JP5988911B2 - Inverter control device - Google Patents

Description

  The present invention relates to an inverter control device that controls an inverter that outputs a three-phase AC voltage.

  Conventionally, an inverter control device that controls a PWM inverter and outputs a three-phase AC voltage is known (see, for example, Patent Document 1). The inverter control device is generally required to make the output voltage of the inverter a stable voltage with little fluctuation.

  FIG. 2 is a diagram showing a configuration of a conventional inverter control device. Control of the inverter 10 by the inverter control device 2 shown in FIG. 2 will be described. In the inverter control device 2, the three-phase to two-phase conversion unit 102 converts the three-phase alternating current with a phase difference of 120 ° detected by the voltage detection unit 101 into a two-phase alternating current with a phase difference of 90 ° and converts the three-phase to two-phase. The wave rotation coordinate conversion unit 103 converts the voltage value of the two-phase alternating current into a direct current value by rotating the coordinate system together with the phase rotation.

  Then, the subtraction unit 105 obtains an error value between the output voltage value that has been subjected to the rotation coordinate conversion by the fundamental wave rotation coordinate conversion unit 103 and the voltage reference value that is output from the voltage reference value generation unit 104, and the error value is obtained as a proportional integration control unit. In 106, proportional-integral control (PI control) is performed. Then, the sum of the value output from the proportional integral control unit 106 and the voltage reference value output from the voltage reference value generation unit 104 is obtained by the addition unit 113, and the fundamental rotational coordinate inverse conversion unit 114 performs a two-phase AC direct current. The voltage value is converted from the original voltage value to the original AC value, and the two-phase / three-phase converter 115 converts the two-phase AC to the three-phase AC. Then, the inverter 10 is controlled by the inverter voltage command value output from the two-phase / three-phase converter 115. The output voltage of the inverter 10 is output to the DC load 30 through the AC filter 20.

JP 09-009642 A

  When the conventional inverter control device as described above is connected to a DC load having a rectifier, even if the voltage command value of the inverter is a sine wave, distortion of the load current occurs due to the non-linearity of the DC load having the rectifier. As a result, harmonics are generated in the output voltage, which adversely affects other loads connected in parallel.

  In addition, in the voltage control method based on commonly used output voltage coordinate conversion and proportional-integral control, the harmonic voltage cannot be reduced at all by the integral element, but to some extent by increasing the control gain in the proportional element. However, there is a phase delay due to the AC filter, and if the control gain is increased, the harmonic becomes unstable. Therefore, measures such as limiting the load capacity that can be used are necessary. If the harmonic component is large, a filter circuit is inserted immediately before the load, or for a load that has a rectifier separately from the power supply of the normal load. There was a problem that measures such as preparing a power supply were necessary.

  Also, in the conventional inverter control device, current flows through a diode connected in parallel with the switching element of the inverter part during the PWM control dead time, so that a different voltage is output depending on the direction of the current, and the output voltage is distorted and reduced. There was a problem of becoming.

  The object of the present invention made in view of such circumstances is to prevent the harmonic distortion generated when connected to a DC load having a rectifier and the voltage distortion caused by dead time without affecting the harmonics of other frequencies. It is an object of the present invention to provide an inverter control device that is reduced, has high harmonics, has high quality, and can reduce the size and cost of a circuit by reducing the number of components.

  In order to solve the above-mentioned problem, an inverter control device according to the present invention is an inverter control device that controls an inverter that outputs three-phase alternating current via an alternating current filter, and means for detecting an output voltage value of the alternating current filter, After the three-phase two-phase conversion of the output voltage value of the AC filter, a means for generating a converted voltage value obtained by rotating coordinate conversion at the three-phase AC fundamental frequency, and a voltage error value of the converted voltage value and the output voltage reference value Means for calculating a first gain adjustment value and a second gain adjustment value by multiplying the voltage error value by a control gain; and Means for generating a first value obtained by rotating the coordinates at a frequency of 6 times and a second value obtained by rotating the coordinates of the second gain adjustment value at a frequency that is -6 times the fundamental frequency; of Means for calculating a first integral value obtained by integrating the second value, and a second integral value obtained by integrating the second value, and the first integral value is inversely transformed at a frequency six times the fundamental frequency. Means for generating a second inverse transformed value obtained by inversely transforming the first inverse transformed value and the second integrated value at a frequency that is -6 times the fundamental frequency; and the converted voltage value is converted into the voltage error. Means for calculating a voltage instruction value by adding a value feedback-controlled so as to reduce the value, the first inverse transformation value, and the second inverse transformation value; and rotating the voltage instruction value at the fundamental frequency And means for outputting the value obtained by performing the two-phase / three-phase transformation to the inverter as an output voltage command value after the coordinate reverse transformation is performed.

