JP2011199977A - Dc power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress reactor noise which is produced in synchronization with the short-circuit operation of a reactor, in a load near a boundary where the reactor short-circuit operation for adjustment of a DC power voltage begins to start.SOLUTION: In the DC power unit, a control unit 9 varies an ON period Δt (0≤t), with reference to a difference between the target DC voltage for controlling a DC voltage into a desired value and the output of a DC voltage detector, however, it is possible to avoid the alternate occurrence of a power cycle, when a current generated by short-circuiting the switching part flows to a reactor and a power cycle when it does not flow even in an input current, in the vicinity of the boundary between 0 and a value that begins to be larger than 0 with respect to the ON period Δt, by changing the variation of the ON period Δt between the time, when it decreases and the time when it increases.

Description

  The present invention relates to a DC power supply device that controls a power supply circuit, and more particularly to a DC power supply device that uses a DC voltage variable function of a power factor correction circuit.

  The DC power supply device includes a rectifying / smoothing unit that rectifies and smoothes an AC voltage from an AC power source into a DC voltage, a reactor connected between the AC power source and one AC input terminal of the rectifying / smoothing unit, and the AC Switching means for short-circuiting a power supply via the reactor, zero-cross detection means for detecting a zero-cross point of the AC power supply, DC voltage detection means for detecting and outputting an output DC voltage value of the rectifying and smoothing means, and the DC voltage Referring to the output of the detection means, the control means is configured to continuously short-circuit the switching means only during the ON period Δt (0 ≦ t) after the zero-cross point delay period Δd (0 ≦ d). The control means changes the delay period Δd (0 ≦ d) and the ON period Δt (0 ≦ t), thereby controlling the output DC voltage value.

  Conventionally, in order to control the DC voltage to a desired value, the control means refers to the difference between the target DC voltage and the output of the DC voltage detecting means and varies the ON period Δt (0 ≦ t). Is done. (For example, refer to Patent Document 1).

  FIG. 3 shows a conventional DC power supply device described in Patent Document 1. In FIG. As shown in FIG. 3, the DC power supply device converts the AC voltage from the AC power supply 1 into a DC voltage by the rectifying and smoothing unit 2, and the ripple component of the DC voltage is eliminated by the smoothing capacitor. The smoothed DC voltage is input to the inverter unit 3, and the electric motor 4 is driven. Further, a reactor 5 is connected between the AC power source 1 and one AC input terminal, and a short-circuit portion 6 that short-circuits the AC power source 1 through the reactor 5 and a zero cross point of the AC power source 1 are detected. A zero-cross detecting unit 7 for detecting, a DC voltage detecting unit 8 for detecting and outputting an output DC voltage value of the rectifying and smoothing unit, and a delay period Δd (0 ≦ d) of the zero-crossing point with reference to the output of the DC voltage detecting unit A control unit 9 that continuously short-circuits the switching unit only during the ON period Δt (0 ≦ t) is connected. The controller 9 refers to the difference between the target DC voltage and the output of the DC voltage detecting means to vary the ON period Δt (0 ≦ t) in order to control the DC voltage to a desired value. FIG. 4 shows the relationship between the current input from the AC power supply to the DC power supply and the ON period Δt. When the target DC voltage is 255 V at AC 200 V, the ON period Δt becomes greater than 0 at 3.0 A or more. As the current increases, the ON period Δt increases and the DC power supply voltage is maintained at a constant value.

JP 2004-72806 A

  However, in the conventional configuration, in the input current near the boundary where the ON period Δt is greater than 0 and 0, depending on the load of the DC power supply, the power supply cycle in which the current short-circuiting the switching unit flows to the reactor and the power supply that does not flow Periods may occur alternately. Since the noise level generated from the reactor is different between the power cycle in which the short-circuit current flows in the reactor and the power cycle in which the short-circuit current does not flow, there is a problem that abnormal noise is generated from the reactor due to the difference in the noise level in each power cycle.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a DC power supply device that controls a DC voltage to a predetermined value without generating abnormal noise from a reactor.

