Nishimu Electronics Industries Co., Ltd.

Kyushu University

Taiyo Yuden Co., Ltd.

Matsushita Electric Works, Ltd.

Kosuke Harada

Hiroshi Sakamoto

Takazi Nakamizo

Katsuaki Murata

Hideaki Abe

Kimihiro Nishijima

Fukutoshi Tominaga

Cheng-Jen Chen

Akihiko Katsuki

The number of switches on the primary winding side of a transformer is decreased and ripples contained in the output voltage are greatly reduced. In a state I, Sia and Sib are switched ON, in a state II, Sim and Sia are switched ON, in a state III, Sia and Sib are switched ON, and in a state IV, Sim and Sib are switched ON. As a result, in the states I to III, a transformer Trsa is connected to a capacitor Ci, in the state IV, the transformer Trsa is connected to an input power source Vi supplying an electric current in the direction opposite to that of the capacitor Ci. Further, in states I, III, and IV, the transformer Trsb is connected to the capacitor Ci, and in state II, the transformer Trsb is connected to the input power source Vi supplying an electric current in the direction opposite to that of the capacitor Ci. Further, in states I to III, the electric current generated on the secondary winding side of the transformer Trsa is supplied by a rectifying diode Doa to a load R, and in states I, III, and IV, the electric current generated on the secondary winding side of the transformer Trsb is supplied by a rectifying diode Dob to the load R.

Power source apparatus

A non-contact electrical power transmission system is capable of providing a large supply current of uniform level at an optimum transmission efficiency. The system includes a power circuit including a power supply of providing a high frequency voltage across a power winding, and a load circuit for energizing a load. The load circuit is composed of a secondary winding, a matching capacitor, a rectifier, and a choke coil. The secondary winding is magnetically coupled to the power winding so as to generate an induced high frequency voltage and to provide a leakage inductance to the load circuit. The matching capacitor is connected across the secondary winding to be cooperative with the leakage inductance and with the secondary winding to form an oscillatory circuit which provides an oscillating voltage across the matching capacitor for generating a supply current being fed through the rectifier and the choke coil to the load. The matching capacitor is selected to have a specific capacitance such that the oscillating voltage reaches its extreme each time the inducted high frequency voltage reverses its polarity. The choke coil is connected in circuit to smoothen the supply current. Thus, the supply current of uniform level can be fed to the load, reducing a possibility of incurring a noise on the supply current, yet minimizing an impedance between the supply circuit and the load circuit for realizing an optimum efficiency of converting the high frequency voltage into the supply current.

Non-contact electrical power transmission system

The disclosed power source apparatus includes a direct current (DC) source connected to the primary side of a transformer through a main switching element, a shunt circuit connected in parallel to the main switching element the shunt circuit being a serial circuit having an auxiliary switching element and a capacitor, and a control circuit connected to the main switching element so as to operate the main switching element at a duty ratio for generating a pulse-width-modulated output voltage at the secondary-side of the transformer depending on the duty ratio. The control circuit is also connected to the auxiliary switching element so as to turn off the auxiliary switching element when the main switching element is on or 'closed' and to turn on the auxiliary switching element when the main switching element is off or 'open'. The auxiliary switching element and the capacitor in the shunt circuit are such that the shunt circuit has a small impedance at low switching frequencies of the main switching element.

DC-DC converter with surge voltage prevention

A switching power source means comprises a DC voltage source, a first switch element, a low-pass filter connected to the DC voltage source through the first switch element, and a second switch element connected to the input end of the low-pass filter, the switch elements being coupled to the DC voltage source either directly or through a transformer and being operable in such a manner that an output of DC or AC at a desired frequency can be derived across the output end of the low-pass filter. With the invention, a reactor is connected in parallel across the input end of the low-pass filter, to charge and discharge parasitic capacitances of the switch elements, preferably by being provided with a saturable core accompanied by an additional winding supplied with a load current, thus preventing surge currents in the switch elements.

