JP3475688B2 - Power converter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter that uses a power supply unit that generates an AC voltage having a discontinuous waveform and that can adjust the power supplied to a load.

[0002]

2. Description of the Related Art The inventor of the present invention has heretofore proposed a power converter for converting power from direct current to alternating current by using a switched capacitor and an inverter circuit together. FIG. 10 shows an example of this type of power conversion device. As the switched capacitors, three capacitors C ₁ to
The one with C ₃ is shown. A charging switching element S ₁ is inserted between the positive electrode of the DC power source E and the capacitor C _1, and a charging switching element S is inserted between the capacitors C ₂ , C ₃ and each pole of the DC power source E. ₂ ~
S ₅ is inserted. Further, each of the capacitors C _{1 to} C ₃
Charging switching element S ₁ and, S _2, the discharging switching element S ₈ to S ₁₀ that connects the other end is connected at one end to the common connection point between S ₄ provided, the positive electrode and the capacitor C ₂ of the capacitor C ₁ The discharging switching elements S ₆ and S ₇ are inserted between the negative electrode of the capacitor C _{2 and} the positive electrode of the capacitor C ₂ and the negative electrode of the capacitor C ₃ , respectively. Charging switching elements S _{1 to} S ₅ and discharging switching element S ₆ to
The timing of turning on / off S ₁₀ is the timing control circuit CN.
Controlled by, the potential at the connection point where the discharge switching elements S _{8 to} S ₁₀ are commonly connected is changed stepwise.

On the other hand, the inverter circuit is a switching element.
A bridge connection of the children Sa to Sd, each of which
Each arm in which switching elements Sa to Sd are connected in series
Switching elements Sa, Sb and Sc, Sd in
Leakage transformer T between the connection points of₁Primary winding and
Capacitor C_FourConnect the parallel circuit of the
Su T₁A load 3 is connected to the secondary winding of the. Of this kind
Inverter circuits are well known and
Switching elements Sa, Sd and diagonally arranged
And a period to turn on Sb and Sc at the same time is provided.
To the switching elements Sa, Sb and S of each arm.
Control so that c and Sd do not turn on at the same time, and
A period and a switch for simultaneously turning on the switching elements Sa and Sd
The period during which the switching elements Sb and Sc are turned on at the same time
The voltage applied to the load 3 is generated by alternating generation.
It is designed to alternate the polarity of pressure. Switching
Turning on / off of the elements Sa to Sd charges the switched capacitor.
Electric switching element S₁~ S _FiveAnd switching for discharge
Element S₆~ S_TenAs with the timing control circuit CN
Controlled.

Therefore, the switched capacitor can generate a voltage that changes stepwise, and the inverter circuit can alternate the polarity of the voltage applied to the load 3. Therefore, the switched capacitor and the inverter circuit are appropriately controlled. As a result, it is possible to apply a sinusoidal AC voltage that changes stepwise (that is, a discontinuous waveform) to the load 3.

By the way, the timing control circuit CN includes switching elements S _{1 to} S ₅ for charging, switching elements S _{6 to} S ₁₀ for discharging, and switching elements Sa to Sd as shown in FIG.
The control is performed at the timing shown in 1. Now, the operation will be described assuming that the circuit shown in FIG. 10 is performing a steady operation. First, at time t ₀ , all of the charging switching elements S _{1 to} S ₅ are turned on and the discharging switching element S ₁₀ is turned on. At this time, each capacitor C ₁
Voltage across -C ₃ is charged to a voltage substantially equal to the voltage across the DC power source E, the voltage V ₁ applied to the inverter circuit is substantially equal to the voltage of the DC power source E as shown in FIG. 11 (o).

Next, at time t ₁ , all the charging switching elements S _{1 to} S ₅ are turned off, and only the discharging switching elements S ₆ and S ₉ are turned on. by this,
The capacitors C ₁ and C ₂ are connected in series, and the voltage V ₁ applied to the inverter circuit is approximately 2 times the voltage across the DC power source E.
Double. In yet time t _2, the turn off the discharge switching element S ₉ from this state, when turning on the switching element S _7, S _8, all the capacitors C ₁ ~
Since C ₃ is connected in series, the voltage V ₁ applied to the inverter circuit is almost three times the voltage across the DC power source E.