  Further, in the inverter control device according to the present invention, further, current detecting means for detecting a current value flowing through the capacitor of the AC filter, and three-phase two-phase conversion of the current value flowing through the capacitor of the AC filter, the basic Means for generating a converted current value obtained by rotating coordinate conversion at a frequency; means for calculating a current difference value between the converted current value and the current reference value; and multiplying the current difference value by a control gain to obtain a third gain Means for calculating an adjustment value, a fourth gain adjustment value, and a fifth gain adjustment value; a third value obtained by rotationally converting the third gain adjustment value at a frequency six times the fundamental frequency; and Means for generating a fourth value obtained by rotationally transforming the fourth gain adjustment value at a frequency -6 times the fundamental frequency; a third integrated value obtained by integrating the third value; and the fourth Integrate the value of Means for calculating a fourth integral value, a third inverse transform value obtained by inversely transforming the third integral value at a frequency six times the fundamental frequency, and the fourth integral value as the fundamental value. Means for generating a fourth inverse transformation value obtained by inverse transformation of rotational coordinates at a frequency -6 times the frequency, the third inverse transformation value, the fourth inverse transformation value, and the fifth gain adjustment value. Means for adding the sum to the voltage instruction value.

  In the inverter control device according to the present invention, a difference between an input current value of the AC filter and an output current value of the AC filter is used instead of the current value flowing through the capacitor of the AC filter.

  The inverter control device according to the present invention is characterized in that the input current value of the AC filter is used instead of the current value flowing through the capacitor of the AC filter.

  According to the present invention, harmonic components generated when a DC load having a rectifier is connected can be reduced. Therefore, it is possible to relax restrictions on the capacity of a DC load having a rectifier.

  In addition, according to the present invention, the filter conventionally provided on the input side of the DC load having the rectifier can be omitted, so that the circuit can be reduced in size and cost by reducing the number of components.

  In addition, according to the present invention, a DC load having a rectifier and an AC load that requires an AC power supply with less harmonics can be used in a common inverter.

  Further, according to the present invention, voltage distortion caused by the dead time of the inverter device can be reduced.

It is a block diagram which shows the structure of the inverter control apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the inverter control apparatus by the conventional coordinate transformation and proportional integral control. It is a figure which shows the voltage reference value of a three-phase alternating current at the time of using the inverter control apparatus which concerns on one Embodiment of this invention, the output voltage of an inverter, and the output voltage of an alternating current filter. It is a figure which shows the Lissajous waveform of the voltage which carried out the three-phase two-phase conversion of the output voltage of an alternating current filter at the time of using the inverter control apparatus which concerns on one Embodiment of this invention. It is a figure which shows the voltage which carried out the three-phase two-phase conversion and the rotation coordinate conversion of the output voltage of an alternating current filter at the time of using the inverter control apparatus which concerns on one Embodiment of this invention. It is a figure which shows the voltage reference value of a three-phase alternating current at the time of using the conventional inverter control apparatus, the output voltage of an inverter, and the output voltage of an alternating current filter. It is a figure which shows the Lissajous waveform of the voltage which carried out the three-phase two-phase conversion of the output voltage of an alternating current filter at the time of using the conventional inverter control apparatus. It is a figure which shows the voltage which carried out the three-phase two-phase conversion and the rotation coordinate conversion of the output voltage of an alternating current filter at the time of using the conventional inverter control apparatus.

