KR100266403B1 - Output voltage control device for 3-phase inverter - Google Patents

Abstract

The present invention relates to an output voltage control device for a three-phase inverter, which detects the three-phase voltage of the first, second, and third filter capacitors of the three-phase power supply device and outputs U, V, and W phase DC detection voltages. U, V, W phase DC detector; A U, V, W phase voltage comparator for comparing the U, V, W phase DC detection voltages of the U, V, W phase DC detectors with predetermined reference voltages to obtain an error; First, third, and fifth proportional integral controllers for performing proportional integral control on the error of the U, V, and W phase voltage comparators; A U, V, W phase multiplier for multiplying the output of the first, third, and fifth proportional integral controllers by multiplying phase information to obtain a U, V, W phase reference current; A U, V, W phase current comparator for comparing the U, V, W phase reference currents obtained by the U, V, W phase multipliers with actual U, V, W phase currents respectively detected at the output side of the inverter; Second, fourth, and sixth proportional integral controllers for performing proportional integral control on the outputs of the U, V, and W phase current comparisons; A gate for generating a drive signal based on the outputs of the second, fourth, and sixth proportional integral controllers and inputting the same to the inverter to control the three-phase output voltage of the inverter by turning on / off the switching element of the inverter. It is composed of a driving unit, so that it is possible to precisely control the three-phase output voltage of the inverter even under non-linear load or unbalanced load.

Description

Output voltage control device of three-phase inverter

1 is a configuration diagram of an output voltage control device of a conventional three-phase inverter.

2 is a block diagram of an output voltage control device of the three-phase inverter of the present invention.

3 is an internal configuration diagram of the U-phase DC detector of FIG.

* Explanation of symbols for main parts of the drawings

17,23,29: U, V, W phase DC detector 18,24,30: U, V, W phase voltage comparator

19,25,31: 1st, 3rd, 5th proportional integral controller

20,26,32: U, V, W phase multipliers 21,27,33: U, V, W phase current comparators

22,28,34: 2nd, 4th, 6th proportional integral controller

35: gate driver 36: inverter

50: load C1, C2, C3: first, second, third filter capacitor

The present invention relates to an output voltage control device for a three-phase inverter that can produce a three-phase output voltage of a high-quality inverter, in particular, by precisely controlling the three-phase output voltage of the inverter even when the load of the inverter is a nonlinear load or an unbalanced load The present invention relates to an output voltage control device of a three-phase inverter for producing a good three-phase output voltage.

1 shows a block diagram of an output voltage control apparatus of a conventional three-phase inverter.

The three-phase power supply device is configured such that the first, second, third filter capacitors C1, C2, C3, and the like are connected to the output side of the inverter 16 including the switching elements. Reference numeral 50 denotes a load of the inverter 16.

In particular, the first filter capacitor C1 is connected between the U phase current (iu) output line and the V phase current (iv) output line of the inverter 16, and the second filter capacitor C2 is the V phase current (iv). ) Is connected between the output line and the W phase current (iw) output line, and the third filter capacitor C3 is connected in parallel to the first filter capacitor C1 and the second filter capacitor C2.

