JP2011155767A - Power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a power supply device which makes a reactor more compact while observing the regulations of power supply harmonics. <P>SOLUTION: The power supply device includes a power supply phase detection circuit 5 which detects the zero-cross point of voltage by detecting the voltage phase of an AC power supply 1, an input current detection unit 8 which detects the input current of a boosting circuit 3, and a control unit 10 which performs switching control every half period of the AC power supply 1 based on the zero-cross point of voltage and the input current, so that the first half zero input current period from the zero-cross point of voltage to the zero-cross point of input current where the input current begins to flow becomes equal to the second half zero input current period from the zero-cross point of input current where the input current flow terminates to the next zero-cross point of voltage in consideration of a predetermined switching operation period and a passive operation period after the predetermined switching operation period. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply circuit control technique for converting a commercial power supply into a power supply for home appliances, and more particularly to a power supply device having a boost chopper type power factor improvement and harmonic current suppression function.

  Conventionally, there is a power supply device having a boost chopper type power factor improvement and harmonic current suppression function. As an example of this type of power supply apparatus, there is Patent Document 1 below.

  In the power supply device disclosed in Patent Document 1, when the input power supply is converted into a DC voltage and the load voltage is obtained by the boost chopper circuit, the switching element of the boost circuit is switched and short-circuited via the reactor (boost choke coil). Apply current to improve the power factor. The control unit that controls the power supply unit generates a modeling waveform in which a predetermined harmonic component is reduced from the input current waveform as a current command value, and the zero crossing in the first half of the half cycle of the AC power supply voltage follows the modeling waveform. By switching on and off the switching element a predetermined number of times from the point, it is possible to clear the power supply harmonic regulation without increasing the reactor inductance even in a large current region.

JP 2007-129849 A

  In the power supply device disclosed in Patent Document 1, after switching a predetermined number of times, an input current flows due to the passive operation of the reactor. The timing of the zero cross point at which the input current begins to flow coincides with the timing of the zero cross point in the first half of the half cycle of the AC power supply voltage, but the timing of the zero cross point at which the input current after the passive operation ends depends on the reactor inductance, When the reactor inductance is small, the timing is away from the zero-cross point in the second half of the half cycle of the AC power supply voltage. When the load is small, the input current becomes small, so this tendency becomes more prominent, and there is a possibility that the power supply harmonic regulation cannot be cleared. Therefore, in order to clear the power harmonic regulation even in the light load region, it is necessary to increase the reactor inductance, and there is a problem that it is difficult to downsize the reactor.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a power supply apparatus that can further reduce the size of a reactor while clearing power supply harmonic regulations.

  In order to solve the above-described problems and achieve the object, the present invention provides a power factor by short-circuiting the AC power supply by a switching element via a reactor when converting the AC power supply into a DC voltage to obtain a load voltage. In a power supply device to be improved, a booster circuit including the switching element, a power supply phase detection circuit for detecting a voltage zero cross point of the AC power supply by detecting a voltage phase of the AC power supply, and detecting an input current of the booster circuit An input current detection unit that performs switching operation of the switching element during a predetermined switching operation period based on the voltage zero cross point and the input current, and the switching element that is output based on a switching pulse output from the control unit. A drive unit that drives, the control unit at two consecutive voltage zero crossing points In consideration of the predetermined switching operation period and the passive operation period after the predetermined switching operation period, the input current at which the input current starts to flow from the first voltage zero-cross point for each half cycle of the AC power supply The switching operation is started so that the first half zero input current period up to the zero cross point of the input current is equal to the second half zero input current period from the zero cross point of the input current at which the input current ends to the next voltage zero cross point. A switching start time is determined, the switching operation is started at the switching start time, and the switching operation is stopped after the predetermined switching operation period has elapsed.

  According to the present invention, there is an effect that the reactor can be further reduced in size while the power harmonic regulation is cleared.

FIG. 1 is a diagram of a configuration example of the power supply device according to the first embodiment. FIG. 2 is a diagram illustrating another configuration example of the power supply device according to the first embodiment. FIG. 3 is a diagram of a configuration example of the control unit of the power supply device according to the first embodiment. FIG. 4 is a diagram for explaining switching control of the power supply device according to the first embodiment. FIG. 5 is a diagram illustrating the harmonic current characteristics included in the input current. FIG. 6 is a diagram illustrating an example of a fifth-order harmonic evaluation index with respect to the ratio between the first half quiescent current period and the second half quiescent current period. FIG. 7 is a timing chart for explaining the operation of the power supply apparatus according to the first embodiment. FIG. 8 is a timing chart for explaining the operation of the power supply device according to the second embodiment. FIG. 9 is a timing chart for explaining the operation of the power supply device according to the third embodiment.