  Hereinafter, an embodiment of an inverter control device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an inverter control apparatus according to an embodiment of the present invention. As shown in FIG. 1, the inverter control device 1 includes a voltage detection unit 101, a three-phase two-phase conversion unit 102 (102-1 and 102-2), and a fundamental wave rotation coordinate conversion unit 103 (103-1 and 103). -2), voltage reference value generation unit 104, subtraction unit 105 (105-1 and 105-2), proportional-integral control unit 106, gain multiplication unit 107 (107-1 to 107-5), 6 Double frequency rotation coordinate conversion unit 108 (108-1 and 108-2), -6 frequency rotation coordinate conversion unit 109 (109-1 and 109-2), and integration unit 110 (110-1 to 110-4) A 6-fold frequency rotation coordinate inverse conversion unit 111 (111-1 and 111-2), a -6-times frequency rotation coordinate inverse conversion unit 112 (112-1 and 112-2), and an addition unit 113 (113-1). To 113-6) and fundamental wave rotation coordinates It comprises a conversion unit 114, a two-phase three-phase conversion unit 115, and a current reference value generator 116.

  The inverter control device 1 controls the inverter 10 that outputs a three-phase AC voltage via the AC filter 20.

  The voltage detection unit 101 detects an output voltage value (AC filter output voltage value) a output from the AC filter 20.

  The three-phase to two-phase conversion unit 102-1 performs three-phase to two-phase conversion on the AC filter output voltage value a detected by the voltage detection unit 101, and converts the three-phase AC having a phase difference of 120 ° to a phase difference of 90 °. Convert to two-phase alternating current.

  The fundamental wave rotation coordinate conversion unit 103-1 rotates at the three-phase AC fundamental frequency (50 Hz or 60 Hz) with respect to the AC filter output voltage value that has been three-phase to two-phase converted by the three-phase to two-phase conversion unit 102-1. Coordinate conversion (dq conversion) is performed to convert a two-phase AC voltage value into a DC value. By this rotational coordinate conversion, the three-phase AC fundamental wave component output from the AC filter 20 is converted to DC. When the three-phase AC output from the AC filter 20 includes a harmonic having a frequency -5 times that of the fundamental wave and a harmonic having a frequency seven times that of the fundamental wave, the voltage after the rotation coordinate conversion includes A harmonic having a frequency of ± 6 times the wave is included. Here, the negative frequency means a frequency in which the rotation direction of the frequency vector is opposite to the positive frequency.

  The subtracting unit 105-1 subtracts the AC filter output voltage value coordinate-converted by the fundamental wave rotation coordinate converting unit 103-1 and the output voltage reference value generated by the voltage reference value generating unit 104 to obtain a voltage error value. Ask.

  The proportional-integral control unit 106 performs proportional-integral control (PI control) on the voltage error value calculated by the subtracting unit 105-1. In this embodiment, PI control is performed. However, any control may be used as long as feedback control is performed to reduce the voltage error value. For example, P control or PID control may be used.

  The adder 113-1 adds the output value of the proportional-plus-integral controller 106 and the output voltage reference value generated by the voltage reference value generator 104. That is, the output value of the adder 113-1 is a value obtained by performing feedback control on the output value of the fundamental wave rotation coordinate converter 103-1 so that the voltage error value calculated by the subtractor 105-1 is small.

  Gain multipliers 107-1 and 107-2 adjust the amplitude by multiplying the voltage error value calculated by subtractor 105-1 by the control gain.

  The 6-fold frequency rotation coordinate conversion unit 108-1 performs rotation coordinate conversion of the value whose amplitude is adjusted by the gain multiplication unit 107-1 at a frequency 6 times the fundamental frequency of the three-phase alternating current, and a frequency 6 times the fundamental wave. DC harmonics. In this process, for the three-phase alternating current output from the alternating-current filter 20, rotational coordinate conversion is performed at a frequency seven times the fundamental frequency of the three-phase alternating current, and harmonics having a frequency seven times the fundamental wave are converted to direct current. This is equivalent to

  The −6 times frequency rotation coordinate conversion unit 109-1 performs the rotation coordinate conversion of the value whose amplitude is adjusted by the gain multiplication unit 107-2 at a frequency that is −6 times the fundamental frequency of the three-phase alternating current, and the fundamental wave −6 Convert harmonics of double frequency to DC. In this process, for the three-phase alternating current output from the alternating-current filter 20, rotational coordinate conversion is performed at a frequency that is -5 times the fundamental frequency of the three-phase alternating current, and a harmonic having a frequency that is -5 times the fundamental wave. Is equivalent to DC.

