JP4841303B2 - DC power supply - Google Patents

Description

  The present invention relates to a direct current power supply device capable of improving an appropriate power factor.

  A rectification type switch element that constitutes a short circuit is provided in the direct current portion of the direct current power supply device that rectifies the alternating current once in a half cycle of the alternating current voltage. There has been proposed a high power factor power supply device that improves the power factor by flowing a current flowing through a reactor provided between the two to the DC output side when the switch element is turned off (see Patent Document 1).

In this DC power supply device, the power factor can be kept high in advance for the ON start timing (hereinafter referred to as ON timing) and ON duration (hereinafter referred to as ON time) of the switch element, which are important parameters in improving the power factor. Based on this setting, the switch element is turned on and off.
Japanese Patent Laid-Open No. 7-7946

  However, the ON timing and the ON time at which a high power factor can be maintained vary depending on the load amount of the load connected to the DC power supply device, a change in power supply voltage, and the like. For this reason, when the ON timing and ON time determined experimentally under specific conditions are used, the optimum power may not be obtained depending on the load amount of the load connected to the DC power supply device and the fluctuation of the power supply voltage. The rate is not improved.

  For example, regarding the ON timing of the switch element, since the current is often delayed from the phase of the AC voltage, considering the case where the current remains at the voltage zero cross point, the ON timing of the switch element is the zero cross point of the AC voltage. Generally, it is slightly delayed (provided with a delay time). However, depending on the situation, this delay time may be insufficient, and when the switch element is turned on, a current with a delayed phase may still flow.

  Such a situation will be specifically described based on the waveform diagram of FIG. In FIG. 8, the waveform is shown in two parts, upper and lower, with the upper part being one cycle of AC voltage, the lower part being one cycle of AC current generated from this AC voltage, and the ON of the switch element that performs short circuit control. Or indicates OFF. In both the upper and lower waveform diagrams, the vertical axis represents voltage value [V] (current value is [A]), and the horizontal axis represents time [ms]. Further, ON and OFF of the switch element are expressed in a so-called active high state in which the rising edge of the rectangular wave indicates ON.

  In the waveform diagram shown in FIG. 8, the ON timing of the switch element is determined with reference to a point of approximately 0 V (zero cross) at which the half cycle of the AC voltage ends and changes from “+” to “−”. The switch element is turned on at point a) shown in FIG.

  If there is no delay in the current phase, as shown in the current waveform X in the figure, the point where the voltage zero crossing and the current zero are almost the same or the current zero is zero, then the voltage zero crossing, and the load is turned on by turning on and off the switch element The operation of flowing current into the side is performed satisfactorily.

  However, as shown by the current waveform Y in the figure, if the current phase is delayed and the current continues to flow even when the switch element is turned on, the current flows up to the point b as a result of turning on the switch element. It will be slower than the rate of decline. As a result, the phase of the current is further delayed with respect to the phase of the AC voltage. If the switching element is repeatedly turned on before the current becomes zero in this way, the current phase with respect to the AC voltage phase gradually shifts in the direction of delay, and not only the power factor cannot be improved, but also the DC There is a possibility that control of the power supply itself may be disabled.

  The present invention has been made to solve the above problems, and a first object of the present invention is to detect a delay in the current phase with respect to the power supply voltage and turn on the short-circuit means after the point where the current becomes zero. Thus, it is an object to provide a DC power supply device that can avoid the uncontrollable state due to the deterioration of the delay of the current phase with respect to the power supply voltage and can reliably improve the power factor.

  Further, the second object of the present invention is to delay the current phase by extending the short-circuit period according to the delay when the short-circuiting operation of the short-circuit means is delayed from the voltage zero cross when the current phase is delayed. It is an object to provide a direct current power supply device that can be controlled so as to be eliminated, avoid an uncontrollable state, and reliably improve the power factor.

