JPS6046775A - Controlling method of power converter - Google Patents

Abstract

PURPOSE:To eliminate the variation in the DC voltage by calculating the specified value of a current to be supplied from an AC power source based on the current value supplied to a load unit, and controlling a pulse width modulation control converter, thereby improving the response of a DC voltage control system. CONSTITUTION:A converter CONV has self-extinguishing capacity elements S1-S4, wheeling diodes D1-D4 and DC reactors L1, L2. A controller has a current detecting current transformer CT0, current voltage detecting voltage detecting voltage dividing resistors R1, R2, an insulating amplifier ISO, a DC voltage setter VR, comparators C1, C2, C3, a voltage control compensator Gv, and adder AD, multipliers MLo, MLs, an operational amplifier Km, an inverting operational amplifier OA, a current control compensator G1, a carrier generator TRG, and a gate controller GC, the specified value of the current to be supplied from an AC power source SUP is calculated on the basis of the current supplied to the load unit LOAD, thereby controlling the converter CONV.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for controlling a power conversion device that includes a DC voltage source that receives power from an AC power source and its load device.

[Technical Background of the Invention] A load device whose power source is a DC voltage source; There is a pulse-width modulation control (PWM) inverter + a motor, a motor, or a device with DC current knowledge, a motor, etc. 0 If you use a battery as this DC voltage source, there is not much of a problem in 1. In recent years, when a clear voltage is obtained from a commercial power supply through an AC/DC power converter, reactive power, power, and harmonics generated on the commercial power supply side have become a problem.

In order to solve this problem, a method was proposed in which a pulse width modulation control (PWM) converter was inserted as a force transducer between the bending electric field and the voltage source (capacitor).
! 1. 171886, etc.) was proposed.

FIG. 1 shows a configuration diagram of a conventional power conversion device using a pwm converter as an AC/DC power converter.

In the figure, t, SUP is a single-phase AC power supply, IJ+] is an AC reactor, C0NV is an AC/DC power converter,
cd is a DC smoothing capacitor s TJ o A I) is a load device. The converter C0NV is an element with self-extinguishing capability (for example, a gate turn-off switch) Sl-
84, consisting of a wheeling diode DI-D4 and DC reactors Ll, L, and the above elements s1-s
, a well-known pulse width modulation control is performed in order to control the value of the intercurrent side voltage Vo. Converter C
0NV is a DC voltage source (capacitor) If it is from Ca, it becomes a pulse width modulation control (PWM) inverter, and in that case, the AC power supply SUP side can be seen as a kind of load.

This conventional power conversion device controls the current 8 supplied from the AC 3-current power source so that the voltage Vd of the DC voltage rlikCd becomes almost constant. Must be capable of 4-quadrant operation.

(2) The input current 18 is controlled to be in phase with the electrolytic erosion voltage VB, and the input power factor is 1.

■ Because the input current L & J is controlled in the form of a sine wave,
Harmonics become extremely small.

can be opened as a feature.

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

A primary control circuit is prepared.

CTc is an alternating current detector, R1, R2 are voltage dividing resistors for detecting the current voltage, 180 volt isolation amplifier, VR is a voltage setting device, cl, ~C8 are comparators s Ov (S
) is a voltage control compensation circuit, ML is a multiplier, OA is an inverting operational amplifier, GI(S)'dX & control M (i l path,
TRGiJ# transmitting wave (triangular wave) generator, GC is a gate control circuit.

First, f7. ij
, I current 'r11, HVd and the voltage command value Vd* from the voltage setting device VR force are input to the comparator C1, and the deviation ε■-vd*
-■ Add d.

The deviation εV is input to the open side 1 supplementary bale circuit 0V (S), and is integrally amplified or proportionally amplified to become the peak value command m of the input current 6.

The relevant wave height command■. is input to the multiplier ML, i'1, and the other input sin ωt is combined. The input signal 5ifi GJ t is the voltage Vs = Vm s
It can be determined by detecting the power supply voltage (1)8 with a unit sine wave synchronized with inωt and multiplying it by a constant (1,/Vm times).

