A static inverter with a relatively low-frequency output voltage, and a method for generating this voltage

摘要

in a static inverter for providing a low-frequency output (e.g. 60Hz) from a d.c. supply (Q), the passage of low-frequency currents through the inverter transformer (P) is avoided by producing a train of high-frequency pulses (e.g. 40kHz) which represent, for example by their pulse widths (4), the successive instantaneous amplitudes of the required low-frequency voltage. These pulses cause a train of corresponding pulses (7) to be produced at the secondary of the transformer, and this train is filtered (H) to produce a unidirectional voltage (9) having the desired instantaneous amplitudes. This voltage is fed to a transistor switching bridge (1) which changes the unidirectional voltage into an alternating voltage (12) having the required low-frequency. Means (N, E, L, M) is preferably provided to allow regeneration of power from the load back into the d.c. supply (Q).