Abstract: A compression sense ignition system includes a sensing capacitor having a conductive sensing element disposed in proximity to the secondary winding leads of a first and a second ignition coil for developing a compression sense ignition signal. Epoxy potting material encapsulates the leads and the sensing element to reduce variation of the effective capacitance of the sensing capacitor. The compression sense ignition signal is processed to generate a cylinder identification signal which is used to determine absolute engine position. A fault mode detection and correction scheme is implemented wherein a controller responsive to the cylinder identification signal can determine correct absolute engine position notwithstanding the occurrence of one or more engine or ignition system faults which may impair the cylinder identification signal.

Abstract: A speed sensorless hybrid vector control starts from zero speed by using indirect vector control with stator frequency equal to slip frequency. As soon as the rotor begins to rotate, the drive is converted to direct vector control for normal operation. The direct vector control uses several low pass filters. The first is a harmonic reducing filter for the sensed motor phase current and voltage signals. The others comprise integration apparatus used in the calculation of motor flux quantities from the motor phase current and voltage signals.