WO2002093730A1

WO2002093730A1 - Charge and discharge control device

Info

Publication number: WO2002093730A1
Application number: PCT/JP2001/003942
Authority: WO
Inventors: Hirokazu Nagura; Ikuo Yamato; Sadao Hokari; Hiromi Inaba
Original assignee: Hitachi, Ltd.
Priority date: 2001-05-11
Filing date: 2001-05-11
Publication date: 2002-11-21
Also published as: CN100533946C; JP4284075B2; JPWO2002093730A1; CN1639958A

Abstract

A charge and discharge control device, wherein S1 used as a switching element for pressure rising and S2 used as a switching element for pressure lowering are turned on and off alternately with a dead time provided therebetween irrespective of whether an electric motor load a powering or regenerating operation is performed, whereby a DC reactor current can be operated continuously at all times, and the discontinuous state of the DC reactor current need not be detected.

Description

Specification

Charge / discharge control device Technical field

The present invention relates to a charge / discharge control device that accompanies a device that drives an electric motor by inversion and performs uninterruptible power control and reuse of regenerative power. Background art

For example, as prior art, there are Japanese Patent Application Laid-Open No. 61-267675 and Japanese Patent Application Laid-Open No. 11-299275.

In these conventional techniques, the voltage of the secondary battery is raised or lowered by determining whether the motor connected in the inverter is running or regenerating. At the time of power supply, the voltage of the secondary battery is boosted to supply power to the input section of the inverter, and at the time of regeneration, the secondary battery is charged with the regenerated power.

In Japanese Patent Application Laid-Open No. 61-2676775, an input voltage value of an inverter is detected, and power running and regeneration of a motor are determined based on a magnitude relationship with a predetermined value. In Japanese Patent Application Laid-Open No. H11-1299275, the voltage and the current on the input side of the inverter are detected and multiplied by them to determine the power regeneration of the motor. Disclosure of the invention

FIG. 2 shows a charge / discharge control device when the present invention is not used.

The charge / discharge control device shown in FIG. 2 is a step-up chopper that performs step-up control of the step-up switching element S 1 while the step-down switching element S 2 is turned off when the motor 6 is in operation. Operation raises the voltage of secondary battery 8 To supply power to the DC input section of the inverter 3. Further, when the motor 6 is in regenerative operation, the step-down chopper operation for controlling the step-down switching element S2 while the step-up switching element S2 is in the off-state while the step-up switching element S1 is kept off causes the DC of the inverter 3 The voltage of the input section is reduced to charge the secondary battery 8. Such a charge / discharge control device determines whether the charge / discharge control device is to be operated by a step-up or a step-down discharge operation by constantly determining whether the motor load is in a running operation or a regenerative operation. A means for determining is required.

In addition, since the above-mentioned charge / discharge control device performs a booster operation or a step-down operation according to the charging / discharging of the secondary battery 8, especially when the current flowing to the motor is small, the DC reactor There is a problem that the current flowing through the device becomes discontinuous and the control characteristics deteriorate. This is shown in FIG. In FIG. 3, IL represents the current flowing in the DC reactor 7 when the current flowing from the secondary battery 8 is taken in the positive direction. FIG. 3 (a) shows the case where the motor 6 is in the power mode, and the waveform 40 shows the state of continuous current and the waveform 41 shows the state of discontinuous current. At this time, between the conduction ratio d of the switching element S1, the voltage Vdc between the terminals of the smoothing capacitor 5 and the voltage Vbat between the terminals of the secondary battery 8, in the case of continuous current, the equation (1) If the relationship is discontinuous, there is the relationship of equation (2).

Vbat

Vdc = ... (1)

1-d

Vbat ² d ² Tsw

Vdc = + Vbat… (2)

2 I oL

(However, L: DC reactor value, Io: Inverter current value, Tsw: Switching cycle)

On the other hand, Fig. 3 (b) shows the case where the motor 6 is in regenerative mode, 42 indicates continuous current and waveform 43 indicates discontinuous current. At this time, between the conduction ratio d 'of the switching element S2 and the terminal voltage Vdc of the smoothing capacitor 5 and the terminal voltage Vbat of the secondary battery 8, in the case of continuous current, the equation (3) If the relationship is discontinuous, there is the relationship of equation (4).