  A first feature according to an embodiment of the present invention is that in a DC power supply device, a rectifying unit connected to an AC power source and rectifying AC to DC, a reactor inserted between the rectifying unit and the AC power source, Provided between the reactor and the rectifying means, short-circuit means for short-circuiting the input, zero-cross detection means for detecting zero-cross timing when the input voltage from the AC power supply becomes zero, and detecting zero of the voltage on the output side of the reactor Control for short-circuiting the short-circuiting means after the zero-crossing timing detected by the zero-crossing detecting means after the zero-crossing timing detected by the zero-crossing detecting means and after the zero-crossing timing detected by the zero-crossing detecting means Means.

  A second feature according to the embodiment of the present invention is that in a DC power supply apparatus, a rectifying means connected to an AC power supply and rectifying AC to DC, a reactor inserted between the rectifying means and the AC power supply, Provided on the load side of the reactor, short-circuit means for short-circuiting the input, zero-cross detection means for detecting zero-cross timing when the input voltage from the AC power supply becomes zero, and current detection means for detecting zero current from the AC power supply And short-circuit control means for short-circuiting the short-circuit means after the zero-cross timing detected by the zero-cross detection means and after the time when the current detection means detects zero current. The short-circuit operation period of the short-circuit means is changed according to the time from the zero-cross timing by the zero-cross detection means until the current detection means detects zero current. And a short circuit time control unit for.

  According to the first aspect of the present invention, the delay of the current phase with respect to the power supply voltage is detected, and the short-circuit means is turned on after the point where the current becomes zero. It is possible to provide a DC power supply device that can avoid the state and reliably improve the power factor.

  According to the invention of claim 4, when a delay occurs in the current phase and the short-circuiting operation of the short-circuit means is delayed from the voltage zero cross, the short-circuit period is extended in accordance with the delay to delay the current phase. It is possible to provide a DC power supply device that can be controlled so as to be eliminated, avoid an uncontrollable state, and reliably improve the power factor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
As shown in FIG. 1, the DC power supply device 1 according to the first embodiment of the present invention has an AC voltage source 2 on the input side and a load 3 such as a motor drive inverter device on the output side. It is connected.

  The DC power supply device 1 includes a rectifying means 11 connected to an AC voltage source 2 and rectifying AC to DC, a reactor 12 inserted between the rectifying means 11 and the AC voltage source 2, and the reactor 12 and the AC voltage source. 2, a zero cross detecting means 13 for detecting a point where the value of the input voltage from the AC voltage source 2 becomes zero, one end between the reactor 12 and the rectifying means 11, and the other end of the reactor 12. Is provided between the AC voltage source 2 and the rectifying means 11 that are not connected to each other, and the voltage detecting means 14 for detecting that the voltage generated in this portion has become zero, the voltage detecting means 14 and the rectifying means 11 And a control means 16 for controlling the short-circuit means 15. Further, a smoothing capacitor 17 is connected in parallel between the rectifier 11 and the load 3 in the DC power supply device 1 shown in FIG.

  Each of the zero-cross detection means 13 and the voltage detection means 14 is composed of a circuit using a rectification type photocoupler, and the photocoupler is turned on while the positive or negative voltage applied to the photocoupler exists, and the voltage is almost equal. When it reaches near zero, the photocoupler is turned off. Therefore, in the zero cross detection means 13, the time when the photocoupler is turned off becomes the zero cross point. Similarly, the voltage detection means 14 detects zero voltage by turning off the photocoupler when the voltage between both ends becomes almost zero. It should be noted that since both the zero-cross detection means 13 and the voltage detection means 14 have an operation threshold of the photocoupler itself, complete zero cannot be detected, but it is possible to detect a value that can be regarded as substantially zero in terms of control. is there.

  Here, the role of the voltage detection means 14 will be described. As described in Background Art and Problems, when the load is light, the current becomes zero before the power supply voltage becomes zero. However, when the load is heavy, the current phase is delayed with respect to the power supply voltage. If the short-circuit means 15 is turned on while such a current continues to flow, the current phase will be further delayed. For this reason, it is desirable to turn on the short-circuit means 15 after the current becomes zero. However, it is necessary to detect this current as alternating current and near zero, and an existing current detector such as a current transformer detects an integrated current value in a short time. It was difficult to detect. A current detector that detects an instantaneous current value is expensive. Therefore, it is the voltage detection means 14 that plays a role of detecting that the voltage value is zero more accurately and inexpensively.