Time t₃At time t₁In the same state as
Set, time t_FourAt time t ₀Set to the same state as
To do. Also, at time t_FiveThen time t_FourKeep the state of
One. After that, by repeating the above operation,
Voltage V applied to the data circuit ₁Voltage goes up and down in a staircase
It becomes a pulsating current wave shape. On the other hand, configure the inverter circuit
The switching elements Sa to Sd are shown in FIGS.
As shown in FIG.₁~
S_FiveAnd discharge switching element S₆~ S_TenPeriod t
₀~ T_FiveThe leakage transformer T₂
The polarity of the voltage applied to is reversed. That is, the period t₀~
t_FiveTurns on the switching elements Sa and Sd,
The switching elements Sb and Sc are turned off during the period t_Five~ T
_TenTurns off the switching elements Sa and Sd, and switches
The elements Sb and Sc are turned on. Like this
Leakage Transformer T ₁Voltage applied to the primary winding of
The voltage changes stepwise and the sine wave as a whole
The voltage will change to an AC waveform.

As is clear from the above description, the charging switching element S ₁ which constitutes a switched capacitor.
To S ₅ and discharging switching element _S 6 _{to S 10}
And a switching element Sa constituting the inverter circuit
Sd is controlled so as to interlock with each other. Here, the voltage applied to the leakage transformer T ₁ changes stepwise, but the leakage transformer T ₁
Since the leakage component of C and the capacitor C ₄ function as a filter, the stepwise discontinuous waveform of the switched capacitor can be shaped into a substantially continuous waveform as shown in FIG. The corrugated AC voltage V ₂ can be applied to the load 3. Further, the voltage applied to the load 3 can be designed to a desired value by appropriately setting the turn ratio of the leakage transformer T ₁ .

In this circuit configuration, the switching element S ₁
To S _10, by increasing the frequency for switching Sa to Sd, because it is possible to reduce the energy of a single charging and discharging of each capacitor C ₁ -C _3, reducing the capacitance of the capacitor C ₁ -C ₃ Therefore, it is possible to provide a small power conversion device.

[0010]

By the way, in order to adjust the voltage applied to the load 3 in the above configuration, it is conceivable to make the output voltage of the DC power source E variable as shown in FIG. However, if the output voltage of the DC power source E is made variable in this way, the DC power source E with a special configuration is used.
Therefore, there arises a problem that the device becomes large and the power conversion efficiency decreases.

The present invention has been made in view of the above circumstances, and an object thereof is to adopt a configuration for controlling an output voltage waveform of a power supply section without using a special configuration as a DC power supply. An object of the present invention is to provide a power conversion device capable of adjusting the power supplied to a load without increasing the size of the device or reducing the power conversion efficiency.

[0012]

According to a first aspect of the present invention, a power supply section for outputting an alternating current having a discontinuous sinusoidal waveform and an output voltage waveform of the power supply section are shaped into a substantially continuous waveform to supply power to a load.
And a filter element for supplying, through the filter element by varying the frequency component ratio of the output voltage of the power supply unit
The electric power to be supplied to the load is adjusted by changing the passing electric power . According to this configuration, since the amount of power passing through the filter element is adjusted by controlling the waveform of the output voltage of the power supply unit, it is not necessary to use a special power supply for the power supply unit, and the output voltage of the power supply unit is not required. The power supplied to the load can be easily adjusted only by adopting a circuit configuration capable of changing the waveform. As a result, it becomes possible to adjust the power supplied to the load without increasing the size of the device or reducing the power conversion efficiency.

