JPH01174274A - Power converter and controlling method thereof - Google Patents

Abstract

PURPOSE:To manufacture a compact and lightweight converter by connecting a resonance circuit of a converter with a smoothing capacitor in parallel and matching the resonance point to a frequency equal to twice as many as power frequency. CONSTITUTION:A power converter is constituted of a pulse width modulation controlling converter CONV, an AC reactor LS, a DC smoothing capacitor Cd, resonance circuits RF-CF and a load device LOAD. A controlling circuit is equipped with a current detector CT, comparators C1 and C2, a multiplier ML, a voltage control compensating circuit GV, a current control compensating circuit GI, a feed forward control operator FF and a pulse width modulation controlling circuit PWM. Voltage Vd of the capacitor Cd is detected through an insulating amplifier and so on, and is controlled through the voltage control compensating circuit GV and so on. The resonance frequency of the resonance circuits is twice as many as power frequency, the impedance at the frequency is only the one for resistance only, and is stabilized against external disturbance and others.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power conversion device with 14 pulse width modulation control that receives power from a single-phase AC power supply and a control method thereof.

[Prior Art] Load devices using a DC voltage source as a power source include a pulse width modulation control inverter + induction motor, or a DC cheater + DC motor. There is no problem when using a battery as this DC voltage source, but when obtaining DC voltage from a commercial power source via an AC/DC power converter, reactive power and harmonics generated on the commercial power source side have recently been increasing. It's becoming a problem.

In order to solve this problem, a method was proposed in which a pulse width modulation control (PwM) converter is inserted between the commercial power supply and the DC voltage source (capacitor) as an AC/DC power converter. has been done.

FIG. 7 shows a configuration diagram of a conventional power converter using a liquor converter as an AC/DC power converter.

In the figure, SUP is a single-phase AC power supply, L is an AC reactor,
C0NV is an AC/DC power converter, Cd is a DC smoothing capacitor, and LoAD is a load device.

Converter C0NV includes elements with self-extinguishing capability (e.g. dirt turn-off thyristor) S, ~S4, wheeling diodes D, ~D, and DC reactor L,
The above elements S, ~S, are composed of L2, and the AC side voltage VO
In order to control the value, a known Knolls width modulation control is performed. In other words, converter C0NV performs pulse width modulation control (
PWM) with inverter, in that case AC power supply SUP
The side can be seen as a kind of load.

This conventional power converter has a voltage V of the DC voltage source Cd.
The current 1. is supplied from the AC power source so that d is approximately constant. (1) It is capable of four-quadrant operation according to the power demand from the load device LEAD.

■ Above input current! , is always controlled to be in phase with the power supply voltage V, and the input power factor is 1.

■ Also, since the input current is controlled in a sinusoidal manner,
Harmonics become extremely small.

is a feature.

The control operation of this device will be briefly explained below.

The following control circuits are available.

CT is an AC current detector, R, and R2 are voltage dividing resistors for detecting DC voltage, ISO is an isolation amplifier, VR is a DC voltage setting device, C1 to C6 are comparators, and Cv (S) is a voltage control. Compensation circuit, ML is a multiplier, OA is an inverting operational amplifier, G
, (S) is a current control compensation circuit, TRG is a carrier wave (triangular wave) generator, and GC is a dart control circuit.

First, the DC voltage vd detected through the isolation amplifier 180t and the voltage command value vd* from the voltage setter VR are input to the comparator C1, and the deviation g, == Vd rate - Vd is determined.

The deviation is input to the control compensation circuit Gv(S), where it is integrally amplified or comparatively amplified, and the input current 1. becomes the peak value command In1.

The peak value command In1 is input to the multiplier MLK, and the multiplier is combined with the other input/output ωt. The input signal ratio ωt is obtained by detecting the power supply voltage V with a 9-unit sine wave in synchronization with the power supply voltage v,=vtn−ωt, and multiplying it by a constant (17V,
, times).

The output signal of the multiplier ML, *, gives a command value of the current to be supplied from the power supply, and is expressed by the following equation.

■ -1・-ωt ・・・・・・・・・
... (1) The relevant input current command value 1. * is inverted by the inverting amplifier OA, and the power supply S is output from the converter CON'v.
AC current supplied to UP! , 60 command value engineering. It becomes ne. Below, here! . * is called the converter output current command value.