The output voltage control device of the conventional three-phase inverter for turning on / off the switching element of the inverter 16 to control the three-phase output voltage (filter capacitor voltage) of the inverter 16, as shown in FIG. As shown, the three-phase voltages Vcu, Vcv, and Vcw of the first, second, and third filter capacitors C1, C2, and C3 are converted into two-phase voltages (two-phase voltages on a fixed coordinate axis). Converts the first two-phase voltage limiter 1 to be converted and the two-phase voltage of the first three-phase and two-phase converter 1 into two-phase voltages V _df and V _qf on the rotational coordinate axis. By comparing the two-phase voltage (V _df , V _qf ) of the first fixed shaft / rotary shaft converter (2) and the first fixed shaft / rotary shaft converter (2) to a predetermined reference voltage (V _dref , V _qref ) Proportional integral control is performed on the errors of the first and second comparators 3 and 4 for obtaining the error and the first and second comparators 3 and 4, so that a predetermined reference current i _dref and i _qref Proportional Integral Controller 7 for First and Second Voltages 8) and a second three-phase / two-phase converter 5 for converting three-phase currents i _u , i _v , i _w of the inverter 16 into two-phase currents (currents on a fixed coordinate axis) and outputting them. A second fixed shaft / rotation shaft converter 6 for converting the two-phase current output by the second three-phase / two-phase converter 5 into two-phase _currents i _df and i _qf on the rotary coordinate axis and outputting the same; The reference current i _dref generated by the proportional integral controllers 7 and 8 for the first and second voltages is output to the two-phase currents i _df and i _qf output by the second fixed shaft / rotation axis converter 6. , i _qref ) and the third and fourth comparators 9 and 10 for obtaining the error, and the first and the proportional integral control for the error obtained by the third and fourth comparators 9 and 10. A rotary shaft / fixed shaft converter 13 for converting the outputs of the second current proportional integral controllers 11 and 12 and the outputs of the first and second current proportional integral controllers 11 and 12 back to the values of the fixed coordinate axes. ) And this rotary shaft / fixed shaft converter (13) A two-phase / three-phase converter 14 for converting the value of the signal into a three-phase value, and a drive signal (gate signal) is generated based on the output of the two-phase / three-phase converter 14 and the inverter 16 And a gate driver 15 which inputs to and turns on / off the switching element of the inverter 16.

The operation will be described below.

'Vcu' of the three-phase power supply device of FIG. 1 is the voltage across the first filter capacitor C1, 'Vcv' is the voltage across the second filter capacitor C2, and 'Vcw' is the third filter capacitor ( It is the voltage across C3).

First, these three-phase voltages Vcu, Vcv, Vcw are input to the first three-phase / two-phase converter 1 of the output voltage control device of the conventional three-phase inverter.

The first three-phase / two-phase converter 1 converts the three-phase voltages Vcu, Vcv, and Vcw into two-phase voltages, and inputs them to the first fixed shaft / rotation axis converter 2. The first fixed shaft / rotation axis converter 2 converts the two-phase voltage (voltage on the fixed coordinate axis) into two-phase voltage (direct current value) V _df , V _qf on the rotational coordinate axis, and outputs it. At this time, the two-phase voltage (V _df , V _qf ) on the rotational coordinate axis has a phase coinciding with the phase of the power supply voltage and has a constant value.

From the first fixed axis / rotational axis converter (2) the two-phase voltages (V _df, V _qf) output from Hansang voltage (V _df) is input to the first comparator (3), and the other phase voltages (V _qf ) Is input to the second comparator 4. The first comparator 3 compares the received phase voltage V _df with a predetermined reference voltage V _{dref, which} is an input of the other side, and _{obtains an} error thereof. The proportional integral controller 7 for the first voltage of the next stage is obtained. ). Similarly, the second comparator 4 compares the input phase voltage V _qf with a predetermined reference voltage V _{qref, which} is an input of the other side, and _{obtains an} error thereof. Enter in (8).

The proportional integral controllers 7 and 8 for the first and second voltages perform proportional integral control on each of the input errors, and the two reference currents i _dref and i _qref which are the respective result values of the proportional integral control. Is input to the third and fourth comparators 9 and 10.

Similarly, the three-phase current i _u , i _v , i _w of the inverter 16 also undergoes substantially the same processing as the three-phase voltages Vcu, Vcv, and Vcw.

That is, the three-phase current i _u , i _v , i _w is converted into a two-phase current in the second three-phase / two-phase converter 5, and then the rotational coordinate axis in the second fixed-axis / rotation axis converter 6. The output is converted to a constant two-phase current (i _df ) (i _qf ) of the phase.