Vbat

Vdc =… (3)

d '

As shown by the above equations (1) to (4), in the chopper operation, the smoothing of the conduction ratio d or d 'depends on whether the current flowing through the DC reactor 7 is continuous or discontinuous. The relational expression of voltage Vdc between terminals of capacitor 5 is different. Further, even when the current flowing through the DC reactor 7 is discontinuous, the voltage between the terminals of the smoothing capacitor 5 with respect to the conduction ratio d or d 'is different between the case of the step-up chopper operation and the case of the step-down chopper operation. The relational expression of Vdc is completely different. For this reason, in the above-described device, it is determined whether the current flowing in the DC reactor 7 is continuous or discontinuous, and a means for switching the control system according to the result is determined. It is indispensable to judge whether the motor is in operation or regenerative operation, and to switch the booster / down converter according to the result.

Therefore, an object of the present invention is to provide a charge / discharge control device that does not require the determination means and does not require a switching operation with a single control system. One feature of the present invention is that the charge / discharge control device uses S 1 used as a switching element for boosting and S 2 used as a switching element for step-down in a power operation of a motor load. Dead regardless of regenerative operation On / off operation is performed alternately with the time interposed. As a result, the DC reactor current can always be operated continuously, and it is not necessary to detect the discontinuous state of the DC reactor current. Further, regardless of the direction of the DC reactor current, the conduction ratio d of the switching element S1, the voltage Vdc between the terminals of the smoothing capacitor 5, and the voltage Vdc between the terminals of the secondary battery 8 can be expressed by a single equation (5). Since the relational expression with bat can be described, it is not necessary to judge the regeneration of power.

V ba t

V d c =-(5)

-brief description of the d drawing

FIG. 1 is a configuration diagram of a charge / discharge control device showing a first embodiment of the present invention. FIG. 2 is a configuration diagram of a charge / discharge control device when the present invention is not used. FIG. 3 is a waveform diagram of a DC reactor current in the charge / discharge control device shown in FIG. FIG. 4 is a comparison diagram of V dc voltage control characteristics in the charge / discharge control devices shown in FIGS. 1 and 2. FIG. 5 is a diagram illustrating a circuit operation according to the present invention. FIG. 6 is an operation flowchart of the control circuit 21 according to the first embodiment of the present invention. FIG. 7 is a diagram showing a power failure detection means and a motor current detection means in the present invention. FIG. 8 is a diagram showing a constant voltage control system of the V dc voltage in the present invention. FIG. 9 is a diagram for explaining the PWM generation means in the present invention. FIG. 10 is a diagram of a second embodiment in which the present invention is applied to a primary battery system. FIG. 11 is a diagram of a third embodiment in which the present invention is applied to an elevator system. FIG. 12 is a diagram of a third embodiment in which the present invention is applied to an elevator system. Fig. 13 shows another embodiment of the operation of the step-up switching element and the step-down switching element in the charge / discharge control device. It is a figure showing a state.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a charge / discharge control device showing a first embodiment of the present invention.

In FIG. 1, 1 is an AC power supply, 2 is a diode bridge connected to the AC power supply 1 and converts alternating current into a DC voltage, 5 is a smoothing capacitor for smoothing the output voltage of the diode bridge 2, and 4 is a smoothing capacitor. Brake circuit that prevents overvoltage of capacitor 5, 12 is a voltage detector that detects the voltage between terminals of smoothing capacitor 5, 3 is connected to the AC side of diode bridge 2 via smoothing capacitor 5, and converts DC to AC 6 is a motor connected to the AC side of the inverter 3 and driven by the inverter 3, 100 is a bidirectional buck-boost circuit, 8 is a secondary battery, 7 is a DC reactor, 3 1 and 3 2 are switching elements, D 1 and D 2 are diodes, 9 is a gate drive circuit for driving switching element S 1, 10 is a gate drive circuit for driving switching element S 2, 1 1 Is the AC power supply 1 is a voltage detector for detecting a power failure, 13 is a current detector for detecting the current of the motor 6, 20 is a current detector for detecting the current of the DC reactor 7, and 2 is a current detector. This is a control circuit that controls the entire charge and discharge control device.