  The integrating unit 110-1 calculates an integrated value obtained by integrating the values obtained by rotating coordinate conversion by the 6-times frequency rotating coordinate converting unit 108-1. The integration unit 110-2 calculates an integral value obtained by integrating the values that have been subjected to the rotation coordinate conversion by the −6 × frequency rotation coordinate conversion unit 109-1.

  The 6-fold frequency rotation coordinate reverse conversion unit 111-1 performs reverse rotation coordinate conversion of the integrated value integrated by the integration unit 110-1 at a frequency that is 6 times the three-phase AC fundamental frequency. The −6 × frequency rotation coordinate reverse conversion unit 112-1 performs the reverse rotation coordinate conversion of the integration value integrated by the integration unit 110-2 at a frequency that is −6 times the fundamental frequency of the three-phase alternating current.

  The adder 113-2 adds the output value of the 6 × frequency rotation coordinate reverse conversion unit 111-1 and the output value of the −6 time frequency rotation coordinate reverse conversion unit 112-1. The adder 113-3 adds the output value of the adder 113-1 and the output value of the adder 113-2 to obtain a voltage instruction value c.

  As the AC filter 20, an LC filter composed of a coil and a capacitor is generally used. The AC filter 20 includes a current detection unit 21. The current detection unit 21 detects the value of the current flowing through the capacitor of the AC filter 20 (AC filter capacitor current value) b.

  In the present embodiment, control is performed using the AC filter capacitor current value b as described below. However, instead of the AC filter capacitor current value b, the input current value of the AC filter 20 and the output current value of the AC filter 20 are The difference may be used. Further, instead of the AC filter capacitor current value b, the input current value of the AC filter 20 may be used.

  The three-phase to two-phase converter 102-2 performs three-phase to two-phase conversion on the AC filter capacitor current value b detected by the current detector 21, and converts the three-phase AC having a phase difference of 120 ° to a phase difference of 90 °. Convert to two-phase alternating current.

  The fundamental wave rotation coordinate conversion unit 103-2 performs a rotation coordinate conversion (d−) at a three-phase AC fundamental frequency with respect to the AC filter capacitor current value subjected to the three-phase / two-phase conversion by the three-phase / two-phase conversion unit 102-2. q conversion) to convert a two-phase AC current value into a DC value.

  The subtracting unit 105-2 subtracts the AC filter capacitor current value coordinate-converted by the fundamental wave rotation coordinate converting unit 103-2 from the output current reference value generated by the current reference value generating unit 116, and obtains a current error value. Ask for.

  The gain multipliers 107-3 to 107-5 adjust the amplitude by multiplying the current error value calculated by the subtractor 105-2 by the control gain.

  The 6-fold frequency rotation coordinate conversion unit 108-2 performs the rotation coordinate conversion of the value whose amplitude is adjusted by the gain multiplication unit 107-3 at a frequency that is 6 times the fundamental frequency of the three-phase alternating current. The −6 times frequency rotation coordinate conversion unit 109-2 performs the rotation coordinate conversion of the value whose amplitude is adjusted by the gain multiplication unit 107-4 at a frequency that is −6 times the basic frequency of the three-phase alternating current.

  The integrating unit 110-3 calculates an integrated value obtained by integrating the values obtained by rotating coordinate conversion by the 6-times frequency rotating coordinate converting unit 108-2. The integrating units 110-3 and 110-4 calculate an integrated value obtained by integrating the values that have been subjected to the rotation coordinate conversion by the −6 × frequency rotation coordinate conversion unit 109-2.

  The 6-fold frequency rotation coordinate reverse conversion unit 111-2 reverse-rotates the rotation coordinate at a frequency that is six times the fundamental frequency of the three-phase alternating current, integrated by the integration unit 110-3. The −6 × frequency rotation coordinate reverse conversion unit 112-2 performs reverse rotation coordinate conversion of the integral value integrated by the integration unit 110-4 at a frequency that is −6 times the fundamental frequency of the three-phase AC.

  The adding unit 113-4 adds the output value of the 6 × frequency rotation coordinate reverse conversion unit 111-2 and the output value of the −6 time frequency rotation coordinate reverse conversion unit 112-2. The adder 113-5 adds the output value of the adder 113-4 and the output value of the gain multiplier 107-5 to obtain a current value calculation result d. The adding unit 113-6 adds the voltage instruction value c calculated by the adding unit 113-3 and the current value calculation result d calculated by the adding unit 113-5.