  Hereinafter, a power supply device according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram of a configuration example of the power supply device according to the first embodiment. As shown in FIG. 1, the power supply device according to the first embodiment includes an AC power supply 1, a reactor (a boost choke coil) 3 a connected in series to one terminal side of the AC power supply 1, a rectifier circuit 2, and a booster The circuit 3, the smoothing capacitor 11 that smoothes the output voltage boosted by the booster circuit 3, the load 4, the power supply phase detection circuit 5 that detects the voltage zero cross point of the AC power supply 1, and the input current of the booster circuit 3 A current sensor (for example, CT) 6 for detection, an input current detection unit 8 for detecting an input current of the booster circuit 3 based on a detection signal from the current sensor 6, and an input current and power supply phase detection circuit by the input current detection unit 8 5, the controller 10 outputs a switching pulse signal for driving the booster circuit 3 to the drive unit 7 based on the detection result of the voltage zero crossing point 5, and the boost signal is driven by the drive signal from the controller 10. And a driving unit 7 for driving the 3.

  The booster circuit 3 includes a diode 3b1 having an anode connected to the input side of the rectifier circuit 2 of the reactor 3a, a diode 3b2 having an anode connected to the other terminal side of the AC power supply 1, a cathode of the diode 3b1, and a diode 3b2. The switching element (for example, IGBT; insulated gate transistor) 3c which short-circuits the connection point with a cathode to the negative terminal side of the rectifier circuit 2 is provided. The booster circuit 3 improves the power factor by causing a short-circuit current to flow through the reactor 3a by the switching element 3c.

  Note that the power supply apparatus according to the first embodiment may be configured as shown in FIG. FIG. 2 is a diagram illustrating another configuration example of the power supply device according to the first embodiment. As shown in FIG. 2, in another configuration example of the power supply apparatus according to the first embodiment, the reactor 3a is connected in series to the positive terminal side of the rectifier circuit 2, and the booster circuit 3 includes the reactor 3a, the diode 3b, Are connected in series, and a switching element 3c for short-circuiting the connection point between the reactor 3a and the diode 3b to the negative terminal side of the rectifier circuit 2 is provided.

  Next, the configuration and schematic functions of the control unit 10 of the power supply device according to the first embodiment will be described. FIG. 3 is a diagram of a configuration example of the control unit of the power supply device according to the first embodiment.

  The control unit 10 calculates a switching operation period setting unit 110 in which a predetermined switching operation period Ton is set in advance and a time (hereinafter referred to as “switching start time”) td for starting the switching operation according to the magnitude of the input current. A switching start time calculation unit 111 that performs switching, a switching permission signal generation unit 112 that generates a switching permission signal that permits switching in the switching operation period Ton from the switching start time td, and switching that generates a switching pulse signal based on the switching permission signal And a pulse generation unit 114.

  The switching pulse generator 114 calculates a current command value of a modeling waveform for reducing a predetermined harmonic component from the waveform of the input current, and outputs the current command value as a PWM signal. The switching pulse generator 114 switches from the PWM signal. A current command value creating circuit 150 that creates a current command value having a permission signal width, a comparator 400 that compares the current command value with a voltage corresponding to the input current, a switching pulse based on a comparison result of the comparator 400 and a switching permission signal And a logic circuit 500 for generating a signal. In addition, about the calculation method of the current command value of a modeling waveform, it shall perform control similar to the power supply device which concerns on Unexamined-Japanese-Patent No. 2007-129849 of this applicant, and shall add it to a part of this invention.

  Next, switching control of the power supply device according to the first embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 is a diagram for explaining switching control of the power supply device according to the first embodiment.

  In the power supply device according to the first embodiment, the period from the first voltage zero cross point in the half cycle of the power supply voltage to the zero cross point of the input current at which the input current starts to flow (hereinafter referred to as “first half zero input current period Td”), switching The period from the zero-cross point of the input current at which the input current ceases to flow due to the passive operation of the reactor 3a after the operation to the next voltage zero-cross point in the half cycle described above (hereinafter referred to as “second half zero-input current period To”) is made equal. In addition, the switching start time td is controlled.

