Method and apparatus for controlling a temperature-controlled probe

A method of controlling a power output to a probe, the method comprising:

• (a) providing in a memory at least one set of settings for said probe including at least one gain parameter and corresponding predetermined operating characteristics for said probe;
• (b) receiving a target probe temperature;
• (c) receiving a first probe setting corresponding to a desired set of operating characteristics for said probe;
• (d) selecting from said at least one set of probe settings a set of settings in response to said first probe setting;
• (e) generating an error signal e(t) from a comparison of a sensed temperature sensed by a probe temperature sensor and said target probe temperature;
• (f) providing a controller with a control function that examines a rate at which said sensed temperature approaches said target temperature, and determines whether said sensed temperature will attain but not exceed said target temperature;
• (g) using said error signal e(t) to dynamically control at least one factor of said control function to determine an output power control signal;
• and
• (h) controlling the power output to a probe thermal element responsive to said output power control signal.

A system to control a power output to a probe having a probe thermal element and a probe temperature sensor such that a target probe temperature is maintained at the probe without substantial overshoot, the system comprising:

• a controller including a processor and memory, said memory including at least one set of settings for said probe, including at least one gain parameter and corresponding predetermined operating characteristics for said probe, and further including a routine executable by said processor to cause said processor to carry out the following:
• (a) to receive said target probe temperature;
• (b) to receive a first probe setting corresponding to a desired set of operating characteristics for said probe;
• (c) to select from said at least one set of probe settings a set of settings in response to said first probe setting;
• (d) to generate an error signal e(t) from a comparison of a sensed temperature sensed by said sensor and said target probe temperature;
• (e) to provide said controller with a control function that examines a rate at which temperature approaches said target probe temperature, and determines whether said sensed temperature will attain but not exceed said target temperature;
• (f) to use said error signal e(t) to dynamically control at least one factor of said control function to determine an output power control signal;
• and
• (g) to control the power output to said thermal element responsive to said output power control signal.

A computer readable medium comprising:

• software for execution by a computer processor to control a power output to a probe having a probe thermal element and a probe temperature sensor, and
• a memory including at least one set of settings for said probe including at least one gain parameter and corresponding predetermined operating characteristics for said probe,
• said software carrying out the following
• (a) receiving said target probe temperature;
• (b) receiving a first probe setting corresponding to a desired set of operating characteristics for said probe;
• (c) selecting from said at least one set of probe settings a set of settings in response to said first probe setting;
• (d) generating an error signal e(t) from a comparison of a sensed temperature sensed by said sensor and said target temperature;
• (e) providing a control function for generating an output power control signal, said control function comprising a first mode wherein said output power control signal comprises a constant power, and a second mode wherein said output power control signal is generated based on an examination of a rate at which said sensed temperature approaches said target temperature and a determination of whether said sensed temperature will attain but not exceed said target temperature;
• (f) using said error signal e(t) to dynamically control at least one factor of said control function to determine said output power control signal;
• and
• (g) controlling power output to said thermal element responsive to said power output control signal.

A method comprising:

• receiving a gain factor corresponding to an electrosurgical instrument;
• receiving a target temperature;
• receiving a sensed temperature;
• and
• generating a power signal from a control function operating on the target temperature, the sensed temperature, and the gain factor.

A method comprising:

• choosing proportional, derivative, and integral gain factors corresponding to an electrosurgical instrument;
• receiving a target temperature;
• receiving a sensed temperature;
• generating an error signal based on a comparison of the sensed temperature with the target temperature;
• generating a power signal from a control function operating on a proportional signal based on a product of the error signal and the proportional gain factor, a derivative signal based on a product of the derivative gain factor and a derivative of at least one of the error signal and the sensed temperature, and an integral signal based on a product of the integral gain factor and an integral of the error signal;
• and
• providing the power signal to the electrosurgical instrument.

A method comprising:

• receiving a target temperature;
• receiving a sensed temperature;
• generating an error signal based on a comparison of the sensed temperature and the target temperature;
• receiving a parameter for a control function for generating a power signal for an electrosurgical instrument;
• and
• replacing the parameter for the control function with a second parameter for the control function based on a comparison of the error signal and a threshold value.

A method comprising:

• receiving a target temperature;
• receiving a sensed temperature;
• generating an error signal based on a comparison of the sensed temperature and the target temperature;
• choosing proportional, integral, and derivative gain factors, based on a comparison of the error signal and a first threshold value;
• replacing original gain factors in a control function for generating a power signal for an electrosurgical instrument with the proportional gain factor, the integral gain factor, and the derivative gain factor;
• generating the power signal with the control function including generating a proportional signal based on a product of the error signal and the proportional gain factor, generating an integral signal based on a product of the integral gain factor and an integral of the error signal, generating a derivative signal based on a product of the derivative gain factor and a derivative of at least one of the error signal and the sensed temperature, and combining the proportional signal, the integral signal and the derivative signal;
• and
• switching the power signal to a maximum power based on a comparison of the error signal and a second threshold value.

A device comprising:

• means for receiving a target temperature;
• means for receiving a sensed temperature;
• means for generating an error signal based on a comparison of the sensed temperature and the target temperature;
• means for receiving a parameter for a control function for generating a power signal for an electrosurgical instrument and
• means for replacing the parameter for the control function with a second parameter for the control function based on a comparison of the error signal and a threshold value.

A device comprising:

• means for receiving a target temperature;
• means for receiving a sensed temperature;
• means for generating an error signal based on a comparison of the sensed temperature and the target temperature;
• means for choosing proportional, integral, and derivative gain factors, based on a comparison of the error signal and a first threshold value;
• means for replacing original gain factors in a control function for generating a power signal for an electrosurgical instrument with the proportional gain factor, the integral gain factor, and the derivative gain factor;
• means for generating the power signal with the control function comprising means for generating a proportional signal based on a product of the error signal and the proportional gain factor, means for generating an integral signal based on a product of the integral gain factor and an integral of the error signal, means for generating a derivative signal based on a product of the derivative gain factor and a derivative of at least one of the error signal and the sensed temperature, and means for combining the proportional signal, the integral signal and the derivative signal;
• and
• means for switching the power signal to a maximum power based on a comparison of the error signal and a second threshold value.

A device comprising:

• a first input component configured to receive a sensed temperature;
• a second input component configured to receive a target temperature;
• a third input component configured to receive a gain factor corresponding to an electrosurgical instrument;
• a power control circuit coupled to the first input component, the second input component, and the third input component, the power control circuit operable on the sensed temperature, the target temperature, and the gain factor and configured to generate a power signal for the electrosurgical instrument.