JPS6046773A - Power converter - Google Patents

Abstract

PURPOSE:To control to allow a power source current to follow its command value faithfully by constructing to eliminate the influence of the disturbance of the power source voltage inputted to a power source current control system. CONSTITUTION:When an actual current Ic has a relationship of Ic*>Ic to the output current command value Ic* of a converter, a deviation epsilon1=Ic*-Ic becomes positive value, thereby increasing one ei of the input signal of a pulse width modulation control through a control compensator G1(S). Thus, the output current Ic of the converter is increased, and the current Ic is controlled to bring into coincidence with the value Ic*. On the contrary, when becoming Ic*< Ic, the current Ic decreases, and is controlled be bring into coincidence with the value Ic*. In this case, the voltage VL applied to an AC reactor Ls relates only to the deviation epsilon1=Ic*-Ic, and is not affected by the influence of the current voltage Vs.

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a power conversion device consisting of a DC voltage source supplied with power from AC electrolytic erosion and its load device. [Technical Background of the Invention] A load device using a DC voltage source as a power source Examples of f+'-' include a pulse width modulation control (PWM) inverter + induction motor, or a DC chopper device or ten-sided current.If a battery is used as the pressure source, There is no problem with switching, but I am worried about the AC/DC power converter (
In recent years, when obtaining DC voltage via a converter, reactive power and harmonic waves generated on the commercial power source side have become a problem. In order to solve this problem, a method (such as 171886, 1986) was proposed in which a pulse width modulation control (PWM) converter was inserted into the rhJ between the open power supply and the DC voltage source (capacitor) as a C1 power converter. has been done. FIG. 1 shows a #f diagram of a conventional power converter using a PWM converter as an AC/DC power converter. In the figure, SUP is a single-phase AC power supply, L8 is an AC reactor, CONV is an AC/DC power converter, Cd is a DC smoothing capacitor, and LδAD is a load device. Converter C0NV is a cable with self-extinguishing capability (for example, a gate turn-off thyristor) 81-84. Wheeling diode DI-D4 and DC reactor "l+L"
2, and the element s1-84 receives the AC side voltage Vc.
In order to control the value of , a known pulse width modulation control is performed. In other words, the converter C0NV becomes a pulse width modulation control (PWM) inverter when viewed from the 1-volt current (capacitor) CD, and in that case, the AC power supply SUP
The side can be seen as a kind of load. This conventional power converter has the above-mentioned DC voltage source CCt'I
If, the pressure Va becomes almost constant 6 (Uni) It controls the current IB supplied from the AC power supply, ■ It is capable of four-quadrant operation according to the power demand from the Senri device LδAD. ■ The above input The current generator 8 is always controlled to be in phase with the voltage v8 of the electric current υ9, so that the input power factor is 1. ■ The main feature is that the input current I11 is controlled in a sinusoidal manner, so the harmonics are extremely small. The control operation of this device will be briefly explained below.
j@circuit and 1. The following are available: CTo is an AC current detector s, R1+RZ is a voltage dividing resistor for detecting DC voltage, ISO is an isolation amplifier, VR
is a DC voltage setting device, C1 to C3 are comparators, Gv(S
) is a voltage control compensation circuit, ML is a multiplier, OA is an inverting operational amplifier, GI(S) is a current control compensation circuit, '1'
RG is a carrier wave (triangular wave) generator, and OC is a gate control circuit. First, the DC voltage V detected via the isolation amplifier I80
a and the voltage command value ■d* from the voltage setting device VR are input to the comparator C1, and the deviation εv-vd-Va is calculated. The deviation ε■ is input to the control compensation circuit Gv(S). It is integrally amplified or proportionally amplified and becomes the peak value command ■m of the input current generator 8. Furthermore, the nuclear wave red value command ■m is inputted by two multipliers MLl, and the multiplier is combined with the other input sinωt. The input signal ωt is a unit sine wave synchronized with the power supply voltage ``β''''Vm-sin ωt, and is obtained by detecting the power supply voltage 6 and multiplying it by a constant (1/■m times). The output signal ■t of the multiplier 31 unit ML gives the command value of 'i(f, current) to be supplied from the power supply, and is expressed by the quintic equation. LB -Im , 5Lllωt ----------- ---(
1) The input current command value 1B* is inverted by the inverting amplifier OA, and becomes the command value IC* of the AC current Ic supplied from the converter C0NV to the power supply SUP.
c* is called the converter output current command value. The converter output current IC is detected by a 22-current current detector CTOr2 and inputted to a comparator C2r2. Comparator C2
According to the above command value. ' and the detected value Ic are compared,
Deviation εknee■C*=■. I get criticized. In addition, the deviation 6IVi
Next control compensation circuit (J) (S) C input is proportional.
