Power converting apparatus

Claim 2

A power converting apparatus comprising a solar array provided with maximum power operating point tracking control; DC-AC inverting means for converting a DC output voltage from the solar array into AC having a controlled voltage and frequency, and supplies an output thereof to a load; a commercial power source which compensates an insufficient power when a generated power of the solar array is less than the consumed power of the load; rectifying means which converts an AC voltage supplied by the commercial power source into a DC output and supplies that output to said DC-AC inverting means; and regenerating means which regenerates a surplus power into the commercial power source when the generated power of the solar array exceeds the consumed power of the load.

Claim 3

A power converting apparatus in accordance with claim 1, wherein the rectifying means comprises a plurality of rectifying elements and the regenerating means comprises a plurality of semiconductor switching elements respectively connected in parallel to the plurality of rectifying elements, and a control circuit which controls the semiconductor switching elements so as to retain the output voltage of the rectifying means at a constant value.

Claim 4

A power converting apparatus in accordance with claim 2, wherein the control circuit comprises a DC voltage detector which detects fluctuations of the generated voltage of the solar array; an error amplifier which compares the detected signal outputted from the DC voltage detector and a DC reference voltage set in advance to produce output signals in three different states corresponding to the operated results; a multiplier which multiplies the output signal of the error amplifier and the AC voltage of the commercial power reduced to a suitable signal level; a hysteresis comparator which compares the output signal of the multiplier with the current flowing in and out of the rectifying means and transformed into a suitable signal level; a pulse forming circuit which delays the output signal of the hysteresis comparator by a prescribed time and isolation amplifier means which amplifies the signal outputted successively at a prescribed interval by the pulse forming circuit to successively turn ON and OFF respective semiconductor switching elements.

Claim 5

A power converting apparatus in accordance with claim 2, wherein the plurality of semiconductor switching elements are semi-conductor switching elements having self-quenching ability.

Claim 6

A power converting apparatus in accordance with claim 1, wherein the regenerating means comprises a first transformer which transforms the output voltage of the DC-AC inverting means into a suitable signal level; a second transformer which transform the output voltage of the commercial power into a suitable signal level; a synchronous detecting circuit which compares respective output voltage and frequencies of the DC-AC inverting means and the commercial power by respective output voltage of the first and second transformers; and a switch means operated by the output signals of the synchronous detecting circuit, outputted when respective output voltages and frequencies of the DC-AC inverting means and the commercial power are synchronized, to connect the output end of the DC-AC inverting means to the commercial power.