AC current source circuit for converting DC voltage into AC current

DETAILED DESCRIPTION The present invention has been developed to solve the various problems of the above described snubber circuits and DC current power source, and aims at making a smaller snubber circuit having a small capacity, and providing an AC current source circuit which is small, light in weight, efficient, and less expensive.
Another object of the present invention is to provide an AC current source circuit whose DC reactor is small in size and light in weight.
A further object of the present invention is to provide an AC current source circuit for suppressing the generation of a beat frequency in an output current.
The AC current source circuit according to the present invention includes a chopper circuit for converting a DC input voltage into a chopper voltage, an inverter including at least four switch elements, for generating an output AC current having a predetermined frequency based on the chopper voltage, and clamping snubber circuits each corresponding to the switch elements.
The snubber circuits release or discharge electric charges or voltages to the input terminals of the DC input voltage of the chopper circuit.
The chopper circuit may include two unit chopper circuits connected in series between input terminals for the DC input voltage of the chopper circuit.
Each of the two unit chopper circuits may include a capacitor and a switch element connected to the capacitor in parallel, and the two capacitors may be connected in series between the input terminals of the DC input voltage.
The chopper circuit and the inverter are connected through a DC reactor (or a coil), and the DC input voltage is converted into a DC current by the chopper circuit and the DC reactor.
The inverter can be an n-phase full-bridge semiconductor current-fed (current-type) inverter having 2.
times.
n (n indicates an integer equal to or larger than 2) semiconductor switch elements, and can convert the DC current from the DC reactor into an AC current of a rectangular-like waveform.
Each of the switch elements can be a reverse blocking type semiconductor switch element, which can resist a voltage in the reverse direction and can be provided for each of the arms of the inverter