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AssigneesThomson-CSF, Semikron International
InventorsAlain Levy, Ernst Schimanek, Wolfram Dietze
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Disclosed is a dc/ac inverter for the supply of alternating current to the windings of a synchronous electrical motor, especially for the traction of an electrical vehicle. During each half-wave of the alternating current, the dc/ac inverter with solid-state switches delivers steady levels of constant intensity. During each steady level, the intensity of the current is determined by the cyclical ratio of a chopping signal that controls the conduction of the transistor-based or thyristor-based switches. At zero speed of the rotor, the frequency f of the chopping signal has a value (f', 1 khz) smaller than the chopping frequency (8 kHz) for a speed different from zero. Thus the starting losses or the losses with the rotor off are minimized.
A dc/ac inverter for supplying alternating current to a stator of a rotating-field electrical motor, said dc/ac inverter comprising solid-state controlled switches delivering alternating currents to the stator, the intensity of each of the alternating currents, in the course of each half-wave, having successive sequences during each of which the intensity is substantially constant and determined by a cyclical ratio of a chopping signal controlling a conduction of each of the switches, wherein said inverter further comprises a means to give a frequency f of the chopping signal, a value f' at zero rotation speed of the rotor that is smaller than the chopping frequency for a rotation speed of the rotor that is different from zero.
Dependencies are inferred from the claim text.