Mitsubishi Electric Corporation

Katsuhiko Saito

Masahiro Fukuda

Norikazu Ito

Shigeo Umehara

Katsuyuki Amano

Yosuke Shinomoto

Takuya Shimomugi

Yasushi Kuwabara

Daisuke Suzuki

Koichi Arisawa

Shinya Matsushita

Mitsuo Kashima

Makoto Tanikawa

Tomomi Higashikawa

Ryuji Momose

Masato Handa

Hitoshi Tanifuji

Yu Otorii

A motor drive apparatus includes: inverter modules equivalent in number to phases of a motor; and a control unit that generates a PWM signal for driving the inverter modules by using PWM. Each of the inverter modules includes: a plurality of pairs of switching elements, each pair of switching elements including two switching elements connected in series; a drive circuit; and a protection circuit. The plurality of pairs of switching elements is connected in parallel, and power GNDs that are reference terminals of the plurality of pairs of switching elements, a control GND that is a reference terminal of the drive circuit, and a terminal for overcurrent fault input in the protection circuit are independently exposed to the outside. The power GNDs and the control GND are connected to a single point on a printed circuit board by a wiring pattern.

Motor drive apparatus, refrigeration cycle apparatus and air conditioner

A motor drive apparatus which drives a motor includes inverter modules equal in number to phases of the motor. Each of the inverter modules includes a plurality of switching element pairs. Each of the switching element pairs is defined by two switching elements connected in series. In each of the inverter modules, the plurality of switching element pairs are connected in parallel, and each of resistance values of gate resistors connected to the switching elements is set for the corresponding switching element connected thereto.

Motor drive apparatus and air conditioner

There are provided the same number of inverter modules as the number of phases of a motor, and an inverter control unit that generates PWM signals used to drive the inverter modules in PWM. Three phase outputs from each of the inverter modules are coupled to form a phase output signal for one phase of the motor while capacitors are mounted between control GNDs of the inverter modules and power GNDs of the inverter modules. Consequently, even if a surge voltage is generated in a GND wiring at the time of a switching operation of switching elements in the inverter modules, the application of the surge voltage to the switching elements can be suppressed.

A cooling-abnormality detecting system in which a heat generating component and a cooling component contact each other via a contact section, and the cooling component cools the heat generating component. The cooling-abnormality detecting system includes: a heat-generating-component-temperature detecting sensor, a heat-generating-component-power-consumption detecting sensor, a cooling-component-temperature detecting sensor, and a processor that calculates a heat resistance value of the contact section between the heat generating component and the cooling component and determines the presence or absence of an abnormality in the contact section.

Cooling-abnormality detecting system

A power converter includes step-up means for varying a voltage applied by a power supply to a predetermined voltage, commutating means for performing a commutation operation for allowing a current flowing through the step-up means to flow through a second path, smoothing means for smoothing a voltage related to outputs of the step-up means and the commutating means to produce power and supplying the power to a load side, and control means for performing control related to voltage varying, such as stepping up, by the step-up means and controlling the commutation operation of the commutating means on the basis of at least one of a voltage and a current related to the step-up means.

Power converter and refrigerating and air-conditioning apparatus

A converter control device comprises: a voltage-zero-cross detection unit detecting zero cross of the alternate-current voltage and outputting a voltage zero-cross signal; a power-source-current detection unit detecting a power source current of the alternate-current power source; a bus-line-voltage detection unit detecting a bus-line voltage between terminals of the smoothing capacitor; a PWM-signal generation unit generating a PWM-signal for on/off-controlling the switching unit, based on the power-source current, the bus-line voltage and a bus-line-voltage command value as a target voltage of the bus-line voltage; a power-source voltage-state detection unit detecting a signal state of the alternate-current voltage based on the voltage zero-cross signal; and a fundamental-switching-frequency selection unit selecting a fundamental switching frequency of the PWM-signal based on the signal state of the alternate-current voltage. The PWM-signal generation unit generates the PWM-signal based on a fundamental switching signal having a fundamental switching frequency selected by the fundamental-switching-frequency selection unit.

Converter control device and air conditioner including converter control device

A DC power supply apparatus comprising: a rectifying circuit including, a first rectifying portion, a second rectifying portion, a third rectifying portion and a fourth rectifying portion; a current detection portion; a first switching portion; and a second switching portion; wherein each of the first rectifying portion cooperatively operating with the first switching portion and the second rectifying portion cooperatively operating with the second switching portion is a semiconductor element which is formed by using a Schottky junction formed between silicon carbide or gallium nitride and metal and has a withstanding voltage property with respect to a voltage of an AC power supply.

DC power supply apparatus

A switching-element drive circuit that is configured to be applied to a power converter includes: a switching element; and a control unit that controls an operation of the switching element. The control unit includes a drive-voltage control unit that is configured to be capable of changing a switching speed of the switching element based on a power supply current.

Switching-element drive circuit

An inverter controller controlling an inverter main circuit, the inverter controller including: a PWM signal generating part which generates a PWM signal to control on-off of a plurality of switching elements configuring the inverter main circuit; an operating state detecting part which detects an operating state of a load based on a direct current bus voltage of the inverter main circuit, a motor current which flows between the inverter main circuit and the load and an operation instruction to the load; a gate resistance selecting signal generating part which generates a gate resistance selecting signal corresponding to the operating state of the load; and a gate resistance selecting part which selects gate resistances connected to gate terminals of the switching elements of the inverter main circuit by using the gate resistance selecting signal.

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Tokyo, Japan

Katsuhiko Saito