Kokusan Denki Co., Ltd.

Kaoru Shinba

Masanori Nakagawa

Mitsuyoshi Shimazaki

Masahiko Endou

Katsumi Yamamoto

Yoshihiro Sugisawa

Yutaka Inaba

An inverter controlled generator set including: a power supply unit that uses a generator driven by an engine as a power supply to output a DC voltage; an inverter device that converts the output voltage of the power supply unit into an AC voltage; and a rotational speed control unit that controls a rotational speed of the engine so as to be kept at a target rotational speed suitable for a load applied to the inverter device, wherein the rotational speed control unit is comprised so that a settling time when the rotational speed of the engine is caused to converge to the target rotational speed in a state where the load is above a set value is longer than a settling time when the rotational speed is caused to converge to the target rotational speed in a state where the load is below the set value, in order to minimize an operation sound of the engine when the load is intermittently driven.

Inverter controlled generator set

A method for controlling an inverter controlled generator set which comprises a DC power source section having as a power source a generator driven by an engine and an inverter which converts an output of said DC power source section into an AC output, the method comprising a step of controlling a rotational speed of the engine so that the AC output suitable for driving a load is output from the inverter; wherein, after the engine is started, the rotational speed of the engine is controlled by a constant speed control mode for maintaining the rotational speed of the engine at a set rotational speed, and the rotational speed of the engine is increased to the set rotational speed; and wherein an operation of the inverter is started after the rotational speed of the engine reaches the set rotational speed.

Inverter controlled generator set and method for controlling the same

An inverter unit comprising component parts including at least an inverter and a filter which removes a high harmonic wave component from an output of said inverter, wherein said component parts are housed in an aluminum case having a bottom wall portion and a side wall portion, said filter includes a coil which is wound around a core extending straight and is arranged at a position closed to one end of said case, an end portion of said core being wound with said coil is arranged closed to an inner surface of said side wall portion of the case, and a ferromagnetic plate, which leads magnetic flux coming in and out said end portion of the core arranged closed to said wall portion of the case to the direction along the inner surface of the side wall portion of the case, is disposed between said end portion of said core and said inner surface of said side wall portion of the case.

Inverter unit

A method of controlling an inverter power generation apparatus adapted to stop an operation of an inverter by stopping supplying a drive signal to a switch circuit of the inverter when an overload continuation time exceeds a first setting time in the state where a load current detected by a load current detector is equal to or more than a first overload judgment value and equal to or less than a second overload judgment value, to stop the operation of the inverter when the overload continuation time exceeds a second overload judgment value set in accordance with an output voltage of the inverter in the state where the load current exceeds the second overload judgment value and the output voltage of the inverter is higher than a short circuit judgment value and to stop the operation of the inverter immediately when the load current exceeds the second overload judgment value and the output voltage of the inverter is equal to or less than the short circuit judgment value whereby the inverter can be positively protected while an induction motor having a larger starting current flowing therethrough.

Method and apparatus for overload-controlling inverter power generation apparatus

An inverter generation apparatus comprising means to obtain a reference duty ratio of predetermined switch elements of an inverter on-off driven to each of switch timings so as to have a desired waveform of an AC voltage obtained across load connection terminals, means to obtain correction coefficient for the duty ratio relative to a value reflecting a variation in an output voltage of a DC power circuit, means to obtain a real duty ratio by multiplying the reference duty ratio by the correction coefficient whereby the switch elements of the inverter are on-off driven in the real duty ratio so that the desired value of the AC voltage across the load connection terminals.

Pulse with modulation inverter generation using a correction co-efficient and a reference to the ratio to obtain a real duty ratio

A method of controlling a parallel operation of two inverter power generation apparatuses wherein an unbalance of outputs from the two inverter power generation apparatuses is cancelled by judging that the outputs of the two inverter power generation apparatuses have the collapse of the balance between them when a DC power supply voltage obtained from a DC power supply section exceeds a judgment value set at a value equal to or more than a non-load output voltage of the DC power supply section and allowing an overload operation of the inverter power generation apparatus of higher output voltage among the two inverter power generation apparatuses so as to lower the output voltage of the corresponding inverter power generation apparatus.

Method of controlling inverter power generation apparatus

A method of controlling an electric power source apparatus including an electric power converter circuit which converts an output of an electric power source into DC or AC output and load connector terminals across which is applied an output of said converter circuit, which includes the steps of detecting a waveform of the load voltage across the load connection terminals after the output of the electric power converter circuit is stopped when an overcurrent flows through the load connection terminals, of judging a cause due to which the overcurrent flows, and of controlling said converter circuit according to the result of the judgement, wherein the electric power converter circuit is kept stopped when it is judged that the overcurrent is caused by an increase in the load and the electric power converter is so controlled that the waveform of the voltage applied across the load connection terminals from the electric power converter circuit is consistent with the waveform of the voltage detected by the voltage waveform detection step when it is judged that the overcurrent is caused by a voltage applied from another power source.

Electric power source apparatus including electric power converter circuit and method for controlling the same

A method of controlling an electric power supply apparatus with an electric converter circuit adapted to detect a phase difference between a waveform of a voltage across load connection terminals and a waveform of a reference voltage from time difference between zero cross points thereof and shift the phase of the reference voltage so that the phase difference is within a set range when it is decided that the phase difference is out of the set range whereby the phase of the output voltage across the load connection terminals is so controlled that it is coincident with that of an external voltage applied across the load connection terminals.

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Numazu, Japan

Kaoru Shinba