  In order to solve the conventional problems, a DC power supply apparatus according to the present invention includes a rectifying / smoothing means for rectifying and smoothing an AC voltage from an AC power supply into a DC voltage, and an AC input of one of the AC power supply and the rectifying / smoothing means. A reactor connected between the terminals, a switching means for short-circuiting the AC power supply via the reactor, a zero-cross detection means for detecting a zero-cross point of the AC power supply, and an output DC voltage value of the rectifying and smoothing means DC voltage detecting means for detecting and outputting, and referring to the output of the DC voltage detecting means, continuously after the delay period Δd (0 ≦ d) of the zero crossing point and during the on period Δt (0 ≦ t). The control means controls the ON period Δt so that the output of the DC voltage detection means becomes the target DC voltage, and the change in Δt is achieved. It is intended to change when you decrease the time to increase.

  As a result, even in the case of an input current near the boundary where the ON period Δt is greater than 0, it is possible to avoid alternately generating a power cycle in which the current short-circuiting the switching unit flows and a power cycle in which the current does not flow. It becomes possible.

  In the DC power supply device of the present invention, since the power cycle in which the current short-circuited in the switching section does not flow alternately and the power cycle in which the current does not flow does not occur alternately, no abnormal noise is generated from the reactor, and the noise of the DC power supply device can be reduced It becomes.

1 is a block diagram of a DC power supply device according to a first embodiment of the present invention. FIG. 4 is a relationship diagram between the current input to the DC power supply device and the on period Δt in Embodiment 1 of the present invention Block diagram of a conventional DC power supply device described in Patent Document 1 Relationship diagram between current input to conventional DC power supply and on-period Δt in Patent Document 1

  The first invention comprises a rectifying / smoothing means for rectifying and smoothing an AC voltage from an AC power supply into a DC voltage, a reactor connected between the AC power supply and one AC input terminal of the rectifying / smoothing means, Switching means for short-circuiting an AC power supply via the reactor, zero-cross detection means for detecting a zero-cross point of the AC power supply, DC voltage detection means for detecting and outputting an output DC voltage value of the rectifying and smoothing means, and the DC DC having a control means for continuously short-circuiting the switching means only during the ON period Δt (0 ≦ t) after the delay period Δt (0 ≦ d) of the zero cross point with reference to the output of the voltage detection means In the power supply apparatus, the control means controls the ON period Δt so that the output of the DC voltage detection means becomes a target DC voltage, and decreases when the amount of change of the ON period Δt is increased. Therefore, even in the case of the input current near the boundary where the ON period Δt is greater than 0, the power cycle in which the current short-circuiting the switching unit flows to the reactor and the power cycle in which the current does not flow alternately occur. By avoiding this, the power cycle in which the current short-circuited in the switching unit does not flow alternately and the power cycle in which the current does not flow are not alternately generated, so that no abnormal noise is generated from the reactor and the noise of the DC power supply device can be reduced.

  In the second invention, in particular, in the DC power supply device of the first invention, when the switching means is short-circuited a plurality of times during the half cycle of the power supply, the amount of change in the ON period Δt is changed every time the switching means is turned on. By doing so, it is possible to reduce the noise of the DC power supply device that performs switching a plurality of times.

  The third invention is the DC power supply device of the first and second inventions, in particular, when the switching means is short-circuited a plurality of times during a half cycle of the power supply, and the amount of change in the on period Δt for each period when the switching means is turned on By changing the above, it is possible to control with high accuracy and to supply a stable DC voltage.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a block diagram according to the first embodiment of the present invention. The DC power supply device converts an AC voltage from the AC power supply 1 into a DC voltage by the rectifying and smoothing unit 2, and a ripple component of the DC voltage is deleted by the smoothing capacitor. The smoothed DC voltage is input to the inverter unit 3, and the electric motor 4 is driven. Further, a reactor 5 is connected between the AC power source 1 and one AC input terminal, and a short-circuit portion 6 that short-circuits the AC power source 1 through the reactor 5 and a zero cross point of the AC power source 1 are detected. A zero-cross detecting unit 7 for detecting, a DC voltage detecting unit 8 for detecting and outputting an output DC voltage value of the rectifying and smoothing unit, and a delay period Δd (0 ≦ d) of the zero-crossing point with reference to the output of the DC voltage detecting unit ) After that, the control unit 9 for continuously short-circuiting the switching unit only during the ON period Δt (0 ≦ t) is connected. The control unit 9 refers to the difference between the target DC voltage and the output of the DC voltage detecting means to control the DC voltage to a desired value and varies the ON period Δt (0 ≦ t). The decrease is set smaller than when the amount of change in Δt is increased.

