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Hybrid excavator and method of controlling hybrid excavator

  • US 9,441,345 B2
  • Filed: 04/14/2014
  • Issued: 09/13/2016
  • Est. Priority Date: 10/26/2011
  • Status: Expired due to Fees
First Claim
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1. A hybrid excavator comprising:

  • a lower running body;

    an upper turning body that is positioned on the lower running body;

    a boom including one end that is rotatably attached to the upper turning body;

    an engine that is positioned at the upper turning body;

    a motor generator that is positioned at the upper turning body and is configured to perform an assist operation for the engine and an electric power generating operation using the engine;

    a motor generator control part that is configured to control the motor generator in response to a switching control signal supplied from a control unit;

    a first electrical energy storage device that is positioned at the upper turning body;

    a second electrical energy storage device that is positioned at the upper turning body and is electrically connected to the motor generator control part;

    a charge/discharge control part that is positioned at the upper turning body and is configured to control a charge/discharge operation between the first electrical energy storage device and the second electrical energy storage device in response to an externally supplied control command signal;

    a motor that is positioned at the upper turning body and is electrically connected to the second electrical energy storage device, the motor being configured to perform a regeneration operation for generating electric energy from mechanical energy and store the electric energy generated by the regeneration operation in the second electrical energy storage device; and

    the control unit that is configured to supply a control signal to at least one of the motor generator control part and the charge/discharge control part;

    wherein the control unit is configured to set a second electrical energy storage target value for the second electrical energy storage device to a higher value than a first electrical energy storage target value for the first electrical energy storage device during the regeneration operation performed by the motor, andwherein, during a period in which the motor performs a power running operation, the control unit sets the second electrical energy storage target value for the second electrical energy storage device to a higher value than a previous electrical energy storage target value for the second electrical energy storage device that is set up before the motor performs the power running operation.

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