Oil pressure unit and speed control method of motor in oil pressure unit

Abstract

An oil pressure unit includes an inverter arranged to supply electric power to a motor; a load sensor arranged to detect a load of the oil pressure pump; a rotation sensor arranged to detect a rotation speed of the motor; a current command value calculation part configured to calculate a current command value so that a deviation between a speed command value representing a target rotation speed of the motor and a rotation speed of the motor converges to zero; a correction part configured to correct the current command value based on the load of the oil pressure pump; and a control signal generation part configured to output a control signal to the inverter based on a corrected current command value.

1 . An oil pressure unit for supplying oil to an actuator by driving an oil pressure pump with a motor, the oil pressure unit comprising:
 an inverter arranged to supply electric power to the motor;   a load sensor arranged to detect a load of the oil pressure pump;   a rotation sensor arranged to detect a rotation speed of the motor;   a current command value calculation part configured to calculate a current command value so that a deviation between a speed command value representing a target rotation speed of the motor and a rotation speed of the motor converges to zero;   a correction part configured to correct the current command value based on the load of the oil pressure pump; and   a control signal generation part configured to output control signal to the inverter based on a corrected current command value.   
   
   
       2 . The oil pressure unit according to  claim 1 , wherein
 the correction part corrects the current command value to raise the rotation speed of the motor with an increase in the load of the oil pressure pump.   
   
   
       3 . The oil pressure unit according to  claim 1 , wherein
 the correction part increases the current command value in response to an increase in the load of the oil pressure pump.   
   
   
       4 . The oil pressure unit according to  claim 1 , wherein
 the correction part acquires a correction value using a correction coefficient set in advance, and adds the correction value to the current command value.   
   
   
       5 . The oil pressure unit according to  claim 3 , wherein
 the correction part acquires a correction value using a correction coefficient set in advance, and adds the correction value to the current command value.   
   
   
       6 . The oil pressure unit according to  claim 1 , wherein
 the correction part acquires a correction value using a data table DT acquired in advance, and adds the correction value to the current command value.   
   
   
       7 . The oil pressure unit according to  claim 3 , wherein
 the correction part acquires a correction value using a data table DT acquired in advance, and adds the correction value to the current command value.   
   
   
       8 . The oil pressure unit according to  claim 1 , wherein
 the load sensor is a pressure sensor arranged to detect a pressure of oil in a discharge line of the oil pressure pump.   
   
   
       9 . The oil pressure unit according to  claim 3 , wherein
 the load sensor is a pressure sensor arranged to detect a pressure of oil in a discharge line of the oil pressure pump.   
   
   
       10 . The oil pressure unit according to  claim 4 , wherein
 the load sensor is a pressure sensor arranged to detect a pressure of oil in a discharge line of the oil pressure pump.   
   
   
       11 . The oil pressure unit according to  claim 5 , wherein
 the load sensor is a pressure sensor arranged to detect a pressure of oil in a discharge line of the oil pressure pump.   
   
   
       12 . The oil pressure unit according to  claim 6 , wherein
 the load sensor is a pressure sensor arranged to detect a pressure of oil in a discharge line of the oil pressure pump.   
   
   
       13 . A speed control method of a motor in an oil pressure unit for supplying oil to an actuator by driving an oil pressure pump with the motor, which is controlled by an inverter comprising:
 detecting a load of the oil pressure pump;   detecting a rotation speed of the motor;   calculating a current command value so that a deviation between a speed command value representing a target rotation speed of the motor and a rotation speed of the motor converges to zero;   correcting the current command value based on the load of the oil pressure pump; and   outputting a control signal to the inverter based on a corrected current command value.   
   
   
       14 . The oil pressure unit according to  claim 2 , wherein
 the correction part increases the current command value in response to an increase in the load of the oil pressure pump.   
   
   
       15 . The oil pressure unit according to  claim 2 , wherein
 the correction part acquires a correction value using a correction coefficient set in advance, and adds the correction value to the current command value.   
   
   
       16 . The oil pressure unit according to  claim 2 , wherein
 the correction part acquires a correction value using a data table acquired in advance, and adds the correction value to the current command value.   
   
   
       17 . The oil pressure unit according to  claim 2 , wherein
 the load sensor is a pressure sensor arranged to detect a pressure of oil in a discharge line of the oil pressure pump.   
   
   
       18 . The oil pressure unit according to  claim 7 , wherein
 the load sensor is a pressure sensor arranged to detect a pressure of oil in a discharge line of the oil pressure pump.