  The fundamental wave rotation coordinate reverse conversion unit 114 performs rotation coordinate reverse conversion (qd conversion) on the value calculated by the addition unit 113-6 at a three-phase AC fundamental frequency, and converts the DC value to two. Convert to phase alternating current.

  The two-phase / three-phase conversion unit 115 performs two-phase / three-phase conversion on the value subjected to the rotation coordinate reverse conversion by the fundamental wave rotation coordinate reverse conversion unit 114, and converts a two-phase alternating current with a phase difference of 90 ° into a phase difference of 120 °. Convert to three-phase AC. Then, this value is used as the output voltage command value of the inverter 10 to control the output voltage of the inverter 10.

  Thus, the inverter control apparatus 1 controls as follows using the AC filter output voltage value a. Three-phase two-phase conversion unit 102-1 performs three-phase two-phase conversion on the AC filter output voltage value a, and the fundamental wave rotation coordinate conversion unit 103-1 performs rotation coordinate conversion at a three-phase AC fundamental frequency. A voltage value is generated, and the subtraction unit 105-1 calculates a voltage error value between the converted voltage value and the output voltage reference value. Then, the gain multipliers 107-1 and 107-2 calculate the first gain adjustment value and the second gain adjustment value by multiplying the voltage error value by the control gain, and the 6-fold frequency rotation coordinate conversion. The unit 108-1 generates a first value obtained by rotating the first gain adjustment value at a frequency six times the fundamental frequency of the three-phase alternating current, and the -6 times frequency rotated coordinate conversion unit 109-1 Then, a second value obtained by rotationally converting the second gain adjustment value at a frequency that is −6 times the fundamental frequency of the three-phase alternating current is generated, and the first values are obtained by the integrating units 110-1 and 110-2. A first integrated value obtained by integrating the second value and a second integrated value obtained by integrating the second value are calculated, and the 6th frequency rotation coordinate inverse transform unit 111-1 converts the first integrated value to the 6th value. A first inverse transformation value obtained by inverse transformation of the rotational coordinate at the double frequency is generated, and the −6 double frequency rotational coordinate inverse transformation unit 11 is generated. At -1, to produce a second inverse conversion value of the second integral value obtained by rotating the coordinate reverse conversion at the -6 times the frequency. Then, in the adders 113-1 to 113-3, the converted voltage value is feedback-controlled (for example, PI control) so that the voltage error value becomes small, the first inverse converted value, and the first 2 is added to calculate the voltage instruction value c, and the fundamental wave rotation coordinate inverse conversion unit 114 performs inverse rotation conversion of the voltage instruction value c at the three-phase AC fundamental frequency to obtain a two-phase three-phase. The conversion unit 115 outputs the value obtained by the two-phase / three-phase conversion to the inverter 10 as an output voltage command value.

  By adopting such a configuration, according to the present invention, it is possible to reduce harmonic components generated when a DC load 30 having a rectifier is connected. Therefore, the capacity limitation of the DC load 30 having the rectifier can be relaxed, and the filter conventionally provided on the input side of the DC load 30 having the rectifier can be omitted, and the circuit can be reduced in size and cost by reducing the number of components. Can be realized. Moreover, it becomes possible to use a DC load 30 having a rectifier and an AC load that requires an AC power supply with less harmonics in a common inverter. Furthermore, the voltage distortion resulting from the dead time of the inverter 10 can be reduced.

