Patent ID: 7453241

Claim:
An electrical power generating source comprising a free piston Stirling engine, including a power piston, driving a linear alternator, the alternator having an alternator winding, the power source comprising: (a) a switching mode rectifier connecting the alternator winding to an electrical energy storage means and including a pulse width modulator for controlling the rectifier switching duty cycle; (b) a negative feedback control loop for controlling alternator current and having a command input connected to a summing junction and an output connected to the pulse width modulator for controlling the operational duty cycle of the switching mode rectifier, the current control loop having a feedback circuit comprising a current sensor connected to the alternator winding for sensing instantaneous alternator current and applying a current feedback signal to the summing junction of the current feedback control loop; and (c) a negative feedback control loop for controlling a voltage, V internal , which is the sum of the voltage induced on the alternator winding and the voltage across the lumped resistance of the alternator winding, the V internal control loop having a command input applied to a summing point and a feedback circuit including a sensor means connected as an input to a computing circuit, the current sensor also being connected as an input to the computing circuit, the computing circuit computing and applying a signal representing V internal to the feedback input of the summing point of the V internal control loop, the output of the V internal control loop being connected as the command input to the current feedback control loop.