Hitachi, Ltd.

Hitachi Construction Machinery Co., Ltd.

Hitachi Engineering Co., Ltd.

Keizo Shimada

Naoshi Sugawara

Akira Kikuchi

Takashi Ikimi

Yasuhiro Kiyofuji

Kazuhiro Imaie

Hideaki Kunisada

Hideyasu Umetsu

Takashi Yagyu

Yoshimi Sakurai

Masashi Toyota

Hikaru Meguro

Hiroshi Ikarashi

Akihiko Kanouda

Akira Kobayashi

Tomohiko Yasuda

Kenji Kubo

Norikazu Tokunaga

Kichio Nakajima

Toshikazu Minoshima

Hidefumi Shirahama

Ikuo Yamato

Yorito Jifuku

Tomoaki Mino

Satoru Inukai

Takayasu Nakane

Tetsuhiro Fujimoto

Shintarou Oku

An electric drive vehicle having an induction motor for braking or driving wheels, a motor controller for controlling the induction motor, and mechanical brakes for braking the wheels, wherein while the vehicle is in halt in a state that the mechanical breaks are not operating, the motor controller applies DC voltage or AC voltage in a frequency range of &#x2212;1 Hz to +1 Hz to the stator of the induction motor to make the induction motor generate torque for stopping the vehicle and maintain the vehicle in a halt state.

Electric drive vehicle

An electric drive vehicle having a power generator coupled to an engine, a first power converter connected with the power generator for converting the AC power generated by the power generator to DC power, a second power converter connected with the first power converter, for converting the DC power to AC power, a power consuming device for consuming the DC power, connected to a DC circuit between the first and second power converters, an electric motor connected with the second power converter, and at least one wheel driven by the electric motor, wherein the vehicle has a first control mode for controlling the output of the electric motor and a second control mode for controlling the power consumed by the power consuming device, and the second control mode performs such control that the operations of the second power converter and the electric motor in the first control mode are simulated.

An electric motor control system including a generator, an AC motor, a power converter for driving the AC motor using a DC output voltage of the generator, and an electric motor controller for controlling the power converter. The electric motor controller controls the power converter by predicting a change in the DC voltage.

Electric motor control system, series hybrid vehicle, electric motor control apparatus, and electric motor control method

In an electric drive system for a vehicle, an alternator is driven by an engine to generate electric power which is used to drive a motor to generate a driving force. During a retardation of the vehicle, the motor is operated as an alternator to convert kinetic energy to electric energy which is used to retard the vehicle. A retard resistor is provided for absorbing electric energy generated during the retardation state. The retard resistor is cooled down by an AC blower.

Electric drive system for vehicle, electric control system for vehicle, electric drive method for vehicle

In an electrically driven vehicle having a controller, the vehicle has a steering angle sensor for outputting a detected value of a steering angle of the vehicle, the controller includes a first torque order pattern along which a torque order for a first electric motor is determined and a second torque order pattern along which a torque order for a second electric motor is determined, and the first and second torque order pattern are modified on the basis of the detected value of the steering angle so that the torque order determined along the second torque order pattern is greater than the torque order determined along the first torque order pattern under the identical velocity when the vehicle turns to the left, and the torque order determined along the first torque order pattern is greater than the torque order determined along the second torque order pattern under the identical velocity when the vehicle turns to the right.

Electrically driven vehicle

By reduction in loss and noise of a three-phase reactor on the AC side of an electric power converter, compactness and reduction in weight of the reactor are realized, and countermeasures for heat and noise are reduced, and a specific frequency component is reduced, thus cost reduction and conversion efficiency are improved, and carriers of a controller are prepared in correspondence to the phases of the electric power converter, and moreover a phase difference of each carrier is set properly.

Electric power converter for reducing generated high frequency components

Electric power converter

A motor is driven with variable frequency AC power converted from DC power, and an AC output power from the motor is converted to DC. In the conversion, an electromotive force regenerated by the motor is consumed by a plurality of resistors. When the consumption of the electromotive force is impeded in any of systems including any of the plurality of resistors, the electromotive force is consumed by the systems including the remaining resistors. Even if a system including any of the plurality of resistors fails, the electromotive force can by consumed by the other systems including the remaining resistors, thus providing a reliable rheostatic brake.

AC drive apparatus, vehicle control apparatus, and power conversion method and vehicle control method

An electric power converter having an AC input and AC output, and comprising a power rectifier and a power inverter having a DC three-wire circuit, wherein means for detecting a current or a voltage is connected between the AC power source and ground. When a current or a voltage is detected, an alarm is produced or the apparatus is halted. This makes it possible to judge whether the power inverter is in a state capable of producing an excessively large potential.

A sine wave input converter provided with a phase sequence computation unit which inputs two line voltages or two phase voltages of the three phase ac power supply, computes the phase of a sine wave voltage of one of these two inputs, and determines on the basis of computation using these two input voltages and the phase whether the phase sequence is positive or antiphase, which is determined depending on whether the result of computation assumes a constant value, or becomes a sine wave oscillating between positive and negative values. Power supply interruption can be determined from the same computation result.

Electric power conversion apparatus

In a power converter apparatus having a three-phase AC power supply connecting unit, a positive side capacitor, a negative side capacitor, first-phase and third-phase converting circuits each including switching elements connected in series, and a common phase for connecting a neutral polarity to a second phase, there are provided a common phase converting circuit including two switching elements connected in series between positive and negative polarities, a change detector for detecting a temporal change of an electric current flowing through the common phase, and a duty controller for changing the on-off duty of the switching elements in the common phase converting circuit on the basis of the temporal change.

Method and apparatus for power converting AC into DC or DC into AC by

In a uninterruptible power supply in which a plurality of inverters are operated in parallel, a current control loop is provided which responds to the magnitude of an output current of each inverter brought into parallel running to change a command value for a voltage waveform control circuit associated with each inverter, and the gain of the current control loop is made to be variable, whereby currents shared by the inverters can be set desirably to effectively suppress a cross current flowing between the inverters upon establishment of parallel running.

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Hitachi, Japan

Keizo Shimada