  Note that the phase delay of the current refers to a current in which the phase of the period until the current becomes zero with respect to the zero crossing of the voltage of the AC voltage source 2 is delayed. This phase delay occurs for each positive and negative AC voltage. Incidentally, the reactor 12 is an inductive load, and the current phase does not advance. However, when the load is light, the current becomes zero before the zero cross of the voltage of the AC voltage source 2.

  The zero cross detection means 13 is a value of 0 V (zero cross) that appears when the input voltage supplied from the AC voltage source 2 to the DC power supply device 1 changes from “+” to “−” or “−” to “+”. The voltage detection means 14 detects the value of 0 V (zero cross) of the voltage on the output side of the reactor 12. When the voltage on the output side of the reactor 12 becomes 0V, the input current from the AC voltage source 2 coincides with zero. That is, the current flows from the AC voltage source 2 until the voltage detection means 14 detects zero voltage. Therefore, the presence of the phase delay current can be detected by judging from the time relationship between the voltage zero detection and the voltage zero crossing in this portion. For this reason, a current whose phase is delayed flows until the voltage detection unit 14 detects zero voltage after the zero cross detection unit 13 detects the zero cross.

  The outputs of the zero cross detection means 13 and the voltage detection means 14 are input to the control means 16.

  The control means 16 rectifies the period during which the voltage detection means 14 detects the voltage after the zero cross detection means 13 detects that the input voltage is zero based on the detection results of the zero cross detection means 13 and the voltage detection means 14. The short-circuit means 15 composed of a switch-type switch element is continuously turned OFF, and after the voltage detection means 14 detects zero voltage, the short-circuit means 15 is controlled to be ON for a predetermined time.

  Further, when the voltage detection means 14 detects zero voltage before the zero cross detection means 13 detects the zero cross, the control means 16 turns on the short circuit means 15 for a predetermined time based on the zero cross detection of the zero cross detection means 13. Control is performed. This short-circuit operation is executed every half cycle of the AC power supply cycle.

  As shown in FIG. 2, various signals from the zero cross detection means 13, the voltage detection means 14, and the load 3 are input to the control means 16, and short circuit control means 16a and short circuit prohibiting means 16b are provided therein. . A load status signal from the load 3 is input to the short-circuit control unit 16a that receives the zero-cross signal from the zero-cross detection unit 13 and generates a signal for controlling the ON / OFF of the short-circuit unit 15.

  In the short-circuit control means 16a, data of ON timing and ON time of the short-circuit means 15 corresponding to the load status of the load 3 connected in advance is set. The ON timing data is the time (delay time) from when the zero cross detection means 13 detects the AC power supply zero cross until the short circuit means 15 is turned ON. The ON time data is the time when the short circuit means 15 is turned ON. It is the ON continuation time from OFF to OFF.

  The data set in the short-circuit control means 16a is based on tests under standard conditions. Generally, when the load is heavy, it is desired to supply current to the load side at an early stage of the AC voltage phase. The timing is short, that is, a short delay time is set, and the ON time is set long to increase the current. On the other hand, when the load is light, the ON timing is set long and the ON time is set short.

  In order to improve power factor and reduce power supply harmonics, the short-circuit means 15 may be turned on and off a plurality of times, such as about 3 to 5 times, during the AC half wave of the power supply voltage. In this case, the ON timing and the ON time are set for each short-circuit operation, but the tendency of setting the ON timing and the ON time for the load described above is the same.