According to a second aspect of the present invention, in the first aspect of the invention, the filter element is a piezoelectric transformer.
According to this configuration, since a small filter element is used, it is possible to reduce the size and height.
According to a third aspect of the present invention, in the first or second aspect of the invention, the power source section includes a plurality of capacitors, a charging switching element inserted in a charging path from the DC power source to the capacitors, and the capacitor to the piezoelectric transformer. Control circuit for controlling the discharge switching element inserted in the discharge path to the discharge path and the on / off timing of the charge switching element and the discharge switching element to change the output voltage waveform stepwise The output voltage of the switched capacitor includes an inverter circuit for inverting the polarity of the output voltage of the switched capacitor for each cycle of the pulsating current waveform and applying the result to the piezoelectric transformer. The frequency component ratio of is changed. According to this configuration, the power supply unit can be downsized, and the output voltage waveform can be easily controlled only by controlling the operation timing of the switching element.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the discharge lamp is used as a load, and the filter element outputs a voltage capable of stably maintaining lighting of the discharge lamp. This configuration is the preferred embodiment. According to a fifth aspect of the present invention, the piezoelectric element is provided with an output electrode at a predetermined distance from a power source section that outputs an alternating current having a discontinuous sinusoidal waveform, and a drive section that is provided with a pair of input electrodes facing each other with the piezoelectric element interposed therebetween. And a piezoelectric transformer that shapes the output voltage waveform of the power supply unit into a substantially continuous waveform and that converts the output voltage of the power supply unit into a voltage and applies it to the load. A plurality of capacitors, a charging switching element inserted in the charging path from the DC power supply to the capacitor, a discharging switching element inserted in the discharging path from the capacitor to the piezoelectric transformer, a charging switching element and a discharging switching The timing control circuit has a pulsating current waveform in which the output voltage waveform changes stepwise by controlling the on / off timing of the element. Provided with a Tsu Tito capacitor,
The polarity of the output voltage of the switched capacitor is 1
An inverter circuit which inverts every cycle and applies it to the piezoelectric transformer is provided, and the frequency component ratio of the output voltage is changed by controlling the timing by the timing control circuit. According to this structure, the same effects as those of the inventions of claims 1 to 3 are obtained.

According to a sixth aspect of the invention, in the first to fifth aspects of the invention, the output voltage of the power supply unit has a pause period and the pause period is adjustable. This configuration is the preferred embodiment.

[0016]

DETAILED DESCRIPTION OF THE INVENTION

(Embodiment 1) As the circuit of this embodiment, as shown in FIG. 1A, the same circuit as that shown in FIG. 10 is used. That is, the switched capacitor and the inverter circuit constitute the power supply unit. However, the output voltage of the DC power source E is constant. This embodiment by controlling the ON period of the discharging switching element S ₆ to S ₈ of the timing control circuit CN, it is characterized by controlling the power supplied to the load 3.

That is, the circuit in the circuit shown in FIG.
-Cage transformer T₁The voltage applied to the primary winding of the
It has a stepwise discontinuous waveform as shown in (b)
The body is almost sinusoidal alternating current. here
Then, the switching element S for discharge ₆~ S₈Control the ON period of
The absolute value of the voltage is the most
Higher period W₁Will change.

Now, the staircase waveform shown in FIG. 1 becomes a sine wave.
Closest state (that is, the basics contained in the staircase waveform
From the state where the wave component is maximum) to the period W₁Direction to shorten
Suppose you changed to. In this case, it is included in the staircase waveform
High frequency components will increase. That is, the period W₁But
Shortening reduces the total energy per cycle
As the number decreases, the fundamental wave component decreases and the high frequency component
Will increase. Now, change the staircase waveform to the frequency of the fundamental wave component.
If it is expressed by the sum of components that are integral multiples of a certain fundamental frequency,
(Fourier transform etc. may be applied), as shown in FIG.
And the fundamental frequency f ₀And an integral multiple component f of the fundamental frequency₁, F
₂, ........ Frequency components included in the stepped waveform by the component ratio of
Can be shown. Then, period W₁To change
If the previous frequency component had the relationship shown by the solid line in FIG.
, Period W₁If is shortened, the frequency component is shown by the broken line in Fig. 2.
The relationship will change.

On the other hand, the path for supplying electric power to the load 3 is free.
Leakage transformer T that functions as a filter element₁And
And capacitor C_FourSince it is provided,
Su T ₁Frequency component of the staircase waveform applied to the primary winding of
If is changed, the power passing through the filter is changed and the result
As a result, the power supplied to the load 3 also changes. Take
In addition, the timing can be changed without changing the output voltage of the DC power supply E.
Supply to the load 3 only by the control of the switching control circuit CN.
It becomes possible to adjust the force. As a result, the equipment is large
Without reducing the power conversion efficiency or reducing the power conversion efficiency.
The power supplied to the load 3 can be easily adjusted. other
The structure and operation are similar to those shown in FIG.

