Closed loop resonance tracking using phase matching
AssigneeTexas Instruments Incorporated
InventorsSupriyo Palit, David Hernandez
Life of this patent
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Abstract
Disclosed embodiments include a method for closed loop phase tracking comprised of determining a first estimated resonant frequency, generating a motor drive signal at the first estimated resonant frequency and applying the motor drive signal to a motor, measuring current and voltage of the motor drive signal, and filtering the measurements of current and voltage of the motor drive signal. The phase difference between the filtered current and voltage waveforms is measured and a second estimated resonant frequency is calculated. The generated motor drive frequency is adjusted to equal the second estimated resonant frequency.
Claims22
A method for closed loop phase tracking comprised of:
- determining a first estimated resonant frequency;
- generating a motor drive signal at the first estimated resonant frequency and applying the motor drive signal to a motor;
- measuring current and voltage of the motor drive signal;
- filtering the measurements of current and voltage;
- measuring the phase difference between the filtered current and voltage;
- and
- calculating a second estimated resonant frequency and adjusting the generated motor drive frequency to equal the second estimated resonant frequency.
An apparatus for closed loop control of a linear resonant actuator comprising:
- a motor drive circuit that generates a motor drive signal having a frequency of a first resonant frequency and configured to provide the motor drive signal to a motor;
- a current and voltage sensing circuit configured to couple to a motor and measure current and voltage from the motor drive signal;
- a noise filter circuit coupled to the current and voltage sensing circuit that filters noise from the current and voltage measurements;
- a phase measurement circuit coupled to the noise filter circuit configured to receive the filtered current and voltage measurements as inputs and to output phase measurements of the current and voltage and a difference in phase between the current and voltage measurements;
- and
- a resonant frequency tracking circuit coupled to the phase measurement circuit configured to receive as inputs the phase measurements of the current and voltage and the difference in phase, calculate a second resonant frequency, and output to the motor drive circuit a frequency command corresponding to the second resonant frequency.
A system for closed loop control of a linear resonant actuator comprising:
- a motor drive circuit configured to generate a motor drive signal having a frequency of a first resonant frequency;
- a current and voltage sensing circuit configured to measure current and voltage from the motor drive signal;
- a noise filter circuit configured to receive the current and voltage measurements and to filter noise from the current and voltage measurements;
- a phase measurement circuit configured to receive the filtered current and voltage measurements and to output phase measurements of the current and voltage and a difference in phase between the current and voltage measurements;
- and
- a resonant frequency tracking circuit configured to receive the phase measurements of the current and voltage and the difference in phase, calculate a second resonant frequency, and output to the motor drive circuit a frequency command corresponding to the second resonant frequency.
Dependencies are inferred from the claim text.