θ width and control input signal e for pulse width modulation control
It becomes 1. Pulse width modulation control is a known method, using carrier wave generator 'L'.
This control is performed by RG, comparator C3, and gate control circuit GC-2. That is, the carrier wave generator TR() has a frequency of 1 kHz
A comparator C8 generates a triangular wave eT of @j degrees, and compares the triangular wave eT with the input signal e1, and calculates the deviation εT''
An on/off signal is given from the gate control circuit ()C to the gate turn-off thyristor sl-s4 in accordance with ei eT. ei) When el, that is, when the deviation ε is positive, the thyristors 81 and 84 are turned on (at this time, s+2.S3
is off) The AC output voltage VC of the converter becomes +Va when 0 el (eg, that is, when the deviation ε1 is negative), the thyristors S2 and 88 are turned on (at this time, when the deviation ε1 is negative,
+84 is off), Vc==-Vd. Moreover, if ei is a positive value, the on-cut surfaces of S1 and 84 will be lit, and the on-buttons of S2 and 83 will be shortened, and the average value of % Vc will be as follows: e, proportional to /
It becomes a positive value at ζ voltage. When 201 is a negative value, the on-periods of 82 and 83 are longer than the on-periods of 81 and 84, and the average value of the converter output voltage vc is a value proportional to the input voltage. Therefore, it becomes a negative value. In other words, the output voltage Vc of the converter is controlled to a value proportional to the input signal ei. The output current of the converter 1. The inverted value of 1B) is controlled by adjusting the output voltage ■0 of the converter.The AC reactor LB has a differential voltage vL = v, - between the power supply voltage vS and the output voltage ■c of the converter. v. is applied. When Va > Va, the power supply current Is increases in the direction of the arrow in the figure. In other words, the converter output current 1c acts to decrease in the direction of the arrow in the figure. 2. VP
(When VC, the converter output current IaIj works to add j'- in the direction of the arrow in the diagram. For the converter output current command value Ic, the actual current ■
When c is in the relationship IC*>IC, deviation εI=Ic*
Icl becomes a positive value and increases the PWM control input 1i e1 via the control compensation circuit Gr(S). Therefore, the converter output voltage VC also increases in proportion to the input signal e1, VC>V, and the converter output current Ic increases in the direction of the arrow in the figure. In the case of reverse f Ni IC < engineering C,
The deviation εl becomes a negative value, which decreases el, that is, Vc, so that Vo<V, and the output current 1G is decreased. Therefore, the output current IcPj of the converter is controlled to match its command value IO*. If the command value ■c* is changed in a sinusoidal manner, the actual current I (, , is also controlled in a sinusoidal manner).