By the way, in the configuration shown in FIG.
Page transformer T₁The voltage applied to the primary winding of the
It has a staircase wave shape that changes. Therefore, the maximum voltage period
W ₁Instead of changing
Voltage period W between₂Or more as shown in Figure 4
Low voltage period W₃It is also possible to change.
Also in these cases, the period W₂, W₃By controlling
The power supplied to the load 3 can be adjusted by adjusting the load.

Further, when the period W _{3 of the} lowest voltage is changed, a pause period T may be provided before and after the polarity is inverted as shown in FIG. The frequency component ratio can also be changed by changing the rest period T. Since this control can be realized only by controlling the ON period of the switching element ₉ , the control is simple.

The periods W _{1 to} W ₃ may be controlled in any combination. Further, the switching of the states of the respective switching elements S _{1 to} S ₁₀ forming the switched capacitor does not have to be performed at fixed time intervals, and the time intervals may be changed appropriately. In other words, the half-cycle voltage waveform is symmetrical in the one shown in FIG. 10, but may be asymmetrical.

(Embodiment 2) In this embodiment, as shown in FIG. 6, a piezoelectric transformer T ₂ is used instead of the leakage transformer T ₁ . The piezoelectric transformer T ₂ includes a pair of input electrodes 1 at one end in the longitudinal direction of a rectangular parallelepiped piezoelectric element 11.
2a and 12b are provided facing each other, and the output electrode 13 is provided on the other end face in the longitudinal direction. Both input electrodes 12
Between a and 12b functions as the drive unit 15, and the drive unit 15
The power generation unit 16 is formed between the output electrode 13 and the output electrode 13.

The piezoelectric transformer T ₂ causes a mechanical vibration in the piezoelectric element 11 by applying an AC voltage to the drive section 15, and the voltage generated by this mechanical vibration is applied to the output electrode 1.
It was taken out from 3. Since mechanical vibration has inertia, it equivalently functions as a filter circuit. The piezoelectric transformer T ₂ has a resonance frequency according to the length of the power generation section 16,
A voltage having a frequency close to this resonance frequency is applied to the input electrode 12a,
By applying the voltage to 12b to cause the piezoelectric element 11 to resonate, it is possible to obtain a greatly boosted voltage from the output electrode 13.

As described above, since the piezoelectric transformer T ₂ has both the function as a filter element and the function as a transformer element, the piezoelectric transformer T ₂ can act as a filter without providing the capacitor C ₄ . Moreover, the piezoelectric transformer T ₂ can be downsized as compared with a transformer in which a winding is provided on an iron core, which leads to downsizing or a low profile (thinning) as a whole.

The other structure is the same as that shown in FIG. However, the timing control circuit CN is not shown in the figure. The switching timing of each of the switching elements S _{1 to} S ₁₀ is the same as that in the first embodiment. (Embodiment 3) In this embodiment, as shown in FIG. 7, a discharge lamp 31 having a cold cathode 32 is used as a load 3 in the configuration of Embodiment 2, and a capacitor C _{5 is provided} between both ends of the discharge lamp 31.
Is connected. With this configuration, a high voltage is required at the time of starting the discharge lamp 31, but by using the piezoelectric transformer T ₂ , it is possible to obtain a high boosting ratio in spite of its small size,
As a result, it is possible to provide a small device. Other configurations and operations are similar to those of the second embodiment.

(Embodiment 4) In this embodiment, as shown in FIG. 8, in the configuration of Embodiment 2 shown in FIG. 6, the switched capacitor is omitted and the capacitor C _{4 is provided} on the primary side of the piezoelectric transformer T _2. Are connected in parallel, and a series circuit of a capacitor C ₄ and an inductor L ₁ is connected between the output terminals of the inverter circuit. In short, the inverter circuit is used to obtain a rectangular wave AC voltage from the DC power source E,
This AC voltage is passed through a filter and the piezoelectric transformer T
It is transformed by ₂ and supplied to the load 3. The switching elements Sa to Sd are controlled by a timing control circuit (not shown).