  4A and 4B show the power supply voltage waveform. The lower diagram of FIG. 4A is a diagram showing an input current waveform (hereinafter referred to as “waveform A”) when the switching operation is started from the voltage zero cross point, and the lower diagram of FIG. 4B is the first embodiment. It is a figure which shows the input electric current waveform (henceforth "the waveform B") at the time of applying the switching control of the power supply device concerning.

  As shown in FIG. 4A, in the waveform A, the input current waveform is entirely shifted forward, and the shape of the waveform does not exhibit a substantially sine wave shape. On the other hand, since the waveform B is controlled so that Td and To are substantially equal, the waveform has a substantially sinusoidal shape.

  FIG. 5 is a diagram illustrating the harmonic current characteristics included in the input current. The horizontal axis indicates the harmonic order, and the vertical axis indicates the harmonic current value. In each harmonic order, the left bar graph indicates the harmonic current in the case of the waveform A, and the right bar graph indicates the harmonic current in the case of the waveform B.

  As shown in FIG. 5, when comparing waveform A and waveform B, the value of the third harmonic current is larger in waveform B, but the value of the fifth harmonic current is larger in waveform B. Is getting smaller. The power supply harmonic regulation is a stricter condition for higher harmonics. In particular, in order to clear the power supply harmonic regulation in the fifth harmonic current, the shape of a substantially sine wave as shown by the waveform B It is shown that it is more advantageous to present.

  FIG. 6 is a diagram illustrating an example of a fifth-order harmonic evaluation index with respect to the ratio between the first half quiescent current period and the second half quiescent current period. In FIG. 6, the horizontal axis indicates the value of Td / To, and the vertical axis indicates the fifth harmonic evaluation index Yn. Here, the harmonic evaluation index indicates the degree of achievement of the harmonic current with respect to the standard value, and if Yn <100%, it indicates that the power supply harmonic regulation (IEC61000-3-2) is satisfied. FIG. 6 shows three graphs with different reactor inductances. Among these, the graph shown by the one-dot chain line is an example when the reactor inductance is large (for example, inductance = 12 mH), and the graph shown by the solid line is an example when the reactor inductance is small (for example, inductance = 3 mH). Is shown. The graph shown by the dotted line is an example in the case where the reactor inductance is between these (for example, inductance = 6 mH).

  In FIG. 6, when the switching operation is started from the waveform A in FIG. 4, that is, the voltage zero cross point, Td / To = 0. When the reactor inductance is large (a graph indicated by a one-dot chain line in FIG. 6), even if Td / To = 0, Yn <100% is satisfied and the power harmonic regulation is cleared, but the reactor inductance is small. Then (a graph indicated by a dotted line and a solid line in FIG. 6), it is understood that the power supply harmonic regulation cannot be satisfied. This is because when the reactor inductance is small, the energy stored in the reactor is reduced by one switching and the passive operation period is shortened. As a result, the waveform deviates from a substantially sinusoidal waveform with few harmonics. .

  On the other hand, as shown in FIG. 6, the fifth harmonic current is the smallest in the vicinity of Td / To = 1. Therefore, in the power supply device according to the first embodiment, Td / To = 1, that is, as shown in the waveform B of FIG. 4B, the first half zero input current period Td and the second half zero input current period To are equal. By controlling the switching start time td, the reactor inductance can be reduced while the power harmonic regulation is cleared. More specifically, the switching start time td is controlled so that the value of Td / To falls within the range of 0.55 to 2.20 as shown by the dotted line in FIG. The value of the evaluation index Yn is set to 100% or less. More preferably, the switching start time td is controlled so that the value of Td / To is within the range of 0.70 to 1.60, and the value of the fifth harmonic evaluation index Yn is 80% or less. By doing so, it is possible to secure a margin for the regulation value of the fifth harmonic current of the power supply harmonic regulation. For this reason, in this embodiment, a reactor having an inductance of 6 mH is employed. In addition, in a general home air conditioner having a power supply device that inputs a 200V power supply and performs switching of the reactor, a reactor having an inductance of 12 mH or more is used, and the power supply device according to the present embodiment is not used. In this case, it was difficult to clear the power harmonic regulation in a reactor having an inductance of 10 mH or less.

