Parallel connection of different types of AC power supplies of differing capacities
First Claim
1. A power inverting method capable of parallel-connecting a plurality of power supply units to a common bus line, comprising the steps of:
- entering a plurality of input commands for changing a parameter of an AC (alternating current) output voltage of a power inverter employed in one power supply unit;
detecting a variation in an AC output current of said one power supply unit when the AC output voltage of said power inverter is changed;
processing said variation in the AC output current to infer a desirable parameter required to share AC power which should be derived from said one power supply unit with respect to total output power capable of being supplied from said common bus line to a load; and
controlling said one power supply unit to output a desirable voltage in response to said desirable parameter, whereby said power sharing operation for said one power supply unit is achieved independently of other power sharing operations for other power supply units.
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Abstract
A power inverting method and system for connecting a plurality of AC power supplies to a common bus line in parallel wherein the AC power supplies are independently controlled so that power supplies with different rating characteristics can be coupled to the common bus line without adverse effects such as the existence of cross currents flowing between the different power supplies. In each AC power supply there is provided a system parameter calculating unit for calculating optimum load current, system impedance and output voltage parameters of the power supply which are then output to a reference data producing unit which generates appropriate feedback voltage and phase signals for output to a voltage controller and a phase synchronization controller, respectively. The voltage controller and phase synchronization controller output feedback signals to a power inverter which varies the power supply output. Using such feedback control in each of the plurality of power supply units enables a constant current to be output to a load on the system and eliminates the possibility of cross currents between the various power supply units.
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Citations
13 Claims
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1. A power inverting method capable of parallel-connecting a plurality of power supply units to a common bus line, comprising the steps of:
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entering a plurality of input commands for changing a parameter of an AC (alternating current) output voltage of a power inverter employed in one power supply unit; detecting a variation in an AC output current of said one power supply unit when the AC output voltage of said power inverter is changed; processing said variation in the AC output current to infer a desirable parameter required to share AC power which should be derived from said one power supply unit with respect to total output power capable of being supplied from said common bus line to a load; and controlling said one power supply unit to output a desirable voltage in response to said desirable parameter, whereby said power sharing operation for said one power supply unit is achieved independently of other power sharing operations for other power supply units. - View Dependent Claims (2)
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3. A power inverting system comprising:
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a plurality of power supply units each having a power inverter and parallel-connected to a common bus line; means for detecting a variation contained in an AC output current of one power supply unit when a command for changing an amplitude of an AC output voltage of the power inverter of said one power supply unit is issued; means for processing said variation in the AC output current to infer a desirable parameter required to share AC power which should be derived from said one power supply unit with respect to total power output capable of being supplied from said common bus line to a load; and means for controlling said one power supply unit to output a desirable voltage in response to said desirable parameter, whereby said power sharing operation for said one power supply unit is achieved independently of other power sharing operations for other power supply units. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11)
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12. A power inverting method capable of parallel-connecting a plurality of power supply units to a common bus line, comprising the steps of:
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entering a plurality of input commands for changing an amplitude of an AC (alternating current) output voltage of a power inverter employed in one power supply unit; detecting a variation in an AC output current of said one power supply unit when the amplitude of said AC output voltage of said power inverter is changed; processing said variation in the AC output current to infer a desirable parameter required to share AC power which should be derived from said one power supply unit with respect to total output power capable of being supplied from said common bus line to a load; and controlling said one power supply unit to output a desirable voltage in response to said desirable parameter, whereby said power sharing operation for said one power supply unit is achieved independently of other power sharing operations for other power supply units.
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13. A power inverting method capable of parallel-connecting a plurality of power supply units to a common bus line, comprising the steps of:
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entering a plurality of input commands for changing a phase angle of an AC (alternating current) output voltage of a power inverter employed in one power supply unit; detecting a variation in an AC output current of said one power supply unit when the phase of said AC output voltage of said power inverter is changed; processing said variation in the AC output current to infer a desirable parameter required to share AC power which should be derived from said one power supply unit with respect to total output power capable of being supplied from said common bus line to a load; and controlling said one power supply unit to output a desirable voltage in response to said desirable parameter, whereby said power sharing operation for said one power supply unit is achieved independently of other power sharing operations for other power supply units.
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Specification