The third comparator 9 compares this phase current i _df with the reference current i _{dref previously} inputted from the proportional integral controller 7 for the first voltage, and _{obtains an} error thereof, and the fourth comparator 10 _Calculates the error by comparing the phase current i _qf with the reference current i _{qref previously} input from the proportional integral controller 8 for the second voltage.

The proportional integral controllers 11 and 12 for the third and fourth currents perform proportional integral control on the errors output from the third and fourth comparators 9 and 10, respectively, and the rotation shaft / fixed shaft converter 13 Converts the outputs of the third and fourth current proportional integral controllers 11 and 12 back into the values of the fixed coordinate axes and inputs them to the two-phase and three-phase converters 14.

The two-phase / three-phase converter 14 converts the value of the rotation axis / fixed-axis converter 13 into a three-phase value, and the gate driver 15 based on the output of the two-phase / three-phase converter 14. Thus, a gate signal serving as a drive signal is obtained and inputted to the inverter 16 to turn on / off the switching element of the inverter 16.

Accordingly, the three-phase voltages Vcu, Vcv, and Vcw of the first, second, and third filter capacitors C1, C2, and C3 according to the gate signal are generated. As a result, the first and second comparators 1 are generated. By controlling the error output in (2) to be zero, the desired three-phase voltages Vcu, Vcv, and Vcw are obtained.

The above has been described when the load of the three-phase power supply device is a linear load. In other words, as the load is a linear load, the value converted by the two converters, that is, the three-phase / two-phase converter and the fixed-axis / rotary axis converter, was a constant DC value as mentioned above.

However, in the above conventional configuration, when the load is a nonlinear load, the converted value is not a direct current value but a pulsation value in which an AC component is added to the direct current.

The same is true when the load is unequal. As a result, the three-phase output voltage cannot be precisely controlled.

As described above, conventionally, when the load is a nonlinear load or an unbalanced load, the value converted by the two transducers appears as a pulsation value. In the prior art, the error due to this pulsation component cannot be completely compensated. Three-phase output voltage cannot be controlled precisely. Therefore, there is a problem that a good three-phase output voltage is not made.

The present invention provides an output voltage control device for a three-phase inverter that can precisely control the three-phase output voltage of the inverter even when the load of the inverter is a nonlinear load or an unbalanced load, so that a high-quality three-phase output voltage can be produced. Purpose in providing.

The output voltage control device of the three-phase inverter of the present invention according to the above object, as shown in Figure 2, the first, second, third filter capacitor (C1) (C2) (C3) of the three-phase power supply device U, V, W phase DC detectors 17, 23, 29 for detecting three-phase voltages Vcu (Vcv) (Vcw) and outputting U, V, W phase DC detection voltages; A U, V, W phase voltage comparator for calculating an error by comparing the U, V, W phase DC detection voltages of the U, V, W phase DC detectors 17, 23, 29 with a predetermined reference voltage (18). 24, 30; First, third, and fifth proportional integral controllers (19, 25, 31) for performing proportional integral control on the errors of the U, V, and W phase voltage comparators (18, 24, 30); A U, V, W phase multiplier (20) that calculates the U, V, W phase reference current by multiplying the output phase information of the first, third, and fifth proportional integral controllers (19, 25, 31). (26) (32); The U, V, and W phase currents obtained by the U, V, and W phase multipliers 20, 26, and 32 are actually U, V, and W phase currents (iu) (iv) detected at the output side of the inverter 36. (iw) and U, V, W phase current comparators (21) (27) and (33), respectively; Second, fourth and sixth proportional integral controllers 22, 28 and 34 which perform proportional integral control on the outputs of the U, V and W phase current comparators 21, 27 and 33; A driving signal is generated based on the outputs of the second and fourth sixth proportional integral controllers 22, 28 and 34, and is inputted to the inverter 36 to turn on the switching element of the inverter 36. The gate driver 35 is configured to control the three-phase output voltage of the inverter 36 by turning on / off.

