Tdk Corporation

Yoshinobu Takayanagi

Katsuaki Tanaka

Yoshihisa Okita

Kazuyuki Itoh

Kunihiro Sato

Akihiro Unno

Saiki Shigemori

An electromagnetic induction power generator includes a magnetic core attachable to a power transmission/distribution line, a power generating coil wound around the magnetic core, and a switching power supply circuit that converts AC appearing at both ends of the power generating coil into DC. The switching power supply circuit stops its switching operation based on a DC voltage level. The stop of the switching operation increases reactive power, allowing a stable power generating operation, i.e., a stable supply of active power irrespective of the amount of current flowing through the power transmission/distribution line. In addition, the amount of the reactive power can be finely adjusted based on the length of a period during which the switching operation is stopped, allowing a finer control of the reactive power.

Electromagnetic induction power generator

A switching power supply unit is provided, which can output a DC voltage and an AC voltage with a minimized installation space. A switching circuit is provided between a winding of a transformer and a main battery. A rectifier circuit is provided between other windings of the transformer and an accessory battery. Output terminals for outputting an AC output voltage are provided at the other side of the transformer, the AC output voltage being generated based on a DC input voltage inputted from the main battery. A DC output voltage and the AC output voltage are generated based on the DC input voltage, and then outputted. The transformer is shared by a generation path of the DC output voltage and a generation path of the AC output voltage. An AC voltage input section to be inputted with the AC input voltage from external equipment may be provided at the other side of the transformer.

Switching power supply unit

Provided is a switching power supply unit being able to perform voltage conversion between two DC power supplies, and perform appropriate charge operation based on an inputted AC voltage. When a main battery is preferentially charged, an SW control section performs control such that a duty ratio is fixed in switching operation of a switching circuit, and a duty ratio is variable in switching operation of a bidirectional switching circuit. On the other hand, when an accessory battery is preferentially charged, the SW control section performs control such that a duty ratio is variable in switching operation of each of the switching circuit and the bidirectional switching circuit. When the accessory battery is preferentially charged, the SW control section may perform control such that the duty ratio is fixed in switching operation of the switching circuit, and a duty ratio is variable in switching operation of a switching element.

The present invention provides an inverter with a simple configuration capable of preventing occurrence of excessive rush current. A current detection circuit detects an AC output current flowing out from an output filter circuit. When the absolute value of the AC output current becomes equal to or larger than a threshold, a reset control unit and a drive pulse generation circuit control a DC/AC inverter so as to re-start operation after the AC output voltage becomes 0V. For example, even in the case where a capacitive load is connected during operation of the inverter or in the case where the load includes a standby circuit, excessive rush current is prevented.

Inverter for driving a load including a capacitive element in an input stage

A switching power supply unit is provided, in which input terminals of an AC voltage can be made common to output terminals of an AC voltage. A first switching circuit is provided between a winding of a transformer and a main battery. A second switching circuit is provided between another winding of the transformer and input/output terminals. A third switching circuit is provided between the second switching circuit and the input/output terminals. Each of the first to third switching circuits includes a bidirectional switch (configured of a pair of one switching element and one diode connected in parallel to each other). A circuit for outputting an AC output voltage can be common to a circuit for inputting an AC input voltage to charge the main battery.

A power conversion apparatus capable of reducing the conduction loss to achieve high efficiency yielding a downsized and weight-reduced apparatus and a method for driving such a power conversion apparatus is disclosed. A power conversion apparatus comprising a switching-element driving circuit which includes a current transformer having a primary coil connected to an current control type switching element, and a driving-current generating circuit formed of a secondary coil of the current transformer and a rectifying circuit connected to the secondary coil, wherein an output current generated in the driving-current generating circuit is supplied to the switching element as a driving current of the switching element, and a method for driving the switching element of such a power conversion apparatus are disclosed. This method comprises the steps of detecting an output current of the switching element, and extracting a part of the output current of the driving-current generating circuit out of the switching-element driving circuit so as to variably controlling the driving current of the switching element in response to the output current of the switching element. Preferably, the output current of the driving-current generating circuit extracted out of the switching-element driving circuit is supplied to any other auxiliary power supply as a regenerative power.

Method and apparatus for driving switching element in power converter

In a power conversion apparatus using a semiconductor switching element, a collector-emitter voltage detecting device is provided to detect the collector-emitter voltage in the semiconductor switching element in the power conversion apparatus in order to comprehensively reduce switching loss and conduction loss arising in a switching element. A base current supplied to the switching element is controlled based on the detected collector-emitter voltage so as to control the collector-emitter voltage or control a regenerative power to be transmitted from a switching element driving power supply to an external auxiliary power supply or the like. This provides an optimum driving in consideration of factors including dispersion in a specific current amplification factor (hfe) of the switching element, variance in the hfe caused by temperature, and variance in the hfe to a current flowing through the switching element, for reducing a sum of conduction loss and driving power of the switching element.

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Tokyo, Japan

Yoshinobu Takayanagi