Hitachi, Ltd.

Satoru Inarida

Masahiro Nagasu

Ryuichi Saito

Katsumi Ishikawa

Kiyoshi Nakata

Yutaka Sato

Tokunosuke Tanamachi

Hideki Miyazaki

Masato Suzuki

Katsunori Suzuki

Kiyoshi Nakamura

Satoru Ito

Shin Kimura

Akira Mishima

Motomi Shimada

Hiroshi Okawara

Kento Mochizuki

Kouji Yasuda

Hideki Ayano

Wataru Miyake

Koji Agatsuma

Yoshitaka Nishimura

Yuta Oura

Mochizuki Kento

Mitsuo Iwasaki

A system corresponding to a plurality of different power sources (overhead contact line, power generator driven by engine, and fuel cells) is proposed as a method of using an optimum power supply in an electrified route and a non-electrified route. Provided are: a power conversion circuit that includes AC input ends, the number of which corresponds to the maximum number of phases among a plurality of different AC power supplies, and that converts AC power to a direct current; and switching means for switching a connection state of the AC power supplies and the power conversion circuit, wherein the connection state is switched according to the power supplies.

Driving system, driving system for railroad-vehicle, and railroad-vehicle and multi-car train mounted with same

A railway car drive system comprising a first railway car mounting a power generator, a power converter, a driving motor and a power storage; a second railway car mounting a power converter, a driving motor and a power storage; and a power transmission connecting each of the power generators and power storage; wherein the system further comprises a power management unit for controlling the generated power of the power generator and the power storage quantity of the power storage, the power storage storing the power generated by the power generator and a regenerative power, the driving motor being driven via the power converter using as power source the power generator and the power storage to thereby run the train.

Railway car drive system

A fault detection system detecting malfunctions or deteriorations, which may result in an inverter fault, is provided. The system has a temperature sensor installed on a semiconductor module to monitor a temperature rise rate. It is judged that an abnormal condition has occurred if the thermal resistance is increased by the deterioration of a soldering layer of the semiconductor module or by drive circuit malfunctions and, as a result, the relation between an operation mode and the temperature rise rate falls outside a predetermined range.

Fault detection system

An electric power translating device employs a converter for converting an AC source voltage into a DC voltage, a smoothing capacitor connected at the DC side of the converter, an inverter for inverting the DC from the smoothing capacitor into an AC and for supplying the AC to an AC motor and means for controlling the voltage, frequency or phase in the AC output from the inverter. The device further includes means for regulating at least one of voltage, frequency and phase in the AC output of the inverter based on a ripple frequency component contained in the AC output of the inverter and associated with the rectification by the converter. Whereby, beat phenomenon caused by rectification ripple is suppressed.

Control device for electric power translating device

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.

Power conversion system

A gate drive circuit of a voltage drive switching element, which is characterized by control of di/dt and dv/dt when an IGBT is switched by controlling increases in the switching time and loss of the IGBT, includes a drive means for amplifying a signal for controlling the switching operation of a voltage drive switching device including the IGBT, a means for detecting the gate voltage of the IGBT, a voltage decrease (increase) means for slowly decreasing (increasing) the output voltage when the drive means is turned on (off) in the course of time, and a voltage increase (decrease) means for slowly increasing (decreasing) the output voltage. By switching from the voltage decrease (increase) means to the voltage increase (decrease) means according to the detected value of the gate voltage of the IGBT, di/dt and dv/dt are controlled when the IGBT is turned on (off).

Gate drive circuit of voltage drive switching element

In a pulse width modulation control method and system for an electric power converter, in order to suppress the occurrence of lower order harmonics and fractional order harmonics in a direct current component even in a condition where a carrier frequency is several times as small as the frequency of a command value, pulse width modulation pulses for driving semiconductor elements in the electric converter are calculated by comparing a command signal from a command value generating means with a carrier signal having a continuous triangular-wave and a constant period. For this purpose, there is provided a means for separately calculating a time product of a command value of the command signal from the command value generating means and a time product of the pulse width modulation pulses and for calculating a difference value representing a difference between both time products. The pulse width modulation pulse is then calculated using the calculated difference value to compensate the command signal received from the command value generating means.

Pulse width modulation control system for electric power converter

A power conversion apparatus has a PWM power converter coupled to an A.C. power supply on one side and to a D.C. load on the other side, a voltage controller for adjusting the D.C. output voltage from the converter, a power factor controller for adjusting the power factor on the A.C. side of the converter, a command generator for generating a PWM modulation factor and a phase signal in response to the voltage and an output from the power factor controller, and a PWM modulation unit for controlling the converter in response to these command signals. The power factor controller is controlled to reduce its power factor when a control parameter relating to the modulation factor of the converter approaches its limit value, and the power of the D.C. load is limited when a control parameter relating to the input power of the converter approaches its limit value, such that the power factor of the power converter is allowed to be reduced and the power of the D.C. load is limited respectively in each designated region, thereby preventing any overcurrent even if the power supply voltage fluctuates. As a result, continuous operation is maintained, making it possible to reduce the capacity of the converter required for generating the same output power over the conventional converter.

Power conversion apparatus

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Hitachinaka, Japan

Satoru Inarida