Converter output current X is detected by alternating current detector CT0 and input to comparator C2. Comparator C2 converts the command value le* and the detected value! . are compared, and *-deviation 8□-1,I is determined. The deviation 1 is input to the next control compensation circuit G□ (8), where it is proportionally amplified and becomes a control input signal e (for pulse width modulation control).

Pulse width modulation control is performed using a known method, using a carrier wave generator τRG.
, comparator CJ, and dart control circuit GC perform this control.

In other words, the carrier wave generator TRG generates a triangular wave e? with a frequency of about 1 kHz. The comparator C5 then compares the triangular wave eT and the input signal e, and calculates the deviation '?'. =el-〇? In accordance with the r-) control circuit GC, on/off signals are given to the dirt turn-off thyristors S, ~S,.

When e, > e, that is, when the deviation C1 is positive,
Thyristors S and Sj are turned on (at this time S, S.

(off)) The AC output voltages of the controllers are v, Fi + vd.

Also, when eI < e, that is, the deviation t? When is negative, thyristors S2 and S are turned on (at this time, s, ,
s is off), vo=-v.

Moreover, if el is a large positive value, the on-periods of S and 84 become long, the on-periods of s2 and S become short, and the average value of vo becomes a positive voltage proportional to the input signal eQ. value. Conversely, if the town is a negative value, S.

The on-periods of S2 and S are longer than the on-periods of S2 and S, and the average value of the output voltage v0 of the converter is a negative value proportional to the input signal ei.

In other words, the output voltage v0 of the converter is controlled to have nine values in proportion to the input signal ei.

The output current I, (the inverse of the input current supplied by the power supply!) of the converter is controlled by adjusting the output voltage vc of the converter.

The AC reactor L has a differential voltage vL:I+:v, -v0 between the power supply voltage Vo and the output voltage v0 of the converter.
is applied.

When V, > V, the power supply current increases in the direction of the arrow in the figure. In other words, the converter output current I0° decreases in the direction of the arrow in the figure. On the contrary, V, <
V, the converter output current I0 works to increase in the direction of the arrow in the figure.

Actual current I0 for converter output current command value I0*
is in the relationship I=, * > Io, the deviation CX=I
o*−”o becomes a positive value, and the control compensation circuit Gx(S)t
-, through which the input signal elk of the PWM control is increased. Therefore, the converter output voltage V. The converter output current is also large in proportion to the input signal e, Vo>V.

Increase in the direction of the arrow in the figure. Conversely, if ゎ*<Ic, the deviation g will be a negative value, right? Decrease el or vo. Therefore, the output current of Coipata.

is its command value. Controlled to match *.

The relevant command value. If * changes in a sine wave pattern, the actual current will follow! . is also controlled in a sinusoidal manner.

Converter output current! . is the inverted value of the input current 1 from the power supply, and the command value I0 of the converter output current is
* is the command value of the input current from the power supply! , * is the inverted value. Therefore, the input current X is controlled to follow the command value 17.

Next, the control operation of the voltage vd of the DC capacitor Cd will be explained.

The comparator C4 compares the detected DC voltage value V and its command value vd*. If vd*>vdo, the deviation is a positive value, and the input current peak value is calculated via the control compensation circuit GV(S)'. increase. Input current command value, * is (
As shown in equation 1), it is given by a sine wave that is in phase with the power supply voltage. Therefore, as mentioned above, the actual input current I8 is +8: I
, ”, when the above-mentioned peak value AE is a positive value, the active power P expressed by the following equation is the single-phase power supply SU
DC capacitor cd from P via converter CoNV
is supplied to

P, = V, X I.

=vm・E・(−ωt)2 =vm・Im・(1crs2ωt)/2 −・・−(
2) Therefore, the energy P, t is the direct current capacitor cd
is accumulated as +4 Cd vd2, and as a result, the DC voltage vd increases.

Conversely, if yd < vd, the deviation becomes a negative value, and the above peak value I is passed through the control compensation circuit Gv(S)'e.
, ft decreased and finally If! Let l<0. Therefore,
The active power P also becomes a negative value, and this time the energy Ps
Is t a DC cogen? It is regenerated from Cd to the power supply. As a result, the DC voltage Vd decreases and is finally controlled to vd=vd*.

