JP2010273506A - Dc power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC power supply device having a good power factor, and ensuring high calmness and quietness. <P>SOLUTION: The DC power supply device includes a reactor 2 connected to one end of an AC power supply 1, a rectifying means 3 connected to the other end of the AC power supply 1 and the other end of the reactor 2, a short circuit means 4 connected to the same other end of the AC power supply 1 and the same other end of the reactor 2, and short-circuiting the AC power supply 1 via the reactor 2, and a control means 5 which controls the short circuit means 4. The control means 5 controls the short circuit means 4, and short-circuits the AC power supply 1 only for a period calculated based on a natural frequency of the reactor 2 once per half cycle of the AC power supply 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a DC power supply device used for a refrigerator, an air conditioner, a heat pump type hot water heater, and the like.

  In a DC power supply device that rectifies an AC voltage of an AC power supply and converts it into a DC voltage, it is known as an effective means to extract more effective power from the AC power supply. Moreover, the improvement of the power factor is also known as a means for complying with harmonic current regulations such as the International Electrotechnical Commission (IEC).

  The means to improve the power factor is to turn on the switch that shorts the AC power supply after the AC voltage of the AC power supply has passed through the zero point, thereby shorting the AC power supply through the reactor for an appropriate short time. It is shown that an alternating current is passed even during a period when the power is not supplied until the power factor is improved. (For example, see Patent Document 1)

Japanese Patent No. 2763479 (page 9-10, FIG. 1)

  The conventional DC power supply device shown in Patent Document 1 improves the power factor by short-circuiting the AC power supply through the reactor and extending the energization period of the AC current, but short-circuiting the AC power supply through the reactor. As a result, an alternating current flows through the reactor, a magnetic flux is generated in the windings in the reactor, and an attractive force is generated. Therefore, there is a problem that the reactor itself causes a forced vibration and generates unpleasant noise.

  Examples of means for suppressing reactor noise include those that suppress vibration by increasing the rigidity of the reactor, and those that do not leak noise to the outside by providing soundproofing means. There's a problem.

  The present invention has been made to solve the above-described problems, and provides a DC power supply apparatus that can economically suppress reactor noise while improving the power factor of the power supply.

  A DC power supply device according to the present invention includes a reactor connected to one end of an AC power supply, a rectifier connected to the other end of the AC power supply and the reactor, rectifying an AC voltage into a DC voltage, and the reactor via the reactor. A short-circuit means for short-circuiting the AC power supply, and a control means for controlling the short-circuit means. The control means controls the short-circuit means so that the characteristic of the reactor is once in a half cycle of the AC power supply. The AC power supply is short-circuited only during a period calculated based on the frequency.

The DC power supply device of the present invention obtains the effect of suppressing the noise of the reactor while improving the power factor by determining the time for short-circuiting the AC power supply based on the natural frequency of the reactor.

2 is an electric circuit diagram of the DC power supply device according to Embodiment 1. FIG. FIG. 6 is a diagram showing operation waveforms according to the first embodiment. 2 is a plan view of a reactor according to Embodiment 1. FIG. 2 is a cross-sectional view of a reactor according to Embodiment 1. FIG. 2 is a magnetic circuit diagram of the reactor according to Embodiment 1. FIG. It is a figure which shows the vibration waveform of a reactor. It is a figure which shows the vibration waveform of the reactor which concerns on Embodiment 1. FIG. FIG. 3 is a diagram illustrating a drive signal of a control unit according to the first embodiment.

Embodiment 1 FIG.
FIG. 1 is an electric circuit diagram of a DC power supply device according to Embodiment 1 of the present invention.
In FIG. 1, a DC power supply device 7 includes a reactor 2 connected to one end of a commercial AC power supply 1, a rectifier 3 connected to the other end of the AC power supply 1 and the other end of the reactor 2, and an AC power supply 1. A short-circuit means 4 connected to the other end and the other end of the reactor 2 and a control means 5 for detecting the zero point of the AC power source 1 and controlling the short-circuit means 4 are provided. The rectifier 3 includes a full-wave rectifier circuit 31 including diodes 31a to 31d, and a capacitor 32 that is connected to the output terminal of the full-wave rectifier circuit 31 and smoothes the output voltage. The short-circuit means 4 includes a full-wave rectifier circuit 41 composed of diodes 41 a to 41 d and an IGBT (Insulated Gate Bipolar Transistor) 42 that short-circuits the AC power supply 1 based on the control means 5. The load 6 of the external device is connected to the output terminal of the full wave rectifier circuit 31.