  The zero-cross signal from the zero-cross detection means 13 and the zero-voltage detection signal from the voltage detection means 14 are input to the short-circuit prohibition means 16b. The short-circuit prohibiting means 16b sends the short-circuit prohibiting signal to the short-circuit control means 16a until a zero-voltage signal is input after receiving the zero-cross signal from the zero-cross detecting means 13, that is, during a period in which a phase delayed current continues to flow. Supply.

  Therefore, the short-circuit control means 16a does not turn on the short-circuit means 15 during a period in which the short-circuit prohibition signal is received from the short-circuit prohibition means 16b even when the preset ON timing is reached.

  On the other hand, when there is no delay in the current phase, the detection signal of the voltage detection means 14 is zero at the same time or before the zero cross signal from the zero cross detection means 13 is received. In this case, the short circuit prohibiting means 16b No short-circuit prohibition signal is output. For this reason, the short-circuit means 15 is ON / OFF-controlled based on the ON timing and ON time data set in advance in the short-circuit prohibition means 16b when the short-circuit control means 16a receives the zero-cross signal from the zero-cross detection means 13. .

  FIG. 3 shows ON / OFF of each point of the zero cross detection means 13, the connection point voltage, the voltage detection means 14, and the short-circuit means 15 when the AC voltage source 2 (power supply voltage) changes from “−” to “+”. Or it is a time chart which shows "+" and "-". Further, when the AC voltage source 2 (power supply voltage) changes from “+” to “−”, only the power supply voltage and the connection point voltage “+” and “−” are reversed, and the zero cross detection means 13 and the voltage are changed. Since the output of the detection means 14 is the same, it is omitted.

  The solid line in FIG. 3 shows the operation when the power supply voltage and the current phase are substantially coincident, and the broken line shows the operation when the current phase with respect to the power supply voltage is delayed. The photocoupler constituting the voltage detection means 14 is turned off when the detection-side voltage falls within a predetermined threshold (for example, positive mass 2 V), and its inverted output (ON) becomes the output of the voltage detection means 14. The circuit is designed.

  First, when the power supply voltage and the current phase coincide with each other as indicated by a solid line, the zero cross detection means 13 is turned from OFF to ON immediately before the power supply voltage changes from “−” to “+”. That is, while the power supply voltage is changing from “−” to “+”, it changes to “−2 V”, “0 V (zero cross)”, and “2 V”. Therefore, the zero cross detection means 13 is turned on when the power supply voltage becomes “−2 V” and turned off when it exceeds “2 V”, and can detect the zero cross of the AC power supply voltage.

  In the DC power supply device 1, the voltage detection means 14 for detecting the delay of the current phase with respect to the power supply voltage is connected immediately after the reactor 12, and the voltage at this connection point is the “connection point voltage” in FIG. 3. In this example, since there is no delay in the current phase with respect to the power supply voltage, at the same time as the power supply voltage passes through the zero cross, the connection point voltage also passes through the zero cross and shifts from “−” to “+”. The photocoupler of the voltage detecting means 14 is turned ON by the movement of the connection point voltage from “−” to “+”, and the short circuit prohibiting means 16b is detected by detecting the voltage zero by the voltage detecting means 14 and detecting the zero cross of the AC power supply voltage. The short-circuit prohibiting signal is not output, and the short-circuit control means 16a is short-circuited to the short-circuit means 15 with a delay of Ton time (time until the short-circuit means 15 is turned on from the zero cross point of the power supply voltage) which is a preset ON timing. An ON signal for controlling is transmitted.

  When the short-circuit means 15 is turned on and short-circuit control is performed, the connection point voltage that has moved from “−” to “+” following the power supply voltage drops to 0 V, and after that, the period during which the short-circuit means 15 is ON is 0 V. To maintain.

