JP2010035372A - Emergency power supply circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an emergency power supply circuit that attains device size reduction and easily outputs a variable DC voltage and a variable AC voltage, without having to add transformer and a commutator. <P>SOLUTION: Energy accumulated in a storage battery 7 is supplied to a DC/DC converter 6; the DC/DC converter 6 ensures a DC voltage between DC busbars by a step-up action so as to input the energy to a full-bridge inverter 4 as a DC voltage; the full-bridge inverter 4 converts the DC voltage into an AC voltage so as to output the AC voltage to the AC output side. When a DC voltage, in place of the output of the AC voltage, is outputted to the DC output side, a DC voltage stepped down by utilizing an upper arm (a semiconductor element T<SB>3</SB>, in an illustrated example) of the full-bridge inverter 4 and a reactor L1 is outputted to the DC output side via a contact point of a switching relay 3 switched from the AC output side to the DC output side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an emergency power supply circuit for reducing the size of an apparatus using an AC and DC output converter in common in an emergency power supply such as an elevator that switches between an AC power supply and a DC power supply.

  Conventionally, an emergency power supply for an elevator is connected to an AC uninterruptible power supply that backs up the control equipment of the elevator in order to convert the direct current to alternating current during a power failure so that the elevator can be continuously operated. It is known (see Patent Document 1).

  Conventionally, in an emergency emergency power supply, a DC / DC converter is connected to the battery in order to be able to supply DC power as well as AC power so that the brake can be controlled manually in an emergency. A power supply is ensured (see Patent Document 2).

Thus, in an emergency power supply for a conventional elevator, an AC output is required to back up an elevator control device and a DC voltage is required to manually control a brake in an emergency. In the case of obtaining DC voltage in an emergency, the conventional method is to convert the output to a backup power supply capable of AC output with a transformer and rectify the output to obtain DC voltage, or after directly rectifying the AC output, In many cases, a method of converting to a DC voltage using a DC / DC converter or a method of securing a DC voltage by changing an AC output voltage and adjusting a voltage after rectification is employed.
JP 07-232872 A JP 2002-171783 A

  In the case of obtaining a DC voltage, the conventional method requires components such as a rectifier and a transformer, and the apparatus becomes large or expensive. In the case of a transformer, when it is desired to change the voltage, the transformer must be redesigned and cannot be easily changed.

  Moreover, it is necessary to be able to output an AC voltage and a DC voltage to the control device as an emergency backup power source for the elevator control device. However, it is not always necessary to simultaneously output the AC voltage backing up the control device and the DC voltage for releasing the manual brake.

  Accordingly, an object of the present invention is to provide an emergency power supply circuit that can easily output variable DC voltage and AC voltage without adding a transformer and a rectifier as described above, and can reduce the size of the apparatus. There is to do.

  In order to solve the above problems, the present invention provides a first power converter that converts DC power from a storage battery into DC power of a desired voltage, and second power connected to the first power converter via a smoothing capacitor. An emergency power supply circuit composed of a converter is connected to a power supply line of an AC power supply and a load, and normally supplies power from the AC power supply to the load and charges the storage battery via the second power converter. In the emergency power supply circuit, the second power converter includes a full-bridge circuit composed of four semiconductor elements and at least one reactor, and a switching relay for switching the output of the second power converter to AC or DC When a circuit is provided and the second power converter outputs an alternating current, four semiconductor elements are controlled to output an alternating voltage, and when the second power converter outputs a direct current And outputs a DC voltage to control the semiconductor elements of the upper arm of at least one phase, characterized in that.

  An emergency power circuit comprising a first power converter that converts DC power from the storage battery into DC power having a desired voltage, and a second power converter connected to the first power converter via a smoothing capacitor. Is connected to a power supply line of an alternating current power source and a load, and supplies power to the load from the alternating current power source and charges the storage battery via the second power converter at all times. The two power converter includes a half bridge circuit composed of two semiconductor elements and one reactor, and includes a switching relay circuit that switches the output of the second power converter to alternating current or direct current, and the second power converter Controls the two semiconductor elements to output an alternating voltage, and when the second power converter outputs a direct current, controls the upper arm semiconductor element to control the direct current. And outputs the pressure.