  Further, the inverter control device 1 may further control using the AC filter capacitor current value b as follows. The AC filter capacitor current value b is three-phase to two-phase converted by the three-phase to two-phase conversion unit 102-2, and the three-phase to two-phase converted current value is converted to the three-phase by the fundamental wave rotation coordinate conversion unit 103-2. A converted current value is generated by rotating coordinate conversion at an alternating fundamental frequency, and a current difference value between the converted current value and the current reference value is calculated by the subtracting unit 105-2. Then, the gain multipliers 107-3 to 107-5 multiply the current difference value by the control gain to obtain the third gain adjustment value, the fourth gain adjustment value, and the fifth gain adjustment value. The third value obtained by calculating and rotating the third gain adjustment value at a frequency six times the fundamental frequency of the three-phase alternating current is generated by the 6-fold frequency rotation coordinate conversion unit 108-2, and −6 A double frequency rotation coordinate conversion unit 109-2 generates a fourth value obtained by rotating the fourth gain adjustment value at a frequency that is −6 times the fundamental frequency of the three-phase alternating current, the integration unit 110-3, In 110-4, a third integrated value obtained by integrating the third value and a fourth integrated value obtained by integrating the fourth value are calculated, and the 6-times frequency rotation coordinate inverse conversion unit 111-2 is calculated. To generate a third inverse transformed value obtained by inversely transforming the third integrated value at a frequency six times the rotational coordinate. At -6-fold frequency rotating coordinate reverse conversion unit 112-2, and generates an inverse transform value of the fourth rotated coordinate inverse transforming said fourth integration value at the -6 times the frequency. Then, the addition units 113-4 to 113-6 add the sum of the third inverse transformation value, the fourth inverse transformation value, and the fifth gain adjustment value to the voltage instruction value c. . By adopting such a configuration, it is possible to further reduce the voltage distortion caused by the harmonic voltage and dead time generated when connected to a DC load having a rectifier.

  Simulation waveforms of the inverter control apparatus 1 according to the embodiment of the present invention shown in FIG. 1 are shown in FIGS. FIG. 3 is a diagram illustrating a three-phase AC voltage reference value, an output voltage of the inverter 10, and an output voltage of the AC filter 20 when the inverter control device 1 is used. Here, Vuref, Vvref, and Vwref are sine waves without distortion obtained from the voltage reference value. Vucom, Vvcom, Vwcom are output voltages of the inverter 10 as a result of the control calculation. Vcu, Vcv, and Vcw are output voltages of the AC filter 20.

  FIG. 4 is a diagram illustrating a Lissajous waveform of a voltage obtained by performing three-phase to two-phase conversion on the output voltage of the AC filter 20. Here, Va and Vb are voltages obtained by three-phase to two-phase conversion of the above Vcu, Vcv, and Vcw, and Va is the x axis and Vb is the y axis. When a sine wave without distortion obtained from the voltage reference value is three-phase to two-phase converted and a Lissajous waveform is drawn, a perfect circle is obtained.

  FIG. 5 is a diagram illustrating a waveform obtained by rotational coordinate conversion (dq conversion) of a two-phase AC obtained by three-phase to two-phase conversion of the output voltage of the AC filter 20. Here, Vd and Vq are voltages obtained by converting the above Va and Vb into rotational coordinates. When a waveform obtained by rotating a two-phase alternating current obtained by three-phase to two-phase conversion of an undistorted sine wave obtained from a voltage reference value is drawn, Vd and Vq are substantially straight lines with little pulsation.

  Next, simulation waveforms of the conventional inverter control device 2 shown in FIG. 2 are shown in FIGS. FIG. 6 is a diagram illustrating a three-phase AC voltage reference value, an output voltage of the inverter 10, and an output voltage of the AC filter 20 when the inverter control device 2 is used. Here, Vuref, Vvref, and Vwref are sine waves without distortion obtained from the voltage reference value. Vucom ', Vvcom', and Vwcom 'are output voltages of the inverter 10 as a result of the control calculation. Vcu ′, Vcv ′, and Vcw ′ are output voltages of the AC filter 20.

  FIG. 7 is a diagram illustrating a Lissajous waveform of a voltage obtained by performing three-phase to two-phase conversion on the output voltage of the AC filter 20. Here, Va ′ and Vb ′ are voltages obtained by three-phase to two-phase conversion of the above Vcu ′, Vcv ′, and Vcw ′, and Va ′ is the x axis and Vb ′ is the y axis.

  FIG. 8 is a diagram showing a waveform obtained by rotational coordinate conversion (dq conversion) of a two-phase alternating current obtained by three-phase two-phase conversion of the output voltage of the alternating-current filter 20. Here, Vd ′ and Vq ′ are voltages obtained by rotationally converting the above Va ′ and Vb ′.

  As is clear from a comparison between the waveform of the inverter control device 1 according to the embodiment of the present invention shown in FIGS. 3 to 5 and the waveform of the conventional inverter control device 2 shown in FIGS. According to the present invention, harmonic components generated when a DC load 30 having a rectifier is connected can be reduced. In the illustrated simulation waveform, voltage distortion due to dead time is not added, but voltage distortion due to dead time can be reduced by reducing harmonic components according to the present invention.