In the above configuration, when the AC power supply 1 has a power failure, a power failure detection circuit described later issues a power failure detection signal to the microcomputer on the control circuit 21 based on the signal of the voltage detector 11. Upon receiving the power failure detection signal, the above-described microcomputer starts the duty ratio control of the switching elements S 1 and S 2 in order to control the voltage Vdc between terminals of the smoothing capacitor 5 at a constant voltage. This allows Even if the AC power supply 1 fails, the motor 6 can continue normal operation.

If the AC power supply 1 is normal, the motor 6 is in an operating state.If a motor current detection circuit described later detects that the remaining amount of the secondary battery 8 is The voltage control between the terminals of the smoothing capacitor 5 is performed in the same manner as at the time. At this time, by setting the voltage command value of the smoothing capacitor terminal voltage Vdc to a value higher than the voltage value obtained by diode-rectifying the AC power supply 1 described above, the diode bridge 2 is brought into a reverse bias state, and the AC power supply 1 Cut off the current that flows into the DC input section of Room 3 through the diode bridge from. As a result, when the motor 6 operates in the power mode, all the power required for driving the motor is supplied from the secondary battery 8. Conversely, when the electric motor 6 performs the regenerative operation, all of the regenerative electric power is charged in the secondary battery 8. By performing the above operations, the power stored in the secondary battery during regeneration will be actively used during power generation, resulting in an energy saving effect.

Next, the operation principle of the present invention will be described with reference to FIG.

FIG. 5 (a) is a diagram in which only the main circuit portion of the charge / discharge control device is taken out. In this figure, 60 represents the inverter and the motor in FIG. 1 as current source loads. IL is the current flowing in DC reactor 7, Isi is the current flowing in switching element S1, Is2 is the current flowing in switching element S2, and Id1 is the current flowing in diode D1. I d2 represents the current flowing through the diode D 2. Fig. 5 (b) shows the current waveform of each part in the circuit of Fig. 5 (a) together with the switching pattern when the load current Io is near zero. In this figure, Tsw indicates the switching period, Td indicates the on time of the switching element SI, and has a relation of Td = dXTsw with respect to the conduction ratio d. As can be seen from the IL current waveform of waveform 63, in this method, the IL does not become discontinuous even when the load current is near zero. This is because the switching elements S1 and S2 are alternately turned on / off, and there is no mode in which the direction of the reactor current is restricted by the diode as in the conventional method. Furthermore, since the output voltage V dc can be described by a single equation (5) regardless of the direction of IL, there is no need for a means for determining power regeneration.

FIG. 4 is an example showing the difference in control characteristics between the device shown in FIG. 1 and the device shown in FIG. In FIG. 4, a graph 50 shows a characteristic of the output voltage Vdc with respect to the load current when the step-up chopper control is performed at a constant value of the conduction ratio d = 0.5 in the conventional method. Graph 51 shows the characteristics of the output voltage Vdc with respect to the load current when the step-down chopper control is performed at a constant value of the conduction ratio d = 0.5 in the conventional method. From these graphs, it can be seen that in the conventional method, the control characteristics are discontinuous at the point where the load current I o is zero. On the other hand, according to the present invention, it can be seen that the characteristic at the time of the conduction ratio d = 0.5 is a continuous and constant value irrespective of the load current οο as shown in a graph 52.

Next, the operation of the control circuit 21 will be described using the flowchart of FIG.

