Temperature control in ultrasonic surgical instruments

A surgical system, comprising:

• a surgical instrument comprising an ultrasonic drive system that includes an ultrasonic blade and an ultrasonic transducer energizable to drive the ultrasonic blade;
• a temperature sensor to sense a temperature of the ultrasonic transducer;
• and
• a controller in operable communication with the ultrasonic transducer and the temperature sensor, the controller being operable to:
• receive a user input;
• set a temperature set point of the ultrasonic blade based on the user input;
• drive, with the ultrasonic transducer, the ultrasonic blade in a first manner;
• sense, with the temperature sensor, the temperature of the ultrasonic transducer;
• determine the natural frequency of the ultrasonic drive system;
• determine a temperature of the ultrasonic blade based on the natural frequency and the temperature of the ultrasonic transducer;
• compare the temperature of the ultrasonic blade to the temperature set point;
• and
• drive, with the ultrasonic transducer, the ultrasonic blade in a second manner different than the first manner based on the comparison.

A surgical system, comprising:

• an ultrasonic drive system that includes an ultrasonic blade and an ultrasonic transducer energizable to drive the ultrasonic blade;
• a temperature sensor to sense a temperature of the ultrasonic transducer;
• and
• a controller in operable communication with the ultrasonic transducer and the temperature sensor, the controller being operable to:
• drive, with the ultrasonic transducer, the ultrasonic blade in a first manner;
• sense, with the temperature sensor, the temperature of the ultrasonic transducer;
• estimate a temperature of the ultrasonic blade based on a natural frequency of the ultrasonic drive system and the temperature of the ultrasonic transducer;
• compare the temperature of the ultrasonic blade to a temperature range;
• and
• drive, with the ultrasonic transducer, the ultrasonic blade in a second manner different than the first manner based on the comparison.