  When the current phase is delayed as shown by the broken line in FIG. 3, the voltage detection means 14 outputs an ON output when the current approaches zero because the current phase is delayed. For this reason, the short-circuit prohibiting means 16b supplies a short-circuit prohibiting signal to the short-circuit control means 16a until the voltage detecting means 14 is turned ON, and the short-circuit control means 16a is short-circuit means even after the Ton time which is a preset ON timing. 15 is not turned ON. Thereafter, when the voltage detection means 14 is turned on and the short-circuit prohibition signal disappears, the short-circuit means 15 is turned on. The short-circuit control means 16a continues to turn on the short-circuit means 15 for a predetermined ON time, and the ON time has elapsed. At that time, the short-circuit means 15 is turned off. Since the short circuit time (ON time) is a predetermined value, the OFF of the short circuit means 15 is delayed by the amount of delay of the current phase.

  In this way, the delay of the current phase with respect to the power supply voltage is detected by using a photocoupler, and the short-circuit means is turned on after the point where the current becomes zero with respect to the zero cross point of the current as a reference. It is possible to provide a DC power supply device that can avoid an uncontrollable state due to a delay in the current phase and can reliably improve the power factor. Further, the detection of the phase delay of the current can be easily and reliably performed by using the terminal voltage on the reactor output side. In the first embodiment, since the short circuit time is kept constant regardless of the ON timing, a predetermined ON time can be reliably ensured even when the current phase is delayed.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In each embodiment described below, the same components as those described in the first embodiment are denoted by the same reference numerals, and the description of the same components is omitted because it is duplicated. To do.

  In the second embodiment, as shown in FIG. 4, a short circuit time control means 16c is newly added to the first embodiment, and a short circuit time (ON time) is added to the short circuit control means 16a. Instead, the difference is that the OFF timing (Toff time) for switching the short-circuit means 15 from ON to OFF starting from the zero cross point of the power supply voltage is stored, and the other configurations are the same.

  In the second embodiment, the zero-cross signal of the zero-cross detector 13, the zero-voltage detection signal of the voltage detector 14, and the OFF timing data of the short-circuit controller 16a are input to the short-circuit time controller 16c. The short-circuiting time control means 16c includes timing means, calculation means, and comparison means (not shown) inside, and measures the time T1 from when the zero cross signal is input by the timing means until the zero voltage detection signal is input. Then, the difference ΔT between the T1 time and the Ton time is obtained by the calculation means, and a signal for delaying the OFF timing by ΔT is output to the short-circuit control means 16a. That is, the OFF timing is changed from Toff to Toff + ΔT.

  Thus, by detecting the delay of the current phase with respect to the power supply voltage and turning on the short-circuit means after the point where the current becomes zero, it is possible to avoid the uncontrollable state due to the deterioration of the delay of the current phase with respect to the power supply voltage. In addition, it is possible to provide a DC power supply device that can improve the power factor, and shorten the ON time of the short-circuit means caused by the current phase delay, that is, shorten the time from when the short-circuit means is turned ON to when it is turned OFF. Therefore, it is possible to provide a DC power supply device that compensates for this and can reliably ensure the ON time of the short-circuit means.

(Third embodiment)
Next, a third embodiment of the present invention will be described.

  Unlike the first and second embodiments, the third embodiment is characterized in that the control means 16 is constituted by a microcomputer. Therefore, the control of the short-circuit operation of the short-circuit means 15 is processed by a program stored in the microcomputer, the ON timing is not determined, and after the zero-cross detection means 13 detects the zero-cross of the power supply voltage, the voltage detection Control is performed so that the short-circuit operation is started when the means 14 detects zero voltage, that is, this time is the ON timing. Further, the period during which the short-circuit means is turned on, that is, the ON time Tco is stored in advance corresponding to the load state, but when the current phase delay is larger than the predetermined value, the ON time is changed to be longer. Thus, a current phase lag compensation function for eliminating the current phase lag early is provided.

  Furthermore, in this embodiment, instead of the voltage detection means 14 shown in FIG. 1, an instantaneous value current detection means 18 is provided in series between the AC voltage source 2 and the rectification means 11 as shown in FIG. The instantaneous value current detection means 18 is expensive depending on the detection accuracy, but can detect the instantaneous value of the flowing current. Therefore, the instantaneous current detection means 18 can detect zero current.

