Acoustic transducer driver and controller
An acoustophoretic system is controlled and driven to attain a desired level of performance. An RF controller and a driver provide a frequency and power to an acoustic transducer, which can be implemented as a piezoelectric element, which presents a reactive load or a complex load. 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 system to produce a modal pattern and to provide efficient operation of the transducer. A method of detecting a minimum or maximum reactance in a acoustophoretic system used to trap, separate, deflect, cluster, fractionate or otherwise process particles or secondary fluids or tertiary fluids in a primary fluid and utilizing the frequency of the detected reactance to operate the acoustophoretic system.
1. A control system, comprising:
an electronic driver for driving a load that exhibits dynamic impedance;
a controller coupled to the electronic driver and to the load for controlling a frequency of a drive signal applied to the load, the controller being configured to control the frequency of the drive signal based on impedance determined from a feedback signal from the load; and
the controller being configured to determine a frequency associated with impedance minima or maxima of the load.
2. The system of claim 1 , wherein the impedance minima or maxima are reactance minima or maxima.
3. The system of claim 2 , wherein controller is configured to generate a control signal to cause the electronic driver to provide the drive signal to the load at the frequency associated with a reactance minimum or maximum.
4. The system of claim 1 , wherein the controller is configured to determine a reactance value for the load for at least some frequencies in a range of frequencies, such that a minimum or maximum reactance value is determined for the range of frequencies.
5. The system according to claim 4 , where in the controller is configured to identify a new frequency in the range of frequencies associated with the minimum or maximum reactance value so as to track changes in the frequency at which a minimum or a maximum reactance of the load occurs.
6. The system of claim 1 , wherein the load is an acoustic transducer.
7. The system of claim 1 , wherein the controller is configured to determine electrical power consumed by the load based on the feedback signals.
8. The system of claim 7 , wherein the controller is configured to control one or more of a voltage, a current or a frequency of the drive signal provided to the load to control electrical power consumed by the load.
9. The system of claim 1 , wherein the controller is configured to decompose the feedback signal into in-phase and quadrature-phase components.
10. The system of claim 9 , wherein the controller is configured to determine phase angle and reactance based on the in-phase and quadrature-phase components.
11. The system of claim 1 , further comprising pipelined analog-to-digital converters for sampling voltage and current of the load.
12. The system of claim 1 , wherein the controller is configured to initiate a frequency scan based on one or more of a timed interval or an event.
13. The system of claim 12 , wherein the controller is configured to receive parameters of the frequency scan that include one or more of a frequency range, a frequency step size or a frequency step time interval.
14. The system of claim 1 , further comprising a filter between the electronic driver and the load.
15. The system of claim 1 , wherein the electronic driver further comprises a DC converter and an RF inverter.
16. The system of claim 15 , further comprising a filter between the DC converter and the RF inverter.
17. A device for controlling a dynamic impedance load, comprising:
a controller for implementing a control scheme;
a power section connected to the controller for supplying power to the load; and
a feedback section interposed between the load and the controller to provide feedback to the controller for operating parameters of the load;
wherein the control scheme includes controlling power supplied to the load based on impedance determined from the feedback; and
the controller being configured to determine a frequency associated with impedance minima or maxima of the load.
18. The device of claim 17 , wherein the control scheme further comprises controlling a frequency of the power supplied to the load to track a minimum or maximum reactance of the load.
19. The device of claim 18 , wherein the control scheme further comprises adjusting a frequency sweep range in which the minimum or maximum reactance of the load is expected.