  Next, the operation of the power supply apparatus according to the first embodiment will be described with reference to FIGS. 1 to 3 and FIG. FIG. 7 is a timing chart for explaining the operation of the power supply apparatus according to the first embodiment. 7A shows a power supply voltage waveform of the AC power supply 1, FIG. 7B shows an input current waveform, and FIG. 7C shows a voltage zero cross point detection output from the power supply phase detection circuit 5. FIG. 7D illustrates the timing of the switching start signal output from the switching start time calculation unit 111, and FIG. 7E illustrates the switching permission output from the switching permission signal creation unit 112. Signal timing is shown.

  The power source phase detection circuit 5 detects the voltage phase of the AC power source 1 to detect a voltage zero cross point, and outputs a voltage zero cross point detection signal to the control unit 10 (see FIG. 7C). The input current detection unit 8 detects the input current of the booster circuit 3 based on the detection signal from the current sensor 6 and outputs it to the control unit 10.

  The switching operation period setting unit 110 of the control unit 10 outputs a predetermined switching operation period Ton set in advance. Note that the switching operation time setting unit 110 may calculate the switching operation period Ton according to the magnitude of the input current.

The switching start time calculation unit 111 obtains a switching start time td where the time of the voltage zero cross point is 0, for example, by the following equation (1).
td = −aI + b (1)

  In the formula (1), I is an effective value of the input current, and a and b are positive constants. According to the equation (1), the switching start time td is reduced as the input current increases, that is, the switching start is advanced. The values of the constant a and the constant b are set such that the first half zero input current period Td = the second half zero input current period To in consideration of a predetermined switching operation period Ton and passive operation period set in advance. The value of I may be an average value of input current. In addition, the values of the constant a and the constant b are calculated by the switching operation period setting unit 110 by calculating the switching operation period Ton according to the magnitude of the input current and based on the calculated switching operation period Ton. Also good. Alternatively, the switching start time td corresponding to the input current may be determined in advance and tabulated, and the switching start time td may be extracted from the detected input current value.

  The switching start time calculation unit 111 outputs a switching start signal at the switching start time td obtained by the equation (1) (see FIG. 7D). The period from when the voltage zero cross point detection signal is input to when the switching start signal is output is the first half zero input current period Td.

  The switching permission signal creation unit 112 creates and outputs a switching permission signal that permits the switching operation of the switching element 3c during a period from when the switching start signal is input at the switching start time td to when the switching operation period Ton elapses. (See FIG. 7 (e)).

  The switching pulse generation unit 114 generates a switching pulse signal and outputs it to the drive unit 7 during the period when the switching permission signal is output.

  As described above, according to the power supply device of the first embodiment, the input current is determined by the first half zero input current period from the voltage zero cross point to the zero cross point of the input current at which the input current starts to flow, and the passive operation of the reactor after the switching operation. Since the switching control is performed so that the second half zero input current period from the zero cross point of the input current where the current flows to the voltage zero cross point of the next half cycle becomes equal, the power harmonic regulation is cleared and further The reactor can be downsized.

  Further, by performing switching control so that the ratio of the first half quiescent current period to the second half quiescent current period is in the range of 0.55 to 2.20, the selection of the reactor inductance is facilitated.

  In addition, since the switching start time is advanced as the effective value or average value of the input current increases and the switching start time is delayed as the effective value or average value of the input current decreases, the effective value or average value of the input current is reduced. The above switching control can be performed following the above.

Embodiment 2. FIG.
In the second embodiment, in addition to the switching operation in the first half period of the half cycle of the power supply voltage, the switching operation is also performed in the second half period of the half cycle of the power supply voltage, so that the first half zero input current period Td and the second half zero input current period An example of shortening To and improving the power factor will be described.

  FIG. 8 is a timing chart for explaining the operation of the power supply device according to the second embodiment. 8A shows the power supply voltage waveform of the AC power supply 1, FIG. 8B shows the input current waveform, FIG. 8C shows the timing of the voltage zero cross point detection signal, and FIG. d) shows the timing of the switching start signal, and FIG. 8 (e) shows the timing of the switching permission signal. The configuration of the power supply device according to the second embodiment is the same as that of the first embodiment, and thus detailed description thereof is omitted.