The command value of the converter output current, which is the inverted value of c
* is the inverted value of the flow command value 8* directed to the input from the power supply. Therefore, the input current 1B is often controlled to follow the command value ls*. Next, the control operation of the voltage Vd of the DC capacitor Cd will be explained. A comparator CI compares the detected DC voltage value Vd and its command value ■d*. When Va">Vd, the deviation εV becomes a positive value and increases the input current peak value m via the control compensation circuit Gv(S). If the input current command value 18*, then Equation (1) As shown in , it is powered by a sine wave that is in phase with the power supply voltage.Therefore, the actual input current 8 is as described above (, IB =
If it is controlled by I8*, when the above peak value ■m is a positive value, the active power 1゛6 shown by the following formula is single 1]
From the power supply SUP, F! via the converter C0NV! 1'
, r'At, capacitor C (l is suspected. P8 = V6x I. = Vm・Eng.・(sinωt)2 : vm・1m・(1−cos 2ωt)/2 −−−−
----(2) (I: Then, the energy PB-t is accumulated as a direct function capacitor cdI knee 2-Cdvd2, and as a result, the DC voltage Va increases. Conversely, ■d*<Vd In this case, the deviation εV becomes a negative value, and the above-mentioned wave height value m is reduced through the full compensation circuit Gv(8), and finally Im < 0. Therefore, the effective 1゛ and the force P8 are also negative values. This time, energy P81 is regenerated from mI current capacitor cd by electric i<+20.As a result, DC voltage Vd decreases and finally V
d = vd*. An example of the load device L2iAD is a known PWM inverter-driven i1iυ conduction motor, which exchanges power with a DC capacitor Cd, which is a DC voltage source. Load device: If LciAD consumes power, DC voltage V
Although a decreases, the above control c2 supplies active power Pa from the power source and is always controlled to vd 4 v6*. Conversely, when power is regenerated from the load device ICIAD (when the rust conduction motor is operated regeneratively), Vd increases once, but the effective 111. By regenerating the force P, then t) Va' = Va*. That is, the power P8 supplied from the power source SUP is automatically adjusted according to the power consumption or power regeneration of the load device LδAD. At this time, the input current IB is controlled to be a sine wave that is in phase with the electric power, power source, and pressure, or inverse i1j (during regeneration), so naturally, with an input force of 4''l, the high-power wave component becomes an extremely small value. [Problems with the prior art] Such conventional power converters have the following five problems.In other words, in the conventional power converters, the DC voltage Va applied to the smoothing capacitor is approximately PWM' the values of the electric current θir and Is supplied from the AC power supply so that
2 y Hearth f2 controls 91, but is this the case? I? , because the disturbance due to the electric pressure formation enters the flow control system 1, the input current 1. There is a disadvantage that it becomes impossible to accurately control the IJ, and it becomes impossible to control the input current with few harmonic components when the input power factor = 1. Figure 2 shows a circuit diagram of the power supply side of the device shown in Figure 1. In the figure, L, R, are the inductance of the AC reactor.
The converter output voltage and tie (Q represent 1, 1 and 1 of the Q flow. From now on, the voltage equation can be expressed as C1 as shown below./Here, p is a similar expression. va vo=(Rs+LB-p)-i8-------
-(31) Therefore, the block diagram of the power supply current (input current) control system is as shown in Figure 3. In Figure 3, GI(S) is the transfer function of the current control circuit, and Kce-"' is The transfer function of the PW 1 converter is
KO represents a constant of proportionality, and τ represents dead time. Furthermore, S
is the Laplace operator. In the control system shown in Figure 3, m? The l'j- current controller 8 is intended to be controlled by following its command value controller 8*, but since a disturbance due to the power supply voltage vB comes in, the
It doesn't melt. For this reason, the power supply current command is L! As shown in the equation Is*J page J), it is given by a sine wave IG flow synchronized with the power supply voltage va, but the current flowing in the actual division is ah and the size is equal to the above command value t. It will be different. Therefore, the initial target was the input power rate = 1. There is a problem that reduction of the active word wave content cannot be achieved. [Z6 Akira's Eye/J] The present invention was made in view of the above problems, and it eliminates the influence of power supply voltage disturbance entering the power supply current (input current) control system. Set the upper control current 18 to its command value ■8
to follow closely

[2] The purpose is to provide a controlled power conversion device. [Summary of the Invention] In order to achieve the above object, the present invention provides a pulse width modulation control converter capable of regenerative operation connected to an AC power supply via an AC reactor, and a DC output side of the pulse width modulation control converter. C2 connected to the load device 'voltage t
A smoothing capacitor is connected to the smoothing capacitor, and the DC voltage is controlled to a value corresponding to the reference voltage (1) by detecting the DC voltage of the smoothing capacitor.
: a voltage control circuit and an input current control circuit that controls the current supplied from the acid source in accordance with the output signal l1 of the DC voltage control circuit; and a compensation signal that detects the voltage of the AC power supply. an input current itt control system, comprising: a disturbance compensation circuit that outputs the input current control circuit; 16; This is a power conversion device in which the influence of source voltage disturbance is eliminated so that the current supplied from the alternating current faithfully follows the command (1fi i2). The figure is a diagram showing the embodiment of the th power converter device of the present invention. In the figure, 8Ul) is the low-phase AC 11ft inverter, La is the current reactor, C0NV is the pulse width variable 1yJ control controller, cd is a DC smoothing capacitor, and LoAD is a load device. The pulse width modulation control converter CoNV is an element (such as a gate turn-or-thyristor) that has self-extinguishing capability.
l-s4. It is composed of a wheeling diode DI-D4 and a DC reactor]・l+"2. As a control circuit, a transformer PT that detects the power supply voltage is used as a control circuit.