Switching power source means

A switching power source means comprises a DC voltage source, a first switch element, a low-pass filter connectable to the DC voltage source through the first switch element, and a second switch element connected to the input end of the low-pass filter, the switch elements being coupled to the DC voltage source either directly or through a transformer and being operable in such a manner that an output of DC or AC of a desired frequency can be derived across the output end of the low-pass filter. With the invention, a reactor is connected in parallel across the input end of the low-pass filter, which reactor being is adapted to charge and discharge parasitic capacitances of the switch elements, thus preventing surge currents in the switch elements.

A switching power source comprising a pair of output terminals, a first switch element, a reactor and a filter which are connected to each other in series between one of the terminals of an input DC power source and one of the output terminals; a second switch element connected between a connecting node for the reactor and the filter and the other terminal of the input DC power source; and means for causing energy stored in the reactor to be fed back for regeneration to the input DC power source when the switch elements are turned off, wheein the switching power source is characterized by that the first and second switch elements are alternatively actuated for ON-OFF actions at a prescribed time ratio.

Switching power source device having energy recovery

A ferroresonant three-phase constant AC voltage transformer comprising three transformer iron cores with one for each corresponding input supply phase, primary windings and secondary windings formed on each of the transformer iron cores, series reactance components or reactors connected in series, with the primary windings, automatic voltage regulating means for controlling secondary output voltages generated at the secondary windings to a predetermined target value, compensating windings formed so as to be inductively coupled to each of the series reactance components or reactors, and means for connecting the compensating windings in series with each other to form a closed loop circuit. The secondary output voltages are theoretically kept in balanced condition even when the loads or the primary input voltages or both are unbalanced.

Ferroresonant three-phase constant AC voltage transformer arrangement

An AC voltage regulator includes an output voltage sensing and regulating device having a suitable filter characteristic to attenuate AC components therein occurring in the frequency ranges corresponding to the almost periodic oscillations or abnormal oscillations, or high frequency components of distorted waves which appear in the AC output voltage and are causes for such abnormal oscillations. The AC voltage regulator does not need to use a dummy load to suppress almost periodic oscillations even when the load is extremely small. The output voltage of the AC voltage regulator is free from abnormal oscillation components such as almost periodic oscillations and low frequency oscillations.

Alternating current voltage regulator using a feedback loop with step

A constant voltage regulator involving a feedback loop by which frequency dependence may be eliminated and at the same time, hunting phenomenon in case of low load can be suppressed without inserting a dummy resistance or a reactor in its circuit, whereby high reliability may be compatible with low cost. The constant voltage regulator comprises a linear reactor and a resonance capacitor connected in series to an input power source, and a variable reactor connected in parallel with said resonance capacitor and involves a feedback loop, a saturable reactor being used as said variable reactor, and current flowing through said saturable reactor being subjected to feedback control in response to load or output voltage.

Ferroresonant constant AC voltage regulator

A power conversion device of simple configuration for a solar cell which permits the solar cell to be connected to the commercial power source and enables the maximum electric power corresponding to the amount of incident sunlight to be drawn from the solar cell. A power conversion device for a solar cell of this invention comprises a voltage controlled oscillator capable of generating oscillation with a frequency which is the function of the dc output voltage of said solar cell, an inverter controlled based on the output frequency of said voltage controlled oscillator to receive the dc output current of said solar cell and convert said dc output current into an alternating current, and an inductor serving to connect the ac output from said inverter to a commercial power source.

Power conversion device for solar cell

An uninterruptible ac power supply permits parallel operation between a commercial ac line and an inverter unit, greatly simplifies the monitoring of the commercial ac line and minimizes the transient of output voltage during the switching of mode. The uninterruptible ac power supply is comprised of an iron core divided with magnetic shunts into three sections and has an output winding, a winding for a commercial ac line and a winding for an inverter unit, one each wound on the aforementioned three sections of the iron core, the said three windings so disposed that the output winding is wound on one terminal section and the windings for the commercial ac line and the inverter unit are wound on the remaining two sections.

Growing community of inventors

Fukuoka, Japan

Kosuke Harada