In the power supply apparatus according to the second embodiment, the switching start time calculation unit 111 obtains the switching start time td1 and the switching restart time td2 with the voltage zero crossing point time set to 0, for example, by the following equations (2) and (3). .
td1 = −cI + d (2)
td2 = eI + f (3)

  In equations (2) and (3), I is an effective value of the input current, and c, d, e, and f are positive constants. According to equation (2), the switching start time td1 is advanced as the input current increases, and according to equation (3), the latter half switching resumption time td2 is delayed as the input current increases. The values of the constants c, d, e, and f are set so that the first half zero input current period Td = the second half zero input current period To in consideration of a predetermined switching operation period Ton and a passive operation period set in advance. In addition, the switching operation in the second half period of the half cycle of the power supply voltage is started in the passive operation period after the switching operation in the first half period of the half cycle of the power supply voltage. Note that the value of I may be an average value of the input current, as in the first embodiment. In addition, the values of the constants c, d, e, and f are calculated by the switching operation period setting unit 110 according to the magnitude of the input current, and the calculated switching operation is performed in the same manner as in the first embodiment. It may be calculated based on the operation period Ton. Alternatively, as in the first embodiment, the switching start time td corresponding to the input current may be determined in advance and tabulated, and the switching start time td may be extracted based on the detected input current value.

  The switching start time calculation unit 111 outputs a switching start signal at the switching start time td1 obtained by the equation (2) and the switching restart time td2 obtained by the equation (3) (see FIG. 8D). In the present embodiment, the switching operation period Ton started at td1 and td2 has the same value, but different values may be used.

  The switching permission signal creation unit 112 is configured such that a period from when the switching start signal is input at the switching start time td1 until the switching operation period Ton passes, and a switching operation period Ton after the switching start signal is input at the switching resumption time td2. A switching permission signal for permitting the switching operation of the switching element 3c is generated and output until a period of time elapses (see FIG. 8E).

  As described above, according to the power supply device of the second embodiment, switching is performed in the second half period of the half cycle of the power supply voltage in addition to the first half period of the half cycle of the power supply voltage. In addition to the effect, it becomes possible to improve the power factor.

Embodiment 3 FIG.
In the first embodiment, the switching start time td in which the first half quiescent current period Td = the second half quiescent current period To is calculated according to the effective value or average value of the input current, and the switching start signal after the switching start time td has elapsed. In the case where the input current fluctuates rapidly due to load fluctuation, for example, the balance between the first half quiescent current period Td and the second half quiescent current period To may be lost, and the harmonic current may increase. There is sex. Therefore, in the third embodiment, an example in which the switching start time td is calculated by calculating the average value of the first half quiescent current period Td and the second half quiescent current period To in the half cycle immediately before the switching control target period will be described. .

  FIG. 9 is a timing chart for explaining the operation of the power supply device according to the third embodiment. 9A shows the power supply voltage waveform of the AC power supply 1, FIG. 9B shows the input current waveform, FIG. 9C shows the timing of the voltage zero cross point detection signal, and FIG. d) shows the timing of the switching start signal, and FIG. 9 (e) shows the timing of the switching permission signal. Since the configuration of the power supply device according to the third embodiment is the same as that of the first and second embodiments, detailed description thereof is omitted.

  In the power supply device according to the third embodiment, the switching start time calculation unit 111 detects the zero-cross point of the input current after passive operation every half cycle of the power supply voltage, starts counting, and then starts the voltage zero-cross of the next half cycle. The count is stopped when the point detection signal is input.

  The counted period is defined as the latter half zero input current period To in the immediately preceding half cycle, and the average of the period from the voltage zero cross point to the switching start time td in the immediately preceding half cycle, that is, the former half zero input current period Td is calculated. Using this average value (Td + To) / 2 as the first half quiescent current period Td ′ of the switching control target period, the switching start time td ′ is calculated (see FIG. 9).

  Thereby, even when the input current fluctuates abruptly, the first half quiescent current period Td 'and the second half quiescent current period To' can be controlled to be equal.

  Note that the values of Td and To used for calculating the switching start time td ′ are preferably values immediately before the switching control target period or in a half cycle about several cycles before. Depending on the processing speed of a computer or the like, it may be a value of a half cycle of several tens of cycles or earlier.

