Mitsubishi Electric Corporation

Yoji Tsutsumishita

Yoshitomo Hayashi

Akira Tanabe

Taichiro Tamida

Masayuki Uematsu

Kosuke Tsujikawa

Hiroshi Nishizawa

Yoshiharu Kaneda

Toru Oka

Toshiki Tanaka

Hirotaka Muto

Shinichi Furutani

Masaya Harakawa

Kazuhiko Tsutsui

Ryuichi Nishiura

Akiko Tabuchi

Jun Hattori

Yuji Nojiri

Yoshimasa Watanabe

Manabu Ohashi

Hiroyoshi Takeuchi

Tomokazu Ogawa

An insulation detector for highly accurately detecting or measuring, with a simple configuration, insulation resistance of a load or an apparatus to a ground or a housing and connected to an electric apparatus including one or both of an intra-apparatus capacitor and a battery, the insulation detector including an intra-insulation detector capacitor, a voltage detecting unit that detects a voltage of the intra-insulation detector capacitor, and a current-path forming switch for connecting the ground or the housing, the intra-apparatus capacitor, and the intra-insulation detector capacitor in series and forming a current path including insulation resistance of the electric apparatus. The insulation detector measures the insulation resistance by measuring a time constant of a change in the voltage of the intra-insulation detector capacitor. A capacitance value of the intra-insulation detector capacitor is a value negligible in the measurement of the insulation resistance compared with a capacitance value of the intra-apparatus capacitor.

Insulation detector and electric apparatus

A power regenerative converter, includes: a power module configured to include rectifiers and regenerative switches; a smoothing capacitor connected to direct-current power supply terminals, and that accumulates direct-current power during an alternating-current to direct-current conversion; a bus current detector that detects a bus current flowing between either of the direct-current power supply terminals and the smoothing capacitor; a power supply phase detector that detects a phase of an input power supply; a base drive signal generator that generates base drive signals that perform ON/OFF control of the regenerative switching elements based on a power supply phase detected by the power supply phase detection unit; a regeneration controller that performs a start and stop process of a power regenerative operation based on a detection result of the bus current detector and the base drive signals; and an overload detector that detects overload of a power regenerative converter based on the detection result of the bus current detector.

Power regenerative converter and motor control device

A switching power supply circuit includes a switching element connected to a primary winding wire of a transformer in series, capacitors connected to secondary winding wires of the transformer via diodes, and an IC for power supply control that controls ON/OFF operation of the switching element on the basis of a charged voltage of the capacitors. Commanded voltages are charged in the capacitors after electric power is supplied to a main power supply, and further, after the elapse of a delay time set in advance, a control circuit, which controls the entire apparatus, controls a main circuit and a peripheral apparatus circuit to start operations.

Switching power supply circuit and control method therefor

A voltage supply apparatus includes: a primary cell; and a constant voltage supply unit. The constant voltage supply unit has set therein a voltage drop determination value, which is a threshold that is higher than a positional-data loss level and is lower than a second output voltage, which is a constant voltage at a steady voltage level that the constant voltage supply unit outputs when in a steady state. The constant voltage supply unit converts a first output voltage of the primary cell to the second output voltage and supplies it to the absolute-position detection apparatus until the first output voltage falls below the threshold. When the first output voltage falls below the threshold, the constant voltage supply unit converts the first output voltage to a third output voltage which is a voltage at the same level as the threshold, and supplies it to the absolute-position detection apparatus.

Voltage supply apparatus

The invention is related to a device for detecting insulation degradation in an inverter-driven load device, in particular a motor, the device including: zero-phase current measuring means for measuring a zero-phase current in power-feed lines, provided in the power-feed lines between an inverter device and the motor; and command control means for putting rotation of the motor on standby; wherein the zero-phase current measuring means measures the total of phase currents fed into respective phases so as not to rotate a shaft even when an external force is applied to the shaft during the rotation being on standby, whereby allowing regular detection of insulation degradation without switching over the power-feed lines connected with the load device.

Device for detecting insulation degradation

In the case where DC power from a DC power supply is converted to AC power by an inverter and supplied to an AC motor, a power compensator is connected in parallel with a DC power input portion of the inverter, and a control device of the power compensator charges/discharges a power storage device to perform a power compensation process A when power demand for the AC motor exceeds a predetermined value, and takes into account power allowance which can be inputted and outputted from the DC power supply to the power storage device and performs a power storage adjustment process B of performing auxiliary charge of the power storage device within the range of the power allowance when the power compensation process A is unnecessary.

AC motor driving apparatus

Growing community of inventors

Tokyo, Japan

Yoji Tsutsumishita