  A current value that is not an instantaneous value used in other controls can be obtained by averaging the output of the instantaneous value current detection means 18 over a predetermined period of time.

  As shown in FIG. 6, the microcomputer includes a judgment / comparison unit 21, a storage unit 22, a timer 23, and a short-circuit control unit 24. The judgment / comparison means 21 reads, for example, the reference ON time Tco from the data stored in advance in the storage means 22 based on the signal input from the load, and short-circuits based on the time measured by the timer 23. A signal for performing control is generated and transmitted to the short-circuit control means 24. The short-circuit control means 24 causes the short-circuit means 15 to short-circuit based on this signal.

  Therefore, the procedure of short-circuit control for the short-circuit means 15 will be described using the flowchart of FIG.

  The determination / comparison unit 21 first determines the state of the load 3 connected to the DC power supply 1 based on the signal input from the load 3 (ST1), and stores it in the storage unit 22 in advance according to the state of the load. The stored ON time (Tco) is read (ST2).

  Subsequently, it is determined whether or not the zero cross of the power supply voltage input from the AC voltage source 2 to the DC power supply 1 is detected by the zero cross detection means 13 (ST3). Step 3 is repeated until a zero crossing of the power supply voltage is detected. If a zero cross is detected (Y in ST3), the timer 23 is started to obtain a delay time T1 used for current phase delay compensation described later (ST4), and then the voltage zero is detected by the instantaneous value current detection means 18 (ST5).

  If zero current is detected (Y in ST4), the judgment / comparison means 21 compares whether or not the delay time T1 counted by the timer 23 at that time is smaller than a predetermined value a, Judgment is made (ST6). When there is no current phase delay, the delay time T1 is “0” because the current is zero at the same time as or before the zero cross of the power supply voltage detected by the zero cross detecting means 13. Therefore, if it is smaller than the predetermined value a (Y in ST6), the initial ON time Tco is set as the correction ON time Te (ST81). Subsequently, a control signal is sent from the judgment / comparison means 21 to the short-circuit control means 24 to turn on the short-circuit means 15 (ST7).

  On the other hand, when there is a current phase delay, the delay time is T1. The predetermined value a is used to determine the degree of current phase delay. If the delay time T1 is greater than a, the current phase delay is considered to be considerably large. Therefore, if the delay time T1 is not smaller (larger) than the predetermined value a set in advance (N in ST6), the corrected ON time Te is set to a predetermined ON time Tco to improve the phase delay. It is changed (longer) to a value obtained by adding only the value a (ST82). Then, the short-circuit means 15 is short-circuited (ST7). Therefore, when there is no current phase lag, the short-circuit means 15 is turned on almost simultaneously with the zero cross of the power supply voltage, and when there is a current phase lag, zero current is detected after the zero cross.

  When the short-circuit means 15 is turned on, the timer 23 starts counting the ON duration time T2 (ST9). Then, the short-circuiting operation of the short-circuit means 15 is continued until this ON duration time T2 reaches a preset correction ON time Te (ST10). Then, when the ON duration time T2 reaches the correction ON time Te, the short-circuit means 15 is turned OFF (ST11).

  Subsequently, after the short-circuit means 15 is turned off, the short-circuit means 15 is turned on and off three times at a predetermined time interval (ST12), and then the timers T1 and T2 are reset to clear the correction ON time Te (Te = 0). ) (ST13), and this procedure is repeated again, whereby this control is executed every half cycle of the AC power supply.

  Thus, when there is no current phase delay, the short-circuit means 15 performs a short-circuit operation for a preset ON time Tco, and when the current phase delay is greater than a, the short-circuit means is equal to Tco + α. 15 performs a short circuit operation. As a result, when the current phase delay is large, the input current to the DC power supply device is increased by increasing the correction ON time Te, the current phase delay advances to the voltage phase side, and the current phase delay is eliminated. Therefore, it is possible to provide a DC power supply device that can avoid an uncontrollable state due to a delay in the current phase with respect to the power supply voltage and can reliably improve the power factor.

