Mitsubishi Electric Corporation

Mitsubishi Electric Cornoration

Mao Kawamura

Mamoru Takikita

Kenji Hirose

Takuya Nakamura

Masayuki Kato

Yohei Matsuda

Yusuke Tsubaki

Hayato Tanabe

The power conversion device includes: a control unit that switches between the on state in which a power module is made conductive between a drain terminal and a source terminal of the power module and the off state in which the power module is made non-conductive; a resistance element connected between the control unit and a gate terminal of the power module; and a bypass circuit in which a drain terminal of a semiconductor switching element provided for each power module is connected to the gate terminal of the power module, and a source terminal of the semiconductor switching element is connected to the source terminal of the power module, in which the control unit switches the semiconductor switching element of the bypass circuit to the on state when the power module is switched to the off state, thereby reducing occurrence of an erroneous turn-on of the power module.

Power conversion device with bypass of a gate current

A semiconductor device includes: a first circuit including semiconductor switching elements connected in parallel, each semiconductor switching element having a first electrode, a second electrode, and a third electrode and being configured to be controlled, according to a voltage between the first electrode and the third electrode, to attain conduction or non-conduction between the second electrode and the third electrode; and a control unit connected to the first electrode of each semiconductor switching element and configured to control the voltage between the first electrode and the third electrode. The semiconductor device is configured to satisfy a first condition that an impedance Zg on a first path between the first electrodes of the respective semiconductor switching elements is higher, by at least a set value, than an impedance Zs on a third path making connection between the third electrodes of the respective semiconductor switching elements.

Semiconductor device and power conversion apparatus

The power conversion device includes: a boost, converter which includes a magnetically-coupled reactor and a plurality of semiconductor switching elements connected to the magnetically-coupled reactor; an inverter; a cooler for cooling the magnetically-coupled reactor; a bus bar which is a conductive wiring member; and a current sensor for detecting a magnetic flux generated around the bus bar. The magnetically-coupled reactor includes a first winding, a second winding, and a core for magnetically coupling the first winding and the second winding. The core has a composite magnetic body containing soft magnetic powder and a binder, and at least parts of the first winding and the second winding are embedded in the composite magnetic body. The cooler is provided in contact with the magnetically-coupled reactor. The current sensor is provided on a side opposite to the magnetically-coupled reactor with the cooler therebetween.

Power conversion device

In order to cause an output to be continued while protecting a DC-DC converter including a temperature detector from overheating, without stopping an operation or excessively reducing an output, even when an abnormality has occurred in a cooler or the temperature detector has failed, a controller sets current values at which a control using droop characteristics is started in a multiple of stages in accordance with temperature values, and carries out the control using droop characteristics by switching the current value in accordance with a temperature detected by the temperature detector.

Power conversion device with temperature control

In an electrical power conversion device including a step-up or boost converter and an inverter, a small-size and inexpensive power conversion device is provided in which its reactor and capacitors can be made more compact. The electrical power conversion device includes a boost converter connected to an electric energy storage device, an inverter connected on an output side of the boost converter, and a controller for performing a turn-on/turn-off control on semiconductor switching devices of the boost converter and semiconductor switching devices of the inverter; and the semiconductor switching devices of the boost converter are made of an SiC semiconductor, and the semiconductor switching devices of the inverter are made of an Si semiconductor.

Provided is a power conversion device using a magnetic coupling reactor and being capable of reducing the number of parts and reducing the size of not only the magnetic coupling reactor but also an input capacitor. The magnetic coupling reactor is connected between a semiconductor switch element group, which executes power conversion, and the input capacitor. The coupling factor of two reactors in the magnetic coupling reactor is kept to a value equal to or less than a set value, for example, 0.8. The set value takes into consideration an area in which a ripple current of the input capacitor increases rapidly in response to a rise in coupling factor. The ripple current flowing in the input capacitor is reduced by thus setting the coupling factor.

The present application provides a power conversion device such that input current and output current can be accurately estimated without providing a special circuit. A DC-DC converter including a control unit and semiconductor switching elements is such that a current detecting current transformer is connected in series between a high voltage battery and the semiconductor switching elements, in addition to which the DC-DC converter includes a current-to-voltage conversion circuit on a secondary side of the current transformer, and the control unit estimates an input current from an AD conversion value input from the current-to-voltage conversion circuit.

A noise filter is provided with a filter circuit including a first condenser and a second condenser; the first condenser and the second condenser are connected in parallel with each other by a first wiring lead for connecting one terminal of the first condenser with one terminal of the second condenser and a second wiring lead for connecting the other terminal of the first condenser with the other terminal of the second condenser; the first wiring lead and the second wiring lead are arranged in such a way as to intersect each other odd-number times.

Noise filter

An isolated DC/DC converter () includes a full-bridge type switching circuit. A primary winding of a transformer () and a resonance reactor () are connected in series to each other. Another end of each of the primary winding and the resonance reactor () is connected to one of middle points between switching elements. First and second surge suppression diodes (Dand D) are provided to a node between the resonance reactor () and the primary winding of the transformer () and between a positive side and a negative side of a capacitor (). This configuration suppresses a surge voltage applied to the transformer by releasing surge energy of the resonance reactor () caused by a recovery of rectifying diodes (Dto D) on a secondary side of the transformer () via the surge suppression diodes (Dand D).

In-vehicle charger and surge-suppression method in in-vehicle charger

A noise filter inserted between the power source side and the load side of a main circuit for which noise is reduced to attenuate noise of the main circuit using a filter circuit including the coil and the capacitor. In the noise filter, the board ground pattern is separated into a plurality of board ground patterns, the separated board ground patterns are connected to a common ground member present outside the board, the separated board ground patterns are formed as solid patterns, and adjacent board ground patterns of the separated board ground patterns are disposed so as to have a spacing equal to or less than a predetermined distance.

A Si diode is used as a rectifying diode on a transformer secondary side of an isolated DC/DC converter, and a high-voltage Schottky barrier diode made of a wide bandgap semiconductor is used as a free-wheeling diode arranged between a rectifier circuit and a smoothing reactor. Thus, there may be provided an in-vehicle charger capable of suppressing a diode recovery surge voltage with a circuit configuration that is simpler and suppressed in cost increase as compared to a case where a related-art synchronous rectifier circuit system is employed.

In-vehicle charger

The number of constituent components is reduced so as to provide a small-size and inexpensive electric-power conversion system. The electric-power conversion system is provided with an inverter circuit () connected with the rear stage of an AC power source, a smoothing capacitor () connected with the rear stage of the inverter circuit () by way of a rectifying device (), a charging switch () that is connected with the front stage of the inverter circuit (), that inputs an electric quantity based on an output of the AC power source () to the inverter circuit () when being turned on, and that cuts off an input of the electric quantity to the inverter circuit () when being turned off, and an inrush current prevention circuit () having an inrush current prevention switch () and an inrush current prevention resistor () that is connected in series with the rear stage of the inrush current prevention switch (); the electric-power conversion system is characterized in that the inrush current prevention circuit () is connected in parallel with the charging switch ().

Growing community of inventors

Tokyo, Japan

Mao Kawamura