However, the operation timing of each of the switching elements Sa to Sd forming the inverter circuit is set as shown in FIG. That is, the switching elements Sa, Sb and Sc, Sd connected in series in each arm of the bridge circuit are alternately turned on and off, and the switching elements Sa, Sd and Sb, Sc provided at diagonal positions are turned on at the same time. Before and after, there is a period in which only one of them is turned on. If it described with reference to FIG. 9, the period t ₁ ~t
₂ , the switching elements Sa and Sd are turned on, and as shown in FIG.
Since the point A in FIG.
As in (e), a positive voltage is applied between points A and B. Next, since the switching elements Sb and Sd are turned on in the periods t _{2 to} t ₃ , both the points A and B are negative and no voltage is applied between the points A and B, and the periods t ₃ to t ₃ . When the switching elements Sb and Sc are turned on at t ₄ , the point A becomes a negative electrode and the point B becomes a positive electrode, so that as shown in FIG.
A negative voltage is applied between points B. Then, the period t _{4 to} t ₅
Then, since the switching elements Sa and Sd are turned on, A
Both points and B are positive and no voltage is applied between points A and B. In this way, a voltage having a substantially continuous voltage waveform as shown in FIG. 9F can be applied to the load 3.

As described above, the voltage between the points A and B has a voltage waveform in which positive and negative are alternately repeated with the output voltage of the DC power source E as an absolute value, and a rest period exists between the positive and negative inversions. . Therefore, if the phase difference θ of control between the switching elements Sa and Sb and the switching elements Sc and Sd is adjusted by the timing control circuit, the period W ₀ during which the voltage is applied between the points A and B can be changed. it can. If the period W ₀ changes, the frequency component included in the voltage waveform applied between the points A and B changes, and the supplied power per unit time also changes. As a result, the supplied power to the load 3 is changed. Can be changed.

By the way, since the piezoelectric transformer T ₂ generally has a capacitive component, an inrush current may flow when the output voltage of the inverter circuit is applied. However, in the circuit configuration of this embodiment, the piezoelectric transformer T 2 is used. _By connecting the inductor L ₁ in series with the parallel circuit of the capacitor ₂ and the capacitor C _4, a choke input type circuit is formed, and the inrush current can be reduced. Therefore, it is possible to suppress the generation of stress and noise due to the inrush current.

[0031]

According to the first aspect of the present invention, a power supply section for outputting an alternating current having a discontinuous sinusoidal waveform and a power supply section for shaping an output voltage waveform of the power supply section into a substantially continuous waveform and supplying electric power to a load. and a filter element, the power passing through the filter element is changed by changing the frequency component ratio of the output voltage of the power supply section.
The power supplied to the load is adjusted by this, and the amount of power passing through the filter element is adjusted by controlling the waveform of the output voltage of the power supply unit. There is an advantage that the power supply to the load can be easily adjusted only by adopting a circuit configuration capable of changing the output voltage waveform as the power supply section without using a power supply unit. As a result, it becomes possible to adjust the power supplied to the load without increasing the size of the device or reducing the power conversion efficiency.

When the filter element is formed of a piezoelectric transformer as in the second aspect of the invention, a small size filter element is used, so that there is an advantage that the size and the height can be reduced. According to a third aspect of the present invention, the power supply unit includes a plurality of capacitors, a switching element for charging inserted in a charging path from the DC power supply to the capacitor, and a discharge inserted in a discharging path from the capacitor to the piezoelectric transformer. And a switched capacitor comprising a switching element for charging and a timing control circuit for controlling the on / off timings of the charging switching element and the discharging switching element to change the output voltage waveform stepwise to form a pulsating current waveform. An inverter circuit that inverts the polarity of the output voltage of the output signal for each cycle of the pulsating waveform and applies it to the piezoelectric transformer is provided, and the frequency component ratio of the output voltage is changed by controlling the timing by the timing control circuit. , It is possible to downsize the power supply unit and There is an advantage that it is possible to easily control the output voltage waveform only by controlling the operation timing of the device.

According to a fifth aspect of the present invention, the power source section for outputting alternating current having a discontinuous sinusoidal waveform and the driving section in which a pair of input electrodes are opposed to each other with the piezoelectric element interposed therebetween are separated by a predetermined distance and output to the piezoelectric element. This is a transformer in which the power generation part is formed with electrodes, and the output voltage waveform of the power supply part is adjusted to a substantially continuous waveform.
And a piezoelectric transformer that converts the output voltage of the power supply unit and applies it to the load, and the power supply unit includes a plurality of capacitors and a charging switching element inserted in a charging path from the DC power supply to the capacitors. , A pulsating wave shape that changes the output voltage waveform stepwise by controlling the on / off timing of the discharging switching element inserted in the discharging path from the capacitor to the piezoelectric transformer and the charging switching element and the discharging switching element And a timing control circuit, and an inverter circuit for inverting the polarity of the output voltage of the switched capacitor for each cycle of the pulsating flow waveform and applying the result to the piezoelectric transformer. The frequency component ratio of the output voltage can be changed by controlling it. A shall, the same effects as the invention of claims 1 to 3.

