Control method for direct-current by means of a plurality of converters
First Claim
1. In a power distribution and transmission system, a method for controlling at least three converters that can be controlled as rectifiers or as inverters and that are connected to one another via a DC power supply system, the method which comprises:
- measuring a respective measured DC voltage and a respective measured direct current at each converter and transmitting to a rectifier control system in order to control the respective rectifier, or to an inverter control system in order to control a respectively associated inverter;
defining a respectively associated rectifier nominal DC power and a respective inverter nominal DC power for each rectifier control system and for each inverter control system, with a sum of all the rectifier nominal DC powers and all the inverter nominal DC powers being equal to zero;
determining a respectively associated inverter nominal DC voltage from each inverter nominal DC power;
defining a lowest inverter nominal DC voltage of all the inverters connected to the DC power supply system as a minimum DC voltage;
respectively calculating a rectifier nominal direct current and an inverter nominal direct current by way of the minimum DC voltage from each rectifier nominal DC power and from each inverter nominal DC power;
with each rectifier control system, forming a difference between the minimum DC voltage and the respectively received rectifier measured DC voltage, resulting in a rectifier difference DC voltage, and forming a difference between the respective rectifier nominal current and the respectively received rectifier measured direct current, resulting in a rectifier difference direct current, and controlling the associated rectifier to minimize a sum of the difference DC voltage and the difference direct current; and
with each inverter control system, forming a difference between the minimum DC voltage and the respectively received inverter measured DC voltage, resulting in an inverter difference DC voltage, and forming a difference between the respective inverter nominal current and the respectively received inverter measured direct current, resulting in an inverter difference direct current, and controlling the respectively associated inverter to minimize a difference between the inverter difference direct current and the inverter difference DC voltage.
1 Assignment
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Accused Products
Abstract
At least three power converters in a power distribution and power transmission system can be controlled as rectifiers or inverters and are connected together by a direct current network. A measuring direct current voltage and a measuring direct current are measured on each power converter and respectively, transmitted to the respective rectifier control and/or inverter control, and a rectifier desired direct power and/or inverter desired direct power is determined for each power converter. The total of all desired direct powers is equal to zero, and a desired direct voltage is determined from each desired direct power, the smallest inverter desired direct voltage of all connected inverters is fixed as minimal direct voltage by means of a minimal direct voltage and the desired direct voltage, a desired direct current is formed from the minimal voltage and the measuring direct voltage, a differential direct voltage is formed from the minimal voltage and the differential direct current is formed from the desired direct current and the measuring direct current. The respective rectifier control of the rectifier is controlled to minimize the total of the differential direct voltage and the differential direct current, and the inverter control of the inverter is controlled to minimize the difference between the differential direct current and the differential direct voltage.
7 Citations
9 Claims
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1. In a power distribution and transmission system, a method for controlling at least three converters that can be controlled as rectifiers or as inverters and that are connected to one another via a DC power supply system, the method which comprises:
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measuring a respective measured DC voltage and a respective measured direct current at each converter and transmitting to a rectifier control system in order to control the respective rectifier, or to an inverter control system in order to control a respectively associated inverter; defining a respectively associated rectifier nominal DC power and a respective inverter nominal DC power for each rectifier control system and for each inverter control system, with a sum of all the rectifier nominal DC powers and all the inverter nominal DC powers being equal to zero; determining a respectively associated inverter nominal DC voltage from each inverter nominal DC power; defining a lowest inverter nominal DC voltage of all the inverters connected to the DC power supply system as a minimum DC voltage; respectively calculating a rectifier nominal direct current and an inverter nominal direct current by way of the minimum DC voltage from each rectifier nominal DC power and from each inverter nominal DC power; with each rectifier control system, forming a difference between the minimum DC voltage and the respectively received rectifier measured DC voltage, resulting in a rectifier difference DC voltage, and forming a difference between the respective rectifier nominal current and the respectively received rectifier measured direct current, resulting in a rectifier difference direct current, and controlling the associated rectifier to minimize a sum of the difference DC voltage and the difference direct current; and with each inverter control system, forming a difference between the minimum DC voltage and the respectively received inverter measured DC voltage, resulting in an inverter difference DC voltage, and forming a difference between the respective inverter nominal current and the respectively received inverter measured direct current, resulting in an inverter difference direct current, and controlling the respectively associated inverter to minimize a difference between the inverter difference direct current and the inverter difference DC voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification