TRANSFORMERLESS POWER CONVERSION DEVICE USING CHOPPER

摘要

A transformerless power current using a chopper technology using a chopper technology is provided to reduce an installation area and weight by not requiring an input and output transformer. Rectifiers(51) reduce a harmonic content flowing reversely to the input side through the pulse width modulation(PWM) regardless of the voltage of the commercial AC source and extract the alternating current waveform and phase. Bidirectional convertors(52) are connected to the rectifier and convert into the direct current boost voltage or drop voltage according to the voltage of the AC power supply and charge the battery or output the normal load. DC link parts(53) are connected to the battery and control the charge/discharge voltage and current of the battery. Neutral point adjusting units(54) extract an absolute value of the current by applying the unbalanced load to make the neutral point maintain a constant level with regard to the neutral point movement phenomenon generated without an insulation transformer of an output circuit. Inverter units(55) divide the pulse within the half period of the output waveform into a plurality of pulses in order to stabilize the power of a variable load and control an output voltage at high speedy by removing or reducing the harmonic. Bypass circuit units(61) connect a total of three pairs of silicon control rectifiers in series to each RST line and in parallel to a peak output of the commercial AC power and output the load power by removing an over current and the harmonic of the commercial AC power. One pair is composed of two silicon control rectifiers.