The load device L″oAD is, for example, a known PWM inverter-driven induction motor, etc., and supplies -1) of electric power to a DC capacitor Cd, which is a DC voltage source.
When the EAD consumes power, the DC voltage vd decreases, but according to the above control, the active power P is supplied from the power supply and is always controlled to ■d#vd*. Conversely, the load device l I;
When power regeneration is performed from AD (when the motor is operated regeneratively), Vd rises once, but the effective power P, which is generated in the power supply SUP, is regenerated by that amount.
Vd#yd*. That is, the load device L″oAD
The power P supplied from the power source SUP is automatically adjusted according to power consumption or power regeneration.

At this time, the input current! , is in phase or out of phase with the power supply voltage (
Since it is controlled by the sine wave of (during regeneration), the input power factor = 1
Therefore, the harmonic components have extremely small values.

[The problem that the invention aims to solve] The conventional power conversion device described above has the following problems.

That is, the active power P shown in equation (2) is supplied from the single-phase AC power supply SUP.

is the stationary component p. =x V, II m/2 and fluctuation ΔP, e V, #I, -(2)2ωt/2 are included. By this variation jPa, the DC smoothing capacitor cd
The voltage vd applied to changes. The variation ΔVd is approximately expressed by the following equation.

4(alL; d'Vd0 Remember, vdo is the average value of the DC voltage Vd. This DC voltage fluctuation ΔVd increases in proportion to the capacity of the converter, so in order to suppress it, DC smoothing is applied. need to be increased.

When the DC voltage Vd fluctuates, the current supplied to the load device fluctuates, resulting in various adverse effects.

For example, in a load device that drives an induction vibrator using an automatic inverter, the current supplied to the motor changes due to fluctuations in the DC voltage vd, and there is a difference between the output frequency of the inverter and the frequency corresponding to the fluctuation in the DC voltage. This causes a beat phenomenon and causes torque pulsation, etc.

Therefore, in order to reduce the DC voltage q fluctuation, a large capacity smoothing capacitor Cdl must be prepared, which increases the weight and dimension of the device, leading to an increase in cost.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems, and it suppresses fluctuations in the DC voltage Vd without increasing the capacity of the smoothing capacitor Cd, thereby reducing the size and weight of the device.)
An object of the present invention is to provide a power conversion device that can be expected to reduce costs.

[Means for Solving the Problems] In order to achieve the above objects, the present invention provides a single-phase AC power supply, a pulse width modulation control converter connected to the AC power supply via an AC reactor, and a pulse width modulation control converter connected to the AC power supply via an AC reactor. A smoothing capacitor connected to the DC side of the width modulation control converter, a resonant circuit connected in parallel to the smoothing capacitor and having a resonance point near twice the frequency of the AC power supply, and a resonant circuit connected to the DC side of the width modulation control converter, It is equipped with a load device that serves as a source.

[Action Co-pulse width modulation control converter controls the current supplied from the single-phase AC power supply so that the voltage applied to the smoothing capacitor is approximately constant.] Since this input current is controlled to be a sine wave in phase with the power supply voltage, operation with an input power factor of 1 and few harmonics is achieved.

The resonant circuit is connected in parallel with the smoothing capacitor, and its resonance point is adjusted to twice the power supply frequency.

Therefore, fluctuations in single-phase power are absorbed by this resonant circuit, making it possible to suppress fluctuations in DC voltage without increasing the capacitance of the smoothing capacitor.

As a result of reducing the capacitance of the DC smoothing capacitor, the energy storage capacity of the DC circuit is reduced, and the effect of a sudden change in load becomes greater. Therefore, we improved the response to sudden load changes by introducing so-called Tweed soft word control, which detects the active power consumed by the load and proactively supplements the current supplied from the AC power supply according to the detected value. It is possible to compensate for the drawbacks caused by reducing the capacitance of the smoothing capacitor.

As a result, the power conversion device of the present invention can significantly reduce the capacitance of the smoothing capacitor and provide a system with less fluctuation in DC voltage.

[Example] FIG. 1 shows an embodiment of the power conversion device of the present invention.

FIG.

In the diagram, SUP is a single-phase AC power supply, L is a current transformer reactor, and C
ON'v is a pulse width modulation control converter, cd is a DC smoothing capacitor, Ry e Ly e Cy is a resonant circuit resistor, reactor, and capacitor, and LOAD is a load device.

The converter C0NV includes elements with self-extinguishing capability (e.g. f-) turn-off iris resistor, etc.) S, ~S4, freewheeling diodes D, ~D, and a DC reactor L,
It is composed of IL2.

