CN-122029734-A - Power regulator

Abstract

The controller calculates a positive current of the dq axis, an inverse current of the dq axis, a positive imaginary impedance, and an inverse imaginary impedance based on an output current or an output voltage of the ac side of the inverter. The controller calculates a first normal phase voltage of the three phases based on the normal phase current and the normal phase virtual impedance of the dq axis, and calculates a first reverse phase voltage of the three phases based on the reverse phase current and the reverse phase virtual impedance of the dq axis. The controller calculates a third phase positive voltage as a third phase first positive voltage when the positive current is equal to or higher than the first threshold value, calculates a third phase second positive voltage as zero when the positive current is lower than the first threshold value, calculates a third phase second negative voltage as a third phase first negative voltage when the negative current is equal to or higher than the second threshold value, and calculates a third phase second negative voltage as zero when the negative current is lower than the second threshold value. The controller controls the inverter based on a voltage command value obtained by subtracting the three-phase second normal phase voltage and the three-phase second reverse phase voltage from the three-phase voltage command generated based on the predetermined parameter.

Inventors

• M. Bani shamshi

Assignees

• 株式会社TMEIC

Dates

Publication Date

20260512

Application Date

20240902

Claims (6)

1. 1. A power conditioner, comprising: an inverter for converting DC power supplied from a DC power supply into AC power and supplying the AC power to a power system, and A controller for controlling the inverter, The controller is configured to be configured to, Based on the output current of the ac side of the inverter, the positive phase current of the dq axis is calculated, Calculating an inverted current of the dq axis based on an output current of an alternating current side of the inverter, Calculating a positive imaginary impedance for suppressing a positive current of an ac side of the inverter based on an output voltage of the ac side of the inverter, Calculating an inverted virtual impedance for suppressing an inverted current of an ac side of the inverter based on an output voltage of the ac side of the inverter, Calculating a first positive phase voltage of three phases based on the positive phase current of the dq axis and the positive phase imaginary impedance, Calculating a first inverted voltage of three phases based on the inverted current of the dq axis and the inverted imaginary impedance, Calculating a second positive phase voltage of three phases as a first positive phase voltage of the three phases when the positive phase current is above a first threshold value, calculating a second positive phase voltage of three phases as zero when the positive phase current is below the first threshold value, Calculating a second inverted voltage of three phases as a first inverted voltage of the three phases when the inverted current is above a second threshold, calculating the second inverted voltage of the three phases as zero when the inverted current is less than the second threshold, The inverter is controlled based on a voltage command value obtained by subtracting a second normal phase voltage of the three phases and a second reverse phase voltage of the three phases from a voltage command of the three phases generated according to a prescribed parameter.
2. 2. The power regulator of claim 1, wherein, The first positive phase voltage of the three phases is obtained by converting a positive phase voltage of the dq axis obtained by multiplying the positive phase current of the dq axis by the positive phase virtual impedance into a three-phase component, The first three-phase reverse voltage is obtained by converting a dq-axis reverse voltage obtained by multiplying the dq-axis reverse current by the reverse virtual impedance into a three-phase component.
3. 3. The power regulator of claim 1, wherein, The first threshold value is set based on a positive current estimated when an output voltage of all three-phase lines on an ac side of the inverter is smaller than a predetermined voltage, The second threshold value is set based on an inverted current estimated when an output voltage of two phases in a three-phase line on an ac side of the inverter is smaller than the predetermined voltage.
4. 4. The power regulator of claim 1, wherein, The first threshold value is a value set based on a positive-phase current estimated when an output voltage of two phases in a three-phase line of the inverter is smaller than a prescribed voltage, The second threshold value is set based on an inverted current estimated when an output voltage of one phase of the three-phase line of the inverter is smaller than the predetermined voltage.
5. 5. The power regulator of claim 1, wherein, The predetermined parameters include a phase command value, a d-axis voltage command value, and a q-axis voltage command value of the output voltage of the inverter calculated based on a parameter indicating dynamic characteristics of the synchronous generator, The three-phase voltage command is a voltage obtained by voltage control of a three-phase current command obtained by converting a d-axis positive-phase current command value and a q-axis positive-phase current command value generated from the phase command value, the d-axis voltage command value, and the q-axis voltage command value into three-phase components.
6. 6. The power regulator of claim 1, wherein, The predetermined parameters include a phase command value, a d-axis voltage command value, and a q-axis voltage command value of the output voltage of the inverter calculated based on a parameter indicating dynamic characteristics of the synchronous generator, The three-phase voltage command is a voltage obtained by converting a d-axis normal phase voltage command value and a q-axis normal phase voltage command value generated from the phase command value, the d-axis voltage command value, and the q-axis voltage command value into three-phase components.