The operation will be described below.

The first filter capacitor C1 is connected between the U phase current (iu) output line and the V phase current (iv) output line of the inverter 36, and the second filter capacitor C2 is the V phase current (iv) output line. And a third filter capacitor C3 are connected in parallel to the first filter capacitor C1 and the second filter capacitor C2.

Components of the inverter power supply other than the inverter 36 and the first, second, and third filter capacitors C1, C2, and C3 are not important for understanding and implementing the present invention. The part is not described anymore.

When U, V, W phase voltages (Vcu) (Vcv) (Vcw) are output from the first, second, and third filter capacitors C1, C2, and C3 of the three-phase power supply device, U, V, The W phase DC detectors 17, 23 and 29 detect the U, V, and W phase voltages (Vcu) (Vcv) (Vcw) and respectively detect the U, V, and W phase DC detection voltages (V _{cu_f} ) (V). _{cv_f} ) (V _{cw_f} )

3 shows the internal configuration of the U-phase DC detector 17. As shown therein, the U-phase DC detector 17 includes a first multiplier 17-1 that multiplies the received U-phase voltage Vcu by the first phase information Sin θ, and a predetermined reference voltage V _ref. ) Is multiplied by the second phase information (Cos ² θ), the second multiplier 17-2, the output of the second multiplier 17-2 and the output of the first multiplier 17-1 are added to the U phase The adder 17-3 calculates the DC detection voltage V _{cu_f} .

This configuration expresses the U phase DC detection voltage V _{cu_f} output from the U phase DC detector 17 as follows.

V _{cu_f} = Vcu Sin θ + V _ref Cos ² θ ----------- (1)

The configuration of the V, W phase DC detectors 23 and 29 is the same as that of the above U phase DC detector 17 except for the fact that the phase information input to the two multipliers is different. The first and second phase information in the V-phase DC detector 23 are Sin (θ-3π / 2) and Cos ² (θ-3π / 2), and the first and second phase information in the W phase DC detector 23 are as follows. The two phase information is Sin (θ + 3π / 2) and Cos ² (θ + 3π / 2).

The result of the V, W-phase direct-current detection voltage (V _{cv_f) (cw_f} V) output from the above-described configuration V, W-phase direct current detector 23, 29, the expression as follows.

V _{cv_f} = Vcu Sin (θ-3π / 2) + V _ref Cos ² (θ-3π / 2) -------- (2)

V _{cw_f} = Vcw Sin (θ + 3π / 2) + V _ref Cos ² (θ + 3π / 2) --------- (3)

The U, V, and W phase voltages Vcu (Vcv) (Vcw) of the first, second, and third filter capacitors C1, C2, and C3 are as follows.

Vcu = V _m Sin θ --------- (4)

Vcv = V _m Sin (θ-3π / 2) --------- (5)

Vcw = V _m Sin (θ + 3π / 2) --------- (6)

Substituting these three equations (4) (5) (6) into the above three equations (1) (2) (3) and arranging them, U, V, W phase DC detection voltage (V _{cu_f} ) (V _{cv_f} (V _{cw_f} ) is finally expressed as follows.

V _{cu_f} = V _m Sin ² θ + V _ref Cos ² θ --------- (7)

V _{cv_f} = V _m Sin ² (θ-3π / 2) + V _ref Cos ² (θ-3π / 2) --------- (8)

V _{cw_f} = V _m Sin ² (θ + 3π / 2) + V _ref Cos ² (θ + 3π / 2) --------- (9)

In this case, assuming that V _m and V _ref are approximately equal, since Sin ² X + Cos ² X = 1, the U-phase DC detection voltage Vcu_f is expressed as a DC value with phase information θ removed. do.

The same applies to the V and W phase DC detection voltages V _{cv_f} and V _{cw_f} .