Next, the operation principle of the DC power supply device 7 according to the first embodiment will be described. FIG. 2 shows a time axis on the horizontal axis, an output diagram of an AC voltage and two AC currents in the upper stage, and a timing diagram for turning on / off the IGBT 42 in the lower stage.
In FIG. 2, an alternating voltage 11 indicates an alternating voltage supplied from the alternating current power source 1, and an alternating current 12 indicates a charging current when the IGBT 42 is always off. The alternating current 12 is a current that flows when the capacitor tries to charge from the difference between the voltage of the alternating current power source 1 and the voltage of the capacitor 32, and the energization period is short and uneven. The drive signal 14 indicates the timing at which the control unit 5 turns on the IGBT 42 immediately after the zero point detection, turns it off after a short time, or controls the IGBT 42. The alternating current 13 is an alternating current that flows when the IGBT 42 is turned on / off based on the drive signal 14. When the IGBT 42 is turned on, the AC current 13 is short-circuited and the current starts to flow suddenly from the AC power supply 1. When the IGBT 42 is turned off, the short-circuit is opened and the amount of current is once reduced. It shows that the charging current flows on the same principle.
The DC power supply device 7 according to the first embodiment is configured to short-circuit the AC power supply 1 by turning on / off the IGBT 42 by the control means 5 for a short period of time immediately after the AC voltage becomes zero as described above. The energization period of the alternating current can be extended and the power source power factor can be improved.

Next, the structure of the reactor 2 will be described. FIG. 3A is a plan view of the reactor 2 according to Embodiment 1 of the present invention, and FIG. 3B is a cross-sectional view taken along a cutting line AA in FIG.
3 (a) and 3 (b), the reactor 2 includes an E iron core 22 having a square column at the center and a column slightly higher than the square column at both ends, and a winding 21 wound around the square column of the E core. , And an I iron core 23 welded so as to be supported by the pillars at both ends of the E iron core 22. There is a gap 24 at the abutting portion of the square pillar of the E iron core 22 and the I iron core 23. In the reactor 2, an alternating current flows through the winding 21 wound around the E iron core 22, thereby generating a magnetomotive force and forming a magnetic circuit in which the air gap 24 becomes a magnetic resistance.

FIG. 4 is an equivalent circuit diagram in which the reactor 2 is regarded as a magnetic circuit.
In FIG. 4, U is a magnetomotive force, R is a magnetic resistance, and Φ is an alternating magnetic flux. When the alternating current flowing through the winding 21 is I and the number of windings is N, the following equations (1) and (2) are established.
Magnetomotive force U = N · I (1)
Alternating magnetic flux Φ = U / R (2)
The attractive force F is proportional to the square of the alternating magnetic flux Φ (F∝Φ ² ).
In other words, the alternating current I causes an attractive force to be generated in the E iron core 22 and the I iron core 23 in the vicinity of the air gap 24, thereby generating forced vibration. Moreover, since the alternating current I changes abruptly immediately after the IGBT 42 is turned on / off, a strong force acts on the E iron core 22 and the I iron core 23 in the vicinity of the air gap 24, and free vibration inherent to the solid is generated. This free vibration is a cause of noise, and by reducing this free vibration, the noise of the reactor 2 can be suppressed.

FIG. 5 is a diagram showing a vibration waveform of the reactor 2 before the present invention is applied.
In FIG. 5, the drive signal 14 is a timing diagram in which the horizontal axis is the time axis and the IGBT 42 is turned on / off. The short circuit time Tb is the short circuit time when the power source power factor of the DC power supply device 7 is maximized. Show. The free vibration 15 a indicates vibration generated by an alternating current that suddenly flows into the reactor 2 when the alternating current power supply 1 is short-circuited when the IGBT 42 is turned on. The free vibration 15b indicates vibration that occurs when the short circuit is finished and the alternating current flowing through the reactor 2 is rapidly reduced when the IGBT 42 is turned off. The free vibration 15 is a vibration that is actually generated in the reactor 2 by combining the free vibration 15a and the free vibration 15b, and indicates the possibility that the free vibration 15a and the automatic vibration 15b increase.