Fig. 6 shows a sequence in which control of the V dc voltage is started based on the presence or absence of the motor current.When the motor stops, the switching of S1 and S2 is stopped to suppress the circuit loss due to switching. are doing. In FIG. 6, the sequence started in step 80 determines in step 81 whether there is a power failure. In the event of a power failure in step 81, the Vdc constant voltage control is started in step 82, and the sequence ends in step 85. On the other hand, if it is determined in step 81 that there is no power outage, Then, the presence or absence of the motor current is determined. If the motor current is present in step 83, the Vdc constant voltage control is started in step 82, and the sequence ends in step 85. On the other hand, if it is determined in step 83 that there is no motor current, the Vdc constant voltage control is stopped, and the sequence ends in step 85. The above sequence shall be started at fixed time intervals (for example, 0.1 second).

Next, the configuration and operation of the power failure detection circuit in the control circuit 21 will be described with reference to FIG. 7 (a).

In Fig. 7 (a), 150 is a three-phase diode bridge, 151 is a single-pass filter, 152 is a comparator, 153 is a reference voltage source for setting the power failure detection level, and others. Are the same as those in FIG. The voltage value of the AC power supply 1 is isolated and stepped down by the voltage detector 11 to generate the three-phase voltage signal Vsdet. In the diode bridge 150, Vsdet is subjected to full-wave or half-wave rectification and input to the low-pass filter 151. As a result, the DC voltage Vs_act is output to the output of the low-pass filter 15 1 when the AC power supply 1 is normal. On the other hand, when AC power supply 1 is out of power, the output value is zero. Therefore, by comparing the output value of the low-pass filter 15 1 with Vshut that satisfies Vshut <Vs_act, the output of the comparator 15 2 has a high level when the AC power supply is normal and the AC power supply Sometimes low levels are obtained. By connecting the output signal of the comparator 152 thus generated to the input terminal of the microcomputer, it becomes possible for the microcomputer to recognize the occurrence of a power failure.

Next, the configuration and operation of the motor current detection circuit in the control circuit 21 will be described with reference to FIG. 7 (b).

In FIG. 7 (b), 160 is a three-phase diode bridge, and 161 is The low pass filter, 162 is the comparator, 163 is the reference voltage source for setting the motor current detection level, and the other numbers are the same as in Fig. 1. The current value of the motor 6 is converted into an insulation and voltage signal by the current detector 13 and input to the low-pass filter 16 1. As a result, a value of zero is output to the output of the mouth-to-pass filter 16 1 when the motor 6 is stopped, and a value of zero or more is output when the motor 6 is operating. Thus, by comparing the output value of the low-pass filter 16 1 with the Vac and ac> 0 Vac and ac at the comparator 162, the output of the comparator 162 has a high level when the motor is stopped. At the time of motor operation, one level is obtained. By connecting the output signal of the comparator 162 thus generated to the input terminal of the microcomputer, the microcomputer can recognize whether or not the motor current is present (that is, whether or not the motor is operating).

FIG. 7 (c) is a diagram showing another embodiment of the motor current detection circuit different from FIG. 7 (b). In Fig. 7 (c), 170 is a single-phase diode bridge, 171 is a low-pass filter, 172 is a comparator, 173 is a reference voltage source for setting the motor current detection level, Other numbers are the same as in Fig. 1. The input current value of inverter 3 is converted into an insulation and voltage signal by current detector 175 and input to low-pass filter 171. As a result, zero is output to the output of the low-pass filter 17 1 when the motor 6 is stopped, and a value equal to or greater than zero is output when the motor 6 is operating. Therefore, by comparing the output value of the single-pass filter 17 1 with the output value of Vac and dc> 0, Vac and dc in the comparator 17 2, the output of the comparator 17 2 has a high level when the motor is stopped. When the motor is running, one level is obtained. By connecting the output signal of the comparator 172 generated in this way to the input terminal of the microcomputer, the presence or absence of the motor current (that is, whether or not the motor is operating) is determined by the microcomputer. Can be recognized.

Next, the operation of the Vdc constant voltage control system will be described with reference to FIG.

