Systems and methods for power management in ultrasonic sensors

1. A method of controlling energy of sound waves generated in a fluid sensing system, the method comprising:

generating, with a transducer, a first sound wave and a second sound wave in a tank having a fluid;

receiving, with the transducer, a first echo of the first sound wave and a first echo of the second sound wave;

comparing, with a controller, a signal characteristic of the first echo of the first and second sound waves; and

driving, with a driver, the transducer based on comparing the signal characteristic of the first echo of the first and second sound waves and to reduce a difference in amplitude of the first echo of the first and the second sound waves.

2. The method of claim 1 , further comprising:

comparing, with the controller, the signal characteristic of the first echo of the first and second sound waves to a predetermined threshold.

3. The method of claim 2 , wherein comparing the signal characteristic of the first echo of the first and second sound waves includes comparing a phase error of the first echo of the first and second sound waves with the predetermined threshold.

4. The method of claim 1 , wherein the signal characteristic is selected from the group consisting of an amplitude, a phase, and a lobe shift.

5. The method of claim 1 , wherein driving the transducer includes changing an output power of the transducer and generating a third sound wave based on comparing amplitudes of the first echo of the first and the second sound waves to the predetermined threshold.

6. The method of claim 5 , wherein driving the transducer includes changing an output power of the transducer to generate not more than two echoes of the second sound wave.

7. The method of claim 1 , wherein generating the second sound wave includes determining a power of the first sound wave at which an amplitude of a lobe of the first echo of the first sound wave falls below a threshold.

8. A fluid sensing system, the system comprising:

a transducer configured to generate a first sound wave and a second sound wave and to detect a first echo of the first and second sound waves;

a driver configured to drive the transducer to produce the first and second sound waves; and

a controller configured to

compare a signal characteristic of the first echo of the first and second sound waves, and

control the driver based on comparing the signal characteristic of the first echo of the first and second sound waves, in order to reduce a difference in amplitude of the first echo of the first and second sound waves.

9. The fluid sensing system of claim 8 , wherein the signal characteristic is selected from the group consisting of amplitude, phase and lobe shift.

10. The fluid sensing system of claim 9 , wherein the driver is configured to change an output power of the transducer and generate a third sound wave based on the amplitude of the first echo of the first and second sound waves.

11. The fluid sensing system of claim 10 , wherein the output power of the transducer is configured to generate not more than two echoes of the first and second sound waves.

12. The fluid sensing system of claim 8 , wherein the controller is configured to compare the signal characteristic of the first echo of the first and second sound waves to a predetermined threshold.

13. The fluid sensing system of claim 12 , wherein the controller is configured to determine a power of the first sound wave at which the amplitude of a lobe of the first echo is equal to the predetermined threshold.

14. The fluid sensing system of claim 12 , wherein a phase error of the first echo of the first and second sound waves is within the predetermined threshold.

15. A system for controlling energy of sound waves generated for fluid sensing, the system comprising:

a controller comprising a memory and an electronic processor executing computer-readable instructions that cause the system to:

generate a first sound wave and a second sound wave in a tank having a fluid;

receive a first echo of the first sound wave and a first echo of the second sound wave;

compare a signal characteristic of the first echo of the first and second sound waves;

drive a transducer based on comparing the signal characteristic of the first echo of the first and second sound waves; and

reduce a difference in amplitude of the first echo of the first and the second sound waves.