JP2006094598A - Inverter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inverter device wherein fluctuation in output voltage can be suppressed within a preset range and oscillation in input voltage can be suppressed. <P>SOLUTION: When the error between a command value and a detected value of output voltage is out of a preset range, the control gain of an error amplifier is increased or the time constant of a first-order lag filter is shortened. When the error is within the preset range, the control gain is reduced or the time constant of the first-order lag filter is lengthened. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inverter device that supplies a constant voltage and a constant frequency to a load.

FIG. 1 is a top view of an inverter device for supplying a constant voltage and a constant frequency to a load.
The inverter device 3 is configured to input a DC voltage from the DC power source 1 through the DC filter 2 and output the AC voltage to the load 5 through the AC filter 4.

  An error amplifier that outputs a voltage correction value by multiplying an error between the command value of the AC voltage and the detected value by a control gain, and a voltage command that outputs the correction voltage command by adding the voltage correction value to the command value of the AC voltage An arithmetic unit and a transformation rate computing unit that computes the transformation rate by dividing the correction voltage command by a value obtained by passing a first-order lag filter to the detected value of the DC voltage (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 09-009642

  The inverter device as described above has a disadvantage that the output voltage does not fluctuate when the control gain is increased or the time constant of the first-order lag filter is shortened, but the input voltage vibrates.

  In order to solve the above points, the present invention increases the control gain of the error amplifier when the error between the command value and the detection value of the AC voltage is outside the setting range, and decreases the control gain when the error is within the setting range. .

  Alternatively, the time constant of the first-order lag filter is shortened when the error between the command value of the AC voltage and the detected value is outside the setting range, and the time constant is lengthened when the error is within the setting range.

The present invention has the following effects.
1. The fluctuation of the output voltage can be suppressed within the set range.
2. The vibration of the input voltage can be suppressed.

  If the error between the command value and detection value of the AC voltage is outside the setting range, increase the control gain of the error amplifier, and if the error is within the setting range, decrease the control gain to keep the output voltage fluctuation within the setting range. The vibration of the input voltage can be suppressed while suppressing the noise.

  Alternatively, when the error between the command value and the detection value of the AC voltage is outside the setting range, the time constant of the first-order lag filter is shortened, and when the error is within the setting range, the time constant is lengthened, The vibration of the input voltage can be suppressed while suppressing the fluctuation within the set range.

The present invention is applied to the inverter device of FIG.
As shown in FIG. 1, the main circuit includes an inverter device 3 that receives a DC voltage from a DC power source 1 through a DC filter 2 and outputs an AC voltage to a load 5 through an AC filter 4.

  The control method includes an error amplifier that outputs a voltage correction value by multiplying an error between an AC voltage command value and a detection value by a control gain, and adds the voltage correction value to the AC voltage command value to output a correction voltage command. A voltage command calculator for output, and a conversion factor calculator for calculating the conversion factor by dividing the corrected voltage command by a value obtained by passing a first-order lag filter to the detected value of the DC voltage, and the command value and detected value of the AC voltage. If the error is outside the set range, the control gain of the error amplifier is increased or the time constant of the first-order lag filter is shortened. If the error is within the set range, the control gain is decreased or the time constant is increased.

  The present invention relates to an inverter device that supplies a constant voltage and a constant frequency to a load, and can suppress fluctuations in the input voltage while suppressing fluctuations in the output voltage within a set range.

Fig. 3 is a jump diagram of an inverter device that supplies a constant voltage and a constant frequency to a load.

Explanation of symbols

1 DC power supply 2 DC filter 3 Inverter device 4 AC filter 5 Load

Claims (2)

  An inverter device that inputs a DC voltage through a DC filter circuit and outputs an AC voltage through an AC filter circuit, and outputs a voltage correction value by multiplying an error between the command value and detection value of the AC voltage by a control gain. An error amplifier, a voltage command calculator that outputs the corrected voltage command by adding the voltage correction value to the command value of the AC voltage, and a value obtained by passing the correction voltage command to the detected value of the DC voltage through a first-order lag filter. In an inverter device equipped with a transformation ratio calculator that calculates the transformation ratio by dividing, if the error between the command value and the detection value of the AC voltage is outside the setting range, the control gain of the error amplifier is increased and the error is set. An inverter device characterized in that the control gain is lowered when it is within the range.   An inverter device that inputs a DC voltage through a DC filter circuit and outputs an AC voltage through an AC filter circuit, and outputs a voltage correction value by multiplying an error between the command value and detection value of the AC voltage by a control gain. An error amplifier, a voltage command calculator that outputs the corrected voltage command by adding the voltage correction value to the command value of the AC voltage, and a value obtained by passing the correction voltage command to the detected value of the DC voltage through a first-order lag filter. In an inverter device having a transformation rate calculator that calculates a transformation rate by dividing, if the error between the command value and the detection value of the AC voltage is outside the setting range, the time constant of the first-order lag filter is shortened, and the error is reduced. An inverter device characterized in that the time constant is lengthened within a set range.

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