A Stirling engine-equipped cogeneration system is capable of utilizing thermal energy, without waste, and of offering high thermal usage efficiency at every stage of the thermal energy utilization process. The coil has a first polarity state and a second polarity state. The method including operating the motor at a first substantially constant torque level, varying the static pressure of the system, receiving a torque selection signal from external to the motor, and operating the motor at a second substantially constant torque level, the level corresponding to the torque selection signal. The combination of the modulation scheme and spread spectrum high frequency behavior allows the user to eliminate the external filter.