  As described above, according to the power supply device of the third embodiment, the average value of the first half quiescent current period and the second half quiescent current period in the half cycle immediately before the switching control target period is calculated to calculate the switching control target period. Since the switching start time is calculated, the harmonic current can be suppressed even when the input current fluctuates rapidly.

  Note that the configuration shown in the above embodiment is an example of the configuration of the present invention, and can be combined with another known technique, and a part thereof is omitted without departing from the gist of the present invention. Needless to say, it is possible to change the configuration.

  As described above, the power supply device according to the present invention is useful as an invention that can further reduce the size of the reactor while clearing the power harmonic regulation.

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Rectifier circuit 3 Booster circuit 3a Reactor 3b, 3b1, 3b2 Diode 3c Switching element 4 Load 5 Power supply phase detection circuit 6 Current sensor 7 Drive part 8 Input current detection part 10 Control part 11 Smoothing capacitor 110 Switching operation period setting part DESCRIPTION OF SYMBOLS 111 Switching start time calculation part 112 Switching permission signal preparation part 113 Current command value calculation part 114 Switching pulse generation part 150 Current command value preparation circuit 400 Comparator 500 Logic circuit

Claims (6)

When converting the AC power source into a DC voltage to be a load voltage, the AC power source is short-circuited by a switching element through a reactor to improve the power factor,
A booster circuit including the switching element;
A power supply phase detection circuit for detecting a voltage zero cross point of the AC power supply by detecting a voltage phase of the AC power supply;
An input current detector for detecting an input current of the booster circuit;
Based on the voltage zero-crossing point and the input current, a control unit for switching the switching element in a predetermined switching operation period;
A drive unit that drives the switching element based on a switching pulse output from the control unit;
With
The control unit considers the predetermined switching operation period and the passive operation period after the predetermined switching operation period for each half cycle of the AC power source indicated by two successive voltage zero cross points, The first half zero input current period from the voltage zero cross point to the zero cross point of the input current where the input current begins to flow, and the second half zero input from the zero cross point of the input current where the input current ends to the next voltage zero cross point A switching start time for starting the switching operation is determined so that the current period is equal, the switching operation is started at the switching start time, and the switching operation is stopped after the predetermined switching operation period has elapsed. A power supply device characterized by that. When converting the AC power source into a DC voltage to be a load voltage, the AC power source is short-circuited by a switching element through a reactor to improve the power factor,
A booster circuit including the switching element;
A power supply phase detection circuit for detecting a voltage zero cross point of the AC power supply by detecting a voltage phase of the AC power supply;
An input current detector for detecting an input current of the booster circuit;
Based on the voltage zero-crossing point and the input current, a control unit for switching the switching element in a predetermined switching operation period;
A drive unit that drives the switching element based on a switching pulse output from the control unit;
With
The control unit considers the predetermined switching operation period and the passive operation period after the predetermined switching operation period for each half cycle of the AC power source indicated by two successive voltage zero cross points, During the first half zero input current period from the voltage zero cross point to the zero cross point of the input current where the input current begins to flow, the second half zero input from the zero cross point of the input current where the input current ends to the next voltage zero cross point A switching start time for starting the switching operation is determined so that a ratio to a current period is in a range of 0.55 to 2.20, the switching operation is started at the switching start time, and the predetermined switching is performed. A power supply characterized in that the switching operation is stopped after an operation period has elapsed. apparatus.   2. The control unit according to claim 1, wherein the switching start time is advanced as the effective value or average value of the input current increases, and the switching start time is delayed as the effective value or average value of the input current decreases. Or the power supply device of 2.   The control unit further determines a switching restart time for restarting the switching operation in the passive operation period, restarts the switching operation in the switching restart time, and performs the switching operation after the predetermined switching operation time elapses. The power supply device according to claim 1, wherein the power supply device is stopped.   5. The control unit delays the switching restart time as the effective value or average value of the input current increases, and accelerates the switching restart time as the effective value or average value of the input current decreases. The power supply device described in 1.   The control unit calculates an average value of the first half quiescent current period in a half cycle before the switching control target period and the second half quiescent current period in the half cycle, and calculates the average value from the voltage zero cross point. 4. The power supply device according to claim 1, wherein a time when the time elapses is set as the switching start time of the switching control target period.

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