It gives a command value of the current to be supplied from the output signal IBI''i of the multiplier ML, and is expressed by the following equation.

Is −Im °slnωt, ------1----
(The input current command value ■s* is inverted by the inverting amplifier OA, and becomes the command value ■c* of the AC current ■c supplied from the converter C0NV to the multiplexer SUP.Hereinafter, here, T
c" is called the converter output current command value.

Converter output current Ic is detected by alternating current detector CTc and input to comparator C2. The above command value is calculated by comparator C2. ' and detected value I. are compared, O1l difference ε■-I. *-■. is painted. The deviation ε, ij is input to the next control circuit member circuit GI(S)11. The proportional amplification results in a control input signal e1 for pulse width modulation control.

Pulse 11! The fi modulation fti control is a known method, and includes a carrier generator '1'RG, a comparator C8, and a gate control circuit G.
4nl is performed by C.

That is, the carrier wave generator TRG generates a triangular wave eT with a frequency of about 1 kHz, the comparator C3 collects the triangular wave eT and the input signal e1, and according to the deviation εT::e1-eT, from the gate control circuit GC, On/off signals are given to gate turn-off thyristors 81-84.

el) When eT is 5, that is, when the deviation εT is positive, thyristor Sl and 84 are turned on (at this time, 82.
s, 3d off) converter AC output voltage Vc Id
When the deviation el<eT becomes +Va, that is, when the deviation εT is negative,
Thyristors S2 and 88 are turned on (at this time, 81, 8
+ IrJ'off), vc--vd and No.ru.

Moreover, when Hel is a positive rice, the dog is cut off by 1 in the on Jtli If ball 1 of S1 and 84, the on period of S2 and 88 becomes scorching, and the average I+7 of ■o is proportional to the input signal e1. This 1 has a pressure of 11-. Conversely, when el is a negative value, the on-periods of 82 and 88 are longer than the on-periods of SJ and 84, and the converter output voltage Vot
The /, + average value is a value proportional to the input signal e1 and is a monthly value.

That is, the output voltage ■c of the converter is controlled to a value proportional to the input signal e□.

The output current Ic of the converter (TtM, the inverted value of the input current I8 supplied from the source) is equal to the output voltage V of the converter. It is controlled by adjusting.

9: Current reactor L, voltage difference between the voltage of the power supply (■8) and the output voltage of the converter (■c) == v, -
v.

is applied.

■When 8〉vc, 1 (I source current JR increases in the direction of the arrow in the figure. When reversed, the flow Ic to the converter output cuff acts to decrease in the direction of the arrow in the figure. Conversely, Vs <
When Vo, the converter output phase 5-flow IC works to increase in the direction of the lk+ arrow.

When there is a relationship of converter output current command (actual current ic is IO* with respect to ijlc*) I, the deviation εI-■
c*-IO takes a positive value and increases the PWM jolt control input signal e1 via the control compensation circuit Gl(S). Therefore, converter output voltage ■0 also increases in proportion to input signal e□, resulting in VO)VB, converter output frost; Increase in the direction of the arrow in the figure. On the other hand, if ■c*〈Ic, it becomes a candy of 1 difference εI minus el, that is, V
Decrease C. Therefore, the output 14L flow lO of the converter is controlled so as to match its command value Jc*. If the command value IO* is changed in a sinusoidal manner, the back mold and the flow Io are also controlled in a sinusoidal manner following it.

The converter's output current Ic is the input current from the source ■
The command value ■c* of the converter output current is the inverse value of the command value ■6* of the input current from the source. Therefore, the input current I6 is controlled to follow the command value ■6*.

Next, the control operation of the voltage d of the DC capacitor Ca will be explained.

