage battery voltage detection value to obtain an initial current command, a deviation signal between a DC bus voltage value and a discharge voltage command, and the initial current command And a current regulator for introducing a deviation signal between the discharge current command value and the storage battery current detection value, and a discharge gate signal is generated based on the output signal of the current regulator and output to the DC-DC converter. A backup device for a DC power supply for an inverter in an elevator characterized by being configured. 5. The backup apparatus for an inverter DC power supply in an elevator according to claim 4, further comprising a limiter unit for limiting a discharge current on an output side of the voltage regulator . The storage battery is a lead storage battery, a deviation signal between a voltage command at the time of constant voltage charging and a storage battery voltage detection value is introduced into a voltage regulator to generate a charging current command value, and the charging current command value and the storage battery current detection value are 6. The backup apparatus for an inverter DC power source in an elevator according to claim 4, wherein the deviation signal is output to a current regulator . The storage battery is a nickel metal hydride storage battery, a deviation signal between a charge stop voltage level value and a storage battery voltage detection value is introduced into a voltage regulator to generate a charging current command value, and the deviation between the charging current command value and the storage battery current detection value 6. The backup apparatus for an inverter DC power source in an elevator according to claim 4, wherein the signal is output to a current regulator . 8. A backup device for an inverter DC power supply in an elevator according to claim 6, wherein a limiter for limiting a charging current is provided in the voltage regulator .

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