| 摘要 |
A switched multi-tapped transformer-based power conversion circuit is disclosed. A polarity alternator comprising dual switch devices controlled by a microprocessor selectively periodically impresses across a transformer's center-tapped primary winding a voltage from a battery to produce a modified square waveform. Each of the taps of the transformer's secondary winding synchronously selectively switched by the microprocessor to a common wired-OR junction where the discrete voltage levels combine to produce a stepped approximation of a stored sine waveform. The switching circuits for each of the taps comprises dual back-to-back series-connected FET switches with diodes shunting each FET's source and drain. The microprocessor periodically senses the voltage across the primary winding, calculates the voltage across the secondary winding based upon the predetermined turns ratio of the tap that is switched to the common junction and compares the calculated output voltage with a normalized memory-based sine wave representation, thereby to determine when to switch to another tap. The converter, which operates concurrently as an inverter and a charger, responds in real time to changing DC source and AC load conditions. A similar converter having a full-wave rectifier on the primary winding side of the transformer is connectable to an AC source and provides for the charging of a connected DC load.
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