ACOUSTIC TRANSDUCER CONTROLLER CONFIGURATION
An RF driver provides power to an acoustic transducer, which can be implemented as a piezoelectric element, which presents a reactive load. The driver can be a linear amplifier or a combination of a DC-DC converter and DC-AC inverter. A controller implements a control technique for efficient transducer operation. The control technique can locate a frequency for operation that is at a reactance minimum or maximum for the transducer to provide efficient operation of that transducer. An implementation of the controller can be provided in modular hardware.
1 . An acoustophoresis system, comprising:
a chamber for receiving a fluid mixture that includes cells or particles in a fluid;
an ultrasonic transducer coupled to the chamber and configured to be excited to generate an acoustic wave in the chamber,
a driver electrically connected to the ultrasonic transducer and configured to provide an excitation to the ultrasonic transducer to generate the acoustic wave in the chamber; and
a controller electrically connected to the driver and the ultrasonic transducer and configured to receive feedback signals from the ultrasonic transducer and to control the driver.
2 . The system of claim 1 , wherein the ultrasonic transducer comprises a plurality of transducers, each of the plurality of transducers being electrically connected to a distinct driver.
3 . The system of claim 1 , wherein the driver further comprises a DC converter and an RF inverter.
4 . The system of claim 1 , further comprising a capacitor electrically connected between the driver and the ultrasonic transducer.
5 . The system of claim 1 , further comprising a power resistor electrically connected between the driver and the ultrasonic transducer.
6 . The system of claim 1 , further comprising the controller being configured to determine frequencies where anti-resonance, and reactance minima and maxima occur based on the feedback signals.
7 . The system of claim 1 , further comprising the controller being configured to select a frequency associated with a reactance minimum or maximum based on the feedback signals.
8 . A method for controlling an acoustic transducer, comprising:
determining an anti-resonance frequency of the acoustic transducer;
determining a reactance minimum or maximum adjacent to the anti-resonance frequency; and
providing a power signal to the acoustic transducer with the frequency substantially of the reactance minimum or maximum.
9 . The method according to claim 8 , further comprising:
scanning a frequency range for a new reactance minimum or maximum; and
adjusting the frequency of the power signal to a new frequency associated with the new reactance minimum or maximum.
10 . The method of claim 8 , further comprising:
receiving feedback signals from the acoustic transducer; and
determining an electrical power consumed by the acoustic transducer based on the feedback signals.
11 . The method of claim 10 , further comprising controlling one or more of a voltage, a current or a frequency of the power signal provided to the acoustic transducer to control electrical power consumed by the acoustic transducer.
12 . The method of claim 8 , further comprising:
receiving feedback signals from the acoustic transducer; and
decomposing the feedback signals into in-phase and quadrature-phase components.
13 . The method of claim 12 , further comprising determining phase angle and reactance based on the in-phase and quadrature-phase components.
14 . The method of claim 8 , further comprising sampling voltage and current of the acoustic transducer with pipelined analog-to-digital converters.
15 . The method of claim 8 , further comprising initiating a frequency scan based on one or more of a timed interval or an event.
16 . The method of claim 15 , further comprising receiving parameters of the frequency scan that include one or more of a frequency range, a frequency step size or a frequency step time interval.
17 . The method of claim 8 , further comprising determining the phase angle of the impedance of the ultrasonic transducer.
18 . A device for controlling an acoustic transducer, comprising:
a modular controller for implementing a control scheme;
a power section connected to the controller for supplying power to the acoustic transducer, and
a feedback section interposed between the acoustic transducer and the controller to provide feedback to the controller for the operating parameters of the acoustic transducer.
19 . The device of claim 18 , wherein the power section further comprises a power converter and an RF inverter.
20 . The device of claim 18 , wherein the controller further comprises a processing engine configured to receive feedback signals, determine a minimum or maximum reactance from the feedback signals, and provide control signals to the power section to control one or more of voltage, current, or frequency of an output of the power section.