Power generation system and method of controlling same

Patent metadata

Field	Value
Publication number	US-10778128-B2
Application number	US-201616473877-A
Country	US
Kind code	B2
Filing date	Dec 27, 2016
Priority date	Dec 27, 2016
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

A power generation system includes a continuously variable transmission, a power generator, a transmission driving device, an output-side speed detector, and electric power load device, and a controller. The electric power load calculation device detects current values and current values of respective phases of three-phase alternating current generated by the power generator, calculates electric power load of the power generator based on the detected values, and executes filtering by attenuating a higher harmonic of a set frequency when calculating the electric power load of the power generator. The controller executes feedback control of calculating and outputting a gear change command to the transmission driving device so an output-side rotational speed detected by the output-side speed detector becomes equal to an output-side target rotational speed corresponding to the set frequency. The controller also executes feedforward compensation of correcting the gear change command, based on the calculated electric power load.

First claim

The invention claimed is:

1. A power generation system comprising:
a continuously variable transmission including a transmission mechanism configured to steplessly change a speed change ratio, the continuously variable transmission being configured to transmit a rotational speed of an input shaft to an output shaft at the speed change ratio changed by the transmission mechanism;
a power generator driven by rotation of the output shaft to generate three-phase AC power;
a transmission driving device configured to drive the transmission mechanism such that the speed change ratio of the continuously variable transmission is changed to a commanded gear change value corresponding to an input gear change command;
an output-side speed detector configured to detect an output-side rotational speed that is a rotational speed of the output shaft;
an electric power load calculation device configured to calculate electric power load of the power generator; and
a controller configured to output the gear change command corresponding to a detection result of the output-side speed detector and the electric power load calculated by the electric power load calculation device, control the speed change ratio of the continuously variable transmission, and make the power generator generate the three-phase AC power of a predetermined set frequency, wherein:
the electric power load calculation device includes a current detector, a voltage detector, and a calculator;
the current detector detects current values of respective phases of a three-phase alternating current generated by the power generator;
the voltage detector detects voltage values of the respective phases of the three-phase alternating current generated by the power generator;
the calculator calculates the electric power load of the power generator based on the current values detected by the current detector and the voltage values detected by the voltage detector, and executes filtering work of attenuating a higher harmonic of the set frequency when calculating the electric power load of the power generator;
the controller includes a feedback control portion and a feedforward compensation portion;
the feedback control portion executes feedback control of calculating the gear change command and outputting the obtained gear change command to the transmission driving device such that the output-side rotational speed detected by the output-side speed detector becomes equal to an output-side target rotational speed corresponding to the set frequency; and
the feedforward compensation portion executes feedforward compensation of correcting the gear change command, calculated by the feedback control portion, based on the electric power load of the power generator, the electric power load being calculated by the calculator.

2. The power generation system according to claim 1 , wherein:
the calculator includes a pre-filter; and
before the electric power load is calculated, the pre-filter executes filtering work of attenuating the higher harmonic of the set frequency with respect to the detected current values of three phases and the detected current values of the three phases.

3. The power generation system according to claim 2 , wherein:
the calculator includes a post-filter; and
the post-filter executes filtering work of attenuating the higher harmonic of the set frequency with respect to the calculated electric power load.

4. The power generation system according to claim 1 , wherein:
the calculator includes a post-filter; and
the post-filter executes filtering work of attenuating the higher harmonic of the set frequency with respect to the calculated electric power load.

5. The power generation system according to claim 4 , wherein the post-filter includes:
a band elimination filter configured to attenuate a second higher harmonic of the set frequency; and
a low pass filter configured to attenuate an N-th higher harmonic (N=3, 4, . . . ) of the set frequency.

6. The power generation system according to claim 5 , wherein:
the feedforward compensation portion executes filtering work of
converting the electric power load calculated by the electric power load calculation device into a speed value,

subjecting the converted electric power load as the speed value to phase compensation through a dead zone filter, and
integrating the compensated electric power load; and
the feedforward compensation portion corrects the gear change command, calculated by the feedback control portion, by using as a compensation value the electric power load subjected to the filtering work.

7. A method of controlling a power generation system in which:
a power generator is driven to generate three-phase AC power by rotation of an output shaft of a continuously variable transmission including a transmission mechanism configured to steplessly change a speed change ratio of the output shaft to an input shaft; and
a transmission driving device drives the transmission mechanism such that the speed change ratio of the continuously variable transmission is changed to a commanded gear change value corresponding to an input gear change command,
the power generation system being configured to make the power generator generate the three-phase AC power of a predetermined set frequency,
the method comprising:
a current detecting step of detecting current values of respective phases of a three-phase alternating current generated by the power generator;
a voltage detecting step of detecting voltage values of the respective phases of the three-phase alternating current generated by the power generator;
a calculating step of calculating electric power load of the power generator based on the current values detected in the current detecting step and the voltage values detected in the voltage detecting step and executing filtering work of attenuating a higher harmonic of the set frequency when calculating the electric power load of the power generator;
a speed detecting step of detecting an output-side rotational speed that is a rotational speed of the output shaft;
a feedback control step of executing feedback control of calculating the gear change command and outputting the obtained gear change command to the transmission driving device such that the output-side rotational speed detected in the speed detecting step becomes equal to an output-side target rotational speed corresponding to the set frequency; and
a feedforward compensation step of executing feedforward compensation of correcting the gear change command, calculated in the feedback control step, based on the electric power load of the power generator, the electric power load being calculated in the calculating step.

Assignees

• Kawasaki Heavy Ind Ltd

Inventors

• Goi Tatsuhiko
• Nakashima Kenichi
• Otsuki Satoshi
• Sugimoto Kazushige
• Higashi Masaaki

Classifications

• F16H61/664

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• F16H59/40

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• H02P2101/30

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• H02P2101/25

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• F16H2061/0012

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