In FIG. 8, Vdc_ref is the Vdc voltage command value, Gd is the ON signal of switching element S1, Gc is the ON signal of switching element S2, and 120, 122, and 124 are the upper and lower limit signals. Mitsuba, 121 and 123 are proportional-integral controllers, and 125 is PWM generation means. In FIG. 8, reference numeral 126 denotes a Vdc voltage control system, and reference numeral 127 denotes a DC reactor current control system to which a current command value from the voltage control system 126 is input.

The difference between the voltage command value Vdc ref and the actual output voltage Vdc is input to the limiter 120. By limiting the upper and lower limits here, the integral value of the proportional integral type controller 1221, which is provided in the subsequent stage, is prevented from being excessively increased. The proportional integral controller 122, which receives the output of the limiter 120 as an input, calculates a DC reactor current command value that is optimal for bringing Vdc closer to Vdcref. The limiter 1 2 2 which receives the output of the proportional integral controller 1 2 1 as an input has the function of giving the upper and lower limit to the current command value, and the upper limit is set to 8 The lower limit value means the charging current limit value of the secondary battery 8. These charge / discharge current limit values are updated at fixed time intervals (for example, at 0.1 second intervals) according to the remaining amount of the secondary battery 8. This makes it possible to suppress the discharge when the remaining amount of the secondary battery is small, and to suppress the charging when the remaining amount of the secondary battery is excessive. The output value of the limiter 122 is taken as the new current command value IL ref, which is the difference from the actual DC reactor current value IL. The proportional-integral controller 123 using the obtained difference as an input calculates an optimal duty ratio command value for bringing IL close to IL ref. The limiter 124, which receives the output of the proportional integral controller 123, sets the maximum value of the triangular wave signal Sig2 in the PWM generation means described later to the upper limit. You. The minimum value of the triangular wave signal Sigl is set as the lower limit value. By performing this limit processing, the duty ratio of the switching signal generated based on the output signal comp of the limiter 124 is prevented from becoming zero or one.

Next, the configuration and operation of the PWM generating means 125 to which the output signal comp of the limiter 124 is input will be described with reference to FIG. In the circuit diagram of the PWM generator shown in FIG. 9 (b), 130 is a triangular wave generator, and 131 and 132 are comparators. To the negative input terminal of the comparator 131, the signal S igl obtained by adding the amplitude Vamp generated by the triangular wave generator 130, the triangular wave of the period T sw and V ofst is input, and to the positive input terminal of Inputs the signal comp described above. As a result, a high level is output to the output terminal Gd of the comparator 13 only when comp> Sigl. The above-mentioned signal comp is inputted to the minus input terminal of the other comparator 132, and the triangular wave signal Sig2 generated by the triangular wave generator 130 is inputted to the plus input terminal of the same comparator. As a result, a high level is output to the output terminal G c of the comparator 132 only when comp and Sig2. In the circuit of FIG. 9 (b) described above, Vofst satisfying the relationship of equation (6) is input, and when G d and G c are at the high level, the switching elements SI and S 2 are turned on. By setting the logic of the gate drive circuit 9 to be turned on, it is possible to alternately turn on and off the switching elements S1 and S2 at the switching frequency Tsw with the dead time Td interposed therebetween.

T swV ofs t

T d =… (6)

2 V amp

FIG. 9 (a) shows the waveform of each part in the aforementioned PWM generation means and the state of the switching elements SI and S2. As described above, the first embodiment described with reference to FIG. 1 is a case where the AC power supply 1 or the secondary battery 8 is used as a normal power supply, and the secondary battery 8 is used at the time of a power failure. . On the other hand, the second embodiment shown in FIG. 10 is a case where the AC power supply 1 and the diode bridge 2 in FIG. 1 are replaced with a primary battery 140.

In the embodiment shown in FIG. 10, the voltage command value Vdcreff of Vdc is set to a value higher than the output voltage of the primary battery 140. As a result, under the condition that the remaining amount of the secondary battery 8 is equal to or higher than the overdischarge level and equal to or lower than the overcharge level, the power of the secondary battery 8 is preferentially used. Conversely, when the remaining amount of the secondary battery 8 is insufficient, the electric power of the primary battery is supplied to the motor load 6. As a result, regenerative power can be charged and reused while using a primary battery that does not have a charging function as a power source, and an energy-saving effect can be produced. FIG. 11 shows a third embodiment in which the present invention is applied to an elevator system.