Description

Power regulator Technical Field The present disclosure relates to techniques for controlling a power regulator. Background Patent document 1 discloses a power conversion device (power conditioner). Specifically, when the inverter-side inverter voltage is equal to or higher than a predetermined value, the power conditioner determines that the inverter is operated alone, and controls the inverter to stop. Prior art literature Patent literature Patent document 1 Japanese patent No. 7151911 Disclosure of Invention Problems to be solved by the invention However, when an unbalanced load is turned on the ac side of the inverter, the inverter current increases as the inverter voltage increases. In this case, the output current of the inverter may be equal to or greater than the rated current, and may be an overcurrent. An object of the present disclosure is to provide a technique capable of suppressing an ac side of an inverter from becoming an overcurrent even when an unbalanced load is turned on at the ac side of the inverter. Means for solving the problems One aspect of the present disclosure relates to a power regulator. The power conditioner includes an inverter that converts direct-current power supplied from a direct-current power supply into alternating-current power and supplies the alternating-current power to a power system, and a controller that controls the inverter. The controller calculates a positive current of the dq axis based on an output current of the ac side of the inverter, and calculates a negative current of the dq axis based on the output current of the ac side of the inverter. The controller calculates a positive imaginary impedance for suppressing a positive current on the ac side of the inverter based on the output voltage on the ac side of the inverter, and calculates an inverted imaginary impedance for suppressing an inverted current on the ac side of the inverter based on the output voltage on the ac side of the inverter. The controller calculates a first normal phase voltage of the three phases based on the normal phase current and the normal phase virtual impedance of the dq axis, and calculates a first reverse phase voltage of the three phases based on the reverse phase current and the reverse phase virtual impedance of the dq axis. The controller calculates a third phase positive voltage as a third phase first positive voltage when the positive current is equal to or higher than the first threshold value, calculates a third phase second positive voltage as zero when the positive current is lower than the first threshold value, calculates a third phase second negative voltage as a third phase first negative voltage when the negative current is equal to or higher than the second threshold value, and calculates a third phase second negative voltage as zero when the negative current is lower than the second threshold value. The controller controls the inverter based on a voltage command value obtained by subtracting the three-phase second normal phase voltage and the three-phase second reverse phase voltage from the three-phase voltage command generated based on the predetermined parameter. Effects of the invention According to the present disclosure, the positive phase current of the dq axis is calculated based on the output current of the ac side of the inverter, and the negative phase current of the dq axis is calculated based on the output current of the ac side of the inverter. Further, a positive imaginary impedance for suppressing a positive current on the ac side of the inverter is calculated based on the output voltage on the ac side of the inverter, and an inverted imaginary impedance for suppressing an inverted current on the ac side of the inverter is calculated based on the output voltage on the ac side of the inverter. The first positive phase voltage of the three phases is calculated based on the positive phase current and the positive phase virtual impedance of the dq axis, and the first negative phase voltage of the three phases is calculated based on the negative phase current and the negative phase virtual impedance of the dq axis. When the normal phase current is equal to or higher than a first threshold value, the second normal phase voltage of the three phases is calculated as the first normal phase voltage of the three phases, when the normal phase current is lower than the first threshold value, the second normal phase voltage of the three phases is calculated as zero, when the reverse phase current is equal to or higher than a second threshold value, the second reverse phase voltage of the three phases is calculated as the first reverse phase voltage of the three phases, and when the reverse phase current is lower than the second threshold value, the second reverse phase voltage of the three phases is calculated as zero. The inverter is controlled based on a voltage command value obtained by subtracting the three-phase second positive-phase voltage and the th