Wide speed range electric power generation system using high reactance permanent magnet machine

A variable speed permanent magnet machine connected to a load comprising:

• a permanent magnet rotor;
• a stator assembly mounted adjacent said rotor and including a plurality of electrical windings disposed in a plurality of slots between a plurality of stator teeth and having a stator winding resistance RS, said electrical windings being electrically connected to a permanent magnet machine output adapted to deliver generated output voltage from said permanent magnet machine;
• a voltage control circuit providing a boost in said output voltage in a first rotational speed range, said voltage control circuit also providing limiting of output current to a pre-selected value in a second rotational speed range;
• wherein, in use, movement of said rotor induces a first alternating voltage and current in said electrical windings of a first polarity, said first alternating voltage and current inducing a second alternating voltage and current of a second polarity in said electrical windings;
• and
• said voltage control circuit limiting of output current being provided by said second alternating voltage and current of a second polarity.

A method for controlling a wide speed range high reactance permanent magnet machine in a plurality of speed ranges comprising:

• determining an output voltage across output terminals of a circuit including a wide speed range high reactance permanent magnet machine having stator windings, a diode bridge connected across said stator windings, a solid state switch connected across said diode bridge and a PWM controller circuit connected to the solid state switch;
• if said wide speed range high reactance permanent magnet machine is in a low speed range, and said detected output voltage is lower than a desired output voltage, increasing the duty cycle of said PWM controller to increase the detected output voltage;
• and
• if said wide speed range high reactance permanent magnet machine is in said low speed range, and said detected output voltage is higher than said desired voltage, decreasing the duty cycle of said PWM controller to decrease said detected output voltage.