Patent ID: 6883333

Claim:
A method for sensorlessly controlling the operation of a thermoacoustic device including a linear electrodynamic machine communicating with a load device, said method comprising the steps of: providing a thermoacoustic device including a linear electrodynamic machine communicating with a load device through a piston; setting electrical inputs to the electrodynamic machine, the electrical inputs including frequency and either voltage or current; determining a voltage signal at an input of the electrodynamic machine; determining a current signal at the input of the electrodynamic machine; estimating a positional parameter of the piston using the voltage and current signals, the positional parameter being selected from the group consisting of displacement, velocity, and acceleration of the piston; estimating a force parameter of the load device using the positional parameter and the current signal, the force parameter being selected from the group consisting of force and pressure on the piston; using the positional parameter and the force parameter to determine at least one operating condition of the thermoacoustic device, the operating condition being the phase angle between the positional parameter and the force parameter; determining a difference between the at least one operating condition and a desired operating condition; and adjusting at least one electrical input to the electrodynamic machine so as to reduce the difference, the adjusted input being one of frequency, current, and voltage.