Further, as a control circuit, current detectors CT, CTL, comparator c4. c2, adder A, ,A2. Multiplier ML, voltage control compensation circuit ay(s), current control compensation circuit G, (S)
, a feed forward control calculator Fp, and a pulse width modulation control circuit PWM are provided.

The voltage Vd of the DC smoothing capacitor Cd is detected via an insulating amplifier or the like, and compared with the command value Vd rate by the comparator C1. The deviation g, = Vd” -Vd is input to the next voltage control compensation circuit Gv(S).GY(8)
Normally, an integral element is used, and control is performed so that the steady-state component of the deviation j7 becomes zero. G, output Δ of (3)
Im is input to the adder A, and is added to the output "mo" of the Tweed word control calculator FF, which will be described later, to obtain the input current!
, becomes the peak value command.

The current detector CTL is a DC voltage source (smoothing capacitor Cd
) to the current I, J supplied to the load device LOAD.By multiplying the DC voltage Vd''Ik by the current I, J supplied to the load device LOAD, the active power PLWv. Then, the following calculation is performed by the feed 7? word control calculator FF.

I-1・PL ・・・・・・・・・(4
)mov- Here, vrn is the peak value of the power supply voltage V.

The output signal I = Xmo + ΔXm of the adder A is input to the multiplier ML, and multiplied by ωt within a unit sine wave synchronized with the power supply voltage V.

Output 1 of multiplier ML. *=-・龜ωt is the input current 1. supplied from the power supply SUP. This is the command value for

The comparator C2 receives an input current 1. detected by the current detector CT. The above command value 1g is input, and its deviation C□=rB*-1 is calculated. The deviation gx is input to the next current control compensation circuit GX(S) and proportionally amplified. Note that if an inverting proportional amplifier is used for C and (S), and its proportionality constant is n, then G and (S) = -K.

becomes.

The power supply voltage vs acts as a disturbance on the input current control system. Therefore, a voltage to cancel this is generated from the converter, and the compensation *VS* is inputted to the PWM control circuit via the adder A2. Therefore, the control input signal e1 for pulse width modulation (PWM) control is expressed as follows.

ei = "t"'t+vs"""-(
5) Norse width modulation control is a well-known method, in which the carrier wave signal (
(triangular wave signal) and the control input signal e1f: are compared, and a dirt signal of the self-extinguishing ability S, to S4 forming the converter is generated.

FIG. 2 shows a time chart for explaining the operation of the notarus width modulation control.

In FIG. 2, X, Yti carrier wave signal, eiL control input signal, g are elements S1. s2 dirt signal 1r2Fi
The dirt signal (■) of the elements S5eS4 indicates the voltage generated on the AC side of the converter.

Carrier waves X and Y are two triangular waves with a phase difference of 180°,
By comparing
make.

That is, when e1≧X, g and w are “1” and the element S.

is on, S2 is off, and when el<X, g, = go
At s, element S2 is turned on, and element S is turned off. Also, e1≧Y
When g2=11'', the element S is on and S3 is off, and when e<Y, the element S is on and S4 is off when g2==#0''.

The voltage vc generated on the AC side of the converter is S, and when 84 is on (when s2 and S are off) vc=+v.

Conversely, when 82 and S are on (when S and 84 are off), vc=-V. In other modes (e.g. S, and S are on or S2 and SA are on), the VC-
It becomes O.

As can be seen from Fig. 2, the elements S, ~S, turn on and off at the carrier frequency, but the voltage generated by the converter, vcFi,
Controlled at a frequency twice the carrier frequency. The average value of vc (indicated by a broken line) is a value proportional to the control input signal e1.

Returning to FIG. 1, each control operation will be explained. First, input current control will be explained.

When I, > I, the deviation 8X becomes a positive value.
Decrease l. Then, the voltage vc generated by the converter decreases, and the voltage vLll applied to the AC reactor L8
T'``8''C increases, so that the input current I.

increase.

On the contrary, 1. <I, the deviation -0 becomes a negative value, and el t- is increased. Therefore, VC decreases, and input current 2 increases. If the command value is changed in a sinusoidal manner, the input current Is will be controlled in a sinusoidal manner accordingly.

Next, the operation of DC critical condition control will be explained.

When vd>vd, the deviation becomes a positive value and the peak value command Irn is increased. That is, the input current (2) is increased and supplied from the power supply SUP. Active power p8=v
, ·I, is increased. As a result, the smooth core f7Cd
Kit energy p, -t = (IA) cd・v, 2
is accumulated, increasing the DC voltage V.

Conversely, when V<V, the deviation does not take a negative value, and the peak value command E is decreased and further made into a negative value. When I becomes a negative value, the energy stored in the smoothing capacitor C4 is regenerated to the power supply SUP, and the DC voltage V,
decreases.

As a result, it is controlled so that Vd=V.

As mentioned above, the DC voltage V is controlled to match its command value vd*, and if Vd* ==constant, the DC voltage vd should also be constant, but in the case of a single-phase power supply, , As mentioned before, since a power change wJt- is essentially involved, the corresponding voltage variation ΔV cannot be removed even by control.

FIG. 3 shows the resonant circuit of the present invention (Ry*Ly*C
y) is a time chart diagram for explaining the operation.

In the figure, V indicates the power supply voltage, V indicates the input current, PIL indicates the active power, and RI indicates the waveform of the current flowing through the resonant circuit.

The input current I is controlled to be a sine wave in phase with the power supply voltage vs. As a result, the effective power P8 is P6=v,・min.

=vmIlth1ωt・Work mΦoutωt ■ Bow=-1-2 (1-House2ωt) =P,. +ΔP, ・・・・・・(6)
become that way. This variation ΔP8 in the active power Ps appears as a variation in the DC output current 4d of the converter C0NV. Assuming that the fluctuation of DC voltage vd is small, v#v
If we consider that, the fluctuation d of the DC current 1d
d.

The minute Δ4d is expressed as follows.

Therefore, the resonant circuit shown in Fig. 1 (R + Ly * Cy
) is selected as shown in the following equation, it is possible to bypass the variation Δi of the DC current A to the resonant circuit. However, the resistance R2 is ignored as it is small.

2ωL, =-knee ・・・・・・・・・(8)
2ωC1 In other words, the resonant frequency of this resonant circuit is 2 ωC1 of the power supply frequency.
The impedance at that frequency is 2. The resistance is only 82 minutes.

The resistor R2 is intended to stabilize (accelerate attenuation) against disturbances, etc., and may have a very small value. Therefore, all of the variation Δ of the DC current shown by equation (7) flows through this resonant circuit, and the resonant circuit current 1. Beam=Δ1. becomes. The magnitude of the difference is proportional to the value of the active power P supplied from the power source.

As a result, Smooth Co/Den? The power source, , flowing into C, has a load current of 1. In this case, the following formula is obtained.

A = (a-i, -riap = 4d0 + Δ(, -4, -ri#1d0-port) ・Curved surface (9) Steadyly becomes ci, . = shi, and satisfies 'cap = o, and the smoothing capacitor cd The voltage vd of is almost constant.

As described above, in the device of the present invention, the power fluctuations of the single-phase power source can be absorbed by the resonant circuit, and the capacitance of the DC smoothing capacitor cd can be significantly reduced compared to the conventional device.

However, if the smoothing capacitor C4 is made smaller, a drawback arises in that the energy storage capacity in the DC circuit also becomes smaller. Therefore, when a sudden load change occurs, if the response of the DC voltage control is slow, the DC voltage vd will suddenly drop or rise sharply. (2) If V suddenly decreases, it becomes impossible to generate a voltage opposite to the power supply voltage V, resulting in an uncontrollable situation. Also, v
If d increases rapidly, an overvoltage will occur, leading to destruction of the element.

Therefore, the feeder t-word control described below is effective as a control method for the apparatus of the present invention.

In FIG. 1, FF indicates a feedforward control calculation circuit.

First, the active power PL consumed by the load device LOAD is detected. In a DC circuit, the product of the DC current 1L and the DC voltage V is the active power P. By inputting this to the feed 7t word control calculation circuit FF' and calculating the following equation, the peak value command l of the input current is obtained. Find e.

■ ■-・PL ・・・・・・・・・()0″
no v,.

When the load suddenly changes, the output signal Δ! from the DC voltage control circuit Gv(S). The wave height command ■lln#X0° is immediately given without waiting for □. Therefore, active power P1 is supplied from the power source as shown in the following equation.

Ps=v,・Eng.

=v 1 blood ωt-I - inner ωt m mO ゝ”' (1w2ωt) =PL(1-possible 2ωt) ・・・・・・・・・(
b) Since the variation in P is absorbed by the above-mentioned resonant circuit, Pl. = PL and active power P consumed by the load
L can be supplied immediately from the power supply without increasing or decreasing the energy stored in the DC circuit.