FIG. 6 is a diagram showing a vibration waveform of the reactor 2 according to the first embodiment of the present invention.
In FIG. 6, the drive signal 16 is a timing diagram in which the horizontal axis is the time axis and the IGBT 42 is on / off controlled. The short circuit time T indicates the time during which the AC power supply 1 is short-circuited, and the short period ΔT is A short period after the short circuit time Tb elapses to maximize the power factor, and the period T0 and the frequency ω indicate the period and frequency of the natural vibration generated in the E iron core 22 and the I iron core 23, respectively. The other symbols are the same as those in FIG. The free vibration 15a is a vibration that occurs when the current flowing through the reactor 2 increases rapidly, and sin (ωt): t can be expressed as time. Moreover, since the free vibration 15b is a vibration that occurs when the current flowing through the reactor 2 is drastically reduced, it becomes sin (ωt−π). That is, the automatic vibration 15b has a half-cycle phase difference from the automatic vibration 15a. When the short-circuit time T is an integral multiple of T0 and T = n · T0: n = 1, 2, 3,..., The automatic vibration 15 cancels the automatic vibration 15a and the automatic vibration 15b, and the vibration is reduced. The By extending the short period ΔT to the short circuit time Tb that maximizes the power factor, and controlling as the short circuit time T = Tb + ΔT, the electric power factor of the DC power supply device 7 is brought close to the maximum, and noise generated from the reactor 2 Can be reduced.

FIG. 7 is a diagram illustrating a drive signal of the control unit according to the first embodiment of the present invention.
In FIG. 7, drive signals 17 to 21 are timing diagrams for taking the time axis on the horizontal axis and controlling the IGBT 42 on / off. Other symbols are the same as those in FIG. The drive signal 17 indicates a control timing in which the time for turning on the IGBT 42 is matched with the short circuit time Tb, the time for turning it off is slightly advanced, and the short circuit time is adjusted to an integral multiple of the natural period T0. The drive signal 18 indicates a control timing in which the time for turning off the IGBT 42 is matched with the short circuit time Tb, the time for turning on is slightly delayed, and the short circuit time is adjusted to an integral multiple of the natural period T0. The drive signal 19 indicates a control timing in which the time for turning off the IGBT 42 is combined with the short circuit time Tb, the time for turning on is slightly advanced, and the short circuit time is adjusted to an integral multiple of the natural period T0. The drive signal 20 and the drive signal 21 indicate control timings in which the time for turning on and off the IGBT 42 is adjusted for a short period to adjust the short-circuit time to an integral multiple of the natural period T0. Any control method of the drive signals 17 to 21 can obtain the same effect as when the drive signals 16 are controlled. Of course, quietness is given priority over the electric power factor, and the short circuit time can be made longer or shorter than the short circuit time Tb while making the short circuit time an integral multiple of the natural period T0.

  As described above, the first embodiment of the present invention can drive the IGBT 42 based on the natural frequency of the reactor 2 and suppress the vibration of the reactor 2. As a result, the noise of the reactor 2 can be suppressed while improving the power factor. The effect of improving quietness and quietness can be obtained without attaching a large soundproofing device or silencer.

  DESCRIPTION OF SYMBOLS 1 AC power supply, 2 Reactor, 3 Rectification means, 31 Full wave rectification circuit, 31a-31d Diode, 32 Capacitor, 4 Short circuit means, 41 Full wave rectification circuit, 41a-41d Diode, 42 IGBT, 5 Control means, 6 Load, 7 DC power supply, 11 AC voltage, 12, 13 AC current, 14, 16, 17, 18, 19, 20, 21 Drive signal, 15, 15a, 15b Free vibration, 21 windings, 22 E iron core, 23 I iron core 24 gap, 25 bottom plate, F attractive force, I alternating current, R magnetoresistance, U magnetomotive force, Φ alternating magnetic flux, Tb, T short circuit time, ΔT short period, T0 natural period, ω natural frequency.

Claims (2)

A reactor connected to one end of an AC power supply; a rectifying means connected to the other end of the AC power supply and the reactor; and rectifying an AC voltage into a DC voltage; and a shorting means short-circuiting the AC power supply through the reactor And a control means for controlling the short-circuit means,
The control means controls the short-circuit means to short-circuit the AC power supply for a period calculated based on the natural frequency of the reactor once every half cycle of the AC power supply. Power supply.   The control means controls the short-circuit means to start short-circuiting the AC power supply in the vicinity of the zero point of the AC voltage, and finish the short-circuit after a time that is an integral multiple of the natural period of the reactor. The DC power supply device according to claim 1.

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