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Control method for direct-current by means of a plurality of converters

  • US 7,729,142 B2
  • Filed: 09/22/2005
  • Issued: 06/01/2010
  • Est. Priority Date: 09/22/2005
  • Status: Expired due to Fees
First Claim
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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:

  • 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.

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