Therefore, smooth conde/? The voltage vd of C4 can always be maintained at a constant value, and the drawback of reducing the capacitance of C6 can be eliminated.

4 to 6 show the simulation results obtained by a computer, where vd is the DC voltage, 1. is the input current, vc
represents the voltage generated on the alternating current side of the converter, ■ represents the power supply voltage, and A represents each waveform of the current flowing through the resonant circuit.

As a condition for Simil-Si1, the command value of DC voltage vd*
= 1900V, power supply frequency fB-60Hz, carrier frequency 420Hz, and at t-12.5 msec, the load PL is suddenly changed from OkW to 75 kW.

FIG. 4 shows the results of a conventional device with a smoothing capacitor Cd=7,500 μF inserted.

The fluctuation in the DC voltage V is ΔVd(,,) #187V.

Figure 5 shows the results of the shimmy range of the conventional device.
cd=2. sooμF. Fluctuation in DC voltage V ΔVa (pp) # Increases to 530 V.

Figure 6 shows the results of the shimmy operation of the device of the present invention. Even though it is as small as C, = 1,500 μF, all the power fluctuations of the single-phase power supply are absorbed by the resonant circuit, and the DC voltage vd remains almost constant. Only PW
Although pulsation associated with M control remains, it is possible to remove this as well. In response to sudden load changes, the aforementioned feed 7 word control works effectively, and fluctuations in vd are kept small.

[Effects of the Invention] As described above, the power converter of the present invention is an AC/DC converter that can maintain the input power factor at 1 and has few harmonic components of the input current, and is suitable for single-phase power supply. By absorbing power fluctuations in the DC side resonant circuit, the capacitance of the smoothing capacitor C6 can be reduced and fluctuations in the DC voltage can be suppressed. It is possible to achieve a quick response through feedforward control even when the load suddenly changes. The disadvantage of reducing the capacity of C can be removed. Therefore, it is possible to provide a power converter that is ideal from both the power source side and the load side, as well as to reduce the size, weight, and cost of the entire device.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the power conversion device of the present invention,
Figure 2 is a time chart for explaining the control operation in Figure 1, Figure 3 is a time chart for explaining the operation in Figure 1, and Figures 4 and 5 are for the conventional device. FIG. 6 is a diagram showing the results of computer simulation, FIG. 6 is a diagram showing the simulation results of the device of the present invention, and FIG. 7 is a configuration diagram of a conventional power conversion device. SUP...Single-phase AC power supply, L8...AC reactor, C0NU...Riguru width modulation control converter, C6...
・・DC smoothing capacitor, RF + Lr r CF・
・・Resonant circuit resistance, reactor capacitor, LoA
D... Load device, S, ~S,... Self-extinguishing element, D
, ~D, . . . diode, Ll, L2 . . . DC reactor, CT8. CTL...Current detector, C1, C
2... Comparator, A1. A2... Adder, ML...
・Multiplier, GY(S)...voltage control compensation circuit, aK
(S)...Current control compensation circuit, FF...Feed 7
t-word control calculation circuit, PWM...pulse width control circuit.

Claims (3)

[Claims] (1) A single-phase AC power supply, a pulse width modulation control converter connected to the AC power supply via an AC reactor, a smoothing capacitor connected to the DC side of the pulse width modulation control converter, and a parallel to the smoothing capacitor. A power conversion device comprising: a resonant circuit having a resonance point near twice the frequency of the AC power supply connected to the AC power source; and a load device using the smoothing capacitor as a voltage source. (2) The power conversion device according to claim 1, wherein the resonant circuit is constituted by a series circuit of a resistor, a reactor, and a capacitor. (3) A single-phase AC power supply, a pulse width modulation control converter connected to the AC power supply via an AC reactor, a smoothing capacitor connected to the DC side of this pulse width modulation control converter, and parallel to the smoothing capacitor. The active power supplied to the load device of a power converter device includes a resonant circuit connected to the AC power source and having a resonance point near twice the frequency of the AC power supply, and a load device using the smoothing capacitor as a voltage source. A method for controlling a power conversion device, comprising detecting the detected value, calculating a command value of a current to be supplied from the AC power supply based on the detected value, and controlling the current supplied from the AC power supply by the pulse width modulation control converter. .