Hitachi, Ltd.

Hideki Ayano

Hiromi Inaba

Katsumi Ishikawa

Kazutoshi Ogawa

Tsutomu Kominami

Mami Kunihiro

Akira Mishima

Atsuya Fujino

Sadao Hokari

Kouki Yamamoto

Ikuo Yamato

Satoru Inarida

Temperature rise in semiconductor switching element that is part of a power conversion device is estimated to assess the degradation and remaining lifetime of the switching element. This is accomplished with a heat generation amount calculation unit in a calculation processor, where current command values Id* and Iq* and voltage command values vu*, vv* and vw* are used to calculate a chip loss. Current values iu*, iv* and iw* of all output phases are estimated from the current command values. The ON/OFF loss of the chip is represented by a function of an estimated value for a current flowing in each output phase, and the loss can be derived by integration with a PWM carrier frequency f. With respect to a conduction loss, a conduction time is integrated with the estimated current value and a saturation voltage, which is a function of the estimated current value.

Power conversion device and temperature rise calculation method thereof

The present invention provides a power converter which, while ensuring safety, implements control for the flow of a constant current in a specified switching element, more accurately determines the lifetime of a switching element, and reduces the number of temperature detectors. The power converter is provided with a mechanism which causes a brake device to operate or which confirms that a brake mechanism is operating. The power converter supplies current to the d-axis and the q-axis of a rotational coordinate system, within the range of the braking torque of the brake mechanism, and passes the desired current to the desired element. Furthermore, temperature detectors are attached only in chips in sections where a crack readily develops in the upper solder layer or peeling is readily generated in the wire bonding, and in chips where a crack readily develops in the lower solder layer.

Power converter

There is provided a vehicle operating system constituted of a vehicle and at least a charging apparatus, the system comprising means for enabling high-precision unmanned positioning, despite primarily vertical displacements of the vehicle due to changes in tire pressure or weight of a passenger or passengers, and hence enabling efficient, stable power feeding. The charging apparatus includes a power feeding unit, and a vehicle includes a power receiving unit for feeding power in a noncontact manner, which makes possible recharging without manual assistance. A C-shaped transformer and an I-shaped transformer are used for the power feeding unit and the power receiving unit, respectively, so that a magnetic flux induced therebetween can develop substantially in the horizontal direction, thereby feeding power stably despite changes in tire pressure and the like. Tire guides for guiding the vehicle to a power feeding position and a car stop are so used that when the vehicle comes in contact with the car stop, the power feeding unit and the power receiving unit will face each other in a correct position, thus enabling high-precision positioning at power feeding time.

Vehicle operating system

An elevator capable of supplying electric power to accessory hall devices such as up/down elevator buttons and position indicators without requiring power supply lines between the cage and each hall. A drive battery which supplies electric power to hall devices provided in each hall and a receptor connected to the battery are provided on the hall. A feeder contactable with the respective receptors, a charging device that charges the battery via the feeder and receptor are provided on the top of the cage. When the charging voltage, for example, used in a hall of the floor drops below a predetermined voltage value, the cage stops automatically at the floor and the charger charges the drive battery in the hall of the floor via the receptors and feeder.

Charger for elevator call devices

The output power line of the power converter and the common mode current circulation line are wound together on a magnetic core to form the GP coil , each end of the common mode current circulation line is connected to the grounding line of the power supply of the power converter and to the grounding line of the load, and the common mode current is circulated into the power converter via the common mode current circulation line . By means of this simple constitution, wherein the impedance in the grounding circuit loop becomes higher than that in the common mode current circulation line loop due to the function of the GP coil and consequently most of the common mode current is led into the circulation loop comprising of the common mode current circulation line, high-frequency noise interference caused by the common mode current is suppressed as a result of the canceling effect of the power line.

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Hitachi, Japan

Hideki Ayano