The comparator C1 compares the detected DC pressure value vd and its command value ■d*. When Vd*>vd, the deviation ε■d becomes a positive value, and the input current wave I white value ■m is increased via the control compensation circuit C)v(S). The input current command value 16* is expressed by equation (1)1. As shown above, a sine wave in phase with the galvanic voltage is given. Therefore, the actual input current 1B is Ai + as mentioned above,
If I, , == IB* is controlled, when the above wave height value 1m is a positive value, the effective power P shown by the following formula
8 is supplied from a single-phase power supply SUP to a Te bending capacitor cd via a converter CδNv'. (Margin below) p8
=V, xIs = V@-1,@ ・(311Q)t)"=Vm
・ITG (1cos 2ωt)/2 --------
(2) Therefore, the energy 13B, t flows through f' and is transferred to the capacitor Cd as LCdVd2, and as a result, the DC voltage Vd increases.

Conversely, if ■d*<Vd, the deviation εV becomes a negative value, and the above peak value 1 m is applied via the control compensation circuit Gv(S, ).
Finally, Im < 0. Therefore, Fudot
43. Force P8 also becomes a negative value, and now Fi, energy P
, t are regenerated from the DC capacitor Cd to the power supply.

As a result, the meandering voltage Vd decreases and finally Vd :=
It is controlled by Vd*.

゛ The load device LEAD is, for example, a known PWM inverter-driven induction motor or the like, and exchanges power with the DC capacitor Ca, which is a meandering voltage source.

If the load device LδAD consumes power, the dual-current voltage Va decreases, but due to the upper control, the active power P8 from the city 5 source is reduced.
On the other hand, when power is regenerated from the load device LEAD (when a rust conduction motor is operated regeneratively), vd is temporarily increased, but the power supply is By regenerating the active power P8 to the SUP, vd〒Vd'' is also obtained. In other words, the negative walking device LδAl)
According to the power consumption or power regeneration, the power P6 supplied from the power source 5TJP is arranged around eight times along its own axis.

At this time, the input terminal I is controlled to a sine wave in the same phase or opposite phase (during regeneration) to the 7 voltage of the power supply box, so the input power factor -
1, the high circular wave component has an extremely small value.

[Problems with speed-driven, 1/1 technique] Such conventional power conversion devices have the following problems.

In other words, it is desirable that the direct current voltage and capacitor voltage, which are the DC voltage of the load device, be kept constant at the set voltage value regardless of the magnitude of the load current or the power running, but this is not possible with conventional devices. Since the so-called feedback control method is adopted for the direct current voltage control, the control response is delayed and the direct current voltage fluctuates sharply in response to sudden load changes.

Lf A, if4 flow gun pressure command value d*, actual voltage, detected value V
In order to make the steady-state component of the deviation εy = Vd*-V6 of d zero, the integral V violet is often used in the next voltage control compensation circuit.If <1, a faster response could not be expected.

Due to the above-mentioned control delay, if the DC voltage fluctuated significantly, the withstand voltage of the device had to be increased by that fluctuation, resulting in an uneconomical system. In addition to affecting the control operation of the iiM control converter, accurate current control was no longer possible, causing waveform distortion of the input current.Furthermore, when viewed from the load side, the DC voltage source described above is a large output impedance converter. , Zeng was considered to be a power source with a particularly small vertical load.

[Object of the Invention] The present invention has been made in view of the above problems, and provides a power conversion device that improves the response of the DC voltage control system and eliminates fluctuations in DC voltage due to sudden changes in load current. The purpose is to provide a control method for

[Summary of the Invention] The present invention comprises an 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, In a power conversion device comprising a load device using this smoothing capacitor as a voltage source, a current supplied to the load device is detected, and a command value of the current to be supplied from the AC power source is calculated based on the detected value. , is a control method for a power conversion device in which the response of a DC voltage control system is improved by controlling the current supplied from the AC power source by the pulse width modulation control converter.

[Embodiment of the Invention] FIG. 2 is a configuration diagram showing an embodiment of the power conversion device of the present invention.

In the diagram, SUP is a single-phase AC power supply, LB is an AC reactor,
C3NV is a pulse width modulation control converter, Ca capacitor is a DC smoothing capacitor, and LoAD is a load device.