In Fig. 11 1, 15 1 is a motor shaft, 1 50 is a drive pulley, 1 5 2 is a pulley, 1 5 3 is a counterweight, 1 5 4 is a riding basket, 1 5 5 is a rope, 1 5 6 Is the car call button, 157 is the control circuit of the elevator system, 158 is the signal button of the car button, 159 is the signal circuit from the control circuit of the elevator system, and 1 6 Reference numeral 0 denotes a signal line from the control circuit 157 of the elevator system to inverter 3. In the elevator system shown in Fig. 11, when the car call button 1556 is pressed, the car is driven from the control circuit 1557 of the elevator system to Inver evening 3 and the car is moved. The driving pattern of the electric motor 6 for moving to the calling floor is sent out by the signal line 160. In addition, after passengers have been loaded on the calling floor, the car will travel from the control circuit 157 of the Elevate overnight system to Inver Evening 3 to move the car to the destination floor. The driving pattern of the electric motor 6 is transmitted by the signal line 160. For this reason, the control device 1 5 7 of the elevator system

1. Whether the basket call button or the destination button has been pressed.

2. Whether you arrived at the destination floor.

This state signal is held internally, and this state signal is input to the control circuit 21 via the signal line 159, and the control circuit 21 executes the flowchart shown in FIG. 12 described later. This makes it possible to stop the switching of SI and S2 when the motor is stopped without detecting the current of the motor 6. Thus, in applications where the timing information of the start and stop of the electric motor 6 can be easily obtained as in the case of the elevator, it can be implemented with a simpler configuration than the first embodiment shown in FIG.

Next, the flowchart of FIG. 12 will be described.

In FIG. 12, the sequence started in step 90 determines in step 91 whether or not there is a power failure. If a power failure occurs in step 91, the Vdc constant voltage control is started in step 94, and the sequence ends in step 96. On the other hand, if it is determined in step 91 that there is no power outage, it is determined in step 92 whether the car call button or the destination button has been pressed. If it is not determined in step 92 that the car call button or the destination button has been pressed, the Vdc constant voltage control is stopped in step 95, and the sequence ends in step 96. On the other hand, if it is determined in step 92 that the call button or the destination button has been pressed, it is determined in step 93 whether the vehicle has arrived at the destination floor. If it is determined in step 93 that the vehicle has arrived at the destination floor, the process proceeds to step 95, in which the Vdc constant voltage control is stopped, and the sequence ends in step 96. On the other hand, if it is not determined in step 93 that the vehicle has arrived at the destination floor, After starting Vdc constant voltage control in step 94, the sequence ends in step 96. It is assumed that the sequence of FIG. 12 described above is started at regular time intervals (for example, 0.1 second).

FIG. 13 is a diagram showing another operation example of the boosting switching element S1 and the step-down switching element shown in FIG.

In the previous embodiment, as shown in FIG. 9, the step-up switching element S 1 and the step-down switching element were alternately turned on and off. However, as shown in Fig. 13 (a) and (b), it is not always necessary to turn on and off alternately. It is only necessary that the on-time of both the boost switching element S 1 and the step-down switching element be provided during the power row operation and the regenerative operation. By performing such a switching operation, charge / discharge control can be performed without determining whether the power operation is being performed or the regenerative operation is being performed.

Claims

The scope of the claims

1. A diode bridge connected to an AC power supply to convert AC to DC, an inverter connected to the DC side of the diode bridge via a smoothing capacitor to convert DC to AC, and an inverter connected to the diode bridge. A motor connected in parallel to the smoothing capacitor via a motor connected to the AC side in the evening and a bidirectional buck-boost circuit having a first switching element and a second switching element. A secondary battery, and control means for turning on the first switching element and the second switching element at least once during each operation of the motor for power and regeneration. Discharge control device.