  According to the present invention, when outputting AC or DC, the second power converter (inverter and reactor) can be used in common, and AC output and DC output are not required at the same time. For example, control for an elevator It is possible to reduce the size of the entire apparatus in a backup power supply in case of an emergency of the device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an emergency power supply circuit according to an embodiment of the present invention. In FIG. 1, 1 is an AC input power source, 2 is a relay (input relay) that disconnects the AC input power source 1 when the input power source is abnormal, and 3 is a switching relay that switches the output to an AC (AC) side or a DC (DC) side. 4 has a series circuit of the upper semiconductor element T ₁ and the lower series circuit and the semiconductor element T ₂ of the upper semiconductor element T ₃ and the lower side of the semiconductor element T ₄ constituting the upper and lower arms, and these two Full-bridge inverter (second power converter) in which two series circuits are connected in parallel, 5 is a smoothing capacitor disposed between DC buses, 6 is a bidirectional DC / DC converter (first power converter), Reference numeral 7 denotes a storage battery, and an emergency power supply circuit is constituted by these components. Connection point of the series circuit of the semiconductor element T ₁ and the semiconductor element T ₂ of the full bridge inverter 4 is connected to the return line of the AC input power supply 1, a connection point of the series circuit of the semiconductor device T ₃ and the semiconductor element T ₄ reactor L1 The other end of the reactor L <b> 1 is connected to the movable contact of the switching relay 3. One switching contact of the switching relay 3 is connected to the positive electrode of the AC input power supply 1, the other switching contact of the switching relay 3 is connected to the positive electrode of the DC output, and the negative electrode of the smoothing capacitor 5 is connected to the negative electrode of the DC output. Yes. The AC output is connected to an AC load such as a main motor for lifting and lowering the elevator, and the DC output is connected to a DC load such as a manual brake. FIG. 1 shows an emergency power supply circuit according to an embodiment of the present invention applied to a commercial power supply type uninterruptible power supply.

Next, the operation of the emergency power supply circuit according to the embodiment of the present invention shown in FIG. 1 will be described. When the AC input is normal, energy is output from the AC input power source 1 to the AC (AC) output side via the contact of the input relay 2 that is ON (closed), and at the same time, the semiconductor element of the full bridge inverter 4 The smoothing capacitor 5 disposed between the DC buses is charged via the diodes D _{1 to} D ₄ connected in reverse parallel to the T _{1 to} T ₄ , and the storage battery 7 is charged via the bidirectional DC / DC converter 6. . Bidirectional DC / DC converter 6 is composed of two semiconductor elements T _5, T ₆ and a reactor L2, the smoothing capacitor 5 is turned on by forced control circuit shown semiconductor elements T ₅ of the bidirectional DC / DC converter 6 converted and stored charging DC voltage by the reactor L2 to the energy and then charge the battery 7 by releasing energy stored in the reactor L2 is turned off by the semiconductor element T ₅ the unshown control circuit to the battery 7 To do. The capacitor 8 is a capacitor prepared for ripple absorption.

When the AC input becomes abnormal, the input relay 2 is turned off (opened), thereby interrupting the supply of energy from the AC input power source 1 to the smoothing capacitor 5, so that the potential of the smoothing capacitor 5 disposed between the DC buses is When the voltage drops and drops to a predetermined constant potential, the energy stored in the storage battery 7 is supplied to the bidirectional DC / DC converter 6, and the bidirectional DC / DC converter 6 boosts this energy between the DC buses by boosting action. The full-bridge inverter 4 converts the direct-current voltage into an alternating-current voltage and outputs the alternating-current (AC) output side. Also when outputting the DC voltage to current (DC) output instead of the output of the AC voltage, the nodes on one arm (series circuit of the semiconductor device T ₃ and the semiconductor element T ₄ in the illustrated example of the full bridge inverter 4 And the DC voltage stepped down by using the reactor L1 is output to the direct current (DC) output side through the contact of the switching relay 3 switched from the alternating current output side to the direct current output side. In this case, the full bridge inverter 4 functions as a step-down chopper circuit. A control circuit for operating the step-down chopper circuit is not shown.

The timing for switching the switching relay 3 is a high-frequency switching pattern of a semiconductor element in which a control circuit (not shown) generates an AC voltage of the full-bridge inverter 4 when a DC voltage is required (for example, when a manual brake is released). Once stopped, the switching relay 3 is switched by outputting a relay switching signal from a control circuit (not shown). Thereafter, a control circuit (not shown) performs switching for the step-down chopper operation on the semiconductor element that generates the DC voltage. When outputting a direct current (DC) voltage, the upper semiconductor element (in the illustrated example, the semiconductor element T ₃ ) is controlled to be turned on / off, and the on-duty ratio at this time is adjusted to output the direct current voltage. Can be set to an arbitrary DC voltage equal to or lower than the DC voltage between the DC buses.