, current transformer CTc for alternating current detection, voltage dividing resistor R1+R2s isolation amplifier 180 for direct current voltage detection, planar voltage setting device 1. Comparator cl-08, voltage control fit]41
(S), disturbance compensation circuit I (Q, addition SAD. Carrier wave generator TRG and gate control circuit OC are prepared. Power supply voltage ■6 is detected by transformer FT, CI/Vm by operational amplifier OAI) By multiplying, a local sinusoidal wave S ωt synchronized with the frost source voltage can be obtained. Further, a DC voltage d is detected via the voltage dividing resistor RL R2 and the isolation amplifier ISO. The detected DC voltage value Va and the voltage command value ■d from the 1σ current voltage setter VR are input to the comparator cl, and the deviation εy=Va*−Va is calculated. The deviation εV is input to the next voltage control compensation circuit 0v (S), where it is proportionally amplified or integrally amplified to obtain the peak value ■m of the input terminal command value 8*.
becomes. The multiplier ML multiplies the unit sine wave Slnωt by the wave height value m to create a command value Is" = lm-5inωt of the input current I6 supplied from the power supply. Note that the input terminal command value I- can be inverted by the inversion calculation yII and width switch OA2, and the AC side output current IO of the converter (inverted value of the input current I) becomes the command value I.*.The current transformer CTc is the output current of the converter 7. The detection value IC is input to the comparator C2 together with the command value IC*.The comparator C2 detects the deviation ε
I. ′−■. is set to X, and the next current control compensation circuit 0r (
S) is amplified by the ratio vi+. Note that the output e1 of the current control compensation circuit GI(S) becomes one of the input signals for pulse width modulation control. On the other hand, the unit sine wave sinωt, which is the output signal of the amplifier OAI, is also input to the disturbance compensation circuit HQ Im, and is multiplied by a constant to provide the correction value e8. The compensation value e8
0 becomes the other input signal for pulse width modulation control. That is, adder AD adds output signal e1 of 0I(S) and output signal es of disturbance compensation circuit HO to obtain input signal e1 for pulse width modulation control. =81+68 is obtained. The carrier wave generator TRG generates a triangular wave eT having a frequency of about lkl-1z, and provides a carrier wave signal for pulse width modulation control. The input signal e;
An on/off signal is given to S4. A known method is used for pulse width variation control, and input signal e
A voltage Vc proportional to ; is output from converter C0NV. In other words, the ratio? ! +4 When the number of threads is KO and the dead time due to pulse width modulation control is τ■. = KO
−exp (−rs) ・e; −−−−−−−−(
There is a relationship between 41S nila plus operators. Output box of converter: Current Ic (inverted value of input 'd' input signal 6 supplied from the power supply) is connected to the 0 AC reactor L8 which is controlled by fA W of the output voltage 0 of the above converter 7 (-) The difference between the power supply 'dT, voltage) rs and the output voltage of the converter 'tl is the voltage VL =: Vs V
When c is applied and OVL is positive, the source current IB increases in the direction of the arrow in the figure.
The output IQc flow Ic decreases in the direction of the arrow in the figure.