  The operation and action of the DC power supply device configured as described above will be described below.

  FIG. 2 shows the relationship between the current input from the AC power source to the DC power supply device and the first ON period Δt. When the target DC voltage is 255 V at AC 200 V, the AC 3. At 0A, the DC voltage matches the target DC voltage. Once the current input to the DC power supply exceeds AC 3.0A and the ON period becomes smaller than AC 3.0A after Δt becomes larger than 0, the DC voltage becomes larger than the target DC voltage. By setting the decreasing amount of Δt to be half of the increasing amount, a state where the ON period Δt is greater than 0 continues for at least one power cycle. Therefore, by setting the decreasing amount to be smaller, it is possible to continue the state where the ON period Δt is greater than zero.

  As a result, when the input current is stable in the vicinity of AC 3.0 A, it is possible to avoid alternately generating a power cycle in which the current short-circuiting the switching unit flows to a reactor and a power cycle in which the current does not flow. Since the power supply cycle in which the current that short-circuits the switching unit does not flow in the reactor and the power cycle in which the current does not flow are not alternately generated, no abnormal noise is generated from the reactor, and noise in the DC power supply device can be reduced.

  Similarly, in the case of a current that is switched multiple times, when the switching means is turned on twice from the case of turning on the switching means twice, the amount of change in the on period Δt is turned on once. By reducing the turn-on time twice, it is possible to avoid the occurrence of alternating power-on cycles that turn on once and power-on cycles that turn on twice, and reduce the generation of abnormal noise from the reactor. The noise of the DC power supply can be reduced.

  Furthermore, by setting the amount of change of Δt for each ON period, it is possible to eliminate generation of abnormal noise from the reactor and supply a stable DC voltage.

  As described above, the direct-current power supply device according to the present invention can supply direct-current voltage while suppressing reactor noise, so that it operates at night such as an air conditioner or a heat pump type hot water heater and requires quietness. Applicable to household electrical appliances.

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Rectification smoothing part 3 Inverter part 4 Electric motor 5 Reactor 6 Short circuit part 7 Zero cross detection part 8 DC voltage detection part 9 Control part

Claims (3)

Rectifying and smoothing means for rectifying and smoothing an AC voltage from an AC power supply into a DC voltage, a reactor connected between the AC power supply and one AC input terminal of the rectifying and smoothing means, and the AC power supply for the reactor Switching means that is short-circuited through, a zero-cross detection means that detects a zero-cross point of the AC power supply, a DC voltage detection means that detects and outputs an output DC voltage value of the rectifying and smoothing means, and an output of the DC voltage detection means And a control means for continuously short-circuiting the switching means for an ON period Δt (0 ≦ t) after a delay period Δd (0 ≦ d) of the zero-crossing point. The means controls the ON period Δt so that the output of the DC voltage detection means becomes the target DC voltage, and changes depending on whether the amount of change in the ON period Δt is decreased or increased. DC power supply device according to claim and. 2. The DC power supply device according to claim 1, wherein, when the switching unit is short-circuited a plurality of times during a power supply half cycle, the amount of change in the ON period Δt is changed every time the switching unit is turned on. 3. The DC power supply according to claim 1, wherein when the switching means is short-circuited a plurality of times during a power supply half cycle, the amount of change in the ON period Δt is changed for each period during which the switching means is turned on. apparatus.

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