摘要:
A partial discharge measurement device (10) has: an impulse voltage application unit (13) ; a measurement control unit (20); and first and second partial discharge detection unit (10a, 10b). The measurement control unit (20) has: a first and a second detector level partial discharge counting unit; and a partial discharge resistance evaluation unit. Each of the first and the second detector level partial discharge counting units outputs a first or second detection signal when the first or second detection signal exceeds a predetermined specified value. The partial discharge resistance evaluation unit counts the number of occurrences of partial discharge based on an output from the first and second detector level partial discharge counting unit, and regards the impulse voltage value at which the count value has reached a predetermined value as a partial discharge inception voltage under the repeated impulse voltage application.
摘要:
A bidirectional insulated DC/DC converter narrows a pulse width (± or ²) of an AC fundamental wave voltage (Va or Vb) corresponding to a higher DC voltage of two DC voltages (Ea, Eb), to cause effective values of the AC fundamental wave voltages (Va and Vb) to coincide with each other, and then, sets a phase difference (¸) between the AC fundamental wave voltages (Va, Vb) in accordance with a value and a direction of a current that is desired to flow. Accordingly, even when the difference between the two DC voltages (Ea, Eb) greatly varies, DC power can be stably transmitted and received.
摘要:
The present invention provides a power supply apparatus that automatically determines a driving frequency of an inverter in a system including a plasma generator and the power supply apparatus. A power supply apparatus (10) according to the present invention includes a controller (6) that performs the following action and resonance means (7) for creating a resonance state between the power supply apparatus (10) and a plasma generator (5). That is, the controller (6) changes, when a value of electric power input equal to 100% (or a value of electric power input equal to or more than a threshold % and equal to or less than 100%) of a rated power is instructed, an inverter frequency and obtains an inverter output power factor for each of a plurality of inverter frequencies. Then, the controller (6) determines, as a driving frequency of the inverter, one of the plurality of inverter frequencies at which the inverter output power factor is maximized.
摘要:
A power converter 100 includes a DC capacitor C, semiconductor switch groups each of which includes semiconductor switches connected in series to each other, bridge-cells llu-j, 11v-j, and 11w-j each of which includes the DC capacitor C and two semiconductor switch groups connected in parallel to the DC capacitor C, a delta connection unit 10 including delta-connected bridge-cells and a integrated control unit 1 for controlling a circulating current flowing in the delta connection unit such that each of DC-capacitor by-phase average values follows a DC-capacitor three-phase average value, each of the DC-capacitor by-phase average values being obtained by averaging voltage values of the DC capacitors at a corresponding phase of three phases, and the DC-capacitor three-phase average value being obtained by averaging voltage values of the DC capacitors at all of the three phases.
摘要:
This power conversion device is provided with an energy storage unit (5) which receives and stores voltage of a self-power-feeding device (3); and a bypass unit drive device (6) which, when a voltage of the self-power-feeding device (3) becomes smaller than a predetermined lower limit value, causes a bypass unit (4) to perform a short-circuiting operation by power stored in the energy storage unit (5). Thus, by appropriately setting the above voltage lower limit value as a threshold value for the short-circuiting operation, it becomes possible to swiftly and reliably perform a short-circuiting protection operation even if a cell converter (100a) has failed. Thus it is possible to always safely continue the operation of the power conversion device.
摘要:
An object of the present invention is to provide an ultrasonic bonding tool capable of bonding a lead wire, without any trouble, even to a surface of a thin-film base having a plate thickness of 2 mm or less such as a glass substrate. In the present invention, a surface portion of a chip portion (1c) of an ultrasonic bonding tool (1) used in an ultrasonic bonding apparatus has a plurality of planar portions (10) formed so as to be separated from one another, and a plurality of concavities (11) formed between the plurality of planar portions. Each of the plurality of planar portions (10) has a flatness of 2 µm or less.
摘要:
An alternating current motor driving system provided with a plurality of alternating current generators, a common distribution bus, a plurality of power conversion devices, a plurality of power conversion control circuits, and a plurality of alternating current motors. According to one embodiment, each of the power conversion control circuits generates a current instruction for the corresponding alternating current motor based on a corrected speed instruction obtained by correcting a speed instruction for the corresponding power conversion device according to a bus frequency detection output. According to another embodiment, each of the power conversion control circuits generates a speed instruction for the corresponding alternating current motor in the range equal to or lower than an upper limit speed adjustment output obtained by adjusting an upper limit of the speed instruction for the corresponding alternating current motor according to a bus frequency detection output. According to still another embodiment, each of the power conversion control circuits has a current instruction unit for generating a current instruction for the corresponding alternating current motor in the range equal to or lower than an upper limit current adjustment output obtained by adjusting an upper limit of the current instruction for the corresponding alternating current motor according to a bus frequency detection output. Each of the power conversion devices controls, in accordance with a load fluctuation of the common distribution bus, an effective power exchanged with the corresponding alternating current motor based on the current instruction from the corresponding power conversion control circuit, thereby controlling the bus frequency to be a predetermined value corresponding to the corrected speed instruction, a predetermined value regulated by the upper limit speed adjustment output, or a predetermined value regulated by the upper limit current adjustment output.
摘要:
An electrical power converter (1) includes: AC voltage terminals U, V, and W; DC voltage terminals P and N; a converter cell series unit composed of one or more converter cells (10) connected in series between the AC voltage terminals U, V, and W and the DC voltage terminals P and N, each converter cell (10) including a semiconductor element and a capacitor; and a first inductance (301) connected in series to the converter cell series unit, between, of the DC voltage terminals P and N, a DC voltage terminal at the lowest potential with respect to the ground, and the AC voltage terminals U, V, and W.