As described above, the U, V, and W phase DC detectors 17, 23, and 29 are three-phase voltages V _cu and V V of the first, second, and third filter capacitors C1, C2, and C3. _cv ) (V _cw ) to obtain U, V, W phase DC detection voltage (V _{cu_f} ) (V _{cv_f} ) (V _{cw_f} ), from which phase information has been removed, and U, V, W phase voltage comparators (18) (24) ( In 30).

The U, V, and W phase voltage comparators 18, 24, and 30 respectively input the input U, V, and W phase DC detection voltages (V _{cu_f} ) (V _{cv_f} ) (V _{cw_f} ) to predetermined reference voltages (V). _ref ) to obtain an error and input it to the first, third, and fifth proportional integral controllers 19, 25, 31.

The first, third, and fifth proportional integral controllers 19, 25, and 31 perform proportional integral control with respect to the error, and the U, V, and W multipliers 20, 26, and 32 are present. The multiplication operation by multiplying the outputs of the first, third, and fifth proportional integral controllers 19, 25, 31 by the corresponding phase information (SiN θ) (θ-3π / 2) (θ + 3π / 2) The U, V, and W phase reference currents (i _{u_ref} ) (i _{v_ref} ) (i _{w_ref} ) are obtained and output.

The U, V, W phase current comparators 21, 27, 33 are U, V, W phase reference currents (i _{u_ref} ) (output from the U, V, W phase multipliers 20, 26, 32) ( i _{v_ref} ) (i _{w_ref} ) is _compared with the actual U, V, and W phase _currents iu (iv) (iw) detected at the output side of the inverter 36, respectively.

The second, fourth, and sixth proportional integral controllers 22, 28, and 34 perform proportional integral control on the outputs of the U, V, and W phase current comparators 21, 27, and 33, and the gate driver ( 35 generates a drive signal, that is, a gate signal, based on the outputs of the second, fourth, and sixth proportional integral controllers 22, 28, and 34, and inputs the same to the inverter 36. The three-phase output voltage of the inverter 36 is controlled by turning on / off the switching element of (36).

As described in detail above, in the present invention, since the inverter is independently controlled in the form of voltage control of the single-phase inverter, the inverter can precisely control the three-phase output voltage of the inverter even when the load of the inverter is unbalanced or nonlinear. This has the effect of obtaining a phase output voltage.

Claims (2)

An output voltage control device for a three-phase inverter for controlling a three-phase output voltage of a three-phase power supply device including an inverter and first, second, and third filter capacitors, wherein the first and second of the three-phase power supply device. A U, V, W phase DC detector for detecting the three-phase voltage of the third filter capacitor and outputting U, V, W phase DC detection voltages; A U, V, W phase voltage comparator for comparing the U, V, W phase DC detection voltages of the U, V, W phase DC detectors with predetermined reference voltages to obtain an error; First, third, and fifth proportional integral controllers for performing proportional integral control on the error of the U, V, and W phase voltage comparators; A U, V, W phase multiplier for multiplying the output of the first, third, and fifth proportional integral controllers by multiplying phase information to obtain a U, V, W phase reference current; A U, V, W phase current comparator for comparing the U, V, W phase reference currents obtained by the U, V, W phase multipliers with actual U, V, W phase currents detected at the output side of the inverter; Second, fourth, and sixth proportional integral controllers for performing proportional integral control on the outputs of the U, V, and W phase current comparisons; A gate for generating a drive signal based on the outputs of the second, fourth, and sixth proportional integral controllers and inputting the same to the inverter to control the three-phase output voltage of the inverter by turning on / off the switching element of the inverter. An output voltage control device for a three-phase inverter comprising a drive unit. 2. The apparatus of claim 1, wherein the U, V, and W phase DC detectors comprise: a first multiplier that multiplies each input phase voltage by first phase information; a second multiplier that multiplies a predetermined reference voltage by second phase information; And an adder for adding the output of the second multiplier and the output of the first multiplier, respectively.