  In the present embodiment, the ON time is set to be extended by the time α when the current phase delay is larger than a. However, the ON time extension time is proportional to the phase delay T1 in order to perform finer control. It may be set continuously.

  In the third embodiment, the instantaneous value current detection means 18 is used instead of the voltage detection means 14, but the current phase delay with respect to the power supply voltage can be detected by any means. For this reason, the instantaneous value current detection means 18 may be used in the first and second embodiments, or the voltage detection means 14 may be used in the third embodiment. In any case, with the current zero cross point as a reference, the short circuit is turned on after the point at which the current becomes zero, thereby avoiding an uncontrollable state due to a delay in the current phase with respect to the power supply voltage and ensuring power factor It is possible to provide a DC power supply device that can improve the above.

  Furthermore, in the first to third embodiments, the example in which the short-circuit means is provided between the reactor and the rectifier circuit is shown. However, the short-circuit means may be provided between the rectifier circuit and the load. What is necessary is just to provide in the load side rather than.

  As described above, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.

It is a block diagram which shows the DC power supply device in 1st Embodiment. It is a block diagram which shows the structure of the control means in 1st Embodiment. It is a time chart which shows the short circuit control in 1st Embodiment. It is a block diagram which shows the structure of the control means in 2nd Embodiment. It is a block diagram which shows the DC power supply device in 3rd Embodiment. It is a block diagram which shows the structure of the control means in 3rd Embodiment. It is a flowchart which shows the flow of the short circuit control in 3rd Embodiment. It is a wave form diagram which shows the waveform in which the conventional short circuit control was performed.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... DC power supply device, 11 ... Rectification means, 12 ... Reactor, 13 ... Zero cross detection means, 14 ... Current detection means, 15 ... Short-circuit means, 16 ... Control means

Claims (5)

A rectifying means connected to an AC power source and rectifying AC to DC;
A reactor inserted between the rectifying means and the AC power source;
Short-circuit means provided on the load side of the reactor and short-circuiting the input,
Zero-cross detection means for detecting zero-cross timing when the input voltage from the AC power supply becomes zero;
Voltage detecting means for detecting zero of the voltage on the output side of the reactor;
Control for short-circuiting the short-circuit means after the zero-cross timing detected by the zero-cross detection means and after the time when the voltage detection means detects zero after the signals from the zero-cross detection means and the voltage detection means are input. Means,
A DC power supply device characterized by comprising: The control means includes
Short-circuit control means for controlling the short-circuit start timing and short-circuit duration of the short-circuit means based on the zero-cross timing detected by the zero-cross detection means,
When the voltage detection means does not detect zero voltage before the zero cross detection means detects the zero cross timing, the short-circuit control means performs the short-circuit operation by the short-circuit control means until the voltage detection means detects zero voltage. A short-circuit prohibiting control means for prohibiting;
The direct current power supply device according to claim 1, wherein:   The voltage detection means is configured by a rectification type photocoupler having one end connected between the reactor and the rectification means and the other end connected to a power supply line opposite to the reactor connection side of the AC power supply. The DC power supply device according to claim 1 or 2. A rectifying means connected to an AC power source and rectifying AC to DC;
A reactor inserted between the rectifying means and the AC power source;
Short-circuit means provided on the load side of the reactor and short-circuiting the input,
Zero-cross detection means for detecting zero-cross timing when the input voltage from the AC power supply becomes zero;
Current detection means for detecting zero current from the AC power supply;
Signals from the zero-cross detection means and the current detection means are input, and the short-circuit means is short-circuited after the zero-cross timing detected by the zero-cross detection means and after the time when the current detection means detects zero current. Short-circuit control means;
A short-circuit time control means for changing a short-circuit operation period of the short-circuit means according to a time from a zero-cross timing by the zero-cross detection means until the current detection means detects zero current;
A DC power supply device characterized by comprising:   5. The DC power supply device according to claim 4, wherein the current detection means is voltage detection means for detecting zero of the voltage on the output side of the reactor.

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