The converter CciNV includes an element with self-extinguishing capability (for example, a Gate Kuhn Oscilk) Sl-84, a wheeling diode Di-D4, and a DC reactor L1.
It is separated from L2.

As a control circuit, a current transformer CT for current detection is used.

CTo, blood flow voltage detection voltage dividing resistor JIR2% isolation amplifier l5O5 DC voltage setter VR1 comparator C], +C2
HO2, output, pressure control complementary a circuit (lv(S), adder AD1 multiplier Mho, ML,, operation (9-1 so 1f
31 device T<-m 1 inversion 'a R)? / Medium 1i 'l'i 0A 1° 11°C flow III circuit compensation circuit 0 (S), carrier wave generator TRG, and gate 1/control circuit QC are prepared.

The frost of the DC smoothing capacitor Cd, the voltage Vd, is the voltage dividing resistor i<
1. R2 and isolation amplifier 180, one is input to comparator CI, and the other is input to one-to-one multiplier ML0.

The comparator c1 compares the voltage command value ■d* from the DC frost 5-pressure setting device VR with the above-mentioned 1 white current minimum pressure detection value Vd, and calculates the deviation εv−■d*−■d. The deviation εV is input to the next voltage control compensation circuit Gy(S). Gy(S)
Normally, an integral element is used, and control is performed slowly so that the steady-state component of the deviation εV becomes zero. The output d(l- of (]lv(S)) is input to the adder AI (12), and is added to the operation (q) described later: the output of the amplifier I (2).
becomes the wave height command.

1F, the current detector CTo is a DC voltage source (smoothing capacitor C
a) to the load device LδAD -a i],
It detects flow JO, and its detection value is for
・It is manually operated by 0.

The load π1. The product of the flow detection value ■o and the flow chamber, pressure detection value Vd is calculated, and the countercurrent, frost force Po-v, . . .■o supplied to the fJ load is calculated. This 1'7-1 style training power P. is preposition: j! ! width tool K
m is inputted and multiplied by a constant (2/Vm times) 11 to obtain the above-mentioned peak value command Im.

Here, Vm is the peak value of the city pressure.

The output signals ink4-d of the multipliers A and D are input to another multiplier ML. The output of MLs t=(Im+d)・S stone ωt is the command value of the input current supplied from the power supply SUP, and its inverted value I〇--IIl* is the AC output current of converter Ci; NV. The command value is xc (=-18).The inverting performance amplifier OA is an inverting bar with a magnification of 1.

The ratio rfI device C2 receives the converter output current ■c detected by @'f%i current detector CTc and the above command value ■c.
* is input 1+, and its deviation ε■-Ic*-■c is calculated.

The deviation ε■ is input to the next frost control compensation circuit 0x(S), where it is proportionally amplified and becomes the control input r1 ei for pulse width modulation control.

The pulse width variation 6P1 control is a known method, and the carrier wave generator T
This control is performed by RG, comparator C8, and gate control circuit GC.

That is, the carrier wave generator TRG generates a triangular wave (3T) with a frequency of about 1 kHz, and the comparator C8 generates the triangular wave e.
The input signal e1 is compared with the input signal e1, and the deviation ε〒-e knee eT is determined by the gate control circuit GC.

When el>eT, that is, when the deviation 6T is positive, the thyristors 81 and 84 are turned on (at this time, S2 and S8 are turned off), and the AC5fE side output voltage of the converter C0NV is as follows:
It becomes Vd. When t, e < eT, that is, the deviation ε
When T is negative, Ki1. Zyrista S2 and 88 are on, (
At this time, Sl and 84 are off) s Va ='-Vd.

Moreover, if %el is a positive value and the dog is turned off, the above S1 and 8
The on-period of S2 and 88 becomes longer, and becomes a positive voltage region proportional to the average value of vo, 11/I, and the value of e0. Conversely, %el becomes negative. Noi i
When i1, Sl and 84q) From the on period, S2 and 8
8 is longer, and the average value of the output voltage vc of the converter is a value proportional to the input signal e, which is a square candy.