FIG. 2 is a diagram showing a specific example in the case of increasing the capacity of the DC output in the emergency power supply circuit according to the embodiment of the present invention. FIG. 2 illustrates only the configuration of the improved full-bridge inverter 4, and the remaining configuration is the same as the description of FIG. In Figure 2, connect another reactor L3 to the other arm of the full bridge inverter 4 (in the illustrated example has a node in the series circuit of the semiconductor element T ₁ and the semiconductor element T _2), changeover relay correspondingly 3 is increased. In this configuration, when increasing the capacity of the output DC voltage, the same signal is supplied to the upper semiconductor elements (in the illustrated example, the semiconductor elements T ₁ and T ₃ ) connected to the respective arms. By controlling the input to the semiconductor element and adjusting the on-duty ratio at this time, it is possible to set the output DC voltage to an arbitrary DC voltage equal to or lower than the DC voltage between the DC buses. By connecting the reactor L3 in this way and inputting and controlling the same signal to each arm, the DC voltage capacity can be doubled.

FIG. 3 is a diagram illustrating a specific example of a case where a half-bridge inverter configuration is used instead of the full-bridge inverter configuration in the emergency power supply circuit according to the embodiment of the present invention. 3, in order to obtain the configuration of the half-bridge inverter 4 ′, a capacitor 51 and a capacitor 52 are provided instead of the smoothing capacitor 5 provided in the configuration of the full-bridge inverter 4 of FIG. 1, and the capacitor 51 and the capacitor 52 are connected in series. The return line on the alternating current (AC) output side is obtained from the middle point of both capacitors connected in series. The parallel connection of the series circuit of the series circuit and the capacitor 51 and the capacitor 52 of the semiconductor element T ₃ and the semiconductor element T _4. Thus since the semiconductor element T ₁ and the semiconductor element T ₂ is not required, it is possible to provide an inexpensive emergency power supply circuit since the reduce the expensive parts.

  In FIGS. 1 to 3 described above, when a direct current (DC) voltage is output, control not shown as a configuration for reducing the switching loss of the semiconductor element in which the reactor is connected to the arm of the bridge inverter. By setting the DC bus voltage from the storage battery 7 to the smoothing capacitor 5 to a voltage slightly higher than the DC output voltage required at the output stage of the DC output by the boosting action of the bidirectional DC / DC converter 6 by the circuit, the step-down chopper The loss generated in the entire apparatus can be reduced by lowering the voltage applied to the arm of the bridge inverter (or half bridge inverter) to be operated and reducing the number of times of switching.

It is a block diagram which shows the structure of the emergency power supply circuit which concerns on embodiment of this invention. It is a figure which shows the specific example in the case of increasing the capacity | capacitance of DC output in the emergency power supply circuit which concerns on embodiment of this invention. It is a figure which shows the specific example at the time of setting it as a half bridge inverter structure instead of a full bridge inverter structure in the emergency power supply circuit which concerns on embodiment of this invention.

Explanation of symbols

1 AC input power 2 Input relay 3 Switching relay 4 Full bridge inverter (second power converter)
4 'half-bridge inverter (second power converter)
5 Smoothing capacitor 6 Bidirectional DC / DC converter (first power converter)
7 Storage battery 8 Ripple absorption capacitor
51, 52 Capacitor T _{1 to} T ₆ Semiconductor element D _{1 to} D ₆ Diode L _{1 to} L ₃ Reactor (AC / DC)

Claims (3)

An emergency power circuit comprising a first power converter that converts DC power from a storage battery into DC power of a desired voltage, and a second power converter connected to the first power converter via a smoothing capacitor, In an emergency power supply circuit that is connected to a power supply line of an AC power supply and a load, and normally supplies power from the AC power supply to the load and charges the storage battery via the second power converter,
The second power converter includes a full bridge circuit composed of four semiconductor elements and at least one reactor,
A switching relay circuit for switching the output of the second power converter to AC or DC;
When the second power converter outputs alternating current, the semiconductor device is controlled to output an alternating voltage,
When the second power converter outputs a direct current, the emergency power supply circuit outputs a direct current voltage by controlling the semiconductor element of the upper arm for at least one phase. An emergency power circuit comprising a first power converter that converts DC power from a storage battery into DC power of a desired voltage, and a second power converter connected to the first power converter via a smoothing capacitor, In an emergency power supply circuit that is connected to a power supply line of an AC power supply and a load, and normally supplies power from the AC power supply to the load and charges the storage battery via the second power converter,
The second power converter includes a half bridge circuit composed of two semiconductor elements and a reactor.
A switching relay circuit for switching the output of the second power converter to AC or DC;
When the second power converter outputs alternating current, the two semiconductor elements are controlled to output alternating voltage,
When the second power converter outputs a direct current, the emergency power supply circuit outputs a direct current voltage by controlling a semiconductor element of the upper arm.   3. The emergency power supply circuit according to claim 1 or 2, wherein when direct current is output, the first power converter is controlled to lower the direct current voltage, and the semiconductor element of the second power converter is switched. An emergency power supply circuit characterized by reducing the number of times to reduce switching loss.

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