Abstract: The operation of an interior permanent magnet synchronous motor is extended to the constant horsepower regime by causing the stator current vector to follow the voltage-limit ellipse in the counter-clockwise direction. The error between commanded stator current and actual stator current is determined to signal a saturation of the inverter and the commanded stator current is modified to reduce the error.

Abstract: By using the on-state forward voltage drops of the power switches to measure phase currents, and by using diode logic to sense the voltage drops, it is possible for a single voltage comparator to perform the current regulation function for an entire power converter. Current regulation is obtained in drives using either overlapping or nonoverlapping current conduction for excitation of the motor phases. A thermistor compensates for offsets and for temperature sensitivity of the power switch voltage drops.

Abstract: A circuit for operating an electric discharge lamp comprises an inductor in series with the lamp, a capacitor in parallel with the lamp, and a transistorized inverter circuit connected in series with the inductor and the lamp. The operating frequency of the inverter increases with increasing load. A harmonic of the inverter output frequency is initially established at the resonant frequency of the inductor and capacitor to produce a high open circuit lamp starting voltage. Upon establishment of an electrical discharge in the lamp, the inverter frequency increases to provide efficient, stable lamp operation.