That is, the converter output γ(1, pressure 2o) is controlled to a value proportional to the input signal e1.

Converter output current Ic (■ il- supplied from 6 sources
The inverted value of the input current (6) is controlled by adjusting the output voltage Vo of the converter.

The AC reactor L8 receives the power supply voltage Vθ and the output voltage V of the converter. Differential voltage vL = vB-v.

is applied.

When V, > V, the power supply current Is increases in the direction of the arrow in the figure. In other words, the converter output current IO acts to decrease in the direction of the arrow in section l. On the contrary, Vs
< When Va, the converter output type 1st stream ■C works to increase in the direction of the arrow in the figure.

Actual current 1. for converter output current command value IO*.
When is in the relationship IC*>IC, the deviation εT−IO*−
10 becomes a positive i1α, which increases the PWM control input signal e1 via the control compensation circuit (4I(S). Therefore,
The converter output voltage VC also increases in proportion to the input signal e, and Vo>V, so the converter output sum and current 1c
Increase by 1 yen in the direction of the arrow. On the contrary, ■. *〈Ic
In this case, the deviation ε becomes a negative value, and el, that is, V
c is decreased so that Vc < Vs, and the output current IC is decreased. This results in the output of the converter 'tit flow I.

It is controlled to match the mouth command value 101'. If the command value lo* is changed in a sinusoidal manner, the actual current IC will follow it and be controlled in a sinusoidal manner.The output current Ic of the converter is the input current IB from the power supply.
is the inverted value of , and is the command value 1 of the output current of the sweet converter.
o This is the inverted value of the command value 18* of the input current from the power source. Therefore, the input current IsU is controlled to follow the command value I69.

Next, the control operation of the rectangular voltage Va of the DC capacitor Cd of the device of the present invention will be explained.

By multiplying multiplier MLO, current voltage ■d and load ■・δ
AD to A' (take the product of the surface number current Io that is t)
``d, Io −−−−−−−−−−−+81.

This load ■・F'l-ru effective 1 and 5 to be steered to ciAD
It is power.

Next, this active power Po is input to the ignition amplifier I (m, and the fly high value command 1m of the flow IL3 is set at the input '[41] supplied from the power source SUI).

Engineering. −(j full P. −−−−−−−−−−−−
...-d is the applied force, but first we will explain this correction by assuming that hd is zero.

The wave height command m and the frost,
The unit sine wave peak ωt synchronized with the source voltage Vs' = Vm-sinωt is combined, and the input current command value - is I.
s −Irn 1 sin ωt −−−−−−−−−(
Get 51. The actual input current IB follows this command value knee and is a sine wave (controlled by two) in phase with the power supply voltage 8. Therefore, the active power P supplied from the AC power supply SUP.

can be expressed as the following equation.

P, == VB, I.

=■m・Work m・(s+nrat)z ” Vm4m(1cos2ωt)/2 −−−−−−−
(6) This active power P11 changes at an angular frequency twice the angular frequency ω of the AC power supply SUP, and its average value PB
Hato becomes. That is, assuming that there is no circuit loss, the active power Po supplied to the load LEAD is equal to the average value of the active power P8 supplied from the power source SUP, and the energy of energy to the double-current smoothing capacitor, S Cd, is equal to the average value of the active power P8 supplied from the power source SUP. It can be considered that there is almost no input or output. However, in the case of single-phase power, as mentioned above, the active power I'l! Since the voltage fluctuates at a frequency twice the power source frequency, it is assumed that a clear current capacitor C6 having a capacity capable of smoothing out the fluctuation is provided.

Therefore, the active power PO required for the loads LCiA and D is directly supplied as AC power P from the AC power supply SUP. L, DC capacitor cd can be used even for sudden load fluctuations.
The paper pressure Va h is maintained at a substantially constant value without any fluctuation.

