Komatsu Corporation

Tomohisa Sato

Norio Takahashi

Shunsuke Miyamoto

Toshiyuki Kamei

Masashi Osanai

Hiroaki Takechi

Hironori Akiba

Takayoshi Endou

Tsutomu Hatanaka

Takumi Sugihara

Jun Yamane

Takayoshi Endo

Isao Shibata

The degradation of an electrical storage devicesuch as a capacitor can be determined by a system which is not an external device but is installed in hybrid construction equipmentin a state that the electrical storage devicesuch as a capacitor is mounted. To achieve this objective, it is at least checked that the working machine has stopped. Next, when it has been checked that the working machine has stopped, a degradation state determination time control mode is entered, a motor-generator is driven at the prescribed rotational speed and the prescribed torque, and the electrical storage device rises from the prescribed start charging voltage to the prescribed end charging voltage (Step). Next, the capacitance of the electrical storage device is calculated based on the values of the rotational speed and the torque of the motor-generator during the degradation state determination time control mode, the values of the start charging voltage and the end charging voltage of the electrical storage device, and the time needed for the electrical storage device to reach the end charging voltage form the start charging voltage. Next, by comparing the calculated capacitance of the electrical storage device and the reference capacitance, the degradation state of the electrical storage device is determined.

Method and device for determining degradation state of electrical storage device in hybrid construction equipment

A voltage control device and a voltage control method capable of improving efficiency of a system as a whole even when fluctuation in voltage of a capacitor, which is a storage battery, is large are provided. A capacitor for supplying electric power to a predetermined load, an inverter connected to the load, an AC-coupling bi-directional DC-DC converter including two voltage source inverters of which direct-current terminals are connected in series so as to have additive polarity and a transformer for AC-coupling alternating-current terminals of the two voltage source inverters and having a predetermined leak inductance, with one of the two voltage source inverters connected in parallel to a capacitor, for outputting direct-current voltage obtained by increasing capacitor voltage of the capacitor to the inverter, and control unit for generating a command value of the direct-current voltage based on efficiency of the AC-coupling bi-directional DC-DC converter having a value corresponding to the capacitor voltage to output, are provided.

Systems and methods for direct-current voltage control

In order to securely prevent, even where a boosting unit is provided, a rush current from arising when a contactor is turned on during a transient state, the voltage of a surge absorbing condenser is controlled so that the voltage difference between the power source capacitor and surge absorbing condenser falls in a predetermined range. The control is performed in the following manner: of the two voltage source inverters of the AC-coupled bi-directional DC-DC converter composing a voltage converter as a boosting unit, only the one that is not connected in parallel with a power source capacitor is activated to perform a chopping operation while the generator is operated with the contactor off.

Generator driving device, hybrid vehicle, and control method for generator driving device

The present invention provides a generator motor driving device that can promptly perform discharging of charges from the capacitor during a maintenance operation, and a capacitor discharge method to be implemented in the generator motor driving device. Power is supplied from the capacitor to the generator motor being driven by the engine, and the generator motor is driven, with the engine as a load. Rated constant current control is performed on the generator motor, and rated constant voltage control is performed on the booster, until the capacitor voltage decreases to a first voltage. After the capacitor voltage decreases to the first voltage, the rated constant current control is performed on the generator motor, and voltage control is performed on the booster to maintain a predetermined ratio between the capacitor voltage and the booster output voltage to be output to the driver, until the capacitor voltage decreases to a second voltage that is lower than the first voltage.

Generator motor driving device and method for discharging charges from capacitor of generator motor driving device

A temperature control system which performs control of an object whose temperature is to be controlled as accurately as possible. The system comprises: a chiller located in a fluid circulating and supplying system, for cooling a thermal fluid returning from a vacuum chamber, a first flow control valve located in the fluid circulating and supplying system in a position between the chiller and the vacuum chamber, a bypass passage for splitting and supplying thermal fluid returning from the vacuum chamber to a position between the first flow control valve and the vacuum chamber, before it reaches the chiller, a second flow control valve located in the bypass passage, and a halogen lamp heater located in the fluid circulating and supplying system in a position between a confluence point of the bypass passage and the vacuum chamber, for adjusting the temperature of the thermal fluid passing therethrough to a set temperature.

Growing community of inventors

Hiratsuka, Japan

Tomohisa Sato