DISTRIBUTED POWER SUPPLY SYSTEM
First Claim
1. A distributed power supply system comprisingan inverter circuit having semiconductor switching elements connected in a three-phase bridge, anda control circuit which compares a predetermined carrier signal with voltage command signals of three phases and generates a control signal to control the semiconductor switching elements, wherein the distributed power supply system supplies AC power obtained by converting DC power to a power grid of a three-phase AC power supply,whereinthe power conversion system has a voltage detector which detects a grid voltage of the three-phase AC power supply, andthe control circuit has:
- three-phase fundamental wave signal generation means which generates a first fundamental wave signal, a second fundamental wave signal, and a third fundamental wave signal from the grid voltage detected by the voltage detector;
reference signal generation means which generates a first reference signal in phase with the first fundamental wave signal, based on the first to third fundamental wave signals;
third harmonic signal generation means which generates a third harmonic signal, using a triple harmonic signal generated based on the first reference signal, and the first to third fundamental wave signals outputted from the three-phase fundamental wave signal generation means; and
three-phase voltage command signal generation means which adds each of the first to third fundamental wave signals to each of the third harmonic signal and thus generates voltage command signals of three phases.
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Accused Products
Abstract
The disclosed distributed power supply system does not become disconnected from a grid simultaneously with others when the grid voltage falls instantaneously. In a distributed power supply device which controls an inverter circuit 10 based on a control signal obtained by comparing a predetermined carrier signal and voltage command signals of three phases and which converts DC power to AC power and supplies the AC power to a power grid of a three-phase AC power supply, fundamental wave signals of three phases are generated from a grid voltage of the three-phase AC power supply. A reference cosine wave signal is generated from the fundamental wave signals of three phases. A third harmonic signal is generated from the reference cosine wave signal and the fundamental wave signals of three phases. The three-phase fundamental wave signals and the third harmonic signal are added to generate voltage command signals of three phases.
18 Citations
4 Claims
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1. A distributed power supply system comprising
an inverter circuit having semiconductor switching elements connected in a three-phase bridge, and a control circuit which compares a predetermined carrier signal with voltage command signals of three phases and generates a control signal to control the semiconductor switching elements, wherein the distributed power supply system supplies AC power obtained by converting DC power to a power grid of a three-phase AC power supply, wherein the power conversion system has a voltage detector which detects a grid voltage of the three-phase AC power supply, and the control circuit has: -
three-phase fundamental wave signal generation means which generates a first fundamental wave signal, a second fundamental wave signal, and a third fundamental wave signal from the grid voltage detected by the voltage detector; reference signal generation means which generates a first reference signal in phase with the first fundamental wave signal, based on the first to third fundamental wave signals; third harmonic signal generation means which generates a third harmonic signal, using a triple harmonic signal generated based on the first reference signal, and the first to third fundamental wave signals outputted from the three-phase fundamental wave signal generation means; and three-phase voltage command signal generation means which adds each of the first to third fundamental wave signals to each of the third harmonic signal and thus generates voltage command signals of three phases. - View Dependent Claims (2, 3, 4)
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Specification