: Work. When VL is negative in the waveform, the convergence output ``r'' works to increase in the direction of the arrow in the diagram. times) -4-, and the pulse variation is 1
1 control input signal C1 is given by the following equation. e8-(■m/Kc)・sinωt ---------
-1(5+■m2'city571accepted pressure wave peak value ho: Because of the proportionality constant of the converter, the converter output voltage Vcrj, from equation (4), becomes as follows.■.= KC-exp (-τS)・el : KC-e
xp (-τS)・(e□→c,)=K,(,-ex
p (-rs) ・e1+ exp (-t8)
・Vm−slnωt −−−−−−−(6) That is,
If we assume that the dead time τ associated with pulse width modulation control is sufficiently small, then ■. = Kc−e□+v6−−−−−−−−−−−−(
The relationship 7) holds, and the voltage VL applied to the actuator LBl that flows is vL = v, -vo = -t<. , el, -----
----1--(It becomes 81, and when controlling the input current I8, it is no longer affected by the power supply voltage ■8. The output current command value of the converter IC*1m, whereas the current IC is I.* > When the relation number of Ic = certain, the deviation ε
G = I(B*Ic becomes a positive value, and the control compensation circuit Gx(
8) of the input signal of pulse width modulation control via 1'''') e
Let's add some elbows. Therefore, the AC 1 noactor voltage Vbid shown by equation (8) is applied in the opposite direction to the arrow in the diagram, and the converter output current 1. Increase in the direction of the evil arrow. Therefore, the constraint is increased so that the actual tonne current 1c is equal to the command value IC''-2. If ■c*〈■c is given to jf, ■L becomes a positive value, and the actual Current 1 decreases.In other words, the actual current IC is controlled to match its command value Ic*.In this case, the voltage applied to the dam reactor LB multiplied by the voltage vL, and the individual difference ε■−IO *-i, only related to 箪W tolerant pressure V,
It is not affected by any other factors. Converter output? l]; Stream 1c is '6 preserve input'
Reversal of current 18! The command value Ic* of the converter output frost current, which is −1, is the inverse value of the command value IB* of the input current from the power supply. Therefore, the converter's output current ■c follows its command value IC and is controlled by jli, which means that the input current IB from the converter follows its command value IC.
It will be controlled by following s*-2. The old current voltage Va of the smoothing capacitor cd is its command value yd*
-2 If the above input current command value 1s* is given as a sine wave current synchronized with the power supply voltage 8 so that they match, the sinusoidal control will follow the actual divided input current Ia4sorl. . [Effects of the Invention] As described above, according to the power conversion device of the present invention, the input current I supplied from the meter is not affected by the power supply voltage VB by its command value 11! *Following the *, it is possible to faithfully control f2, flat? If the above input current command value ■t is given as a sine wave current synchronized with the voltage VB so that the 114 current voltage Va of the capacitor CD matches its command value ■d*, the real pupil The input current generator 8 also follows the command 8*, and the phase shift and amplitude error are controlled to be small. Therefore, the intended purpose of keeping the input power factor of the sfW power converter at 10 and reducing the harmonic content of the input current is achieved. In addition, input current control A11. If i+ is no longer affected by the source voltage disturbance, the design of the control compensation circuit GI(S) for the current 7t71J system becomes easier, which also has the advantage of making it easier to stabilize the control system and improve response. . Although the embodiments of the present invention describe a single-phase power source, it is possible that the same applies to a three-phase power source or other multi-phase power source.

[Brief explanation of drawings]

Figure 1 is a diagram of a conventional power zone 4ψ device, Figure 2 is a circuit diagram of the power supply side of the device in Figure 1, and Figure 3 is a block diagram of the current control system of the device in Figure 1. The diagram and FIG. 4 are four-character diagrams showing an example of the actual application of the power conversion device of the present invention. Reactor CδNV...Pulse width variable 8 control converter cd...-1m+ current smoothing capacitor LδAD...Load device f'181-s4...Gate turn-off thyristor D1-D4...Wheeling diode LL+L
2...DC reactor FT...Transformer CT,...
Current transformer 1<1. R2...Voltage dividing resistor ISO...Isolation amplifier ■R...DC voltage setting device CI-c8...
Comparator Gv(S)... Voltage open side 1 sleeve detection circuit ML...
1st power booster OAl, OA2... operational amplifier G engineering (
S)...'#ri, flow control bucket circuit AD...adder HO...disturbance supplementary circuit TI(0...carrier wave generator GC...gate control circuit

Claims (1)

[Claims] Through an AC reactor [, -C AC power supply (2 connected regenerative 11 pulse width modulation control converter capable of side operation, 1
A smoothing capacitor is connected to the DC output side of the pulse width modulation control converter described in j11 and serves as a voltage source for the load device, and the DC voltage of the af smoothing capacitor is detected at fJ and controlled to a value according to the reference voltage. and an input current ff1l that controls the current supplied from the AC whistle 1 source in accordance with the output signal of the DC th:pressure control circuit.
l i needle circuit, said alternating current '..., disturbance detector circuit which detects the inkstone' voltage and outputs the signal 1tt4=, and output signal f2 of said input current sub-side circuit 1; said compensation (fi); 'direct force variable 4 sudden smoke W' characterized by comprising an adder circuit which obtains the control (manpower) of the pulse width variable a+++J jIIJ control converter (by human power) (,,S-%3) by adding the symbol.