Abstract: In a co-generated power supply system for performing dispersed power supply to a load, a wind turbine generator, a solar cell and a fuel cell whose rated voltages are made equal to a rated voltage of a storage battery are used as DC power sources. These DC power sources, a commercial AC power source and the load are connected to each other via a bi-directional electronic transformer. Thus, the co-generated power supply system, in which the electric power of a natural energy system having many fluctuation factors is combined with stable electric power such as a load leveling battery or a fuel cell, allows the stable electric power to be supplied to the load via the electronic transformer commonly, thereby reducing the cost and enhancing the performance of the entire system.

Abstract: An AC voltage regulator, which not only has a fast response speed with respect to input voltage fluctuations but also is small in size and light in weight and is capable to boost an input voltage, comprises a high-frequency transformer 4, a first bi-directional semiconductor switch circuit 3, a second bi-directional semiconductor switch circuit 5 and a third bi-directional semiconductor switch circuit 6; an input AC voltage is ring-modulated by the first bi-directional semiconductor switch circuit 3 and the obtained ring-modulated voltage is transformed at a high frequency by the high-frequency transformer 4 and then demodulated by the second bi-directional semiconductor switch circuit 5, and the obtained AC demodulated voltage is added to the input AC voltage to produce an AC raised voltage, and the AC raised voltage is pulse width modulated by the third bi-directional semiconductor switch circuit 6, which is controlled to become ON only while the second bi-directional semiconductor switch circuit 5 is OFF,

Abstract: An AC-AC/DC converter for converting an AC input or an AC input voltage-divided by a capacitor into a high frequency AC. The converter includes a modulator for turning bi-directional AC switches on and off to convert the AC input or the AC input voltage-divided by the capacitor into a high frequency AC; a high frequency transformer for varying a voltage ratio of the high frequency AC; bi-directional AC switches for demodulating an output from the high frequency transformer into an AC output or rectifying the output into a DC output; a high frequency filter for removing high frequency components from the AC or DC output; and a control unit for controlling the AC switches using a pulse width or pulse phase modulation technique. Through the bi-directional AC switches, the converter can sequentially control an AC or DC input such that the AC or DC output has a value in a range from a maximum value of the positive phase or polarity, passing through zero, to the maximum value of the negative phase or polarity.

Abstract: A power factor improving circuit for reducing a harmonic current component contained in an AC input current and for achieving an excellent power factor and efficiency in a circuit having a rectifier circuit, provided between a rectifier circuit and a half-bridge-type inverter, including a discharging diode and a smoothing capacitor connected in series to each other and in parallel between output terminals of the rectifier circuit, a charging half-bridge rectifier connected to the smoothing capacitor, and a high-frequency capacitor and high-frequency inductor connected in series to each other and between an input terminal of the charging half-bridge rectifier and a connecting point of two transistors of the half-bridge-type inverter.

Abstract: A method for providing an uninterruptible power supply to a load both at ordinary times and in an emergency. At ordinary times, commercial AC input power is modulated into high-frequency AC power, which is then applied to a primary winding of a high-frequency transformer having the primary winding, a secondary winding and a tertiary winding. High-frequency AC power induced in the secondary winding from the primary winding is demodulated into AC output power, which is then supplied to the load. High-frequency AC power induced in the tertiary winding from the primary winding is rectified into DC power, with which a storage battery is charged. In an emergency, DC power from the storage battery is converted into high-frequency AC power, which is then applied to the tertiary winding. High-frequency AC power induced in the secondary winding from the tertiary winding is averaged, thereby producing AC output power, then the AC output power is supplied to the load.

Abstract: A single phase AC input voltage is subjected to a single-phase full-bridge rectifier to obtain a first rectified voltage. The first rectified voltage has a fundamental DC component and a harmonic component, the harmonic component being defined by a ripple voltage of the first rectified voltage. The first rectified voltage is then subjected to an auxiliary rectification in which the ripple voltage of the first rectified voltage is rectified. A resultant auxiliary DC component is added to the fundamental DC component to obtain a DC component of a rectified output voltage.

Abstract: A three phase full-bridge rectifier circuit and a pseudo four phase full-bridge rectifier circuit each include a phase conversion circuit for converting an input single phase AC input voltage into a three phase AC voltage or a four phase AC voltage, respectively. The phase conversion circuit includes an inductor and a capacitor and is connected to the inputs of a three phase of four phase full-bridge rectifier circuit.