[Brief description of drawings]

FIG. 1 shows the first embodiment, (a) is a circuit diagram, and (b) is an operation explanatory diagram.

FIG. 2 is an operation explanatory diagram of the first embodiment.

FIG. 3 is another operation explanatory diagram of the first embodiment.

FIG. 4 is a diagram illustrating still another operation according to the first embodiment.

FIG. 5 is another operation explanatory diagram of the first embodiment.

FIG. 6 is a circuit diagram showing a second embodiment.

FIG. 7 is a main part circuit diagram showing a third embodiment.

FIG. 8 is a circuit diagram showing a fourth embodiment.

FIG. 9 is an operation explanatory diagram of the fourth embodiment.

FIG. 10 is a circuit diagram showing a tenth embodiment.

FIG. 11 is an operation explanatory diagram of the above.

[Explanation of symbols]

3 load 11 piezoelectric element 12a, 12b input electrode 13 output electrode 15 drive unit 16 power generation unit 31 discharge lamp C _{1 to} C ₃ capacitor CN timing control circuit E DC power supply S _{1 to} S ₅ charging switching element S _{6 to} S ₁₀ discharge Switching element Sa to Sd switching element T ₁ leakage transformer T ₂ piezoelectric transformer

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02M 7/48 H02M 11/00

Claims (6)

(57) [Claims] 1. A power supply section for outputting alternating current of a discontinuous sinusoidal waveform, and an output voltage waveform of the power supply section into a substantially continuous waveform.
With a filter element that shapes and supplies power to the load ,
A power converter characterized in that the power passing through the filter element is changed by changing the frequency component ratio of the output voltage of the power supply unit, and thereby the power supplied to the load is adjusted. 2. The power converter according to claim 1, wherein the filter element is a piezoelectric transformer. 3. The power supply section includes a plurality of capacitors, a charging switching element inserted in a charging path from the DC power source to the capacitor, and a discharging switching element inserted in a discharging path from the capacitor to the piezoelectric transformer. An output voltage of the switched capacitor comprising a timing control circuit having a pulsating wave shape in which the output voltage waveform is changed stepwise by controlling the on / off timing of the charging switching element and the discharging switching element. An inverter circuit for inverting the polarity of the pulse waveform for each cycle of the pulsating waveform and applying it to the piezoelectric transformer, and changing the frequency component ratio of the output voltage by controlling the timing by the timing control circuit. The power conversion device according to claim 1 or 2. 4. The power conversion device according to claim 1, wherein the discharge lamp is used as a load, and the filter element outputs a voltage capable of stably keeping the discharge lamp lit. 5. A piezoelectric element is provided with an output electrode at a predetermined distance from a power source section for outputting an alternating current having a discontinuous sinusoidal waveform and a driving section in which a pair of input electrodes are arranged so as to sandwich the piezoelectric element so as to generate electricity. And a piezoelectric transformer that shapes the output voltage waveform of the power supply unit into a substantially continuous waveform and converts the output voltage of the power supply unit to a load to apply it to the load. Of the capacitor, the charging switching element inserted in the charging path from the DC power supply to the capacitor, the discharging switching element inserted in the discharging path from the capacitor to the piezoelectric transformer, the charging switching element and the discharging switching element A switch composed of a timing control circuit having a pulsating flow waveform in which the output voltage waveform is changed stepwise by controlling the on / off timing. The output voltage of the switched capacitor by inverting the polarity of the output voltage of the switched capacitor for each cycle of the pulsating current waveform and applying it to the piezoelectric transformer, and controlling the timing by the timing control circuit. A power converter characterized by changing a component ratio. 6. The power conversion device according to claim 1, wherein the power supply unit has an output voltage having a rest period and the rest period is adjustable.