2. A diode bridge that is connected to an AC power supply and converts AC to DC; an inverter connected to the DC side of the diode bridge via a smoothing capacitor to convert DC to AC; A secondary battery connected in parallel to the smoothing capacitor via a motor connected to the AC side and a bidirectional buck-boost circuit having a first switching element and a second switching element And a control unit for alternately turning on and off the first switching element and the second switching element.

3. A diode bridge that is connected to an AC power supply and converts AC to DC, an inverter that is connected to the DC side of the diode bridge via a smoothing capacitor and converts DC to AC, An electric motor connected to the AC side of the night, a boost switching element connected in parallel with the smoothing capacitor via a step-down switching element, and a parallel connection with the step-up switching element via a reactor A connected secondary battery, and control means for turning on the step-down switching element and the step-up switching element at least once during each of the operation of the electric motor during power operation and regeneration. And a charge / discharge control device.

4. A diode bridge connected to an AC power supply to convert AC to DC, and an inverter connected to the DC side of the diode bridge via a smoothing capacitor to convert DC to AC. A motor connected to the AC side of the inverter, a boosting switching element connected in parallel with the smoothing capacitor via a step-down switching element, and a parallel connection with the voltage-up switching element via a reactor A charging / discharging control device comprising: a secondary battery connected to the power supply; and control means for alternately turning on and off the step-down switching element and the step-up switching element.

5. A diode bridge for converting an AC power supply into a DC output voltage, a smoothing capacitor connected to the DC output side of the diode bridge, and converting the DC voltage of the smoothing capacitor into a variable frequency and a variable voltage. An inverter driven by the inverter, a motor driven by the inverter, a secondary battery connected to the smoothing capacitor via a bidirectional buck-boost circuit, and a first switch of the buck-boost circuit. A charge / discharge control device comprising control means for alternately turning on / off a switching element and a second switching element with a dead time therebetween.

6. In Claim 5,

A charge / discharge control device comprising means for controlling a voltage of the smoothing capacitor to a constant value higher than a voltage value rectified by the diode bridge.

7. In Claim 6,

A charge / discharge control device comprising: a detection unit that detects a power failure of the AC power supply; and a unit that starts gate switching of the step-up / down circuit in response to the detection unit.

8. In Claim 6,

A charge / discharge control device comprising: a detection unit for detecting a drive current of the electric motor; and a unit for starting gate switching of the step-up / step-down circuit in response to the detection unit.

9. A diode bridge connected to an AC power supply for converting AC to DC, a smoothing capacitor, and an inverter connected to the DC side of the diode bridge via the smoothing capacitor for converting DC to AC. The inverter was connected in parallel to the smoothing capacitor via a motor connected to the AC side of the inverter and a bidirectional step-up / step-down circuit having a first switching element and a second switching element. A secondary battery, an elevator car that moves up and down by the electric motor, a car call button of the elevator motor, and the first switching element and the second Control means for turning on the switching element at least once, and when a car call is generated by the car call button, the first switch by the control means is provided. A charge / discharge control device characterized by starting to turn on and off a switching element and the second switching element.

10.A diode bridge connected to an AC power supply for converting AC to DC, a smoothing capacitor, and an inverter connected to the DC side of the diode bridge via this smoothing capacitor for converting DC to AC. The inverter is connected in parallel to the smoothing capacitor via a motor connected to the evening AC side and a bidirectional buck-boost circuit having a first switching element and a second switching element. The first switching element and the second switching element described above are reduced during the operation of each of the rechargeable battery, the elevator moving up and down by the motor, and the powering and regeneration of the motor. Control means to turn on once, and when the car arrives at the destination floor, A charge / discharge control device, wherein the on / off of the first switching element and the second switching element by the control means is terminated.

1 1. In Claims 3 and 4,

Means for detecting a remaining amount of the secondary battery, and means for changing a limit value of a current command value of a current control system relating to the reactor according to the detected value. Control device.

1 2. In claims 1 to 11,

A charge / discharge control device having a configuration in which the diode bridge is replaced with a primary battery.