However, in actual circuits, there is always circuit loss, and some kind of active power correction is required.

The correction lad input to the adder AD is for correcting the Nt't4 effective power, which is achieved by performing DC voltage control using conventional feedback control. In other words, the comparator itself determines the 1h flow turtle pressure command value ■d* and the DC voltage detection value V.
d is compared and the deviation εV-vd*-Va is used to determine the correction amount d via the control compensation circuit Gv(8). Designed to exhibit slow control response.

When there is a circuit loss, the energy of the DC capacitor Ca gradually decreases due to the loss, and the DC voltage ■d decreases. When Vd*〉Vd, 141'4 M
iv = Vd*-Vdtri IE(D, value becomes, control compensation circuit 5) Increase correction -5f d via path 0V(S). Therefore, input current command value L+*= (Irn + d), s! nωt --
−−1−−−−L8) wave height ■m′=1m+d increases, and the average value P8 of the active power supplied from the exchange city and Ryo SUP is increased so that Va=■d*. to control.

Therefore, ■d* (if it becomes Vd), the deviation εV becomes a negative value, decreases the correction amount d, lowers the average value Ps of the active power supplied from the AC power supply sUP, and finally Vd= ■d
It is controlled so that *.

This voltage control is performed very slowly and does not respond to sudden changes in load.

According to the present invention, the force conversion device is slightly different from the current value of the electric current.
The wave height/lower command of the input voltage t to be supplied is 1 ml: Y: Therefore, the input current 1B is controlled, and the DC box 1 pressure error due to circuit 11 loss etc. is slow, and the pressure control system It is corrected by configuring.

In addition, in the embodiment shown in FIG. 2, ! '1. Although the explanation has been made for the old AC/old AC full power supply, it is needless to say that it can be similarly applied to three-phase or polyphase AC I#, and electric power.

￥P 9 load device LδAl) as a chopper device + (■ flow i1 as 1 (tan or pulse width variable, 1jjt, j control inverter + induction 4. electric motor etc. is considered) 7. Ru.

Furthermore, in the embodiment of FIG. 2, the effective power P supplied to the load j1. [7, Actual measurement value of DC Fit pressure v]
Based on the considerations of d, DC current, and current IO, the relevant surface number wound 2 pressure Va
PO; Vd·To may be set on the premise that 11 matches the command value vd*.

In addition, load equipment F4. If LδAD is a pulse 1/4 physical condition control inverter + AC room, motive, etc., calculate the remedial power PO that is being supplied to the AC 9 load, and input M from that value.
You can also set the wave height of the L flow.

[Effects of the Invention] As described above, according to the control method of the power conversion device of the present invention, the input "rL" to be supplied from one whistle source in response to sudden load changes
'H; The peak value command for flow I8 is immediately given.

DC military Va based on control delay, which was a problem in the past.
It has become possible to minimize fluctuations in As a result, various adverse effects caused by the DC voltage converter 1j11 (problems such as increased converter capacity, input current waveform distortion or transient damage, and decreased load carrying capacity) are eliminated.
It is possible to provide a power conversion device that is extremely economical and has high reliability.

Note that input power rate = 1. The fact that the input current has a low harmonic content is -h15'! Not even P.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional power converter f' conversion j1, and FIG. 2 is a block diagram showing an embodiment of the power conversion device of the present invention. SUP...AC ML source L8...AC reactor C
0NV...H/' Space width variable A control converter cd.
...DC smoothing capacitor LOAD...Valve loading device'S
l-S4...Kate turn off the lister DI-D
4. Wheeling diodes Ll, L2...DC reactor

Claims (1)

[Claims] An 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 load device using the smoothing capacitor as a voltage imitator. A power conversion device comprising: a control converter that detects the current supplied to the load device, calculates a command value of the current to be supplied from the AC power source based on the detected value, and changes the pulse width; Therefore, a method for controlling a power converter device, characterized in that the current supplied from the AC power supply is controlled.