  The above embodiments have been described as typical examples, but it will be apparent to those skilled in the art that changes and substitutions can be made within the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, a plurality of constituent blocks shown in FIG. 1 can be combined into one, or one constituent block can be divided.

  According to the present invention, it is possible to reduce harmonic voltage generated when connected to a DC load having a rectifier and voltage distortion due to dead time, and to provide a high-quality power source with less harmonics, and to reduce the size of the circuit. Therefore, the present invention is useful for any application for controlling an inverter.

DESCRIPTION OF SYMBOLS 1 Inverter control apparatus 10 Inverter 20 AC filter 21 Current detection part 30 DC load 101 Voltage detection part 102 Three-phase two-phase conversion part 103 Fundamental wave rotation coordinate conversion part 104 Voltage reference value generation part 105 Subtraction part 106 Proportional integral control part 107 Gain Multiplication unit 108 6th frequency rotation coordinate conversion unit 109 −6th frequency rotation coordinate conversion unit 110 integration unit 111 6th frequency rotation coordinate reverse conversion unit 112 −6th frequency rotation coordinate reverse conversion unit 113 addition unit 114 fundamental wave rotation coordinate reverse Converter 115 Two-phase three-phase converter 116 Current reference value generator

Claims (4)

In an inverter control device that controls an inverter that outputs three-phase alternating current through an alternating current filter,
Means for detecting an output voltage value of the AC filter;
Means for generating a converted voltage value obtained by performing rotational coordinate conversion at the fundamental frequency of the three-phase alternating current after three-phase two-phase conversion of the output voltage value of the alternating-current filter;
Means for calculating a voltage error value of the converted voltage value and the output voltage reference value;
Means for multiplying the voltage error value by a control gain to calculate a first gain adjustment value and a second gain adjustment value;
The first gain adjustment value is rotationally coordinate-transformed at a frequency six times the fundamental frequency, and the second gain adjustment value is rotationally coordinate-transformed at a frequency -6 times the fundamental frequency. Means for generating a second value;
Means for calculating a first integrated value obtained by integrating the first value and a second integrated value obtained by integrating the second value;
A first inverse transformed value obtained by inversely transforming the first integral value at a frequency six times the fundamental frequency, and an inverse transformed rotational coordinate at the frequency -6 times the fundamental frequency, the second integral value. Means for generating the second inverse transformed value,
Means for calculating a voltage instruction value by adding a value obtained by feedback-controlling the conversion voltage value so that the voltage error value is small, the first inverse conversion value, and the second inverse conversion value;
Means for outputting a value obtained by performing two-phase three-phase conversion to the inverter as an output voltage command value after inversely transforming the voltage instruction value at the fundamental frequency and rotating coordinates;
An inverter control device comprising: Furthermore, current detection means for detecting a current value flowing through the capacitor of the AC filter,
Means for generating a converted current value obtained by performing rotational coordinate conversion at the fundamental frequency after three-phase to two-phase conversion of the current value flowing through the capacitor of the AC filter;
Means for calculating a current difference value between the converted current value and the current reference value;
Means for multiplying the current difference value by a control gain to calculate a third gain adjustment value, a fourth gain adjustment value, and a fifth gain adjustment value;
A third value obtained by rotating coordinate transformation of the third gain adjustment value at a frequency six times the fundamental frequency and a fourth value obtained by rotating coordinate transformation of the fourth gain adjustment value at a frequency -6 times the fundamental frequency. Means for generating a value of 4;
Means for calculating a third integrated value obtained by integrating the third value and a fourth integrated value obtained by integrating the fourth value;
A third inverse transformed value obtained by inversely transforming the third integrated value at a frequency six times the fundamental frequency and an inverse transformed rotational coordinate at the frequency -6 times the fundamental frequency. Means for generating the fourth inverse transformed value;
Means for adding a sum of the third inverse transformation value, the fourth inverse transformation value, and the fifth gain adjustment value to the voltage instruction value;
The inverter control device according to claim 1, comprising:   The inverter control device according to claim 2, wherein a difference between an input current value of the AC filter and an output current value of the AC filter is used instead of the current value flowing through the capacitor of the AC filter. The inverter control device according to claim 2, wherein an input current value of the AC filter is used instead of a current value flowing through a capacitor of the AC filter.